14 CFR Appendix E to Part 420 - Tables for Explosive Site Plan

Code of Federal Regulations, 2010 CFR

2010-01-01

.... Table E-2—Liquid Propellant Explosive Equivalents Propellant combinations Explosive equivalent LO2/LH2 The larger of: 8W2/3 where W is the weight of LO2/LH2, or14% of W. LO2/LH2 + LO2/RP-1 Sum of (20% for LO2/RP-1) + the larger of: 8W2/3 where W is the weight of LO2/LH2, or14% of W. LO2/R-1 20% of W up to...

Oxygen Compatibility Testing of Composite Materials

NASA Technical Reports Server (NTRS)

Graf, Neil A.; Hudgins, Richard J.; McBain, Michael

2000-01-01

The development of polymer composite liquid oxygen LO2 tanks is a critical step in creating the next generation of launch vehicles. Future launch vehicles need to minimize the gross liftoff weight (GLOW), which is possible due to the 25%-40% reduction in weight that composite materials could provide over current aluminum technology. Although a composite LO2 tank makes these weight savings feasible, composite materials have not historically been viewed as "LO2 compatible." To be considered LO2 compatible, materials must be selected that will resist any type of detrimental, combustible reaction when exposed to usage environments. This is traditionally evaluated using a standard set of tests. However, materials that do not pass the standard tests can be shown to be safe for a particular application. This paper documents the approach and results of a joint NASA/Lockheed Martin program to select and verify LO2 compatible composite materials for liquid oxygen fuel tanks. The test approach developed included tests such as mechanical impact, particle impact, puncture, electrostatic discharge, friction, and pyrotechnic shock. These tests showed that composite liquid oxygen tanks are indeed feasible for future launch vehicles.

Visualization of Detergent Solubilization of Membranes: Implications for the Isolation of Rafts

PubMed Central

Garner, Ashley E.; Smith, D. Alastair; Hooper, Nigel M.

2008-01-01

Although different detergents can give rise to detergent-resistant membranes of different composition, it is unclear whether this represents domain heterogeneity in the original membrane. We compared the mechanism of action of five detergents on supported lipid bilayers composed of equimolar sphingomyelin, cholesterol, and dioleoylphosphatidylcholine imaged by atomic force microscopy, and on raft and nonraft marker proteins in live cells imaged by confocal microscopy. There was a marked correlation between the detergent solubilization of the cell membrane and that of the supported lipid bilayers. In both systems Triton X-100 and CHAPS (3-[(3-cholamidopropyl)dimethylammonio]-1-propanesulfonate) distinguished between the nonraft liquid-disordered (ld) and raft liquid ordered (lo) lipid phases by selectively solubilizing the ld phase. A higher concentration of Lubrol was required, and not all the ld phase was solubilized. The solubilization by Brij 96 occurred by a two-stage mechanism that initially resulted in the solubilization of some ld phase and then progressed to the solubilization of both ld and lo phases simultaneously. Octyl glucoside simultaneously solubilized both lo and ld phases. These data show that the mechanism of membrane solubilization is unique to an individual detergent. Our observations have significant implications for using different detergents to isolate membrane rafts from biological systems. PMID:17933878

Hepatitis C virus p7 mediates membrane-to-membrane adhesion.

PubMed

Lee, Gi Young; Lee, Sora; Lee, Hye-Ra; Yoo, Young Do

2016-09-01

Viroporin p7 of the hepatitis C virus (HCV) acts as an ion channel for pH equilibration to stabilize HCV particles; most studies of p7 have focused on this role. However, pH equilibration by p7 via its ion channel activity does not fully explain the importance of p7 in HCV particle production. Indeed, several researchers have suggested p7 to have an unidentified ion channel-independent function. Here, we show that p7 has a novel role as a lipid raft adhesion factor, which is independent of its ion channel activity. We found that p7 targets not only the liquid-disordered (Ld) phase, but also the negatively-charged liquid-ordered (Lo) phase that can be represented as a lipid raft. p7 clusters at the phase boundary of the neutral Ld phase and the negatively-charged Lo phase. Interestingly, p7 targeting the Lo phase facilitates membrane-to-membrane adhesion, and this activity is not inhibited by p7 ion channel inhibitors. Our results demonstrated that HCV p7 has dual roles as a viroporin and as a lipid raft adhesion factor. This ion channel-independent function of p7 might be an attractive target for development of anti-HCV compounds. Copyright © 2016 Elsevier B.V. All rights reserved.

Visualization of detergent solubilization of membranes: implications for the isolation of rafts.

PubMed

Garner, Ashley E; Smith, D Alastair; Hooper, Nigel M

2008-02-15

Although different detergents can give rise to detergent-resistant membranes of different composition, it is unclear whether this represents domain heterogeneity in the original membrane. We compared the mechanism of action of five detergents on supported lipid bilayers composed of equimolar sphingomyelin, cholesterol, and dioleoylphosphatidylcholine imaged by atomic force microscopy, and on raft and nonraft marker proteins in live cells imaged by confocal microscopy. There was a marked correlation between the detergent solubilization of the cell membrane and that of the supported lipid bilayers. In both systems Triton X-100 and CHAPS (3-[(3-cholamidopropyl)dimethylammonio]-1-propanesulfonate) distinguished between the nonraft liquid-disordered (l(d)) and raft liquid ordered (l(o)) lipid phases by selectively solubilizing the l(d) phase. A higher concentration of Lubrol was required, and not all the l(d) phase was solubilized. The solubilization by Brij 96 occurred by a two-stage mechanism that initially resulted in the solubilization of some l(d) phase and then progressed to the solubilization of both l(d) and l(o) phases simultaneously. Octyl glucoside simultaneously solubilized both l(o) and l(d) phases. These data show that the mechanism of membrane solubilization is unique to an individual detergent. Our observations have significant implications for using different detergents to isolate membrane rafts from biological systems.

A lunar transportation system

NASA Technical Reports Server (NTRS)

1986-01-01

Due to large amounts of oxygen required for space travel, a method of mining, transporting, and storing this oxygen in space would facilitate further space exploration. The following project deals specifically with the methods for transporting liquid oxygen from the lunar surface to the Lunar Orbit (LO) space station, and then to the Lower Earth Orbit (LEO) space station. Two vehicles were designed for operation between the LEO and LO space stations. The first of these vehicles is an aerobraked design vehicle. The Aerobrake Orbital Transfer Vehicle (OTV) is capable of transporting 5000 lbm of payload to LO while returning to LEO with 60,000 lbm of liquid oxygen, and thus meet mission requirements. The second vehicle can deliver 18,000 lbm of payload to LO and is capable of bringing 60,000 lbm of liquid oxygen back to LEO. A lunar landing vehicle was also designed for operation between LO and the established moon base. The use of an electromagnetic railgun as a method for launching the lunar lander was also investigated. The feasibility of the railgun is doubtful at this time. A system of spheres was also designed for proper storing and transporting of the liquid oxygen. The system assumes a safe means for transferring the liquid oxygen from tank to tank is operational. A sophisticated life support system was developed for both the OTV and the lunar lander. This system focuses on such factors as the vehicle environment, waste management, water requirements, food requirements, and oxygen requirements.

Anomalous partitioning of water in coexisting liquid phases of lipid multilayers near 100% relative humidity

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ma, Yicong; Ghosh, Sajal K.; Bera, Sambhunath

2015-11-30

X-ray diffraction is used to determine the hydration dependence of a ternary mixture lipid multilayer structure which has phase separated into liquid-ordered (Lo) and liquid-disordered (Ld) phases. An anomaly is observed in the swelling behavior of the Ld phase at a relative humidity (RH) close to 100%, which is different from the anomalous swelling happens close to the main lipid gel-fluid transition. The lamellar repeat distance of the Ld phase swells by an extra 4 Å, well beyond the equilibrium spacing predicted by the inter-bilayer forces. This anomalous swelling is caused by the hydrophobic mismatch energy at the domain boundaries,more » which produces surprisingly long range effect.« less

DOD Ammunition and Explosives Safety Standards

DTIC Science & Technology

2004-10-05

chemical canister, 3 x 10- 5 1 x 10- 4 1 x 10- 5 3 x 10-3 3 x 10-3 air purifying protective mask will be on hand for escape . ( The M9, M17 or M40...1,2, 3, 4 , 5 8 8 9 ENERGETIC LIQUIDS STATIC TEST STANDS RANGE LAUNCH LO 2 /LH 2 See Note 6 See Note 6 LO 2 /LH 2 + LO 2 /RP-1 Sum of (see...liquids provided they comply with the construction and siting requirements of chapters 5 and 9 , respectively for Hazard Division 1.1. ECM must be sited

Temperature- and pressure-dependent infrared spectroscopy of 1-butyl-3-methylimidazolium trifluoromethanesulfonate: A dipolar coupling theory analysis

NASA Astrophysics Data System (ADS)

Burba, Christopher M.; Chang, Hai-Chou

2018-03-01

Continued growth and development of ionic liquids requires a thorough understanding of how cation and anion molecular structure defines the liquid structure of the materials as well as the various properties that make them technologically useful. Infrared spectroscopy is frequently used to assess molecular-level interactions among the cations and anions of ionic liquids because the intramolecular vibrational modes of the ions are sensitive to the local potential energy environments in which they reside. Thus, different interaction modes among the ions may lead to different spectroscopic signatures in the vibrational spectra. Charge organization present in ionic liquids, such as 1-butyl-3-methylimidazolium trifluoromethanesulfonate ([C4mim]CF3SO3), is frequently modeled in terms of a quasicrystalline structure. Highly structured quasilattices enable the dynamic coupling of vibrationally-induced dipole moments to produce optical dispersion and transverse optical-longitudinal optical (TO-LO) splitting of vibrational modes of the ionic liquid. According to dipolar coupling theory, the degree of TO-LO splitting is predicted to have a linear dependence on the number density of the ionic liquid. Both temperature and pressure will affect the number density of the ionic liquid and, therefore, the amount of TO-LO splitting for this mode. Therefore, we test these relationships through temperature- and pressure-dependent FT-IR spectroscopic studies of [C4mim]CF3SO3, focusing on the totally symmetric Ssbnd O stretching mode for the anion, νs(SO3). Increased temperature decreases the amount of TO-LO splitting for νs(SO3), whereas elevated pressure is found to increase the amount of band splitting. In both cases, the experimental observations follow the general predictions of dipolar coupling theory, thereby supporting the quasilattice model for this ionic liquid.

Molecular dynamics exploration of poration and leaking caused by Kalata B1 in HIV-infected cell membrane compared to host and HIV membranes.

PubMed

Nawae, Wanapinun; Hannongbua, Supa; Ruengjitchatchawalya, Marasri

2017-06-15

The membrane disruption activities of kalata B1 (kB1) were investigated using molecular dynamics simulations with membrane models. The models were constructed to mimic the lipid microdomain formation in membranes of HIV particle, HIV-infected cell, and host cell. The differences in the lipid ratios of these membranes caused the formation of liquid ordered (lo) domains of different sizes, which affected the binding and activity of kB1. Stronger kB1 disruptive activity was observed for the membrane with small sized lo domain. Our results show that kB1 causes membrane leaking without bilayer penetration. The membrane poration mechanism involved in the disorganization of the lo domain and in cholesterol inter-leaflet translocation is described. This study enhances our understanding of the membrane activity of kB1, which may be useful for designing novel and potentially therapeutic peptides based on the kB1 framework.

Evolution and development of model membranes for physicochemical and functional studies of the membrane lateral heterogeneity.

PubMed

Morigaki, Kenichi; Tanimoto, Yasushi

2018-03-14

One of the main questions in the membrane biology is the functional roles of membrane heterogeneity and molecular localization. Although segregation and local enrichment of protein/lipid components (rafts) have been extensively studied, the presence and functions of such membrane domains still remain elusive. Along with biochemical, cell observation, and simulation studies, model membranes are emerging as an important tool for understanding the biological membrane, providing quantitative information on the physicochemical properties of membrane proteins and lipids. Segregation of fluid lipid bilayer into liquid-ordered (Lo) and liquid-disordered (Ld) phases has been studied as a simplified model of raft in model membranes, including giant unilamellar vesicles (GUVs), giant plasma membrane vesicles (GPMVs), and supported lipid bilayers (SLB). Partition coefficients of membrane proteins between Lo and Ld phases were measured to gauze their affinities to lipid rafts (raftophilicity). One important development in model membrane is patterned SLB based on the microfabrication technology. Patterned Lo/Ld phases have been applied to study the partition and function of membrane-bound molecules. Quantitative information of individual molecular species attained by model membranes is critical for elucidating the molecular functions in the complex web of molecular interactions. The present review gives a short account of the model membranes developed for studying the lateral heterogeneity, especially focusing on patterned model membranes on solid substrates. Copyright © 2018 Elsevier B.V. All rights reserved.

The Molecular Structure of Human Red Blood Cell Membranes from Highly Oriented, Solid Supported Multi-Lamellar Membranes

PubMed Central

Himbert, Sebastian; Alsop, Richard J.; Rose, Markus; Hertz, Laura; Dhaliwal, Alexander; Moran-Mirabal, Jose M.; Verschoor, Chris P.; Bowdish, Dawn M. E.; Kaestner, Lars; Wagner, Christian; Rheinstädter, Maikel C.

2017-01-01

We prepared highly oriented, multi-lamellar stacks of human red blood cell (RBC) membranes applied on silicon wafers. RBC ghosts were prepared by hemolysis and applied onto functionalized silicon chips and annealed into multi-lamellar RBC membranes. High resolution X-ray diffraction was used to determine the molecular structure of the stacked membranes. We present direct experimental evidence that these RBC membranes consist of nanometer sized domains of integral coiled-coil peptides, as well as liquid ordered (lo) and liquid disordered (ld) lipids. Lamellar spacings, membrane and hydration water layer thicknesses, areas per lipid tail and domain sizes were determined. The common drug aspirin was added to the RBC membranes and found to interact with RBC membranes and preferably partition in the head group region of the lo domain leading to a fluidification of the membranes, i.e., a thinning of the bilayers and an increase in lipid tail spacing. Our results further support current models of RBC membranes as patchy structures and provide unprecedented structural details of the molecular organization in the different domains. PMID:28045119

The Molecular Structure of Human Red Blood Cell Membranes from Highly Oriented, Solid Supported Multi-Lamellar Membranes

NASA Astrophysics Data System (ADS)

Himbert, Sebastian; Alsop, Richard J.; Rose, Markus; Hertz, Laura; Dhaliwal, Alexander; Moran-Mirabal, Jose M.; Verschoor, Chris P.; Bowdish, Dawn M. E.; Kaestner, Lars; Wagner, Christian; Rheinstädter, Maikel C.

2017-01-01

We prepared highly oriented, multi-lamellar stacks of human red blood cell (RBC) membranes applied on silicon wafers. RBC ghosts were prepared by hemolysis and applied onto functionalized silicon chips and annealed into multi-lamellar RBC membranes. High resolution X-ray diffraction was used to determine the molecular structure of the stacked membranes. We present direct experimental evidence that these RBC membranes consist of nanometer sized domains of integral coiled-coil peptides, as well as liquid ordered (lo) and liquid disordered (ld) lipids. Lamellar spacings, membrane and hydration water layer thicknesses, areas per lipid tail and domain sizes were determined. The common drug aspirin was added to the RBC membranes and found to interact with RBC membranes and preferably partition in the head group region of the lo domain leading to a fluidification of the membranes, i.e., a thinning of the bilayers and an increase in lipid tail spacing. Our results further support current models of RBC membranes as patchy structures and provide unprecedented structural details of the molecular organization in the different domains.

Numerical Investigation of LO2 and LCH4 Storage Tanks on the Lunar Surface

NASA Technical Reports Server (NTRS)

Moder, Jeff; Barsi, Stephen; Kassemi, Mohammad

2008-01-01

Currently NASA is developing technologies to enable human exploration of the lunar surface for duration of up to 210 days. While trade studies are still underway, a cryogenic ascent stage using liquid oxygen (LO2) and liquid methane (LCH4) is being considered for the Altair lunar lander. For a representative Altair cryogenic ascent stage, we present a detailed storage analysis of the LO2 and LCH4 propellant tanks on the lunar surface for durations of up to 210 days. Both the LO2 and LCH4 propellant tanks are assumed to be pressurized with gaseous helium at launch. A two-phase lumped-vapor computational fluid dynamics model has been developed to account for the presence of a noncondensable gas in the ullage. The CFD model is used to simulate the initial pressure response of the propellant tanks while they are subjected to representative heat leak rates on the lunar surface. Once a near stationary state is achieved within the liquid phase, multizone model is used to extrapolate the solution farther in time. For fixed propellant mass and tank size, the long-term pressure response for different helium mass fractions in both the LO2 and LCH4 tanks is examined.

Behavior of Bilayer Leaflets in Asymmetric Model Membranes: Atomistic Simulation Studies

DOE PAGES

Tian, Jianhui; Nickels, Jonathan; Katsaras, John; ...

2016-04-27

Spatial organization within lipid bilayers is an important feature for a range of biological processes. Leaflet compositional asymmetry and lateral lipid organization are just two of the ways in which membrane structure appears to be more complex than initially postulated by the fluid mosaic model. This raises the question of how the phase behavior in one bilayer leaflet may affect the apposing leaflet and how one begins to construct asymmetric model systems to investigate these interleaflet interactions. In this paper, we report on all-atom molecular dynamics simulations (a total of 4.1 μs) of symmetric and asymmetric bilayer systems composed ofmore » liquid-ordered (Lo) or liquid-disordered (Ld) leaflets, based on the nanodomain-forming POPC/DSPC/cholesterol system. We begin by analyzing an asymmetric bilayer with leaflets derived from simulations of symmetric Lo and Ld bilayers. In this system, we observe that the properties of the Lo and Ld leaflets are similar to those of the Lo and Ld leaflets in corresponding symmetric systems. However, it is not obvious that mixing the equilibrium structures of their symmetric counterparts is the most appropriate way to construct asymmetric bilayers nor that these structures will manifest interleaflet couplings that lead to domain registry/antiregistry. We therefore constructed and simulated four additional asymmetric bilayer systems by systematically adding or removing lipids in the Ld leaflet to mimic potential density fluctuations. We find that the number of lipids in the Ld leaflet affects its own properties, as well as those of the apposing Lo leaflet. Collectively, the simulations reveal the presence of weak acyl chain interdigitation across bilayer leaflets, suggesting that interdigitation alone does not contribute significantly to the interleaflet coupling in nonphase-separated bilayers of this chemical composition. Finally, however, the properties of both leaflets appear to be sensitive to changes in in-plane lipid packing, possibly providing a mechanism for interleaflet coupling by modulating local density and/or curvature fluctuations.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tian, Jianhui; Nickels, Jonathan; Katsaras, John

Spatial organization within lipid bilayers is an important feature for a range of biological processes. Leaflet compositional asymmetry and lateral lipid organization are just two of the ways in which membrane structure appears to be more complex than initially postulated by the fluid mosaic model. This raises the question of how the phase behavior in one bilayer leaflet may affect the apposing leaflet and how one begins to construct asymmetric model systems to investigate these interleaflet interactions. In this paper, we report on all-atom molecular dynamics simulations (a total of 4.1 μs) of symmetric and asymmetric bilayer systems composed ofmore » liquid-ordered (Lo) or liquid-disordered (Ld) leaflets, based on the nanodomain-forming POPC/DSPC/cholesterol system. We begin by analyzing an asymmetric bilayer with leaflets derived from simulations of symmetric Lo and Ld bilayers. In this system, we observe that the properties of the Lo and Ld leaflets are similar to those of the Lo and Ld leaflets in corresponding symmetric systems. However, it is not obvious that mixing the equilibrium structures of their symmetric counterparts is the most appropriate way to construct asymmetric bilayers nor that these structures will manifest interleaflet couplings that lead to domain registry/antiregistry. We therefore constructed and simulated four additional asymmetric bilayer systems by systematically adding or removing lipids in the Ld leaflet to mimic potential density fluctuations. We find that the number of lipids in the Ld leaflet affects its own properties, as well as those of the apposing Lo leaflet. Collectively, the simulations reveal the presence of weak acyl chain interdigitation across bilayer leaflets, suggesting that interdigitation alone does not contribute significantly to the interleaflet coupling in nonphase-separated bilayers of this chemical composition. Finally, however, the properties of both leaflets appear to be sensitive to changes in in-plane lipid packing, possibly providing a mechanism for interleaflet coupling by modulating local density and/or curvature fluctuations.« less

Liquid Rocket Booster Study. Volume 2, Book 1

NASA Technical Reports Server (NTRS)

1989-01-01

The recommended Liquid Rocket Booster (LRB) concept is shown which uses a common main engine with the Advanced Launch System (ALS) which burns LO2 and LH2. The central rationale is based on the belief that the U.S. can only afford one big new rocket engine development in the 1990's. A LO2/LH2 engine in the half million pound thrust class could satisfy STS LRB, ALS, and Shuttle C (instead of SSMEs). Development costs and higher production rates can be shared by NASA and USAF. If the ALS program does not occur, the LO2/RP-1 propellants would produce slight lower costs for and STS LRB. When the planned Booster Engine portion of the Civil Space Transportation Initiatives has provided data on large pressure fed LO2/RP-1 engines, then the choice should be reevaluated.

Solid-liquid staged combustion space boosters

NASA Technical Reports Server (NTRS)

Culver, D. W.

1990-01-01

NASA has begun to evaluate solid-liquid hybrid propulsion for launch vehicle booster. A three-phase program was outlined to identify, acquire, and demonstrate technology needed to approximate solid and liquid propulsion state of the art. Aerojet has completed a Phase 1 study and recommends a solid-liquid staged combustion concept in which turbopump fed LO2 is burned with fuel-rich solid propellant effluent in aft-mounted thrust chambers.These reasonably sized thrust chambers are LO2 regeneratively cooled, supplemented with fuel-rich barrier cooling. Turbopumps are driven by the resulting GO2 coolant in an expander-bleed-burnoff cycle. Turbine exhaust pressurizes the LO2 tankage directly, and the excess is bled into supersonic nozzle splitlines, where it combusts with the fuel rich boundary layer. Thrust vector control is enhanced by supersonic nozzle movement on flexseal mounts. Every hybrid solid-liquid concept examined improves booster energy management and launch propellant safety compared to current solid boosters. Solid-liquid staged combustion improves hybrid performance by improving both combustion efficiency and combustion stability, especially important for large boosters. These improvements result from careful fluid management and use of smaller combustors. The study shows NASA safety, reliability, cost, and performance criteria are best met with this concept, wherein simple hardware relies on several separate emerging technologies, all of which have been demonstrated successfully.

Liquid rocket booster study. Volume 2, book 5, appendix 9: LRB alternate applications and evolutionary growth

NASA Technical Reports Server (NTRS)

1989-01-01

The analyses performed in assessing the merit of the Liquid Rocket Booster concept for use in alternate applications such as for Shuttle C, for Standalone Expendable Launch Vehicles, and possibly for use with the Air Force's Advanced Launch System are presented. A comparison is also presented of the three LRB candidate designs, namely: (1) the LO2/LH2 pump fed, (2) the LO2/RP-1 pump fed, and (3) the LO2/RP-1 pressure fed propellant systems in terms of evolution along with design and cost factors, and other qualitative considerations. A further description is also presented of the recommended LRB standalone, core-to-orbit launch vehicle concept.

Fiber optic Raman sensor to monitor the concentration ratio of nitrogen and oxygen in a cryogenic mixture

NASA Astrophysics Data System (ADS)

Tiwari, Vidhu S.; Kalluru, Rajamohan R.; Yueh, Fang Y.; Singh, Jagdish P.; St. Cyr, William; Khijwania, Sunil K.

2007-06-01

A spontaneous Raman scattering optical fiber sensor was developed for a specific need of the National Aeronautics and Space Administration (NASA) for long-term detection and monitoring of the purity of liquid oxygen (LO2) in the oxidizer feed line during ground testing of rocket engines. The Raman peak intensity ratios for liquid nitrogen (LN2) and LO2 with varied weight ratios (LN2/LO2) were analyzed for their applicability to impurity sensing. The study of the sensor performance with different excitation light sources has helped to design a miniaturized, cost-effective system for this application. The optimal system response time of this miniaturized sensor for LN2/LO2 measurement was found to be in the range of a few seconds. It will need to be further reduced to the millisecond range for real-time, quantitative monitoring of the quality of cryogenic fluids in a harsh envioronment.

Sloshing in the Liquid Hydrogen and Liquid Oxygen Propellant Tanks After Main Engine Cut Off

NASA Technical Reports Server (NTRS)

Kim, Sura; West, Jeff

2011-01-01

NASA Marshall Space Flight Center is designing and developing the Main Propulsion System (MPS) for Ares launch vehicles. Propellant sloshing in the liquid hydrogen (LH2) and liquid oxygen (LO2) propellant tanks after Main Engine Cut Off (MECO) was modeled using the Volume of Fluid (VOF) module of the computational fluid dynamics code, CFD-ACE+. The present simulation shows that there is substantial sloshing side forces acting on the LH2 tank during the deceleration of the vehicle after MECO. The LH2 tank features a side wall drain pipe. The side loads result from the residual propellant mass motion in the LH2 tank which is initiated by the stop of flow into the drain pipe at MECO. The simulations show that radial force on the LH2 tank wall is less than 50 lbf and the radial moment calculated based up through the center of gravity of the vehicle is predicted to be as high as 300 lbf-ft. The LO2 tank features a bottom dome drain system and is equipped with sloshing baffles. The remaining LO2 in the tank slowly forms a liquid column along the centerline of tank under the zero gravity environments. The radial force on the LO2 tank wall is predicted to be less than 100 lbf. The radial moment calculated based on the center of gravity of the vehicle is predicted as high as 4500 lbf-ft just before MECO and dropped down to near zero after propellant draining stopped completely.

Size and mobility of lipid domains tuned by geometrical constraints

PubMed Central

Schütte, Ole M.; Mey, Ingo; Savić, Filip; Geil, Burkhard; Janshoff, Andreas

2017-01-01

In the plasma membrane of eukaryotic cells, proteins and lipids are organized in clusters, the latter ones often called lipid domains or “lipid rafts.” Recent findings highlight the dynamic nature of such domains and the key role of membrane geometry and spatial boundaries. In this study, we used porous substrates with different pore radii to address precisely the extent of the geometric constraint, permitting us to modulate and investigate the size and mobility of lipid domains in phase-separated continuous pore-spanning membranes (PSMs). Fluorescence video microscopy revealed two types of liquid-ordered (lo) domains in the freestanding parts of the PSMs: (i) immobile domains that were attached to the pore rims and (ii) mobile, round-shaped lo domains within the center of the PSMs. Analysis of the diffusion of the mobile lo domains by video microscopy and particle tracking showed that the domains’ mobility is slowed down by orders of magnitude compared with the unrestricted case. We attribute the reduced mobility to the geometric confinement of the PSM, because the drag force is increased substantially due to hydrodynamic effects generated by the presence of these boundaries. Our system can serve as an experimental test bed for diffusion of 2D objects in confined geometry. The impact of hydrodynamics on the mobility of enclosed lipid domains can have great implications for the formation and lateral transport of signaling platforms. PMID:28696315

Liquid Oxygen/Liquid Methane Integrated Propulsion System Test Bed

NASA Technical Reports Server (NTRS)

Flynn, Howard; Lusby, Brian; Villemarette, Mark

2011-01-01

In support of NASA?s Propulsion and Cryogenic Advanced Development (PCAD) project, a liquid oxygen (LO2)/liquid methane (LCH4) Integrated Propulsion System Test Bed (IPSTB) was designed and advanced to the Critical Design Review (CDR) stage at the Johnson Space Center. The IPSTB?s primary objectives are to study LO2/LCH4 propulsion system steady state and transient performance, operational characteristics and to validate fluid and thermal models of a LO2/LCH4 propulsion system for use in future flight design work. Two phase thermal and dynamic fluid flow models of the IPSTB were built to predict the system performance characteristics under a variety of operating modes and to aid in the overall system design work. While at ambient temperature and simulated altitude conditions at the White Sands Test Facility, the IPSTB and its approximately 600 channels of system instrumentation would be operated to perform a variety of integrated main engine and reaction control engine hot fire tests. The pressure, temperature, and flow rate data collected during this testing would then be used to validate the analytical models of the IPSTB?s thermal and dynamic fluid flow performance. An overview of the IPSTB design and analytical model development will be presented.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mikheev, Evgeny; Himmetoglu, Burak; Kajdos, Adam P.

We analyze and compare the temperature dependence of the electron mobility of two- and three-dimensional electron liquids in SrTiO{sub 3}. The contributions of electron-electron scattering must be taken into account to accurately describe the mobility in both cases. For uniformly doped, three-dimensional electron liquids, the room temperature mobility crosses over from longitudinal optical (LO) phonon-scattering-limited to electron-electron-scattering-limited as a function of carrier density. In high-density, two-dimensional electron liquids, LO phonon scattering is completely screened and the mobility is dominated by electron-electron scattering up to room temperature. The possible origins of the observed behavior and the consequences for approaches to improvemore » the mobility are discussed.« less

Liquid Oxygen Propellant Densification Unit Ground Tested With a Large-Scale Flight-Weight Tank for the X-33 Reusable Launch Vehicle

NASA Technical Reports Server (NTRS)

Tomsik, Thomas M.

2002-01-01

Propellant densification has been identified as a critical technology in the development of single-stage-to-orbit reusable launch vehicles. Technology to create supercooled high-density liquid oxygen (LO2) and liquid hydrogen (LH2) is a key means to lowering launch vehicle costs. The densification of cryogenic propellants through subcooling allows 8 to 10 percent more propellant mass to be stored in a given unit volume, thereby improving the launch vehicle's overall performance. This allows for higher propellant mass fractions than would be possible with conventional normal boiling point cryogenic propellants, considering the normal boiling point of LO2 and LH2.

Crystallization around solid-like nanosized docks can explain the specificity, diversity, and stability of membrane microdomains.

PubMed

de Almeida, Rodrigo F M; Joly, Etienne

2014-01-01

To date, it is widely accepted that microdomains do form in the biological membranes of all eukaryotic cells, and quite possibly also in prokaryotes. Those sub-micrometric domains play crucial roles in signaling, in intracellular transport, and even in inter-cellular communications. Despite their ubiquitous distribution, and the broad and lasting interest invested in those microdomains, their actual nature and composition, and even the physical rules that regiment their assembly still remain elusive and hotly debated. One of the most often considered models is the raft hypothesis, i.e., the partition of lipids between liquid disordered and ordered phases (Ld and Lo, respectively), the latter being enriched in sphingolipids and cholesterol. Although it is experimentally possible to obtain the formation of microdomains in synthetic membranes through Ld/Lo phase separation, there is an ever increasing amount of evidence, obtained with a wide array of experimental approaches, that a partition between domains in Ld and Lo phases cannot account for many of the observations collected in real cells. In particular, it is now commonly perceived that the plasma membrane of cells is mostly in Lo phase and recent data support the existence of gel or solid ordered domains in a whole variety of live cells under physiological conditions. Here, we present a model whereby seeds comprised of oligomerised proteins and/or lipids would serve as crystal nucleation centers for the formation of diverse gel/crystalline nanodomains. This could confer the selectivity necessary for the formation of multiple types of membrane domains, as well as the stability required to match the time frames of cellular events, such as intra- or inter-cellular transport or assembly of signaling platforms. Testing of this model will, however, require the development of new methods allowing the clear-cut discrimination between Lo and solid nanoscopic phases in live cells.

Liquid Oxygen (LO2) propellant conditioning concept testing

NASA Technical Reports Server (NTRS)

Perry, Gretchen L. E.; Orth, Michael S.; Mehta, Gopal K.

1993-01-01

Marshall Space Flight Center (MSFC) and industry contractors have undertaken activities to develop a simplified liquid oxygen (LO2) propellant conditioning concept for future expendable launch vehicles. The objective of these activities is to reduce operations costs and timelines and to improve safety of these vehicles. The approach followed has been to identify novel concepts through system level studies and demonstrate the feasibility of these concepts through small-scale and full-scale testing. Testing will also provide data for design guidelines and validation of analytical models. Four different concepts are being investigated: no-bleed, low-bleed, use of a recirculation line, and helium (He) bubbling. This investigation is being done under a Joint Institutional Research and Development (JIRAD) program currently in effect between MSFC and General Dynamics Space Systems (GDSS). A full-scale test article, which is a facsimile of a propellant feed duct with an attached section to simulate heat input from a LO2 turbopump, will be tested at the Cold Flow Facility at MSFC's West Test Area. Liquid nitrogen (LN2), which has similar properties to LO2, will be used in place of LO2 for safety and budget reasons. Work to date includes design and fabrication of the test article, design of the test facility and initial fabrication, development of a test matrix and test procedures, initial predictions of test output, and heat leak calibration and heat exchanger tests on the test article. The tests for all propellant conditioning concepts will be conducted in the summer of 1993, with the final report completed by October, 1993.

The effect of hydrostatic pressure on model membrane domain composition and lateral compressibility.

PubMed

Barriga, H M G; Law, R V; Seddon, J M; Ces, O; Brooks, N J

2016-01-07

Phase separation in ternary model membranes is known to occur over a range of temperatures and compositions and can be induced by increasing hydrostatic pressure. We have used small angle X-ray scattering (SAXS) to study phase separation along pre-determined tie lines in dioleoylphosphatidylcholine (DOPC), dipalmitoylphosphatidylcholine (DPPC) and cholesterol (CHOL) mixtures. We can unequivocally distinguish the liquid ordered (Lo) and liquid disordered (Ld) phases in diffraction patterns from biphasic mixtures and compare their lateral compressibility. The variation of tie line endpoints with increasing hydrostatic pressure was determined, at atmospheric pressure and up to 100 MPa. We find an extension and shift of the tie lines towards the DOPC rich region of the phase diagram at increased pressure, this behaviour differs slightly from that reported for decreasing temperature.

Liquid Methane/Liquid Oxygen Propellant Conditioning Feed System (PCFS) Test Rigs

NASA Technical Reports Server (NTRS)

Skaff, A.; Grasl, S.; Nguyen, C.; Hockenberry S.; Schubert, J.; Arrington, L.; Vasek, T.

2008-01-01

As part of their Propulsion and Cryogenic Advanced Development (PCAD) program, NASA has embarked upon an effort to develop chemical rocket engines which utilize non-toxic, cryogenic propellants such as liquid oxygen (LO2) and liquid methane (LCH4). This effort includes the development and testing of a 100 lbf Reaction Control Engine (RCE) that will be used to evaluate the performance of a LO2/LCH4 rocket engine over a broad range of propellant temperatures and pressures. This testing will take place at NASA-Glenn Research Center's (GRC) Research Combustion Laboratory (RCL) test facility in Cleveland, OH, and is currently scheduled to begin in late 2008. While the initial tests will be performed at sea level, follow-on testing will be performed at NASA-GRC's Altitude Combustion Stand (ACS) for altitude testing. In support of these tests, Sierra Lobo, Inc. (SLI) has designed, developed, and fabricated two separate portable propellant feed systems under the Propellant Conditioning and Feed System (PCFS) task: one system for LCH4, and one for LO2. These systems will be capable of supplying propellants over a large range of conditions from highly densified to several hundred pounds per square inch (psi) saturated. This paper presents the details of the PCFS design and explores the full capability of these propellant feed systems.

Turbopumps for cryogenic upper stage engines. [fabrication and evaluation of turbine pumps for liquid hydrogen and liquid oxygen

NASA Technical Reports Server (NTRS)

Zachary, A. T.; Csomor, A.; Tignac, L. L.

1973-01-01

Small, high-performance LO2 and LH2 turbopump assembly configurations were selected, detail designs were prepared and two of each unit were fabricated with each unit consisting of pump, turbine gas generator, and appropriate controls. Following fabrication, development testing was conducted on each type to demonstrate performance, durability, transient characteristics, and heat transfer under simulated altitude conditions. Following successful completion of development effort, the two LO2 turbopump units and one LH2 turbopump unit were acceptance tested as specified. Inspection of the units following development testing revealed no deleterious effects of testing. The test results of LO2 turbopump assembly testing correlated well with predicted performance while the LH2 turbopump test results, though generally consistent with predicted values, did show lower than anticipated developed head at the design point and in the high flow range of operation.

Liquid Oxygen/Liquid Methane Test Summary of the RS-18 Lunar Ascent Engine at Simulated Altitude Conditions at NASA White Sands Test Facility

NASA Technical Reports Server (NTRS)

Melcher, John C., IV; Allred, Jennifer K.

2009-01-01

Tests were conducted with the RS18 rocket engine using liquid oxygen (LO2) and liquid methane (LCH4) propellants under simulated altitude conditions at NASA Johnson Space Center White Sands Test Facility (WSTF). This project is part of NASA s Propulsion and Cryogenics Advanced Development (PCAD) project. "Green" propellants, such as LO2/LCH4, offer savings in both performance and safety over equivalently sized hypergolic propellant systems in spacecraft applications such as ascent engines or service module engines. Altitude simulation was achieved using the WSTF Large Altitude Simulation System, which provided altitude conditions equivalent up to approx.120,000 ft (approx.37 km). For specific impulse calculations, engine thrust and propellant mass flow rates were measured. Propellant flow rate was measured using a coriolis-style mass-flow meter and compared with a serial turbine-style flow meter. Results showed a significant performance measurement difference during ignition startup. LO2 flow ranged from 5.9-9.5 lbm/sec (2.7-4.3 kg/sec), and LCH4 flow varied from 3.0-4.4 lbm/sec (1.4-2.0 kg/sec) during the RS-18 hot-fire test series. Thrust was measured using three load cells in parallel. Ignition was demonstrated using a gaseous oxygen/methane spark torch igniter. Data was obtained at multiple chamber pressures, and calculations were performed for specific impulse, C* combustion efficiency, and thrust vector alignment. Test objectives for the RS-18 project are 1) conduct a shakedown of the test stand for LO2/methane lunar ascent engines, 2) obtain vacuum ignition data for the torch and pyrotechnic igniters, and 3) obtain nozzle kinetics data to anchor two-dimensional kinetics codes.

Cryogenic Orbital Testbed (CRYOTE) Ground Test Article, Final Report

NASA Technical Reports Server (NTRS)

Johnson, Wesley L.; Rhys, Noah O.; Bradley, David E.; Wollen, Mark; Kutter, Bernard; Gravlee, Mari; Walls, Laurie K.

2015-01-01

Liquid propulsion has been used since Robert Goddard started developing a liquid oxygen (LO2) and gasoline powered rocket and fired it in 1923 (Ref. 1). In the following decades engineers settled on the combination of liquid hydrogen (LH2) and LO2 as the most efficient propellant combination for in-space travel. Due to their low temperatures (LH2 at 20 K and LO2 at 90 K), they require special handling and procedures. General Dynamics began developing LO2 and LH2 upper stages in 1956 in the form of Centaur, these efforts were soon funded by the Department of Defense in conjunction with NASA (beginning in 1958) (Ref. 2). Meanwhile NASA also worked with McDonnell Douglas to develop the SIV-B stage for the Saturn V rocket. In the subsequent years, the engineers were able to push the Centaur to up to 9 hr of orbital lifetime and the SIV-B to up to 6 hr. Due to venting the resultant boil-off from the high heat loads through the foam insulation on the upper stages, both vehicles remained in a settled configuration throughout the flights, thus the two phases of propellant (liquid and vapor) were separated at a known location. The one exception to this were the Titan/Centaur missions, which thanks to the lower boil-off using three layers of multilayer insulation (MLI), were able to coast unsettled for up to 5.25 hr during direct geosynchronous orbit insertion missions. In the years since there has been a continuous effort to extend the life of these upper stages from hours to days or even months.

Chemical composition of matrix-embedded ternary II-VI nanocrystals derived from first- and second-order Raman spectra

NASA Astrophysics Data System (ADS)

Azhniuk, Yu. M.; Hutych, Yu. I.; Lopushansky, V. V.; Prymak, M. V.; Gomonnai, A. V.; Zahn, D. R. T.

2016-12-01

A one- and multiphonon Raman scattering study is performed for an extensive set of CdS1-xSex, Cd1-yZnyS, Cd1-yZnySe, and CdSe1-xTex nanocrystals to investigate the applicability of first- and second-order Raman spectra for the determination of the matrix-embedded ternary nanocrystal composition. For one-mode ternary systems both the LO and 2LO phonon frequencies in the Raman spectra are shown to be a good measure of the nanocrystal composition. For two-mode systems, the approaches based on the difference of the LO phonon frequencies (first-order Raman spectra) or double LO overtone and combination tone frequencies (second-order Raman spectra) as well as on the LO phonon band intensity ratios are analysed. The weak electron-phonon coupling in the II-VI nanocrystals and the polaron constant values for the nanocrystal sublattices are discussed.

Higgs boson gluon-fusion production in QCD at three loops.

PubMed

Anastasiou, Charalampos; Duhr, Claude; Dulat, Falko; Herzog, Franz; Mistlberger, Bernhard

2015-05-29

We present the cross section for the production of a Higgs boson at hadron colliders at next-to-next-to-next-to-leading order (N^{3}LO) in perturbative QCD. The calculation is based on a method to perform a series expansion of the partonic cross section around the threshold limit to an arbitrary order. We perform this expansion to sufficiently high order to obtain the value of the hadronic cross at N^{3}LO in the large top-mass limit. For renormalization and factorization scales equal to half the Higgs boson mass, the N^{3}LO corrections are of the order of +2.2%. The total scale variation at N^{3}LO is 3%, reducing the uncertainty due to missing higher order QCD corrections by a factor of 3.

Morphological transitions of brain sphingomyelin are determined by the hydration protocol: ripples re-arrange in plane, and sponge-like networks disintegrate into small vesicles.

PubMed

Meyer, H W; Bunjes, H; Ulrich, A S

1999-06-01

The phase transition of hydrated brain sphingomyelin occurs at around 35 degrees C, which is close to the physiological temperature. Freeze-fracture electron microscopy is used to characterize different gel state morphologies in terms of solid-ordered and liquid-ordered phase states, according to the occurrence of ripples and other higher-dimensional bilayer deformations. Evidently, the natural mixed-chain sphingomyelin does not assume the flat L beta, phase but instead the rippled P beta, phase, with symmetric and asymmetric ripples as well as macroripples and an egg-carton pattern, depending on the incubation conditions. An unexpected difference was observed between samples that are hydrated above and below the phase transition temperature. When the lipid is hydrated at low temperature, a sponge-like network of bilayers is formed in the gel state, next to some normal lamellae. The network loses its ripples during cold-incubation, which indicates the formation of a liquid-ordered (lo) gel phase. Ripples re-appear upon warming and the sponge-like network disintegrates spontaneously and irreversibly into small vesicles above the phase transition.

Nonlinear Analysis of the Space Shuttle Superlightweight LO2 Tank. Part 2; Behavior Under 3g End-of-Flight Loads

NASA Technical Reports Server (NTRS)

Nemeth, Michael P.; Young, Richard D.; Collins, Timothy J.; Starnes, James H.,Jr.

1998-01-01

Results of linear bifurcation and nonlinear analyses of the Space Shuttle super lightweight (SLWT) external liquid-oxygen (LO2) tank are presented for an important end-of-flight loading condition. These results illustrate an important type of response mode for thin-walled shells, that are subjected to combined mechanical and thermal loads, that may be encountered in the design of other liquid-fuel launch vehicles. Linear bifurcation analyses are presented that predict several nearly equal eigenvalues that correspond to local buckling modes in the aft dome of the LO2 tank. In contrast, the nonlinear response phenomenon is shown to consist of a short-wavelength bending deformation in the aft elliptical dome of the LO2 tank that grows in amplitude in a stable manner with increasing load. Imperfection sensitivity analyses are presented that show that the presence of several nearly equal eigenvalues does not lead to a premature general instability mode for the aft dome. For the linear bifurcation and nonlinear analyses, the results show that accurate predictions of the response of the shell generally require a large-scale, high fidelity finite-element model. Results are also presented that show that the SLWT LO2 tank can support loads in excess of approximately 1.9 times the values of the operational loads considered.

Multiscale high-order/low-order (HOLO) algorithms and applications

NASA Astrophysics Data System (ADS)

Chacón, L.; Chen, G.; Knoll, D. A.; Newman, C.; Park, H.; Taitano, W.; Willert, J. A.; Womeldorff, G.

2017-02-01

We review the state of the art in the formulation, implementation, and performance of so-called high-order/low-order (HOLO) algorithms for challenging multiscale problems. HOLO algorithms attempt to couple one or several high-complexity physical models (the high-order model, HO) with low-complexity ones (the low-order model, LO). The primary goal of HOLO algorithms is to achieve nonlinear convergence between HO and LO components while minimizing memory footprint and managing the computational complexity in a practical manner. Key to the HOLO approach is the use of the LO representations to address temporal stiffness, effectively accelerating the convergence of the HO/LO coupled system. The HOLO approach is broadly underpinned by the concept of nonlinear elimination, which enables segregation of the HO and LO components in ways that can effectively use heterogeneous architectures. The accuracy and efficiency benefits of HOLO algorithms are demonstrated with specific applications to radiation transport, gas dynamics, plasmas (both Eulerian and Lagrangian formulations), and ocean modeling. Across this broad application spectrum, HOLO algorithms achieve significant accuracy improvements at a fraction of the cost compared to conventional approaches. It follows that HOLO algorithms hold significant potential for high-fidelity system scale multiscale simulations leveraging exascale computing.

100-Lb(f) LO2/LCH4 Reaction Control Engine Technology Development for Future Space Vehicles

NASA Technical Reports Server (NTRS)

Robinson, Philip J.; Veith, Eric M.; Hurlbert, Eric A.; Jimenez, Rafael; Smith, Timothy D.

2008-01-01

The National Aeronautics and Space Administration (NASA) has identified liquid oxygen (LO2)/liquid methane (LCH4) propulsion systems as promising options for some future space vehicles. NASA issued a contract to Aerojet to develop a 100-lbf (445 N) LO2/LCH4 Reaction Control Engine (RCE) aimed at reducing the risk of utilizing a cryogenic reaction control system (RCS) on a space vehicle. Aerojet utilized innovative design solutions to develop an RCE that can ignite reliably over a broad range of inlet temperatures, perform short minimum impulse bits (MIB) at small electrical pulse widths (EPW), and produce excellent specific impulse (Isp) across a range of engine mixture ratios (MR). These design innovations also provide a start transient with a benign MR, ensuring good thrust chamber compatibility and long life. In addition, this RCE can successfully operate at MRs associated with main engines, enabling the RCE to provide emergency backup propulsion to minimize vehicle propellant load and overall system mass.

100-LBF LO2/LCH4 - Reaction Control Engine Technology Development for Future Space Vehicles

NASA Technical Reports Server (NTRS)

Robinson, Philip J.; Veith, Eric M.; Hurlbert, Eric A.; Jimenez, Rafael; Smith, Timothy D.

2008-01-01

The National Aeronautics and Space Administration (NASA) has identified liquid oxygen (LO2)/liquid methane (LCH4) propulsion systems as promising options for some future space vehicles. NASA issued a contract to Aerojet to develop a 100-lbf (445 N) LO2/LCH4 Reaction Control Engine (RCE) aimed at reducing the risk of utilizing a cryogenic reaction control system (RCS) on a space vehicle. Aerojet utilized innovative design solutions to develop an RCE that can ignite reliably over a broad range of inlet temperatures, perform short minimum impulse bits (MIB) at small electrical pulse widths (EPW), and produce excellent specific impulse (Isp) across a range of engine mixture ratios (MR). These design innovations also provide a start transient with a benign MR, ensuring good thrust chamber compatibility and long life. In addition, this RCE can successfully operate at MRs associated with main engines, enabling the RCE to provide emergency backup propulsion to minimize vehicle propellant load and overall system mass.

Propellant management for low thrust chemical propulsion systems

NASA Technical Reports Server (NTRS)

Hamlyn, K. M.; Dergance, R. H.; Aydelott, J. C.

1981-01-01

Low-thrust chemical propulsion systems (LTPS) will be required for orbital transfer of large space systems (LSS). The work reported in this paper was conducted to determine the propellant requirements, preferred propellant management technique, and propulsion system sizes for the LTPS. Propellants were liquid oxygen (LO2) combined with liquid hydrogen (LH2), liquid methane or kerosene. Thrust levels of 100, 500, and 1000 lbf were combined with 1, 4, and 8 perigee burns for transfer from low earth orbit to geosynchronous earth orbit. This matrix of systems was evaluated with a multilayer insulation (MLI) or a spray-on-foam insulation. Vehicle sizing results indicate that a toroidal tank configuration is needed for the LO2/LH2 system. Multiple perigee burns and MLI allow far superior LSS payload capability. Propellant settling, combined with a single screen device, was found to be the lightest and least complex propellant management technique.

Dynamics of the Glycophorin A Dimer in Membranes of Native-Like Composition Uncovered by Coarse-Grained Molecular Dynamics Simulations.

PubMed

Flinner, Nadine; Schleiff, Enrico

2015-01-01

Membranes are central for cells as borders to the environment or intracellular organelle definition. They are composed of and harbor different molecules like various lipid species and sterols, and they are generally crowded with proteins. The membrane system is very dynamic and components show lateral, rotational and translational diffusion. The consequence of the latter is that phase separation can occur in membranes in vivo and in vitro. It was documented that molecular dynamics simulations of an idealized plasma membrane model result in formation of membrane areas where either saturated lipids and cholesterol (liquid-ordered character, Lo) or unsaturated lipids (liquid-disordered character, Ld) were enriched. Furthermore, current discussions favor the idea that proteins are sorted into the liquid-disordered phase of model membranes, but experimental support for the behavior of isolated proteins in native membranes is sparse. To gain insight into the protein behavior we built a model of the red blood cell membrane with integrated glycophorin A dimer. The sorting and the dynamics of the dimer were subsequently explored by coarse-grained molecular dynamics simulations. In addition, we inspected the impact of lipid head groups and the presence of cholesterol within the membrane on the dynamics of the dimer within the membrane. We observed that cholesterol is important for the formation of membrane areas with Lo and Ld character. Moreover, it is an important factor for the reproduction of the dynamic behavior of the protein found in its native environment. The protein dimer was exclusively sorted into the domain of Ld character in the model red blood cell plasma membrane. Therefore, we present structural information on the glycophorin A dimer distribution in the plasma membrane in the absence of other factors like e.g. lipid anchors in a coarse grain resolution.

Multiscale high-order/low-order (HOLO) algorithms and applications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chacon, Luis; Chen, Guangye; Knoll, Dana Alan

Here, we review the state of the art in the formulation, implementation, and performance of so-called high-order/low-order (HOLO) algorithms for challenging multiscale problems. HOLO algorithms attempt to couple one or several high-complexity physical models (the high-order model, HO) with low-complexity ones (the low-order model, LO). The primary goal of HOLO algorithms is to achieve nonlinear convergence between HO and LO components while minimizing memory footprint and managing the computational complexity in a practical manner. Key to the HOLO approach is the use of the LO representations to address temporal stiffness, effectively accelerating the convergence of the HO/LO coupled system. Themore » HOLO approach is broadly underpinned by the concept of nonlinear elimination, which enables segregation of the HO and LO components in ways that can effectively use heterogeneous architectures. The accuracy and efficiency benefits of HOLO algorithms are demonstrated with specific applications to radiation transport, gas dynamics, plasmas (both Eulerian and Lagrangian formulations), and ocean modeling. Across this broad application spectrum, HOLO algorithms achieve significant accuracy improvements at a fraction of the cost compared to conventional approaches. It follows that HOLO algorithms hold significant potential for high-fidelity system scale multiscale simulations leveraging exascale computing.« less

Multiscale high-order/low-order (HOLO) algorithms and applications

DOE PAGES

Chacon, Luis; Chen, Guangye; Knoll, Dana Alan; ...

2016-11-11

Here, we review the state of the art in the formulation, implementation, and performance of so-called high-order/low-order (HOLO) algorithms for challenging multiscale problems. HOLO algorithms attempt to couple one or several high-complexity physical models (the high-order model, HO) with low-complexity ones (the low-order model, LO). The primary goal of HOLO algorithms is to achieve nonlinear convergence between HO and LO components while minimizing memory footprint and managing the computational complexity in a practical manner. Key to the HOLO approach is the use of the LO representations to address temporal stiffness, effectively accelerating the convergence of the HO/LO coupled system. Themore » HOLO approach is broadly underpinned by the concept of nonlinear elimination, which enables segregation of the HO and LO components in ways that can effectively use heterogeneous architectures. The accuracy and efficiency benefits of HOLO algorithms are demonstrated with specific applications to radiation transport, gas dynamics, plasmas (both Eulerian and Lagrangian formulations), and ocean modeling. Across this broad application spectrum, HOLO algorithms achieve significant accuracy improvements at a fraction of the cost compared to conventional approaches. It follows that HOLO algorithms hold significant potential for high-fidelity system scale multiscale simulations leveraging exascale computing.« less

Active Costorage of Cryogenic Propellants for Exploration

NASA Technical Reports Server (NTRS)

Canavan, Edgar R.; Boyle, Rob; Mustafi, Shuvo

2008-01-01

Long-term storage of cryogenic propellants is a critical requirement for NASA's effort to return to the moon. Liquid hydrogen and liquid oxygen provide the highest specific impulse of any practical chemical propulsion system, and thus provides the greatest payload mass per unit of launch mass. Future manned missions will require vehicles with the flexibility to remain in orbit for months, necessitating long-term storage of these cryogenic liquids. For decades cryogenic scientific satellites have used cryogens to cool instruments. In many cases, the lifetime of the primary cryogen tank has been extended by intercepting much of the heat incident on the tank at an intermediate-temperature shield cooled either by a second cryogen tank or a mechanical cryocooler. For an LH2/LO2 propellant system, a combination of these ideas can be used, in which the shield around the LO2 tank is attached to, and at the same temperature as, the LO2 tank, but is actively cooled so as to remove all heat impinging on the tank and shield. This configuration eliminates liquid oxygen boil-off and cuts the liquid hydrogen boil-off to a small fraction of the unshielded rate. This paper studies the concept of active costorage as a means of long-term cryogenic propellant storage. The paper describes the design impact of an active costorage system for the Crew Exploration Vehicle (CEV). This paper also compares the spacecraft level impact of the active costorage concept with a passive storage option in relation to two different scales of spacecraft that will be used for the lunar exploration effort, the CEV and the Earth Departure Stage (EDS). Spacecraft level studies are performed to investigate the impact of scaling of the costorage technologies for the different components of the Lunar Architecture and for different mission durations.

A Heat Transfer Investigation of Liquid and Two-Phase Methane

NASA Technical Reports Server (NTRS)

VanNoord, Jonathan

2010-01-01

A heat transfer investigation was conducted for liquid and two-phase methane. The tests were conducted at the NASA Glenn Research Center Heated Tube Facility (HTF) using resistively heated tube sections to simulate conditions encountered in regeneratively cooled rocket engines. This testing is part of NASA s Propulsion and Cryogenics Advanced Development (PCAD) project. Nontoxic propellants, such as liquid oxygen/liquid methane (LO2/LCH4), offer potential benefits in both performance and safety over equivalently sized hypergolic propulsion systems in spacecraft applications. Regeneratively cooled thrust chambers are one solution for high performance, robust LO2/LCH4 engines, but cooling data on methane is limited. Several test runs were conducted using three different diameter Inconel 600 tubes, with nominal inner diameters of 0.0225-, 0.054-, and 0.075-in. The mass flow rate was varied from 0.005 to 0.07 lbm/sec. As the current focus of the PCAD project is on pressure fed engines for LO2/LCH4, the average test section outlet pressures were targeted to be 200 psia or 500 psia. The heat flux was incrementally increased for each test condition while the test section wall temperatures were monitored. A maximum average heat flux of 6.2 Btu/in.2 sec was achieved and, at times, the temperatures of the test sections reached in excess of 1800 R. The primary objective of the tests was to produce heat transfer correlations for methane in the liquid and two-phase regime. For two-phase flow testing, the critical heat flux values were determined where the fluid transitions from nucleate boiling to film boiling. A secondary goal of the testing was to measure system pressure drops in the two-phase regime.

Multigroup Radiation-Hydrodynamics with a High-Order, Low-Order Method

DOE PAGES

Wollaber, Allan Benton; Park, HyeongKae; Lowrie, Robert Byron; ...

2016-12-09

Recent efforts at Los Alamos National Laboratory to develop a moment-based, scale-bridging [or high-order (HO)–low-order (LO)] algorithm for solving large varieties of the transport (kinetic) systems have shown promising results. A part of our ongoing effort is incorporating this methodology into the framework of the Eulerian Applications Project to achieve algorithmic acceleration of radiationhydrodynamics simulations in production software. By starting from the thermal radiative transfer equations with a simple material-motion correction, we derive a discretely consistent energy balance equation (LO equation). We demonstrate that the corresponding LO system for the Monte Carlo HO solver is closely related to the originalmore » LO system without material-motion corrections. We test the implementation on a radiative shock problem and show consistency between the energy densities and temperatures in the HO and LO solutions as well as agreement with the semianalytic solution. We also test the approach on a more challenging two-dimensional problem and demonstrate accuracy enhancements and algorithmic speedups. This paper extends a recent conference paper by including multigroup effects.« less

Formation of pH-sensitive cationic liposomes from a binary mixture of monoalkylated primary amine and cholesterol.

PubMed

Cui, Zhong-Kai; Bouisse, Anne; Cottenye, Nicolas; Lafleur, Michel

2012-09-25

It has been shown that mixtures of monoalkylated amphiphiles and sterols can form liquid-ordered (lo) lamellar phases. These bilayers can be extruded using conventional methods to obtain large unilamellar vesicles (LUVs) that have very low permeability and a specific response to a given stimulus. For example, pH variations can trigger the release from LUVs formed with palmitic acid and sterols. In the present work, the possibility to form non phospholipid liposomes with mixtures of stearylamine (SA) and cholesterol (Chol) was investigated. The phase behavior of these mixtures was characterized by differential scanning calorimetry, infrared, and (2)H NMR spectroscopy. It is found that this particular mixture can form a lo lamellar phase that is pH-sensitive as the system undergoes a transition from a lo phase to a solid state when pH is increased from 5.5 to 12. LUVs have been successfully extruded from equimolar SA/Chol mixtures. Release experiments as a function of time revealed the relatively low permeability of these systems. The fact that the stability of these liposomes is pH dependent implies that these LUVs display an interesting potential as new cationic carriers for pH-triggered release. This is the first report of non phospholipid liposomes with high sterol content combining an overall positive charge and pH-sensitivity.

A High-Order Low-Order Algorithm with Exponentially Convergent Monte Carlo for Thermal Radiative Transfer

DOE PAGES

Bolding, Simon R.; Cleveland, Mathew Allen; Morel, Jim E.

2016-10-21

In this paper, we have implemented a new high-order low-order (HOLO) algorithm for solving thermal radiative transfer problems. The low-order (LO) system is based on the spatial and angular moments of the transport equation and a linear-discontinuous finite-element spatial representation, producing equations similar to the standard S 2 equations. The LO solver is fully implicit in time and efficiently resolves the nonlinear temperature dependence at each time step. The high-order (HO) solver utilizes exponentially convergent Monte Carlo (ECMC) to give a globally accurate solution for the angular intensity to a fixed-source pure-absorber transport problem. This global solution is used tomore » compute consistency terms, which require the HO and LO solutions to converge toward the same solution. The use of ECMC allows for the efficient reduction of statistical noise in the Monte Carlo solution, reducing inaccuracies introduced through the LO consistency terms. Finally, we compare results with an implicit Monte Carlo code for one-dimensional gray test problems and demonstrate the efficiency of ECMC over standard Monte Carlo in this HOLO algorithm.« less

Space Transportation System (STS)-117 External Tank (ET)-124 Hail Damage Repair Assessment

NASA Technical Reports Server (NTRS)

Wilson, Timmy R.; Gentz, Steven J.; Barth, Timothy S.; Minute, Stephen A.; Flowers, Cody P.; Hamilton, David A.; Null, Cynthia H.; Schafer, Charles F.

2009-01-01

Severe thunderstorms with associated hail and high winds struck the STS-117 stack on February 26, 2007. Peak winds were recorded at 62 knots with hail sizes ranging from 0.3 inch to 0.8 inch in diameter. As a result of the storm, the North Carolina Foam Institute (NCFI) type 24-124 Thermal Protection System (TPS) foam on the liquid oxygen (LO2) ogive acreage incurred significant impact damage. The NCFI on the ET intertank and the liquid hydrogen (LH2) acreage sustained hail damage. The Polymer Development Laboratory (PDL)-1034 foam of the LO2 ice frost ramps (IFRs) and the Super-Lightweight Ablator (SLA) of the LO2 cable tray also suffered minor damage. NASA Engineering and Safety Center (NESC) was asked to assess the technical feasibility of repairing the ET TPS, the reasonableness of conducting those repairs with the vehicle in a vertical, integrated configuration at the Kennedy Space Center (KSC) Vehicle Assemble Building (VAB), and to address attendant human factors considerations including worker fatigue and the potential for error. The outcome of the assessment is recorded in this document.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chacón, L., E-mail: chacon@lanl.gov; Chen, G.; Knoll, D.A.

We review the state of the art in the formulation, implementation, and performance of so-called high-order/low-order (HOLO) algorithms for challenging multiscale problems. HOLO algorithms attempt to couple one or several high-complexity physical models (the high-order model, HO) with low-complexity ones (the low-order model, LO). The primary goal of HOLO algorithms is to achieve nonlinear convergence between HO and LO components while minimizing memory footprint and managing the computational complexity in a practical manner. Key to the HOLO approach is the use of the LO representations to address temporal stiffness, effectively accelerating the convergence of the HO/LO coupled system. The HOLOmore » approach is broadly underpinned by the concept of nonlinear elimination, which enables segregation of the HO and LO components in ways that can effectively use heterogeneous architectures. The accuracy and efficiency benefits of HOLO algorithms are demonstrated with specific applications to radiation transport, gas dynamics, plasmas (both Eulerian and Lagrangian formulations), and ocean modeling. Across this broad application spectrum, HOLO algorithms achieve significant accuracy improvements at a fraction of the cost compared to conventional approaches. It follows that HOLO algorithms hold significant potential for high-fidelity system scale multiscale simulations leveraging exascale computing.« less

Electronically Tuned Local Oscillators for the NOEMA Interferometer

NASA Astrophysics Data System (ADS)

Mattiocco, Francois; Garnier, Olivier; Maier, Doris; Navarrini, Alessandro; Serres, Patrice

2016-03-01

We present an overview of the electronically tuned local oscillator (LO) system developed at the Institut de RadioAstronomie millimetrique (IRAM) for the superconductor-insulator-superconductor (SIS) receivers of the NOrthern Extended Millimeter Array interferometer (NOEMA). We modified the frequency bands and extended the bandwidths of the LO designs developed by the National Radio Astronomy Observatory (NRAO) for the Atacama Large Millimeter Array (ALMA) project to cover the four NOEMA LO frequency ranges 82-108.3 GHz (Band 1), 138.6-171.3 GHz (Band 2), 207.7-264.4 GHz (Band 3), and 283-365 GHz (Band 4). The NOEMA LO system employs commercially available MMICs and GaAs millimeter MMICs from NRAO which are micro-assembled into active multiplied chain (AMC) and power amplifier (PA) modules. We discuss the problem of the LO spurious harmonics and of the LO signal directly multiplied by the SIS mixers that add extra noise and lead to detections of unwanted spectral lines from higher order sidebands. A waveguide filter in the LO path is used to reduce the higher order harmonics level of the LO at the output of the final frequency multiplier, thus mitigating the undesired effects and improving the system noise temperature.

Optimization and validation of high-performance liquid chromatography method for analyzing 25-desacetyl rifampicin in human urine

NASA Astrophysics Data System (ADS)

Lily; Laila, L.; Prasetyo, B. E.

2018-03-01

A selective, reproducibility, effective, sensitive, simple and fast High-Performance Liquid Chromatography (HPLC) was developed, optimized and validated to analyze 25-Desacetyl Rifampicin (25-DR) in human urine which is from tuberculosis patient. The separation was performed by HPLC Agilent Technologies with column Agilent Eclipse XDB- Ci8 and amobile phase of 65:35 v/v methanol: 0.01 M sodium phosphate buffer pH 5.2, at 254 nm and flow rate of 0.8ml/min. The mean retention time was 3.016minutes. The method was linear from 2–10μg/ml 25-DR with a correlation coefficient of 0.9978. Standard deviation, relative standard deviation and coefficient variation of 2, 6, 10μg/ml 25-DR were 0-0.0829, 03.1752, 0-0.0317%, respectively. The recovery of 5, 7, 9μg/ml25-DR was 80.8661, 91.3480 and 111.1457%, respectively. Limits of detection (LoD) and quantification (LoQ) were 0.51 and 1.7μg/ml, respectively. The method has fulfilled the validity guidelines of the International Conference on Harmonization (ICH) bioanalytical method which includes parameters of specificity, linearity, precision, accuracy, LoD, and LoQ. The developed method is suitable for pharmacokinetic analysis of various concentrations of 25-DR in human urine.

78 FR 6842 - Self-Regulatory Organizations; The NASDAQ Stock Market LLC; Order Approving a Proposed Rule...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-01-31

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Analytic Modeling of Pressurization and Cryogenic Propellant

NASA Technical Reports Server (NTRS)

Corpening, Jeremy H.

2010-01-01

An analytic model for pressurization and cryogenic propellant conditions during all mission phases of any liquid rocket based vehicle has been developed and validated. The model assumes the propellant tanks to be divided into five nodes and also implements an empirical correlation for liquid stratification if desired. The five nodes include a tank wall node exposed to ullage gas, an ullage gas node, a saturated propellant vapor node at the liquid-vapor interface, a liquid node, and a tank wall node exposed to liquid. The conservation equations of mass and energy are then applied across all the node boundaries and, with the use of perfect gas assumptions, explicit solutions for ullage and liquid conditions are derived. All fluid properties are updated real time using NIST Refprop.1 Further, mass transfer at the liquid-vapor interface is included in the form of evaporation, bulk boiling of liquid propellant, and condensation given the appropriate conditions for each. Model validation has proven highly successful against previous analytic models and various Saturn era test data and reasonably successful against more recent LH2 tank self pressurization ground test data. Finally, this model has been applied to numerous design iterations for the Altair Lunar Lander, Ares V Core Stage, and Ares V Earth Departure Stage in order to characterize Helium and autogenous pressurant requirements, propellant lost to evaporation and thermodynamic venting to maintain propellant conditions, and non-uniform tank draining in configurations utilizing multiple LH2 or LO2 propellant tanks. In conclusion, this model provides an accurate and efficient means of analyzing multiple design configurations for any cryogenic propellant tank in launch, low-acceleration coast, or in-space maneuvering and supplies the user with pressurization requirements, unusable propellants from evaporation and liquid stratification, and general ullage gas, liquid, and tank wall conditions as functions of time.

COMPARISON OF THE OCTANOL-AIR PARTITION COEFFICIENT AND LIQUID-PHASE VAPOR PRESSURE AS DESCRIPTORS FOR PARTICLE/GAS PARTITIONING USING LABORATORY AND FIELD DATA FOR PCBS AND PCNS

EPA Science Inventory

The conventional Junge-Pankow adsorption model uses the sub-cooled liquid vapor pressure (pLo) as a correlation parameter for gas/particle interactions. An alternative is the octanol-air partition coefficient (Koa) absorption model. Log-log plots of the particle-gas partition c...

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2011-06-14

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76 FR 34783 - Self-Regulatory Organizations; The NASDAQ Stock Market LLC; Notice of Filing and Immediate...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-06-14

... receive the waiver of the installation fee: 1. the new cabinet order must be placed in the CoLo Console \\4\\ during the designated period; and \\4\\ The ``CoLo Console'' is Web-based ordering tool that is utilized by...

Are Limits of Concern a useful concept to improve the environmental risk assessment of GM plants?

PubMed

Dolezel, Marion; Miklau, Marianne; Heissenberger, Andreas; Reichenbecher, Wolfram

2017-01-01

The European Food Safety Authority (EFSA) has introduced a concept for the environmental risk assessment of genetically modified (GM) plants which foresees the definition of ecological threshold values defining acceptable adverse effects of the GM plant on the environment (Limits of Concern, LoC). We analysed the LoC concept by scrutinising its feasibility with regard to important aspects of the environmental risk assessment. We then considered its relationship with protection goals, the comparative safety assessment and the stepwise testing approach. We finally discussed its usefulness for assessing long-term effects, effects on non-target organisms and species of conservation concern. The LoC concept is a possible approach to introduce ecological thresholds into environmental risk assessment in order to evaluate environmental harm. However, the concept leaves many important aspects open. Thresholds for environmental harm for protection goals need spatial and temporal differentiation from LoCs used for ERA indicators. Regionalisation of LoCs must be provided for as biodiversity levels and protection goals vary across the EU. Further guidance is needed with respect to the consequences, in case LoCs are exceeded and a link needs to be established between environmentally relevant results from the comparative safety assessment and the LoC concept. LoCs for long-term effects have to be evaluated by long-term monitoring. LoCs for non-target organisms need to be discriminated according to the species and parameters assessed. The overall LoC concept is considered useful if LoCs are further specified and differentiated. Although LoCs will finally be determined by political decisions, they should be based on scientific grounds in order to increase confidence in the conclusions on the safety of GM plants.

Low-thrust chemical propulsion system propellant expulsion and thermal conditioning study

NASA Technical Reports Server (NTRS)

Merino, F.; Wakabayashi, I.; Pleasant, R. L.; Hill, M.

1982-01-01

Thermal conditioning systems for satisfying engine net positive suction pressure (NPSP) requirements, and propellant expulsion systems for achieving propellant dump during a return-to-launch site (RTLS) abort were studied for LH2/LO2 and LCH4/LO2 upper stage propellant combinations. A state-of-the-art thermal conditioning system employing helium injection beneath the liquid surface shows the lowest weight penalty for LO2 and LCH4. A technology system incorporating a thermal subcooler (heat exchanger) for engine NPSP results in the lowest weight penalty for the LH2 tank. A preliminary design of two state-of-the-art and two new technology systems indicates a weight penalty difference too small to warrant development of a LH2 thermal subcooler. Analysis results showed that the LH2/LO2 propellant expulsion system is optimized for maximum dump line diameters, whereas the LCH4/LO2 system is optimized for minimum dump line diameter (LCH4) and maximum dump line diameter (LO2). The primary uncertainty is the accurate determination of two-phase flow rates through the dump system; experimentation is not recommended because this uncertainty is not considered significant.

Hybrid bearings for LH2 and LO2 turbopumps

NASA Technical Reports Server (NTRS)

Butner, M. F.; Lee, F. C.

1985-01-01

Hybrid combinations of hydrostatic and ball bearings can improve bearing performance for liquid hydrogen and liquid oxygen turbopumps. Analytic studies were conducted to optimize hybrid bearing designs for the SSME-type turbopump conditions. A method to empirically determine damping coefficients was devised. Four hybrid bearing configurations were designed, and three were fabricated. Six hybrid and hydrostatic-only bearing configurations will be tested for steady-state and transient performance, and quantification of damping coefficients. The initial tests were conducted with the liquid hydrogen bearing.

Liquid oxygen (LO2) propellant conditioning concept testing

NASA Technical Reports Server (NTRS)

Perry, Gretchen L. E.; Orth, Michael S.; Mehta, Gopal K.

