System design description of forced-convection molten-salt corrosion loops MSR-FCL-3 and MSR-FCL-4
DOE Office of Scientific and Technical Information (OSTI.GOV)
Huntley, W.R.; Silverman, M.D.
1976-11-01
Molten-salt corrosion loops MSR-FCL-3 and MSR-FCL-4 are high-temperature test facilities designed to evaluate corrosion and mass transfer of modified Hastelloy N alloys for future use in Molten-Salt Breeder Reactors. Salt is circulated by a centrifugal sump pump to evaluate material compatibility with LiF-BeF/sub 2/-ThF/sub 4/-UF/sub 4/ fuel salt at velocities up to 6 m/s (20 fps) and at salt temperatures from 566 to 705/sup 0/C (1050 to 1300/sup 0/F). The report presents the design description of the various components and systems that make up each corrosion facility, such as the salt pump, corrosion specimens, salt piping, main heaters, salt coolers,more » salt sampling equipment, and helium cover-gas system, etc. The electrical systems and instrumentation and controls are described, and operational procedures, system limitations, and maintenance philosophy are discussed.« less
Molten Chloride Salts for Heat Transfer in Nuclear Systems
NASA Astrophysics Data System (ADS)
Ambrosek, James Wallace
2011-12-01
A forced convection loop was designed and constructed to examine the thermal-hydraulic performance of molten KCl-MgCl2 (68-32 at %) salt for use in nuclear co-generation facilities. As part of this research, methods for prediction of the thermo-physical properties of salt mixtures for selection of the coolant salt were studied. In addition, corrosion studies of 10 different alloys were exposed to the KCl-MgCl2 to determine a suitable construction material for the loop. Using experimental data found in literature for unary and binary salt systems, models were found, or developed to extrapolate the available experimental data to unstudied salt systems. These property models were then used to investigate the thermo-physical properties of the LINO3-NaNO3-KNO 3-Ca(NO3), system used in solar energy applications. Using these models, the density, viscosity, adiabatic compressibility, thermal conductivity, heat capacity, and melting temperatures of higher order systems can be approximated. These models may be applied to other molten salt systems. Coupons of 10 different alloys were exposed to the chloride salt for 100 hours at 850°C was undertaken to help determine with which alloy to construct the loop. Of the alloys exposed, Haynes 230 had the least amount of weight loss per area. Nickel and Hastelloy N performed best based on maximum depth of attack. Inconel 625 and 718 had a nearly uniform depletion of Cr from the surface of the sample. All other alloys tested had depletion of Cr along the grain boundaries. The Nb in Inconel 625 and 718 changed the way the Cr is depleted in these alloys. Grain-boundary engineering (GBE) of Incoloy 800H improved the corrosion resistance (weight loss and maximum depth of attack) by nearly 50% as compared to the as-received Incoloy 800H sample. A high temperature pump, thermal flow meter, and pressure differential device was designed, constructed and tested for use in the loop, The heat transfer of the molten chloride salt was found to
DOE Office of Scientific and Technical Information (OSTI.GOV)
Yoder Jr, Graydon L; Aaron, Adam M; Cunningham, Richard Burns
2014-01-01
The need for high-temperature (greater than 600 C) energy exchange and delivery systems is significantly increasing as the world strives to improve energy efficiency and develop alternatives to petroleum-based fuels. Liquid fluoride salts are one of the few energy transport fluids that have the capability of operating at high temperatures in combination with low system pressures. The Fluoride Salt-Cooled High-Temperature Reactor design uses fluoride salt to remove core heat and interface with a power conversion system. Although a significant amount of experimentation has been performed with these salts, specific aspects of this reactor concept will require experimental confirmation during themore » development process. The experimental facility described here has been constructed to support the development of the Fluoride Salt Cooled High Temperature Reactor concept. The facility is capable of operating at up to 700 C and incorporates a centrifugal pump to circulate FLiNaK salt through a removable test section. A unique inductive heating technique is used to apply heat to the test section, allowing heat transfer testing to be performed. An air-cooled heat exchanger removes added heat. Supporting loop infrastructure includes a pressure control system; trace heating system; and a complement of instrumentation to measure salt flow, temperatures, and pressures around the loop. The initial experiment is aimed at measuring fluoride salt heat transfer inside a heated pebble bed similar to that used for the core of the pebble bed advanced high-temperature reactor. This document describes the details of the loop design, auxiliary systems used to support the facility, the inductive heating system, and facility capabilities.« less
Freie, Angela Bourbon; Ferrato, Francine; Carrière, Frédéric; Lowe, Mark E.
2013-01-01
In a previous study, we demonstrated that the β5′-loop in the C-terminal domain of human pancreatic triglyceride lipase (hPTL) makes a major contribution in the function of hPTL (Chahinian et al. (2002) Biochemistry 41, 13725–13735). In the present study, we characterized the contribution of three residues in the β5′-loop, Val-407, Ile-408, and Leu-412, to the function of hPTL. By substituting charged residues, aspartate or lysine, in these positions, we altered the hydrophilic to lipophilic ratio of the β5′-loop. Each of the mutants was expressed, purified, and characterized for activity and binding with both monolayers and emulsions and for binding to colipase. Experiments with monolayers and with emulsions suggested that the interaction of hPTL with a phospholipid monolayer differs from the interaction of the hPTL-colipase complex with a dicaprin monolayer or a triglyceride emulsion (i.e. neutral lipids). Val-407, Ile-408, and Leu-412 make major contributions to interactions with monolayers, whereas only Val-407 and Ile-408 appear essential for activity on triglyceride emulsions in the presence of bile salt micelles. In solutions of taurodeoxycholate at micellar concentrations, a major effect of the β5′-loop mutations is to change the interaction between hPTL and colipase. These observations support a major contribution of residues in the β5′-loop in the function of hPTL and suggest that a third partner, bile salt micelles or the lipid interface or both, influence the binding of colipase and hPTL through interactions with the β5′-loop. PMID:16431912
Mechanical response and microprocesses of reconsolidating crushed salt at elevated temperature
Broome, S. T.; Bauer, S. J.; Hansen, F. D.; ...
2015-09-14
Design, analysis and performance assessment of potential salt repositories for heat-generating nuclear waste require knowledge of thermal, mechanical, and fluid transport properties of reconsolidating granular salt. So, to inform salt repository evaluations, we have undertaken an experimental program to determine Bulk and Young’s moduli and Poisson’s ratio of reconsolidated granular salt as a function of porosity and temperature and to establish the deformational processes by which the salt reconsolidates. Our tests were conducted at 100, 175, and 250 °C. In hydrostatic tests, confining pressure is increased to 20 MPa with periodic unload/reload loops to determine K. Volume strain increases withmore » increasing temperature. In shear tests at 2.5 and 5 MPa confining pressure, after confining pressure is applied, the crushed salt is subjected to a differential stress, with periodic unload/reload loops to determine E and ν. At predetermined differential stress levels the stress is held constant and the salt consolidates. Displacement gages mounted on the samples show little lateral deformation until the samples reach a porosity of ~10 %. Interestingly, vapor is vented only for 250 °C tests and condenses at the vent port. It is hypothesized that the brine originates from fluid inclusions, which were made accessible by heating and intragranular deformational processes including decrepitation. Furthermore, identification and documentation of consolidation processes are inferred from optical and scanning electron microstructural observations. As a result, densification at low porosity is enhanced by water film on grain boundaries that enables solution-precipitation phenomena.« less
NASA Astrophysics Data System (ADS)
Roche, M.
A solar thermal power plant using fused salt as the heat transfer fluid for steam power generation is analyzed for the feasibility of economic operation. The salt is also stored in a tank reservoir for maintaining the primary heat loop at temperatures high enough for the salts to remain liquid, and also to provide reserve power for the steam generator. Initial studies were with eutectic (hitec) salt comprising Na, KOH, and nitrites melting at 146 C, and further studies were performed employing draw salt, which has no nitrite, is more stable at high temperature, and melts at 225 C. The use of draw salt was found to allow a 5 percent reduction in storage capacity. Further examinations of the effects of the hitec salts on corrosion and composition degradation at high temperatures are indicated. The molten salt system is projected to offer an efficiency of 26 percent.
Microbial Abundances in Salt Marsh Soils: A Molecular Approach for Small Spatial Scales
NASA Astrophysics Data System (ADS)
Granse, Dirk; Mueller, Peter; Weingartner, Magdalena; Hoth, Stefan; Jensen, Kai
2016-04-01
The rate of biological decomposition greatly determines the carbon sequestration capacity of salt marshes. Microorganisms are involved in the decomposition of biomass and the rate of decomposition is supposed to be related to microbial abundance. Recent studies quantified microbial abundance by means of quantitative polymerase chain reaction (QPCR), a method that also allows determining the microbial community structure by applying specific primers. The main microbial community structure can be determined by using primers specific for 16S rRNA (Bacteria) and 18S rRNA (Fungi) of the microbial DNA. However, the investigation of microbial abundance pattern at small spatial scales, such as locally varying abiotic conditions within a salt-marsh system, requires high accuracy in DNA extraction and QPCR methods. Furthermore, there is evidence that a single extraction may not be sufficient to reliably quantify rRNA gene copies. The aim of this study was to establish a suitable DNA extraction method and stable QPCR conditions for the measurement of microbial abundances in semi-terrestrial environments. DNA was extracted from two soil samples (top WE{5}{cm}) by using the PowerSoil DNA Extraction Kit (Mo Bio Laboratories, Inc., Carlsbad, CA) and applying a modified extraction protocol. The DNA extraction was conducted in four consecutive DNA extraction loops from three biological replicates per soil sample by reusing the PowerSoil bead tube. The number of Fungi and Bacteria rRNA gene copies of each DNA extraction loop and a pooled DNA solution (extraction loop 1 - 4) was measured by using the QPCR method with taxa specific primer pairs (Bacteria: B341F, B805R; Fungi: FR1, FF390). The DNA yield of the replicates varied at DNA extraction loop 1 between WE{25 and 85}{ng
Salt bridge as a gatekeeper against partial unfolding.
Hinzman, Mark W; Essex, Morgan E; Park, Chiwook
2016-05-01
Salt bridges are frequently observed in protein structures. Because the energetic contribution of salt bridges is strongly dependent on the environmental context, salt bridges are believed to contribute to the structural specificity rather than the stability. To test the role of salt bridges in enhancing structural specificity, we investigated the contribution of a salt bridge to the energetics of native-state partial unfolding in a cysteine-free version of Escherichia coli ribonuclease H (RNase H*). Thermolysin cleaves a protruding loop of RNase H(*) through transient partial unfolding under native conditions. Lys86 and Asp108 in RNase H(*) form a partially buried salt bridge that tethers the protruding loop. Investigation of the global stability of K86Q/D108N RNase H(*) showed that the salt bridge does not significantly contribute to the global stability. However, K86Q/D108N RNase H(*) is greatly more susceptible to proteolysis by thermolysin than wild-type RNase H(*) is. The free energy for partial unfolding determined by native-state proteolysis indicates that the salt bridge significantly increases the energy for partial unfolding by destabilizing the partially unfolded form. Double mutant cycles with single and double mutations of the salt bridge suggest that the partially unfolded form is destabilized due to a significant decrease in the interaction energy between Lys86 and Asp108 upon partial unfolding. This study demonstrates that, even in the case that a salt bridge does not contribute to the global stability, the salt bridge may function as a gatekeeper against partial unfolding that disturbs the optimal geometry of the salt bridge. © 2016 The Protein Society.
Advanced Instrumentation for Molten Salt Flow Measurements at NEXT
NASA Astrophysics Data System (ADS)
Tuyishimire, Olive
2017-09-01
The Nuclear Energy eXperiment Testing (NEXT) Lab at Abilene Christian University is building a Molten Salt Loop to help advance the technology of molten salt reactors (MSR). NEXT Lab's aim is to be part of the solution for the world's top challenges by providing safe, clean, and inexpensive energy, clean water and medical Isotopes. Measuring the flow rate of the molten salt in the loop is essential to the operation of a MSR. Unfortunately, there is no flow meter that can operate in the high temperature and corrosive environment of a molten salt. The ultrasonic transit time method is proposed as one way to measure the flow rate of high temperature fluids. Ultrasonic flow meter uses transducers that send and receive acoustic waves and convert them into electrical signals. Initial work presented here focuses on the setup of ultrasonic transducers. This presentation is the characterization of the pipe-fluid system with water as a baseline for future work.
Tritium Management Loop Design Status
DOE Office of Scientific and Technical Information (OSTI.GOV)
Rader, Jordan D.; Felde, David K.; McFarlane, Joanna
This report summarizes physical, chemical, and engineering analyses that have been done to support the development of a test loop to study tritium migration in 2LiF-BeF2 salts. The loop will operate under turbulent flow and a schematic of the apparatus has been used to develop a model in Mathcad to suggest flow parameters that should be targeted in loop operation. The introduction of tritium into the loop has been discussed as well as various means to capture or divert the tritium from egress through a test assembly. Permeation was calculated starting with a Modelica model for a transport through amore » nickel window into a vacuum, and modifying it for a FLiBe system with an argon sweep gas on the downstream side of the permeation interface. Results suggest that tritium removal with a simple tubular permeation device will occur readily. Although this system is idealized, it suggests that rapid measurement capability in the loop may be necessary to study and understand tritium removal from the system.« less
Ganther, Jr., Kenneth R.; Snapp, Lowell D.
2002-09-10
A flux locked loop for providing an electrical feedback signal, the flux locked loop employing radio-frequency components and technology to extend the flux modulation frequency and tracking loop bandwidth. The flux locked loop of the present invention has particularly useful application in read-out electronics for DC SQUID magnetic measurement systems, in which case the electrical signal output by the flux locked loop represents an unknown magnetic flux applied to the DC SQUID.
Storm water monitoring along loop 202 and Salt River.
DOT National Transportation Integrated Search
2010-10-01
A comprehensive research program for the characterization of storm water runoff from an Arizona : highway was conducted from January through December 2007. The study area covered a portion of : the Loop 202 freeway west of Mesa Drive to a retention b...
Applying a Consumer Behavior Lens to Salt Reduction Initiatives.
Regan, Áine; Kent, Monique Potvin; Raats, Monique M; McConnon, Áine; Wall, Patrick; Dubois, Lise
2017-08-18
Reformulation of food products to reduce salt content has been a central strategy for achieving population level salt reduction. In this paper, we reflect on current reformulation strategies and consider how consumer behavior determines the ultimate success of these strategies. We consider the merits of adopting a 'health by stealth', silent approach to reformulation compared to implementing a communications strategy which draws on labeling initiatives in tandem with reformulation efforts. We end this paper by calling for a multi-actor approach which utilizes co-design, participatory tools to facilitate the involvement of all stakeholders, including, and especially, consumers, in making decisions around how best to achieve population-level salt reduction.
N -loop running should be combined with N -loop matching
NASA Astrophysics Data System (ADS)
Braathen, Johannes; Goodsell, Mark D.; Krauss, Manuel E.; Opferkuch, Toby; Staub, Florian
2018-01-01
We investigate the high-scale behavior of Higgs sectors beyond the Standard Model, pointing out that the proper matching of the quartic couplings before applying the renormalization group equations (RGEs) is of crucial importance for reliable predictions at larger energy scales. In particular, the common practice of leading-order parameters in the RGE evolution is insufficient to make precise statements on a given model's UV behavior, typically resulting in uncertainties of many orders of magnitude. We argue that, before applying N -loop RGEs, a matching should even be performed at N -loop order in contrast to common lore. We show both analytical and numerical results where the impact is sizable for three minimal extensions of the Standard Model: a singlet extension, a second Higgs doublet and finally vector-like quarks. We highlight that the known two-loop RGEs tend to moderate the running of their one-loop counterparts, typically delaying the appearance of Landau poles. For the addition of vector-like quarks we show that the complete two-loop matching and RGE evolution hints at a stabilization of the electroweak vacuum at high energies, in contrast to results in the literature.
Applying a Consumer Behavior Lens to Salt Reduction Initiatives
Potvin Kent, Monique; Raats, Monique M.; McConnon, Áine; Wall, Patrick; Dubois, Lise
2017-01-01
Reformulation of food products to reduce salt content has been a central strategy for achieving population level salt reduction. In this paper, we reflect on current reformulation strategies and consider how consumer behavior determines the ultimate success of these strategies. We consider the merits of adopting a ‘health by stealth’, silent approach to reformulation compared to implementing a communications strategy which draws on labeling initiatives in tandem with reformulation efforts. We end this paper by calling for a multi-actor approach which utilizes co-design, participatory tools to facilitate the involvement of all stakeholders, including, and especially, consumers, in making decisions around how best to achieve population-level salt reduction. PMID:28820449
Han, Nanyu; Mu, Yuguang
2013-01-01
Neuraminidase (NA) of influenza is a key target for antiviral inhibitors, and the 150-cavity in group-1 NA provides new insight in treating this disease. However, NA of 2009 pandemic influenza (09N1) was found lacking this cavity in a crystal structure. To address the issue of flexibility of the 150-loop, Hamiltonian replica exchange molecular dynamics simulations were performed on different groups of NAs. Free energy landscape calculated based on the volume of 150-cavity indicates that 09N1 prefers open forms of 150-loop. The turn A (residues 147-150) of the 150-loop is discovered as the most dynamical motif which induces the inter-conversion of this loop among different conformations. In the turn A, the backbone dynamic of residue 149 is highly related with the shape of 150-loop, thus can function as a marker for the conformation of 150-loop. As a contrast, the closed conformation of 150-loop is more energetically favorable in N2, one of group-2 NAs. The D147-H150 salt bridge is found having no correlation with the conformation of 150-loop. Instead the intimate salt bridge interaction between the 150 and 430 loops in N2 variant contributes the stabilizing factor for the closed form of 150-loop. The clustering analysis elaborates the structural plasticity of the loop. This enhanced sampling simulation provides more information in further structural-based drug discovery on influenza virus.
Han, Nanyu; Mu, Yuguang
2013-01-01
Neuraminidase (NA) of influenza is a key target for antiviral inhibitors, and the 150-cavity in group-1 NA provides new insight in treating this disease. However, NA of 2009 pandemic influenza (09N1) was found lacking this cavity in a crystal structure. To address the issue of flexibility of the 150-loop, Hamiltonian replica exchange molecular dynamics simulations were performed on different groups of NAs. Free energy landscape calculated based on the volume of 150-cavity indicates that 09N1 prefers open forms of 150-loop. The turn A (residues 147–150) of the 150-loop is discovered as the most dynamical motif which induces the inter-conversion of this loop among different conformations. In the turn A, the backbone dynamic of residue 149 is highly related with the shape of 150-loop, thus can function as a marker for the conformation of 150-loop. As a contrast, the closed conformation of 150-loop is more energetically favorable in N2, one of group-2 NAs. The D147-H150 salt bridge is found having no correlation with the conformation of 150-loop. Instead the intimate salt bridge interaction between the 150 and 430 loops in N2 variant contributes the stabilizing factor for the closed form of 150-loop. The clustering analysis elaborates the structural plasticity of the loop. This enhanced sampling simulation provides more information in further structural-based drug discovery on influenza virus. PMID:23593372
Atomistic Simulation of Interstitial Dislocation Loop Evolution under Applied Stresses in BCC Iron
DOE Office of Scientific and Technical Information (OSTI.GOV)
Long, Xue Hao; Wang, Dong; Setyawan, Wahyu
Evolution of an interstitial 1/2⟨111⟩ dislocation loop under tensile, shear, and torsion stresses is studied with molecular statics method. Under a tensile stress, the dependence of ultimate tensile strength on size of loop is calculated. The formation of small shear loops around the initial prismatic loop is confirmed as an intermediate state to form the final dislocation network. Under a shear stress, the rotation of a loop is observed not only by a change of the habit plane but also through a transformation between a shear and a prismatic loop. Under torsion, a perfect BCC crystal may undergo a BCCmore » to FCC or BCC to HCP transformation. The present work indicates that a 1/2⟨111⟩ loop can delay these transformations, resulting in the formation of micro-crack on the surface.« less
DOE Office of Scientific and Technical Information (OSTI.GOV)
Piyush Sabharwall; Matt Ebner; Manohar Sohal
2010-03-01
Considerable amount of work is going on regarding the development of high temperature liquid salts technology to meet future process needs of Next Generation Nuclear Plant. This report identifies the important characteristics and concerns of high temperature molten salts (with lesson learned at University of Wisconsin-Madison, Molten Salt Program) and provides some possible recommendation for future work
Cooling molten salt reactors using "gas-lift"
NASA Astrophysics Data System (ADS)
Zitek, Pavel; Valenta, Vaclav; Klimko, Marek
2014-08-01
This study briefly describes the selection of a type of two-phase flow, suitable for intensifying the natural flow of nuclear reactors with liquid fuel - cooling mixture molten salts and the description of a "Two-phase flow demonstrator" (TFD) used for experimental study of the "gas-lift" system and its influence on the support of natural convection. The measuring device and the application of the TDF device is described. The work serves as a model system for "gas-lift" (replacing the classic pump in the primary circuit) for high temperature MSR planned for hydrogen production. An experimental facility was proposed on the basis of which is currently being built an experimental loop containing the generator, separator bubbles and necessary accessories. This loop will model the removal of gaseous fission products and tritium. The cleaning of the fuel mixture of fluoride salts eliminates problems from Xenon poisoning in classical reactors.
Applying Computer Models to Realize Closed-Loop Neonatal Oxygen Therapy.
Morozoff, Edmund; Smyth, John A; Saif, Mehrdad
2017-01-01
Within the context of automating neonatal oxygen therapy, this article describes the transformation of an idea verified by a computer model into a device actuated by a computer model. Computer modeling of an entire neonatal oxygen therapy system can facilitate the development of closed-loop control algorithms by providing a verification platform and speeding up algorithm development. In this article, we present a method of mathematically modeling the system's components: the oxygen transport within the patient, the oxygen blender, the controller, and the pulse oximeter. Furthermore, within the constraints of engineering a product, an idealized model of the neonatal oxygen transport component may be integrated effectively into the control algorithm of a device, referred to as the adaptive model. Manual and closed-loop oxygen therapy performance were defined in this article by 3 criteria in the following order of importance: percent duration of SpO2 spent in normoxemia (target SpO2 ± 2.5%), hypoxemia (less than normoxemia), and hyperoxemia (more than normoxemia); number of 60-second periods <85% SpO2 and >95% SpO2; and number of manual adjustments. Results from a clinical evaluation that compared the performance of 3 closed-loop control algorithms (state machine, proportional-integral-differential, and adaptive model) with manual oxygen therapy on 7 low-birth-weight ventilated preterm babies, are presented. Compared with manual therapy, all closed-loop control algorithms significantly increased the patients' duration in normoxemia and reduced hyperoxemia (P < 0.05). The number of manual adjustments was also significantly reduced by all of the closed-loop control algorithms (P < 0.05). Although the performance of the 3 control algorithms was equivalent, it is suggested that the adaptive model, with its ease of use, may have the best utility.
Palkowski, Marek; Bielecki, Wlodzimierz
2017-06-02
RNA secondary structure prediction is a compute intensive task that lies at the core of several search algorithms in bioinformatics. Fortunately, the RNA folding approaches, such as the Nussinov base pair maximization, involve mathematical operations over affine control loops whose iteration space can be represented by the polyhedral model. Polyhedral compilation techniques have proven to be a powerful tool for optimization of dense array codes. However, classical affine loop nest transformations used with these techniques do not optimize effectively codes of dynamic programming of RNA structure predictions. The purpose of this paper is to present a novel approach allowing for generation of a parallel tiled Nussinov RNA loop nest exposing significantly higher performance than that of known related code. This effect is achieved due to improving code locality and calculation parallelization. In order to improve code locality, we apply our previously published technique of automatic loop nest tiling to all the three loops of the Nussinov loop nest. This approach first forms original rectangular 3D tiles and then corrects them to establish their validity by means of applying the transitive closure of a dependence graph. To produce parallel code, we apply the loop skewing technique to a tiled Nussinov loop nest. The technique is implemented as a part of the publicly available polyhedral source-to-source TRACO compiler. Generated code was run on modern Intel multi-core processors and coprocessors. We present the speed-up factor of generated Nussinov RNA parallel code and demonstrate that it is considerably faster than related codes in which only the two outer loops of the Nussinov loop nest are tiled.
Bio-Inspired Controller on an FPGA Applied to Closed-Loop Diaphragmatic Stimulation
Zbrzeski, Adeline; Bornat, Yannick; Hillen, Brian; Siu, Ricardo; Abbas, James; Jung, Ranu; Renaud, Sylvie
2016-01-01
Cervical spinal cord injury can disrupt connections between the brain respiratory network and the respiratory muscles which can lead to partial or complete loss of ventilatory control and require ventilatory assistance. Unlike current open-loop technology, a closed-loop diaphragmatic pacing system could overcome the drawbacks of manual titration as well as respond to changing ventilation requirements. We present an original bio-inspired assistive technology for real-time ventilation assistance, implemented in a digital configurable Field Programmable Gate Array (FPGA). The bio-inspired controller, which is a spiking neural network (SNN) inspired by the medullary respiratory network, is as robust as a classic controller while having a flexible, low-power and low-cost hardware design. The system was simulated in MATLAB with FPGA-specific constraints and tested with a computational model of rat breathing; the model reproduced experimentally collected respiratory data in eupneic animals. The open-loop version of the bio-inspired controller was implemented on the FPGA. Electrical test bench characterizations confirmed the system functionality. Open and closed-loop paradigm simulations were simulated to test the FPGA system real-time behavior using the rat computational model. The closed-loop system monitors breathing and changes in respiratory demands to drive diaphragmatic stimulation. The simulated results inform future acute animal experiments and constitute the first step toward the development of a neuromorphic, adaptive, compact, low-power, implantable device. The bio-inspired hardware design optimizes the FPGA resource and time costs while harnessing the computational power of spike-based neuromorphic hardware. Its real-time feature makes it suitable for in vivo applications. PMID:27378844
Alloys compatibility in molten salt fluorides: Kurchatov Institute related experience
NASA Astrophysics Data System (ADS)
Ignatiev, Victor; Surenkov, Alexandr
2013-10-01
In the last several years, there has been an increased interest in the use of high-temperature molten salt fluorides in nuclear power systems. For all molten salt reactor designs, materials selection is a very important issue. This paper summarizes results, which led to selection of materials for molten salt reactors in Russia. Operating experience with corrosion thermal convection loops has demonstrated good capability of the “nickel-molybdenum alloys + fluoride salt fueled by UF4 and PuF3 + cover gas” system up to 750 °C. A brief description is given of the container material work in progress. Tellurium corrosion of Ni-based alloys in stressed and unloaded conditions studies was also tested in different molten salt mixtures at temperatures up to 700-750 °C, also with measurement of the redox potential. HN80MTY alloy with 1% added Al is the most resistant to tellurium intergranular cracking of Ni-base alloys under study.
Regulative Loops, Step Loops and Task Loops
ERIC Educational Resources Information Center
VanLehn, Kurt
2016-01-01
This commentary suggests a generalization of the conception of the behavior of tutoring systems, which the target article characterized as having an outer loop that was executed once per task and an inner loop that was executed once per step of the task. A more general conception sees these two loops as instances of regulative loops, which…
Optimum design of hybrid phase locked loops
NASA Technical Reports Server (NTRS)
Lee, P.; Yan, T.
1981-01-01
The design procedure of phase locked loops is described in which the analog loop filter is replaced by a digital computer. Specific design curves are given for the step and ramp input changes in phase. It is shown that the designed digital filter depends explicitly on the product of the sampling time and the noise bandwidth of the phase locked loop. This technique of optimization can be applied to the design of digital analog loops for other applications.
Benchmark Simulation of Natural Circulation Cooling System with Salt Working Fluid Using SAM
DOE Office of Scientific and Technical Information (OSTI.GOV)
Ahmed, K. K.; Scarlat, R. O.; Hu, R.
Liquid salt-cooled reactors, such as the Fluoride Salt-Cooled High-Temperature Reactor (FHR), offer passive decay heat removal through natural circulation using Direct Reactor Auxiliary Cooling System (DRACS) loops. The behavior of such systems should be well-understood through performance analysis. The advanced system thermal-hydraulics tool System Analysis Module (SAM) from Argonne National Laboratory has been selected for this purpose. The work presented here is part of a larger study in which SAM modeling capabilities are being enhanced for the system analyses of FHR or Molten Salt Reactors (MSR). Liquid salt thermophysical properties have been implemented in SAM, as well as properties ofmore » Dowtherm A, which is used as a simulant fluid for scaled experiments, for future code validation studies. Additional physics modules to represent phenomena specific to salt-cooled reactors, such as freezing of coolant, are being implemented in SAM. This study presents a useful first benchmark for the applicability of SAM to liquid salt-cooled reactors: it provides steady-state and transient comparisons for a salt reactor system. A RELAP5-3D model of the Mark-1 Pebble-Bed FHR (Mk1 PB-FHR), and in particular its DRACS loop for emergency heat removal, provides steady state and transient results for flow rates and temperatures in the system that are used here for code-to-code comparison with SAM. The transient studied is a loss of forced circulation with SCRAM event. To the knowledge of the authors, this is the first application of SAM to FHR or any other molten salt reactors. While building these models in SAM, any gaps in the code’s capability to simulate such systems are identified and addressed immediately, or listed as future improvements to the code.« less
NASA Astrophysics Data System (ADS)
Prygarin, Alexander; Spradlin, Marcus; Vergu, Cristian; Volovich, Anastasia
2012-04-01
Recent progress on scattering amplitudes has benefited from the mathematical technology of symbols for efficiently handling the types of polylogarithm functions which frequently appear in multiloop computations. The symbol for all two-loop maximally helicity violating amplitudes in planar supersymmetric Yang-Mills theory is known, but explicit analytic formulas for the amplitudes are hard to come by except in special limits where things simplify, such as multi-Regge kinematics. By applying symbology we obtain a formula for the leading behavior of the imaginary part (the Mandelstam cut contribution) of this amplitude in multi-Regge kinematics for any number of gluons. Our result predicts a simple recursive structure which agrees with a direct Balitsky-Fadin-Kuraev-Lipatov computation carried out in a parallel publication.
NASA Astrophysics Data System (ADS)
Eun, H. C.; Cho, Y. Z.; Son, S. M.; Lee, T. K.; Yang, H. C.; Kim, I. T.; Lee, H. S.
2012-01-01
Recycling of LiCl-KCl eutectic salt wastes containing radioactive rare earth oxychlorides or oxides was studied to recover renewable salts from the salt wastes and to minimize the radioactive wastes by using a vacuum distillation method. Vaporization of the LiCl-KCl eutectic salt was effective above 900 °C and at 5 Torr. The condensations of the vaporized salt were largely dependent on temperature gradient. Based on these results, a recycling system of the salt wastes as a closed loop type was developed to obtain a high efficiency of the salt recovery condition. In this system, it was confirmed that renewable salt was recovered at more than 99 wt.% from the salt wastes, and the changes in temperature and pressure in the system could be utilized to understand the present condition of the system operation.
Where Does Road Salt Go - a Static Salt Model
NASA Astrophysics Data System (ADS)
Yu, C. W.; Liu, F.; Moriarty, V. W.
2017-12-01
Each winter, more than 15 million tons of road salt is applied in the United States for the de-icing purpose. Considerable amount of chloride in road salt flows into streams/drainage systems with the snow melt runoff and spring storms, and eventually goes into ecologically sensitive low-lying areas in the watershed, such as ponds and lakes. In many watersheds in the northern part of US, the chloride level in the water body has increased significantly in the past decades, and continues an upward trend. The environmental and ecological impact of the elevated chloride level can no longer be ignored. However although there are many studies on the biological impact of elevated chloride levels, there are few investigations on how the spatially distributed road salt application affects various parts of the watershed. In this presentation, we propose a static road salt model as a first-order metric to address spacial distribution of salt loading. Derived from the Topological Wetness Index (TWI) in many hydrological models, this static salt model provides a spatial impact as- sessment of road salt applications. To demonstrate the effectiveness of the static model, National Elevation Dataset (NED) of ten-meter resolution of Lake George watershed in New York State is used to generate the TWI, which is used to compute a spatially dis- tributed "salt-loading coefficient" of the whole watershed. Spatially varying salt applica- tion rate is then aggregated, using the salt-loading coefficients as weights, to provide salt loading assessments of streams in the watershed. Time-aggregated data from five CTD (conductivity-temperature-depth) sensors in selected streams are used for calibration. The model outputs and the sensor data demonstrate a strong linear correlation, with the R value of 0.97. The investigation shows that the static modeling approach may provide an effective method for the understanding the input and transport of road salt to within watersheds.
Qualls, A. Louis; Betzler, Benjamin R.; Brown, Nicholas R.; ...
2016-12-21
Engineering demonstration reactors are nuclear reactors built to establish proof of concept for technology options that have never been built. Examples of engineering demonstration reactors include Peach Bottom 1 for high temperature gas-cooled reactors (HTGRs) and Experimental Breeder Reactor-II (EBR-II) for sodium-cooled fast reactors. Historically, engineering demonstrations have played a vital role in advancing the technology readiness level of reactor technologies. Our paper details a preconceptual design for a fluoride salt-cooled engineering demonstration reactor. The fluoride salt-cooled high-temperature reactor (FHR) demonstration reactor (DR) is a concept for a salt-cooled reactor with 100 megawatts of thermal output (MWt). It would usemore » tristructural-isotropic (TRISO) particle fuel within prismatic graphite blocks. FLiBe (2 7LiF-BeF2) is the reference primary coolant. The FHR DR is designed to be small, simple, and affordable. Development of the FHR DR is a necessary intermediate step to enable near-term commercial FHRs. The design philosophy of the FHR DR was focused on safety, near-term deployment, and flexibility. Lower risk technologies are purposely included in the initial FHR DR design to ensure that the reactor can be built, licensed, and operated as an engineering demonstration with minimal risk and cost. These technologies include TRISO particle fuel, replaceable core structures, and consistent structural material selection for core structures and the primary and intermediate loops, and tube-and-shell primary-to-intermediate heat exchangers. Important capabilities to be demonstrated by building and operating the FHR DR include fabrication and operation of high temperature reactors; heat exchanger performance (including passive decay heat removal); pump performance; and reactivity control; salt chemistry control to maximize vessel life; tritium management; core design methodologies; salt procurement, handling, maintenance and ultimate
DOE Office of Scientific and Technical Information (OSTI.GOV)
Qualls, A. Louis; Betzler, Benjamin R.; Brown, Nicholas R.
Engineering demonstration reactors are nuclear reactors built to establish proof of concept for technology options that have never been built. Examples of engineering demonstration reactors include Peach Bottom 1 for high temperature gas-cooled reactors (HTGRs) and Experimental Breeder Reactor-II (EBR-II) for sodium-cooled fast reactors. Historically, engineering demonstrations have played a vital role in advancing the technology readiness level of reactor technologies. Our paper details a preconceptual design for a fluoride salt-cooled engineering demonstration reactor. The fluoride salt-cooled high-temperature reactor (FHR) demonstration reactor (DR) is a concept for a salt-cooled reactor with 100 megawatts of thermal output (MWt). It would usemore » tristructural-isotropic (TRISO) particle fuel within prismatic graphite blocks. FLiBe (2 7LiF-BeF2) is the reference primary coolant. The FHR DR is designed to be small, simple, and affordable. Development of the FHR DR is a necessary intermediate step to enable near-term commercial FHRs. The design philosophy of the FHR DR was focused on safety, near-term deployment, and flexibility. Lower risk technologies are purposely included in the initial FHR DR design to ensure that the reactor can be built, licensed, and operated as an engineering demonstration with minimal risk and cost. These technologies include TRISO particle fuel, replaceable core structures, and consistent structural material selection for core structures and the primary and intermediate loops, and tube-and-shell primary-to-intermediate heat exchangers. Important capabilities to be demonstrated by building and operating the FHR DR include fabrication and operation of high temperature reactors; heat exchanger performance (including passive decay heat removal); pump performance; and reactivity control; salt chemistry control to maximize vessel life; tritium management; core design methodologies; salt procurement, handling, maintenance and ultimate
Mini-review of knowledge gaps in salt tolerance of plants applied to willows and poplars
Jaconette Mirck; Ronald S. Zalesny
2015-01-01
Salt tolerance of agricultural crops has been studied since the 1940, but knowledge regarding salt tolerance of woody crops is still in its initial phase. Salt tolerance of agricultural crops has been expressed as the yield decrease due to a certain salt concentration within the root zone as compared to a non-saline control. The most well-known plant response curve to...
Balancing sub- and supra-salt strain in salt-influenced rifts: Implications for extension estimates
NASA Astrophysics Data System (ADS)
Coleman, Alexander J.; Jackson, Christopher A.-L.; Duffy, Oliver B.
2017-09-01
The structural style of salt-influenced rifts may differ from those formed in predominantly brittle crust. Salt can decouple sub- and supra-salt strain, causing sub-salt faults to be geometrically decoupled from, but kinematically coupled to and responsible for, supra-salt forced folding. Salt-influenced rifts thus contain more folds than their brittle counterparts, an observation often ignored in extension estimates. Fundamental to determining whether sub- and supra-salt structures are kinematically coherent, and the relative contributions of thin- (i.e. gravity-driven) and thick-skinned (i.e. whole-plate stretching) deformation to accommodating rift-related strain, is our ability to measure extension at both structural levels. We here use published physical models of salt-influenced extension to show that line-length estimates yield more accurate values of sub- and supra-salt extension compared to fault-heave, before applying these methods to seismic data from the Halten Terrace, offshore Norway. We show that, given the abundance of ductile deformation in salt-influenced rifts, significant amounts of extension may be ignored, leading to the erroneous interpretations of thin-skinned, gravity-gliding. If a system is kinematically coherent, supra-salt structures can help predict the occurrence and kinematics of sub-salt faults that may be poorly imaged and otherwise poorly constrained.
Phase-locked-loop interferometry applied to aspheric testing with a computer-stored compensator.
Servin, M; Malacara, D; Rodriguez-Vera, R
1994-05-01
A recently developed technique for continuous-phase determination of interferograms with a digital phase-locked loop (PLL) is applied to the null testing of aspheres. Although this PLL demodulating scheme is also a synchronous or direct interferometric technique, the separate unwrapping process is not explicitly required. The unwrapping and the phase-detection processes are achieved simultaneously within the PLL. The proposed method uses a computer-generated holographic compensator. The holographic compensator does not need to be printed out by any means; it is calculated and used from the computer. This computer-stored compensator is used as the reference signal to phase demodulate a sample interferogram obtained from the asphere being tested. Consequently the demodulated phase contains information about the wave-front departures from the ideal computer-stored aspheric interferogram. Wave-front differences of ~ 1 λ are handled easily by the proposed PLL scheme. The maximum recorded frequency in the template's interferogram as well as in the sampled interferogram are assumed to be below the Nyquist frequency.
Stability analysis and compensation of a boost regulator with two-loop control
NASA Technical Reports Server (NTRS)
Wester, G. W.
1974-01-01
A useful stability measure has been demonstrated by Wester (1973) for switching regulators with a single feedback loop by applying the Nyquist criterion to the approximate loop gain determined by a time-averaging technique. This approach is extended and applied to the characterization, stability analysis, and compensation design of a switching regulator with two-loop control. The role and relative significance of each control loop is clarified on the basis of a description of circuit operation, and the major and minor loops are identified. In view of the inapplicability of linear feedback theory, describing functions of the feedback loops and power stage are derived, using small-signal analysis. Several phenomena revealed from an analysis of the major loop gain are discussed.
NASA Technical Reports Server (NTRS)
Snell, Edward; vanderWoerd, Mark
2003-01-01
Thermally imaging the cryocooling processes of crystals has been demonstrated showing the progression of a cold wave through a crystal from the face closest to the origin of the coldstream ending at the point furthest away. During these studies large volume crystals were clearly distinguished from the loop holding them. Large volume crystals, used for neutron studies, were chosen deliberately to enhance the imaging. The different infrared transmission and reflectance properties of the crystal in comparison to the cryo-protectant are thought to be the parameter that produces the contrast making the crystal visible. As an application of the technology to locating crystals, more small crystals of lysozyme and a bFGF/dna complex were cryo-protected and imaged in large loops. The crystals were clearly distinguished from the vitrified solution. In the case of the bFGF/dna complex the illumination had to be carefully manipulated to enable the crystal to be seen in the visible spectrum. These preliminary results will be presented along with advantages and disadvantages of the technique and a discussion of how it might be applied.
Exploiting loop level parallelism in nonprocedural dataflow programs
NASA Technical Reports Server (NTRS)
Gokhale, Maya B.
1987-01-01
Discussed are how loop level parallelism is detected in a nonprocedural dataflow program, and how a procedural program with concurrent loops is scheduled. Also discussed is a program restructuring technique which may be applied to recursive equations so that concurrent loops may be generated for a seemingly iterative computation. A compiler which generates C code for the language described below has been implemented. The scheduling component of the compiler and the restructuring transformation are described.
Mathematical Modeling of Loop Heat Pipes
NASA Technical Reports Server (NTRS)
Kaya, Tarik; Ku, Jentung; Hoang, Triem T.; Cheung, Mark L.
1998-01-01
The primary focus of this study is to model steady-state performance of a Loop Heat Pipe (LHP). The mathematical model is based on the steady-state energy balance equations at each component of the LHP. The heat exchange between each LHP component and the surrounding is taken into account. Both convection and radiation environments are modeled. The loop operating temperature is calculated as a function of the applied power at a given loop condition. Experimental validation of the model is attempted by using two different LHP designs. The mathematical model is tested at different sink temperatures and at different elevations of the loop. Tbc comparison of the calculations and experimental results showed very good agreement (within 3%). This method proved to be a useful tool in studying steady-state LHP performance characteristics.
Structure of human thymidylate synthase under low-salt conditions.
Lovelace, Leslie L; Minor, Wladek; Lebioda, Lukasz
2005-05-01
Human thymidylate synthase, a target in cancer chemotherapy, was crystallized from PEG 3350 with 30 mM ammonium sulfate (AS) in the crystallization medium. The crystals are isomorphous with the high-salt crystals ( approximately 2.0 M AS) and the structure has been solved and refined (R = 22.6%, R(free) = 24.3%) at 1.8 A resolution. The high- and low-AS-concentration structures are quite similar, with loop 181-197 is in the inactive conformation. Also, residues 95-106 and 129-135 (eukaryotic inserts region) show high mobility as assessed by poor electron density and high values of crystallographic temperature factors (residues 1-25 and 108-129 are disordered in both structures). The high mobility of this region may reflect the situation at physiological ionic strength. Of the four sulfate ions observed bound at 2.0 M AS, only two are present at 30 mM AS. The inactive conformation appears to be stabilized by the side chain of Val3 or a leucine residue from the disordered regions. The low-salt conditions of these crystals should be much more suitable for the study of thymidylate synthase inhibitors, especially those that utilize sulfate-binding sites to stabilize the inactive conformation of loop 181-197.
Inverse spin Hall effect in a closed loop circuit
DOE Office of Scientific and Technical Information (OSTI.GOV)
Omori, Y.; Auvray, F.; Wakamura, T.
We present measurements of inverse spin Hall effects (ISHEs), in which the conversion of a spin current into a charge current via the ISHE is detected not as a voltage in a standard open circuit but directly as the charge current generated in a closed loop. The method is applied to the ISHEs of Bi-doped Cu and Pt. The derived expression of ISHE for the loop structure can relate the charge current flowing into the loop to the spin Hall angle of the SHE material and the resistance of the loop.
Helping crops stand up to salt
DOE Office of Scientific and Technical Information (OSTI.GOV)
Raeburn, P.
1985-05-01
A new approach to the problem of increasing soil salinity is to raise salt-tolerant plants. The search for such plants involves finding new applications for naturally occurring salt-resistant plants (halophytes), using conventional breeding techniques to identify and strengthen crop varieties known to have better-than-average salt tolerance, and applying recombinant DNA methods to introduce salt resistance into existing plants. One promising plant is salicornia, which produces oil high in polyunsaturates at a greater yield than soybeans. Two varieties of atriplex yield as much animal feed as alfalfa and can be harvested several times a year. Seed companies are supporting the research.
Decay-less kink oscillations in coronal loops
NASA Astrophysics Data System (ADS)
Anfinogentov, S.; Nisticò, G.; Nakariakov, V. M.
2013-12-01
Context. Kink oscillations of coronal loops in an off-limb active region are detected with the Imaging Assembly Array (AIA) instruments of the Solar Dynamics Observatory (SDO) at 171 Å. Aims: We aim to measure periods and amplitudes of kink oscillations of different loops and to determinate the evolution of the oscillation phase along the oscillating loop. Methods: Oscillating coronal loops were visually identified in the field of view of SDO/AIA and STEREO/EUVI-A: the loop length was derived by three-dimensional analysis. Several slits were taken along the loops to assemble time-distance maps. We identified oscillatory patterns and retrieved periods and amplitudes of the oscillations. We applied the cross-correlation technique to estimate the phase shift between oscillations at different segments of oscillating loops. Results: We found that all analysed loops show low-amplitude undamped transverse oscillations. Oscillation periods of loops in the same active region range from 2.5 to 11 min, and are different for different loops. The displacement amplitude is lower than 1 Mm. The oscillation phase is constant along each analysed loop. The spatial structure of the phase of the oscillations corresponds to the fundamental standing kink mode. We conclude that the observed behaviour is consistent with the empirical model in terms of a damped harmonic resonator affected by a non-resonant continuously operating external force. A movie is available in electronic form at http://www.aanda.org
Fontana, Roselei Claudete; da Silveira, Maurício Moura
2012-11-01
The production of endo- and exo-polygalacturonase (PG) by Aspergillus oryzae was assessed in stirred tank reactors (STRs), internal-loop airlift reactors (ILARs) and external-loop airlift reactors (ELARs). For STR production, we compared culture media formulated with either pectin (WBE) or partially hydrolyzed pectin. The highest enzyme activities were obtained in medium that contained 50% pectin in hydrolyzed form (WBE5). PG production in the three reactor types was compared for WBE5 and low salt WBE medium, with additional salts added at 48, 60 and 72h (WBES). The ELARs performed better than the ILARs in WBES medium where the exo-PG was the same concentration as for STRs and the endo-PG was 20% lower. These results indicate that PG production is higher under experimental conditions that result in higher cell growth with minimum pH values less than 3.0. Copyright © 2012 Elsevier Ltd. All rights reserved.
NASA Astrophysics Data System (ADS)
Broome, S. T.
2012-12-01
Design, analysis and performance assessment of potential salt repositories for heat-generating nuclear waste require knowledge of thermal, mechanical, and fluid transport properties of reconsolidating granular salt. Mechanical properties, Bulk (K) and Elastic (E) Moduli and Poisson's ratio (ν) are functions of porosity which decreases as the surrounding salt creeps inward and compresses granular salt within the rooms, drifts or shafts. To inform salt repository evaluations, we have undertaken an experimental program to determine K, E, and ν of reconsolidated granular salt as a function of porosity and temperature and to establish the deformational processes by which the salt reconsolidates. The experiments will be used to populate the database used in the reconsolidation model developed by Callahan (1999) which accounts for the effects of moisture through pressure solution and dislocation creep, with both terms dependent on effective stress to account for the effects of porosity. Mine-run salt from the Waste Isolation Pilot Program (WIPP) was first dried at 105 °C for a few days. Undeformed right-circular cylindrical sample assemblies of unconsolidated granular salt with an initial porosity of ~ 40%, nominally 10 cm in diameter and 17.5 cm in length, are jacketed in lead. Samples are placed in a pressure vessel and kept at test temperatures of 100, 175 or 250 °C; samples are vented to the atmosphere during the entire test procedure. At these test conditions the consolidating salt is always creeping, the creep rate increases with increasing temperature and stress and decreases as porosity decreases. In hydrostatic tests, confining pressure is increased to 20 MPa with periodic unload/reload loops to determine K. Volume strain increases with increasing temperature. In shear tests at 2.5 and 5 MPa confining pressure, after confining pressure is applied, the crushed salt is subjected to a differential stress, with periodic unload/reload loops to determine E and
Lionberger, Megan A.; Schoellhamer, David H.; Shellenbarger, Gregory; Orlando, James L.; Ganju, Neil K.
2007-01-01
This report documents the development and application of a box model to simulate water level, salinity, and temperature of the Alviso Salt Pond Complex in South San Francisco Bay. These ponds were purchased for restoration in 2003 and currently are managed by the U.S. Fish and Wildlife Service to maintain existing wildlife habitat and prevent a build up of salt during the development of a long-term restoration plan. The model was developed for the purpose of aiding pond managers during the current interim management period to achieve these goals. A previously developed box model of a salt pond, SPOOM, which calculates daily pond volume and salinity, was reconfigured to simulate multiple connected ponds and a temperature subroutine was added. The updated model simulates rainfall, evaporation, water flowing between the ponds and the adjacent tidal slough network, and water flowing from one pond to the next by gravity and pumps. Theoretical and measured relations between discharge and corresponding differences in water level are used to simulate most flows between ponds and between ponds and sloughs. The principle of conservation of mass is used to calculate daily pond volume and salinity. The model configuration includes management actions specified in the Interim Stewardship Plan for the ponds. The temperature subroutine calculates hourly net heat transfer to or from a pond resulting in a rise or drop in pond temperature and daily average, minimum, and maximum pond temperatures are recorded. Simulated temperature was compared with hourly measured data from pond 3 of the Napa?Sonoma Salt Pond Complex and monthly measured data from pond A14 of the Alviso Salt-Pond Complex. Comparison showed good agreement of measured and simulated pond temperature on the daily and monthly time scales.
Core Design Characteristics of the Fluoride Salt-Cooled High Temperature Demonstration Reactor
DOE Office of Scientific and Technical Information (OSTI.GOV)
Brown, Nicholas R; Qualls, A L; Betzler, Benjamin R
2016-01-01
Fluoride salt-cooled high temperature reactors (FHRs) are a promising reactor technology option with significant knowledge gaps to implementation. One potential approach to address those technology gaps is via a small-scale demonstration reactor with the goal of increasing the technology readiness level (TRL) of the overall system for the longer term. The objective of this paper is to outline a notional concept for such a system, and to address how the proposed concept would advance the TRL of FHR concepts. Development of the proposed FHR Demonstration Reactor (DR) will enable commercial FHR deployment through disruptive and rapid technology development and demonstration.more » The FHR DR will close remaining gaps to commercial viability. Lower risk technologies are included in the initial FHR DR design to ensure that the reactor can be built, licensed, and operated within an acceptable budget and schedule. Important capabilities that will be demonstrated by building and operating the FHR DR include core design methodologies; fabrication and operation of high temperature reactors; salt procurement, handling, maintenance, and ultimate disposal; salt chemistry control to maximize vessel life; tritium management; heat exchanger performance; pump performance; and reactivity control. The FHR DR is considered part of a broader set of FHR technology development and demonstration efforts, some of which are already underway. Nonreactor test efforts (e.g., heated salt loops or loops using simulant fluids) can demonstrate many technologies necessary for commercial deployment of FHRs. The FHR DR, however, fulfills a crucial role in FHR technology development by advancing the technical maturity and readiness level of the system as a whole.« less
The pH-dependent tertiary structure of a designed helix-loop-helix dimer.
Dolphin, G T; Baltzer, L
1997-01-01
De novo designed helix-loop-helix motifs can fold into well-defined tertiary structures if residues or groups of residues are incorporated at the helix-helix boundary to form helix-recognition sites that restrict the conformational degrees of freedom of the helical segments. Understanding the relationship between structure and function of conformational constraints therefore forms the basis for the engineering of non-natural proteins. This paper describes the design of an interhelical HisH+-Asp- hydrogen-bonded ion pair and the conformational stability of the folded helix-loop-helix motif. GTD-C, a polypeptide with 43 amino acid residues, has been designed to fold into a hairpin helix-loop-helix motif that can dimerise to form a four-helix bundle. The folded motif is in slow conformational exchange on the NMR timescale and has a well-dispersed 1H NMR spectrum, a narrow temperature interval for thermal denaturation and a near-UV CD spectrum with some fine structure. The conformational stability is pH dependent with an optimum that corresponds to the pH for maximum formation of a hydrogen-bonded ion pair between HisH17+ in helix I and Asp27- in helix II. The formation of an interhelical salt bridge is strongly suggested by the pH dependence of a number of spectroscopic probes to generate a well-defined tertiary structure in a designed helix-loop-helix motif. The thermodynamic stability of the folded motif is not increased by the formation of the salt bridge, but neighbouring conformations are destabilised. The use of this novel design principle in combination with hydrophobic interactions that provide sufficient binding energy in the folded structure should be of general use in de novo design of native-like proteins.
NASA Astrophysics Data System (ADS)
Závada, Prokop; Desbois, Guillaume; Urai, Janos; Schulmann, Karel; Rahmati, Mahmoud; Lexa, Ondrej; Wollenberg, Uwe
2014-05-01
Significant viscosity contrasts displayed in flow structures of a mountain namakier (Kuh-e-Namak - Dashti), between 'weak' terrestrial debris bearing rock salt types and 'strong' pure rock salt types are questioned for deformation mechanisms using detailed quantitative microstructural study including crystallographic preferred orientation (CPO) mapping of halite grains. While the solid impurity rich ("dirty") rock salts contain disaggregated siltstone and dolomite interlayers, "clean" salts (debris free) reveal microscopic hematite and remnants of abundant fluid inclusions in non-recrystallized cores of porphyroclasts. Although flow in both, the recrystallized dirty and clean salt types is accommodated by combined mechanisms of pressure-solution creep (PS), grain boundary sliding (GBS) and dislocation creep accommodated grain boundary migration (GBM), their viscosity contrasts are explained by significantly slower rates of intergranular diffusion and piling up of dislocations at hematite inclusions in clean salt types. Porphyroclasts of clean salts deform by semi-brittle and plastic mechanisms with intra-crystalline damage being induced also by fluid inclusions that explode in the crystals at high fluid pressures. Boudins of clean salt types with coarse grained and original sedimentary microstructure suggest that clean rock salts are associated with dislocation creep dominated power law flow in the source layer and the diapiric stem. Rheological contrasts between both rock salt classes apply in general for the variegated and terrestrial debris rich ("dirty") Lower Hormuz and the "clean" rock salt forming the Upper Hormuz, respectively, and suggest that large strain rate gradients likely exist along horizons of mobilized salt types of different composition and microstructure.
Seismic anisotropy in deforming salt bodies
NASA Astrophysics Data System (ADS)
Prasse, P.; Wookey, J. M.; Kendall, J. M.; Dutko, M.
2017-12-01
Salt is often involved in forming hydrocarbon traps. Studying salt dynamics and the deformation processes is important for the exploration industry. We have performed numerical texture simulations of single halite crystals deformed by simple shear and axial extension using the visco-plastic self consistent approach (VPSC). A methodology from subduction studies to estimate strain in a geodynamic simulation is applied to a complex high-resolution salt diapir model. The salt diapir deformation is modelled with the ELFEN software by our industrial partner Rockfield, which is based on a finite-element code. High strain areas at the bottom of the head-like strctures of the salt diapir show high amount of seismic anisotropy due to LPO development of halite crystals. The results demonstrate that a significant degree of seismic anisotropy can be generated, validating the view that this should be accounted for in the treatment of seismic data in, for example, salt diapir settings.
Paës, Gabriel; Cortés, Juan; Siméon, Thierry; O'Donohue, Michael J.; Tran, Vinh
2012-01-01
Dynamics is a key feature of enzyme catalysis. Unfortunately, current experimental and computational techniques do not yet provide a comprehensive understanding and description of functional macromolecular motions. In this work, we have extended a novel computational technique, which combines molecular modeling methods and robotics algorithms, to investigate functional motions of protein loops. This new approach has been applied to study the functional importance of the so-called thumb-loop in the glycoside hydrolase family 11 xylanase from Thermobacillus xylanilyticus (Tx-xyl). The results obtained provide new insight into the role of the loop in the glycosylation/deglycosylation catalytic cycle, and underline the key importance of the nature of the residue located at the tip of the thumb-loop. The effect of mutations predicted in silico has been validated by in vitro site-directed mutagenesis experiments. Overall, we propose a comprehensive model of Tx-xyl catalysis in terms of substrate and product dynamics by identifying the action of the thumb-loop motion during catalysis. PMID:24688637
On-the-fly reduction of open loops
NASA Astrophysics Data System (ADS)
Buccioni, Federico; Pozzorini, Stefano; Zoller, Max
2018-01-01
Building on the open-loop algorithm we introduce a new method for the automated construction of one-loop amplitudes and their reduction to scalar integrals. The key idea is that the factorisation of one-loop integrands in a product of loop segments makes it possible to perform various operations on-the-fly while constructing the integrand. Reducing the integrand on-the-fly, after each segment multiplication, the construction of loop diagrams and their reduction are unified in a single numerical recursion. In this way we entirely avoid objects with high tensor rank, thereby reducing the complexity of the calculations in a drastic way. Thanks to the on-the-fly approach, which is applied also to helicity summation and for the merging of different diagrams, the speed of the original open-loop algorithm can be further augmented in a very significant way. Moreover, addressing spurious singularities of the employed reduction identities by means of simple expansions in rank-two Gram determinants, we achieve a remarkably high level of numerical stability. These features of the new algorithm, which will be made publicly available in a forthcoming release of the OpenLoops program, are particularly attractive for NLO multi-leg and NNLO real-virtual calculations.
Reconsolidated Salt as a Geotechnical Barrier
DOE Office of Scientific and Technical Information (OSTI.GOV)
Hansen, Francis D.; Gadbury, Casey
Salt as a geologic medium has several attributes favorable to long-term isolation of waste placed in mined openings. Salt formations are largely impermeable and induced fractures heal as stress returns to equilibrium. Permanent isolation also depends upon the ability to construct geotechnical barriers that achieve nearly the same high-performance characteristics attributed to the native salt formation. Salt repository seal concepts often include elements of reconstituted granular salt. As a specific case in point, the Waste Isolation Pilot Plant recently received regulatory approval to change the disposal panel closure design from an engineered barrier constructed of a salt-based concrete to onemore » that employs simple run-of-mine salt and temporary bulkheads for isolation from ventilation. The Waste Isolation Pilot Plant is a radioactive waste disposal repository for defense-related transuranic elements mined from the Permian evaporite salt beds in southeast New Mexico. Its approved shaft seal design incorporates barrier components comprising salt-based concrete, bentonite, and substantial depths of crushed salt compacted to enhance reconsolidation. This paper will focus on crushed salt behavior when applied as drift closures to isolate disposal rooms during operations. Scientific aspects of salt reconsolidation have been studied extensively. The technical basis for geotechnical barrier performance has been strengthened by recent experimental findings and analogue comparisons. The panel closure change was accompanied by recognition that granular salt will return to a physical state similar to the halite surrounding it. Use of run-of-mine salt ensures physical and chemical compatibility with the repository environment and simplifies ongoing disposal operations. Our current knowledge and expected outcome of research can be assimilated with lessons learned to put forward designs and operational concepts for the next generation of salt repositories. Mined salt
In-Silico Identification Of Micro-Loops In Myelodysplastic Syndromes
NASA Astrophysics Data System (ADS)
Beck, Dominik; Brandl, Miriam; Pham, Tuan D.; Chang, Chung-Che; Zhou, Xiaobo
2011-06-01
Micro-loops are regulatory network motifs that leverage transcriptional and posttranscriptional control to effectively regulate the transcriptome. In this paper a regulatory network for Myelodysplastic Syndromes (MDSs) was constructed from the literature and publicly available data sources. The network was filtered using data from deep-sequencing of small RNAs, exon and microarrays. Motif discovery showed that micro-loops might exist in MDS. We further used the identified micro-loops and performed basic network analysis to identify the known disease gene RUNX1/AML, as well as miRNA family hsa-mir-181. This suggested that the concept of micro-loops can be applied to enhance disease gene identification and biomarker discovery.
Renal sodium transport in renin-deficient Dahl salt-sensitive rats
Pavlov, Tengis S; Levchenko, Vladislav; Ilatovskaya, Daria V; Moreno, Carol; Staruschenko, Alexander
2016-01-01
Objective: The Dahl salt-sensitive rat is a well-established model of salt-sensitive hypertension. The goal of this study was to assess the expression and activity of renal sodium channels and transporters in the renin-deficient salt-sensitive rat. Methods: Renin knockout (Ren−/−) rats created on the salt-sensitive rat background were used to investigate the role of renin in the regulation of ion transport in salt-sensitive hypertension. Western blotting and patch-clamp analyses were utilized to assess the expression level and activity of Na+ transporters. Results: It has been described previously that Ren−/− rats exhibit severe kidney underdevelopment, polyuria, and lower body weight and blood pressure compared to their wild-type littermates. Here we found that renin deficiency led to decreased expression of sodium-hydrogen antiporter (NHE3), the Na+/H+ exchanger involved in Na+ absorption in the proximal tubules, but did not affect the expression of Na-K-Cl cotransporter (NKCC2), the main transporter in the loop of Henle. In the distal nephron, the expression of sodium chloride cotransporter (NCC) was lower in Ren−/− rats. Single-channel patch clamp analysis detected decreased ENaC activity in Ren−/− rats which was mediated via changes in the channel open probability. Conclusion: These data illustrate that renin deficiency leads to significant dysregulation of ion transporters. PMID:27443990
Research on phase locked loop in optical memory servo system
NASA Astrophysics Data System (ADS)
Qin, Liqin; Ma, Jianshe; Zhang, Jianyong; Pan, Longfa; Deng, Ming
2005-09-01
Phase locked loop (PLL) is a closed loop automatic control system, which can track the phase of input signal. It widely applies in each area of electronic technology. This paper research the phase locked loop in optical memory servo area. This paper introduces the configuration of digital phase locked loop (PLL) and phase locked servo system, the control theory, and analyses system's stability. It constructs the phase locked loop experiment system of optical disk spindle servo, which based on special chip. DC motor is main object, this system adopted phase locked servo technique and digital signal processor (DSP) to achieve constant linear velocity (CLV) in controlling optical spindle motor. This paper analyses the factors that affect the stability of phase locked loop in spindle servo system, and discusses the affection to the optical disk readout signal and jitter due to the stability of phase locked loop.
The impact of high-salt exposure on cardiovascular development in the early chick embryo.
Wang, Guang; Zhang, Nuan; Wei, Yi-Fan; Jin, Yi-Mei; Zhang, Shi-Yao; Cheng, Xin; Ma, Zheng-Lai; Zhao, Shu-Zhu; Chen, You-Peng; Chuai, Manli; Hocher, Berthold; Yang, Xuesong
2015-11-01
In this study, we show that high-salt exposure dramatically increases chick mortality during embryo development. As embryonic mortality at early stages mainly results from defects in cardiovascular development, we focused on heart formation and angiogenesis. We found that high-salt exposure enhanced the risk of abnormal heart tube looping and blood congestion in the heart chamber. In the presence of high salt, both ventricular cell proliferation and apoptosis increased. The high osmolarity induced by high salt in the ventricular cardiomyocytes resulted in incomplete differentiation, which might be due to reduced expression of Nkx2.5 and GATA4. Blood vessel density and diameter were suppressed by exposure to high salt in both the yolk sac membrane (YSM) and chorioallantoic membrane models. In addition, high-salt-induced suppression of angiogenesis occurred even at the vasculogenesis stage, as blood island formation was also inhibited by high-salt exposure. At the same time, cell proliferation was repressed and cell apoptosis was enhanced by high-salt exposure in YSM tissue. Moreover, the reduction in expression of HIF2 and FGF2 genes might cause high-salt-suppressed angiogenesis. Interestingly, we show that high-salt exposure causes excess generation of reactive oxygen species (ROS) in the heart and YSM tissues, which could be partially rescued through the addition of antioxidants. In total, our study suggests that excess generation of ROS might play an important role in high-salt-induced defects in heart and angiogenesis. © 2015. Published by The Company of Biologists Ltd.
Nonpoint Source Road Salt Pollution from Urban Stormwater
NASA Astrophysics Data System (ADS)
DeGaetano, S.; Walter, M. T.
2014-12-01
In colder climates, such as the Northeast, road salts are commonly applied to deice roads in order to increase pedestrian and driver safety. This study was conducted to establish the mass if NaCl entering the local aquatic systems from Cornell's campus. Using trail cameras, two typical storm water pipes (draining into Cascadilla Creek) were monitored to determine the volume of runoff on an hourly bases. Grab samples were taken three times a week obtain storm water chloride concentration. In general, the average measured salt concentration was found to be 3.61 g/L, while high precipitation events Cl- concentration spiked to levels exceeding 12 g/L (≈ 20 g/L of salt). Combining runoff volumes and salt concentration values, a mass per drainage area was calculated for each monitored pipe. Outfall #1, located just upstream from the Wilson Synchrotron Module, expelled 262,300 kg of salt over a 42-day period of data collection while Outfall#2 discharged 4160 kg during the same period. These results were averaged and then applied to the total impervious area on Cornell's campus to approximate the total mass of sodium chloride leaving campus during the period of data collection.
Franson, J.C.; Friend, M.
1999-01-01
Animals become victims of salt poisoning or toxicosis when toxic levels of sodium and chloride accumulate in the blood after they ingest large amounts of salt or, in some species, are deprived of water. For birds, salt sources may include saline water and road salt.Normally, the salt glands of birds (Fig. 47.1) excrete sodium and chloride to maintain the proper physiologic chemical balance. However, when there has been insufficient time for acclimation of the salt gland to the saline environment, or when salt gland function is compromised by exposure to certain pesticides or oil, the electrolyte balance of the blood may be upset by the excess sodium and chloride, resulting in toxicosis. Salt accumulation on the outside of the body, or salt encrustation, is a greater problem for waterbirds that use very saline waters than is salt toxicosis. Salt encrustation can lead to exertion, acute muscle degeneration, and eventual drowning during the struggle to escape entrapment.
ERIC Educational Resources Information Center
Jefimenko, Oleg
1974-01-01
Discusses the design of a modified loop-the-loop apparatus in which a water stream is used to illustrate centripetal forces and phenomena of high-velocity hydrodynamics. Included are some procedures of carrying out lecture demonstrations. (CC)
NASA Astrophysics Data System (ADS)
Nishikawa, H.; Oshio, H.; Higa, M.; Kondo, R.; Kagoshima, S.; Nakao, A.; Sawa, H.; Yasuzuka, S.; Murata, K.
2008-10-01
Physical properties of isostructural β''-(DODHT)2X [DODHT = (l,4-dioxane-2,3-diyldithio)dihydrotetrathiafulvalene; X = PF6, AsF6, and SbF6] at ambient pressure have been compared. The insulating phase of β''-(DODHT)2PF6 salt has already been revealed to be a charge ordering (CO) state by X-ray diffraction study and magnetic behavior. CO in this salt was also confirmed by the observation of satellite reflections in oscillation photograph using synchrotron radiation. Transport property of β''-(DODHT)2SbF6 salt was reinvestigated up to the pressure of 3.7 GPa applied by a cubic anvil apparatus. Although the SbF6 salt turned to be metallic above 2.0 GPa, no superconductivity was observed. In order to examine the anion size dependence of DODHT salts with octahedral anions, we prepared a new DODHT salt, β''-(DODHT)2TaF6, which has the larger counter anion compared with the previous salts. Crystal structure of this salt was isostructural to the other DODHT salts. The electrical and magnetic properties of this salt were similar to those of β''-(DODHT)2SbF6 salt.