1993-01-01

Testing of a simplified LO2 propellant conditioning concept for future expendable launch vehicles is discussed. Four different concepts are being investigated: no-bleed, low-bleed, use of a recirculation line, and He bubbling. A full-scale test article, which is a facsimile of a propellant feed duct with an attached section to simulate heat input from an LO2 turbopump, is to be tested at the Cold Flow Facility of the Marshall Space Flight Center West Test Area. Work to date includes: design and fabrication of the test article, design of the test facility and initial fabrication, development of a test matrix and test procedures, initial predictions of test output, and heat leak calibration and heat exchanger tests on the test articles.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bolding, Simon R.; Cleveland, Mathew Allen; Morel, Jim E.

In this paper, we have implemented a new high-order low-order (HOLO) algorithm for solving thermal radiative transfer problems. The low-order (LO) system is based on the spatial and angular moments of the transport equation and a linear-discontinuous finite-element spatial representation, producing equations similar to the standard S 2 equations. The LO solver is fully implicit in time and efficiently resolves the nonlinear temperature dependence at each time step. The high-order (HO) solver utilizes exponentially convergent Monte Carlo (ECMC) to give a globally accurate solution for the angular intensity to a fixed-source pure-absorber transport problem. This global solution is used tomore » compute consistency terms, which require the HO and LO solutions to converge toward the same solution. The use of ECMC allows for the efficient reduction of statistical noise in the Monte Carlo solution, reducing inaccuracies introduced through the LO consistency terms. Finally, we compare results with an implicit Monte Carlo code for one-dimensional gray test problems and demonstrate the efficiency of ECMC over standard Monte Carlo in this HOLO algorithm.« less

N3LO corrections to jet production in deep inelastic scattering using the Projection-to-Born method

NASA Astrophysics Data System (ADS)

Currie, J.; Gehrmann, T.; Glover, E. W. N.; Huss, A.; Niehues, J.; Vogt, A.

2018-05-01

Computations of higher-order QCD corrections for processes with exclusive final states require a subtraction method for real-radiation contributions. We present the first-ever generalisation of a subtraction method for third-order (N3LO) QCD corrections. The Projection-to-Born method is used to combine inclusive N3LO coefficient functions with an exclusive second-order (NNLO) calculation for a final state with an extra jet. The input requirements, advantages, and potential applications of the method are discussed, and validations at lower orders are performed. As a test case, we compute the N3LO corrections to kinematical distributions and production rates for single-jet production in deep inelastic scattering in the laboratory frame, and compare them with data from the ZEUS experiment at HERA. The corrections are small in the central rapidity region, where they stabilize the predictions to sub per-cent level. The corrections increase substantially towards forward rapidity where large logarithmic effects are expected, thereby yielding an improved description of the data in this region.

Discrete Data Qualification System and Method Comprising Noise Series Fault Detection

NASA Technical Reports Server (NTRS)

Fulton, Christopher; Wong, Edmond; Melcher, Kevin; Bickford, Randall

2013-01-01

A Sensor Data Qualification (SDQ) function has been developed that allows the onboard flight computers on NASA s launch vehicles to determine the validity of sensor data to ensure that critical safety and operational decisions are not based on faulty sensor data. This SDQ function includes a novel noise series fault detection algorithm for qualification of the output data from LO2 and LH2 low-level liquid sensors. These sensors are positioned in a launch vehicle s propellant tanks in order to detect propellant depletion during a rocket engine s boost operating phase. This detection capability can prevent the catastrophic situation where the engine operates without propellant. The output from each LO2 and LH2 low-level liquid sensor is a discrete valued signal that is expected to be in either of two states, depending on whether the sensor is immersed (wet) or exposed (dry). Conventional methods for sensor data qualification, such as threshold limit checking, are not effective for this type of signal due to its discrete binary-state nature. To address this data qualification challenge, a noise computation and evaluation method, also known as a noise fault detector, was developed to detect unreasonable statistical characteristics in the discrete data stream. The method operates on a time series of discrete data observations over a moving window of data points and performs a continuous examination of the resulting observation stream to identify the presence of anomalous characteristics. If the method determines the existence of anomalous results, the data from the sensor is disqualified for use by other monitoring or control functions.

Isolation and analysis of membrane lipids and lipid rafts in common carp (Cyprinus carpio L.).

PubMed

Brogden, Graham; Propsting, Marcus; Adamek, Mikolaj; Naim, Hassan Y; Steinhagen, Dieter

2014-03-01

Cell membranes act as an interface between the interior of the cell and the exterior environment and facilitate a range of essential functions including cell signalling, cell structure, nutrient uptake and protection. It is composed of a lipid bilayer with integrated proteins, and the inner leaflet of the lipid bilayer comprises of liquid ordered (Lo) and liquid disordered (Ld) domains. Lo microdomains, also named as lipid rafts are enriched in cholesterol, sphingomyelin and certain types of proteins, which facilitate cell signalling and nutrient uptake. Lipid rafts have been extensively researched in mammals and the presence of functional lipid rafts was recently demonstrated in goldfish, but there is currently very little knowledge about their composition and function in fish. Therefore a protocol was established for the analysis of lipid rafts and membranous lipids in common carp (Cyprinus carpio L.) tissues. Twelve lipids were identified and analysed in the Ld domain of the membrane with the most predominant lipids found in all tissues being; triglycerides, cholesterol, phosphoethanolamine and phosphatidylcholine. Four lipids were identified in lipid rafts in all tissues analysed, triglycerides (33-62%) always found in the highest concentration followed by cholesterol (24-32%), phosphatidylcholine and sphingomyelin. Isolation of lipid rafts was confirmed by identifying the presence of the lipid raft associated protein flotillin, present at higher concentrations in the detergent resistant fraction. The data provided here build a lipid library of important carp tissues as a baseline for further studies into virus entry, protein trafficking or environmental stress analysis. Copyright © 2013 Elsevier Inc. All rights reserved.

Ethanol effects on binary and ternary supported lipid bilayers with gel/fluid domains and lipid rafts.

PubMed

Marquês, Joaquim T; Viana, Ana S; De Almeida, Rodrigo F M

2011-01-01

Ethanol-lipid bilayer interactions have been a recurrent theme in membrane biophysics, due to their contribution to the understanding of membrane structure and dynamics. The main purpose of this study was to assess the interplay between membrane lateral heterogeneity and ethanol effects. This was achieved by in situ atomic force microscopy, following the changes induced by sequential ethanol additions on supported lipid bilayers formed in the absence of alcohol. Binary phospholipid mixtures with a single gel phase, dipalmitoylphosphatidylcholine (DPPC)/cholesterol, gel/fluid phase coexistence DPPC/dioleoylphosphatidylcholine (DOPC), and ternary lipid mixtures containing cholesterol, mimicking lipid rafts (DOPC/DPPC/cholesterol and DOPC/sphingomyelin/cholesterol), i.e., with liquid ordered/liquid disordered (ld/lo) phase separation, were investigated. For all compositions studied, and in two different solid supports, mica and silicon, domain formation or rearrangement accompanied by lipid bilayer thinning and expansion was observed. In the case of gel/fluid coexistence, low ethanol concentrations lead to a marked thinning of the fluid but not of the gel domains. In the case of ld/lo all the bilayer thins simultaneously by a similar extent. In both cases, only the more disordered phase expanded significantly, indicating that ethanol increases the proportion of disordered domains. Water/bilayer interfacial tension variation and freezing point depression, inducing acyl chain disordering (including opening and looping), tilting, and interdigitation, are probably the main cause for the observed changes. The results presented herein demonstrate that ethanol influences the bilayer properties according to membrane lateral organization. Copyright © 2010 Elsevier B.V. All rights reserved.

Effect of Propellant Flowrate and Purity on Carbon Deposition in LO2/Methane Gas Generators

NASA Technical Reports Server (NTRS)

Bossard, J. A.; Burkhardt, W. M.; Niiya, K. Y.; Braam, F.

1989-01-01

The generation and deposition of carbon was studied in the Carbon Deposition Program using subscale hardware with LO2/Liquid Natural Gas (LNG) and LO2/Methane propellants at low mixture ratios. The purpose of the testing was to evaluate the effect of methane purity and full scale injection density on carbon deposition. The LO2/LNG gas generator/preburner testing was performed at mixture ratios between 0.24 and 0.58 and chamber pressures from 5.8 to 9.4 MPa (840 to 1370 psia). A total of seven 200 second duration tests were performed. The LNG testing occurred at low injection densities, similar to the previous LO2/RP-1, LO2/propane, and LO2/methane testing performed on the carbon deposition program. The current LO2/methane test series occurred at an injection density factor of approximately 10 times higher than the previous testing. The high injection density LO2/methane testing was performed at mixture ratios between from 0.23 to 0.81 and chamber pressures from 6.4 to 15.2 MPa (925 to 2210 psia). A total of nine high injection density tests were performed. The testing performed demonstrated that low purity methane (LNG) did not produce any detectable change in carbon deposition when compared to pure methane. In addition, the C* performance and the combustion gas temperatures measured were similar to those obtained for pure methane. Similar results were obtained testing pure methane at higher propellant injection densities with coarse injector elements.

Dynamics of the Glycophorin A Dimer in Membranes of Native-Like Composition Uncovered by Coarse-Grained Molecular Dynamics Simulations

PubMed Central

Flinner, Nadine; Schleiff, Enrico

2015-01-01

Membranes are central for cells as borders to the environment or intracellular organelle definition. They are composed of and harbor different molecules like various lipid species and sterols, and they are generally crowded with proteins. The membrane system is very dynamic and components show lateral, rotational and translational diffusion. The consequence of the latter is that phase separation can occur in membranes in vivo and in vitro. It was documented that molecular dynamics simulations of an idealized plasma membrane model result in formation of membrane areas where either saturated lipids and cholesterol (liquid-ordered character, Lo) or unsaturated lipids (liquid-disordered character, Ld) were enriched. Furthermore, current discussions favor the idea that proteins are sorted into the liquid-disordered phase of model membranes, but experimental support for the behavior of isolated proteins in native membranes is sparse. To gain insight into the protein behavior we built a model of the red blood cell membrane with integrated glycophorin A dimer. The sorting and the dynamics of the dimer were subsequently explored by coarse-grained molecular dynamics simulations. In addition, we inspected the impact of lipid head groups and the presence of cholesterol within the membrane on the dynamics of the dimer within the membrane. We observed that cholesterol is important for the formation of membrane areas with Lo and Ld character. Moreover, it is an important factor for the reproduction of the dynamic behavior of the protein found in its native environment. The protein dimer was exclusively sorted into the domain of Ld character in the model red blood cell plasma membrane. Therefore, we present structural information on the glycophorin A dimer distribution in the plasma membrane in the absence of other factors like e.g. lipid anchors in a coarse grain resolution. PMID:26222139

Advanced space engine preliminary design. [liquid hydrogen/liquid oxygen upper stage engine for space tug application

NASA Technical Reports Server (NTRS)

Zachary, A. T.

1973-01-01

Analysis and design of an optimum LO2/LH2, combustion topping cycle, 88,964 Newtons (20,000-pound) thrust, liquid rocket engine was conducted. The design selected is well suited to high-energy, upper-stage engine applications such as the Space Tug and embodies features directed toward optimization of vehicle performance. A configuration selection was conducted based on prior Air Force Contracts, and additional criteria for optimum stage performance. Following configuration selection, analyses and design of the major components and engine systems were conducted to sufficient depth to provide layout drawings suitable for subsequent detailing. In addition, engine packaging to a common interface and a retractable nozzle concept were defined. Alternative development plans and related costs were also established. The design embodies high-performance, low-weight, low NPSH requirements (saturated propellant inlet conditions at start), idle-mode operation, and autogenous pressurization. The design is the result of the significant past and current LO2/LH2 technology efforts of the NASA centers and the Air Force, as well as company-funded programs.

Fault Detection, Isolation and Recovery (FDIR) Portable Liquid Oxygen Hardware Demonstrator

NASA Technical Reports Server (NTRS)

Oostdyk, Rebecca L.; Perotti, Jose M.

2011-01-01

The Fault Detection, Isolation and Recovery (FDIR) hardware demonstration will highlight the effort being conducted by Constellation's Ground Operations (GO) to provide the Launch Control System (LCS) with system-level health management during vehicle processing and countdown activities. A proof-of-concept demonstration of the FDIR prototype established the capability of the software to provide real-time fault detection and isolation using generated Liquid Hydrogen data. The FDIR portable testbed unit (presented here) aims to enhance FDIR by providing a dynamic simulation of Constellation subsystems that feed the FDIR software live data based on Liquid Oxygen system properties. The LO2 cryogenic ground system has key properties that are analogous to the properties of an electronic circuit. The LO2 system is modeled using electrical components and an equivalent circuit is designed on a printed circuit board to simulate the live data. The portable testbed is also be equipped with data acquisition and communication hardware to relay the measurements to the FDIR application running on a PC. This portable testbed is an ideal capability to perform FDIR software testing, troubleshooting, training among others.

Tamoxifen-loaded lecithin organogel (LO) for topical application: Development, optimization and characterization.

PubMed

Bhatia, Amit; Singh, Bhupinder; Raza, Kaisar; Wadhwa, Sheetu; Katare, Om Prakash

2013-02-28

Lecithin organogels (LOs) are semi-solid systems with immobilized organic liquid phase in 3-D network of self-assembled gelators. This paper attempts to study the various attributes of LOs, starting from selection of materials, optimization of influential components to LO specific characterization. After screening of various components (type of gelators, organic and aqueous phase) and construction of phase diagrams, a D-optimal mixture design was employed for the systematic optimization of the LO composition. The response surface plots were constructed for various response variables, viz. viscosity, gel strength, spreadability and consistency index. The optimized LO composition was searched employing overlay plots. Subsequent validation of the optimization study employing check-point formulations, located using grid search, indicated high degree of prognostic ability of the experimental design. The optimized formulation was characterized for morphology, drug content, rheology, spreadability, pH, phase transition temperatures, and physical and chemical stability. The outcomes of the study were interesting showing high dependence of LO attributes on the type and amount of phospholipid, Poloxamer™, auxillary gelators and organic solvent. The optimized LO was found to be quite stable, easily applicable and biocompatible. The findings of the study can be utilized for the development of LO systems of other drugs for the safer and effective topical delivery. Crown Copyright © 2013. Published by Elsevier B.V. All rights reserved.

Neutron matter at next-to-next-to-next-to-leading order in chiral effective field theory.

PubMed

Tews, I; Krüger, T; Hebeler, K; Schwenk, A

2013-01-18

Neutron matter presents a unique system for chiral effective field theory because all many-body forces among neutrons are predicted to next-to-next-to-next-to-leading order (N(3)LO). We present the first complete N(3)LO calculation of the neutron matter energy. This includes the subleading three-nucleon forces for the first time and all leading four-nucleon forces. We find relatively large contributions from N(3)LO three-nucleon forces. Our results provide constraints for neutron-rich matter in astrophysics with controlled theoretical uncertainties.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wollaber, Allan Benton; Park, HyeongKae; Lowrie, Robert Byron

Recent efforts at Los Alamos National Laboratory to develop a moment-based, scale-bridging [or high-order (HO)–low-order (LO)] algorithm for solving large varieties of the transport (kinetic) systems have shown promising results. A part of our ongoing effort is incorporating this methodology into the framework of the Eulerian Applications Project to achieve algorithmic acceleration of radiationhydrodynamics simulations in production software. By starting from the thermal radiative transfer equations with a simple material-motion correction, we derive a discretely consistent energy balance equation (LO equation). We demonstrate that the corresponding LO system for the Monte Carlo HO solver is closely related to the originalmore » LO system without material-motion corrections. We test the implementation on a radiative shock problem and show consistency between the energy densities and temperatures in the HO and LO solutions as well as agreement with the semianalytic solution. We also test the approach on a more challenging two-dimensional problem and demonstrate accuracy enhancements and algorithmic speedups. This paper extends a recent conference paper by including multigroup effects.« less

Design and experimental investigation of a cryogenic system for environmental test applications

NASA Astrophysics Data System (ADS)

Yan, Lutao; Li, Hong; Liu, Yue; Han, Che; Lu, Tian; Su, Yulei

2015-04-01

This paper is concerned with the design, development and performance testing of a cryogenic system for use in high cooling power instruments for ground-based environmental testing. The system provides a powerful tool for a combined environmental test that consists of high pressure and cryogenic temperatures. Typical cryogenic conditions are liquid hydrogen (LH2) and liquid oxygen (LO2), which are used in many fields. The cooling energy of liquid nitrogen (LN2) and liquid helium (LHe) is transferred to the specimen by a closed loop of helium cycle. In order to minimize the consumption of the LHe, the optimal design of heat recovery exchangers has been used in the system. The behavior of the system is discussed based on experimental data of temperature and pressure. The results show that the temperature range from room temperature to LN2 temperature can be achieved by using LN2, the pressurization process is stable and the high test pressure is maintained. Lower temperatures, below 77 K, can also be obtained with LHe cooling, the typical cooling time is 40 min from 90 K to 22 K. Stable temperatures of 22 K at the inlet of the specimen have been observed, and the system in this work can deliver to the load a cooling power of several hundred watts at a pressure of 0.58 MPa.

15(S)-HETE modulates LTB(4) production and neutrophil chemotaxis in chronic bronchitis.

PubMed

Profita, M; Sala, A; Riccobono, L; Pace, E; Paternò, A; Zarini, S; Siena, L; Mirabella, A; Bonsignore, G; Vignola, A M

2000-10-01

We evaluated the levels of 15(S)-hydroxyeicosatetraenoic acid [15(S)-HETE] and the expression of 15-lipoxygenase (15-LO) mRNA in induced sputum obtained from 10 control and 15 chronic bronchitis subjects. 15(S)-HETE was evaluated by reverse phase high-performance liquid chromatography separation followed by specific RIA. 15-LO mRNA expression was determined by primed in situ labeling. The levels of both soluble and cell-associated 15(S)-HETE resulted significantly higher in chronic bronchitis than in control subjects. The percentage of cells expressing 15-LO mRNA was significantly higher in chronic bronchitis than in control subjects (P < 0.01). Double staining for specific cell type markers and 15-LO mRNA showed macrophages and neutrophils positive for 15-LO, whereas similar staining of peripheral blood neutrophils did not show evidence for 15-LO expression, suggesting that expression of 15-LO in neutrophils takes place on migration into the airways. Because 15(S)-HETE inversely correlated with the percentage of neutrophils in sputum of chronic bronchitis subjects, we studied the effect of 15(S)-HETE on leukotriene B(4) (LTB(4)) production in vitro and evaluated the concentration of LTB(4) in induced sputum and the contribution of LTB(4) to the chemotactic activity of induced sputum samples ex vivo. The results obtained indicate that macrophages and neutrophils present within the airways of chronic bronchitis subjects express 15-LO mRNA; increased basal levels of 15(S)-HETE may contribute to modulate, through the inhibition of 5-lipoxygenase metabolites production, neutrophil infiltration and airway inflammation associated with chronic bronchitis.

Enhanced Laser-Induced Breakdown Spectroscopy By Second-Pulse Selective Wavelength Excitation

NASA Astrophysics Data System (ADS)

Vidal, F.; Chaker, M.; Goueguel, C.; Laville, S.; Loudyi, H.; Rifai, K.; Sabsabi, M.

2008-09-01

We investigate the use of a second laser with a selected wavelength to improve the limit of detection (LoD) of trace elements in the Laser-Induced Breakdown Spectroscopy (LIBS) technique. We consider the combination of LIBS with Laser-Induced Fluorescence (LIF), in which the second laser is used to excite trace elements in the plasma. The influence of the main experimental parameters on the trace elements LIF signal, namely the ablation fluence, the excitation energy, and the inter-pulse delay, was studied experimentally and a physical interpretation of the results was presented. For illustrative purpose we considered detection of Pb in brass samples and in water. The plasma was produced by a Q-switched Nd:YAG laser and then re-excited by a nanosecond optical parametric oscillator laser. We found out that the optimal conditions for our experimental set-up were obtained for relatively weak ablation fluence of 2-3 J/cm2 and inter-pulse delay of 5-10 μs. Using the LIBS-LIFS technique, a single-shot LoD for detection of lead of about 1.5 part per million (ppm) was obtained for solids and 0.5 ppm for liquids. These LoDs represent an improvement of about two orders of magnitude with respect to LIBS. We also discuss resonance-enhanced LIBS (RELIBS), in which the second laser excites the main plasma component instead of the impurities. For the set of parameters used the RELIBS, Pb signal does not differ significantly from the LIBS signal except at low ablation fluence.

Cryogenic Boil-Off Reduction System Testing

NASA Technical Reports Server (NTRS)

Plachta, David W.; Johnson, Wesley L.; Feller, Jeffrey R.

2014-01-01

Cryogenic propellants such as liquid hydrogen (LH2) and liquid oxygen (LO2) are a part of NASA's future space exploration due to the high specific impulse that can be achieved using engines suitable for moving 10's to 100's of metric tons of payload mass to destinations outside of low earth orbit. However, the low storage temperatures of LH2 and LO2 cause substantial boil-off losses for missions with durations greater than several days. The losses can be greatly reduced by incorporating high performance cryocooler technology to intercept heat load to the propellant tanks and by the integration of self-supporting multi-layer insulation. The active thermal control technology under development is the integration of the reverse turbo- Brayton cycle cryocooler to the propellant tank through a distributed cooling network of tubes coupled to a shield in the tank insulation and to the tank wall itself. Also, the self-supporting insulation technology was utilized under the shield to obtain needed tank applied LH2 performance. These elements were recently tested at NASA Glenn Research Center in a series of three tests, two that reduced LH2 boil-off and one to eliminate LO2 boil-off. This test series was conducted in a vacuum chamber that replicated the vacuum of space and the temperatures of low Earth orbit. The test results show that LH2 boil-off was reduced 60% by the cryocooler system operating at 90K and that robust LO2 zero boil-off storage, including full tank pressure control was achieved.

Kinetic Defects Induced by Melittin in Model Lipid Membranes: A Solution Atomic Force Microscopy Study.

PubMed

Pan, Jianjun; Khadka, Nawal K

2016-05-26

Quantitative characterization of membrane defects (pores) is important for elucidating the molecular basis of many membrane-active peptides. We study kinetic defects induced by melittin in vesicular and planar lipid bilayers. Fluorescence spectroscopy measurements indicate that melittin induces time-dependent calcein leakage. Solution atomic force microscopy (AFM) is used to visualize melittin-induced membrane defects. After initial equilibration, the most probable defect radius is ∼3.8 nm in 1,2-dilauroyl-sn-glycero-3-phosphocholine (DLPC) bilayers. Unexpectedly, defects become larger with longer incubation, accompanied by substantial shape transformation. The initial defect radius is ∼4.7 nm in 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) bilayers. Addition of 30 mol % cholesterol to DOPC bilayers suppresses defect kinetics, although the inhibitory impact is negated by longer incubation. Overall, the kinetic rate of defect development follows DLPC > DOPC > DOPC/cholesterol. Kinetic defects are also observed when anionic lipids are present. Based on the observation that defects can occupy as large as 40% of the bilayer surface, we propose a kinetic defect growth model. We also study the effect of melittin on the phase behavior of DOPC/egg-sphingomyelin/cholesterol bilayers. We find that melittin initially suppresses or eliminates liquid-ordered (Lo) domains; Lo domains gradually emerge and become the dominant species with longer incubation; and defects in phase-coexisting bilayers have a most probable radius of ∼5 nm and are exclusively localized in the liquid-disordered (Ld) phase. Our experimental data highlight that melittin-induced membrane defects are not static; conversely, spontaneous defect growth is intrinsically associated with membrane permeabilization exerted by melittin.

Photopolymerization of Dienoyl Lipids Creates Planar Supported Poly(lipid) Membranes with Retained Fluidity.

PubMed

Orosz, Kristina S; Jones, Ian W; Keogh, John P; Smith, Christopher M; Griffin, Kaitlyn R; Xu, Juhua; Comi, Troy J; Hall, H K; Saavedra, S Scott

2016-02-16

Polymerization of substrate-supported bilayers composed of dienoylphosphatidylcholine (PC) lipids is known to greatly enhance their chemical and mechanical stability; however, the effects of polymerization on membrane fluidity have not been investigated. Here planar supported lipid bilayers (PSLBs) composed of dienoyl PCs on glass substrates were examined to assess the degree to which UV-initiated polymerization affects lateral lipid mobility. Fluorescence recovery after photobleaching (FRAP) was used to measure the diffusion coefficients (D) and mobile fractions of rhodamine-DOPE in unpolymerized and polymerized PSLBs composed of bis-sorbyl phosphatidylcholine (bis-SorbPC), mono-sorbyl-phosphatidylcholine (mono-SorbPC), bis-dienoyl-phosphatidylcholine (bis-DenPC), and mono-dienoyl phosphatidylcholine (mono-DenPC). Polymerization was performed in both the Lα and Lβ phase for each lipid. In all cases, polymerization reduced membrane fluidity; however, measurable lateral diffusion was retained which is attributed to a low degree of polymerization. The D values for sorbyl lipids were less than those of the denoyl lipids; this may be a consequence of the distal location of polymerizable group in the sorbyl lipids which may facilitate interleaflet bonding. The D values measured after polymerization were 0.1-0.8 of those measured before polymerization, a range that corresponds to fluidity intermediate between that of a Lα phase and a Lβ phase. This D range is comparable to ratios of D values reported for liquid-disordered (Ld) and liquid-ordered (Lo) lipid phases and indicates that the effect of UV polymerization on lateral diffusion in a dienoyl PSLB is similar to the transition from a Ld phase to a Lo phase. The partial retention of fluidity in UV-polymerized PSLBs, their enhanced stability, and the activity of incorporated transmembrane proteins and peptides is discussed.

Photopolymerization of dienoyl lipids creates planar supported poly(lipid) membranes with retained fluidity

PubMed Central

Orosz, Kristina S.; Jones, Ian W.; Keogh, John P.; Smith, Christopher M.; Griffin, Kaitlyn R.; Xu, Juhua; Comi, Troy J.; Hall, H. K.

2016-01-01

Polymerization of substrate-supported bilayers composed of dienoyl phosphatidylcholine (PC) lipids is known to greatly enhance their chemical and mechanical stability, however the effects of polymerization on membrane fluidity have not been investigated. Here planar supported lipid bilayers (PSLBs) composed of dienoyl PCs on glass substrates were examined to assess the degree to which UV-initiated polymerization affects lateral lipid mobility. Fluorescence recovery after photobleaching (FRAP) was used to measure the diffusion coefficients (D) and mobile fractions of rhodamine-DOPE in unpolymerized and polymerized PSLBs composed of bis-sorbyl phosphatidylcholine (bis-SorbPC), mono-sorbyl phosphatidylcholine (mono-SorbPC), bis-dienoyl phosphatidylcholine (bis-DenPC) and mono-dienoyl phosphatidylcholine (mono-DenPC). Polymerization was performed in both the Lα and Lβ phase for each lipid. In all cases, polymerization reduced membrane fluidity, however measurable lateral diffusion was retained which is attributed to a low degree of polymerization. The D values for sorbyl lipids were less than those of the denoyl lipids; this may be a consequence of the distal location of polymerizable group in the sorbyl lipids which may facilitate inter-leaflet bonding. The D values measured after polymerization were 0.1 to 0.8 of those measured before polymerization, a range that corresponds to fluidity intermediate between that of a Lα phase and a Lβ phase. This D range is comparable to ratios of D values reported for liquid-disordered (Ld) and liquid-ordered (Lo) lipid phases, and indicates that the effect of UV polymerization on lateral diffusion in a dienoyl PSLB is similar to the transition from a Ld phase to a Lo phase. The partial retention of fluidity in UV polymerized PSLBs, their enhanced stability, and the activity of incorporated transmembrane proteins and peptides is discussed. PMID:26794208

Determination of cocaine and its derivatives in hair samples by liquid phase microextraction (LPME) and gas chromatography-mass spectrometry (GC-MS).

PubMed

Pego, A M F; Roveri, F L; Kuninari, R Y; Leyton, V; Miziara, I D; Yonamine, M

2017-05-01

Hair testing is a recognized approach when it comes to accessing historical drug use. According to the World Drug Report of United Nations Office on Drugs and Crime (UNODC) 2015, Brazil is the largest cocaine (COC) market in South America. New analytical methodologies to detect crack/cocaine analytes in hair samples are highly desirable. Here, a method consisting of a liquid-phase microextraction (LPME) as a clean-up step, followed by gas chromatography-mass spectrometry (GC-MS) analysis has been proposed. The new validated method consisted of a washing step; an overnight incubation with methanol and a quick derivatization with butylchloroformate. Once derivatized, the samples were then submitted to the LPME procedure. Limits of detection (LoD) and quantitation (LoQ) obtained were of 0.1 and 0.5ng/mg for COC 0.4 and 0.5ng/mg for anhydroecgonine methyl ester (AEME); 0.03 and 0.05 for cocaethylene (CE), respectively and 0.05ng/mg for both LoD and LoQ for benzoylecgonine (BZE). All calibration curves were linear over the scope applied, from LoQ up to 20ng/mg, with a r 2 >0.99. Precision and accuracy assays showed acceptable %RSD values, according to international guidelines. Twelve postmortem head hair samples stemming from the Institute of Legal Medicine of Sao Paulo (IML-SP) have been analyzed, from which seven have shown to be positive for COC (0.75->20ng/mg) and BZE (0.1->20ng/mg). Apart from COC's main metabolite, four samples were also positive for CE (0.1-3.9ng/mg) and three samples for AEME (0.5-4.9ng/mg). To conclude, the LPME technique together with GC-MS analysis have shown promising results and were able to meet the demand of the laboratory of analyzing postmortem hair samples to look for all four analytes. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Third order intermodulation distortion in HTS Josephson Junction downconverter at 12GHz

DOE Office of Scientific and Technical Information (OSTI.GOV)

Suzuki, Katsumi; Hayashi, Kunihiko; Fujimoto, Manabu

1994-12-31

Here the authors first report on the microwave characteristics of the third order intermodulation distortion(IMD3) in High-Tc Superconductor (HTS) Josephson Junction (JJ) Downconverter at 12GHz. They have successfully developed high quality nonlinear YBCO microbridge Josephson junctions for such an active MMIC as a mixer with RF, LO, IF and bias filters, which have been fabricated on (100) MgO substrates with 20mm x 20mm x 0.5mm dimensions. The minimum conversion loss of the JJ mixer is 11 dB at very small local microwave input power LO= {minus}20dBm which is two order less than Schottky diode mixer. Consequently, this small optimum LOmore » power gives the small RF input power at which the output IF power of the YBCO mixer saturates. Two-tone third-order intercept point(IP3) performance is a significantly important figure of merit typically used to define linearity of devices and circuits. The RF input power = {minus}15dBm at the IP3 point is obtained for the YBCO mixer at 15K and LO = 10.935GHz with {minus}22dBm. The have successfully measured the dependence of IMD3 on temperature, bias current and LO power.« less

Novel determination of polychlorinated naphthalenes in water by liquid chromatography-mass spectrometry with atmospheric pressure photoionization.

PubMed

Moukas, Athanasios I; Thomaidis, Nikolaos S; Calokerinos, Antony C

2016-01-01

This study presents the development, optimization, and validation of a novel method for the determination of polychlorinated naphthalenes (PCNs) by liquid chromatography-atmospheric pressure photoionization (APPI), using toluene as dopant. The mass spectra of PCN 52, 54, 66, 67, 73, and 75 were recorded in negative ionization. The base ions corresponded to [M-Cl+O](-), where M is the analyte molecule. A strategy, which includes designs of experiments, for the development, the evaluation, and the optimization of the LC-APPI-MS/MS methods is also described. Finally, a highly sensitive method with low instrumental limits of detection (LoDs), ranging from 0.8 pg for PCN 75 to 16 pg for PCN 54 on column, was validated. A Thermo Hypersil Green PAH (100 mm × 2.1 mm, 3 μm) column was used with acetonitrile/water/methanol as mobile phase. The method was applied for the determination of the selected PCNs in surface and tap water samples. A simple liquid-liquid extraction method for the extraction of PCNs from water samples was used. Method LoQs ranged from 29 ng L(-1), for PCN 73, to 63 ng L(-1), for PCN 54, and the recoveries ranged from 97 to 99%, for all congeners. This is the first LC-APPI-MS/MS method for the determination of PCNs in water samples.

Preferential Generation of 15-HETE-PE Induced by IL-13 Regulates Goblet Cell Differentiation in Human Airway Epithelial Cells.

PubMed

Zhao, Jinming; Minami, Yoshinori; Etling, Emily; Coleman, John M; Lauder, Sarah N; Tyrrell, Victoria; Aldrovandi, Maceler; O'Donnell, Valerie; Claesson, Hans-Erik; Kagan, Valerian; Wenzel, Sally

2017-12-01

Type 2-associated goblet cell hyperplasia and mucus hypersecretion are well known features of asthma. 15-Lipoxygenase-1 (15LO1) is induced by the type 2 cytokine IL-13 in human airway epithelial cells (HAECs) in vitro and is increased in fresh asthmatic HAECs ex vivo. 15LO1 generates a variety of products, including 15-hydroxyeicosatetraenoic acid (15-HETE), 15-HETE-phosphatidylethanolamine (15-HETE-PE), and 13-hydroxyoctadecadienoic acid (13-HODE). In this study, we investigated the 15LO1 metabolite profile at baseline and after IL-13 treatment, as well as its influence on goblet cell differentiation in HAECs. Primary HAECs obtained from bronchial brushings of asthmatic and healthy subjects were cultured under air-liquid interface culture supplemented with arachidonic acid and linoleic acid (10 μM each) and exposed to IL-13 for 7 days. Short interfering RNA transfection and 15LO1 inhibition were applied to suppress 15LO1 expression and activity. IL-13 stimulation induced expression of 15LO1 and preferentially generated 15-HETE-PE in vitro, both of which persisted after removal of IL-13. 15LO1 inhibition (by short interfering RNA and chemical inhibitor) decreased IL-13-induced forkhead box protein A3 (FOXA3) expression and enhanced FOXA2 expression. These changes were associated with reductions in both mucin 5AC and periostin. Exogenous 15-HETE-PE stimulation (alone) recapitulated IL-13-induced FOXA3, mucin 5AC, and periostin expression. The results of this study confirm the central importance of 15LO1 and its primary product, 15-HETE-PE, for epithelial cell remodeling in HAECs.

How Lipid Membranes Affect Pore Forming Toxin Activity.

PubMed

Rojko, Nejc; Anderluh, Gregor

2015-12-15

Pore forming toxins (PFTs) evolved to permeate the plasma membrane of target cells. This is achieved in a multistep mechanism that usually involves binding of soluble protein monomer to the lipid membrane, oligomerization at the plane of the membrane, and insertion of part of the polypeptide chain across the lipid membrane to form a conductive channel. Introduced pores allow uncontrolled transport of solutes across the membrane, inflicting damage to the target cell. PFTs are usually studied from the perspective of structure-function relationships, often neglecting the important role of the bulk membrane properties on the PFT mechanism of action. In this Account, we discuss how membrane lateral heterogeneity, thickness, and fluidity influence the pore forming process of PFTs. In general, lipid molecules are more accessible for binding in fluid membranes due to steric reasons. When PFT specifically binds ordered domains, it usually recognizes a specific lipid distribution pattern, like sphingomyelin (SM) clusters or SM/cholesterol complexes, and not individual lipid species. Lipid domains were also suggested to act as an additional concentration platform facilitating PFT oligomerization, but this is yet to be shown. The last stage in PFT action is the insertion of the transmembrane segment across the membranes to build the transmembrane pore walls. Conformational changes are a spontaneous process, and sufficient free energy has to be available for efficient membrane penetration. Therefore, fluid bilayers are permeabilized more readily in comparison to highly ordered and thicker liquid ordered lipid phase (Lo). Energetically more costly insertion into the Lo phase can be driven by the hydrophobic mismatch between the thinner liquid disordered phase (Ld) and large protein complexes, which are unable to tilt like single transmembrane segments. In the case of proteolipid pores, membrane properties can directly modulate pore size, stability, and even selectivity. Finally, events associated with pore formation can modulate properties of the lipid membrane and affect its organization. Model membranes do not necessarily reproduce the physicochemical properties of the native cellular membrane, and caution is needed when transferring results from model to native lipid membranes. In this context, the utilization of novel approaches that enable studying PFTs on living cells at a single molecule level should reveal complex protein-lipid membrane interactions in greater detail.

Crystallization and melting properties of mixtures of milk fat stearin and omega-3 rich oils.

PubMed

Li, Bing-Zheng; Truong, Tuyen; Bhandari, Bhesh

2017-03-01

Solid milk fat stearin (S 25 ) can be a promising oxidation retarder due to its capacity to entrap liquid oils, especially for incorporating omega-3 (ω-3) rich oils into dairy products. Thermal properties of S 25 /ω-3 rich oil mixtures are necessary for such application. The effects of S 25 on the crystallization and melting behaviours of ω-3 rich oils, namely fish oil (FO), linseed oil (LO) and krill oil (KO), were investigated by differential scanning calorimetry (DSC). Thermograms showed that with S 25 concentration increasing, transitions of FO and LO shifted to lower and largely to higher temperatures, respectively, while crystallization temperature of KO slightly decreased. Negative, positive and low values of interaction enthalpy (ΔH int ) suggested the adverse, beneficial and limited effect of S 25 on the crystallization of S 25 /FO, S 25 /LO and S 25 /KO mixtures, respectively. LO could have the best oxidative stability upon the addition of S 25 since their interactions facilitated earlier and stronger crystallization. Copyright © 2016 Elsevier Ltd. All rights reserved.

[Comparison of the results of long term oxygen therapy in patients treated sequentially using stationary or a portable source of oxygen].

PubMed

Czajkowska-Malinowska, Małgorzata; Połtyn, Beata; Ciesielska, Anna; Kruża, Katarzyna; Jesionka, Paweł

2012-01-01

In long term oxygen therapy (LTOT) two oxygen sources are used, i.e. the stationary oxygen concentrator (OC) and portable liquid oxygen (LO). Polish NHS reimburses stationary oxygen sources only. The aim of this study was to compare the effect of change from OC into LO in patients treated using LTOT. The study involved 30 patients qualified to LTOT. The degree of dyspnoea intensity, (MRC, Borg scale), exercise tolerance (6MWT), fitness, daily use of oxygen therapy, red blood count, lung function, number of exacerbations as well as health related quality of life (SGRQ) were assessed before introduction of LTOT, after 6 months of oxygen therapy using OC and after 6 months from change into LO. During first 6 months RBC decreased from 5.4 to 5.1 (p < 0.0001), HTC from 50.1% to 47.8% (p < 0.0001), 6MWD increased from 337.7 to 378.7 m (p < 0.0001), SGRQ score improved from 72.1 points to 64.4 points (p < 0.0001). Treatment with LO resulted in further improvement in studied parameters: RBC decreased from 5.1 to 4.8 (p < 0.0001), HTC from 47.8% to 44.3% (p < 0.0001), 6MWD increased from 378.7 m to 413 m (p < 0.0001), SGRQ score improved from 64.4 points to 54.9 points (p < 0.0001). Significant increase in daily oxygen breathing hours from 13.7 to 18.9 (p < 0.0001) was also observed. Use of liquid oxygen enables oxygen therapy at home and during ambulation and increases oxygen breathing hours, thus improving red blood count, exercise capacity and health related quality of life.

Zero boil-off system testing

NASA Astrophysics Data System (ADS)

Plachta, D. W.; Johnson, W. L.; Feller, J. R.

2016-03-01

Cryogenic propellants such as liquid hydrogen (LH2) and liquid oxygen (LO2) are a part of NASA's future space exploration plans due to their high specific impulse for rocket motors of upper stages. However, the low storage temperatures of LH2 and LO2 cause substantial boil-off losses for long duration missions. These losses can be eliminated by incorporating high performance cryocooler technology to intercept heat load to the propellant tanks and modulating the cryocooler temperature to control tank pressure. The technology being developed by NASA is the reverse turbo-Brayton cycle cryocooler and its integration to the propellant tank through a distributed cooling tubing network coupled to the tank wall. This configuration was recently tested at NASA Glenn Research Center in a vacuum chamber and cryoshroud that simulated the essential thermal aspects of low Earth orbit, its vacuum and temperature. This test series established that the active cooling system integrated with the propellant tank eliminated boil-off and robustly controlled tank pressure.

Zero Boil-Off System Testing

NASA Technical Reports Server (NTRS)

Plachta, D. W.; Johnson, W. L.; Feller, J. R.

2015-01-01

Cryogenic propellants such as liquid hydrogen (LH2) and liquid oxygen (LO2) are a part of NASA's future space exploration plans due to their high specific impulse for rocket motors of upper stages. However, the low storage temperatures of LH2 and LO2 cause substantial boil-off losses for long duration missions. These losses can be eliminated by incorporating high performance cryocooler technology to intercept heat load to the propellant tanks and modulating the cryocooler temperature to control tank pressure. The technology being developed by NASA is the reverse turbo-Brayton cycle cryocooler and its integration to the propellant tank through a distributed cooling tubing network coupled to the tank wall. This configuration was recently tested at NASA Glenn Research Center in a vacuum chamber and cryoshroud that simulated the essential thermal aspects of low Earth orbit, its vacuum and temperature. This test series established that the active cooling system integrated with the propellant tank eliminated boil-off and robustly controlled tank pressure.

A cislunar transportation system fuelled by lunar resources

NASA Astrophysics Data System (ADS)

Sowers, G. F.

2016-11-01

A transportation system for a self sustaining economy in cislunar space is discussed. The system is based on liquid oxygen (LO2), liquid hydrogen (LH2) propulsion whose fuels are derived from ice mined at the polar regions of the Moon. The elements of the transportation system consist of the Advanced Cryogenic Evolved Stage (ACES) and the XEUS lander, both being developed by United Launch Alliance (ULA). The main propulsion elements and structures are common between ACES and XEUS. Both stages are fully reusable with refueling of their LO2/LH2 propellants. Utilization of lunar sourced propellants has the potential to dramatically lower the cost of transportation within the cislunar environs. These lower costs dramatically lower the barriers to entry of a number of promising cislunar based activities including space solar power. One early application of the architecture is providing lunar sourced propellant to refuel ACES for traditional spacecraft deployment missions. The business case for this application provides an economic framework for a potential lunar water mining operation.

Filterless frequency-octupling mm-wave generation by cascading Sagnac loop and DPMZM

NASA Astrophysics Data System (ADS)

Zhang, Wu; Wen, Aijun; Gao, Yongsheng; Shang, Shuo; Zheng, Hanxiao; He, Hongye

2017-12-01

In this paper, a filterless photonic frequency-octupling scheme is presented. It is implemented by cascading a Sagnac loop with an intensity modulator (IM) in it and a dual-parallel Mach-Zehnder modulator (DPMZM) in series. The Sagnac loop is used to get the ±2nd-order sidebands of LO signal. The following DPMZM is utilized to obtain the ±4th-order sidebands. By photo-detecting the ±4th-order sidebands, mm-wave signal with the eightfold frequency of LO signal can be obtained. The scheme is verified by experiments, and a 32-GHz mm-wave signal is produced with the assistance of a 4-GHz LO signal. A 20-dB optical sideband suppression ratio (OSSR) and a 17-dB electrical spurious suppression ratio (ESSR) are realized, and no extra deterioration of phase noise is observed. Besides, the verification of the frequency tunability is implemented in the experiment.

Considerations on the calibration of small thermoluminescent dosimeters used for measurement of beta particle absorbed doses in liquid environments.

PubMed

Demidecki, A J; Williams, L E; Wong, J Y; Wessels, B W; Yorke, E D; Strandh, M; Strand, S E

1993-01-01

An investigation has been carried out on the factors which affect the absolute calibration of thermoluminescent dosimeters (TLDs) used in beta particle absorbed dose evaluations. Four effects on light output (LO) were considered: decay of detector sensitivity with time, finite TLD volume, dose linearity, and energy dependence. Most important of these was the decay of LO with time in culture medium, muscle tissue, and gels. This permanent loss of sensitivity was as large as an order of magnitude over a 21-day interval for the nominally 20-microns-thick disc-shaped CaSO4(Dy) TLDs in gel. Associated leaching of the dosimeter crystals out of the Teflon matrix was observed using scanning electron microscopy. Large channels leading from the outside environment into the TLDs were identified using SEM images. A possibility of batch dependence of fading was indicated. The second most important effect was the apparent reduction of light output due to finite size and increased specific gravity of the dosimeter (volume effect). We estimated this term by calculations as 10% in standard "mini" rods for beta particles from 90Y, but nearly a factor of 3 for 131I beta particles in the same geometry. No significant nonlinearity of the log (light output) with log (absorbed dose) over the range 0.05-20.00 Gy was discovered. Energy dependence of the LO was found to be not detectable, within measurement errors, over the range of 0.60-6.0 MeV mean energy electrons. With careful understanding of these effects, calibration via gel phantom would appear to be an acceptable strategy for mini TLDs used in beta absorbed dose evaluations in media.(ABSTRACT TRUNCATED AT 250 WORDS)

From Localized Scleroderma to Systemic Sclerosis: Coexistence or Possible Evolution.

PubMed

Dilia, Giuggioli; Michele, Colaci; Emanuele, Cocchiara; Amelia, Spinella; Federica, Lumetti; Clodoveo, Ferri

2018-01-01

Systemic sclerosis (SSc) and localized scleroderma (LoS) are two different diseases that may share some features. We evaluated the relationship between SSc and LoS in our case series of SSc patients. We analysed the clinical records of 330 SSc patients, in order to find the eventual occurrence of both the two diseases. Eight (2.4%) female patients presented both the two diagnoses in their clinical histories. Six developed LoS prior to SSc; in 4/6 cases, the presence of autoantibodies was observed before SSc diagnosis. Overall, the median time interval between LoS and SSc diagnosis was 18 (range 0-156) months. LoS and SSc are two distinct clinical entities that may coexist. Moreover, as anecdotally reported in pediatric populations, we suggested the possible development of SSc in adult patients with LoS, particularly in presence of Raynaud's phenomenon or antinuclear antibodies before the SSc onset.

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Topological Fulde-Ferrell and Larkin-Ovchinnikov states in spin-orbit-coupled lattice system

NASA Astrophysics Data System (ADS)

Guo, Yao-Wu; Chen, Yan

2018-04-01

The spin-orbit coupled lattice system under Zeeman fields provides an ideal platform to realize exotic pairing states. Notable examples range from the topological superfluid/superconducting (tSC) state, which is gapped in the bulk but metallic at the edge, to the Fulde-Ferrell (FF) state (having a phase-modulated order parameter with a uniform amplitude) and the Larkin-Ovchinnikov (LO) state (having a spatially varying order parameter amplitude). Here, we show that the topological FF state with Chern number ( C = -1) (tFF1) and topological LO state with C= 2 (tLO2) can be stabilized in Rashba spin-orbit coupled lattice systems in the presence of both in-plane and out-of-plane Zeeman fields. Besides the inhomogeneous tSC states, in the presence of a weak in-plane Zeeman field, two topological BCS phases may emerge with C = -1 (tBCS1) far from half filling and C = 2 (tBCS2) near half filling. We show intriguing effects such as different spatial profiles of order parameters for FF and LO states, the topological evolution among inhomogeneous tSC states, and different non-trivial Chern numbers for the tFF1 and tLO1,2 states, which are peculiar to the lattice system. Global phase diagrams for various topological phases are presented for both half-filling and doped cases. The edge states as well as local density of states spectra are calculated for tSC states in a 2D strip.

Development of horn antenna mixer array with internal local oscillator module for microwave imaging diagnostics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kuwahara, D., E-mail: dkuwahar@cc.tuat.ac.jp; Ito, N.; Nagayama, Y.

A new antenna array is proposed in order to improve the sensitivity and complexity of microwave imaging diagnostics systems such as a microwave imaging reflectometry, a microwave imaging interferometer, and an electron cyclotron emission imaging. The antenna array consists of five elements: a horn antenna, a waveguide-to-microstrip line transition, a mixer, a local oscillation (LO) module, and an intermediate frequency amplifier. By using an LO module, the LO optics can be removed, and the supplied LO power to each element can be equalized. We report details of the antenna array and characteristics of a prototype antenna array.

Development of horn antenna mixer array with internal local oscillator module for microwave imaging diagnostics.

PubMed

Kuwahara, D; Ito, N; Nagayama, Y; Yoshinaga, T; Yamaguchi, S; Yoshikawa, M; Kohagura, J; Sugito, S; Kogi, Y; Mase, A

2014-11-01

A new antenna array is proposed in order to improve the sensitivity and complexity of microwave imaging diagnostics systems such as a microwave imaging reflectometry, a microwave imaging interferometer, and an electron cyclotron emission imaging. The antenna array consists of five elements: a horn antenna, a waveguide-to-microstrip line transition, a mixer, a local oscillation (LO) module, and an intermediate frequency amplifier. By using an LO module, the LO optics can be removed, and the supplied LO power to each element can be equalized. We report details of the antenna array and characteristics of a prototype antenna array.

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Hot-Fire Testing of 100 LB(sub F) LOX/LCH4 Reaction Control Engine at Altitude Conditions

NASA Technical Reports Server (NTRS)

Marshall, William M.; Kleinhenz, Julie E.

2010-01-01

Liquid oxygen/liquid methane (LO2/LCH4 ) has recently been viewed as a potential green propulsion system for both the Altair ascent main engine (AME) and reaction control system (RCS). The Propulsion and Cryogenic Advanced Development Project (PCAD) has been tasked by NASA to develop these green propellant systems to enable safe and cost effective exploration missions. However, experience with LO2/LCH4 as a propellant combination is limited, so testing of these systems is critical to demonstrating reliable ignition and performance. A test program of a 100 lb f reaction control engine (RCE) is underway at the Altitude Combustion Stand (ACS) of the NASA Glenn Research Center, with a focus on conducting tests at altitude conditions. These tests include a unique propellant conditioning feed system (PCFS) which allows for the inlet conditions of the propellant to be varied to test warm to subcooled liquid propellant temperatures. Engine performance, including thrust, c* and vacuum specific impulse (I(sub sp,vac)) will be presented as a function of propellant temperature conditions. In general, the engine performed as expected, with higher performance at warmer propellant temperatures but better efficiency at lower propellant temperatures. Mixture ratio effects were inconclusive within the uncertainty bands of data, but qualitatively showed higher performance at lower ratios.

Liquid hydrogen and liquid oxygen feedline passive recirculation analysis

NASA Astrophysics Data System (ADS)

Holt, Kimberly Ann; Cleary, Nicole L.; Nichols, Andrew J.; Perry, Gretchen L. E.

The primary goal of the National Launch System (NLS) program was to design an operationally efficient, highly reliable vehicle with minimal recurring launch costs. To achieve this goal, trade studies of key main propulsion subsystems were performed to specify vehicle design requirements. These requirements include the use of passive recirculation to thermally condition the liquid hydrogen (LH2) and liquid oxygen (LO2) propellant feed systems and Space Transportation Main Engine (STME) fuel pumps. Rockwell International (RI) proposed a joint independent research and development (JIRAD) program with Marshall Space Flight Center (MSFC) to study the LH2 feed system passive recirculation concept. The testing was started in July 1992 and completed in November 1992. Vertical and sloped feedline designs were used. An engine simulator was attached at the bottom of the feedline. This simulator had strip heaters that were set to equal the corresponding heat input from different engines. A computer program is currently being used to analyze the passive recirculation concept in the LH2 vertical feedline tests. Four tests, where the heater setting is the independent variable, were chosen. While the JIRAD with RI was underway, General Dynamics Space Systems (GDSS) proposed a JIRAD with MSFC to explore passive recirculation in the LO2 feed system. Liquid nitrogen (LN2) is being used instead of LO2 for safety and economic concerns. To date, three sets of calibration tests have been completed on the sloped LN2 test article. The environmental heat was calculated from the calibration tests in which the strip heaters were turned off. During the LH2 testing, the environmental heat was assumed to be constant. Therefore, the total heat was equal to the environmental heat flux plus the heater input. However, the first two sets of LN2 calibration tests have shown that the environmental heat flux varies with heater input. A Systems Improved Numerical Differencing Analyzer and Fluid Integrator (SINDA/FLUINT) model is currently being built to determine if this variation in environmental heat is due to a change in the wall temperature.

Analyzing the Fierz rearrangement freedom for local chiral two-nucleon potentials

NASA Astrophysics Data System (ADS)

Huth, L.; Tews, I.; Lynn, J. E.; Schwenk, A.

2017-11-01

Chiral effective field theory is a framework to derive systematic nuclear interactions. It is based on the symmetries of quantum chromodynamics and includes long-range pion physics explicitly, while shorter-range physics is expanded in a general operator basis. The number of low-energy couplings at a particular order in the expansion can be reduced by exploiting the fact that nucleons are fermions and therefore obey the Pauli exclusion principle. The antisymmetry permits the selection of a subset of the allowed contact operators at a given order. When local regulators are used for these short-range interactions, however, this "Fierz rearrangement freedom" is violated. In this paper, we investigate the impact of this violation at leading order (LO) in the chiral expansion. We construct LO and next-to-leading order (NLO) potentials for all possible LO-operator pairs and study their reproduction of phase shifts, the 4He ground-state energy, and the neutron-matter energy at different densities. We demonstrate that the Fierz rearrangement freedom is partially restored at NLO where subleading contact interactions enter. We also discuss implications for local chiral three-nucleon interactions.

78 FR 61429 - Self-Regulatory Organizations; The NASDAQ Stock Market LLC; Notice of Filing and Immediate...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-10-03

... cabinets ordered by users using the Co-Lo Console \\4\\ on or after October 1, 2013 through December 31, 2013... No. 68624 (Jan. 1, 2013), 78 FR 3945 (Jan. 17, 2013). \\4\\ The ``Co-Lo Console'' is NASDAQ's Web-based...

Summary of LO2/Ethanol OMS/RCS Technology and Advanced Development 99-2744

NASA Technical Reports Server (NTRS)

Curtis, Leslie A.; Hurlbert, Eric A.

1999-01-01

NASA is pursuing non-toxic propellant technologies applicable to RLV and Space Shuttle orbital maneuvering system (OMS) and reaction control system (RCS). The primary objectives of making advancements in an OMS/RCS system are improved safety, reliability, and reduced operations and maintenance cost, while meeting basic operational and performance requirements. An OMS/RCS has a high degree of direct interaction with the vehicle and crew and requires subsystem and components that are compatible with integration into the vehicle with regard to external mold-line, power, and thermal control. In July 1997, a Phase I effort for the technology and advanced development of an upgrade of the space shuttle was conducted to define the system architecture, propellant tank, feed system, RCS thrusters, and OMS engine. Phase I of the project ran from July 1997 to October 1998. Phase II is currently being planned for the development and test of full-scale prototype of the system in 1999 and 2000. The choice of pressure-fed liquid oxygen (LO2) and ethanol is the result of numerous trade studies conducted from 1980 to 1996. Liquid oxygen and ethanol are clean burning, high-density propellants that provide a high degree of commonality with other spacecraft subsystems including life support, power, and thermal control, and with future human exploration and development of space missions. The key to this pressure-fed system is the use of subcooled liquid oxygen at 350 psia. In this approach, there is 80 degrees R of subcooling, which means that boil-off will not occur until the temperature has risen 80 R. The sub-cooling results naturally from loading propellants at 163 R, which is the saturation temperature at 14.7 psia, and then pressurizing to 350 psia on the launch pad. Thermal insulation and conditioning techniques are then used to limit the LO2 temperature to 185 R maximum, and maintain the sub-cooling. The other key is the wide temperature range of ethanol, -173 F to +300 F, which can provide heat to gasify liquid oxygen or provide a good coolant.

Effect of membrane microheterogeneity and domain size on fluorescence resonance energy transfer.

PubMed

Towles, Kevin B; Brown, Angela C; Wrenn, Steven P; Dan, Nily

2007-07-15

Studies of multicomponent membranes suggest lateral inhomogeneity in the form of membrane domains, but the size of small (nanoscale) domains in situ cannot be determined with current techniques. In this article, we present a model that enables extraction of membrane domain size from time-resolved fluorescence resonance energy transfer (FRET) data. We expand upon a classic approach to the infinite phase separation limit and formulate a model that accounts for the presence of disklike domains of finite dimensions within a two-dimensional infinite planar bilayer. The model was tested against off-lattice Monte Carlo calculations of a model membrane in the liquid-disordered (l(d)) and liquid-ordered (l(o)) coexistence regime. Simulated domain size was varied from 5 to 50 nm, and two fluorophores, preferentially partitioning into opposite phases, were randomly mixed to obtain the simulated time-resolved FRET data. The Monte Carlo data show clear differences in the efficiency of energy transfer as a function of domain size. The model fit of the data yielded good agreement for the domain size, especially in cases where the domain diameter is <20 nm. Thus, data analysis using the proposed model enables measurement of nanoscale membrane domains using time-resolved FRET.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zeno, Wade F.; Johnson, Kaitlin E.; Sasaki, Darryl Y.

We use fluorescence microscopy to examine the dynamics of the crowding-induced mixing transition of liquid ordered (L o)–liquid disordered (L d) phase separated lipid bilayers when the following particles of increasing size bind to either the L o or L d phase: Ubiquitin, green fluorescent protein (GFP), and nanolipoprotein particles (NLPs) of two diameters. These proteinaceous particles contained histidine-tags, which were phase targeted by binding to iminodiacetic acid (IDA) head groups, via a Cu 2+ chelating mechanism, of lipids that specifically partition into either the Lo phase or Ld phase. The degree of steric pressure was controlled by varying themore » size of the bound particle (10–240 kDa) and the amount of binding sites present (i.e., DPIDA concentrations of 9 and 12 mol%) in the supported lipid multibilayer platform used here. We develop a mass transfer-based diffusional model to analyze the observed L o phase domain dissolution that, along with visual observations and activation energy calculations, provides insight into the sequence of events in crowding-induced mixing. Furthermore, our results suggest that the degree of steric pressure and target phase influence not only the efficacy of steric-pressure induced mixing, but the rate and controlling mechanism for which it occurs.« less

CC2 oscillator strengths within the local framework for calculating excitation energies (LoFEx).

PubMed

Baudin, Pablo; Kjærgaard, Thomas; Kristensen, Kasper

2017-04-14

In a recent work [P. Baudin and K. Kristensen, J. Chem. Phys. 144, 224106 (2016)], we introduced a local framework for calculating excitation energies (LoFEx), based on second-order approximated coupled cluster (CC2) linear-response theory. LoFEx is a black-box method in which a reduced excitation orbital space (XOS) is optimized to provide coupled cluster (CC) excitation energies at a reduced computational cost. In this article, we present an extension of the LoFEx algorithm to the calculation of CC2 oscillator strengths. Two different strategies are suggested, in which the size of the XOS is determined based on the excitation energy or the oscillator strength of the targeted transitions. The two strategies are applied to a set of medium-sized organic molecules in order to assess both the accuracy and the computational cost of the methods. The results show that CC2 excitation energies and oscillator strengths can be calculated at a reduced computational cost, provided that the targeted transitions are local compared to the size of the molecule. To illustrate the potential of LoFEx for large molecules, both strategies have been successfully applied to the lowest transition of the bivalirudin molecule (4255 basis functions) and compared with time-dependent density functional theory.

From Localized Scleroderma to Systemic Sclerosis: Coexistence or Possible Evolution

PubMed Central

Emanuele, Cocchiara; Amelia, Spinella; Clodoveo, Ferri

2018-01-01

Background Systemic sclerosis (SSc) and localized scleroderma (LoS) are two different diseases that may share some features. We evaluated the relationship between SSc and LoS in our case series of SSc patients. Methods We analysed the clinical records of 330 SSc patients, in order to find the eventual occurrence of both the two diseases. Results Eight (2.4%) female patients presented both the two diagnoses in their clinical histories. Six developed LoS prior to SSc; in 4/6 cases, the presence of autoantibodies was observed before SSc diagnosis. Overall, the median time interval between LoS and SSc diagnosis was 18 (range 0–156) months. Conclusions LoS and SSc are two distinct clinical entities that may coexist. Moreover, as anecdotally reported in pediatric populations, we suggested the possible development of SSc in adult patients with LoS, particularly in presence of Raynaud's phenomenon or antinuclear antibodies before the SSc onset. PMID:29666638

Drug-resistant colon cancer cells produce high carcinoembryonic antigen and might not be cancer-initiating cells

PubMed Central

Lee, Hsin-chung; Ling, Qing-Dong; Yu, Wan-Chun; Hung, Chunh-Ming; Kao, Ta-Chun; Huang, Yi-Wei; Higuchi, Akon

2013-01-01

Purpose We evaluated the higher levels of carcinoembryonic antigen (CEA) secreted by the LoVo human colon carcinoma cells in a medium containing anticancer drugs. Drug-resistant LoVo cells were analyzed by subcutaneously xenotransplanting them into mice. The aim of this study was to evaluate whether the drug-resistant cells isolated in this study were cancer-initiating cells, known also as cancer stem cells (CSCs). Methods The production of CEA was investigated in LoVo cells that were cultured with 0–10 mM of anticancer drugs, and we evaluated the increase in CEA production by the LoVo cells that were stimulated by anticancer drug treatment. The expression of several CSC markers in LoVo cells treated with anticancer drugs was also evaluated. Following anticancer drug treatment, LoVo cells were injected subcutaneously into the flanks of severe combined immunodeficiency mice in order to evaluate the CSC fraction. Results Production of CEA by LoVo cells was stimulated by the addition of anticancer drugs. Drug-resistant LoVo cells expressed lower levels of CSC markers, and LoVo cells treated with any of the anticancer drugs tested did not generate tumors within 8 weeks from when the cells were injected subcutaneously into severe combined immunodeficiency mice. These results suggest that the drug-resistant LoVo cells have a smaller population of CSCs than the untreated LoVo cells. Conclusion Production of CEA by LoVo cells can be stimulated by the addition of anticancer drugs. The drug-resistant subpopulation of LoVo colon cancer cells could stimulate the production of CEA, but these cells did not act as CSCs in in vivo tumor generation experiments. PMID:23818760

Cryo Tank Fill at Pad 39B

NASA Image and Video Library

2017-09-26

Several Praxair trucks carrying their loads of liquid oxygen, or LO2, arrive at Launch Pad 39B at NASA's Kennedy Space Center in Florida. The trucks will offload LO2 slowly into a giant storage sphere located at the northwest corner of the pad to gradually chill it down from normal temperature to about negative 298 degrees Fahrenheit, during the first major integrated operation to prepare for the launch of the agency's Orion spacecraft atop the Space Launch System (SLS) rocket. The Ground Systems Development and Operations Program is overseeing upgrades and modifications to pad B to support the launch of the SLS and Orion spacecraft for Exploration Mission-1, deep space missions and NASA’s journey to Mars.

Space Shuttle - Bringing cryohydrogen technology down to earth. [details of LH2 and LO2 technology and External Tank design

NASA Technical Reports Server (NTRS)

Odom, J. B.

1978-01-01

The External Tank must provide a safe storage container for both LH2 and LO2, a means of maintaining propellant quality in order to meet the engine pump net positive suction pressure requirements, and a structural strong-back for the Space Shuttle system, all at the minimum recurring cost and weight, while maintaining quality and reliability. The present paper summarizes External Tank design features and discusses the advantages of using LH2 and LO2 for the Space Shuttle system.

STS-133/ET-137 Tanking Test Photogrammetry Assessment

NASA Technical Reports Server (NTRS)

Oliver, Stanley T.

2012-01-01

Following the launch scrub of Space Shuttle mission STS-133 on November 5, 2010, an anomalous condition of cracked and raised thermal protection system (TPS) foam was observed on the External Tank (ET). Subsequent dissection of the affected TPS region revealed cracks in the feet of two Intertank (IT) metallic stringers. An extensive investigation into the cause(s) and corrective action(s) for the cracked stringers was initiated, involving a wide array of material and structural tests and nondestructive evaluations, with the intent to culminate into the development of flight rational. One such structural test was the instrumented tanking test performed on December 17, 2010. The tanking test incorporated two three-dimensional optical displacement measurement systems to measure full-field outer surface displacements of the TPS surrounding the affected region that contained the stringer cracks. The results showed that the radial displacement and rotation of the liquid oxygen (LO2) tank flange changed significantly as the fluid level of the LO2 approached and passed the LO2 tank flange.

Overview of 10 inch Diameter HTPB Hybrid Motor Testing with Liquid Oxygen at Stennis Space Center

NASA Technical Reports Server (NTRS)

Knowles, Timothy E.; Kearney, Darren; Roberts, Ryan

2005-01-01

To further explore the operation of hybrid rocket motors and to demonstrate the performance characteristics of the motor design Lockheed Martin funded research on a series of 10 inch diameter hybrid motors that produce less than 10 klbf sea level thrust. This test series was given the name "Hybrid Technology Test Program." These motors were fired in the existing test stand at the SSC E-3 complex Cell 1. The fuel and oxidizer for these 10 inch diameter motors are HTPB and LO2, respectively. The original goal of the testing was to verify that the predicted performance matched the actual performance of these 10 inch motors (ref. figure 1) and then confirm that the motors performed acceptably. For this element of testing horizontally fired hybrid motors will be tested using LO2 supplied from the existing facility 100 gallon LO2 tank that is pressurized with facility GN2. The thrust produced by the motor will be measured by a Lockheed Martin supplied load cell.

Olympus receiver evaluation and phase noise measurements

NASA Technical Reports Server (NTRS)

Campbell, Richard L.; Wang, Huailiang; Sweeney, Dennis

1990-01-01

A set of measurements performed by the Michigan Tech Sensing and Signal Processing Group on the analog receiver built by the Virginia Polytechnic Institute (VPI) and the Jet Propulsion Laboratory (JPL) for propagation measurements using the Olympus Satellite is described. Measurements of local oscillator (LO) phase noise were performed for all of the LOs supplied by JPL. In order to obtain the most useful set of measurements, LO phase noise measurements were made using the complete VPI receiver front end. This set of measurements demonstrates the performance of the receiver from the Radio Frequency (RF) input through the high Intermediate Frequency (IF) output. Three different measurements were made: LO phase noise with DC on the voltage controlled crystal oscillator (VCXO) port; LO phase noise with the 11.381 GHz LO locked to the reference signal generator; and a reference measurement with the JPL LOs out of the system.

Chemical Compositions of Ligusticum chuanxiong Oil and Lemongrass Oil and Their Joint Action against Aphis citricola Van Der Goot (Hemiptera: Aphididae).

PubMed

Zhang, Chao; Liu, Runqiang; He, Jun; Ma, Zhiqing; Zhang, Xing

2016-10-12

In order to develop novel botanical insecticides, the joint action of Ligusticum chuanxiong oil (LCO) and lemongrass oil (LO) against Aphis citricola van der Goot was determined systematically indoors and outdoors. The chemical profiles of LCO and LO as determined by gas chromatography-mass spectrometry (GC-MS) analysis revealed that the main compounds from LCO were ( Z )-ligustilide (44.58%) and senkyunolide A (26.92%), and that of LO were geranial (42.16%) and neral (32.58%), respectively. The mixture of LCO and LO showed significant synergy against A. citricola , with a common-toxicity coefficient (CTC) value of 221.46 at the optimal ratio of LCO to LO (4:1, w : w ). Based on the results of solvents and emulsifiers screening, L. chuanxiong oil·Lemongrass oil 20% emulsifiable concentrate (20% LCO·LO EC) was developed, and its stability was confirmed with tests of cold and thermal storage. Field trials indicated that the insecticidal activity of the diluted 20% LCO·LO EC (1000 fold dilution) was comparable to conventional pesticide (20% imidacloprid EC) on A. citricola seven days after application. Thus, the mixture of LCO and LO has the potential to be further developed as a botanical pesticide.

A Digital Backend for the Low Frequency All Sky Monitor

NASA Astrophysics Data System (ADS)

Dartez, L. P.

2014-04-01

The Low Frequency All Sky Monitor (LoFASM) is a distributed array of dipole antennas that are sensitive to radio frequencies from 10 to 88 MHz. The primary science goals of LoFASM are the detection and study of low-frequency radio transients, a high priority science goal as deemed by the National Research Council's decadal survey. LoFASM consists of antennas and front-end electronics that were originally developed for the Long Wavelength Array (LWA) by the U.S. Naval Research Lab, the University of New Mexico, Virginia Tech, and the Jet Propulsion Laboratory. LoFASM, funded by the U.S. Department of Defense, will initially consist of four stations, each consisting of 12 dual-polarization dipole antennas. In a single station, RF signals from each of the individual LoFASM dipoles are combined in phase in order to synthesize LoFASM's beam. The LoFASM RF signals are phased up so that the resulting beam is sensitive to radio emission that originates from the zenith and RF signals approaching from the horizon are attenuated. Digitally, this is achieved using a full Stokes 100MHz correlating spectrometer constructed using field programmable gate array (FPGA) technology. In this thesis I will describe the design and usage of the LoFASM Correlator.

G‐LoSA: An efficient computational tool for local structure‐centric biological studies and drug design

PubMed Central

2016-01-01

Abstract Molecular recognition by protein mostly occurs in a local region on the protein surface. Thus, an efficient computational method for accurate characterization of protein local structural conservation is necessary to better understand biology and drug design. We present a novel local structure alignment tool, G‐LoSA. G‐LoSA aligns protein local structures in a sequence order independent way and provides a GA‐score, a chemical feature‐based and size‐independent structure similarity score. Our benchmark validation shows the robust performance of G‐LoSA to the local structures of diverse sizes and characteristics, demonstrating its universal applicability to local structure‐centric comparative biology studies. In particular, G‐LoSA is highly effective in detecting conserved local regions on the entire surface of a given protein. In addition, the applications of G‐LoSA to identifying template ligands and predicting ligand and protein binding sites illustrate its strong potential for computer‐aided drug design. We hope that G‐LoSA can be a useful computational method for exploring interesting biological problems through large‐scale comparison of protein local structures and facilitating drug discovery research and development. G‐LoSA is freely available to academic users at http://im.compbio.ku.edu/GLoSA/. PMID:26813336

G-LoSA: An efficient computational tool for local structure-centric biological studies and drug design.

PubMed

Lee, Hui Sun; Im, Wonpil

2016-04-01

Molecular recognition by protein mostly occurs in a local region on the protein surface. Thus, an efficient computational method for accurate characterization of protein local structural conservation is necessary to better understand biology and drug design. We present a novel local structure alignment tool, G-LoSA. G-LoSA aligns protein local structures in a sequence order independent way and provides a GA-score, a chemical feature-based and size-independent structure similarity score. Our benchmark validation shows the robust performance of G-LoSA to the local structures of diverse sizes and characteristics, demonstrating its universal applicability to local structure-centric comparative biology studies. In particular, G-LoSA is highly effective in detecting conserved local regions on the entire surface of a given protein. In addition, the applications of G-LoSA to identifying template ligands and predicting ligand and protein binding sites illustrate its strong potential for computer-aided drug design. We hope that G-LoSA can be a useful computational method for exploring interesting biological problems through large-scale comparison of protein local structures and facilitating drug discovery research and development. G-LoSA is freely available to academic users at http://im.compbio.ku.edu/GLoSA/. © 2016 The Protein Society.

LoWMob: Intra-PAN Mobility Support Schemes for 6LoWPAN

PubMed Central

Bag, Gargi; Raza, Muhammad Taqi; Kim, Ki-Hyung; Yoo, Seung-Wha

2009-01-01

Mobility in 6LoWPAN (IPv6 over Low Power Personal Area Networks) is being utilized in realizing many applications where sensor nodes, while moving, sense and transmit the gathered data to a monitoring server. By employing IEEE802.15.4 as a baseline for the link layer technology, 6LoWPAN implies low data rate and low power consumption with periodic sleep and wakeups for sensor nodes, without requiring them to incorporate complex hardware. Also enabling sensor nodes with IPv6 ensures that the sensor data can be accessed anytime and anywhere from the world. Several existing mobility-related schemes like HMIPv6, MIPv6, HAWAII, and Cellular IP require active participation of mobile nodes in the mobility signaling, thus leading to the mobility-related changes in the protocol stack of mobile nodes. In this paper, we present LoWMob, which is a network-based mobility scheme for mobile 6LoWPAN nodes in which the mobility of 6LoWPAN nodes is handled at the network-side. LoWMob ensures multi-hop communication between gateways and mobile nodes with the help of the static nodes within a 6LoWPAN. In order to reduce the signaling overhead of static nodes for supporting mobile nodes, LoWMob proposes a mobility support packet format at the adaptation layer of 6LoWPAN. Also we present a distributed version of LoWMob, named as DLoWMob (or Distributed LoWMob), which employs Mobility Support Points (MSPs) to distribute the traffic concentration at the gateways and to optimize the multi-hop routing path between source and destination nodes in a 6LoWPAN. Moreover, we have also discussed the security considerations for our proposed mobility schemes. The performance of our proposed schemes is evaluated in terms of mobility signaling costs, end-to-end delay, and packet success ratio. PMID:22346730

LoWMob: Intra-PAN Mobility Support Schemes for 6LoWPAN.

PubMed

Bag, Gargi; Raza, Muhammad Taqi; Kim, Ki-Hyung; Yoo, Seung-Wha

2009-01-01

Mobility in 6LoWPAN (IPv6 over Low Power Personal Area Networks) is being utilized in realizing many applications where sensor nodes, while moving, sense and transmit the gathered data to a monitoring server. By employing IEEE802.15.4 as a baseline for the link layer technology, 6LoWPAN implies low data rate and low power consumption with periodic sleep and wakeups for sensor nodes, without requiring them to incorporate complex hardware. Also enabling sensor nodes with IPv6 ensures that the sensor data can be accessed anytime and anywhere from the world. Several existing mobility-related schemes like HMIPv6, MIPv6, HAWAII, and Cellular IP require active participation of mobile nodes in the mobility signaling, thus leading to the mobility-related changes in the protocol stack of mobile nodes. In this paper, we present LoWMob, which is a network-based mobility scheme for mobile 6LoWPAN nodes in which the mobility of 6LoWPAN nodes is handled at the network-side. LoWMob ensures multi-hop communication between gateways and mobile nodes with the help of the static nodes within a 6LoWPAN. In order to reduce the signaling overhead of static nodes for supporting mobile nodes, LoWMob proposes a mobility support packet format at the adaptation layer of 6LoWPAN. Also we present a distributed version of LoWMob, named as DLoWMob (or Distributed LoWMob), which employs Mobility Support Points (MSPs) to distribute the traffic concentration at the gateways and to optimize the multi-hop routing path between source and destination nodes in a 6LoWPAN. Moreover, we have also discussed the security considerations for our proposed mobility schemes. The performance of our proposed schemes is evaluated in terms of mobility signaling costs, end-to-end delay, and packet success ratio.

Performance limitations of label-free sensors in molecular diagnosis using complex samples

NASA Astrophysics Data System (ADS)

Varma, Manoj

2016-03-01

Label-free biosensors promised a paradigm involving direct detection of biomarkers from complex samples such as serum without requiring multistep sample processing typical of labelled methods such as ELISA or immunofluorescence assays. Label-free sensors have witnessed decades of development with a veritable zoo of techniques available today exploiting a multitude of physical effects. It is appropriate now to critically assess whether label-free technologies have succeeded in delivering their promise with respect to diagnostic applications, particularly, ambitious goals such as early cancer detection using serum biomarkers, which require low limits of detection (LoD). Comparison of nearly 120 limits of detection (LoD) values reported by labelled and label-free sensing approaches over a wide range of detection techniques and target molecules in serum revealed that labeled techniques achieve 2-3 orders of magnitude better LoDs. Data from experiments where labelled and label-free assays were performed simultaneously using the same assay parameters also confirm that the LoD achieved by labelled techniques is 2 to 3 orders of magnitude better than that by label-free techniques. Furthermore, label-free techniques required significant signal amplification, for e.g. using nanoparticle conjugated secondary antibodies, to achieve LoDs comparable to labelled methods substantially deviating from the original "direct detection" paradigm. This finding has important implications on the practical limits of applying label-free detection methods for molecular diagnosis.

The Use and Abuse of Limits of Detection in Environmental Analytical Chemistry

PubMed Central

Brown, Richard J. C.

2008-01-01

The limit of detection (LoD) serves as an important method performance measure that is useful for the comparison of measurement techniques and the assessment of likely signal to noise performance, especially in environmental analytical chemistry. However, the LoD is only truly related to the precision characteristics of the analytical instrument employed for the analysis and the content of analyte in the blank sample. This article discusses how other criteria, such as sampling volume, can serve to distort the quoted LoD artificially and make comparison between various analytical methods inequitable. In order to compare LoDs between methods properly, it is necessary to state clearly all of the input parameters relating to the measurements that have been used in the calculation of the LoD. Additionally, the article discusses that the use of LoDs in contexts other than the comparison of the attributes of analytical methods, in particular when reporting analytical results, may be confusing, less informative than quoting the actual result with an accompanying statement of uncertainty, and may act to bias descriptive statistics. PMID:18690384

Integrated Launch Operations Applications Remote Display Developer

NASA Technical Reports Server (NTRS)

Flemming, Cedric M., II

2014-01-01

This internship provides the opportunity to support the creation and use of Firing Room Displays and Firing Room Applications that use an abstraction layer called the Application Control Language (ACL). Required training included video watching, reading assignments, face-to-face instruction and job shadowing other Firing Room software developers as they completed their daily duties. During the training period various computer and access rights needed for creating the applications were obtained. The specific ground subsystems supported are the Cryogenics Subsystems, Liquid Hydrogen (LH2) and Liquid Oxygen (LO2). The cryogenics team is given the task of finding the best way to handle these very volatile liquids that are used to fuel the Space Launch System (SLS) and the Orion flight vehicles safely.

Combustion characteristics of the LO2/GCH4 fuel-rich preburners for staged combustion cycle rocket engines

NASA Astrophysics Data System (ADS)

Ono, Fumiei; Tamura, Hiroshi; Sakamoto, Hiroshi; Sasaki, Masaki

1991-09-01

The combustion characteristics of Liquid Oxygen (LO2)/Gaseous Methane (GCH4) fuel rich preburners were experimentally studied using subscale hardware. Three types of preburners with coaxial type propellant injection elements were designed and fabricated, and were used for hot fire testing. LO2 was used as oxidizer, and GCH4 at room temperature was used as fuel. The tests were conducted at chamber pressures ranging from 6.7 to 11.9 M Pa, and oxidizer to fuel ratios ranged from 0.16 to 0.42. The test results, which include combustion gas temperature T(sub c), characteristic velocity C(sup *) and soot adhesion data, are presented. The T(sub c) efficiency and the C(sup *) efficiency were found to be a function of oxidizer to fuel ratio and chamber pressure. These efficiencies are correlated by an empirical correlation parameter which accounts for the effects of oxidizer to fuel ratio and chamber pressure. The exhaust plumes were colorless and transparent under all tests conditions. There was some soot adhesion to the chamber wall, but no soot adhesion was observed on the main injector simulator orifices. Higher temperature igniter gas was required to ignite the main propellants of the preburner compared with that of the LO2/Gaseous Hydrogen (GH2) propellants combination.

Cryo Tank Fill at Pad 39B

NASA Image and Video Library

2017-09-26

Praxair trucks carrying their loads of liquid oxygen, or LO2, are on their way to Launch Pad 39B at NASA's Kennedy Space Center in Florida. The trucks will offload LO2 slowly into a giant storage sphere located at the northwest corner of the pad to gradually chill it down from normal temperature to about negative 298 degrees Fahrenheit, during the first major integrated operation to prepare for the launch of the agency's Orion spacecraft atop the Space Launch System (SLS) rocket. The Ground Systems Development and Operations Program is overseeing upgrades and modifications to pad B to support the launch of the SLS and Orion spacecraft for Exploration Mission-1, deep space missions and NASA’s journey to Mars.

Cryo Tank Fill at Pad 39B

NASA Image and Video Library

2017-09-26

NASA Launch Director Charlie Blackwell-Thompson, at left, arrives at Launch Pad 39B at NASA's Kennedy Space Center in Florida, to observe the first major tanking operation of liquid oxygen, or LO2, into the giant storage sphere at the northwest corner of the pad to prepare for the launch of the agency's Orion spacecraft atop the Space Launch System (SLS) rocket. During the operation, several Praxair trucks will slowly offload LO2 to gradually chill down the sphere from normal temperature to about negative 298 degrees Fahrenheit. The Ground Systems Development and Operations Program is overseeing upgrades and modifications to pad B to support the launch of the SLS and Orion spacecraft for Exploration Mission-1, deep space missions and NASA’s journey to Mars.

Cryo Tank Fill at Pad 39B

NASA Image and Video Library

2017-09-26

One of several Praxair trucks carrying its load of liquid oxygen, or LO2, is in route to Launch Pad 39B at NASA's Kennedy Space Center in Florida. The truck will offload LO2 slowly into a giant storage sphere located at the northwest corner of the pad to gradually chill it down from normal temperature to about negative 298 degrees Fahrenheit, during the first major integrated operation to prepare for the launch of the agency's Orion spacecraft atop the Space Launch System (SLS) rocket. The Ground Systems Development and Operations Program is overseeing upgrades and modifications to pad B to support the launch of the SLS and Orion spacecraft for Exploration Mission-1, deep space missions and NASA’s journey to Mars.

Cryo Tank Fill at Pad 39B

NASA Image and Video Library

2017-09-26

Several Praxair trucks carrying their loads of liquid oxygen, or LO2, have arrived at Launch Pad 39B at NASA's Kennedy Space Center in Florida. The trucks will offload LO2 slowly into a giant storage sphere located at the northwest corner of the pad to gradually chill it down from normal temperature to about negative 298 degrees Fahrenheit, during the first major integrated operation to prepare for the launch of the agency's Orion spacecraft atop the Space Launch System (SLS) rocket. The Ground Systems Development and Operations Program is overseeing upgrades and modifications to pad B to support the launch of the SLS and Orion spacecraft for Exploration Mission-1, deep space missions and NASA’s journey to Mars.

Higgs boson gluon–fusion production at threshold in N 3LO QCD

DOE PAGES

Anastasiou, Charalampos; Duhr, Claude; Dulat, Falko; ...

2014-09-02

We present the cross-section for the threshold production of the Higgs boson at hadron-colliders at next-to-next-to-next-to-leading order (N 3LO) in perturbative QCD. Furthermore, we present an analytic expression for the partonic cross-section at threshold and the impact of these corrections on the numerical estimates for the hadronic cross-section at the LHC. With this result we achieve a major milestone towards a complete evaluation of the cross-section at N 3LO which will reduce the theoretical uncertainty in the determination of the strengths of the Higgs boson interactions.

ASRDI oxygen technology survey. Volume 4: Low temperature measurement

NASA Technical Reports Server (NTRS)

Sparks, L. L.

1974-01-01

Information is presented on temperature measurement between the triple point and critical point of liquid oxygen. The criterion selected is that all transducers which may reasonably be employed in the liquid oxygen (LO2) temperature range are considered. The temperature range for each transducer is the appropriate full range for the particular thermometer. The discussion of each thermometer or type of thermometer includes the following information: (1) useful temperature range, (2) general and particular methods of construction and the advantages of each type, (3) specifications (accuracy, reproducibility, response time, etc.), (4) associated instrumentation, (5) calibrations and procedures, and (6) analytical representations.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Baroni, A.; Schiavilla, R.

Cross sections for inclusive neutrino scattering off deuteron induced by neutral and charge-changing weak currents are calculated from threshold up to 150 MeV energies in a chiral effective field theory including high orders in the power counting. The contributions beyond leading order (LO) in the weak current are found to be small, and increase the cross sections obtained with the LO transition operators by a couple of percent over the whole energy range (0--150) MeV. Furthermore, the cutoff dependence is negligible, and the predicted cross sections are within ~2% of, albeit consistently larger than, corresponding predictions obtained in conventional meson-exchangemore » frameworks.« less

Higher Order Corrections in the CoLoRFulNNLO Framework

NASA Astrophysics Data System (ADS)

Somogyi, G.; Kardos, A.; Szőr, Z.; Trócsányi, Z.

We discuss the CoLoRFulNNLO method for computing higher order radiative corrections to jet cross sections in perturbative QCD. We apply our method to the calculation of event shapes and jet rates in three-jet production in electron-positron annihilation. We validate our code by comparing our predictions to previous results in the literature and present the jet cone energy fraction distribution at NNLO accuracy. We also present preliminary NNLO results for the three-jet rate using the Durham jet clustering algorithm matched to resummed predictions at NLL accuracy, and a comparison to LEP data.

High-quality two-nucleon potentials up to fifth order of the chiral expansion

NASA Astrophysics Data System (ADS)

Entem, D. R.; Machleidt, R.; Nosyk, Y.

2017-08-01

We present NN potentials through five orders of chiral effective field theory ranging from leading order (LO) to next-to-next-to-next-to-next-to-leading order (N4LO ). The construction may be perceived as consistent in the sense that the same power counting scheme as well as the same cutoff procedures are applied in all orders. Moreover, the long-range parts of these potentials are fixed by the very accurate π N low-energy constants (LECs) as determined in the Roy-Steiner equations analysis by Hoferichter, Ruiz de Elvira, and coworkers. In fact, the uncertainties of these LECs are so small that a variation within the errors leads to effects that are essentially negligible, reducing the error budget of predictions considerably. The NN potentials are fit to the world NN data below the pion-production threshold of the year 2016. The potential of the highest order (N4LO ) reproduces the world NN data with the outstanding χ2/datum of 1.15, which is the highest precision ever accomplished for any chiral NN potential to date. The NN potentials presented may serve as a solid basis for systematic ab initio calculations of nuclear structure and reactions that allow for a comprehensive error analysis. In particular, the consistent order by order development of the potentials will make possible a reliable determination of the truncation error at each order. Our family of potentials is nonlocal and, generally, of soft character. This feature is reflected in the fact that the predictions for the triton binding energy (from two-body forces only) converges to about 8.1 MeV at the highest orders. This leaves room for three-nucleon-force contributions of moderate size.

Consistent, high-quality two-nucleon potentials up to fifth order of the chiral expansion

NASA Astrophysics Data System (ADS)

Machleidt, R.

2018-02-01

We present N N potentials through five orders of chiral effective field theory ranging from leading order (LO) to next-to-next-to-next-to-next-to-leading order (N4LO). The construction may be perceived as consistent in the sense that the same power counting scheme as well as the same cutoff procedures are applied in all orders. Moreover, the long-range parts of these potentials are fixed by the very accurate πN low-energy constants (LECs) as determined in the Roy-Steiner equations analysis by Hoferichter, Ruiz de Elvira and coworkers. In fact, the uncertainties of these LECs are so small that a variation within the errors leads to effects that are essentially negligible, reducing the error budget of predictions considerably. The N N potentials are fit to the world N N data below pion-production threshold of the year of 2016. The potential of the highest order (N4LO) reproduces the world N N data with the outstanding χ 2/datum of 1.15, which is the highest precision ever accomplished for any chiral N N potential to date. The N N potentials presented may serve as a solid basis for systematic ab initio calculations of nuclear structure and reactions that allow for a comprehensive error analysis. In particular, the consistent order by order development of the potentials will make possible a reliable determination of the truncation error at each order. Our family of potentials is non-local and, generally, of soft character. This feature is reflected in the fact that the predictions for the triton binding energy (from two-body forces only) converges to about 8.1 MeV at the highest orders. This leaves room for three-nucleon-force contributions of moderate size.

XYZ-like spectra from Laplace sum rule at N2LO in the chiral limit

NASA Astrophysics Data System (ADS)

Albuquerque, R.; Narison, S.; Fanomezana, F.; Rabemananjara, A.; Rabetiarivony, D.; Randriamanatrika, G.

2016-12-01

We present new compact integrated expressions of QCD spectral functions of heavy-light molecules and four-quark XY Z-like states at lowest order (LO) of perturbative (PT) QCD and up to d = 8 condensates of the Operator Product Expansion (OPE). Then, by including up to next-to-next leading order (N2LO) PT QCD corrections, which we have estimated by assuming the factorization of the four-quark spectral functions, we improve previous LO results from QCD spectral sum rules (QSSR), on the XY Z-like masses and decay constants which suffer from the ill-defined heavy quark mass. PT N3LO corrections are estimated using a geometric growth of the PT series and are included in the systematic errors. Our optimal results based on stability criteria are summarized in Tables 11-14 and compared, in Sec. 10, with experimental candidates and some LO QSSR results. We conclude that the masses of the XZ observed states are compatible with (almost) pure JPC = 1+±, 0++ molecule or/and four-quark states. The ones of the 1-±, 0-± molecule/four-quark states are about 1.5 GeV above the Yc,b mesons experimental candidates and hadronic thresholds. We also find that the couplings of these exotics to the associated interpolating currents are weaker than that of ordinary D,B mesons (fDD ≈ 10-3f D) and may behave numerically as 1/m¯b3/2 (respectively 1/m¯b) for the 1+, 0+ (respectively 1-, 0-) states which can stimulate further theoretical studies of these decay constants.

An evaluation of two hands-on lab styles for plant biodiversity in undergraduate biology.

PubMed

Basey, John M; Maines, Anastasia P; Francis, Clinton D; Melbourne, Brett

2014-01-01

We compared learning cycle and expository formats for teaching about plant biodiversity in an inquiry-oriented university biology lab class (n = 465). Both formats had preparatory lab activities, a hands-on lab, and a postlab with reflection and argumentation. Learning was assessed with a lab report, a practical quiz in lab, and a multiple-choice exam in the concurrent lecture. Attitudes toward biology and treatments were also assessed. We used linear mixed-effect models to determine impacts of lab style on lower-order cognition (LO) and higher-order cognition (HO) based on Bloom's taxonomy. Relative to the expository treatment, the learning cycle treatment had a positive effect on HO and a negative effect on LO included in lab reports; a positive effect on transfer of LO from the lab report to the quiz; negative impacts on LO quiz performance and on attitudes toward the lab; and a higher degree of perceived difficulty. The learning cycle treatment had no influence on transfer of HO from lab report to quiz or exam; quiz performance on HO questions; exam performance on LO and HO questions; and attitudes toward biology as a science. The importance of LO as a foundation for HO relative to these lab styles is addressed. © 2014 J. M. Basey et al. CBE—Life Sciences Education © 2014 The American Society for Cell Biology. This article is distributed by The American Society for Cell Biology under license from the author(s). It is available to the public under an Attribution–Noncommercial–Share Alike 3.0 Unported Creative Commons License (http://creativecommons.org/licenses/by-nc-sa/3.0).

Cyanobacteria for Human Habitation beyond Earth

NASA Technical Reports Server (NTRS)

Brown, Igor; Jones, Jeff; Bayless, David; Sarkisova, Svetlana; Garrison, Dan; McKay, David S.

2007-01-01

In light of the President s Moon/Mars initiative, lunar exploration has once again become a priority for NASA. In order to establish permanent bases on the Moon and proceed with human exploration of Mars, two key problems will be addressed: first, the production of O2 and second, the production of methane (CH4). While O2 is required for life support systems (LSS), both liquid O2 and CH4 are needed as an oxidizer and a propellant, respectively for the Lunar Surface Access Module (LSAM) and the Crew Exploration Vehicle (CEV). Unlike previous propulsion systems, the new CEV will use liquid oxygen (LO2) as an oxidizer and liquid methane (LCH4) as a propellant. Existing technology (e.g. hydrogen reduction) for the production of liquid oxygen from lunar regolith is very energy intensive and requires high temperature reactors. We propose an alternative approach using iron-tolerant cyanobacteria. We have found that iron-tolerant cyanobacteria (IT CB) are capable of etching iron-bearing minerals, which may lead to bonds breaking between Fe and O of common lunar mare basalt Fe-oxides including ilmenite, pseudobrookite, ferropseudobrookite, and armalcolite with the subsequent release of both Fe, Ti and oxygen as byproducts. We also propose to use CB biomass for CH4 production as carbon stock and a propellant. Both processes can be accomplished in an energy and cost effective manner because sunlight will be used as an energy source and allows the reactions at ambient temperatures between 10-60 C. Current evaluations include assessing the thermodynamics of such biogenic reactions using a variety of nutrients and atmospheric parameters, as well as assessing the rates and species variation effects of the driving reactions.

Iron-Tolerant Cyanobacteria for Human Habitation beyond Earth

NASA Technical Reports Server (NTRS)

Brown, Igor; Sarkisova, Svetlana; Jones, Jeff; Sternberg, Paul; Bayless, David; Mckay, David S.

2006-01-01

In light of the President's Moon/Mars initiative, lunar exploration has once again become a priority for NASA. In order to establish permanent bases on the Moon and proceed with human exploration of Mars, two key problems will be addressed: first, the production of O2 and second, the production of methane (CH4). While O2 is required for life support systems (LSS), both liquid O2 and CH4 are needed as an oxidizer and a propellant, respectively for the Lunar Surface Access Module (LSAM) and the Crew Exploration Vehicle (CEV). Unlike previous propulsion systems, the new CEV will use liquid oxygen (LO2) as an oxidizer and liquid methane (LCH4) as a propellant. Existing technology (e.g. hydrogen reduction) for the production of liquid oxygen from lunar regolith is very energy intensive and requires high temperature reactors. We propose an alternative approach using iron-tolerant cyanobacteria. We have found that iron-tolerant cyanobacteria (IT CB) are capable of etching iron-bearing minerals, which may lead to bonds breaking between Fe and O of common lunar mare basalt Feoxides including ilmenite, pseudobrookite, ferropseudobrookite, and armalcolite with the subsequent release of both Fe, Ti and oxygen as by-products. We also propose to use CB biomass for CH4 production as carbon stock and a propellant. Both processes can be accomplished in an energy and cost effective manner because sunlight will be used as an energy source and allows the reactions at ambient temperatures between 10-60 C. Current evaluations include assessing the thermodynamics of such biogenic reactions using a variety of nutrients and atmospheric parameters, as well as assessing the rates and species variation effects of the driving reactions.

Liquid Nitrogen (Oxygen Simulant) Thermodynamic Vent System Test Data Analysis

NASA Technical Reports Server (NTRS)

Hedayat, A.; Nelson, S. L.; Hastings, L. J.; Flachbart, R. H.; Tucker, S. P.

2005-01-01

In designing systems for the long-term storage of cryogens in low-gravity (space) environments, one must consider the effects of thermal stratification on tank pressure that will occur due to environmental heat leaks. During low-gravity operations, a Thermodynamic Vent System (TVS) concept is expected to maintain tank pressure without propellant resettling. A series of TVS tests was conducted at NASA Marshall Space Flight Center (MSFC) using liquid nitrogen (LN2) as a liquid oxygen (LO2) simulant. The tests were performed at tank til1 levels of 90%, 50%, and 25%, and with a specified tank pressure control band. A transient one-dimensional TVS performance program is used to analyze and correlate the test data for all three fill levels. Predictions and comparisons of ullage pressure and temperature and bulk liquid saturation pressure and temperature with test data are presented.

Cryogenic Propellant Management Device: Conceptual Design Study

NASA Technical Reports Server (NTRS)

Wollen, Mark; Merino, Fred; Schuster, John; Newton, Christopher

2010-01-01

Concepts of Propellant Management Devices (PMDs) were designed for lunar descent stage reaction control system (RCS) and lunar ascent stage (main and RCS propulsion) missions using liquid oxygen (LO2) and liquid methane (LCH4). Study ground rules set a maximum of 19 days from launch to lunar touchdown, and an additional 210 days on the lunar surface before liftoff. Two PMDs were conceptually designed for each of the descent stage RCS propellant tanks, and two designs for each of the ascent stage main propellant tanks. One of the two PMD types is a traditional partial four-screen channel device. The other type is a novel, expanding volume device which uses a stretched, flexing screen. It was found that several unique design features simplified the PMD designs. These features are (1) high propellant tank operating pressures, (2) aluminum tanks for propellant storage, and (3) stringent insulation requirements. Consequently, it was possible to treat LO2 and LCH4 as if they were equivalent to Earth-storable propellants because they would remain substantially subcooled during the lunar mission. In fact, prelaunch procedures are simplified with cryogens, because any trapped vapor will condense once the propellant tanks are pressurized in space.

Dynamics of crowding-induced mixing in phase separated lipid bilayers

DOE PAGES

Zeno, Wade F.; Johnson, Kaitlin E.; Sasaki, Darryl Y.; ...

2016-10-10

We use fluorescence microscopy to examine the dynamics of the crowding-induced mixing transition of liquid ordered (L o)–liquid disordered (L d) phase separated lipid bilayers when the following particles of increasing size bind to either the L o or L d phase: Ubiquitin, green fluorescent protein (GFP), and nanolipoprotein particles (NLPs) of two diameters. These proteinaceous particles contained histidine-tags, which were phase targeted by binding to iminodiacetic acid (IDA) head groups, via a Cu 2+ chelating mechanism, of lipids that specifically partition into either the Lo phase or Ld phase. The degree of steric pressure was controlled by varying themore » size of the bound particle (10–240 kDa) and the amount of binding sites present (i.e., DPIDA concentrations of 9 and 12 mol%) in the supported lipid multibilayer platform used here. We develop a mass transfer-based diffusional model to analyze the observed L o phase domain dissolution that, along with visual observations and activation energy calculations, provides insight into the sequence of events in crowding-induced mixing. Furthermore, our results suggest that the degree of steric pressure and target phase influence not only the efficacy of steric-pressure induced mixing, but the rate and controlling mechanism for which it occurs.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Boroun, G. R., E-mail: grboroun@gmail.com, E-mail: boroun@razi.ac.ir; Zarrin, S.

We derive a general scheme for the evolution of the nonsinglet structure function at the leadingorder (LO) and next-to-leading-order (NLO) by using the Laplace-transform technique. Results for the nonsinglet structure function are compared with MSTW2008, GRV, and CKMT parameterizations and also EMC experimental data in the LO and NLO analysis. The results are in good agreement with the experimental data and other parameterizations in the low- and large-x regions.

Four-Wave-Mixing Oscillations in a simplified Boltzmannian semiconductor model with LO-phonons

NASA Astrophysics Data System (ADS)

Tamborenea, P. I.; Bányai, L.; Haug, H.

1996-03-01

The recently discovered(L. Bányai, D. B. Tran Thoai, E. Reitsamer, H. Haug, D. Steinbach, M. U. Wehner, M. Wegener, T. Marschner and W. Stolz, Phys. Rev. Lett. 75), 2188 (1995). oscillations of the integrated four-wave-mixing signal in semiconductors due to electron-LO-phonon scattering are studied within a simplified Boltzmann-type model. Although several aspects of the experimental results require a description within the framework of non-Markovian quantum-kinetic theory, our simplified Boltzmannian model is well suited to analyze the origin of the observed novel oscillations of frequency (1+m_e/m_h) hbarω_LO. To this end, we developed a third-order, analytic solution of the semiconductor Bloch equations (SBE) with Boltzmann-type, LO-phonon collision terms. Results of this theory along with numerical solutions of the SBE will be presented.

Liquid Nitrogen Zero Boiloff Testing

NASA Technical Reports Server (NTRS)

Plachta, David; Feller, Jeffrey; Johnson, Wesley; Robinson, Craig

2017-01-01

Cryogenic propellants such as liquid hydrogen (LH2) and liquid oxygen (LO2) are a part of NASAs future space exploration due to their high specific impulse for rocket motors of upper stages suitable for transporting 10s to 100s of metric tons of payload mass to destinations outside of low earth orbit and for their return. However, the low storage temperatures of LH2 and LO2 cause substantial boil-off losses for missions with durations greater than several months. These losses can be eliminated by incorporating high performance cryocooler technology to intercept heat load to the propellant tanks and modulating the cryocooler to control tank pressure. The active thermal control technology being developed by NASA is the reverse turbo-Brayton cycle cryocooler and its integration to the propellant tank through a distributed cooling tubing network coupled to the tank wall. This configuration was recently tested at NASA Glenn Research Center, in a vacuum chamber and cryo-shroud that simulated the essential thermal aspects of low Earth orbit, its vacuum and temperature. Testing consisted of three passive tests with the active cryo-cooler system off, and 7 active tests, with the cryocooler powered up. The test matrix included zero boil-off tests performed at 90 full and 25 full, and several demonstrations at excess cooling capacity and reduced cooling capacity. From this, the tank pressure response with varied cryocooler power inputs was determined. This test series established that the active cooling system integrated with the propellant tank eliminated boil-off and robustly controlled tank pressure.

Cryo Tank Fill at Pad 39B

NASA Image and Video Library

2017-09-26

NASA Launch Director Charlie Blackwell-Thompson, center, talks to engineers at Launch Pad 39B at the agency's Kennedy Space Center in Florida. Blackwell-Thompson will observe the first major tanking operation of liquid oxygen, or LO2, into the giant storage sphere at the northwest corner of the pad to prepare for the launch of the agency's Orion spacecraft atop the Space Launch System (SLS) rocket. During the operation, several Praxair trucks will slowly offload LO2 to gradually chill down the sphere from normal temperature to about negative 298 degrees Fahrenheit. The Ground Systems Development and Operations Program is overseeing upgrades and modifications to pad B to support the launch of the SLS and Orion spacecraft for Exploration Mission-1, deep space missions and NASA’s journey to Mars.

Cryo Tank Fill at Pad 39B

NASA Image and Video Library

2017-09-26

NASA Launch Director Charlie Blackwell-Thompson, at right, greets engineers and technicians at Launch Pad 39B at the agency's Kennedy Space Center in Florida. Blackwell-Thompson will observe the first major tanking operation of liquid oxygen, or LO2, into the giant storage sphere at the northwest corner of the pad to prepare for the launch of the agency's Orion spacecraft atop the Space Launch System (SLS) rocket. During the operation, several Praxair trucks will slowly offload LO2 to gradually chill down the sphere from normal temperature to about negative 298 degrees Fahrenheit. The Ground Systems Development and Operations Program is overseeing upgrades and modifications to pad B to support the launch of the SLS and Orion spacecraft for Exploration Mission-1, deep space missions and NASA’s journey to Mars.

Cryo Tank Fill at Pad 39B

NASA Image and Video Library

2017-09-26

Several Praxair trucks carrying their loads of liquid oxygen, or LO2, have arrived at Launch Pad 39B at NASA's Kennedy Space Center in Florida. A mist is visible as LO2 is offloaded from one of the trucks into the giant storage sphere located at the northwest corner of the pad has begun. The sphere will gradually be chilled down from normal temperature to about negative 298 degrees Fahrenheit, during the first major integrated operation to prepare for the launch of the agency's Orion spacecraft atop the Space Launch System (SLS) rocket. The Ground Systems Development and Operations Program is overseeing upgrades and modifications to pad B to support the launch of the SLS and Orion spacecraft for Exploration Mission-1, deep space missions and NASA’s journey to Mars.

Cryo Tank Fill at Pad 39B

NASA Image and Video Library

2017-09-26

Several Praxair trucks carrying their loads of liquid oxygen, or LO2, have arrived at Launch Pad 39B at NASA's Kennedy Space Center in Florida. The trucks will begin to offload the LO2 one at a time into the giant storage sphere located at the northwest corner of the pad. The sphere will gradually be chilled down from normal temperature to about negative 298 degrees Fahrenheit, during the first major integrated operation to prepare for the launch of the agency's Orion spacecraft atop the Space Launch System (SLS) rocket. The Ground Systems Development and Operations Program is overseeing upgrades and modifications to pad B to support the launch of the SLS and Orion spacecraft for Exploration Mission-1, deep space missions and NASA’s journey to Mars.

Cryo Tank Fill at Pad 39B

NASA Image and Video Library

2017-09-26

Engineers watch as several Praxair trucks carrying their loads of liquid oxygen, or LO2, arrive at Launch Pad 39B at NASA's Kennedy Space Center in Florida. The trucks will offload the LO2 one at a time into the giant storage sphere located at the northwest corner of the pad. The sphere will gradually be chilled down from normal temperature to about negative 298 degrees Fahrenheit, during the first major integrated operation to prepare for the launch of the agency's Orion spacecraft atop the Space Launch System (SLS) rocket. The Ground Systems Development and Operations Program is overseeing upgrades and modifications to pad B to support the launch of the SLS and Orion spacecraft for Exploration Mission-1, deep space missions and NASA’s journey to Mars.

Agreement Between Autorefraction and Subjective Refraction in Keraring-Implanted Keratoconic Eyes.

PubMed

Al-Tuwairqi, Waleed S; Ogbuehi, Kelechi C; Razzouk, Haya; Alanazi, Mana A; Osuagwu, Uchechukwu L

2017-03-01

To assess the agreement between subjective refraction and autorefraction and to explore the relationship between the magnitude of higher order aberration, and visual acuity and refraction, before and after keraring implantation. This prospective, randomized, interventional study enrolled 27 subjects (mean age 28.1±6.5 years) with keratoconus. Noncycloplegic refraction was performed subjectively by one clinician and with an autorefractor by another clinician, before and 6 months after surgery. The limit of agreement (LoA) between methods was assessed, and the relationships between the corrected distance visual acuity, logMAR on the one hand and refraction measurements and higher-order aberrations on the other, were examined. The agreement in mean spherical equivalent refraction (MSER) between methods was good postoperatively but poor preoperatively. The autorefractor gave a more myopic refraction than subjective refraction preoperatively (-3.28±3.06 D; LoA -9.27 to +2.71 D, P<0.0001) and postoperatively (-0.63±1.64 D; LoA -3.85 to +2.58 D, P=0.055), and returned higher negative cylinders preoperatively (-1.10±1.17 D; LoA -3.40 to +1.19 D, P<0.0001) and postoperatively (-1.08±1.27 D; LoA -3.60 to +1.41 D, P<0.0001) in keratoconic eyes. The difference in MSER between methods was significantly related to the refractive error at both visits (P<0.05) and to the magnitude of higher-order aberrations in keratoconic eyes preoperatively (P<0.05). The logMAR visual acuity achieved subjectively worsened as the magnitude of higher-order aberrations increased preoperatively (P<0.001). The autorefractor returns values that are significantly more myopic in MSER and higher negative cylinders than subjective refraction, preoperatively, but the MSER was similar between devices postoperatively. The autorefactor seems a valid starting point for subjective refraction in keratoconic eyes treated with keraring, but the cylinder should be corrected by about +1 D. The instruments agree more in less myopic than high myopic eyes.

Detection of submicron-sized raft-like domains in membranes by small-angle neutron scattering

NASA Astrophysics Data System (ADS)

Pencer, J.; Mills, T.; Anghel, V.; Krueger, S.; Epand, R. M.; Katsaras, J.

2005-12-01

Using coarse grained models of heterogeneous vesicles we demonstrate the potential for small-angle neutron scattering (SANS) to detect and distinguish between two different categories of lateral segregation: 1) unilamellar vesicles (ULV) containing a single domain and 2) the formation of several small domains or “clusters” (~10 nm in radius) on a ULV. Exploiting the unique sensitivity of neutron scattering to differences between hydrogen and deuterium, we show that the liquid ordered (lo) DPPC-rich phase can be selectively labeled using chain deuterated dipalymitoyl phosphatidylcholine (dDPPC), which greatly facilitates the use of SANS to detect membrane domains. SANS experiments are then performed in order to detect and characterize, on nanometer length scales, lateral heterogeneities, or so-called “rafts”, in ~30 nm radius low polydispersity ULV made up of ternary mixtures of phospholipids and cholesterol. For 1:1:1 DOPC:DPPC:cholesterol (DDC) ULV we find evidence for the formation of lateral heterogeneities on cooling below 30 °C. These heterogeneities do not appear when DOPC is replaced by SOPC. Fits to the experimental data using coarse grained models show that, at room temperature, DDC ULV each exhibit approximately 30 domains with average radii of ~10 nm.

Soft Expansion of Double-Real-Virtual Corrections to Higgs Production at N$^3$LO

DOE PAGES

Anastasiou, Charalampos; Duhr, Claude; Dulat, Falko; ...

2015-05-15

We present methods to compute higher orders in the threshold expansion for the one-loop production of a Higgs boson in association with two partons at hadron colliders. This process contributes to the N 3LO Higgs production cross section beyond the soft-virtual approximation. We use reverse unitarity to expand the phase-space integrals in the small kinematic parameters and to reduce the coefficients of the expansion to a small set of master integrals. We describe two methods for the calculation of the master integrals. The first was introduced for the calculation of the soft triple-real radiation relevant to N 3LO Higgs production.more » The second uses a particular factorization of the three body phase-space measure and the knowledge of the scaling properties of the integral itself. Our result is presented as a Laurent expansion in the dimensional regulator, although some of the master integrals are computed to all orders in this parameter.« less

Loss-of-function variants influence the human serum metabolome

PubMed Central

Yu, Bing; Li, Alexander H.; Metcalf, Ginger A.; Muzny, Donna M.; Morrison, Alanna C.; White, Simon; Mosley, Thomas H.; Gibbs, Richard A.; Boerwinkle, Eric

2016-01-01

The metabolome is a collection of small molecules resulting from multiple cellular and biological processes that can act as biomarkers of disease, and African-Americans exhibit high levels of genetic diversity. Exome sequencing of a sample of deeply phenotyped African-Americans allowed us to analyze the effects of annotated loss-of-function (LoF) mutations on 308 serum metabolites measured by untargeted liquid and gas chromatography coupled with mass spectrometry. In an independent sample, we identified and replicated four genes harboring six LoF mutations that significantly affected five metabolites. These sites were related to a 19 to 45% difference in geometric mean metabolite levels, with an average effect size of 25%. We show that some of the affected metabolites are risk predictors or diagnostic biomarkers of disease and, using the principle of Mendelian randomization, are in the causal pathway of disease. For example, LoF mutations in SLCO1B1 elevate the levels of hexadecanedioate, a fatty acid significantly associated with increased blood pressure levels and risk of incident heart failure in both African-Americans and an independent sample of European-Americans. We show that SLCO1B1 LoF mutations significantly increase the risk of incident heart failure, thus implicating the metabolite in the causal pathway of disease. These results reveal new avenues into gene function and the understanding of disease etiology by integrating -omic technologies into a deeply phenotyped population study. PMID:27602404

Technical note: Simultaneous carotenoid and vitamin analysis of milk from total mixed ration-fed cows optimized for xanthophyll detection.

PubMed

Stout, M A; Benoist, D M; Drake, M A

2018-06-01

Concentrations of retinol, α-tocopherol, and major carotenoids in dairy products are often determined simultaneously by liquid chromatography. These compounds have different polarity and solubility; thus, extracting them simultaneously can be difficult and inefficient. In milks with low carotenoid concentrations, the xanthophylls lutein and zeaxanthin may not be completely resolved using common extraction techniques. A simplified method was developed to optimize extraction efficiency and the limit of detection and limit of quantification (LoQ) of lutein and zeaxanthin in bovine milk without decreasing sensitivity to other vitamins or carotenoids. The developed method evaluates lutein, zeaxanthin, β-carotene, retinol, and α-tocopherol simultaneously by ultra-high performance liquid chromatography-photodiode array detection. Common saponification temperatures (40-60°C) and concentrations of KOH in water (10-50% KOH wt/vol) were evaluated. Multiple solvents were evaluated for optimal xanthophyll extraction (diethyl ether, dichloromethane, hexane, and tetrahydrofuran) following saponification. The limit of detection and LoQ were defined as 3:1 and 10:1 signal-to-noise ratio, respectively. All experiments were performed in triplicate. The optimal saponification procedure was a concentration of 25% KOH at either 40 or 50°C. Saponified extracts solubilized in solutions containing diethyl ether had greater concentrations of lutein- than hexane- or tetrahydrofuran-based solutions, with peak areas above LoQ values. The solution containing diethyl ether solubilized similar concentrations of retinol, α-tocopherol, and β-carotene when compared with other solutions. The proposed optimized method allows for the simultaneous determination of carotenoids from milk with increased lutein and zeaxanthin sensitivity without sacrificing recovery of retinol, α-tocopherol, and β-carotene. Copyright © 2018 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Aeroelastic Response and Protection of Space Shuttle External Tank Cable Trays

NASA Technical Reports Server (NTRS)

Edwards, John W.; Keller, Donald F.; Schuster, David M.; Piatak, David J.; Rausch, Russ D.; Bartels, Robert E.; Ivanco, Thomas G.; Cole, Stanley R.; Spain, Charles V.

2005-01-01

Sections of the Space Shuttle External Tank Liquid Oxygen (LO2) and Liquid Hydrogen (LH2) cable trays are shielded from potentially damaging airloads with foam Protuberance Aerodynamic Load (PAL) Ramps. Flight standard design LO2 and LH2 cable tray sections were tested with and without PAL Ramp models in the United States Air Force Arnold Engineering Development Center s (AEDC) 16T transonic wind tunnel to obtain experimental data on the aeroelastic stability and response characteristics of the trays and as part of the larger effort to determine whether the PAL ramps can be safely modified or removed. Computational Fluid Dynamic simulations of the full-stack shuttle launch configuration were used to investigate the flow characeristics around and under the cable trays without the protective PAL ramps and to define maximum crossflow Mach numbers and dynamic pressures experienced during launch. These crossflow conditions were used to establish wind tunnel test conditions which also included conservative margins. For all of the conditions and configurations tested, no aeroelastic instabilities or unacceptable dynamic response levels were encountered and no visible structural damage was experienced by any of the tested cable tray sections. Based upon this aeroelastic characterization test, three potentially acceptable alternatives are available for the LO2 cable tray PAL Ramps: Mini-Ramps, Tray Fences, or No Ramps. All configurations were tested to maximum conditions, except the LH2 trays at -15 deg. crossflow angle. This exception is the only caveat preventing the proposal of acceptable alternative configurations for the LH2 trays as well. Structural assessment of all tray loads and tray response measurements from launches following the Shuttle Return To Flight with the existing PAL Ramps will determine the acceptability of these PAL Ramp alternatives.

Experimental Investigation of Augmented Spark Ignition of a LO2/LCH4 Reaction Control Engine at Altitude Conditions

NASA Technical Reports Server (NTRS)

Kleinhenz, Julie; Sarmiento, Charles; Marshall, William

2012-01-01

The use of nontoxic propellants in future exploration vehicles would enable safer, more cost-effective mission scenarios. One promising green alternative to existing hypergols is liquid methane (LCH4) with liquid oxygen (LO2). A 100 lbf LO2/LCH4 engine was developed under the NASA Propulsion and Cryogenic Advanced Development project and tested at the NASA Glenn Research Center Altitude Combustion Stand in a low pressure environment. High ignition energy is a perceived drawback of this propellant combination; so this ignition margin test program examined ignition performance versus delivered spark energy. Sensitivity of ignition to spark timing and repetition rate was also explored. Three different exciter units were used with the engine s augmented (torch) igniter. Captured waveforms indicated spark behavior in hot fire conditions was inconsistent compared to the well-behaved dry sparks. This suggests that rising pressure and flow rate increase spark impedance and may at some point compromise an exciter s ability to complete each spark. The reduced spark energies of such quenched deliveries resulted in more erratic ignitions, decreasing ignition probability. The timing of the sparks relative to the pressure/flow conditions also impacted the probability of ignition. Sparks occurring early in the flow could trigger ignition with energies as low as 1 to 6 mJ, though multiple, similarly timed sparks of 55 to 75 mJ were required for reliable ignition. Delayed spark application and reduced spark repetition rate both correlated with late and occasional failed ignitions. An optimum time interval for spark application and ignition therefore coincides with propellant introduction to the igniter.

Computational fluid dynamics analysis of space shuttle main propulsion feed line 17-inch disconnect valves

NASA Technical Reports Server (NTRS)

Kandula, Max; Pearce, Daniel

1989-01-01

A steady incompressible three-dimensional (3-D) viscous flow analysis was conducted for the Space Shuttle Main Propulsion External Tank (ET)/Orbiter (ORB) propellant feed line quick separable 17-inch disconnect flapper valves for liquid oxygen (LO2) and liquid hydrogen (LH2). The main objectives of the analysis were to predict and correlate the hydrodynamic stability of the flappers and pressure drop with available water test data. Computational Fluid Dynamics (CFD) computer codes were procured at no cost from the public domain, and were modified and extended to carry out the disconnect flow analysis. The grid generator codes SVTGD3D and INGRID were obtained. NASA Ames Research Center supplied the flow solution code INS3D, and the color graphics code PLOT3D. A driver routine was developed to automate the grid generation process. Components such as pipes, elbows, and flappers can be generated with simple commands, and flapper angles can be varied easily. The flow solver INS3D code was modified to treat interior flappers, and other interfacing routines were developed, which include a turbulence model, a force/moment routine, a time-step routine, and initial and boundary conditions. In particular, an under-relaxation scheme was implemented to enhance the solution stability. Major physical assumptions and simplifications made in the analysis include the neglect of linkages, slightly reduced flapper diameter, and smooth solid surfaces. A grid size of 54 x 21 x 25 was employed for both the LO2 and LH2 units. Mixing length theory applied to turbulent shear flow in pipes formed the basis for the simple turbulence model. Results of the analysis are presented for LO2 and LH2 disconnects.

Vector-Boson Fusion Higgs Production at Three Loops in QCD.

PubMed

Dreyer, Frédéric A; Karlberg, Alexander

2016-08-12

We calculate the next-to-next-to-next-to-leading-order (N^{3}LO) QCD corrections to inclusive vector-boson fusion Higgs production at proton colliders, in the limit in which there is no color exchange between the hadronic systems associated with the two colliding protons. We also provide differential cross sections for the Higgs transverse momentum and rapidity distributions. We find that the corrections are at the 1‰-2‰ level, well within the scale uncertainty of the next-to-next-to-leading-order calculation. The associated scale uncertainty of the N^{3}LO calculation is typically found to be below the 2‰ level. We also consider theoretical uncertainties due to missing higher order parton distribution functions, and provide an estimate of their importance.

Enhancing LoRaWAN Security through a Lightweight and Authenticated Key Management Approach.

PubMed

Sanchez-Iborra, Ramon; Sánchez-Gómez, Jesús; Pérez, Salvador; Fernández, Pedro J; Santa, José; Hernández-Ramos, José L; Skarmeta, Antonio F

2018-06-05

Luckily, new communication technologies and protocols are nowadays designed considering security issues. A clear example of this can be found in the Internet of Things (IoT) field, a quite recent area where communication technologies such as ZigBee or IPv6 over Low power Wireless Personal Area Networks (6LoWPAN) already include security features to guarantee authentication, confidentiality and integrity. More recent technologies are Low-Power Wide-Area Networks (LP-WAN), which also consider security, but present initial approaches that can be further improved. An example of this can be found in Long Range (LoRa) and its layer-two supporter LoRa Wide Area Network (LoRaWAN), which include a security scheme based on pre-shared cryptographic material lacking flexibility when a key update is necessary. Because of this, in this work, we evaluate the security vulnerabilities of LoRaWAN in the area of key management and propose different alternative schemes. Concretely, the application of an approach based on the recently specified Ephemeral Diffie⁻Hellman Over COSE (EDHOC) is found as a convenient solution, given its flexibility in the update of session keys, its low computational cost and the limited message exchanges needed. A comparative conceptual analysis considering the overhead of different security schemes for LoRaWAN is carried out in order to evaluate their benefits in the challenging area of LP-WAN.

Neutron-proton scattering at next-to-next-to-leading order in Nuclear Lattice Effective Field Theory

DOE PAGES

Alarcón, Jose Manuel; Du, Dechuan; Klein, Nico; ...

2017-05-08

Here, we present a systematic study of neutron-proton scattering in Nuclear Lattice Effective Field Theory (NLEFT), in terms of the computationally efficient radial Hamiltonian method. Our leading-order (LO) interaction consists of smeared, local contact terms and static one-pion exchange. We show results for a fully non-perturbative analysis up to next-to-next-to-leading order (NNLO), followed by a perturbative treatment of contributions beyond LO. The latter analysis anticipates practical Monte Carlo simulations of heavier nuclei. We explore how our results depend on the lattice spacing a, and estimate sources of uncertainty in the determination of the low-energy constants of the next-to-leading-order (NLO) two-nucleonmore » force. We give results for lattice spacings ranging from a = 1.97 fm down to a = 0.98 fm, and discuss the effects of lattice artifacts on the scattering observables. At a = 0.98 fm, lattice artifacts appear small, and our NNLO results agree well with the Nijmegen partial-wave analysis for S-wave and P-wave channels. We expect the peripheral partial waves to be equally well described once the lattice momenta in the pion-nucleon coupling are taken to coincide with the continuum dispersion relation, and higher-order (N 3LO) contributions are included. Finally, we stress that for center-of-mass momenta below 100 MeV, the physics of the two-nucleon system is independent of the lattice spacing.« less

First-order kinetic gas generation model parameters for wet landfills.

PubMed

Faour, Ayman A; Reinhart, Debra R; You, Huaxin

2007-01-01

Landfill gas collection data from wet landfill cells were analyzed and first-order gas generation model parameters were estimated for the US EPA landfill gas emissions model (LandGEM). Parameters were determined through statistical comparison of predicted and actual gas collection. The US EPA LandGEM model appeared to fit the data well, provided it is preceded by a lag phase, which on average was 1.5 years. The first-order reaction rate constant, k, and the methane generation potential, L(o), were estimated for a set of landfills with short-term waste placement and long-term gas collection data. Mean and 95% confidence parameter estimates for these data sets were found using mixed-effects model regression followed by bootstrap analysis. The mean values for the specific methane volume produced during the lag phase (V(sto)), L(o), and k were 33 m(3)/Megagrams (Mg), 76 m(3)/Mg, and 0.28 year(-1), respectively. Parameters were also estimated for three full scale wet landfills where waste was placed over many years. The k and L(o) estimated for these landfills were 0.21 year(-1), 115 m(3)/Mg, 0.11 year(-1), 95 m(3)/Mg, and 0.12 year(-1) and 87 m(3)/Mg, respectively. A group of data points from wet landfills cells with short-term data were also analyzed. A conservative set of parameter estimates was suggested based on the upper 95% confidence interval parameters as a k of 0.3 year(-1) and a L(o) of 100 m(3)/Mg if design is optimized and the lag is minimized.

Heavy quark diffusion in strong magnetic fields at weak coupling and implications for elliptic flow

DOE PAGES

Fukushima, Kenji; Hattori, Koichi; Yee, Ho -Ung; ...

2016-04-20

In this paper, we compute the momentum diffusion coefficients of heavy quarks, κ ∥ and κ ⊥, in a strong magnetic field B along the directions parallel and perpendicular to B, respectively, at the leading order in QCD coupling constant α s. We consider a regime relevant for the relativistic heavy ion collisions, α seB << T 2 << eB, so that thermal excitations of light quarks are restricted to the lowest Landau level (LLL) states. In the vanishing light-quark mass limit, we find κ LO ⊥ ∝ α 2 sTeB in the leading order that arises from screened Coulombmore » scatterings with (1+1)-dimensional LLL quarks, while κ ∥ gets no contribution from the scatterings with LLL quarks due to kinematic restrictions. We show that the first nonzero leading order contributions to κ LO ∥ come from the two separate effects: 1) the screened Coulomb scatterings with thermal gluons, and 2) a finite light-quark mass m q. The former leads to κ LO,gluon ∥ ∝ α 2 sT 3 and the latter to κ LO,massive ∥ ∝ α s(α seB) 1/2m 2 q. Based on our results, we propose a new scenario for the large value of heavy-quark elliptic flow observed in RHIC and LHC. Namely, when κ ⊥ >> κ ∥, an anisotropy in drag forces gives rise to a sizable amount of the heavy-quark elliptic flow even if heavy quarks do not fully belong to an ellipsoidally expanding background fluid.« less

Heavy quark diffusion in strong magnetic fields at weak coupling and implications for elliptic flow

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fukushima, Kenji; Hattori, Koichi; Yee, Ho -Ung

In this paper, we compute the momentum diffusion coefficients of heavy quarks, κ ∥ and κ ⊥, in a strong magnetic field B along the directions parallel and perpendicular to B, respectively, at the leading order in QCD coupling constant α s. We consider a regime relevant for the relativistic heavy ion collisions, α seB << T 2 << eB, so that thermal excitations of light quarks are restricted to the lowest Landau level (LLL) states. In the vanishing light-quark mass limit, we find κ LO ⊥ ∝ α 2 sTeB in the leading order that arises from screened Coulombmore » scatterings with (1+1)-dimensional LLL quarks, while κ ∥ gets no contribution from the scatterings with LLL quarks due to kinematic restrictions. We show that the first nonzero leading order contributions to κ LO ∥ come from the two separate effects: 1) the screened Coulomb scatterings with thermal gluons, and 2) a finite light-quark mass m q. The former leads to κ LO,gluon ∥ ∝ α 2 sT 3 and the latter to κ LO,massive ∥ ∝ α s(α seB) 1/2m 2 q. Based on our results, we propose a new scenario for the large value of heavy-quark elliptic flow observed in RHIC and LHC. Namely, when κ ⊥ >> κ ∥, an anisotropy in drag forces gives rise to a sizable amount of the heavy-quark elliptic flow even if heavy quarks do not fully belong to an ellipsoidally expanding background fluid.« less

An inductorless active mixer using stacked nMOS/pMOS configuration and LO shaping technique

NASA Astrophysics Data System (ADS)

Guo, Benqing; Chen, Jun; Wang, Xuebing; Chen, Hongpeng

2018-04-01

In this paper, a CMOS active down-conversion mixer is presented for wideband applications. Specifically, a LO generation chain is suggested to convert AC LO signal to shaped trapezoid burst, which reduces the sinusoidal LO power level requirement by the mixer. The current-reuse technique by stacked nMOS/pMOS architecture is used to save the power consumption of the circuit. Moreover, this complementary configuration is also employed to compensate second-order nonlinearity of the circuit. Implemented in a 0.18-μm CMOS process, post-simulations show that, driven by only ‑10 dBm sinusoidal LO signal, the proposed inductorless mixer provides a maximal conversion gain of 15.7 dB and a noise figure (NF) of 9.1-12 dB across RF input frequency range 0.5-1.6 GHz. The IIP3 and IP1dB of 3.5 dBm and ‑4.8 dBm are obtained, respectively. The mixer core only consumes 3.6 mW from a 1.8-V supply.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wollaber, Allan Benton; Park, HyeongKae; Lowrie, Robert Byron

Moment-based acceleration via the development of “high-order, low-order” (HO-LO) algorithms has provided substantial accuracy and efficiency enhancements for solutions of the nonlinear, thermal radiative transfer equations by CCS-2 and T-3 staff members. Accuracy enhancements over traditional, linearized methods are obtained by solving a nonlinear, timeimplicit HO-LO system via a Jacobian-free Newton Krylov procedure. This also prevents the appearance of non-physical maximum principle violations (“temperature spikes”) associated with linearization. Efficiency enhancements are obtained in part by removing “effective scattering” from the linearized system. In this highlight, we summarize recent work in which we formally extended the HO-LO radiation algorithm to includemore » operator-split radiation-hydrodynamics.« less

On a realization of { β}-expansion in QCD

NASA Astrophysics Data System (ADS)

Mikhailov, S. V.

2017-04-01

We suggest a simple algebraic approach to fix the elements of the { β}-expansion for renormalization group invariant quantities, which uses additional degrees of freedom. The approach is discussed in detail for N2LO calculations in QCD with the MSSM gluino — an additional degree of freedom. We derive the formulae of the { β}-expansion for the nonsinglet Adler D-function and Bjorken polarized sum rules in the actual N3LO within this quantum field theory scheme with the MSSM gluino and the scheme with the second additional degree of freedom. We discuss the properties of the { β}-expansion for higher orders considering the N4LO as an example.

Development of Thread-compatible Open Source Stack

NASA Astrophysics Data System (ADS)

Zimmermann, Lukas; Mars, Nidhal; Schappacher, Manuel; Sikora, Axel

2017-07-01

The Thread protocol is a recent development based on 6LoWPAN (IPv6 over IEEE 802.15.4), but with extensions regarding a more media independent approach, which - additionally - also promises true interoperability. To evaluate and analyse the operation of a Thread network a given open source 6LoWPAN stack for embedded devices (emb::6) has been extended in order to comply with the Thread specification. The implementation covers Mesh Link Establishment (MLE) and network layer functionality as well as 6LoWPAN mesh under routing mechanism based on MAC short addresses. The development has been verified on a virtualization platform and allows dynamical establishment of network topologies based on Thread’s partitioning algorithm.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Alarcón, Jose Manuel; Du, Dechuan; Klein, Nico

Here, we present a systematic study of neutron-proton scattering in Nuclear Lattice Effective Field Theory (NLEFT), in terms of the computationally efficient radial Hamiltonian method. Our leading-order (LO) interaction consists of smeared, local contact terms and static one-pion exchange. We show results for a fully non-perturbative analysis up to next-to-next-to-leading order (NNLO), followed by a perturbative treatment of contributions beyond LO. The latter analysis anticipates practical Monte Carlo simulations of heavier nuclei. We explore how our results depend on the lattice spacing a, and estimate sources of uncertainty in the determination of the low-energy constants of the next-to-leading-order (NLO) two-nucleonmore » force. We give results for lattice spacings ranging from a = 1.97 fm down to a = 0.98 fm, and discuss the effects of lattice artifacts on the scattering observables. At a = 0.98 fm, lattice artifacts appear small, and our NNLO results agree well with the Nijmegen partial-wave analysis for S-wave and P-wave channels. We expect the peripheral partial waves to be equally well described once the lattice momenta in the pion-nucleon coupling are taken to coincide with the continuum dispersion relation, and higher-order (N 3LO) contributions are included. Finally, we stress that for center-of-mass momenta below 100 MeV, the physics of the two-nucleon system is independent of the lattice spacing.« less

Protective effect of lavender oil on scopolamine induced cognitive deficits in mice and H2O2 induced cytotoxicity in PC12 cells.

PubMed

Xu, Pan; Wang, Kezhu; Lu, Cong; Dong, Liming; Gao, Li; Yan, Ming; Aibai, Silafu; Liu, Xinmin

2016-12-04

Lavender essential oil (LO), an aromatic liquid extracted from Lavandula angustifolia Mill., has been traditionally used in the treatments of many nervous system diseases, and recently LO also reported to be effective for the Alzheimer's disease (AD). The improvement effect of lavender oil (LO) on the scopolamine-induced cognitive deficits in mice and H 2 O 2 induced cytotoxicity in PC12 cells have been evaluated. The relevant mechanism was also researched from the perspective of antioxidant effect and cholinergic system modulation. Cognitive deficits were induced in C57BL/6J mice treated with scopolamine (1mg/kg, i.p.) and were assessed by Morris water maze (MWM) and step-through passive avoidance tests. Then their hippocampus were removed for biochemical assays (acetylcholinesterase (AChE), superoxide dismutase (SOD), glutathione peroxidase (GPX) and malondialdehyde (MDA)). In vitro, the cytotoxicity were induced by 4h exposure to H 2 O 2 in PC12 and evaluated by cell viability (MTT), lactate dehydrogenase (LDH) level, nitric oxide (NO) release, reactive oxygen species (ROS) production and mitochondrial membrane potential (MMP). The results demonstrated that LO (100mg/kg) could improve the cognitive performance of scopolamine induced mice in behavioral tests. Meanwhile, it significantly decreased the AChE activity, MDA level, and increase SOD and GPX activities of the model. Moreover, LO (12μg/mL) protected PC12 cells from H 2 O 2 induced cytotoxicity by reducing LDH, NO release, intracellular ROS accumulation and MMP loss. It was suggested that LO could show neuroprotective effect in AD model in vivo (scopolamine-treated mice) and in vitro (H 2 O 2 induced PC12 cells) via modulating oxidative stress and AChE activity. Copyright © 2016. Published by Elsevier Ireland Ltd.

Jet production in the CoLoRFulNNLO method: Event shapes in electron-positron collisions

NASA Astrophysics Data System (ADS)

Del Duca, Vittorio; Duhr, Claude; Kardos, Adam; Somogyi, Gábor; Szőr, Zoltán; Trócsányi, Zoltán; Tulipánt, Zoltán

2016-10-01

We present the CoLoRFulNNLO method to compute higher order radiative corrections to jet cross sections in perturbative QCD. We apply our method to the computation of event shape observables in electron-positron collisions at NNLO accuracy and validate our code by comparing our predictions to previous results in the literature. We also calculate for the first time jet cone energy fraction at NNLO.

The use of a block diagram simulation language for rapid model prototyping

NASA Technical Reports Server (NTRS)

Whitlow, Jonathan E.

1995-01-01

The research performed this summer focussed on the development of a predictive model for the loading of liquid oxygen (LO2) into the external tank (ET) of the shuttle prior to launch. A predictive model can greatly aid the operational personnel since instrumentation aboard the orbiter and ET is limited due to weight constraints. The model, which focuses primarily on the orbiter section of the system was developed using a block diagram based simulation language known as VisSim. Simulations were run on LO2 loading data for shuttle flights STS50 and STS55 and the model was demonstrated to accurately predict the sensor data recorded for these flights. As a consequence of the simulation results, it can be concluded that the software tool can be very useful for rapid prototyping of complex models.

Inclusive neutrino scattering off the deuteron at low energies in chiral effective field theory

DOE PAGES

Baroni, A.; Schiavilla, R.

2017-07-19

Cross sections for inclusive neutrino scattering off deuteron induced by neutral and charge-changing weak currents are calculated from threshold up to 150 MeV energies in a chiral effective field theory including high orders in the power counting. The contributions beyond leading order (LO) in the weak current are found to be small, and increase the cross sections obtained with the LO transition operators by a couple of percent over the whole energy range (0--150) MeV. Furthermore, the cutoff dependence is negligible, and the predicted cross sections are within ~2% of, albeit consistently larger than, corresponding predictions obtained in conventional meson-exchangemore » frameworks.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Boroun, G. R., E-mail: grboroun@gmail.com, E-mail: boroun@razi.ac.ir; Zarrin, S.; Dadfar, S.

We evaluate the non-singlet spin-dependent structure function g{sub 1}{sup NS} at leading order (LO) and next-to-leading order (NLO) by using the Laplace-transform technique and method of characteristics and also obtain its first moment at NLO. The polarized non-singlet structure function results are compared with the data from HERMES (A. Airapetian et al., Phys. Rev. D 75, 012007 (2007)) and E143 (K. Abe et al. (E143 Collab.), Phys. Rev. D 58, 112003 (1998)) at LO and NLO analyses and the first-moment the result at NLO is compared with the result of the NLO GRSV2000 fit. Considering the solution, this method ismore » valid at low- and large-x regions.« less

Preliminary Assessment of Using Gelled and Hybrid Propellant Propulsion for VTOL/SSTO Launch Systems

NASA Technical Reports Server (NTRS)

Palaszewski, Bryan; OLeary, Robert; Pelaccio, Dennis G.

1998-01-01

A novel, reusable, Vertical-Takeoff-and-Vertical-Takeoff-and-Landing, Single-Stage-to-Orbit (VTOL/SSTO) launch system concept, named AUGMENT-SSTO, is presented in this paper to help quantify the advantages of employing gelled and hybrid propellant propulsion system options for such applications. The launch vehicle system concept considered uses a highly coupled, main high performance liquid oxygen/liquid hydrogen (LO2/LH2) propulsion system, that is used only for launch, while a gelled or hybrid propellant propulsion system auxiliary propulsion system is used during final orbit insertion, major orbit maneuvering, and landing propulsive burn phases of flight. Using a gelled or hybrid propellant propulsion system for major orbit maneuver burns and landing has many advantages over conventional VTOL/SSTO concepts that use LO2/LH2 propulsion system(s) burns for all phases of flight. The applicability of three gelled propellant systems, O2/H2/Al, O2/RP-1/Al, and NTO/MMH/Al, and a state-of-the-art (SOA) hybrid propulsion system are examined in this study. Additionally, this paper addresses the applicability of a high performance gelled O2/H2 propulsion system to perform the primary, as well as the auxiliary propulsion system functions of the vehicle.

Cryogenic propulsion for the Titan Orbiter Polar Surveyor (TOPS) mission

NASA Astrophysics Data System (ADS)

Mustafi, S.; DeLee, C.; Francis, J.; Li, X.; McGuinness, D.; Nixon, C. A.; Purves, L.; Willis, W.; Riall, S.; Devine, M.; Hedayat, A.

2016-03-01

Liquid hydrogen (LH2) and liquid oxygen (LO2) cryogenic propellants can dramatically enhance NASA's ability to explore the solar system due to their superior specific impulse (Isp) capability. Although these cryogenic propellants can be challenging to manage and store, they allow significant mass advantages over traditional hypergolic propulsion systems and are therefore enabling for many planetary science missions. New cryogenic storage techniques such as subcooling and the use of advanced insulation and low thermal conductivity support structures will allow for the long term storage and use of cryogenic propellants for solar system exploration and hence allow NASA to deliver more payloads to targets of interest, launch on smaller and less expensive launch vehicles, or both. These new cryogenic storage technologies were implemented in a design study for the Titan Orbiter Polar Surveyor (TOPS) mission, with LH2 and LO2 as propellants, and the resulting spacecraft design was able to achieve a 43% launch mass reduction over a TOPS mission, that utilized a traditional hypergolic propulsion system with mono-methyl hydrazine (MMH) and nitrogen tetroxide (NTO) propellants. This paper describes the cryogenic propellant storage design for the TOPS mission and demonstrates how these cryogenic propellants are stored passively for a decade-long Titan mission that requires the cryogenics propellants to be stored for 8.5 years.

Self-Referenced Smartphone-Based Nanoplasmonic Imaging Platform for Colorimetric Biochemical Sensing.

PubMed

Wang, Xinhao; Chang, Te-Wei; Lin, Guohong; Gartia, Manas Ranjan; Liu, Gang Logan

2017-01-03

Colorimetric sensors usually suffer due to errors from variation in light source intensity, the type of light source, the Bayer filter algorithm, and the sensitivity of the camera to incoming light. Here, we demonstrate a self-referenced portable smartphone-based plasmonic sensing platform integrated with an internal reference sample along with an image processing method to perform colorimetric sensing. Two sensing principles based on unique nanoplasmonics enabled phenomena from a nanostructured plasmonic sensor, named as nanoLCA (nano Lycurgus cup array), were demonstrated here for colorimetric biochemical sensing: liquid refractive index sensing and optical absorbance enhancement sensing. Refractive indices of colorless liquids were measured by simple smartphone imaging and color analysis. Optical absorbance enhancement in the colorimetric biochemical assay was achieved by matching the plasmon resonance wavelength with the chromophore's absorbance peak wavelength. Such a sensing mechanism improved the limit of detection (LoD) by 100 times in a microplate reader format. Compared with a traditional colorimetric assay such as urine testing strips, a smartphone plasmon enhanced colorimetric sensing system provided 30 times improvement in the LoD. The platform was applied for simulated urine testing to precisely identify the samples with higher protein concentration, which showed potential point-of-care and early detection of kidney disease with the smartphone plasmonic resonance sensing system.

100-lbf LO2/CH4 RCS Thruster Testing and Validation

NASA Technical Reports Server (NTRS)

Barnes, Frank; Cannella, Matthew; Gomez, Carlos; Hand, Jeffrey; Rosenberg, David

2009-01-01

100 pound thrust liquid Oxygen-Methane thruster sized for RCS (Reaction Control System) applications. Innovative Design Characteristics include: a) Simple compact design with minimal part count; b) Gaseous or Liquid propellant operation; c) Affordable and Reusable; d) Greater flexibility than existing systems; e) Part of NASA'S study of "Green Propellants." Hot-fire testing validated performance and functionality of thruster. Thruster's dependence on mixture ratio has been evaluated. Data has been used to calculate performance parameters such as thrust and Isp. Data has been compared with previous test results to verify reliability and repeatability. Thruster was found to have an Isp of 131 s and 82 lbf thrust at a mixture ratio of 1.62.

Bile Stress Response in Listeria monocytogenes LO28: Adaptation, Cross-Protection, and Identification of Genetic Loci Involved in Bile Resistance

PubMed Central

Begley, Máire; Gahan, Cormac G. M.; Hill, Colin

2002-01-01

Bile is one of many barriers that Listeria monocytogenes must overcome in the human gastrointestinal tract in order to infect and cause disease. We demonstrated that stationary-phase cultures of L. monocytogenes LO28 were able to tolerate concentrations of bovine, porcine, and human bile and bile acids well in excess of those encountered in vivo. Strain LO28 was relatively bile resistant compared with other clinical isolates of L. monocytogenes, as well as with Listeria innocua, Salmonella enterica serovar Typhimurium LT2, and Lactobacillus sakei. While exponential-phase L. monocytogenes LO28 cells were exquisitely sensitive to unconjugated bile acids, prior adaptation to sublethal levels of bile acids or heterologous stresses, such as acid, heat, salt, or sodium dodecyl sulfate (SDS), significantly enhanced bile resistance. This adaptive response was independent of protein synthesis, and in the cases of bile and SDS adaptation, occurred in seconds. In order to identify genetic loci involved in the bile tolerance phenotype of L. monocytogenes LO28, transposon (Tn917) and plasmid (pORI19) integration banks were screened for bile-sensitive mutants. The disrupted genes included a homologue of the capA locus required for capsule formation in Bacillus anthracis; a gene encoding the transcriptional regulator ZurR; a homologue of an Escherichia coli gene, lytB, involved in isoprenoid biosynthesis; a gene encoding a homologue of the Bacillus subtilis membrane protein YxiO; and a gene encoding an amino acid transporter with a putative role in pH homeostasis, gadE. Interestingly, all of the identified loci play putative roles in maintenance of the cell envelope or in stress responses. PMID:12450822

Effect of neurosteroids on a model lipid bilayer including cholesterol: An Atomic Force Microscopy study.

PubMed

Sacchi, Mattia; Balleza, Daniel; Vena, Giulia; Puia, Giulia; Facci, Paolo; Alessandrini, Andrea

2015-05-01

Amphiphilic molecules which have a biological effect on specific membrane proteins, could also affect lipid bilayer properties possibly resulting in a modulation of the overall membrane behavior. In light of this consideration, it is important to study the possible effects of amphiphilic molecule of pharmacological interest on model systems which recapitulate some of the main properties of the biological plasma membranes. In this work we studied the effect of a neurosteroid, Allopregnanolone (3α,5α-tetrahydroprogesterone or Allo), on a model bilayer composed by the ternary lipid mixture DOPC/bSM/chol. We chose ternary mixtures which present, at room temperature, a phase coexistence of liquid ordered (Lo) and liquid disordered (Ld) domains and which reside near to a critical point. We found that Allo, which is able to strongly partition in the lipid bilayer, induces a marked increase in the bilayer area and modifies the relative proportion of the two phases favoring the Ld phase. We also found that the neurosteroid shifts the miscibility temperature to higher values in a way similarly to what happens when the cholesterol concentration is decreased. Interestingly, an isoform of Allo, isoAllopregnanolone (3β,5α-tetrahydroprogesterone or isoAllo), known to inhibit the effects of Allo on GABAA receptors, has an opposite effect on the bilayer properties. Copyright © 2015 Elsevier B.V. All rights reserved.

Tritium β decay in chiral effective field theory

DOE PAGES

Baroni, A.; Girlanda, L.; Kievsky, A.; ...