DOE Office of Scientific and Technical Information (OSTI.GOV)
O'Brien, James E.; Sabharwall, Piyush; Yoon, Su -Jong
2014-09-01
This report presents a conceptual design for a new high-temperature multi fluid, multi loop test facility for the INL to support thermal hydraulic, materials, and thermal energy storage research for nuclear and nuclear-hybrid applications. In its initial configuration, the facility will include a high-temperature helium loop, a liquid salt loop, and a hot water/steam loop. The three loops will be thermally coupled through an intermediate heat exchanger (IHX) and a secondary heat exchanger (SHX). Research topics to be addressed with this facility include the characterization and performance evaluation of candidate compact heat exchangers such as printed circuit heat exchangers (PCHEs)more » at prototypical operating conditions, flow and heat transfer issues related to core thermal hydraulics in advanced helium-cooled and salt-cooled reactors, and evaluation of corrosion behavior of new cladding materials and accident-tolerant fuels for LWRs at prototypical conditions. Based on its relevance to advanced reactor systems, the new facility has been named the Advanced Reactor Technology Integral System Test (ARTIST) facility. Research performed in this facility will advance the state of the art and technology readiness level of high temperature intermediate heat exchangers (IHXs) for nuclear applications while establishing the INL as a center of excellence for the development and certification of this technology. The thermal energy storage capability will support research and demonstration activities related to process heat delivery for a variety of hybrid energy systems and grid stabilization strategies. Experimental results obtained from this research will assist in development of reliable predictive models for thermal hydraulic design and safety codes over the range of expected advanced reactor operating conditions. Proposed/existing IHX heat transfer and friction correlations and criteria will be assessed with information on materials compatibility and
Wittkopp, Felix; Peeck, Lars; Hafner, Mathias; Frech, Christian
2018-04-13
Process development and characterization based on mathematic modeling provides several advantages and has been applied more frequently over the last few years. In this work, a Donnan equilibrium ion exchange (DIX) model is applied for modelling and simulation of ion exchange chromatography of a monoclonal antibody in linear chromatography. Four different cation exchange resin prototypes consisting of weak, strong and mixed ligands are characterized using pH and salt gradient elution experiments applying the extended DIX model. The modelling results are compared with the results using a classic stoichiometric displacement model. The Donnan equilibrium model is able to describe all four prototype resins while the stoichiometric displacement model fails for the weak and mixed weak/strong ligands. Finally, in silico chromatogram simulations of pH and pH/salt dual gradients are performed to verify the results and to show the consistency of the developed model. Copyright © 2018 Elsevier B.V. All rights reserved.
One-loop quantum gravity repulsion in the early Universe.
Broda, Bogusław
2011-03-11
Perturbative quantum gravity formalism is applied to compute the lowest order corrections to the classical spatially flat cosmological Friedmann-Lemaître-Robertson-Walker solution (for the radiation). The presented approach is analogous to the approach applied to compute quantum corrections to the Coulomb potential in electrodynamics, or rather to the approach applied to compute quantum corrections to the Schwarzschild solution in gravity. In the framework of the standard perturbative quantum gravity, it is shown that the corrections to the classical deceleration, coming from the one-loop graviton vacuum polarization (self-energy), have (UV cutoff free) opposite to the classical repulsive properties which are not negligible in the very early Universe. The repulsive "quantum forces" resemble those known from loop quantum cosmology.
NASA Astrophysics Data System (ADS)
Waxman, E.; Carlton, A. M. G.; Ziemann, P. J.; Volkamer, R. M.
2014-12-01
Secondary organic aerosol (SOA) formation from small water-soluble molecules such as glyoxal and methyl glyoxal is a topic of emerging interest. Results from recent field campaigns, e.g. Waxman et al. (2013, GRL) and Knote et al. (2014, ACP), show that these molecules can form significant SOA mass as a result of 'salting-in'. Salting-in happens when a molecule's solubility increases with salt concentration and salting-out is the reverse. Salting effects modify the solubility exponentially with increasing salt concentration, and thus the effective Henry's law constant can strongly modify partitioning, and multiphase chemical reaction rates in aerosol water. Moreover, the solubility in aerosol water cannot easily inferred based on the solubility in cloud water, as the salting effects could change the solubility by a factor of 104 or more. In this work, we have devised and applied a novel experimental setup to measure salting constants using an ion trap mass spectrometer. We focus on small, water soluble molecules like methyl glyoxal and similar compounds and measure salting constants for aerosol-relevant salts including ammonium sulfate, ammonium nitrate, and sodium chloride. The Setschenow salting-constant values are then used to parameterize the effects of salting in CMAQ. We present a series of sensitivity studies of the effects that inorganic aerosols have on the SOA formation from small soluble molecules in the southeastern United States.
Salt Acclimation of Cyanobacteria and Their Application in Biotechnology
Pade, Nadin; Hagemann, Martin
2014-01-01
The long evolutionary history and photo-autotrophic lifestyle of cyanobacteria has allowed them to colonize almost all photic habitats on Earth, including environments with high or fluctuating salinity. Their basal salt acclimation strategy includes two principal reactions, the active export of ions and the accumulation of compatible solutes. Cyanobacterial salt acclimation has been characterized in much detail using selected model cyanobacteria, but their salt sensing and regulatory mechanisms are less well understood. Here, we briefly review recent advances in the identification of salt acclimation processes and the essential genes/proteins involved in acclimation to high salt. This knowledge is of increasing importance because the necessary mass cultivation of cyanobacteria for future use in biotechnology will be performed in sea water. In addition, cyanobacterial salt resistance genes also can be applied to improve the salt tolerance of salt sensitive organisms, such as crop plants. PMID:25551682
DOE Office of Scientific and Technical Information (OSTI.GOV)
Novikov, V.M.
1995-10-01
The results of investigations on molten salt (MS) applications to problems of nuclear energy systems that have been conducted in Russian Research {open_quotes}Kurchatov Institute{close_quotes} are presented and discussed. The spectrum of these investigations is rather broad and covers the following items: physical characteristics of molten salt nuclear energy systems (MSNES); nuclear and radiation safety of MSNES; construction materials compatible with MS of different compositions; technological aspects of MS loops; in-reactor loop testing. It is shown that main findings of completed program support the conclusion that there are no physical nor technological obstacles on way of MS application to different nuclearmore » energy systems.« less
Seeburger, Joerg; Noack, Thilo; Winkfein, Michael; Ender, Joerg; Mohr, Friedrich Wilhelm
2010-01-01
The loop technique facilitates mitral valve repair for leaflet prolapse by implantation of Gore-Tex neo-chordae. The key feature of the technique is a premade bundle of four loops made out of one suture. The loops are available in different lengths ranging from 10 to 26 mm. After assessment of the ideal length of neo-chordae with a caliper the loops are then secured to the body of the papillary muscle over an additional felt pledget. In the following step, the free ends of the loops are distributed along the free margin of the prolapsing segment using one additional suture for each loop.
First Results from a Hardware-in-the-Loop Demonstration of Closed-Loop Autonomous Formation Flying
NASA Technical Reports Server (NTRS)
Gill, E.; Naasz, Bo; Ebinuma, T.
2003-01-01
A closed-loop system for the demonstration of autonomous satellite formation flying technologies using hardware-in-the-loop has been developed. Making use of a GPS signal simulator with a dual radio frequency outlet, the system includes two GPS space receivers as well as a powerful onboard navigation processor dedicated to the GPS-based guidance, navigation, and control of a satellite formation in real-time. The closed-loop system allows realistic simulations of autonomous formation flying scenarios, enabling research in the fields of tracking and orbit control strategies for a wide range of applications. The autonomous closed-loop formation acquisition and keeping strategy is based on Lyapunov's direct control method as applied to the standard set of Keplerian elements. This approach not only assures global and asymptotic stability of the control but also maintains valuable physical insight into the applied control vectors. Furthermore, the approach can account for system uncertainties and effectively avoids a computationally expensive solution of the two point boundary problem, which renders the concept particularly attractive for implementation in onboard processors. A guidance law has been developed which strictly separates the relative from the absolute motion, thus avoiding the numerical integration of a target trajectory in the onboard processor. Moreover, upon using precise kinematic relative GPS solutions, a dynamical modeling or filtering is avoided which provides for an efficient implementation of the process on an onboard processor. A sample formation flying scenario has been created aiming at the autonomous transition of a Low Earth Orbit satellite formation from an initial along-track separation of 800 m to a target distance of 100 m. Assuming a low-thrust actuator which may be accommodated on a small satellite, a typical control accuracy of less than 5 m has been achieved which proves the applicability of autonomous formation flying techniques to
Comparison between two models of energy balance in coronal loops
NASA Astrophysics Data System (ADS)
Mac Cormack, C.; López Fuentes, M.; Vásquez, A. M.; Nuevo, F. A.; Frazin, R. A.; Landi, E.
2017-10-01
In this work we compare two models to analyze the energy balance along coronal magnetic loops. For the first stationary model we deduce an expression of the energy balance along the loops expressed in terms of quantities provided by the combination of differential emission measure tomography (DEMT) applied to EUV images time series and potential extrapolations of the coronal magnetic field. The second applied model is a 0D hydrodynamic model that provides the evolution of the average properties of the coronal plasma along the loops, using as input parameters the loop length and the heating rate obtained with the first model. We compare the models for two Carrington rotations (CR) corresponding to different periods of activity: CR 2081, corresponding to a period of minimum activity observed with the Extreme Ultraviolet Imager (EUVI) on board of the Solar Terrestrial Relations Observatory (STEREO), and CR 2099, corresponding to a period of activity increase observed with the Atmospheric Imaging Assembly (AIA) on board the Solar Dynamics Observatory (SDO). The results of the models are consistent for both rotations.
An integrand reconstruction method for three-loop amplitudes
NASA Astrophysics Data System (ADS)
Badger, Simon; Frellesvig, Hjalte; Zhang, Yang
2012-08-01
We consider the maximal cut of a three-loop four point function with massless kinematics. By applying Gröbner bases and primary decomposition we develop a method which extracts all ten propagator master integral coefficients for an arbitrary triple-box configuration via generalized unitarity cuts. As an example we present analytic results for the three loop triple-box contribution to gluon-gluon scattering in Yang-Mills with adjoint fermions and scalars in terms of three master integrals.
Micromechanical processes in consolidated granular salt
Mills, Melissa Marie; Stormont, John C.; Bauer, Stephen J.
2018-03-27
Here, granular salt is likely to be used as backfill material and a seal system component within geologic salt formations serving as a repository for long-term isolation of nuclear waste. Pressure from closure of the surrounding salt formation will promote consolidation of granular salt, eventually resulting in properties comparable to native salt. Understanding dependence of consolidation processes on stress state, moisture availability, temperature, and time is important for demonstrating sealing functions and long-term repository performance. This study characterizes laboratory-consolidated granular salt by means of microstructural observations. Granular salt material from mining operations was obtained from the bedded Salado Formation hostingmore » the Waste Isolation Pilot Plant and the Avery Island salt dome. Laboratory test conditions included hydrostatic consolidation of jacketed granular salt with varying conditions of confining isochoric stress to 38 MPa, temperature to 250 °C, moisture additions of 1% by weight, time duration, and vented and non-vented states. Resultant porosities ranged between 1% and 22%. Optical and scanning electron microscopic techniques were used to ascertain consolidation mechanisms. From these investigations, samples with 1% added moisture or unvented during consolidation, exhibit clear pressure solution processes with tightly cohered grain boundaries and occluded fluid pores. Samples with only natural moisture content consolidated by a combination of brittle, cataclastic, and crystal plastic deformation. Recrystallization at 250 °C irrespective of moisture conditions was also observed. The range and variability of conditions applied in this study, combined with the techniques used to display microstructural features, are unique, and provide insight into an important area of governing deformation mechanism(s) occurring within salt repository applications.« less
Micromechanical processes in consolidated granular salt
DOE Office of Scientific and Technical Information (OSTI.GOV)
Mills, Melissa Marie; Stormont, John C.; Bauer, Stephen J.
Here, granular salt is likely to be used as backfill material and a seal system component within geologic salt formations serving as a repository for long-term isolation of nuclear waste. Pressure from closure of the surrounding salt formation will promote consolidation of granular salt, eventually resulting in properties comparable to native salt. Understanding dependence of consolidation processes on stress state, moisture availability, temperature, and time is important for demonstrating sealing functions and long-term repository performance. This study characterizes laboratory-consolidated granular salt by means of microstructural observations. Granular salt material from mining operations was obtained from the bedded Salado Formation hostingmore » the Waste Isolation Pilot Plant and the Avery Island salt dome. Laboratory test conditions included hydrostatic consolidation of jacketed granular salt with varying conditions of confining isochoric stress to 38 MPa, temperature to 250 °C, moisture additions of 1% by weight, time duration, and vented and non-vented states. Resultant porosities ranged between 1% and 22%. Optical and scanning electron microscopic techniques were used to ascertain consolidation mechanisms. From these investigations, samples with 1% added moisture or unvented during consolidation, exhibit clear pressure solution processes with tightly cohered grain boundaries and occluded fluid pores. Samples with only natural moisture content consolidated by a combination of brittle, cataclastic, and crystal plastic deformation. Recrystallization at 250 °C irrespective of moisture conditions was also observed. The range and variability of conditions applied in this study, combined with the techniques used to display microstructural features, are unique, and provide insight into an important area of governing deformation mechanism(s) occurring within salt repository applications.« less
From Loops to Trees By-passing Feynman's Theorem
DOE Office of Scientific and Technical Information (OSTI.GOV)
Catani, Stefano; Gleisberg, Tanju; Krauss, Frank
2008-04-22
We derive a duality relation between one-loop integrals and phase-space integrals emerging from them through single cuts. The duality relation is realized by a modification of the customary + i0 prescription of the Feynman propagators. The new prescription regularizing the propagators, which we write in a Lorentz covariant form, compensates for the absence of multiple cut contributions that appear in the Feynman Tree Theorem. The duality relation can be applied to generic one-loop quantities in any relativistic, local and unitary field theories. It is suitable for applications to the analytical calculation of one-loop scattering amplitudes, and to the numerical evaluationmore » of cross-sections at next-to-leading order.« less
Optical injection phase-lock loops
NASA Astrophysics Data System (ADS)
Bordonalli, Aldario Chrestani
Locking techniques have been widely applied for frequency synchronisation of semiconductor lasers used in coherent communication and microwave signal generation systems. Two main locking techniques, the optical phase-lock loop (OPLL) and optical injection locking (OIL) are analysed in this thesis. The principal limitations on OPLL performance result from the loop propagation delay, which makes difficult the implementation of high gain and wide bandwidth loops, leading to poor phase noise suppression performance and requiring the linewidths of the semiconductor laser sources to be less than a few megahertz for practical values of loop delay. The OIL phase noise suppression is controlled by the injected power. The principal limitations of the OIL implementation are the finite phase error under locked conditions and the narrow stable locking range the system provides at injected power levels required to reduce the phase noise output of semiconductor lasers significantly. This thesis demonstrates theoretically and experimentally that it is possible to overcome the limitations of OPLL and OIL systems by combining them, to form an optical injection phase-lock loop (OIPLL). The modelling of an OIPLL system is presented and compared with the equivalent OPLL and OIL results. Optical and electrical design of an homodyne OIPLL is detailed. Experimental results are given which verify the theoretical prediction that the OIPLL would keep the phase noise suppression as high as that of the OIL system over a much wider stable locking range, even with wide linewidth lasers and long loop delays. The experimental results for lasers with summed linewidth of 36 MHz and a loop delay of 15 ns showed measured phase error variances as low as 0.006 rad2 (500 MHz bandwidth) for locking bandwidths greater than 26 GHz, compared with the equivalent OPLL phase error variance of around 1 rad2 (500 MHz bandwidth) and the equivalent OIL locking bandwidth of less than 1.2 GHz.
Shortening a loop can increase protein native state entropy.
Gavrilov, Yulian; Dagan, Shlomi; Levy, Yaakov
2015-12-01
Protein loops are essential structural elements that influence not only function but also protein stability and folding rates. It was recently reported that shortening a loop in the AcP protein may increase its native state conformational entropy. This effect on the entropy of the folded state can be much larger than the lower entropic penalty of ordering a shorter loop upon folding, and can therefore result in a more pronounced stabilization than predicted by polymer model for loop closure entropy. In this study, which aims at generalizing the effect of loop length shortening on native state dynamics, we use all-atom molecular dynamics simulations to study how gradual shortening a very long or solvent-exposed loop region in four different proteins can affect their stability. For two proteins, AcP and Ubc7, we show an increase in native state entropy in addition to the known effect of the loop length on the unfolded state entropy. However, for two permutants of SH3 domain, shortening a loop results only with the expected change in the entropy of the unfolded state, which nicely reproduces the observed experimental stabilization. Here, we show that an increase in the native state entropy following loop shortening is not unique to the AcP protein, yet nor is it a general rule that applies to all proteins following the truncation of any loop. This modification of the loop length on the folded state and on the unfolded state may result with a greater effect on protein stability. © 2015 Wiley Periodicals, Inc.
Electrostatic correlations in inhomogeneous charged fluids beyond loop expansion
NASA Astrophysics Data System (ADS)
Buyukdagli, Sahin; Achim, C. V.; Ala-Nissila, T.
2012-09-01
Electrostatic correlation effects in inhomogeneous symmetric electrolytes are investigated within a previously developed electrostatic self-consistent theory [R. R. Netz and H. Orland, Eur. Phys. J. E 11, 301 (2003)], 10.1140/epje/i2002-10159-0. To this aim, we introduce two computational approaches that allow to solve the self-consistent equations beyond the loop expansion. The first method is based on a perturbative Green's function technique, and the second one is an extension of a previously introduced semiclassical approximation for single dielectric interfaces to the case of slit nanopores. Both approaches can handle the case of dielectrically discontinuous boundaries where the one-loop theory is known to fail. By comparing the theoretical results obtained from these schemes with the results of the Monte Carlo simulations that we ran for ions at neutral single dielectric interfaces, we first show that the weak coupling Debye-Huckel theory remains quantitatively accurate up to the bulk ion density ρb ≃ 0.01 M, whereas the self-consistent theory exhibits a good quantitative accuracy up to ρb ≃ 0.2 M, thus improving the accuracy of the Debye-Huckel theory by one order of magnitude in ionic strength. Furthermore, we compare the predictions of the self-consistent theory with previous Monte Carlo simulation data for charged dielectric interfaces and show that the proposed approaches can also accurately handle the correlation effects induced by the surface charge in a parameter regime where the mean-field result significantly deviates from the Monte Carlo data. Then, we derive from the perturbative self-consistent scheme the one-loop theory of asymmetrically partitioned salt systems around a dielectrically homogeneous charged surface. It is shown that correlation effects originate in these systems from a competition between the salt screening loss at the interface driving the ions to the bulk region, and the interfacial counterion screening excess attracting
Electrostatic correlations in inhomogeneous charged fluids beyond loop expansion.
Buyukdagli, Sahin; Achim, C V; Ala-Nissila, T
2012-09-14
Electrostatic correlation effects in inhomogeneous symmetric electrolytes are investigated within a previously developed electrostatic self-consistent theory [R. R. Netz and H. Orland, Eur. Phys. J. E 11, 301 (2003)]. To this aim, we introduce two computational approaches that allow to solve the self-consistent equations beyond the loop expansion. The first method is based on a perturbative Green's function technique, and the second one is an extension of a previously introduced semiclassical approximation for single dielectric interfaces to the case of slit nanopores. Both approaches can handle the case of dielectrically discontinuous boundaries where the one-loop theory is known to fail. By comparing the theoretical results obtained from these schemes with the results of the Monte Carlo simulations that we ran for ions at neutral single dielectric interfaces, we first show that the weak coupling Debye-Huckel theory remains quantitatively accurate up to the bulk ion density ρ(b) ≃ 0.01 M, whereas the self-consistent theory exhibits a good quantitative accuracy up to ρ(b) ≃ 0.2 M, thus improving the accuracy of the Debye-Huckel theory by one order of magnitude in ionic strength. Furthermore, we compare the predictions of the self-consistent theory with previous Monte Carlo simulation data for charged dielectric interfaces and show that the proposed approaches can also accurately handle the correlation effects induced by the surface charge in a parameter regime where the mean-field result significantly deviates from the Monte Carlo data. Then, we derive from the perturbative self-consistent scheme the one-loop theory of asymmetrically partitioned salt systems around a dielectrically homogeneous charged surface. It is shown that correlation effects originate in these systems from a competition between the salt screening loss at the interface driving the ions to the bulk region, and the interfacial counterion screening excess attracting them towards the surface
Ahmad, Aftab; Niwa, Yasuo; Goto, Shingo; Ogawa, Takeshi; Shimizu, Masanori; Suzuki, Akane; Kobayashi, Kyoko; Kobayashi, Hirokazu
2015-01-01
An activation-tagging methodology was applied to dedifferentiated calli of Arabidopsis to identify new genes involved in salt tolerance. This identified salt tolerant callus 8 (stc8) as a gene encoding the basic helix-loop-helix transcription factor bHLH106. bHLH106-knockout (KO) lines were more sensitive to NaCl, KCl, LiCl, ABA, and low temperatures than the wild-type. Back-transformation of the KO line rescued its phenotype, and over-expression (OX) of bHLH106 in differentiated plants exhibited tolerance to NaCl. Green fluorescent protein (GFP) fused with bHLH106 revealed that it was localized to the nucleus. Prepared bHLH106 protein was subjected to electrophoresis mobility shift assays against E-box sequences (5'-CANNTG-3'). The G-box sequence 5'-CACGTG-3' had the strongest interaction with bHLH106. bHLH106-OX lines were transcriptomically analyzed, and resultant up- and down-regulated genes selected on the criterion of presence of a G-box sequence. There were 198 genes positively regulated by bHLH106 and 36 genes negatively regulated; these genes possessed one or more G-box sequences in their promoter regions. Many of these genes are known to be involved in abiotic stress response. It is concluded that bHLH106 locates at a branching point in the abiotic stress response network by interacting directly to the G-box in genes conferring salt tolerance on plants.
Development of Murray Loop Bridge for High Induced Voltage
NASA Astrophysics Data System (ADS)
Isono, Shigeki; Kawasaki, Katsutoshi; Kobayashi, Shin-Ichi; Ishihara, Hayato; Chiyajo, Kiyonobu
In the case of the cable fault that ground fault resistance is less than 10MΩ, Murray Loop Bridge is excellent as a fault locator in location accuracy and the convenience. But, when the induction of several hundred V is taken from the single core cable which adjoins it, a fault location with the high voltage Murray Loop Bridge becomes difficult. Therefore, we developed Murray Loop Bridge, which could be applied even when the induced voltage of several hundred V occurs in the measurement cable. The evaluation of the fault location accuracy was done with the developed prototype by the actual line and the training equipment.
Renormalization of loop functions for all loops
DOE Office of Scientific and Technical Information (OSTI.GOV)
Brandt, R.A.; Neri, F.; Sato, M.
1981-08-15
It is shown that the vacuum expectation values W(C/sub 1/,xxx, C/sub n/) of products of the traces of the path-ordered phase factors P exp(igcontour-integral/sub C/iA/sub ..mu../(x)dx/sup ..mu../) are multiplicatively renormalizable in all orders of perturbation theory. Here A/sub ..mu../(x) are the vector gauge field matrices in the non-Abelian gauge theory with gauge group U(N) or SU(N), and C/sub i/ are loops (closed paths). When the loops are smooth (i.e., differentiable) and simple (i.e., non-self-intersecting), it has been shown that the generally divergent loop functions W become finite functions W when expressed in terms of the renormalized coupling constant and multipliedmore » by the factors e/sup -K/L(C/sub i/), where K is linearly divergent and L(C/sub i/) is the length of C/sub i/. It is proved here that the loop functions remain multiplicatively renormalizable even if the curves have any finite number of cusps (points of nondifferentiability) or cross points (points of self-intersection). If C/sub ..gamma../ is a loop which is smooth and simple except for a single cusp of angle ..gamma.., then W/sub R/(C/sub ..gamma../) = Z(..gamma..)W(C/sub ..gamma../) is finite for a suitable renormalization factor Z(..gamma..) which depends on ..gamma.. but on no other characteristic of C/sub ..gamma../. This statement is made precise by introducing a regularization, or via a loop-integrand subtraction scheme specified by a normalization condition W/sub R/(C-bar/sub ..gamma../) = 1 for an arbitrary but fixed loop C-bar/sub ..gamma../. Next, if C/sub ..beta../ is a loop which is smooth and simple except for a cross point of angles ..beta.., then W(C/sub ..beta../) must be renormalized together with the loop functions of associated sets S/sup i//sub ..beta../ = )C/sup i//sub 1/,xxx, C/sup i//sub p/i) (i = 2,xxx,I) of loops C/sup i//sub q/ which coincide with certain parts of C/sub ..beta../equivalentC/sup 1//sub 1/. Then W/sub R/(S/sup i//sub ..beta../) = Z/sup i
DOE Office of Scientific and Technical Information (OSTI.GOV)
James E. O'Brien; Piyush Sabharwall; SuJong Yoon
2001-11-01
Effective and robust high temperature heat transfer systems are fundamental to the successful deployment of advanced reactors for both power generation and non-electric applications. Plant designs often include an intermediate heat transfer loop (IHTL) with heat exchangers at either end to deliver thermal energy to the application while providing isolation of the primary reactor system. In order to address technical feasibility concerns and challenges a new high-temperature multi-fluid, multi-loop test facility “Advanced Reactor Technology Integral System Test facility” (ARTIST) is under development at the Idaho National Laboratory. The facility will include three flow loops: high-temperature helium, molten salt, and steam/water.more » Details of some of the design aspects and challenges of this facility, which is currently in the conceptual design phase, are discussed« less
A proof for loop-law constraints in stoichiometric metabolic networks
2012-01-01
Background Constraint-based modeling is increasingly employed for metabolic network analysis. Its underlying assumption is that natural metabolic phenotypes can be predicted by adding physicochemical constraints to remove unrealistic metabolic flux solutions. The loopless-COBRA approach provides an additional constraint that eliminates thermodynamically infeasible internal cycles (or loops) from the space of solutions. This allows the prediction of flux solutions that are more consistent with experimental data. However, it is not clear if this approach over-constrains the models by removing non-loop solutions as well. Results Here we apply Gordan’s theorem from linear algebra to prove for the first time that the constraints added in loopless-COBRA do not over-constrain the problem beyond the elimination of the loops themselves. Conclusions The loopless-COBRA constraints can be reliably applied. Furthermore, this proof may be adapted to evaluate the theoretical soundness for other methods in constraint-based modeling. PMID:23146116
Salt gland distribution in limonium bicolor at the individual level
NASA Astrophysics Data System (ADS)
Leng, B. Y.; Yuan, F.; Dong, X. X.; Wang, B. S.
2018-02-01
Limonium bicolor is a typical exo-recretohalophyte with multi-cellular salt glands. A differential interference contrast (DIC) microscope were applied to investigate the pattern of salt gland distribution in L. bicolor at the individual level. For a single mature leaf, more salt glands are distributed in the leaf central and apical regions than leaf base. For the leaves in different developmental stages, firstly, the density of salt glands linearly decreased at the beginning of leaf expansion and kept a relatively constant value in the later periods, which was mainly due to the rapid expansion of epidermal cells. Secondly, the total number of glands per leaf showed a reversed trend compared to the density of salt glands. These results suggested that the salt gland density was adapted to the leaf age and area as more and more salt accumulated in the saline soils.
Antimicrobial Polymeric Materials with Quaternary Ammonium and Phosphonium Salts
Xue, Yan; Xiao, Huining; Zhang, Yi
2015-01-01
Polymeric materials containing quaternary ammonium and/or phosphonium salts have been extensively studied and applied to a variety of antimicrobial-relevant areas. With various architectures, polymeric quaternary ammonium/phosphonium salts were prepared using different approaches, exhibiting different antimicrobial activities and potential applications. This review focuses on the state of the art of antimicrobial polymers with quaternary ammonium/phosphonium salts. In particular, it discusses the structure and synthesis method, mechanisms of antimicrobial action, and the comparison of antimicrobial performance between these two kinds of polymers. PMID:25667977
De Kock, H L; Zandstra, E H; Sayed, N; Wentzel-Viljoen, E
2016-01-01
This study investigated the impact of salt reduction on liking, salt taste perception, and use of table salt when consuming chicken stew in light of South Africa's new salt recommendations. In total, 432 South-African consumers (aged 35.2 ± 12.3 years) consumed a full portion of a chicken stew meal once at a central location. Four stock cube powders varying in salt content were used to prepare chicken stews: 1) no reduction - 2013 Na level; regular salt level as currently available on the South African market (24473 mg Na/100 g), 2) salt reduction smaller than 2016 level, i.e. 10%-reduced (22025 mg Na/100 g), 3) 2016 salt level, as per regulatory prescriptions (18000 mg Na/100 g), 4) 2019 salt level, as per regulatory prescriptions (13000 mg Na/100 g). Consumers were randomly allocated to consume one of the four meals. Liking, salt taste perception, and use of table salt and pepper were measured. Chicken stews prepared with reduced-salt stock powders were equally well-liked as chicken stews with the current salt level. Moreover, a gradual reduction of the salt in the chicken stews resulted in a reduced salt intake, up to an average of 19% for the total group compared to the benchmark 2013 Na level stew. However, 19% of consumers compensated by adding salt back to full compensation in some cases. More salt was added with increased reductions of salt in the meals, even to the point of full compensation. Further investigation into the impacts of nutrition communication and education about salt reduction on salt taste perception and use is needed. This research provides new consumer insights on salt use and emphasises the need for consumer-focused behaviour change approaches, in addition to reformulation of products. Copyright © 2015 Elsevier Ltd. All rights reserved.
Sea Salt vs. Table Salt: What's the Difference?
... Nutrition and healthy eating What's the difference between sea salt and table salt? Answers from Katherine Zeratsky, R.D., L.D. The main differences between sea salt and table salt are in their taste, ...
Two-loop hard-thermal-loop thermodynamics with quarks
NASA Astrophysics Data System (ADS)
Andersen, Jens O.; Petitgirard, Emmanuel; Strickland, Michael
2004-08-01
We calculate the quark contribution to the free energy of a hot quark-gluon plasma to two-loop order using hard-thermal-loop (HTL) perturbation theory. All ultraviolet divergences can be absorbed into renormalizations of the vacuum energy and the HTL quark and gluon mass parameters. The quark and gluon HTL mass parameters are determined self-consistently by a variational prescription. Combining the quark contribution with the two-loop HTL perturbation theory free energy for pure glue we obtain the total two-loop QCD free energy. Comparisons are made with lattice estimates of the free energy for Nf=2 and with exact numerical results obtained in the large-Nf limit.
View of salt crystals inserted within a 50mm metal loop in the U.S. Laboratory
2003-03-15
ISS006-E-39339 (15 March 2003) --- A close up view of sodium chloride crystals in a water bubble within a 50-millimeter metal loop was photographed by an Expedition Six crewmember. The experiment took place in the Destiny laboratory on the International Space Station (ISS).
Invasive Knotweeds are Highly Tolerant to Salt Stress
NASA Astrophysics Data System (ADS)
Rouifed, Soraya; Byczek, Coline; Laffray, Daniel; Piola, Florence
2012-12-01
Japanese knotweed s.l. are some of the most invasive plants in the world. Some genotypes are known to be tolerant to the saline concentrations found in salt marshes. Here we focus on tolerance to higher concentrations in order to assess whether the species are able to colonize and establish in highly stressful environments, or whether salt is an efficient management tool. In a first experiment, adult plants of Fallopia japonica, Fallopia × bohemica and Fallopia sachalinensis were grown under salt stress conditions by watering with saline concentrations of 6, 30, 120, or 300 g L-1 for three weeks to assess the response of the plants to a spill of salt. At the two highest concentrations, their leaves withered and fell. There were no effects on the aboveground parts at the lowest concentrations. Belowground dry weight and number of buds were reduced from 30 and 120 g L-1 of salt, respectively. In a second experiment, a single spraying of 120 g L-1 of salt was applied to individuals of F. × bohemica and their stems were clipped to assess the response to a potential control method. 60 % of the plants regenerated. Regeneration was delayed by the salt treatment and shoot growth slowed down. This study establishes the tolerance of three Fallopia taxa to strong salt stress, with no obvious differences between taxa. Their salt tolerance could be an advantage in their ability to colonize polluted environments and to survive to spills of salt.
Extended Impact of Pin1 Catalytic Loop Phosphorylation Revealed by S71E Phosphomimetic.
Mahoney, Brendan J; Zhang, Meiling; Zintsmaster, John S; Peng, Jeffrey W
2018-03-02
Pin1 is a two-domain human protein that catalyzes the cis-trans isomerization of phospho-Ser/Thr-Pro (pS/T-P) motifs in numerous cell-cycle regulatory proteins. These pS/T-P motifs bind to Pin1's peptidyl-prolyl isomerase (PPIase) domain in a catalytic pocket, between an extended catalytic loop and the PPIase domain core. Previous studies showed that post-translational phosphorylation of S71 in the catalytic loop decreases substrate binding affinity and isomerase activity. To define the origins for these effects, we investigated a phosphomimetic Pin1 mutant, S71E-Pin1, using solution NMR. We find that S71E perturbs not only its host loop but also the nearby PPIase core. The perturbations identify a local network of hydrogen bonds and salt bridges that is more extended than previously thought, and includes interactions between the catalytic loop and the α2/α3 turn in the PPIase core. Explicit-solvent molecular dynamics simulations and phylogenetic analysis suggest that these interactions act as conserved "latches" between the loop and PPIase core that enhance binding of phosphorylated substrates, as they are absent in PPIases lacking pS/T-P specificity. Our results suggest that S71 is a hub residue within an electrostatic network primed for phosphorylation, and may illustrate a common mechanism of phosphorylation-mediated allostery. Copyright © 2018 Elsevier Ltd. All rights reserved.
The modified Altemeier procedure for a loop colostomy prolapse.
Watanabe, Makoto; Murakami, Masahiko; Ozawa, Yoshiaki; Uchida, Marie; Yamazaki, Kimiyasu; Fujimori, Akira; Otsuka, Koji; Aoki, Takeshi
2015-11-01
Loop colostomy prolapse is associated with an impaired quality of life. Surgical treatment may sometimes be required for cases that cannot be closed by colon colostomy because of high-risk morbidities or advanced disease. We applied the Altimeter operation for patients with transverse loop colostomy. The Altemeier operation is therefore indicated for rectal prolapse. This technique involves a simple operation, which includes a circumferential incision through the full thickness of the outer and inner cylinder of the prolapsed limb, without incising the abdominal wall, and anastomosis with sutures using absorbable thread. We performed the Altemeier operation for three cases of loop stomal prolapse. Those patients demonstrated no postoperative complications (including obstruction, prolapse recurrence, or hernia). Our findings suggest that this procedure is useful as an optional surgical treatment for cases of transverse loop colostomy prolapse as a permanent measure in patients with high-risk morbidities or advanced disease.
Closed loop problems in biomechanics. Part II--an optimization approach.
Vaughan, C L; Hay, J G; Andrews, J G
1982-01-01
A closed loop problem in biomechanics may be defined as a problem in which there are one or more closed loops formed by the human body in contact with itself or with an external system. Under certain conditions the problem is indeterminate--the unknown forces and torques outnumber the equations. Force transducing devices, which would help solve this problem, have serious drawbacks, and existing methods are inaccurate and non-general. The purposes of the present paper are (1) to develop a general procedure for solving closed loop problems; (2) to illustrate the application of the procedure; and (3) to examine the validity of the procedure. A mathematical optimization approach is applied to the solution of three different closed loop problems--walking up stairs, vertical jumping and cartwheeling. The following conclusions are drawn: (1) the method described is reasonably successful for predicting horizontal and vertical reaction forces at the distal segments although problems exist for predicting the points of application of these forces; (2) the results provide some support for the notion that the human neuromuscular mechanism attempts to minimize the joint torques and thus, to a certain degree, the amount of muscular effort; (3) in the validation procedure it is desirable to have a force device for each of the distal segments in contact with a fixed external system; and (4) the method is sufficiently general to be applied to all classes of closed loop problems.
Behaviour of fractional loop delay zero crossing digital phase locked loop (FR-ZCDPLL)
NASA Astrophysics Data System (ADS)
Nasir, Qassim
2018-01-01
This article analyses the performance of the first-order zero crossing digital phase locked loops (FR-ZCDPLL) when fractional loop delay is added to loop. The non-linear dynamics of the loop is presented, analysed and examined through bifurcation behaviour. Numerical simulation of the loop is conducted to proof the mathematical analysis of the loop operation. The results of the loop simulation show that the proposed FR-ZCDPLL has enhanced the performance compared to the conventional zero crossing DPLL in terms of wider lock range, captured range and stable operation region. In addition, extensive experimental simulation was conducted to find the optimum loop parameters for different loop environmental conditions. The addition of the fractional loop delay network in the conventional loop also reduces the phase jitter and its variance especially when the signal-to-noise ratio is low.
Does TRACE Resolve Isothermal Coronal Loops?
NASA Astrophysics Data System (ADS)
Weber, Mark A.; Schmelz, J.; Kashyap, V.; Roames, J.
2006-06-01
Historically, increasing resolution of solar data has revealed ever smaller length scales for both the thermodynamics and the magnetic structure of the corona. Furthermore, the dynamics there are governed by magnetohydrodynamic processes which are difficult to observe or model. Recent results in the literature suggest that some coronal loops with cross-sections near the resolution limits of the Transition Region and Coronal Explorer (pixel size = 0.5 arc-seconds, or approx. 360 km) are, in fact, isothermally homogeneous and thus may be identified as elementary loop strands. This poster presents some ongoing work that applies state-of-the-art estimation of differential emission measures in order to evaluate these claims for a sample of loops. We find that the data give no evidence to prefer the "isothermal" hypothesis over the "multithermal" hypothesis. The authors are supported by the following funds: contract SP02H820IR to the Lockheed-Martin Corp.; NSF grant ATM-0402729; NASA grant NNG05GE68G; and NASA contracts NAS8-39073 and NAS8-03060.
Suggestopedia to SALT and a New Awareness in Education.
ERIC Educational Resources Information Center
Herr, Kay U.
SALT, suggestive-accelerative learning and teaching, is the Americanized version of a pedagogy developed in Bulgaria. While most extensively applied to foreign language teaching, the methodology may be applied to any discipline, particularly one based upon a foundation of learned facts. This document applies the method to ESL classes. The teacher…
An approach toward the numerical evaluation of multi-loop Feynman diagrams
NASA Astrophysics Data System (ADS)
Passarino, Giampiero
2001-12-01
A scheme for systematically achieving accurate numerical evaluation of multi-loop Feynman diagrams is developed. This shows the feasibility of a project aimed to produce a complete calculation for two-loop predictions in the Standard Model. As a first step an algorithm, proposed by F.V. Tkachov and based on the so-called generalized Bernstein functional relation, is applied to one-loop multi-leg diagrams with particular emphasis to the presence of infrared singularities, to the problem of tensorial reduction and to the classification of all singularities of a given diagram. Successively, the extension of the algorithm to two-loop diagrams is examined. The proposed solution consists in applying the functional relation to the one-loop sub-diagram which has the largest number of internal lines. In this way the integrand can be made smooth, a part from a factor which is a polynomial in xS, the vector of Feynman parameters needed for the complementary sub-diagram with the smallest number of internal lines. Since the procedure does not introduce new singularities one can distort the xS-integration hyper-contour into the complex hyper-plane, thus achieving numerical stability. The algorithm is then modified to deal with numerical evaluation around normal thresholds. Concise and practical formulas are assembled and presented, numerical results and comparisons with the available literature are shown and discussed for the so-called sunset topology.
Improved Design and Fabrication of Hydrated-Salt Pills
NASA Technical Reports Server (NTRS)
Shirron, Peter J.; DiPirro, Michael J.; Canavan, Edgar R.
2011-01-01
A high-performance design, and fabrication and growth processes to implement the design, have been devised for encapsulating a hydrated salt in a container that both protects the salt and provides thermal conductance between the salt and the environment surrounding the container. The unitary salt/container structure is known in the art as a salt pill. In the original application of the present design and processes, the salt is, more specifically, a hydrated paramagnetic salt, for use as a refrigerant in a very-low-temperature adiabatic demagnetization refrigerator (ADR). The design and process can also be applied, with modifications, to other hydrated salts. Hydrated paramagnetic salts have long been used in ADRs because they have the desired magnetic properties at low temperatures. They also have some properties, disadvantageous for ADRs, that dictate the kind of enclosures in which they must be housed: Being hydrated, they lose water if exposed to less than 100-percent relative humidity. Because any dehydration compromises their magnetic properties, salts used in ADRs must be sealed in hermetic containers. Because they have relatively poor thermal conductivities in the temperature range of interest (<0.1 K), integral thermal buses are needed as means of efficiently transferring heat to and from the salts during refrigeration cycles. A thermal bus is typically made from a high-thermal-conductivity met al (such as copper or gold), and the salt is configured to make intimate thermal contact with the metal. Commonly in current practice (and in the present design), the thermal bus includes a matrix of wires or rods, and the salt is grown onto this matrix. The density and spacing of the conductors depend on the heat fluxes that must be accommodated during operation.
Magnetic properties of four Cu(ii)-amino acid salts
NASA Astrophysics Data System (ADS)
Calvo, Rafael
1984-03-01
We report a comparative study of magnetic properties of the Cu(II) salts of the amino acids l-alanine, dl-α-amino-n-butyric acid, α-amino isobutyric acid, and l-isoleucine. The position of the EPR lines of these quasi-two-dimensional magnetic systems was measured as a function of temperature T between 293 and 1.5 K, at 9.3 GHz and for magnetic fields applied along three axes of single crystal samples. Large changes of the gyromagnetic factor with T have been observed. They are attributed to an internal mean field, proportional to the applied field, which appears when the temperature is lowered due to short range magnetic order in the paramagnetic phase of the salts. The problem of short range magnetic order and g shifts in Cu-amino acid salts is discussed and compared with previous observations in Mn one-dimensional systems.
NASA Astrophysics Data System (ADS)
Zhang, Shuangshuang; Qi, Shuanhu; Klushin, Leonid I.; Skvortsov, Alexander M.; Yan, Dadong; Schmid, Friederike
2018-01-01
We use Brownian dynamics simulations and analytical theory to compare two prominent types of single molecule transitions. One is the adsorption transition of a loop (a chain with two ends bound to an attractive substrate) driven by an attraction parameter ɛ and the other is the loop-stretch transition in a chain with one end attached to a repulsive substrate, driven by an external end-force F applied to the free end. Specifically, we compare the behavior of the respective order parameters of the transitions, i.e., the mean number of surface contacts in the case of the adsorption transition and the mean position of the chain end in the case of the loop-stretch transition. Close to the transition points, both the static behavior and the dynamic behavior of chains with different length N are very well described by a scaling ansatz with the scaling parameters (ɛ - ɛ*)Nϕ (adsorption transition) and (F - F*)Nν (loop-stretch transition), respectively, where ϕ is the crossover exponent of the adsorption transition and ν is the Flory exponent. We show that both the loop-stretch and the loop adsorption transitions provide an exceptional opportunity to construct explicit analytical expressions for the crossover functions which perfectly describe all simulation results on static properties in the finite-size scaling regime. Explicit crossover functions are based on the ansatz for the analytical form of the order parameter distributions at the respective transition points. In contrast to the close similarity in equilibrium static behavior, the dynamic relaxation at the two transitions shows qualitative differences, especially in the strongly ordered regimes. This is attributed to the fact that the surface contact dynamics in a strongly adsorbed chain is governed by local processes, whereas the end height relaxation of a strongly stretched chain involves the full spectrum of Rouse modes.
Loop optimization for tensor network renormalization
NASA Astrophysics Data System (ADS)
Yang, Shuo; Gu, Zheng-Cheng; Wen, Xiao-Gang
We introduce a tensor renormalization group scheme for coarse-graining a two-dimensional tensor network, which can be successfully applied to both classical and quantum systems on and off criticality. The key idea of our scheme is to deform a 2D tensor network into small loops and then optimize tensors on each loop. In this way we remove short-range entanglement at each iteration step, and significantly improve the accuracy and stability of the renormalization flow. We demonstrate our algorithm in the classical Ising model and a frustrated 2D quantum model. NSF Grant No. DMR-1005541 and NSFC 11274192, BMO Financial Group, John Templeton Foundation, Government of Canada through Industry Canada, Province of Ontario through the Ministry of Economic Development & Innovation.
Key issues in the computational simulation of GPCR function: representation of loop domains
NASA Astrophysics Data System (ADS)
Mehler, E. L.; Periole, X.; Hassan, S. A.; Weinstein, H.
2002-11-01
Some key concerns raised by molecular modeling and computational simulation of functional mechanisms for membrane proteins are discussed and illustrated for members of the family of G protein coupled receptors (GPCRs). Of particular importance are issues related to the modeling and computational treatment of loop regions. These are demonstrated here with results from different levels of computational simulations applied to the structures of rhodopsin and a model of the 5-HT2A serotonin receptor, 5-HT2AR. First, comparative Molecular Dynamics (MD) simulations are reported for rhodopsin in vacuum and embedded in an explicit representation of the membrane and water environment. It is shown that in spite of a partial accounting of solvent screening effects by neutralization of charged side chains, vacuum MD simulations can lead to severe distortions of the loop structures. The primary source of the distortion appears to be formation of artifactual H-bonds, as has been repeatedly observed in vacuum simulations. To address such shortcomings, a recently proposed approach that has been developed for calculating the structure of segments that connect elements of secondary structure with known coordinates, is applied to 5-HT2AR to obtain an initial representation of the loops connecting the transmembrane (TM) helices. The approach consists of a simulated annealing combined with biased scaled collective variables Monte Carlo technique, and is applied to loops connecting the TM segments on both the extra-cellular and the cytoplasmic sides of the receptor. Although this initial calculation treats the loops as independent structural entities, the final structure exhibits a number of interloop interactions that may have functional significance. Finally, it is shown here that in the case where a given loop from two different GPCRs (here rhodopsin and 5-HT2AR) has approximately the same length and some degree of sequence identity, the fold adopted by the loops can be similar. Thus
2016-09-15
A series of active regions stretched along the right side of the sun exhibited a wide variety of loops cascading above them (Sept. 12-14, 2016). The active region near the center has tightly coiled loops, while the region rotating over the right edge has some elongated and some very stretched loops above it. The loops are actually charged particles spiraling along magnetic field lines, observed here in a wavelength of extreme ultraviolet light. Near the middle of the video the Earth quickly passes in front of a portion of the sun as viewed by SDO. http://photojournal.jpl.nasa.gov/catalog/PIA16997
Landau singularities and symbology: One- and two-loop MHV amplitudes in SYM theory
Dennen, Tristan; Spradlin, Marcus; Volovich, Anastasia
2016-03-14
We apply the Landau equations, whose solutions parameterize the locus of possible branch points, to the one- and two-loop Feynman integrals relevant to MHV amplitudes in planar N = 4 super-Yang-Mills theory. We then identify which of the Landau singularities appear in the symbols of the amplitudes, and which do not. Finally, we observe that all of the symbol entries in the two-loop MHV amplitudes are already present as Landau singularities of one-loop pentagon integrals.
Yoo, Do Guen; Lee, Ho Min; Sadollah, Ali; Kim, Joong Hoon
2015-01-01
Water supply systems are mainly classified into branched and looped network systems. The main difference between these two systems is that, in a branched network system, the flow within each pipe is a known value, whereas in a looped network system, the flow in each pipe is considered an unknown value. Therefore, an analysis of a looped network system is a more complex task. This study aims to develop a technique for estimating the optimal pipe diameter for a looped agricultural irrigation water supply system using a harmony search algorithm, which is an optimization technique. This study mainly serves two purposes. The first is to develop an algorithm and a program for estimating a cost-effective pipe diameter for agricultural irrigation water supply systems using optimization techniques. The second is to validate the developed program by applying the proposed optimized cost-effective pipe diameter to an actual study region (Saemangeum project area, zone 6). The results suggest that the optimal design program, which applies an optimization theory and enhances user convenience, can be effectively applied for the real systems of a looped agricultural irrigation water supply.
Lee, Ho Min; Sadollah, Ali
2015-01-01
Water supply systems are mainly classified into branched and looped network systems. The main difference between these two systems is that, in a branched network system, the flow within each pipe is a known value, whereas in a looped network system, the flow in each pipe is considered an unknown value. Therefore, an analysis of a looped network system is a more complex task. This study aims to develop a technique for estimating the optimal pipe diameter for a looped agricultural irrigation water supply system using a harmony search algorithm, which is an optimization technique. This study mainly serves two purposes. The first is to develop an algorithm and a program for estimating a cost-effective pipe diameter for agricultural irrigation water supply systems using optimization techniques. The second is to validate the developed program by applying the proposed optimized cost-effective pipe diameter to an actual study region (Saemangeum project area, zone 6). The results suggest that the optimal design program, which applies an optimization theory and enhances user convenience, can be effectively applied for the real systems of a looped agricultural irrigation water supply. PMID:25874252
High-temperature molten salt thermal energy storage systems
NASA Technical Reports Server (NTRS)
Petri, R. J.; Claar, T. D.; Tison, R. R.; Marianowski, L. G.
1980-01-01
The results of comparative screening studies of candidate molten carbonate salts as phase change materials (PCM) for advanced solar thermal energy storage applications at 540 to 870 C (1004 to 1600 F) and steam Rankine electric generation at 400 to 540 C (752 to 1004 F) are presented. Alkali carbonates are attractive as latent heat storage materials because of their relatively high storage capacity and thermal conductivity, low corrosivity, moderate cost, and safe and simple handling requirements. Salts were tested in 0.1 kWhr lab scale modules and evaluated on the basis of discharge heat flux, solidification temperature range, thermal cycling stability, and compatibility with containment materials. The feasibility of using a distributed network of high conductivity material to increase the heat flux through the layer of solidified salt was evaluated. The thermal performance of an 8 kWhr thermal energy storage (TES) module containing LiKCO3 remained very stable throughout 5650 hours and 130 charge/discharge cycles at 480 to 535 C (896 to 995 F). A TES utilization concept of an electrical generation peaking subsystem composed of a multistage condensing steam turbine and a TES subsystem with a separate power conversion loop was defined. Conceptual designs for a 100 MW sub e TES peaking system providing steam at 316 C, 427 C, and 454 C (600 F, 800 F, and 850 F) at 3.79 million Pa (550 psia) were developed and evaluated. Areas requiring further investigation have also been identified.
Efficiently computing exact geodesic loops within finite steps.
Xin, Shi-Qing; He, Ying; Fu, Chi-Wing
2012-06-01
Closed geodesics, or geodesic loops, are crucial to the study of differential topology and differential geometry. Although the existence and properties of closed geodesics on smooth surfaces have been widely studied in mathematics community, relatively little progress has been made on how to compute them on polygonal surfaces. Most existing algorithms simply consider the mesh as a graph and so the resultant loops are restricted only on mesh edges, which are far from the actual geodesics. This paper is the first to prove the existence and uniqueness of geodesic loop restricted on a closed face sequence; it contributes also with an efficient algorithm to iteratively evolve an initial closed path on a given mesh into an exact geodesic loop within finite steps. Our proposed algorithm takes only an O(k) space complexity and an O(mk) time complexity (experimentally), where m is the number of vertices in the region bounded by the initial loop and the resultant geodesic loop, and k is the average number of edges in the edge sequences that the evolving loop passes through. In contrast to the existing geodesic curvature flow methods which compute an approximate geodesic loop within a predefined threshold, our method is exact and can apply directly to triangular meshes without needing to solve any differential equation with a numerical solver; it can run at interactive speed, e.g., in the order of milliseconds, for a mesh with around 50K vertices, and hence, significantly outperforms existing algorithms. Actually, our algorithm could run at interactive speed even for larger meshes. Besides the complexity of the input mesh, the geometric shape could also affect the number of evolving steps, i.e., the performance. We motivate our algorithm with an interactive shape segmentation example shown later in the paper.
NASA Astrophysics Data System (ADS)
Ardali, Ayça Sultan; Tezkan, Bülent; Gürer, Aysan
2018-02-01
Durusu Lake is the biggest and most important freshwater source supplying drinking water to the European side of Istanbul. In this study, electrical resistivity tomography (ERT) and transient electromagnetic (TEM) measurements were applied to detect a possible salt water intrusion into the lake and to delineate the subsurface structure in the north of Durusu Lake. The ERT and TEM measurements were carried out along six parallel profiles extending from the sea coast to the lake shore on the dune barrier. TEM data were interpreted using different 1-D inversion methods such as Occam, Marquardt, and laterally constrained inversion (LCI). ERT data were interpreted using 2-D inversion techniques. The inversion results of ERT and TEM data were shown as resistivity depth sections including topography. The sand layer spreading over the basin has a resistivity of 150-400 Ωm with a thickness of 5-10 m. The sandy layer with clay, silt, and gravel has a resistivity of 15-100 Ωm and a thickness of 10-40 m followed by a clay layer of a resistivity below 10 Ωm. When the inversion of these data is interpreted along with the hydrogeology of the area, it is concluded that the salt water intrusion along the dune barrier is not common and occurs at a particular area where the distance between lake and sea is very close. Using information from boreholes around the lake, it was verified that the common conductive region at depths of 30 m or more consists of clay layers and clay lenses.
NASA Astrophysics Data System (ADS)
Scarlat, Raluca Olga
approach to the PB-FHR annular pebble bed core cooled by fluoride salt mixtures generated a model that is called Pod. Pod. was used to show the resilience of the PB-FHR core to generation of hot spots or cold spots, due to the effect of buoyancy on the flow and temperature distribution in the packed bed. Pod. was used to investigate the PB-FHR response to ATWS transients. Based on the functional requirements for the core, Pod. was used to generate an optimized design of the flow distribution in the core. An analysis of natural circulation loops cooled by single-phase Boussinesq fluids is presented here, in the context of reactor design that relies on natural circulation decay heat removal, and design of scaled experiments. The scaling arguments are established for a transient natural circulation loop, for loops that have long fluid residence time, and negligible contribution of fluid inertia to the momentum equation. The design of integral effects tests for the loss of forced circulation (LOFC) for PB-FHR is discussed. The special case of natural circulation decay heat removal from a pebble bed reactor was analyzed. A way to define the Reynolds number in a multi-dimensional pebble bed was identified. The scaling methodology for replicating pebble bed friction losses using an electrically resistance heated annular pipe and a needle valve was developed. The thermophysical properties of liquid fluoride salts lead to design of systems with low flow velocities, and hence long fluid residence times. A comparison among liquid coolants for the performance of steady state natural circulation heat removal from a pebble bed was performed. Transient natural circulation experimental data with simulant fluids for fluoride salts is given here. The low flow velocity and the relatively high viscosity of the fluoride salts lead to low Reynolds number flows, and a low Reynolds number in conjunction with a sufficiently high coefficient of thermal expansion makes the system susceptible to
Permanent Disposal of Nuclear Waste in Salt
NASA Astrophysics Data System (ADS)
Hansen, F. D.
2016-12-01
Salt formations hold promise for eternal removal of nuclear waste from our biosphere. Germany and the United States have ample salt formations for this purpose, ranging from flat-bedded formations to geologically mature dome structures. Both nations are revisiting nuclear waste disposal options, accompanied by extensive collaboration on applied salt repository research, design, and operation. Salt formations provide isolation while geotechnical barriers reestablish impermeability after waste is placed in the geology. Between excavation and closure, physical, mechanical, thermal, chemical, and hydrological processes ensue. Salt response over a range of stress and temperature has been characterized for decades. Research practices employ refined test techniques and controls, which improve parameter assessment for features of the constitutive models. Extraordinary computational capabilities require exacting understanding of laboratory measurements and objective interpretation of modeling results. A repository for heat-generative nuclear waste provides an engineering challenge beyond common experience. Long-term evolution of the underground setting is precluded from direct observation or measurement. Therefore, analogues and modeling predictions are necessary to establish enduring safety functions. A strong case for granular salt reconsolidation and a focused research agenda support salt repository concepts that include safety-by-design. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000. Author: F. D. Hansen, Sandia National Laboratories
Graph Structured Program Evolution: Evolution of Loop Structures
NASA Astrophysics Data System (ADS)
Shirakawa, Shinichi; Nagao, Tomoharu
Recently, numerous automatic programming techniques have been developed and applied in various fields. A typical example is genetic programming (GP), and various extensions and representations of GP have been proposed thus far. Complex programs and hand-written programs, however, may contain several loops and handle multiple data types. In this chapter, we propose a new method called Graph Structured Program Evolution (GRAPE). The representation of GRAPE is a graph structure; therefore, it can represent branches and loops using this structure. Each programis constructed as an arbitrary directed graph of nodes and a data set. The GRAPE program handles multiple data types using the data set for each type, and the genotype of GRAPE takes the form of a linear string of integers. We apply GRAPE to three test problems, factorial, exponentiation, and list sorting, and demonstrate that the optimum solution in each problem is obtained by the GRAPE system.
21 CFR 100.155 - Salt and iodized salt.
Code of Federal Regulations, 2010 CFR
2010-04-01
... 21 Food and Drugs 2 2010-04-01 2010-04-01 false Salt and iodized salt. 100.155 Section 100.155 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN CONSUMPTION GENERAL Specific Administrative Rulings and Decisions § 100.155 Salt and iodized salt. (a) For the purposes of this section, the...
Loop electrostatics modulates the intersubunit interactions in ferritin.
Bernacchioni, Caterina; Ghini, Veronica; Pozzi, Cecilia; Di Pisa, Flavio; Theil, Elizabeth C; Turano, Paola
2014-11-21
Functional ferritins are 24-mer nanocages that self-assemble with extended contacts between pairs of 4-helix bundle subunits coupled in an antiparallel fashion along the C2 axes. The largest intersubunit interaction surface in the ferritin nanocage involves helices, but contacts also occur between groups of three residues midway in the long, solvent-exposed L-loops of facing subunits. The anchor points between intersubunit L-loop pairs are the salt bridges between the symmetry-related, conserved residues Asp80 and Lys82. The resulting quaternary structure of the cage is highly soluble and thermostable. Substitution of negatively charged Asp80 with a positively charged Lys in homopolymeric M ferritin introduces electrostatic repulsions that inhibit the oligomerization of the ferritin subunits. D80K ferritin was present in inclusion bodies under standard overexpressing conditions in E. coli, contrasting with the wild type protein. Small amounts of fully functional D80K nanocages formed when expression was slowed. The more positively charged surface results in a different solubility profile and D80K crystallized in a crystal form with a low density packing. The 3D structure of D80K variant is the same as wild type except for the side chain orientations of Lys80 and facing Lys82. When three contiguous Lys groups are introduced in D80KI81K ferritin variant the nanocage assembly is further inhibited leading to lower solubility and reduced thermal stability. Here, we demonstrate that the electrostatic pairing at the center of the L-loops has a specific kinetic role in the self-assembly of ferritin nanocages.
Diclofenac salts. III. Alkaline and earth alkaline salts.
Fini, Adamo; Fazio, Giuseppe; Rosetti, Francesca; Angeles Holgado, M; Iruín, Ana; Alvarez-Fuentes, Josefa
2005-11-01
Diclofenac salts containing the alkaline and two earth alkaline cations have been prepared and characterized by scanning electron microscopy (SEM) and EDAX spectroscopy; and by thermal and thermogravimetric analysis (TGA): all of them crystallize as hydrate when precipitated from water. The salts dehydrate at room temperature and more easily on heating, but recovery the hydration, when placed in a humid environment. X-ray diffraction spectra suggest that on dehydration new peaks appear on diffractograms and the lattice of the salts partially looses crystallinity. This phenomenon is readily visible in the case of the calcium and magnesium salts, whose thermograms display a crystallization exotherm, before melting or decomposing at temperatures near or above 200 degrees C; these last salts appear to form solvates, when prepared from methanol. The thermogram of each salt shows a complex endotherm of dehydration about 100 degrees C; the calcium salt displays two endotherms, well separated at about 120 and 160 degrees C, which disappear after prolonged heating. Decomposition exotherms, before or soon after the melting, appear below 300 degrees C. The ammonium salt is thermally unstable and, when heated to start dehydration, dissociates and leaves acidic diclofenac.
DOE Office of Scientific and Technical Information (OSTI.GOV)
Melin, Alexander M.; Kisner, Roger A.
2016-09-01
Embedded instrumentation and control systems that can operate in extreme environments are challenging to design and operate. Extreme environments limit the options for sensors and actuators and degrade their performance. Because sensors and actuators are necessary for feedback control, these limitations mean that designing embedded instrumentation and control systems for the challenging environments of nuclear reactors requires advanced technical solutions that are not available commercially. This report details the development of testbed that will be used for cross-cutting embedded instrumentation and control research for nuclear power applications. This research is funded by the Department of Energy's Nuclear Energy Enabling Technologymore » program's Advanced Sensors and Instrumentation topic. The design goal of the loop-scale testbed is to build a low temperature pump that utilizes magnetic bearing that will be incorporated into a water loop to test control system performance and self-sensing techniques. Specifically, this testbed will be used to analyze control system performance in response to nonlinear and cross-coupling fluid effects between the shaft axes of motion, rotordynamics and gyroscopic effects, and impeller disturbances. This testbed will also be used to characterize the performance losses when using self-sensing position measurement techniques. Active magnetic bearings are a technology that can reduce failures and maintenance costs in nuclear power plants. They are particularly relevant to liquid salt reactors that operate at high temperatures (700 C). Pumps used in the extreme environment of liquid salt reactors provide many engineering challenges that can be overcome with magnetic bearings and their associated embedded instrumentation and control. This report will give details of the mechanical design and electromagnetic design of the loop-scale embedded instrumentation and control testbed.« less
NASA Astrophysics Data System (ADS)
Závada, P.; Desbois, G.; Urai, J. L.; Schulmann, K.; Rahmati, M.; Lexa, O.; Wollenberg, U.
2015-05-01
Viscosity contrasts displayed in flow structures of a mountain namakier (Kuh-e-Namak - Dashti), between 'weak' second phase bearing rock salt and 'strong' pure rock salt types are studied for deformation mechanisms using detailed quantitative microstructural study. While the solid inclusions rich ("dirty") rock salts contain disaggregated siltstone and dolomite interlayers, "clean" salts reveal microscopic hematite and remnants of abundant fluid inclusions in non-recrystallized cores of porphyroclasts. Although the flow in both, the recrystallized "dirty" and "clean" salt types is accommodated by combined mechanisms of pressure-solution creep (PS), grain boundary sliding (GBS), transgranular microcracking and dislocation creep accommodated grain boundary migration (GBM), their viscosity contrasts observed in the field outcrops are explained by: 1) enhanced ductility of "dirty" salts due to increased diffusion rates along the solid inclusion-halite contacts than along halite-halite contacts, and 2) slow rates of intergranular diffusion due to dissolved iron and inhibited dislocation creep due to hematite inclusions for "clean" salt types Rheological contrasts inferred by microstructural analysis between both salt rock classes apply in general for the "dirty" salt forming Lower Hormuz and the "clean" salt forming the Upper Hormuz of the Hormuz Formation and imply strain rate gradients or decoupling along horizons of mobilized salt types of different composition and microstructure.
Performance Analysis of Digital Tracking Loops for Telemetry Ranging Applications
NASA Astrophysics Data System (ADS)
Vilnrotter, V.; Hamkins, J.; Xie, H.; Ashrafi, S.
2015-08-01
In this article, we analyze mathematical models of digital loops used to track the phase and timing of communications and navigation signals. The limits on the accuracy of phase and timing estimates play a critical role in the accuracy achievable in telemetry ranging applications. We describe in detail a practical algorithm to compute the loop parameters for discrete update (DU) and continuous update (CU) loop formulations, and we show that a simple power-series approximation to the DU model is valid over a large range of time-bandwidth product . Several numerical examples compare the estimation error variance of the DU and CU models to each other and to Cramer-Rao lower bounds. Finally, the results are applied to the problem of ranging, by evaluating the performance of a phase-locked loop designed to track a typical ambiguity-resolving pseudonoise (PN) code received and demodulated at the spacecraft on the uplink part of the two-way ranging link, and a data transition tracking loop (DTTL) on the downlink part.
Loop-the-Loop: An Easy Experiment, A Challenging Explanation
NASA Astrophysics Data System (ADS)
Asavapibhop, B.; Suwonjandee, N.
2010-07-01
A loop-the-loop built by the Institute for the Promotion of Teaching Science and Technology (IPST) was used in Thai high school teachers training program to demonstrate a circular motion and investigate the concept of the conservation of mechanical energy. We took videos using high speed camera to record the motions of a spherical steel ball moving down the aluminum inclined track at different released positions. The ball then moved into the circular loop and underwent a projectile motion upon leaving the track. We then asked the teachers to predict the landing position of the ball if we changed the height of the whole loop-the-loop system. We also analyzed the videos using Tracker, a video analysis software. It turned out that most teachers did not realize the effect of the friction between the ball and the track and could not obtain the correct relationship hence their predictions were inconsistent with the actual landing positions of the ball.
One-loop effects of a heavy Higgs boson: A functional approach
DOE Office of Scientific and Technical Information (OSTI.GOV)
Dittmaier, S.; Grosse-Knetter, C.
1995-11-01
We integrate out the Higgs boson in the electroweak standard model at one loop, assuming that it is very heavy. We construct a low-energy effective Lagrangian, which parametrizes the one-loop effect of the heavy Higgs boson at {O}({ital M}{sup O}{sup -}{sub {ital H}}). Instead of applying conventional diagrammatical techniques, we integrate out the Higgs boson directly in the path integral. {copyright} 1995 American Institute of Physics
Loop-the-Loop: Bringing Theory into Practice
ERIC Educational Resources Information Center
Suwonjandee, N.; Asavapibhop, B.
2012-01-01
During the Thai high-school physics teacher training programme, we used an aluminum loop-the-loop system built by the Institute for the Promotion of Teaching Science and Technology (IPST) to demonstrate a circular motion and investigate the concept of the conservation of mechanical energy. There were 27 high-school teachers from three provinces,…
Effective salt criteria in callus-cultured tomato genotypes.
Dogan, Mahmut; Tipirdamaz, Rukiye; Demir, Yavuz
2010-01-01
Na+, Cl-, K+, Ca2+, and proline contents, the rate of lipid peroxidation level in terms of malondialdehyde (MDA) and chlorophyll content, and the changes in the activity of antioxidant enzymes, such as superoxide dismutase (SOD: EC 1.15.1.1), catalase (CAT: EC 1.11.1.6), ascorbate peroxidase (APX: EC 1.11.1.11), and glutathione reductase (GR: EC 1.6.4.2), in tissues of five tomato cultivars in salt tolerance were investigated in a callus culture. The selection of effective parameters used in these tomato genotypes and to find out the use of in vitro tests in place of in vivo salt tolerance tests were investigated. As a material, five different tomato genotypes during a 10-day time period were used, and 150 mM NaCl was applied at callus plant tissue. The exposure to NaCl induced a significant increase in MDA content in both salt-resistant and salt-sensitive cultivars. But the MDA content was higher in salt-sensitive cultivars. The chlorophyll content was more decreased in salt-sensitive than in salt-resistant ones. The proline amount was more increased in salt-sensitive than in salt-resistant ones. It has been reported that salt-tolerant plants, besides being able to regulate the ion and water movements, also exhibit a strong antioxidative enzyme system for effective removal of ROS. The degree of damage depends on the balance between the formation of ROS and its removal by the antioxidative scavenging system that protects against them. Exclusion or inclusion of Na+, Cl-, K+, and Ca2+, antioxidant enzymes and MDA concentration play a key protective role against stress, and this feature at the callus plant tissue used as an identifier for tolerance to salt proved to be an effective criterion.
Salt taste inhibition by cathodal current.
Hettinger, Thomas P; Frank, Marion E
2009-09-28
Effects of cathodal current, which draws cations away from the tongue and drives anions toward the tongue, depend on the ionic content of electrolytes through which the current is passed. To address the role of cations and anions in human salt tastes, cathodal currents of -40 microA to -80 microA were applied to human subjects' tongues through supra-threshold salt solutions. The salts were sodium chloride, sodium bromide, potassium chloride, ammonium chloride, calcium chloride, sodium nitrate, sodium sulfate, sodium saccharin, sodium acetate and sodium benzoate, which taken together encompass salty, bitter, sour and sweet taste qualities. The taste of NaCl, the salty and bitter tastes of the other chloride salts and the taste of NaNO(3) was inhibited, suggesting the current displaced stimulatory cations from salty and bitter receptors. However, bitter tastes of non-halide sodium salts were not inhibited, likely because other bitter receptors respond to anions. A discharge current at cathode-off ubiquitously evoked a metallic taste reminiscent of anodal taste used in clinical electrogustometry. Analogous effects on ambient NaCl responses were recorded from the hamster chorda tympani nerve. Increases in tastes of the saccharin and benzoate anions were not evoked during current flow, suggesting that cathodal current does not carry stimulatory anions to sweet receptors. Cathodal current may selectively inhibit salty and bitter-salty tastes for which proximal stimuli are cations.
Sequence-structure relationships in RNA loops: establishing the basis for loop homology modeling.