2016-08-18

We evaluate the Fermi and Gamow-Teller (GT) matrix elements in tritiummore » $$\\beta$$-decay by including in the charge-changing weak current the corrections up to one loop recently derived in nuclear chiral effective field theory ($$\\chi$$ EFT). The trinucleon wave functions are obtained from hyperspherical-harmonics solutions of the Schroedinger equation with two- and three-nucleon potentials corresponding to either $$\\chi$$ EFT (the N3LO/N2LO combination) or meson-exchange phenomenology (the AV18/UIX combination). We find that contributions due to loop corrections in the axial current are, in relative terms, as large as (and in some cases, dominate) those from one-pion exchange, which nominally occur at lower order in the power counting. Furthermore, we also provide values for the low-energy constants multiplying the contact axial current and three-nucleon potential, required to reproduce the experimental GT matrix element and trinucleon binding energies in the N3LO/N2LO and AV18/UIX calculations.« less

XYZ-SU3 breakings from Laplace sum rules at higher orders

NASA Astrophysics Data System (ADS)

Albuquerque, R.; Narison, S.; Rabetiarivony, D.; Randriamanatrika, G.

2018-06-01

We present new compact integrated expressions of SU3 breaking corrections to QCD spectral functions of heavy-light molecules and four-quark XY Z-like states at lowest order (LO) of perturbative (PT) QCD and up to d = 8 condensates of the Operator Product Expansion (OPE). Including next-to-next-to-leading order (N2LO) PT corrections in the chiral limit and next-to-leading order (NLO) SU3 PT corrections, which we have estimated by assuming the factorization of the four-quark spectral functions, we improve previous LO results for the XY Z-like masses and decay constants from QCD spectral sum rules (QSSR). Systematic errors are estimated from a geometric growth of the higher order PT corrections and from some partially known d = 8 nonperturbative contributions. Our optimal results, based on stability criteria, are summarized in Tables 18-21 while the 0++ and 1++ channels are compared with some existing LO results in Table 22. One can note that, in most channels, the SU3 corrections on the meson masses are tiny: ≤ 10% (respectively ≤ 3%) for the c (respectively b)-quark channel but can be large for the couplings ( ≤ 20%). Within the lowest dimension currents, most of the 0++ and 1++ states are below the physical thresholds while our predictions cannot discriminate a molecule from a four-quark state. A comparison with the masses of some experimental candidates indicates that the 0++ X(4500) might have a large D¯s0∗D s0∗ molecule component while an interpretation of the 0++ candidates as four-quark ground states is not supported by our findings. The 1++ X(4147) and X(4273) are compatible with the D¯s∗D s, D¯s0∗D s1 molecules and/or with the axial-vector Ac four-quark ground state. Our results for the 0‑±, 1‑± and for different beauty states can be tested in the future data. Finally, we revisit our previous estimates1 for the D¯0∗D 0∗ and D¯0∗D 1 and present new results for the D¯1D1.

Performance evaluation and optimization of multiband phase-modulated radio over IsOWC link with balanced coherent homodyne detection

NASA Astrophysics Data System (ADS)

Zong, Kang; Zhu, Jiang

2018-04-01

In this paper, we present a multiband phase-modulated (PM) radio over intersatellite optical wireless communication (IsOWC) link with balanced coherent homodyne detection. The proposed system can provide the transparent transport of multiband radio frequency (RF) signals with higher linearity and better receiver sensitivity than intensity modulated with direct detection (IM/DD) system. The expressions of RF gain, noise figure (NF) and third-order spurious-free dynamic range (SFDR) are derived considering the third-order intermodulation product and amplifier spontaneous emission (ASE) noise. The optimal power of local oscillator (LO) optical signal is also derived theoretically. Numerical results for RF gain, NF and third-order SFDR are given for demonstration. Results indicate that the gain of the optical preamplifier and the power of LO optical signal should be optimized to obtain the satisfactory performance.

Pion-less effective field theory for real and lattice nuclei

NASA Astrophysics Data System (ADS)

Bansal, Aaina; Binder, Sven; Ekström, Andreas; Hagen, Gaute; Papenbrock, Thomas

2017-09-01

We compute the medium-heavy nuclei 16O and 40Ca using pion-less effective field theory (EFT) at leading order (LO) and next-to-leading order (NLO). The low-energy coefficients of the EFT Hamiltonian are adjusted to A = 2 , 3 nuclei data from experiments, or alternatively to data from lattice QCD at unphysical pion mass mπ = 806 MeV. The EFT is implemented through discrete variable representation of finite harmonic oscillator basis. This approach ensures rapid convergence with respect to the size of the model space and allows us to compute heavier atomic and lattice nuclei. The atomic nuclei 16O and 40Ca are bound with respect to decay into alpha particles at NLO, but not at LO.

[Modeling of linoleyl hydroxamic acid influence on lipoxygenases in vitro].

PubMed

Skaterna, T D; Kopich, V M; Tserniuk, V M; Kharchenko, O V

2009-01-01

5-Lipoxygenase (5-LO) (1.13.11.12) demonstrates its activity in membrane-associated state. A system in vitro with increasing quantity of mixed micelle of nonionic detergent Lubrol PX and substrate--linoleic acid (LA) was used for understanding of 5-LO catalytic activity mechanism, which depends on the membrane environment. Physical parameters of micelles with molar ratio LA-Lubrol PX = 0.3:1 and micelles with 5-LO inhibitor--linoleyl hydroxamic acid (LHA), LA and Lubrol PX (0.03:0.3:1) were characterized by gel-filtration method on Sephadex G-200. It was determined, that Stock's radii were 4.83-5.79 nm for micelles with total LA--50-2000 microM and average molecular mass--177 000-212 000 Da. The presence of 10 microM LHA has no influence on physical parameters of the system. Influence of LHA on kinetic parameters of LA oxidation reaction catalized by potato tubers 5-LO in characterized mixed micelle system was also studied. Substrate dependences curves of 5-LO LA oxidation steady-state rates under conditions of the mixed micelle with ratio LA-lubrol PX = 0.3:1, LHA-LA-Lubrol PX = 0.03:0.3:1 and LHA-LA-Lubrol PX = 0.12:0.3:1 were typical of the substrate inhibition. The presence of inhibitor had no effect on the number of additional substrate molecules--LA which contact with enzyme-substrate complex and decreased V(max) essentially. To predict further inhibitor transformation in the cell the influence of 13-hydroperoxy- and 13-hydroxy LHA on potato tubers 5-LO and porcine leucocyte 12-LO was investigated. It was established that LHA oxidized forms displayed as no less effective inhibitors of the analyzed enzymes; 13-hydroperoxy LHA efficiency increased by an order (IC50 was 0.7 microM) for 12-LO. The possibility of 5-LO to oxidize inhibitor LHA under 50 microM phosphatidic acid at pH 5.0 was demonstrated.

Spice phenolics inhibit human PMNL 5-lipoxygenase.

PubMed

Prasad, N Satya; Raghavendra, R; Lokesh, B R; Naidu, K Akhilender

2004-06-01

A wide variety of phenolic compounds and flavonoids present in spices possess potent antioxidant, antimutagenic and anticarcinogenic activities. We examined whether 5-lipoxygenase (5-LO), the key enzyme involved in biosynthesis of leukotrienes is a possible target for the spices. Effect of aqueous extracts of turmeric, cloves, pepper, chili, cinnamon, onion and also their respective active principles viz., curcumin, eugenol, piperine, capsaicin, cinnamaldehyde, quercetin, and allyl sulfide were tested on human PMNL 5-LO activity by spectrophotomeric and HPLC methods. The formation of 5-LO product 5-HETE was significantly inhibited in a concentration-dependent manner with IC(50) values of 0.122-1.44 mg for aqueous extracts of spices and 25-83 microM for active principles, respectively. The order of inhibitory activity was of quercetin>eugenol>curcumin>cinnamaldehyde>piperine>capsaicin>allyl sulfide. Quercetin, eugenol and curcumin with one or more phenolic ring and methoxy groups in their structure showed high inhibitory effect, while the non-phenolic spice principle allyl sulfide showed least inhibitory effect on 5-LO. The inhibitory effect of quercetin, curcumin and eugenol was similar to that of synthetic 5-LO inhibitors-phenidone and NDGA. Moreover, the inhibitory potency of aqueous extracts of spice correlated with the active principles of their respective spices. The synergistic or antagonistic effect of mixtures of spice active principles and spice extracts were investigated and all the combinations of spice active principles/extracts exerted synergistic effect in inhibiting 5-LO activity. These findings clearly suggest that phenolic compounds present in spices might have physiological role in modulating 5-LO pathway.

Spark Ignition Characteristics of a LO2/LCH4 Engine at Altitude Conditions

NASA Technical Reports Server (NTRS)

Kleinhenz, Julie; Sarmiento, Charles; Marshall, William

2012-01-01

The use of non-toxic propellants in future exploration vehicles would enable safer, more cost effective mission scenarios. One promising "green" alternative to existing hypergols is liquid methane/liquid oxygen. To demonstrate performance and prove feasibility of this propellant combination, a 100lbf LO2/LCH4 engine was developed and tested under the NASA Propulsion and Cryogenic Advanced Development (PCAD) project. Since high ignition energy is a perceived drawback of this propellant combination, a test program was performed to explore ignition performance and reliability versus delivered spark energy. The sensitivity of ignition to spark timing and repetition rate was also examined. Three different exciter units were used with the engine's augmented (torch) igniter. Propellant temperature was also varied within the liquid range. Captured waveforms indicated spark behavior in hot fire conditions was inconsistent compared to the well-behaved dry sparks (in quiescent, room air). The escalating pressure and flow environment increases spark impedance and may at some point compromise an exciter.s ability to deliver a spark. Reduced spark energies of these sparks result in more erratic ignitions and adversely affect ignition probability. The timing of the sparks relative to the pressure/flow conditions also impacted the probability of ignition. Sparks occurring early in the flow could trigger ignition with energies as low as 1-6mJ, though multiple, similarly timed sparks of 55-75mJ were required for reliable ignition. An optimum time interval for spark application and ignition coincided with propellant introduction to the igniter and engine. Shifts of ignition timing were manifested by changes in the characteristics of the resulting ignition.

Transverse momentum dependent (TMD) parton distribution functions generated in the modified DGLAP formalism based on the valence-like distributions

NASA Astrophysics Data System (ADS)

Hosseinkhani, H.; Modarres, M.; Olanj, N.

2017-07-01

Transverse momentum dependent (TMD) parton distributions, also referred to as unintegrated parton distribution functions (UPDFs), are produced via the Kimber-Martin-Ryskin (KMR) prescription. The GJR08 set of parton distribution functions (PDFs) which are based on the valence-like distributions is used, at the leading order (LO) and the next-to-leading order (NLO) approximations, as inputs of the KMR formalism. The general and the relative behaviors of the generated TMD PDFs at LO and NLO and their ratios in a wide range of the transverse momentum values, i.e. kt2 = 10, 102, 104 and 108GeV2 are investigated. It is shown that the properties of the parent valence-like PDFs are imprinted on the daughter TMD PDFs. Imposing the angular ordering constraint (AOC) leads to the dynamical variable limits on the integrals which in turn increase the contributions from the lower scales at lower kt2. The results are compared with our previous studies based on the MSTW2008 input PDFs and it is shown that the present calculation gives flatter TMD PDFs. Finally, a comparison of longitudinal structure function (FL) is made by using the produced TMD PDFs and those that were generated through the MSTW2008-LO PDF from our previous work and the corresponding data from H1 and ZEUS collaborations and a reasonable agreement is found.

Small, high-pressure liquid oxygen turbopump

NASA Technical Reports Server (NTRS)

Csomor, A.; Sutton, R.

1977-01-01

A small, high-pressure, liquid oxygen turbopump was designed, fabricated, and tested. The pump was of a single-stage, centrifugal type; power to the pump was supplied by a single-stage, partial emission, axial-impulse turbine. Design conditions included an operating speed of 70,000 rpm, pump discharge pressure of 2977 N/sq cm (4318 psia), and a pump flowrate of 16.4 kg/s (36.21 lb/sec). The turbine was propelled by LO2/LH2 combustion products at 1041 K (1874 R) inlet temperature, and at a design pressure ratio of 1.424. The approaches used in the detail analysis and design of the turbopump are described, and fabrication methods are discussed. Data obtained from gas generator tests, turbine performance calibration, and turbopump testing are presented.

Space Shuttle Orbiter Atlantis Liquid Oxygen Prevalve Detent Roller Cracking Investigation

NASA Technical Reports Server (NTRS)

Holleman, Elizabeth; Eddleman, David; Richard, James; Jacobs, Rebecca

2008-01-01

During routine inspections of the Space Shuttle's Main Propulsion System (MPS) Liquid Oxygen (LO2) pre-valve, the mechanism provided to maintain the valve in the open position was found cracked. The mechanism is a Vespel roller held against the valve visor by a stack of Belleville springs. The roller has been found cracked 3 times. All three instances were in the same valve in the same location. There are 6 pre-valves on each orbiter, and only one has exhibited this problem. Every-flight inspections were instituted and the rollers were found to be cracked after only one flight. Engineers at Marshall Space Flight Center, Johnson Space Center and Kennedy Space Center worked together to determine a solution. There were several possible contributors to the failure: a mis-aligned visor, an out of specification edge with a sharp radius, an out of specification tolerance stack up of a Belleville spring stack that caused un-predicted loads on the Vespel SP-21 roller, and a dimple machined into the side of the roller to indicate LO2 compatibility that created a stress riser. The detent assembly was removed and replaced with parts that were on the low-side of the tolerance stack up to eliminate the potential for high loads on the detent roller. After one flight, the roller was inspected and showed fewer signs of wear and no cracks.

Space Shuttle Orbiter Atlantis Liquid Oxygen Pre-Valve Detent Roller Cracking Investigation

NASA Technical Reports Server (NTRS)

Holleman, Elizabeth; Eddleman, David; Jacobs, Rebecca; Richard, James

2008-01-01

During routine inspections of the Space Shuttle s Main Propulsion System Liquid Oxygen (LO2) pre-valve, the mechanism provided to maintain the valve in the open position was found cracked. The mechanism is a Vespel roller held against the valve visor by a stack of Belleville springs. The roller has been found cracked 3 times. All three instances were in the same valve in the same location. There are 6 pre-valves on each orbiter, and only one has exhibited this problem. Every-flight inspections were instituted and the rollers were found to be cracked after only one flight. Engineers at Marshall Space Flight Center, Johnson Space Center, and Kennedy Space Center worked together to determine a solution. There were several possible contributors to the failure: a misaligned visor, an out-of-specification edge with a sharp radius, an out-of-specification tolerance stack up of a Belleville spring stack that caused un-predicted loads on the Vespel SP-21 roller, and a dimple machined into the side of the roller to indicate LO2 compatibility that created a stress riser. The detent assembly was removed and replaced with parts that were on the low side of the tolerance stack up to eliminate the potential for high loads on the detent roller. After one flight, the roller was inspected and showed fewer signs of wear and no cracks.

Analysis of 100-lb(sub f) (445-N) LO2-LCH4 Reaction Control Engine Impulse Bit Performance

NASA Technical Reports Server (NTRS)

Marshall, William M.; Klenhenz, Julie E.

2012-01-01

Recently, liquid oxygen-liquid methane (LO2-LCH4) has been considered as a potential green propellant alternative for future exploration missions. The Propulsion and Cryogenic Advanced Development (PCAD) project was tasked by NASA to develop this propulsion combination to enable safe and cost-effective exploration missions. To date, limited experience with such combinations exist, and as a result a comprehensive test program is critical to demonstrating with the viability of implementing such a system. The NASA Glenn Research Center conducted a test program of a 100-lbf (445-N) reaction control engine (RCE) at the Center s Altitude Combustion Stand (ACS), focusing on altitude testing over a wide variety of operational conditions. The ACS facility includes unique propellant conditioning feed systems (PCFS), which allow precise control of propellant inlet conditions to the engine. Engine performance as a result of these inlet conditions was examined extensively during the test program. This paper is a companion to the previous specific impulse testing paper, and discusses the pulsed-mode operation portion of testing, with a focus on minimum impulse bit (MIB) and repeatable pulse performance. The engine successfully demonstrated target MIB performance at all conditions, as well as successful demonstration of repeatable pulse widths. Some anomalous conditions experienced during testing are also discussed, including a double pulse phenomenon, which was not noted in previous test programs for this engine.

High Pressure Composite Overwrapped Pressure Vessel (COPV) Development Tests at Cryogenic Temperatures

NASA Technical Reports Server (NTRS)

Ray, David M.; Greene, Nathanael J.; Revilock, Duane; Sneddon, Kirk; Anselmo, Estelle

2008-01-01

Development tests were conducted to evaluate the performance of 2 COPV designs at cryogenic temperatures. This allows for risk reductions for critical components for a Gaseous Helium (GHe) Pressurization Subsystem for an Advanced Propulsion System (APS) which is being proposed for NASA s Constellation project and future exploration missions. It is considered an advanced system since it uses Liquid Methane (LCH4) as the fuel and Liquid Oxygen (LO2) as the oxidizer for the propellant combination mixture. To avoid heating of the propellants to prevent boil-off, the GHe will be stored at subcooled temperatures equivalent to the LO2 temperature. Another advantage of storing GHe at cryogenic temperatures is that more mass of the pressurized GHe can be charged in to a vessel with a smaller volume, hence a smaller COPV, and this creates a significant weight savings versus gases at ambient temperatures. The major challenge of this test plan is to verify that a COPV can safely be used for spacecraft applications to store GHe at a Maximum Operating Pressure (MOP) of 4,500 psig at 140R to 160R (-320 F to -300 F). The COPVs for these tests were provided by ARDE , Inc. who developed a resin system to use at cryogenic conditions and has the capabilities to perform high pressure testing with LN2.

Recent Advances and Applications in Cryogenic Propellant Densification Technology

NASA Technical Reports Server (NTRS)

Tomsik, Thomas M.

2000-01-01

This purpose of this paper is to review several historical cryogenic test programs that were conducted at the NASA Glenn Research Center (GRC), Cleveland, Ohio over the past fifty years. More recently these technology programs were intended to study new and improved denser forms of liquid hydrogen (LH2) and liquid oxygen (LO2) cryogenic rocket fuels. Of particular interest are subcooled cryogenic propellants. This is due to the fact that they have a significantly higher density (eg. triple-point hydrogen, slush etc.), a lower vapor pressure and improved cooling capacity over the normal boiling point cryogen. This paper, which is intended to be a historical technology overview, will trace the past and recent development and testing of small and large-scale propellant densification production systems. Densifier units in the current GRC fuels program, were designed and are capable of processing subcooled LH2 and L02 propellant at the X33 Reusable Launch Vehicle (RLV) scale. One final objective of this technical briefing is to discuss some of the potential benefits and application which propellant densification technology may offer the industrial cryogenics production and end-user community. Density enhancements to cryogenic propellants (LH2, LO2, CH4) in rocket propulsion and aerospace application have provided the opportunity to either increase performance of existing launch vehicles or to reduce the overall size, mass and cost of a new vehicle system.

Cryogenic on-orbit liquid depot storage acquisition and transfer (COLD-SAT) experiment subsystem instrumentation and wire harness design report

NASA Technical Reports Server (NTRS)

Edwards, Lawrence G.

1994-01-01

Subcritical cryogens such as liquid hydrogen (LH2) and liquid oxygen (LO2) are required for space based transportation propellant, reactant, and life support systems. Future long-duration space missions will require on-orbit systems capable of long-term cryogen storage and efficient fluid transfer capabilities. COLD-SAT, which stands for cryogenic orbiting liquid depot-storage acquisition and transfer, is a free-flying liquid hydrogen management flight experiment. Experiments to determine optimum methods of fluid storage and transfer will be performed on the COLD-SAT mission. The success of the mission is directly related to the type and accuracy of measurements made. The instrumentation and measurement techniques used are therefore critical to the success of the mission. This paper presents the results of the COLD-SAT experiment subsystem instrumentation and wire harness design effort. Candidate transducers capable of fulfilling the COLD-SAT experiment measurement requirements are identified. Signal conditioning techniques, data acquisition requirements, and measurement uncertainty analysis are presented. Electrical harnessing materials and wiring techniques for the instrumentation designed to minimize heat conduction to the cryogenic tanks and provide optimum measurement accuracy are listed.

Scanning thin-sheet laser imaging microscopy (sTSLIM) with structured illumination and HiLo background rejection.

PubMed Central

Schröter, Tobias J.; Johnson, Shane B.; John, Kerstin; Santi, Peter A.

2011-01-01

We report replacement of one side of a static illumination, dual sided, thin-sheet laser imaging microscope (TSLIM) with an intensity modulated laser scanner in order to implement structured illumination (SI) and HiLo image demodulation techniques for background rejection. The new system is equipped with one static and one scanned light-sheet and is called a scanning thin-sheet laser imaging microscope (sTSLIM). It is an optimized version of a light-sheet fluorescent microscope that is designed to image large specimens (<15 mm in diameter). In this paper we describe the hardware and software modifications to TSLIM that allow for static and uniform light-sheet illumination with SI and HiLo image demodulation. The static light-sheet has a thickness of 3.2 µm; whereas, the scanned side has a light-sheet thickness of 4.2 µm. The scanned side images specimens with subcellular resolution (<1 µm lateral and <4 µm axial resolution) with a size up to 15 mm. SI and HiLo produce superior contrast compared to both the uniform static and scanned light-sheets. HiLo contrast was greater than SI and is faster and more robust than SI because as it produces images in two-thirds of the time and exhibits fewer intensity streaking artifacts. PMID:22254177

Liquid Oxygen/Liquid Methane Ascent Main Engine Technology Development

NASA Technical Reports Server (NTRS)

Robinson, Joel W.; Stephenson, David D.

2008-01-01

The National Aeronautics & Space Administration (NASA) has identified Liquid Oxygen (LO2)/Liquid Methane (LCH4) as a potential propellant combination for future space vehicles based upon the Exploration Systems Architecture Study (ESAS). The technology is estimated to have higher performance and lower overall systems mass compared to existing hypergolic propulsion systems. The current application considering this technology is the lunar ascent main engine (AME). AME is anticipated to be an expendable, pressure-fed engine to provide ascent from the moon at the completion of a 210 day lunar stay. The engine is expected to produce 5,500 lbf (24,465 N) thrust with variable inlet temperatures due to the cryogenic nature of the fuel and oxidizer. The primary technology risks include establishing reliable and robust ignition in vacuum conditions, maximizing specific impulse, developing rapid start capability for the descent abort, providing the capability for two starts and producing a total engine bum time over 500 seconds. This paper will highlight the efforts of the Marshall Space Flight Center (MSFC) in addressing risk reduction activities for this technology.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Anastasiou, Charalampos; Duhr, Claude; Dulat, Falko

We present the cross-section for the threshold production of the Higgs boson at hadron-colliders at next-to-next-to-next-to-leading order (N 3LO) in perturbative QCD. Furthermore, we present an analytic expression for the partonic cross-section at threshold and the impact of these corrections on the numerical estimates for the hadronic cross-section at the LHC. With this result we achieve a major milestone towards a complete evaluation of the cross-section at N 3LO which will reduce the theoretical uncertainty in the determination of the strengths of the Higgs boson interactions.

Robust Exploration and Commercial Missions to the Moon Using LANTR Propulsion and Lunar Liquid Oxygen Derived from FeO-Rich Pyroclastic Deposits

NASA Technical Reports Server (NTRS)

Borowski, Stanley K.; Ryan, Stephen W.; Burke, Laura M.; McCurdy, David R.; Fittje, James E.; Joyner, Claude R.

2017-01-01

Studies conducted by NASA and its contractors (early 1980s early 1990s) indicated a substantial benefit from using lunar-derived propellants specifically lunar-derived LO2 (LLO2) or LUNOX in a lunar space transportation system (LTS). With a LTS using LO2/LH2 chemical rockets, approx. 6 kilograms (kg) of mass in low Earth orbit (LEO) is required to place 1 kg of payload on the lunar surface (LS). Of this 6 kg, approx. 70% (4.2 kg) is propellant and 6/7th of this mass (3.6 kg) is oxygen assuming an O/H MR 6:1. Since the cost of placing a kilogram of mass on the LS is approx. 6X the cost of delivering it to LEO, the ability to produce and utilize LUNOX or lunar-derived LO2 and hydrogen (LLH2) from lunar polar ice (LPI) deposits can provide significant mission leverage. Providing LUNOX for use in fuel cells, life support systems and LO2/LH2 chemical rockets used on lunar landing vehicles (LLVs), can allow high value cargo (people, manufacturing and scientific equipment, etc.) to be transported to LEO, then to the Moon instead of bulk LO2 propellant. Oxygen is abundant in the lunar regolith (approx. 43% by mass) and can be extracted using a variety of techniques, such as hydrogen reduction of ilmenite (FeOTiO2) or FeO-rich volcanic glass (orange soil) discovered during the Apollo 17 mission to Taurus-Littrow. While considerable interest has been expressed about mining and processing LPI for rocket propellant, ground truth must first be established to quantify the physical state of the ice (e.g., its vertical thickness and areal extent, levels of soil contamination, etc.) and the deep, extremely cold (approx. 26-100 K) permanently shadowed craters where the ice resides.

A local framework for calculating coupled cluster singles and doubles excitation energies (LoFEx-CCSD)

DOE PAGES

Baudin, Pablo; Bykov, Dmytro; Liakh, Dmitry I.; ...

2017-02-22

Here, the recently developed Local Framework for calculating Excitation energies (LoFEx) is extended to the coupled cluster singles and doubles (CCSD) model. In the new scheme, a standard CCSD excitation energy calculation is carried out within a reduced excitation orbital space (XOS), which is composed of localised molecular orbitals and natural transition orbitals determined from time-dependent Hartree–Fock theory. The presented algorithm uses a series of reduced second-order approximate coupled cluster singles and doubles (CC2) calculations to optimise the XOS in a black-box manner. This ensures that the requested CCSD excitation energies have been determined to a predefined accuracy compared tomore » a conventional CCSD calculation. We present numerical LoFEx-CCSD results for a set of medium-sized organic molecules, which illustrate the black-box nature of the approach and the computational savings obtained for transitions that are local compared to the size of the molecule. In fact, for such local transitions, the LoFEx-CCSD scheme can be applied to molecular systems where a conventional CCSD implementation is intractable.« less

A Lewis acid β-diiminato-zinc-complex as all-rounder for co- and terpolymerisation of various epoxides with carbon dioxide.

PubMed

Reiter, M; Vagin, S; Kronast, A; Jandl, C; Rieger, B

2017-03-01

A β-diiminato-zinc-N(SiMe 3 ) 2 complex ( 1 ) was synthesised and fully characterised, including an X-ray diffraction study. The activity of catalyst 1 towards the coupling reaction of CO 2 and various epoxides, including propylene oxide (PO), cyclohexene oxide (CHO), styrene oxide (SO), limonene oxide (LO), octene oxide (OO) and epichlorohydrin (ECH), was investigated. Terpolymerisation of CO 2 , PO and LO, as well as CO 2 , CHO and PO, was successfully realised, resulting in polymers with adjustable glass transition temperatures and transparencies. Reaction conditions such as temperature, pressure and catalyst concentration were varied to find the optimal reaction values, especially regarding LO/CO 2 . In situ IR experiments hinted that at 60 °C and a critical LO concentration, polymerisation and depolymerisation are in an equilibrium (ceiling effect). Pressurising catalyst 1 with carbon dioxide resulted in a dimeric catalyst ( 2 ) with a OSiMe 3 group as a new initiator. Homopolymerisation of different epoxides was carried out in order to explain the reactivity concerning copolymerisation reaction of CO 2 and epoxides.

Robust Exploration and Commercial Missions to the Moon Using Nuclear Thermal Rocket Propulsion and Lunar Liquid Oxygen Derived from FeO-Rich Pyroclasitc Deposits

NASA Technical Reports Server (NTRS)

Borowski, Stanley K.; Ryan, Stephen W.; Burke, Laura M.; McCurdy, David R.; Fittje, James E.; Joyner, Claude R.

2018-01-01

The nuclear thermal rocket (NTR) has frequently been identified as a key space asset required for the human exploration of Mars. This proven technology can also provide the affordable access through cislunar space necessary for commercial development and sustained human presence on the Moon. It is a demonstrated technology capable of generating both high thrust and high specific impulse (I(sub sp) approx. 900 s) twice that of today's best chemical rockets. Nuclear lunar transfer vehicles-consisting of a propulsion stage using three approx. 16.5-klb(sub f) small nuclear rocket engines (SNREs), an in-line propellant tank, plus the payload-are reusable, enabling a variety of lunar missions. These include cargo delivery and crewed lunar landing missions. Even weeklong ''tourism'' missions carrying passengers into lunar orbit for a day of sightseeing and picture taking are possible. The NTR can play an important role in the next phase of lunar exploration and development by providing a robust in-space lunar transportation system (LTS) that can allow initial outposts to evolve into settlements supported by a variety of commercial activities such as in-situ propellant production used to supply strategically located propellant depots and transportation nodes. The use of lunar liquid oxygen (LLO2) derived from iron oxide (FeO)-rich volcanic glass beads, found in numerous pyroclastic deposits on the Moon, can significantly reduce the launch mass requirements from Earth by enabling reusable, surface-based lunar landing vehicles (LLVs)that use liquid oxygen and hydrogen (LO2/LH2) chemical rocket engines. Afterwards, a LO2/LH2 propellant depot can be established in lunar equatorial orbit to supply the LTS. At this point a modified version of the conventional NTR-called the LO2-augmented NTR, or LANTR-is introduced into the LTS allowing bipropellant operation and leveraging the mission benefits of refueling with lunar-derived propellants for Earth return. The bipropellant LANTR engine utilizes the large divergent section of its nozzle as an ''afterburner'' into which oxygen is injected and supersonically combusted with nuclear preheated hydrogen emerging from the engine's choked sonic throat-essentially ''scramjet propulsion in reverse.'' By varying the oxygen-to-hydrogen mixture ratio, LANTR engines can operate over a range of thrust and I(sub sp) values while the reactor core power level remains relatively constant. A LANTR-based LTS offers unique mission capabilities including short-transit-time crewed cargo transports. Even a ''commuter'' shuttle service may be possible allowing ''one-way'' trip times to and from the Moon on the order of 36 hours or less. If only 1% of the extracted LLO2 propellant from identified resource sites were available for use in lunar orbit, such a supply could support daily commuter flights to the Moon for many thousands of years! This report outlines an evolutionary architecture and examines a variety of mission types and transfer vehicle designs, along with the increasing demands on LLO2 production as mission complexity and velocity change delta V requirements increase. A comparison of vehicle features and engine operating characteristics, for both NTR and LANTR engines, is also provided along with a discussion of the propellant production and mining requirements associated with using FeO-rich volcanic glass as source material.

Structural design of liquid oxygen/liquid methane robotic lander JANUS

NASA Astrophysics Data System (ADS)

Chaidez, Mariana

As the attempt to send humans to Mars has gained momentum in the last decade, the need to find alternative propellants that are safer, less toxic, and yields a better performance has become apparent [1]. Liquid methane and oxygen have emerged as a suitable alternative. In addition, the incorporation of liquid methane/liquid oxygen into the propulsion system has demonstrated an increase in engine performance, as well as a reduction in the volume, size and complexity of the propulsion system. In an attempt to further understand the technologies that are possible to develop using liquid oxygen (LO 2) and liquid methane (LCH4), a preliminary design of a robotic lander JANUS is being completed by the Center for Space Exploration and Technology Research (cSTER). The structural design of the vehicle is important because it acts as the skeleton of the vehicle and dictates the maneuverability of the robotic lander. To develop the structure of the robotic lander, six different design vehicle concepts with varying tank configurations were considered. Finite Element Analysis (FEA) was completed on each model to optimize each vehicle. Trade studies were completed to choose the best design for JANUS. Upon completion of the trade studies the design for the first prototype of JANUS was initiated in which the tank and thrust modules were designed. This thesis will describe the design process for the structural design of the JANUS.

Developing Higher-Order Thinking Skills through WebQuests

ERIC Educational Resources Information Center

Polly, Drew; Ausband, Leigh

2009-01-01

In this study, 32 teachers participated in a year-long professional development project related to technology integration in which they designed and implemented a WebQuest. This paper describes the extent to which higher-order thinking skills (HOTS) and levels of technology implementation (LoTI) occur in the WebQuests that participants designed.…

Study of liquid and vapor flow into a Centaur capillary device

NASA Technical Reports Server (NTRS)

Blatt, M. H.; Risberg, J. A.

1979-01-01

The following areas of liquid and vapor flow were analyzed and experimentally evaluated; 1) the refilling of capillary devices with settled liquid, and 2) vapor flow across wetted screens. These investigations resulted in: 1) the development of a versatile computer program that was successfully correlated with test data and used to predict Centaur D-1S LO2 and LH2 start basket refilling; 2) the development of a semi-empirical model that was only partially correlated with data due to difficulties in obtaining repeatable test results. Also, a comparison was made to determine the best propellant management system for the Centaur D-1S vehicle. The comparison identified the basline Centaur D-1S system (using pressurization, boost pumps and propellant settling) as the best candidate based on payload weight penalty. However, other comparison criteria and advanced mission condition were identified where pressure fed systems, thermally subcooled boost pumps and capillary devices would be selected as attractive alternatives.

77 FR 10579 - Self-Regulatory Organizations; International Securities Exchange, LLC; Notice of Filing and...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-02-22

... participants that add or remove liquidity in the Complex Order Book (``maker/taker fees'') in symbols that are... liquidity on the Complex Order Book and $0.30 per contract ($0.32 per contract in the Select Symbols) for taking liquidity from the Complex Order Book. ISE market makers who take liquidity from the Complex Order...

Structural ordering at solid-liquid interfaces in Al-Sm system: A molecular-dynamics study

DOE PAGES

Sun, Yang; Zhang, Feng; Ye, Zhuo; ...

2016-07-12

The structural ordering at solid-liquid interfaces far from equilibrium is studied with molecular dynamics simulations for the Al-Sm system. Using the van-Hove self-correlation function as the criterion to identify attachment/detachment events that occur at the interface, we are able to determine the time-dependent interface position, and characterize the detailed interfacial structure ordering surrounding the attached atoms. For the interface between an undercooled Al90Sm10 liquid and a metastable cubic structure, the solid induces the crystalline order of the cubic phase in the liquid layers, promoting the continuous growth of the crystal phase. When the same liquid is put in contact withmore » f.c.c. Al, Sm from the liquid can still attach to the solid interface despite its insolubility in the Al lattice. Non-f.c.c. order is revealed surrounding the attached Sm atoms. Lastly, we show that the local structure ordering at interface is highly correlated to solid packing and liquid ordering.« less

Scanning thin-sheet laser imaging microscopy (sTSLIM) with structured illumination and HiLo background rejection.

PubMed

Schröter, Tobias J; Johnson, Shane B; John, Kerstin; Santi, Peter A

2012-01-01

We report replacement of one side of a static illumination, dual sided, thin-sheet laser imaging microscope (TSLIM) with an intensity modulated laser scanner in order to implement structured illumination (SI) and HiLo image demodulation techniques for background rejection. The new system is equipped with one static and one scanned light-sheet and is called a scanning thin-sheet laser imaging microscope (sTSLIM). It is an optimized version of a light-sheet fluorescent microscope that is designed to image large specimens (<15 mm in diameter). In this paper we describe the hardware and software modifications to TSLIM that allow for static and uniform light-sheet illumination with SI and HiLo image demodulation. The static light-sheet has a thickness of 3.2 µm; whereas, the scanned side has a light-sheet thickness of 4.2 µm. The scanned side images specimens with subcellular resolution (<1 µm lateral and <4 µm axial resolution) with a size up to 15 mm. SI and HiLo produce superior contrast compared to both the uniform static and scanned light-sheets. HiLo contrast was greater than SI and is faster and more robust than SI because as it produces images in two-thirds of the time and exhibits fewer intensity streaking artifacts. 2011 Optical Society of America

Measurement of the differential cross sections for the associated production of a W boson and jets in proton-proton collisions at s = 13 TeV

DOE PAGES

Sirunyan, A. M.; Tumasyan, A.; Adam, W.; ...

2017-10-27

Here, a measurement of the differential cross sections for a W boson produced in association with jets in the muon decay channel is presented. The measurement is based on 13 TeV proton-proton collision data corresponding to an integrated luminosity of 2.2 fb –1, recorded by the CMS detector at the LHC. The cross sections are reported as functions of jet multiplicity, jet transverse momentum p T, jet rapidity, the scalar p T sum of the jets, and angular correlations between the muon and the jet for different jet multiplicities. The measured cross sections are in agreement with predictions that includemore » multileg leading-order (LO) and next-to-LO matrix element calculations interfaced with parton showers, as well as a next-to-next-to-LO calculation for the W boson and one jet production.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vesely, P.; Michel, N.; Toivanen, J.

For over four decades, the Skyrme functional within various parametrizations has been used to calculate nuclear properties. In the last few years there was a number of attempts to improve its performance and introduce generalized forms. In particular, the most general phenomenological quasi-local energy density functional, which contains all combinations of density, spin-density, and their derivatives up to the sixth order (N{sup 3}LO), was proposed in reference [1]. Since in the phenomenological functional approaches the particle-particle (pp) interaction channel is treated independently from the particle-hole (ph) channel, there remains a question of what pairing interaction is suitable to use withinmore » the N{sup 3}LO energy functional. In our study, we use the separable, finite-range, translationally invariant form given in [2], which we generalize to the arbitrary angular momentum channel. We discuss the application of this pairing interaction within the N{sup 3}LO energy functional.« less

Measurement of the differential cross sections for the associated production of a W boson and jets in proton-proton collisions at s = 13 TeV

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sirunyan, A. M.; Tumasyan, A.; Adam, W.

Here, a measurement of the differential cross sections for a W boson produced in association with jets in the muon decay channel is presented. The measurement is based on 13 TeV proton-proton collision data corresponding to an integrated luminosity of 2.2 fb –1, recorded by the CMS detector at the LHC. The cross sections are reported as functions of jet multiplicity, jet transverse momentum p T, jet rapidity, the scalar p T sum of the jets, and angular correlations between the muon and the jet for different jet multiplicities. The measured cross sections are in agreement with predictions that includemore » multileg leading-order (LO) and next-to-LO matrix element calculations interfaced with parton showers, as well as a next-to-next-to-LO calculation for the W boson and one jet production.« less

Measurement of the differential cross sections for the associated production of a W boson and jets in proton-proton collisions at √{s }=13 TeV

NASA Astrophysics Data System (ADS)

Sirunyan, A. M.; Tumasyan, A.; Adam, W.; Ambrogi, F.; Asilar, E.; Bergauer, T.; Brandstetter, J.; Brondolin, E.; Dragicevic, M.; Erö, J.; Flechl, M.; Friedl, M.; Frühwirth, R.; Ghete, V. M.; Grossmann, J.; Hrubec, J.; Jeitler, M.; König, A.; Krammer, N.; Krätschmer, I.; Liko, D.; Madlener, T.; Mikulec, I.; Pree, E.; Rabady, D.; Rad, N.; Rohringer, H.; Schieck, J.; Schöfbeck, R.; Spanring, M.; Spitzbart, D.; Strauss, J.; Waltenberger, W.; Wittmann, J.; Wulz, C.-E.; Zarucki, M.; Chekhovsky, V.; Mossolov, V.; Suarez Gonzalez, J.; De Wolf, E. A.; Di Croce, D.; Janssen, X.; Lauwers, J.; Van De Klundert, M.; Van Haevermaet, H.; Van Mechelen, P.; Van Remortel, N.; Abu Zeid, S.; Blekman, F.; D'Hondt, J.; De Bruyn, I.; De Clercq, J.; Deroover, K.; Flouris, G.; Lontkovskyi, D.; Lowette, S.; Moortgat, S.; Moreels, L.; Olbrechts, A.; Python, Q.; Skovpen, K.; Tavernier, S.; Van Doninck, W.; Van Mulders, P.; Van Parijs, I.; Brun, H.; Clerbaux, B.; De Lentdecker, G.; Delannoy, H.; Fasanella, G.; Favart, L.; Goldouzian, R.; Grebenyuk, A.; Karapostoli, G.; Lenzi, T.; Luetic, J.; Maerschalk, T.; Marinov, A.; Randle-conde, A.; Seva, T.; Vander Velde, C.; Vanlaer, P.; Vannerom, D.; Yonamine, R.; Zenoni, F.; Zhang, F.; Cimmino, A.; Cornelis, T.; Dobur, D.; Fagot, A.; Gul, M.; Khvastunov, I.; Poyraz, D.; Roskas, C.; Salva, S.; Tytgat, M.; Verbeke, W.; Zaganidis, N.; Bakhshiansohi, H.; Bondu, O.; Brochet, S.; Bruno, G.; Caudron, A.; De Visscher, S.; Delaere, C.; Delcourt, M.; Francois, B.; Giammanco, A.; Jafari, A.; Komm, M.; Krintiras, G.; Lemaitre, V.; Magitteri, A.; Mertens, A.; Musich, M.; Piotrzkowski, K.; Quertenmont, L.; Vidal Marono, M.; Wertz, S.; Beliy, N.; Aldá Júnior, W. L.; Alves, F. L.; Alves, G. A.; Brito, L.; Correa Martins Junior, M.; Hensel, C.; Moraes, A.; Pol, M. E.; Rebello Teles, P.; Belchior Batista Das Chagas, E.; Carvalho, W.; Chinellato, J.; Custódio, A.; Da Costa, E. M.; Da Silveira, G. G.; De Jesus Damiao, D.; Fonseca De Souza, S.; Huertas Guativa, L. M.; Malbouisson, H.; Melo De Almeida, M.; Mora Herrera, C.; Mundim, L.; Nogima, H.; Santoro, A.; Sznajder, A.; Tonelli Manganote, E. J.; Torres Da Silva De Araujo, F.; Vilela Pereira, A.; Ahuja, S.; Bernardes, C. A.; Fernandez Perez Tomei, T. R.; Gregores, E. M.; Mercadante, P. G.; Novaes, S. F.; Padula, Sandra S.; Romero Abad, D.; Ruiz Vargas, J. C.; Aleksandrov, A.; Hadjiiska, R.; Iaydjiev, P.; Misheva, M.; Rodozov, M.; Shopova, M.; Stoykova, S.; Sultanov, G.; Dimitrov, A.; Glushkov, I.; Litov, L.; Pavlov, B.; Petkov, P.; Fang, W.; Gao, X.; Ahmad, M.; Bian, J. G.; Chen, G. M.; Chen, H. S.; Chen, M.; Chen, Y.; Jiang, C. H.; Leggat, D.; Liu, Z.; Romeo, F.; Shaheen, S. M.; Spiezia, A.; Tao, J.; Wang, C.; Wang, Z.; Yazgan, E.; Zhang, H.; Zhao, J.; Ban, Y.; Chen, G.; Li, Q.; Liu, S.; Mao, Y.; Qian, S. J.; Wang, D.; Xu, Z.; Avila, C.; Cabrera, A.; Chaparro Sierra, L. F.; Florez, C.; González Hernández, C. F.; Ruiz Alvarez, J. D.; Courbon, B.; Godinovic, N.; Lelas, D.; Puljak, I.; Ribeiro Cipriano, P. M.; Sculac, T.; Antunovic, Z.; Kovac, M.; Brigljevic, V.; Ferencek, D.; Kadija, K.; Mesic, B.; Susa, T.; Ather, M. W.; Attikis, A.; Mavromanolakis, G.; Mousa, J.; Nicolaou, C.; Ptochos, F.; Razis, P. A.; Rykaczewski, H.; Finger, M.; Finger, M.; Carrera Jarrin, E.; Assran, Y.; Mahmoud, M. A.; Mahrous, A.; Dewanjee, R. K.; Kadastik, M.; Perrini, L.; Raidal, M.; Tiko, A.; Veelken, C.; Eerola, P.; Pekkanen, J.; Voutilainen, M.; Härkönen, J.; Järvinen, T.; Karimäki, V.; Kinnunen, R.; Lampén, T.; Lassila-Perini, K.; Lehti, S.; Lindén, T.; Luukka, P.; Tuominen, E.; Tuominiemi, J.; Tuovinen, E.; Talvitie, J.; Tuuva, T.; Besancon, M.; Couderc, F.; Dejardin, M.; Denegri, D.; Faure, J. L.; Ferri, F.; Ganjour, S.; Ghosh, S.; Givernaud, A.; Gras, P.; Hamel de Monchenault, G.; Jarry, P.; Kucher, I.; Locci, E.; Machet, M.; Malcles, J.; Negro, G.; Rander, J.; Rosowsky, A.; Sahin, M. Ö.; Titov, M.; Abdulsalam, A.; Antropov, I.; Baffioni, S.; Beaudette, F.; Busson, P.; Cadamuro, L.; Charlot, C.; Granier de Cassagnac, R.; Jo, M.; Lisniak, S.; Lobanov, A.; Martin Blanco, J.; Nguyen, M.; Ochando, C.; Ortona, G.; Paganini, P.; Pigard, P.; Regnard, S.; Salerno, R.; Sauvan, J. B.; Sirois, Y.; Stahl Leiton, A. G.; Strebler, T.; Yilmaz, Y.; Zabi, A.; Zghiche, A.; Agram, J.-L.; Andrea, J.; Bloch, D.; Brom, J.-M.; Buttignol, M.; Chabert, E. C.; Chanon, N.; Collard, C.; Conte, E.; Coubez, X.; Fontaine, J.-C.; Gelé, D.; Goerlach, U.; Jansová, M.; Le Bihan, A.-C.; Tonon, N.; Van Hove, P.; Gadrat, S.; Beauceron, S.; Bernet, C.; Boudoul, G.; Chierici, R.; Contardo, D.; Depasse, P.; El Mamouni, H.; Fay, J.; Finco, L.; Gascon, S.; Gouzevitch, M.; Grenier, G.; Ille, B.; Lagarde, F.; Laktineh, I. B.; Lethuillier, M.; Mirabito, L.; Pequegnot, A. L.; Perries, S.; Popov, A.; Sordini, V.; Vander Donckt, M.; Viret, S.; Khvedelidze, A.; Tsamalaidze, Z.; Autermann, C.; Beranek, S.; Feld, L.; Kiesel, M. K.; Klein, K.; Lipinski, M.; Preuten, M.; Schomakers, C.; Schulz, J.; Verlage, T.; Albert, A.; Brodski, M.; Dietz-Laursonn, E.; Duchardt, D.; Endres, M.; Erdmann, M.; Erdweg, S.; Esch, T.; Fischer, R.; Güth, A.; Hamer, M.; Hebbeker, T.; Heidemann, C.; Hoepfner, K.; Knutzen, S.; Merschmeyer, M.; Meyer, A.; Millet, P.; Mukherjee, S.; Olschewski, M.; Padeken, K.; Pook, T.; Radziej, M.; Reithler, H.; Rieger, M.; Scheuch, F.; Teyssier, D.; Thüer, S.; Flügge, G.; Kargoll, B.; Kress, T.; Künsken, A.; Lingemann, J.; Müller, T.; Nehrkorn, A.; Nowack, A.; Pistone, C.; Pooth, O.; Stahl, A.; Aldaya Martin, M.; Arndt, T.; Asawatangtrakuldee, C.; Beernaert, K.; Behnke, O.; Behrens, U.; Bin Anuar, A. A.; Borras, K.; Botta, V.; Campbell, A.; Connor, P.; Contreras-Campana, C.; Costanza, F.; Diez Pardos, C.; Eckerlin, G.; Eckstein, D.; Eichhorn, T.; Eren, E.; Gallo, E.; Garay Garcia, J.; Geiser, A.; Gizhko, A.; Grados Luyando, J. M.; Grohsjean, A.; Gunnellini, P.; Harb, A.; Hauk, J.; Hempel, M.; Jung, H.; Kalogeropoulos, A.; Kasemann, M.; Keaveney, J.; Kleinwort, C.; Korol, I.; Krücker, D.; Lange, W.; Lelek, A.; Lenz, T.; Leonard, J.; Lipka, K.; Lohmann, W.; Mankel, R.; Melzer-Pellmann, I.-A.; Meyer, A. B.; Mittag, G.; Mnich, J.; Mussgiller, A.; Ntomari, E.; Pitzl, D.; Placakyte, R.; Raspereza, A.; Roland, B.; Savitskyi, M.; Saxena, P.; Shevchenko, R.; Spannagel, S.; Stefaniuk, N.; Van Onsem, G. P.; Walsh, R.; Wen, Y.; Wichmann, K.; Wissing, C.; Zenaiev, O.; Bein, S.; Blobel, V.; Centis Vignali, M.; Draeger, A. R.; Dreyer, T.; Garutti, E.; Gonzalez, D.; Haller, J.; Hinzmann, A.; Hoffmann, M.; Karavdina, A.; Klanner, R.; Kogler, R.; Kovalchuk, N.; Kurz, S.; Lapsien, T.; Marchesini, I.; Marconi, D.; Meyer, M.; Niedziela, M.; Nowatschin, D.; Pantaleo, F.; Peiffer, T.; Perieanu, A.; Scharf, C.; Schleper, P.; Schmidt, A.; Schumann, S.; Schwandt, J.; Sonneveld, J.; Stadie, H.; Steinbrück, G.; Stober, F. M.; Stöver, M.; Tholen, H.; Troendle, D.; Usai, E.; Vanelderen, L.; Vanhoefer, A.; Vormwald, B.; Akbiyik, M.; Barth, C.; Baur, S.; Butz, E.; Caspart, R.; Chwalek, T.; Colombo, F.; De Boer, W.; Dierlamm, A.; Freund, B.; Friese, R.; Giffels, M.; Gilbert, A.; Haitz, D.; Hartmann, F.; Heindl, S. M.; Husemann, U.; Kassel, F.; Kudella, S.; Mildner, H.; Mozer, M. U.; Müller, Th.; Plagge, M.; Quast, G.; Rabbertz, K.; Schröder, M.; Shvetsov, I.; Sieber, G.; Simonis, H. J.; Ulrich, R.; Wayand, S.; Weber, M.; Weiler, T.; Williamson, S.; Wöhrmann, C.; Wolf, R.; Anagnostou, G.; Daskalakis, G.; Geralis, T.; Giakoumopoulou, V. A.; Kyriakis, A.; Loukas, D.; Topsis-Giotis, I.; Kesisoglou, S.; Panagiotou, A.; Saoulidou, N.; Evangelou, I.; Foudas, C.; Kokkas, P.; Manthos, N.; Papadopoulos, I.; Paradas, E.; Strologas, J.; Triantis, F. A.; Csanad, M.; Filipovic, N.; Pasztor, G.; Bencze, G.; Hajdu, C.; Horvath, D.; Hunyadi, Á.; Sikler, F.; Veszpremi, V.; Vesztergombi, G.; Zsigmond, A. J.; Beni, N.; Czellar, S.; Karancsi, J.; Makovec, A.; Molnar, J.; Szillasi, Z.; Bartók, M.; Raics, P.; Trocsanyi, Z. L.; Ujvari, B.; Choudhury, S.; Komaragiri, J. R.; Bahinipati, S.; Bhowmik, S.; Mal, P.; Mandal, K.; Nayak, A.; Sahoo, D. K.; Sahoo, N.; Swain, S. K.; Bansal, S.; Beri, S. B.; Bhatnagar, V.; Bhawandeep, U.; Chawla, R.; Dhingra, N.; Kalsi, A. K.; Kaur, A.; Kaur, M.; Kumar, R.; Kumari, P.; Mehta, A.; Singh, J. B.; Walia, G.; Kumar, Ashok; Shah, Aashaq; Bhardwaj, A.; Chauhan, S.; Choudhary, B. C.; Garg, R. B.; Keshri, S.; Kumar, A.; Malhotra, S.; Naimuddin, M.; Ranjan, K.; Sharma, R.; Sharma, V.; Bhardwaj, R.; Bhattacharya, R.; Bhattacharya, S.; Dey, S.; Dutt, S.; Dutta, S.; Ghosh, S.; Majumdar, N.; Modak, A.; Mondal, K.; Mukhopadhyay, S.; Nandan, S.; Purohit, A.; Roy, A.; Roy, D.; Roy Chowdhury, S.; Sarkar, S.; Sharan, M.; Thakur, S.; Behera, P. K.; Chudasama, R.; Dutta, D.; Jha, V.; Kumar, V.; Mohanty, A. K.; Netrakanti, P. K.; Pant, L. M.; Shukla, P.; Topkar, A.; Aziz, T.; Dugad, S.; Mahakud, B.; Mitra, S.; Mohanty, G. B.; Parida, B.; Sur, N.; Sutar, B.; Banerjee, S.; Bhattacharya, S.; Chatterjee, S.; Das, P.; Guchait, M.; Jain, Sa.; Kumar, S.; Maity, M.; Majumder, G.; Mazumdar, K.; Sarkar, T.; Wickramage, N.; Chauhan, S.; Dube, S.; Hegde, V.; Kapoor, A.; Kothekar, K.; Pandey, S.; Rane, A.; Sharma, S.; Chenarani, S.; Eskandari Tadavani, E.; Etesami, S. M.; Khakzad, M.; Mohammadi Najafabadi, M.; Naseri, M.; Paktinat Mehdiabadi, S.; Rezaei Hosseinabadi, F.; Safarzadeh, B.; Zeinali, M.; Felcini, M.; Grunewald, M.; Abbrescia, M.; Calabria, C.; Caputo, C.; Colaleo, A.; Creanza, D.; Cristella, L.; De Filippis, N.; De Palma, M.; Errico, F.; Fiore, L.; Iaselli, G.; Lezki, S.; Maggi, G.; Maggi, M.; Miniello, G.; My, S.; Nuzzo, S.; Pompili, A.; Pugliese, G.; Radogna, R.; Ranieri, A.; Selvaggi, G.; Sharma, A.; Silvestris, L.; Venditti, R.; Verwilligen, P.; Abbiendi, G.; Battilana, C.; Bonacorsi, D.; Braibant-Giacomelli, S.; Brigliadori, L.; Campanini, R.; Capiluppi, P.; Castro, A.; Cavallo, F. R.; Chhibra, S. S.; Codispoti, G.; Cuffiani, M.; Dallavalle, G. M.; Fabbri, F.; Fanfani, A.; Fasanella, D.; Giacomelli, P.; Guiducci, L.; Marcellini, S.; Masetti, G.; Navarria, F. L.; Perrotta, A.; Rossi, A. M.; Rovelli, T.; Siroli, G. P.; Tosi, N.; Albergo, S.; Costa, S.; Di Mattia, A.; Giordano, F.; Potenza, R.; Tricomi, A.; Tuve, C.; Barbagli, G.; Chatterjee, K.; Ciulli, V.; Civinini, C.; D'Alessandro, R.; Focardi, E.; Lenzi, P.; Meschini, M.; Paoletti, S.; Russo, L.; Sguazzoni, G.; Strom, D.; Viliani, L.; Benussi, L.; Bianco, S.; Fabbri, F.; Piccolo, D.; Primavera, F.; Calvelli, V.; Ferro, F.; Robutti, E.; Tosi, S.; Brianza, L.; Brivio, F.; Ciriolo, V.; Dinardo, M. E.; Fiorendi, S.; Gennai, S.; Ghezzi, A.; Govoni, P.; Malberti, M.; Malvezzi, S.; Manzoni, R. A.; Menasce, D.; Moroni, L.; Paganoni, M.; Pauwels, K.; Pedrini, D.; Pigazzini, S.; Ragazzi, S.; Tabarelli de Fatis, T.; Buontempo, S.; Cavallo, N.; Di Guida, S.; Fabozzi, F.; Fienga, F.; Iorio, A. O. M.; Khan, W. A.; Lista, L.; Meola, S.; Paolucci, P.; Sciacca, C.; Thyssen, F.; Azzi, P.; Bacchetta, N.; Benato, L.; Bisello, D.; Boletti, A.; Checchia, P.; Dall'Osso, M.; De Castro Manzano, P.; Dorigo, T.; Dosselli, U.; Gasparini, F.; Gasparini, U.; Gonella, F.; Gulmini, M.; Lacaprara, S.; Margoni, M.; Meneguzzo, A. T.; Pozzobon, N.; Ronchese, P.; Rossin, R.; Simonetto, F.; Torassa, E.; Ventura, S.; Zanetti, M.; Zotto, P.; Zumerle, G.; Braghieri, A.; Fallavollita, F.; Magnani, A.; Montagna, P.; Ratti, S. P.; Re, V.; Ressegotti, M.; Riccardi, C.; Salvini, P.; Vai, I.; Vitulo, P.; Alunni Solestizi, L.; Biasini, M.; Bilei, G. M.; Cecchi, C.; Ciangottini, D.; Fanò, L.; Lariccia, P.; Leonardi, R.; Manoni, E.; Mantovani, G.; Mariani, V.; Menichelli, M.; Rossi, A.; Saha, A.; Santocchia, A.; Spiga, D.; Androsov, K.; Azzurri, P.; Bagliesi, G.; Bernardini, J.; Boccali, T.; Borrello, L.; Castaldi, R.; Ciocci, M. A.; Dell'Orso, R.; Fedi, G.; Giannini, L.; Giassi, A.; Grippo, M. T.; Ligabue, F.; Lomtadze, T.; Manca, E.; Mandorli, G.; Martini, L.; Messineo, A.; Palla, F.; Rizzi, A.; Savoy-Navarro, A.; Spagnolo, P.; Tenchini, R.; Tonelli, G.; Venturi, A.; Verdini, P. G.; Barone, L.; Cavallari, F.; Cipriani, M.; Del Re, D.; Diemoz, M.; Gelli, S.; Longo, E.; Margaroli, F.; Marzocchi, B.; Meridiani, P.; Organtini, G.; Paramatti, R.; Preiato, F.; Rahatlou, S.; Rovelli, C.; Santanastasio, F.; Amapane, N.; Arcidiacono, R.; Argiro, S.; Arneodo, M.; Bartosik, N.; Bellan, R.; Biino, C.; Cartiglia, N.; Cenna, F.; Costa, M.; Covarelli, R.; Degano, A.; Demaria, N.; Kiani, B.; Mariotti, C.; Maselli, S.; Migliore, E.; Monaco, V.; Monteil, E.; Monteno, M.; Obertino, M. M.; Pacher, L.; Pastrone, N.; Pelliccioni, M.; Pinna Angioni, G. L.; Ravera, F.; Romero, A.; Ruspa, M.; Sacchi, R.; Shchelina, K.; Sola, V.; Solano, A.; Staiano, A.; Traczyk, P.; Belforte, S.; Casarsa, M.; Cossutti, F.; Della Ricca, G.; Zanetti, A.; Kim, D. H.; Kim, G. N.; Kim, M. S.; Lee, J.; Lee, S.; Lee, S. 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J.; Kellams, N.; Lannon, K.; Loukas, N.; Marinelli, N.; Meng, F.; Mueller, C.; Musienko, Y.; Planer, M.; Reinsvold, A.; Ruchti, R.; Smith, G.; Taroni, S.; Wayne, M.; Wolf, M.; Woodard, A.; Alimena, J.; Antonelli, L.; Bylsma, B.; Durkin, L. S.; Flowers, S.; Francis, B.; Hart, A.; Hill, C.; Ji, W.; Liu, B.; Luo, W.; Puigh, D.; Winer, B. L.; Wulsin, H. W.; Benaglia, A.; Cooperstein, S.; Driga, O.; Elmer, P.; Hardenbrook, J.; Hebda, P.; Higginbotham, S.; Lange, D.; Luo, J.; Marlow, D.; Mei, K.; Ojalvo, I.; Olsen, J.; Palmer, C.; Piroué, P.; Stickland, D.; Tully, C.; Malik, S.; Norberg, S.; Barker, A.; Barnes, V. E.; Folgueras, S.; Gutay, L.; Jha, M. K.; Jones, M.; Jung, A. W.; Khatiwada, A.; Miller, D. H.; Neumeister, N.; Peng, C. C.; Schulte, J. F.; Sun, J.; Wang, F.; Xie, W.; Cheng, T.; Parashar, N.; Stupak, J.; Adair, A.; Akgun, B.; Chen, Z.; Ecklund, K. M.; Geurts, F. J. M.; Guilbaud, M.; Li, W.; Michlin, B.; Northup, M.; Padley, B. P.; Roberts, J.; Rorie, J.; Tu, Z.; Zabel, J.; Bodek, A.; de Barbaro, P.; Demina, R.; Duh, Y. t.; Ferbel, T.; Galanti, M.; Garcia-Bellido, A.; Han, J.; Hindrichs, O.; Khukhunaishvili, A.; Lo, K. H.; Tan, P.; Verzetti, M.; Ciesielski, R.; Goulianos, K.; Mesropian, C.; Agapitos, A.; Chou, J. P.; Gershtein, Y.; Gómez Espinosa, T. A.; Halkiadakis, E.; Heindl, M.; Hughes, E.; Kaplan, S.; Kunnawalkam Elayavalli, R.; Kyriacou, S.; Lath, A.; Montalvo, R.; Nash, K.; Osherson, M.; Saka, H.; Salur, S.; Schnetzer, S.; Sheffield, D.; Somalwar, S.; Stone, R.; Thomas, S.; Thomassen, P.; Walker, M.; Delannoy, A. G.; Foerster, M.; Heideman, J.; Riley, G.; Rose, K.; Spanier, S.; Thapa, K.; Bouhali, O.; Castaneda Hernandez, A.; Celik, A.; Dalchenko, M.; De Mattia, M.; Delgado, A.; Dildick, S.; Eusebi, R.; Gilmore, J.; Huang, T.; Kamon, T.; Mueller, R.; Pakhotin, Y.; Patel, R.; Perloff, A.; Perniè, L.; Rathjens, D.; Safonov, A.; Tatarinov, A.; Ulmer, K. A.; Akchurin, N.; Damgov, J.; De Guio, F.; Dudero, P. R.; Faulkner, J.; Gurpinar, E.; Kunori, S.; Lamichhane, K.; Lee, S. W.; Libeiro, T.; Peltola, T.; Undleeb, S.; Volobouev, I.; Wang, Z.; Greene, S.; Gurrola, A.; Janjam, R.; Johns, W.; Maguire, C.; Melo, A.; Ni, H.; Sheldon, P.; Tuo, S.; Velkovska, J.; Xu, Q.; Arenton, M. W.; Barria, P.; Cox, B.; Hirosky, R.; Ledovskoy, A.; Li, H.; Neu, C.; Sinthuprasith, T.; Sun, X.; Wang, Y.; Wolfe, E.; Xia, F.; Clarke, C.; Harr, R.; Karchin, P. E.; Sturdy, J.; Zaleski, S.; Buchanan, J.; Caillol, C.; Dasu, S.; Dodd, L.; Duric, S.; Gomber, B.; Grothe, M.; Herndon, M.; Hervé, A.; Hussain, U.; Klabbers, P.; Lanaro, A.; Levine, A.; Long, K.; Loveless, R.; Pierro, G. A.; Polese, G.; Ruggles, T.; Savin, A.; Smith, N.; Smith, W. H.; Taylor, D.; Woods, N.; CMS Collaboration

2017-10-01

A measurement of the differential cross sections for a W boson produced in association with jets in the muon decay channel is presented. The measurement is based on 13 TeV proton-proton collision data corresponding to an integrated luminosity of 2.2 fb-1 , recorded by the CMS detector at the LHC. The cross sections are reported as functions of jet multiplicity, jet transverse momentum pT, jet rapidity, the scalar pT sum of the jets, and angular correlations between the muon and each jet for different jet multiplicities. The measured cross sections are in agreement with predictions that include multileg leading-order (LO) and next-to-LO matrix element calculations interfaced with parton showers, as well as a next-to-next-to-LO calculation for the W boson and one jet production.

Metabolism of levamisole and kinetics of levamisole and aminorex in urine by means of LC-QTOF-HRMS and LC-QqQ-MS.

PubMed

Hess, Cornelius; Ritke, Natalie; Broecker, Sebastian; Madea, Burkhard; Musshoff, Frank

2013-05-01

The antihelminthic drug Levamisole can enhance cocaine effects by conversion into the amphetamine-like drug aminorex. We describe an LC-MS method for the determination of levamisole and its metabolite aminorex in human urine. Selectivity is given, calibration curves were linear within the calibration range 2.5-250 ng/mL; limits of the method were LoD 0.51 ng/mL, LoQ 1.02 ng/mL for levamisole and LoD 0.65 ng/mL, LoQ 0.76 ng/mL for aminorex. Precision data was in accordance with the guidelines (intraday precision for aminorex ranged between 5.75 and 11.0 % for levamisole between 8.36 and 10.9 %; interday precision for levamisole 10.9-16.9 % and for aminorex 7.64-12.7 %; accuracy data for levamisole -1.96 to -14.3 % and for aminorex-11.9 to-18.5 %). The validated method was successfully applied to study the urinary excretion of levamisole after the administration of 100 mg of levamisole orally. Levamisole and aminorex could be detected in post-administration urine samples. Levamisole could be detected up to 39 h after ingestion, while aminorex was detectable up to 54 h. Maximum aminorex concentrations were 45 ng/mL urine. Further metabolites of levamisole after oral ingestion by means of liquid chromatography hybrid quadrupole time-of-flight high-resolution mass spectrometry (LC-QTOF-HRMS) were identified. Only 0.5 % of the ingested drug was quantified as unchanged levamisole in urine. Besides aminorex, five isomers of aminorex and 4 hydroxy-metabolites of aminorex or its isomers were found. Furthermore, levamisole is also hydroxylated and eliminated free or conjugated with sulfate or glucuronide into urine.

Using Affordable Data Capturing Devices for Automatic 3d City Modelling

NASA Astrophysics Data System (ADS)

Alizadehashrafi, B.; Abdul-Rahman, A.

2017-11-01

In this research project, many movies from UTM Kolej 9, Skudai, Johor Bahru (See Figure 1) were taken by AR. Drone 2. Since the AR drone 2.0 has liquid lens, while flying there were significant distortions and deformations on the converted pictures of the movies. Passive remote sensing (RS) applications based on image matching and Epipolar lines such as Agisoft PhotoScan have been tested to create the point clouds and mesh along with 3D models and textures. As the result was not acceptable (See Figure 2), the previous Dynamic Pulse Function based on Ruby programming language were enhanced and utilized to create the 3D models automatically in LoD3. The accuracy of the final 3D model is almost 10 to 20 cm. After rectification and parallel projection of the photos based on some tie points and targets, all the parameters were measured and utilized as an input to the system to create the 3D model automatically in LoD3 in a very high accuracy.

Bond-orientational order in liquid Si

NASA Technical Reports Server (NTRS)

Wang, Z. Q.; Stroud, D.

1991-01-01

Bond-orientational order in liquid Si via Monte Carlo simulation in conjuncation with empirical two- and three-body potentials of the form proposed by Stillinger and Weber are studied. Bond-orientational order (BOO) is described in terms of combinations of spherical harmonic functions. Liquid Si is found to have pronounced short-range BOO corresponding to l = 3, as expected for a structure with local tetrahedral order. No long-range BOO is found either in the equilibrium or the supercooled liquid. When the three-body potential is artificially removed, the tetrahedral bond-orientation order disappears and the liquid assumes a close-packed structure.

Survey of Advanced Booster Options for Potential Shuttle Derivative Vehicles

NASA Technical Reports Server (NTRS)

Sackheim, Robert L.; Ryan, Richard; Threet, Ed; Kennedy, James W. (Technical Monitor)

2001-01-01

A never-ending major goal for the Space Shuttle program is to continually improve flight safety, as long as this launch system remains in operational service. One of the options to improve system safety and to enhance vehicle performance as well, that has been seriously studied over the past several decades, is to replace the existing strap-on four segment solid rocket boosters (SRB's) with more capable units. A number of booster upgrade options have been studied in some detail, ranging from five segment solids through hybrids and a wide variety of liquid strap-ons (both pressure and pump fed with various propellants); all the way to a completely reusable liquid fly back booster (complete with air breathing engines for controlled landing and return). All of these possibilities appear to offer improvements in varying degrees; and each has their strengths and weaknesses from both programmatic and technical points of view. The most beneficial booster upgrade/design, if the shuttle program were to continue long enough to justify the required investment, would be an approach that greatly increased both vehicle and crew safety. This would be accomplished by increasing the minimum range/minimum altitude envelope that would readily allow abort to orbit (ATO), possibly even to zero/zero, and possibly reduce or eliminate the Return to Launch Site (RTLS) and even the Trans Atlantic Landing (TAL) abort mode requirements. This paper will briefly survey and discuss all of the various booster'upgrade options studied previously, and compare their relative attributes. The survey will explicitly discuss, in summary comparative form, options that include: five segment solids; several hybrid possibilities; pressure and/or pump-fed liquids using either LO2/kerosene, H2O/kerosene and LO2/J2, any of which could be either fully expendable, partly or fully reusable; and finally a fully reusable liquid fly back booster system, with a number of propellant and propulsion system options. Performance and configuration comparison illustrations and tables will be included to provide a comprehensive survey for the paper.

Zero Boil-Off System Testing

NASA Technical Reports Server (NTRS)

Plachta, David W.; Johnson, Wesley L.; Feller, Jeffrey R.

2015-01-01

Cryogenic propellants such as liquid hydrogen (LH2) and liquid oxygen (LO2) are a part of NASA's future space exploration due to their high specific impulse for rocket motors of upper stages suitable for transporting 10s to 100s of metric tons of payload mass to destinations outside of low earth orbit and for their return. However, the low storage temperatures of LH2 and LO2 cause substantial boil-off losses for missions with durations greater than several months. These losses can be eliminated by incorporating high performance cryocooler technology to intercept heat load to the propellant tanks and modulating the cryocooler to control tank pressure. The active thermal control technology being developed by NASA is the reverse turbo-Brayton cycle cryocooler and its integration to the propellant tank through a distributed cooling tubing network coupled to the tank wall. This configuration was recently tested at NASA Glenn Research Center, in a vacuum chamber and cryoshroud that simulated the essential thermal aspects of low Earth orbit, its vacuum and temperature. Testing consisted of three passive tests with the active cryocooler system off, and 7 active tests, with the cryocooler powered up. The test matrix included zero boil-off tests performed at 90 full and 25 full, and several demonstrations at excess cooling capacity and reduced cooling capacity. From this, the tank pressure response with varied cryocooler power inputs was determined. This test series established that the active cooling system integrated with the propellant tank eliminated boil-off and robustly controlled tank pressure.

Effects of carbohydrate availability on sustained shivering I. Oxidation of plasma glucose, muscle glycogen, and proteins.

PubMed

Haman, François; Peronnet, François; Kenny, Glen P; Doucet, Eric; Massicotte, Denis; Lavoie, Carole; Weber, Jean-Michel

2004-01-01

Carbohydrates (CHO) can play an important thermogenic role during shivering, but the effect of their availability on the use of other oxidative fuels is unclear. Using indirect calorimetry and tracer methods ([U-13C]glucose ingestion), we have determined the specific contributions of plasma glucose, muscle glycogen, proteins, and lipids to total heat production (Hprod) in men exposed to cold for 2-h (liquid-conditioned suit perfused with 10 degrees C water). Measurements were made after low-CHO diet and exercise (Lo) and high-CHO diet without exercise (Hi). The size of CHO reserves had no effect on Hprod but a major impact on fuel selection before and during shivering. In the cold, a complete shift from lipid oxidation for Lo (53, 28, and 19% Hprod for lipids, CHO, and proteins, respectively) to CHO-based metabolism for Hi (23, 65, and 12% Hprod for lipids, CHO, and proteins, respectively) was observed. Plasma glucose oxidation remains a minor fuel under all conditions (<13% Hprod), falling to 7% Hprod for Lo. Therefore, adjusting plasma glucose oxidation to compensate for changes in muscle glycogen oxidation is not a strategy used for maintaining heat production. Instead, proteins and lipids share responsibility for this compensation. We conclude that humans can show remarkable flexibility in oxidative fuel selection to ensure that heat production is not compromised during sustained cold exposure.