Schudoma, Christian; May, Patrick; Nikiforova, Viktoria; Walther, Dirk
2010-01-01
The specific function of RNA molecules frequently resides in their seemingly unstructured loop regions. We performed a systematic analysis of RNA loops extracted from experimentally determined three-dimensional structures of RNA molecules. A comprehensive loop-structure data set was created and organized into distinct clusters based on structural and sequence similarity. We detected clear evidence of the hallmark of homology present in the sequence-structure relationships in loops. Loops differing by <25% in sequence identity fold into very similar structures. Thus, our results support the application of homology modeling for RNA loop model building. We established a threshold that may guide the sequence divergence-based selection of template structures for RNA loop homology modeling. Of all possible sequences that are, under the assumption of isosteric relationships, theoretically compatible with actual sequences observed in RNA structures, only a small fraction is contained in the Rfam database of RNA sequences and classes implying that the actual RNA loop space may consist of a limited number of unique loop structures and conserved sequences. The loop-structure data sets are made available via an online database, RLooM. RLooM also offers functionalities for the modeling of RNA loop structures in support of RNA engineering and design efforts.
Development of the salt-reduction and efficacy-maintenance program in Indonesia.
Irwan, Andi Masyitha; Kato, Mayumi; Kitaoka, Kazuyo; Ueno, Eiichi; Tsujiguchi, Hiromasa; Shogenji, Miho
2016-12-01
We conducted a randomized, controlled trial to examine the effects of a salt-reduction and efficacy-maintenance program on the improvement and maintenance of self-care and self-efficacy in reducing the salt intake of older people with high blood pressure. A total of 51 participants with hypertension/prehypertension in Indonesia were randomly assigned to a control group or one of two intervention groups: salt-reduction training or salt-reduction and efficacy-maintenance. The salt-reduction and efficacy-maintenance group received educational training and a maintenance meeting; the participants' knowledge, attitudes, self-care practices, and self-efficacy significantly improved after training and were maintained after the maintenance meeting. Participants in the salt-reduction training group showed significant effects for the same variables; however, their food salt concentrations rebounded after the maintenance meeting. No significant improvement was found in the control group. The salt-reduction and efficacy-maintenance group participants reported positive effects of salt reduction and different practices based on who prepared their meals. The salt-reduction and efficacy-maintenance group program was effective in improving and maintaining knowledge, attitudes, and self-efficacy of salt-reduction practices and could be applied with community-dwelling older people with high blood pressure. © 2016 John Wiley & Sons Australia, Ltd.
NASA Astrophysics Data System (ADS)
Yang, Chao-Chen; Hsu, Hsin-Yi; Hsu, Chen-Ruei
2007-11-01
In the present work some transport properties of the binary room temperature molten salt (RTMS) lithium bis(trifluoromethane sulfone)imide (LiTFSI)-acetamide [LiN(SO2CF3)2-CH3CONH2], applied in an Li-ion battery, have been investigated. The phase diagram was determined by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The result reveals that the binary RTMS has an eutectic point at 201 K and the 30 mol% LiTFSI composition. The electric conductivity was measured using a direct current computerized method. The result shows that the conductivities of the melts increase with increasing temperature and acetamide content. The densities of all melts decrease with increasing temperature and acetamide content. The equivalent conductivities were fitted by the Arrhenius equation, where the activation energies were 18.15, 18.52, 20.35, 25.08 kJ/mol for 10, 20, 30, 40 mol% LiTFSI, respectively. Besides the relationships between conductivity, density composition and temperature, of the ion interaction is discussed.
Consumer knowledge and attitudes to salt intake and labelled salt information.
Grimes, Carley A; Riddell, Lynn J; Nowson, Caryl A
2009-10-01
The objective of this study was to investigate consumers' knowledge of health risks of high salt intake and frequency of use and understanding of labelled salt information. We conducted a cross-sectional survey in shopping centres within Metropolitan Melbourne. A sample of 493 subjects was recruited. The questionnaire assessed salt related shopping behaviours, attitudes to salt intake and health and their ability to interpret labelled sodium information. Four hundred and seventy four valid surveys were collected (65% female, 64% being the main shopper). Most participants knew of the relationship between salt intake and high blood pressure (88%). Sixty five percent of participants were unable to correctly identify the relationship between salt and sodium. Sixty nine percent reported reading the salt content of food products when shopping. Salt label usage was significantly related to shoppers concern about the amount of salt in their diet and the belief that their health could improve by lowering salt intake. Approximately half of the sample was unable to accurately use labelled sodium information to pick low salt options. Raising consumer awareness of the health risks associated with high salt consumption may increase salt label usage and purchases of low salt foods. However, for food labels to be effective in helping consumers select low salt foods a more 'user friendly' labelling format is needed.
LOOP CALCULUS AND BELIEF PROPAGATION FOR Q-ARY ALPHABET: LOOP TOWER
DOE Office of Scientific and Technical Information (OSTI.GOV)
CHERTKOV, MICHAEL; CHERNYAK, VLADIMIR
Loop calculus introduced in [1], [2] constitutes a new theoretical tool that explicitly expresses symbol Maximum-A-Posteriori (MAP) solution of a general statistical inference problem via a solution of the Belief Propagation (BP) equations. This finding brought a new significance to the BP concept, which in the past was thought of as just a loop-free approximation. In this paper they continue a discussion of the Loop Calculus, partitioning the results into three Sections. In Section 1 they introduce a new formulation of the Loop Calculus in terms of a set of transformations (gauges) that keeping the partition function of the problemmore » invariant. The full expression contains two terms referred to as the 'ground state' and 'excited states' contributions. The BP equations are interpreted as a special (BP) gauge fixing condition that emerges as a special orthogonality constraint between the ground state and excited states, which also selects loop contributions as the only surviving ones among the excited states. In Section 2 they demonstrate how the invariant interpretation of the Loop Calculus, introduced in Section 1, allows a natural extension to the case of a general q-ary alphabet, this is achieved via a loop tower sequential construction. The ground level in the tower is exactly equivalent to assigning one color (out of q available) to the 'ground state' and considering all 'excited' states colored in the remaining (q-1) colors, according to the loop calculus rule. Sequentially, the second level in the tower corresponds to selecting a loop from the previous step, colored in (q-1) colors, and repeating the same ground vs excited states splitting procedure into one and (q-2) colors respectively. The construction proceeds till the full (q-1)-levels deep loop tower (and the corresponding contributions to the partition function) are established. In Section 3 they discuss an ultimate relation between the loop calculus and the Bethe-Free energy variational
Capillary Limit in a Loop Heat Pipe with Dual Evaporators
NASA Technical Reports Server (NTRS)
Ku, Jentung; Birur, Gajanana; Obenschain, Arthur F. (Technical Monitor)
2002-01-01
This paper describes a study on the capillary limit of a loop heat pipe (LHP) with two evaporators and two condensers. Both theoretical analysis and experimental investigation are conducted. Tests include heat load to one evaporator only, even heat loads to both evaporators and uneven heat load to both evaporators. Results show that after the capillary limit is exceeded, vapor will penetrate through the wick of the weaker evaporator and the compensation chamber (CC) of that evaporator will control the loop operating temperature regardless of which CC has been in control prior to the event Because the evaporator can tolerate vapor bubbles, the loop may continue to work and reach a new steady state at a higher operating temperature. The loop may even function with a modest increase in the heat load past the capillary limit With a heat load to only one evaporator, the capillary limit can be identified by rapid increases in the operating temperature and in the temperature difference between the evaporator and the CC. However, it is more difficult to tell when the capillary limit is exceeded if heat loads are applied to both evaporators. In all cases, the loop can recover by reducing the heat load to the loop.
Power Impact of Loop Buffer Schemes for Biomedical Wireless Sensor Nodes
Artes, Antonio; Ayala, Jose L.; Catthoor, Francky
2012-01-01
Instruction memory organisations are pointed out as one of the major sources of energy consumption in embedded systems. As these systems are characterised by restrictive resources and a low-energy budget, any enhancement in this component allows not only to decrease the energy consumption but also to have a better distribution of the energy budget throughout the system. Loop buffering is an effective scheme to reduce energy consumption in instruction memory organisations. In this paper, the loop buffer concept is applied in real-life embedded applications that are widely used in biomedical Wireless Sensor Nodes, to show which scheme of loop buffer is more suitable for applications with certain behaviour. Post-layout simulations demonstrate that a trade-off exists between the complexity of the loop buffer architecture and the energy savings of utilising it. Therefore, the use of loop buffer architectures in order to optimise the instruction memory organisation from the energy efficiency point of view should be evaluated carefully, taking into account two factors: (1) the percentage of the execution time of the application that is related to the execution of the loops, and (2) the distribution of the execution time percentage over each one of the loops that form the application. PMID:23202202
Power impact of loop buffer schemes for biomedical wireless sensor nodes.
Artes, Antonio; Ayala, Jose L; Catthoor, Francky
2012-11-06
Instruction memory organisations are pointed out as one of the major sources of energy consumption in embedded systems. As these systems are characterised by restrictive resources and a low-energy budget, any enhancement in this component allows not only to decrease the energy consumption but also to have a better distribution of the energy budget throughout the system. Loop buffering is an effective scheme to reduce energy consumption in instruction memory organisations. In this paper, the loop buffer concept is applied in real-life embedded applications that are widely used in biomedical Wireless Sensor Nodes, to show which scheme of loop buffer is more suitable for applications with certain behaviour. Post-layout simulations demonstrate that a trade-off exists between the complexity of the loop buffer architecture and the energy savings of utilising it. Therefore, the use of loop buffer architectures in order to optimise the instruction memory organisation from the energy efficiency point of view should be evaluated carefully, taking into account two factors: (1) the percentage of the execution time of the application that is related to the execution of the loops, and (2) the distribution of the execution time percentage over each one of the loops that form the application.
Livermore Compiler Analysis Loop Suite
DOE Office of Scientific and Technical Information (OSTI.GOV)
Hornung, R. D.
2013-03-01
LCALS is designed to evaluate compiler optimizations and performance of a variety of loop kernels and loop traversal software constructs. Some of the loop kernels are pulled directly from "Livermore Loops Coded in C", developed at LLNL (see item 11 below for details of earlier code versions). The older suites were used to evaluate floating-point performances of hardware platforms prior to porting larger application codes. The LCALS suite is geared toward assissing C++ compiler optimizations and platform performance related to SIMD vectorization, OpenMP threading, and advanced C++ language features. LCALS contains 20 of 24 loop kernels from the older Livermoremore » Loop suites, plus various others representative of loops found in current production appkication codes at LLNL. The latter loops emphasize more diverse loop constructs and data access patterns than the others, such as multi-dimensional difference stencils. The loops are included in a configurable framework, which allows control of compilation, loop sampling for execution timing, which loops are run and their lengths. It generates timing statistics for analysis and comparing variants of individual loops. Also, it is easy to add loops to the suite as desired.« less
Investigation of salt loss from the Bonneville Salt Flats, northwestern Utah
Mason, James L.; Kipp, Kenneth L.
1997-01-01
The Bonneville Salt Flats study area is located in the western part of the Great Salt Lake Desert in northwestern Utah, about 110 miles west of Salt Lake City. The salt crust covers about 50 square miles, but the extent varies yearly as a result of salt being dissolved by the formation and movement of surface ponds during the winter and redeposited with the evaporation of these ponds during the summer.A decrease in thickness and extent of the salt crust on the Bonneville Salt Flats has been documented during 1960-88 (S. Brooks, Bureau of Land Management, written commun., 1989). Maximum salt-crust thickness was 7 feet in 1960 and 5.5 feet in 1988. No definitive data are available to identify and quantify the processes that cause salt loss. More than 55 million tons of salt are estimated to have been lost from the salt crust during the 28-year period. The Bureau of Land Management needs to know the causes of salt loss to make appropriate management decisions.
NASA Astrophysics Data System (ADS)
Guo, Shaoqiang; Shay, Nikolas; Wang, Yafei; Zhou, Wentao; Zhang, Jinsuo
2017-12-01
The fluoride molten salt such as FLiNaK and FLiBe is one of the coolant candidates for the next generation nuclear reactor concepts, for example, the fluoride salt cooled high temperature reactor (FHR). For mitigating corrosion of structural materials in molten fluoride salt, the redox condition of the salts needs to be monitored and controlled. This study investigates the feasibility of applying the Eu3+/Eu2+ couple for redox control. Cyclic voltammetry measurements of the Eu3+/Eu2+ couple were able to obtain the concentrations ratio of Eu3+/Eu2+ in the melt. Additionally, the formal standard potential of Eu3+/Eu2+ was characterized over the FHR's operating temperatures allowing for the application of the Nernst equation to establish a Eu3+/Eu2+ concentration ratio below 0.05 to prevent corrosion of candidate structural materials. A platinum quasi-reference electrode with potential calibrated by potassium reduction potential is shown as reliable for the redox potential measurement. These results show that the Eu3+/Eu2+ couple is a feasible redox buffering agent to control the redox condition in molten fluoride salts.
Purification and Chemical Control of Molten Li2BeF 4 for a Fluoride Salt Cooled Reactor
NASA Astrophysics Data System (ADS)
Kelleher, Brian Christopher
Out of the many proposed generation IV, high-temperature reactors, the molten salt reactor (MSR) is one of the most promising. The first large scale MSR, the molten salt reactor experiment (MSRE), operated from 1965 to 1969 using Li2BeF4, or flibe, as a coolant and solvent for uranium fluoride fuel, at maximum temperatures of 654°C, for over 15000 hours. The MSRE experienced no concept breaking surprises and was considered a success. Newly proposed designs of molten salt reactors use solid fuels, making them less exotic compared to the MSRE. However, any molten salt reactor will require a great deal of research pertaining to the chemical and mechanical mastery of molten salts in order to prepare it for commercialization. To supplement the development of new molten salt reactors, approximately 100 kg of flibe was purified using the standard hydrofluorination process. Roughly half of the purified salt was lithium-7 enriched salt from the secondary loop of the MSRE. Purification rids the salt of impurities and reduces its capacity for corrosion, also known as the redox potential. The redox potential of flibe was measured at various stages of purification for the first time using a dynamic beryllium reference electrode. These redox measurements have been superimposed with metal impurities measurements found by neutron activation analysis. Lastly, reductions of flibe with beryllium metal have been investigated. Over reductions have been performed, which have shown to decrease redox potential while seemingly creating a beryllium-beryllium halide system. Recommendations of the lowest advisable redox potential for corrosion tests are included along with suggestions for future work.
Introduction to Loop Heat Pipes
NASA Technical Reports Server (NTRS)
Ku, Jentung
2015-01-01
This is the presentation file for the short course Introduction to Loop Heat Pipes, to be conducted at the 2015 Thermal Fluids and Analysis Workshop, August 3-7, 2015, Silver Spring, Maryland. This course will discuss operating principles and performance characteristics of a loop heat pipe. Topics include: 1) pressure profiles in the loop; 2) loop operating temperature; 3) operating temperature control; 4) loop startup; 4) loop shutdown; 5) loop transient behaviors; 6) sizing of loop components and determination of fluid inventory; 7) analytical modeling; 8) examples of flight applications; and 9) recent LHP developments.
Damping of Loop Oscillations in the Stratified Corona
NASA Astrophysics Data System (ADS)
Erdélyi, R.; Mendoza-Briceño, C. A.
2004-01-01
SOHO and TRACE observations have confirmed the theoretical predictions by Roberts et al. (1984) almost two solar cycles ago, namely, coronal loops may oscillate. These oscillations, and in particular their damping, are of fundamental importance for solar physics since they can provide diagnostics of the plasma medium. In the present paper we apply this concept to hot and stratified and nonisothermal coronal loops observed by e.g. TRACE or SUMER on-board SOHO. We investigate the effect of stratification on (i) the damping of standing waves and (ii) on propagating coherent disturbances (i.e. basically slow MHD waves). The effect of stratification results, if we may say so, in an approximate 15-20% of reduction in damping time for the parameter regime that characterise hot SUMER or TRACE loops. This is a good news as theoretical speculations in the literature usually suffer from an over-estimate of the damping of oscillations caused by e.g. thermal conduction or viscosity in the non-stratified atmosphere approach.
On a Continuum Limit for Loop Quantum Cosmology
DOE Office of Scientific and Technical Information (OSTI.GOV)
Corichi, Alejandro; Center for Fundamental Theory, Institute for Gravitation and the Cosmos, Pennsylvania State University, University Park PA 16802; Vukasinac, Tatjana
2008-03-06
The use of non-regular representations of the Heisenberg-Weyl commutation relations has proved to be useful for studying conceptual and technical issues in quantum gravity. Of particular relevance is the study of Loop Quantum Cosmology (LQC), symmetry reduced theory that is related to Loop Quantum Gravity, and that is based on a non-regular, polymeric representation. Recently, a soluble model was used by Ashtekar, Corichi and Singh to study the relation between Loop Quantum Cosmology and the standard Wheeler-DeWitt theory and, in particular, the passage to the limit in which the auxiliary parameter (interpreted as ''quantum geometry discreetness'') is sent to zeromore » in hope to get rid of this 'regulator' that dictates the LQC dynamics at each 'scale'. In this note we outline the first steps toward reformulating this question within the program developed by the authors for studying the continuum limit of polymeric theories, which was successfully applied to simple systems such as a Simple Harmonic Oscillator.« less
Techniques, analysis, and noise in a Salt Lake Valley 4D gravity experiment
Gettings, P.; Chapman, D.S.; Allis, R.
2008-01-01
Repeated high-precision gravity measurements using an automated gravimeter and analysis of time series of 1-Hz samples allowed gravity measurements to be made with an accuracy of 5 ??Gal or better. Nonlinear instrument drift was removed using a new empirical staircase function built from multiple station loops. The new technique was developed between March 1999 and September 2000 in a pilot study conducted in the southern Salt Lake Valley along an east-west profile of eight stations from the Wasatch Mountains to the Jordan River. Gravity changes at eight profile stations were referenced to a set of five stations in the northern Salt Lake Valley, which showed residual signals of <10 ??Gal in amplitude, assuming a reference station near the Great Salt Lake to be stable. Referenced changes showed maximum amplitudes of -40 through +40 ??Gal at profile stations, with minima in summer 1999, maxima in winter 1999-2000, and some decrease through summer 2000. Gravity signals were likely a composite of production-induced changes monitored by well-water levels, elevation changes, precipitation-induced vadose-zone changes, and local irrigation effects for which magnitudes were estimated quantitatively. ?? 2008 Society of Exploration Geophysicists. All rights reserved.
Steady-state phase error for a phase-locked loop subjected to periodic Doppler inputs
NASA Technical Reports Server (NTRS)
Chen, C.-C.; Win, M. Z.
1991-01-01
The performance of a carrier phase locked loop (PLL) driven by a periodic Doppler input is studied. By expanding the Doppler input into a Fourier series and applying the linearized PLL approximations, it is easy to show that, for periodic frequency disturbances, the resulting steady state phase error is also periodic. Compared to the method of expanding frequency excursion into a power series, the Fourier expansion method can be used to predict the maximum phase error excursion for a periodic Doppler input. For systems with a large Doppler rate fluctuation, such as an optical transponder aboard an Earth orbiting spacecraft, the method can be applied to test whether a lower order tracking loop can provide satisfactory tracking and thereby save the effect of a higher order loop design.
NASA Astrophysics Data System (ADS)
Sever, Amit; Vieira, Pedro; Wang, Tianheng
2011-11-01
We extend the Operator Product Expansion for Null Polygon Wilson loops to the Mason-Skinner-Caron-Huot super loop dual to non MHV gluon amplitudes. We explain how the known tree level amplitudes can be promoted into an infinite amount of data at any loop order in the OPE picture. As an application, we re-derive all one loop NMHV six gluon amplitudes by promoting their tree level expressions. We also present some new all loops predictions for these amplitudes.
Effect of supercoiling on formation of protein-mediated DNA loops
NASA Astrophysics Data System (ADS)
Purohit, P. K.; Nelson, P. C.
2006-12-01
DNA loop formation is one of several mechanisms used by organisms to regulate genes. The free energy of forming a loop is an important factor in determining whether the associated gene is switched on or off. In this paper we use an elastic rod model of DNA to determine the free energy of forming short (50-100 basepair), protein mediated DNA loops. Superhelical stress in the DNA of living cells is a critical factor determining the energetics of loop formation, and we explicitly account for it in our calculations. The repressor protein itself is regarded as a rigid coupler; its geometry enters the problem through the boundary conditions it applies on the DNA. We show that a theory with these ingredients is sufficient to explain certain features observed in modulation of in vivo gene activity as a function of the distance between operator sites for the lac repressor. We also use our theory to make quantitative predictions for the dependence of looping on superhelical stress, which may be testable both in vivo and in single-molecule experiments such as the tethered particle assay and the magnetic bead assay.
Ortho stops marketing Lippes Loop; cites economic factors.
1985-11-01
Ortho Pharmaceutical Corporation has stopped marketing the Lippes Loop IUD, the only inert IUD currently available in the US. The firm cited "economic considerations" as its reason. Linda Organ, company spokeswoman, told Contraceptive Technology Update (CTU) that the number of women using IUDs has declined in the past few years and, as a result, Ortho's Lippes Loop sales dropped. Most physicians, according to Organ, currently prescribe copper-bearing IUDs. Few devices have been studied as thoroughly before marketing as the Lippes Loop, according to its developer, Dr. Jack Lippes. Lippes told CTU that the Population Council analyzed 40,000 women from 1962 to 1968 and "found no trouble with the Loop." Lippes attributes Ortho's recent decision to 2 factors: the IUD has been only "marginally profitable" and the problems of A.H. Robins with the Dalkon Shield has most likely had an effect; and the US Food and Drug Administration (FDA) published a proposed rule in August 1985 that would require any company wanting to manufacture and market IUDs like the Lippes Loop to submit a premarketing approval application to that agency. In effect, the FDA's rule would only apply to the Lippes Loop. Under the proposed rule, any company wanting to market Lippes Loops, or any nondrug IUD, would have to submit an application to the FDA with a detailed discussion and supporting clinical studies addressing the following concerns: pelvic actinomycosis; tubal infertility; duration that the IUD should remain in situ; and safety of leaving the IUD in situ when contraception is no longer indicated. According to Lillian Yin, FDA device evaluation, the clinical effectiveness and most of the safety issues regarding inert IUDs have been thoroughly covered in published data. She told CTU that "most of the information needed is straightforward, but the part that's new involves the long term use infection rate." Yin indicated that the FDA received a letter from Ortho advising the agency of the
been characterized include: (1) mesomeric phosphonium salts possessing phototropic properties; (2) pentavalent phosphorus compounds; and (3) a...Products that have been characterized include: (1) mesomeric phosphonium salts possessing phototropic properties; (2) pentavalent phosphorus compounds; and (3) a mesomeric inner salt. (Author)
Improving crop salt tolerance.
Flowers, T J
2004-02-01
Salinity is an ever-present threat to crop yields, especially in countries where irrigation is an essential aid to agriculture. Although the tolerance of saline conditions by plants is variable, crop species are generally intolerant of one-third of the concentration of salts found in seawater. Attempts to improve the salt tolerance of crops through conventional breeding programmes have met with very limited success, due to the complexity of the trait: salt tolerance is complex genetically and physiologically. Tolerance often shows the characteristics of a multigenic trait, with quantitative trait loci (QTLs) associated with tolerance identified in barley, citrus, rice, and tomato and with ion transport under saline conditions in barley, citrus and rice. Physiologically salt tolerance is also complex, with halophytes and less tolerant plants showing a wide range of adaptations. Attempts to enhance tolerance have involved conventional breeding programmes, the use of in vitro selection, pooling physiological traits, interspecific hybridization, using halophytes as alternative crops, the use of marker-aided selection, and the use of transgenic plants. It is surprising that, in spite of the complexity of salt tolerance, there are commonly claims in the literature that the transfer of a single or a few genes can increase the tolerance of plants to saline conditions. Evaluation of such claims reveals that, of the 68 papers produced between 1993 and early 2003, only 19 report quantitative estimates of plant growth. Of these, four papers contain quantitative data on the response of transformants and wild-type of six species without and with salinity applied in an appropriate manner. About half of all the papers report data on experiments conducted under conditions where there is little or no transpiration: such experiments may provide insights into components of tolerance, but are not grounds for claims of enhanced tolerance at the whole plant level. Whether enhanced
Conformal blocks from Wilson lines with loop corrections
NASA Astrophysics Data System (ADS)
Hikida, Yasuaki; Uetoko, Takahiro
2018-04-01
We compute the conformal blocks of the Virasoro minimal model or its WN extension with large central charge from Wilson line networks in a Chern-Simons theory including loop corrections. In our previous work, we offered a prescription to regularize divergences from loops attached to Wilson lines. In this paper, we generalize our method with the prescription by dealing with more general operators for N =3 and apply it to the identity W3 block. We further compute general light-light blocks and heavy-light correlators for N =2 with the Wilson line method and compare the results with known ones obtained using a different prescription. We briefly discuss general W3 blocks.
CORROSION STUDIES FOR A FUSED SALT-LIQUID METAL EXTRACTION PROCESS FOR THE LIQUID METAL FUEL REACTOR
DOE Office of Scientific and Technical Information (OSTI.GOV)
Susskind, H.; Hill, F.B.; Green, L.
1960-06-30
Corrosion screening tests were carried out on potential materials of construction for use in a fused salt-liquid metal extraction process plant. The corrodents of interest were NaCl--KCl-- MgCl/sub 2/ eutectic, LiCl--KCl eutectic, Bi-- U fuel, and BiCl/sub 3/, either separately or in various combinations. Screening tests to determine the resistance of a wide range of commercial alloys to the corrodents were performed in static and tilting-furnace capsules. Some ceramic materials were tested in static capsules. Largerscale tests of metallic materials were conducted in thermal convection loops and in a forced circulation loop. Some of the tests were conducted isothermally atmore » 500 deg C, and others were performed under 40 to 50 deg C temperature differences at roughly the same teinperature level. On the basis of metallographic examination of exposed test tabs and chemical analyses of corrodents, it was found that the binary and ternary eutectics by themselves produced little attack on any of the materials tested. A wide variety of materials including 1020 mild steel, 2 1/4 Cr--1 Mo alloy steel, types 304 (ELC), 310, 316, 347, 430, and 446 stainless steel, 16-1 Croloy, Inconel, Hastelloy C, Inor-8, Mo, and Ta is, therefore, available for further study. Corrosion by the ternary salt-fuel system was characteristic of that produced by the fuel alone. Alloys such as 1020 mild steel, and 1 1/4 Cr--1/ 2 Mo, and 2 1/4 Cr--1 Mo alloy steel, which are resistant to fuel, would be likely choices at present for container materials. BiCl/sub 3/ produced extensive attack on ternary salt-fuel containers when the fuel contained insufficient concentrations of oxidizable solutes. Au and Al/sub 2/O/sub 3/ were the only materials not attacked by BiCl/sub 3/ in ternary salt alone. (auth)« less
Thermal-hydraulics of internally heated molten salts and application to the Molten Salt Fast Reactor
NASA Astrophysics Data System (ADS)
Fiorina, Carlo; Cammi, Antonio; Luzzi, Lelio; Mikityuk, Konstantin; Ninokata, Hisashi; Ricotti, Marco E.
2014-04-01
The Molten Salt Reactors (MSR) are an innovative kind of nuclear reactors and are presently considered in the framework of the Generation IV International Forum (GIF-IV) for their promising performances in terms of low resource utilization, waste minimization and enhanced safety. A unique feature of MSRs is that molten fluoride salts play the distinctive role of both fuel (heat source) and coolant. The presence of an internal heat generation perturbs the temperature field and consequences are to be expected on the heat transfer characteristics of the molten salts. In this paper, the problem of heat transfer for internally heated fluids in a straight circular channel is first faced on a theoretical ground. The effect of internal heat generation is demonstrated to be described by a corrective factor applied to traditional correlations for the Nusselt number. It is shown that the corrective factor can be fully characterized by making explicit the dependency on Reynolds and Prandtl numbers. On this basis, a preliminary correlation is proposed for the case of molten fluoride salts by interpolating the results provided by an analytic approach previously developed at the Politecnico di Milano. The experimental facility and the related measuring procedure for testing the proposed correlation are then presented. Finally, the developed correlation is used to carry out a parametric investigation on the effect of internal heat generation on the main out-of-core components of the Molten Salt Fast Reactor (MSFR), the reference circulating-fuel MSR design in the GIF-IV. The volumetric power determines higher temperatures at the channel wall, but the effect is significant only in case of large diameters and/or low velocities.
NASA Astrophysics Data System (ADS)
Gaggioli, Walter; Di Ascenzi, Primo; Rinaldi, Luca; Tarquini, Pietro; Fabrizi, Fabrizio
2016-05-01
In the frame of the Solar Thermodynamic Laboratory, ENEA has improved CSP Parabolic Trough technologies by adopting new advanced solutions for linear tube receivers and by implementing a binary mixture of molten salt (60% NaNO3 and 40% KNO3) [1] as both heat transfer fluid and heat storage medium in solar field and in storage tanks, thus allowing the solar plants to operate at high temperatures up to 550°C. Further improvements have regarded parabolic mirror collectors, piping and process instrumentation. All the innovative components developed by ENEA, together with other standard parts of the plant, have been tested and qualified under actual solar operating conditions on the PCS experimental facility at the ENEA Casaccia Research Center in Rome (Italy). The PCS (Prova Collettori Solari, i.e. Test of Solar Collectors) facility is the main testing loop built by ENEA and it is unique in the world for what concerns the high operating temperature and the fluid used (mixture of molten salt). It consists in one line of parabolic trough collectors (test section of 100 m long life-size solar collectors) using, as heat transfer fluid, the aforesaid binary mixture of molten salt up to 10 bar, at high temperature in the range 270° and 550°C and a flow rate up to 6.5 kg/s. It has been working since early 2004 [2] till now; it consists in a unique closed loop, and it is totally instrumented. In this paper the effects of over ten years qualification tests on the pressurized tank will be presented, together with the characterization of the thermal losses of the piping of the molten salt circuit, and some observations performed on the PCS facility during its first ten years of operation.
Molten salt oxidation of organic hazardous waste with high salt content.
Lin, Chengqian; Chi, Yong; Jin, Yuqi; Jiang, Xuguang; Buekens, Alfons; Zhang, Qi; Chen, Jian
2018-02-01
Organic hazardous waste often contains some salt, owing to the widespread use of alkali salts during industrial manufacturing processes. These salts cause complications during the treatment of this type of waste. Molten salt oxidation is a flameless, robust thermal process, with inherent capability of destroying the organic constituents of wastes, while retaining the inorganic ingredients in the molten salt. In the present study, molten salt oxidation is employed for treating a typical organic hazardous waste with a high content of alkali salts. The hazardous waste derives from the production of thiotriazinone. Molten salt oxidation experiments have been conducted using a lab-scale molten salt oxidation reactor, and the emissions of CO, NO, SO 2 , HCl and dioxins are studied. Impacts are investigated from the composition of the molten salts, the types of feeding tube, the temperature of molten carbonates and the air factor. Results show that the waste can be oxidised effectively in a molten salt bath. Temperature of molten carbonates plays the most important role. With the temperature rising from 600 °C to 750 °C, the oxidation efficiency increases from 91.1% to 98.3%. Compared with the temperature, air factor has but a minor effect, as well as the composition of the molten salts and the type of feeding tube. The molten carbonates retain chlorine with an efficiency higher than 99.9% and the emissions of dioxins are below 8 pg TEQ g -1 sample. The present study shows that molten salt oxidation is a promising alternative for the disposal of organic hazardous wastes containing a high salt content.
Optical phase locked loop for transparent inter-satellite communications.
Herzog, F; Kudielka, K; Erni, D; Bächtold, W
2005-05-16
A novel type of optical phase locked loop (OPLL), optimized for homodyne inter-satellite communication, is presented. The loop employs a conventional 180? 3 dB optical hybrid and an AC-coupled balanced front end. No residual carrier transmission is required for phase locking. The loop accepts analog as well as digital data and various modulation formats. The only requirement to the transmitted user signal is a constant envelope. Phase error extraction occurs through applying a small sinusoidal local oscillator (LO) phase disturbance, while measuring its impact on the power of the baseband output signal. First experimental results indicate a receiver sensitivity of 36 photons/bit (-55.7 dBm) for a BER of 10 ;-9, when transmitting a PRBS-31 signal at a data rate of 400 Mbit/s. The system setup employs diode-pumped Nd:YAG lasers at a wavelength of 1.06 mum.
Optical phase locked loop for transparent inter-satellite communications
NASA Astrophysics Data System (ADS)
Herzog, F.; Kudielka, K.; Erni, D.; Bächtold, W.
2005-05-01
A novel type of optical phase locked loop (OPLL), optimized for homodyne inter-satellite communication, is presented. The loop employs a conventional 180◦ 3 dB optical hybrid and an AC-coupled balanced front end. No residual carrier transmission is required for phase locking. The loop accepts analog as well as digital data and various modulation formats. The only requirement to the transmitted user signal is a constant envelope. Phase error extraction occurs through applying a small sinusoidal local oscillator (LO) phase disturbance, while measuring its impact on the power of the baseband output signal. First experimental results indicate a receiver sensitivity of 36 photons/bit (-55.7 dBm) for a BER of 10 ^-9, when transmitting a PRBS-31 signal at a data rate of 400 Mbit/s. The system setup employs diode-pumped Nd:YAG lasers at a wavelength of 1.06 μm.
Strnad, Marija
2010-05-01
Besides cardiovascular disease, a high salt intake causes other adverse health effects, i.e., gastric and some other cancers, obesity (risk factor for many cancer sites), Meniere's disease, worsening of renal disease, triggering an asthma attack, osteoporosis, exacerbation of fluid retention, renal calculi, etc. Diets containing high amounts of food preserved by salting and pickling are associated with an increased risk of cancers of the stomach, nose and throat. Because gastric cancer is still the most common cancer in some countries (especially in Japan), its prevention is one of the most important aspects of cancer control strategy. Observations among Japanese immigrants in the U.S.A. and Brazil based on the geographic differences, the trend in cancer incidence with time, and change in the incidence patterns indicate that gastric cancer is closely associated with dietary factors such as the intake of salt and salted food. The findings of many epidemiological studies suggest that high dietary salt intake is a significant risk factor for gastric cancer and this association was found to be strong in the presence of Helicobacter (H.) pylori infection with atrophic gastritis. A high-salt intake strips the lining of the stomach and may make infection with H. pylori more likely or may exacerbate the infection. Salting, pickling and smoking are traditionally popular ways of preparing food in Japan and some parts of Asia. In addition to salt intake, cigarette smoking and low consumption of fruit and vegetables increase the risk of stomach cancer. However, it is not known whether it is specifically the salt in these foods or a combination of salt and other chemicals that can cause cancer. One study identified a mutagen in nitrite-treated Japanese salted fish, and chemical structure of this mutagen suggests that it is derived from methionine and that salt and nitrite are precursors for its formation. Working under conditions of heat stress greatly increased the workers
Video-Growing Salt Crystals Onboard the International Space Station (ISS)
NASA Technical Reports Server (NTRS)
2003-01-01
Saturday Morning Science, the science of opportunity series of applied experiments and demonstrations, performed aboard the International Space Station (ISS) by Expedition 6 astronaut Dr. Don Pettit, revealed some remarkable findings. Growing salt crystals in a bottle of water is a favorite science activity for kids. In space, Dr. Pettit grew salt crystals in stretched films of water so that the salt water only fed the crystals around the edges rather than from all sides, as happens in a glass of water. This video of his demonstration shows that surface tension plays a surprisingly dominant role in the crystal formation and convection is more active that one might expect.
Public Notice 2018-04. Morton Salt Inc.
Morton Salt, Inc., 123 North Walker Dr., Chicago, IL 60606 has applied to the U.S. Environmental Protection Agency (EPA) under the provisions of the Safe Drinking Water Act, 42 U.S.C. 300f et. seq (the Act), for a new Underground Injection Control (UIC) pe
Closed loop cavitation control - A step towards sonomechatronics.
Saalbach, Kai-Alexander; Ohrdes, Hendrik; Twiefel, Jens
2018-06-01
In the field of sonochemistry, many processes are made possible by the generation of cavitation. This article is about closed loop control of ultrasound assisted processes with the aim of controlling the intensity of cavitation-based sonochemical processes. This is the basis for a new research field which the authors call "sonomechatronics". In order to apply closed loop control, a so called self-sensing technique is applied, which uses the ultrasound transducer's electrical signals to gain information about cavitation activity. Experiments are conducted to find out if this self-sensing technique is capable of determining the state and intensity of acoustic cavitation. A distinct frequency component in the transducer's current signal is found to be a good indicator for the onset and termination of transient cavitation. Measurements show that, depending on the boundary conditions, the onset and termination of transient cavitation occur at different thresholds, with the onset occurring at a higher value in most cases. This known hysteresis effect offers the additional possibility of achieving an energetic optimization by controlling cavitation generation. Using the cavitation indicator for the implementation of a double set point closed loop control, the mean driving current was reduced by approximately 15% compared to the value needed to exceed the transient cavitation threshold. The results presented show a great potential for the field of sonomechatronics. Nevertheless, further investigations are necessary in order to design application-specific sonomechatronic processes. Copyright © 2018 Elsevier B.V. All rights reserved.
Limit Cycle Bifurcations by Perturbing a Piecewise Hamiltonian System with a Double Homoclinic Loop
NASA Astrophysics Data System (ADS)
Xiong, Yanqin
2016-06-01
This paper is concerned with the bifurcation problem of limit cycles by perturbing a piecewise Hamiltonian system with a double homoclinic loop. First, the derivative of the first Melnikov function is provided. Then, we use it, together with the analytic method, to derive the asymptotic expansion of the first Melnikov function near the loop. Meanwhile, we present the first coefficients in the expansion, which can be applied to study the limit cycle bifurcation near the loop. We give sufficient conditions for this system to have 14 limit cycles in the neighborhood of the loop. As an application, a piecewise polynomial Liénard system is investigated, finding six limit cycles with the help of the obtained method.
Ovečka, Miroslav; Takáč, Tomáš; Komis, George; Vadovič, Pavol; Bekešová, Slávka; Doskočilová, Anna; Šamajová, Veronika; Luptovčiak, Ivan; Samajová, Olga; Schweighofer, Alois; Meskiene, Irute; Jonak, Claudia; Křenek, Pavel; Lichtscheidl, Irene; Škultéty, L'udovít; Hirt, Heribert; Šamaj, Jozef
2014-06-01
Dual-specificity mitogen-activated protein kinases kinases (MAPKKs) are the immediate upstream activators of MAPKs. They simultaneously phosphorylate the TXY motif within the activation loop of MAPKs, allowing them to interact with and regulate multiple substrates. Often, the activation of MAPKs triggers their nuclear translocation. However, the spatiotemporal dynamics and the physiological consequences of the activation of MAPKs, particularly in plants, are still poorly understood. Here, we studied the activation and localization of the Medicago sativa stress-induced MAPKK (SIMKK)-SIMK module after salt stress. In the inactive state, SIMKK and SIMK co-localized in the cytoplasm and in the nucleus. Upon salt stress, however, a substantial part of the nuclear pool of both SIMKK and SIMK relocated to cytoplasmic compartments. The course of nucleocytoplasmic shuttling of SIMK correlated temporally with the dual phosphorylation of the pTEpY motif. SIMKK function was further studied in Arabidopsis plants overexpressing SIMKK-yellow fluorescent protein (YFP) fusions. SIMKK-YFP plants showed enhanced activation of Arabidopsis MPK3 and MPK6 kinases upon salt treatment and exhibited high sensitivity against salt stress at the seedling stage, although they were salt insensitive during seed germination. Proteomic analysis of SIMKK-YFP overexpressors indicated the differential regulation of proteins directly or indirectly involved in salt stress responses. These proteins included catalase, peroxiredoxin, glutathione S-transferase, nucleoside diphosphate kinase 1, endoplasmic reticulum luminal-binding protein 2, and finally plasma membrane aquaporins. In conclusion, Arabidopsis seedlings overexpressing SIMKK-YFP exhibited higher salt sensitivity consistent with their proteome composition and with the presumptive MPK3/MPK6 hijacking of the salt response pathway. © The Author 2014. Published by Oxford University Press on behalf of the Society for Experimental Biology.
A molten Salt Am242M Production Reactor for Space Applications
NASA Technical Reports Server (NTRS)
Emrich, William
2005-01-01
The use of Am242m holds great promise for increasing the efficiency nuclear thermal rocket engines. Because Am242m has the highest fission cross section of any known isotope (1000's of barns), its extremely high reactivity may be used to directly heat a propellant gas with fission fragments. Since this isotope does not occur naturally, it must be bred in special production reactors designed for that purpose. The primary advantage to using molten salt reactors for breeding Am242m is that the reactors can be reprocessed continually yielding a constant rate of production of the isotope. Once built and initially fueled, the reactor will continually breed the additional fuel it needs to remain critical. The only feedstock required is a salt of U238. No enriched fuel is required during normal operation and all fissile material, except the Am242m, is maintained in a closed loop. For a reactor operating at 200 MW several kilograms of Am242m may be bred each year.
An Implementation of the Salt-Farm Monitoring System Using Wireless Sensor Network
NASA Astrophysics Data System (ADS)
Ju, Jonggil; Park, Ingon; Lee, Yongwoong; Cho, Jongsik; Cho, Hyunwook; Yoe, Hyun; Shin, Changsun
In producing solar salt, natural environmental factors such as temperature, humidity, solar radiation, wind direction, wind speed and rain are essential elements which influence on the productivity and quality of salt. If we can manage the above mentioned environmental elements efficiently, we could achieve improved results in production of salt with good quality. To monitor and manage the natural environments, this paper suggests the Salt-Farm Monitoring System (SFMS) which is operated with renewable energy power. The system collects environmental factors directly from the environmental measure sensors and the sensor nodes. To implement a stand-alone system, we applied solar cell and wind generator to operate this system. Finally, we showed that the SFMS could monitor the salt-farm environments by using wireless sensor nodes and operate correctly without external power supply.
Double closed-loop cascade control for lower limb exoskeleton with elastic actuation.
Zhu, Yanhe; Zheng, Tianjiao; Jin, Hongzhe; Yang, Jixing; Zhao, Jie
2015-01-01
Unlike traditional rigid actuators, the significant features of Series Elastic Actuator (SEA) are stable torque control, lower output impedance, impact resistance and energy storage. Recently, SEA has been applied in many exoskeletons. In such applications, a key issue is how to realize the human-exoskeleton movement coordination. In this paper, double closed-loop cascade control for lower limb exoskeleton with SEA is proposed. This control method consists of inner SEA torque loop and outer contact force loop. Utilizing the SEA torque control with a motor velocity loop, actuation performances of SEA are analyzed. An integrated exoskeleton control system is designed, in which joint angles are calculated by internal encoders and resolvers and contact forces are gathered by external pressure sensors. The double closed-loop cascade control model is established based on the feedback signals of internal and external sensor. Movement experiments are accomplished in our prototype of lower limb exoskeleton. Preliminary results indicate the exoskeleton movements with pilot can be realized stably by utilizing this double closed-loop cascade control method. Feasibility of the SEA in our exoskeleton robot and effectiveness of the control method are verified.
Multiple Flow Loop SCADA System Implemented on the Production Prototype Loop
DOE Office of Scientific and Technical Information (OSTI.GOV)
Baily, Scott A.; Dalmas, Dale Allen; Wheat, Robert Mitchell
2015-11-16
The following report covers FY 15 activities to develop supervisory control and data acquisition (SCADA) system for the Northstar Moly99 production prototype gas flow loop. The goal of this effort is to expand the existing system to include a second flow loop with a larger production-sized blower. Besides testing the larger blower, this system will demonstrate the scalability of our solution to multiple flow loops.
Profiling Groundwater Salt Concentrations in Mangrove Swamps and Tropical Salt Flats
NASA Astrophysics Data System (ADS)
Ridd, Peter V.; Sam, Renagi
1996-11-01
The salt concentration of groundwater in mangrove swamps is an important parameter controlling the growth of mangrove species. Extremely high salt concentrations of groundwater in tropical salt flats are responsible for the complete absence of macrophytes. Determining groundwater salt concentrations can be a very time-consuming and laborious process if conventional techniques are used. Typically, groundwater samples must be extracted for later laboratory analysis. In this work, a simple conductivity probe has been developed which may be inserted easily to a depth of 2 m into the sediment. The changes in conductivity of the sediment is due primarily to porewater salt concentration, and thus ground conductivity is useful in determining changes in groundwater salt concentrations. Using the conductivity probe, transects of sediment conductivity can be undertaken quickly. As an example of a possible application of the probe, transects of ground conductivity were taken on a mangrove swamp/saltflat system. The transects show clearly the sharp delineation in conductivity between the salt flat and mangrove swamp due to a change in groundwater salt concentrations. Horizontal and vertical salt concentration gradients of up to 50 g l -1 m -1and 150 g l -1 m -1, respectively, were found. Very sharp changes in groundwater salt concentrations at the interface between salt flats and mangroves indicate that the mangroves may be modifying the salinity of the groundwater actively.
Material Data Representation of Hysteresis Loops for Hastelloy X Using Artificial Neural Networks
NASA Technical Reports Server (NTRS)
Alam, Javed; Berke, Laszlo; Murthy, Pappu L. N.
1993-01-01
The artificial neural network (ANN) model proposed by Rumelhart, Hinton, and Williams is applied to develop a functional approximation of material data in the form of hysteresis loops from a nickel-base superalloy, Hastelloy X. Several different ANN configurations are used to model hysteresis loops at different cycles for this alloy. The ANN models were successful in reproducing the hysteresis loops used for its training. However, because of sharp bends at the two ends of hysteresis loops, a drift occurs at the corners of the loops where loading changes to unloading and vice versa (the sharp bends occurred when the stress-strain curves were reproduced by adding stress increments to the preceding values of the stresses). Therefore, it is possible only to reproduce half of the loading path. The generalization capability of the network was tested by using additional data for two other hysteresis loops at different cycles. The results were in good agreement. Also, the use of ANN led to a data compression ratio of approximately 22:1.
Protonation of inorganic 5-Fluorocytosine salts
NASA Astrophysics Data System (ADS)
Souza, Matheus S.; da Silva, Cecília C. P.; Almeida, Leonardo R.; Diniz, Luan F.; Andrade, Marcelo B.; Ellena, Javier
2018-06-01
5-Fluorocytosine (5-FC) has been widely used for the treatment of fungal infections and recently was found to exert an extraordinary antineoplastic activity in gene directed prodrug therapy. However, despite of its intense use, 5-FC exhibits tabletability issues due its physical instability in humid environments, leading to transition from the anhydrous to monohydrate phase. By considering that salt formation is an interesting strategy to overcome this problem, in this paper crystal engineering approach was applied to the supramolecular synthesis of new 5-FC salts with sulfuric, hydrobromic and methanesulfonic inorganic acids. A total of four structures were obtained, namely 5-FC sulfate monohydrate (1:1:1), 5-FC hydrogen sulfate (1:1), 5-FC mesylate (1:1) and 5-FC hydrobromide (1:1), the last one being a polymorphic form of a structure already reported in the literature. These novel salts were structurally characterized by single crystal X-ray diffraction and its supramolecular organization were analyses by Hirshfeld surface analysis. The vibrational behavior was evaluated by Raman spectroscopy and it was found to be consistent with the crystal structures.
A systematic and efficient method to compute multi-loop master integrals
NASA Astrophysics Data System (ADS)
Liu, Xiao; Ma, Yan-Qing; Wang, Chen-Yu
2018-04-01
We propose a novel method to compute multi-loop master integrals by constructing and numerically solving a system of ordinary differential equations, with almost trivial boundary conditions. Thus it can be systematically applied to problems with arbitrary kinematic configurations. Numerical tests show that our method can not only achieve results with high precision, but also be much faster than the only existing systematic method sector decomposition. As a by product, we find a new strategy to compute scalar one-loop integrals without reducing them to master integrals.
Assessing the Wildlife Habitat Value of New England Salt Marshes: I. Model and Application
We developed an assessment model to quantify the wildlife habitat value of New England salt marshes based on marsh characteristics and the presence of habitat types that influence habitat use by terrestrial wildlife. Applying the model to12 salt marshes located in Narragansett B...
How Do Changes to the Railroad Causeway in Utah's Great Salt Lake Affect Water and Salt Flow?
White, James S; Null, Sarah E; Tarboton, David G
2015-01-01
Managing terminal lake elevation and salinity are emerging problems worldwide. We contribute to terminal lake management research by quantitatively assessing water and salt flow for Utah's Great Salt Lake. In 1959, Union Pacific Railroad constructed a rock-filled causeway across the Great Salt Lake, separating the lake into a north and south arm. Flow between the two arms was limited to two 4.6 meter wide rectangular culverts installed during construction, an 88 meter opening (referred to locally as a breach) installed in 1984, and the semi porous material of the causeway. A salinity gradient developed between the two arms of the lake over time because the south arm receives approximately 95% of the incoming streamflow entering Great Salt Lake. The north arm is often at, or near, salinity saturation, averaging 317 g/L since 1966, while the south is considerably less saline, averaging 142 g/L since 1966. Ecological and industrial uses of the lake are dependent on long-term salinity remaining within physiological and economic thresholds, although optimal salinity varies for the ecosystem and between diverse stakeholders. In 2013, Union Pacific Railroad closed causeway culverts amid structural safety concerns and proposed to replace them with a bridge, offering four different bridge designs. As of summer 2015, no bridge design has been decided upon. We investigated the effect that each of the proposed bridge designs would have on north and south arm Great Salt Lake elevation and salinity by updating and applying US Geological Survey's Great Salt Lake Fortran Model. Overall, we found that salinity is sensitive to bridge size and depth, with larger designs increasing salinity in the south arm and decreasing salinity in the north arm. This research illustrates that flow modifications within terminal lakes cannot be separated from lake salinity, ecology, management, and economic uses.
Sun, Hongbing; Huffine, Maria; Husch, Jonathan; Sinpatanasakul, Leeann
2012-08-01
Using soil column experiments and data from natural watersheds, this paper analyzes the changes in Na/Cl molar ratios during a salting cycle of aqueous-soil systems. The soil column experiments involved introducing NaCl salt at various initial concentrations into multiple soil columns. At the start of a salting cycle in the column experiments, sodium was adsorbed more than chloride due to cation exchange processes. As a result, the initial Na/Cl molar ratio in column effluent was lower than 1, but increased thereafter. One-dimensional PHREEQC geochemical transport simulations also were conducted to further quantify these trends under more diverse scenarios. The experimentally determined Na/Cl molar ratio pattern was compared to observations in the annual salting cycle of four natural watersheds where NaCl is the dominant applied road deicing salt. Typically, Na/Cl molar ratios were low from mid-winter to early spring and increased after the bulk of the salt was flushed out of the watersheds during the summer, fall and early winter. The established relationship between the Na/Cl molar ratios and the amount of sodium retention derived from the column experiments and computer simulations present an alternative approach to the traditional budget analysis method for estimating sodium retention when the experimental and natural watershed patterns of Na/Cl molar ratio change are similar. Findings from this study enhance the understanding of sodium retention and help improve the scientific basis for future environmental policies intended to suppress the increase of sodium concentrations in salted watersheds. Copyright © 2012 Elsevier B.V. All rights reserved.
Model-Driven Safety Analysis of Closed-Loop Medical Systems
Pajic, Miroslav; Mangharam, Rahul; Sokolsky, Oleg; Arney, David; Goldman, Julian; Lee, Insup
2013-01-01
In modern hospitals, patients are treated using a wide array of medical devices that are increasingly interacting with each other over the network, thus offering a perfect example of a cyber-physical system. We study the safety of a medical device system for the physiologic closed-loop control of drug infusion. The main contribution of the paper is the verification approach for the safety properties of closed-loop medical device systems. We demonstrate, using a case study, that the approach can be applied to a system of clinical importance. Our method combines simulation-based analysis of a detailed model of the system that contains continuous patient dynamics with model checking of a more abstract timed automata model. We show that the relationship between the two models preserves the crucial aspect of the timing behavior that ensures the conservativeness of the safety analysis. We also describe system design that can provide open-loop safety under network failure. PMID:24177176
Model-Driven Safety Analysis of Closed-Loop Medical Systems.
Pajic, Miroslav; Mangharam, Rahul; Sokolsky, Oleg; Arney, David; Goldman, Julian; Lee, Insup
2012-10-26
In modern hospitals, patients are treated using a wide array of medical devices that are increasingly interacting with each other over the network, thus offering a perfect example of a cyber-physical system. We study the safety of a medical device system for the physiologic closed-loop control of drug infusion. The main contribution of the paper is the verification approach for the safety properties of closed-loop medical device systems. We demonstrate, using a case study, that the approach can be applied to a system of clinical importance. Our method combines simulation-based analysis of a detailed model of the system that contains continuous patient dynamics with model checking of a more abstract timed automata model. We show that the relationship between the two models preserves the crucial aspect of the timing behavior that ensures the conservativeness of the safety analysis. We also describe system design that can provide open-loop safety under network failure.
Unmixing Magnetic Hysteresis Loops
NASA Astrophysics Data System (ADS)
Heslop, D.; Roberts, A. P.
2012-04-01
Magnetic hysteresis loops provide important information in rock and environmental magnetic studies. Natural samples often contain an assemblage of magnetic particles composed of components with different origins. Each component potentially carries important environmental information. Hysteresis loops, however, provide information concerning the bulk magnetic assemblage, which makes it difficult to isolate the specific contributions from different sources. For complex mineral assemblages an unmixing strategy with which to separate hysteresis loops into their component parts is therefore essential. Previous methods to unmix hysteresis data have aimed at separating individual loops into their constituent parts using libraries of type-curves thought to correspond to specific mineral types. We demonstrate an alternative approach, which rather than decomposing a single loop into monomineralic contributions, examines a collection of loops to determine their constituent source materials. These source materials may themselves be mineral mixtures, but they provide a genetically meaningful decomposition of a magnetic assemblage in terms of the processes that controlled its formation. We show how an empirically derived hysteresis mixing space can be created, without resorting to type-curves, based on the co-variation within a collection of measured loops. Physically realistic end-members, which respect the expected behaviour and symmetries of hysteresis loops, can then be extracted from the mixing space. These end-members allow the measured loops to be described as a combination of invariant parts that are assumed to represent the different sources in the mixing model. Particular attention is paid to model selection and estimating the complexity of the mixing model, specifically, how many end-members should be included. We demonstrate application of this approach using lake sediments from Butte Valley, northern California. Our method successfully separates the hysteresis loops
Testing of a Neon Loop Heat Pipe for Large Area Cryocooling
NASA Technical Reports Server (NTRS)
Ku, Jentung; Robinson, Franklin Lee
2014-01-01
Cryocooling of large areas such as optics, detector arrays, and cryogenic propellant tanks is required for future NASA missions. A cryogenic loop heat pipe (CLHP) can provide a closed-loop cooling system for this purpose and has many advantages over other devices in terms of reduced mass, reduced vibration, high reliability, and long life. A neon CLHP was tested extensively in a thermal vacuum chamber using a cryopump as the heat sink to characterize its transient and steady performance and verify its ability to cool large areas or components. Tests conducted included loop cool-down from the ambient temperature, startup, power cycle, heat removal capability, loop capillary limit and recovery from a dry-out, low power operation, and long duration steady state operation. The neon CLHP demonstrated robust operation. The loop could be cooled from the ambient temperature to subcritical temperatures very effectively, and could start successfully by applying power to both the pump and evaporator without any pre-conditioning. It could adapt to changes in the pump power andor evaporator power, and reach a new steady state very quickly. The evaporator could remove heat loads between 0.25W and 4W. When the pump capillary limit was exceeded, the loop could resume its normal function by reducing the pump power. Steady state operations were demonstrated for up to 6 hours. The ability of the neon loop to cool large areas was therefore successfully verified.
Closed-loop pulsed helium ionization detector
Ramsey, Roswitha S.; Todd, Richard A.
1987-01-01
A helium ionization detector for gas chromatography is operated in a constant current, pulse-modulated mode by configuring the detector, electrometer and a high voltage pulser in a closed-loop control system. The detector current is maintained at a fixed level by varying the frequency of fixed-width, high-voltage bias pulses applied to the detector. An output signal proportional to the pulse frequency is produced which is indicative of the charge collected for a detected species.
Study of Fluid Cooling Loop System in Chinese Manned Spacecraft
NASA Astrophysics Data System (ADS)
Jiang, Jun; Xu, Jiwan; Fan, Hanlin; Huang, Jiarong
2002-01-01
change. To solve the questions, a fluid cooling loop system must be applied to Chinese manned spacecraft besides other conventional thermal control methods, such as thermal control coatings, multiplayer insulation blankets, heat pipes, electro-heating adjustment temperature devices, and so on. The paper will introduce the thermal design of inner and outer fluid loop including their constitution and fundamental, etc. The capability of heat transportation and the accuracy of control temperature for the fluid loop will be evaluated and analyzed. To insure the air temperature of sealed cabins within 21+/-4, the inlet liquid temperature of condensing heat exchanger needs to be controlled within 9+/-2. To insure this, the inlet liquid temperature of middle heat exchanger needs to be controlled within 8+/-1.8. The inlet temperature point is controlled by a subsidiary loop adjusting: when the computer receives feedbacks of the deviation and the variety rate of deviation from the controlled temperature point. It drives the temperature control valve to adjust the flow flux distribution between the main loop through radiator and the subsidiary loop which isn't through radiator to control the temperature of the mixed fluid within 8+/-1.8. The paper will also introduce thermal designs of key parts in the cooling loop, such as space radiators, heat exchangers and cooling plates. Thermal simulated tests on the ground and flight tests have been performed to verify correctness of thermal designs. rational and the loop system works order. It realizes the circulation of absorbing heat dissipation to the loop and transferring it to radiator then radiating it to space. (2) loop control system controls inlet temperature of middle heat exchanger within 8+/-1.8 under various thermal cases. Thermal design of the middle heat exchanger insures inlet temperature of condensing heat within 9+/-2. Thereby, the air temperature of sealed cabins is controlled within about 21+/-4 accurately. (3) The
NASA Astrophysics Data System (ADS)
Eun, Hee Chul; Yang, Hee Chul; Lee, Han Soo; Kim, In Tae
2009-12-01
Salt separation and recovery from the salt wastes generated from a pyrochemical process is necessary to minimize the high-level waste volumes and to stabilize a final waste form. In this study, the thermal behavior of the LiCl-KCl eutectic salts containing rare earth oxychlorides or oxides was investigated during a vacuum distillation and condensation process. LiCl was more easily vaporized than the other salts (KCl and LiCl-KCl eutectic salt). Vaporization characteristics of LiCl-KCl eutectic salts were similar to that of KCl. The temperature to obtain the vaporization flux (0.1 g min -1 cm -2) was decreased by much as 150 °C by a reduction of the ambient pressure from 5 Torr to 0.5 Torr. Condensation behavior of the salt vapors was different with the ambient pressure. Almost all of the salt vapors were condensed and were formed into salt lumps during a salt distillation at the ambient pressure of 0.5 Torr and they were collected in the condensed salt storage. However, fine salt particles were formed when the salt distillation was performed at 10 Torr and it is difficult for them to be recovered. Therefore, it is thought that a salt vacuum distillation and condensation should be performed to recover almost all of the vaporized salts at a pressure below 0.5 Torr.
Black holes in loop quantum gravity.
Perez, Alejandro
2017-12-01
This is a review of results on black hole physics in the context of loop quantum gravity. The key feature underlying these results is the discreteness of geometric quantities at the Planck scale predicted by this approach to quantum gravity. Quantum discreteness follows directly from the canonical quantization prescription when applied to the action of general relativity that is suitable for the coupling of gravity with gauge fields, and especially with fermions. Planckian discreteness and causal considerations provide the basic structure for the understanding of the thermal properties of black holes close to equilibrium. Discreteness also provides a fresh new look at more (at the moment) speculative issues, such as those concerning the fate of information in black hole evaporation. The hypothesis of discreteness leads, also, to interesting phenomenology with possible observational consequences. The theory of loop quantum gravity is a developing program; this review reports its achievements and open questions in a pedagogical manner, with an emphasis on quantum aspects of black hole physics.
NASA Astrophysics Data System (ADS)
Tanigawa, Hiroyasu; Katoh, Yutai; Kohyama, Akira
1995-08-01
Effects of applied stress on early stages of interstitial type Frank loop evolution were investigated by both numerical calculation and irradiation experiments. The final objective of this research is to propose a comprehensive model of complex stress effects on microstructural evolution under various conditions. In the experimental part of this work, the microstructural analysis revealed that the differences in resolved normal stress caused those in the nucleation rates of Frank loops on {111} crystallographic family planes, and that with increasing external applied stress the total nucleation rate of Frank loops was increased. A numerical calculation was carried out primarily to evaluate the validity of models of stress effects on nucleation processes of Frank loop evolution. The calculation stands on rate equuations which describe evolution of point defects, small points defect clusters and Frank loops. The rate equations of Frank loop evolution were formulated for {111} planes, considering effects of resolved normal stress to clustering processes of small point defects and growth processes of Frank loops, separately. The experimental results and the predictions from the numerical calculation qualitatively coincided well with each other.
Golebiowski, Jérôme; Antonczak, Serge; Fernandez-Carmona, Juan; Condom, Roger; Cabrol-Bass, Daniel
2004-12-01
Nanosecond molecular dynamics using the Ewald summation method have been performed to elucidate the structural and energetic role of the closing base pair in loop-loop RNA duplexes neutralized by Mg2+ counterions in aqueous phases. Mismatches GA, CU and Watson-Crick GC base pairs have been considered for closing the loop of an RNA in complementary interaction with HIV-1 TAR. The simulations reveal that the mismatch GA base, mediated by a water molecule, leads to a complex that presents the best compromise between flexibility and energetic contributions. The mismatch CU base pair, in spite of the presence of an inserted water molecule, is too short to achieve a tight interaction at the closing-loop junction and seems to force TAR to reorganize upon binding. An energetic analysis has allowed us to quantify the strength of the interactions of the closing and the loop-loop pairs throughout the simulations. Although the water-mediated GA closing base pair presents an interaction energy similar to that found on fully geometry-optimized structure, the water-mediated CU closing base pair energy interaction reaches less than half the optimal value.
Coupled dual loop absorption heat pump
Sarkisian, Paul H.; Reimann, Robert C.; Biermann, Wendell J.
1985-01-01
A coupled dual loop absorption system which utilizes two separate complete loops. Each individual loop operates at three temperatures and two pressures. This low temperature loop absorber and condenser are thermally coupled to the high temperature loop evaporator, and the high temperature loop condenser and absorber are thermally coupled to the low temperature generator.
A systematic technique for the sequential restoration of salt structures
NASA Astrophysics Data System (ADS)
Rowan, Mark G.
1993-12-01
A method is described for the sequential restoration of cross sections in areas of salt tectonics where deformation is confined to the salt and higher layers. The subsurface geometry evolves with time through the interaction of various processes: sedimentation, compaction, isostatic adjustment, thermal subsidence (if present), faulting, and salt withdrawal/ diapirism. The technique systematically calculates and removes the effects of each of these processes during specified time intervals defined by the interpreted horizons. It makes no assumptions about salt kinematics and generally results in the area of the salt layer changing through time. The method is described for restoration of extensional terranes, but it is also suitable for areas of contractional salt tectonics with only minor modifications. After converting an interpreted seismic profile to depth, the top layer is stripped off and the underlying section is decompacted according to standard porosity-depth functions. A deep baseline, unaffected by compaction or deformation, is used to restore any isostatic compensation or thermal subsidence. Isostasy is calculated according to the Airy model, and differential sedimentary loading across a section is shown to be approximately balanced by changes in salt thickness so that the load is evenly distributed. After these processes have been reversed, the resulting geometry and the seismic data are used to create the sea-floor template for structural restoration. Fault offsets are removed and the layers down to the top salt are restored to this template, while the base salt remains fixed. The resulting space between the restored top salt and the fixed base salt defines the restored salt geometry. In addition, the difference between the sea-floor template and a fixed sea level provides a measure of the change in water depth (ignoring eustatic changes in sea level). The technique is applied to an interpreted seismic profile from the eastern Green Canyon/Ewing Bank
A low jitter all - digital phase - locked loop in 180 nm CMOS technology
NASA Astrophysics Data System (ADS)
Shumkin, O. V.; Butuzov, V. A.; Normanov, D. D.; Ivanov, P. Yu
2016-02-01
An all-digital phase locked loop (ADPLL) was implemented in 180 nm CMOS technology. The proposed ADPLL uses a digitally controlled oscillator to achieve 3 ps resolution. The pure digital phase locked loop is attractive because it is less sensitive to noise and operating conditions than its analog counterpart. The proposed ADPLL can be easily applied to different process as a soft IP block, making it very suitable for system-on-chip applications.
The diversity of H3 loops determines the antigen-binding tendencies of antibody CDR loops.
Tsuchiya, Yuko; Mizuguchi, Kenji
2016-04-01
Of the complementarity-determining regions (CDRs) of antibodies, H3 loops, with varying amino acid sequences and loop lengths, adopt particularly diverse loop conformations. The diversity of H3 conformations produces an array of antigen recognition patterns involving all the CDRs, in which the residue positions actually in contact with the antigen vary considerably. Therefore, for a deeper understanding of antigen recognition, it is necessary to relate the sequence and structural properties of each residue position in each CDR loop to its ability to bind antigens. In this study, we proposed a new method for characterizing the structural features of the CDR loops and obtained the antigen-binding ability of each residue position in each CDR loop. This analysis led to a simple set of rules for identifying probable antigen-binding residues. We also found that the diversity of H3 loop lengths and conformations affects the antigen-binding tendencies of all the CDR loops. © 2016 The Protein Society.
1946-08-01
porfoot roflootor in tbo ti/k band ....<> nt It is found gonaidoroily oaaior vhon dealing v-ith problem involving tho pick -up of loop ooricla to...froqtionoloa to ’tho axtroooa and noon of tho froqiionoy bond in oporational uso for aircraft. Tho lattor froquonoy \\ ms adopted for tho purpoao of...wave horizontal loop oscillator at 13*6 Ha/a, and,’ since the structure is broad, the resonance peak will be correspondingly wide and may reasonably
One-loop Pfaffians and large-field inflation in string theory
NASA Astrophysics Data System (ADS)
Ruehle, Fabian; Wieck, Clemens
2017-06-01
We study the consistency of large-field inflation in low-energy effective field theories of string theory. In particular, we focus on the stability of Kähler moduli in the particularly interesting case where the non-perturbative superpotential of the Kähler sector explicitly depends on the inflaton field. This situation arises generically due to one-loop corrections to the instanton action. The field dependence of the modulus potential feeds back into the inflationary dynamics, potentially impairing slow roll. We distinguish between world-sheet instantons from Euclidean D-branes, which typically yield polynomial one-loop Pfaffians, and gaugino condensates, which can yield exponential or periodic corrections. In all scenarios successful slow-roll inflation imposes bounds on the magnitude of the one-loop correction, corresponding to constraints on possible compactifications. While we put a certain emphasis on Type IIB constructions with mobile D7-branes, our results seem to apply more generally.
An application of LOTEM around salt dome near Houston, Texas
NASA Astrophysics Data System (ADS)
Paembonan, Andri Yadi; Arjwech, Rungroj; Davydycheva, Sofia; Smirnov, Maxim; Strack, Kurt M.
2017-07-01
A salt dome is an important large geologic structure for hydrocarbon exploration. It may seal a porous reservoir of rocks that form petroleum reservoirs. Several techniques such as seismic, gravity, and electromagnetic including magnetotelluric have successfully yielded salt dome interpretation. Seismic has difficulties seeing through the salt because the seismic energy gets trapped by the salt due to its high velocity. Gravity and electromagnetics are more ideal methods. Long Offset Transient Electromagnetic (LOTEM) and Focused Source Electromagnetic (FSEM) were tested over a salt dome near Houston, Texas. LOTEM data were recorded at several stations with varying offset, and the FSEM tests were also made at some receiver locations near a suspected salt overhang. The data were processed using KMS's processing software: First, for assurance, including calibration and header checking; then transmitter and receiver data are merged and microseismic data is separated; Finally, data analysis and processing follows. LOTEM processing leads to inversion or in the FSEM case 3D modeling. Various 3D models verify the sensitivity under the salt dome. In addition, the processing was conducted pre-stack, stack, and post-stack. After pre-stacking, the noise was reduced, but showed the ringing effect due to a low-pass filter. Stacking and post-stacking with applying recursive average could reduce the Gibbs effect and produce smooth data.