Evolution of short range order in Ar: Liquid to glass and solid transitions-A computational study

NASA Astrophysics Data System (ADS)

Shor, Stanislav; Yahel, Eyal; Makov, Guy

2018-04-01

The evolution of the short range order (SRO) as a function of temperature in a Lennard-Jones model liquid with Ar parameters was determined and juxtaposed with thermodynamic and kinetic properties obtained as the liquid was cooled (heated) and transformed between crystalline solid or glassy states and an undercooled liquid. The Lennard-Jones system was studied by non-equilibrium molecular dynamics simulations of large supercells (approximately 20000 atoms) rapidly cooled or heated at selected quenching rates and at constant pressure. The liquid to solid transition was identified by discontinuities in the atomic volume and molar enthalpy; the glass transition temperature range was identified from the temperature dependence of the self-diffusion. The SRO was studied within the quasi-crystalline model (QCM) framework and compared with the Steinhardt bond order parameters. Within the QCM it was found that the SRO evolves from a bcc-like order in the liquid through a bct-like short range order (c/a=1.2) in the supercooled liquid which persists into the glass and finally to a fcc-like ordering in the crystalline solid. The variation of the SRO that results from the QCM compares well with that obtained with Steinhardt's bond order parameters. The hypothesis of icosahedral order in liquids and glasses is not supported by our results.

Correction of partial volume effect in (18)F-FDG PET brain studies using coregistered MR volumes: voxel based analysis of tracer uptake in the white matter.

PubMed

Coello, Christopher; Willoch, Frode; Selnes, Per; Gjerstad, Leif; Fladby, Tormod; Skretting, Arne

2013-05-15

A voxel-based algorithm to correct for partial volume effect in PET brain volumes is presented. This method (named LoReAn) is based on MRI based segmentation of anatomical regions and accurate measurements of the effective point spread function of the PET imaging process. The objective is to correct for the spill-out of activity from high-uptake anatomical structures (e.g. grey matter) into low-uptake anatomical structures (e.g. white matter) in order to quantify physiological uptake in the white matter. The new algorithm is presented and validated against the state of the art region-based geometric transfer matrix (GTM) method with synthetic and clinical data. Using synthetic data, both bias and coefficient of variation were improved in the white matter region using LoReAn compared to GTM. An increased number of anatomical regions doesn't affect the bias (<5%) and misregistration affects equally LoReAn and GTM algorithms. The LoReAn algorithm appears to be a simple and promising voxel-based algorithm for studying metabolism in white matter regions. Copyright © 2013 Elsevier Inc. All rights reserved.

Multiphonon Raman scattering and photoluminescence studies of CdS nanocrystals grown by thermal evaporation

NASA Astrophysics Data System (ADS)

Farid, Sidra; Stroscio, Michael A.; Dutta, Mitra

2018-03-01

Thermal evaporation growth technique is presented as a route to grow cost effective high quality CdS thin films. We have successfully grown high quality CdS thin films on ITO coated glass substrates by thermal evaporation technique and analyzed the effects of annealing and excitation dependent input of CdS thin film using Raman and photoluminescence spectroscopy. LO phonon modes have been analyzed quantitatively considering the contributions due to anneal induced effects on film quality using phonon spatial correlation model, line shape and defect state analysis. Asymmetry in the Raman line shape towards the low frequency side is related to the phonon confinement effects and is modeled by spatial correlation model. Calculations of width (FWHM), integrated intensity, and line shape for the longitudinal (LO) optical phonon modes indicate improved crystalline quality for the annealed films as compared to the as grown films. With increase in laser power, intensity ratio of 2-LO to 1-LO optical phonon modes is found to increase while multiple overtones upto fourth order are observed. Power dependent photoluminescence data indicates direct band-to-band transition in CdS thin films.

Λ N → NN EFT potentials and hypertriton non-mesonic weak decay

NASA Astrophysics Data System (ADS)

Pérez-Obiol, Axel; Entem, David R.; Nogga, Andreas

2018-05-01

The potential for the Λ N → NN weak transition, the main responsible for the non-mesonic weak decay of hypernuclei, has been developed within the framework of effective field theory (EFT) up to next-to-leading order (NLO). The leading order (LO) and NLO contributions have been calculated in both momentum and coordinate space, and have been organised into the different operators which mediate the N → NN transition. We compare the ranges of the one-meson and two-pion exchanges for each operator. The non-mesonic weak decay of the hypertriton has been computed within the plane-wave approximation using the LO weak potential and modern strong EFT NN potentials. Formally, two methods to calculate the final state interactions among the decay products are presented. We briefly comment on the calculation of the {}{{Λ }}{}3H{\\to }3 He+{π }- mesonic weak decay.

Solution of QCD⊗QED coupled DGLAP equations at NLO

NASA Astrophysics Data System (ADS)

Zarrin, S.; Boroun, G. R.

2017-09-01

In this work, we present an analytical solution for QCD⊗QED coupled Dokshitzer-Gribov-Lipatov-Altarelli-Parisi (DGLAP) evolution equations at the leading order (LO) accuracy in QED and next-to-leading order (NLO) accuracy in perturbative QCD using double Laplace transform. This technique is applied to obtain the singlet, gluon and photon distribution functions and also the proton structure function. We also obtain contribution of photon in proton at LO and NLO at high energy and successfully compare the proton structure function with HERA data [1] and APFEL results [2]. Some comparisons also have been done for the singlet and gluon distribution functions with the MSTW results [3]. In addition, the contribution of photon distribution function inside the proton has been compared with results of MRST [4] and with the contribution of sea quark distribution functions which obtained by MSTW [3] and CTEQ6M [5].

DOE Office of Scientific and Technical Information (OSTI.GOV)

Anastasiou, Charalampos; Duhr, Claude; Dulat, Falko

We present methods to compute higher orders in the threshold expansion for the one-loop production of a Higgs boson in association with two partons at hadron colliders. This process contributes to the N 3LO Higgs production cross section beyond the soft-virtual approximation. We use reverse unitarity to expand the phase-space integrals in the small kinematic parameters and to reduce the coefficients of the expansion to a small set of master integrals. We describe two methods for the calculation of the master integrals. The first was introduced for the calculation of the soft triple-real radiation relevant to N 3LO Higgs production.more » The second uses a particular factorization of the three body phase-space measure and the knowledge of the scaling properties of the integral itself. Our result is presented as a Laurent expansion in the dimensional regulator, although some of the master integrals are computed to all orders in this parameter.« less

Longitudinal structure function from logarithmic slopes of F2 at low x

NASA Astrophysics Data System (ADS)

Boroun, G. R.

2018-01-01

Using Laplace transform techniques, I calculate the longitudinal structure function FL(x ,Q2) from the scaling violations of the proton structure function F2(x ,Q2) and make a critical study of this relationship between the structure functions at leading order (LO) up to next-to-next-to leading order (NNLO) analysis at small x . Furthermore, I consider heavy quark contributions to the relation between the structure functions, which leads to compact formula for Nf=3 +Heavy . The nonlinear corrections to the longitudinal structure function at LO up to NNLO analysis are shown in the Nf=4 (light quark flavor) based on the nonlinear corrections at R =2 and R =4 GeV-1 . The results are compared with experimental data of the longitudinal proton structure function FL in the range of 6.5 ≤Q2≤800 GeV2 .

Modelling Limit Order Execution Times from Market Data

NASA Astrophysics Data System (ADS)

Kim, Adlar; Farmer, Doyne; Lo, Andrew

2007-03-01

Although the term ``liquidity'' is widely used in finance literatures, its meaning is very loosely defined and there is no quantitative measure for it. Generally, ``liquidity'' means an ability to quickly trade stocks without causing a significant impact on the stock price. From this definition, we identified two facets of liquidity -- 1.execution time of limit orders, and 2.price impact of market orders. The limit order is an order to transact a prespecified number of shares at a prespecified price, which will not cause an immediate execution. On the other hand, the market order is an order to transact a prespecified number of shares at a market price, which will cause an immediate execution, but are subject to price impact. Therefore, when the stock is liquid, market participants will experience quick limit order executions and small market order impacts. As a first step to understand market liquidity, we studied the facet of liquidity related to limit order executions -- execution times. In this talk, we propose a novel approach of modeling limit order execution times and show how they are affected by size and price of orders. We used q-Weibull distribution, which is a generalized form of Weibull distribution that can control the fatness of tail to model limit order execution times.

Measuring the Outflow Properties of FeLoBAL Quasars

NASA Astrophysics Data System (ADS)

Dabbieri, Collin; Choi, Hyunseop; MacInnis, Francis; Leighly, Karen; Terndrup, Donald

2018-01-01

Roughly 20 percent of the quasar population shows broad absorption lines, which are indicators of an energetic wind. Within the broad absorption line class of quasars exist FeLoBAL quasars, which show strong absorption lines from the Fe II and Fe III transitions as well as other low-ionization lines. FeLoBALs are of particular interest because they are thought to possibly be a short-lived stage in a quasar's life where it expels its shroud of gas and dust. This means the winds we see from FeLoBALs are one manifestation of galactic feedback. This idea is supported by Farrah et al. (2012) who found an anti correlation between outflow strength and contribution from star formation to the total IR luminosity of the host galaxy when examining a sample of FeLoBAL quasars. We analyze the sample of 26 FeLoBALs from Farrah et al. (2012) in order to measure the properties of their outflows, including ionization, density, column density and covering fraction. The absorption and continuum profiles of these objects are modeled using SimBAL, a program which creates synthetic spectra using a grid of Cloudy models. A Monte-Carlo method is employed to determine posterior probabilities for the physical parameters of the outflow. From these probabilities we extract the distance of the outflow, the mass outflow rate and the kinetic luminosity. We demonstrate SimBAL is capable of modeling a wide range of spectral morphologies. From the 26 objects studied we observe interesting correlations between ionization parameter, distance and density. Analysis of our sample also suggests a dearth of objects with velocity widths greater than or equal to 300 km/s at distances greater than or equal to 100 parsecs.

Lessons Learned from the Design, Certification, and Operation of the Space Shuttle Integrated Main Propulsion System (IMPS)

NASA Technical Reports Server (NTRS)

Martinez, Hugo E.; Albright, John D.; D'Amico, Stephen J.; Brewer, John M.; Melcher, John C., IV

2011-01-01

The Space Shuttle Integrated Main Propulsion System (IMPS) consists of the External Tank (ET), Orbiter Main Propulsion System (MPS), and Space Shuttle Main Engines (SSMEs). The IMPS is tasked with the storage, conditioning, distribution, and combustion of cryogenic liquid hydrogen (LH2) and liquid oxygen (LO2) propellants to provide first and second stage thrust for achieving orbital velocity. The design, certification, and operation of the associated IMPS hardware have produced many lessons learned over the course of the Space Shuttle Program (SSP). A subset of these items will be discussed in this paper for consideration when designing, building, and operating future spacecraft propulsion systems. This paper will focus on lessons learned related to Orbiter MPS and is the first of a planned series to address the subject matter.

Analysis of Space Shuttle Ground Support System Fault Detection, Isolation, and Recovery Processes and Resources

NASA Technical Reports Server (NTRS)

Gross, Anthony R.; Gerald-Yamasaki, Michael; Trent, Robert P.

2009-01-01

As part of the FDIR (Fault Detection, Isolation, and Recovery) Project for the Constellation Program, a task was designed within the context of the Constellation Program FDIR project called the Legacy Benchmarking Task to document as accurately as possible the FDIR processes and resources that were used by the Space Shuttle ground support equipment (GSE) during the Shuttle flight program. These results served as a comparison with results obtained from the new FDIR capability. The task team assessed Shuttle and EELV (Evolved Expendable Launch Vehicle) historical data for GSE-related launch delays to identify expected benefits and impact. This analysis included a study of complex fault isolation situations that required a lengthy troubleshooting process. Specifically, four elements of that system were considered: LH2 (liquid hydrogen), LO2 (liquid oxygen), hydraulic test, and ground special power.

Liquidity Dynamics in the Xetra Order Book

NASA Astrophysics Data System (ADS)

Schmidinger, Christoph

2010-09-01

In this paper we show how to reconstruct the limit order book of the 30 stocks constituting the DAX30 index based on the trading protocol of the Xetra Trading System at the Frankfurt Stock Exchange. The algorithm used is innovative as it captures all trading phases, including auctions, and delivers a reconstruction of the orderbook either from a trader's view or a supervisory view including hidden volume as well. Based on the rebuilt order book, liquidity dynamics are examined. In contrats to findings for dealer markets, past market returns play a minor role in the determination of liquidity and liquidity commonality in Xetra, a pure limit order book market. Consequently, we provide evidence that liquidity provision by multiple sources in Xetra mitigates systemic liquidity risk introduced by the interrelation of return and liquidity.

Experimental Verification and Revision of the Venting Rate Model of the Hazard Assessment Computer System and the Vulnerability Model.

DTIC Science & Technology

1980-11-01

discharge of a nonvolatile liquid can be ob- tained by standard Bernoulli -type relations; it is: WLo = CDA LoPL (2[PT - P-/PL + - ZLh) 1/ (1110) In all...cargo outflow momentum is low (i.e., when the net positive pressure differ- ence across the puncture is near zero). The tests showed that the water...34Benedict-Webb- Rubin Ecuation of State for Methane at Cryogenic Condi- tions," Advances -in Crvccenic ’Encineerinc., 14, po. 49-54, Plen=m Press, 1969

The reversibility and first-order nature of liquid–liquid transition in a molecular liquid

PubMed Central

Kobayashi, Mika; Tanaka, Hajime

2016-01-01

Liquid–liquid transition is an intriguing phenomenon in which a liquid transforms into another liquid via the first-order transition. For molecular liquids, however, it always takes place in a supercooled liquid state metastable against crystallization, which has led to a number of serious debates concerning its origin: liquid–liquid transition versus unusual nano-crystal formation. Thus, there have so far been no single example free from such debates, to the best of our knowledge. Here we show experimental evidence that the transition is truly liquid–liquid transition and not nano-crystallization for a molecular liquid, triphenyl phosphite. We kinetically isolate the reverse liquid-liquid transition from glass transition and crystallization with a high heating rate of flash differential scanning calorimetry, and prove the reversibility and first-order nature of liquid–liquid transition. Our finding not only deepens our physical understanding of liquid–liquid transition but may also initiate a phase of its research from both fundamental and applications viewpoints. PMID:27841349

Liquid oxygen/liquid hydrogen auxiliary power system thruster investigation

NASA Technical Reports Server (NTRS)

Eberle, E. E.; Kusak, L.

1979-01-01

The design, fabrication, and demonstration of a 111 newton (25 lb) thrust, integrated auxiliary propulsion system (IAPS) thruster for use with LH2/LO2 propellants is described. Hydrogen was supplied at a temperature range of 22 to 33 K (40 to 60 R), and oxygen from 89 to 122 K (160 to 220 R). The thruster was designed to operate in both pulse mode and steady-state modes for vehicle attitude control, space maneuvering, and as an abort backup in the event of failure of the main propulsion system. A dual-sleeve, tri-axial injection system was designed that utilizes a primary injector/combustor where 100 percent of the oxygen and 8 percent of the hydrogen is introduced; a secondary injector/combustor where 45 percent of the hydrogen is introduced to mix with the primary combustor gases; and a boundary layer injector that uses the remaining 45 percent of the hydrogen to cool the thrust throat/nozzle design. Hot-fire evaluation of this thruster with a BLC injection distance of 2.79 cm (1.10 in.) indicated that a specific impulse value of 390 sec can be attained using a coated molybdenum thrust chamber. Pulse mode tests indicated that a chamber pressure buildup to 90 percent thrust can be achieved in a time on the order of 48 msec. Some problems were encountered in achieving ignition of each pulse during pulse trains. This was interpreted to indicate that a higher delivered spark energy level ( 100 mJ) would be required to maintain ignition reliability of the plasma torch ignition system under the extra 'cold' conditions resulting during pulsing.

Phase separations in mixtures of a liquid crystal and a nanocolloidal particle.

PubMed

Matsuyama, Akihiko

2009-11-28

We present a mean field theory to describe phase separations in mixtures of a liquid crystal and a nanocolloidal particle. By taking into account a nematic, a smectic A ordering of the liquid crystal, and a crystalline ordering of the nanoparticle, we calculate the phase diagrams on the temperature-concentration plane. We predict various phase separations, such as a smectic A-crystal phase separation and a smectic A-isotropic-crystal triple point, etc., depending on the interactions between the liquid crystal and the colloidal surface. Inside binodal curves, we find new unstable and metastable regions, which are important in the phase ordering dynamics. We also find a crystalline ordering of the nanoparticles dispersed in a smectic A phase and a nematic phase. The cooperative phenomena between liquid-crystalline ordering and crystalline ordering induce a variety of phase diagrams.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kung, C. C.; Kramer, G. J.; Johnson, E.

Reflectometry, which uses the microwave radar technique to probe the magnetically confined fusion plasmas, is a very powerful tool to observe the density fluctuations in the fusion plasmas. Typically, two or more microwave beams of different frequencies are used to study the plasma density fluctuations. The frequency separation between these two beams of the PPPL designed reflectometer system upgrade on the DIII-D tokamak can be varied over 18 GHz. Due to the performance of the associated electronics, the local oscillator (LO) power level at the LO port of the I/Q demodulator suffers more than 12 dB of power fluctuations whenmore » the frequency separation is varied. Thus, the I/Q demodulator performance is impaired. In order to correct this problem, a power leveling circuit is introduced in the PPPL upgrade. According to the test results, the LO power fluctuation was regulated to be within 1 dB for greater than 16 dB of input power variation over the full dynamic bandwidth of the receiver.« less

Design and performance evaluations of a LO2/methane reaction control engine

NASA Astrophysics Data System (ADS)

Johnson, Aaron

Liquid oxygen (LOX) and liquid methane (LCH4) are a propellant combination viewed as a potential enabling technology for spacecraft propulsion. Reasons why LOX/LCH4 is being used as an alternative propellant source include: it is less toxic than other propellants, it has the possibility to be harvested on extraterrestrial soil, LCH4 has a higher energy density than liquid hydrogen (LH2; commonly used on vehicle main engines), and LOX/LCH4 has comparable performance to other well-known propellant combinations. Through the continued partnership between the National Aeronautics and Space Administration (NASA) and the University of Texas at El Paso (UTEP) a LOX/LCH4 reaction control engine (RCE) was developed and researched. The RCE was developed for the purpose of being integrated into two UTEP LOX/LCH4 vehicles, Janus and Daedalus, and was designed based on previous engines tested both at NASA and the center for space exploration and technology research (cSETR) lab. This report details the design process and manufacturing of the engine, cold flow studies evaluating injector design, and preliminary hot fire tests to give insight into engine performance.

Mathematical Model of Bubble Sloshing Dynamics for Cryogenic Liquid Helium in Orbital Spacecraft Dewar Container

NASA Technical Reports Server (NTRS)

Hung, R. J.; Pan, H. L.

1995-01-01

A generalized mathematical model is investigated of sloshing dynamics for dewar containers, partially filled with a liquid of cryogenic superfluid helium 2, driven by both gravity gradient and jitter accelerations applicable to two types of scientific spacecrafts, which are eligible to carry out spinning motion and/or slew motion to perform scientific observations during normal spacecraft operation. Two examples are given for the Gravity Probe-B (GP-B) with spinning motion, and the Advanced X-Ray Astrophysics Facility-Spectroscopy (AXAF-S) with slew motion, which are responsible for the sloshing dynamics. Explicit mathematical expressions for the modelling of sloshing dynamics to cover these forces acting on the spacecraft fluid systems are derived. The numerical computation of sloshing dynamics will be based on the noninertial frame spacecraft bound coordinate, and we will solve the time-dependent three-dimensional formulations of partial differential equations subject to initial and boundary conditions. Explicit mathematical expressions of boundary conditions lo cover capillary force effects on the liquid-vapor interface in microgravity environments are also derived. Results of the simulations of the mathematical model are illustrated.

Independent Orbiter Assessment (IOA): Assessment of the orbiter main propulsion system FMEA/CIL, volume 1

NASA Technical Reports Server (NTRS)

Slaughter, B. C.

1988-01-01

The results of the Independent Orbiter Assessment (IOA) of the Failure Modes and Effects Analysis (FMEA) and Critical Items List (CIL) are presented. The IOA effort first completed an analysis of the Main Propulsion System (MPS) hardware, generating draft failure modes and potential critical items. To preserve independence, this analysis was accomplished without reliance upon the results contained within the NASA FMEA/CIL documentation. The IOA results were then compared to available data from the Rockwell Downey/NASA JSC FMEA/CIL review. The Orbiter MPS is composed of the Propellant Management Subsystem (PMS) consisting of the liquid oxygen (LO2) and liquid hydrogen (LH2) subsystems and the helium subsystem. The PMS is a system of manifolds, distribution lines, and valves by which the liquid propellants pass from the External Tank to the Space Shuttle Main Engine (SSME). The helium subsystem consists of a series of helium supply tanks and their associated regulators, control valves, and distribution lines. Volume 1 contains the MPS description, assessment results, ground rules and assumptions, and some of the IOA worksheets.

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Federal Register 2010, 2011, 2012, 2013, 2014

2012-09-14

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Federal Register 2010, 2011, 2012, 2013, 2014

2013-10-02

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Development of Balanced SIS Mixers for ALMA Band-10

NASA Astrophysics Data System (ADS)

Shitov, Sergey V.; Koryukin, Oleg V.; Uzawa, Yoshinory; Noguchi, Takashi; Uvarov, Andrey V.; Cohn, Ilya A.

2006-05-01

A few concepts of a wide-band balanced SIS mixer employing submicron-sized SIS junctions are under development for 787-950 GHz frequency range. A quasioptical DSB balanced mixer with integrated cross-slot antenna is considered as the less laborious and cheaper option. The silicon lens-antenna beam efficiency is expected above 80 % across the whole band with first-order sidelobe below -16 dB. To use the conservative horn antenna solution, a single chamber waveguide DSB balanced mixer is developed. Two equal probe-type SIS chips are inserted into a full-height waveguide through its opposite broad walls; these two mixers are driven by the signal waveguide in series. The LO current is transferred to the mixers in parallel via a capacitive probe inserted through the narrow wall of the signal waveguide from the neighboring LO waveguide. The HFSS model demonstrated the LO power coupling efficiency above -3 dB, almost perfect signal transfer and the LO cross talk below -30 dB that take into account misalignment (misbalance) of the chips. It is demonstrated numerically using Tucker's 3-port model that unequal pump of junctions of a twin-SIS mixer can lead, in spite of the perfect signal coupling, to degradation of the gain performance up to -3 dB, especially at the top of the ALMA Band-10.

Differential Higgs production at N3LO beyond threshold

NASA Astrophysics Data System (ADS)

Dulat, Falko; Mistlberger, Bernhard; Pelloni, Andrea

2018-01-01

We present several key steps towards the computation of differential Higgs boson cross sections at N3LO in perturbative QCD. Specifically, we work in the framework of Higgs-differential cross sections that allows to compute precise predictions for realistic LHC observables. We demonstrate how to perform an expansion of the analytic N3LO coefficient functions around the production threshold of the Higgs boson. Our framework allows us to compute to arbitrarily high order in the threshold expansion and we explicitly obtain the first two expansion coefficients in analytic form. Furthermore, we assess the phenomenological viability of threshold expansions for differential distributions. We find that while a few terms in the threshold expansion are sufficient to approximate the exact rapidity distribution well, transverse momentum distributions require a signficantly higher number of terms in the expansion to be adequately described. We find that to improve state of the art predictions for the rapidity distribution beyond NNLO even more sub-leading terms in the threshold expansion than presented in this article are required. In addition, we report on an interesting obstacle for the computation of N3LO corrections with LHAPDF parton distribution functions and our solution. We provide files containing the analytic expressions for the partonic cross sections as supplementary material attached to this paper.

Differential Higgs production at N 3LO beyond threshold

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dulat, Falko; Mistlberger, Bernhard; Pelloni, Andrea

We present several key steps towards the computation of differential Higgs boson cross sections at N 3LO in perturbative QCD. Specifically, we work in the framework of Higgs-differential cross sections that allows to compute precise predictions for realistic LHC observables. We demonstrate how to perform an expansion of the analytic N 3LO coefficient functions around the production threshold of the Higgs boson. Our framework allows us to compute to arbitrarily high order in the threshold expansion and we explicitly obtain the first two expansion coefficients in analytic form. Furthermore, we assess the phenomenological viability of threshold expansions for differential distributions.more » We find that while a few terms in the threshold expansion are sufficient to approximate the exact rapidity distribution well, transverse momentum distributions require a signficantly higher number of terms in the expansion to be adequately described. We find that to improve state of the art predictions for the rapidity distribution beyond NNLO even more sub-leading terms in the threshold expansion than presented in this article are required. In addition, we report on an interesting obstacle for the computation of N 3LO corrections with LHAPDF parton distribution functions and our solution. We provide files containing the analytic expressions for the partonic cross sections as supplementary material attached to this paper.« less

Differential Higgs production at N 3LO beyond threshold

DOE PAGES

Dulat, Falko; Mistlberger, Bernhard; Pelloni, Andrea

2018-01-29

We present several key steps towards the computation of differential Higgs boson cross sections at N 3LO in perturbative QCD. Specifically, we work in the framework of Higgs-differential cross sections that allows to compute precise predictions for realistic LHC observables. We demonstrate how to perform an expansion of the analytic N 3LO coefficient functions around the production threshold of the Higgs boson. Our framework allows us to compute to arbitrarily high order in the threshold expansion and we explicitly obtain the first two expansion coefficients in analytic form. Furthermore, we assess the phenomenological viability of threshold expansions for differential distributions.more » We find that while a few terms in the threshold expansion are sufficient to approximate the exact rapidity distribution well, transverse momentum distributions require a signficantly higher number of terms in the expansion to be adequately described. We find that to improve state of the art predictions for the rapidity distribution beyond NNLO even more sub-leading terms in the threshold expansion than presented in this article are required. In addition, we report on an interesting obstacle for the computation of N 3LO corrections with LHAPDF parton distribution functions and our solution. We provide files containing the analytic expressions for the partonic cross sections as supplementary material attached to this paper.« less

Validation and comparison of two NGS assays for the detection of EGFR T790M resistance mutation in liquid biopsies of NSCLC patients.

PubMed

Vollbrecht, Claudia; Lehmann, Annika; Lenze, Dido; Hummel, Michael

2018-04-06

Analysis of circulating cell-free DNA (cfDNA) derived from peripheral blood ("liquid biopsy") is an attractive alternative to identify non-small cell lung cancer (NSCLC) patients with the EGFR T790M mutation eligible for 3rd generation tyrosine kinase inhibitor therapy. We evaluated two PCR-based next generation sequencing (NGS) approaches, one including unique molecular identifiers (UMI), with focus on highly sensitive EGFR T790M mutation detection. Therefore, we extracted and sequenced cfDNA from synthetic plasma samples spiked with mutated DNA at decreasing allele frequencies and from 21 diagnostic NSCLC patients. Data evaluation was performed to determine the limit of detection (LoD), accuracy, specificity and sensitivity of both assays. Considering all tested reference dilutions and mutations the UMI assay performed best in terms of LoD (1% vs. 5%), sensitivity (95.8% vs. 81.3%), specificity (100% vs. 93.8%) and accuracy (96.9% vs. 84.4%). Comparing mutation status of diagnostic samples with both assays showed 81.3% concordance with primary mutation verifiable in 52% of cases. EGFR T790M was detected concordantly in 6/7 patients with allele frequencies from 0.1% to 27%. In one patient, the T790M mutation was exclusively detectable with the UMI assay. Our data demonstrate that both assays are applicable as multi-biomarker NGS tools enabling the simultaneous detection of primary EGFR driver and resistance mutations. However, for mutations with low allelic frequencies the use of NGS panels with UMI facilitates a more sensitive and reliable detection.

Validation and comparison of two NGS assays for the detection of EGFR T790M resistance mutation in liquid biopsies of NSCLC patients

PubMed Central

Vollbrecht, Claudia; Lehmann, Annika; Lenze, Dido; Hummel, Michael

2018-01-01

Analysis of circulating cell-free DNA (cfDNA) derived from peripheral blood (“liquid biopsy”) is an attractive alternative to identify non-small cell lung cancer (NSCLC) patients with the EGFR T790M mutation eligible for 3rd generation tyrosine kinase inhibitor therapy. We evaluated two PCR-based next generation sequencing (NGS) approaches, one including unique molecular identifiers (UMI), with focus on highly sensitive EGFR T790M mutation detection. Therefore, we extracted and sequenced cfDNA from synthetic plasma samples spiked with mutated DNA at decreasing allele frequencies and from 21 diagnostic NSCLC patients. Data evaluation was performed to determine the limit of detection (LoD), accuracy, specificity and sensitivity of both assays. Considering all tested reference dilutions and mutations the UMI assay performed best in terms of LoD (1% vs. 5%), sensitivity (95.8% vs. 81.3%), specificity (100% vs. 93.8%) and accuracy (96.9% vs. 84.4%). Comparing mutation status of diagnostic samples with both assays showed 81.3% concordance with primary mutation verifiable in 52% of cases. EGFR T790M was detected concordantly in 6/7 patients with allele frequencies from 0.1% to 27%. In one patient, the T790M mutation was exclusively detectable with the UMI assay. Our data demonstrate that both assays are applicable as multi-biomarker NGS tools enabling the simultaneous detection of primary EGFR driver and resistance mutations. However, for mutations with low allelic frequencies the use of NGS panels with UMI facilitates a more sensitive and reliable detection. PMID:29719623

Sea-Level Flight Demonstration and Altitude Characterization of a LO2/LCH4 Based Accent Propulsion Lander

NASA Technical Reports Server (NTRS)

Collins, Jacob; Hurlbert, Eric; Romig, Kris; Melcher, John; Hobson, Aaron; Eaton, Phil

2009-01-01

A 1,500 lbf thrust-class liquid oxygen (LO2)/Liquid Methane (LCH4) rocket engine was developed and tested at both sea-level and simulated altitude conditions. The engine was fabricated by Armadillo Aerospace (AA) in collaboration with NASA Johnson Space Center. Sea level testing was conducted at Armadillo Aerospace facilities at Caddo Mills, TX. Sea-level tests were conducted using both a static horizontal test bed and a vertical take-off and landing (VTOL) test bed capable of lift-off and hover-flight in low atmosphere conditions. The vertical test bed configuration is capable of throttling the engine valves to enable liftoff and hover-flight. Simulated altitude vacuum testing was conducted at NASA Johnson Space Center White Sands Test Facility (WSTF), which is capable of providing altitude simulation greater than 120,000 ft equivalent. The engine tests demonstrated ignition using two different methods, a gas-torch and a pyrotechnic igniter. Both gas torch and pyrotechnic ignition were demonstrated at both sea-level and vacuum conditions. The rocket engine was designed to be configured with three different nozzle configurations, including a dual-bell nozzle geometry. Dual-bell nozzle tests were conducted at WSTF and engine performance data was achieved at both ambient pressure and simulated altitude conditions. Dual-bell nozzle performance data was achieved over a range of altitude conditions from 90,000 ft to 50,000 ft altitude. Thrust and propellant mass flow rates were measured in the tests for specific impulse (Isp) and C* calculations.

Liquid crystals of carbon nanotubes and graphene.

PubMed

Zakri, Cécile; Blanc, Christophe; Grelet, Eric; Zamora-Ledezma, Camilo; Puech, Nicolas; Anglaret, Eric; Poulin, Philippe

2013-04-13

Liquid crystal ordering is an opportunity to develop novel materials and applications with spontaneously aligned nanotubes or graphene particles. Nevertheless, achieving high orientational order parameter and large monodomains remains a challenge. In addition, our restricted knowledge of the structure of the currently available materials is a limitation for fundamental studies and future applications. This paper presents recent methodologies that have been developed to achieve large monodomains of nematic liquid crystals. These allow quantification and increase of their order parameters. Nematic ordering provides an efficient way to prepare conductive films that exhibit anisotropic properties. In particular, it is shown how the electrical conductivity anisotropy increases with the order parameter of the nematic liquid crystal. The order parameter can be tuned by controlling the length and entanglement of the nanotubes. In the second part of the paper, recent results on graphene liquid crystals are reported. The possibility to obtain water-based liquid crystals stabilized by surfactant molecules is demonstrated. Structural and thermodynamic characterizations provide indirect but statistical information on the dimensions of the graphene flakes. From a general point of view, this work presents experimental approaches to optimize the use of nanocarbons as liquid crystals and provides new methodologies for the still challenging characterization of such materials.

Organic Glasses with Tunable Liquid-Crystalline Order

NASA Astrophysics Data System (ADS)

Teerakapibal, Rattavut; Huang, Chengbin; Gujral, Ankit; Ediger, Mark D.; Yu, Lian

2018-02-01

Liquid crystals (LCs) are known to undergo rapid ordering transitions with virtually no hysteresis. We report a remarkable counterexample, itraconazole, where the nematic to smectic transition is avoided at a cooling rate exceeding 20 K /s . The smectic order trapped in a glass is the order reached by the equilibrium liquid before the kinetic arrest of the end-over-end molecular rotation. This is attributed to the fact that smectic ordering requires orientational ordering and suggests a general condition for preparing organic glasses with tunable LC order for electronic applications.

Lyotropic Liquid Crystal Phases from Anisotropic Nanomaterials

PubMed Central

Dierking, Ingo

2017-01-01

Liquid crystals are an integral part of a mature display technology, also establishing themselves in other applications, such as spatial light modulators, telecommunication technology, photonics, or sensors, just to name a few of the non-display applications. In recent years, there has been an increasing trend to add various nanomaterials to liquid crystals, which is motivated by several aspects of materials development. (i) addition of nanomaterials can change and thus tune the properties of the liquid crystal; (ii) novel functionalities can be added to the liquid crystal; and (iii) the self-organization of the liquid crystalline state can be exploited to template ordered structures or to transfer order onto dispersed nanomaterials. Much of the research effort has been concentrated on thermotropic systems, which change order as a function of temperature. Here we review the other side of the medal, the formation and properties of ordered, anisotropic fluid phases, liquid crystals, by addition of shape-anisotropic nanomaterials to isotropic liquids. Several classes of materials will be discussed, inorganic and mineral liquid crystals, viruses, nanotubes and nanorods, as well as graphene oxide. PMID:28974025

A micromethod for the determination of the new antiepileptic drug levetiracetam (ucb LO59) in serum or plasma by high performance liquid chromatography.

PubMed

Ratnaraj, N; Doheny, H C; Patsalos, P N

1996-04-01

An isocratic high performance liquid chromatographic micromethod is described for the quantitation of levetiracetam (ucb L059) in plasma or serum of patients. The chromatography is performed on a 250 x 4 mm I.D. LiChrospher 60 RP-select B, 5-micron column, eluted with an acetonitrile/50 mM phosphate buffer (15:85 vol/vol, pH 5.6) mobile phase, and levetiracetam detected using ultraviolet absorbance at 220 nm. The limit of quantitation was 5 mumol/L and the within-batch and between-batch coefficients of variation were < 7%. No interference from commonly prescribed antiepileptic drugs (carbamazepine and its metabolite carbamazepine epoxide, ethosuximide, gabapentin, lamotrigine, phenobarbitone, phenytoin, primidone, valproic acid, and vigabatrin) was observed, and thus the method can be used to monitor levetiracetam in patients on polytherapy antiepileptic drug regimens.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Patsha, Avinash, E-mail: avinash.phy@gmail.com, E-mail: dhara@igcar.gov.in; Dhara, Sandip; Tyagi, A. K.

The localized effect of impurities in single GaN nanowires in the sub-diffraction limit is reported using the study of lattice vibrational modes in the evanescent field of Au nanoparticle assisted tip enhanced Raman spectroscopy (TERS). GaN nanowires with the O impurity and the Mg dopants were grown by the chemical vapor deposition technique in the catalyst assisted vapor-liquid-solid process. Symmetry allowed Raman modes of wurtzite GaN are observed for undoped and doped nanowires. Unusually very strong intensity of the non-zone center zone boundary mode is observed for the TERS studies of both the undoped and the Mg doped GaN singlemore » nanowires. Surface optical mode of A{sub 1} symmetry is also observed for both the undoped and the Mg doped GaN samples. A strong coupling of longitudinal optical (LO) phonons with free electrons, however, is reported only in the O rich single nanowires with the asymmetric A{sub 1}(LO) mode. Study of the local vibration mode shows the presence of Mg as dopant in the single GaN nanowires.« less

Liquid Methane Conditioning Capabilities Developed at the NASA Glenn Research Center's Small Multi- Purpose Research Facility (SMiRF) for Accelerated Lunar Surface Storage Thermal Testing

NASA Technical Reports Server (NTRS)

Bamberger, Helmut H.; Robinson, R. Craig; Jurns, John M.; Grasl, Steven J.

2011-01-01

Glenn Research Center s Creek Road Cryogenic Complex, Small Multi-Purpose Research Facility (SMiRF) recently completed validation / checkout testing of a new liquid methane delivery system and liquid methane (LCH4) conditioning system. Facility checkout validation was conducted in preparation for a series of passive thermal control technology tests planned at SMiRF in FY10 using a flight-like propellant tank at simulated thermal environments from 140 to 350K. These tests will validate models and provide high quality data to support consideration of LCH4/LO2 propellant combination option for a lunar or planetary ascent stage.An infrastructure has been put in place which will support testing of large amounts of liquid methane at SMiRF. Extensive modifications were made to the test facility s existing liquid hydrogen system for compatibility with liquid methane. Also, a new liquid methane fluid conditioning system will enable liquid methane to be quickly densified (sub-cooled below normal boiling point) and to be quickly reheated to saturation conditions between 92 and 140 K. Fluid temperatures can be quickly adjusted to compress the overall test duration. A detailed trade study was conducted to determine an appropriate technique to liquid conditioning with regard to the SMiRF facility s existing infrastructure. In addition, a completely new roadable dewar has been procured for transportation and temporary storage of liquid methane. A new spherical, flight-representative tank has also been fabricated for integration into the vacuum chamber at SMiRF. The addition of this system to SMiRF marks the first time a large-scale liquid methane propellant test capability has been realized at Glenn.This work supports the Cryogenic Fluid Management Project being conducted under the auspices of the Exploration Technology Development Program, providing focused cryogenic fluid management technology efforts to support NASA s future robotic or human exploration missions.

Gas Generator Feedline Orifice Sizing Methodology: Effects of Unsteadiness and Non-Axisymmetric Flow

NASA Technical Reports Server (NTRS)

Rothermel, Jeffry; West, Jeffrey S.

2011-01-01

Engine LH2 and LO2 gas generator feed assemblies were modeled with computational fluid dynamics (CFD) methods at 100% rated power level, using on-center square- and round-edge orifices. The purpose of the orifices is to regulate the flow of fuel and oxidizer to the gas generator, enabling optimal power supply to the turbine and pump assemblies. The unsteady Reynolds-Averaged Navier-Stokes equations were solved on unstructured grids at second-order spatial and temporal accuracy. The LO2 model was validated against published experimental data and semi-empirical relationships for thin-plate orifices over a range of Reynolds numbers. Predictions for the LO2 square- and round-edge orifices precisely match experiment and semi-empirical formulas, despite complex feedline geometry whereby a portion of the flow from the engine main feedlines travels at a right-angle through a smaller-diameter pipe containing the orifice. Predictions for LH2 square- and round-edge orifice designs match experiment and semi-empirical formulas to varying degrees depending on the semi-empirical formula being evaluated. LO2 mass flow rate through the square-edge orifice is predicted to be 25 percent less than the flow rate budgeted in the original engine balance, which was subsequently modified. LH2 mass flow rate through the square-edge orifice is predicted to be 5 percent greater than the flow rate budgeted in the engine balance. Since CFD predictions for LO2 and LH2 square-edge orifice pressure loss coefficients, K, both agree with published data, the equation for K has been used to define a procedure for orifice sizing.

The Connection Between Local Icosahedral Order in Metallic Liquids and the Nucleation Behavior of Ordered Phases

NASA Technical Reports Server (NTRS)

Kelton, K. F.; Gangopadhyay, A. K.; Lee, G. W.; Hyers, R. W.; Rathz, T. J.; Rogers, J. R.; Robinson, M. B.; Schenk, T.; Simonet, V.

2003-01-01

Over fifty years ago, David Turnbull showed that the temperature of many metallic liquids could be decreased far below their equilibrium melting temperature before crystallization occurred. To explain those surprising results, Charles Frank hypothesized that the local structures of undercooled metallic liquids are different from those of crystal phases, containing a significant degree of icosahedral order that is incompatible with extended periodicity. Such structural differences must create a barrier to the formation crystal phases, explaining the observed undercooling behavior. If true, the nucleation from the liquid of phases with extended icosahedral order should be easier. Icosahedral order is often favored in small clusters, as observed recently in liquid-like clusters of pure Pb on the (111) surface of Si[3], for example. However, it has never been shown that an increasing preference for icosahedral phase formation can be directly linked with the development of icosahedral order in the undercooled liquid. Owing to the combination of very recent advances in levitation techniques and the availability of synchrotron x-ray and high flux neutron facilities, this is shown here.

The Connection Between Local Icosahedral Order in Metallic Liquids and the Nucleation of Ordered Phases

NASA Technical Reports Server (NTRS)

Curreri, Peter A. (Technical Monitor); Kelton, K. F.; Gangopadhyay, A.; Lee, G. W.; Hyers, R. W.; Rathz, R. J.; Rogers, J.; Schenk, T.; Simonet, V.; Holland-Moritz, D.

2003-01-01

Over fifty years ago, David Turnbull showed that the temperature of many metallic liquids could be decreased far below their equilibrium melting temperature before crystallization occurred. To explain those surprising results, Charles Frank hypothesized that the local structures of undercooled metallic liquids are different from those of crystal phases, containing a significant degree of icosahedral order that is incompatible with extended periodicity. Such structural differences must create a barrier to the formation crystal phases, explaining the observed undercooling behavior. If true, the nucleation from the liquid of phases with extended icosahedral order should be easier. Icosahedral order is often favored in small clusters, as observed recently in liquid-like clusters of pure Pb on the (111) surface of Si, for example. However, it has never been shown that an increasing preference for icosahedral phase formation can be directly linked with the development of icosahedral order in the undercooled liquid. Owing to the combination of very recent advances in levitation techniques and the availability of synchrotron x-ray and high flux neutron facilities, this is shown here.

The Connection Between Local Icosahedral Order in Metallic Liquids and the Nucleation of Ordered Phases

NASA Technical Reports Server (NTRS)

Kelton, K. F.; Gangopadhyay, A. K.; Lee, G. W.; Hyers, R. W.; Rathz, T. J.; Rogers, J. R.; Robinson, M. B.; Schenk, T.; Simonet, V.; Holland-Moritz, D.;

Auxiliary propulsion technology for advanced Earth-to-orbit vehicles

NASA Technical Reports Server (NTRS)

Schneider, Steven J.

1987-01-01

The payload which can be delivered to orbit by advanced Earth-to-Orbit vehicles is significantly increased by advanced subsystem technology. Any weight which can be saved by advanced subsystem design can be converted to payload at Main Engine Cut Off (MECO) given the same launch vehicle performance. The auxiliary propulsion subsystem and the impetus for the current hydrogen/oxygen technology program is examined. A review of the auxiliary propulsion requirements of advanced Earth-to-Orbit (ETO) vehicles and their proposed missions is given first. Then the performance benefits of hydrogen/oxygen auxiliary propulsion are illustrated using current shuttle data. The proposed auxiliary propulsion subsystem implementation includes liquid hydrogen/liquid oxygen (LH2/LO2) primary Reaction Control System (RCS) engines and gaseous hydrogen/gaseous oxygen (GH2/GO2) vernier RCS engines. A distribution system for the liquid cryogens to the engines is outlined. The possibility of providing one dual-phase engine that can operate on either liquid or gaseous propellants is being explored, as well as the simultaneous firing of redundant primary RCS thrusters to provide Orbital Maneuvering System (OMS) level impulse. Scavenging of propellants from integral main engine tankage is proposed to utilize main engine tank residuals and to combine launch vehicle and subsystem reserves.

Enhanced alpha-galactosidase expression in pseudomonas chlororaphis

USDA-ARS?s Scientific Manuscript database

Pseudomonas chlororaphis is a non-pathogenic bacterium useful for fermentative production of biopolymer (i.e., poly(hydroxyalkanoates); PHA) and biosurfactant (i.e., rhamnolipid; RhL). In order to enable P. chlororaphis to better fermentatively utilize the residual soy sugars in soy molasses – a lo...

Dynamic testbed demonstration of WFIRST coronagraph low order wavefront sensing and control (LOWFS/C)

NASA Astrophysics Data System (ADS)

Shi, Fang; Cady, Eric; Seo, Byoung-Joon; An, Xin; Balasubramanian, Kunjithapatham; Kern, Brian; Lam, Raymond; Marx, David; Moody, Dwight; Mejia Prada, Camilo; Patterson, Keith; Poberezhskiy, Ilya; Shields, Joel; Sidick, Erkin; Tang, Hong; Trauger, John; Truong, Tuan; White, Victor; Wilson, Daniel; Zhou, Hanying

2017-09-01

To maintain the required performance of WFIRST Coronagraph in a realistic space environment, a Low Order Wavefront Sensing and Control (LOWFS/C) subsystem is necessary. The LOWFS/C uses a Zernike wavefront sensor (ZWFS) with the phase shifting disk combined with the starlight rejecting occulting mask. For wavefront error corrections, WFIRST LOWFS/C uses a fast steering mirror (FSM) for line-of-sight (LoS) correction, a focusing mirror for focus drift correction, and one of the two deformable mirrors (DM) for other low order wavefront error (WFE) correction. As a part of technology development and demonstration for WFIRST Coronagraph, a dedicated Occulting Mask Coronagraph (OMC) testbed has been built and commissioned. With its configuration similar to the WFIRST flight coronagraph instrument the OMC testbed consists of two coronagraph modes, Shaped Pupil Coronagraph (SPC) and Hybrid Lyot Coronagraph (HLC), a low order wavefront sensor (LOWFS), and an optical telescope assembly (OTA) simulator which can generate realistic LoS drift and jitter as well as low order wavefront error that would be induced by the WFIRST telescope's vibration and thermal changes. In this paper, we will introduce the concept of WFIRST LOWFS/C, describe the OMC testbed, and present the testbed results of LOWFS sensor performance. We will also present our recent results from the dynamic coronagraph tests in which we have demonstrated of using LOWFS/C to maintain the coronagraph contrast with the presence of WFIRST-like line-of-sight and low order wavefront disturbances.

Theoretical evidence for a first-order liquid-liquid phase transition in gallium.

PubMed

Carvajal Jara, Diego Alejandro; Fontana Michelon, Mateus; Antonelli, Alex; de Koning, Maurice

2009-06-14

We report on theoretical results that lend support to recent experimental observations suggesting the existence of a first-order liquid-liquid phase transformation (LLPT) in gallium. Using molecular dynamics simulation based on a modified embedded-atom model, we observe a transition from a high-density to a low-density liquid in the supercooled regime. The first-order character of the transition is established through the detection of the release of latent heat and our findings suggest that the LLPT terminates in a critical point that is located in the tensile-strained domain of the metastable phase diagram.

Thermal performance evaluation of the Semco (liquid) solar collector

NASA Technical Reports Server (NTRS)

1979-01-01

Procedures used and results obtained during the evaluation test program on a flat plate collector which uses water as the working fluid are discussed. The absorber plate is copper tube soldered to copper fin coated with flat black paint. The glazing consists of two plates of Lo-Iron glass; the insulation is polyurethane foam. The collector weight is 242.5 pounds with overall external dimensions of approximately 48.8 in. x 120.8 in. x 4.1 in. The test program was conducted to obtain thermal performance data before and after 34 days of weather exposure test.

A Novel Liquid-Liquid Transition in Undercooled Ti-Zr-Ni Liquids

NASA Technical Reports Server (NTRS)

Lee, G. W.; Gangopadhyay, A. K.; Kelton, K. F.; Bradshaw, R. C.; Hyers, R. W.; Rathz, T. J.; Rogers, J. R.

2004-01-01

If crystallization can be avoided, liquids enter a metastable (undercooled) state below their equilibrium liquidus temperatures, T(sub l), finally 'freezing' into a glass below a characteristic temperature called the glass transition temperature, T(sub g). In rare cases, the undercooled liquid may undergo a liquid-liquid phase transition (liquid polymorphism) before entering the glassy state. This has been suggested from experimental studies of H2O and Si. Such phase transitions have been predicted in some stable liquids, ie. above T(sub l) at atmospheric pressure, for SiO2 and BeF2, but these have not been verified experimentally. They have been observed in liquids of P, Si and C, but only under high pressure. In this letter we present the first experimental evidence for a phase transition in a low viscosity metallic liquid that is driven by an approach to a constant entropy configuration state and correlated with a growing icosahedral order in the liquid. A maximum in the specific heat at constant pressure, similar to what is normally observed near T(sub g), is reported for undercooled liquids of quasicrystal-forming Ti-Zr-Ni alloys. A two-state excitation model that includes cooperativity by incorporating a temperature-dependent excitation energy, fits the specific heat data well, signaling a phase transition. An inflection in the liquid density with decreasing temperature instead of a discontinuity indicates that this is not a typical first order phase transition; it could be a weakly first order or higher order transition. While showing many similarities to a glass transition, this liquid-liquid phase transition occurs in a mobile liquid, making it novel.

Charge ordering in two-dimensional ionic liquids

NASA Astrophysics Data System (ADS)

Perera, Aurélien; Urbic, Tomaz

2018-04-01

The structural properties of model two-dimensional (2D) ionic liquids are examined, with a particular focus on the charge ordering process, with the use of computer simulation and integral equation theories. The influence of the logarithmic form of the Coulomb interaction, versus that of a 3D screened interaction form, is analysed. Charge order is found to hold and to be analogous for both interaction models, despite their very different form. The influence of charge ordering in the low density regime is discussed in relation to well known properties of 2D Coulomb fluids, such as the Kosterlitz-Thouless transition and criticality. The present study suggests the existence of a stable thermodynamic labile cluster phase, implying the existence of a liquid-liquid "transition" above the liquid-gas binodal. The liquid-gas and Kosterlitz-Thouless transitions would then take place inside the predicted cluster phase.

Estimation of zeta potential of electroosmotic flow in a microchannel using a reduced-order model.

PubMed

Park, H M; Hong, S M; Lee, J S

2007-10-01

A reduced-order model is derived for electroosmotic flow in a microchannel of nonuniform cross section using the Karhunen-Loève Galerkin (KLG) procedure. The resulting reduced-order model is shown to predict electroosmotic flows accurately with minimal consumption of computer time for a wide range of zeta potential zeta and dielectric constant epsilon. Using the reduced-order model, a practical method is devised to estimate zeta from the velocity measurements of the electroosmotic flow in the microchannel. The proposed method is found to estimate zeta with reasonable accuracy even with noisy velocity measurements.

Acoustically Forced Coaxial Hydrogen / Liquid Oxygen Jet Flames

DTIC Science & Technology

2016-05-15

serious problems in the development of liquid rocket engines. In order to understand and predict them, it is necessary to understand how representative...liquid rocket injector flames react to acoustic waves. In this study, a representative coaxial gaseous hydrogen / liquid oxygen (LOX) jet flame is...Combustion instabilities can pose serious problems in the development of liquid rocket engines. In order to under- stand and predict them, it is

Differential metabolome analysis of field-grown maize kernels in response to drought stress

USDA-ARS?s Scientific Manuscript database

Drought stress constrains maize kernel development and can exacerbate aflatoxin contamination. In order to identify drought responsive metabolites and explore pathways involved in kernel responses, a metabolomics analysis was conducted on kernels from a drought tolerant line, Lo964, and a sensitive ...

Studies of Nucleation and Growth, Specific Heat and Viscosity of Undercooled Melts of Quasicrystals and Polytetrehedral-Phase-Forming Alloys

NASA Technical Reports Server (NTRS)

2003-01-01

By investigating the properties of quasicrystals and quasicrystal-forming liquid alloys, we may determine the role of ordering of the liquid phase in the formation of quasicrystals, leading to a better fundamental understanding of both the quasicrystal and the liquid. A quasicrystal is solid characterized by a symmetric but non-periodic arrangement of atoms, usually in the form of an icosahedron (12 atoms, 20 triangular faces). It is theorized that the short-range order in liquids takes this same form. The degree of ordering depends on the temperature of the liquid, and affects many of the liquid s properties, including specific heat, viscosity, and electrical resistivity. The MSFC role in this project includes solidification studies, phase diagram determination, and thermophysical property measurements on the liquid quasicrystal-forming alloys, all by electrostatic levitation (ESL). The viscosity of liquid quasicrystal-forming alloys is measured by the oscillating drop method, both in the stable and undercooled liquid state. The specific heat of solid, undercooled liquid, and stable liquid are measured by the radiative cooling rate of the droplets.

Optical isotropy and iridescence in a smectic 'blue phase'.

PubMed

Yamamoto, Jun; Nishiyama, Isa; Inoue, Miyoshi; Yokoyama, Hiroshi

2005-09-22

When liquid crystal molecules are chiral, the twisted structure competes with spatially uniform liquid crystalline orders, resulting in a variety of modulated liquid crystal phases, such as the cholesteric blue phase, twist grain boundary and smectic blue phases. Here we report a liquid crystal smectic blue phase (SmBP(iso)), formed from a two-component mixture containing a chiral monomer and a 'twin' containing two repeat units of the first molecule connected by a linear hydrocarbon spacer. The phase exhibits the simultaneous presence of finite local-order parameters of helices and smectic layers, without any discontinuity on a mesoscopic length scale. The anomalous softening of elasticity due to a strong reduction in entropy caused by mixing the monomer and the twin permits the seamless coexistence of these two competing liquid crystal orders. The new phase spontaneously exhibits an optically isotropic but uniformly iridescent colour and automatically acquires spherical symmetry, so that the associated photonic band gap maintains the same symmetry despite the local liquid crystalline order. We expect a range of unusual optical transmission properties based on this three-dimensional isotropic structure, and complete tunability due to the intrinsic softness and responsiveness of the liquid crystalline order against external fields.

A new approach for selection of Oenococcus oeni strains in order to produce malolactic starters.

PubMed

Coucheney, Françoise; Desroche, Nicolas; Bou, Magali; Tourdot-Maréchal, Raphaëlle; Dulau, Laurent; Guzzo, Jean

2005-12-15

The lactic acid bacterium Oenococcus oeni, mainly responsible for malolactic fermentation (MLF), is used in new winery process as starter culture for direct inoculation. The difficulty to master MLF according to the wine led us to search a new approach to select effective O. oeni strains. Biochemical and molecular tests were performed in order to characterize three strains of O. oeni selected for malolactic starter elaboration. Malolactic and ATPase activities that appeared as a great interest in MLF were measured and the expression of a small heat shock protein Lo18 was evaluated by immunoblotting and real-time PCR. These results were correlated with the performances of strains in two red wines. Physiological and molecular characteristics of the three strains showed significant differences for the global malolactic activity on intact cell at pH 3.0 and at the level of induction of the small heat shock protein Lo18. These two parameters appeared of interest to evaluate in the ability of O. oeni strains to survive into wine after direct inoculation and to perform MLF. Indeed, a tested strain that presented the highest malolactic activity on intact cells at pH 3.0 and a high level of Lo18 induction showed a high growth rate and a high specific kinetic of malate consumption. The techniques used in this work carry out more quickly and more reliable than usual for the selection of effective strains intended for direct inoculation in wines.

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2012-02-16

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2012-08-10

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Predicting glass-to-glass and liquid-to-liquid phase transitions in supercooled water using classical nucleation theory

NASA Astrophysics Data System (ADS)

Tournier, Robert F.

2018-01-01

Glass-to-glass and liquid-to-liquid phase transitions are observed in bulk and confined water, with or without applied pressure. They result from the competition of two liquid phases separated by an enthalpy difference depending on temperature. The classical nucleation equation of these phases is completed by this quantity existing at all temperatures, a pressure contribution, and an enthalpy excess. This equation leads to two homogeneous nucleation temperatures in each liquid phase; the first one (Tn- below Tm) being the formation temperature of an "ordered" liquid phase and the second one corresponding to the overheating temperature (Tn+ above Tm). Thermodynamic properties, double glass transition temperatures, sharp enthalpy and volume changes are predicted in agreement with experimental results. The first-order transition line at TLL = 0.833 × Tm between fragile and strong liquids joins two critical points. Glass phase above Tg becomes "ordered" liquid phase disappearing at TLL at low pressure and at Tn+ = 1.302 × Tm at high pressure.

III-V on silicon micro-photonic circuits for frequency downconversion of RF signals

NASA Astrophysics Data System (ADS)

Roelkens, G.; Keyvaninia, S.; Tassaert, M.; Latkowski, S.; Bente, E.; Mariën, J.; Thomassen, L.; Baets, R.

2017-11-01

RF frequency downconverters are of key importance in communication satellites. Classically, this is implemented using an electronic mixer. In this paper we explore the use of photonic technology to realize the same functionality. The potential advantages of such an approach compared to the classical microwave solutions are that it is lighter weight, has lower power consumption and can be made smaller if photonic technology is used. An additional advantage is the fact that the optical local oscillator (LO) reference can easily be transported over longer distances than the equivalent LO signal in the microwave domain due to the large bandwidth and low loss and dispersion of optical fiber. Another big advantage is that one can envision the use of short pulse trains as the LO - starting off from a sinusoidal RF reference - in order to exploit subsampling. Subsampling avoids the need for high frequency LO references, which is especially valuable if a downconversion over several 10s of GHz is required. In this paper we present the operation principle of such a photonic frequency downconverter and describe the performance of the developed micro-photonic building blocks required for this functionality. These micro-photonic building blocks are implemented on a III-V semiconductor-on-silicon photonic platform. The components include a micro-photonic hybridly modelocked laser, a 30GHz electroabsorption modulator and an intermediate frequency (1.5GHz) photodetector.

Nanoimprint methods for the fabrication of macroscopic plasmonically active metal nanostructures

NASA Astrophysics Data System (ADS)

Nagel, Robin D.; Filser, Simon; Zhang, Tianyue; Manzi, Aurora; Schönleber, Konrad; Lindsly, James; Zimmermann, Josef; Maier, Thomas L.; Scarpa, Giuseppe; Krischer, Katharina; Lugli, Paolo

2017-02-01

In this article, we present a refined nanostructuring method, lift-off nanoimprint lithography (LO-NIL), which allows the deposition of high-quality metal nanostructures due to a bilayer resist process and compare it to nano-transfer printing (nTP), a purely additive metal printing technique. LO-NIL and nTP are used as accurate methods for the fabrication of ordered plasmonic metal nanostructure arrays on semiconducting substrates over large areas using the example of gold nanodisks on silicon. The possibility of feature size adjustment in LO-NIL during the fabrication process is especially useful for tuning plasmonic resonance peaks between the visible and the mid-infrared range as well as fine-tuning of these resonances. In UV-VIS-NIR spectroscopic measurements, a significant blueshift in the plasmonic resonance was found for nTP samples compared to the ones fabricated with the lift-off technique. It was concluded that this shift originates from a metal/substrate interface roughness resulting in a change in the dielectric properties of this layer. This finding was verified with finite difference time-domain simulations where a similar trend was found for a model with an assumed thin air gap in this interface. In cyclic voltammetry measurements under illumination, a reduced overpotential by almost 400 mV for CO2 reduction and hydrogen evolution was found for LO-NIL samples.

Impact of spherical nanoparticles on nematic order parameters

NASA Astrophysics Data System (ADS)

Kyrou, C.; Kralj, S.; Panagopoulou, M.; Raptis, Y.; Nounesis, G.; Lelidis, I.

2018-04-01

We study experimentally the impact of spherical nanoparticles on the orientational order parameters of a host nematic liquid crystal. We use spherical core-shell quantum dots that are surface functionalized to promote homeotropic anchoring on their interface with the liquid crystal host. We show experimentally that the orientational order may be strongly affected by the presence of spherical nanoparticles even at low concentrations. The orientational order of the composite system is probed by means of polarized micro-Raman spectroscopy and by optical birefringence measurements as function of temperature and concentration. Our data show that the orientational order depends on the concentration in a nonlinear way, and the existence of a crossover concentration χc≈0.004 pw . It separates two different regimes exhibiting pure-liquid crystal like (χ <χc ) and distorted-nematic ordering (χ >χc ), respectively. In the latter phase the degree of ordering is lower with respect to the pure-liquid crystal nematic phase.

Submillimeter-Wave Phasor Beam-Pattern Measurement Based on Two-Stage Heterodyne Mixing With Unitary Harmonic Difference

NASA Astrophysics Data System (ADS)

Hwang, Yuh-Jing; Rao, Ramprasad; Christensen, Rob; Chen, Ming-Tang; Chu, Tah-Hsiung

2007-06-01

A near-field phasor beam measurement system is developed for the characterization of heterodyne receiver optics at submillimeter-wave frequencies. The system synthesizes a pair of submillimeter-wave signals as the RF and local oscillator (LO) sources from common reference sources. The synthesized harmonic numbers of the RF and LO sources are arranged with difference by one, which makes this a new configuration with a unitary harmonic difference. The coherent RF and LO signal are down-converted by the receiver under test, then mixed with the microwave-frequency common reference signal to generate the second-order IF signal around 100 MHz for amplitude and phase comparison. The amplitude and phase fluctuation of the measurement system at 683 GHz is within +-0.2 dB and +-4deg in a 1-h period, respectively. The system dynamic range at 683 and 250 GHz can be as high as 43 and 47 dB, respectively. The system is then used to measure the receiver beam patterns at 683 and 250 GHz with different RF transmitting probe antennas.

Biofriendly nanocomposite containers with inhibition properties for the protection of metallic surfaces.

PubMed

Vakhitov, T R; Katnov, V E; Grishin, P V; Stepin, S N; Grigoriev, D O

2017-03-01

An attempt to combine two 'green' compounds in nanocomposite microcontainers in order to increase protection properties of waterborne acryl-styrene copolymer (ASC) coatings has been made. N -lauroylsarcosine (NLS) served as a corrosion inhibitor, and linseed oil (LO) as a carrier-forming component. LO is compatible with this copolymer and can impart to the coating self-healing properties. For the evaluation of the protective performance, three types of coatings were compared. In the first two, NLS was introduced in the coating formulation in the forms of free powder and micro-containers filled with LO, correspondingly. The last one was a standard ASC coating without inhibitor at all. Low-carbon steel substrates were coated by these formulations by spraying and subjected subsequently to the neutral salt spray test according to DIN ISO 9227. Results of these tests as well as the data obtained by electrochemical study suggest that such containers can be used for the improvement of adhesion of ASC-based coatings to the substrate and for the enhancement of their protective performance upon integrity damage, whereas the barrier properties of intact coatings were decreased.

Low phase noise microwave extraction from femtosecond laser by frequency conversion pair and IF-domain processing.

PubMed

Dai, Yitang; Cen, Qizhuang; Wang, Lei; Zhou, Yue; Yin, Feifei; Dai, Jian; Li, Jianqiang; Xu, Kun

2015-12-14

Extraction of a microwave component from a low-time-jitter femtosecond pulse train has been attractive for current generation of spectrally pure microwave. In order to avoid the transfer from the optical amplitude noise to microwave phase noise (AM-PM), we propose to down-convert the target component to intermediate frequency (IF) before the opto-electronic conversion. Due to the much lower carrier frequency, the AM-PM is greatly suppressed. The target is then recovered by up-conversion with the same microwave local oscillation (LO). As long as the time delay of the second LO matches that of the IF carrier, the phase noise of the LO shows no impact on the extraction process. The residual noise of the proposed extraction is analyzed in theory, which is also experimentally demonstrated as averagely around -155 dBc/Hz under offset frequency larger than 1 kHz when 10-GHz tone is extracted from a home-made femtosecond fiber laser. Large tunable extraction from 1 GHz to 10 GHz is also reported.

3D Visualization of Urban Area Using Lidar Technology and CityGML

NASA Astrophysics Data System (ADS)

Popovic, Dragana; Govedarica, Miro; Jovanovic, Dusan; Radulovic, Aleksandra; Simeunovic, Vlado

2017-12-01

3D models of urban areas have found use in modern world such as navigation, cartography, urban planning visualization, construction, tourism and even in new applications of mobile navigations. With the advancement of technology there are much better solutions for mapping earth’s surface and spatial objects. 3D city model enables exploration, analysis, management tasks and presentation of a city. Urban areas consist of terrain surfaces, buildings, vegetation and other parts of city infrastructure such as city furniture. Nowadays there are a lot of different methods for collecting, processing and publishing 3D models of area of interest. LIDAR technology is one of the most effective methods for collecting data due the large amount data that can be obtained with high density and geometrical accuracy. CityGML is open standard data model for storing alphanumeric and geometry attributes of city. There are 5 levels of display (LoD0, LoD1, LoD2, LoD3, LoD4). In this study, main aim is to represent part of urban area of Novi Sad using LIDAR technology, for data collecting, and different methods for extraction of information’s using CityGML as a standard for 3D representation. By using series of programs, it is possible to process collected data, transform it to CityGML and store it in spatial database. Final product is CityGML 3D model which can display textures and colours in order to give a better insight of the cities. This paper shows results of the first three levels of display. They consist of digital terrain model and buildings with differentiated rooftops and differentiated boundary surfaces. Complete model gives us a realistic view of 3D objects.

Risk factors and study designs used in research of youths' suicide behaviour-an epidemiological discussion with focus on level of evidence.

PubMed

Christiansen, Erik; Larsen, Kim Juul; Agerbo, Esben; Bilenberg, Niels; Stenager, Elsebeth

2014-11-01

Abstract Introduction: Many different epidemiology study designs have been used to analyse risk factors for suicide behaviour. The purpose of this study was to obtain an insight into the current study design used in research on youths' risk factors for suicide behaviour and to rank the studies according to level of evidence (LoE). We searched PubMed and psycINFO in order to identify relevant individual studies. We included 36 studies of children and youth on suicidal behaviour and ideation-many rank low on LoE. For suicide, cohort design was often used, and mental illness (depression, substance abuse and severity of mental illness) was the most common risk factor. Cohort studies are ranked 2b, which is high according to LoE. For suicide attempts, survey was often used, and psychopathology, substance abuse and being exposed to suicidal behaviour were the most common risk factors. For suicidal ideation, survey was the only design used, and substance abuse and psychopathology the most common risk factors. Surveys are ranked 4, which are low according to LoE. Many risk factors were broad and unspecific, and standard definitions of outcome and exposure were rarely used. A good study of risk factors for suicidal behaviour would need a high LoE, as a high-powered longitudinal epidemiological study (cohort or case-control) of very specific risk factors. The factors would have high prevention potential, compared with more broad and unspecific risk factors, to which many people are exposed. We would recommend a cohort design (in high-risk populations) or a case-control design to identify risk factors, using clinical and/or register data instead of self-reported information, reporting adjusted estimates and using standard definition of suicidal outcome and risk factors.

Emotion, Engagement, and Case Studies

ERIC Educational Resources Information Center

Herreid, Clyde Freeman; Terry, David R.; Lemons, Paula; Armstrong, Norris; Brickman, Peggy; Ribbens, Eric

2014-01-01

Three college faculty taught large general biology classes using case studies and personal response systems (clickers). Each instructor taught the same eight cases in two different sections, except the questions within the cases differed. In one section the questions were lower order (LO) factual inquiries, and in the other they were largely…

77 FR 29438 - Self-Regulatory Organizations; EDGX Exchange, Inc.; Notice of Filing and Immediate Effectiveness...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-05-17

... ``added liquidity'' to ``removed liquidity'' ratio of at least 70% where added flags are defined as B, HA..., Flag N is yielded when an order removes liquidity from the EDGX book in Tapes B or C securities. In... Members, the Exchange proposes to amend Flag N so that it only applies to orders that remove liquidity...

Nonlinear breakup of liquid sheets

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jazayeri, S.A.; Li, X.

1997-07-01

Sprays formed from the disintegration of liquid sheets have extensive practical applications, ranging from chemical and pharmaceutical processes to power generation and propulsion systems. A knowledge of the liquid sheet breakup process is essential to the understanding of fundamental mechanism of liquid atomization and spray formation processes. The breakup of liquid sheets has been investigated in terms of hydrodynamic stability via linear analysis by Squire, Hagerty and Shea, Li, etc. nonlinear effect has been studied by Clark and Dombrowski up to the second order, and by Rangel and Sirignano through numerical simulation employing vortex discretization method. As shown by Taubmore » for the breakup of circular liquid jets, the closer to the breakup region, the higher the order of nonlinear analysis has to be for adequate description of the breakup behavior. As pointed out by Bogy, a nonlinear analysis up to the third order is generally sufficient to account for the inherent nonlinear nature of the breakup process. Therefore, a third-order nonlinear analysis has been carried out in this study to investigate the process of liquid sheet disruption preceding the spray formation.« less

Hugoniots of aerogels involving carbon and resorcinol formaldehyde

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hrubesh, L H; Ree, F H; Schmidt, R D

1999-06-24

Recently, a first-order phase transition is predicted in liquid carbon using atomistic simulation and Brenner's bond order potential. There are also experimental data suggesting a possibility for a first-order phase transition. In light of this, a thermochemical equilibrium code (CHEQ) is used to provide guidance to experiments to find a liquid-liquid phase change in carbon foam and carbon-rich aerogel, resorcinol formaldehyde. Isotherms and Hugoniots were computed based on the previous analysis by van Thiel and Ree. The present calculations predict the liquid-liquid-graphite triple point to be at 5000 K and 5.2 GPa and its critical point to be at 6000more » K and 8.8 GPa. The present Hugoniot calculations suggest that the liquid-liquid phase transition may be detected by performing a shock experiment with initial density of approximately 0.15 gm/cm{sup 3}.« less

Inclusive prompt photon production in electron-nucleus scattering at small x

NASA Astrophysics Data System (ADS)

Roy, Kaushik; Venugopalan, Raju

2018-05-01

We compute the differential cross-section for inclusive prompt photon production in deeply inelastic scattering (DIS) of electrons on nuclei at small x in the framework of the Color Glass Condensate (CGC) effective theory. The leading order (LO) computation in this framework resums leading logarithms in x as well as power corrections to all orders in Q s, A 2 / Q 2, where Q s, A ( x) is the nuclear saturation scale. This LO result is proportional to universal dipole and quadrupole Wilson line correlators in the nucleus. In the soft photon limit, the Low-Burnett-Kroll theorem allows us to recover existing results on inclusive DIS dijet production. The k ⊥ and collinearly factorized expressions for prompt photon production in DIS are also recovered in a leading twist approximation to our result. In the latter case, our result corresponds to the dominant next-to-leading order (NLO) perturbative QCD contribution at small x. We next discuss the computation of the NLO corrections to inclusive prompt photon production in the CGC framework. In particular, we emphasize the advantages for higher order computations in inclusive photon production, and for fully inclusive DIS, arising from the simple momentum space structure of the dressed quark and gluon "shock wave" propagators in the "wrong" light cone gauge A - = 0 for a nucleus moving with P N + → ∞.

Using Aerogel-Based Insulation Material To Prevent Foam Loss on the Liquid-Hydrogen Intertank

NASA Technical Reports Server (NTRS)

2008-01-01

Uninsulated areas on cryogenic propellant tanks and feedlines cause moisture in the air to condense or ice to form. Flange joints, bracket supports, expansion bellows, and other cavities are uninsulated by design. These areas cannot be sealed because conventional thermal insulation materials would restrict mechanical articulations. Aerogel-based thermal insulation systems are able to seal critical locations such as the liquid-oxygen (LO2) feedline bellows. A new thermal insulation system was also necessary between the intertank wall, flange, and the liquid-hydrogen (LH2) tank dome, where there is a cavity (or crevice) with an exposed 20-K surface. When nitrogen gas is used for purging within the intertank volume, it condenses on this cold surface. Some solid nitrogen may also form on the colder side of the crevice. Voids or discontinuities within the foam can pressurize and cause areas of foam to weaken and break off, reducing thermal efficiency and creating potentially dangerous debris. To prevent this foam loss, we developed a thermal insulation system using bulk-fill aerogel material and demonstrated it with a one-tenth-scale model of the LH2 intertank flange area

76 FR 30417 - Self-Regulatory Organizations; NYSE Arca, Inc.; Notice of Filing and Immediate Effectiveness of...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-05-25

... Change Amending Rule 7.31(h)(5) To Reduce the Minimum Order Entry Size of a Mid-Point Passive Liquidity... order entry size of a Mid-Point Passive Liquidity Order (``MPL Order'') from 100 shares to one share...

Short and Medium-Range Order in Liquid Ternary Al80Co10Ni10, Al72.5Co14.5Ni13, and Al65Co17.5Ni17.5 Alloys

NASA Astrophysics Data System (ADS)

Roik, Oleksandr S.; Samsonnikov, Oleksiy; Kazimirov, Volodymyr; Sokolskii, Volodymyr

2010-01-01

A local short-to-intermediate range order of liquid Al80Co10Ni10, Al72.5Co14.5Ni13, and Al65Co17.5Ni17.5 alloys was examined by X-ray diffraction and the reverse Monte Carlo modelling. The comprehensive analysis of three-dimensional models of the liquid ternary alloys was performed by means of the Voronoi-Delaunay method. The existence of a prepeak on the S(Q) function of the liquid alloys is caused by medium range ordering of 3d-transition metal atoms in dense-packed polytetrahedral clusters at temperatures close to the liquidus. The non-crystalline clusters, represented by aggregates of pentagons that consist of good tetrahedra, and chemical short-range order lead to the formation of the medium range order in the liquid binary Al-Ni, Al-Co and ternary Al-Ni-Co alloys.

Abiotic ligation of DNA oligomers templated by their liquid crystal ordering

NASA Astrophysics Data System (ADS)

Fraccia, Tommaso P.; Smith, Gregory P.; Zanchetta, Giuliano; Paraboschi, Elvezia; Yi, Yougwooo; Walba, David M.; Dieci, Giorgio; Clark, Noel A.; Bellini, Tommaso

2015-03-01

It has been observed that concentrated solutions of short DNA oligomers develop liquid crystal ordering as the result of a hierarchically structured supramolecular self-assembly. In mixtures of oligomers with various degree of complementarity, liquid crystal microdomains are formed via the selective aggregation of those oligomers that have a sufficient degree of duplexing and propensity for physical polymerization. Here we show that such domains act as fluid and permeable microreactors in which the order-stabilized molecular contacts between duplex terminals serve as physical templates for their chemical ligation. In the presence of abiotic condensing agents, liquid crystal ordering markedly enhances ligation efficacy, thereby enhancing its own phase stability. The coupling between order-templated ligation and selectivity provided by supramolecular ordering enables an autocatalytic cycle favouring the growth of DNA chains, up to biologically relevant lengths, from few-base long oligomers. This finding suggests a novel scenario for the abiotic origin of nucleic acids.

75 FR 69507 - Self-Regulatory Organizations; National Stock Exchange, Inc.; Notice of Filing and Immediate...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-11-12

... and above that add liquidity in the Automatic Execution mode of order interaction (``AutoEx'').\\3\\ \\3... displayed orders in Tape A and C securities priced one dollar and above that add liquidity in AutoEx, the... that add liquidity in AutoEx if such ETP Holder's Liquidity Adding ADV is less than 20 basis points of...

Exceptionally Slow Movement of Gold Nanoparticles at a Solid/Liquid Interface Investigated by Scanning Transmission Electron Microscopy.

PubMed

Verch, Andreas; Pfaff, Marina; de Jonge, Niels

2015-06-30

Gold nanoparticles were observed to move at a liquid/solid interface 3 orders of magnitude slower than expected for the movement in a bulk liquid by Brownian motion. The nanoscale movement was studied with scanning transmission electron microscopy (STEM) using a liquid enclosure consisting of microchips with silicon nitride windows. The experiments involved a variation of the electron dose, the coating of the nanoparticles, the surface charge of the enclosing membrane, the viscosity, and the liquid thickness. The observed slow movement was not a result of hydrodynamic hindrance near a wall but instead explained by the presence of a layer of ordered liquid exhibiting a viscosity 5 orders of magnitude larger than a bulk liquid. The increased viscosity presumably led to a dramatic slowdown of the movement. The layer was formed as a result of the surface charge of the silicon nitride windows. The exceptionally slow motion is a crucial aspect of electron microscopy of specimens in liquid, enabling a direct observation of the movement and agglomeration of nanoscale objects in liquid.

Partial breaking of the Coulombic ordering of ionic liquids confined in carbon nanopores

PubMed Central

Futamura, Ryusuke; Iiyama, Taku; Takasaki, Yuma; Gogotsi, Yury; Biggs, Mark J.; Salanne, Mathieu; Ségalini, Julie; Simon, Patrice; Kaneko, Katsumi

2017-01-01

Ionic liquids are composed of equal quantities of positive and negative ions. In the bulk, electrical neutrality occurs in these liquids due to Coulombic ordering, in which ion shells of alternating charge form around a central ion. Their structure under confinement is far less well understood. This hinders the widespread application of ionic liquids in technological applications. Here we use scattering experiments to resolve the structure of the widely used ionic liquid (EMI-TFSI) when it is confined inside nanoporous carbons. We show that Coulombic ordering reduces when the pores can only accommodate a single layer of ions. Instead, equally-charged ion pairs are formed due to the induction of an electric potential of opposite sign in the carbon pore walls. This non-Coulombic ordering is further enhanced in the presence of an applied external electric potential. This finding opens the door for the design of better materials for electrochemical applications. PMID:28920938

Surface induced smectic order in ionic liquids - an X-ray reflectivity study of [C22C1im]+[NTf2].

PubMed

Mars, Julian; Hou, Binyang; Weiss, Henning; Li, Hailong; Konovalov, Oleg; Festersen, Sven; Murphy, Bridget M; Rütt, Uta; Bier, Markus; Mezger, Markus

2017-10-11

Surface induced smectic order was found for the ionic liquid 1-methyl-3-docosylimidazolium bis(trifluoromethlysulfonyl)imide by X-ray reflectivity and grazing incidence scattering experiments. Near the free liquid surface, an ordered structure of alternating layers composed of polar and non-polar moieties is observed. This leads to an oscillatory interfacial profile perpendicular to the liquid surface with a periodicity of 3.7 nm. Small angle X-ray scattering and polarized light microscopy measurements suggest that the observed surface structure is related to fluctuations into a metastable liquid crystalline SmA 2 phase that was found by supercooling the bulk liquid. The observed surface ordering persists up to 157 °C, i.e. more than 88 K above the bulk melting temperature of 68.1 °C. Close to the bulk melting point, we find a thickness of the ordered layer of L = 30 nm. The dependency of L(τ) = Λ ln(τ/τ 1 ) vs. reduced temperature τ follows a logarithmic growth law. In agreement with theory, the pre-factor Λ is governed by the correlation length of the isotropic bulk phase.

Hadronic Leading Order Contribution to the Muon g-2

NASA Astrophysics Data System (ADS)

Nomura, Daisuke

2018-05-01

We calculate the Standard Model (SM) prediction for the muon anomalous magnetic moment. By using the latest experimental data for e+e- → hadrons as input to dispersive integrals, we obtain the values of the leading order (LO) and the next-to-leading-order (NLO) hadronic vacuum polarisation contributions as ahad, LO VPμ = (693:27 ± 2:46) × 10-10 and ahad, NLO VP μ = (_9.82 ± 0:04) × 1010-10, respectively. When combined with other contributions to the SM prediction, we obtain aμ(SM) = (11659182:05 ± 3.56) × 10-10; which is deviated from the experimental value by Δaμ(exp) _ aμ(SM) = (27.05 ± 7.26) × 10-10. This means that there is a 3.7 σ discrepancy between the experimental value and the SM prediction. We also discuss another closely related quantity, the running QED coupling at the Z-pole, α(M2 Z). By using the same e+e- → hadrons data as input, our result for the 5-flavour quark contribution to the running QED coupling at the Z pole is Δ(5)had(M2 Z) = (276.11 ± 1.11) × 10-4, from which we obtain Δ(M2 Z) = 128.946 ± 0.015.

Phenomenological model and phase behavior of saturated and unsaturated lipids and cholesterol.

PubMed

Putzel, G Garbès; Schick, M

2008-11-15

We present a phenomenological theory for the phase behavior of ternary mixtures of cholesterol and saturated and unsaturated lipids, one that describes both liquid and gel phases. It leads to the following description of the mechanism of the phase behavior: In a binary system of the lipids, phase separation occurs when the saturated chains are well ordered, as in the gel phase, simply due to packing effects. In the liquid phase, the saturated ones are not sufficiently well ordered for separation to occur. The addition of cholesterol, however, increases the saturated lipid order to the point that phase separation is once again favorable. Our theory addresses this last mechanism-the means by which cholesterol-mediated ordering of membrane lipids leads to liquid-liquid immiscibility. It produces, for the system above the main chain transition of the saturated lipid, phase diagrams in which there can be liquid-liquid phase separation in the ternary system but not in any of the binary ones, while below that temperature it yields the more common phase diagram in which a gel phase, rich in saturated lipid, appears in addition to the two liquid phases.

A review of candidate multilayer insulation systems for potential use on wet-launched LH2 tankage for the Space Exploration Initiative lunar missions

NASA Technical Reports Server (NTRS)

Knoll, Richard H.; Stochl, Robert J.; Sanabria, Rafael

1991-01-01

The storage of cryogenic propellants such as liquid hydrogen (LH2) and liquid oxygen (LO2) for the future Space Exploration Initiative (SEI) will require lightweight, high performance thermal protection systems (TPSs). For the near-term lunar missions, the major weight element for most of the TPSs will be multilayer insulation (MLI) and/or the special structures/systems required to accommodate the MLI. Methods of applying MLI to LH2 tankage to avoid condensation or freezing of condensible gases such as nitrogen or oxygen while in the atmosphere are discussed. Because relatively thick layers of MLI will be required for storage times of a month or more, the transient performance from ground-hold to space-hold of the systems will become important in optimizing the TPSs for many of the missions. The ground-hold performance of several candidate systems are given as well as a qualitative assessment of the transient performance effects.

Feasibility Study of Laboratory Simulation of Single-Stage-to-Orbit Vehicle Base Heating

NASA Technical Reports Server (NTRS)

Park, Chung Sik; Sharma, Surendra; Edwards, Thomas A. (Technical Monitor)

1995-01-01

The feasibility of simulating in a laboratory the heating environment of the base region of the proposed reusable single-stage-to-orbit vehicle during its ascent is examined. The propellant is assumed to consist of hydrocarbon (RP1), liquid hydrogen (LH2), and liquid oxygen (LO2), which produces CO and H2 as the main combustible components of the exhaust effluent. Since afterburning in the recirculating region can dictate the temperature of the base flowfield and ensuing heating phenomena, laboratory simulation focuses on the thermochemistry of the afterburning. By extrapolating the Saturn V flight data, the Damkohler number, in the base region with afterburning for SSTO vehicle, is estimated to be between 30 and 140. It is shown that a flow with a Damkohler number of 1.8 to 25 can be produced in an impulse ground test facility. Even with such a reduced Damkohler number, the experiment can adequately reproduce the main features of the flight environment.

A review of candidate multilayer insulation systems for potential use on wet-launched LH2 tankage for the space exploration initiative lunar missions

NASA Technical Reports Server (NTRS)

Knoll, Richard H.; Stochl, Robert J.; Sanabria, Rafael

1991-01-01

The storage of cryogenic propellants such as liquid hydrogen (LH2) and liquid oxygen (LO2) for the future Space Exploration Initiative (SEI) will require lightweight, high performance thermal protection systems (TPS's). For the near-term lunar missions, the major weight element for most of the TPS's will be multilayer insulation (MLI) and/or the special structures/systems required to accommodate the MLI. Methods of applying MLI to LH2 tankage to avoid condensation or freezing of condensible gases such as nitrogen or oxygen while in the atmosphere are discussed. Because relatively thick layers of MLI will be required for storage times of a month or more, the transient performance from ground-hold to space-hold of the systems will become important in optimizing the TPS's for many of the missions. The ground-hold performance of several candidate systems are given as well as a qualitative assessment of the transient performance effects.

W production at large transverse momentum at the CERN Large Hadron Collider.

PubMed

Gonsalves, Richard J; Kidonakis, Nikolaos; Sabio Vera, Agustín

2005-11-25

We study the production of W bosons at large transverse momentum in pp collisions at the CERN Large Hadron Collider. We calculate the complete next-to-leading order (NLO) corrections to the differential cross section. We find that the NLO corrections provide a large increase to the cross section but, surprisingly, do not reduce the scale dependence relative to leading order (LO). We also calculate next-to-next-to-leading-order (NNLO) soft-gluon corrections and find that, although they are small, they significantly reduce the scale dependence thus providing a more stable result.

Simulated Rainfall-Driven Dissolution of TNT, Tritonal, Comp B and Octol Particles

DTIC Science & Technology

2009-01-01

Comp B a b s t r a c t Live-fire military training can deposit millimeter- sized particles of high explosives (HE) on surface soils when rounds do not...might dissolve under the action of rainfall and to use the data to verify a model that predicts HE dissolution as a function of particle size , particle...Detonations scatter HE particles broadly over surface soils. High-order detonations scatter lm- size HE particles and low-order (LO) detonations scatter

Prenucleation Induced by Crystalline Substrates

NASA Astrophysics Data System (ADS)

Men, H.; Fan, Z.

2018-04-01

Prenucleation refers to the phenomenon of atomic ordering in the liquid adjacent to the substrate/liquid interface at temperatures above the liquidus. In this paper, we have systematically investigated and holistically quantified the prenucleation phenomenon as a function of temperature and the lattice misfit between the substrate and the solid, using molecular dynamics (MD) simulations. Our results have confirmed that at temperatures above the liquidus, the atoms in the liquid at the interface may exhibit pronounced atomic ordering, manifested by atomic layering normal to the interface, in-plane atomic ordering parallel to the interface, and the formation of a 2-dimensional (2D) ordered structure (a few atomic layers in thickness) on the substrate surface. Holistic quantification of such atomic ordering at the interface has revealed that the atomic layering is independent of lattice misfit and is only slightly enhanced by reducing temperature while both in-plane atomic ordering and the formation of the 2D ordered structure are significantly enhanced by reducing the lattice misfit and/or temperature. This substrate-induced atomic ordering in the liquid may have a significant influence on the subsequent heterogeneous nucleation process.

Conjugated fatty acids and methane production by rumen microbes when incubated with linseed oil alone or mixed with fish oil and/or malate.

PubMed

Li, Xiang Z; Gao, Qing S; Yan, Chang G; Choi, Seong H; Shin, Jong S; Song, Man K

2015-08-01

We hypothesized that manipulating metabolism with fish oil and malate as a hydrogen acceptor would affect the biohydrogenation process of α-linolenic acid by rumen microbes. This study was to examine the effect of fish oil and/or malate on the production of conjugated fatty acids and methane (CH4 ) by rumen microbes when incubated with linseed oil. Linseed oil (LO), LO with fish oil (LO-FO), LO with malate (LO-MA), or LO with fish oil and malate (LO-FO-MA) was added to diluted rumen fluid, respectively. The LO-MA and LO-FO-MA increased pH and propionate concentration compared to the other treatments. LO-MA and LO-FO-MA reduced CH4 production compared to LO. LO-MA and LO-FO-MA increased the contents of c9,t11-conjugated linoleic acid (CLA) and c9,t11,c15-conjugated linolenic acid (CLnA) compared to LO. The content of malate was rapidly reduced while that of lactate was reduced in LO-MA and LO-FO-MA from 3 h incubation time. The fold change of the quantity of methanogen related to total bacteria was decreased at both 3 h and 6 h incubation times in all treatments compared to the control. Overall data indicate that supplementation of combined malate and/or fish oil when incubated with linseed oil, could depress methane generation and increase production of propionate, CLA and CLnA under the conditions of the current in vitro study. © 2015 Japanese Society of Animal Science.

75 FR 25013 - Self-Regulatory Organizations; NYSE Arca, Inc.; Notice of Filing and Immediate Effectiveness of...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-05-06

... Change Amending Its Mid- Point Passive Liquidity Order April 29, 2010. Pursuant to Section 19(b)(1) \\1...-Point Passive Liquidity Order (``MPL Order''). The text of the proposed rule change is available on the...

Chiral Three-Nucleon Interactions in Light Nuclei, Neutron-α Scattering, and Neutron Matter

DOE PAGES

Lynn, J. E.; Tews, I.; Carlson, Joseph Allen; ...

2016-02-09

Here we present quantum Monte Carlo calculations of light nuclei, neutron- scattering, and neutron matter using local two- and three-nucleon (3N) interactions derived from chiral e effective fi eld theory up to next-to-next-to-leading order (N 2LO). The two undetermined 3N low-energy couplings are fi t to the 4He binding energy and, for the first time, to the spin-orbit splitting in the neutron- P-wave phase shifts. Furthermore, we investigate different choices of local 3N-operator structures and find that chiral interactions at N 2LO are able to simultaneously reproduce the properties of A = 3; 4; 5 systems and of neutron matter,more » in contrast to commonly used phenomenological 3N interactions.« less

Chiral Three-Nucleon Interactions in Light Nuclei, Neutron-α Scattering, and Neutron Matter

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lynn, J. E.; Tews, I.; Carlson, Joseph Allen

Here we present quantum Monte Carlo calculations of light nuclei, neutron- scattering, and neutron matter using local two- and three-nucleon (3N) interactions derived from chiral e effective fi eld theory up to next-to-next-to-leading order (N 2LO). The two undetermined 3N low-energy couplings are fi t to the 4He binding energy and, for the first time, to the spin-orbit splitting in the neutron- P-wave phase shifts. Furthermore, we investigate different choices of local 3N-operator structures and find that chiral interactions at N 2LO are able to simultaneously reproduce the properties of A = 3; 4; 5 systems and of neutron matter,more » in contrast to commonly used phenomenological 3N interactions.« less

Estradiol agonists inhibit human LoVo colorectal-cancer cell proliferation and migration through p53.

PubMed

Hsu, Hsi-Hsien; Kuo, Wei-Wen; Ju, Da-Tong; Yeh, Yu-Lan; Tu, Chuan-Chou; Tsai, Ying-Lan; Shen, Chia-Yao; Chang, Sheng-Huang; Chung, Li-Chin; Huang, Chih-Yang

2014-11-28

To investigate the effects of 17β-estradiol via estrogen receptors (ER) or direct administration of ER agonists on human colorectal cancer. LoVo cells were established from the Bioresource Collection and Research Center and cultured in phenol red-free DMEM (Sigma, United States). To investigate the effects of E2 and/or ER selective agonists on cellular proliferation, LoVo colorectal cells were treated with E2 or ER-selective agonists for 24 h and 48 h and subjected to the MTT (Sigma) assay to find the concentration. And investigate the effects of E2 and/or ER selective agonists on cell used western immunoblotting to find out the diversification of signaling pathways. In order to observe motility and migration the wound healing assay and a transwell chamber (Neuro Probe) plate were tased. For a quantitative measure, we counted the number of migrating cells to the wound area post-wounding for 24 h. We further examined the cellular migration-regulating factors urokinase-type plasminogen activator (u-PA), tissue-type plasminogen activator (t-PA) and matrix metalloproteinase (MMP)-9 in human LoVo cells so gelatin zymography that we used and gelatinolytic activity was visualized by Coomassie blue staining. And these results are presented as means ± SE, and statistical comparisons were made using Student's t-test. The structure was first compared with E2 and ER agonists. We then treated the LoVo cells with E2 and ER agonists (10(-8) mol/L) for 24 h and 48 h and subsequently measured the cell viability using MTT assay. Our results showed that treatment with 17β-estradiol and/or ER agonists in human LoVo colorectal cancer cells activated p53 and then up-regulated p21 and p27 protein levels, subsequently inhibiting the downstream target gene, cyclin D1, which regulates cell proliferation. Taken together, our findings demonstrate the anti-tumorigenesis effects of 17β-estradiol and/or ER agonists and suggest that these compounds may prove to be a potential alternative therapy in the treatment of human colorectal cancer. These results demonstrate that 17β-estradiol and/or ER agonists downregulate migration-related proteins through the p53 signaling pathway in human LoVo colorectal cancer cells. These findings suggest that p53 plays a critical role in the 17β-estradiol and/or ER agonist-mediated protective activity against colorectal cancer progression. In addition, 17β-estradiol and/or ER agonists dramatically inhibited cell migration and reduced the expression of u-PA, t-PA and MMP-9 as well as MMP-2/9 activity in LoVo cells, which regulate cell metastasis. Moreover, we observed that pretreatment with a p53 inhibitor significantly blocked the anti-migration effects of E2 and/or ER agonists on LoVo cells. That E2 and/or ER agonists may impair LoVo cell migration by modulating migration-related factors via the p53 tumor suppressor gene. Direct ER treatment may prove to be an attractive alternative therapy in the treatment of human colorectal tumors in the future.

Anomalous Price Impact and the Critical Nature of Liquidity in Financial Markets

NASA Astrophysics Data System (ADS)

Tóth, B.; Lempérière, Y.; Deremble, C.; de Lataillade, J.; Kockelkoren, J.; Bouchaud, J.-P.

2011-10-01

We propose a dynamical theory of market liquidity that predicts that the average supply/demand profile is V shaped and vanishes around the current price. This result is generic, and only relies on mild assumptions about the order flow and on the fact that prices are, to a first approximation, diffusive. This naturally accounts for two striking stylized facts: First, large metaorders have to be fragmented in order to be digested by the liquidity funnel, which leads to a long memory in the sign of the order flow. Second, the anomalously small local liquidity induces a breakdown of the linear response and a diverging impact of small orders, explaining the “square-root” impact law, for which we provide additional empirical support. Finally, we test our arguments quantitatively using a numerical model of order flow based on the same minimal ingredients.

Atomic study on the ordered structure in Al melts induced by liquid/substrate interface with Ti solute

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, H. L.; Han, Y. F., E-mail: yfhan@sjtu.edu.cn, E-mail: bdsun@sjtu.edu.cn; Zhou, W.

2015-01-26

Atomic ordering in Al melts induced by liquid/substrate interface with Ti solute was investigated by ab initio molecular dynamics simulations and in-situ synchrotron X-ray diffraction. It is predicted that deformed nanoscale ordering Al layers with a rhombohedral-centered hexagonal structure (R3{sup ¯}m space group) instead of the intrinsic fcc structure (Fm3{sup ¯}m space group) form on substrate at temperature above Al liquids. With Al atoms stacking away from the interface, the ordering structure reaches a critical thickness, which inhibits the consecutive stacking of Al atoms on substrates. The locally stacking reconstruction induced by Ti atom relieves the accumulated elastic strain energymore » in ordered Al layers, facilitating fully heterogeneous nucleation on substrate beyond the deformed ordering Al layer around the melting point. The roles of liquid/substrate interface with Ti solute in the physical behavior of heterogeneous nucleation on substrate were discussed.« less

Phototropic liquid crystal materials containing naphthopyran dopants

NASA Astrophysics Data System (ADS)

Rumi, Mariacristina; Cazzell, Seth; Kosa, Tamas; Sukhomlinova, Ludmila; Taheri, Bahman; Bunning, Timothy; White, Timothy

2015-03-01

Dopant molecules dispersed in a liquid crystalline material usually affects the order of the system and the transition temperature between various phases. If the dopants undergo photoisomerization between conformers with different shapes, the interactions with the liquid crystal molecules can be different for the material in the dark and during exposure to light of appropriate wavelength. This can be used to achieve isothermal photoinduced phase transitions (phototropism). With proper selection of materials components, both order-to-disorder and disorder-to-order photoinduced transition have been demonstrated. Isothermal order-increasing transitions have been observed recently using naphthopyran derivatives as dopants. We are investigating the changes in order parameter and transition temperature of liquid crystal mixtures containing naphthopyrans and how they are related to exposure conditions and to the concentration and molecular structure of the dopants. We are also studying the nature of the photoinduced phase transitions, and comparing the behavior with that of azobenzene-doped mixtures, in which exposure to light leads to a decrease, instead of an increase, in the order of the system.

Detection of lead in brass by laser-induced breakdown spectroscopy combined with laser-induced fluorescence

NASA Astrophysics Data System (ADS)

Goueguel, Christian; Laville, Stéphane; Loudyi, Hakim; Chaker, Mohamed; Sabsabi, Mohamad; Vidal, François

2008-06-01

Laser-Induced Breakdown Spectroscopy (LIBS) technique combined with Laser-Induced Fluorescence (LIF) is known to be a high sensitivity and high selectivity analytical technique. Although sub-ppm limits of detection (LoD) have already been demonstrated, there is still a constant and urgent need to reach lower LoDs. Here, we report results obtained for the detection of lead trace in brass samples. The plasma was produced by a Q-switched Nd:YAG laser at 1064 nm and then re-excited by a nanosecond optical parametric oscillator (OPO) laser tuned at 283.31 nm. Emission from Pb atoms was then observed at 405.78 nm. The experiments were performed in air at atmospheric pressure. We found out that the optimal conditions were obtained for an ablation fluence of 2-3 J/cm2 and inter-pulse delay of 8-10 μs. Also, excitation energy of about 200 μJ was required to maximize the Pb(I) 405.78 nm emission. Using the LIBS-LIFS technique, the LoD was estimated to be about 180 ppb over 100 laser shots, which corresponds to an improvement of about two orders of magnitude with that obtained using conventional LIBS.

A saw-less direct conversion long term evolution receiver with 25% duty-cycle LO in 130 nm CMOS technology

NASA Astrophysics Data System (ADS)

Siyuan, He; Changhong, Zhang; Liang, Tao; Weifeng, Zhang; Longyue, Zeng; Wei, Lü; Haijun, Wu

2013-03-01

A CMOS long-term evolution (LTE) direct convert receiver that eliminates the interstage SAW filter is presented. The receiver consists of a low noise variable gain transconductance amplifier (TCA), a quadrature passive current commutating mixer with a 25% duty-cycle LO, a trans-impedance amplifier (TIA), a 7th-order Chebyshev filter and programmable gain amplifiers (PGAs). A wide dynamic gain range is allocated in the RF and analog parts. A current commutating passive mixer with a 25% duty-cycle LO improves gain, noise, and linearity. An LPF based on a Tow-Thomas biquad suppresses out-of-band interference. Fabricated in a 0.13 μm CMOS process, the receiver chain achieves a 107 dB maximum voltage gain, 2.7 dB DSB NF (from PAD port), -11 dBm IIP3, and > +65 dBm IIP2 after calibration, 96 dB dynamic control range with 1 dB steps, less than 2% error vector magnitude (EVM) from 2.3 to 2.7 GHz. The total receiver (total I Q path) draws 89 mA from a 1.2-V LDO on chip supply.

Structure Activity Relationship Studies of Flavonoids as Potent Inhibitors of Human Platelet 12-hLO, Reticulocyte 15-hLO-1 and Prostate Epithelial 15-hLO-2

PubMed Central

Vasquez-Martinez, Yesseny; Ohri, Rachana V.; Kenyon, Victor; Holman, Theodore R.; Sepúlveda-Boza, Silvia

2007-01-01

Human lipoxygenase (hLO) isozymes have been implicated in a number of disease states and have attracted much attention with respect to their inhibition. One class of inhibitors, the flavonoids, have been shown to be potent lipoxygenase inhibitors but their study has been restricted to those compounds found in nature, which have limited structural variability. We have therefore carried out a comprehensive study to determine the structural requirements for flavonoid potency and selectivity against platelet 12-hLO, reticulocyte 15-hLO-1 and prostate epithelial 15-hLO-2. We conclude from this study that catechols are essential for high potency, that isoflavones and isoflavanones tend to select against 12-hLO, that isoflavans tend to select against 15-hLO-1, but few flavonoids target 15-hLO-2. PMID:17869117

77 FR 57633 - Self-Regulatory Organizations; EDGX Exchange, Inc.; Notice of Filing and Immediate Effectiveness...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-09-18

... liquidity'' ratio.\\11\\ The Exchange believes this amendment to Footnotes 12 and 13 supports the Exchange's... transparency for its Members. \\11\\ The ``add liquidity'' ratio is the ratio of the ``added'' flags/(``added... Exchange's fee schedule for Non-Displayed Orders that add liquidity using the Route Peg Order type.\\4\\ The...

77 FR 74699 - Self-Regulatory Organizations; NASDAQ OMX PHLX LLC; Notice of Filing and Immediate Effectiveness...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-12-17

... Change Relating to Rebates and Fees for Adding and Removing Liquidity December 11, 2012. Pursuant to... Schedule entitled ``Rebates and Fees for Adding and Removing Liquidity in Select Symbols'' in order to... Adding Liquidity from $0.30 to $0.32 per contract, (2) create a new Complex Order Rebate for Removing...

Nature of the first-order liquid-liquid phase transition in supercooled silicon

NASA Astrophysics Data System (ADS)

Zhao, G.; Yu, Y. J.; Tan, X. M.

2015-08-01

The first-order liquid-liquid phase transition in supercooled Si is revisited by long-time first-principle molecular dynamics simulations. As the focus of the present paper, its nature is revealed by analyzing the inherent structures of low-density liquid (LDL) and high-density liquid (HDL). Our results show that it is a transition between a sp3-hybridization LDL and a white-tin-like HDL. This uncovers the origin of the semimetal-metal transition accompanying it and also proves that HDL is the metastable extension of high temperature equilibrium liquid into the supercooled regime. The pressure-temperature diagram of supercooled Si thus can be regarded in some respects as shifted reflection of its crystalline phase diagram.

Nonlinear vibrational spectroscopy of surfactants at liquid interfaces

NASA Astrophysics Data System (ADS)

Miranda, Paulo Barbeitas

Surfactants are widely used to modify physical and chemical properties of interfaces. They play an important role in many technological problems. Surfactant monolayers are also of great scientific interest because they are two-dimensional systems that may exhibit a very rich phase transition behavior and can also be considered as a model system for biological interfaces. In this Thesis, we use a second-order nonlinear optical technique (Sum-Frequency Generation - SFG) to obtain vibrational spectra of surfactant monolayers at liquid/vapor and solid/liquid interfaces. The technique has several advantages: it is intrinsically surface-specific, can be applied to buried interfaces, has submonolayer sensitivity and is remarkably sensitive to the conformational order of surfactant monolayers. The first part of the Thesis is concerned with surfactant monolayers at the air/water interface (Langmuir films). Surface crystallization of an alcohol Langmuir film and of liquid alkanes are studied and their phase transition behaviors are found to be of different nature, although driven by similar intermolecular interactions. The effect of crystalline order of Langmuir monolayers on the interfacial water structure is also investigated. It is shown that water forms a well-ordered hydrogen-bonded network underneath an alcohol monolayer, in contrast to a fatty acid monolayer which induces a more disordered structure. In the latter case, ionization of the monolayer becomes more significant with increase of the water pH value, leading to an electric-field-induced ordering of interfacial water molecules. We also show that the orientation and conformation of fairly complicated molecules in a Langmuir monolayer can be completely mapped out using a combination of SFG and second harmonic generation (SHG). For a quantitative analysis of molecular orientation at an interface, local-field corrections must be included. The second part is a study of self-assembled surfactant monolayers at the solid/liquid interface. It is shown that the conformation of a monolayer adsorbed onto a solid substrate and immersed in a liquid is highly dependent on the monolayer surface density and on the nature of intermolecular interactions in the liquid. Fully packed monolayers are well ordered in any environment due to strong surfactant-surfactant interactions and limited liquid penetration into the monolayer. In contrast, loosely packed monolayers are very sensitive to the liquid environment. Non-polar liquids cause a mild increase in the surfactant conformational disorder. Polar liquids induce more disorder and hydrogen-bonding liquids produce highly disordered conformations due to the hydrophobic effect. When immersed in alkanes, under certain conditions the surfactant chains may become highly ordered due to their interaction with the liquid molecules (chain-chain interaction). In the case of long-chain alcohols, competition between the hydrophobic effect and chain-chain interaction is observed.

"Learning the Basics": Young People's Engagement with Sexuality Education at Secondary Schools

ERIC Educational Resources Information Center

Adams Tucker, Leigh; George, Gavin; Reardon, Candice; Panday, Saadhna

2016-01-01

School-based sexuality education remains a key response to the HIV epidemic. Drawing on findings from an ethnographic study, this study explores how young people engage with sexuality and HIV- and AIDS-related education as it is delivered through the Life Orientation (LO) learning area in South Africa, in order to understand the dynamics that…

The Addition of Saccharin to Taste Cues Affects Taste Preference Conditioning in Thirsty Rats

ERIC Educational Resources Information Center

Forestell, Catherine A.; LoLordo, Vincent M.

2004-01-01

Previous failures to condition preferences for the unacceptable taste cues sucrose octaacetate (SOA) and citric acid (CA) using a reverse-order, differential conditioning procedure (Forestell & LoLordo, 2000) may have been the result of low consumption of the taste cues in training or of their relatively low acceptability to rats that are thirsty…

Dynamics and diffusion mechanism of low-density liquid silicon

DOE PAGES

Shen, B.; Wang, Z. Y.; Dong, F.; ...

2015-11-05

A first-order phase transition from a high-density liquid to a low-density liquid has been proposed to explain the various thermodynamic anomies of water. It also has been proposed that such liquid–liquid phase transition would exist in supercooled silicon. Computer simulation studies show that, across the transition, the diffusivity drops roughly 2 orders of magnitude, and the structures exhibit considerable tetrahedral ordering. The resulting phase is a highly viscous, low-density liquid silicon. Investigations on the atomic diffusion of such a novel form of liquid silicon are of high interest. Here we report such diffusion results from molecular dynamics simulations using themore » classical Stillinger–Weber (SW) potential of silicon. We show that the atomic diffusion of the low-density liquid is highly correlated with local tetrahedral geometries. We also show that atoms diffuse through hopping processes within short ranges, which gradually accumulate to an overall random motion for long ranges as in normal liquids. There is a close relationship between dynamical heterogeneity and hopping process. We point out that the above diffusion mechanism is closely related to the strong directional bonding nature of the distorted tetrahedral network. Here, our work offers new insights into the complex behavior of the highly viscous low density liquid silicon, suggesting similar diffusion behaviors in other tetrahedral coordinated liquids that exhibit liquid–liquid phase transition such as carbon and germanium.« less

Quantifying, Visualizing, and Monitoring Lead Optimization.

PubMed

Maynard, Andrew T; Roberts, Christopher D

2016-05-12

Although lead optimization (LO) is by definition a process, process-centric analysis and visualization of this important phase of pharmaceutical R&D has been lacking. Here we describe a simple statistical framework to quantify and visualize the progression of LO projects so that the vital signs of LO convergence can be monitored. We refer to the resulting visualizations generated by our methodology as the "LO telemetry" of a project. These visualizations can be automated to provide objective, holistic, and instantaneous analysis and communication of LO progression. This enhances the ability of project teams to more effectively drive LO process, while enabling management to better coordinate and prioritize LO projects. We present the telemetry of five LO projects comprising different biological targets and different project outcomes, including clinical compound selection, termination due to preclinical safety/tox, and termination due to lack of tractability. We demonstrate that LO progression is accurately captured by the telemetry. We also present metrics to quantify LO efficiency and tractability.

Application of the anisotropic bond model to second-harmonic generation from amorphous media

NASA Astrophysics Data System (ADS)

Adles, E. J.; Aspnes, D. E.

2008-04-01

As a step toward analyzing second-harmonic generation (SHG) from crystalline Si nanospheres in glass, we develop an anisotropic bond model (ABM) that expresses SHG in terms of physically meaningful parameters and provide a detailed understanding of the basic physics of SHG on the atomic scale. Nonlinear-optical (NLO) responses are calculated classically via the four fundamental steps of optics: evaluate the local field at a given bond site, solve the force equation for the acceleration of the charge, calculate the resulting radiation, then superpose the radiation from all charges. Because the emerging NLO signals are orders of magnitude weaker and occur at wavelengths different from that of the pump beam, these steps are independent. Paradoxically, the treatment of NLO is therefore simpler than that of linear optics (LO), where these calculations must be done self-consistently. The ABM goes beyond previous bond models by including the complete set of underlying contributions: retardation (RD), spatial-dispersion (SD), and magnetic (MG) effects, in addition to the anharmonic restoring force acting on the bond charge. Transverse as well as longitudinal motion is also considered. We apply the ABM to obtain analytic expressions for SHG from amorphous materials under Gaussian-beam excitation. These materials represent an interesting test case not only because they are ubiquitous but also because the anharmonic-force contribution that dominates the SHG response of crystalline materials and ordered interfaces vanishes by symmetry. The remaining contributions, and hence the SHG signals, are entirely functions of the LO response and beam geometry, so the only new information available is the anisotropy of the LO response at the bond level. The RD, SD, and MG contributions are all of the same order of magnitude, so none can be ignored. Diffraction is important in determining not only the pattern of the emerging beam but also the phases and amplitudes of the different terms. The plane-wave expansion that gives rise to electric quadrupole magnetic dipole effects in LO appears here as retardation. Using the paraxial-ray approximation, we reduce the results to the isotropic case in two limits, that where the linear restoring force dominates (glasses) and that where it is absent (metals). Both forward- and backscattering geometries are discussed. Estimated signal strengths and conversion efficiencies for fused silica appear to be in general agreement with data where available. Predictions that allow additional critical tests of these results are made.

Compact Receiver Front Ends for Submillimeter-Wave Applications

NASA Technical Reports Server (NTRS)

Mehdi, Imran; Chattopadhyay, Goutam; Schlecht, Erich T.; Lin, Robert H.; Sin, Seth; Peralta, Alejandro; Lee, Choonsup; Gill, John J.; Gulkis, Samuel; Thomas, Bertrand C.

2012-01-01

The current generation of submillimeter-wave instruments is relatively mass and power-hungry. The receiver front ends (RFEs) of a submillimeter instrument form the heart of the instrument, and any mass reduction achieved in this subsystem is propagated through the instrument. In the current implementation, the RFE consists of different blocks for the mixer and LO circuits. The motivation for this work is to reduce the mass of the RFE by integrating the mixer and LO circuits in one waveguide block. The mixer and its associated LO chips will all be packaged in a single waveguide package. This will reduce the mass of the RFE and also provide a number of other advantages. By bringing the mixer and LO circuits close together, losses in the waveguide will be reduced. Moreover, the compact nature of the block will allow for better thermal control of the block, which is important in order to reduce gain fluctuations. A single waveguide block with a 600- GHz RFE functionality (based on a subharmonically pumped Schottky diode pair) has been demonstrated. The block is about 3x3x3 cubic centimeters. The block combines the mixer and multiplier chip in a single package. 3D electromagnetic simulations were carried out to design the waveguide circuit around the mixer and multiplier chip. The circuit is optimized to provide maximum output power and maximum bandwidth. An integrated submillimeter front end featuring a 520-600-GHz sub-harmonic mixer and a 260-300-GHz frequency tripler in a single cavity was tested. Both devices used GaAs MMIC membrane planar Schottky diode technology. The sub-harmonic mixer/tripler circuit has been tested using conventional metal-machined blocks. Measurement results on the metal block give best DSB (double sideband) mixer noise temperature of 2,360 K and conversion losses of 7.7 dB at 520 GHz. The LO input power required to pump the integrated tripler/sub-harmonic mixer is between 30 and 50 mW.

77 FR 74536 - Self-Regulatory Organizations; National Stock Exchange, Inc.; Notice of Filing and Immediate...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-12-14

... Participants will post additional liquidity on the Exchange if it (i) increases the rebate to $0.0030 per share when the Order Deliver [sic] Participant adds liquidity in a security quoted at a price of $1.00 or... ETP Holders with an incentive to post additional liquidity on the Exchange via Order Delivery Mode...

77 FR 8936 - Self-Regulatory Organizations; the NASDAQ Stock Market LLC; Notice of Filing and Immediate...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-02-15

... defined as ``the ratio of (A) the total number of liquidity-providing orders entered by a member through... trading sessions. (3) The ratio between shares of liquidity provided through the MPID and total shares..., or pre-market and/or post- market hours; and to maintain a high ratio of liquidity provision to order...

Binding in pair potentials of liquid simple metals from nonlocality in electronic kinetic energy

NASA Technical Reports Server (NTRS)

Perrot, F.; March, N. H.

1990-01-01

The paper presents an explicit expression for the pair potential in liquid simple metals from low-order density-gradient theory when the superposition of single-center displaced charges is employed. Numerical results are presented for the gradient expansion pair interaction in liquid Na and Be. The low-order density-gradient equation for the pair potential is presented.

Human CD34(lo)CD133(lo) fetal liver cells support the expansion of human CD34(hi)CD133(hi) hematopoietic stem cells.

PubMed

Yong, Kylie Su Mei; Keng, Choong Tat; Tan, Shu Qi; Loh, Eva; Chang, Kenneth Te; Tan, Thiam Chye; Hong, Wanjin; Chen, Qingfeng

2016-09-01

We have recently discovered a unique CD34(lo)CD133(lo) cell population in the human fetal liver (FL) that gives rise to cells in the hepatic lineage. In this study, we further characterized the biological functions of FL CD34(lo)CD133(lo) cells. Our findings show that these CD34(lo)CD133(lo) cells express markers of both endodermal and mesodermal lineages and have the capability to differentiate into hepatocyte and mesenchymal lineage cells by ex vivo differentiation assays. Furthermore, we show that CD34(lo)CD133(lo) cells express growth factors that are important for human hematopoietic stem cell (HSC) expansion: stem cell factor (SCF), insulin-like growth factor 2 (IGF2), C-X-C motif chemokine 12 (CXCL12), and factors in the angiopoietin-like protein family. Co-culture of autologous FL HSCs and allogenic HSCs derived from cord blood with CD34(lo)CD133(lo) cells supports and expands both types of HSCs.These findings are not only essential for extending our understanding of the HSC niche during the development of embryonic and fetal hematopoiesis but will also potentially benefit adult stem cell transplantations in clinics because expanded HSCs demonstrate the same capacity as primary cells to reconstitute the human immune system and mediate long-term hematopoiesis in vivo. Together, CD34(lo)CD133(lo) cells not only serve as stem/progenitor cells for liver development but are also an essential component of the HSC niche in the human FL.

[Effects of different hypoxic training modes on activities of mitochondrial antioxidants and respiratory chain complex in skeletal muscle after exhaustive running in rat].

PubMed

Li, Jie; Zhang, Yao-Bin

2011-02-25

The present study was aimed to investigate the effect of hypoxic training on mitochondrial antioxidants and activities of respiratory chain complexes in mitochondria of skeletal muscle in rats. Forty healthy male Wistar rats were randomized to 5 groups (n=8): living low-training low (LoLo), living high-training high (HiHi), living high-training low (HiLo), living low-training high (LoHi), and living high-exercise high-training low (HiHiLo). All the animals were subjected to 5-week training in normoxic (atmospheric pressure=632 mmHg, altitude of about 1 500 m) or hypoxic environment (atmospheric pressure=493 mmHg, simulated altitude of about 3 500 m). Before exhaustive running, the animals stayed in normoxia for 3 d. Skeletal muscles were prepared immediately after exhaustive running. Muscle mitochondria were extracted by differential centrifugation. Spectrophotometric analysis was used to evaluate activities of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), catalase (CAT), malondialdehyde (MDA) level and respiratory chain complex (C) I-III activities in muscle homogenate and mitochondria. Results showed that SOD, GSH-Px, CAT activities and MDA level in skeletal muscle homogenate in HiHi and HiHiLo groups were significantly increased (P<0.05 or P<0.01) compared with those in LoLo group. Muscle mitochondrial MDA level in HiHi and HiHiLo groups was significantly lower (P<0.01), while activities of SOD, GSH-Px and CAT were remarkably higher (P<0.01) than those in LoLo group. Meanwhile, C I-III activities in HiHi and HiHiLo groups were increased significantly (P<0.01), and C II activity in HiLo group also was increased remarkably (P<0.01) compared with those in LoLo group. These results suggest that HiHiLo might be an ideal hypoxic training mode.

Long-range dipolar order and dispersion forces in polar liquids

NASA Astrophysics Data System (ADS)

Besford, Quinn Alexander; Christofferson, Andrew Joseph; Liu, Maoyuan; Yarovsky, Irene

2017-11-01

Complex solvation phenomena, such as specific ion effects, occur in polar liquids. Interpretation of these effects in terms of structure and dispersion forces will lead to a greater understanding of solvation. Herein, using molecular dynamics, we probe the structure of polar liquids through specific dipolar pair correlation functions that contribute to the potential of mean force that is "felt" between thermally rotating dipole moments. It is shown that unique dipolar order exists at separations at least up to 20 Å for all liquids studied. When the structural order is compared with a dipolar dispersion force that arises from local co-operative enhancement of dipole moments, a strong agreement is found. Lifshitz theory of dispersion forces was compared with the structural order, where the theory is validated for all liquids that do not have significant local dipole correlations. For liquids that do have significant local dipole correlations, specifically liquid water, Lifshitz theory underestimates the dispersion force by a factor of 5-10, demonstrating that the force that leads to the increased structure in liquid water is missed by Lifshitz theory of van der Waals forces. We apply similar correlation functions to an ionic aqueous system, where long-range order between water's dipole moment and a single chloride ion is found to exist at 20 Å of separation, revealing a long-range perturbation of water's structure by an ion. Furthermore, we found that waters within the 1st, 2nd, and 3rd solvation shells of a chloride ion exhibit significantly enhanced dipolar interactions, particularly with waters at larger distances of separation. Our results provide a link between structures, dispersion forces, and specific ion effects, which may lead to a more robust understanding of solvation.

The Eclipsing Central Stars of the Planetary Nebulae Lo 16 and PHR J1040-5417

NASA Astrophysics Data System (ADS)

Hillwig, Todd C.; Frew, David; Jones, David; Crispo, Danielle

2017-01-01

Binary central stars of planetary nebula are a valuable tool in understanding common envelope evolution. In these cases both the resulting close binary system and the expanding envelope (the planetary nebula) can be studied directly. In order to compare observed systems with common envelope evolution models we need to determine precise physical parameters of the binaries and the nebulae. Eclipsing central stars provide us with the best opportunity to determine high precision values for mass, radius, and temperature of the component stars in these close binaries. We present photometry and spectroscopy for two of these eclipsing systems; the central stars of Lo 16 and PHR 1040-5417. Using light curves and radial velocity curves along with binary modeling we provide physical parameters for the stars in both of these systems.

Measurement of subvisible particulates in lyophilised Erwinia chrysanthemi L-asparaginase and relationship with clinical experience.

PubMed

Gervais, David; Corn, Tim; Downer, Andrew; Smith, Stuart; Jennings, Alan

2014-07-01

In order to generate further characterisation data for the lyophilised product Erwinia chrysanthemi L-asparaginase, reconstituted drug product (DP; marketed as Erwinase or Erwinaze) was analysed for subvisible (2-10 μm) particulate content using both the light obscuration (LO) method and the newer flow-imaging microscopy (FIM) technique. No correlation of subvisible particulate counts exists between FIM and LO nor do the counts correlate with activity at both release and on stability. The subvisible particulate content of lyophilised Erwinia L-asparaginase appears to be consistent and stable over time and in line with other parenteral biopharmaceutical products. The majority (ca. 75%) of subvisible particulates in L-asparaginase DP were at the low end of the measurement range by FIM (2-4 μm). In this size range, FIM was unable to definitively classify the particulates as either protein or non-protein. More sensitive measurement techniques would be needed to classify the particulates in lyophilised L-asparaginase into type (protein and non-protein), so the LO technique has been chosen for on-going DP analyses. E. chrysanthemi L-asparaginase has a lower rate of hypersensitivity compared with native Escherichia coli preparations, but a subset of patients develop hypersensitivity to the Erwinia enzyme. A DP lot that had subvisible particulate counts on the upper end of the measurement range by both LO and FIM had the same incidence of allergic hypersensitivity in clinical experience as lots at all levels of observed subvisible particulate content, suggesting that the presence of L-asparaginase subvisible particulates is not important with respect to allergic response.

Performance Evaluation of LoRa Considering Scenario Conditions.

PubMed

Sanchez-Iborra, Ramon; Sanchez-Gomez, Jesus; Ballesta-Viñas, Juan; Cano, Maria-Dolores; Skarmeta, Antonio F

2018-03-03

New verticals within the Internet of Things (IoT) paradigm such as smart cities, smart farming, or goods monitoring, among many others, are demanding strong requirements to the Radio Access Network (RAN) in terms of coverage, end-node's power consumption, and scalability. The technologies employed so far to provide IoT scenarios with connectivity, e.g., wireless sensor network and cellular technologies, are not able to simultaneously cope with these three requirements. Thus, a novel solution known as Low Power - Wide Area Network (LP-WAN) has emerged as a promising alternative to provide with low-cost and low-power-consumption connectivity to end-nodes spread in a wide area. Concretely, the Long-Range Wide Area Network (LoRaWAN) technology is one of the LP-WAN platforms that is receiving greater attention from both the industry and the academia. For that reason, in this work, a comprehensive performance evaluation of LoRaWAN under different environmental conditions is presented. The results are obtained from three real scenarios, namely, urban, suburban, and rural, considering both dynamic and static conditions, hence a discussion about the most proper LoRaWAN physical-layer configuration for each scenario is provided. Besides, a theoretical coverage study is also conducted by the use of a radio planning tool considering topographic maps and a precise propagation model. From the attained results, it can be concluded that it is necessary to evaluate the propagation conditions of the deployment scenario prior to the system implantation in order to reach a compromise between the robustness of the network and the transmission data-rate.

Performance Evaluation of LoRa Considering Scenario Conditions

PubMed Central

Sanchez-Gomez, Jesus; Ballesta-Viñas, Juan

2018-01-01

New verticals within the Internet of Things (IoT) paradigm such as smart cities, smart farming, or goods monitoring, among many others, are demanding strong requirements to the Radio Access Network (RAN) in terms of coverage, end-node’s power consumption, and scalability. The technologies employed so far to provide IoT scenarios with connectivity, e.g., wireless sensor network and cellular technologies, are not able to simultaneously cope with these three requirements. Thus, a novel solution known as Low Power - Wide Area Network (LP-WAN) has emerged as a promising alternative to provide with low-cost and low-power-consumption connectivity to end-nodes spread in a wide area. Concretely, the Long-Range Wide Area Network (LoRaWAN) technology is one of the LP-WAN platforms that is receiving greater attention from both the industry and the academia. For that reason, in this work, a comprehensive performance evaluation of LoRaWAN under different environmental conditions is presented. The results are obtained from three real scenarios, namely, urban, suburban, and rural, considering both dynamic and static conditions, hence a discussion about the most proper LoRaWAN physical-layer configuration for each scenario is provided. Besides, a theoretical coverage study is also conducted by the use of a radio planning tool considering topographic maps and a precise propagation model. From the attained results, it can be concluded that it is necessary to evaluate the propagation conditions of the deployment scenario prior to the system implantation in order to reach a compromise between the robustness of the network and the transmission data-rate. PMID:29510524

The first 62 AGNs observed with SDSS-IV MaNGA - I. Their characterization and definition of a control sample

NASA Astrophysics Data System (ADS)

Rembold, Sandro B.; Shimoia, Jáderson S.; Storchi-Bergmann, Thaisa; Riffel, Rogério; Riffel, Rogemar A.; Mallmann, Nícolas D.; do Nascimento, Janaína C.; Moreira, Thales N.; Ilha, Gabriele S.; Machado, Alice D.; Cirolini, Rafael; da Costa, Luiz N.; Maia, Marcio A. G.; Santiago, Basílio X.; Schneider, Donald P.; Wylezalek, Dominika; Bizyaev, Dmitry; Pan, Kaike; Müller-Sánchez, Francisco

2017-12-01

We report the characterization of the first 62 Mapping Nearby Galaxies at the Apache Point Observatory active galactic nuclei (AGNs) hosts and the definition of a control sample of non-active galaxies. This control sample was selected in order to match the AGN hosts in terms of stellar mass, redshift, visual morphology and inclination. The stellar masses are in the range 9.4

Strawberry-Tree Honey Induces Growth Inhibition of Human Colon Cancer Cells and Increases ROS Generation: A Comparison with Manuka Honey

PubMed Central

Afrin, Sadia; Forbes-Hernandez, Tamara Y.; Gasparrini, Massimiliano; Bompadre, Stefano; Quiles, José L.; Sanna, Gavino; Spano, Nadia; Giampieri, Francesca; Battino, Maurizio

2017-01-01

Honey is a natural product known to modulate several biological activities including cancer. The aim of the present study was to examine the phytochemical content and the antioxidant activity of Strawberry tree (Arbutus unedo) honey (STH) and its cytotoxic properties against human colon adenocarcinoma (HCT-116) and metastatic (LoVo) cell lines in comparison with Manuka (Leptospermum scoparium) honey (MH). Several unifloral STH and MH were analyzed for their phenolic, flavonoid, amino acid and protein contents, as well as their radical scavenging activities. STH from the Berchidda area showed the highest amount of phenolic, flavonoid, amino acid and protein content, and antioxidant capacity compared to MH. Both STH and MH induced cytotoxicity and cell death in a dose- and time-dependent manner in HCT-116 and LoVo cells, with less toxicity on non-cancer cells. Compared to MH, STH showed more effect at lower concentrations on HCT-116 and LoVo cells. In addition, both honeys increased intracellular reactive oxygen species (ROS) generation. In HCT-116 cells, STH and MH induced similar ROS production but in LoVo cells STH induced a higher percentage of ROS compared to MH. Our results indicate that STH and MH can induce cell growth inhibition and ROS generation in colon adenocarcinoma and metastatic cells, which could be due to the presence of phytochemicals with antioxidant properties. These preliminary results are interesting and suggest a potential chemopreventive action which could be useful for further studies in order to develop chemopreventive agents for colon cancer. PMID:28287469

Theoretical Studies of Nonuniform Orientational Order in Liquid Crystals and Active Particles

NASA Astrophysics Data System (ADS)

Duzgun, Ayhan

I investigate three systems that exhibit complex patterns in orientational order, which are controlled by geometry interacting with the dynamics of phase transitions, metastability, and activity. 1. Liquid Crystal Elastomers: Liquid-crystal elastomers are remarkable materials that combine the elastic properties of cross-linked polymer networks with the anisotropy of liquid crystals. Any distortion of the polymer network affects the nematic order of the liquid crystal, and, likewise, any change in the magnitude or direction of the nematic order influences the shape of the elastomer. When elastomers are prepared without any alignment, they develop disordered polydomain structures as they are cooled into the nematic phase. To model these polydomain structures, I develop a dynamic theory for the isotropic-nematic transition in elastomers. 2. Active Brownian Particles: Unlike equilibrium systems, active matter is not governed by the conventional laws of thermodynamics. I perform Langevin dynamics simulations and analytic calculations to explore how systems cross over from equilibrium to active behavior as the activity is increased. Based on these results, I calculate how the pressure depends on wall curvature, and hence make analytic predictions for the motion of curved tracers and other effects of confinement in active matter systems. 3. Skyrmions in Liquid Crystals: Skyrmions are localized topological defects in the orientation of an order parameter field, without a singularity in the magnitude of the field. For many years, such defects have been studied in the context of chiral liquid crystals--for example, as bubbles in a confined cholesteric phase or as double-twist tubes in a blue phase. More recently, skyrmions have been investigated extensively in the context of chiral magnets. In this project, I compare skyrmions in chiral liquid crystals with the analogous magnetic defects. Through simulations based on the nematic order tensor, I model both isolated skyrmions and periodic defect lattices.

Two-order-parameter description of liquid Al under five different pressures

NASA Astrophysics Data System (ADS)

Li, Y. D.; Hao, Qing-Hai; Cao, Qi-Long; Liu, C. S.

2008-11-01

In the present work, using the glue potential, the constant pressure molecular-dynamics simulations of liquid Al under five various pressures and a systematic analysis of the local atomic structures have been performed in order to test the two-order-parameter model proposed by Tanaka [Phys. Rev. Lett. 80, 5750 (1998)] originally for explaining the unusual behaviors of liquid water. The temperature dependence of the bond order parameter Q6 in liquid Al under five different pressures can be well fitted by the functional expression (Q6)/(1-Q6)=Q60exp((ΔE-PΔV)/(kBT)) which produces the energy gain ΔE and the volume change upon the formation of a locally favored structure: ΔE=0.025eV and ΔV=-0.27(Å)3 . ΔE is nearly equal to the difference between the average bond energy of the other type I bonds and the average bond energy of 1551 bonds (characterizing the icosahedronlike local structure); ΔV could be explained as the average volume occupied by one atom in icosahedra minus that occupied by one atom in other structures. With the obtained ΔE and ΔV , it is satisfactorily explained that the density of liquid Al displays a much weaker nonlinear dependence on temperature under lower pressures. So it is demonstrated that the behavior of liquid Al can be well described by the two-order-parameter model.

Landau parameters for energy density functionals generated by local finite-range pseudopotentials

NASA Astrophysics Data System (ADS)

Idini, A.; Bennaceur, K.; Dobaczewski, J.

2017-06-01

In Landau theory of Fermi liquids, the particle-hole interaction near the Fermi energy in different spin-isospin channels is probed in terms of an expansion over the Legendre polynomials. This provides a useful and efficient way to constrain properties of nuclear energy density functionals in symmetric nuclear matter and finite nuclei. In this study, we present general expressions for Landau parameters corresponding to a two-body central local regularized pseudopotential. We also show results obtained for two recently adjusted NLO and N2LO parametrizations. Such pseudopotentials will be used to determine mean-field and beyond-mean-field properties of paired nuclei across the entire nuclear chart.

Cryo Tank Fill at Pad 39B

NASA Image and Video Library

2017-09-26

Several Praxair trucks begin to depart Launch Pad 39B at NASA's Kennedy Space Center in Florida, after offloading their loads of liquid oxygen, or LO2, one at a time into the giant storage sphere located at the northwest corner of the pad. The sphere was gradually chilled down from normal temperature to about negative 298 degrees Fahrenheit, during the first major integrated operation to prepare for the launch of the agency's Orion spacecraft atop the Space Launch System (SLS) rocket. The Ground Systems Development and Operations Program is overseeing upgrades and modifications to pad B to support the launch of the SLS and Orion spacecraft for Exploration Mission-1, deep space missions and NASA’s journey to Mars.

Cryo Tank Fill at Pad 39B

NASA Image and Video Library

2017-09-26

Mist or vapor is visible as a Praxair truck slowly transfers its load of liquid oxygen, or LO2, into a giant storage sphere at the northwest corner of Launch Pad 39B at NASA's Kennedy Space Center in Florida. The sphere will gradually be chilled down from normal temperature to about negative 298 degrees Fahrenheit, during the first major integrated operation to prepare for the launch of the agency's Orion spacecraft atop the Space Launch System (SLS) rocket. The Ground Systems Development and Operations Program is overseeing upgrades and modifications to pad B to support the launch of the SLS and Orion spacecraft for Exploration Mission-1, deep space missions and NASA’s journey to Mars.

76 FR 41626 - Certain Orderly Liquidation Authority Provisions under Title II of the Dodd-Frank Wall Street...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-07-15

... States'' include only amounts advanced to the covered financial company to promote the orderly resolution... (``Final Rule'') to implement certain provisions of its authority to resolve covered financial companies... the orderly liquidation of a systemically important financial institution under the Dodd-Frank Act...

Comparison of short-range-order in liquid- and rotator-phase states of a simple molecular liquid: A reverse Monte Carlo and molecular dynamics analysis of neutron diffraction data

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pardo, Luis Carlos; Tamarit, Josep Lluis; Veglio, Nestor

2007-10-01

The short-range order (SRO) correlations in liquid- and rotator-phase states of carbon tetrachloride are revisited here. The correlation of some angular magnitudes is used to evaluate the positional and orientational correlations in the liquid as well as in the rotator phase. The results show significant similitudes in the relative position of the molecules surrounding a central one but striking differences in their relative orientations, which could explain the changes in SRO between the two phases and the puzzling behavior of the local density in the liquid and rotator phases.

Conductance scaling of junctions of Luttinger-liquid wires out of equilibrium

NASA Astrophysics Data System (ADS)

Aristov, D. N.; Wölfle, P.

2018-05-01

We develop the renormalization group theory of the conductances of N -lead junctions of spinless Luttinger-liquid wires as functions of bias voltages applied to N independent Fermi-liquid reservoirs. Based on the perturbative results up to second order in the interaction we demonstrate that the conductances obey scaling. The corresponding renormalization group β functions are derived up to second order.

77 FR 50185 - LoCorr Fund Management, LLC and LoCorr Investment Trust; Notice of Application

Federal Register 2010, 2011, 2012, 2013, 2014

2012-08-20

... Fund Management, LLC and LoCorr Investment Trust; Notice of Application August 14, 2012. AGENCY.... Applicants: LoCorr Fund Management, LLC (``LFM'' or the ``Adviser'') and LoCorr Investment Trust (the ``Trust... Mary Kay Frech, Branch Chief, at (202) 551-6821 (Division of Investment Management, Office of...

Self-assembled ordered structures in thin films of HAT5 discotic liquid crystal.

PubMed

Morales, Piero; Lagerwall, Jan; Vacca, Paolo; Laschat, Sabine; Scalia, Giusy

2010-05-20

Thin films of the discotic liquid crystal hexapentyloxytriphenylene (HAT5), prepared from solution via casting or spin-coating, were investigated by atomic force microscopy and polarizing optical microscopy, revealing large-scale ordered structures substantially different from those typically observed in standard samples of the same material. Thin and very long fibrils of planar-aligned liquid crystal were found, possibly formed as a result of an intermediate lyotropic nematic state arising during the solvent evaporation process. Moreover, in sufficiently thin films the crystallization seems to be suppressed, extending the uniform order of the liquid crystal phase down to room temperature. This should be compared to the bulk situation, where the same material crystallizes into a polymorphic structure at 68 °C.

Research and Teaching: Eight Is Not Enough--The Level of Questioning and Its Impact on Learning in Clicker Cases

ERIC Educational Resources Information Center

Terry, David R.; Lemons, Paula; Armstrong, Norris; Brickman, Peggy; Ribbens, Eric; Herreid, Clyde Freeman

2016-01-01

Three college faculty taught large general biology classes using case studies and personal response systems (clickers). Each instructor taught the same eight cases in two different sections, except the questions within the cases differed. In one section the questions were lower order (LO) factual inquiries, and in the other they were largely…

Symmetric Gain Optoelectronic Mixers for LADAR

DTIC Science & Technology

2008-12-01

photodetector in the receiver is used as an optoelectronic mixer (OEM). Adding gain to the optoelectronic mixer allows the following transimpedance ...output is the low frequency difference signal, several orders of magnitude lower than the LO signal. Therefore, the gain of the transimpedance ... amplifier (TZA) following the photodetector can be increased, improving LADAR range. The metal-semiconductor- metal (MSM) Schottky detector is such a

Measurement characteristics of the levels of institutionalization scales: examining reliability and validity.

PubMed

Barab, S A; Redman, B K; Froman, R D

1998-01-01

The Level of Institutionalization (LoIn) scales were developed to assess the extent to which a health promotion program has become integrated into a health care organization. The instrument was designed specifically to measure the amount of routinization and niche saturation of four subsystems (production, maintenance, supportive, and managerial) believed to make up an organization. In this study, the LoIn scales were completed for diabetes programs in 102 general hospitals and 30 home health agencies in Maryland and Pennsylvania. Reliability estimates across the four subsystems for routines (alpha = .61) and for niche saturation (alpha = .44) were substandard. Average correlation among the four subsystems for routines was .67, and among the four subsystems for niche saturation was .38, indicating moderate to large amounts of shared variance among subsystems and challenging claims of discriminant validity. Given these large correlations and a poor fit when testing the eight-factor model, higher-order confirmatory factor analyses were carried out. Results supported the existence of two second-order factors. When collapsed into two factors, the reliabilities were adequate (routines alpha = .90; niche saturation alpha = .80). Criterion-related validity also was found between length of program existence and the routine factor.

Magnetically Actuated Propellant Orientation Experiment, Controlling Fluid Motion With Magnetic Fields in a Low-Gravity Environment

NASA Technical Reports Server (NTRS)

Martin, J. J.; Holt, J. B.

2000-01-01

This report details the results of a series of fluid motion experiments to investigate the use of magnets to orient fluids in a low-gravity environment. The fluid of interest for this project was liquid oxygen (LO2) since it exhibits a paramagnetic behavior (is attracted to magnetic fields). However, due to safety and handling concerns, a water-based ferromagnetic mixture (produced by Ferrofluidics Corporation) was selected to simplify procedures. Three ferromagnetic fluid mixture strengths and a nonmagnetic water baseline were tested using three different initial fluid positions with respect to the magnet. Experiment accelerometer data were used with a modified computational fluid dynamics code termed CFX-4 (by AEA Technologies) to predict fluid motion. These predictions compared favorably with experiment video data, verifying the code's ability to predict fluid motion with and without magnetic influences. Additional predictions were generated for LO2 with the same test conditions and geometries used in the testing. Test hardware consisted of a cylindrical Plexiglas tank (6-in. bore with 10-in. length), a 6,000-G rare Earth magnet (10-in. ring), three-axis accelerometer package, and a video recorder system. All tests were conducted aboard the NASA Reduced-Gravity Workshop, a KC-135A aircraft.

Evaluation of a gas chromatography method for azelaic acid determination in selected biological samples

PubMed Central

Garelnabi, Mahdi; Litvinov, Dmitry; Parthasarathy, Sampath

2010-01-01

Background: Azelaic acid (AzA) is the best known dicarboxilic acid to have pharmaceutical benefits and clinical applications and also to be associated with some diseases pathophysiology. Materials and Methods: We extracted and methylesterified AzA and determined its concentration in human plasma obtained from healthy individuals and also in mice fed AzA containing diet for three months. Results: AzA was detected in Gas Chromatography (GC) and confirmed by Liquid chromatography mass spectrometry (LCMS), and gas chromatography mass spectrometry (GCMC). Our results have shown that AzA can be determined efficiently in selected biological samples by GC method with 1nM limit of detection (LoD) and the limit of quantification (LoQ); was established at 50nM. Analytical Sensitivity as assayed by hexane demonstrated an analytical sensitivity at 0.050nM. The method has demonstrated 8-10% CV batch repeatability across the sample types and 13-18.9% CV for the Within-Lab Precision analysis. The method has shown that AzA can efficiently be recovered from various sample preparation including liver tissue homogenate (95%) and human plasma (97%). Conclusions: Because of its simplicity and lower limit of quantification, the present method provides a useful tool for determining AzA in various biological sample preparations. PMID:22558586

Evaluation of a gas chromatography method for azelaic acid determination in selected biological samples.

PubMed

Garelnabi, Mahdi; Litvinov, Dmitry; Parthasarathy, Sampath

2010-09-01

Azelaic acid (AzA) is the best known dicarboxilic acid to have pharmaceutical benefits and clinical applications and also to be associated with some diseases pathophysiology. We extracted and methylesterified AzA and determined its concentration in human plasma obtained from healthy individuals and also in mice fed AzA containing diet for three months. AzA was detected in Gas Chromatography (GC) and confirmed by Liquid chromatography mass spectrometry (LCMS), and gas chromatography mass spectrometry (GCMC). Our results have shown that AzA can be determined efficiently in selected biological samples by GC method with 1nM limit of detection (LoD) and the limit of quantification (LoQ); was established at 50nM. Analytical Sensitivity as assayed by hexane demonstrated an analytical sensitivity at 0.050nM. The method has demonstrated 8-10% CV batch repeatability across the sample types and 13-18.9% CV for the Within-Lab Precision analysis. The method has shown that AzA can efficiently be recovered from various sample preparation including liver tissue homogenate (95%) and human plasma (97%). Because of its simplicity and lower limit of quantification, the present method provides a useful tool for determining AzA in various biological sample preparations.

Long range order and two-fluid behavior in heavy electron materials

DOE PAGES

Shirer, Kent R.; Shockley, Abigail C.; Dioguardi, Adam P.; ...

2012-09-24

The heavy electron Kondo liquid is an emergent state of condensed matter that displays universal behavior independent of material details. Properties of the heavy electron liquid are best probed by NMR Knight shift measurements, which provide a direct measure of the behavior of the heavy electron liquid that emerges below the Kondo lattice coherence temperature as the lattice of local moments hybridizes with the background conduction electrons. Because the transfer of spectral weight between the localized and itinerant electronic degrees of freedom is gradual, the Kondo liquid typically coexists with the local moment component until the material orders at lowmore » temperatures. The two-fluid formula captures this behavior in a broad range of materials in the paramagnetic state. In order to investigate two-fluid behavior and the onset and physical origin of different long range ordered ground states in heavy electron materials, we have extended Knight shift measurements to URu 2Si 2, CeIrIn 5, and CeRhIn 5. In CeRhIn 5 we find that the antiferromagnetic order is preceded by a relocalization of the Kondo liquid, providing independent evidence for a local moment origin of antiferromagnetism. In URu 2Si 2 the hidden order is shown to emerge directly from the Kondo liquid and so is not associated with local moment physics. Lastly, our results imply that the nature of the ground state is strongly coupled with the hybridization in the Kondo lattice in agreement with phase diagram proposed by Yang and Pines.« less

Stability of dense liquid carbon dioxide.

PubMed

Boates, Brian; Teweldeberhan, Amanuel M; Bonev, Stanimir A

2012-09-11

We present ab initio calculations of the phase diagram of liquid CO(2) and its melting curve over a wide range of pressure and temperature conditions, including those relevant to the Earth. Several distinct liquid phases are predicted up to 200 GPa and 10,000 K based on their structural and electronic characteristics. We provide evidence for a first-order liquid-liquid phase transition with a critical point near 48 GPa and 3,200 K that intersects the mantle geotherm; a liquid-liquid-solid triple point is predicted near 45 GPa and 1,850 K. Unlike known first-order transitions between thermodynamically stable liquids, the coexistence of molecular and polymeric CO(2) phases predicted here is not accompanied by metallization. The absence of an electrical anomaly would be unique among known liquid-liquid transitions. Furthermore, the previously suggested phase separation of CO(2) into its constituent elements at lower mantle conditions is examined by evaluating their Gibbs free energies. We find that liquid CO(2) does not decompose into carbon and oxygen up to at least 200 GPa and 10,000 K.

Liquid-liquid phase transition in an ionic model of silica

NASA Astrophysics Data System (ADS)

Chen, Renjie; Lascaris, Erik; Palmer, Jeremy C.

2017-06-01

Recent equation of state calculations [E. Lascaris, Phys. Rev. Lett. 116, 125701 (2016)] for an ionic model of silica suggest that it undergoes a density-driven, liquid-liquid phase transition (LLPT) similar to the controversial transition hypothesized to exist in deeply supercooled water. Here, we perform extensive free energy calculations to scrutinize the model's low-temperature phase behavior and confirm the existence of a first-order phase transition between two liquids with identical compositions but different densities. The low-density liquid (LDL) exhibits tetrahedral order, which is partially disrupted in the high-density liquid (HDL) by the intrusion of additional particles into the primary neighbor shell. Histogram reweighting methods are applied to locate conditions of HDL-LDL coexistence and the liquid spinodals that bound the two-phase region. Spontaneous liquid-liquid phase separation is also observed directly in large-scale molecular dynamics simulations performed inside the predicted two-phase region. Given its clear LLPT, we anticipate that this model may serve as a paradigm for understanding whether similar transitions occur in water and other tetrahedral liquids.