How Do Changes to the Railroad Causeway in Utah’s Great Salt Lake Affect Water and Salt Flow?
White, James S.; Null, Sarah E.; Tarboton, David G.
2015-01-01
Managing terminal lake elevation and salinity are emerging problems worldwide. We contribute to terminal lake management research by quantitatively assessing water and salt flow for Utah’s Great Salt Lake. In 1959, Union Pacific Railroad constructed a rock-filled causeway across the Great Salt Lake, separating the lake into a north and south arm. Flow between the two arms was limited to two 4.6 meter wide rectangular culverts installed during construction, an 88 meter opening (referred to locally as a breach) installed in 1984, and the semi porous material of the causeway. A salinity gradient developed between the two arms of the lake over time because the south arm receives approximately 95% of the incoming streamflow entering Great Salt Lake. The north arm is often at, or near, salinity saturation, averaging 317 g/L since 1966, while the south is considerably less saline, averaging 142 g/L since 1966. Ecological and industrial uses of the lake are dependent on long-term salinity remaining within physiological and economic thresholds, although optimal salinity varies for the ecosystem and between diverse stakeholders. In 2013, Union Pacific Railroad closed causeway culverts amid structural safety concerns and proposed to replace them with a bridge, offering four different bridge designs. As of summer 2015, no bridge design has been decided upon. We investigated the effect that each of the proposed bridge designs would have on north and south arm Great Salt Lake elevation and salinity by updating and applying US Geological Survey’s Great Salt Lake Fortran Model. Overall, we found that salinity is sensitive to bridge size and depth, with larger designs increasing salinity in the south arm and decreasing salinity in the north arm. This research illustrates that flow modifications within terminal lakes cannot be separated from lake salinity, ecology, management, and economic uses. PMID:26641101
Thermal Management of a Nitrogen Cryogenic Loop Heat Pipe
NASA Astrophysics Data System (ADS)
Gully, Ph.; Yan, T.
2010-04-01
Efficient thermal links are needed to ease the distribution of the cold power in satellites. Loop heat pipes are widely used at room temperature as passive thermal links based on a two-phase flow generated by capillary forces. Transportation of the cold power at cryogenic temperatures requires a specific design. In addition to the main loop, the cryogenic loop heat pipe (CLHP) features a hot reservoir and a secondary loop with a cold reservoir and a secondary evaporator which allows the cool down and the thermal management of the thermal link in normal cold operation. We have studied the influence of a heated cold reservoir and investigated the effect of parasitic heat loads on the performance of a nitrogen CLHP at around 80 K. It is shown that heating of the cold reservoir with a small amount of power (0.1 W) allows controlling the system temperature difference, which can be kept constant at a very low level (1 K) regardless of the transferred cold power (0-10 W). Parasitic heat loads have a significant effect on the thermal resistance, and the power applied on the secondary evaporator has to be increased up to 4 W to get stable operation.
Molten Salt Promoting Effect in Double Salt CO2 Absorbents
DOE Office of Scientific and Technical Information (OSTI.GOV)
Zhang, Keling; Li, Xiaohong S.; Chen, Haobo
2016-01-01
The purpose of this paper is to elaborate on the concept of molten salts as catalysts for CO2 absorption by MgO, and extend these observations to the MgO-containing double salt oxides. We will show that the phenomena involved with CO2 absorption by MgO and MgO-based double salts are similar and general, but with some important differences. This paper focuses on the following key concepts: i) identification of conditions that favor or disfavor participation of isolated MgO during double salt absorption, and investigation of methods to increase the absorption capacity of double salt systems by including MgO participation; ii) examination ofmore » the relationship between CO2 uptake and melting point of the promoter salt, leading to the recognition of the role of pre-melting (surface melting) in these systems; and iii) extension of the reaction pathway model developed for the MgO-NaNO3 system to the double salt systems. This information advances our understanding of MgO-based CO2 absorption systems for application with pre-combustion gas streams.« less
Numerical simulations of loops heated to solar flare temperatures. III - Asymmetrical heating
NASA Technical Reports Server (NTRS)
Cheng, C.-C.; Doschek, G. A.; Karpen, J. T.
1984-01-01
A numerical model is defined for asymmetric full solar flare loop heating and comparisons are made with observational data. The Dynamic Flux Tube Model is used to describe the heating process in terms of one-dimensional, two fluid conservation equations of mass, energy and momentum. An adaptive grid allows for the downward movement of the transition region caused by an advancing conduction front. A loop 20,000 km long is considered, along with a flare heating system and the hydrodynamic evolution of the loop. The model was applied to generating line profiles and spatial X-ray and UV line distributions, which were compared with SMM, P78-1 and Hintori data for Fe, Ca and Mg spectra. Little agreement was obtained, and it is suggested that flares be treated as multi-loop phenomena. Finally, it is concluded that chromospheric evaporation is not an effective mechanism for generating the soft X-ray bursts associated with flares.
Resection with laser and high frequency cutting loop in tracheo-bronchial diseases.
Illum, P
1989-04-01
A total of 23 patients have been treated endoscopically during the last three and a half years for a variety of diseases in the tracheo-bronchial tree; nine had a tracheal stenosis. Thirteen patients have been treated by resection with a high frequency cutting loop, eleven with a CO2-laser and one with an argon laser. A total of 44 treatments have been performed. Half of the treatments were given because of various malignant diseases. The results of the treatment of this very mixed group of patients were, as a whole, satisfactory with both CO2-laser and cutting loop. A more precise technique can be applied with the CO2-laser than the cutting loop, though the latter is the more efficient and easy to work with. Care must be taken with the loop because of its greater cutting depth. The argon laser has only limited use in the treatment of diseases in the trachea.
Hard-thermal-loop perturbation theory to two loops
NASA Astrophysics Data System (ADS)
Andersen, Jens O.; Braaten, Eric; Petitgirard, Emmanuel; Strickland, Michael
2002-10-01
We calculate the pressure for pure-glue QCD at high temperature to two-loop order using hard-thermal-loop (HTL) perturbation theory. At this order, all the ultraviolet divergences can be absorbed into renormalizations of the vacuum energy density and the HTL mass parameter. We determine the HTL mass parameter by a variational prescription. The resulting predictions for the pressure fail to agree with results from lattice gauge theory at temperatures for which they are available.
NASA Astrophysics Data System (ADS)
Vilar, Jose M. G.; Saiz, Leonor
2006-06-01
DNA looping plays a fundamental role in a wide variety of biological processes, providing the backbone for long range interactions on DNA. Here we develop the first model for DNA looping by an arbitrarily large number of proteins and solve it analytically in the case of identical binding. We uncover a switchlike transition between looped and unlooped phases and identify the key parameters that control this transition. Our results establish the basis for the quantitative understanding of fundamental cellular processes like DNA recombination, gene silencing, and telomere maintenance.
Elaboration of garlic and salt spice with reduced sodium intake.
Rodrigues, Jéssica F; Junqueira, Gabriela; Gonçalves, Carla S; Carneiro, João D S; Pinheiro, Ana Carla M; Nunes, Cleiton A
2014-12-01
Garlic and salt spice is widely used in Brazilian cookery, but it has a high sodium content; as high sodium intake has been strongly correlated to the incidence of chronic diseases. This study aimed to develop a garlic and salt spice with reduced sodium intake. Sensory evaluation was conducted by applying the spices to cooked rice. First, the optimal concentration of spice added during rice preparation was determined. Subsequently, seasonings (3:1) were prepared containing 0%, 50% and 25% less NaCl using a mixture of salts consisting of KCl and monosodium glutamate; a seasoning with a 0% NaCl reduction was established as a control. Three formulations of rice with different spices were assessed according to sensory testing acceptance, time-intensity and temporal domain of sensations. The proportions of salts used in the garlic and salt spice did not generate a strange or bad taste in the products; instead, the mixtures were less salty. However, the seasonings with lower sodium levels (F2 and F3) were better accepted in comparison to the traditional seasoning (F1). Therefore, a mixture of NaCl, KCl and monosodium glutamate is a viable alternative to develop a garlic and salt spice with reduced sodium intake.
Zhang, Xuena; Wu, Anshi; Yao, Shanglong; Xue, Zhanggang; Yue, Yun
2015-01-01
Background The CONCERT-CL closed-loop infusion system designed by VERYARK Technology Co., Ltd. (Guangxi, China) is an innovation using TCI combined with closed-loop controlled intravenous anesthesia under the guide of BIS. In this study we performed a randomized, controlled, multicenter study to compare closed-loop control and open-loop control of propofol by using the CONCERT-CL closed-loop infusion system. Methods 180 surgical patients from three medical centers undergone TCI intravenous anesthesia with propofol and remifentanil were randomly assigned to propofol closed-loop group and propofol opened-loop groups. Primary outcome was global score (GS, GS = (MDAPE+Wobble)/% of time of bispectral index (BIS) 40-60). Secondary outcomes were doses of the anesthetics and emergence time from anesthesia, such as, time to tracheal extubation. Results There were 89 and 86 patients in the closed-loop and opened-loop groups, respectively. GS in the closed-loop groups (22.21±8.50) were lower than that in the opened-loop group (27.19±15.26) (p=0.009). The higher proportion of time of BIS between 40 and 60 was also observed in the closed-loop group (84.11±9.50%), while that was 79.92±13.17% in the opened-loop group, (p=0.016). No significant differences in propofol dose and time of tracheal extubation were observed. The frequency of propofol regulation in the closed-loop group (31.55±9.46 times/hr) was obverse higher than that in the opened-loop group (6.84±6.21 times/hr) (p=0.000). Conclusion The CONCERT-CL closed-loop infusion system can automatically regulate the TCI of propofol, maintain the BIS value in an adequate range and reduce the workload of anesthesiologists better than open-loop system. Trial Registration ChiCTR ChiCTR-OOR-14005551 PMID:25886041
Loop-loop interactions govern multiple steps in indole-3-glycerol phosphate synthase catalysis
Zaccardi, Margot J; O'Rourke, Kathleen F; Yezdimer, Eric M; Loggia, Laura J; Woldt, Svenja; Boehr, David D
2014-01-01
Substrate binding, product release, and likely chemical catalysis in the tryptophan biosynthetic enzyme indole-3-glycerol phosphate synthase (IGPS) are dependent on the structural dynamics of the β1α1 active-site loop. Statistical coupling analysis and molecular dynamic simulations had previously indicated that covarying residues in the β1α1 and β2α2 loops, corresponding to Arg54 and Asn90, respectively, in the Sulfolobus sulfataricus enzyme (ssIGPS), are likely important for coordinating functional motions of these loops. To test this hypothesis, we characterized site mutants at these positions for changes in catalytic function, protein stability and structural dynamics for the thermophilic ssIGPS enzyme. Although there were only modest changes in the overall steady-state kinetic parameters, solvent viscosity and solvent deuterium kinetic isotope effects indicated that these amino acid substitutions change the identity of the rate-determining step across multiple temperatures. Surprisingly, the N90A substitution had a dramatic effect on the general acid/base catalysis of the dehydration step, as indicated by the loss of the descending limb in the pH rate profile, which we had previously assigned to Lys53 on the β1α1 loop. These changes in enzyme function are accompanied with a quenching of ps-ns and µs-ms timescale motions in the β1α1 loop as measured by nuclear magnetic resonance studies. Altogether, our studies provide structural, dynamic and functional rationales for the coevolution of residues on the β1α1 and β2α2 loops, and highlight the multiple roles that the β1α1 loop plays in IGPS catalysis. Thus, substitution of covarying residues in the active-site β1α1 and β2α2 loops of indole-3-glycerol phosphate synthase results in functional, structural, and dynamic changes, highlighting the multiple roles that the β1α1 loop plays in enzyme catalysis and the importance of regulating the structural dynamics of this loop through noncovalent
Comparison of the CO2 laser and Leep-Loop method in treatment of changes in uterine cervix
NASA Astrophysics Data System (ADS)
Wozniak, Jakub; Wilczak, Maciej; Sajdak, Stefan; Opala, Tomasz; Rabiega, Dorota
2000-11-01
Electric leep-loop and lasersurgery are modern methods in treatment of diseases of uterine cervix that we can use often exchangeable. Differences first of all relates indications. Lasersurgery we can apply in diseases of uterine cervix channel. Application of electric leep in dysplasia of small grade of uterus cervix channel is possible. Before lasersurgery we should exclude cervical carcinoma, because we don't have histopathological material. Leep-loop conisation we shouldn't apply at young women, who plan pregnancy (risk of cicatristaion and dystokia of uterine cervix.)
Improvement in thrust force estimation of solenoid valve considering minor hysteresis loop
NASA Astrophysics Data System (ADS)
Yoon, Myung-Hwan; Choi, Yun-Yong; Hong, Jung-Pyo
2017-05-01
Solenoid valve is a very important hydraulic actuator for an automatic transmission in terms of shift quality. The same form of pressure for the clutch and the input current are required for an ideal control. However, the gap between a pressure and a current can occur which brings a delay in a transmission and a decrease in quality. This problem is caused by hysteresis phenomenon. As the ascending or descending magnetic field is applied to the solenoid, different thrust forces are generated. This paper suggests the calculation method of the thrust force considering the hysteresis phenomenon and consequently the accurate force can be obtained. Such hysteresis occurs in ferromagnetic materials, however the hysteresis phenomenon includes a minor hysteresis loop which begins with an initial magnetization curve and is generated by DC biased field density. As the core of the solenoid is ferromagnetic material, an accurate thrust force is obtained by applying the minor hysteresis loop compared to the force calculated by considering only the initial magnetization curve. An analytical background and the detailed explanation of measuring the minor hysteresis loop are presented. Furthermore experimental results and finite element analysis results are compared for the verification.
Toward a Quantitative Comparison of Magnetic Field Extrapolations and Observed Coronal Loops
NASA Astrophysics Data System (ADS)
Warren, Harry P.; Crump, Nicholas A.; Ugarte-Urra, Ignacio; Sun, Xudong; Aschwanden, Markus J.; Wiegelmann, Thomas
2018-06-01
It is widely believed that loops observed in the solar atmosphere trace out magnetic field lines. However, the degree to which magnetic field extrapolations yield field lines that actually do follow loops has yet to be studied systematically. In this paper, we apply three different extrapolation techniques—a simple potential model, a nonlinear force-free (NLFF) model based on photospheric vector data, and an NLFF model based on forward fitting magnetic sources with vertical currents—to 15 active regions that span a wide range of magnetic conditions. We use a distance metric to assess how well each of these models is able to match field lines to the 12202 loops traced in coronal images. These distances are typically 1″–2″. We also compute the misalignment angle between each traced loop and the local magnetic field vector, and find values of 5°–12°. We find that the NLFF models generally outperform the potential extrapolation on these metrics, although the differences between the different extrapolations are relatively small. The methodology that we employ for this study suggests a number of ways that both the extrapolations and loop identification can be improved.
DOE Office of Scientific and Technical Information (OSTI.GOV)
Schuster, D.C.
1996-12-31
Salt tectonics in the northern Gulf of Mexico involves both vertical diapirism and lateral silling or flow of salt into wings and tablets (sheets). Combinations of these two modes of salt deformation, concurrent with sediment loading and salt evacuation, have produced complex structures in the coastal and offshore region of southeastern Louisiana, a prolific oil and gas province. Many large growth faults and salt domes in the study area root into intra-Tertiary salt welds that were formerly occupied by allochthonous salt tablets. Two end-member structural systems involving evacuation of former tabular salt are recognized: roho systems and stepped counter-regional systems.more » Both end-member systems share a similar multi-staged evolution, including (1) initial formation of a south-leaning salt dome or wall sourced from the Jurassic salt level; (2) progressive development into a semi-tabular allochthonous salt body; and (3) subsequent loading, evacuation, and displacement of the tabular salt into secondary domes. In both systems, it is not uncommon to find salt displaced as much as 16-24 km south of its autochthonous source, connected by a horizontal salt weld to an updip, deflated counter-regional feeder. Although both end-member structural systems may originate before loading of allochthonous salt having grossly similar geometry, their final structural configurations after loading and salt withdrawal are distinctly different. Roho systems are characterized by large-displacement, listric, south-dipping growth faults that sole into intra-Tertiary salt welds marked by high-amplitude reflections continuous with residual salt masses. Salt from the former salt tablets has been loaded and squeezed laterally and downdip. Stepped counter-regional systems, in contrast, comprise large salt domes and adjacent large-displacement, north-dipping growth faults that sole into intra-Tertiary salt welds before stepping down again farther north.« less
Fiber lasers with loop reflectors.
Urquhart, P
1989-09-01
The theory of homogeneously broadened four level fiber lasers, which use fiber loops as distributed reflective elements, is examined. Such cavities can be made entirely from rare earth doped fiber. The amplifying characteristics of doped fiber loops are examined. The threshold pump power and the loop reflectivity necessary to optimize the lasing output power from an oscillator formed from two loops in series are predicted.
New iodide-based molten salt systems for high temperature molten salt batteries
NASA Astrophysics Data System (ADS)
Fujiwara, Syozo; Kato, Fumio; Watanabe, Syouichiro; Inaba, Minoru; Tasaka, Akimasa
Novel multi-component molten salt systems containing iodides, LiF-LiBr-LiI, LiF-NaBr-LiI, and LiF-LiCl-LiBr-LiI, were investigated for use as electrolytes in high temperature molten salt batteries to improve the discharge rate-capability. The iodide-based molten salts showed higher ionic conductivity (∼3 S cm -1 at 500 °C) than conventional LiCl-KCl, and had low enough melting points (below 400 °C) that can be used in practical high temperature molten salt batteries. The iodide-based salts showed instability at temperatures higher than 280 °C in dried air. The decomposition mechanism of iodide-based molten salts was discussed, and it was found that elimination of oxygen from the environment is effective to stabilize the iodide-based molten salts at high temperatures.
Closed-loop, pilot/vehicle analysis of the approach and landing task
NASA Technical Reports Server (NTRS)
Schmidt, D. K.; Anderson, M. R.
1985-01-01
Optimal-control-theoretic modeling and frequency-domain analysis is the methodology proposed to evaluate analytically the handling qualities of higher-order manually controlled dynamic systems. Fundamental to the methodology is evaluating the interplay between pilot workload and closed-loop pilot/vehicle performance and stability robustness. The model-based metric for pilot workload is the required pilot phase compensation. Pilot/vehicle performance and loop stability is then evaluated using frequency-domain techniques. When these techniques were applied to the flight-test data for thirty-two highly-augmented fighter configurations, strong correlation was obtained between the analytical and experimental results.
Shang, Jer-Yu; Mei, Joseph S.; Slagle, Frank D.; Notestein, John E.
1984-01-01
The present invention is directed to a combustion apparatus in the configuration of a oblong annulus defining a closed loop. Particulate coal together with a sulfur sorbent such as sulfur or dolomite is introduced into the closed loop, ignited, and propelled at a high rate of speed around the loop. Flue gas is withdrawn from a location in the closed loop in close proximity to an area in the loop where centrifugal force imposed upon the larger particulate material maintains these particulates at a location spaced from the flue gas outlet. Only flue gas and smaller particulates resulting from the combustion and innerparticle grinding are discharged from the combustor. This structural arrangement provides increased combustion efficiency due to the essentially complete combustion of the coal particulates as well as increased sulfur absorption due to the innerparticle grinding of the sorbent which provides greater particle surface area.
Fares, Souha A; Habib, Joseph R; Engoren, Milo C; Badr, Kamal F; Habib, Robert H
2016-06-01
Blood pressure exhibits substantial short- and long-term variability (BPV). We assessed the hypothesis that the complexity of beat-to-beat BPV will be differentially altered in salt-sensitive hypertensive Dahl rats (SS) versus rats protected from salt-induced hypertension (SSBN13) maintained on high-salt versus low-salt diet. Beat-to-beat systolic and diastolic BP series from nine SS and six SSBN13 rats (http://www.physionet.org) were analyzed following 9 weeks on low salt and repeated after 2 weeks on high salt. BP complexity was quantified by detrended fluctuation analysis (DFA), short- and long-range scaling exponents (αS and αL), sample entropy (SampEn), and traditional standard deviation (SD) and coefficient of variation (CV(%)). Mean systolic and diastolic BP increased on high-salt diet (P < 0.01) particularly for SS rats. SD and CV(%) were similar across groups irrespective of diet. Salt-sensitive and -protected rats exhibited similar complexity indices on low-salt diet. On high salt, (1) SS rats showed increased scaling exponents or smoother, systolic (P = 0.007 [αL]) and diastolic (P = 0.008 [αL]) BP series; (2) salt-protected rats showed lower SampEn (less complex) systolic and diastolic BP (P = 0.046); and (3) compared to protected SSBN13 rats, SS showed higher αL for systolic (P = 0.01) and diastolic (P = 0.005) BP Hypertensive SS rats are more susceptible to high salt with a greater rise in mean BP and reduced complexity. Comparable mean pressures in sensitive and protective rats when on low-salt diet coupled with similar BPV dynamics suggest a protective role of low-salt intake in hypertensive rats. This effect likely reflects better coupling of biologic oscillators. © 2016 The Authors. Physiological Reports published by Wiley Periodicals, Inc. on behalf of the American Physiological Society and The Physiological Society.
NASA Technical Reports Server (NTRS)
Snell, E. H.; vanderWoerd, M. J.; Miller, M. D.; Deacon, A. M.
2004-01-01
We demonstrate the use of inbred imaging to locate crystals mounted in cryoloops and cryopreserved in a nitrogen gas stream at 100K. In the home laboratory crystals are clearly seen in the infrared images with light transmitting through the sample while irradiating the crystal from behind, and with illumination from a direction perpendicular to the direction of view. The crystals transmit and reflect infrared radiation differently from the surrounding mother liquor and loop. Because of differences in contrast between crystals and their surrounding mother liquor, it is possible to clearly identify the crystal position. In use at the synchrotron, with robotically mounted crystals the small depth of field of the lens required the recording of multiple images at different focal points. Image processing techniques were then used to produce a clear image of the crystal. The resulting infrared images and intensity profiles show that infrared imaging can be a powerful complement to visual imaging in locating crystals in cryocooled loops.
Electrolyte salts for power sources
DOE Office of Scientific and Technical Information (OSTI.GOV)
Doddapaneni, Narayan; Ingersoll, David
Electrolyte salts for power sources comprising salts of phenyl polysulfonic acids and phenyl polyphosphonic acids. The preferred salts are alkali and alkaline earth metal salts, most preferably lithium salts.
Determination of the solubility of inorganic salts by headspace gas chromatography.
Chai, X S; Zhu, J Y
2003-05-09
This work reports a novel method for determination of salt solubility using headspace gas chromatography. A very small amount of volatile compound (such as methanol) is added in the studied solution. Due to the molecular interaction in the solution, the vapor-liquid equilibrium (VLE) partitioning coefficient of the volatile species will change with different salt contents in the solution. Therefore, the concentration of volatile species in the vapor phase is proportional to the salt concentration in the liquid phase, which can be easily determined by headspace gas chromatography. Until the salt concentration in the solution is saturated, the concentration of volatile compound in the vapor phase will continue to increase further and a breakpoint will appear on the VLE curve. The solubility of the salts can be determined by the identification of the breakpoint. It was found that the measured solubility of sodium carbonate and sodium sulfate in aqueous solutions is slightly higher (about 6-7%) than those reported in the literature method. The present method can be easily applied to industrial solution systems.
Coronal loop seismology using damping of standing kink oscillations by mode coupling
NASA Astrophysics Data System (ADS)
Pascoe, D. J.; Goddard, C. R.; Nisticò, G.; Anfinogentov, S.; Nakariakov, V. M.
2016-05-01
Context. Kink oscillations of solar coronal loops are frequently observed to be strongly damped. The damping can be explained by mode coupling on the condition that loops have a finite inhomogeneous layer between the higher density core and lower density background. The damping rate depends on the loop density contrast ratio and inhomogeneous layer width. Aims: The theoretical description for mode coupling of kink waves has been extended to include the initial Gaussian damping regime in addition to the exponential asymptotic state. Observation of these damping regimes would provide information about the structuring of the coronal loop and so provide a seismological tool. Methods: We consider three examples of standing kink oscillations observed by the Atmospheric Imaging Assembly (AIA) of the Solar Dynamics Observatory (SDO) for which the general damping profile (Gaussian and exponential regimes) can be fitted. Determining the Gaussian and exponential damping times allows us to perform seismological inversions for the loop density contrast ratio and the inhomogeneous layer width normalised to the loop radius. The layer width and loop minor radius are found separately by comparing the observed loop intensity profile with forward modelling based on our seismological results. Results: The seismological method which allows the density contrast ratio and inhomogeneous layer width to be simultaneously determined from the kink mode damping profile has been applied to observational data for the first time. This allows the internal and external Alfvén speeds to be calculated, and estimates for the magnetic field strength can be dramatically improved using the given plasma density. Conclusions: The kink mode damping rate can be used as a powerful diagnostic tool to determine the coronal loop density profile. This information can be used for further calculations such as the magnetic field strength or phase mixing rate.
NASA Technical Reports Server (NTRS)
Chen, George T.
1987-01-01
An automatic control scheme for spacecraft proximity operations is presented. The controller is capable of holding the vehicle at a prescribed location relative to a target, or maneuvering it to a different relative position using straight line-of-sight translations. The autopilot uses a feedforward loop to initiate and terminate maneuvers, and for operations at nonequilibrium set-points. A multivariate feedback loop facilitates precise position and velocity control in the presence of sensor noise. The feedback loop is formulated using the Linear Quadratic Gaussian (LQG) with Loop Transfer Recovery (LTR) design procedure. Linear models of spacecraft dynamics, adapted from Clohessey-Wiltshire Equations, are augmented and loop shaping techniques are applied to design a target feedback loop. The loop transfer recovery procedure is used to recover the frequency domain properties of the target feedback loop. The resulting compensator is integrated into an autopilot which is tested in a high fidelity Space Shuttle Simulator. The autopilot performance is evaluated for a variety of proximity operations tasks envisioned for future Shuttle flights.
A New Method for Setting Calculation Sequence of Directional Relay Protection in Multi-Loop Networks
NASA Astrophysics Data System (ADS)
Haijun, Xiong; Qi, Zhang
2016-08-01
Workload of relay protection setting calculation in multi-loop networks may be reduced effectively by optimization setting calculation sequences. A new method of setting calculation sequences of directional distance relay protection in multi-loop networks based on minimum broken nodes cost vector (MBNCV) was proposed to solve the problem experienced in current methods. Existing methods based on minimum breakpoint set (MBPS) lead to more break edges when untying the loops in dependent relationships of relays leading to possibly more iterative calculation workloads in setting calculations. A model driven approach based on behavior trees (BT) was presented to improve adaptability of similar problems. After extending the BT model by adding real-time system characters, timed BT was derived and the dependency relationship in multi-loop networks was then modeled. The model was translated into communication sequence process (CSP) models and an optimization setting calculation sequence in multi-loop networks was finally calculated by tools. A 5-nodes multi-loop network was applied as an example to demonstrate effectiveness of the modeling and calculation method. Several examples were then calculated with results indicating the method effectively reduces the number of forced broken edges for protection setting calculation in multi-loop networks.
Enthalpy-Based Thermal Evolution of Loops: II. Improvements to the Model
NASA Technical Reports Server (NTRS)
Cargill, P. J.; Bradshaw, S. J.; Klimchuk, J. A.
2011-01-01
This paper further develops the zero-dimensional (0D) hydrodynamic coronal loop model "Enthalpy-based Thermal Evolution of Loops" (EBTEL) originally proposed by Klimchuk et al (2008), which studies the plasma response to evolving coronal heating. It has typically been applied to impulsive heating events. The basis of EBTEL is the modelling of mass exchange between the corona and transition region and chromosphere in response to heating variations, with the key parameter being the ratio of transition region to coronal radiation. We develop new models for this parameter that now include gravitational stratification and a physically motivated approach to radiative cooling. A number of examples are presented, including nanoflares in short and long loops, and a small flare. It is found that while the evolution of the loop temperature is rather insensitive to the details of the model, accurate tracking of the density requires the inclusion of our new features. In particular, we are able to now obtain highly over-dense loops in the late cooling phase and decreases to the coronal density arising due to stratification. The 0D results are compared to a 1D hydro code (Hydrad). The agreement is acceptable, with the exception of the flare case where some versions of Hydrad can give significantly lower densities. This is attributed to the method used to model the chromosphere in a flare. EBTEL is suitable for general use as a tool for (a) quick-look results of loop evolution in response to a given heating function and (b) situations where the modelling of hundreds or thousands of elemental loops is needed. A single run takes a few seconds on a contemporary laptop.
DOE Office of Scientific and Technical Information (OSTI.GOV)
Sabau, Adrian; Wright, Ian
Boiler tubes in steam power plants experience tube blockages due to exfoliation of oxide grown on the inner side of the tubes. In extreme cases, significant tube blockages can lead to forced power plant outages. It is thus desired to predict through modeling the amount of tube blockage in order to inform power plant operators of possible forced outages. SpalLoop solves for the stress-strain equations in an axisymmetric geometry, tracking the stress/strain evolution during boiler operation including outages for the entire boiler tube length. At each operational outage, i.e., temperature excursions down to room temperature, the amount of exfoliated areamore » for the entire tube loop is estimated the amount of tube blockage is predicted based assumed blockage geometry and site. The SpaLLoop code contains modules developed for oxide growth, stress analysis, tube loop geometry, blockage area by taking into account the following phenomena and features, (a) Plant operation schedule with periodic alternate full-load and partial-load regimes and shut-downs, i.e., temperature excursions from high-load to room temperature, (b) axisymmetric formulation for cylindrical tubes, (c) oxide growth in a temperature gradient with multiple oxide layers, (d) geometry of a boiler tube with a single tube loop or two tube loops, (e) temperature variation along the tube length based on hot gas temperature distribution outside the tube and inlet steam temperature, (f) non-uniform oxide growth along the tube length according to the local steam tube temperature, (g) exfoliated area module: at each operational outage considered, the amount of exfoliated area and exfoliated volume along the tube is estimated, (h) blockage module: at each operational outage considered, the exfoliated volume/mass for each tube loop is estimated from which the amount of tube blockage is predicted based on given blockage geometry (length, location, and geometry). The computer program is written in FORTRAN90. Its
Latent energy storage with salt and metal mixtures for solar dynamic applications
NASA Technical Reports Server (NTRS)
Crane, R. A.; Konstantinou, K. S.
1988-01-01
This paper examines three design alternatives for the development of a solar dynamic heat receiver as applied to power systems operating in low earth orbit. These include a base line design used for comparison in ongoing NASA studies, a system incorporating a salt energy storage system with the salt dispersed within a metal mesh and a hybrid system incorporating both a molten salt and molten metal for energy storage. Based on a typical low earth orbit condition, designs are developed and compared to determine the effect of resultant conductivity, heat capacity and heat of fusion on system size, weight, temperature gradients, cycle turbine inlet temperature and material utilization.
Bandwidth controller for phase-locked-loop
NASA Technical Reports Server (NTRS)
Brockman, Milton H. (Inventor)
1992-01-01
A phase locked loop utilizing digital techniques to control the closed loop bandwidth of the RF carrier phase locked loop in a receiver provides high sensitivity and a wide dynamic range for signal reception. After analog to digital conversion, a digital phase locked loop bandwidth controller provides phase error detection with automatic RF carrier closed loop tracking bandwidth control to accommodate several modes of transmission.
Traces on orbifolds: anomalies and one-loop amplitudes
NASA Astrophysics Data System (ADS)
Groot Nibbelink, Stefan
2003-07-01
In the recent literature one can find calculations of various one-loop amplitudes, like anomalies, tadpoles and vacuum energies, on specific types of orbifolds, like S1/Bbb Z2. This work aims to give a general description of such one-loop computations for a large class of orbifold models. In order to achieve a high degree of generality, we formulate these calculations as evaluations of traces of operators over orbifold Hilbert spaces. We find that in general the result is expressed as a sum of traces over hyper surfaces with local projections, and the derivatives perpendicular to these hyper surfaces are rescaled. These local projectors naturally takes into account possible non-periodic boundary conditions. As the examples T6/Bbb Z4 and T4/D4 illustrate, the methods can be applied to non-prime as well as non-abelian orbifolds.
Goffe, Louis; Wrieden, Wendy; Penn, Linda; Hillier-Brown, Frances; Lake, Amelia A.; Araujo-Soares, Vera; Summerbell, Carolyn; White, Martin; Adamson, Ashley J.
2016-01-01
Objectives To determine if the amount of salt delivered by standard salt shakers commonly used in English independent takeaways varies between those with five and 17 holes; and to determine if any differences are robust to variations in: the amount of salt in the shaker, the length of time spent shaking, and the person serving. Design Four laboratory experiments comparing the amount of salt delivered by shakers. Independent variables considered were: type of shaker used (five or 17 holes), amount of salt in the shaker before shaking commences (shaker full, half full or nearly empty), time spent shaking (3s, 5s or 10s), and individual serving. Setting Controlled, laboratory, conditions. Participants A quota-based convenience sample of 10 participants (five women) aged 18–59 years. Main Outcome Measures Amount of salt delivered by salt shakers. Results Across all trials, the 17 holed shaker delivered a mean (SD) of 7.86g (4.54) per trial, whilst the five holed shaker delivered 2.65g (1.22). The five holed shaker delivered a mean of 33.7% of the salt of the 17 holed shaker. There was a significant difference in salt delivered between the five and 17 holed salt shakers when time spent shaking, amount of salt in the shaker and participant were all kept constant (p<0.001). This difference was robust to variations in the starting weight of shakers, time spent shaking and participant shaking (ps = 0.001). Conclusions Five holed salt shakers have the potential to reduce the salt content of takeaway food, and particularly food from Fish & Chip shops, where these shakers are particularly used. Further research will be required to determine the effects of this intervention on customers’ salt intake with takeaway food and on total dietary salt intake. PMID:27668747
A Bayesian Approach to Period Searching in Solar Coronal Loops
NASA Astrophysics Data System (ADS)
Scherrer, Bryan; McKenzie, David
2017-03-01
We have applied a Bayesian generalized Lomb-Scargle period searching algorithm to movies of coronal loop images obtained with the Hinode X-ray Telescope (XRT) to search for evidence of periodicities that would indicate resonant heating of the loops. The algorithm makes as its only assumption that there is a single sinusoidal signal within each light curve of the data. Both the amplitudes and noise are taken as free parameters. It is argued that this procedure should be used alongside Fourier and wavelet analyses to more accurately extract periodic intensity modulations in coronal loops. The data analyzed are from XRT Observation Program #129C: “MHD Wave Heating (Thin Filters),” which occurred during 2006 November 13 and focused on active region 10293, which included coronal loops. The first data set spans approximately 10 min with an average cadence of 2 s, 2″ per pixel resolution, and used the Al-mesh analysis filter. The second data set spans approximately 4 min with a 3 s average cadence, 1″ per pixel resolution, and used the Al-poly analysis filter. The final data set spans approximately 22 min at a 6 s average cadence, and used the Al-poly analysis filter. In total, 55 periods of sinusoidal coronal loop oscillations between 5.5 and 59.6 s are discussed, supporting proposals in the literature that resonant absorption of magnetic waves is a viable mechanism for depositing energy in the corona.
A Bayesian Approach to Period Searching in Solar Coronal Loops
DOE Office of Scientific and Technical Information (OSTI.GOV)
Scherrer, Bryan; McKenzie, David
2017-03-01
We have applied a Bayesian generalized Lomb–Scargle period searching algorithm to movies of coronal loop images obtained with the Hinode X-ray Telescope (XRT) to search for evidence of periodicities that would indicate resonant heating of the loops. The algorithm makes as its only assumption that there is a single sinusoidal signal within each light curve of the data. Both the amplitudes and noise are taken as free parameters. It is argued that this procedure should be used alongside Fourier and wavelet analyses to more accurately extract periodic intensity modulations in coronal loops. The data analyzed are from XRT Observation Programmore » 129C: “MHD Wave Heating (Thin Filters),” which occurred during 2006 November 13 and focused on active region 10293, which included coronal loops. The first data set spans approximately 10 min with an average cadence of 2 s, 2″ per pixel resolution, and used the Al-mesh analysis filter. The second data set spans approximately 4 min with a 3 s average cadence, 1″ per pixel resolution, and used the Al-poly analysis filter. The final data set spans approximately 22 min at a 6 s average cadence, and used the Al-poly analysis filter. In total, 55 periods of sinusoidal coronal loop oscillations between 5.5 and 59.6 s are discussed, supporting proposals in the literature that resonant absorption of magnetic waves is a viable mechanism for depositing energy in the corona.« less
NASA Technical Reports Server (NTRS)
Klimchuk, James A.; Karpen, Judy T.; Patsourakos, Spiros
2008-01-01
One of the great mysteries of coronal physics that has come to light in the last few years is the discovery that warn (- 1 INK) coronal loops are much denser than expected for quasi-static equilibrium. Both the excess densities and relatively long lifetimes of the loops can be explained with bundles of unresolved strands that are heated impulsively to very high temperatures. Since neighboring strands are at different stages of cooling, the composite loop bundle is multi-thermal, with the distribution of temperatures depending on the details of the "nanoflare storm." Emission hotter than 2 MK is predicted, but it is not clear that such emission is always observed. We consider two possible explanations for the existence of over-dense warm loops without corresponding hot emission: (1) loops are bundles of nanoflare heated strands, but a significant fraction of the nanoflare energy takes the form of a nonthermal electron beam rather then direct plasma heating; (2) loops are bundles of strands that undergo thermal nonequilibrium that results when steady heating is sufficiently concentrated near the footpoints. We present numerical hydro simulations of both of these possibilities and explore the observational consequences, including the production of hard X-ray emission and absorption by cool material in the corona.
Fault Detection and Safety in Closed-Loop Artificial Pancreas Systems
2014-01-01
Continuous subcutaneous insulin infusion pumps and continuous glucose monitors enable individuals with type 1 diabetes to achieve tighter blood glucose control and are critical components in a closed-loop artificial pancreas. Insulin infusion sets can fail and continuous glucose monitor sensor signals can suffer from a variety of anomalies, including signal dropout and pressure-induced sensor attenuations. In addition to hardware-based failures, software and human-induced errors can cause safety-related problems. Techniques for fault detection, safety analyses, and remote monitoring techniques that have been applied in other industries and applications, such as chemical process plants and commercial aircraft, are discussed and placed in the context of a closed-loop artificial pancreas. PMID:25049365
Towards loop quantum gravity without the time gauge.
Cianfrani, Francesco; Montani, Giovanni
2009-03-06
The Hamiltonian formulation of the Holst action is reviewed and it provides a solution of second-class constraints corresponding to a generic local Lorentz frame. Within this scheme the form of rotation constraints can be reduced to a Gauss-like one by a proper generalization of Ashtekar-Barbero-Immirzi connections. This result emphasizes that the loop quantum gravity quantization procedure can be applied when the time-gauge condition does not stand.
RCD+: Fast loop modeling server.
López-Blanco, José Ramón; Canosa-Valls, Alejandro Jesús; Li, Yaohang; Chacón, Pablo
2016-07-08
Modeling loops is a critical and challenging step in protein modeling and prediction. We have developed a quick online service (http://rcd.chaconlab.org) for ab initio loop modeling combining a coarse-grained conformational search with a full-atom refinement. Our original Random Coordinate Descent (RCD) loop closure algorithm has been greatly improved to enrich the sampling distribution towards near-native conformations. These improvements include a new workflow optimization, MPI-parallelization and fast backbone angle sampling based on neighbor-dependent Ramachandran probability distributions. The server starts by efficiently searching the vast conformational space from only the loop sequence information and the environment atomic coordinates. The generated closed loop models are subsequently ranked using a fast distance-orientation dependent energy filter. Top ranked loops are refined with the Rosetta energy function to obtain accurate all-atom predictions that can be interactively inspected in an user-friendly web interface. Using standard benchmarks, the average root mean squared deviation (RMSD) is 0.8 and 1.4 Å for 8 and 12 residues loops, respectively, in the challenging modeling scenario in where the side chains of the loop environment are fully remodeled. These results are not only very competitive compared to those obtained with public state of the art methods, but also they are obtained ∼10-fold faster. © The Author(s) 2016. Published by Oxford University Press on behalf of Nucleic Acids Research.
A digital wireless system for closed-loop inhibition of nociceptive signals
NASA Astrophysics Data System (ADS)
Zuo, Chao; Yang, Xiaofei; Wang, Yang; Hagains, Christopher E.; Li, Ai-Ling; Peng, Yuan B.; Chiao, J.-C.
2012-10-01
Neurostimulation of the spinal cord or brain has been used to inhibit nociceptive signals in pain management applications. Nevertheless, most of the current neurostimulation models are based on open-loop system designs. There is a lack of closed-loop systems for neurostimulation in research with small freely-moving animals and in future clinical applications. Based on our previously developed analog wireless system for closed-loop neurostimulation, a digital wireless system with real-time feedback between recorder and stimulator modules has been developed to achieve multi-channel communication. The wireless system includes a wearable recording module, a wearable stimulation module and a transceiver connected to a computer for real-time and off-line data processing, display and storage. To validate our system, wide dynamic range neurons in the spinal cord dorsal horn have been recorded from anesthetized rats in response to graded mechanical stimuli (brush, pressure and pinch) applied in the hind paw. The identified nociceptive signals were used to automatically trigger electrical stimulation at the periaqueductal gray in real time to inhibit their own activities by the closed-loop design. Our digital wireless closed-loop system has provided a simplified and efficient method for further study of pain processing in freely-moving animals and potential clinical application in patients. Groups 1, 2 and 3 contributed equally to this project.
Stretchable Random Lasers with Tunable Coherent Loops.
Sun, Tzu-Min; Wang, Cih-Su; Liao, Chi-Shiun; Lin, Shih-Yao; Perumal, Packiyaraj; Chiang, Chia-Wei; Chen, Yang-Fang
2015-12-22
Stretchability represents a key feature for the emerging world of realistic applications in areas, including wearable gadgets, health monitors, and robotic skins. Many optical and electronic technologies that can respond to large strain deformations have been developed. Laser plays a very important role in our daily life since it was discovered, which is highly desirable for the development of stretchable devices. Herein, stretchable random lasers with tunable coherent loops are designed, fabricated, and demonstrated. To illustrate our working principle, the stretchable random laser is made possible by transferring unique ZnO nanobrushes on top of polydimethylsiloxane (PDMS) elastomer substrate. Apart from the traditional gain material of ZnO nanorods, ZnO nanobrushes were used as optical gain materials so they can serve as scattering centers and provide the Fabry-Perot cavity to enhance laser action. The stretchable PDMS substrate gives the degree of freedom to mechanically tune the coherent loops of the random laser action by changing the density of ZnO nanobrushes. It is found that the number of laser modes increases with increasing external strain applied on the PDMS substrate due to the enhanced possibility for the formation of coherent loops. The device can be stretched by up to 30% strain and subjected to more than 100 cycles without loss in laser action. The result shows a major advance for the further development of man-made smart stretchable devices.
Great Salt Lake and Bonneville Salt Flats, UT, USA
NASA Technical Reports Server (NTRS)
1992-01-01
This is a view of the Great Salt Lake and nearby Bonneville Salt Flats, UT, (41.0N, 112.5W). A railroad causeway divides the lake with a stark straight line changing the water level and chemistry of the lake as a result. Fresh water runoff enters from the south adding to the depth and reducing the salinity. The north half receives little frsh water and is more saline and shallow. The Bonnieville Salt Flats is the lakebed of a onetime larger lake.
Great Salt Lake and Bonneville Salt Flats, UT, USA
1992-04-02
This is a view of the Great Salt Lake and nearby Bonneville Salt Flats, UT, (41.0N, 112.5W). A railroad causeway divides the lake with a stark straight line changing the water level and chemistry of the lake as a result. Fresh water runoff enters from the south adding to the depth and reducing the salinity. The north half receives little frsh water and is more saline and shallow. The Bonnieville Salt Flats is the lakebed of a onetime larger lake.
Non-planar one-loop Parke-Taylor factors in the CHY approach for quadratic propagators
NASA Astrophysics Data System (ADS)
Ahmadiniaz, Naser; Gomez, Humberto; Lopez-Arcos, Cristhiam
2018-05-01
In this work we have studied the Kleiss-Kuijf relations for the recently introduced Parke-Taylor factors at one-loop in the CHY approach, that reproduce quadratic Feynman propagators. By doing this, we were able to identify the non-planar one-loop Parke-Taylor factors. In order to check that, in fact, these new factors can describe non-planar amplitudes, we applied them to the bi-adjoint Φ3 theory. As a byproduct, we found a new type of graphs that we called the non-planar CHY-graphs. These graphs encode all the information for the subleading order at one-loop, and there is not an equivalent of these in the Feynman formalism.
Fragmentation of cosmic-string loops
NASA Technical Reports Server (NTRS)
York, Thomas
1989-01-01
The fragmentation of cosmic string loops is discussed, and the results of a simulation of this process are presented. The simulation can evolve any of a large class of loops essentially exactly, including allowing fragments that collide to join together. Such reconnection enhances the production of small fragments, but not drastically. With or without reconnections, the fragmentation process produces a collection of nonself-intersecting loops whose typical length is on the order of the persistence length of the initial loop.
Ritz, E; Ritz, C
2004-12-17
Recently increasing evidence has been provided pointing to a close relation of salt consumption to hypertension as well as to target organ damage. It is interesting to note that the discussion concerning salt is unusually emotional. This may be explained, at least in part, by the fact that since ancient times salt had deep symbolic significance, as exemplified, mostly subconsciously, by many customs and expressions still in current use. In the past salt was essential to preserve food. The past importance of salt as a commodity can well be compared with that of oil today. These and further historical aspects of the role of salt are briefly dealt with in this article.
Anterior loop of the inferior alveolar nerve: Averages and prevalence based on CT scans.
Juan, Del Valle Lovato; Grageda, Edgar; Gómez Crespo, Salvador
2016-02-01
The treatment of edentulous patients by using a complete implant-supported fixed prosthetic with distal extension has been widely studied; success is mainly dependent upon the placement of the distal implants. The location of the inferior alveolar nerve determines implant placement, but the length, prevalence, and symmetry between the left and right side of the anterior loop of the alveolar nerve are unknown. The purpose of this clinical study was to measure the anterior loop of the inferior alveolar nerve, which determines the placement of distal implants, in a group of 55 Mexican participants. The study expected to ascertain the average length, prevalence, and symmetry between left and right side and any sex differences. To differentiate the inferior alveolar nerve path, a new technique was applied using Hounsfield unit (HU) thresholds. The null hypothesis was that no significant differences would be found between the left and right sides or between men and women for the anterior loop of the inferior alveolar nerve. Fifty-five computed tomography (CT) scans were made (Somatom Sensation 16; Siemens Healthcare) and were visualized with InVesalius software. Anterior loop measurements were made on 3-dimensional surfaces. To determine statistical differences between the left and right side and between the sexes, the t test was used. The interclass correlation coefficient test was also applied to verify the reliability of the measurements. Ninety percent of participants showed the anterior loop of the inferior alveolar nerve. The length of the anterior loop ranged between 0 and 6.68 mm, with a mean of 2.19 mm. No significant differences were found between the left and right sides or between men and women. The mean length for the anterior loop in the sample was 2.19 mm. As the anterior loop length shows a high degree of variability, these findings suggest that a CT scan for each patient is recommended in order to visualize a safety zone before placing implants close to
Effect of winds and waves on salt intrusion in the Pearl River estuary
NASA Astrophysics Data System (ADS)
Gong, Wenping; Lin, Zhongyuan; Chen, Yunzhen; Chen, Zhaoyun; Zhang, Heng
2018-02-01
Salt intrusion in the Pearl River estuary (PRE) is a dynamic process that is influenced by a range of factors and to date, few studies have examined the effects of winds and waves on salt intrusion in the PRE. We investigate these effects using the Coupled Ocean-Atmosphere-Wave-Sediment Transport (COAWST) modeling system applied to the PRE. After careful validation, the model is used for a series of diagnostic simulations. It is revealed that the local wind considerably strengthens the salt intrusion by lowering the water level in the eastern part of the estuary and increasing the bottom landward flow. The remote wind increases the water mixing on the continental shelf, elevates the water level on the shelf and in the PRE and pumps saltier shelf water into the estuary by Ekman transport. Enhancement of the salt intrusion is comparable between the remote and local winds. Waves decrease the salt intrusion by increasing the water mixing. Sensitivity analysis shows that the axial down-estuary wind, is most efficient in driving increases in salt intrusion via wind straining effect.
NASA Astrophysics Data System (ADS)
Ovidiu, Avram; Rusu, Emil; Maftei, Raluca-Mihaela; Ulmeanu, Antonio; Scutelnicu, Ioan; Filipciuc, Constantina; Tudor, Elena
2017-12-01
Electrometry is most frequently applied geophysical method to examine dynamical phenomena related to the massive salt presence due to resistivity contrasts between salt, salt breccia and geological covering formations. On the vertical resistivity sections obtained with VES devices these three compartments are clearly differentiates by high resistivity for the massive salt, very low for salt breccia and variable for geological covering formations. When the land surface is inclined, shallow formations are moving gravitationally on the salt back, producing a landslide. Landslide monitoring involves repeated periodically measurements of geoelectrical profiles into a grid covering the slippery surface, in the same conditions (climate, electrodes position, instrument and measurement parameters). The purpose of monitoring landslides in Slanic Prahova area, was to detect the changes in resistivity distribution profiles to superior part of subsoil measured in 2014 and 2015. Measurement grid include several representative cross sections in susceptibility to landslides point of view. The results are graphically represented by changing the distribution of topography and resistivity differences between the two sets of geophysical measurements.
The Origin of Salt-Encased Sediment Packages: Observations from the SE Precaspian Basin (Kazakhstan)
NASA Astrophysics Data System (ADS)
Fernandez, Naiara; Duffy, Oliver B.; Hudec, Michael R.; Jackson, Martin P. A.; Burg, George; Jackson, Christopher A.-L.; Dooley, Tim P.
2017-04-01
Intrasalt sediment packages containing siliciclastic sediments, carbonate sediments, or non-halite evaporites such as gypsum or anhydrite are common within most salt sequences. Intrasalt sediment packages may have been deposited before, during, or after salt deposition and be incorporated into the salt by various processes. Understanding the origin and evolution of intrasalt sediment packages may yield important insights into the tectonic and geodynamic history of the basin, and also into the understanding of salt tectonics. Despite the importance of intrasalt sediment packages, currently there is no systematic description of their possible origins and their distinguishing criteria. This work is divided in three parts. First, we outline the possible origins of intrasalt sediment packages, as well as criteria to determine if they originated as subsalt, suprasalt or intrasalt sequences. Second, we examine how sediment packages that originated on top of salt, such as minibasins, can be encased within salt. We propose four key processes by which salt can be expelled and emplaced above minibasins to encase them: a) salt expulsion from beneath a minibasin experiencing density-driven subsidence; b) salt expulsion from beneath adjacent subsiding minibasins; c) salt expulsion associated with lateral shortening; d) override of minibasins by a salt sheet sourced from elsewhere. Third, we present a case study from the SE Precaspian Basin, Kazakhstan, where, using a borehole-constrained 3D seismic reflection dataset, the proposed criteria are applied to an area with abundant, newly discovered sediment packages within salt.
Simulation and Analysis of Launch Teams (SALT)
NASA Technical Reports Server (NTRS)
2008-01-01
A SALT effort was initiated in late 2005 with seed funding from the Office of Safety and Mission Assurance Human Factors organization. Its objectives included demonstrating human behavior and performance modeling and simulation technologies for launch team analysis, training, and evaluation. The goal of the research is to improve future NASA operations and training. The project employed an iterative approach, with the first iteration focusing on the last 70 minutes of a nominal-case Space Shuttle countdown, the second iteration focusing on aborts and launch commit criteria violations, the third iteration focusing on Ares I-X communications, and the fourth iteration focusing on Ares I-X Firing Room configurations. SALT applied new commercial off-the-shelf technologies from industry and the Department of Defense in the spaceport domain.
Characteristics of tuneable optical filters using optical ring resonator with PCF resonance loop
NASA Astrophysics Data System (ADS)
Shalmashi, K.; Seraji, F. E.; Mersagh, M. R.
2012-05-01
A theoretical analysis of a tuneable optical filter is presented by proposing an optical ring resonator (ORR) using photonic crystal fiber (PCF) as the resonance loop. The influences of the characteristic parameters of the PCF on the filter response have been analyzed under steady-state condition of the ORR. It is shown that the tuneability of the filter is mainly achieved by changing the modulation frequency of the light signal applied to the resonator. The analyses have shown that the sharpness and the depth of the filter response are controlled by parameters such as amplitude modulation index of applied field, the coupling coefficient of the ORR, and hole-spacing and air-filling ratio of the PCF, respectively. When transmission coefficient of the loop approaches the coupling coefficient, the filter response enhances sharply with PCF parameters. The depth and the full-width at half-maximum (FWHM) of the response strongly depend on the number of field circulations in the resonator loop. With the proposed tuneability scheme for optical filter, we achieved an FWHM of ~1.55 nm. The obtained results may be utilized in designing optical add/drop filters used in WDM communication systems.
Suppressing Transients In Digital Phase-Locked Loops
NASA Technical Reports Server (NTRS)
Thomas, J. B.
1993-01-01
Loop of arbitrary order starts in steady-state lock. Method for initializing variables of digital phase-locked loop reduces or eliminates transients in phase and frequency typically occurring during acquisition of lock on signal or when changes made in values of loop-filter parameters called "loop constants". Enables direct acquisition by third-order loop without prior acquisition by second-order loop of greater bandwidth, and eliminates those perturbations in phase and frequency lock occurring when loop constants changed by arbitrarily large amounts.
The Learning-Paradigm Campus: From Single- to Double-Loop Learning
ERIC Educational Resources Information Center
Tagg, John
2010-01-01
Since the 1980s, advocates for change in higher education have called for double-loop learning. One of the main criticisms of the evaluation of colleges and universities was that they measured inputs rather than the outputs. Higher education now needs to apply the lessons of learning and change to campus leadership and organization.
Study of the Open Loop and Closed Loop Oscillator Techniques
DOE Office of Scientific and Technical Information (OSTI.GOV)
Imel, George R.; Baker, Benjamin; Riley, Tony
This report presents the progress and completion of a five-year study undertaken at Idaho State University of the measurement of very small worth reactivity samples comparing open and closed loop oscillator techniques.The study conclusively demonstrated the equivalency of the two techniques with regard to uncertainties in reactivity values, i.e., limited by reactor noise. As those results are thoroughly documented in recent publications, in this report we will concentrate on the support work that was necessary. For example, we describe in some detail the construction and calibration of a pilot rod for the closed loop system. We discuss the campaign tomore » measure the required reactor parameters necessary for inverse-kinetics. Finally, we briefly discuss the transfer of the open loop technique to other reactor systems.« less
Study of the open loop and closed loop oscillator techniques
DOE Office of Scientific and Technical Information (OSTI.GOV)
Baker, Benjamin; Riley, Tony; Langbehn, Adam
This paper presents some aspects of a five year study undertaken at Idaho State University of the measurement of very small worth reactivity samples comparing open and closed loop oscillator techniques. The study conclusively demonstrated the equivalency of the two techniques with regard to uncertainties in reactivity values, i.e., limited by reactor noise. As those results are thoroughly documented in recent publications, in this paper we will concentrate on the support work that was necessary. For example, we describe in some detail the construction and calibration of a pilot rod for the closed loop system. We discuss the campaign tomore » measure the required reactor parameters necessary for inverse-kinetics. Finally, we briefly discuss the transfer of the open loop technique to other reactor systems. (authors)« less
SENER molten salt tower technology. Ouarzazate NOOR III case
NASA Astrophysics Data System (ADS)
Relloso, Sergio; Gutiérrez, Yolanda
2017-06-01
NOOR III 150 MWe project is the evolution of Gemasolar (19.9 MWe) to large scale Molten Salt Tower plants. With more than 5 years of operational experience, Gemasolar lessons learned have been the starting point for the optimization of this technology, considered the leader of potential cost reduction in CSP. In addition, prototypes of plant key components (heliostat and receiver) were manufactured and thoroughly tested before project launch in order to prove the new engineering solutions adopted. The SENER proprietary technology of NOOR III will be applied in the next Molten Salt Tower plants that will follow in other countries, such as South Africa, Chile and Australia.
Closed-loop supply chain models with considering the environmental impact.
Mohajeri, Amir; Fallah, Mohammad
2014-01-01
Global warming and climate changes created by large scale emissions of greenhouse gases are a worldwide concern. Due to this, the issue of green supply chain management has received more attention in the last decade. In this study, a closed-loop logistic concept which serves the purposes of recycling, reuse, and recovery required in a green supply chain is applied to integrate the environmental issues into a traditional logistic system. Here, we formulate a comprehensive closed-loop model for the logistics planning considering profitability and ecological goals. In this way, we can achieve the ecological goal reducing the overall amount of CO2 emitted from journeys. Moreover, the profitability criterion can be supported in the cyclic network with the minimum costs and maximum service level. We apply three scenarios and develop problem formulations for each scenario corresponding to the specified regulations and investigate the effect of the regulation on the preferred transport mode and the emissions. To validate the models, some numerical experiments are worked out and a comparative analysis is investigated.
Closed-Loop Supply Chain Models with Considering the Environmental Impact
Fallah, Mohammad
2014-01-01
Global warming and climate changes created by large scale emissions of greenhouse gases are a worldwide concern. Due to this, the issue of green supply chain management has received more attention in the last decade. In this study, a closed-loop logistic concept which serves the purposes of recycling, reuse, and recovery required in a green supply chain is applied to integrate the environmental issues into a traditional logistic system. Here, we formulate a comprehensive closed-loop model for the logistics planning considering profitability and ecological goals. In this way, we can achieve the ecological goal reducing the overall amount of CO2 emitted from journeys. Moreover, the profitability criterion can be supported in the cyclic network with the minimum costs and maximum service level. We apply three scenarios and develop problem formulations for each scenario corresponding to the specified regulations and investigate the effect of the regulation on the preferred transport mode and the emissions. To validate the models, some numerical experiments are worked out and a comparative analysis is investigated. PMID:25309960
Water purification using organic salts
Currier, Robert P.
2004-11-23
Water purification using organic salts. Feed water is mixed with at least one organic salt at a temperature sufficiently low to form organic salt hydrate crystals and brine. The crystals are separated from the brine, rinsed, and melted to form an aqueous solution of organic salt. Some of the water is removed from the aqueous organic salt solution. The purified water is collected, and the remaining more concentrated aqueous organic salt solution is reused.
Increased water resistance of paper treated with amylose-fatty ammonium salt inclusion complexes
USDA-ARS?s Scientific Manuscript database
Amylose inclusion complexes were prepared from high amylose corn starch and the HCl salts of hexadecylamine and octadecylamine. Solutions of the complexes were applied to paper at concentrations of 2-4%. After the treated papers were dried, sodium hydroxide solution was applied to convert the adsorb...
Technology transfer of operator-in-the-loop simulation
NASA Technical Reports Server (NTRS)
Yae, K. H.; Lin, H. C.; Lin, T. C.; Frisch, H. P.
1994-01-01
The technology developed for operator-in-the-loop simulation in space teleoperation has been applied to Caterpillar's backhoe, wheel loader, and off-highway truck. On an SGI workstation, the simulation integrates computer modeling of kinematics and dynamics, real-time computational and visualization, and an interface with the operator through the operator's console. The console is interfaced with the workstation through an IBM-PC in which the operator's commands were digitized and sent through an RS-232 serial port. The simulation gave visual feedback adequate for the operator in the loop, with the camera's field of vision projected on a large screen in multiple view windows. The view control can emulate either stationary or moving cameras. This simulator created an innovative engineering design environment by integrating computer software and hardware with the human operator's interactions. The backhoe simulation has been adopted by Caterpillar in building a virtual reality tool for backhoe design.
A circular polarization converter based on in-linked loop antenna frequency selective surface
NASA Astrophysics Data System (ADS)
Wang, Shen-Yun; Liu, Wei; Geyi, Wen
2018-06-01
In this paper, we report the design, fabrication and measurement of a circular polarization converter based on an in-linked loop-antenna frequency selective surface. The building unit cell is the in-linked loop-antenna module, which consists of same front and back planar loop antennas in-linked by a pair of through-via holes passing through a sandwiched perforated metal ground plane. The proposed device can achieve transmission polarization conversions from right- or left-handed circularly polarized waves to left- or right-handed ones, respectively, or vice versa. Simulation and experimental results show that it has relative conversion ratio of near unity at resonant frequency and very low Joule insertion loss in the operating frequency band. The proposed circular polarization converter may be applied to wireless systems where circular polarization diversity is needed.
Loop Heat Pipe Startup Behaviors
NASA Technical Reports Server (NTRS)
Ku, Jentung
2014-01-01
A loop heat pipe must start successfully before it can commence its service. The start-up transient represents one of the most complex phenomena in the loop heat pipe operation. This paper discusses various aspects of loop heat pipe start-up behaviors. Topics include the four start-up scenarios, the initial fluid distribution between the evaporator and reservoir that determines the start-up scenario, factors that affect the fluid distribution between the evaporator and reservoir, difficulties encountered during the low power start-up, and methods to enhance the start-up success. Also addressed are the thermodynamic constraint between the evaporator and reservoir in the loop heat pipe operation, the superheat requirement for nucleate boiling, pressure spike and pressure surge during the start-up transient, and repeated cycles of loop start-up andshutdown under certain conditions.
NASA Astrophysics Data System (ADS)
Rueslåtten, H.; Hovland, M. T.
2010-12-01
One of the common characteristics of planets Earth and Mars is that both host water (H2O) and large accumulations of salt. Whereas Earth’s surface-environment can be regarded as ‘water-friendly’ and ‘salt hostile’, the reverse can be said for the surface of Mars. This is because liquid water is stable on Earth, and the atmosphere transports humidity around the globe, whereas on planet Mars, liquid water is unstable, rendering the atmosphere dry and, therefore, ‘salt-friendly’. The riddle as to how the salt accumulated in various locations on those two planets, is one of long-lasting and great debate. The salt accumulations on Earth are traditionally termed ‘evaporites’, meaning that they formed as a consequence of the evaporation of large masses of seawater. How the accumulations on Mars formed is much harder to explain, as an ocean only existed briefly. Although water molecules and OH-groups may exist in abundance in bound form (crystal water, adsorbed water, etc.), the only place where free water is expected to be stable on Mars is within underground faults, fractures, and crevices. Here it likely occurs as brine or in the form of ice. Based on these conditions, a key to understanding the accumulation of large deposits of salt on both planets is linked to how brines behave in the subsurface when pressurized and heated beyond their supercritical point. At depths greater than about 3 km (P>300 bars) water will no longer boil in a steam phase. Rather, it becomes supercritical and will attain the phase of supercritical water vapor (SCRIW) with a specific gravity of typically 0.3 g/cm3. An important characteristic of SCRIW is its inability to dissolve the common sea salts. The salt dissolved in the brines will therefore precipitate as solid particles when brines (seawater on the Earth) move into the supercritical P&T-domain (T>400°C, P>300 bars). Numerical modeling of a hydrothermal system in the Atlantis II Deep of the Red Sea indicates that a
Chemical Looping Technology: Oxygen Carrier Characteristics.
Luo, Siwei; Zeng, Liang; Fan, Liang-Shih
2015-01-01
Chemical looping processes are characterized as promising carbonaceous fuel conversion technologies with the advantages of manageable CO2 capture and high energy conversion efficiency. Depending on the chemical looping reaction products generated, chemical looping technologies generally can be grouped into two types: chemical looping full oxidation (CLFO) and chemical looping partial oxidation (CLPO). In CLFO, carbonaceous fuels are fully oxidized to CO2 and H2O, as typically represented by chemical looping combustion with electricity as the primary product. In CLPO, however, carbonaceous fuels are partially oxidized, as typically represented by chemical looping gasification with syngas or hydrogen as the primary product. Both CLFO and CLPO share similar operational features; however, the optimum process configurations and the specific oxygen carriers used between them can vary significantly. Progress in both CLFO and CLPO is reviewed and analyzed with specific focus on oxygen carrier developments that characterize these technologies.
Transverse Oscillations of Coronal Loops
NASA Astrophysics Data System (ADS)
Ruderman, Michael S.; Erdélyi, Robert
2009-12-01
On 14 July 1998 TRACE observed transverse oscillations of a coronal loop generated by an external disturbance most probably caused by a solar flare. These oscillations were interpreted as standing fast kink waves in a magnetic flux tube. Firstly, in this review we embark on the discussion of the theory of waves and oscillations in a homogeneous straight magnetic cylinder with the particular emphasis on fast kink waves. Next, we consider the effects of stratification, loop expansion, loop curvature, non-circular cross-section, loop shape and magnetic twist. An important property of observed transverse coronal loop oscillations is their fast damping. We briefly review the different mechanisms suggested for explaining the rapid damping phenomenon. After that we concentrate on damping due to resonant absorption. We describe the latest analytical results obtained with the use of thin transition layer approximation, and then compare these results with numerical findings obtained for arbitrary density variation inside the flux tube. Very often collective oscillations of an array of coronal magnetic loops are observed. It is natural to start studying this phenomenon from the system of two coronal loops. We describe very recent analytical and numerical results of studying collective oscillations of two parallel homogeneous coronal loops. The implication of the theoretical results for coronal seismology is briefly discussed. We describe the estimates of magnetic field magnitude obtained from the observed fundamental frequency of oscillations, and the estimates of the coronal scale height obtained using the simultaneous observations of the fundamental frequency and the frequency of the first overtone of kink oscillations. In the last part of the review we summarise the most outstanding and acute problems in the theory of the coronal loop transverse oscillations.
Salt Stability - The Effect of pHmax on Salt to Free Base Conversion.
Hsieh, Yi-Ling; Merritt, Jeremy M; Yu, Weili; Taylor, Lynne S
2015-09-01
The aim of this study was to investigate how the disproportionation process can be impacted by the properties of the salt, specifically pHmax. Five miconazole salts and four sertraline salts were selected for this study. The extent of conversion was quantified using Raman spectroscopy. A mathematical model was utilized to estimate the theoretical amount of conversion. A trend was observed that for a given series of salts of a particular basic compound (both sertraline and miconazole are bases), the extent of disproportionation increases as pHmax decreases. Miconazole phosphate monohydrate and sertraline mesylate, although exhibiting significantly different pHmax values (more than 2 units apart), underwent a similar extent of disproportionation, which may be attributed to the lower buffering capacity of sertraline salts. This work shows that the disproportionation tendency can be influenced by pHmax and buffering capacity and thus highlights the importance of selecting the appropriate salt form during the screening process in order to avoid salt-to-free form conversion.
The Structure of Coronal Loops
NASA Technical Reports Server (NTRS)
Antiochos, Spiro K.
2009-01-01
It is widely believed that the simple coronal loops observed by XUV imagers, such as EIT, TRACE, or XRT, actually have a complex internal structure consisting of many (perhaps hundreds) of unresolved, interwoven "strands". According to the nanoflare model, photospheric motions tangle the strands, causing them to reconnect and release the energy required to produce the observed loop plasma. Although the strands, themselves, are unresolved by present-generation imagers, there is compelling evidence for their existence and for the nanoflare model from analysis of loop intensities and temporal evolution. A problem with this scenario is that, although reconnection can eliminate some of the strand tangles, it cannot destroy helicity, which should eventually build up to observable scales. we consider, therefore, the injection and evolution of helicity by the nanoflare process and its implications for the observed structure of loops and the large-scale corona. we argue that helicity does survive and build up to observable levels, but on spatial and temporal scales larger than those of coronal loops. we discuss the implications of these results for coronal loops and the corona, in general .
NASA Astrophysics Data System (ADS)
Handhika, T.; Bustamam, A.; Ernastuti, Kerami, D.