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Characterization of van der Waals type bimodal,- lambda,- meta- and spinodal phase transitions in liquid mixtures, solid suspensions and thin films.

PubMed

Rosenholm, Jarl B

2018-03-01

The perfect gas law is used as a reference when selecting state variables (P, V, T, n) needed to characterize ideal gases (vapors), liquids and solids. Van der Waals equation of state is used as a reference for models characterizing interactions in liquids, solids and their mixtures. Van der Waals loop introduces meta- and unstable states between the observed gas (vapor)-liquid P-V transitions at low T. These intermediate states are shown to appear also between liquid-liquid, liquid-solid and solid-solid phase transitions. First-order phase transitions are characterized by a sharp discontinuity of first-order partial derivatives (P, S, V) of Helmholtz and Gibbs free energies. Second-order partial derivatives (K T , B, C V , C P , E) consist of a static contribution relating to second-order phase transitions and a relaxation contribution representing the degree of first-order phase transitions. Bimodal (first-order) and spinodal (second-order) phase boundaries are used to separate stable phases from metastable and unstable phases. The boundaries are identified and quantified by partial derivatives of molar Gibbs free energy or chemical potentials with respect to P, S, V and composition (mole fractions). Molecules confined to spread Langmuir monolayers or adsorbed Gibbs monolayers are characterized by equation of state and adsorption isotherms relating to a two-dimensional van der Waals equation of state. The basic work of two-dimensional wetting (cohesion, adsorption, spreading, immersion), have to be adjusted by a horizontal surface pressure in the presence of adsorbed vapor layers. If the adsorption is extended to liquid films a vertical surface pressure (Π) may be added to account for the lateral interaction, thus restoring PV = ΠAh dependence of thin films. Van der Waals attraction, Coulomb repulsion and structural hydration forces contribute to the vertical surface pressure. A van der Waals type coexistence of ordered (dispersed) and disordered (aggregated) phases is shown to exist when liquid vapor is confined in capillaries (condensation-liquefaction-evaporation and flux). This pheno-menon can be experimentally illustrated with suspended nano-sized particles (flocculation-coagulation-peptisation of colloidal sols) being confined in sample holders of varying size. The self-assembled aggregates represent critical self-similar equilibrium structures corres-ponding to rate determining complexes in kinetics. Overall, a self-consistent thermodynamic framework is established for the characterization of two- and three-dimensional phase separations in one-, two- and three-component systems. Copyright © 2018 Elsevier B.V. All rights reserved.

LOX/Methane In-Space Propulsion Systems Technology Status and Gaps

NASA Technical Reports Server (NTRS)

Klem, Mark D.

2017-01-01

Human exploration architecture studies have identified liquid oxygen (LOX)Methane (LCH4) as a strong candidate for both interplanetary and descent ascent propulsion solutions. Significant research efforts into methane propulsion have been conducted for over 50 years, ranging from fundamental combustion mixing efforts to rocket chamber and system level demonstrations. Over the past 15 years NASA and its partners have built upon these early activities that have demonstrated practical components and sub-systems needed to field future methane space transportation elements. These advanced development efforts have formed a foundation of LOXLCH4 propulsion knowledge that has significantly reduced the development risks of future methane based space transportation elements for human exploration beyond earth orbit. As a bipropellant propulsion system, LOXLCH4 has some favorable characteristics for long life and reusability, which are critical to lunar and Mars missions. Non-toxic, non-corrosive, self-venting, and simple to purge. No extensive decontamination process required as with toxic propellants. High vapor pressure provides for excellent vacuum ignition characteristics. Performance is better than current earth storable propellants for human scale spacecraft. Provides the capability for future Mars exploration missions to use propellants that are produced in-situ on Mars Liquid Methane is thermally similar to O2 as a cryogenic propellant, 90,111 K (LO2, LCH4 respectively) instead of the 23 K of LH2. Allows for common components and thus providing cost savings as compared to liquid hydrogen (LH2). Due to liquid methane having a 6x higher density than hydrogen, it can be stored in much smaller volumes. Cryogenic storage aspect of these propellants needs to be addressed. Passive techniques using shielding and orientations to deep space Refrigeration may be required to maintain both oxygen and methane in liquid forms

The adaptive nature of liquidity taking in limit order books

NASA Astrophysics Data System (ADS)

Taranto, D. E.; Bormetti, G.; Lillo, F.

2014-06-01

In financial markets, the order flow, defined as the process assuming value one for buy market orders and minus one for sell market orders, displays a very slowly decaying autocorrelation function. Since orders impact prices, reconciling the persistence of the order flow with market efficiency is a subtle issue. A possible solution is provided by asymmetric liquidity, which states that the impact of a buy or sell order is inversely related to the probability of its occurrence. We empirically find that when the order flow predictability increases in one direction, the liquidity in the opposite side decreases, but the probability that a trade moves the price decreases significantly. While the last mechanism is able to counterbalance the persistence of order flow and restore efficiency and diffusivity, the first acts in the opposite direction. We introduce a statistical order book model where the persistence of the order flow is mitigated by adjusting the market order volume to the predictability of the order flow. The model reproduces the diffusive behaviour of prices at all time scales without fine-tuning the values of parameters, as well as the behaviour of most order book quantities as a function of the local predictability of the order flow.

Discovery of Platelet-Type 12-Human Lipoxygenase Selective Inhibitors by High-Throughput Screening of Structurally Diverse Libraries

PubMed Central

Deschamps, Joshua D.; Gautschi, Jeffrey T.; Whitman, Stephanie; Johnson, Tyler A.; Gassner, Nadine C.; Crews, Phillip; Holman, Theodore R.

2007-01-01

Human lipoxygenases (hLO) have been implicated in a variety of diseases and cancers and each hLO isozyme appears to have distinct roles in cellular biology. This fact emphasizes the need for discovering selective hLO inhibitors for both understanding the role of specific lipoxygenases in the cell and developing pharmaceutical therapeutics. To this end, we have modified a known lipoxygenase assay for high-throughput (HTP) screening of both the National Cancer Institute (NCI) and the UC Santa Cruz marine extract library (UCSC-MEL) in search of platelet-type 12-hLO (12-hLO) selective inhibitors. The HTP screen led to the characterization of five novel 12-hLO inhibitors from the NCI repository. One is the potent but non-selective michellamine B, a natural product, antiviral agent. The other four compounds were selective inhibitors against 12-hLO, with three being synthetic compounds and one being α-mangostin, a natural product, caspase-3 pathway inhibitor. In addition, a selective inhibitor was isolated from the UCSC-MEL (neodysidenin), which has a unique chemical scaffold for an hLO inhibitor. Due to the unique structure of neodysidenin, steady-state inhibition kinetics were performed and its mode of inhibition against 12-hLO was determined to be competitive (Ki = 17 µM) and selective over reticulocyte 15-hLO-1 (Ki 15-hLO-1/12-hLO > 30). PMID:17826100

1-Oleoyl-2-acetylglycerol stimulates 5-lipoxygenase activity via a putative (phospho)lipid binding site within the N-terminal C2-like domain.

PubMed

Hörnig, Christina; Albert, Dana; Fischer, Lutz; Hörnig, Michael; Rådmark, Olof; Steinhilber, Dieter; Werz, Oliver

2005-07-22

5-Lipoxygenase (5-LO) catalysis is positively regulated by Ca2+ ions and phospholipids that both act via the N-terminal C2-like domain of 5-LO. Previously, we have shown that 1-oleoyl-2-acetylglycerol (OAG) functions as an agonist for human polymorphonuclear leukocytes (PMNL) in stimulating 5-LO product formation. Here we have demonstrated that OAG directly stimulates 5-LO catalysis in vitro. In the absence of Ca2+ (chelated using EDTA), OAG strongly and concentration-dependently stimulated crude 5-LO in 100,000 x g supernatants as well as purified 5-LO enzyme from PMNL. Also, the monoglyceride 1-O-oleyl-rac-glycerol and 1,2-dioctanoyl-sn-glycerol were effective, whereas various phospholipids did not stimulate 5-LO. However, in the presence of Ca2+, OAG caused no stimulation of 5-LO. Also, phospholipids or cellular membranes abolished the effects of OAG. As found previously for Ca2+, OAG renders 5-LO activity resistant against inhibition by glutathione peroxidase activity, and this effect of OAG is reversed by phospholipids. Intriguingly, a 5-LO mutant lacking tryptophan residues (Trp-13, -75, and -102) important for the binding of the 5-LO C2-like domain to phospholipids was not stimulated by OAG. We conclude that OAG directly stimulates 5-LO by acting at a phospholipid binding site located within the C2-like domain.

Universality classes of order parameters composed of many-body bound states

DOE PAGES

Tsvelik, A. M.

2016-11-28

This theoretical paper discusses microscopic models giving rise to special types of order in which conduction electrons are bound together with localized spins to create composite order parameters. It is shown that composite order is related to the formation of a spin liquid with gapped excitations carrying quantum numbers which are a fraction of those of electron. These spin liquids are special in the sense that their formation necessarily involves spin degrees of freedom of both the conduction and the localized electrons and can be characterized by nonlocal order parameters. A detailed description of such spin liquid states is presentedmore » with a special care given to a demonstration of their robustness against local perturbations preserving the Lie group symmetry and the translational invariance.« less

Comparative study of crystallization process in metallic melts using ab initio molecular dynamics simulations

NASA Astrophysics Data System (ADS)

Debela, Tekalign T.; Wang, X. D.; Cao, Q. P.; Zhang, D. X.; Jiang, J. Z.

2017-05-01

The crystallization process of liquid metals is studied using ab initio molecular dynamics simulations. The evolution of short-range order during quenching in Pb and Zn liquids is compared with body-centered cubic (bcc) Nb and V, and hexagonal closed-packed (hcp) Mg. We found that the fraction and type of the short-range order depends on the system under consideration, in which the icosahedral symmetry seems to dominate in the body-centered cubic metals. Although the local atomic structures in stable liquids are similar, liquid hcp-like Zn, bcc-like Nb and V can be deeply supercooled far below its melting point before crystallization while the supercooled temperature range in liquid Pb is limited. Further investigations into the nucleation process reveal the process of polymorph selection. In the body-centered cubic systems, the polymorph selection occurs in the supercooled state before the nucleation is initiated, while in the closed-packed systems it starts at the time of onset of crystallization. Atoms with bcc-like lattices in all studied supercooled liquids are always detected before the polymorph selection. It is also found that the bond orientational ordering is strongly correlated with the crystallization process in supercooled Zn and Pb liquids.

Impact of a new simplified disability scoring system for adult patients with localized scleroderma.

PubMed

Okiyama, Naoko; Asano, Yoshihide; Hamaguchi, Yasuhito; Jinnin, Masatoshi; Motegi, Sei-Ichiro; Koizumi, Haruka; Hasegawa, Minoru; Ishikawa, Osamu; Sato, Shinichi; Takehara, Kazuhiko; Yamamoto, Toshiyuki; Fujimoto, Manabu; Ihn, Hironobu

2018-04-01

Localized scleroderma (LoS) involves dermal but not internal inflammation and fibrosis. Cosmetic changes often impact quality of life (QOL), however, impairment of activities of daily living (ADL) in LoS patients has not been investigated. To determine what factor(s) are associated with ADL in adult patients with LoS, we performed a retrospective observational study in 177 Japanese adult LoS patients using a novel LoS disability score based on Barthel's indices of ADL: feeding, bathing, grooming, dressing, bowels, bladder, toilet use, transfers, mobility and stairs. LoS disability scores increased in proportion to the number of affected body parts but were not correlated to age and duration of illness. The presence of leg lesions significantly impaired ADL of LoS patients compared with lesions on other body parts. Patients treated with systemic medications, who tended to have multiple lesions, presented higher LoS disability scores than those without systemic treatments. Our study proposes that physicians evaluate ADL, not only QOL, in LoS patients. Our findings using LoS disability scoring indicate that multiple affected body parts and leg lesions are risk factors for ADL impairment. © 2018 Japanese Dermatological Association.

Molecular pharmacological profile of the nonredox-type 5-lipoxygenase inhibitor CJ-13,610.

PubMed

Fischer, Lutz; Steinhilber, Dieter; Werz, Oliver

2004-07-01

5-Lipoxygenase (5-LO) is a crucial enzyme in the synthesis of the bioactive leukotrienes (LTs) from arachidonic acid (AA), and inhibitors of 5-LO are thought to prevent the untowarded pathophysiological effects of LTs. In this study, we present the molecular pharmacological profile of the novel nonredox-type 5-LO inhibitor CJ-13,610 that was evaluated in various in vitro assays. In intact human polymorphonuclear leukocytes (PMNL), challenged with the Ca(2+)-ionophore A23187, CJ-13,610 potently suppressed 5-LO product formation with an IC(50)=0.07 microm. Supplementation of exogenous AA impaired the efficacy of CJ-13,610, implying a competitive mode of action. In analogy to ZM230487 and L-739.010, two closely related nonredox-type 5-LO inhibitors, CJ-13,610 up to 30 microm failed to inhibit 5-LO in cell-free assay systems under nonreducing conditions, but inclusion of peroxidase activity restored the efficacy of CJ-13,610 (IC(50)=0.3 microm). In contrast to ZM230487 and L-739.010, the potency of CJ-13,610 does not depend on the cell stimulus or the activation pathway of 5-LO. Thus, 5-LO product formation in PMNL induced by phosphorylation events was equally suppressed by CJ-13,610 as compared to Ca(2+)-mediated 5-LO activation. In transfected HeLa cells, CJ-13,610 only slightly discriminated between phosphorylatable wild-type 5-LO and a 5-LO mutant that lacks phosphorylation sites. In summary, CJ-13,610 may possess considerable potential as a potent orally active nonredox-type 5-LO inhibitor that lacks certain disadvantages of former representatives of this class of 5-LO inhibitors.

Diffractive interference optical analyzer (DiOPTER)

NASA Astrophysics Data System (ADS)

Sasikumar, Harish; Prasad, Vishnu; Pal, Parama; Varma, Manoj M.

2016-03-01

This report demonstrates a method for high-resolution refractometric measurements using, what we have termed as, a Diffractive Interference Optical Analyzer (DiOpter). The setup consists of a laser, polarizer, a transparent diffraction grating and Si-photodetectors. The sensor is based on the differential response of diffracted orders to bulk refractive index changes. In these setups, the differential read-out of the diffracted orders suppresses signal drifts and enables time-resolved determination of refractive index changes in the sample cell. A remarkable feature of this device is that under appropriate conditions, the measurement sensitivity of the sensor can be enhanced by more than two orders of magnitude due to interference between multiply reflected diffracted orders. A noise-equivalent limit of detection (LoD) of 6x10-7 RIU was achieved in glass. This work focuses on devices with integrated sample well, made on low-cost PDMS. As the detection methodology is experimentally straightforward, it can be used across a wide array of applications, ranging from detecting changes in surface adsorbates via binding reactions to estimating refractive index (and hence concentration) variations in bulk samples. An exciting prospect of this technique is the potential integration of this device to smartphones using a simple interface based on transmission mode configuration. In a transmission configuration, we were able to achieve an LoD of 4x10-4 RIU which is sufficient to explore several applications in food quality testing and related fields. We are envisioning the future of this platform as a personal handheld optical analyzer for applications ranging from environmental sensing to healthcare and quality testing of food products.

Numerical simulation analysis of four-stage mutation of solid-liquid two-phase grinding

NASA Astrophysics Data System (ADS)

Li, Junye; Liu, Yang; Hou, Jikun; Hu, Jinglei; Zhang, Hengfu; Wu, Guiling

2018-03-01

In order to explore the numerical simulation of solid-liquid two-phase abrasive grain polishing and abrupt change tube, in this paper, the fourth order abrupt change tube was selected as the research object, using the fluid mechanics software to simulate,based on the theory of solid-liquid two-phase flow dynamics, study on the mechanism of AFM micromachining a workpiece during polishing.Analysis at different inlet pressures, the dynamic pressure distribution pipe mutant fourth order abrasive flow field, turbulence intensity, discuss the influence of the inlet pressure of different abrasive flow polishing effect.

Elasticity of smectic liquid crystals with in-plane orientational order and dispiration asymmetry

NASA Astrophysics Data System (ADS)

Alageshan, Jaya Kumar; Chakrabarti, Buddhapriya; Hatwalne, Yashodhan

2017-02-01

The Nelson-Peliti formulation of the elasticity theory of isolated fluid membranes with orientational order emphasizes the interplay between geometry, topology, and thermal fluctuations. Fluid layers of lamellar liquid crystals such as smectic-C , hexatic smectics, and smectic-C* are endowed with in-plane orientational order. We extend the Nelson-Peliti formulation so as to bring these smectics within its ambit. Using the elasticity theory of smectics-C*, we show that positive and negative dispirations (topological defects in Smectic-C* liquid crystals) with strengths of equal magnitude have disparate energies—a result that is amenable to experimental tests.

Orientational Order in Liquid Crystal Complexes Based on Lanthanides

NASA Astrophysics Data System (ADS)

Dobrun, L. A.; Kovshik, A. P.; Ryumtsev, E. I.; Kalinkin, A. A.

2018-04-01

In this study, we have for the first time determined the degree of an orientational order S for a series of liquid-crystal complexes based on lanthanides (Eu+3, Gd+3, Tb+3, Dy+3) with the same ligand composition in the temperature range of existence of the nematic phase by using experimental refractometry results. We have also found an even-odd alternative S as number of protons in the ions complexing agent has consecutively increased. The obtained values of S have been compared with the corresponding degrees of order of the calamite organic liquid crystals.

Glass Forming Ability in Systems with Competing Orderings

NASA Astrophysics Data System (ADS)

Russo, John; Romano, Flavio; Tanaka, Hajime

2018-04-01

Some liquids, if cooled rapidly enough to avoid crystallization, can be frozen into a nonergodic glassy state. The tendency for a material to form a glass when quenched is called "glass-forming ability," and it is of key significance both fundamentally and for materials science applications. Here, we consider liquids with competing orderings, where an increase in the glass-forming ability is signaled by a depression of the melting temperature towards its minimum at triple or eutectic points. With simulations of two model systems where glass-forming ability can be tuned by an external parameter, we are able to interpolate between crystal-forming and glass-forming behavior. We find that the enhancement of the glass-forming ability is caused by an increase in the structural difference between liquid and crystal: stronger competition in orderings towards the melting point minimum makes a liquid structure more disordered (more complex). This increase in the liquid-crystal structure difference can be described by a single adimensional parameter, i.e., the interface energy cost scaled by the thermal energy, which we call the "thermodynamic interface penalty." Our finding may provide a general physical principle for not only controlling the glass-forming ability but also the emergence of glassy behavior of various systems with competing orderings, including orderings of structural, magnetic, electronic, charge, and dipolar origin.

Y4lO of Rhizobium sp. Strain NGR234 Is a Symbiotic Determinant Required for Symbiosome Differentiation▿

PubMed Central

Yang, Feng-Juan; Cheng, Li-Li; Zhang, Ling; Dai, Wei-Jun; Liu, Zhe; Yao, Nan; Xie, Zhi-Ping; Staehelin, Christian

2009-01-01

Type 3 (T3) effector proteins, secreted by nitrogen-fixing rhizobia with a bacterial T3 secretion system, affect the nodulation of certain host legumes. The open reading frame y4lO of Rhizobium sp. strain NGR234 encodes a protein with sequence similarities to T3 effectors from pathogenic bacteria (the YopJ effector family). Transcription studies showed that the promoter activity of y4lO depended on the transcriptional activator TtsI. Recombinant Y4lO protein expressed in Escherichia coli did not acetylate two representative mitogen-activated protein kinase kinases (human MKK6 and MKK1 from Medicago truncatula), indicating that YopJ-like proteins differ with respect to their substrate specificities. The y4lO gene was mutated in NGR234 (strain NGRΩy4lO) and in NGRΩnopL, a mutant that does not produce the T3 effector NopL (strain NGRΩnopLΩy4lO). When used as inoculants, the symbiotic properties of the mutants differed. Tephrosia vogelii, Phaseolus vulgaris cv. Yudou No. 1, and Vigna unguiculata cv. Sui Qing Dou Jiao formed pink effective nodules with NGR234 and NGRΩnopLΩy4lO. Nodules induced by NGRΩy4lO were first pink but rapidly turned greenish (ineffective nodules), indicating premature senescence. An ultrastructural analysis of the nodules induced by NGRΩy4lO revealed abnormal formation of enlarged infection droplets in ineffective nodules, whereas symbiosomes harboring a single bacteroid were frequently observed in effective nodules induced by NGR234 or NGRΩnopLΩy4lO. It is concluded that Y4lO is a symbiotic determinant involved in the differentiation of symbiosomes. Y4lO mitigated senescence-inducing effects caused by the T3 effector NopL, suggesting synergistic effects for Y4lO and NopL in nitrogen-fixing nodules. PMID:19060155

Y4lO of Rhizobium sp. strain NGR234 is a symbiotic determinant required for symbiosome differentiation.

PubMed

Yang, Feng-Juan; Cheng, Li-Li; Zhang, Ling; Dai, Wei-Jun; Liu, Zhe; Yao, Nan; Xie, Zhi-Ping; Staehelin, Christian

2009-02-01

Type 3 (T3) effector proteins, secreted by nitrogen-fixing rhizobia with a bacterial T3 secretion system, affect the nodulation of certain host legumes. The open reading frame y4lO of Rhizobium sp. strain NGR234 encodes a protein with sequence similarities to T3 effectors from pathogenic bacteria (the YopJ effector family). Transcription studies showed that the promoter activity of y4lO depended on the transcriptional activator TtsI. Recombinant Y4lO protein expressed in Escherichia coli did not acetylate two representative mitogen-activated protein kinase kinases (human MKK6 and MKK1 from Medicago truncatula), indicating that YopJ-like proteins differ with respect to their substrate specificities. The y4lO gene was mutated in NGR234 (strain NGROmegay4lO) and in NGR Omega nopL, a mutant that does not produce the T3 effector NopL (strain NGR Omega nopLOmegay4lO). When used as inoculants, the symbiotic properties of the mutants differed. Tephrosia vogelii, Phaseolus vulgaris cv. Yudou No. 1, and Vigna unguiculata cv. Sui Qing Dou Jiao formed pink effective nodules with NGR234 and NGR Omega nopL Omega y4lO. Nodules induced by NGR Omega y4lO were first pink but rapidly turned greenish (ineffective nodules), indicating premature senescence. An ultrastructural analysis of the nodules induced by NGR Omega y4lO revealed abnormal formation of enlarged infection droplets in ineffective nodules, whereas symbiosomes harboring a single bacteroid were frequently observed in effective nodules induced by NGR234 or NGR Omega nopL Omega y4lO. It is concluded that Y4lO is a symbiotic determinant involved in the differentiation of symbiosomes. Y4lO mitigated senescence-inducing effects caused by the T3 effector NopL, suggesting synergistic effects for Y4lO and NopL in nitrogen-fixing nodules.

Quick Access Rocket Exhaust Rig Testing of Coated GRCop-84 Sheets Used to Aid Coating Selection for Reusable Launch Vehicles

NASA Technical Reports Server (NTRS)

Raj, Sai V.; Robinson, Raymond C.; Ghosn, Louis J.

2005-01-01

The design of the next generation of reusable launch vehicles calls for using GRCop-84 copper alloy liners based on a composition1 invented at the NASA Glenn Research Center: Cu-8(at.%)Cr-4%Nb. Many of the properties of this alloy have been shown to be far superior to those of other conventional copper alloys, such as NARloy-Z. Despite this considerable advantage, it is expected that GRCop-84 will suffer from some type of environmental degradation depending on the type of rocket fuel utilized. In a liquid hydrogen (LH2), liquid oxygen (LO2) booster engine, copper alloys undergo repeated cycles of oxidation of the copper matrix and subsequent reduction of the copper oxide, a process termed "blanching". Blanching results in increased surface roughness and poor heat-transfer capabilities, local hot spots, decreased engine performance, and premature failure of the liner material. This environmental degradation coupled with the effects of thermomechanical stresses, creep, and high thermal gradients can distort the cooling channel severely, ultimately leading to its failure.

Destabilization of Magnetic Order in a Dilute Kitaev Spin Liquid Candidate

DOE PAGES

Lampen-Kelley, Paige; Banerjee, Arnab; Aczel, Adam A.; ...

2017-12-06

The insulating honeycomb magnet α–RuCl 3 exhibits fractionalized excitations that signal its proximity to a Kitaev quantum spin liquid state; however, at T=0, fragile long-range magnetic order arises from non-Kitaev terms in the Hamiltonian. Spin vacancies in the form of Ir 3+ substituted for Ru are found to destabilize this long-range order. Neutron diffraction and bulk characterization of Ru 1–xIr xCl 3 show that the magnetic ordering temperature is suppressed with increasing x, and evidence of zizag magnetic order is absent for x > 0.3. Inelastic neutron scattering demonstrates that the signature of fractionalized excitations is maintained over the fullmore » range of x investigated. In conclusion, the depleted lattice without magnetic order thus hosts a spin-liquid-like ground state that may indicate the relevance of Kitaev physics in the magnetically dilute limit of RuCl 3.« less

Emergence of chiral spin liquids via quantum melting of noncoplanar magnetic orders

DOE PAGES

Hickey, Ciarán; Cincio, Lukasz; Papić, Zlatko; ...

2017-09-11

Quantum spin liquids (QSLs) are highly entangled states of quantum magnets which lie beyond the Landau paradigm of classifying phases of matter via broken symmetries. A physical route to arriving at QSLs is via frustration-induced quantum melting of ordered states such as valence bond crystals or magnetic orders. Using extensive exact diagonalization (ED) and density-matrix renormalization group (DMRG)we show studies of concrete S U ( 2 ) invariant spin models on honeycomb, triangular, and square lattices, that chiral spin liquids (CSLs) emerge as descendants of triple- Q spin crystals with tetrahedral magnetic order and a large scalar spin chirality. Suchmore » ordered-to-CSL melting transitions may yield lattice realizations of effective Chern-Simons-Higgs field theories. We provides a distinct unifying perspective on the emergence of CSLs and suggests that materials with certain noncoplanar magnetic orders might provide a good starting point to search for CSLs.« less

Destabilization of Magnetic Order in a Dilute Kitaev Spin Liquid Candidate

NASA Astrophysics Data System (ADS)

Lampen-Kelley, P.; Banerjee, A.; Aczel, A. A.; Cao, H. B.; Stone, M. B.; Bridges, C. A.; Yan, J.-Q.; Nagler, S. E.; Mandrus, D.

2017-12-01

The insulating honeycomb magnet α -RuCl3 exhibits fractionalized excitations that signal its proximity to a Kitaev quantum spin liquid state; however, at T =0 , fragile long-range magnetic order arises from non-Kitaev terms in the Hamiltonian. Spin vacancies in the form of Ir3 + substituted for Ru are found to destabilize this long-range order. Neutron diffraction and bulk characterization of Ru1 -xIrxCl3 show that the magnetic ordering temperature is suppressed with increasing x , and evidence of zizag magnetic order is absent for x >0.3 . Inelastic neutron scattering demonstrates that the signature of fractionalized excitations is maintained over the full range of x investigated. The depleted lattice without magnetic order thus hosts a spin-liquid-like ground state that may indicate the relevance of Kitaev physics in the magnetically dilute limit of RuCl3 .

Emergence of chiral spin liquids via quantum melting of noncoplanar magnetic orders

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hickey, Ciarán; Cincio, Lukasz; Papić, Zlatko

Quantum spin liquids (QSLs) are highly entangled states of quantum magnets which lie beyond the Landau paradigm of classifying phases of matter via broken symmetries. A physical route to arriving at QSLs is via frustration-induced quantum melting of ordered states such as valence bond crystals or magnetic orders. Using extensive exact diagonalization (ED) and density-matrix renormalization group (DMRG)we show studies of concrete S U ( 2 ) invariant spin models on honeycomb, triangular, and square lattices, that chiral spin liquids (CSLs) emerge as descendants of triple- Q spin crystals with tetrahedral magnetic order and a large scalar spin chirality. Suchmore » ordered-to-CSL melting transitions may yield lattice realizations of effective Chern-Simons-Higgs field theories. We provides a distinct unifying perspective on the emergence of CSLs and suggests that materials with certain noncoplanar magnetic orders might provide a good starting point to search for CSLs.« less

The Landau-de Gennes approach revisited: A minimal self-consistent microscopic theory for spatially inhomogeneous nematic liquid crystals

NASA Astrophysics Data System (ADS)

Gârlea, Ioana C.; Mulder, Bela M.

2017-12-01

We design a novel microscopic mean-field theory of inhomogeneous nematic liquid crystals formulated entirely in terms of the tensor order parameter field. It combines the virtues of the Landau-de Gennes approach in allowing both the direction and magnitude of the local order to vary, with a self-consistent treatment of the local free-energy valid beyond the small order parameter limit. As a proof of principle, we apply this theory to the well-studied problem of a colloid dispersed in a nematic liquid crystal by including a tunable wall coupling term. For the two-dimensional case, we investigate the organization of the liquid crystal and the position of the point defects as a function of the strength of the coupling constant.

Indirubin core structure of glycogen synthase kinase-3 inhibitors as novel chemotype for intervention with 5-lipoxygenase.

PubMed

Pergola, Carlo; Gaboriaud-Kolar, Nicolas; Jestädt, Nadine; König, Stefanie; Kritsanida, Marina; Schaible, Anja M; Li, Haokun; Garscha, Ulrike; Weinigel, Christina; Barz, Dagmar; Albring, Kai F; Huber, Otmar; Skaltsounis, Alexios L; Werz, Oliver

2014-05-08

The enzymes 5-lipoxygenase (5-LO) and glycogen synthase kinase (GSK)-3 represent promising drug targets in inflammation. We made use of the bisindole core of indirubin, present in GSK-3 inhibitors, to innovatively target 5-LO at the ATP-binding site for the design of dual 5-LO/GSK-3 inhibitors. Evaluation of substituted indirubin derivatives led to the identification of (3Z)-6-bromo-3-[(3E)-3-hydroxyiminoindolin-2-ylidene]indolin-2-one (15) as a potent, direct, and reversible 5-LO inhibitor (IC50 = 1.5 μM), with comparable cellular effectiveness on 5-LO and GSK-3. Together, we present indirubins as novel chemotypes for the development of 5-LO inhibitors, the interference with the ATP-binding site as a novel strategy for 5-LO targeting, and dual 5-LO/GSK-3 inhibition as an unconventional and promising concept for anti-inflammatory intervention.

Liquid crystalline composites containing phyllosilicates

DOEpatents

Chaiko, David J.

2004-07-13

The present invention provides phyllosilicate-polymer compositions which are useful as liquid crystalline composites. Phyllosilicate-polymer liquid crystalline compositions of the present invention can contain a high percentage of phyllosilicate while at the same time be transparent. Because of the ordering of the particles liquid crystalline composite, liquid crystalline composites are particularly useful as barriers to gas transport.

Baclofen has opposite effects on escalation of cocaine self-administration: increased intake in rats selectively bred for high (HiS) saccharin intake and decreased intake in those selected for low (LoS) saccharin intake

PubMed Central

Holtz, Nathan A.; Carroll, Marilyn E.

2011-01-01

Rats selectively bred for high saccharin intake (HiS) self-administer more cocaine, escalate their cocaine intake during long access, and reinstate cocaine seeking at higher levels than those bred for low saccharin intake (LoS). The present study was conducted to determine if baclofen, an agonist at the GABAb receptor, has differential effects on the escalation of i.v. cocaine intake and reinstatement of cocaine-seeking in HiS and LoS rats. HiS and LoS rats self-administered cocaine during a 2-h daily short-access (ShA) phase for 3 days and then long-access (LgA) sessions for 21 days followed by a second ShA phase. One group of HiS and LoS rats received i.p. injections of 2.5 mg/kg baclofen (HiS+B and LoS+B, respectively), and other groups of HiS and LoS rats received saline (HiS+Sal and LoS+Sal) before each daily session. In a second experiment, HiS and LoS rats self-administered i.v. cocaine during 2-h sessions for 14 days followed by a 21-day extinction period. Baclofen (2.5 mg/kg, i.p.) or saline was administered before saline- or cocaine-primed reinstatement sessions. The HiS+B group escalated their cocaine self-administration and had increased cocaine infusions in the post-LgA ShA phase. The LoS+B group self-administered less cocaine throughout the entire LgA period compared to the LoS+Sal or HiS groups. Baclofen attenuated reinstatement of cocaine seeking in both the HiS and LoS rats with no phenotype differences. Baclofen had opposite effects on cocaine intake in HiS and LoS rats during escalation; HiS increased and LoS decreased intake. These results suggest that treatment effects might vary with individual differences (HiS vs. LoS) and the phase of drug-motivated behavior that is modeled. PMID:21924281

Anharmonic phonon decay in cubic GaN

NASA Astrophysics Data System (ADS)

Cuscó, R.; Domènech-Amador, N.; Novikov, S.; Foxon, C. T.; Artús, L.

2015-08-01

We present a Raman-scattering study of optical phonons in zinc-blende (cubic) GaN for temperatures ranging from 80 to 750 K. The experiments were performed on high-quality, cubic GaN films grown by molecular-beam epitaxy on GaAs (001) substrates. The observed temperature dependence of the optical phonon frequencies and linewidths is analyzed in the framework of anharmonic decay theory, and possible decay channels are discussed in the light of density-functional-theory calculations. The longitudinal-optical (LO) mode relaxation is found to occur via asymmetric decay into acoustic phonons, with an appreciable contribution of higher-order processes. The transverse-optical mode linewidth shows a weak temperature dependence and its frequency downshift is primarily determined by the lattice thermal expansion. The LO phonon lifetime is derived from the observed Raman linewidth and an excellent agreement with previous theoretical predictions is found.

HIEN-LO: An experiment for charge determination of cosmic rays of interplanetary and solar origin

NASA Technical Reports Server (NTRS)

Klecker, B.; Hovestadt, D.; Mason, G. M.; Blake, J. B.; Nicholas, J.

1988-01-01

The experiment is designed to measure the heavy ion environment at low altitude (HIEN-LO) in the energy range 0.3 to 100 MeV/nucleon. In order to cover this wide energy range a complement of three sensors is used. A large area ion drift chamber and a time-of-flight telescope are used to determine the mass and energy of the incoming cosmic rays. A third omnidirectional counter serves as a proton monitor. The analysis of mass, energy and incoming direction in combination with the directional geomagnetic cut-off allows the determination of the ionic charge of the cosmic rays. The ionic charge in this energy range is of particular interest because it provides clues to the origin of these particles and to the plasma conditions at the acceleration site. The experiment is expected to be flown in 1988/1989.

Towards Automatic Processing of Virtual City Models for Simulations

NASA Astrophysics Data System (ADS)

Piepereit, R.; Schilling, A.; Alam, N.; Wewetzer, M.; Pries, M.; Coors, V.

2016-10-01

Especially in the field of numerical simulations, such as flow and acoustic simulations, the interest in using virtual 3D models to optimize urban systems is increasing. The few instances in which simulations were already carried out in practice have been associated with an extremely high manual and therefore uneconomical effort for the processing of models. Using different ways of capturing models in Geographic Information System (GIS) and Computer Aided Engineering (CAE), increases the already very high complexity of the processing. To obtain virtual 3D models suitable for simulation, we developed a tool for automatic processing with the goal to establish ties between the world of GIS and CAE. In this paper we introduce a way to use Coons surfaces for the automatic processing of building models in LoD2, and investigate ways to simplify LoD3 models in order to reduce unnecessary information for a numerical simulation.

Enhancement of multiple-phonon resonant Raman scattering in Co-doped ZnO nanorods

NASA Astrophysics Data System (ADS)

Phan, The-Long; Vincent, Roger; Cherns, David; Dan, Nguyen Huy; Yu, Seong-Cho

2008-08-01

We have studied Raman scattering in Co-doped ZnO nanorods prepared by thermal diffusion. Experimental results show that the features of their non-resonant spectra are similar to Raman spectra from Co-doped ZnO materials investigated previously. Under resonant conditions, however, there is a strong enhancement of multiple-phonon Raman scattering processes. Longitudinal optical (LO)-phonon overtones up to eleventh order are observed. The modes become more obvious when the Co concentration diffused into ZnO nanorods goes to an appropriate value. This phenomenon is explained due to the shift of the band-gap energy and also due to the decrease in the intensity of near-band-edge luminescence. Our observation is in agreement with the prediction [J. F. Scott, Phys. Rev. B 2, 1209 (1970)] that the number of LO-phonon lines in ZnO is higher than that observed for CdS.

Vapor-Deposited Glasses with Long-Range Columnar Liquid Crystalline Order

DOE PAGES

Gujral, Ankit; Gomez, Jaritza; Ruan, Shigang; ...

2017-10-04

Anisotropic molecular packing, particularly in highly ordered liquid crystalline arrangements, has the potential for optimizing performance in organic electronic and optoelectronic applications. Here we show that physical vapor deposition can be used to prepare highly organized glassy solids of discotic liquid crystalline systems. Using grazing incidence X-ray scattering, atomic force microscopy, and UV–vis spectroscopy, we compare three systems: a rectangular columnar liquid crystal, a hexagonal columnar liquid crystal, and a nonmesogen. The packing motifs accessible by vapor deposition are highly organized for the liquid crystalline systems with columns propagating either in-plane or out-of-plane depending upon the substrate temperature during deposition.more » As a result, the structures formed at a given substrate temperature can be understood as resulting from partial equilibration toward the structure of the equilibrium liquid crystal surface during the deposition process.« less

Vapor-Deposited Glasses with Long-Range Columnar Liquid Crystalline Order

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gujral, Ankit; Gomez, Jaritza; Ruan, Shigang

Anisotropic molecular packing, particularly in highly ordered liquid crystalline arrangements, has the potential for optimizing performance in organic electronic and optoelectronic applications. Here we show that physical vapor deposition can be used to prepare highly organized glassy solids of discotic liquid crystalline systems. Using grazing incidence X-ray scattering, atomic force microscopy, and UV–vis spectroscopy, we compare three systems: a rectangular columnar liquid crystal, a hexagonal columnar liquid crystal, and a nonmesogen. The packing motifs accessible by vapor deposition are highly organized for the liquid crystalline systems with columns propagating either in-plane or out-of-plane depending upon the substrate temperature during deposition.more » As a result, the structures formed at a given substrate temperature can be understood as resulting from partial equilibration toward the structure of the equilibrium liquid crystal surface during the deposition process.« less

Solution-limited time stepping method and numerical simulation of single-element rocket engine combustor

NASA Astrophysics Data System (ADS)

Lian, Chenzhou

The focus of the research is to gain a better understanding of the mixing and combustion of propellants in a confined single element rocket engine combustor. The approach taken is to use the unsteady computational simulations of both liquid and gaseous oxygen reacting with gaseous hydrogen to study the effects of transient processes, recirculation regions and density variations under supercritical conditions. The physics of combustion involve intimate coupling between fluid dynamics, chemical kinetics and intense energy release and take place over an exceptionally wide range of scales. In the face of these monumental challenges, it remains the engineer's task to find acceptable simulation approach and reliable CFD algorithm for combustion simulations. To provide the computational robustness to allow detailed analyses of such complex problems, we start by investigating a method for enhancing the reliability of implicit computational algorithms and decreasing their sensitivity to initial conditions without adversely impacting their efficiency. Efficient convergence is maintained by specifying a large global CFL number while reliability is improved by limiting the local CFL number such that the solution change in any cell is less than a specified tolerance. The magnitude of the solution change is estimated from the calculated residual in a manner that requires negligible computational time. The method precludes unphysical excursions in Newton-like iterations in highly non-linear regions where Jacobians are changing rapidly as well as non-physical results during the computation. The method is tested against a series of problems to identify its characteristics and to verify the approach. The results reveal a substantial improvement in convergence reliability of implicit CFD applications that enables computations starting from simple initial conditions. The method is applied in the unsteady combustion simulations and allows long time running of the code without user intervention. The initial transient leading to stationary conditions in unsteady combustion simulations is investigated by considering flow establishment in model combustors. The duration of the transient is shown to be dependent on the characteristic turn-over time for recirculation zones and the time for the chamber pressure to reach steady conditions. Representative comparisons of the time-averaged, stationary results with experiment are presented to document the computations. The flow dynamics and combustion for two sizes of chamber diameters and two different wall thermal boundary conditions are investigated to assess the role of the recirculation regions on the mixing/combustion process in rocket engine combustors. Results are presented in terms of both instantaneous and time-averaged solutions. As a precursor to liquid oxygen/gaseous hydrogen (LO2/GH 2) combustion simulations, the evolution of a liquid nitrogen (LN 2) jet initially at a subcritical temperature and injected into a supercritical environment is first investigated and the results are validated against experimental data. Unsteady simulations of non-reacting LO2/GH 2 are then performed for a single element shear coaxial injector. These cold flow calculations are then extended to reacting LO2/GH 2 flows to demonstrate the capability of the numerical procedure for high-density-gradient supercritical reacting flows.

The novel metallic states of the cuprates: Topological Fermi liquids and strange metals

NASA Astrophysics Data System (ADS)

Sachdev, Subir; Chowdhury, Debanjan

2016-12-01

We review ideas on the nature of the metallic states of the hole-doped cuprate high temperature superconductors, with an emphasis on the connections between the Luttinger theorem for the size of the Fermi surface, topological quantum field theories (TQFTs), and critical theories involving changes in the size of the Fermi surface. We begin with the derivation of the Luttinger theorem for a Fermi liquid, using momentum balance during a process of flux insertion in a lattice electronic model with toroidal boundary conditions. We then review the TQFT of the ℤ spin liquid, and demonstrate its compatibility with the toroidal momentum balance argument. This discussion leads naturally to a simple construction of "topological" Fermi liquid states: the fractionalized Fermi liquid (FL*) and the algebraic charge liquid (ACL). We present arguments for a description of the pseudogap metal of the cuprates using ℤ-FL* or ℤ-ACL states with Ising-nematic order. These pseudogap metal states are also described as Higgs phases of a SU(2) gauge theory. The Higgs field represents local antiferromagnetism, but the Higgs-condensed phase does not have long-range antiferromagnetic order: the magnitude of the Higgs field determines the pseudogap, the reconstruction of the Fermi surface, and the Ising-nematic order. Finally, we discuss the route to the large Fermi surface Fermi liquid via the critical point where the Higgs condensate and Ising nematic order vanish, and the application of Higgs criticality to the strange metal.

A Generic Authentication LoA Derivation Model

NASA Astrophysics Data System (ADS)

Yao, Li; Zhang, Ning

One way of achieving a more fine-grained access control is to link an authentication level of assurance (LoA) derived from a requester’s authentication instance to the authorisation decision made to the requester. To realise this vision, there is a need for designing a LoA derivation model that supports the use and quantification of multiple LoA-effecting attributes, and analyse their composite effect on a given authentication instance. This paper reports the design of such a model, namely a generic LoA derivation model (GEA- LoADM). GEA-LoADM takes into account of multiple authentication attributes along with their relationships, abstracts the composite effect by the multiple attributes into a generic value, authentication LoA, and provides algorithms for the run-time derivation of LoA. The algorithms are tailored to reflect the relationships among the attributes involved in an authentication instance. The model has a number of valuable properties, including flexibility and extensibility; it can be applied to different application contexts and support easy addition of new attributes and removal of obsolete ones.

Solvent-free directed patterning of a highly ordered liquid crystalline organic semiconductor via template-assisted self-assembly for organic transistors.

PubMed

Kim, Aryeon; Jang, Kwang-Suk; Kim, Jinsoo; Won, Jong Chan; Yi, Mi Hye; Kim, Hanim; Yoon, Dong Ki; Shin, Tae Joo; Lee, Myong-Hoon; Ka, Jae-Won; Kim, Yun Ho

2013-11-20

Highly ordered organic semiconductor micropatterns of the liquid-crystalline small molecule 2,7-didecylbenzothienobenzothiophene (C10 -BTBT) are fabricated using a simple method based on template-assisted self-assembly (TASA). The liquid crystallinity of C10 -BTBT allows solvent-free fabrication of high-performance printed organic field-effect transistors (OFETs). © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Theoretical performance of some rocket propellants containing hydrogen, nitrogen, and oxygen

NASA Technical Reports Server (NTRS)

Miller, Riley O; Ordin, Paul M

1948-01-01

Theoretical performance data including nozzle-exit temperature, specific impulse, volume specific impulse and composition, temperature, and mean molecular weight of reaction products based on frozen equilibrium and isentropic expansion are presented for 13 propellant combinations at reaction pressure of 300 pounds per square inch absolute and expansion ratio of 20.4. On basis of maximum specific impulse alone, five fuels had the following order for any given oxidant: liquid hydrogen, hydrazine, liquid ammonia, and either hydrazine hydrate or hydroxylamine. Three oxidants with a given fuel had the following order: liquid ozone, liquid oxygen, and 100-percent hydrogen peroxide.

Background characterization of an ultra-low background liquid scintillation counter

DOE PAGES

Erchinger, J. L.; Orrell, John L.; Aalseth, C. E.; ...

2017-01-26

The Ultra-Low Background Liquid Scintillation Counter developed by Pacific Northwest National Laboratory will expand the application of liquid scintillation counting by enabling lower detection limits and smaller sample volumes. By reducing the overall count rate of the background environment approximately 2 orders of magnitude below that of commercially available systems, backgrounds on the order of tens of counts per day over an energy range of ~3–3600 keV can be realized. Finally, initial test results of the ULB LSC show promising results for ultra-low background detection with liquid scintillation counting.

Life Orientation as Experienced by Learners: A Qualitative Study in North-West Province

ERIC Educational Resources Information Center

Jacobs, Anne

2011-01-01

The learning area Life Orientation (LO) is aimed at educating healthy, responsible young people who are able to live productive lives in the new South African democracy. Effectiveness in this learning area has not yet been proved and there is evidence of some problems in attaining this ideal. In order to give voice to learners, in terms of their…

Nonculturability Might Underestimate the Occurrence of Campylobacter in Broiler Litter.

PubMed

Kassem, Issmat I; Helmy, Yosra A; Kathayat, Dipak; Candelero-Rueda, Rosario A; Kumar, Anand; Deblais, Loic; Huang, Huang-Chi; Sahin, Orhan; Zhang, Qijing; Rajashekara, Gireesh

2017-08-01

We investigated the contribution of litter to the occurrence of Campylobacter on three broiler farms, which were known to have low (LO) and high (HI-A and HI-B) Campylobacter prevalence. For this purpose, we collected litter samples (n = 288) during and after two rearing cycles from each farm. We evaluated the occurrence of Campylobacter (using selective enrichment and quantitative real-time polymerase chain reaction [q-PCR] analysis) in the litter samples as well as the litter's pH and moisture content. Ceca from each flock (n = 144) were harvested at slaughter age and used to quantify Campylobacter colony-forming units (CFUs). Campylobacter was only retrieved from 7 litter samples that were collected from HI-A and HI-B during the growing period, but no Campylobacter was isolated from LO farms. The q-PCR analysis detected Campylobacter in pooled litter samples from all three farms. However, in litter collected during the same rotation, Campylobacter levels were significantly higher (p < 0.05) in HI-A and HI-B litter samples in comparison to those in LO. Cecal samples from HI-A and HI-B yielded relatively high numbers of Campylobacter CFUs, which were undetectable in LO samples. Litter's pH and moisture did not affect the overall occurrence of Campylobacter in litter and ceca on any of the farms. Our data suggest that Campylobacter was generally more abundant in litter that was collected from farms with highly colonized flocks. Therefore, better approaches for assessing the occurrence of Campylobacter in litter might be warranted in order to reduce the dissemination of these pathogens on and off poultry farms.

INTENSITY AND GENERALIZATION OF TREADMILL-SLIP TRAINING: HIGH OR LOW; PROGRESSIVELY-INCREASE OR -DECREASE?

PubMed Central

Liu, Xuan; Bhatt, Tanvi; Pai, Yi-Chung (Clive)

2015-01-01

Very little is known how training intensity interacts with the generalization from treadmill-slip to overground slip. The purposes of this study were to determine whether treadmill-slip training improved center-of-mass stability, more so in the reactive than in the proactive control of stability, with high intensity (HI with a trial-to-trial-consistent acceleration of 12 m/s2) better than low intensity training (LO with a consistent acceleration of 6 m/s2), and progressively-increasing intensity (INCR with a block-to-block acceleration varied from 6 to 12 m/s2) better than progressively-decreasing intensity training (DECR with an acceleration varied from 12 to 6 m/s2) in such generalization. Thirty-six young subjects evenly assigned to one of four (HI, LO, INCR, DECR) groups underwent 24 treadmill-slips before their generalization test trial with a novel slip during overground walking. The controls (CTRL, n=9) from existing data only experienced the same novel overground slip without treadmill training but under otherwise identical condition. The results showed that treadmill-slip training did improved balance control on overground slip with a greater impact on subjects’ reactive (44.3%) than proactive control of stability (27.1%) in comparison to the CTRL. HI yielded stronger generalization than LO, while INCR was only marginally better than DECR. Finally, the group means of these four displayed a clear ascending order from CTRL, LO, DECR, INCR, to HI. The results suggested that higher training intensity on treadmill led to a better generalization, while a progressively-increase in intensity had advantage over the progressively-decrease or the low training strategy. (243 words) PMID:26159058

Anomalous phase behavior of first-order fluid-liquid phase transition in phosphorus

NASA Astrophysics Data System (ADS)

Zhao, G.; Wang, H.; Hu, D. M.; Ding, M. C.; Zhao, X. G.; Yan, J. L.

2017-11-01

Although the existence of liquid-liquid phase transition has become more and more convincing, whether it will terminate at a critical point and what is the order parameter are still open. To explore these questions, we revisit the fluid-liquid phase transition (FLPT) in phosphorus (P) and study its phase behavior by performing extensive first-principles molecular dynamics simulations. The FLPT observed in experiments is well reproduced, and a fluid-liquid critical point (FLCP) at T = 3000 ˜ 3500 K, P = 1.5-2.0 Kbar is found. With decreasing temperature from the FLCP along the transition line, the density difference (Δρ) between two coexisting phases first increases from zero and then anomalously decreases; however, the entropy difference (ΔS) continuously increases from zero. These features suggest that an order parameter containing contributions from both the density and the entropy is needed to describe the FLPT in P, and at least at low temperatures, the entropy, instead of the density, governs the FLPT.

Induced liquid-crystalline ordering in solutions of stiff and flexible amphiphilic macromolecules: Effect of mixture composition

DOE Office of Scientific and Technical Information (OSTI.GOV)

Glagolev, Mikhail K.; Vasilevskaya, Valentina V., E-mail: vvvas@polly.phys.msu.ru; Khokhlov, Alexei R.

Impact of mixture composition on self-organization in concentrated solutions of stiff helical and flexible macromolecules was studied by means of molecular dynamics simulation. The macromolecules were composed of identical amphiphilic monomer units but a fraction f of macromolecules had stiff helical backbones and the remaining chains were flexible. In poor solvents the compacted flexible macromolecules coexist with bundles or filament clusters from few intertwined stiff helical macromolecules. The increase of relative content f of helical macromolecules leads to increase of the length of helical clusters, to alignment of clusters with each other, and then to liquid-crystalline-like ordering along a singlemore » direction. The formation of filament clusters causes segregation of helical and flexible macromolecules and the alignment of the filaments induces effective liquid-like ordering of flexible macromolecules. A visual analysis and calculation of order parameter relaying the anisotropy of diffraction allow concluding that transition from disordered to liquid-crystalline state proceeds sharply at relatively low content of stiff components.« less

Discovering local order parameters in liquid water using machine learning

NASA Astrophysics Data System (ADS)

Soto, Adrian; Lu, Deyu; Yoo, Shinjae; Fernandez-Serra, Marivi

The local arrangement of water molecules in liquid phase is still being discussed and questioned. The prevailing view is that water is composed of a mixture of two structurally different liquids. One of the main challenges has been to find order parameters that are able to discriminate the complex structures of these distinct molecular environments. Several local order parameters have been proposed and studied in all sorts of atomistic simulations of liquid water but, to date, none has been able to capture the predicted dual character. This presents an ideal problem to treat with methods capable of unveiling information from complex data. In this talk we will discuss how local order parameters can be constructed from molecular dynamics trajectories by using machine learning and other related techniques. Work was partially supported by DOE Award No. DE-FG02-09ER16052, by DOE Early Career Award No. DE-SC0003871, by BNL LDRD 16-039 project and BNL Contract No. DE-SC0012704.

Charge ordering and scattering pre-peaks in ionic liquids and alcohols.

PubMed

Perera, Aurélien

2017-01-04

The structural properties of ionic liquids and alcohols are viewed under the charge ordering process as a common basis to explain the peculiarity of their radiation scattering properties, namely the presence, or absence, of a scattering pre-peak. Through the analysis of models, it is shown that the presence, or absence, of a radiation scattering pre-peak is principally related to the symmetry breaking, or not, of the global charge order, induced by the peculiarities of the molecular shapes. This symmetry breaking is achieved, in practice, by the emergence of specific types of clusters, which manifests how the global charge order has changed into a local form. Various atom-atom correlations witness the symmetry breaking induced by this re organization, and this is manifested into a pre-peak in the structure factor. This approach explains why associated liquids such as water do not show a scattering pre-peak. It also explains under which conditions core-soft models can mimic associating liquids.

Liquidity crises on different time scales

NASA Astrophysics Data System (ADS)

Corradi, Francesco; Zaccaria, Andrea; Pietronero, Luciano

2015-12-01

We present an empirical analysis of the microstructure of financial markets and, in particular, of the static and dynamic properties of liquidity. We find that on relatively large time scales (15 min) large price fluctuations are connected to the failure of the subtle mechanism of compensation between the flows of market and limit orders: in other words, the missed revelation of the latent order book breaks the dynamical equilibrium between the flows, triggering the large price jumps. On smaller time scales (30 s), instead, the static depletion of the limit order book is an indicator of an intrinsic fragility of the system, which is related to a strongly nonlinear enhancement of the response. In order to quantify this phenomenon we introduce a measure of the liquidity imbalance present in the book and we show that it is correlated to both the sign and the magnitude of the next price movement. These findings provide a quantitative definition of the effective liquidity, which proves to be strongly dependent on the considered time scales.

Liquidity crises on different time scales.

PubMed

Corradi, Francesco; Zaccaria, Andrea; Pietronero, Luciano

2015-12-01

We present an empirical analysis of the microstructure of financial markets and, in particular, of the static and dynamic properties of liquidity. We find that on relatively large time scales (15 min) large price fluctuations are connected to the failure of the subtle mechanism of compensation between the flows of market and limit orders: in other words, the missed revelation of the latent order book breaks the dynamical equilibrium between the flows, triggering the large price jumps. On smaller time scales (30 s), instead, the static depletion of the limit order book is an indicator of an intrinsic fragility of the system, which is related to a strongly nonlinear enhancement of the response. In order to quantify this phenomenon we introduce a measure of the liquidity imbalance present in the book and we show that it is correlated to both the sign and the magnitude of the next price movement. These findings provide a quantitative definition of the effective liquidity, which proves to be strongly dependent on the considered time scales.

40 CFR 1065.610 - Duty cycle generation.

Code of Federal Regulations, 2014 CFR

2014-07-01

.... Denote this value as n lo. Take n lo to be warm idle speed if all power points at speeds below the... n lo to calculate reference values for A, B, or C speeds as follows: ER15SE11.030 Example: n lo...

Pressure dependence of the optical phonon frequencies and the transverse effective charge in AlSb

NASA Astrophysics Data System (ADS)

Ves, S.; Strössner, K.; Cardona, M.

1986-02-01

The first order Raman scattering by TO and LO phonons has been measured in AlSb under hydrostatic' pressures up to its phase transition. The Raman frequencies increase nearly linear while the transverse effective charge e ∗T are compared with estimates based on pseudopotential and on LCAO calculation. In order to obtain from the measured pressure dependence the corresponding volume coefficients the bulk modulus B O and its pressure derivative BOˌ = {dBO}/{dP} was measured by energy-dispersive X-ray diffraction (B O = 55.1 GPa and BOˌ = 4.55 ).

Modeling liquid crystal polymeric devices

NASA Astrophysics Data System (ADS)

Gimenez Pinto, Vianney Karina

The main focus of this work is the theoretical and numerical study of materials that combine liquid crystal and polymer. Liquid crystal elastomers are polymeric materials that exhibit both the ordered properties of the liquid crystals and the elastic properties of rubbers. Changing the order of the liquid crystal molecules within the polymer network can induce shape change. These materials are very valuable for applications such as actuators, sensors, artificial muscles, haptic displays, etc. In this work we apply finite element elastodynamics simulations to study the temperature induced shape deformation in nematic elastomers with complex director microstructure. In another topic, we propose a novel numerical method to model the director dynamics and microstructural evolution of three dimensional nematic and cholesteric liquid crystals. Numerical studies presented in this work are in agreement with experimental observations and provide insight into the design of application devices.

40 CFR 1065.610 - Duty cycle generation.

Code of Federal Regulations, 2011 CFR

2011-07-01

... maximum power at which 50% of maximum power occurs. Denote this value as n lo. Take n lo to be warm idle... representative engine speed, whichever is lower. Use n hi and n lo to calculate reference values for A, B, or C speeds as follows: f nrefA = 0.25 · (n hi − n lo) + n lo Eq. 1065.610-4 f nrefB = 0.50 · (n hi − nnlo...

Robust Exploration and Commercial Missions to the Moon Using LANTR Propulsion and In-Situ Propellants Derived from Lunar Polar Ice (LPI) Deposits

NASA Technical Reports Server (NTRS)

Borowski, Stanley K.; Ryan, Stephen W.; Burke, Laura M.; McCurdy, David R.; Fittje, James E.; Joyner, Claude R.

2017-01-01

The nuclear thermal rocket (NTR) has frequently been identified as a key space asset required for the human exploration of Mars. This proven technology can also provide the affordable access through cislunar space necessary for commercial development and sustained human presence on the Moon. It is a demonstrated technology capable of generating both high thrust and high specific impulse (Isp 900 s) twice that of todays best chemical rockets. Nuclear lunar transfer vehicles consisting of a propulsion stage using three approx.16.5 klbf "Small Nuclear Rocket Engines (SNREs)", an in-line propellant tank, plus the payload can enable a variety of reusable lunar missions. These include cargo delivery and crewed lunar landing missions. Even weeklong "tourism" missions carrying passengers into lunar orbit for a day of sightseeing and picture taking are possible. The NTR can play an important role in the next phase of lunar exploration and development by providing a robust in-space lunar transportation system (LTS) that can allow initial outposts to evolve into settlements supported by a variety of commercial activities such as in-situ propellant production used to supply strategically located propellant depots and transportation nodes. The processing of LPI deposits (estimated to be approx. 2 billion metric tons) for propellant production - specifically liquid oxygen (LO2) and hydrogen (LH2) can significantly reduce the launch mass requirements from Earth and can enable reusable, surface-based lunar landing vehicles (LLVs) using LO2/LH2 chemical rocket engines. Afterwards, LO2/LH2 propellant depots can be established in lunar polar and equatorial orbits to supply the LTS. At this point a modified version of the conventional NTR called the LO2-augmented NTR, or LANTR would be introduced into the LTS allowing bipropellant operation and leveraging the mission benefits of refueling with lunar-derived propellants (LDPs) for Earth return. The bipropellant LANTR engine utilizes the large divergent section of its nozzle as an afterburner into which oxygen is injected and supersonically combusted with nuclear preheated hydrogen emerging from the engines choked sonic throat essentially scramjet propulsion in reverse. By varying the oxygen-to-hydrogen mixture ratio, LANTR engines can operate over a range of thrust and Isp values while the reactor core power level remains relatively constant. A LANTR-based LTS offers unique mission capabilities including short transit time crewed cargo transports. Even a commuter shuttle service may be possible allowing one-way trip times to and from the Moon on the order of 36 hours or less. If only 1 of the postulated water ice trapped in deep shadowed craters at the lunar poles were available for use in lunar orbit, such a supply could support daily commuter flights to the Moon for many thousands of years! The proposed paper outlines an evolutionary mission architecture and examines a variety of mission types and transfer vehicle designs, along with the increasing demands on LDP production as mission complexity and delta V requirements increase. A comparison of vehicle features and engine operating characteristics are also provided together with a discussion of the propellant production and mining requirements, and issues, associated with using LPI as the source material.

Biasable, Balanced, Fundamental Submillimeter Monolithic Membrane Mixer

NASA Technical Reports Server (NTRS)

Siegel, Peter; Schlecht, Erich; Mehdi, Imran; Gill, John; Velebir, James; Tsang, Raymond; Dengler, Robert; Lin, Robert

2010-01-01

This device is a biasable, submillimeter-wave, balanced mixer fabricated using JPL s monolithic membrane process a simplified version of planar membrane technology. The primary target application is instrumentation used for analysis of atmospheric constituents, pressure, temperature, winds, and other physical and chemical properties of the atmospheres of planets and comets. Other applications include high-sensitivity gas detection and analysis. This innovation uses a balanced configuration of two diodes allowing the radio frequency (RF) signal and local oscillator (LO) inputs to be separated. This removes the need for external diplexers that are inherently narrowband, bulky, and require mechanical tuning to change frequency. Additionally, this mixer uses DC bias-ability to improve its performance and versatility. In order to solve problems relating to circuit size, the GaAs membrane process was created. As much of the circuitry as possible is fabricated on-chip, making the circuit monolithic. The remainder of the circuitry is precision-machined into a waveguide block that holds the GaAs circuit. The most critical alignments are performed using micron-scale semiconductor technology, enabling wide bandwidth and high operating frequencies. The balanced mixer gets superior performance with less than 2 mW of LO power. This can be provided by a simple two-stage multiplier chain following an amplifier at around 90 GHz. Further, the diodes are arranged so that they can be biased. Biasing pushes the diodes closer to their switching voltage, so that less LO power is required to switch the diodes on and off. In the photo, the diodes are at the right end of the circuit. The LO comes from the waveguide at the right into a reduced-height section containing the diodes. Because the diodes are in series to the LO signal, they are both turned on and off simultaneously once per LO cycle. Conversely, the RF signal is picked up from the RF waveguide by the probe at the left, and flows rightward to the diodes. Because the RF is in a quasi- TEM (suspended, microstrip-like) mode, it impinges on the diodes in an anti-parallel mode that does not couple to the waveguide mode. This isolates the LO and RF signals. This operation is similar to a cross-bar mixer used at low frequencies, except the RF signal enters through the back-short end of the waveguide rather than through the side. The RF probe also conveys the down-converted intermediate frequency (IF) signal out to an off-chip circuit board through a simple LC low-pass filter to the left as indicated. The bias is brought to the diodes through a bypass capacitor at the top.

Detection of bottled liquid explosives by near infrared

NASA Astrophysics Data System (ADS)

Itozaki, Hide; Miyamura, Ryu; Sato-Akaba, Hideo

2012-10-01

Bottled liquids are limited to be brought in the airplane, because liquid explosives have been used in some terrorist attaches recently. A bottled liquid scanner is expected to be developed. Liquid scanner using near infrared technologies is being developed by us. Many spectrum of liquids have been collected and analyzed by chemometorics in order to separate safe beverage to explosive and dangerous liquids. This bottled liquid scanner had feasibility tests in some international airport in Japan and obtained good review from security people in the airport.

Structural analysis of zwitterionic liquids vs. homologous ionic liquids

NASA Astrophysics Data System (ADS)

Wu, Boning; Kuroda, Kosuke; Takahashi, Kenji; Castner, Edward W.

2018-05-01

Zwitterionic liquids (Zw-ILs) have been developed that are homologous to monovalent ionic liquids (ILs) and show great promise for controlled dissolution of cellulosic biomass. Using both high energy X-ray scattering and atomistic molecular simulations, this article compares the bulk liquid structural properties for novel Zw-ILs with their homologous ILs. It is shown that the significant localization of the charges on Zw-ILs leads to charge ordering similar to that observed for conventional ionic liquids with monovalent anions and cations. A low-intensity first sharp diffraction peak in the liquid structure factor S(q) is observed for both the Zw-IL and the IL. This is unexpected since both the Zw-IL and IL have a 2-(2-methoxyethoxy)ethyl (diether) functional group on the cationic imidazolium ring and ether functional groups are known to suppress this peak. Detailed analyses show that this intermediate range order in the liquid structure arises for slightly different reasons in the Zw-IL vs. the IL. For the Zw-IL, the ether tails in the liquid are shown to aggregate into nanoscale domains.

Low-G fluid transfer technology study

NASA Technical Reports Server (NTRS)

Stark, J. A.

1976-01-01

Technology gaps and system characteristics critical to cryogenic and noncryogenic in-orbit fluid transfer were identified. Four different supply systems were conceptually designed as space shuttle payloads. These were; (1) space tug supply - LH2, LO2, N2H4, He - linear acceleration for liquid acquisition with supply module and tug separated from shuttle, (2) tug supply using orbiter drag, (3) orbiter supply - N2O4,MMH,He, H2,O2 - surface tension screens, (4) multiple receivers supply 0 solar electric propulsion stage, Hg, diaphragm - HEAO B, HEe, paddle fluid rotation-satellite control section, N2H4, screens. It was found that screens had the best overall potential for low weight and simplicity, however, thermal problems with cryogenics still need final resolution.

Cryo Tank Fill at Pad 39B

NASA Image and Video Library

2017-09-26

A large plume of mist or vapor is visible as a Praxair truck slowly transfers its load of liquid oxygen, or LO2, into a giant storage sphere at the northwest corner of Launch Pad 39B at NASA's Kennedy Space Center in Florida. The sphere will gradually be chilled down from normal temperature to about negative 298 degrees Fahrenheit, during the first major integrated operation to prepare for the launch of the agency's Orion spacecraft atop the Space Launch System (SLS) rocket. The Ground Systems Development and Operations Program is overseeing upgrades and modifications to pad B to support the launch of the SLS and Orion spacecraft for Exploration Mission-1, deep space missions and NASA’s journey to Mars.

Field-controlled structures in ferromagnetic cholesteric liquid crystals.

PubMed

Medle Rupnik, Peter; Lisjak, Darja; Čopič, Martin; Čopar, Simon; Mertelj, Alenka

2017-10-01

One of the advantages of anisotropic soft materials is that their structures and, consequently, their properties can be controlled by moderate external fields. Whereas the control of materials with uniform orientational order is straightforward, manipulation of systems with complex orientational order is challenging. We show that a variety of structures of an interesting liquid material, which combine chiral orientational order with ferromagnetic one, can be controlled by a combination of small magnetic and electric fields. In the suspensions of magnetic nanoplatelets in chiral nematic liquid crystals, the platelet's magnetic moments orient along the orientation of the liquid crystal and, consequently, the material exhibits linear response to small magnetic fields. In the absence of external fields, orientations of the liquid crystal and magnetization have wound structure, which can be either homogeneously helical, disordered, or ordered in complex patterns, depending on the boundary condition at the surfaces and the history of the sample. We demonstrate that by using different combinations of small magnetic and electric fields, it is possible to control reversibly the formation of the structures in a layer of the material. In such a way, different periodic structures can be explored and some of them may be suitable for photonic applications. The material is also a convenient model system to study chiral magnetic structures, because it is a unique liquid analog of a solid helimagnet.

Robust Exploration and Commercial Missions to the Moon Using LANTR Propulsion and Lunar Liquid Oxygen Derived from FeO-Rich Pyroclastic Deposits

NASA Technical Reports Server (NTRS)

Borowski, Stanley K.; Ryan, Stephen W.; Burke, Laura M.; McCurdy, David R.; Fittje, James E.; Joyner, Claude R.

2017-01-01

The nuclear thermal rocket (NTR) has frequently been identified as a key space asset required for the human exploration of Mars. This proven technology can also provide the affordable access through cislunar space necessary for commercial development and sustained human presence on the Moon. It is a demonstrated technology capable of generating both high thrust and high specific impulse (Isp approx.900 s) twice that of todays best chemical rockets. Nuclear lunar transfer vehicles consisting of a propulsion stage using three approx.16.5 klbf Small Nuclear Rocket Engines (SNREs), an in-line propellant tank, plus the payload can enable a variety of reusable lunar missions. These include cargo delivery and crewed lunar landing missions. Even weeklong tourism missions carrying passengers into lunar orbit for a day of sightseeing and picture taking are possible. The NTR can play an important role in the next phase of lunar exploration and development by providing a robust in-space lunar transportation system (LTS) that can allow initial outposts to evolve into settlements supported by a variety of commercial activities such as in-situ propellant production used to supply strategically located propellant depots and transportation nodes. The use of lunar liquid oxygen (LLO2) derived from iron oxide (FeO)-rich volcanic glass beads, found in numerous pyroclastic deposits on the Moon, can significantly reduce the launch mass requirements from Earth by enabling reusable, surface-based lunar landing vehicles (LLVs) using liquid oxygen/hydrogen (LO2/H2) chemical rocket engines. Afterwards, a LO2/H2 propellant depot can be established in lunar equatorial orbit to supply the LTS. At this point a modified version of the conventional NTR called the LOX-augmented NTR, or LANTR is introduced into the LTS allowing bipropellant operation and leveraging the mission benefits of refueling with lunar-derived propellants for Earth return. The bipropellant LANTR engine utilizes the large divergent section of its nozzle as an afterburner into which oxygen is injected and supersonically combusted with nuclear preheated hydrogen emerging from the engines choked sonic throat - essentially scramjet propulsion in reverse. By varying the oxygen-to-hydrogen mixture ratio, LANTR engines can operate over a range of thrust and Isp values while the reactor core power level remains relatively constant. A LANTR-based LTS offers unique mission capabilities including short transit time crewed cargo transports. Even a commuter shuttle service may be possible allowing one-way trip times to and from the Moon on the order of 36 hours or less. If only 1 of the extracted LLO2 propellant from identified resource sites were available for use in lunar orbit, such a supply could support daily commuter flights to the Moon for many thousands of years! The proposed paper outlines an evolutionary architecture and examines a variety of mission types and transfer vehicle designs, along with the increasing demands on LLO2 production as mission complexity and (Delta)V requirements increase. A comparison of vehicle features and engine operating characteristics, for both NTR and LANTR engines, is also provided along with a discussion of the propellant production and mining requirements associated with using FeO-rich volcanic glass as source material.

Hyperforin is a novel type of 5-lipoxygenase inhibitor with high efficacy in vivo.

PubMed

Feisst, Christian; Pergola, Carlo; Rakonjac, Marija; Rossi, Antonietta; Koeberle, Andreas; Dodt, Gabriele; Hoffmann, Marika; Hoernig, Christina; Fischer, Lutz; Steinhilber, Dieter; Franke, Lutz; Schneider, Gisbert; Rådmark, Olof; Sautebin, Lidia; Werz, Oliver

2009-08-01

We previously showed that, in vitro, hyperforin from St. John's wort (Hypericum perforatum) inhibits 5-lipoxygenase (5-LO), the key enzyme in leukotriene biosynthesis. Here, we demonstrate that hyperforin possesses a novel and unique molecular pharmacological profile as a 5-LO inhibitor with remarkable efficacy in vivo. Hyperforin (4 mg/kg, i.p.) significantly suppressed leukotriene B(4) formation in pleural exudates of carrageenan-treated rats associated with potent anti-inflammatory effectiveness. Inhibition of 5-LO by hyperforin, but not by the iron-ligand type 5-LO inhibitor BWA4C or the nonredox-type inhibitor ZM230487, was abolished in the presence of phosphatidylcholine and strongly reduced by mutation (W13A-W75A-W102A) of the 5-LO C2-like domain. Moreover, hyperforin impaired the interaction of 5-LO with coactosin-like protein and abrogated 5-LO nuclear membrane translocation in ionomycin-stimulated neutrophils, processes that are typically mediated via the regulatory 5-LO C2-like domain. Together, hyperforin is a novel type of 5-LO inhibitor apparently acting by interference with the C2-like domain, with high effectiveness in vivo.

Multivariate Patterns in the Human Object-Processing Pathway Reveal a Shift from Retinotopic to Shape Curvature Representations in Lateral Occipital Areas, LO-1 and LO-2.

PubMed

Vernon, Richard J W; Gouws, André D; Lawrence, Samuel J D; Wade, Alex R; Morland, Antony B

2016-05-25

Representations in early visual areas are organized on the basis of retinotopy, but this organizational principle appears to lose prominence in the extrastriate cortex. Nevertheless, an extrastriate region, such as the shape-selective lateral occipital cortex (LO), must still base its activation on the responses from earlier retinotopic visual areas, implying that a transition from retinotopic to "functional" organizations should exist. We hypothesized that such a transition may lie in LO-1 or LO-2, two visual areas lying between retinotopically defined V3d and functionally defined LO. Using a rapid event-related fMRI paradigm, we measured neural similarity in 12 human participants between pairs of stimuli differing along dimensions of shape exemplar and shape complexity within both retinotopically and functionally defined visual areas. These neural similarity measures were then compared with low-level and more abstract (curvature-based) measures of stimulus similarity. We found that low-level, but not abstract, stimulus measures predicted V1-V3 responses, whereas the converse was true for LO, a double dissociation. Critically, abstract stimulus measures were most predictive of responses within LO-2, akin to LO, whereas both low-level and abstract measures were predictive for responses within LO-1, perhaps indicating a transitional point between those two organizational principles. Similar transitions to abstract representations were not observed in the more ventral stream passing through V4 and VO-1/2. The transition we observed in LO-1 and LO-2 demonstrates that a more "abstracted" representation, typically considered the preserve of "category-selective" extrastriate cortex, can nevertheless emerge in retinotopic regions. Visual areas are typically identified either through retinotopy (e.g., V1-V3) or from functional selectivity [e.g., shape-selective lateral occipital complex (LOC)]. We combined these approaches to explore the nature of shape representations through the visual hierarchy. Two different representations emerged: the first reflected low-level shape properties (dependent on the spatial layout of the shape outline), whereas the second captured more abstract curvature-related shape features. Critically, early visual cortex represented low-level information but this diminished in the extrastriate cortex (LO-1/LO-2/LOC), in which the abstract representation emerged. Therefore, this work further elucidates the nature of shape representations in the LOC, provides insight into how those representations emerge from early retinotopic cortex, and crucially demonstrates that retinotopically tuned regions (LO-1/LO-2) are not necessarily constrained to retinotopic representations. Copyright © 2016 Vernon et al.

Co-expression of COX-2 and 5-LO in primary glioblastoma is associated with poor prognosis.

PubMed

Wang, Xingfu; Chen, Yupeng; Zhang, Sheng; Zhang, Lifeng; Liu, Xueyong; Zhang, Li; Li, Xiaoling; Chen, Dayang

2015-11-01

Cyclooxygenase-2 (COX-2) and 5-lipoxygenase (5-LO) are important factors in tumorigenesis and malignant progression; however, studies of their roles in glioblastoma have produced conflicting results. To define the frequencies of COX-2 and 5-LO expression and their correlation with clinicopathological features and prognosis, tumor tissues from 76 cases of newly diagnosed primary ordinary glioblastoma were examined for COX-2 and 5-LO expression by immunohistochemistry. The expression levels of COX-2 and 5-LO and the relationships between the co-expression of COX-2/5-LO and patient age and gender, edema index (EI), Karnofsky Performance Scale and overall survival (OS) were analyzed. COX-2 and 5-LO were expressed in 73.7 % (56/76) and 92.1 % (70/76) of the samples, respectively. Among the clinicopathological characteristics, only age (>60 years) exhibited a significant association with the high expression of COX-2. No statistically significant correlations were found in the 5-LO cohort. A significant positive correlation was revealed between the COX-2 and 5-LO scores (r = 0.374; p = 0.001). The elevated co-expression of COX-2 and 5-LO was observed primarily in the patients over the age of 60 years. Patients with a high expression of COX-2 had a significantly shorter OS (p < 0.01), whereas the immunoexpression of 5-LO was not associated with the OS of patients with glioblastoma. Survival analysis indicated that simultaneous high levels of COX-2 and 5-LO expression were significantly correlated with poor OS and, conversely, that a low/low expression pattern of these two proteins was significantly associated with better OS (p < 0.05). Moreover, the Cox multivariable proportional hazard model showed that a high expression of COX-2, high co-expression of COX-2 and 5-LO, and a high Ki-67 index were significant predictors of shorter OS in primary glioblastoma, independent of age, gender, EI, 5-LO expression and p53 status. The hazard ratios for OS were 2.347 (95 % CI 1.30-4.25, p = 0.005), 1.900 (95 % CI 1.30-2.78, p = 0.001), and 2.210 (95 % CI 1.19-4.09, p = 0.011), respectively. These results suggest that COX-2 and 5-LO play roles in tumorigenesis and the progression of primary glioblastoma and that the co-expression pattern of COX-2/5-LO may be used as an independent prognostic factor in this disease.

Multivariate Patterns in the Human Object-Processing Pathway Reveal a Shift from Retinotopic to Shape Curvature Representations in Lateral Occipital Areas, LO-1 and LO-2

PubMed Central

Vernon, Richard J. W.; Gouws, André D.; Lawrence, Samuel J. D.; Wade, Alex R.

2016-01-01

Representations in early visual areas are organized on the basis of retinotopy, but this organizational principle appears to lose prominence in the extrastriate cortex. Nevertheless, an extrastriate region, such as the shape-selective lateral occipital cortex (LO), must still base its activation on the responses from earlier retinotopic visual areas, implying that a transition from retinotopic to “functional” organizations should exist. We hypothesized that such a transition may lie in LO-1 or LO-2, two visual areas lying between retinotopically defined V3d and functionally defined LO. Using a rapid event-related fMRI paradigm, we measured neural similarity in 12 human participants between pairs of stimuli differing along dimensions of shape exemplar and shape complexity within both retinotopically and functionally defined visual areas. These neural similarity measures were then compared with low-level and more abstract (curvature-based) measures of stimulus similarity. We found that low-level, but not abstract, stimulus measures predicted V1–V3 responses, whereas the converse was true for LO, a double dissociation. Critically, abstract stimulus measures were most predictive of responses within LO-2, akin to LO, whereas both low-level and abstract measures were predictive for responses within LO-1, perhaps indicating a transitional point between those two organizational principles. Similar transitions to abstract representations were not observed in the more ventral stream passing through V4 and VO-1/2. The transition we observed in LO-1 and LO-2 demonstrates that a more “abstracted” representation, typically considered the preserve of “category-selective” extrastriate cortex, can nevertheless emerge in retinotopic regions. SIGNIFICANCE STATEMENT Visual areas are typically identified either through retinotopy (e.g., V1–V3) or from functional selectivity [e.g., shape-selective lateral occipital complex (LOC)]. We combined these approaches to explore the nature of shape representations through the visual hierarchy. Two different representations emerged: the first reflected low-level shape properties (dependent on the spatial layout of the shape outline), whereas the second captured more abstract curvature-related shape features. Critically, early visual cortex represented low-level information but this diminished in the extrastriate cortex (LO-1/LO-2/LOC), in which the abstract representation emerged. Therefore, this work further elucidates the nature of shape representations in the LOC, provides insight into how those representations emerge from early retinotopic cortex, and crucially demonstrates that retinotopically tuned regions (LO-1/LO-2) are not necessarily constrained to retinotopic representations. PMID:27225766

Ionic liquids at the surface of graphite: Wettability and structure

NASA Astrophysics Data System (ADS)

Bordes, Emilie; Douce, Laurent; Quitevis, Edward L.; Pádua, Agílio A. H.; Costa Gomes, Margarida

2018-05-01

The aim of this work is to provide a better understanding of the interface between graphite and different molecular and ionic liquids. Experimental measurements of the liquid surface tension and of the graphite-liquid contact angle for sixteen ionic liquids and three molecular liquids are reported. These experimental values allowed the calculation of the solid/liquid interfacial energy that varies, for the ionic liquids studied, between 14.5 mN m-1 for 1-ethyl-3-methylimidazolium dicyanamide and 37.8 mN m-1 for 3-dodecyl-1-(naphthalen-1-yl)-1H-imidazol-3-ium tetrafluoroborate. Imidazolium-based ionic liquids with large alkyl side-chains or functionalized with benzyl groups seem to interact more favourably with freshly peeled graphite surfaces. Even if the interfacial energy seems a good descriptor to assess the affinity of a liquid for a carbon-based solid material, we conclude that both the surface tension of the liquid and the contact angle between the liquid and the solid can be significant. Molecular dynamics simulations were used to investigate the ordering of the ions near the graphite surface. We conclude that the presence of large alkyl side-chains in the cations increases the ordering of ions at the graphite surface. Benzyl functional groups in the cations lead to a large affinity towards the graphite surface.

Navy Supplement to the DOD Dictionary of Military and Associated Terms

DTIC Science & Technology

2011-04-01

light harpoon landing restraint system LI interference level LI/ LO lock-in/lock-out LIA laser illuminator assembly LIC low-intensity conflict lidar...monitoring system LMSR large, medium-speed roll-on/roll-off (ship) LN legalman (USN rating) LND land LNO liaison officer LO locked open; low...observable; lubricating oil fill, transfer and purification LO /LI lock-out/lock-in LO / LO lift-on/lift-off LOA letter of approval; letter of authorization

Navy Supplement to the DOD Dictionary of Military and Associated Terms

DTIC Science & Technology

2012-06-01

rate LI interference level LI/ LO lock-in/lock-out LIA laser illuminator assembly LIC low-intensity conflict lidar laser identification, detection, and...liaison officer LO locked open; low observable; lubricating oil fill, transfer and purification LO /LI lock-out/lock-in LO / LO lift-on/lift-off LOA letter...aid to navigation LOS launch on search; law of the sea; line of sight; line of sound; lubricating oil service, main LOT letter of transmittal LOTS

Advanced oxygen-hydrocarbon rocket engine study

NASA Technical Reports Server (NTRS)

Obrien, C. J.; Ewen, R. L.

1981-01-01

This study identifies and evaluates promising LO2/HC rocket engine cycles, produces a consistent and reliable data base for vehicle optimization and design studies, demonstrates the significance of propulsion system improvements, and selects the critical technology areas necessary to realize an improved surface to orbit transportation system. Parametric LO2/HC engine data were generated over a range of thrust levels from 890 to 6672 kN (200K to 1.5M 1bF) and chamber pressures from 6890 to 34500 kN (1000 to 5000 psia). Engine coolants included RP-1, refined RP-1, LCH4, LC3H8, LO2, and LH2. LO2/RP-1 G.G. cycles were found to be not acceptable for advanced engines. The highest performing LO2/RP-1 staged combustion engine cycle utilizes LO2 as the coolant and incorporates an oxidizer rich preburner. The highest performing cycle for LO2/LCH4 and LO2/LC3H8 utilizes fuel cooling and incorporates both fuel and oxidizer rich preburners. LO2/HC engine cycles permitting the use of a third fluid LH2 coolant and an LH2 rich gas generator provide higher performance at significantly lower pump discharge pressures. The LO2/HC dual throat engine, because of its high altitude performance, delivers the highest payload for the vehicle configuration that was investigated.

Effects of lemongrass oil and citral on hepatic drug-metabolizing enzymes, oxidative stress, and acetaminophen toxicity in rats.

PubMed

Li, Chien-Chun; Yu, Hsiang-Fu; Chang, Chun-Hua; Liu, Yun-Ta; Yao, Hsien-Tsung

2018-01-01

The essential oil from a lemongrass variety of Cymbopogon flexuosus [lemongrass oil (LO)] is used in various food and aroma industry products and exhibits biological activities, such as anticancer and antimicrobial activities. To investigate the effects of 200 LO (200 mg/kg) and 400 LO (400 mg/kg) and its major component, citral (240 mg/kg), on drug-metabolizing enzymes, oxidative stress, and acetaminophen toxicity in the liver, male Sprague-Dawley rats were fed a pelleted diet and administered LO or citral by gavage for 2 weeks. After 2 weeks of feeding, the effects of LO and citral on the metabolism and toxicity of acetaminophen were determined. The results showed that rats treated with 400 LO or citral had significantly reduced hepatic testosterone 6β-hydroxylation and ethoxyresorufin O-deethylation activities. In addition, NAD(P)H:quinone oxidoreductase 1 activity was significantly increased by citral, and Uridine 5'-diphospho (UDP) glucurosyltransferase activity was significantly increased by 400 LO in the rat liver. Treatment with 400 LO or citral reduced lipid peroxidation and reactive oxygen species levels in the liver. After acetaminophen treatment, however, LO and citral treatment resulted in little or no change in plasma alanine aminotransferase activity and acetaminophen-protein adducts content in the liver. Our results indicate that LO and citral may change the activities of drug-metabolizing enzymes and reduce oxidative stress in the liver. However, LO and citral may not affect the detoxification of acetaminophen. Copyright © 2017. Published by Elsevier B.V.

Science Using an Electrostatic Levitation Furnace in the MUCAT Sector at the APS

NASA Technical Reports Server (NTRS)

Goldman, A.; Kelton, K. F.; Rogers, J. R.

2004-01-01

The original motivation for the construction of the BESL prototype was to obtain the first proof of a 50-year-old hypothesis regarding the solidification of liquid metals. Since the 1950s it has been known that under proper conditions liquid metals can be cooled below their melting temperature (undercooled) without crystallizing to the stable solid phase. In 1952 Frank proposed that this was because the atoms in the metallic liquid were arranged with the symmetry of an icosahedron, a Platonic solid consisting of 20 tetrahedra (4-sided pyramid-shaped polyhedra) arranged around a common center. Since this local atomic order is incompatible with the long-range translational periodicity of crystal phases, a barrier is formed to the formation of small regions of the crystal phase, the nucleation barrier. A proof of Frank's hypothesis required a direct correlation between measured icosahedral order in the undercooled liquid and the nucleation barrier. The tendency of sample containers to catalyze nucleation obscured this relation, requiring containerless techniques. Combining containerless processing techniques for electrostatically levitated droplets (ESL) with x-ray synchrotron methods, a team from Washington University, St. Louis, MO, NASA Marshall Space Flight Center, and MUCAT at the APS demonstrated an increasing icosahedral order in TiZrNi liquids with decreasing temperature below the melting temperature. The increased icosahedral order caused the transformation of the liquid to a metastable icosahedral quasicrystal phase, instead of the stable tetrahedrally-coordinated crystal intermetallic, giving the first clear demonstration of the connection between the nucleation barrier and the local structure of the liquid, verifying Frank's hypothesis for this alloy.

Interfacial ordering of thermotropic liquid crystals triggered by the secondary structures of oligopeptides.

PubMed

Wang, Xiaoguang; Yang, Pei; Mondiot, Frederic; Li, Yaoxin; Miller, Daniel S; Chen, Zhan; Abbott, Nicholas L

2015-12-07

We report that assemblies formed by eight oligopeptides at phospholipid-decorated interfaces of thermotropic liquid crystals (LCs) trigger changes in ordering of the LCs that are dependent on the secondary structures of the oligopeptides (as characterized in situ using infrared-visible sum-frequency spectroscopy).

DOE Office of Scientific and Technical Information (OSTI.GOV)

Erchinger, J. L.; Orrell, John L.; Aalseth, C. E.

The Ultra-Low Background Liquid Scintillation Counter developed by Pacific Northwest National Laboratory will expand the application of liquid scintillation counting by enabling lower detection limits and smaller sample volumes. By reducing the overall count rate of the background environment approximately 2 orders of magnitude below that of commercially available systems, backgrounds on the order of tens of counts per day over an energy range of ~3–3600 keV can be realized. Finally, initial test results of the ULB LSC show promising results for ultra-low background detection with liquid scintillation counting.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hayden, Patrick; Winter, Andreas; Department of Computer Science, University of Bristol, Merchant Venturers Building, Woodland Road, Bristol BS8 1UB

We study the amount of communication needed for two parties to transform some given joint pure state into another one, either exactly or with some fidelity. Specifically, we present a method to lower bound this communication cost even when the amount of entanglement does not increase. Moreover, the bound applies even if the initial state is supplemented with unlimited entanglement in the form of EPR (Einstein-Podolsky-Rosen) pairs and the communication is allowed to be quantum mechanical. We then apply the method to the determination of the communication cost of asymptotic entanglement concentration and dilution. While concentration is known to requiremore » no communication whatsoever, the best known protocol for dilution, discovered by H.-K. Lo and S. Popescu [Phys. Rev. Lett. 83, 1459 (1999)], requires exchange of a number of bits that is of the order of the square root of the number of EPR pairs. Here we prove a matching lower bound of the same asymptotic order, demonstrating the optimality of the Lo-Popescu protocol up to a constant factor and establishing the existence of a fundamental asymmetry between the concentration and dilution tasks. We also discuss states for which the minimal communication cost is proportional to their entanglement, such as the states recently introduced in the context of 'embezzling entanglement' (W. van Dam and P. Hayden, e-print quant-ph/0201041)« less

Static and dynamic dielectric properties of strongly polar liquids in the vicinity of first order and weakly first order phase transitions

NASA Astrophysics Data System (ADS)

Jadżyn, Jan; Czechowski, Grzegorz; Legrand, Christian; Douali, Redouane

2003-04-01

The paper presents the results of measurements of the linear dielectric properties of the compounds from the homologous series of alkylcyanobiphenyls (CnH2n+1PhPhCN, nCB) in the vicinity of the first order transition (from the isotropic liquid to the crystalline phase) of nonmesogenic nCB’s (n=2 4) and the weakly first order transition (from the isotropic liquid to the nematic phase) of 5CB. The experimental method for the separation of the critical part of the static permittivity derivative and the activation energy for rotation of the mesogenic molecules, in the vicinity of weakly first order phase transition, is proposed. It is shown that the critical temperature dependence of the permittivity and the activation energy can be described with a function of (T-T*)-α type, with the same values of the temperature of virtual transition of the second order (T*) and the critical exponent (α).

Pre-ordering of interfacial water in the pathway of heterogeneous ice nucleation does not lead to a two-step crystallization mechanism.

PubMed

Lupi, Laura; Peters, Baron; Molinero, Valeria

2016-12-07

According to Classical Nucleation Theory (CNT), the transition from liquid to crystal occurs in a single activated step with a transition state controlled by the size of the crystal embryo. This picture has been challenged in the last two decades by several reports of two-step crystallization processes in which the liquid first produces pre-ordered or dense domains, within which the crystal nucleates in a second step. Pre-ordering preceding crystal nucleation has been recently reported in simulations of ice crystallization, raising the question of whether the mechanism of ice nucleation involves two steps. In this paper, we investigate the heterogeneous nucleation of ice on carbon surfaces. We use molecular simulations with efficient coarse-grained models combined with rare event sampling methods and free energy calculations to elucidate the role of pre-ordering of liquid water at the carbon surface in the reaction coordinate for heterogeneous nucleation. We find that ice nucleation proceeds through a classical mechanism, with a single barrier between liquid and crystal. The reaction coordinate that determines the crossing of the nucleation barrier is the size of the crystal nucleus, as predicted by CNT. Wetting of the critical ice nuclei within pre-ordered domains decreases the nucleation barrier, increasing the nucleation rates. The preferential pathway for crystallization involves the early creation of pre-ordered domains that are the birthplace of the ice crystallites but do not represent a minimum in the free energy pathway from liquid to ice. We conclude that a preferential pathway through an intermediate-order precursor does not necessarily result in a two-step mechanism.

A stable 1D multigroup high-order low-order method

DOE PAGES

Yee, Ben Chung; Wollaber, Allan Benton; Haut, Terry Scot; ...

2016-07-13

The high-order low-order (HOLO) method is a recently developed moment-based acceleration scheme for solving time-dependent thermal radiative transfer problems, and has been shown to exhibit orders of magnitude speedups over traditional time-stepping schemes. However, a linear stability analysis by Haut et al. (2015 Haut, T. S., Lowrie, R. B., Park, H., Rauenzahn, R. M., Wollaber, A. B. (2015). A linear stability analysis of the multigroup High-Order Low-Order (HOLO) method. In Proceedings of the Joint International Conference on Mathematics and Computation (M&C), Supercomputing in Nuclear Applications (SNA) and the Monte Carlo (MC) Method; Nashville, TN, April 19–23, 2015. American Nuclear Society.)more » revealed that the current formulation of the multigroup HOLO method was unstable in certain parameter regions. Since then, we have replaced the intensity-weighted opacity in the first angular moment equation of the low-order (LO) system with the Rosseland opacity. Furthermore, this results in a modified HOLO method (HOLO-R) that is significantly more stable.« less

Solution processed nanogap organic diodes based on liquid crystalline materials

NASA Astrophysics Data System (ADS)

Wang, Yi-Fei; Iino, Hiroaki; Hanna, Jun-ichi

2017-09-01

Co-planar nanogap organic diodes were fabricated with smectic liquid crystalline materials of the benzothienobenzothiophene (BTBT) derivative by a spin-coating technique. A high rectification ratio of the order of 106 at ±3 V was achieved when a liquid crystalline material of 2,7-didecyl benzothieno[3,2-b][1]benzothiophene (10-BTBT-10) was used in a device configuration of Al/10-BTBT-10/pentafluorobenzenethiol-treated Au on a glass substrate, which was 4 orders higher than that of the device based on non-liquid crystalline materials of 2,7-dibutyl benzothieno[3,2-b][1]benzothiophene (4-BTBT-4) and BTBT. Similar results were also observed when another liquid crystalline material of ω, ω'-dioctylterthiophene (8-TTP-8) and a non-liquid crystalline material of terthiophene (TTP) were used. These improved rectifications can be ascribed to the self-assembly properties and controllable molecular orientation of liquid crystalline materials, which made uniform perpendicular oriented polycrystalline films favorable for superior charge transport in nano-channels.

Integrated liquid-core optical fibers for ultra-efficient nonlinear liquid photonics.

PubMed

Kieu, K; Schneebeli, L; Norwood, R A; Peyghambarian, N

2012-03-26

We have developed a novel integrated platform for liquid photonics based on liquid core optical fiber (LCOF). The platform is created by fusion splicing liquid core optical fiber to standard single-mode optical fiber making it fully integrated and practical - a major challenge that has greatly hindered progress in liquid-photonic applications. As an example, we report here the realization of ultralow threshold Raman generation using an integrated CS₂ filled LCOF pumped with sub-nanosecond pulses at 532 nm and 1064 nm. The measured energy threshold for the Stokes generation is 1nJ, about three orders of magnitude lower than previously reported values in the literature for hydrogen gas, a popular Raman medium. The integrated LCOF platform opens up new possibilities for ultralow power nonlinear optics such as efficient white light generation for displays, mid-IR generation, slow light generation, parametric amplification, all-optical switching and wavelength conversion using liquids that have orders of magnitude larger optical nonlinearities compared with silica glass.

Anatomy of Bs → PV decays and effects of next-to-leading order contributions in the perturbative QCD factorization approach

NASA Astrophysics Data System (ADS)

Yan, Da-Cheng; Yang, Ping; Liu, Xin; Xiao, Zhen-Jun

2018-06-01

In this paper, we will make systematic calculations for the branching ratios and the CP-violating asymmetries of the twenty one Bbars0 → PV decays by employing the perturbative QCD (PQCD) factorization approach. Besides the full leading-order (LO) contributions, all currently known next-to-leading order (NLO) contributions are taken into account. We found numerically that: (a) the NLO contributions can provide ∼ 40% enhancement to the LO PQCD predictions for B (Bbars0 →K0K bar * 0) and B (Bbars0 →K±K*∓), or a ∼ 37% reduction to B (Bbars0 →π-K*+); and we confirmed that the inclusion of the known NLO contributions can improve significantly the agreement between the theory and those currently available experimental measurements; (b) the total effects on the PQCD predictions for the relevant Bs0 → P transition form factors after the inclusion of the NLO twist-2 and twist-3 contributions is generally small in magnitude: less than 10% enhancement respect to the leading order result; (c) for the "tree" dominated decay Bbars0 →K+ρ- and the "color-suppressed-tree" decay Bbars0 →π0K*0, the big difference between the PQCD predictions for their branching ratios are induced by different topological structure and by interference effects among the decay amplitude AT,C and AP: constructive for the first decay but destructive for the second one; and (d) for Bbars0 → V (η ,η‧) decays, the complex pattern of the PQCD predictions for their branching ratios can be understood by rather different topological structures and the interference effects between the decay amplitude A (Vηq) and A (Vηs) due to the η-η‧ mixing.

First-order wetting transition at a liquid-vapor interface

NASA Technical Reports Server (NTRS)

Schmidt, J. W.; Moldover, M. R.

1983-01-01

Evidence from reflectance and contact angle measurements is presented that three-phase mixtures of i-C3H7OH-C7F14 exhibit a first-order wetting phase transition at the liquid-vapor interface at 38 C. Equilibration phenomena support this interpretation. Ellipsometry was used to measure the apparent thickness of the intruding layer in the three-phase mixture. At temperatures slightly above the wetting temperature T(w), the intruding layer's thickness is several hundred angstroms and its variation with temperature is extremely weak. Below T(w), three-phase contact can occur between the vapor and both the upper and lower liquid phases; one of the angles which characterizes this contact has a very simple temperature dependence. The thickness of the intruding layer, monitored as the solutions approached equilibrium, is found to depend quite weakly on the height spanned by the upper liquid phase in the vicinity of a first-order wetting transition.

Liquidity crisis, granularity of the order book and price fluctuations

NASA Astrophysics Data System (ADS)

Cristelli, M.; Alfi, V.; Pietronero, L.; Zaccaria, A.

2010-01-01

We introduce a microscopic model for the dynamics of the order book to study how the lack of liquidity influences price fluctuations. We use the average density of the stored orders (granularity g) as a proxy for liquidity. This leads to a Price Impact Surface which depends on both volume ω and g. The dependence on the volume (averaged over the granularity) of the Price Impact Surface is found to be a concave power law function <φ(ω,g)>g ˜ ωδ with δ ≈ 0.59. Instead the dependence on the granularity is φ(ω,g|ω) ˜ gα with α ≈ -1, showing a divergence of price fluctuations in the limit g → 0. Moreover, even in intermediate situations of finite liquidity, this effect can be very large and it is a natural candidate for understanding the origin of large price fluctuations.

A structural model for surface-enhanced stabilization in some metallic glass formers

NASA Astrophysics Data System (ADS)

Levchenko, Elena V.; Evteev, Alexander V.; Yavari, Alain R.; Louzguine-Luzgin, Dmitri V.; Belova, Irina V.; Murch, Graeme E.

2013-01-01

A structural model for surface-enhanced stabilization in some metallic glass formers is proposed. In this model, the alloy surface structure is represented by five-layer Kagomé-net-based lateral ordering. Such surface structure has intrinsic abilities to stabilize icosahedral-like short-range order in the bulk, acting as 'a cloak of liquidity'. In particular, recent experimental observations of surface-induced lateral ordering and a very high glass forming ability of the liquid alloy Au49Ag5.5Pd2.3Cu26.9Si16.3 can be united using this structural model. This model may be useful for the interpretation of surface structure of other liquid alloys with a high glass forming ability. In addition, it suggests the possibility of guiding the design of the surface coating of solid containers for the stabilization of undercooled liquids.

77 FR 2715 - D'Lo Gas Storage, LLC; Notice of Application

Federal Register 2010, 2011, 2012, 2013, 2014

2012-01-19

... Storage, LLC; Notice of Application Take notice that on December 29, 2011, D'Lo Gas Storage, LLC (D'Lo... natural gas storage project to be located in Simpson County, Mississippi. Additionally, D'Lo requests a...- discriminatory firm interruptible natural gas storage services and hub services, and a blanket certificate...

Contrast Invariant Interest Point Detection by Zero-Norm LoG Filter.

PubMed

Zhenwei Miao; Xudong Jiang; Kim-Hui Yap

2016-01-01

The Laplacian of Gaussian (LoG) filter is widely used in interest point detection. However, low-contrast image structures, though stable and significant, are often submerged by the high-contrast ones in the response image of the LoG filter, and hence are difficult to be detected. To solve this problem, we derive a generalized LoG filter, and propose a zero-norm LoG filter. The response of the zero-norm LoG filter is proportional to the weighted number of bright/dark pixels in a local region, which makes this filter be invariant to the image contrast. Based on the zero-norm LoG filter, we develop an interest point detector to extract local structures from images. Compared with the contrast dependent detectors, such as the popular scale invariant feature transform detector, the proposed detector is robust to illumination changes and abrupt variations of images. Experiments on benchmark databases demonstrate the superior performance of the proposed zero-norm LoG detector in terms of the repeatability and matching score of the detected points as well as the image recognition rate under different conditions.

LPS Increases 5-LO Expression on Monocytes via an Activation of Akt-Sp1/NF-κB Pathways.

PubMed

Lee, Seung Jin; Seo, Kyo Won; Kim, Chi Dae

2015-05-01

5-Lipoxygenase (5-LO) plays a pivotal role in the progression of atherosclerosis. Therefore, this study investigated the molecular mechanisms involved in 5-LO expression on monocytes induced by LPS. Stimulation of THP-1 monocytes with LPS (0~3 µg/ml) increased 5-LO promoter activity and 5-LO protein expression in a concentration-dependent manner. LPS-induced 5-LO expression was blocked by pharmacological inhibition of the Akt pathway, but not by inhibitors of MAPK pathways including the ERK, JNK, and p38 MAPK pathways. In line with these results, LPS increased the phosphorylation of Akt, suggesting a role for the Akt pathway in LPS-induced 5-LO expression. In a promoter activity assay conducted to identify transcription factors, both Sp1 and NF-κB were found to play central roles in 5-LO expression in LPS-treated monocytes. The LPS-enhanced activities of Sp1 and NF-κB were attenuated by an Akt inhibitor. Moreover, the LPS-enhanced phosphorylation of Akt was significantly attenuated in cells pretreated with an anti-TLR4 antibody. Taken together, 5-LO expression in LPS-stimulated monocytes is regulated at the transcriptional level via TLR4/Akt-mediated activations of Sp1 and NF-κB pathways in monocytes.

Hypoxia-Response Element (HRE)–Directed Transcriptional Regulation of the Rat Lysyl Oxidase Gene in Response to Cobalt and Cadmium

PubMed Central

Li, Wande

2013-01-01

Lysyl oxidase (LO) catalyzes crosslink of collagen, elastin, and histone H1, stabilizing the extracellular matrix and cell nucleus. This enzyme displays dual functions for tumorigenesis, i.e., as a tumor suppressor inactivating the ras oncogene and as a tumor promoter enhancing malignant cell metastasis. To elucidate LO transcriptional regulation, we have cloned the 804 base pair region upstream of the translation start site (ATG) of the rat LO gene with the maximal promoter activity. Computer analysis indicated that at least four hypoxia-response element (HRE) consensuses (5′-ACGTG-3′) exist in the cloned LO promoter. Treatment of rat lung fibroblasts (RFL6) with CoCl2 (Co, 10–100 μM), a chemical hypoxia reagent, enhanced LO mRNA expression and promoter activities. Overexpression of LO was associated with upregulation of hypoxia-inducible factor (HIF)-1α at mRNA levels in cobalt (Co)–treated cells. Thus, LO is a hypoxia-responsive gene. Dominant negative-HIF-1α inhibited LO promoter activities stimulated by Co. Electrophoretic mobility shift, oligonucleotide competition, and in vitro translated HIF-1α binding assays indicated that only one HRE mapped at −387/−383 relative to ATG was functionally active among four consensuses. Site-directed mutation of this HRE significantly diminished the Co-induced and LO promoter-directed expression of the reporter gene. Cadmium (Cd), an inducer of reactive oxygen species, inhibited HIF-1α mRNA expression and HIF-1α binding to the LO gene in Co-treated cells as revealed by RT-PCR and ChIP assays, respectively. Thus, modulation of the HRE activity by Co and Cd plays a critical role in LO gene transactivation. PMID:23161664

Hypoxia-response element (HRE)-directed transcriptional regulation of the rat lysyl oxidase gene in response to cobalt and cadmium.

PubMed

Gao, Song; Zhou, Jing; Zhao, Yinzhi; Toselli, Paul; Li, Wande

2013-04-01

Lysyl oxidase (LO) catalyzes crosslink of collagen, elastin, and histone H1, stabilizing the extracellular matrix and cell nucleus. This enzyme displays dual functions for tumorigenesis, i.e., as a tumor suppressor inactivating the ras oncogene and as a tumor promoter enhancing malignant cell metastasis. To elucidate LO transcriptional regulation, we have cloned the 804 base pair region upstream of the translation start site (ATG) of the rat LO gene with the maximal promoter activity. Computer analysis indicated that at least four hypoxia-response element (HRE) consensuses (5'-ACGTG-3') exist in the cloned LO promoter. Treatment of rat lung fibroblasts (RFL6) with CoCl2 (Co, 10-100 μM), a chemical hypoxia reagent, enhanced LO mRNA expression and promoter activities. Overexpression of LO was associated with upregulation of hypoxia-inducible factor (HIF)-1α at mRNA levels in cobalt (Co)-treated cells. Thus, LO is a hypoxia-responsive gene. Dominant negative-HIF-1α inhibited LO promoter activities stimulated by Co. Electrophoretic mobility shift, oligonucleotide competition, and in vitro translated HIF-1α binding assays indicated that only one HRE mapped at -387/-383 relative to ATG was functionally active among four consensuses. Site-directed mutation of this HRE significantly diminished the Co-induced and LO promoter-directed expression of the reporter gene. Cadmium (Cd), an inducer of reactive oxygen species, inhibited HIF-1α mRNA expression and HIF-1α binding to the LO gene in Co-treated cells as revealed by RT-PCR and ChIP assays, respectively. Thus, modulation of the HRE activity by Co and Cd plays a critical role in LO gene transactivation.

Oxidative stress in elite athletes training at moderate altitude and at sea level.

PubMed

León-López, Josefa; Calderón-Soto, Carmen; Pérez-Sánchez, Matías; Feriche, Belén; Iglesias, Xavier; Chaverri, Diego; Rodréguez, Ferran A

2018-03-24

Using a controlled parallel group longitudinal trial design, we investigated the effects of different training interventions on the prooxidant/antioxidant status of elite athletes: living and training at moderate altitude for 3 (Hi-Hi3) and 4 weeks (Hi-Hi), and for 4 weeks too, living high and training high and low (Hi-HiLo) and living and training at sea level (Lo-Lo). From 61 swimmers, 54 completed the study. Nitrites, carbonyls, and lipid peroxidation (LPO) levels were assessed in plasma. Enzymatic antioxidants glutathione peroxidase (GPx) and glutathione reductase (GRd), and non-enzymatic antioxidants total glutathione (GST), reduced glutathione (GSH) and oxidized glutathione (GSSG) were analysed in the erythrocyte fraction. At the end of the intervention, nitrites levels were similar in all altitude groups but higher than in the Lo-Lo controls (P = .02). Hi-HiLo had greater GPx activity than Hi-Hi and Hi-Hi3 during most of the intervention (P ≤ .001). GRd activity was higher in Lo-Lo than in Hi-Hi at the end of the training camp (P ≤ .001). All groups showed increased levels of LPO, except Lo-Lo, and carbonyls at the end of the study (P ≤ .001). Training at altitude for 3 or 4 weeks drives oxidative stress leading to cellular damage mainly by worsening the antioxidant capacities. The GSSG/GSH ratio appears to be related to perceived exertion and fatigue. The stronger antioxidant defence showed by the Hi-HiLo group suggests an inverse relationship between redox alterations and performance. Further studies are required to investigate the role of oxidative stress in acclimatization, performance, and health.

Lo/Ld phase coexistence modulation induced by GM1.

PubMed

Puff, Nicolas; Watanabe, Chiho; Seigneuret, Michel; Angelova, Miglena I; Staneva, Galya

2014-08-01

Lipid rafts are assumed to undergo biologically important size-modulations from nanorafts to microrafts. Due to the complexity of cellular membranes, model systems become important tools, especially for the investigation of the factors affecting "raft-like" Lo domain size and the search for Lo nanodomains as precursors in Lo microdomain formation. Because lipid compositional change is the primary mechanism by which a cell can alter membrane phase behavior, we studied the effect of the ganglioside GM1 concentration on the Lo/Ld lateral phase separation in PC/SM/Chol/GM1 bilayers. GM1 above 1mol % abolishes the formation of the micrometer-scale Lo domains observed in GUVs. However, the apparently homogeneous phase observed in optical microscopy corresponds in fact, within a certain temperature range, to a Lo/Ld lateral phase separation taking place below the optical resolution. This nanoscale phase separation is revealed by fluorescence spectroscopy, including C12NBD-PC self-quenching and Laurdan GP measurements, and is supported by Gaussian spectral decomposition analysis. The temperature of formation of nanoscale Lo phase domains over an Ld phase is determined, and is shifted to higher values when the GM1 content increases. A "morphological" phase diagram could be made, and it displays three regions corresponding respectively to Lo/Ld micrometric phase separation, Lo/Ld nanometric phase separation, and a homogeneous Ld phase. We therefore show that a lipid only-based mechanism is able to control the existence and the sizes of phase-separated membrane domains. GM1 could act on the line tension, "arresting" domain growth and thereby stabilizing Lo nanodomains. Copyright © 2014 Elsevier B.V. All rights reserved.

A double blind randomized clinical trial comparing lingualized and fully bilateral balanced posterior occlusion for conventional complete dentures.

PubMed

Kawai, Yasuhiko; Ikeguchi, Nobuyuki; Suzuki, Asako; Kuwashima, Azusa; Sakamoto, Ryuji; Matsumaru, Yuichi; Kimoto, Suguru; Iijima, Morio; Feine, Jocelyne Sylvia

2017-04-01

A lingualized occlusion (LO) for complete dentures reduces lateral inferences and occlusal force contacts and direction; thus, LO is theorized to be more suitable for patients with compromised ridges than fully bilateral balanced articulation (FBBA). However, no studies have yet provided evidence to support LO in edentate patients with compromised alveolar ridges. The purpose of this study was to compare LO and FBBA in edentulous individuals with compromised ridges. Sixty edentulous individuals were randomly allocated into groups and received dentures with either LO or FBBA. Following delivery, several denture-related satisfaction variables were measured using 100mm visual analogue scales; oral health-related quality of life (OHRQoL) was also assessed using the Oral Health Impact Profile (OHIP). Sub-group analyses of the effect of moderate and severe mandibular bone loss were also carried out. No significant differences were detected between LO and FBBA with the primary outcome. At 6 months, participants with severely atrophied mandibles and FBBA rated their satisfaction with retention of mandibular dentures significantly lower than those with LO (median LO: 86, FBBA: 58.5, p=0.03). They also had significantly lower OHRQoL for the domain of Pain (median LO: 4, FBBA: 5, p=0.02). General satisfaction and total OHIP scores significantly improved between baseline and 6 months only for the LO subjects with severely atrophied mandibles (satisfaction: p=0.003, OHIP total score: p=0.0007). The results indicate that the LO occlusal scheme with hard resin artificial teeth is more efficient for patients with severely resorbed mandibular ridges. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

Space propulsion

NASA Astrophysics Data System (ADS)

Kazaroff, John M.

1993-02-01

Lewis Research Center is developing broad-based new technologies for space chemical engines to satisfy long-term needs of ETO launch vehicles and other vehicles operating in and beyond Earth orbit. Specific objectives are focused on high performance LO2/LH2 engines providing moderate thrusts of 7,5-200 klb. This effort encompasses research related to design analysis and manufacturing processes needed to apply advanced materials to subcomponents, components, and subsystems of space-based systems and related ground-support equipment. High-performance space-based chemical engines face a number of technical challenges. Liquid hydrogen turbopump impellers are often so large that they cannot be machined from a single piece, yet high stress at the vane/shroud interface makes bonding extremely difficult. Tolerances on fillets are critical on large impellers. Advanced materials and fabricating techniques are needed to address these and other issues of interest. Turbopump bearings are needed which can provide reliable, long life operation at high speed and high load with low friction losses. Hydrostatic bearings provide good performance, but transients during pump starts and stops may be an issue because no pressurized fluid is available unless a separate bearing pressurization system is included. Durable materials and/or coatings are needed that can demonstrate low wear in the harsh LO2/LH2 environment. Advanced materials are also needed to improve the lifetime, reliability and performance of other propulsion system elements such as seals and chambers.

Evaluating the Liquid Liquid Phase Transition Hypothesis of Supercoooled Water

NASA Astrophysics Data System (ADS)

Limmer, David; Chandler, David

2011-03-01

To explain the anomalous behavior of supercooled water it has been conjectured that buried within an experimentally inaccessible region of liquid water's phase diagram there exists a second critical point, which is the terminus of a first order transition line between two distinct liquid phases. The so-called liquid-liquid phase transition (LLPT) has since generated much study, though to date there is no consensus on its existence. In this talk, we will discuss our efforts to systematically study the metastable phase diagram of supercooled water through computer simulation. By employing importance-sampling techniques, we have calculated free energies as a function of the density and long-range order to determine unambiguously if two distinct liquid phases exist. We will argue that, contrary to the LLPT hypothesis, the observed phenomenology can be understood as a consequence of the limit of stability of the liquid far away from coexistence. Our results suggest that homogeneous nucleation is the cause of the increased fluctuations present upon supercooling. Further we will show how this understanding can be extended to explain experimental observations of hysteresis in confined supercooled water systems.

Individual behavior and pairwise interactions between microswimmers in anisotropic liquid

NASA Astrophysics Data System (ADS)

Sokolov, Andrey; Zhou, Shuang; Lavrentovich, Oleg D.; Aranson, Igor S.

2015-01-01

A motile bacterium swims by generating flow in its surrounding liquid. Anisotropy of the suspending liquid significantly modifies the swimming dynamics and corresponding flow signatures of an individual bacterium and impacts collective behavior. We study the interactions between swimming bacteria in an anisotropic environment exemplified by lyotropic chromonic liquid crystal. Our analysis reveals a significant localization of the bacteria-induced flow along a line coaxial with the bacterial body, which is due to strong viscosity anisotropy of the liquid crystal. Despite the fact that the average viscosity of the liquid crystal is two to three orders of magnitude higher than the viscosity of pure water, the speed of bacteria in the liquid crystal is of the same order of magnitude as in water. We show that bacteria can transport a cargo (a fluorescent particle) along a predetermined trajectory defined by the direction of molecular orientation of the liquid crystal. We demonstrate that while the hydrodynamic interaction between flagella of two close-by bacteria is negligible, the observed convergence of the swimming speeds as well as flagella waves' phase velocities may occur due to viscoelastic interaction between the bacterial bodies.

Systematic review and practice policy statements on urinary tract infection prevention in adults with spina bifida

PubMed Central

Tradewell, Michael; Pariser, Joseph J.; Nimeh, Tony

2018-01-01

Urinary tract infection (UTI) is a source of morbidity and healthcare costs in adults with spina bifida (ASB). UTI prevention strategies are often recommended, but the evidence of various approaches remains unclear. We performed a systematic review to inform a best practice policy statement for UTI prevention in ASB. On behalf of the Neurogenic Bladder Research Group (NBRG.org), we developed an a priori protocol and searched the published English literature for 30 outcomes questions addressing UTI prevention in ASB. The questions spanned the categories of antibiotics, oral supplements, bladder management factors and social support. Where there was little literature in ASB, we included literature from similar populations with neurogenic bladder (NB). Data was abstracted and then reviewed with recommendations made by consensus of all authors. Level of Evidence (LoE) and Grade of Recommendation (GoR) were according to the Oxford grading system. Of 6,433 articles identified by our search, we included 99 publications. There was sufficient evidence to support use of the following: saline bladder irrigation (LoE 1, GoR B), gentamicin bladder instillation (LoE 3, GoR C), single-use intermittent catheterization (IC) (LoE 2, GoR B), hydrophilic catheters for IC (LoE 2, GoR C), intradetrusor onabotulinumtoxinA injection (LoE 3, GoR C), hyaluronic acid (HA) instillation (LoE 1, GoR B), and care coordination (LoE 3, GoR C). There was sufficient evidence to recommend against use of the following: sterile IC (LoE 1, GoR B), oral antibiotic prophylaxis (LoE 2, GoR B), treatment of asymptomatic bacteriuria (LoE 2, GoR B), cranberry (LoE 2, GoR B), methenamine salts (LoE 1, GoR B), and ascorbic acid (LoE1, GoR B). There was insufficient evidence to make a recommendation for other outcomes. Overall, there are few studies in UTI prevention in the specific population of ASB. Research in populations similar to ASB helps to guide recommendations for UTI prevention in the challenging patient group of ASB. Future studies in UTI prevention specific to ASB are needed and should focus on areas shown to be of benefit in similar populations. PMID:29928619

Estimation of electron–phonon coupling and Urbach energy in group-I elements doped ZnO nanoparticles and thin films by sol–gel method

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vettumperumal, R.; Kalyanaraman, S., E-mail: mayura_priya2003@yahoo.co.in; Santoshkumar, B.

Highlights: • Comparison of group-I elements doped ZnO nanoparticles and thin films. • Calculation of electron–phonon coupling and phonon lifetime from Raman spectroscopy. • Estimation of interband states from Urbach energy. - Abstract: Group-I (Li, Na, K & Cs) elements doped ZnO nanoparticles (NPs) and thin films were prepared using sol–gel method. XRD data and TEM images confirm the absence of any other secondary phase different from wurtzite type ZnO. Spherical shapes of grains are observed from the surfaces of doped ZnO films by atomic force microscope images (AFM) and presences of dopants are confirmed from energy dispersive X-ray spectra.more » The Raman active E{sub 2} (high), E{sub 2} (low), E{sub 1} and A{sub 1} (LO) modes are observed from both ZnO NPs and thin films. First-order longitudinal optical (LO) phonon is found to have contributions from direct band transition and localized excitons. Electron–phonon coupling, phonon lifetime and deformation energy of ZnO are calculated based on the effect of dopants with respect to the multiple Raman LO phonon scattering. Presence of localized interbands states in doped ZnO NPs and thin films are found from the Urbach energy calculations.« less

Imaging X-Ray Polarimetry Explorer Mission Attitude Determination and Control Concept

NASA Technical Reports Server (NTRS)

Bladt, Jeff; Deininger, William D.; Kalinowski, William C.; Boysen, Mary; Bygott, Kyle; Guy, Larry; Pentz, Christina; Seckar, Chris; Valdez, John; Wedmore, Jeffrey;

High key rate continuous-variable quantum key distribution with a real local oscillator.

PubMed

Wang, Tao; Huang, Peng; Zhou, Yingming; Liu, Weiqi; Ma, Hongxin; Wang, Shiyu; Zeng, Guihua

2018-02-05

Continuous-variable quantum key distribution (CVQKD) with a real local oscillator (LO) has been extensively studied recently due to its security and simplicity. In this paper, we propose a novel implementation of a high-key-rate CVQKD with a real LO. Particularly, with the help of the simultaneously generated reference pulse, the phase drift of the signal is tracked in real time and then compensated. By utilizing the time and polarization multiplexing techniques to isolate the reference pulse and controlling the intensity of it, not only the contamination from it is suppressed, but also a high accuracy of the phase compensation can be guaranteed. Besides, we employ homodyne detection on the signal to ensure the high quantum efficiency and heterodyne detection on the reference pulse to acquire the complete phase information of it. In order to suppress the excess noise, a theoretical noise model for our scheme is established. According to this model, the impact of the modulation variance and the intensity of the reference pulse are both analysed theoretically and then optimized according to the experimental data. By measuring the excess noise in the 25km optical fiber transmission system, a 3.14Mbps key rate in the asymptotic regime proves to be achievable. This work verifies the feasibility of the high-key-rate CVQKD with a real LO within the metropolitan area.

Liquid crystal templating as an approach to spatially and temporally organise soft matter.

PubMed

van der Asdonk, Pim; Kouwer, Paul H J

2017-10-02

Chemistry quickly moves from a molecular science to a systems science. This requires spatial and temporal control over the organisation of molecules and molecular assemblies. Whilst Nature almost by default (transiently) organises her components at multiple different length scales, scientists struggle to realise even relatively straightforward patterns. In the past decades, supramolecular chemistry has taught us the rules to precisely engineer molecular assembly at the nanometre scale. At higher length scales, however, we are bound to top-down nanotechnology techniques to realise order. For soft, biological matter, many of these top-down techniques come with serious limitations since the molecules generally show low susceptibilities to the applied stimuli. A new method is based on liquid crystal templating. In this hierarchical approach, a liquid crystalline host serves as the scaffold to order polymers or assemblies. Being a liquid crystal, the host material can be ordered at many different length scales and on top of that, is highly susceptible to many external stimuli, which can even be used to manipulate the liquid crystal organisation in time. As a result, we anticipate large control over the organisation of the materials inside the liquid crystalline host. Recently, liquid crystal templating was also realised in water. This suddenly makes this tool highly applicable to start organising more delicate biological materials or even small organisms. We review the scope and limitations of liquid crystal templating and look out to where the technique may lead us.

Solid-liquid critical behavior of water in nanopores.

PubMed

Mochizuki, Kenji; Koga, Kenichiro

2015-07-07

Nanoconfined liquid water can transform into low-dimensional ices whose crystalline structures are dissimilar to any bulk ices and whose melting point may significantly rise with reducing the pore size, as revealed by computer simulation and confirmed by experiment. One of the intriguing, and as yet unresolved, questions concerns the observation that the liquid water may transform into a low-dimensional ice either via a first-order phase change or without any discontinuity in thermodynamic and dynamic properties, which suggests the existence of solid-liquid critical points in this class of nanoconfined systems. Here we explore the phase behavior of a model of water in carbon nanotubes in the temperature-pressure-diameter space by molecular dynamics simulation and provide unambiguous evidence to support solid-liquid critical phenomena of nanoconfined water. Solid-liquid first-order phase boundaries are determined by tracing spontaneous phase separation at various temperatures. All of the boundaries eventually cease to exist at the critical points and there appear loci of response function maxima, or the Widom lines, extending to the supercritical region. The finite-size scaling analysis of the density distribution supports the presence of both first-order and continuous phase changes between solid and liquid. At around the Widom line, there are microscopic domains of two phases, and continuous solid-liquid phase changes occur in such a way that the domains of one phase grow and those of the other evanesce as the thermodynamic state departs from the Widom line.

Supplementation of increasing amounts of linseed oil to dairy cows fed total mixed rations: effects on digestion, ruminal fermentation characteristics, protozoal populations, and milk fatty acid composition.

PubMed

Benchaar, C; Romero-Pérez, G A; Chouinard, P Y; Hassanat, F; Eugene, M; Petit, H V; Côrtes, C

2012-08-01

The effect of linseed oil (LO) supplementation on nutrient digestibility, forage (i.e., timothy hay) in sacco ruminal degradation, ruminal fermentation characteristics, protozoal populations, milk production, and milk fatty acid (FA) profile in dairy cows was investigated. Four ruminally cannulated, primiparous lactating cows were used in a 4 × 4 Latin square design (28-d periods). They were fed a total mixed ration (50:50 forage:concentrate (F:C) ratio [dry matter (DM) basis] without supplementation (control, CTL), or supplemented (wt/wt; DM basis) with LO at 2, 3, or 4%. Supplementation with LO had no effect on DM intake (19 kg/d) and apparent total-tract digestibility of nutrients (organic matter, neutral detergent fiber, acid detergent fiber, starch, and gross energy). Ruminal pH, ammonia, and total volatile FA concentrations were not changed by LO supplementation to diets. Extent of changes in volatile FA pattern and effective ruminal degradability of DM of timothy hay were minor. Neither the total numbers nor the genera distribution of protozoa was changed by the addition of increasing amounts of LO to the diet. Milk yield increased linearly (26.1, 27.3, 27.4, and 28.4 kg/d for CTL to LO4, respectively) as the amount of LO added to the diet increased. Milk fat content was not affected by LO supplementation, whereas milk protein content decreased linearly with increasing amounts of LO in the diet. Milk fat proportions of several intermediates of ruminal biohydrogenation of polyunsaturated FA (i.e., trans-10 18:1, trans-11 18:1, cis-9,trans-11 18:2, trans-11,cis-15 18:2, and cis-9,trans-11,cis-15 18:3) increased linearly with LO addition to the diet. The proportion of cis-9,cis-12 18:2 decreased linearly (2.06, 1.99, 1.91, and 1.83% for CTL to LO4, respectively) as the amount of LO in the diet increased. Milk fat content of cis-9,cis-12,cis-15 18:3 increased as the level of LO in the diet increased up to 3% but no further increase was observed when 4% of LO was fed (0.33, 0.79, 0.86, and 0.86% for CTL to LO4, respectively). A similar quadratic response to LO supplementation was also observed for cis-5,cis-8,cis-11,cis-14,cis-17 20:5 and cis-5,cis-7,cis-10,cis-13,cis-16 22:5. The results of the present study show that LO can be safely supplemented up to 4% in forage-based diets of dairy cows to enrich milk with potential health beneficial FA (i.e., n-3 FA) without causing any detrimental effects on rumen function, digestion, and milk production. Copyright © 2012 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Nematic order on the surface of a three-dimensional topological insulator

NASA Astrophysics Data System (ADS)

Lundgren, Rex; Yerzhakov, Hennadii; Maciejko, Joseph

2017-12-01

We study the spontaneous breaking of rotational symmetry in the helical surface state of three-dimensional topological insulators due to strong electron-electron interactions, focusing on time-reversal invariant nematic order. Owing to the strongly spin-orbit coupled nature of the surface state, the nematic order parameter is linear in the electron momentum and necessarily involves the electron spin, in contrast with spin-degenerate nematic Fermi liquids. For a chemical potential at the Dirac point (zero doping), we find a first-order phase transition at zero temperature between isotropic and nematic Dirac semimetals. This extends to a thermal phase transition that changes from first to second order at a finite-temperature tricritical point. At finite doping, we find a transition between isotropic and nematic helical Fermi liquids that is second order even at zero temperature. Focusing on finite doping, we discuss various observable consequences of nematic order, such as anisotropies in transport and the spin susceptibility, the partial breakdown of spin-momentum locking, collective modes and induced spin fluctuations, and non-Fermi-liquid behavior at the quantum critical point and in the nematic phase.

Structure and property of metal melt I: The number of residual bonds after solid-liquid phase changes

NASA Astrophysics Data System (ADS)

Mi, Guangbao; Li, Peijie; He, Liangju

2010-09-01

Based on the mechanism of metal solid-liquid phase change and the theory of liquid metal’s micro-inhomogeneity, a physical model is established between latent heats of fusion and vaporization and the numbers of residual bonds and short-range ordered atoms at the melting point inside a metal melt. Meanwhile, the mathematical derivation and proof are also offered. This model produces the numbers of residual bonds and short-range ordered atoms after the solid-liquid phase change only by using basic parameters and thermophysical properties of the crystal structure. Therefore, it presents a more effective way to analyze the melt’s structural information. By using this model, this study calculates the numbers of residual bonds and short-range ordered atoms in Al and Ni melts. The calculated results are consistent with the experimental results. Simultaneously, this study discusses the atomic number’s influence on the numbers of residual bonds and short-range ordered atoms in the melts within the first (IA) and second main group (IIA) elements.

9 CFR 113.108 - Clostridium Novyi Bacterin-Toxoid.

Code of Federal Regulations, 2014 CFR

2014-01-01

... which reacts with Lo and L+ doses of Standard Toxin according to their definitions. (ii) Lo dose. The... 0.1 International Unit of antitoxin per ml. (ii) Make a dilution of Standard Toxin in which 0.1 Lo... Antitoxin with 0.1 Lo dose of diluted Standard Toxin and combine 0.1 International Unit of Standard...

9 CFR 113.108 - Clostridium Novyi Bacterin-Toxoid.

Code of Federal Regulations, 2013 CFR

2013-01-01

... which reacts with Lo and L+ doses of Standard Toxin according to their definitions. (ii) Lo dose. The... 0.1 International Unit of antitoxin per ml. (ii) Make a dilution of Standard Toxin in which 0.1 Lo... Antitoxin with 0.1 Lo dose of diluted Standard Toxin and combine 0.1 International Unit of Standard...

75 FR 54031 - Approval and Promulgation of Implementation Plans; Designation of Areas for Air Quality Planning...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-09-03

... below. FOR FURTHER INFORMATION CONTACT: Doris Lo, EPA Region IX, (415) 972- 3959, lo[email protected] Meredith Kurpius, EPA Region 9, Air Quality Assessment Office, to Doris Lo, EPA Region 9, Air Planning... Officer, GBUAPCD, to Doris Lo, EPA Region 9, Air Planning Office, with attachments. The Coso Operating...

9 CFR 113.108 - Clostridium Novyi Bacterin-Toxoid.

Code of Federal Regulations, 2011 CFR

2011-01-01

... which reacts with Lo and L+ doses of Standard Toxin according to their definitions. (ii) Lo dose. The... 0.1 International Unit of antitoxin per ml. (ii) Make a dilution of Standard Toxin in which 0.1 Lo... Antitoxin with 0.1 Lo dose of diluted Standard Toxin and combine 0.1 International Unit of Standard...

9 CFR 113.108 - Clostridium Novyi Bacterin-Toxoid.

Code of Federal Regulations, 2012 CFR

2012-01-01

... which reacts with Lo and L+ doses of Standard Toxin according to their definitions. (ii) Lo dose. The... 0.1 International Unit of antitoxin per ml. (ii) Make a dilution of Standard Toxin in which 0.1 Lo... Antitoxin with 0.1 Lo dose of diluted Standard Toxin and combine 0.1 International Unit of Standard...

Substrate specificity effects of lipoxygenase products and inhibitors on soybean lipoxygenase-1.

PubMed

Wecksler, Aaron T; Garcia, Natalie K; Holman, Theodore R

2009-09-15

Recently, it has been shown that lipoxygenase (LO) products affect the substrate specificity of human 15-LO. In the current paper, we demonstrate that soybean LO-1 (sLO-1) is not affected by its own products, however, inhibitors which bind the allosteric site, oleyl sulfate (OS) and palmitoleyl sulfate (PS), not only lower catalytic activity, but also change the substrate specificity, by increasing the arachidonic acid (AA)/linoleic acid (LA) ratio to 4.8 and 4.0, respectively. The fact that LO inhibitors can lower activity and also change the LO product ratio is a new concept in lipoxygenase inhibition, where the goal is to not only reduce the catalytic activity but also alter substrate selectivity towards a physiologically beneficial product.

Pressure-induced structural change in liquid GeI4.

PubMed

Fuchizaki, Kazuhiro; Nishimura, Hironori; Hase, Takaki; Saitoh, Hiroyuki

2017-12-27

The similarity in the shape of the melting curve of GeI 4 to that of SnI 4 suggests that a liquid-liquid transition as observed in liquid SnI 4 is also expected to occur in liquid GeI 4 . Because the slope of the melting curve of GeI 4 abruptly changes at around 3 GPa, in situ synchrotron diffraction measurements were conducted to examine closely the structural changes upon compression at around 3 GPa. The reduced radial distribution functions of the high- and low-pressure liquid states of GeI 4 share the same feature inherent in the high-pressure (high-density) and low-pressure (low-density) radial distribution functions of liquid SnI 4 . This feature allows us to introduce local order parameters that we may use to observe the transition. Unlike the transition in liquid SnI 4 , the transition from the low-pressure to the high-pressure structure seems sluggish. We speculate that the liquid-liquid critical point of GeI 4 is no longer a thermodynamically stable state and is slightly located below the melting curve. As a result, the structural change is said to be a crossover rather than a transition. The behavior of the local-order parameters implies a metastable extension of the liquid-liquid phase boundary with a negative slope.

A Molecular Dynamics Study of the Structure-Dynamics Relationships of Supercooled Liquids and Glasses

NASA Astrophysics Data System (ADS)

Soklaski, Ryan

Central to the field of condensed matter physics is a decades old outstanding problem in the study of glasses -- namely explaining the extreme slowing of dynamics in a liquid as it is supercooled towards the so-called glass transition. Efforts to universally describe the stretched relaxation processes and heterogeneous dynamics that characteristically develop in supercooled liquids remain divided in both their approaches and successes. Towards this end, a consensus on the role that atomic and molecular structures play in the liquid is even more tenuous. However, mounting material science research efforts have culminated to reveal that the vast diversity of metallic glass species and their properties are rooted in an equally-broad set of structural archetypes. Herein lies the motivation of this dissertation: the detailed information available regarding the structure-property relationships of metallic glasses provides a new context in which one can study the evolution of a supercooled liquid by utilizing a structural motif that is known to dominate the glass. Cu64Zr36 is a binary alloy whose good glass-forming ability and simple composition makes it a canonical material to both empirical and numerical studies. Here, we perform classical molecular dynamics simulations and conduct a comprehensive analysis of the dynamical regimes of liquid Cu64Zr36, while focusing on the roles played by atomic icosahedral ordering -- a structural motif which ultimately percolates the glass' structure. Large data analysis techniques are leveraged to obtain uniquely detailed structural and dynamical information in this context. In doing so, we develop the first account of the origin of icosahedral order in this alloy, revealing deep connections between this incipient structural ordering, frustration-limited domain theory, and recent important empirical findings that are relevant to the nature of metallic liquids at large. Furthermore, important dynamical landmarks such as the breakdown of the Stokes-Einstein relationship, the decoupling of particle diffusivities, and the development of general "glassy" relaxation features are found to coincide with successive manifestation of icosahedral ordering that arise as the liquid is supercooled. Remarkably, we detect critical-like features in the growth of the icosahedron network, with signatures that suggest that a liquid-liquid phase transition may occur in the deeply supercooled regime to precede glass formation. Such a transition is predicted to occur in many supercooled liquids, although explicit evidence of this phenomenon in realistic systems is scarce. Ultimately this work concludes that icosahedral order characterizes all dynamical regimes of Cu64Zr 36, demonstrating the importance and utility of studying supercooled liquids in the context of locally-preferred structure. More broadly, it serves to confirm and inform recent theoretical and empirical findings that are central to understanding the physics underlying the glass transition.

75 FR 56538 - Air Products and Chemicals, Inc.; Analysis of Proposed Agreement Containing Consent Orders to Aid...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-09-16

... certain regional markets in the United States for the manufacture and sale of bulk liquid oxygen and bulk... the United States that produce liquid atmospheric gases, including liquid oxygen and liquid nitrogen.... For most of these applications, there is no viable substitute for the use of oxygen or nitrogen...

Synergism of magnesium deficiency and nickel toxicity in growth and bone development

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kenney, M.A.; Dicker, A.; McCoy, H.

1991-03-15

The authors examined effects of Mg level and of Ni in diets of growing rats. Male rats weighing 100 g were fed a diet adequate, low or high in Mg and adequate in other nutrients. After a week, LoMg and HiMg groups were sub-divided and fed 0 or 500 ppm Ni for the remaining 7 weeks. Animals fed LoMg+Ni gained less than half as much weight and ate about 75% as much ration as other groups. Food efficiency was reduced due to added Ni for LoMg. Many measurements related to growth showed this interaction of Mg and Ni, with lowmore » values in LoMg+Ni group, compared with all others. Spleen and thymus wt/g body wt increased in LoMg+Ni, while femurs and vertebrae were lightest, contained the least ash, and withstood the least force before breaking in a 3-point flexure test. However, because femurs of LoMg+Ni rats were small, the calculated breaking stress was greatest. Bones of LoMg rats supported a greater load than those of Ctl or HiMg, but breaking stress of femur was similar at all 3 levels of Mg when Ni was not fed. Overall, the LoMg diet produced little evidence of deficiency except when Ni was added; conversely, dietary Ni was much less toxic with HiMg than with LoMg.« less

9 CFR 113.109 - Clostridium Sordellii Bacterin-Toxoid.

Code of Federal Regulations, 2012 CFR

2012-01-01

... which reacts with Lo and L+ doses of Standard Toxin according to their definitions. (ii) Lo dose. The... a dilution of Standard Toxin in which 1.0 Lo dose is contained in a volume of 1 ml or less. Make a...) Combine 1.0 International Unit Standard Antitoxin with 1.0 Lo dose of diluted Standard Toxin and combine 1...

9 CFR 113.109 - Clostridium Sordellii Bacterin-Toxoid.

Code of Federal Regulations, 2011 CFR

2011-01-01

... which reacts with Lo and L+ doses of Standard Toxin according to their definitions. (ii) Lo dose. The... a dilution of Standard Toxin in which 1.0 Lo dose is contained in a volume of 1 ml or less. Make a...) Combine 1.0 International Unit Standard Antitoxin with 1.0 Lo dose of diluted Standard Toxin and combine 1...

9 CFR 113.109 - Clostridium Sordellii Bacterin-Toxoid.

Code of Federal Regulations, 2014 CFR

2014-01-01

... which reacts with Lo and L+ doses of Standard Toxin according to their definitions. (ii) Lo dose. The... a dilution of Standard Toxin in which 1.0 Lo dose is contained in a volume of 1 ml or less. Make a...) Combine 1.0 International Unit Standard Antitoxin with 1.0 Lo dose of diluted Standard Toxin and combine 1...

9 CFR 113.109 - Clostridium Sordellii Bacterin-Toxoid.

Code of Federal Regulations, 2013 CFR

2013-01-01

... which reacts with Lo and L+ doses of Standard Toxin according to their definitions. (ii) Lo dose. The... a dilution of Standard Toxin in which 1.0 Lo dose is contained in a volume of 1 ml or less. Make a...) Combine 1.0 International Unit Standard Antitoxin with 1.0 Lo dose of diluted Standard Toxin and combine 1...

The Sublime Corpse in Gertrudis Gomez de Avellaneda's Women's Journal "Album Cubano de lo Bueno y lo Bello" (1860)

ERIC Educational Resources Information Center

LaGreca, Nancy

2009-01-01

This article examines Gertrudis Gomez de Avellaneda's choice to include articles depicting the advanced decay of cadavers, which are simultaneously horrible and awesome, in her women's periodical "Album Cubano de lo Bueno y lo Bello". Background on Avellaneda's biography, women's print culture, and theories of the sublime provide a frame for the…

Cytochrome P450 and Lipoxygenase Metabolites on Renal Function

PubMed Central

Imig, John D.; Hye Khan, Md. Abdul

2018-01-01

Arachidonic acid metabolites have a myriad of biological actions including effects on the kidney to alter renal hemodynamics and tubular transport processes. Cyclooxygenase metabolites are products of an arachidonic acid enzymatic pathway that has been extensively studied in regards to renal function. Two lesser-known enzymatic pathways of arachidonic acid metabolism are the lipoxygenase (LO) and cytochrome P450 (CYP) pathways. The importance of LO and CYP metabolites to renal hemodynamics and tubular transport processes is now being recognized. LO and CYP metabolites have actions to alter renal blood flow and glomerular filtration rate. Proximal and distal tubular sodium transport and fluid and electrolyte homeostasis are also significantly influenced by renal CYP and LO levels. Metabolites of the LO and CYP pathways also have renal actions that influence renal inflammation, proliferation, and apoptotic processes at vascular and epithelial cells. These renal LO and CYP pathway actions occur through generation of specific metabolites and cell-signaling mechanisms. Even though the renal physiological importance and actions for LO and CYP metabolites are readily apparent, major gaps remain in our understanding of these lipid mediators to renal function. Future studies will be needed to fill these major gaps regarding LO and CYP metabolites on renal function. PMID:26756638

Modeling the Energy Performance of LoRaWAN

PubMed Central

2017-01-01

LoRaWAN is a flagship Low-Power Wide Area Network (LPWAN) technology that has highly attracted much attention from the community in recent years. Many LoRaWAN end-devices, such as sensors or actuators, are expected not to be powered by the electricity grid; therefore, it is crucial to investigate the energy consumption of LoRaWAN. However, published works have only focused on this topic to a limited extent. In this paper, we present analytical models that allow the characterization of LoRaWAN end-device current consumption, lifetime and energy cost of data delivery. The models, which have been derived based on measurements on a currently prevalent LoRaWAN hardware platform, allow us to quantify the impact of relevant physical and Medium Access Control (MAC) layer LoRaWAN parameters and mechanisms, as well as Bit Error Rate (BER) and collisions, on energy performance. Among others, evaluation results show that an appropriately configured LoRaWAN end-device platform powered by a battery of 2400 mAh can achieve a 1-year lifetime while sending one message every 5 min, and an asymptotic theoretical lifetime of 6 years for infrequent communication. PMID:29035347

Modeling the Energy Performance of LoRaWAN.

PubMed

Casals, Lluís; Mir, Bernat; Vidal, Rafael; Gomez, Carles

2017-10-16

LoRaWAN is a flagship Low-Power Wide Area Network (LPWAN) technology that has highly attracted much attention from the community in recent years. Many LoRaWAN end-devices, such as sensors or actuators, are expected not to be powered by the electricity grid; therefore, it is crucial to investigate the energy consumption of LoRaWAN. However, published works have only focused on this topic to a limited extent. In this paper, we present analytical models that allow the characterization of LoRaWAN end-device current consumption, lifetime and energy cost of data delivery. The models, which have been derived based on measurements on a currently prevalent LoRaWAN hardware platform, allow us to quantify the impact of relevant physical and Medium Access Control (MAC) layer LoRaWAN parameters and mechanisms, as well as Bit Error Rate (BER) and collisions, on energy performance. Among others, evaluation results show that an appropriately configured LoRaWAN end-device platform powered by a battery of 2400 mAh can achieve a 1-year lifetime while sending one message every 5 min, and an asymptotic theoretical lifetime of 6 years for infrequent communication.

Ab-initio molecular dynamics simulations of liquid Hg-Pb alloys

NASA Astrophysics Data System (ADS)

Sharma, Nalini; Thakur, Anil; Ahluwalia, P. K.

2014-04-01

Ab-initio molecular dynamics simulations are performed to study the structural properties of liquid Hg-Pb alloys. The interatomic interactions are described by ab-initio pseudopotentials given by Troullier and Martins. Three liquid Hg-Pb mixtures (Hg30Pb70, Hg50Pb50 and Hg90Pb10) at 600K are considered. The radial distribution function g(r) and structure factor S(q) of considered alloys are compared with respective experimental results for liquid Hg (l-Hg) and lead (l-Pb). The radial distribution function g(r) shows the presence of short range order in the systems considered. Smooth curves of Bhatia-Thornton partial structure factors factor shows the presence of liquid state in the considered three alloys. Among the all considered alloys, Hg50Pb50 alloy shows presence of more chemical ordering and presence of hetero-coordination.

Molecular recognition in chiral smectic liquid crystals: the effect of core-core interactions and chirality transfer on polar order.

PubMed

Lemieux, Robert P

2007-12-01

This critical review focuses on the induction of polar order in smectic liquid crystal phases by dopants with axially chiral cores, and should be of interest to all practitioners of supramolecular chemistry. The variations in polarization power of these dopants with the core structure of the liquid crystal hosts is a manifestation of molecular recognition that reflects the nanosegregation of aromatic cores from paraffinic side-chains in smectic phases, and the collective effect of core-core interactions that enable the propagation of chiral perturbations.