2017-07-01
Multi-thread programming using OpenMP on the shared-memory architecture with hyperthreading technology allows the resource to be accessed by multiple processors simultaneously. Each processor can execute more than one thread for a certain period of time. However, its speedup depends on the ability of the processor to execute threads in limited quantities, especially the sequential algorithm which contains a nested loop. The number of the outer loop iterations is greater than the maximum number of threads that can be executed by a processor. The thread distribution technique that had been found previously only be applied by the high-level programmer. This paper generates a parallelization procedure for low-level programmer in dealing with 2-level nested loop problems with the maximum number of threads that can be executed by a processor is smaller than the number of the outer loop iterations. Data preprocessing which is related to the number of the outer loop and the inner loop iterations, the computational time required to execute each iteration and the maximum number of threads that can be executed by a processor are used as a strategy to determine which parallel region that will produce optimal speedup.
Fabrication techniques for superconducting readout loops
NASA Technical Reports Server (NTRS)
Payne, J. E.
1982-01-01
Procedures for the fabrication of superconducting readout loops out of niobium on glass substrates were developed. A computer program for an existing fabrication system was developed. Both positive and negative resist procedures for the production of the readout loops were investigated. Methods used to produce satisfactory loops are described and the various parameters affecting the performance of the loops are analyzed.
NASA Technical Reports Server (NTRS)
Thierry-Palmer, Myrtle; Tewolde, Teclemicael K.; Forte, Camille; Wang, Min; Bayorh, Mohamed A.; Emmett, Nerimiah L.; White, Jolanda; Griffin, Keri
2002-01-01
Dahl salt-sensitive rats, but not salt-resistant rats, develop hypertension in response to high salt intake. We have previously shown an inverse relationship between plasma 25-hydroxyvitamin D (25-OHD) concentration and blood pressure of Dahl salt-sensitive rats during high salt intake. In this study, we report on the relationship between high salt intake and plasma 24,25-dihydroxyvitamin D (24,25-(OH)(2)D) concentration of Dahl salt-sensitive and salt-resistant rats. Rats were fed a high salt diet (8%) and sacrificed at day 2, 7, 14, 21, and 28. Plasma 24,25-(OH)(2)D concentrations of salt-sensitive rats were reduced to 50% of that at baseline at day 2-when blood pressure and plasma 25-OHD concentration were unchanged, but 25-OHD content in the kidney was 81% of that at baseline. Plasma 24,25-(OH)(2)D concentration was reduced further to 10% of that at baseline from day 7 to 14 of high salt intake, a reduction that was prevented in rats switched to a low salt (0.3%) diet at day 7. Exogenous 24,25-dihydroxycholecalciferol (24,25-(OH)(2)D(3)), administered at a level that increased plasma 24,25-(OH)(2)D concentration to five times normal, did not attenuate the salt-induced hypertension of salt-sensitive rats. Plasma 24,25-(OH)(2)D concentration of salt-resistant rats was gradually reduced to 50% of that at baseline at day 14 and returned to baseline value at day 28 of high salt intake. We conclude that the decrease in plasma 24,25-(OH)(2)D concentration in salt-sensitive rats during high salt intake is caused by decreased 25-OHD content in the kidney and also by another unidentified mechanism.
Maximized Gust Loads of a Closed-Loop, Nonlinear Aeroelastic System Using Nonlinear Systems Theory
NASA Technical Reports Server (NTRS)
Silva, Walter A.
1999-01-01
The problem of computing the maximized gust load for a nonlinear, closed-loop aeroelastic aircraft is discusses. The Volterra theory of nonlinear systems is applied in order to define a linearized system that provides a bounds on the response of the nonlinear system of interest. The method is applied to a simplified model of an Airbus A310.
Kadumuri, Rajashekar Varma; Vadrevu, Ramakrishna
2017-10-01
Due to their crucial role in function, folding, and stability, protein loops are being targeted for grafting/designing to create novel or alter existing functionality and improve stability and foldability. With a view to facilitate a thorough analysis and effectual search options for extracting and comparing loops for sequence and structural compatibility, we developed, LoopX a comprehensively compiled library of sequence and conformational features of ∼700,000 loops from protein structures. The database equipped with a graphical user interface is empowered with diverse query tools and search algorithms, with various rendering options to visualize the sequence- and structural-level information along with hydrogen bonding patterns, backbone φ, ψ dihedral angles of both the target and candidate loops. Two new features (i) conservation of the polar/nonpolar environment and (ii) conservation of sequence and conformation of specific residues within the loops have also been incorporated in the search and retrieval of compatible loops for a chosen target loop. Thus, the LoopX server not only serves as a database and visualization tool for sequence and structural analysis of protein loops but also aids in extracting and comparing candidate loops for a given target loop based on user-defined search options.
Park, Hwan-Seo; Kim, In-Tae; Cho, Yong-Zun; Eun, Hee-Chul; Lee, Han-Soo
2008-12-15
The molten salt waste from the pyroprocess is one of the problematic wastes to directly apply a conventional process such as vitrification or ceramization. This study suggested a novel method using a reactive material for metal chlorides at a molten temperature of salt waste, and then converting them into manageable product at a high temperature. The inorganic composite, SAP (SiO2-Al2O3-P2O5), synthesized by a conventional sol-gel process has three or four distinctive domains that are bonded sequentially, Si-O-Si-O-A-O-P-O-P. The P-rich phase in the SAP composite is unstable for producing a series of reactive sites when in contact with a molten LiCl salt. After the reaction, metal aluminosilicate, metal aluminophosphate, metal phosphates and gaseous chlorines are generated. From this process, the volatile salt waste is stabilized and it is possible to apply a high temperature process. The reaction products were fabricated successfully by using a borosilicate glass with an arbitrary composition as a chemical binder. There was a low possibility for the valorization of radionuclides up to 1200 degrees C, based on the result of the thermo gravimetric analysis. The Cs and Sr leach rates by the PCT-A method were about 1 x 10(-3) g/(m2 day). For the final disposal of the problematic salt waste, this approach suggested the design concept of an effective stabilizer for metal chlorides and revealed the chemical route to the fabrication of monolithic wasteform by using a composite as an example. Using this method, we could obtain a higher disposal efficiency and lower waste volume, compared with the present immobilization methods.
Coronal loops and active region structure
NASA Technical Reports Server (NTRS)
Webb, D. F.; Zirin, H.
1981-01-01
Synoptic H-alpha Ca K, magnetograph and Skylab soft X-ray and EUV data were compared for the purpose of identifying the basic coronal magnetic structure of loops in a 'typical' active region and studying its evolution. A complex of activity in July 1973, especially McMath 12417, was emphasized. The principal results are: (1) most of the brightest loops connected the bright f plage to either the sunspot penumbra or to p satellite spots; no non-flaring X-ray loops end in umbrae; (2) short, bright loops had one or both ends in regions of emergent flux, strong field or high field gradients; (3) stable, strongly sheared loop arcades formed over filaments; (4) EFRs were always associated with compact X-ray arcades; and (5) loops connecting to other active regions had their bases in outlying plage of weak field strength in McM 417 where H-alpha fibrils marked the direction of the loops
Comparison of salt taste thresholds and salt usage behaviours between adults in Myanmar and Korea.
Cho, Hyungjin; Kim, So Mi; Jeong, Seong Su; Kim, Soon Bae
2016-12-01
Excessive oral salt intake can induce hypertension. According to previous studies, the prevalence of hypertension is higher in Myanmar than in Korea. We postulated that Myanmar adults had higher salt taste thresholds and eat much saltier food. This study aimed to compare salt taste thresholds and salt usage behaviour scores between adults in Myanmar and Korea. This cross-sectional study enrolled patients who visited volunteer medical service clinics at Ansung in Korea and Hlegu and Bago in Myanmar in August 2014. We measured the vital signs, heights, and weights of each patient and evaluated detection thresholds, recognition thresholds, and salt preferences. All patients underwent urinalysis and spot urine Na tests. Additionally, they each completed a salt usage behaviour questionnaire. A total of 131 patients were enrolled, including 64 Myanmarese patients and 67 Korean patients. Blood pressure was significantly higher in the Myanmarese than in the Koreans. Detection and recognition thresholds, salt preferences, and spot urine sodium and salt usage behaviour scores were also higher in the Myanmarese than in the Korean subjects. We calculated correlation coefficients between systolic blood pressure and parameters that were related to salt intake. The detection and recognition thresholds were significantly correlated with systolic blood pressure. All parameters related to salt intake, including detection and recognition thresholds, salt preference, salt usage behaviour scores and spot urine sodium concentrations, are significantly higher in Myanmarese than in Korean individuals.
NASA Astrophysics Data System (ADS)
Pascoe, D. J.; Anfinogentov, S. A.; Goddard, C. R.; Nakariakov, V. M.
2018-06-01
The shape of the damping profile of kink oscillations in coronal loops has recently allowed the transverse density profile of the loop to be estimated. This requires accurate measurement of the damping profile that can distinguish the Gaussian and exponential damping regimes, otherwise there are more unknowns than observables. Forward modeling of the transverse intensity profile may also be used to estimate the width of the inhomogeneous layer of a loop, providing an independent estimate of one of these unknowns. We analyze an oscillating loop for which the seismological determination of the transverse structure is inconclusive except when supplemented by additional spatial information from the transverse intensity profile. Our temporal analysis describes the motion of a coronal loop as a kink oscillation damped by resonant absorption, and our spatial analysis is based on forward modeling the transverse EUV intensity profile of the loop under the isothermal and optically thin approximations. We use Bayesian analysis and Markov chain Monte Carlo sampling to apply our spatial and temporal models both individually and simultaneously to our data and compare the results with numerical simulations. Combining the two methods allows both the inhomogeneous layer width and density contrast to be calculated, which is not possible for the same data when each method is applied individually. We demonstrate that the assumption of an exponential damping profile leads to a significantly larger error in the inferred density contrast ratio compared with a Gaussian damping profile.
Mineral resource of the month: salt
Kostick, Dennis S.
2010-01-01
The article presents information on various types of salt. Rock salt is either found from underground halite deposits or near the surface. Other types of salt include solar salt, salt brine, and vacuum pan salt. The different uses of salt are also given including its use as a flavor enhancer, as a road deicing agent, and to manufacture sodium hydroxide.
Run-time parallelization and scheduling of loops
NASA Technical Reports Server (NTRS)
Saltz, Joel H.; Mirchandaney, Ravi; Crowley, Kay
1990-01-01
Run time methods are studied to automatically parallelize and schedule iterations of a do loop in certain cases, where compile-time information is inadequate. The methods presented involve execution time preprocessing of the loop. At compile-time, these methods set up the framework for performing a loop dependency analysis. At run time, wave fronts of concurrently executable loop iterations are identified. Using this wavefront information, loop iterations are reordered for increased parallelism. Symbolic transformation rules are used to produce: inspector procedures that perform execution time preprocessing and executors or transformed versions of source code loop structures. These transformed loop structures carry out the calculations planned in the inspector procedures. Performance results are presented from experiments conducted on the Encore Multimax. These results illustrate that run time reordering of loop indices can have a significant impact on performance. Furthermore, the overheads associated with this type of reordering are amortized when the loop is executed several times with the same dependency structure.
Coronal Loops: Observations and Modeling of Confined Plasma.
Reale, Fabio
Coronal loops are the building blocks of the X-ray bright solar corona. They owe their brightness to the dense confined plasma, and this review focuses on loops mostly as structures confining plasma. After a brief historical overview, the review is divided into two separate but not independent parts: the first illustrates the observational framework, the second reviews the theoretical knowledge. Quiescent loops and their confined plasma are considered and, therefore, topics such as loop oscillations and flaring loops (except for non-solar ones, which provide information on stellar loops) are not specifically addressed here. The observational section discusses the classification, populations, and the morphology of coronal loops, its relationship with the magnetic field, and the loop stranded structure. The section continues with the thermal properties and diagnostics of the loop plasma, according to the classification into hot, warm, and cool loops. Then, temporal analyses of loops and the observations of plasma dynamics, hot and cool flows, and waves are illustrated. In the modeling section, some basics of loop physics are provided, supplying fundamental scaling laws and timescales, a useful tool for consultation. The concept of loop modeling is introduced and models are divided into those treating loops as monolithic and static, and those resolving loops into thin and dynamic strands. More specific discussions address modeling the loop fine structure and the plasma flowing along the loops. Special attention is devoted to the question of loop heating, with separate discussion of wave (AC) and impulsive (DC) heating. Large-scale models including atmosphere boxes and the magnetic field are also discussed. Finally, a brief discussion about stellar coronal loops is followed by highlights and open questions.
NASA Astrophysics Data System (ADS)
Ings, Steven; Albertz, Markus
2014-05-01
Deformation of salt and sediments owing to the flow of weak evaporites is a common phenomenon in sedimentary basins worldwide, and the resulting structures and thermal regimes have a significant impact on hydrocarbon exploration. Evaporite sequences ('salt') of significant thickness (e.g., >1km) are typically deposited in many cycles of seawater inundation and evaporation in restricted basins resulting in layered autochthonous evaporite packages. However, analogue and numerical models of salt tectonics typically treat salt as a homogeneous viscous material, often with properties of halite, the weakest evaporite. In this study, we present results of two-dimensional plane-strain numerical experiments designed to illustrate the effects of variable evaporite viscosity and embedded frictional-plastic ('brittle') sediment layers on the style of salt flow and associated deformation of the sedimentary overburden. Evaporite viscosity is a first-order control on salt flow rate and the style of overburden deformation. Near-complete evacuation of low-viscosity salt occurs beneath expulsion basins, whereas significant salt is trapped when viscosity is high. Embedded frictional-plastic sediment layers (with finite yield strength) partition salt flow and develop transient contractional structures (folds, thrust faults, and folded faults) in a seaward salt-squeeze flow regime. Multiple internal sediment layers reduce the overall seaward salt flow during sediment aggradation, leaving more salt behind to be re-mobilized during subsequent progradation. This produces more seaward extensive allochthonous salt sheets. If there is a density difference between the embedded layers and the surrounding salt, then the embedded layers 'fractionate' during deformation and either float to the surface or sink to the bottom (depending on density), creating a thick zone of pure halite. Such a process of 'buoyancy fractionation' may partially explain the apparent paradox of layered salt in
Research on the Fatigue Flexural Performance of RC Beams Attacked by Salt Spray
NASA Astrophysics Data System (ADS)
Mao, Jiang-hong; Xu, Fang-yuan; Jin, Wei-liang; Zhang, Jun; Wu, Xi-xi; Chen, Cai-sheng
2018-04-01
The fatigue flexural performance of RC beams attacked by salt spray was studied. A testing method involving electro osmosis, electrical accelerated corrosion and salt spray was proposed. This corrosion process method effectively simulates real-world salt spray and fatigue loading exerted by RC components on sea bridges. Four RC beams that have different stress amplitudes were tested. It is found that deterioration by corrosion and fatigue loading reduces the fatigue life of the RC and decreases the ability of deformation. The fatigue life and deflection ability could be reduced by increasing the stress amplitude and the corrosion duration time. The test result demonstrates that this experimental method can couple corrosion deterioration and fatigue loading reasonably. This procedure may be applied to evaluate the fatigue life and concrete durability of RC components located in a natural salt spray environment.
Electrical double layers and differential capacitance in molten salts from density functional theory
Frischknecht, Amalie L.; Halligan, Deaglan O.; Parks, Michael L.
2014-08-05
Classical density functional theory (DFT) is used to calculate the structure of the electrical double layer and the differential capacitance of model molten salts. The DFT is shown to give good qualitative agreement with Monte Carlo simulations in the molten salt regime. The DFT is then applied to three common molten salts, KCl, LiCl, and LiKCl, modeled as charged hard spheres near a planar charged surface. The DFT predicts strong layering of the ions near the surface, with the oscillatory density profiles extending to larger distances for larger electrostatic interactions resulting from either lower temperature or lower dielectric constant. Inmore » conclusion, overall the differential capacitance is found to be bell-shaped, in agreement with recent theories and simulations for ionic liquids and molten salts, but contrary to the results of the classical Gouy-Chapman theory.« less
Temperature dependence of looping rates in a short peptide.
Roccatano, Danilo; Sahoo, Harekrushna; Zacharias, Martin; Nau, Werner M
2007-03-15
Knowledge of the influence of chain length and amino acid sequence on the structural and dynamic properties of small peptides in solution provides essential information on protein folding pathways. The combination of time-resolved optical spectroscopy and molecular dynamics (MD) simulation methods has become a powerful tool to investigate the kinetics of end-to-end collisions (looping rates) in short peptides, which are relevant in early protein folding events. We applied the combination of both techniques to study temperature-dependent (280-340 K) looping rates of the Dbo-AlaGlyGln-Trp-NH2 peptide, where Dbo represents a 2,3-diazabicyclo[2.2.2]oct-2-ene-labeled asparagine, which served as a fluorescent probe in the time-resolved spectroscopic experiments. The experimental looping rates increased from 4.8 x 10(7) s(-1) at 283 K to 2.0 x 10(8) s(-1) at 338 K in H2O. The corresponding Arrhenius plot provided as activation parameters Ea = 21.5 +/- 1.0 kJ mol(-1) and ln(A/s-1) = 26.8 +/- 0.2 in H2O. The results in D2O were consistent with a slight solvent viscosity effect, i.e., the looping rates were 10-20% slower. MD simulations were performed with the GROMOS96 force field in a water solvent model, which required first a parametrization of the synthetic amino acid Dbo. After corrections for solvent viscosity effects, the calculated looping rates varied from 1.5 x 10(8) s(-1) at 280 K to 8.2 x 10(8) s(-1) at 340 K in H2O, which was about four times larger than the experimental data. The calculated activation parameters were Ea = 24.7 +/- 1.5 kJ mol(-1) and ln(A/s(-1)) = 29.4 +/- 0.1 in H2O.
238Pu recovery and salt disposition from the molten salt oxidation process
NASA Astrophysics Data System (ADS)
Remerowski, M. L.; Stimmel, Jay J.; Wong, Amy S.; Ramsey, Kevin B.
2000-07-01
We have begun designing and optimizing our recovery and recycling processes by experimenting with samples of "spent salt" produced by MSO treatment of surrogate waste in the reaction vessel at the Naval Surface Warfare Center-Indian Head. One salt was produced by treating surrogate waste containing pyrolysis ash spiked with cerium. The other salt contains residues from MSO treatment of materials similar to those used in 238Pu processing, e.g., Tygon tubing, PVC bagout bags, HDPE bottles. Using these two salt samples, we will present results from our investigations.
NASA Astrophysics Data System (ADS)
Egartner, Isabel; Sass, Oliver
2016-04-01
The presented investigation is part of a longer-term project which deals with the influence of salt and moisture on weathering of historic stonework. The main investigation object in the field is a part of the 300 hundred year old boundary wall of the Worchester College in Oxford, UK. A range of non-destructive techniques were applied in course of field campaigns, e.g. mapping of weathering phenomena; handheld moisture sensors; and salt sampling by paper pulp poultices. In a second step we investigated the behaviour and distribution of water and salt solution in a porous material, similar to the limestone of the College wall, under laboratory condititions. Limestone cube samples (5x5x5 cm) were soaked first with ultrapure H2O and second with different concentration of saline solutions of NaCl and Na2SO4. During the dehydration process of the stone cubes a multi-method approach including sampling by drilling, paper pulp poultices, handheld moisture sensor, conductivity sensor and Ion Chromatography (IC) were applied to investigate the moisture and salt content and distribution within the samples. The laboratory analyses were carried out at the department of applied geoscience of the Technical University of Graz, Austria. The main aim was to investigate the effectivity of the paper pulp poultices in soaking up salts from the stone samples and to use the results of the laboratory analysis to interpret and calibrate the field work results from the College wall in Oxford. Keywords: Salt weathering, paper pulp poultices, cultural heritage, field work and laboratory investigation
On higher order discrete phase-locked loops.
NASA Technical Reports Server (NTRS)
Gill, G. S.; Gupta, S. C.
1972-01-01
An exact mathematical model is developed for a discrete loop of a general order particularly suitable for digital computation. The deterministic response of the loop to the phase step and the frequency step is investigated. The design of the digital filter for the second-order loop is considered. Use is made of the incremental phase plane to study the phase error behavior of the loop. The model of the noisy loop is derived and the optimization of the loop filter for minimum mean-square error is considered.
Dynamic Looping of a Free-Draining Polymer
DOE Office of Scientific and Technical Information (OSTI.GOV)
Ye, Felix X. -F.; Stinis, Panos; Qian, Hong
Here, we revisit the celebrated Wilemski--Fixman (WF) treatment for the looping time of a free-draining polymer. The WF theory introduces a sink term into the Fokker--Planck equation for themore » $3(N+1)$-dimensional Ornstein--Uhlenbeck process of polymer dynamics, which accounts for the appropriate boundary condition due to the formation of a loop. The assumption for WF theory is considerably relaxed. A perturbation method approach is developed that justifies and generalizes the previous results using either a delta sink or a Heaviside sink. For both types of sinks, we show that under the condition of a small dimensionless $$\\epsilon$$, the ratio of capture radius to the Kuhn length, we are able to systematically produce all known analytical and asymptotic results obtained by other methods. This includes most notably the transition regime between the $N^2$ scaling of Doi, and $$N\\sqrt{N}/\\epsilon$$ scaling of Szabo, Schulten, and Schulten. The mathematical issue at play is the nonuniform convergence of $$\\epsilon\\to 0$$ and $$N\\to\\infty$$, the latter being an inherent part of the theory of a Gaussian polymer. Our analysis yields a novel term in the analytical expression for the looping time with small $$\\epsilon$$, which was previously unknown. Monte Carlo numerical simulations corroborate the analytical findings. The systematic method developed here can be applied to other systems modeled by multidimensional Smoluchowski equations.« less
A cluster bootstrap for two-loop MHV amplitudes
Golden, John; Spradlin, Marcus
2015-02-02
We apply a bootstrap procedure to two-loop MHV amplitudes in planar N=4 super-Yang-Mills theory. We argue that the mathematically most complicated part (the Λ 2 B 2 coproduct component) of the n-particle amplitude is uniquely determined by a simple cluster algebra property together with a few physical constraints (dihedral symmetry, analytic structure, supersymmetry, and well-defined collinear limits). Finally, we present a concise, closed-form expression which manifests these properties for all n.
NASA Astrophysics Data System (ADS)
Jagoutz, E.
2006-12-01
Large well rounded boulders and angular rock fragments characterizes the Martian landscape as seen on the recent excellent quality photos. Analyzing the different rock-shapes indicates a time sequence of emplacement, fragmentation and transport of different rocks on Mars, which might give interesting insight into transport and weathering processes. Larger commonly well rounded boulders were emplaced onto gravel plains. After emplacement, these rocks were fragmented and disassembled. Nests of angular rock fragments are marking the locations of preexisting larger rocks. Frequently it is possible to reconstruct larger rounded rocks from smaller angular fragments. In other cases transport after fragmentation obscured the relationship of the fragments. However, a strewn field of fragments is still reminiscent of the preexisting rock. Mechanical salt weathering could be a plausible explanation for the insitu fragmentation of larger rounded blocks into angular fragments. Impact or secondary air fall induced fragmentation produces very different patterns, as observed around impact crates on Earth. Salt weathering of rocks is a common process in terrestrial environments. Salt crystallization in capillaries causes fragmentation of rocks, irrespective of the process of salt transportation and concentration. On Earth significant salt weathering can be observed in different climatic environments: in the transition zone of alluvial aprons and salt playas in desserts and in dry valleys of Antarctica. In terrestrial semi-arid areas the salt is transported by salt solution, which is progressively concentrated by evaporation. In Antarctic dry valleys freeze-thaw cycles causes salt transportation and crystallization resulting in rock fragmentation. This salt induced process can lead to complete destruction of rocks and converts rocks to fine sand. The efficient breakdown of rocks is dominating the landscape in some dry valleys of the Earth but possibly also on Mars. (Malin, 1974
Delahaye, François
2013-05-01
High blood pressure is a major cardiovascular risk factor. There is overwhelming evidence that high salt consumption is a major cause of increased blood pressure. There is also a link between high salt consumption and risk of stroke, left ventricular hypertrophy, renal disease, obesity, renal stones and stomach cancer. Reducing salt consumption leads to a decrease in blood pressure and the incidence of cardiovascular disease. There are no deleterious effects associated with reducing salt consumption and it is also very cost-effective. Many organizations and state governments have issued recommendations regarding the suitable amount of salt consumption. In France, the objective is a salt consumption<8g/day in men and<6.5g/day in women and children. As 80% of consumed salt comes from manufactured products in developed countries, reduction of salt consumption requires the participation of the food industry. The other tool is consumer information and education. Salt consumption has already decreased in France in recent years, but efforts must continue. Copyright © 2013 Elsevier Masson SAS. All rights reserved.
2017-03-16
When an active region rotated over to the edge of the sun, it presented us with a nice profile view of its elongated loops stretching and swaying above it (Mar. 8-9, 2017). These loops are actually charged particles (made visible in extreme ultraviolet light) swirling along the magnetic field lines of the active region. The video covers about 30 hours of activity. Also of note is a darker twisting mass of plasma to the left of the active region being pulled and spun about by magnetic forces. Video is available at http://photojournal.jpl.nasa.gov/catalog/PIA21562
Actinide removal from spent salts
Hsu, Peter C.; von Holtz, Erica H.; Hipple, David L.; Summers, Leslie J.; Adamson, Martyn G.
2002-01-01
A method for removing actinide contaminants (uranium and thorium) from the spent salt of a molten salt oxidation (MSO) reactor is described. Spent salt is removed from the reactor and analyzed to determine the contaminants present and the carbonate concentration. The salt is dissolved in water, and one or more reagents are added to precipitate the thorium as thorium oxide and/or the uranium as either uranium oxide or as a diuranate salt. The precipitated materials are filtered, dried and packaged for disposal as radioactive waste. About 90% of the thorium and/or uranium present is removed by filtration. After filtration, salt solutions having a carbonate concentration >20% can be dried and returned to the reactor for re-use. Salt solutions containing a carbonate concentration <20% require further clean-up using an ion exchange column, which yields salt solutions that contain less than 0.1 ppm of thorium or uranium.
Run-time parallelization and scheduling of loops
NASA Technical Reports Server (NTRS)
Saltz, Joel H.; Mirchandaney, Ravi; Crowley, Kay
1991-01-01
Run-time methods are studied to automatically parallelize and schedule iterations of a do loop in certain cases where compile-time information is inadequate. The methods presented involve execution time preprocessing of the loop. At compile-time, these methods set up the framework for performing a loop dependency analysis. At run-time, wavefronts of concurrently executable loop iterations are identified. Using this wavefront information, loop iterations are reordered for increased parallelism. Symbolic transformation rules are used to produce: inspector procedures that perform execution time preprocessing, and executors or transformed versions of source code loop structures. These transformed loop structures carry out the calculations planned in the inspector procedures. Performance results are presented from experiments conducted on the Encore Multimax. These results illustrate that run-time reordering of loop indexes can have a significant impact on performance.
Effect of Variable Emittance Coatings on the Operation of a Miniature Loop Heat Pipe
NASA Technical Reports Server (NTRS)
Douglas, Donya M.; Ku, Jentung; Ottenstein, Laura; Swanson, Theodore; Hess, Steve; Darrin, Ann
2005-01-01
Abstract. As the size of spacecraft shrink to accommodate small and more efficient instruments, smaller launch vehicles, and constellation missions, all subsystems must also be made smaller. Under NASA NFL4 03-OSS-02, Space Technology-8 (ST 8), NASA Goddard Space Flight Center and Jet Propulsion Laboratory jointly conducted a Concept Definition study to develop a miniature loop heat pipe (MLHP) thermal management system design suitable for future small spacecraft. The proposed MLHP thermal management system consists of a miniature loop heat pipe (LHP) and deployable radiators that are coated with variable emittance coatings (VECs). As part of the Phase A study and proof of the design concept, variable emittance coatings were integrated with a breadboard miniature loop heat pipe. The miniature loop heat pipe was supplied by the Jet Propulsion Laboratory (PL), while the variable emittance technology were supplied by Johns Hopkins University Applied Physics Laboratory and Sensortex, Inc. The entire system was tested under vacuum at various temperature extremes and power loads. This paper summarizes the results of this testing and shows the effect of the VEC on the operation of a miniature loop heat pipe.
Hyperstaticity and loops in frictional granular packings
NASA Astrophysics Data System (ADS)
Tordesillas, Antoinette; Lam, Edward; Metzger, Philip T.
2009-06-01
The hyperstatic nature of granular packings of perfectly rigid disks is analyzed algebraically and through numerical simulation. The elementary loops of grains emerge as a fundamental element in addressing hyperstaticity. Loops consisting of an odd number of grains behave differently than those with an even number. For odd loops, the latent stresses are exterior and are characterized by the sum of frictional forces around each loop. For even loops, the latent stresses are interior and are characterized by the alternating sum of frictional forces around each loop. The statistics of these two types of loop sums are found to be Gibbsian with a "temperature" that is linear with the friction coefficient μ when μ<1.
Loop Heat Pipe Startup Behaviors
NASA Technical Reports Server (NTRS)
Ku, Jentung
2016-01-01
A loop heat pipe must start successfully before it can commence its service. The startup transient represents one of the most complex phenomena in the loop heat pipe operation. This paper discusses various aspects of loop heat pipe startup behaviors. Topics include the four startup scenarios, the initial fluid distribution between the evaporator and reservoir that determines the startup scenario, factors that affect the fluid distribution between the evaporator and reservoir, difficulties encountered during the low power startup, and methods to enhance the startup success. Also addressed are the pressure spike and pressure surge during the startup transient, and repeated cycles of loop startup and shutdown under certain conditions.
One-loop renormalization of a gravity-scalar system
NASA Astrophysics Data System (ADS)
Park, I. Y.
2017-05-01
Extending the renormalizability proposal of the physical sector of 4D Einstein gravity, we have recently proposed renormalizability of the 3D physical sector of gravity-matter systems. The main goal of the present work is to conduct systematic one-loop renormalization of a gravity-matter system by applying our foliation-based quantization scheme. In this work we explicitly carry out renormalization of a gravity-scalar system with a Higgs-type potential. With the fluctuation part of the scalar field gauged away, the system becomes renormalizable through a metric field redefinition. We use dimensional regularization throughout. One of the salient aspects of our analysis is how the graviton propagator acquires the "mass" term. One-loop calculations lead to renormalization of the cosmological and Newton constants. We discuss other implications of our results as well: time-varying vacuum energy density and masses of the elementary particles as well as the potential relevance of Neumann boundary condition for black hole information.
Analysis and design of a 3rd order velocity-controlled closed-loop for MEMS vibratory gyroscopes.
Wu, Huan-ming; Yang, Hai-gang; Yin, Tao; Jiao, Ji-wei
2013-09-18
The time-average method currently available is limited to analyzing the specific performance of the automatic gain control-proportional and integral (AGC-PI) based velocity-controlled closed-loop in a micro-electro-mechanical systems (MEMS) vibratory gyroscope, since it is hard to solve nonlinear functions in the time domain when the control loop reaches to 3rd order. In this paper, we propose a linearization design approach to overcome this limitation by establishing a 3rd order linear model of the control loop and transferring the analysis to the frequency domain. Order reduction is applied on the built linear model's transfer function by constructing a zero-pole doublet, and therefore mathematical expression of each control loop's performance specification is obtained. Then an optimization methodology is summarized, which reveals that a robust, stable and swift control loop can be achieved by carefully selecting the system parameters following a priority order. Closed-loop drive circuits are designed and implemented using 0.35 μm complementary metal oxide semiconductor (CMOS) process, and experiments carried out on a gyroscope prototype verify the optimization methodology that an optimized stability of the control loop can be achieved by constructing the zero-pole doublet, and disturbance rejection capability (D.R.C) of the control loop can be improved by increasing the integral term.
Salt briquette: the form of salt monopoly in madura, 1883-1911
NASA Astrophysics Data System (ADS)
Wisnu; Alrianingrum, S.; Artono; Liana, C.
2018-01-01
This study describes the history of the salt monopoly in Indonesia because it is associated with the issue of salt crisis lately, widely reported in various media. This study tried to find answers to the relationship between monopoly and crisis events through the study of history. Monopoly policy by the government of the colonial period is actually an industrial modernization effort, but it turned out another impact. Although the colonial government wanted to issue a policy that ends strengthens the position of the government in the industry, but ultimately backfire and disasters in the salt industry at the time. This article discusses only the focus of the salt monopoly in Madura as a selection of events, arguing the island as a center of salt in Indonesia. The method used in this study using a review of history. Therefore, their explanations using historical sources. Methodologically through the process of collecting historical sources, criticize these sources, synthesize and interpret the analysis in an array of historical writing. In conclusion, although the salt monopoly policy gives a great advantage to the colonial government, but the overall population of Madura remains in a poor state. It is evident that the Madurese to migrate Madurese to various areas outside the island of Madura, to fix the economy.
Dynamics of salt playa polygons
NASA Astrophysics Data System (ADS)
Goehring, L.; Fourrière, A.
2014-12-01
In natural salt playa or in evaporation pools for the salt extraction industry, one can sometimes see surprising regular structures formed by ridges of salt. These ridges connect together to form a self-organized network of polygons one to two meters in diameter, which we call salt polygons. Here we propose a mechanism based on porous media convection of salty water in soil to explain the formation and the scaling of the salt polygons. Surface evaporation causes a steady upward flow of salty water, which can cause precipitation near the surface. A vertical salt gradient then builds up in the porous soil, with heavy salt-saturated water lying over the less salty source water. This can drive convection when a threshold is reached, given by a critical Rayleigh number of about 7. We suggest that the salt polygons are the surface expression of the porous medium convection, with salt crystallizing along the positions of the convective downwellings. To study this instability directly, we developed a 2D analogue experiment using a Hele-Shaw cell filled with a porous medium saturated with a salt solution and heated from above. We perform a linear stability analysis of this system, and find that it is unstable to convection, with a most unstable wavelength that is set by a balance between salt diffusion and water evaporation. The Rayleigh number in our experiment is controlled by the particle size of our model soil, and the evaporation rate. We obtain results that scale with the observation of natural salt polygons. Using dye, we observe the convective movement of salty water and find downwelling convective plumes underneath the spots where surface salt ridges form, as shown in the attached figure.
NASA Technical Reports Server (NTRS)
Cliff, R. A. (Inventor)
1975-01-01
An digital phase-locked loop is provided for deriving a loop output signal from an accumulator output terminal. A phase detecting exclusive OR gate is fed by the loop digital input and output signals. The output of the phase detector is a bi-level digital signal having a duty cycle indicative of the relative phase of the input and output signals. The accumulator is incremented at a first rate in response to a first output level of the phase detector and at a second rate in response to a second output level of the phase detector.
Sanphui, Palash; Tothadi, Srinu; Ganguly, Somnath; Desiraju, Gautam R
2013-12-02
Sildenafil is a drug used to treat erectile dysfunction and pulmonary arterial hypertension. Because of poor aqueous solubility of the drug, the citrate salt, with improved solubility and pharmacokinetics, has been marketed. However, the citrate salt requires an hour to reach its peak plasma concentration. Thus, to improve solubility and bioavailability characteristics, cocrystals and salts of the drug have been prepared by treating aliphatic dicarboxylic acids with sildenafil; the N-methylated piperazine of the drug molecule interacts with the carboxyl group of the acid to form a heterosynthon. Salts are formed with oxalic and fumaric acid; salt monoanions are formed with succinic and glutaric acid. Sildenafil forms cocrystals with longer chain dicarboxylic acids such as adipic, pimelic, suberic, and sebacic acids. Auxiliary stabilization via C-H···O interactions is also present in these cocrystals and salts. Solubility experiments of sildenafil cocrystal/salts were carried out in 0.1N HCl aqueous medium and compared with the solubility of the citrate salt. The glutarate salt and pimelic acid cocrystal dissolve faster than the citrate salt in a two hour dissolution experiment. The glutarate salt exhibits improved solubility (3.2-fold) compared to the citrate salt in water. Solubilities of the binary salts follow an inverse correlation with their melting points, while the solubilities of the cocrystals follow solubilities of the coformer. Pharmacokinetic studies on rats showed that the glutarate salt exhibits doubled plasma AUC values in a single dose within an hour compared to the citrate salt. The high solubility of glutaric acid, in part originating from the strained conformation of the molecule and its high permeability, may be the reason for higher plasma levels of the drug.
Metals removal from spent salts
Hsu, Peter C.; Von Holtz, Erica H.; Hipple, David L.; Summers, Leslie J.; Brummond, William A.; Adamson, Martyn G.
2002-01-01
A method and apparatus for removing metal contaminants from the spent salt of a molten salt oxidation (MSO) reactor is described. Spent salt is removed from the reactor and analyzed to determine the contaminants present and the carbonate concentration. The salt is dissolved in water, and one or more reagents may be added to precipitate the metal oxide and/or the metal as either metal oxide, metal hydroxide, or as a salt. The precipitated materials are filtered, dried and packaged for disposal as waste or can be immobilized as ceramic pellets. More than about 90% of the metals and mineral residues (ashes) present are removed by filtration. After filtration, salt solutions having a carbonate concentration >20% can be spray-dried and returned to the reactor for re-use. Salt solutions containing a carbonate concentration <20% require further clean-up using an ion exchange column, which yields salt solutions that contain less than 1.0 ppm of contaminants.
Jastremski, M; Jastremski, C; Shepherd, M; Friedman, V; Porembka, D; Smith, R; Gonzales, E; Swedlow, D; Belzberg, H; Crass, R
1995-10-01
To test a model for the assessment of critical care technology on closed loop infusion control, a technology that is in its early stages of development and testing on human subjects. A computer-assisted search of the English language literature and reviews of the gathered data by experts in the field of closed loop infusion control systems. Studies relating to closed loop infusion control that addressed one or more of the questions contained in our technology assessment template were analyzed. Study design was not a factor in article selection. However, the lack of well-designed clinical outcome studies was an important factor in determining our conclusions. A focus person summarized the data from the selected studies that related to each of the assessment questions. The preliminary data summary developed by the focus person was further analyzed and refined by the task force. Experts in closed loop systems were then added to the group to review the summary provided by the task force. These experts' comments were considered by the task force and this final consensus report was developed. Closed loop system control is a technological concept that may be applicable to several aspects of critical care practice. This is a technology in the early stages of evolution and much more research and data are needed before its introduction into usual clinical practice. Furthermore, each specific application and each device for each application (e.g., nitroprusside infusion, ventilator adjustment), although based on the same technological concept, are sufficiently different in terms of hardware and computer algorithms to require independent validation studies. Closed loop infusion systems may have a role in critical care practice. However, for most applications, further development is required to move this technology from the innovation phase to the point where it can be evaluated so that its role in critical car practice can be defined. Each application of closed loop infusion
Niessen, Ludwig
2015-01-01
Loop-mediated isothermal amplification is a rather novel method of enzymatic deoxyribonucleic acid amplification which can be applied for the diagnosis of viruses, bacteria, and fungi. Although firmly established in viral and bacterial diagnosis, the technology has only recently been applied to a noteworthy number of species in the filamentous fungi and yeasts. The current review gives an overview of the literature so far published on the topic by discussing the different groups of fungal organisms to which the method has been applied. Moreover, the method is described in detail as well as the different possibilities available for signal detection and quantification and sample preparation. Future perspective of loop-mediated isothermal amplification-based assays is discussed in the light of applicability for fungal diagnostics.
Campos, Juan F; Cara, Beatriz; Pérez-Martín, Fernando; Pineda, Benito; Egea, Isabel; Flores, Francisco B; Fernandez-Garcia, Nieves; Capel, Juan; Moreno, Vicente; Angosto, Trinidad; Lozano, Rafael; Bolarin, Maria C
2016-06-01
A screening under salt stress conditions of a T-DNA mutant collection of tomato (Solanum lycopersicum L.) led to the identification of the altered response to salt stress 1 (ars1) mutant, which showed a salt-sensitive phenotype. Genetic analysis of the ars1 mutation revealed that a single T-DNA insertion in the ARS1 gene was responsible of the mutant phenotype. ARS1 coded for an R1-MYB type transcription factor and its expression was induced by salinity in leaves. The mutant reduced fruit yield under salt acclimation while in the absence of stress the disruption of ARS1 did not affect this agronomic trait. The stomatal behaviour of ars1 mutant leaves induced higher Na(+) accumulation via the transpiration stream, as the decreases of stomatal conductance and transpiration rate induced by salt stress were markedly lower in the mutant plants. Moreover, the mutation affected stomatal closure in a response mediated by abscisic acid (ABA). The characterization of tomato transgenic lines silencing and overexpressing ARS1 corroborates the role of the gene in regulating the water loss via transpiration under salinity. Together, our results show that ARS1 tomato gene contributes to reduce transpirational water loss under salt stress. Finally, this gene could be interesting for tomato molecular breeding, because its manipulation could lead to improved stress tolerance without yield penalty under optimal culture conditions. © 2015 Society for Experimental Biology, Association of Applied Biologists and John Wiley & Sons Ltd.
Wold, Steven R.; Thomas, Blakemore E.; Waddell, Kidd M.
1997-01-01
The water and salt balance of Great Salt Lake primarily depends on the amount of inflow from tributary streams and the conveyance properties of a causeway constructed during 1957-59 that divides the lake into the south and north parts. The conveyance properties of the causeway originally included two culverts, each 15 feet wide, and the permeable rock-fill material.During 1980-86, the salt balance changed as a result of record high inflow that averaged 4,627,000 acre-feet annually and modifications made to the conveyance properties of the causeway that included opening a 300-foot-wide breach. In this study, a model developed in 1973 by Waddell and Bolke to simulate the water and salt balance of the lake was revised to accommodate the high water-surface altitude and modifications made to the causeway. This study, done by the U.S. Geological Survey in cooperation with the Utah Department of Natural Resources, Division of State Lands and Forestry, updates the model with monitoring data collected during 1980-86. This report describes the calibration of the model and presents the results of simulations for three hypothetical 10-year periods.During January 1, 1980, to July 31, 1984, a net load of 0.5 billion tons of dissolved salt flowed from the south to the north part of the lake primarily as a result of record inflows. From August 1, 1984, when the breach was opened, to December 31,1986, a net load of 0.3 billion tons of dissolved salt flowed from the north to the south part of the lake primarily as a result of the breach.For simulated inflow rates during a hypothetical 10-year period resulting in the water-surface altitude decreasing from about 4,200 to 4,192 feet, there was a net movement of about 1.0 billion tons of dissolved salt from the south to the north part, and about 1.7 billion tons of salt precipitated in the north part. For simulated inflow rates during a hypothetical 10-year period resulting in a rise in water-surface altitude from about 4,200 to 4
Salt Reductions in Some Foods in The Netherlands: Monitoring of Food Composition and Salt Intake
Temme, Elisabeth H. M.; Hendriksen, Marieke A. H.; Milder, Ivon E. J.; Toxopeus, Ido B.; Westenbrink, Susanne; Brants, Henny A. M.; van der A, Daphne L.
2017-01-01
Background and objectives. High salt intake increases blood pressure and thereby the risk of chronic diseases. Food reformulation (or food product improvement) may lower the dietary intake of salt. This study describes the changes in salt contents of foods in the Dutch market over a five-year period (2011–2016) and differences in estimated salt intake over a 10-year period (2006–2015). Methods. To assess the salt contents of foods; we obtained recent data from chemical analyses and from food labels. Salt content of these foods in 2016 was compared to salt contents in the 2011 version Dutch Food Composition Database (NEVO, version 2011), and statistically tested with General Linear Models. To estimate the daily dietary salt intake in 2006, 2010, and 2015, men and women aged 19 to 70 years were recruited through random population sampling in Doetinchem, a small town located in a rural area in the eastern part of the Netherlands. The characteristics of the study population were in 2006: n = 317, mean age 49 years, 43% men, in 2010: n = 342, mean age 46 years, 45% men, and in 2015: n = 289, mean age 46 years, 47% men. Sodium and potassium excretion was measured in a single 24-h urine sample. All estimates were converted to a common metric: salt intake in grams per day by multiplication of sodium with a factor of 2.54. Results. In 2016 compared to 2011, the salt content in certain types of bread was on average 19 percent lower and certain types of sauce, soup, canned vegetables and legumes, and crisps had a 12 to 26 percent lower salt content. Salt content in other types of foods had not changed significantly. Between 2006, 2010 and 2015 the estimated salt intake among adults in Doetinchem remained unchanged. In 2015, the median estimated salt intake was 9.7 g per day for men and 7.4 g per day for women. As in 2006 and 2010, the estimated salt intake in 2015 exceeded the recommended maximum intake of 6 g per day set by the Dutch Health Council. Conclusion. In the
Salt Reductions in Some Foods in The Netherlands: Monitoring of Food Composition and Salt Intake.
Temme, Elisabeth H M; Hendriksen, Marieke A H; Milder, Ivon E J; Toxopeus, Ido B; Westenbrink, Susanne; Brants, Henny A M; van der A, Daphne L
2017-07-22
High salt intake increases blood pressure and thereby the risk of chronic diseases. Food reformulation (or food product improvement) may lower the dietary intake of salt. This study describes the changes in salt contents of foods in the Dutch market over a five-year period (2011-2016) and differences in estimated salt intake over a 10-year period (2006-2015). To assess the salt contents of foods; we obtained recent data from chemical analyses and from food labels. Salt content of these foods in 2016 was compared to salt contents in the 2011 version Dutch Food Composition Database (NEVO, version 2011), and statistically tested with General Linear Models. To estimate the daily dietary salt intake in 2006, 2010, and 2015, men and women aged 19 to 70 years were recruited through random population sampling in Doetinchem, a small town located in a rural area in the eastern part of the Netherlands. The characteristics of the study population were in 2006: n = 317, mean age 49 years, 43% men, in 2010: n = 342, mean age 46 years, 45% men, and in 2015: n = 289, mean age 46 years, 47% men. Sodium and potassium excretion was measured in a single 24-h urine sample. All estimates were converted to a common metric: salt intake in grams per day by multiplication of sodium with a factor of 2.54. In 2016 compared to 2011, the salt content in certain types of bread was on average 19 percent lower and certain types of sauce, soup, canned vegetables and legumes, and crisps had a 12 to 26 percent lower salt content. Salt content in other types of foods had not changed significantly. Between 2006, 2010 and 2015 the estimated salt intake among adults in Doetinchem remained unchanged. In 2015, the median estimated salt intake was 9.7 g per day for men and 7.4 g per day for women. As in 2006 and 2010, the estimated salt intake in 2015 exceeded the recommended maximum intake of 6 g per day set by the Dutch Health Council. In the Netherlands, the salt content of bread, certain sauces, soups
NASA Astrophysics Data System (ADS)
Volkov, Sergey
2017-11-01
This paper presents a new method of numerical computation of the mass-independent QED contributions to the electron anomalous magnetic moment which arise from Feynman graphs without closed electron loops. The method is based on a forestlike subtraction formula that removes all ultraviolet and infrared divergences in each Feynman graph before integration in Feynman-parametric space. The integration is performed by an importance sampling Monte-Carlo algorithm with the probability density function that is constructed for each Feynman graph individually. The method is fully automated at any order of the perturbation series. The results of applying the method to 2-loop, 3-loop, 4-loop Feynman graphs, and to some individual 5-loop graphs are presented, as well as the comparison of this method with other ones with respect to Monte Carlo convergence speed.
Method of implementing digital phase-locked loops
NASA Technical Reports Server (NTRS)
Stephens, Scott A. (Inventor); Thomas, Jess Brooks, Jr. (Inventor)
1993-01-01
In a new formulation for digital phase-locked loops, loop-filter constants are determined from loop roots that can each be selectively placed in the s-plane on the basis of a new set of parameters, each with simple and direct physical meaning in terms of loop noise bandwidth, root-specific decay rate, or root-specific damping. Loops of first to fourth order are treated in the continuous-update approximation (BLT yields 0) and in a discrete-update formulation with arbitrary BLT. Deficiencies of the continuous-update approximation in large-BLT applications are avoided in the new discrete-update formulation. A new method for direct, transient-free acquisition with third- and fourth-order loops can improve the versatility and reliability of acquisition with such loops.
The Sustainability Cycle and Loop: models for a more unified understanding of sustainability.
Hay, Laura; Duffy, Alex; Whitfield, R I
2014-01-15
In spite of the considerable research on sustainability, reports suggest that we are barely any closer to a more sustainable society. As such, there is an urgent need to improve the effectiveness of human efforts towards sustainability. A clearer and more unified understanding of sustainability among different people and sectors could help to facilitate this. This paper presents the results of an inductive literature investigation, aiming to develop models to explain the nature of sustainability in the Earth system, and how humans can effectively strive for it. The major contributions are two general and complementary models, that may be applied in any context to provide a common basis for understanding sustainability: the Sustainability Cycle (S-Cycle), and the Sustainability Loop (S-Loop). Literature spanning multiple sectors is examined from the perspective of three concepts, emerging as significant in relation to our aim. Systems are shown to provide the context for human action towards sustainability, and the nature of the Earth system and its sub-systems is explored. Activities are outlined as a fundamental target that humans need to sustain, since they produce the entities both needed and desired by society. The basic behaviour of activities operating in the Earth system is outlined. Finally, knowledge is positioned as the driver of human action towards sustainability, and the key components of knowledge involved are examined. The S-Cycle and S-Loop models are developed via a process of induction from the reviewed literature. The S-Cycle describes the operation of activities in a system from the perspective of sustainability. The sustainability of activities in a system depends upon the availability of resources, and the availability of resources depends upon the rate that activities consume and produce them. Humans may intervene in these dynamics via an iterative process of interpretation and action, described in the S-Loop model. The models are briefly
Observations of loops and prominences
NASA Technical Reports Server (NTRS)
Strong, Keith T.
1994-01-01
We review recent observations by the Yohkoh-SXT (Soft X-ray Telescope) in collaboration with other spacecraft and ground-based observatories of coronal loops and prominences. These new results point to problems that SoHO will be able to address. With a unique combination of rapid-cadence digital imaging (greater than or equal to 32 s full-disk and greater than or equal to 2 s partial-frame images), high spatial resolution (greater than or equal to 2.5 arcsec pixels), high sensitivity (EM less than or equal to 10(exp 42) cm(exp -3)), a low-scatter mirror, and large dynamic range, SXT can observe a vast range of targets on the Sun. Over the first 21 months of Yohkoh operations SXT has taken over one million images of the corona and so is building up an invaluable long-term database on the large-scale corona and loop geometry. The most striking thing about the SXT images is the range of loop sizes and shapes. The active regions are a bright tangle of magnetic field lines, surrounded by a network of large-scale quiet-Sun loops stretching over distances in excess of 105 km. The cross-section of most loops seems to be constant. Loops displaying significant Gamma's are the exception, not the rule, implying the presence of widespread currents in the corona. All magnetic structures show changes. Time scales range from seconds to months. The question of how these structures are formed, become filled with hot plasma, and are maintained is still open. While we see the propagation of brightenings along the length of active-region loops and in X-ray jets with velocities of several hundred km/s, much higher velocities are seen in the quiet Sun. In XBP flares, for example, velocities of over 1000 km/s are common. Active-region loops seem to be in constant motion, moving slowly outward, carrying plasma with them. During flares, loops often produce localized brightenings at the base and later at the apex of the loop. Quiescent filaments and prominences have been observed regularly
Plant salt-tolerance mechanisms
Deinlein, Ulrich; Stephan, Aaron B.; Horie, Tomoaki; ...
2014-06-01
Crop performance is severely affected by high salt concentrations in soils. To engineer more salt-tolerant plants it is crucial to unravel the key components of the plant salt-tolerance network. Here we review our understanding of the core salt-tolerance mechanisms in plants. Recent studies have shown that stress sensing and signaling components can play important roles in regulating the plant salinity stress response. We also review key Na+ transport and detoxification pathways and the impact of epigenetic chromatin modifications on salinity tolerance. In addition, we discuss the progress that has been made towards engineering salt tolerance in crops, including marker-assisted selectionmore » and gene stacking techniques. We also identify key open questions that remain to be addressed in the future.« less
Salt tolerant green crop species for sodium management in space agriculture
NASA Astrophysics Data System (ADS)
Yamashita, Masamichi; Hashimoto, Hirofumi; Tomita-Yokotani, Kaori; Shimoda, Toshifumi; Nose, Akihiro; Space Agriculture Task Force, J.
Ecological system and materials recycling loop of space agriculture are quite tight compared to natural ecological system on Earth. Sodium management will be a keen issue for space agricul-ture. Human nutritional requirements include sodium salt. Since sodium at high concentration is toxic for most of plant growth, excreted sodium of human waste should be removed from compost fertilizer. Use of marine algae is promising for harvesting potassium and other min-erals required for plant growth and returning remained sodium to satisfy human need of its intake. Farming salt tolerant green crop species is another approach to manage sodium problem in both space and terrestrial agriculture. We chose ice plant and New Zealand spinach. These two plant species are widely accepted green vegetable with many recipe. Ice plant can grow at the salinity level of sea water, and contain sodium salt up to 30% of its dry mass. Sodium distributes mainly in its bladder cells. New Zealand spinach is a plant species found in the front zone of sea shore, and tolerant against high salinity as well. Plant body size of both species at harvest is quite large, and easy to farm. Capability of bio-remediation of high saline soil is examined with ice plant and New Zealand spinach. Incubation medium was chosen to contain high concentration of sodium and potassium at the Na/K ratio of human excreta. In case Na/K ratio of plant body grown by this medium is greatly higher than that of incubation medium or soil, these halophytes are effective to remediate soil for farming less tolerant plant crop. Experimental results was less positive in this context.
Early evolution of salt structures in north Louisiana salt basin
DOE Office of Scientific and Technical Information (OSTI.GOV)
Lobao, J.J.; Pilger, R.H. Jr.
1986-05-01
Several salt diapirs and pillows in southern and central north Louisiana have been studied using approximately 355 mi (570 km) of seismic reflection data and information from 57 deep well holes. Using seismic profiles with deep well-hole data is the most advantageous method to document regional salt tectonism through time. The following conclusions were reached on diapirism in the North Louisiana Salt basin. (1) The diapiric event began early (early Coahuilan) in the southern and central part of the basin, and later (late Coahuilan to Comanchean) in the northern part. (2) The initial diapiric event is much more abrupt andmore » intense in the southern and central diapirs when compared with the later diapiric event in the northern diapirs. (3) Regional depocenter shifting, relative sea level, local erosion with salt extrusion, and rapid depositional loading of sediments are the major controls on diapirism in the basin.« less
NASA Astrophysics Data System (ADS)
Jagoutz, E.
Large well rounded boulders and angular rock fragments characterizes the Martian landscape as seen on the recent excellent quality photos. Analyzing the different rock-shapes indicates a time sequence of emplacement, fragmentation and transport of different rocks on Mars, which might give interesting insight into transport and weathering processes. Larger commonly well rounded boulders were emplaced onto gravel plains. After emplacement, these rocks were fragmented and disassembled. Nests of angular rock fragments are marking the locations of preexisting larger rocks. Frequently it is possible to reconstruct larger rounded rocks from smaller angular fragments. In other cases transport after fragmentation obscured the relationship of the fragments. However, a strewn field of fragments is still reminiscent of the preexisting rock. Mechanical salt weathering could be a plausible explanation for the insitu fragmentation of larger rounded blocks into angular fragments. Impact or secondary air fall induced fragmentation produces very different patterns, as observed around impact crates on Earth. Salt weathering of rocks is a common process in terrestrial environments. Salt crystallization in capillaries causes fragmentation of rocks, irrespective of the process of salt transportation and concentration. On Earth significant salt weathering can be observed in different climatic environments: in the transition zone of alluvial aprons and salt playas in desserts and in dry valleys of Antarctica. In terrestrial semi-arid areas the salt is transported by salt solution, which is progressively concentrated by evaporation. In Antarctic dry valleys freeze-thaw cycles causes salt transportation and crystallization resulting in rock fragmentation. This salt induced process can lead to complete destruction of rocks and converts rocks to fine sand. The efficient breakdown of rocks is dominating the landscape in some dry valleys of the Earth but possibly also on Mars. (Malin, 1974
A social feedback loop for speech development and its reduction in autism
Warlaumont, Anne S.; Richards, Jeffrey A.; Gilkerson, Jill; Oller, D. Kimbrough
2014-01-01
We analyze the microstructure of child-adult interaction during naturalistic, daylong, automatically labeled audio recordings (13,836 hours total) of children (8- to 48-month-olds) with and without autism. We find that adult responses are more likely when child vocalizations are speech-related. In turn, a child vocalization is more likely to be speech-related if the previous speech-related child vocalization received an immediate adult response. Taken together, these results are consistent with the idea that there is a social feedback loop between child and caregiver that promotes speech-language development. Although this feedback loop applies in both typical development and autism, children with autism produce proportionally fewer speech-related vocalizations and the responses they receive are less contingent on whether their vocalizations are speech-related. We argue that such differences will diminish the strength of the social feedback loop with cascading effects on speech development over time. Differences related to socioeconomic status are also reported. PMID:24840717
Electron Injection by E-Field Drift and its Application in Starting-up Tokamaks at Low Loop Voltage
NASA Astrophysics Data System (ADS)
Pan, Yuan; Yan, Xiao-Lin; Liu, Bao-Hua
2003-05-01
We propose an innovative method of electron injection by E-field drift into a plasma device and discuss its application in starting-up tokamak plasmas at low loop voltage. The experimental results obtained from HT-6M Tokamak are also presented. The breakdown loop voltage is obviously reduced and the discharge performance is improved by using the electron injection method. It could be applied to some other types of plasma device.
Conceptualization and validation of an open-source closed-loop deep brain stimulation system in rat.
Wu, Hemmings; Ghekiere, Hartwin; Beeckmans, Dorien; Tambuyzer, Tim; van Kuyck, Kris; Aerts, Jean-Marie; Nuttin, Bart
2015-04-21
Conventional deep brain stimulation (DBS) applies constant electrical stimulation to specific brain regions to treat neurological disorders. Closed-loop DBS with real-time feedback is gaining attention in recent years, after proved more effective than conventional DBS in terms of pathological symptom control clinically. Here we demonstrate the conceptualization and validation of a closed-loop DBS system using open-source hardware. We used hippocampal theta oscillations as system input, and electrical stimulation in the mesencephalic reticular formation (mRt) as controller output. It is well documented that hippocampal theta oscillations are highly related to locomotion, while electrical stimulation in the mRt induces freezing. We used an Arduino open-source microcontroller between input and output sources. This allowed us to use hippocampal local field potentials (LFPs) to steer electrical stimulation in the mRt. Our results showed that closed-loop DBS significantly suppressed locomotion compared to no stimulation, and required on average only 56% of the stimulation used in open-loop DBS to reach similar effects. The main advantages of open-source hardware include wide selection and availability, high customizability, and affordability. Our open-source closed-loop DBS system is effective, and warrants further research using open-source hardware for closed-loop neuromodulation.
Conceptualization and validation of an open-source closed-loop deep brain stimulation system in rat
Wu, Hemmings; Ghekiere, Hartwin; Beeckmans, Dorien; Tambuyzer, Tim; van Kuyck, Kris; Aerts, Jean-Marie; Nuttin, Bart
2015-01-01
Conventional deep brain stimulation (DBS) applies constant electrical stimulation to specific brain regions to treat neurological disorders. Closed-loop DBS with real-time feedback is gaining attention in recent years, after proved more effective than conventional DBS in terms of pathological symptom control clinically. Here we demonstrate the conceptualization and validation of a closed-loop DBS system using open-source hardware. We used hippocampal theta oscillations as system input, and electrical stimulation in the mesencephalic reticular formation (mRt) as controller output. It is well documented that hippocampal theta oscillations are highly related to locomotion, while electrical stimulation in the mRt induces freezing. We used an Arduino open-source microcontroller between input and output sources. This allowed us to use hippocampal local field potentials (LFPs) to steer electrical stimulation in the mRt. Our results showed that closed-loop DBS significantly suppressed locomotion compared to no stimulation, and required on average only 56% of the stimulation used in open-loop DBS to reach similar effects. The main advantages of open-source hardware include wide selection and availability, high customizability, and affordability. Our open-source closed-loop DBS system is effective, and warrants further research using open-source hardware for closed-loop neuromodulation. PMID:25897892
Inguglia, Elena S; Zhang, Zhihang; Burgess, Catherine; Kerry, Joseph P; Tiwari, Brijesh K
2018-02-01
The present study investigated the effect of geometric parameters of the ultrasound instrument during meat salting in order to enhance salt diffusion and salt distribution in pork meat on a lab scale. The effects of probe size (∅2.5 and 1.3cm) and of different distances between the transducer and the meat sample (0.3, 0.5, and 0.8cm) on NaCl diffusion were investigated. Changes in the moisture content and NaCl gain were used to evaluate salt distribution and diffusion in the samples, parallel and perpendicular to ultrasound propagation direction. Results showed that 0.3cm was the most efficient distance between the probe and the sample to ensure a higher salt diffusion rate. A distance of 0.5cm was however considered as a trade-off distance to ensure salt diffusion and maintenance of meat quality parameters. The enhancement of salt diffusion by ultrasound was observed to decrease with increased horizontal distance from the probe. This study is of valuable importance for meat processing industries willing to apply new technologies on a larger scale and with defined operational standards. The data suggest that the geometric parameters of ultrasound systems can have strong influence on the efficiency of ultrasonic enhancement of NaCl uptake in meat and can be a crucial element in determining salt uptake during meat processing. Copyright © 2017 Elsevier B.V. All rights reserved.
Combinations of fluorinated solvents with imide salts or methide salts for electrolytes
Tikhonov, Konstantin; Yip, Ka Ki; Lin, Tzu-Yuan; Lei, Norman; Guerrero-Zavala, Guillermo; Kwong, Kristie W
2015-11-10
Provided are electrochemical cells and electrolytes used to build such cells. The electrolytes include imide salts and/or methide salts as well as fluorinated solvents capable of maintaining single phase solutions at between about -30.degree. C. to about 80.degree. C. The fluorinated solvents, such as fluorinated carbonates, fluorinated esters, and fluorinated esters, are less flammable than their non-fluorinated counterparts and improve safety characteristics of cells containing these solvents. The amount of fluorinated solvents in electrolytes may be between about 30% and 80% by weight not accounting weight of the salts. Linear and cyclic imide salts, such as LiN(SO.sub.2CF.sub.2CF.sub.3).sub.2, and LiN(SO.sub.2CF.sub.3).sub.2, as well as methide salts, such as LiC(SO.sub.2CF.sub.3).sub.3 and LiC(SO.sub.2CF.sub.2CF.sub.3).sub.3, may be used in these electrolytes. Fluorinated alkyl groups enhance solubility of these salts in the fluorinated solvents. In some embodiments, the electrolyte may also include a flame retardant, such as a phosphazene, and/or one or more ionic liquids.
MHD Modelling of Coronal Loops: Injection of High-Speed Chromospheric Flows
NASA Technical Reports Server (NTRS)
Petralia, A.; Reale, F.; Orlando, S.; Klimchuk, J. A.
2014-01-01
Context. Observations reveal a correspondence between chromospheric type II spicules and bright upward-moving fronts in the corona observed in the extreme-ultraviolet (EUV) band. However, theoretical considerations suggest that these flows are probably not the main source of heating in coronal magnetic loops. Aims. We investigate the propagation of high-speed chromospheric flows into coronal magnetic flux tubes and the possible production of emission in the EUV band. Methods. We simulated the propagation of a dense 104 K chromospheric jet upward along a coronal loop by means of a 2D cylindrical MHD model that includes gravity, radiative losses, thermal conduction, and magnetic induction. The jet propagates in a complete atmosphere including the chromosphere and a tenuous cool (approximately 0.8 MK) corona, linked through a steep transition region. In our reference model, the jet initial speed is 70 km per second, its initial density is 10(exp 11) per cubic centimeter, and the ambient uniform magnetic field is 10 G. We also explored other values of jet speed and density in 1D and different magnetic field values in 2D, as well as the jet propagation in a hotter (approximately 1.5 MK) background loop. Results. While the initial speed of the jet does not allow it to reach the loop apex, a hot shock-front develops ahead of it and travels to the other extreme of the loop. The shock front compresses the coronal plasma and heats it to about 10(exp 6) K. As a result, a bright moving front becomes visible in the 171 Angstrom channel of the SDO/AIA mission. This result generally applies to all the other explored cases, except for the propagation in the hotter loop. Conclusions. For a cool, low-density initial coronal loop, the post-shock plasma ahead of upward chromospheric flows might explain at least part of the observed correspondence between type II spicules and EUV emission excess.
Assessment of soil and wash water quality beneath salt-spreader racks.
DOT National Transportation Integrated Search
2008-01-01
The Virginia Department of Transportation's (VDOT) winter maintenance program hinges primarily on the use of granular NaCl for deicing. On average, VDOT applies more than 300,000 tons of NaCl each winter season. The majority of this salt is spread by...
Near optimum digital phase locked loops.
NASA Technical Reports Server (NTRS)
Polk, D. R.; Gupta, S. C.
1972-01-01
Near optimum digital phase locked loops are derived utilizing nonlinear estimation theory. Nonlinear approximations are employed to yield realizable loop structures. Baseband equivalent loop gains are derived which under high signal to noise ratio conditions may be calculated off-line. Additional simplifications are made which permit the application of the Kalman filter algorithms to determine the optimum loop filter. Performance is evaluated by a theoretical analysis and by simulation. Theoretical and simulated results are discussed and a comparison to analog results is made.
Salt fluoridation and oral health.
Marthaler, Thomas M
2013-11-01
The aim of this paper is to make known the potential of fluoridated salt in community oral health programs, particularly in South Eastern Europe. Since 1922, the addition of iodine to salt has been successful in Switzerland. Goiter is virtually extinct. By 1945, the caries-protective effect of fluorides was well established. Based on the success of water fluoridation, a gynecologist started adding of fluoride to salt. The sale of fluoridated salt began in 1956 in the Swiss Canton of Zurich, and several other cantons followed suit. Studies initiated in the early seventies showed that fluoride, when added to salt, inhibits dental caries. The addition of fluoride to salt for human consumption was officially authorized in 1980-82. In Switzerland 85% of domestic salt consumed is fluoridated and 67% in Germany. Salt fluoridation schemes are reaching more than one hundred million in Mexico, Colombia, Peru and Cuba. The cost of salt fluoridation is very low, within 0.02 and 0.05 € per year and capita. Children and adults of the low socio-economic strata tend to have substantially more untreated caries than higher strata. Salt fluoridation is by far the cheapest method for improving oral health. Salt fluoridation has cariostatic potential like water fluoridation (caries reductions up to 50%). In Europe, meaningful percentages of users have been attained only in Germany (67%) and Switzerland (85%). In Latin America, there are more than 100 million users, and several countries have arrived at coverage of 90 to 99%. Salt fluoridation is by far the cheapest method of caries prevention, and billions of people throughout the world could benefit from this method. Copyright © 2013 by Academy of Sciences and Arts of Bosnia and Herzegovina.
Swapnil, Prashant; Rai, Ashwani K
2018-05-01
Soil salinity in nature is generally mixed type; however, most of the studies on salt toxicity are performed with NaCl and little is known about sulfur type of salinity (Na 2 SO 4 ). Present study discerns the physiologic mechanisms responsible for salt tolerance in salt-adapted Anabaena fertilissima, and responses of directly stressed parent cells to NaCl and NaCl+Na 2 SO 4 mixture. NaCl at 500 mM was lethal to the cyanobacterium, whereas salt-adapted cells grew luxuriantly. Salinity impaired gross photosynthesis, electron transport activities, and respiration in parent cells, but not in the salt-adapted cells, except a marginal increase in PSI activity. Despite higher Na + concentration in the salt mixture, equimolar NaCl appeared more inhibitive to growth. Sucrose and trehalose content and antioxidant activities were maximal in 250 mM NaCl-treated cells, followed by salt mixture and was almost identical in salt-adapted (exposed to 500 mm NaCl) and control cells, except a marginal increase in ascorbate peroxidase activity and an additional fourth superoxide dismutase isoform. Catalase isoform of 63 kDa was induced only in salt-stressed cells. Salinity increased the uptake of intracellular Na + and Ca 2+ and leakage of K + in parent cells, while cation level in salt-adapted cells was comparable to control. Though there was differential increase in intracellular Ca 2+ under different salt treatments, ratio of Ca 2+ /Na + remained the same. It is inferred that stepwise increment in the salt concentration enabled the cyanobacterium to undergo priming effect and acquire robust and efficient defense system involving the least energy.
Applied Neuroscience at the AFRL 711th Human Performance Wing
2010-09-01
Support teaming and collaboration research performed by RHCPT 25 History of Applied Neuroscience Research First EEG studies of workload at AFRL...First to classify mental workload based on integrated EEG /ECG 26 First successful real- time workload classification Measured EEG workload in...complex tasks Closed-loop adaptive aiding based on EEG /ECG History of Applied Neuroscience Research 27 Current Applied Neuroscience Research • Mix of in
Materials corrosion in molten lithium fluoride-sodium fluoride-potassium fluoride eutectic salt
NASA Astrophysics Data System (ADS)
Olson, Luke Christopher
Static corrosion studies were undertaken to determine the compatibility of several candidate high temperature materials for a heat transfer loop in a molten alkali fluoride eutectic salt, LiF-NaF-KF: 46.5-11.5-42 mol % (commonly referred to as FLiNaK), as well as a molten chloride near eutectic salt, KCl-MgCl2: 68-32 mol %. Several high temperature alloys: Hastelloy-N, Hastelloy-X, Haynes-230, Inconel-617, and Incoloy-800H, Nb-1Zr, a nearly pure Ni alloy Ni-201, and a C/SiSiC ceramic were exposed to molten FLiNaK at 850°C for 500 h in sealed graphite crucibles under an argon cover gas. Corrosion occurred predominantly from dealloying of Cr from the Cr bearing alloys, an effect that was particularly pronounced at the grain boundaries. Corrosion was noted to occur from selective attack of the Si phase in the C/SiSiC ceramic. Alloy weight-loss/area due to molten fluoride salt exposure correlated with the initial Cr-content of the alloys, and was consistent with the Cr-content measured in the salts after corrosion tests. The alloys' weight-loss/area was also found to correlate to the concentration of carbon present in the nominally 20% Cr containing alloys, due to the formation of chromium carbide phases at the grain boundaries. The corrosion mechanisms for the chloride based salt were found to be similar to those observed in FLiNaK, but the chemical attack was found to be less aggressive. Sulfamate Ni electroplating and Mo plasma spraying of Fe-Ni-Cr alloy coupons was investigated to mitigate Cr dissolution. A chemical vapor deposited pyrolytic carbon and SiC coating was also investigated to protect the C/SiSiC composites. Results indicate that Ni-plating has the potential to provide protection against alloy corrosion in molten fluoride salts. Furthermore, the presence of a chromium-oxide interlayer at the interface of the Ni-plating and alloy substrate can further improve the efficacy of the Ni-plating. The pyrolytic carbon and SiC coating on the C/SiSiC composites
Filter for third order phase locked loops
NASA Technical Reports Server (NTRS)
Crow, R. B.; Tausworthe, R. C. (Inventor)
1973-01-01
Filters for third-order phase-locked loops are used in receivers to acquire and track carrier signals, particularly signals subject to high doppler-rate changes in frequency. A loop filter with an open-loop transfer function and set of loop constants, setting the damping factor equal to unity are provided.
NASA Technical Reports Server (NTRS)
Simon, M. K.
1977-01-01
A modification of a Costas loop is described, and the false lock behavior of this system is studied. The modified Costas loop hard limits the output of the in-phase channel, replaces the analog multiplier with a chopper-type device, and is equipped with single-pole arm filters in the loop. The false lock behavior associated with the use of Manchester coded data is investigated; the results can be applied to the assessment of the false lock margin on the Ku-band uplink to the Space Shuttle Orbiter through the TURSS.
Electrolyte salts for nonaqueous electrolytes
Amine, Khalil; Zhang, Zhengcheng; Chen, Zonghai
2012-10-09
Metal complex salts may be used in lithium ion batteries. Such metal complex salts not only perform as an electrolyte salt in a lithium ion batteries with high solubility and conductivity, but also can act as redox shuttles that provide overcharge protection of individual cells in a battery pack and/or as electrolyte additives to provide other mechanisms to provide overcharge protection to lithium ion batteries. The metal complex salts have at least one aromatic ring. The aromatic moiety may be reversibly oxidized/reduced at a potential slightly higher than the working potential of the positive electrode in the lithium ion battery. The metal complex salts may also be known as overcharge protection salts.
ADR salt pill design and crystal growth process for hydrated magnetic salts
NASA Technical Reports Server (NTRS)
Shirron, Peter J. (Inventor); DiPirro, Michael J. (Inventor); Canavan, Edgar R. (Inventor)
2013-01-01
A process is provided for producing a salt pill for use in very low temperature adiabatic demagnetization refrigerators (ADRs). The method can include providing a thermal bus in a housing. The thermal bus can include an array of thermally conductive metal conductors. A hydrated salt can be grown on the array of thermally conductive metal conductors. Thermal conductance can be provided to the hydrated salt.
Wilson loop from a Dyson equation
DOE Office of Scientific and Technical Information (OSTI.GOV)
Pak, M.; Reinhardt, H.
2009-12-15
The Dyson equation proposed for planar temporal Wilson loops in the context of supersymmetric gauge theories is critically analyzed thereby exhibiting its ingredients and approximations involved. We reveal its limitations and identify its range of applicability in nonsupersymmetric gauge theories. In particular, we show that this equation is applicable only to strongly asymmetric planar Wilson loops (consisting of a long and a short pair of loop segments) and as a consequence the Wilsonian potential can be extracted only up to intermediate distances. By this equation the Wilson loop is exclusively determined by the gluon propagator. We solve the Dyson equationmore » in Coulomb gauge for the temporal Wilson loop with the instantaneous part of the gluon propagator and for the spatial Wilson loop with the static gluon propagator obtained in the Hamiltonian approach to continuum Yang-Mills theory and on the lattice. In both cases we find a linearly rising color potential.« less
Pathophysiology of salt sensitivity hypertension.
Ando, Katsuyuki; Fujita, Toshiro
2012-06-01
Dietary salt intake is the most important factor contributing to hypertension, but the salt susceptibility of blood pressure (BP) is different in individual subjects. Although the pathogenesis of salt-sensitive hypertension is heterogeneous, it is mainly attributable to an impaired renal capacity to excrete sodium (Na(+) ). We recently identified two novel mechanisms that impair renal Na(+) -excreting function and result in an increase in BP. First, mineralocorticoid receptor (MR) activation in the kidney, which facilitates distal Na(+) reabsorption through epithelial Na(+) channel activation, causes salt-sensitive hypertension. This mechanism exists not only in models of high-aldosterone hypertension as seen in conditions of obesity or metabolic syndrome, but also in normal- or low-aldosterone type of salt-sensitive hypertension. In the latter, Rac1 activation by salt excess causes MR stimulation. Second, renospecific sympathoactivation may cause an increase in BP under conditions of salt excess. Renal beta2 adrenoceptor stimulation in the kidney leads to decreased transcription of the gene encoding WNK4, a negative regulator of Na(+) reabsorption through Na(+) -Cl (-) cotransporter in the distal convoluted tubules, resulting in salt-dependent hypertension. Abnormalities identified in these two pathways of Na(+) reabsorption in the distal nephron may present therapeutic targets for the treatment of salt-sensitive hypertension.
OMI observations of bromine monoxide emissions from salt lakes
NASA Astrophysics Data System (ADS)
Suleiman, R. M.; Chance, K.; Liu, X.; Gonzalez Abad, G.; Kurosu, T. P.
2015-12-01
In this study, we analyze bromine monoxide (BrO) data from the Ozone Monitoring Instrument (OMI) over various salt lakes. We used OMI data from 2005 to 2014 to investigate BrO signatures from salt lakes. The salt lakes regions we cover include Dead Sea; Salt Lake City, US; Salar de Uyuni, Bolivia; and Namtso, Tibet. Elevated signatures of BrO was found in July and August BrO monthly averages over the Dead Sea. Similar results were found in the BrO monthly averages for August 2006 for the Bolivian Salt Flats. We present a detailed description of the retrieval algorithm for the OMI operational bromine monoxide (BrO) product. The algorithm is based on direct fitting of radiances from 319.0-347.5 nm, within the UV-2 channel of OMI. Radiances are modeled from the solar irradiance, attenuated by contributions from the target gas and interfering gases, rotational Raman scattering, additive and multiplicative closure polynomials and a common mode spectrum. The common mode spectra (one per cross-track position, computed on-line) are the average of several hundred fitting residuals. They include any instrument effects that are unrelated to molecular scattering and absorption cross sections. The BrO retrieval uses albedo- and wavelength-dependent air mass factors (AMFs), which have been pre-computed using climatological BrO profiles. The wavelength-dependent AMF is applied pre-fit to the BrO cross-sections so that vertical column densities are retrieved directly. We validate OMI BrO with ground-based measurements from three stations (Harestua, Lauder, and Barrow) and with chemical transport model simulations. We analyze the global distribution and seasonal variation of BrO and investigate BrO emissions from volcanoes and salt lakes.
NASA Technical Reports Server (NTRS)
Tranquille, C.; Sanderson, T. R.; Marsden, R. G.; Wenzel, K.-P.; Smith, E. J.
1987-01-01
Correlated particle and magnetic field measurements by the ISEE 3 spacecraft are presented for the loop structure behind the interplanetary traveling shock event of Nov. 12, 1978. Following the passage of the turbulent shock region, strong bidirectional streaming of low-energy protons is observed for approximately 6 hours, corresponding to a loop thickness of about 0.07 AU. This region is also characterized by a low relative variance of the magnetic field, a depressed proton intensity, and a reduction in the magnetic power spectral density. Using quasi-linear theory applied to a slab model, a value of 3 AU is derived for the mean free path during the passage of the closed loop. It is inferred from this observation that the proton regime associated with the loop structure is experiencing scatter-free transport and that either the length of the loop is approximately 3 AU between the sun and the earth or else the protons are being reflected at both ends of a smaller loop.
An automatic frequency control loop using overlapping DFTs (Discrete Fourier Transforms)
NASA Technical Reports Server (NTRS)
Aguirre, S.
1988-01-01
An automatic frequency control (AFC) loop is introduced and analyzed in detail. The new scheme is a generalization of the well known Cross Product AFC loop that uses running overlapping discrete Fourier transforms (DFTs) to create a discriminator curve. Linear analysis is included and supported with computer simulations. The algorithm is tested in a low carrier to noise ratio (CNR) dynamic environment, and the probability of loss of lock is estimated via computer simulations. The algorithm discussed is a suboptimum tracking scheme with a larger frequency error variance compared to an optimum strategy, but offers simplicity of implementation and a very low operating threshold CNR. This technique can be applied during the carrier acquisition and re-acquisition process in the Advanced Receiver.
Evaluating four-loop conformal Feynman integrals by D-dimensional differential equations
NASA Astrophysics Data System (ADS)
Eden, Burkhard; Smirnov, Vladimir A.
2016-10-01
We evaluate a four-loop conformal integral, i.e. an integral over four four-dimensional coordinates, by turning to its dimensionally regularized version and applying differential equations for the set of the corresponding 213 master integrals. To solve these linear differential equations we follow the strategy suggested by Henn and switch to a uniformly transcendental basis of master integrals. We find a solution to these equations up to weight eight in terms of multiple polylogarithms. Further, we present an analytical result for the given four-loop conformal integral considered in four-dimensional space-time in terms of single-valued harmonic polylogarithms. As a by-product, we obtain analytical results for all the other 212 master integrals within dimensional regularization, i.e. considered in D dimensions.
Effects of Ethylene on Seed Germination of Halophyte Plants Under Salt Stress.
Li, Weiqiang; Tran, Lam-Son Phan
2017-01-01
Halophyte plant species are those that can finish their life cycle in the presence of 50% or more seawater concentration. Ethylene, as a natural plant hormone produced at later stages of seed germination, plays an important role in regulating seed germination. However, its regulatory role in seed dormancy and germination of halophyte plants under salt stress is still not well understood. In this chapter, we describe methods used for applications of two ethylene donors, ethephon and 1-aminocyclopropane-1-carboxylic acid, in studies aimed at examining the effects of ethylene on seed germination of a representative halophyte plant Suaeda salsa under high salinity. Similar approaches can be applied to the study of ethylene and salt interactions in other plant species, when taking into account that salt sensitivities may differ.
Lee, Se Hee; Jung, Ji Young; Jeon, Che Ok
2014-01-01
To investigate the effects of salt concentration on saeu-jeot (salted shrimp) fermentation, four sets of saeu-jeot samples with 20%, 24%, 28%, and 32% salt concentrations were prepared, and the pH, bacterial and archaeal abundances, bacterial communities, and metabolites were monitored during the entire fermentation period. Quantitative PCR showed that Bacteria were much more abundant than Archaea in all saeu-jeot samples, suggesting that bacterial populations play more important roles than archaeal populations even in highly salted samples. Community analysis indicated that Vibrio, Photobacterium, Psychrobacter, Pseudoalteromonas, and Enterovibrio were identified as the initially dominant genera, and the bacterial successions were significantly different depending on the salt concentration. During the early fermentation period, Salinivibrio predominated in the 20% salted samples, whereas Staphylococcus, Halomonas, and Salimicrobium predominated in the 24% salted samples; eventually, Halanaerobium predominated in the 20% and 24% salted samples. The initially dominant genera gradually decreased as the fermentation progressed in the 28% and 32% salted samples, and eventually Salimicrobium became predominant in the 28% salted samples. However, the initially dominant genera still remained until the end of fermentation in the 32% salted samples. Metabolite analysis showed that the amino acid profile and the initial glycerol increase were similar in all saeu-jeot samples regardless of the salt concentration. After 30–80 days of fermentation, the levels of acetate, butyrate, and methylamines in the 20% and 24% salted samples increased with the growth of Halanaerobium, even though the amino acid concentrations steadily increased until approximately 80–107 days of fermentation. This study suggests that a range of 24–28% salt concentration in saeu-jeot fermentation is appropriate for the production of safe and tasty saeu-jeot. PMID:24587230
Effect of Salted Ice Bags on Surface and Intramuscular Tissue Cooling and Rewarming Rates.
Hunter, Eric J; Ostrowski, Jennifer; Donahue, Matthew; Crowley, Caitlyn; Herzog, Valerie
2016-02-01
Many researchers have investigated the effectiveness of different cryotherapy agents at decreasing intramuscular tissue temperatures. However, no one has looked at the effectiveness of adding salt to an ice bag. To compare the cooling effectiveness of different ice bags (wetted, salted cubed, and salted crushed) on cutaneous and intramuscular temperatures. Repeated-measures counterbalanced design. University research laboratory. 24 healthy participants (13 men, 11 women; age 22.46 ± 2.33 y, height 173.25 ± 9.78 cm, mass 74.51 ± 17.32 kg, subcutaneous thickness 0.63 ± 0.27 cm) with no lower-leg injuries, vascular diseases, sensitivity to cold, compromised circulation, or chronic use of NSAIDs. Ice bags made of wetted ice (2000 mL ice and 300 mL water), salted cubed ice (intervention A; 2000 mL of cubed ice and 1/2 tablespoon of salt), and salted crushed ice (intervention B; 2000 mL of crushed ice and 1/2 tablespoon of salt) were applied to the posterior gastrocnemius for 30 min. Each participant received all conditions with at least 4 d between treatments. Cutaneous and intramuscular (2 cm plus adipose thickness) temperatures of nondominant gastrocnemius were measured during a 10-min baseline period, a 30-min treatment period, and a 45-min rewarming period. Differences from baseline were observed for all treatments. The wetted-ice and salted-cubed-ice bags produced significantly lower intramuscular temperatures than the salted-crushed-ice bag. Wetted-ice bags produced the greatest temperature change for cutaneous tissues. Wetted- and salted-cubed-ice bags were equally effective at decreasing intramuscular temperature at 2 cm subadipose. Clinical practicality may favor salted-ice bags over wetted-ice bags.
DNA looping by FokI: the impact of twisting and bending rigidity on protein-induced looping dynamics
Laurens, Niels; Rusling, David A.; Pernstich, Christian; Brouwer, Ineke; Halford, Stephen E.; Wuite, Gijs J. L.
2012-01-01
Protein-induced DNA looping is crucial for many genetic processes such as transcription, gene regulation and DNA replication. Here, we use tethered-particle motion to examine the impact of DNA bending and twisting rigidity on loop capture and release, using the restriction endonuclease FokI as a test system. To cleave DNA efficiently, FokI bridges two copies of an asymmetric sequence, invariably aligning the sites in parallel. On account of the fixed alignment, the topology of the DNA loop is set by the orientation of the sites along the DNA. We show that both the separation of the FokI sites and their orientation, altering, respectively, the twisting and the bending of the DNA needed to juxtapose the sites, have profound effects on the dynamics of the looping interaction. Surprisingly, the presence of a nick within the loop does not affect the observed rigidity of the DNA. In contrast, the introduction of a 4-nt gap fully relaxes all of the torque present in the system but does not necessarily enhance loop stability. FokI therefore employs torque to stabilise its DNA-looping interaction by acting as a ‘torsional’ catch bond. PMID:22373924
NASA Astrophysics Data System (ADS)
Warsitzka, Michael; Kukowski, Nina; Kley, Jonas
2017-04-01
In extensional sedimentary basins, the movement of ductile salt is mainly controlled by the vertical displacement of the salt layer, differential loading due to syn-kinematic deposition, and tectonic shearing at the top and the base of the salt layer. During basement normal faulting, salt either tends to flow downward to the basin centre driven by its own weight or it is squeezed upward due to differential loading. In analogue experiments and analytical models, we address the interplay between normal faulting of the sub-salt basement, compaction and density inversion of the supra-salt cover and the kinematic response of the ductile salt layer. The analogue experiments consist of a ductile substratum (silicone putty) beneath a denser cover layer (sand mixture). Both layers are displaced by normal faults mimicked through a downward moving block within the rigid base of the experimental apparatus and the resulting flow patterns in the ductile layer are monitored and analysed. In the computational models using an analytical approximative solution of the Navier-Stokes equation, the steady-state flow velocity in an idealized natural salt layer is calculated in order to evaluate how flow patterns observed in the analogue experiments can be translated to nature. The analytical calculations provide estimations of the prevailing direction and velocity of salt flow above a sub-salt normal fault. The results of both modelling approaches show that under most geological conditions salt moves downwards to the hanging wall side as long as vertical offset and compaction of the cover layer are small. As soon as an effective average density of the cover is exceeded, the direction of the flow velocity reverses and the viscous material is squeezed towards the elevated footwall side. The analytical models reveal that upward flow occurs even if the average density of the overburden does not exceed the density of salt. By testing various scenarios with different layer thicknesses
DOT National Transportation Integrated Search
2013-03-01
This research developed and completed a field evaluation of salt distribution equipment. The evaluation provides a direct comparison of three different types of salt spreaders at three different truck speeds and brine rates. A rubber mat was divided ...
Leonardi, Nicoletta; Ganju, Neil K.; Fagherazzi, Sergio
2016-01-01
Salt marsh losses have been documented worldwide because of land use change, wave erosion, and sea-level rise. It is still unclear how resistant salt marshes are to extreme storms and whether they can survive multiple events without collapsing. Based on a large dataset of salt marsh lateral erosion rates collected around the world, here, we determine the general response of salt marsh boundaries to wave action under normal and extreme weather conditions. As wave energy increases, salt marsh response to wind waves remains linear, and there is not a critical threshold in wave energy above which salt marsh erosion drastically accelerates. We apply our general formulation for salt marsh erosion to historical wave climates at eight salt marsh locations affected by hurricanes in the United States. Based on the analysis of two decades of data, we find that violent storms and hurricanes contribute less than 1% to long-term salt marsh erosion rates. In contrast, moderate storms with a return period of 2.5 mo are those causing the most salt marsh deterioration. Therefore, salt marshes seem more susceptible to variations in mean wave energy rather than changes in the extremes. The intrinsic resistance of salt marshes to violent storms and their predictable erosion rates during moderate events should be taken into account by coastal managers in restoration projects and risk management plans. PMID:26699461
Leonardi, Nicoletta; Ganju, Neil K.; Fagherazzi, Sergio
2016-01-01
Salt marsh losses have been documented worldwide because of land use change, wave erosion, and sea-level rise. It is still unclear how resistant salt marshes are to extreme storms and whether they can survive multiple events without collapsing. Based on a large dataset of salt marsh lateral erosion rates collected around the world, here, we determine the general response of salt marsh boundaries to wave action under normal and extreme weather conditions. As wave energy increases, salt marsh response to wind waves remains linear, and there is not a critical threshold in wave energy above which salt marsh erosion drastically accelerates. We apply our general formulation for salt marsh erosion to historical wave climates at eight salt marsh locations affected by hurricanes in the United States. Based on the analysis of two decades of data, we find that violent storms and hurricanes contribute less than 1% to long-term salt marsh erosion rates. In contrast, moderate storms with a return period of 2.5 mo are those causing the most salt marsh deterioration. Therefore, salt marshes seem more susceptible to variations in mean wave energy rather than changes in the extremes. The intrinsic resistance of salt marshes to violent storms and their predictable erosion rates during moderate events should be taken into account by coastal managers in restoration projects and risk management plans.
Leonardi, Nicoletta; Ganju, Neil K; Fagherazzi, Sergio
2016-01-05
Salt marsh losses have been documented worldwide because of land use change, wave erosion, and sea-level rise. It is still unclear how resistant salt marshes are to extreme storms and whether they can survive multiple events without collapsing. Based on a large dataset of salt marsh lateral erosion rates collected around the world, here, we determine the general response of salt marsh boundaries to wave action under normal and extreme weather conditions. As wave energy increases, salt marsh response to wind waves remains linear, and there is not a critical threshold in wave energy above which salt marsh erosion drastically accelerates. We apply our general formulation for salt marsh erosion to historical wave climates at eight salt marsh locations affected by hurricanes in the United States. Based on the analysis of two decades of data, we find that violent storms and hurricanes contribute less than 1% to long-term salt marsh erosion rates. In contrast, moderate storms with a return period of 2.5 mo are those causing the most salt marsh deterioration. Therefore, salt marshes seem more susceptible to variations in mean wave energy rather than changes in the extremes. The intrinsic resistance of salt marshes to violent storms and their predictable erosion rates during moderate events should be taken into account by coastal managers in restoration projects and risk management plans.
Investigation of residual anode material after electrorefining uranium in molten chloride salt
NASA Astrophysics Data System (ADS)
Rose, M. A.; Williamson, M. A.; Willit, J.
2015-12-01
A buildup of material at uranium anodes during uranium electrorefining in molten chloride salts has been observed. Potentiodynamic testing has been conducted using a three electrode cell, with a uranium working electrode in both LiCl/KCl eutectic and LiCl each containing ∼5 mol% UCl3. The anodic current response was observed at 50° intervals between 450 °C and 650 °C in the eutectic salt. These tests revealed a buildup of material at the anode in LiCl/KCl salt, which was sampled at room temperature, and analyzed using ICP-MS, XRD and SEM techniques. Examination of the analytical data, current response curves and published phase diagrams has established that as the uranium anode dissolves, the U3+ ion concentration in the diffusion layer surrounding the electrode rises precipitously to levels, which may at low temperatures exceed the solubility limit for UCl3 or in the case of the eutectic salt for K2UCl5. The reduction in current response observed at low temperature in eutectic salt is eliminated at 650 °C, where K2UCl5 is absent due to its congruent melting and only simple concentration polarization effects are seen. In LiCl similar concentration effects are seen though significantly longer time at applied potential is required to effect a reduction in the current response as compared to the eutectic salt.
Resistance of Nanostructured Environmental Barrier Coatings to the Movement of Molten Salts
NASA Astrophysics Data System (ADS)
Rao, S.; Frederick, L.; McDonald, A.
2012-09-01
Corrosion of components in a recovery boiler is a major problem faced by the pulp and paper industry. The superheater tubes become severely corroded due to the presence of sulfidic gases in the boiler and molten salts which are deposited on the surface of the tubes. As a result, the boiler must be decommissioned for expensive maintenance and repairs. Yttria-stabilized zirconia (YSZ) coatings have been shown to provide corrosion resistance when applied on gas turbines operating at high temperatures. Air plasma-sprayed YSZ environmental barrier coatings on Type 309 stainless steel were exposed to three different corrosive environments: Test A—600 °C, salt vapors, flue gases, 168 h; Test B—600 °C, molten salt, air, 168 h; and Test C—600 °C, molten salt, flue gases, 168 h. Two different types of YSZ coatings—conventional YSZ and nanostructured YSZ—were tested to study their resistance to corrosion and molten salt penetration. The performances of both types of coatings were evaluated, and a comparative study was conducted. It was found that the nanostructured YSZ samples protected the stainless steel substrate better than their conventional counterparts. This superior performance was attributed to the presence of semi-molten nano-agglomerates present in the coating microstructure, which acted as collection points for the penetrating molten salts.
Smallwood, R. A.; Lester, R.; Piasecki, G. J.; Klein, P. D.; Greco, R.; Jackson, B. T.
1972-01-01
Bile salt metabolism was studied in fetal dogs 1 wk before term. The size and distribution of the fetal bile salt pool were measured, and individual bile salts were identified. The hepatic excretion of endogenous bile salts was studied in bile fistula fetuses, and the capacity of this excretory mechanism was investigated by the i.v. infusion of a load of sodium taurocholate-14C up to 20 times the endogenous pool size. The total fetal bile salt pool was 30.9±2.7 μmoles, of which two-thirds was in the fetal gallbladder. Expressed on a body weight basis, this was equal to approximately one-half the estimated pool size in the adult dog (119.2±11.3 vs. 247.5±33.1 μmoles/kg body wt). Measurable quantities of bile salt were found in small bowel (6.0±1.8 μmoles), large bowel (1.1±0.3 μmoles), liver (1.2±0.5 μmoles), and plasma (0.1±0.03 μmoles). Plasma bile salt levels were significantly greater in fetal than in maternal plasma (1.01±0.24 μg/ml vs. 0.36±0.06 μg/ml; P < 0.05). Fetal hepatic bile salt excretion showed a fall over the period of study from 2.04±0.34 to 0.30±0.07 μmoles/hr. The maximal endogenous bile salt concentration in fetal hepatic bile was 18.7±1.5 μmoles/ml. The concentration in fetal gallbladder bile was 73.9±8.6 μmoles/ml; and, in those studies in which hepatic and gallbladder bile could be compared directly, the gallbladder appeared to concentrate bile four- to fivefold. Taurocholate, taurochenodeoxycholate, and taurodeoxycholate were present in fetal bile, but no free bile salts were identified. The presence of deoxycholate was confirmed by thin-layer chromatography and gas liquid chromatography, and the absence of microorganisms in fetal gut suggests that it was probably transferred from the maternal circulation. After infusion of a taurocholate load, fetal hepatic bile salt excretion increased 30-fold, so that 85-95% of the dose was excreted by the fetal liver during the period of observation. Placental transfer accounted
NASA Technical Reports Server (NTRS)
Rector, Tony; Peyton, Barbara M.; Steele, John W.; Makinen, Janice; Bue, Grant C.; Campbell, Colin
2014-01-01
Water loop maintenance components to maintain the water quality of the Advanced Spacesuit Water Membrane Evaporation (SWME) water recirculation loop have undergone a comparative performance evaluation with a second SWME water recirculation loop with no water quality maintenance. Results show the benefits of periodic water maintenance. The SWME is a heat rejection device under development at the NASA Johnson Space Center to perform thermal control for advanced spacesuits. One advantage to this technology is the potential for a significantly greater degree of tolerance to contamination when compared to the existing Sublimator technology. The driver for the evaluation of water recirculation maintenance components was to further enhance this advantage through the leveraging of fluid loop management lessons learned from the International Space Station (ISS). A bed design that was developed for a UTAS military application, and considered for a potential ISS application with the Urine Processor Assembly, provided a low pressure drop means for water maintenance in a recirculation loop. The bed design is coupled with high capacity ion exchange resins, organic adsorbents, and a cyclic methodology developed for the Extravehicular Mobility Unit (EMU) Transport Water loop. The maintenance cycle included the use of a biocide delivery component developed for ISS to introduce a biocide in a microgravity compatible manner for the Internal Active Thermal Control System (IATCS). The leveraging of these water maintenance technologies to the SWME recirculation loop is a unique demonstration of applying the valuable lessons learned on the ISS to the next generation of manned spaceflight Environmental Control and Life Support System (ECLSS) hardware.
NASA Technical Reports Server (NTRS)
Rector, Tony; Peyton, Barbara M.; Steele, John W.; Makinen, Janice; Bue, Grant C.; Campbell, Colin
2014-01-01
Water loop maintenance components to maintain the water quality of the Advanced Spacesuit Water Membrane Evaporation (SWME) water recirculation loop have undergone a comparative performance evaluation with a recirculating control loop which had no water quality maintenance. Results show that periodic water maintenance can improve performance of the SWME. The SWME is a heat rejection device under development at the NASA Johnson Space Center to perform thermal control for advanced spacesuits. One advantage of this technology is the potential for a significantly greater degree of tolerance to contamination when compared to the existing sublimator technology. The driver for the evaluation of water recirculation maintenance components was to enhance the robustness of the SWME through the leveraging of fluid loop management lessons learned from the International Space Station (ISS). A patented bed design that was developed for a United Technologies Aerospace System military application provided a low pressure drop means for water maintenance in the SWME recirculation loop. The bed design is coupled with high capacity ion exchange resins, organic adsorbents, and a cyclic methodology developed for the Extravehicular Mobility Unit (EMU) Transport Water loop. The maintenance cycle included the use of a biocide delivery component developed for the ISS to introduce a biocide in a microgravity compatible manner for the Internal Active Thermal Control System (IATCS). The leveraging of these water maintenance technologies to the SWME recirculation loop is a unique demonstration of applying the valuable lessons learned on the ISS to the next generation of manned spaceflight Environmental Control and Life Support System (ECLSS) hardware.
NASA Technical Reports Server (NTRS)
Rector, Tony; Peyton, Barbara; Steele, John W.; Bue, Grant C.; Campbell, Colin; Makinen, Janice
2014-01-01
Water loop maintenance components to maintain the water quality of the Advanced Spacesuit Water Membrane Evaporation (SWME) water recirculation loop have undergone a comparative performance evaluation with a second SWME water recirculation loop with no water quality maintenance. Results show the benefits of periodic water maintenance. The SWME is a heat rejection device under development at the NASA Johnson Space Center to perform thermal control for advanced spacesuits. One advantage to this technology is the potential for a significantly greater degree of tolerance to contamination when compared to the existing Sublimator technology. The driver for the evaluation of water recirculation maintenance components was to further enhance this advantage through the leveraging of fluid loop management lessonslearned from the International Space Station (ISS). A bed design that was developed for a UTAS military application, and considered for a potential ISS application with the Urine Processor Assembly, provided a low pressure drop means for water maintenance in a recirculation loop. The bed design is coupled with high capacity ion exchange resins, organic adsorbents, and a cyclic methodology developed for the Extravehicular Mobility Unit (EMU) Transport Water loop. The maintenance cycle included the use of a biocide delivery component developed for ISS to introduce a biocide in a microgravity-compatible manner for the Internal Active Thermal Control System (IATCS). The leveraging of these water maintenance technologies to the SWME recirculation loop is a unique demonstration of applying the valuable lessons learned on the ISS to the next generation of manned spaceflight Environmental Control and Life Support System (ECLSS) hardware.
Feasibility of overnight closed-loop control based on hourly blood glucose measurements.
Patte, Caroline; Pleus, Stefan; Galley, Paul; Weinert, Stefan; Haug, Cornelia; Freckmann, Guido
2012-07-01
Safe and effective closed-loop control (artificial pancreas) is the ultimate goal of insulin delivery. In this study, we examined the performance of a closed-loop control algorithm used for the overnight time period to safely achieve a narrow target range of blood glucose (BG) concentrations prior to breakfast. The primary goal was to compare the quality of algorithm control during repeated overnight experiments. Twenty-three subjects with type 1 diabetes performed 2 overnight experiments on each of three visits at the study site, resulting in 138 overnight experiments. On the first evening, the subject's insulin therapy was applied; on the second, the insulin was delivered by an algorithm based on subcutaneous continuous glucose measurements (including meal control) until midnight. Overnight closed-loop control was applied between midnight and 6 a.m. based on hourly venous BG measurements during the first and second nights. The number of BG values within the target range (90-150 mg/dl) increased from 52.9% (219 out of 414 measurements) during the first nights to 72.2% (299 out of 414 measurements) during the second nights (p < .001, χ²-test). The occurrence of hypoglycemia interventions was reduced from 14 oral glucose interventions, the latest occurring at 2:36 a.m. during the first nights, to 1 intervention occurring at 1:02 a.m. during the second nights (p < .001, χ²-test). Overnight controller performance improved when optimized initial control was given; this was suggested by the better metabolic control during the second night. Adequate controller run-in time seems to be important for achieving good overnight control. In addition, the findings demonstrate that hourly BG data are sufficient for the closed-loop control algorithm tested to achieve appropriate glycemic control. © 2012 Diabetes Technology Society.
Identification and characterization of salt responsive miRNA-SSR markers in rice (Oryza sativa).
Mondal, Tapan Kumar; Ganie, Showkat Ahmad
2014-02-10
Salinity is an important abiotic stress that affects agricultural production and productivity. It is a complex trait that is regulated by different molecular mechanisms. miRNAs are non-coding RNAs which are highly conserved and regulate gene expression. Simple sequence repeats (SSRs) are robust molecular markers for studying genetic diversity. Although several SSR markers are available now, challenge remains to identify the trait-specific SSRs which can be used for marker assisted breeding. In order to understand the genetic diversity of salt responsive-miRNA genes in rice, SSR markers were mined from 130 members of salt-responsive miRNA genes of rice and validated among the contrasting panels of tolerant as well as susceptible rice genotypes, each with 12 genotypes. Although 12 miR-SSRs were found to be polymorphic, only miR172b-SSR was able to differentiate the tolerant and susceptible genotypes in 2 different groups. It had also been found that miRNA genes were more diverse in susceptible genotypes than the tolerant one (as indicated by polymorphic index content) which might interfere to form the stem-loop structure of premature miRNA and their subsequent synthesis in susceptible genotypes. Thus, we concluded that length variations of the repeats in salt responsive miRNA genes may be responsible for a possible sensitivity to salinity adaptation. This is the first report of characterization of trait specific miRNA derived SSRs in plants. Copyright © 2013 Elsevier B.V. All rights reserved.
Warner, Benjamin P.
2003-06-24
The present invention provides a method for detecting ionizing radiation. Exposure of silver salt AgX to ionizing radiation results in the partial reduction of the salt to a mixture of silver salt and silver metal. The mixture is further reduced by a reducing agent, which causes the production of acid (HX) and the oxidized form of the reducing agent (R). Detection of HX indicates that the silver salt has been exposed to ionizing radiation. The oxidized form of the reducing agent (R) may also be detected. The invention also includes dosimeters employing the above method for detecting ionizing radiation.
Melse-Boonstra, A; Rozendaal, M; Rexwinkel, H; Gerichhausen, M J; van den Briel, T; Bulux, J; Solomons, N W; West, C E
1998-09-01
The use of discretionary salt, which is salt added during cooking and at the table, as a suitable vehicle for iodine intake was assessed by measuring salt consumption using the lithium-marker technique in rural areas of Guatemala and Benin. In both countries, we studied boys aged 6-12 y and their mothers. Subjects used lithium-labeled salt after all unlabeled salt was removed from their households. In Guatemala, 24-h urine samples for 9 mother-son pairs were collected at baseline and on days 7, 8, and 9 during the use of lithium-labeled salt. Total maternal salt intake averaged 5.2 +/- 1.7 g/d (mean +/- SD), of which 77 +/- 24% came from discretionary sources, whereas Guatemalan boys consumed 1.8 +/- 0.6 g salt/d, of which 72 +/- 12% came from discretionary sources. In Benin, urine collection from 13 mother-son pairs took place at baseline and on days 5 and 7. Beninese mothers had a total salt intake of 9.0 +/- 2.9 g/d and their sons had an intake of 5.7 +/- 2.8 g/d; discretionary salt contributed 52 +/- 14% and 50 +/- 13%, respectively, of total salt consumed. Therefore, fortification of household salt appears to be an appropriate method of controlling iodine deficiency in both countries, although fortification of other salt sources could be considered in Benin.
Polyakov loop modeling for hot QCD
DOE Office of Scientific and Technical Information (OSTI.GOV)
Fukushima, Kenji; Skokov, Vladimir
Here, we review theoretical aspects of quantum chromodynamics (QCD) at finite temperature. The most important physical variable to characterize hot QCD is the Polyakov loop, which is an approximate order parameter for quark deconfinement in a hot gluonic medium. Additionally to its role as an order parameter, the Polyakov loop has rich physical contents in both perturbative and non-perturbative sectors. This review covers a wide range of subjects associated with the Polyakov loop from topological defects in hot QCD to model building with coupling to the Polyakov loop.
Capillary-Condenser-Pumped Heat-Transfer Loop
NASA Technical Reports Server (NTRS)
Silverstein, Calvin C.
1989-01-01
Heat being transferred supplies operating power. Capillary-condenser-pumped heat-transfer loop similar to heat pipe and to capillary-evaporator-pumped heat-transfer loop in that heat-transfer fluid pumped by evaporation and condensation of fluid at heat source and sink, respectively. Capillary condenser pump combined with capillary evaporator pump to form heat exchanger circulating heat-transfer fluids in both loops. Transport of heat more nearly isothermal. Thermal stress in loop reduced, and less external surface area needed in condenser section for rejection of heat to heat sink.
Polyakov loop modeling for hot QCD
Fukushima, Kenji; Skokov, Vladimir
2017-06-19
Here, we review theoretical aspects of quantum chromodynamics (QCD) at finite temperature. The most important physical variable to characterize hot QCD is the Polyakov loop, which is an approximate order parameter for quark deconfinement in a hot gluonic medium. Additionally to its role as an order parameter, the Polyakov loop has rich physical contents in both perturbative and non-perturbative sectors. This review covers a wide range of subjects associated with the Polyakov loop from topological defects in hot QCD to model building with coupling to the Polyakov loop.
Kalman Orbit Optimized Loop Tracking
NASA Technical Reports Server (NTRS)
Young, Lawrence E.; Meehan, Thomas K.
2011-01-01
Under certain conditions of low signal power and/or high noise, there is insufficient signal to noise ratio (SNR) to close tracking loops with individual signals on orbiting Global Navigation Satellite System (GNSS) receivers. In addition, the processing power available from flight computers is not great enough to implement a conventional ultra-tight coupling tracking loop. This work provides a method to track GNSS signals at very low SNR without the penalty of requiring very high processor throughput to calculate the loop parameters. The Kalman Orbit-Optimized Loop (KOOL) tracking approach constitutes a filter with a dynamic model and using the aggregate of information from all tracked GNSS signals to close the tracking loop for each signal. For applications where there is not a good dynamic model, such as very low orbits where atmospheric drag models may not be adequate to achieve the required accuracy, aiding from an IMU (inertial measurement unit) or other sensor will be added. The KOOL approach is based on research JPL has done to allow signal recovery from weak and scintillating signals observed during the use of GPS signals for limb sounding of the Earth s atmosphere. That approach uses the onboard PVT (position, velocity, time) solution to generate predictions for the range, range rate, and acceleration of the low-SNR signal. The low- SNR signal data are captured by a directed open loop. KOOL builds on the previous open loop tracking by including feedback and observable generation from the weak-signal channels so that the MSR receiver will continue to track and provide PVT, range, and Doppler data, even when all channels have low SNR.
Parallel Digital Phase-Locked Loops
NASA Technical Reports Server (NTRS)
Sadr, Ramin; Shah, Biren N.; Hinedi, Sami M.
1995-01-01
Wide-band microwave receivers of proposed type include digital phase-locked loops in which band-pass filtering and down-conversion of input signals implemented by banks of multirate digital filters operating in parallel. Called "parallel digital phase-locked loops" to distinguish them from other digital phase-locked loops. Systems conceived as cost-effective solution to problem of filtering signals at high sampling rates needed to accommodate wide input frequency bands. Each of M filters process 1/M of spectrum of signal.
Dietary Salt Intake and Hypertension
2014-01-01
Over the past century, salt has been the subject of intense scientific research related to blood pressure elevation and cardiovascular mortalities. Moderate reduction of dietary salt intake is generally an effective measure to reduce blood pressure. However, recently some in the academic society and lay media dispute the benefits of salt restriction, pointing to inconsistent outcomes noted in some observational studies. A reduction in dietary salt from the current intake of 9-12 g/day to the recommended level of less than 5-6 g/day will have major beneficial effects on cardiovascular health along with major healthcare cost savings around the world. The World Health Organization (WHO) strongly recommended to reduce dietary salt intake as one of the top priority actions to tackle the global non-communicable disease crisis and has urged member nations to take action to reduce population wide dietary salt intake to decrease the number of deaths from hypertension, cardiovascular disease and stroke. However, some scientists still advocate the possibility of increased risk of CVD morbidity and mortality at extremes of low salt intake. Future research may inform the optimal sodium reduction strategies and intake targets for general populations. Until then, we have to continue to build consensus around the greatest benefits of salt reduction for CVD prevention, and dietary salt intake reduction strategies must remain at the top of the public health agenda. PMID:25061468
NASA Astrophysics Data System (ADS)
Sumekar, W.; Al-Baarri, A. N.; Kurnianto, E.
2018-01-01
Marketing distribution is an important of the strategy in business development in agroindustries. The aim of the research was to introduce marketing (distribution pattern, margin and marketing efficiency) at the salted egg agro industries in Brebes Regency. Survey method had been conducted on 52 salted egg agro industries which had active PIRT certificate. The data collection was conducted by means of interview and observation. Descriptive analysis was used to determine the marketing distribution of salted eggs. Marketing efficiency was obtained by calculating marketing margin and farmer share. The results show that the salted egg agro industries implemented two marketing distribution patterns; direct marketing pattern (consumer→producers) and indirect marketing pattern (producer→retailer→consumer). The number of the salted egg agro industries which apply indirect marketing pattern is 57.69%. The implementation of direct and indirect marketing patterns was classified as efficient according to the farmer’s share values of 87.13% and 78.21%. It can be recommended the direct marketing.
Loop Quantization and Symmetry: Configuration Spaces
NASA Astrophysics Data System (ADS)
Fleischhack, Christian
2018-06-01
Given two sets S 1, S 2 and unital C *-algebras A_1, A_2 of functions thereon, we show that a map {σ : {S}_1 \\longrightarrow {S}_2} can be lifted to a continuous map \\barσ : spec A_1 \\longrightarrow spec A_2 iff σ^\\ast A_2 := σ^\\ast f | f \\in A_2 \\subseteq A_1. Moreover, \\bar σ is unique if existing, and injective iff σ^\\ast A_2 is dense. Then, we apply these results to loop quantum gravity and loop quantum cosmology. For all usual technical conventions, we decide whether the cosmological quantum configuration space is embedded into the gravitational one; indeed, both are spectra of some C *-algebras, say, A_cosm and A_grav, respectively. Typically, there is no embedding, but one can always get an embedding by the defining A_cosm := C^\\ast(σ^\\ast A_grav), where {σ} denotes the embedding between the classical configuration spaces. Finally, we explicitly determine {C^\\ast(σ^\\ast A_grav) in the homogeneous isotropic case for A_grav generated by the matrix functions of parallel transports along analytic paths. The cosmological quantum configuration space so equals the disjoint union of R and the Bohr compactification of R, appropriately glued together.
Loop Quantization and Symmetry: Configuration Spaces
NASA Astrophysics Data System (ADS)
Fleischhack, Christian
2018-04-01
Given two sets S 1, S 2 and unital C *-algebras A_1, A_2 of functions thereon, we show that a map σ : S_1 \\longrightarrow S_2 can be lifted to a continuous map \\barσ : spec A_1 \\longrightarrow spec A_2 iff σ^\\ast A_2 := σ^\\ast f | f \\in A_2 \\subseteq A_1. Moreover, \\bar σ is unique if existing, and injective iff {σ^\\ast A_2 is dense. Then, we apply these results to loop quantum gravity and loop quantum cosmology. For all usual technical conventions, we decide whether the cosmological quantum configuration space is embedded into the gravitational one; indeed, both are spectra of some C *-algebras, say, A_cosm and A_grav, respectively. Typically, there is no embedding, but one can always get an embedding by the defining A_cosm := C^\\ast(σ^\\ast A_grav), where σ denotes the embedding between the classical configuration spaces. Finally, we explicitly determine C^\\ast(σ^\\ast A_grav) in the homogeneous isotropic case for A_grav generated by the matrix functions of parallel transports along analytic paths. The cosmological quantum configuration space so equals the disjoint union of R and the Bohr compactification of R , appropriately glued together.
Yang, Zemao; Lu, Ruike; Dai, Zhigang; Yan, An; Tang, Qing; Cheng, Chaohua; Xu, Ying; Yang, Wenting; Su, Jianguang
2017-01-01
High salinity is a major environmental stressor for crops. To understand the regulatory mechanisms underlying salt tolerance, we conducted a comparative transcriptome analysis between salt-tolerant and salt-sensitive jute (Corchorus spp.) genotypes in leaf and root tissues under salt stress and control conditions. In total, 68,961 unigenes were identified. Additionally, 11,100 unigenes (including 385 transcription factors (TFs)) exhibited significant differential expression in salt-tolerant or salt-sensitive genotypes. Numerous common and unique differentially expressed unigenes (DEGs) between the two genotypes were discovered. Fewer DEGs were observed in salt-tolerant jute genotypes whether in root or leaf tissues. These DEGs were involved in various pathways, such as ABA signaling, amino acid metabolism, etc. Among the enriched pathways, plant hormone signal transduction (ko04075) and cysteine/methionine metabolism (ko00270) were the most notable. Eight common DEGs across both tissues and genotypes with similar expression profiles were part of the PYL-ABA-PP2C (pyrabactin resistant-like/regulatory components of ABA receptors-abscisic acid-protein phosphatase 2C). The methionine metabolism pathway was only enriched in salt-tolerant jute root tissue. Twenty-three DEGs were involved in methionine metabolism. Overall, numerous common and unique salt-stress response DEGs and pathways between salt-tolerant and salt-sensitive jute have been discovered, which will provide valuable information regarding salt-stress response mechanisms and help improve salt-resistance molecular breeding in jute. PMID:28927022
Dunford, Elizabeth; Webster, Jacqueline; Woodward, Mark; Czernichow, Sebastien; Yuan, Wen Lun; Jenner, Katharine; Ni Mhurchu, Cliona; Jacobson, Michael; Campbell, Norm; Neal, Bruce
2012-06-12
Several fast food companies have made commitments to reduce the levels of salt in the foods they serve, but technical issues are often cited as a barrier to achieving substantial reductions. Our objective was to examine the reported salt levels for products offered by leading multinational fast food chains. Data on salt content for products served by six fast food chains operating in Australia, Canada, France, New Zealand, the United Kingdom and the United States were collected by survey in April 2010. Mean salt contents (and their ranges) were calculated and compared within and between countries and companies. We saw substantial variation in the mean salt content for different categories of products. For example, the salads we included in our survey contained 0.5 g of salt per 100 g, whereas the chicken products we included contained 1.6 g. We also saw variability between countries: chicken products from the UK contained 1.1 g of salt per 100 g, whereas chicken products from the US contained 1.8 g. Furthermore, the mean salt content of food categories varied between companies and between the same products in different countries (e.g., McDonald's Chicken McNuggets contain 0.6 g of salt per 100 g in the UK, but 1.6 g of salt per 100 g in the US). The salt content of fast foods varies substantially, not only by type of food, but by company and country in which the food is produced. Although the reasons for this variation are not clear, the marked differences in salt content of very similar products suggest that technical reasons are not a primary explanation. In the right regulatory environment, it is likely that fast food companies could substantially reduce the salt in their products, translating to large gains for population health.
Dunford, Elizabeth; Webster, Jacqueline; Woodward, Mark; Czernichow, Sebastien; Yuan, Wen Lun; Jenner, Katharine; Mhurchu, Cliona Ni; Jacobson, Michael; Campbell, Norm; Neal, Bruce
2012-01-01
Background: Several fast food companies have made commitments to reduce the levels of salt in the foods they serve, but technical issues are often cited as a barrier to achieving substantial reductions. Our objective was to examine the reported salt levels for products offered by leading multinational fast food chains. Methods: Data on salt content for products served by six fast food chains operating in Australia, Canada, France, New Zealand, the United Kingdom and the United States were collected by survey in April 2010. Mean salt contents (and their ranges) were calculated and compared within and between countries and companies. Results: We saw substantial variation in the mean salt content for different categories of products. For example, the salads we included in our survey contained 0.5 g of salt per 100 g, whereas the chicken products we included contained 1.6 g. We also saw variability between countries: chicken products from the UK contained 1.1 g of salt per 100 g, whereas chicken products from the US contained 1.8 g. Furthermore, the mean salt content of food categories varied between companies and between the same products in different countries (e.g., McDonald’s Chicken McNuggets contain 0.6 g of salt per 100 g in the UK, but 1.6 g of salt per 100 g in the US). Interpretation: The salt content of fast foods varies substantially, not only by type of food, but by company and country in which the food is produced. Although the reasons for this variation are not clear, the marked differences in salt content of very similar products suggest that technical reasons are not a primary explanation. In the right regulatory environment, it is likely that fast food companies could substantially reduce the salt in their products, translating to large gains for population health. PMID:22508978
NASA Astrophysics Data System (ADS)
Lei, Qiantao; Liu, Ke; Gao, Jie; Li, Xiaolin; Shen, Hao; Li, Yan
2017-08-01
Nickel-based alloys as candidate materials for Thorium Molten Salt Reactor (TMSR), need to be used under high temperature in molten salt environment. In order to ensure the safety of the reactor running, it is necessary to study the elemental move characteristic of nickel-based alloys in the high temperature molten salts. In this work, the scanning nuclear microprobe at Fudan University was applied to study the elemental move. The Nickel-based alloy samples were corroded by molten salt at different temperatures. The element concentrations in the Nickel-based alloys samples were determined by the scanning nuclear microprobe. Micro-PIXE results showed that the element concentrations changed from the interior to the exterior of the alloy samples after the corrosion.
Alternative methods of salt disposal at the seven salt sites for a nuclear waste repository
DOE Office of Scientific and Technical Information (OSTI.GOV)
Not Available
1987-02-01
This study discusses the various alternative salt management techniques for the disposal of excess mined salt at seven potentially acceptable nuclear waste repository sites: Deaf Smith and Swisher Counties, Texas; Richton and Cypress Creek Domes, Mississippi; Vacherie Dome, Louisiana; and Davis and Lavender Canyons, Utah. Because the repository development involves the underground excavation of corridors and waste emplacement rooms, in either bedded or domed salt formations, excess salt will be mined and must be disposed of offsite. The salt disposal alternatives examined for all the sites include commercial use, ocean disposal, deep well injection, landfill disposal, and underground mine disposal.more » These alternatives (and other site-specific disposal methods) are reviewed, using estimated amounts of excavated, backfilled, and excess salt. Methods of transporting the excess salt are discussed, along with possible impacts of each disposal method and potential regulatory requirements. A preferred method of disposal is recommended for each potentially acceptable repository site. 14 refs., 5 tabs.« less
Hashimoto, Tomomi; Takase, Hiroyuki; Okado, Tateo; Sugiura, Tomonori; Yamashita, Sumiyo; Kimura, Genjiro; Ohte, Nobuyuki; Dohi, Yasuaki
2016-08-01
The close association between dietary salt and hypertension is well established. However, previous studies generally assessed salt intake without adjustment for body weight. Herein, we investigated the significance of body weight-adjusted salt intake in the general population. The present cross-sectional study included 7629 participants from our yearly physical checkup program, and their salt intake was assessed using a spot urine test to estimate 24-hour urinary salt excretion. Total salt intake increased with increasing body weight. Body weight-adjusted salt intake was greater in participants with hypertension than in those without hypertension. Systolic blood pressure, estimated glomerular filtration rate, and urinary albumin were independently correlated with body weight-adjusted salt intake after adjustment for possible cardiovascular risk factors. Excessive body weight-adjusted salt intake could be related to an increase in blood pressure and hypertensive organ damage. Adjustment for body weight might therefore provide clinically important information when assessing individual salt intake. Copyright © 2016 American Society of Hypertension. Published by Elsevier Inc. All rights reserved.
State demonstration project : loop detectors.
DOT National Transportation Integrated Search
1985-01-01
The Virginia Department of Highways and Transportation frequently utilizes induction loops in its vehicle detector systems. Although not documented, there have been many instances of loop failure; therefore, the practices and materials used by the De...
Early Detection of Salt Stress Damage by Biophotons in Red Bean Seedling
NASA Astrophysics Data System (ADS)
Ohya, Tomoyuki; Kurashige, Hideaki; Okabe, Hirotaka; Kai, Shoichi
2000-06-01
The optical detection of the stress damage to plants by NaCl solutions was attempted during germination of a seed and growth of a root. We compared the photon intensity of red beans before and after NaCl treatment and found that the photon intensity after NaCl treatment decreased as the NaCl concentration increased. For the saturated NaCl concentration (4.5 M), however, the observed photon intensity drastically increased, and the simultaneous destruction of cell membranes was observed. The intensity of biophoton emission from red beans showed characteristic change with salt concentrations. When the salt stress was applied to the red beans at an early growth stage, their root elongations were suppressed and photon intensity from the root decreased. This was not the case for the root at the late stage. This shows that biophoton intensity due to salt stress depends on not only NaCl concentration but also the growth stage of the plant. We may conclude that the extent of damage to roots by salt stress can be evaluated from biophoton response.
Force-Free Magnetic Fields Calculated from Automated Tracing of Coronal Loops with AIA/SDO
NASA Astrophysics Data System (ADS)
Aschwanden, M. J.
2013-12-01
One of the most realistic magnetic field models of the solar corona is a nonlinear force-free field (NLFFF) solution. There exist about a dozen numeric codes that compute NLFFF solutions based on extrapolations of photospheric vector magnetograph data. However, since the photosphere and lower chromosphere is not force-free, a suitable correction has to be applied to the lower boundary condition. Despite of such "pre-processing" corrections, the resulting theoretical magnetic field lines deviate substantially from observed coronal loop geometries. - Here we developed an alternative method that fits an analytical NLFFF approximation to the observed geometry of coronal loops. The 2D coordinates of the geometry of coronal loop structures observed with AIA/SDO are traced with the "Oriented Coronal CUrved Loop Tracing" (OCCULT-2) code, an automated pattern recognition algorithm that has demonstrated the fidelity in loop tracing matching visual perception. A potential magnetic field solution is then derived from a line-of-sight magnetogram observed with HMI/SDO, and an analytical NLFFF approximation is then forward-fitted to the twisted geometry of coronal loops. We demonstrate the performance of this magnetic field modeling method for a number of solar active regions, before and after major flares observed with SDO. The difference of the NLFFF and the potential field energies allows us then to compute the free magnetic energy, which is an upper limit of the energy that is released during a solar flare.
COMPLEX EVOLUTION OF BILE SALTS IN BIRDS
Hagey, Lee R.; Vidal, Nicolas; Hofmann, Alan F.; Krasowski, Matthew D.
2010-01-01
Bile salts are the major end-metabolites of cholesterol and are important in lipid digestion and shaping of the gut microflora. There have been limited studies of bile-salt variation in birds. The purpose of our study was to determine bile-salt variation among birds and relate this variation to current avian phylogenies and hypotheses on the evolution of bile salt pathways. We determined the biliary bile-salt composition of 405 phylogenetically diverse bird species, including 7 paleognath species. Bile salt profiles were generally stable within bird families. Complex bile-salt profiles were more common in omnivores and herbivores than in carnivores. The structural variation of bile salts in birds is extensive and comparable to that seen in surveys of bile salts in reptiles and mammals. Birds produce many of the bile salts found throughout nonavian vertebrates and some previously uncharacterized bile salts. One difference between birds and other vertebrates is extensive hydroxylation of carbon-16 of bile salts in bird species. Comparison of our data set of bird bile salts with that of other vertebrates, especially reptiles, allowed us to infer evolutionary changes in the bile salt synthetic pathway. PMID:21113274
Field, Kevin G.; Briggs, Samuel A.; Hu, Xunxiang; ...
2016-11-01
FeCrAl alloys are an attractive materials class for nuclear power applications due to their increased environmental compatibility over more traditional nuclear materials. Preliminary studies into the radiation tolerance of FeCrAl alloys under accelerated neutron testing between 300-400 °C have shown post-irradiation microstructures containing dislocation loops and Cr-rich ' phase. Although these initial works established the post-irradiation microstructures, little to no focus was applied towards the influence of pre-irradiation microstructures on this response. Here, a well annealed commercial FeCrAl alloy, Alkrothal 720, was neutron irradiated to 1.8 dpa at 382 °C and then the role of random high angle grain boundariesmore » on the spatial distribution and size of dislocation loops, dislocation loops, and black dot damage was analyzed using on-zone scanning transmission electron microscopy. Results showed a clear heterogeneous dislocation loop formation with dislocation loops showing an increased number density and size, black dot damage showing a significant number density decrease, and an increased size of dislocation loops in the vicinity directly adjacent to the grain boundary. Lastly, these results suggest the importance of the pre-irradiation microstructure on the radiation tolerance of FeCrAl alloys.« less
Microplastic Pollution in Table Salts from China.
Yang, Dongqi; Shi, Huahong; Li, Lan; Li, Jiana; Jabeen, Khalida; Kolandhasamy, Prabhu
2015-11-17
Microplastics have been found in seas all over the world. We hypothesize that sea salts might contain microplastics, because they are directly supplied by seawater. To test our hypothesis, we collected 15 brands of sea salts, lake salts, and rock/well salts from supermarkets throughout China. The microplastics content was 550-681 particles/kg in sea salts, 43-364 particles/kg in lake salts, and 7-204 particles/kg in rock/well salts. In sea salts, fragments and fibers were the prevalent types of particles compared with pellets and sheets. Microplastics measuring less than 200 μm represented the majority of the particles, accounting for 55% of the total microplastics, and the most common microplastics were polyethylene terephthalate, followed by polyethylene and cellophane in sea salts. The abundance of microplastics in sea salts was significantly higher than that in lake salts and rock/well salts. This result indicates that sea products, such as sea salts, are contaminated by microplastics. To the best of our knowledge, this is the first report on microplastic pollution in abiotic sea products.
NASA Astrophysics Data System (ADS)
Liu, T.; Harman, C. J.; Kipnis, E. L.; Bowen, B. B.
2017-12-01
Public concern about apparent reductions in the areal extent of the Bonneville Salt Flat (BSF) and perceived changes in inundation frequency has motivated renewed interest in the hydrologic and geochemical behavior of this salt playa. In this study, we develop a numerical modeling framework to simulate the relationship between hydrometeorologic variability, brine evaporation and salt crystallization processes on BSF. The BSF, locates in Utah, is the remnant of paleo-lake Bonneville, and is capped by up to 1 meter of salt deposition over a 100 km2 area. The BSF has two distinct hydrologic periods each year: a winter wet periods with standing surface brine and the summer dry periods when the brine is evaporated, exposing the surface salt crust. We develop a lumped non-linear dynamical models coupling conservation expressions from water, dissolved salt and thermal energy to investigate the seasonal and diurnal behavior of brine during the transition from standing brine to exposed salt at BSF. The lumped dynamic models capture important nonlinear and kinetic effects introduced by the high ionic concentration of the brine, including the pronounced effect of the depressed water activity coefficient on evaporation. The salt crystallization and dissolution rate is modeled as a kinetic process linearly proportional to the degree of supersaturation of brine. The model generates predictions of the brine temperature and the solute and solvent masses controlled by diurnal net radiation input and aerodynamic forcing. Two distinct mechanisms emerge as potential controls on salt production and dissolution: (1) evapo-concentration and (2) changes in solubility related to changes in brine temperature. Although the evaporation of water is responsible for ultimate disappearance of the brine each season ,variation in solubility is found to be the dominant control on diurnal cycles of salt precipitation and dissolution in the BSF case. Most salt is crystallized during nighttime, but the
Steady State Model for Solar Coronal Loops
NASA Astrophysics Data System (ADS)
Sugiyama, L.; Asgari-Targhi, M.
2017-12-01
Solar coronal loops on the surface of the sun provide background magnetic and plasma structures for the release of a significant amount of the sun's energy, through energetic solar flares and coronal mass ejections and more gradual processes. Understanding their steady states is the first step in understanding loop dynamics. A consistent MHD steady state model, for a curved magnetic flux rope that contains plasma, has been developed[1] for simple coronal loops with both ends anchored in the photosphere. Plasma pressure or current makes the loop unstable to expansion in major radius and must be balanced by external forces, such as the solar gravity. The MHD momentum equation has a well defined small parameter ordering in the loop inverse aspect ratio ɛ=a/Ro (minor/major radius). Different types of common coronal loops fall in different parameter regimes, determined by the relative values of the plasma beta β=po/(Bo2/2μo), the MHD gravity parameter Ĝ≡ga/vA2 (the gravitational acceleration g normalized to the minor radius a and shear Alfvén velocity vA), and ɛ. The largest possible gravity, Ĝ ɛ1β, corresponds to the largest loops because it reduces the plasma density at the top of the loop exponentially compared to its lower ends, reducing the downward gravitational force -ρĜ there. The thin loops that are ubiquitous in solar active regions have ``high'' beta, β ɛ1, for ɛ≃0.02, and fit the predicted model scalings. The thicker loops that can give rise to flares and CMEs have ``low'' beta, β ɛ2. Cool loops, such as solar filaments outside active regions, that have a central pressure lower than that of the surrounding corona would have the strongest stability against radial expansion. The model raises a number of questions about the connection of loops to the photosphere and the force-free nature of the magnetic field there. [1] L. Sugiyama, M. Asgari-Targhi, Phys. Plasmas 24, 022904 (2017).
Presenting simulation results in a nested loop plot.
Rücker, Gerta; Schwarzer, Guido
2014-12-12
Statisticians investigate new methods in simulations to evaluate their properties for future real data applications. Results are often presented in a number of figures, e.g., Trellis plots. We had conducted a simulation study on six statistical methods for estimating the treatment effect in binary outcome meta-analyses, where selection bias (e.g., publication bias) was suspected because of apparent funnel plot asymmetry. We varied five simulation parameters: true treatment effect, extent of selection, event proportion in control group, heterogeneity parameter, and number of studies in meta-analysis. In combination, this yielded a total number of 768 scenarios. To present all results using Trellis plots, 12 figures were needed. Choosing bias as criterion of interest, we present a 'nested loop plot', a diagram type that aims to have all simulation results in one plot. The idea was to bring all scenarios into a lexicographical order and arrange them consecutively on the horizontal axis of a plot, whereas the treatment effect estimate is presented on the vertical axis. The plot illustrates how parameters simultaneously influenced the estimate. It can be combined with a Trellis plot in a so-called hybrid plot. Nested loop plots may also be applied to other criteria such as the variance of estimation. The nested loop plot, similar to a time series graph, summarizes all information about the results of a simulation study with respect to a chosen criterion in one picture and provides a suitable alternative or an addition to Trellis plots.
Open-loop control of quasiperiodic thermoacoustic oscillations
NASA Astrophysics Data System (ADS)
Guan, Yu; Gupta, Vikrant; Kashinath, Karthik; Li, Larry K. B.
2017-11-01
The open-loop application of periodic acoustic forcing has been shown to be a potentially effective strategy for controlling periodic thermoacoustic oscillations, but its effectiveness on aperiodic thermoacoustic oscillations is less clear. In this experimental study, we apply periodic acoustic forcing to a ducted premixed flame oscillating quasiperiodically at two incommensurate natural frequencies, f1 and f2. We find that (i) above a critical forcing amplitude, the system locks into the forcing by oscillating only at the forcing frequency ff, producing a closed periodic orbit in phase space with no evidence of the original T2 torus attractor; (ii) the critical forcing amplitude required for lock-in decreases as ff approaches either f1 or f2, resulting in characteristic ∨-shaped lock-in boundaries around the two natural modes; and (iii) for a wide range of forcing frequencies, the system's oscillation amplitude can be reduced to less than 20% of that of the unforced system. These findings show that the open-loop application of periodic acoustic forcing can be an effective strategy for controlling aperiodic thermoacoustic oscillations. This work was supported by the Research Grants Council of Hong Kong (Project No. 16235716 and 26202815).
Mervaala, E. M.; Paakkari, I.; Laakso, J.; Nevala, R.; Teräväinen, T. M.; Fyhrquist, F.; Vapaatalo, H.; Karppanen, H.
1994-01-01
1. The influence of salt (sodium chloride; NaCl) (an additional 6% in the diet) and that of a novel sodium-reduced, potassium-, magnesium-, and L-lysine-enriched salt alternative on the cardiovascular effects of ramipril was studied in stroke-prone spontaneously hypertensive rats in a 6-week study. The intake of sodium chloride was adjusted to the same level by adding the salt alternative at a 1.75 times higher amount than regular salt. 2. Salt produced a marked rise in blood pressure and induced cardiac hypertrophy and significant mortality, while the salt alternative neither increased blood pressure nor caused any mortality and produced less cardiac hypertrophy than salt. 3. Ramipril treatment at a daily dose of 3 mg kg-1 normalized blood pressure and prevented the development of cardiac hypertrophy of rats on control diet. These effects of ramipril were blocked by the addition of salt but were only slightly attenuated by the addition of the salt alternative. The mortality in the salt group was prevented by ramipril. 4. Responses of mesenteric arterial rings in vitro were examined at the end of the study. Salt, but not the salt alternative, increased vascular contractile responses to noradrenaline. Ramipril treatment improved the arterial relaxation responses to acetylcholine and to sodium nitroprusside. The vascular relaxation enhancing effect of ramipril was blocked by salt but only slightly attenuated by the salt alternative. 5. Ramipril treatment did not significantly increase plasma renin activity in the presence or in the absence of salt supplementation. The salt alternative did not cause hyperkalaemia, either alone or in combination with ramipril treatment.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:8032605
ABA Is Required for Plant Acclimation to a Combination of Salt and Heat Stress.
Suzuki, Nobuhiro; Bassil, Elias; Hamilton, Jason S; Inupakutika, Madhuri A; Zandalinas, Sara Izquierdo; Tripathy, Deesha; Luo, Yuting; Dion, Erin; Fukui, Ginga; Kumazaki, Ayana; Nakano, Ruka; Rivero, Rosa M; Verbeck, Guido F; Azad, Rajeev K; Blumwald, Eduardo; Mittler, Ron
2016-01-01
Abiotic stresses such as drought, heat or salinity are a major cause of yield loss worldwide. Recent studies revealed that the acclimation of plants to a combination of different environmental stresses is unique and cannot be directly deduced from studying the response of plants to each of the different stresses applied individually. Here we report on the response of Arabidopsis thaliana to a combination of salt and heat stress using transcriptome analysis, physiological measurements and mutants deficient in abscisic acid, salicylic acid, jasmonic acid or ethylene signaling. Arabidopsis plants were found to be more susceptible to a combination of salt and heat stress compared to each of the different stresses applied individually. The stress combination resulted in a higher ratio of Na+/K+ in leaves and caused the enhanced expression of 699 transcripts unique to the stress combination. Interestingly, many of the transcripts that specifically accumulated in plants in response to the salt and heat stress combination were associated with the plant hormone abscisic acid. In accordance with this finding, mutants deficient in abscisic acid metabolism and signaling were found to be more susceptible to a combination of salt and heat stress than wild type plants. Our study highlights the important role abscisic acid plays in the acclimation of plants to a combination of two different abiotic stresses.
ABA Is Required for Plant Acclimation to a Combination of Salt and Heat Stress
Suzuki, Nobuhiro; Bassil, Elias; Hamilton, Jason S.; Inupakutika, Madhuri A.; Zandalinas, Sara Izquierdo; Tripathy, Deesha; Luo, Yuting; Dion, Erin; Fukui, Ginga; Kumazaki, Ayana; Nakano, Ruka; Rivero, Rosa M.; Verbeck, Guido F.; Azad, Rajeev K.; Blumwald, Eduardo; Mittler, Ron
2016-01-01
Abiotic stresses such as drought, heat or salinity are a major cause of yield loss worldwide. Recent studies revealed that the acclimation of plants to a combination of different environmental stresses is unique and cannot be directly deduced from studying the response of plants to each of the different stresses applied individually. Here we report on the response of Arabidopsis thaliana to a combination of salt and heat stress using transcriptome analysis, physiological measurements and mutants deficient in abscisic acid, salicylic acid, jasmonic acid or ethylene signaling. Arabidopsis plants were found to be more susceptible to a combination of salt and heat stress compared to each of the different stresses applied individually. The stress combination resulted in a higher ratio of Na+/K+ in leaves and caused the enhanced expression of 699 transcripts unique to the stress combination. Interestingly, many of the transcripts that specifically accumulated in plants in response to the salt and heat stress combination were associated with the plant hormone abscisic acid. In accordance with this finding, mutants deficient in abscisic acid metabolism and signaling were found to be more susceptible to a combination of salt and heat stress than wild type plants. Our study highlights the important role abscisic acid plays in the acclimation of plants to a combination of two different abiotic stresses. PMID:26824246
Feasibility of laser-induced breakdown spectroscopy (LIBS) for classification of sea salts.
Tan, Man Minh; Cui, Sheng; Yoo, Jonghyun; Han, Song-Hee; Ham, Kyung-Sik; Nam, Sang-Ho; Lee, Yonghoon
2012-03-01
We have investigated the feasibility of laser-induced breakdown spectroscopy (LIBS) as a fast, reliable classification tool for sea salts. For 11 kinds of sea salts, potassium (K), magnesium (Mg), calcium (Ca), and aluminum (Al), concentrations were measured by inductively coupled plasma-atomic emission spectroscopy (ICP-AES), and the LIBS spectra were recorded in the narrow wavelength region between 760 and 800 nm where K (I), Mg (I), Ca (II), Al (I), and cyanide (CN) band emissions are observed. The ICP-AES measurements revealed that the K, Mg, Ca, and Al concentrations varied significantly with the provenance of each salt. The relative intensities of the K (I), Mg (I), Ca (II), and Al (I) peaks observed in the LIBS spectra are consistent with the results using ICP-AES. The principal component analysis of the LIBS spectra provided the score plot with quite a high degree of clustering. This indicates that classification of sea salts by chemometric analysis of LIBS spectra is very promising. Classification models were developed by partial least squares discriminant analysis (PLS-DA) and evaluated. In addition, the Al (I) peaks enabled us to discriminate between different production methods of the salts. © 2012 Society for Applied Spectroscopy
Iodized salt sales in the United States.
Maalouf, Joyce; Barron, Jessica; Gunn, Janelle P; Yuan, Keming; Perrine, Cria G; Cogswell, Mary E
2015-03-10
Iodized salt has been an important source of dietary iodine, a trace element important for regulating human growth, development, and metabolic functions. This analysis identified iodized table salt sales as a percentage of retail salt sales using Nielsen ScanTrack. We identified 1117 salt products, including 701 salt blends and 416 other salt products, 57 of which were iodized. When weighted by sales volume in ounces or per item, 53% contained iodized salt. These findings may provide a baseline for future monitoring of sales of iodized salt.
A dynamic flare with anomalously dense flare loops
NASA Technical Reports Server (NTRS)
Svestka, Z.; Fontenla, J. M.; Machado, M. E.; Martin, S. F.; Neidig, D. F.
1986-01-01
The dynamic flare of November 6, 1980 developed a rich system of growing loops which could be followed in H-alpha for 1.5 hours. Throughout the flare, these loops, near the limb, were seen in emission against the disk. Theoretical computations of b-values for a hydrogen atom reveal that this requires electron densities in the loops to be close to 10 to the 12th per cu cm. From measured widths of higher Balmer lines the density at the tops of the loops was found to be 4 x 10 to the 12th per cu cm if no nonthermal motions were present. It is now general knowledge that flare loops are initially observed in X-rays and become visible in H-alpha only after cooling. For such a high density a loop would cool through radiation from 10 to the 7th K to 10 to the 4th K within a few minutes so that the dense H-alpha loops should have heights very close to the heights of the X-ray loops. This, however, contradicts the observations obtained by the HXIS and FCS instruments on board SMM which show the X-ray loops at much higher altitudes than the loops in H-alpha. Therefore, the density must have been significantly smaller when the loops were formed and the flare loops were apparently both shrinking and becoming denser while cooling.
Automatic blocking of nested loops
NASA Technical Reports Server (NTRS)
Schreiber, Robert; Dongarra, Jack J.
1990-01-01
Blocked algorithms have much better properties of data locality and therefore can be much more efficient than ordinary algorithms when a memory hierarchy is involved. On the other hand, they are very difficult to write and to tune for particular machines. The reorganization is considered of nested loops through the use of known program transformations in order to create blocked algorithms automatically. The program transformations used are strip mining, loop interchange, and a variant of loop skewing in which invertible linear transformations (with integer coordinates) of the loop indices are allowed. Some problems are solved concerning the optimal application of these transformations. It is shown, in a very general setting, how to choose a nearly optimal set of transformed indices. It is then shown, in one particular but rather frequently occurring situation, how to choose an optimal set of block sizes.
A classical model for closed-loop diagrams of binary liquid mixtures
DOE Office of Scientific and Technical Information (OSTI.GOV)
Schnitzler, J.v.; Prausnitz, J.M.
1994-03-01
A classical lattice model for closed-loop temperature-composition phase diagrams has been developed. It considers the effect of specific interactions, such as hydrogen bonding, between dissimilar components. This van Laar-type model includes a Flory-Huggins term for the excess entropy of mixing. It is applied to several liquid-liquid equilibria of nonelectrolytes, where the molecules of the two components differ in size. The model is able to represent the observed data semi-quantitatively, but in most cases it is not flexible enough to predict all parts of the closed loop quantitatively. The ability of the model to represent different binary systems is discussed. Finally,more » attention is given to a correction term, concerning the effect of concentration fluctuations near the upper critical solution temperature.« less
2018-06-11
Giant, bright coronal loops trace out the magnetic field lines above an active region from June 4-6, 2018. The wavelength of extreme ultraviolet light shown here is emitted by ionized iron travelling along the field lines, super-heated to approximately 1 million degrees K. Coronal loops were not seen in this level of detail until the Solar Dynamics Observatory was launched in 2010 and came online, giving solar scientists new data with which to study the Sun and its processes. https://photojournal.jpl.nasa.gov/catalog/PIA22508
Community solar salt production in Goa, India
2012-01-01
Traditional salt farming in Goa, India has been practised for the past 1,500 years by a few communities. Goa’s riverine estuaries, easy access to sea water and favourable climatic conditions makes salt production attractive during summer. Salt produced through this natural evaporation process also played an important role in the economy of Goa even during the Portuguese rule as salt was the chief export commodity. In the past there were 36 villages involved in salt production, which is now reduced to 9. Low income, lack of skilled labour, competition from industrially produced salt, losses incurred on the yearly damage of embankments are the major reasons responsible for the reduction in the number of salt pans. Salt pans (Mithagar or Mithache agor) form a part of the reclaimed waterlogged khazan lands, which are also utilised for aquaculture, pisciculture and agriculture. Salt pans in Goa experience three phases namely, the ceased phase during monsoon period of June to October, preparatory phase from December to January, and salt harvesting phase, from February to June. After the monsoons, the salt pans are prepared manually for salt production. During high tide, an influx of sea water occurs, which enters the reservoir pans through sluice gates. The sea water after 1–2 days on attaining a salinity of approximately 5ºBé, is released into the evaporator pans and kept till it attains a salinity of 23 - 25ºBé. The brine is then released to crystallizer pans, where the salt crystallises out 25 - 27ºBé and is then harvested. Salt pans form a unique ecosystem where succession of different organisms with varying environmental conditions occurs. Organisms ranging from bacteria, archaea to fungi, algae, etc., are known to colonise salt pans and may influence the quality of salt produced. The aim of this review is to describe salt farming in Goa’s history, importance of salt production as a community activity, traditional method of salt production and the
Community solar salt production in Goa, India.
Mani, Kabilan; Salgaonkar, Bhakti B; Das, Deepthi; Bragança, Judith M
2012-12-01
Traditional salt farming in Goa, India has been practised for the past 1,500 years by a few communities. Goa's riverine estuaries, easy access to sea water and favourable climatic conditions makes salt production attractive during summer. Salt produced through this natural evaporation process also played an important role in the economy of Goa even during the Portuguese rule as salt was the chief export commodity. In the past there were 36 villages involved in salt production, which is now reduced to 9. Low income, lack of skilled labour, competition from industrially produced salt, losses incurred on the yearly damage of embankments are the major reasons responsible for the reduction in the number of salt pans.Salt pans (Mithagar or Mithache agor) form a part of the reclaimed waterlogged khazan lands, which are also utilised for aquaculture, pisciculture and agriculture. Salt pans in Goa experience three phases namely, the ceased phase during monsoon period of June to October, preparatory phase from December to January, and salt harvesting phase, from February to June. After the monsoons, the salt pans are prepared manually for salt production. During high tide, an influx of sea water occurs, which enters the reservoir pans through sluice gates. The sea water after 1-2 days on attaining a salinity of approximately 5ºBé, is released into the evaporator pans and kept till it attains a salinity of 23 - 25ºBé. The brine is then released to crystallizer pans, where the salt crystallises out 25 - 27ºBé and is then harvested.Salt pans form a unique ecosystem where succession of different organisms with varying environmental conditions occurs. Organisms ranging from bacteria, archaea to fungi, algae, etc., are known to colonise salt pans and may influence the quality of salt produced.The aim of this review is to describe salt farming in Goa's history, importance of salt production as a community activity, traditional method of salt production and the biota
Critical bifurcation of shallow microtidal landforms in tidal flats and salt marshes
Fagherazzi, Sergio; Carniello, Luca; D'Alpaos, Luigi; Defina, Andrea
2006-01-01
Shallow tidal basins are characterized by extensive tidal flats and salt marshes that lie within specific ranges of elevation, whereas intermediate elevations are less frequent in intertidal landscapes. Here we show that this bimodal distribution of elevations stems from the characteristics of wave-induced sediment resuspension and, in particular, from the reduction of maximum wave height caused by dissipative processes in shallow waters. The conceptual model presented herein is applied to the Venice Lagoon, Italy, and demonstrates that areas at intermediate elevations are inherently unstable and tend to become either tidal flats or salt marshes. PMID:16707583
The Projectile Inside the Loop
ERIC Educational Resources Information Center
Varieschi, Gabriele U.
2006-01-01
The loop-the-loop demonstration can be easily adapted to study the kinematics of projectile motion, when the moving body falls inside the apparatus. Video capturing software can be used to reveal peculiar geometrical effects of this simple but educational experiment.
NASA Astrophysics Data System (ADS)
Adenariwo, Adepoju
The efficiency of nuclear reactors can be improved by increasing the operating pressure of current nuclear reactors. Current CANDU-type nuclear reactors use heavy water as coolant at an outlet pressure of up to 11.5 MPa. Conceptual SuperCritical Water Reactors (SCWRs) will operate at a higher coolant outlet pressure of 25 MPa. Supercritical water technology has been used in advanced coal plants and its application proves promising to be employed in nuclear reactors. To better understand how supercritical water technology can be applied in nuclear power plants, supercritical water loops are used to study the heat transfer phenomena as it applies to CANDU-type reactors. A conceptual design of a loop known as the Supercritical Phenomena Experimental Apparatus (SPETA) has been done. This loop has been designed to fit in a 9 m by 2 m by 2.8 m enclosure that will be installed at the University of Ontario Institute of Technology Energy Research Laboratory. The loop include components to safely start up and shut down various test sections, produce a heat source to the test section, and to remove reject heat. It is expected that loop will be able to investigate the behaviour of supercritical water in various geometries including bare tubes, annulus tubes, and multi-element-type bundles. The experimental geometries are designed to match the fluid properties of Canadian SCWR fuel channel designs so that they are representative of a practical application of supercritical water technology in nuclear plants. This loop will investigate various test section orientations which are the horizontal, vertical, and inclined to investigate buoyancy effects. Frictional pressure drop effects and satisfactory methods of estimating hydraulic resistances in supercritical fluid shall also be estimated with the loop. Operating limits for SPETA have been established to be able to capture the important heat transfer phenomena at supercritical conditions. Heat balance and flow calculations have
ERIC Educational Resources Information Center
Cetin, Ibrahim
2015-01-01
The purpose of this study is to explore students' understanding of loops and nested loops concepts. Sixty-three mechanical engineering students attending an introductory programming course participated in the study. APOS (Action, Process, Object, Schema) is a constructivist theory developed originally for mathematics education. This study is the…
NASA Astrophysics Data System (ADS)
Rück, Marlon; Reuther, Johannes
2018-04-01
We implement an extension of the pseudofermion functional renormalization group method for quantum spin systems that takes into account two-loop diagrammatic contributions. An efficient numerical treatment of the additional terms is achieved within a nested graph construction which recombines different one-loop interaction channels. In order to be fully self-consistent with respect to self-energy corrections, we also include certain three-loop terms of Katanin type. We first apply this formalism to the antiferromagnetic J1-J2 Heisenberg model on the square lattice and benchmark our results against the previous one-loop plus Katanin approach. Even though the renormalization group (RG) equations undergo significant modifications when including the two-loop terms, the magnetic phase diagram, comprising Néel ordered and collinear ordered phases separated by a magnetically disordered regime, remains remarkably unchanged. Only the boundary position between the disordered and the collinear phases is found to be moderately affected by two-loop terms. On the other hand, critical RG scales, which we associate with critical temperatures Tc, are reduced by a factor of ˜2 indicating that the two-loop diagrams play a significant role in enforcing the Mermin-Wagner theorem. Improved estimates for critical temperatures are also obtained for the Heisenberg ferromagnet on the three-dimensional simple cubic lattice where errors in Tc are reduced by ˜34 % . These findings have important implications for the quantum phase diagrams calculated within the previous one-loop plus Katanin approach which turn out to be already well converged.
Gordish, Kevin L; Kassem, Kamal M; Ortiz, Pablo A; Beierwaltes, William H
2017-04-01
Previously, we reported that 20% fructose diet causes salt-sensitive hypertension. In this study, we hypothesized that a high salt diet supplemented with 20% fructose (in drinking water) stimulates salt-sensitive hypertension by increasing salt retention through decreasing renal nitric oxide. Rats in metabolic cages consumed normal rat chow for 5 days (baseline), then either: (1) normal salt for 2 weeks, (2) 20% fructose in drinking water for 2 weeks, (3) 20% fructose for 1 week, then fructose + high salt (4% NaCl) for 1 week, (4) normal chow for 1 week, then high salt for 1 week, (5) 20% glucose for 1 week, then glucose + high salt for 1 week. Blood pressure, sodium excretion, and cumulative sodium balance were measured. Systolic blood pressure was unchanged by 20% fructose or high salt diet. 20% fructose + high salt increased systolic blood pressure from 125 ± 1 to 140 ± 2 mmHg ( P < 0.001). Cumulative sodium balance was greater in rats consuming fructose + high salt than either high salt, or glucose + high salt (114.2 ± 4.4 vs. 103.6 ± 2.2 and 98.6 ± 5.6 mEq/Day19; P < 0.05). Sodium excretion was lower in fructose + high salt group compared to high salt only: 5.33 ± 0.21 versus 7.67 ± 0.31 mmol/24 h; P < 0.001). Nitric oxide excretion was 2935 ± 256 μ mol/24 h in high salt-fed rats, but reduced by 40% in the 20% fructose + high salt group (2139 ± 178 μ mol /24 hrs P < 0.01). Our results suggest that fructose predisposes rats to salt-sensitivity and, combined with a high salt diet, leads to sodium retention, increased blood pressure, and impaired renal nitric oxide availability. © 2017 The Authors. Physiological Reports published by Wiley Periodicals, Inc. on behalf of The Physiological Society and the American Physiological Society.
Olson, Mark A; Feig, Michael; Brooks, Charles L
2008-04-15
This article examines ab initio methods for the prediction of protein loops by a computational strategy of multiscale conformational sampling and physical energy scoring functions. Our approach consists of initial sampling of loop conformations from lattice-based low-resolution models followed by refinement using all-atom simulations. To allow enhanced conformational sampling, the replica exchange method was implemented. Physical energy functions based on CHARMM19 and CHARMM22 parameterizations with generalized Born (GB) solvent models were applied in scoring loop conformations extracted from the lattice simulations and, in the case of all-atom simulations, the ensemble of conformations were generated and scored with these models. Predictions are reported for 25 loop segments, each eight residues long and taken from a diverse set of 22 protein structures. We find that the simulations generally sampled conformations with low global root-mean-square-deviation (RMSD) for loop backbone coordinates from the known structures, whereas clustering conformations in RMSD space and scoring detected less favorable loop structures. Specifically, the lattice simulations sampled basins that exhibited an average global RMSD of 2.21 +/- 1.42 A, whereas clustering and scoring the loop conformations determined an RMSD of 3.72 +/- 1.91 A. Using CHARMM19/GB to refine the lattice conformations improved the sampling RMSD to 1.57 +/- 0.98 A and detection to 2.58 +/- 1.48 A. We found that further improvement could be gained from extending the upper temperature in the all-atom refinement from 400 to 800 K, where the results typically yield a reduction of approximately 1 A or greater in the RMSD of the detected loop. Overall, CHARMM19 with a simple pairwise GB solvent model is more efficient at sampling low-RMSD loop basins than CHARMM22 with a higher-resolution modified analytical GB model; however, the latter simulation method provides a more accurate description of the all-atom energy
NASA Astrophysics Data System (ADS)
Li, Xuechen; Geng, Jinling; Jia, Pengying; Zhang, Panpan; Zhang, Qi; Li, Yaru
2017-11-01
Excited by an alternating current voltage, a patterned discharge and a diffuse discharge are generated in a needle to liquid configuration. Using an intensified charge-coupled device (ICCD), temporal evolution of the discharge between the two electrodes is investigated for the diffuse mode and the patterned mode, respectively. For the diffuse mode, the positive discharge is in a glow regime, and the negative discharge is in a Townsend discharge regime. For the patterned mode, the discharge always belongs to the Townsend discharge regime. Moreover, in the patterned mode, various patterns including the single loop, single loop with the surrounding corona, triple loops, and concentric loops with a central spot are observed on the water surface with the increasing positive peak-value of the applied voltage (Upp). Temporally resolved images of the loop-patterns are captured on the water surface. From the electrical measurements and the ICCD imaging, it is found that the loop pattern emerges after the discharge bridges the two electrodes. Then, it begins to evolve and finally degenerates with the decrease in the discharge current. The pattern does not disappear until the discharge quenches. Formation of the loop-patterns is attributed to the role of negative ions.
Molten salt power towers operating at 600–650 °C: Salt selection and cost benefits
Turchi, Craig S.; Vidal, Judith; Bauer, Matthew
2018-03-14
This analysis examines the potential benefit of adopting the supercritical carbon dioxide (sCO 2) Brayton cycle at 600-650 degrees C compared to the current state-of-the-art power tower operating a steam-Rankine cycle with solar salt at approximately 574 degrees C. The analysis compares a molten-salt power tower configuration using direct storage of solar salt (60:40 wt% sodium nitrate: potassium nitrate) or single-component nitrate salts at 600 degrees C or alternative carbonate- or chloride-based salts at 650 degrees C.
Molten salt power towers operating at 600–650 °C: Salt selection and cost benefits
DOE Office of Scientific and Technical Information (OSTI.GOV)
Turchi, Craig S.; Vidal, Judith; Bauer, Matthew
This analysis examines the potential benefit of adopting the supercritical carbon dioxide (sCO 2) Brayton cycle at 600-650 degrees C compared to the current state-of-the-art power tower operating a steam-Rankine cycle with solar salt at approximately 574 degrees C. The analysis compares a molten-salt power tower configuration using direct storage of solar salt (60:40 wt% sodium nitrate: potassium nitrate) or single-component nitrate salts at 600 degrees C or alternative carbonate- or chloride-based salts at 650 degrees C.
Improving predicted protein loop structure ranking using a Pareto-optimality consensus method.
Li, Yaohang; Rata, Ionel; Chiu, See-wing; Jakobsson, Eric
2010-07-20
Accurate protein loop structure models are important to understand functions of many proteins. Identifying the native or near-native models by distinguishing them from the misfolded ones is a critical step in protein loop structure prediction. We have developed a Pareto Optimal Consensus (POC) method, which is a consensus model ranking approach to integrate multiple knowledge- or physics-based scoring functions. The procedure of identifying the models of best quality in a model set includes: 1) identifying the models at the Pareto optimal front with respect to a set of scoring functions, and 2) ranking them based on the fuzzy dominance relationship to the rest of the models. We apply the POC method to a large number of decoy sets for loops of 4- to 12-residue in length using a functional space composed of several carefully-selected scoring functions: Rosetta, DOPE, DDFIRE, OPLS-AA, and a triplet backbone dihedral potential developed in our lab. Our computational results show that the sets of Pareto-optimal decoys, which are typically composed of approximately 20% or less of the overall decoys in a set, have a good coverage of the best or near-best decoys in more than 99% of the loop targets. Compared to the individual scoring function yielding best selection accuracy in the decoy sets, the POC method yields 23%, 37%, and 64% less false positives in distinguishing the native conformation, indentifying a near-native model (RMSD < 0.5A from the native) as top-ranked, and selecting at least one near-native model in the top-5-ranked models, respectively. Similar effectiveness of the POC method is also found in the decoy sets from membrane protein loops. Furthermore, the POC method outperforms the other popularly-used consensus strategies in model ranking, such as rank-by-number, rank-by-rank, rank-by-vote, and regression-based methods. By integrating multiple knowledge- and physics-based scoring functions based on Pareto optimality and fuzzy dominance, the POC method is
Method of Implementing Digital Phase-Locked Loops
NASA Technical Reports Server (NTRS)
Stephens, Scott A. (Inventor); Thomas, J. Brooks (Inventor)
1997-01-01
In a new formulation for digital phase-locked loops, loop-filter constants are determined from loop roots that can each be selectively placed in the s-plane on the basis of a new set of parameters, each with simple and direct physical meaning in terms of loop noise bandwidth, root-specific decay rate, and root-specific damping. Loops of first to fourth order are treated in the continuous-update approximation (B(sub L)T approaches 0) and in a discrete-update formulation with arbitrary B(sub L)T. Deficiencies of the continuous-update approximation in large-B(sub L)T applications are avoided in the new discrete-update formulation.
Premeasured Chordal Loops for Mitral Valve Repair.
Gillinov, Marc; Quinn, Reed; Kerendi, Faraz; Gaudiani, Vince; Shemin, Richard; Barnhart, Glenn; Raines, Edward; Gerdisch, Marc W; Banbury, Michael
2016-09-01
Premeasured expanded polytetrafluoroethylene chordal loops with integrated sutures for attachment to the papillary muscle and leaflet edges facilitate correction of mitral valve prolapse. Configured as a group of 3 loops (length range 12 to 24 mm), the loops are attached to a pledget that is passed through the papillary muscle and tied. Each of the loops has 2 sutures with attached needles; these needles are passed through the free edge of the leaflet and then the sutures are tied to each other, securing the chordal loop to the leaflet. Copyright © 2016 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.
NASA Astrophysics Data System (ADS)
Del Vescovo, D.; D'Ambrogio, W.
1995-01-01
A frequency domain method is presented to design a closed-loop control for vibration reduction flexible mechanisms. The procedure is developed on a single-link flexible arm, driven by one rotary degree of freedom servomotor, although the same technique may be applied to similar systems such as supports for aerospace antennae or solar panels. The method uses the structural frequency response functions (FRFs), thus avoiding system identification, that produces modeling uncertainties. Two closed-loops are implemented: the inner loop uses acceleration feedback with the aim of making the FRF similar to that of an equivalent rigid link; the outer loop feeds back displacements to achieve a fast positioning response and null steady state error. In both cases, the controller type is established a priori, while actual characteristics are defined by an optimisation procedure in which the relevant FRF is constrained into prescribed bounds and stability is taken into account.
A social feedback loop for speech development and its reduction in autism.
Warlaumont, Anne S; Richards, Jeffrey A; Gilkerson, Jill; Oller, D Kimbrough
2014-07-01
We analyzed the microstructure of child-adult interaction during naturalistic, daylong, automatically labeled audio recordings (13,836 hr total) of children (8- to 48-month-olds) with and without autism. We found that an adult was more likely to respond when the child's vocalization was speech related rather than not speech related. In turn, a child's vocalization was more likely to be speech related if the child's previous speech-related vocalization had received an immediate adult response rather than no response. Taken together, these results are consistent with the idea that there is a social feedback loop between child and caregiver that promotes speech development. Although this feedback loop applies in both typical development and autism, children with autism produced proportionally fewer speech-related vocalizations, and the responses they received were less contingent on whether their vocalizations were speech related. We argue that such differences will diminish the strength of the social feedback loop and have cascading effects on speech development over time. Differences related to socioeconomic status are also reported. © The Author(s) 2014.
USDA-ARS?s Scientific Manuscript database
: In this study, we used a diverse panel of alfalfa accessions to identify molecular markers associated with salt tolerance during germination by genome-wide association (GWA) mapping and genotyping-by-sequencing (GBS). Three levels of salt treatments were applied during seed germination. Phenotypic...
Modulation of critical brain dynamics using closed-loop neurofeedback stimulation.
Zhigalov, Alexander; Kaplan, Alexander; Palva, J Matias
2016-08-01
EEG long-range temporal correlations (LRTCs) are a significant for both human cognition and brain disorders, but beyond suppression by sensory disruption, there are little means for influencing them non-invasively. We hypothesized that LRTCs could be controlled by engaging intrinsic neuroregulation through closed-loop neurofeedback stimulation. We used a closed-loop-stimulation paradigm where supra-threshold α-waves trigger visual flash stimuli while the subject performs the standard eyes-closed resting-state task. As a "sham" control condition, we applied similar stimulus sequences without the neurofeedback. Over three sessions, a significant difference in the LRTCs of α-band oscillations (U=89, p<0.028, Wilcoxon rank sum test) and their scalp topography (T=-2.92, p<0.010, T-test) emerged between the neurofeedback and sham conditions so that the LRTCs were stronger during neurofeedback than sham. No changes (F=0.16, p>0.69, ANOVA test) in the scalp topography of α-band power were observed in either condition. This study provides proof-of-concept for that EEG LRTCs, and hence critical brain dynamics, can be modulated with closed-loop stimulation in an automatic, involuntary fashion. We suggest that this modulation is mediated by an excitation-inhibition balance change achieved by the closed-loop neuroregulation. Automatic LRTC modulation opens novel avenues for both examining the functional roles of brain criticality in healthy subjects and for developing novel therapeutic approaches for brain disorders associated with abnormal LRTCs. Copyright © 2016 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.
Cáceres-Delpiano, Javier; Teneb, Jaime; Mansilla, Rodrigo; García, Apolinaria; Salas-Burgos, Alexis
2015-06-26
Helicobacter pylori is an important factor in the development of diseases such as ulcer and gastric cancer. This bacterium uses a periplasmic transporter, UreI, to deliver urea to the intracelullar space, where later it is transformed into ammonia by the cytoplasmic enzyme urease to survive the acidic condition of the human stomach. The UreI transporter presents a pH-dependent activity, where this pH-dependence remains unknown at a structural level. Althought the existance of several protonable residues in the periplasmic loops are related to the pH-dependent activity, we find interesting to have a clear view of the conformational changes involved in this phenomena through a molecular dynamic study. Molecular dynamic simulations of the UreI transporter at three different pH conditions were performed, revealing two main pH-dependent conformations, which we present as the open and close states. We find that salt bridges between the periplasmic loops are crucial interactions that stabilize these conformations. Besides, a cooperative behaviour exists between the six subunits of the system that is necessary to fulfill the activity of this transporter. We found different pH-dependent conformations of the urea transporter UreI from Helicobacter pylori, which are related to salt-bridge interactions in the periplasmic regions. The behaviour of every channel in the system is not independent, given the existance of a cooperative behaviour through the formation of salt-bridges between the subunits of the hexameric system. We believe that our results will be related to the generation of new eradication therapies using this transporter as an attractive target, denoting that the knowledge of the possible pH-dependent conformations adopted for this transporter are important for the development of rational drug design approximations.
An Optimized Integrator Windup Protection Technique Applied to a Turbofan Engine Control
NASA Technical Reports Server (NTRS)
Watts, Stephen R.; Garg, Sanjay
1995-01-01
This paper introduces a new technique for providing memoryless integrator windup protection which utilizes readily available optimization software tools. This integrator windup protection synthesis provides a concise methodology for creating integrator windup protection for each actuation system loop independently while assuring both controller and closed loop system stability. The individual actuation system loops' integrator windup protection can then be combined to provide integrator windup protection for the entire system. This technique is applied to an H(exp infinity) based multivariable control designed for a linear model of an advanced afterburning turbofan engine. The resulting transient characteristics are examined for the integrated system while encountering single and multiple actuation limits.
Loop Evolution Observed with AIA and Hi-C
NASA Technical Reports Server (NTRS)
Mulu-Moore, Fana; Winebarger, Amy R.; Cirtain, Jonathan W.; Kobayashi, Ken; Korreck, Kelly E.; Golub, Leon; Kuzin, Sergei; Walsh, Robert William; DeForest, Craig E.; De Pontieu, Bart;
2012-01-01
In the past decade, the evolution of EUV loops has been used to infer the loop substructure. With the recent launch of High Resolution Coronal Imager (Hi-C), this inference can be validated. In this presentation we discuss the first results of loop analysis comparing AIA and Hi-C data. In the past decade, the evolution of EUV loops has been used to infer the loop substructure. With the recent launch of High Resolution Coronal Imager (Hi-C), this inference can be validated. In this presentation we discuss the first results of loop analysis comparing AIA and Hi-C data.
Liu, Fu-zhi; Yang, Jun
2015-11-01
Licorice seedlings were taken as experimental materials, an experiment was conducted to study the effects of exogenous sucrose on growth and active ingredient content of licorice seedlings under NaCl stress conditions. The results of this study showed that under salt stress conditions, after adding a certain concentration of exogenous sucrose, the licorice seedlings day of relative growth rate was increasing, and this stress can be a significant weakening effect, indicating that exogenous sucrose salt stress-relieving effect. The total flavonoids and phenylalanine ammonia lyase (PAL) activity were significantly increased, the exogenous sucrose can mitigated the seedling roots under salt stress, the licorice flavonoid content in the enhanced growth was largely due to the activity of PAL an increased, when the concentration of exogenous sucrose wae 10 mmol x L(-1), PAL activity reaching a maximum, when the concentration of exogenous sucrose was 15 mmol x L(-1), PAL activity turned into a downward trend, the results indicating that this mitigation has concentration effect. After applying different concentrations of exogenous sugar, the contents of liquiritin changes with the change of flavonoids content was similar. After applying different concentrations of exogenous sucrose, the content of licorice acid under salt stress was higher than the levels were not reached during salt stress, the impact of exogenous sucrose concentration gradient of licorice acid accumulation was not obvious.
Guo, Rui; Shi, LianXuan; Yan, Changrong; Zhong, Xiuli; Gu, FengXue; Liu, Qi; Xia, Xu; Li, Haoru
2017-02-10
Soil salinity and alkalinity present a serious threat to global agriculture. However, most of the studies have focused on neutral salt stress, and the information on the metabolic responses of plants to alkaline salt stress is limited. This investigation aimed at determining the influence of neutral salt and alkaline salt stresses on the content of metal elements and metabolites in maize plant tissues, by using mixtures of various proportions of NaCl, NaHCO 3 , Na 2 SO 4 , and Na 2 CO 3 . We found that alkaline salt stress suppressed more pronouncedly the photosynthesis and growth of maize plants than salinity stress. Under alkaline salt stress conditions, metal ions formed massive precipitates, which ultimately reduced plant nutrient availability. On the other hand, high neutral salt stress induced metabolic changes in the direction of gluconeogenesis leading to the enhanced formation of sugars as a reaction contributing to the mitigation of osmotic stress. Thus, the active synthesis of sugars in shoots was essential to the development of salt tolerance. However, the alkaline salt stress conditions characterized by elevated pH values suppressed substantially the levels of photosynthesis, N metabolism, glycolysis, and the production of sugars and amino acids. These results indicate the presence of different defensive mechanisms responsible for the plant responses to neutral salt and alkaline salt stresses. In addition, the increased concentration of organic acids and enhanced metabolic energy might be potential major factors that can contribute to the maintenance intracellular ion balance in maize plants and counteract the negative effects of high pH under alkaline salt stress.
Grant, Peadar F; Lowery, Madeleine M
2013-07-01
A new model of deep brain stimulation (DBS) is presented that integrates volume conduction effects with a neural model of pathological beta-band oscillations in the cortico-basal ganglia network. The model is used to test the clinical hypothesis that closed-loop control of the amplitude of DBS may be possible, based on the average rectified value of beta-band oscillations in the local field potential. Simulation of closed-loop high-frequency DBS was shown to yield energy savings, with the magnitude of the energy saved dependent on the strength of coupling between the subthalamic nucleus and the remainder of the cortico-basal ganglia network. When closed-loop DBS was applied to a strongly coupled cortico-basal ganglia network, the stimulation energy delivered over a 480 s period was reduced by up to 42%. Greater energy reductions were observed for weakly coupled networks, as the stimulation amplitude reduced to zero once the initial desynchronization had occurred. The results provide support for the application of closed-loop high-frequency DBS based on electrophysiological biomarkers.
Yamashita, Takahiro; Tose, Koji; Shichida, Yoshinori
2008-01-01
G protein-coupled receptors (GPCRs) are classified into several families based on their amino acid sequences. In family 1, GPCRs such as rhodopsin and adrenergic receptor, the structure-function relationship has been extensively investigated to demonstrate that exposure of the third cytoplasmic loop is essential for selective G protein activation. In contrast, much less is known about other families. Here we prepared chimeric mutants between Gt-coupled rhodopsin and Gi/Go- and Gs-coupled glucagon-like peptide-1 (GLP-1) receptor of family 2 and tried to identify the loop region that functions at the third cytoplasmic loop position of rhodopsin. We succeeded in expressing a mutant having the first cytoplasmic loop of GLP-1 receptor and found that this mutant activated Gi and Go efficiently but did not activate Gt. Moreover, the rhodopsin mutant having the first loop of Gs-coupled secretin receptor of family 2 decreased the Gi and Go activation efficiencies. Therefore, the first loop of GLP-1 receptor would share a similar role to the third loop of rhodopsin in G protein activation. This result strongly suggested that different families of GPCRs have maintained molecular architectures of their ancestral types to generate a common mechanism, namely exposure of the cytoplasmic loop, to activate peripheral G protein.
Tian, Yunhong; Tian, Yunming; Luo, Xiaojun; Zhou, Tao; Huang, Zuoping; Liu, Ying; Qiu, Yihan; Hou, Bing; Sun, Dan; Deng, Hongyu; Qian, Shen; Yao, Kaitai
2014-09-03
MicroRNAs (miRNAs) are a new class of endogenous regulators of a broad range of physiological processes, which act by regulating gene expression post-transcriptionally. The brassica vegetable, broccoli (Brassica oleracea var. italica), is very popular with a wide range of consumers, but environmental stresses such as salinity are a problem worldwide in restricting its growth and yield. Little is known about the role of miRNAs in the response of broccoli to salt stress. In this study, broccoli subjected to salt stress and broccoli grown under control conditions were analyzed by high-throughput sequencing. Differential miRNA expression was confirmed by real-time reverse transcription polymerase chain reaction (RT-PCR). The prediction of miRNA targets was undertaken using the Kyoto Encyclopedia of Genes and Genomes (KEGG) Orthology (KO) database and Gene Ontology (GO)-enrichment analyses. Two libraries of small (or short) RNAs (sRNAs) were constructed and sequenced by high-throughput Solexa sequencing. A total of 24,511,963 and 21,034,728 clean reads, representing 9,861,236 (40.23%) and 8,574,665 (40.76%) unique reads, were obtained for control and salt-stressed broccoli, respectively. Furthermore, 42 putative known and 39 putative candidate miRNAs that were differentially expressed between control and salt-stressed broccoli were revealed by their read counts and confirmed by the use of stem-loop real-time RT-PCR. Amongst these, the putative conserved miRNAs, miR393 and miR855, and two putative candidate miRNAs, miR3 and miR34, were the most strongly down-regulated when broccoli was salt-stressed, whereas the putative conserved miRNA, miR396a, and the putative candidate miRNA, miR37, were the most up-regulated. Finally, analysis of the predicted gene targets of miRNAs using the GO and KO databases indicated that a range of metabolic and other cellular functions known to be associated with salt stress were up-regulated in broccoli treated with salt. A comprehensive
NASA Astrophysics Data System (ADS)
Opolski, Antoni
2014-12-01
Professor Antoni Opolski was actively interested in astronomy after his retirement in 1983. He especially liked to study the works of the famous astronomer Copernicus getting inspiration for his own work. Opolski started his work on planetary loops in 2011 continuing it to the end of 2012 . During this period calculations, drawings, tables, and basic descriptions of all the planets of the Solar System were created with the use of a piece of paper and a pencil only. In 2011 Antoni Opolski asked us to help him in editing the manuscript and preparing it for publication. We have been honored having the opportunity to work on articles on planetary loops with Antoni Opolski in his house for several months. In the middle of 2012 the detailed material on Jupiter was ready. However, professor Opolski improved the article by smoothing the text and preparing new, better drawings. Finally the article ''Loops of Jupiter'', written by the 99- year old astronomer, was published in the year of his 100th birthday.
Closed loop models for analyzing engineering requirements for simulators
NASA Technical Reports Server (NTRS)
Baron, S.; Muralidharan, R.; Kleinman, D.
1980-01-01
A closed loop analytic model, incorporating a model for the human pilot, (namely, the optimal control model) that would allow certain simulation design tradeoffs to be evaluated quantitatively was developed. This model was applied to a realistic flight control problem. The resulting model is used to analyze both overall simulation effects and the effects of individual elements. The results show that, as compared to an ideal continuous simulation, the discrete simulation can result in significant performance and/or workload penalties.
NASA Technical Reports Server (NTRS)
Thomas, Jr., Jess B. (Inventor)
1991-01-01
An improved digital phase lock loop incorporates several distinctive features that attain better performance at high loop gain and better phase accuracy. These features include: phase feedback to a number-controlled oscillator in addition to phase rate; analytical tracking of phase (both integer and fractional cycles); an amplitude-insensitive phase extractor; a more accurate method for extracting measured phase; a method for changing loop gain during a track without loss of lock; and a method for avoiding loss of sampled data during computation delay, while maintaining excellent tracking performance. The advantages of using phase and phase-rate feedback are demonstrated by comparing performance with that of rate-only feedback. Extraction of phase by the method of modeling provides accurate phase measurements even when the number-controlled oscillator phase is discontinuously updated.
NASA Astrophysics Data System (ADS)
Schmatz, Joyce; Urai, Janos L.; Wübbeler, Franziska M. M.; Sadler, Marc
2014-05-01
It has been shown that dilatant deformation promotes the incorporation of hydrocarbons into typically low permeable rock salt (Schoenherr et al., 2007). However, there is not much knowledge on subsequent mechanisms related to recrystallization processes, which cause morphological and chemical changes of the carbonic inclusions. This work aims to contribute to an increased understanding of fluid inclusion dynamics related to grain boundary migration recrystallization and hence to facilitate the interpretation of complex microstructures in recrystallized, multiphase salt rocks. In this case study we investigate hydrocarbon-impregnated salt from the Cambrian Ara Group in the South Oman Salt Basin. The samples were cored from cm-m thick anhydrite-salt sequences overlying hydrocarbon bearing carbonate stringers in 3300 m depth. The anhydrite layers consist mainly of fine-grained anhydrite, which contains calcite, dolomite, and olivine inclusions. Solid bitumen and lighter hydrocarbon phases are observed in between the anhydrite grains and along cracks. Anhydrite layers host salt veins, which contain fragments of anhydrite. These fragments do not differ in composition or structure from the host material and the related vein microstructures indicate crack-seal mechanisms. Halite in the salt layers is almost entirely recrystallized with solid inclusions consisting of anhydrite, calcite, dolomite and olivine with hydrocarbon-coatings present inside grains and along grain boundaries. Solid inclusions cause pinning indicated by a decreased recrystallized grain size and by the presence of grains with preserved substructures representing earlier deformation phases. We observe two types of carbonic inclusions: I) solid bitumen coatings along grain boundaries and microcracks, interpreted to be incorporated into the salt in an overpressure state that allowed dilatancy of the salt, and II) less degraded, liquid hydrocarbons along grain boundaries in the vicinity of the anhydrite
de Abreu, Carlos Eduardo Braga; Araújo, Gyedre dos Santos; Monteiro-Moreira, Ana Cristina de Oliveira; Costa, José Hélio; Leite, Hugo de Brito; Moreno, Frederico Bruno Mendes Batista; Prisco, José Tarquinio; Gomes-Filho, Enéas
2014-08-01
Cowpea cultivars differing in salt tolerance reveal differences in protein profiles and adopt different strategies to overcome salt stress. Salt-tolerant cultivar shows induction of proteins related to photosynthesis and energy metabolism. Salinity is a major abiotic stress affecting plant cultivation and productivity. The objective of this study was to examine differential proteomic responses to salt stress in leaves of the cowpea cultivars Pitiúba (salt tolerant) and TVu 2331 (salt sensitive). Plants of both cultivars were subjected to salt stress (75 mM NaCl) followed by a recovery period of 5 days. Proteins extracted from leaves of both cultivars were analyzed by two-dimensional electrophoresis (2-DE) under salt stress and after recovery. In total, 22 proteins differentially regulated by both salt and recovery were identified by LC-ESI-MS/MS. Our current proteome data revealed that cowpea cultivars adopted different strategies to overcome salt stress. For the salt-tolerant cultivar (Pitiúba), increase in abundance of proteins involved in photosynthesis and energy metabolism, such as rubisco activase, ribulose-5-phosphate kinase (Ru5PK) (EC 2.7.1.19), glycine decarboxylase (EC 1.4.4.2) and oxygen-evolving enhancer (OEE) protein 2, was observed. However, these vital metabolic processes were more profoundly affected in salt-sensitive cultivar (TVu), as indicated by the down-regulation of OEE protein 1, Mn-stabilizing protein-II, carbonic anhydrase (EC 4.2.1.1) and Rubisco (EC 4.1.1.39), leading to energy reduction and a decline in plant growth. Other proteins differentially regulated in both cultivars corresponded to different physiological responses. Overall, our results provide information that could lead to a better understanding of the molecular basis of salt tolerance and sensitivity in cowpea plants.
Pore-scale dynamics of salt transport in drying porous media
NASA Astrophysics Data System (ADS)
Shokri, N.
2013-12-01
Understanding the physics of water evaporation from saline porous media is important in many hydrological processes such as land-atmosphere interactions, water management, vegetation, soil salinity, and mineral-fluid interactions. We applied synchrotron x-ray micro-tomography to investigate the pore-scale dynamics of dissolved salt distribution in a three dimensional drying saline porous media using a cylindrical plastic column (15 mm in height and 8 mm in diameter) packed with sand particles saturated with CaI2 solution (5% concentration by mass) with a spatial and temporal resolution of 12 microns and 30 min, respectively. Every time the drying sand column was set to be imaged, two different images were recorded using distinct synchrotron X-rays energies immediately above (33.2690 keV) and below (33.0690 keV) the K-edge value of Iodine (33.1694 keV). Taking the difference between pixel gray values enabled us to delineate the spatial and temporal distribution of CaI2 concentration at pore scale. The experiment was continued for 12 hours. Results indicate that during early stages of evaporation, air preferentially invades large pores at the surface while finer pores remain saturated and connected to the wet zone at bottom via capillary-induced liquid flow. Consequently, the salt concentration increases preferentially in finer pores where evaporation occurs. The Peclet number (describing the competition between convection and diffusion) was greater than one in our experiment resulting in higher salt concentrations closer to the evaporation surface indicating a convection-driven process. The obtained salt profiles were used to evaluate the numerical solution of the convection-diffusion equation (CDE). Results show that the macro-scale CDE could capture the overall trend of the measured salt profiles but fail to produce the exact slope of the profiles. Our results shed new insight on the physics of salt transport and its complex dynamics in drying porous media and
NASA Technical Reports Server (NTRS)
Lulla, Kamlesh P.; Helfert, Michael R.
1989-01-01
Sambhar Salt Lake is the largest salt lake (230 sq km) in India, situated in the northwest near Jaipur. Analysis of Space Shuttle photographs of this ephemeral lake reveals that water levels and lake basin land-use information can be extracted by both the digital and manual analysis techniques. Seasonal characteristics captured by the two Shuttle photos used in this study show that additional land use/cover categories can be mapped from the dry season photos. This additional information is essential for precise cartographic updates, and provides seasonal hydrologic profiles and inputs for potential mesoscale climate modeling. This paper extends the digitization and mensuration techniques originally developed for space photography and applied to other regions (e.g., Lake Chad, Africa, and Great Salt Lake, USA).
Production of chlorine from chloride salts
Rohrmann, Charles A.
1981-01-01
A process for converting chloride salts and sulfuric acid to sulfate salts and elemental chlorine is disclosed. A chloride salt and sulfuric acid are combined in a furnace where they react to produce a sulfate salt and hydrogen chloride. Hydrogen chloride from the furnace contacts a molten salt mixture containing an oxygen compound of vanadium, an alkali metal sulfate and an alkali metal pyrosulfate to recover elemental chlorine. In the absence of an oxygen-bearing gas during the contacting, the vanadium is reduced, but is regenerated to its active higher valence state by separately contacting the molten salt mixture with an oxygen-bearing gas.
Loop-quantum-gravity vertex amplitude.
Engle, Jonathan; Pereira, Roberto; Rovelli, Carlo
2007-10-19
Spin foam models are hoped to provide the dynamics of loop-quantum gravity. However, the most popular of these, the Barrett-Crane model, does not have the good boundary state space and there are indications that it fails to yield good low-energy n-point functions. We present an alternative dynamics that can be derived as a quantization of a Regge discretization of Euclidean general relativity, where second class constraints are imposed weakly. Its state space matches the SO(3) loop gravity one and it yields an SO(4)-covariant vertex amplitude for Euclidean loop gravity.
THE CORONAL LOOP INVENTORY PROJECT: EXPANDED ANALYSIS AND RESULTS
DOE Office of Scientific and Technical Information (OSTI.GOV)
Schmelz, J. T.; Christian, G. M.; Chastain, R. A., E-mail: jschmelz@usra.edu
We have expanded upon earlier work that investigates the relative importance of coronal loops with isothermal versus multithermal cross-field temperature distributions. These results are important for determining if loops have substructure in the form of unresolved magnetic strands. We have increased the number of loops targeted for temperature analysis from 19 to 207 with the addition of 188 new loops from multiple regions. We selected all loop segments visible in the 171 Å images of the Atmospheric Imaging Assembly (AIA) that had a clean background. Eighty-six of the new loops were rejected because they could not be reliably separated frommore » the background in other AIA filters. Sixty-one loops required multithermal models to reproduce the observations. Twenty-eight loops were effectively isothermal, that is, the plasma emission to which AIA is sensitive could not be distinguished from isothermal emission, within uncertainties. Ten loops were isothermal. Also, part of our inventory was one small flaring loop, one very cool loop whose temperature distribution could not be constrained by the AIA data, and one loop with inconclusive results. Our survey can confirm an unexpected result from the pilot study: we found no isothermal loop segments where we could properly use the 171-to-193 ratio method, which would be similar to the analysis done for many loops observed with TRACE and EIT. We recommend caution to observers who assume the loop plasma is isothermal, and hope that these results will influence the direction of coronal heating models and the effort modelers spend on various heating scenarios.« less
Study of the post-flare loops on 29 July 1973. I - Dynamics of the X-ray loops
NASA Technical Reports Server (NTRS)
Nolte, J. T.; Gerassimenko, M.; Krieger, A. S.; Petrasso, R. D.; Svestka, Z.
1979-01-01
We derive an empirical model of the X-ray emitting post-flare loops observed during the decay phase of the 29 July 1973 flare. We find that the loops are elliptical, with the brightest emitting region at the tops. We determine the height, velocity of growth, and ratio of height to width of the loops at times from 3 to 12 hr after the flare onset.
Loop diuretics inhibit cholinergic and noncholinergic nerves in guinea pig airways.
Elwood, W; Lötvall, J O; Barnes, P J; Chung, K F
1991-06-01
Furosemide, a loop diuretic, is known to inhibit the response to a variety of indirect bronchial challenges in humans but does not inhibit bronchoconstriction induced by inhaled methacholine or histamine. We have investigated the effects of the two loop diuretics, furosemide (10(-6) to 10(-3) M) and bumetanide (10(-7) to 10(-4) M), on airway smooth muscle contraction in vitro induced by electrical field stimulation (EFS), or exogenously applied acetylcholine (ACh) or substance P (SP) in guinea pig tracheal and bronchial smooth muscle strips pretreated with indomethacin (10(-5) M) and propranolol (10(-6) M). Both furosemide and bumetanide caused a concentration-dependent inhibition of cholinergically mediated neural contraction in the trachea. The effect of furosemide was not influenced by the presence of airway epithelium. Furthermore, both furosemide and bumetanide inhibited in a concentration-dependent fashion nonadrenergic, noncholinergic (NANC) contraction induced by electrical field stimulation of bronchi pretreated with atropine (10(-5) M). Neither drug at the highest concentration inhibited the responses to exogenous acetylcholine (10(-8) to 10(-2) M) or substance P (10(-9) to 10(-5) M). Thus loop diuretics inhibit the neurally induced contraction of guinea pig airways without a direct effect on airway smooth muscle. We conclude that loop diuretics inhibit both cholinergic and excitatory NANC neurotransmission in guinea pig airways and that this effect may be related to their inhibitory effects on the sodium-potassium-chloride cotransporter.
Diverse Microhabitats Experienced by Halomonas variabilis on Salt-Secreting Leaves
Burch, Adrien Y.; Finkel, Omri M.; Cho, Juliana K.; Belkin, Shimshon
2013-01-01
The leaf surfaces of the salt-excreting tree Tamarix aphylla harbor a wide diversity of halophilic microorganisms, including Halomonas sp., but little is known of the factors that shape community composition in this extreme habitat. We isolated a strain of Halomonas variabilis from the leaf surface of T. aphylla and used it to determine the heterogeneity of salt concentrations experienced by bacteria in this environment. This halophilic strain was transformed with a proU::gfp reporter gene fusion, the fluorescence of which was responsive to NaCl concentrations up to 200 g liter−1. These bioreporting cells were applied to T. aphylla leaves and were subsequently recovered from dew droplets adhering to the leaf surface. Although cells from within a given dew droplet exhibited similar green fluorescent protein fluorescence, the fluorescence intensity varied between droplets and was correlated with the salt concentration measured in each drop. Growth of H. variabilis was observed in all droplets, regardless of the salt concentration. However, cells found in desiccated microniches between dew drops were low in abundance and generally dead. Other bacteria recovered from T. aphylla displayed higher desiccation tolerance than H. variabilis, both in culture and on inoculated plants, despite having lower osmotic tolerance. Thus, the Tamarix leaf surface can be described as a salty desert with occasional oases where water droplets form under humid conditions. While halotolerant bacteria such as Halomonas grow in high concentrations of salt in such wet microniches, other organisms are better suited to survive desiccation in sites that are not wetted. PMID:23160133
Salt-Sensitive Hypertension: Perspectives on Intrarenal Mechanisms
Majid, Dewan S.A.; Prieto, Minolfa C.; Navar, L Gabriel
2015-01-01
Salt sensitive hypertension is characterized by increases in blood pressure in response to increases in dietary salt intake and is associated with an enhanced risk of cardiovascular and renal morbidity. Although researchers have sought for decades to understand how salt sensitivity develops in humans, the mechanisms responsible for the increases in blood pressure in response to high salt intake are complex and only partially understood. Until now, scientists have been unable to explain why some individuals are salt sensitive and others are salt resistant. Although a central role for the kidneys in the development of salt sensitivity and hypertension has been generally accepted, it is also recognized that hypertension is of multifactorial origin and a variety of factors can induce, or prevent, blood pressure responsiveness to the manipulation of salt intake. Excess salt intake in susceptible persons may also induce inappropriate central and sympathetic nervous system responses and increase the production of intrarenal angiotensin II, catecholamines and other factors such as oxidative stress and inflammatory cytokines. One key factor is the concomitant inappropriate or paradoxical activation of the intrarenal renin-angiotensin system, by high salt intake. This is reflected by the increases in urinary angiotensinogen during high salt intake in salt sensitive models. A complex interaction between neuroendocrine factors and the kidney may underlie the propensity for some individuals to retain salt and develop salt-dependent hypertension. In this review, we focus mainly on the renal contributions that provide the mechanistic link between chronic salt intake and the development of hypertension. PMID:26028244
A simple second-order digital phase-locked loop.
NASA Technical Reports Server (NTRS)
Tegnelia, C. R.
1972-01-01
A simple second-order digital phase-locked loop has been designed for the Viking Orbiter 1975 command system. Excluding analog-to-digital conversion, implementation of the loop requires only an adder/subtractor, two registers, and a correctable counter with control logic. The loop considers only the polarity of phase error and corrects system clocks according to a filtered sequence of this polarity. The loop is insensitive to input gain variation, and therefore offers the advantage of stable performance over long life. Predictable performance is guaranteed by extreme reliability of acquisition, yet in the steady state the loop produces only a slight degradation with respect to analog loop performance.
Study of the post-flare loops on 29 July 1973. II - Physical parameters in the X-ray loops
NASA Technical Reports Server (NTRS)
Petrasso, R. D.; Nolte, J. T.; Gerassimenko, M.; Krieger, A. S.; Krogstad, R.; Seguin, F. H.; Svestka, Z.
1979-01-01
We use the filter ratio method of analysis to determine spatially resolved values of plasma parameters in the X-ray emitting post-flare loop system which developed on 29 and 30 July 1973. We find that the loops were hotter and had higher plasma pressure at their tops than near their footpoints. The loop tops were at nearly the same temperature at different places 3 hr after the flare maximum and were also at nearly this same temperature 3 and 8 hr later. Variations in brightness transverse to the loops were due to variations in emission measure. We show by consideration of radiative losses alone that energy must have been added to the hottest part of the flare, at the tops of the loops, late in the decay phase of the flare.
NASA Astrophysics Data System (ADS)
Clausen, O. R.; Egholm, D. L.; Wesenberg, R.
2012-04-01
Salt deformation has been the topic of numerous studies through the 20th century and up until present because of the close relation between commercial hydrocarbons and salt structure provinces of the world (Hudec & Jackson, 2007). The fault distribution in sediments above salt structures influences among other things the productivity due to the segmentation of the reservoir (Stewart 2006). 3D seismic data above salt structures can map such fault patterns in great detail and studies have shown that a variety of fault patterns exists. Yet, most patterns fall between two end members: concentric and radiating fault patterns. Here we use a modified version of the numerical spring-slider model introduced by Malthe-Sørenssen et al.(1998a) for simulating the emergence of small scale faults and fractures above a rising salt structure. The three-dimensional spring-slider model enables us to control the rheology of the deforming overburden, the mechanical coupling between the overburden and the underlying salt, as well as the kinematics of the moving salt structure. In this presentation, we demonstrate how the horizontal component on the salt motion influences the fracture patterns within the overburden. The modeling shows that purely vertical movement of the salt introduces a mesh of concentric normal faults in the overburden, and that the frequency of radiating faults increases with the amount of lateral movements across the salt-overburden interface. The two end-member fault patterns (concentric vs. radiating) can thus be linked to two different styles of salt movement: i) the vertical rising of a salt indenter and ii) the inflation of a 'salt-balloon' beneath the deformed strata. The results are in accordance with published analogue and theoretical models, as well as natural systems, and the model may - when used appropriately - provide new insight into how the internal dynamics of the salt in a structure controls the generation of fault patterns above the structure. The
Bile salts as semiochemicals in fish
Buchinger, Tyler J.; Li, Weiming; Johnson, Nicholas S.
2014-01-01
Bile salts are potent olfactory stimuli in fishes; however the biological functions driving such sensitivity remain poorly understood. We provide an integrative review of bile salts as semiochemicals in fish. First, we present characteristics of bile salt structure, metabolism, and function that are particularly relevant to chemical communication. Bile salts display a systematic pattern of structural variation across taxa, are efficiently synthesized, and are stable in the environment. Bile salts are released into the water via the intestine, urinary tract, or gills, and are highly water soluble. Second, we consider the potential role of bile salts as semiochemicals in the contexts of detecting nearby fish, foraging, assessing risk, migrating, and spawning. Lastly, we suggest future studies on bile salts as semiochemicals further characterize release into the environment, behavioral responses by receivers, and directly test the biological contexts underlying olfactory sensitivity.
Binary phase locked loops for Omega receivers
NASA Technical Reports Server (NTRS)
Chamberlin, K.
1974-01-01
An all-digital phase lock loop (PLL) is considered because of a number of problems inherent in an employment of analog PLL. The digital PLL design presented solves these problems. A single loop measures all eight Omega time slots. Memory-aiding leads to the name of this design, the memory-aided phase lock loop (MAPLL). Basic operating principles are discussed and the superiority of MAPLL over the conventional digital phase lock loop with regard to the operational efficiency for Omega applications is demonstrated.
NASA Technical Reports Server (NTRS)
Lee, Kimyeong; Holman, Richard; Kolb, Edward W.
1987-01-01
Wilson-loop symmetry breaking is considered on a space-time of the form M4 x K, where M4 is a four-dimensional space-time and K is an internal space with nontrivial and finite fundamental group. It is shown in a simple model that the different vacua obtained by breaking a non-Abelian gauge group by Wilson loops are separated in the space of gauge potentials by a finite energy barrier. An interpolating gauge configuration is then constructed between these vacua and shown to have minimum energy. Finally some implications of this construction are discussed.
Webster, Jacqui; Dunford, Elizabeth; Barzi, Federica; Neal, Bruce
2010-02-01
Australians currently consume too much salt causing adverse consequences for health. The media play an important role in the provision of nutrition advice to consumers. Previous research shows that many foods advertized in consumer magazines are high in salt, but little research has examined magazine recipes in this context. The aim of this project was to summarize directions for salt use in recipes in leading Australian magazines. In August 2007 and 2008, the top 10 magazines by circulation that included at least five recipes, were examined. Standardized information was collected about directions for salt use in recipes. Three hundred and thirty recipes were identified in 2007 and 417 in 2008. About 68% of recipes included high-salt ingredients, 37% instructed to season with salt, 10% instructed to add a specific quantity of salt and 15% recommended selection of low-salt ingredients. There was substantial variability in directions for salt use in recipes between magazines, but no clear differences between 2007 and 2008. Many recipes advised to add salt in direct contradiction to national dietary guidelines. There is clear potential for editorial guidelines on salt use in recipes to play a role in advancing public health efforts in Australia and other such nations.
Mohammad, Sultan; Schleinitz, Miko; Coutinhoa, João A. P.; Freire, Mara G.
2016-01-01
Due to scarce available experimental data, as well as due to the absence of predictive models, the influence of salts on the solubility of ionic liquids (ILs) in water is still poorly understood. To this end, this work addresses the solubility of the IL 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([C4C1im][NTf2]), at 298.15 K and 0.1 MPa, in aqueous salt solutions (from 0.1 to 1.5 mol kg−1). At salt molalities higher than 0.2 mol kg−1, all salts caused salting-out of [C4C1im][NTf2] from aqueous solution with their strength decreasing in the following order: Al2(SO4)3 > ZnSO4 > K3C6H5O7 > KNaC4H4O6 > K3PO4 > Mg(CH3CO2)2 > K2HPO4 > MgSO4 > KH2PO4 > KCH3CO2. Some of these salts lead however to the salting-in of [C4C1im][NTf2] in aqueous medium at salt molalities lower than 0.20 mol kg−1. To attempt the development of a model able to describe the salt effects, comprising both the salting-in and salting-out phenomena observed, the electrolyte Perturbed-Chain Statistical Associating Fluid Theory (ePC-SAFT) was applied using ion-specific parameters. The gathered experimental data was modelled using ePC-SAFT parameters complemented by fitting a single binary parameter between K+ and the IL-ions to the IL solubility in K3PO4 aqueous solutions. Based on this approach, the description of anion-specific salting-out effects of the remaining potassium salts was found to be in good agreement with experimental data. Remarkably, ePC-SAFT is even able to predict the salting-in effect induced by K2HPO4, based on the single K+/IL-ions binary parameter which was fitted to an exclusively salting-out effect promoted by K3PO4. Finally, ePC-SAFT was applied to predict the influence of other sodium salts on the [C4C1im][NTf2] solubility in water, with experimental data taken from literature, leading to an excellent description of the liquid–liquid phase behaviour. PMID:26575280
Loop quantum cosmology and singularities.
Struyve, Ward
2017-08-15
Loop quantum gravity is believed to eliminate singularities such as the big bang and big crunch singularity. This belief is based on studies of so-called loop quantum cosmology which concerns symmetry-reduced models of quantum gravity. In this paper, the problem of singularities is analysed in the context of the Bohmian formulation of loop quantum cosmology. In this formulation there is an actual metric in addition to the wave function, which evolves stochastically (rather than deterministically as the case of the particle evolution in non-relativistic Bohmian mechanics). Thus a singularity occurs whenever this actual metric is singular. It is shown that in the loop quantum cosmology for a homogeneous and isotropic Friedmann-Lemaître-Robertson-Walker space-time with arbitrary constant spatial curvature and cosmological constant, coupled to a massless homogeneous scalar field, a big bang or big crunch singularity is never obtained. This should be contrasted with the fact that in the Bohmian formulation of the Wheeler-DeWitt theory singularities may exist.
NASA Technical Reports Server (NTRS)
2002-01-01
Salt Lake City, Utah, will host the 2002 Winter Olympic Games. The city is located on the southeastern shore of the Great Salt Lake and sits to the west of the Wasatch Mountains, which rise more than 3,500 meters (10,000 feet) above sea level. The city was first settled in 1847 by pioneers seeking relief from religious persecution. Today Salt Lake City, the capital of Utah, is home to more than 170,000 residents. This true-color image of Salt Lake City was acquired by the Enhanced Thematic Mapper Plus (ETM+), flying aboard Landsat 7, on May 26, 2000. The southeastern tip of the Great Salt Lake is visible in the upper left of the image. The furrowed green and brown landscape running north-south is a portion of the Wasatch Mountains, some of which are snow-capped (white pixels). The greyish pixels in the center of the image show the developed areas of the city. A number of water reservoirs can be seen east of the mountain range. Salt Lake City International Airport is visible on the northwestern edge of the city. About 20 miles south of the airport is the Bingham Canyon Copper Mine (tan pixels), the world's largest open pit excavation. See also this MODIS image of Utah. Image courtesy NASA Landsat7 Science Team and USGS Eros Data Center
Some new results for the one-loop mass correction to the compactified λϕ4 theory
NASA Astrophysics Data System (ADS)
Fucci, Guglielmo; Kirsten, Klaus
2018-03-01
In this work, we consider the one-loop effective action of a self-interacting λϕ4 field propagating in a D dimensional Euclidean space endowed with d ≤ D compact dimensions. The main purpose of this paper is to compute the corrections to the mass of the field due to the presence of the compactified dimensions. Although the results of the one-loop correction to the mass of a λϕ4 field are very well known for compactified toroidal spaces, where the field obeys periodic boundary conditions, similar results do not appear to be readily available for cases in which the scalar field is subject to Dirichlet and Neumann boundary conditions. We apply the results of the one-loop mass correction to the study of the critical temperature in Ginzburg-Landau models.
Statistical Characteristic of Global Tropical Cyclone Looping Motion
NASA Astrophysics Data System (ADS)
Shen, W.; Song, J.; Wang, Y.
2016-12-01
Statistical characteristic of looping motion of tropical cyclones (TCs) in the Western North Pacific (WPAC), North Atlantic (NATL), Eastern North Pacific (EPAC), Northern Indian Ocean (NIO), Southern Indian Ocean (SIO) and South Pacific (SPAC) basins are investigated by using IBTrACS archive maintained by NOAA. From global perspective, about ten percent TCs experience a looping motion in the above six basins. The southern hemisphere (SH) including SIO and SPAC basins have higher looping percentage than the northern hemisphere (NH), while the EPAC basin has the least looping percentage. The interannual variation of the number of looping TCs are significantly correlated with that of total TCs in the NATL, SIO and SPAC basins, while there are no correlations between the EPAC and NIO basins. The numbers of looping TCs have a higher percentage in the early and late cyclone season in the NH rather than the peak period of cyclone season, while the SIO and SPAC basins have the higher looping percentage in the early and late cyclone season, respectively. The looping motion of TCs mainly concentrates on the scale of tropical depression to category 2 and has its peak value on the scale of tropical storm. The looping motion appears more frequently and has a higher percentage at the pre-mature stage than the post-mature stage of TCs in most basins except EPAC. Comparing the intensity and intensity variation caused by the looping motion, the weaker TCs tend to intensify after looping, while the more intense ones weaken.
Dislocation loop models for the high temperature creep of Al-5.5 at.% Mg alloy
DOE Office of Scientific and Technical Information (OSTI.GOV)
An, S.U.; Blum, W.
1995-04-15
The Al-5.5 at.% Mg alloy is a typical class I type solution hardened material. The dislocation loop models proposed by Orlova and Cadek and by Mills et al., respectively are widely applied models in describing the high temperature creep behavior of the Al-5.5 at.% Mg alloy. These models, however, are in conflict in explaining dislocation loop theory. Orlova and Cadek suggest that in class I solution hardened alloys screw dislocations are relatively easier to migrate because they are subject to a smaller resistance in motion than edge dislocations. Consequently, the migration rate of screw dislocations is higher than that ofmore » edge dislocations. However, since dislocation loops are composed of both screw and edge components, the overall migration rate of screw dislocations are reduced by that of the edge component. Mills et al. on the contrary, used a different dislocation loop model. As the loop grows while it moves, it takes on the shape of an ellipsoid due to the unbalance in growth rate, the score segment moving much easier than the edge. Therefore, as shown in the results of the stress reduction tests, rapid elastic ({Delta} {var_epsilon}{sub el}) and anelastic contraction ({Delta} {var_epsilon}{sub an}) occur simultaneously directly after stress reduction. During the movement of the dislocation loop, the screw component hence becomes severely curved, while the edge component retains a straight line. This has been proved through dislocation structure observations by TEM.« less
Space Station evolution study oxygen loop closure
NASA Technical Reports Server (NTRS)
Wood, M. G.; Delong, D.
1993-01-01
In the current Space Station Freedom (SSF) Permanently Manned Configuration (PMC), physical scars for closing the oxygen loop by the addition of oxygen generation and carbon dioxide reduction hardware are not included. During station restructuring, the capability for oxygen loop closure was deferred to the B-modules. As such, the ability to close the oxygen loop in the U.S. Laboratory module (LAB A) and the Habitation A module (HAB A) is contingent on the presence of the B modules. To base oxygen loop closure of SSF on the funding of the B-modules may not be desirable. Therefore, this study was requested to evaluate the necessary hooks and scars in the A-modules to facilitate closure of the oxygen loop at or subsequent to PMC. The study defines the scars for oxygen loop closure with impacts to cost, weight and volume and assesses the effects of byproduct venting. In addition, the recommended scenarios for closure with regard to topology and packaging are presented.
Alleviation of salt stress in lemongrass by salicylic acid.
Idrees, Mohd; Naeem, M; Khan, M Nasir; Aftab, Tariq; Khan, M Masroor A; Moinuddin
2012-07-01
Soil salinity is one of the key factors adversely affecting the growth, yield, and quality of crops. A pot study was conducted to find out whether exogenous application of salicylic acid could ameliorate the adverse effect of salinity in lemongrass (Cymbopogon flexuosus Steud. Wats.). Two Cymbopogon varieties, Krishna and Neema, were used in the study. Three salinity levels, viz, 50, 100, and 150 mM of NaCl, were applied to 30-day-old plants. Salicylic acid (SA) was applied as foliar spray at 10(-5) M concentration. Totally, six SA-sprays were carried out at 10-day intervals, following the first spray at 30 days after sowing. The growth parameters were progressively reduced with the increase in salinity level; however, growth inhibition was significantly reduced by the foliar application of SA. With the increase in salt stress, a gradual decrease in the activities of carbonic anhydrase and nitrate reductase was observed in both the varieties. SA-treatment not only ameliorated the adverse effects of NaCl but also showed a significant improvement in the activities of these enzymes compared with the untreated stressed-plants. The plants supplemented with NaCl exhibited a significant increase in electrolyte leakage, proline content, and phosphoenol pyruvate carboxylase activity. Content and yield of essential oil was also significantly decreased in plants that received salinity levels; however, SA overcame the unfavorable effects of salinity stress to a considerable extent. Lemongrass variety Krishna was found to be more adapted to salt stress than Neema, as indicated by the overall performance of the two varieties under salt conditions.
Closed-Loop Neuromorphic Benchmarks
Stewart, Terrence C.; DeWolf, Travis; Kleinhans, Ashley; Eliasmith, Chris
2015-01-01
Evaluating the effectiveness and performance of neuromorphic hardware is difficult. It is even more difficult when the task of interest is a closed-loop task; that is, a task where the output from the neuromorphic hardware affects some environment, which then in turn affects the hardware's future input. However, closed-loop situations are one of the primary potential uses of neuromorphic hardware. To address this, we present a methodology for generating closed-loop benchmarks that makes use of a hybrid of real physical embodiment and a type of “minimal” simulation. Minimal simulation has been shown to lead to robust real-world performance, while still maintaining the practical advantages of simulation, such as making it easy for the same benchmark to be used by many researchers. This method is flexible enough to allow researchers to explicitly modify the benchmarks to identify specific task domains where particular hardware excels. To demonstrate the method, we present a set of novel benchmarks that focus on motor control for an arbitrary system with unknown external forces. Using these benchmarks, we show that an error-driven learning rule can consistently improve motor control performance across a randomly generated family of closed-loop simulations, even when there are up to 15 interacting joints to be controlled. PMID:26696820
NASA Astrophysics Data System (ADS)
Ferrer, Oriol; Vidal-Royo, Oskar; Gratacós, Oscar; Roca, Eduard; Muñoz, Josep Anton; Esestime, Paolo; Rodriguez, Karyna; Yazmin Piragauta, Mary; Feliu, Nil
2017-04-01
The presence of a thick Messinian evaporite unit is a well known feature of the Mediterranean basins. This salt unit is composed of three sub-units (Lower, Mobile and Upper Units) in the Northwest Mediterranean. In contrast, in the Eastern Mediterranean it is characterized by a multilayered evaporite sequence. In both regions the salt acted as a detachment favoring the downslope gravitational failure of the overlying sediments in a thin-skinned deformation regime (e.g. Liguro-Provençal or Levant basins). As a result, these salt-bearing passive margins exhibit the classical three-domain structural zonation characterized by upslope extension, intermediate translation and downslope contraction. Nevertheless, the presence of pre-salt reliefs (e.g. irregularly eroded palaeotopography or volcanic edifices) is rather common in the translational domain of the Northwestern Mediterranean (e.g. Liguro-Provençal and West Corsica margins). In this scenario, pre-salt reliefs act as flow barriers and hinder salt drainage. When their summit lies close or above the top salt, these structures may partially or fully block salt flow. They also disrupt locally the structural zonation of the passive margin and constrain cover deformation. In contrast, in the Eastern Mediterranean the Eratosthenes seamount is characterized by a large scale submerged massif (ca. 120 km in size) that significantly influenced the structural evolution of the surrounding areas. This inherited relief acted as a buttress and deflected the Messinian salt flow constraining supra-salt deformation (e.g. Levant Basin and Nile margin). In addition, the geometry of the Eratosthenes seamount also restrained the structural style of the allochthonous salt that was expulsed during the development of the Cyprus subduction zone to the north. Using an experimental approach (sandbox models) and new analysis techniques, we investigate salt and supra-salt deformation in response to two different types of pre-salt relief: 1
Zou, Ping; Li, Kecheng; Liu, Song; He, Xiaofei; Zhang, Xiaoqian; Xing, Ronge; Li, Pengcheng
2016-04-13
In this study, sulfated chitooligosaccharide (SCOS) was applied to wheat seedlings to investigate its effect on the plants' defense response under salt stress. The antioxidant enzyme activities, chlorophyll contents, and fluorescence characters of wheat seedlings were determined at a certain time. The results showed that treatment with exogenous SCOS could decrease the content of malondialdehyde, increase the chlorophyll contents, and modulate fluorescence characters in wheat seedlings under salt stress. In addition, SCOS was able to regulate the activities of antioxidant enzymes containing superoxide dismutase, catalase, peroxidase, ascorbate peroxidase, glutathione reductase, and dehydroascorbate reductase. Similarly, the mRNA expression levels of several antioxidant enzymes were efficiently modulated by SCOS. The results indicated that SCOS could alleviate the damage of salt stress by adjusting the antioxidant enzyme activities of plant. The effect of SCOS on the photochemical efficiency of wheat seedlings was associated with its enhanced capacity for antioxidant enzymes, which prevented structure degradation of the photosynthetic apparatus under NaCl stress. Furthermore, the effective activities of alleviating salt stress indicated the activities of SCOS were closely related with the sulfate group.
Two-phase Heating in Flaring Loops
NASA Astrophysics Data System (ADS)
Zhu, Chunming; Qiu, Jiong; Longcope, Dana W.
2018-03-01
We analyze and model a C5.7 two-ribbon solar flare observed by the Solar Dynamics Observatory, Hinode, and GOES on 2011 December 26. The flare is made of many loops formed and heated successively over one and half hours, and their footpoints are brightened in the UV 1600 Å before enhanced soft X-ray and EUV missions are observed in flare loops. Assuming that anchored at each brightened UV pixel is a half flaring loop, we identify more than 6700 half flaring loops, and infer the heating rate of each loop from the UV light curve at the footpoint. In each half loop, the heating rate consists of two phases: intense impulsive heating followed by a low-rate heating that is persistent for more than 20 minutes. Using these heating rates, we simulate the evolution of their coronal temperatures and densities with the model of the “enthalpy-based thermal evolution of loops.” In the model, suppression of thermal conduction is also considered. This model successfully reproduces total soft X-ray and EUV light curves observed in 15 passbands by four instruments GOES, AIA, XRT, and EVE. In this flare, a total energy of 4.9 × 1030 erg is required to heat the corona, around 40% of this energy is in the slow-heating phase. About two-fifths of the total energy used to heat the corona is radiated by the coronal plasmas, and the other three fifth transported to the lower atmosphere by thermal conduction.
Whitecaps, sea-salt aerosols, and climate
NASA Astrophysics Data System (ADS)
Anguelova, Magdalena Dimitrova
Oceanic whitecaps are the major source of sea-salt aerosols. Because these aerosols are dominant in remote marine air, they control the radiative properties of the clean background atmosphere by scattering sunlight, changing cloud properties and lifetime, and providing media for chemical reactions. Including sea-salt effects in climate models improves predictions, but simulating their generation is first necessary. To make the sea-salt generation function currently used in climate models more relevant for aerosol investigations, this study proposes two modifications. First, the conventional relation between whitecap coverage, W, and the 10-meter wind speed, U10, used in typical generation functions is expanded to include additional factors that affect whitecaps and sea-salt aerosol formation. Second, the sea-salt generation function is extended to smaller sizes; sea-salt aerosol with initial radii from 0.4 to 20 mum can now be modeled. To achieve these goals, this thesis develops a new method for estimating whitecap coverage on a global scale using satellite measurements of the brightness temperature of the ocean surface. Whitecap coverage evaluated with this method incorporates the effects of atmospheric stability, sea-surface temperature, salinity, wind fetch, wind duration, and the amount of surface-active material. Assimilating satellite-derived values for whitecap coverage in the sea-salt generation function incorporates the effects of all environmental factors on sea-salt production and predicts realistic sea-salt aerosol loadings into the atmosphere. An extensive database of whitecap coverage and sea-salt aerosol fluxes has been compiled with the new method and is used to investigate their spatial and temporal characteristics. The composite effect of all environmental factors suggests a more uniform latitudinal distribution of whitecaps and sea-salt aerosols than that predicted from wind speed alone. The effect of sea-surface temperature, TS, is
Control-structure interaction in precision pointing servo loops
NASA Technical Reports Server (NTRS)
Spanos, John T.
1989-01-01
The control-structure interaction problem is addressed via stability analysis of a generic linear servo loop model. With the plant described by the rigid body mode and a single elastic mode, structural flexibility is categorized into one of three types: (1) appendage, (2) in-the-loop minimum phase, and (3) in-the-loop nonminimum phase. Closing the loop with proportional-derivative (PD) control action and introducing sensor roll-off dynamics in the feedback path, stability conditions are obtained. Trade studies are conducted with modal frequency, modal participation, modal damping, loop bandwidth, and sensor bandwidth treated as free parameters. Results indicate that appendage modes are most likely to produce instability if they are near the sensor rolloff, whereas in-the-loop modes are most dangerous near the loop bandwidth. The main goal of this paper is to provide a fundamental understanding of the control-structure interaction problem so that it may benefit the design of complex spacecraft and pointing system servo loops. In this framework, the JPL Pathfinder gimbal pointer is considered as an example.
Chacko, Ajay; Tikku, Tripti; Khanna, Rohit; Maurya, Rana Pratap; Srivastava, Kamna
2018-05-28
Retraction in lingual orthodontics has biomechanical differences when compared to labial orthodontics, which is not yet established. Thus, we have intended to compare the biomechanical characteristics of closed helical loop and T-loop on 1 mm activation with 30° of compensatory curvatures during retraction in lingual orthodontics. STb lingual brackets were indirectly bonded to maxillary typhodont model that was scanned to obtain FEM model. Closed helical loop (2 × 7 mm) and T-loop (6 × 2 × 7 mm) of 0.016″ × 0.016″ TMA wire were modeled without preactivation bends. Preactivation bends at 30° were given in the software. Boundary conditions were set. The force (F) and moment (M) of both the loops were determined on 1 mm activation, using ANSYS software. M/F ratio was also calculated for both the loops. T-loop exerted less force, thus increased M/F ratio as compared to closed helical loop on 1 mm activation. When torque has to be preserved in the anterior segment during retraction in lingual orthodontics, T-loop can be preferred over closed helical loop.
Effects of applied strain on nanoscale self-interstitial cluster formation in BCC iron
NASA Astrophysics Data System (ADS)
Gao, Ning; Setyawan, Wahyu; Kurtz, Richard J.; Wang, Zhiguang
2017-09-01
The effect of applied strains on the configurational evolution of self-interstitial clusters in BCC iron (Fe) is explored with atomistic simulations. A novel cluster configuration is discovered at low temperatures (<600 K), which consists of 〈 110 〉 dumbbells and 〈 111 〉 crowdions in a specific configuration, resulting in an immobile defect. The stability and diffusion of this cluster at higher temperatures is explored. In addition, an anisotropy distribution factor of a particular [ hkl ] interstitial loop within the family of 〈 hkl 〉 loops is calculated as a function of strain. The results show that loop anisotropy is governed by the angle between the stress direction and the orientation of the 〈 111 〉 crowdions in the loop, and directly linked to the stress induced preferred nucleation of self-interstitial atoms.
Effects of applied strain on nanoscale self-interstitial cluster formation in BCC iron
DOE Office of Scientific and Technical Information (OSTI.GOV)
Gao, Ning; Setyawan, Wahyu; Kurtz, Richard J.
2017-09-01
The effect of applied strains on the configurational evolution of self-interstitial clusters in BCC iron (Fe) is explored with atomistic simulations. A novel cluster configuration is discovered at low temperatures (<600 K), which consists of <110> dumbbells and <111> crowdions in a specific configuration, resulting in an immobile defect. The stability and diffusion of this cluster at higher temperatures is explored. In addition, an anisotropy distribution factor of a particular [hkl] interstitial loop within the family of loops is calculated as a function of strain. The results show that loop anisotropy is governed by the angle between the stress directionmore » and the orientation of the <111> crowdions in the loop, and directly linked to the stress induced preferred nucleation of self-interstitial atoms.« less
Real-time Electrophysiology: Using Closed-loop Protocols to Probe Neuronal Dynamics and Beyond
Linaro, Daniele; Couto, João; Giugliano, Michele
2015-01-01
Experimental neuroscience is witnessing an increased interest in the development and application of novel and often complex, closed-loop protocols, where the stimulus applied depends in real-time on the response of the system. Recent applications range from the implementation of virtual reality systems for studying motor responses both in mice1 and in zebrafish2, to control of seizures following cortical stroke using optogenetics3. A key advantage of closed-loop techniques resides in the capability of probing higher dimensional properties that are not directly accessible or that depend on multiple variables, such as neuronal excitability4 and reliability, while at the same time maximizing the experimental throughput. In this contribution and in the context of cellular electrophysiology, we describe how to apply a variety of closed-loop protocols to the study of the response properties of pyramidal cortical neurons, recorded intracellularly with the patch clamp technique in acute brain slices from the somatosensory cortex of juvenile rats. As no commercially available or open source software provides all the features required for efficiently performing the experiments described here, a new software toolbox called LCG5 was developed, whose modular structure maximizes reuse of computer code and facilitates the implementation of novel experimental paradigms. Stimulation waveforms are specified using a compact meta-description and full experimental protocols are described in text-based configuration files. Additionally, LCG has a command-line interface that is suited for repetition of trials and automation of experimental protocols. PMID:26132434
Salt bridges: geometrically specific, designable interactions.
Donald, Jason E; Kulp, Daniel W; DeGrado, William F
2011-03-01
Salt bridges occur frequently in proteins, providing conformational specificity and contributing to molecular recognition and catalysis. We present a comprehensive analysis of these interactions in protein structures by surveying a large database of protein structures. Salt bridges between Asp or Glu and His, Arg, or Lys display extremely well-defined geometric preferences. Several previously observed preferences are confirmed, and others that were previously unrecognized are discovered. Salt bridges are explored for their preferences for different separations in sequence and in space, geometric preferences within proteins and at protein-protein interfaces, co-operativity in networked salt bridges, inclusion within metal-binding sites, preference for acidic electrons, apparent conformational side chain entropy reduction on formation, and degree of burial. Salt bridges occur far more frequently between residues at close than distant sequence separations, but, at close distances, there remain strong preferences for salt bridges at specific separations. Specific types of complex salt bridges, involving three or more members, are also discovered. As we observe a strong relationship between the propensity to form a salt bridge and the placement of salt-bridging residues in protein sequences, we discuss the role that salt bridges might play in kinetically influencing protein folding and thermodynamically stabilizing the native conformation. We also develop a quantitative method to select appropriate crystal structure resolution and B-factor cutoffs. Detailed knowledge of these geometric and sequence dependences should aid de novo design and prediction algorithms. Copyright © 2010 Wiley-Liss, Inc.
NASA Astrophysics Data System (ADS)
Sandoz, J.-P.; Steenaart, W.
1984-12-01
The nonuniform sampling digital phase-locked loop (DPLL) with sequential loop filter, in which the correction sizes are controlled by the accumulated differences of two additional phase comparators, is graphically analyzed. In the absence of noise and frequency drift, the analysis gives some physical insight into the acquisition and tracking behavior. Taking noise into account, a mathematical model is derived and a random walk technique is applied to evaluate the rms phase error and the mean acquisition time. Experimental results confirm the appropriate simplifying hypotheses used in the numerical analysis. Two related performance measures defined in terms of the rms phase error and the acquisition time for a given SNR are used. These measures provide a common basis for comparing different digital loops and, to a limited extent, also with a first-order linear loop. Finally, the behavior of a modified DPLL under frequency deviation in the presence of Gaussian noise is tested experimentally and by computer simulation.
Carlacci, Louis; Millard, Charles B; Olson, Mark A
2004-10-01
The X-ray crystal structure of the reaction product of acetylcholinesterase (AChE) with the inhibitor diisopropylphosphorofluoridate (DFP) showed significant structural displacement in a loop segment of residues 287-290. To understand this conformational selection, a Monte Carlo (MC) simulation study was performed of the energy landscape for the loop segment. A computational strategy was applied by using a combined simulated annealing and room temperature Metropolis sampling approach with solvent polarization modeled by a generalized Born (GB) approximation. Results from thermal annealing reveal a landscape topology of broader basin opening and greater distribution of energies for the displaced loop conformation, while the ensemble average of conformations at 298 K favored a shift in populations toward the native by a free-energy difference in good agreement with the estimated experimental value. Residue motions along a reaction profile of loop conformational reorganization are proposed where Arg-289 is critical in determining electrostatic effects of solvent interaction versus Coulombic charging.
Xu, Hua-Neng; Liu, Yang; Zhang, Lianfu
2015-08-07
Emulsions stabilized by protein particles have gained increasing research attention due to their combined advantages of biocompatibility and superior stability. In this study, colloidal particles consisting of soy protein isolates (SPIs) prepared through a heat-treatment procedure are used to make oil-in-water emulsions at a protein concentration of 10 g L(-1) and a pH of 5.91. We investigate parallelly the effects of NaCl on the stability and rheological properties of the particle suspensions and their stabilized emulsions at salt concentrations of 0, 100 and 400 mM. The aggregation behavior of the particles is strongly dependent on the NaCl concentration, showing signs of sedimentation at low NaCl concentration (100 mM) but redispersion again at high NaCl concentration (400 mM). The extensive particle aggregation is beneficial to the formation of a continuous interfacial film for the emulsions, and hence results in a remarkable increase of creaming stability and interfacial viscoelastic moduli. The results can be explained in terms of two competitive effects of NaCl: salting-out and salting-in, which are attributed to complex electrostatic interactions between the particles as a function of NaCl concentration. The delicate balance between salting-out and salting-in provides an interesting insight into the nature of underlying protein particle interactions in aqueous suspensions and a possible mechanism for tailoring their emulsifying properties via salt effects.
Polynomial reduction and evaluation of tree- and loop-level CHY amplitudes
Zlotnikov, Michael
2016-08-24
We develop a polynomial reduction procedure that transforms any gauge fixed CHY amplitude integrand for n scattering particles into a σ-moduli multivariate polynomial of what we call the standard form. We show that a standard form polynomial must have a specific ladder type monomial structure, which has finite size at any n, with highest multivariate degree given by (n – 3)(n – 4)/2. This set of monomials spans a complete basis for polynomials with rational coefficients in kinematic data on the support of scattering equations. Subsequently, at tree and one-loop level, we employ the global residue theorem to derive amore » prescription that evaluates any CHY amplitude by means of collecting simple residues at infinity only. Furthermore, the prescription is then applied explicitly to some tree and one-loop amplitude examples.« less
Multilevel D-loop PCR identification of hunting game.
Parkanyi, V; Ondruska, L; Vasicek, D; Slamecka, J
2014-03-01
The control region of mtDNA (D-loop) was used for hair samples of the five hunting game species identification: red deer (Cervus elaphus), roe deer (Capreolus capreolus), fallow deer (Dama dama), mouflon (Ovis aries musimon), and wild boar (Sus scrofa). For D-loop multilevel PCR detection scheme was applied in six primers (CE CVZV 1 = 5'-GATCACGAGCTTGATCACCA-3'; CE CVZV 2 = 5'-AGGAGTGGGCGATTTTAGGT-3'; DD CVZV 3 = 5'-CGCGTGAAACCAACAACCCGC-3'; DD CVZV 4 = 5'-CCGGGTCGGGGCCTTAGACG-3'; SSW CVZV 5 = 5'-ACACGTGCGTACACGCGCATA-3'; SSW CVZV 6 = 5'-GGTGCCTGCT T TCGTAGCACG-3') designed to identify unknown biological samples of the hunting game animals. The PCR reaction volume was 25 μl at conditions 95 °C for 2 min, 94 °C for 30 s, 60 °C for 30 s, 72 °C for 30 s, 35 cycles, with last extension at 72 °C for 10 min. D-loop mtDNA amplicons of the game animals are characterized with specific PCR product sizes depending on species: red deer = 163 bp and 140 bp, fallow deer = 280 bp and 138 bp, roe deer = 303 bp, 280 bp, 160 bp and 138 bp, mouflon = 299 bp and 178 bp, wild boar = 137 bp and 229 bp.
Travers, Marie-Agnès; Sow, Cissé; Zirah, Séverine; Deregnaucourt, Christiane; Chaouch, Soraya; Queiroz, Rayner M L; Charneau, Sébastien; Allain, Thibault; Florent, Isabelle; Grellier, Philippe
2016-01-01
Giardiasis, currently considered a neglected disease, is caused by the intestinal protozoan parasite Giardia duodenalis and is widely spread in human as well as domestic and wild animals. The lack of appropriate medications and the spread of resistant parasite strains urgently call for the development of novel therapeutic strategies. Host microbiota or certain probiotic strains have the capacity to provide some protection against giardiasis. By combining biological and biochemical approaches, we have been able to decipher a molecular mechanism used by the probiotic strain Lactobacillus johnsonii La1 to prevent Giardia growth in vitro . We provide evidence that the supernatant of this strain contains active principle(s) not directly toxic to Giardia but able to convert non-toxic components of bile into components highly toxic to Giardia . By using bile acid profiling, these components were identified as deconjugated bile-salts. A bacterial bile-salt-hydrolase of commercial origin was able to mimic the properties of the supernatant. Mass spectrometric analysis of the bacterial supernatant identified two of the three bile-salt-hydrolases encoded in the genome of this probiotic strain. These observations document a possible mechanism by which L. johnsonii La1, by secreting, or releasing BSH-like activity(ies) in the vicinity of replicating Giardia in an environment where bile is present and abundant, can fight this parasite. This discovery has both fundamental and applied outcomes to fight giardiasis, based on local delivery of deconjugated bile salts, enzyme deconjugation of bile components, or natural or recombinant probiotic strains that secrete or release such deconjugating activities in a compartment where both bile salts and Giardia are present.
Travers, Marie-Agnès; Sow, Cissé; Zirah, Séverine; Deregnaucourt, Christiane; Chaouch, Soraya; Queiroz, Rayner M. L.; Charneau, Sébastien; Allain, Thibault; Florent, Isabelle; Grellier, Philippe
2016-01-01
Giardiasis, currently considered a neglected disease, is caused by the intestinal protozoan parasite Giardia duodenalis and is widely spread in human as well as domestic and wild animals. The lack of appropriate medications and the spread of resistant parasite strains urgently call for the development of novel therapeutic strategies. Host microbiota or certain probiotic strains have the capacity to provide some protection against giardiasis. By combining biological and biochemical approaches, we have been able to decipher a molecular mechanism used by the probiotic strain Lactobacillus johnsonii La1 to prevent Giardia growth in vitro. We provide evidence that the supernatant of this strain contains active principle(s) not directly toxic to Giardia but able to convert non-toxic components of bile into components highly toxic to Giardia. By using bile acid profiling, these components were identified as deconjugated bile-salts. A bacterial bile-salt-hydrolase of commercial origin was able to mimic the properties of the supernatant. Mass spectrometric analysis of the bacterial supernatant identified two of the three bile-salt-hydrolases encoded in the genome of this probiotic strain. These observations document a possible mechanism by which L. johnsonii La1, by secreting, or releasing BSH-like activity(ies) in the vicinity of replicating Giardia in an environment where bile is present and abundant, can fight this parasite. This discovery has both fundamental and applied outcomes to fight giardiasis, based on local delivery of deconjugated bile salts, enzyme deconjugation of bile components, or natural or recombinant probiotic strains that secrete or release such deconjugating activities in a compartment where both bile salts and Giardia are present. PMID:27729900
Acquisition and Tracking Behavior of Phase-Locked Loops
NASA Technical Reports Server (NTRS)
Viterbi, A. J.
1958-01-01
Phase-locked or APC loops have found increasing applications in recent years as tracking filters, synchronizing devices, and narrowband FM discriminators. Considerable work has been performed to determine the noise-squelching properties of the loop when it is operating in or near phase lock and is functioning as a linear coherent detector. However, insufficient consideration has been devoted to the non-linear behavior of the loop when it is out of lock and in the process of pulling in. Experimental evidence has indicated that there is a strong tendency for phase-locked loops to achieve lock under most circumstances. However, the analysis which has appeared in the literature iis limited to the acquisition of a constant frequency reference signal with only one phase-locked loop filter configuration. This work represents an investigation of frequency acquisition properties of phase-locked loops for a variety of reference-signal behavior and loop configurations
A totally diverting loop colostomy.
Merrett, N. D.; Gartell, P. C.
1993-01-01
A technique is described where the distal limb of a loop colostomy is tied with nylon or polydioxanone. This ensures total faecal diversion and dispenses with the supporting rod, enabling early application of stoma appliances. The technique does not interfere with the traditional transverse closure of a loop colostomy. PMID:8379632
DOE Office of Scientific and Technical Information (OSTI.GOV)
Alam, A.H.M.S.; Pilger, R.H. Jr.
1988-09-01
Subsurface structures were interpreted from seismic images and well logs in the westernmost Mississippi Salt basin, Madison Parish, Louisiana. Structural and stratigraphic relations indicate that salt structures (Duckport, North Tallulah, South Coleman, Tallulah, and Walnut domes) have evolved through pillow, diapir, and postdiapir stages. Withdrawal synclines associated with each stage of growth occur adjacent to salt domes and are characterized by overthickening of sediments. Synclines associated with Walnut dome are particularly well recognized in the seismic data. Primary withdrawal synclines and present day turtle structure anticlines involve the deepest recorded reflections (possibly Jurassic carbonates) above seismically transparent Paleozoic basement andmore » overlying remnant salt. Similar early (Late Jurassic) salt mobility has recently been documented in North Louisiana and East Texas Salt basins. Secondary withdrawal synclines (Cotton Valley) are exceptionally overthickened and their axes are closer to the dome than the axes of primary synclines. Tertiary synclines are broad and appear to be active at present. North-south seismic sections that cross the approximate northwest boundary of the Mississippi Salt basin display post-middle Cretaceous upwarp (the Monroe Uplift) involving basement. Successively older Lower Cretaceous reflections are truncated to the north beneath an erosional surface. Upwarp apparently continued well into the Cenozoic.« less
Wilson loops in supersymmetric gauge theories
NASA Astrophysics Data System (ADS)
Pestun, Vasily
This thesis is devoted to several exact computations in four-dimensional supersymmetric gauge field theories. In the first part of the thesis we prove conjecture due to Erickson-Semenoff-Zarembo and Drukker-Gross which relates supersymmetric circular Wilson loop operators in the N = 4 supersymmetric Yang-Mills theory with a Gaussian matrix model. We also compute the partition function and give a new matrix model formula for the expectation value of a supersymmetric circular Wilson loop operator for the pure N = 2 and the N* = 2 supersymmetric Yang-Mills theory on a four-sphere. Circular supersymmetric Wilson loops in four-dimensional N = 2 superconformal gauge theory are treated similarly. In the second part we consider supersymmetric Wilson loops of arbitrary shape restricted to a two-dimensional sphere in the four-dimensional N = 4 supersymmetric Yang-Mills theory. We show that expectation value for these Wilson loops can be exactly computed using a two-dimensional theory closely related to the topological two-dimensional Higgs-Yang-Mills theory, or two-dimensional Yang-Mills theory for the complexified gauge group.
Synthesis and properties of acetamidinium salts
2011-01-01
Background Acetamidines are starting materials for synthesizing many chemical substances, such as imidazoles, pyrimidines and triazines, which are further used for biochemically active compounds as well as energetic materials. The aim of this study was to synthesise and characterise a range of acetamidinium salts in order to overcome the inconvenience connected with acetamidinium chloride, which is the only commercially available acetamidinium salt. Results Acetamidinium salts were synthesised and characterised by elemental analysis, mass spectrometry, NMR and - in the case of energetic salts - DTA. The structures of previously unknown acetamidinium salts were established by X-ray diffraction analysis. Hygroscopicities in 90% humidity of eight acetamidinium salts were evaluated. Conclusions The different values of hygroscopicity are corroborated by the structures determined by X-ray analysis. The acetamidinium salts with 2D layered structures (acetamidinium nitrate, formate, oxalate and dinitromethanide) show a lack of hygroscopicity, and the compounds with 3D type of structure (acetamidinium chloride, acetate, sulphate and perchlorate) and possessing rather large cavities are quite hygroscopic. PMID:22152129
Mitotic chromosome compaction via active loop extrusion
NASA Astrophysics Data System (ADS)
Goloborodko, Anton; Imakaev, Maxim; Marko, John; Mirny, Leonid; MIT-Northwestern Team
During cell division, two copies of each chromosome are segregated from each other and compacted more than hundred-fold into the canonical X-shaped structures. According to earlier microscopic observations and the recent Hi-C study, chromosomes are compacted into arrays of consecutive loops of ~100 kilobases. Mechanisms that lead to formation of such loop arrays are largely unknown. Here we propose that, during cell division, chromosomes can be compacted by enzymes that extrude loops on chromatin fibers. First, we use computer simulations and analytical modeling to show that a system of loop-extruding enzymes on a chromatin fiber self-organizes into an array of consecutive dynamic loops. Second, we model the process of loop extrusion in 3D and show that, coupled with the topo II strand-passing activity, it leads to robust compaction and segregation of sister chromatids. This mechanism of chromosomal condensation and segregation does not require additional proteins or specific DNA markup and is robust against variations in the number and properties of such loop extruding enzymes. Work at NU was supported by the NSF through Grants DMR-1206868 and MCB-1022117, and by the NIH through Grants GM105847 and CA193419. Work at MIT was supported by the NIH through Grants GM114190 R01HG003143.
Bojowald, Martin
2008-01-01
Quantum gravity is expected to be necessary in order to understand situations in which classical general relativity breaks down. In particular in cosmology one has to deal with initial singularities, i.e., the fact that the backward evolution of a classical spacetime inevitably comes to an end after a finite amount of proper time. This presents a breakdown of the classical picture and requires an extended theory for a meaningful description. Since small length scales and high curvatures are involved, quantum effects must play a role. Not only the singularity itself but also the surrounding spacetime is then modified. One particular theory is loop quantum cosmology, an application of loop quantum gravity to homogeneous systems, which removes classical singularities. Its implications can be studied at different levels. The main effects are introduced into effective classical equations, which allow one to avoid the interpretational problems of quantum theory. They give rise to new kinds of early-universe phenomenology with applications to inflation and cyclic models. To resolve classical singularities and to understand the structure of geometry around them, the quantum description is necessary. Classical evolution is then replaced by a difference equation for a wave function, which allows an extension of quantum spacetime beyond classical singularities. One main question is how these homogeneous scenarios are related to full loop quantum gravity, which can be dealt with at the level of distributional symmetric states. Finally, the new structure of spacetime arising in loop quantum gravity and its application to cosmology sheds light on more general issues, such as the nature of time. Supplementary material is available for this article at 10.12942/lrr-2008-4.
Methods to Prepare Aluminum Salt-Adjuvanted Vaccines.
Thakkar, Sachin G; Cui, Zhengrong
2017-01-01
Many human vaccines contain certain insoluble aluminum salts such as aluminum oxyhydroxide and aluminum hydroxyphosphate as vaccine adjuvants to boost the immunogenicity of the vaccines. Aluminum salts have been used as vaccine adjuvants for decades and have an established, favorable safety profile. However, preparing aluminum salts and aluminum salt-adjuvanted vaccines in a consistent manner remains challenging. This chapter discusses methods to prepare aluminum salts and aluminum salt-adjuvanted vaccines, factors to consider during preparation, and methods to characterize the vaccines after preparation.
Process evaluation of sea salt aerosol concentrations at remote marine locations
NASA Astrophysics Data System (ADS)
Struthers, H.; Ekman, A. M.; Nilsson, E. D.
2011-12-01
are analysed to quantify the key sensitivities of the processes connecting the physical drivers of sea salt aerosol to the mass tendency. The analysis employs a semi-empirical model based on the time-tendency of the aerosol mass. This approach of focusing on the time-tendency of the sea salt aerosol concentration provides a framework for the process evaluation of sea salt aerosol concentrations in global models. The same analysis methodology can be applied to output from global models. A process of comparing the sensitivity parameters derived from observations and models will reveal model inadequacies and thus guide model improvements. Carslaw, K. S., Boucher, O., Spracklen, D. V., Mann G. W., Rae, J. G. L, Woodward, S., Kulmala, M. (2010). Atmos. Chem. Phys., 10, 1701-1737 IPCC (2007). Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, Solomon, S., D. Monahan, E. C., Spiel, D. E., Davidson, K. L. (1986) Oceanic Whitecaps ed. Monahan E. C. & MacNiochaill, D. Reidel, Norwell, Mass. Texor, C., et al. (2006) Atmos. Chem. Phys., 6, 1777-1813.
Salt intake and dietary sources of salt on weekdays and weekend days in Australian adults.
Nowson, Caryl; Lim, Karen; Land, Mary-Ann; Webster, Jacqui; Shaw, Jonathan E; Chalmers, John; Flood, Victoria; Woodward, Mark; Grimes, Carley
2018-02-01
To assess if there is a difference in salt intake (24 h urine collection and dietary recall) and dietary sources of salt (Na) on weekdays and weekend days. A cross-sectional study of adults who provided one 24 h urine collection and one telephone-administered 24 h dietary recall. Community-dwelling adults living in the State of Victoria, Australia. Adults (n 598) who participated in a health survey (53·5 % women; mean age 57·1 (95 % CI 56·2, 58·1) years). Mean (95 % CI) salt intake (dietary recall) was 6·8 (6·6, 7·1) g/d and 24 h urinary salt excretion was 8·1 (7·8, 8·3) g/d. Mean dietary and 24 h urinary salt (age-adjusted) were 0·9 (0·1, 1·6) g/d (P=0·024) and 0·8 (0·3, 1·6) g/d (P=0·0017), respectively, higher at weekends compared with weekdays. There was an indication of a greater energy intake at weekends (+0·6 (0·02, 1·2) MJ/d, P=0·06), but no difference in Na density (weekday: 291 (279, 304) mg/MJ; weekend: 304 (281, 327) mg/MJ; P=0·360). Cereals/cereal products and dishes, meat, poultry, milk products and gravy/sauces accounted for 71 % of dietary Na. Mean salt intake (24 h urine collection) was more than 60 % above the recommended level of 5 g salt/d and 8-14 % more salt was consumed at weekends than on weekdays. Substantial reductions in the Na content of staple foods, processed meat, sauces, mixed dishes (e.g. pasta), convenience and takeaway foods are required to achieve a significant consistent reduction in population salt intake throughout the week.
The performance of a sampled data delay lock loop implemented with a Kalman loop filter
NASA Astrophysics Data System (ADS)
Eilts, H. S.
1980-01-01
The purpose of this study is to evaluate the steady-state and transient (lock-up) performance of a tracking loop implemented with a Kalman filter. Steady-state performance criteria are errors due to measurement noise (jitter) and Doppler errors due to motion of the tracking loop. Trade-offs exist between the two criteria such that increasing performance with respect to either one will cause performance decrease with respect to the other. It is shown that by carefully selecting filter parameters reasonable performance can be obtained for both criteria simultaneously. It is also shown that lock-up performance for the loop is acceptable when these parameters are used.
The Width Distribution of Loops and Strands in the Solar Corona—Are We Hitting Rock Bottom?
NASA Astrophysics Data System (ADS)
Aschwanden, Markus J.; Peter, Hardi
2017-05-01
In this study, we analyze Atmospheric Imaging Assembly (AIA) and Hi-C images in order to investigate absolute limits for the finest loop strands. We develop a model of the occurrence-size distribution function of coronal loop widths, characterized by the lower limit of widths w min, the peak (or most frequent) width w p , the peak occurrence number n p , and a power-law slope a. Our data analysis includes automated tracing of curvilinear features with the OCCULT-2 code, automated sampling of the cross-sectional widths of coronal loops, and fitting of the theoretical size distribution to the observed distribution. With Monte Carlo simulations and variable pixel sizes {{Δ }}x, we derive a first diagnostic criterion to discriminate whether the loop widths are unresolved ({w}p/{{Δ }}x≈ 2.5+/- 0.2) or fully resolved (if {w}p/{{Δ }}x≳ 2.7). For images with resolved loop widths, we can apply a second diagnostic criterion that predicts the lower limit of loop widths as a function of the spatial resolution. We find that the loop widths are marginally resolved in AIA images but are fully resolved in Hi-C images, where our model predicts a most frequent (peak) value at {w}p≈ 550 {km}, in agreement with recent results of Brooks et al. This result agrees with the statistics of photospheric granulation sizes and thus supports coronal heating mechanisms operating on the macroscopic scale of photospheric magneto-convection, rather than nanoflare braiding models on unresolved microscopic scales.
Osmotic mechanism of the loop extrusion process
NASA Astrophysics Data System (ADS)
Yamamoto, Tetsuya; Schiessel, Helmut
2017-09-01
The loop extrusion theory assumes that protein factors, such as cohesin rings, act as molecular motors that extrude chromatin loops. However, recent single molecule experiments have shown that cohesin does not show motor activity. To predict the physical mechanism involved in loop extrusion, we here theoretically analyze the dynamics of cohesin rings on a loop, where a cohesin loader is in the middle and unloaders at the ends. Cohesin monomers bind to the loader rather frequently and cohesin dimers bind to this site only occasionally. Our theory predicts that a cohesin dimer extrudes loops by the osmotic pressure of cohesin monomers on the chromatin fiber between the two connected rings. With this mechanism, the frequency of the interactions between chromatin segments depends on the loading and unloading rates of dimers at the corresponding sites.
Wilson loops in warped resolved deformed conifolds
DOE Office of Scientific and Technical Information (OSTI.GOV)
Bennett, Stephen, E-mail: pystephen@swansea.ac.uk
We calculate quark-antiquark potentials using the relationship between the expectation value of the Wilson loop and the action of a probe string in the string dual. We review and categorise the possible forms of the dependence of the energy on the separation between the quarks. In particular, we examine the possibility of there being a minimum separation for probe strings which do not penetrate close to the origin of the bulk space, and derive a condition which determines whether this is the case. We then apply these considerations to the flavoured resolved deformed conifold background of Gaillard et al. (2010)more » . We suggest that the unusual behaviour that we observe in this solution is likely to be related to the IR singularity which is not present in the unflavoured case. - Highlights: > We calculate quark-antiquark potentials using the Wilson loop and the action of a probe string in the string dual. > We review and categorise the possible forms of the dependence of the energy on the separation between the quarks. > We look in particular at the flavoured resolved deformed conifold. > There appears to be unusual behaviour which seems likely to be related to the IR singularity introduced by flavours.« less
Novel Numerical Approaches to Loop Quantum Cosmology
NASA Astrophysics Data System (ADS)
Diener, Peter
2015-04-01
Loop Quantum Gravity (LQG) is an (as yet incomplete) approach to the quantization of gravity. When applied to symmetry reduced cosmological spacetimes (Loop Quantum Cosmology or LQC) one of the predictions of the theory is that the Big Bang is replaced by a Big Bounce, i.e. a previously existing contracting universe underwent a bounce at finite volume before becoming our expanding universe. The evolution equations of LQC take the form of difference equations (with the discretization given by the theory) that in the large volume limit can be approximated by partial differential equations (PDEs). In this talk I will first discuss some of the unique challenges encountered when trying to numerically solve these difference equations. I will then present some of the novel approaches that have been employed to overcome the challenges. I will here focus primarily on the Chimera scheme that takes advantage of the fact that the LQC difference equations can be approximated by PDEs in the large volume limit. I will finally also briefly discuss some of the results that have been obtained using these numerical techniques by performing simulations in regions of parameter space that were previously unreachable. This work is supported by a grant from the John Templeton Foundation and by NSF grant PHYS1068743.
Measuring salt retention : [summary].
DOT National Transportation Integrated Search
2013-03-01
This project involves measuring and reporting the retention of salt and brine on the roadway as a result of using different salt spreaders, application speeds, and brine quantities. The research develops an evaluation methodology, directs the field c...
Stephens, Doyle W.; Gardner, Joe F.
1999-01-01
This document is intended as a source of general information and facts about Great Salt Lake, Utah. This U.S. Geological Survey information sheet answers frequently asked questions about Great Salt Lake. Topics include: History, salinity, brine shrimp, brine flies, migratory birds, and recreation. Great Salt Lake, the shrunken remnant of prehistoric Lake Bonneville, has no outlet. Dissolved salts accumulate in the lake by evaporation. Salinity south of the causeway has ranged from 6 percent to 27 percent over a period of 22 years (2 to 7 times saltier than the ocean). The high salinity supports a mineral industry that extracts about 2 million tons of salt from the lake each year. The aquatic ecosystem consists of more than 30 species of organisms. Harvest of its best-known species, the brine shrimp, annually supplies millions of pounds of food for the aquaculture industry worldwide. The lake is used extensively by millions of migratory and nesting birds and is a place of solitude for people. All this occurs in a lake that is located at the bottom of a 35,000-square-mile drainage basin that has a human population of more than 1.5 million.
Sripinyowanich, Siriporn; Chamnanmanoontham, Nontalee; Udomchalothorn, Thanikarn; Maneeprasopsuk, Somporn; Santawee, Panudda; Buaboocha, Teerapong; Qu, Li-Jia; Gu, Hongya; Chadchawan, Supachitra
2013-12-01
The rice (Oryza sativa L.) nucleolin gene, OsNUC1, transcripts were expressed in rice leaves, flowers, seeds and roots but differentially expressed within and between two pairs of salt-sensitive and salt-resistant rice lines when subjected to salt stress. Salt-resistant lines exhibited higher OsNUC1 transcript expression levels than salt-sensitive lines during 0.5% (w/v) NaCl salt stress for 6d. Two sizes of OsNUC1 full-length cDNA were found in the rice genome database and northern blot analysis confirmed their existence in rice tissues. The longer transcript (OsNUC1-L) putatively encodes for a protein with a serine rich N-terminal, RNA recognition motifs in the central domain and a glycine- and arginine-rich repeat in the C-terminal domain, while the shorter one (OsNUC1-S) putatively encodes for the similar protein without the N-terminus. Without salt stress, OsNUC1-L expressing Arabidopsis thaliana Atnuc1-L1 plants displayed a substantial but incomplete revertant phenotype, whereas OsNUC1-S expression only induced a weak effect. However, under 0.5% (w/v) NaCl salt stress they displayed a higher relative growth rate, longer root length and a lower H2O2 level than the wild type plants, suggesting a higher salt resistance. Moreover, they displayed elevated AtSOS1 and AtP5CS1 transcript levels. We propose that OsNUC1-S plays an important role in salt resistance during salt stress, a new role for nucleolin in plants. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.
NASA Astrophysics Data System (ADS)
da Silva, Cameron Capeletti; Guimarães, Freddy Fernandes; Ribeiro, Leandro; Martins, Felipe Terra
2016-10-01
The recognition of the nature of a multicomponent crystal form (solvate, salt, cocrystal or cocrystal of salt) is of great importance for pharmaceutical industry because it is directly related to the performance of a pharmaceutical ingredient, since there is interdependence between the structure, its energy and its physical properties. In this context, here we have identified the nature of multicomponent crystal forms of the anti-HIV drug lamivudine with mandelic acid through infrared spectroscopy. These investigated crystal forms were the known S-mandelic acid cocrystal of lamivudine R-mandelate trihydrate (1), a cocrystal of salt, and lamivudine R-mandelate (2), a salt. This approach also supports the identification and distinction of both ionized and unionized forms of mandelic acid in the infrared spectrum of 1. In this way, infrared spectroscopy can be useful to distinguish a cocrystal of salt from either salt or cocrystal forms. In the course of this study, for the first time we have also characterized and determined the crystal structure of R-mandelic acid cocrystal of sodium R-mandelate (3).
EFFECTS OF CHRONIC EXCESS SALT FEEDING
Dahl, Lewis K.; Heine, Martha
1961-01-01
Female rats were fed diets containing either excess sea salt or excess sodium chloride for periods up to 14 months. The hypertension produced by sea salt was more pronounced than that caused by sodium chloride alone, although the average amount of sodium chloride contained in the sea salt feeding was slightly less. The ions involved in this incremental effect of sea salt were not identified. PMID:13719314
Salt-Bridge Energetics in Halophilic Proteins
Nayek, Arnab; Sen Gupta, Parth Sarthi; Banerjee, Shyamashree; Mondal, Buddhadev; Bandyopadhyay, Amal K.
2014-01-01
Halophilic proteins have greater abundance of acidic over basic and very low bulky hydrophobic residues. Classical electrostatic stabilization was suggested as the key determinant for halophilic adaptation of protein. However, contribution of specific electrostatic interactions (i.e. salt-bridges) to overall stability of halophilic proteins is yet to be understood. To understand this, we use Adaptive-Poison-Boltzmann-Solver Methods along with our home-built automation to workout net as well as associated component energy terms such as desolvation energy, bridge energy and background energy for 275 salt-bridges from 20 extremely halophilic proteins. We then perform extensive statistical analysis on general and energetic attributes on these salt-bridges. On average, 8 salt-bridges per 150 residues protein were observed which is almost twice than earlier report. Overall contributions of salt-bridges are −3.0 kcal mol−1. Majority (78%) of salt-bridges in our dataset are stable and conserved in nature. Although, average contributions of component energy terms are equal, their individual details vary greatly from one another indicating their sensitivity to local micro-environment. Notably, 35% of salt-bridges in our database are buried and stable. Greater desolvation penalty of these buried salt-bridges are counteracted by stable network salt-bridges apart from favorable equal contributions of bridge and background terms. Recruitment of extensive network salt-bridges (46%) with a net contribution of −5.0 kcal mol−1 per salt-bridge, seems to be a halophilic design wherein favorable average contribution of background term (−10 kcal mol−1) exceeds than that of bridge term (−7 kcal mol−1). Interiors of proteins from halophiles are seen to possess relatively higher abundance of charge and polar side chains than that of mesophiles which seems to be satisfied by cooperative network salt-bridges. Overall, our theoretical analyses provide insight into halophilic
Salt-bridge energetics in halophilic proteins.
Nayek, Arnab; Sen Gupta, Parth Sarthi; Banerjee, Shyamashree; Mondal, Buddhadev; Bandyopadhyay, Amal K
2014-01-01
Halophilic proteins have greater abundance of acidic over basic and very low bulky hydrophobic residues. Classical electrostatic stabilization was suggested as the key determinant for halophilic adaptation of protein. However, contribution of specific electrostatic interactions (i.e. salt-bridges) to overall stability of halophilic proteins is yet to be understood. To understand this, we use Adaptive-Poison-Boltzmann-Solver Methods along with our home-built automation to workout net as well as associated component energy terms such as desolvation energy, bridge energy and background energy for 275 salt-bridges from 20 extremely halophilic proteins. We then perform extensive statistical analysis on general and energetic attributes on these salt-bridges. On average, 8 salt-bridges per 150 residues protein were observed which is almost twice than earlier report. Overall contributions of salt-bridges are -3.0 kcal mol-1. Majority (78%) of salt-bridges in our dataset are stable and conserved in nature. Although, average contributions of component energy terms are equal, their individual details vary greatly from one another indicating their sensitivity to local micro-environment. Notably, 35% of salt-bridges in our database are buried and stable. Greater desolvation penalty of these buried salt-bridges are counteracted by stable network salt-bridges apart from favorable equal contributions of bridge and background terms. Recruitment of extensive network salt-bridges (46%) with a net contribution of -5.0 kcal mol-1 per salt-bridge, seems to be a halophilic design wherein favorable average contribution of background term (-10 kcal mol-1) exceeds than that of bridge term (-7 kcal mol-1). Interiors of proteins from halophiles are seen to possess relatively higher abundance of charge and polar side chains than that of mesophiles which seems to be satisfied by cooperative network salt-bridges. Overall, our theoretical analyses provide insight into halophilic signature in its
Development of Hardware-in-the-loop Microgrid Testbed
DOE Office of Scientific and Technical Information (OSTI.GOV)
Xiao, Bailu; Prabakar, Kumaraguru; Starke, Michael R
2015-01-01
A hardware-in-the-loop (HIL) microgrid testbed for the evaluation and assessment of microgrid operation and control system has been presented in this paper. The HIL testbed is composed of a real-time digital simulator (RTDS) for modeling of the microgrid, multiple NI CompactRIOs for device level control, a prototype microgrid energy management system (MicroEMS), and a relay protection system. The applied communication-assisted hybrid control system has been also discussed. Results of function testing of HIL controller, communication, and the relay protection system are presented to show the effectiveness of the proposed HIL microgrid testbed.
Velocity Measurements for a Solar Active Region Fan Loop from Hinode/EIS Observations
NASA Astrophysics Data System (ADS)
Young, P. R.; O'Dwyer, B.; Mason, H. E.
2012-01-01
The velocity pattern of a fan loop structure within a solar active region over the temperature range 0.15-1.5 MK is derived using data from the EUV Imaging Spectrometer (EIS) on board the Hinode satellite. The loop is aligned toward the observer's line of sight and shows downflows (redshifts) of around 15 km s-1 up to a temperature of 0.8 MK, but for temperatures of 1.0 MK and above the measured velocity shifts are consistent with no net flow. This velocity result applies over a projected spatial distance of 9 Mm and demonstrates that the cooler, redshifted plasma is physically disconnected from the hotter, stationary plasma. A scenario in which the fan loops consist of at least two groups of "strands"—one cooler and downflowing, the other hotter and stationary—is suggested. The cooler strands may represent a later evolutionary stage of the hotter strands. A density diagnostic of Mg VII was used to show that the electron density at around 0.8 MK falls from 3.2 × 109 cm-3 at the loop base, to 5.0 × 108 cm-3 at a projected height of 15 Mm. A filling factor of 0.2 is found at temperatures close to the formation temperature of Mg VII (0.8 MK), confirming that the cooler, downflowing plasma occupies only a fraction of the apparent loop volume. The fan loop is rooted within a so-called outflow region that displays low intensity and blueshifts of up to 25 km s-1 in Fe XII λ195.12 (formed at 1.5 MK), in contrast to the loop's redshifts of 15 km s-1 at 0.8 MK. A new technique for obtaining an absolute wavelength calibration for the EIS instrument is presented and an instrumental effect, possibly related to a distorted point-spread function, that affects velocity measurements is identified.
VELOCITY MEASUREMENTS FOR A SOLAR ACTIVE REGION FAN LOOP FROM HINODE/EIS OBSERVATIONS
DOE Office of Scientific and Technical Information (OSTI.GOV)
Young, P. R.; O'Dwyer, B.; Mason, H. E.
2012-01-01
The velocity pattern of a fan loop structure within a solar active region over the temperature range 0.15-1.5 MK is derived using data from the EUV Imaging Spectrometer (EIS) on board the Hinode satellite. The loop is aligned toward the observer's line of sight and shows downflows (redshifts) of around 15 km s{sup -1} up to a temperature of 0.8 MK, but for temperatures of 1.0 MK and above the measured velocity shifts are consistent with no net flow. This velocity result applies over a projected spatial distance of 9 Mm and demonstrates that the cooler, redshifted plasma is physicallymore » disconnected from the hotter, stationary plasma. A scenario in which the fan loops consist of at least two groups of 'strands'-one cooler and downflowing, the other hotter and stationary-is suggested. The cooler strands may represent a later evolutionary stage of the hotter strands. A density diagnostic of Mg VII was used to show that the electron density at around 0.8 MK falls from 3.2 Multiplication-Sign 10{sup 9} cm{sup -3} at the loop base, to 5.0 Multiplication-Sign 10{sup 8} cm{sup -3} at a projected height of 15 Mm. A filling factor of 0.2 is found at temperatures close to the formation temperature of Mg VII (0.8 MK), confirming that the cooler, downflowing plasma occupies only a fraction of the apparent loop volume. The fan loop is rooted within a so-called outflow region that displays low intensity and blueshifts of up to 25 km s{sup -1} in Fe XII {lambda}195.12 (formed at 1.5 MK), in contrast to the loop's redshifts of 15 km s{sup -1} at 0.8 MK. A new technique for obtaining an absolute wavelength calibration for the EIS instrument is presented and an instrumental effect, possibly related to a distorted point-spread function, that affects velocity measurements is identified.« less
Pore-scale dynamics of salt transport and distribution in drying porous media
NASA Astrophysics Data System (ADS)
Shokri, Nima
2014-01-01
Understanding the physics of water evaporation from saline porous media is important in many natural and engineering applications such as durability of building materials and preservation of monuments, water quality, and mineral-fluid interactions. We applied synchrotron x-ray micro-tomography to investigate the pore-scale dynamics of dissolved salt distribution in a three dimensional drying saline porous media using a cylindrical plastic column (15 mm in height and 8 mm in diameter) packed with sand particles saturated with CaI2 solution (5% concentration by mass) with a spatial and temporal resolution of 12 μm and 30 min, respectively. Every time the drying sand column was set to be imaged, two different images were recorded using distinct synchrotron x-rays energies immediately above and below the K-edge value of Iodine. Taking the difference between pixel gray values enabled us to delineate the spatial and temporal distribution of CaI2 concentration at pore scale. Results indicate that during early stages of evaporation, air preferentially invades large pores at the surface while finer pores remain saturated and connected to the wet zone at bottom via capillary-induced liquid flow acting as evaporating spots. Consequently, the salt concentration increases preferentially in finer pores where evaporation occurs. Higher salt concentration was observed close to the evaporating surface indicating a convection-driven process. The obtained salt profiles were used to evaluate the numerical solution of the convection-diffusion equation (CDE). Results show that the macro-scale CDE could capture the overall trend of the measured salt profiles but fail to produce the exact slope of the profiles. Our results shed new insight on the physics of salt transport and its complex dynamics in drying porous media and establish synchrotron x-ray tomography as an effective tool to investigate the dynamics of salt transport in porous media at high spatial and temporal resolution.
Direct-contact closed-loop heat exchanger
Berry, Gregory F.; Minkov, Vladimir; Petrick, Michael
1984-01-01
A high temperature heat exchanger with a closed loop and a heat transfer liquid within the loop, the closed loop having a first horizontal channel with inlet and outlet means for providing direct contact of a first fluid at a first temperature with the heat transfer liquid, a second horizontal channel with inlet and outlet means for providing direct contact of a second fluid at a second temperature with the heat transfer liquid, and means for circulating the heat transfer liquid.
saltPAD: A New Analytical Tool for Monitoring Salt Iodization in Low Resource Settings
Myers, Nicholas M.; Strydom, Emmerentia Elza; Sweet, James; Sweet, Christopher; Spohrer, Rebecca; Dhansay, Muhammad Ali; Lieberman, Marya
2016-01-01
We created a paper test card that measures a common iodizing agent, iodate, in salt. To test the analytical metrics, usability, and robustness of the paper test card when it is used in low resource settings, the South African Medical Research Council and GroundWork performed independent validation studies of the device. The accuracy and precision metrics from both studies were comparable. In the SAMRC study, more than 90% of the test results (n=1704) were correctly classified as corresponding to adequately or inadequately iodized salt. The cards are suitable for market and household surveys to determine whether salt is adequately iodized. Further development of the cards will improve their utility for monitoring salt iodization during production. PMID:29942380
Molten salt electrolyte separator
Kaun, Thomas D.
1996-01-01
A molten salt electrolyte/separator for battery and related electrochemical systems including a molten electrolyte composition and an electrically insulating solid salt dispersed therein, to provide improved performance at higher current densities and alternate designs through ease of fabrication.
Loop equations and bootstrap methods in the lattice
Anderson, Peter D.; Kruczenski, Martin
2017-06-17
Pure gauge theories can be formulated in terms of Wilson Loops by means of the loop equation. In the large-N limit this equation closes in the expectation value of single loops. In particular, using the lattice as a regulator, it becomes a well defined equation for a discrete set of loops. In this paper we study different numerical approaches to solving this equation.
Electrochromic Salts, Solutions, and Devices
Burrell, Anthony K.; Warner, Benjamin P.; McClesky, T. Mark
2008-11-11
Electrochromic salts. Electrochromic salts of dicationic viologens such as methyl viologen and benzyl viologen associated with anions selected from bis(trifluoromethylsulfonyl)imide, bis(perfluoroethylsulfonyl)imide, and tris(trifluoromethylsulfonyl)methide are produced by metathesis with the corresponding viologen dihalide. They are highly soluble in molten quarternary ammonium salts and together with a suitable reductant provide electrolyte solutions that are used in electrochromic windows.
Electrochromic salts, solutions, and devices
Burrell, Anthony K [Los Alamos, NM; Warner, Benjamin P [Los Alamos, NM; McClesky,7,064,212 T. Mark
2006-06-20
Electrochromic salts. Electrochromic salts of dicationic viologens such as methyl viologen and benzyl viologen associated with anions selected from bis(trifluoromethylsulfonyl)imide, bis(perfluoroethylsulfonyl)imide, and tris(trifluoromethylsulfonyl)methide are produced by metathesis with the corresponding viologen dihalide. They are highly soluble in molten quarternary ammonium salts and together with a suitable reductant provide electrolyte solutions that are used in electrochromic windows.
Electrochromic Salts, Solutions, and Devices
Burrell, Anthony K.; Warner, Benjamin P.; McClesky, T. Mark
2008-10-14
Electrochromic salts. Electrochromic salts of dicationic viologens such as methyl viologen and benzyl viologen associated with anions selected from bis(trifluoromethylsulfonyl)imide, bis(perfluoroethylsulfonyl)imide, and tris(trifluoromethylsulfonyl)methide are produced by metathesis with the corresponding viologen dihalide. They are highly soluble in molten quarternary ammonium salts and together with a suitable reductant provide electrolyte solutions that are used in electrochromic windows.
On coincident loop transient electromagnetic induction logging
DOE Office of Scientific and Technical Information (OSTI.GOV)
Swidinsky, Andrei; Weiss, Chester J.
Coincident loop transient induction wireline logging is examined as the borehole analog of the well-known land and airborne time-domain electromagnetic (EM) method. The concept of whole-space late-time apparent resistivity is modified from the half-space version commonly used in land and airborne geophysics and applied to the coincident loop voltages produced from various formation, borehole, and invasion models. Given typical tool diameters, off-time measurements with such an instrument must be made on the order of nanoseconds to microseconds — much more rapidly than for surface methods. Departure curves of the apparent resistivity for thin beds, calculated using an algorithm developed tomore » model the transient response of a loop in a multilayered earth, indicate that the depth of investigation scales with the bed thickness. Modeled resistivity logs are comparable in accuracy and resolution with standard frequency-domain focused induction logs. However, if measurement times are longer than a few microseconds, the thicknesses of conductors can be overestimated, whereas resistors are underestimated. Thin-bed resolution characteristics are explained by visualizing snapshots of the EM fields in the formation, where a conductor traps the electric field while two current maxima are produced in the shoulder beds surrounding a resistor. Radial profiling is studied using a concentric cylinder earth model. Results found that true formation resistivity can be determined in the presence of either oil- or water-based mud, although in the latter case, measurements must be taken several orders of magnitude later in time. Lastly, the ability to determine true formation resistivity is governed by the degree that the EM field heals after being distorted by borehole fluid and invasion, a process visualized and particularly evident in the case of conductive water-based mud.« less
On coincident loop transient electromagnetic induction logging
Swidinsky, Andrei; Weiss, Chester J.
2017-05-31
Coincident loop transient induction wireline logging is examined as the borehole analog of the well-known land and airborne time-domain electromagnetic (EM) method. The concept of whole-space late-time apparent resistivity is modified from the half-space version commonly used in land and airborne geophysics and applied to the coincident loop voltages produced from various formation, borehole, and invasion models. Given typical tool diameters, off-time measurements with such an instrument must be made on the order of nanoseconds to microseconds — much more rapidly than for surface methods. Departure curves of the apparent resistivity for thin beds, calculated using an algorithm developed tomore » model the transient response of a loop in a multilayered earth, indicate that the depth of investigation scales with the bed thickness. Modeled resistivity logs are comparable in accuracy and resolution with standard frequency-domain focused induction logs. However, if measurement times are longer than a few microseconds, the thicknesses of conductors can be overestimated, whereas resistors are underestimated. Thin-bed resolution characteristics are explained by visualizing snapshots of the EM fields in the formation, where a conductor traps the electric field while two current maxima are produced in the shoulder beds surrounding a resistor. Radial profiling is studied using a concentric cylinder earth model. Results found that true formation resistivity can be determined in the presence of either oil- or water-based mud, although in the latter case, measurements must be taken several orders of magnitude later in time. Lastly, the ability to determine true formation resistivity is governed by the degree that the EM field heals after being distorted by borehole fluid and invasion, a process visualized and particularly evident in the case of conductive water-based mud.« less
Computational gene expression profiling under salt stress reveals patterns of co-expression
Sanchita; Sharma, Ashok
2016-01-01
Plants respond differently to environmental conditions. Among various abiotic stresses, salt stress is a condition where excess salt in soil causes inhibition of plant growth. To understand the response of plants to the stress conditions, identification of the responsible genes is required. Clustering is a data mining technique used to group the genes with similar expression. The genes of a cluster show similar expression and function. We applied clustering algorithms on gene expression data of Solanum tuberosum showing differential expression in Capsicum annuum under salt stress. The clusters, which were common in multiple algorithms were taken further for analysis. Principal component analysis (PCA) further validated the findings of other cluster algorithms by visualizing their clusters in three-dimensional space. Functional annotation results revealed that most of the genes were involved in stress related responses. Our findings suggest that these algorithms may be helpful in the prediction of the function of co-expressed genes. PMID:26981411
DOE Office of Scientific and Technical Information (OSTI.GOV)
Perrot, F.
The low background gamma spectroscopy has been applied to try to sign the geographical origin of the French atlantic marine salts and of the prunes from Agen. Most of the activity measurements have been done using low background Ge spectrometers located in Bordeaux. Results have shown that a clear signature exists in the case of the French atlantic salts using the 40K, 137Cs and 226Ra isotopes but not in the case of the prunes.
Discretionary salt use in airline meal service.
Wallace, S; Wellman, N S; Dierkes, K E; Johnson, P M
1987-02-01
Salt use in airline meal service was studied through observation of returned meal trays of 932 passengers. Observation and weighing of salt packets on returned trays revealed that 64% of passengers did not salt their airline dinner, while 6% used the entire salt packet, 0.92 gm NaCl (362 mg Na). Average discretionary salt use among the 234 passengers (25%) who added salt was 0.57 gm NaCl (232 mg Na). Estimates of total sodium in the four airline dinners averaged 2.0 gm NaCl (786 mg Na). Laboratory assays of menu items produced by the airline foodservice differed 3% to 19% from estimated values. Sodium content of the four airline dinner menus was similar and did not affect salt use. Discretionary salt use was related to the total amount of entrée consumed but was not affected by the amount of salad consumed. It is postulated that salt use in the "captive" airline situation is predicated on consistent, habitual practices. Lowering sodium consumption in this setting may require alteration in both food preparation methods and quantity of salt presented in the packets.
Wang, Y; Mu, J J; Liu, F Q; Ren, K Y; Xiao, H Y; Yang, Z; Yuan, Z Y
2014-02-01
Dietary salt intake has been linked to hypertension and cardiovascular disease. Accumulating evidence has indicated that salt-sensitive individuals on high salt intake are more likely to develop renal fibrosis. Epithelial-to-mesenchymal transition (EMT) participates in the development and progression of renal fibrosis in humans and animals. The objective of this study was to investigate the impact of a high-salt diet on EMT in Dahl salt-sensitive (SS) rats. Twenty-four male SS and consomic SS-13(BN) rats were randomized to a normal diet or a high-salt diet. After 4 weeks, systolic blood pressure (SBP) and albuminuria were analyzed, and renal fibrosis was histopathologically evaluated. Tubular EMT was evaluated using immunohistochemistry and real-time PCR with E-cadherin and alpha smooth muscle actin (α-SMA). After 4 weeks, SBP and albuminuria were significantly increased in the SS high-salt group compared with the normal diet group. Dietary salt intake induced renal fibrosis and tubular EMT as identified by reduced expression of E-cadherin and enhanced expression of α-SMA in SS rats. Both blood pressure and renal interstitial fibrosis were negatively correlated with E-cadherin but positively correlated with α-SMA. Salt intake induced tubular EMT and renal injury in SS rats, and this relationship might depend on the increase in blood pressure.
One loop back reaction on power law inflation
DOE Office of Scientific and Technical Information (OSTI.GOV)
Abramo, L.R.; Woodard, R.P.
1999-08-01
We consider quantum-mechanical corrections to a homogeneous, isotropic, and spatially flat geometry whose scale factor expands classically as a general power of the comoving time. The effects of both gravitons and the scalar inflaton are computed at one loop using the manifestly causal formalism of Schwinger [J. Math. Phys. {bold 2}, 407 (1961); {ital Particles, Sources and Fields} (Addison, Wesley, Reading, MA, 1970)] with the Feynman rules recently developed by Iliopoulos {ital et al.} [Nucl. Phys. B {bold 534}, 419 (1998)]. We find no significant effect, in marked contrast to the result obtained by Mukhanov and co-workers [Phys. Rev. Lett.more » {bold 78}, 1624 (1998); Phys. Rev. D {bold 56}, 3248 (1997)] for chaotic inflation based on a quadratic potential. By applying the canonical technique of Mukhanov and co-workers to the exponential potentials of power law inflation, we show that the two methods produce the same results, within the approximations employed, for these backgrounds. We therefore conclude that the shape of the inflaton potential can have an enormous impact on the one loop back reaction. {copyright} {ital 1999} {ital The American Physical Society}« less
Te homogeneous precipitation in Ge dislocation loop vicinity
DOE Office of Scientific and Technical Information (OSTI.GOV)
Perrin Toinin, J.; Portavoce, A., E-mail: alain.portavoce@im2np.fr; Texier, M.
2016-06-06
High resolution microscopies were used to study the interactions of Te atoms with Ge dislocation loops, after a standard n-type doping process in Ge. Te atoms neither segregate nor precipitate on dislocation loops, but form Te-Ge clusters at the same depth as dislocation loops, in contradiction with usual dopant behavior and thermodynamic expectations. Atomistic kinetic Monte Carlo simulations show that Te atoms are repulsed from dislocation loops due to elastic interactions, promoting homogeneous Te-Ge nucleation between dislocation loops. This phenomenon is enhanced by coulombic interactions between activated Te{sup 2+} or Te{sup 1+} ions.
Zhou, Xiaoyan; Forrest, Michael J; Sharif-Rodriguez, Wanda; Forrest, Gail; Szeto, Daphne; Urosevic-Price, Olga; Zhu, Yonghua; Stevenson, Andra S; Zhou, Yuchen; Stribling, Sloan; Dajee, Maya; Walsh, Shawn P; Pasternak, Alexander; Sullivan, Kathleen A
2017-02-01
The renal outer medullary potassium (ROMK) channel mediates potassium recycling and facilitates sodium reabsorption through the Na + /K + /2Cl - cotransporter in the loop of Henle and potassium secretion at the cortical collecting duct. Evidence from the phenotype of humans and rodents with functional ROMK deficiency supports the contention that selective ROMK inhibitors (ROMKi) will represent a novel diuretic with potential of therapeutic benefit for hypertension. ROMKi have recently been synthesized by Merck & Co, Inc. The present studies were designed to examine the effects of ROMKi B on systemic hemodynamics, renal function and structure, and vascular function in Dahl salt-sensitive rats. Four experimental groups-control, high-salt diet alone; ROMKi B 3 mg·kg - 1 ·d - 1 ; ROMKi B 10 mg·kg - 1 ·d - 1 ; and hydrochlorothiazide 25 mg·kg - 1 ·d - 1 -were included in prophylactic (from week 1 to week 9 on high-salt diet) and therapeutic studies (from week 5 to week 9 on high-salt diet), respectively. ROMKi B produced sustained blood pressure reduction and improved renal and vascular function and histological alterations induced by a high-salt diet. ROMKi B was superior to hydrochlorothiazide at reducing blood pressure. Furthermore, ROMKi B provided beneficial effects on both the plasma lipid profile and bone mineral density. Chronic ROMK inhibition not only prevented but also reversed the development of hypertension and end-organ damage in Dahl salt-sensitive rats. Our findings suggest a potential utility of ROMKi B as a novel antihypertensive agent, particularly for the treatment of the salt-sensitive hypertension patient population. © 2016 American Heart Association, Inc.
Berton, Paula; Di Bona, Kristin R; Yancey, Denise; Rizvi, Syed A A; Gray, Marquita; Gurau, Gabriela; Shamshina, Julia L; Rasco, Jane F; Rogers, Robin D
2017-05-11
Tuning the bioavailability of lidocaine was explored by its incorporation into the ionic liquid lidocainium docusate ([Lid][Doc]) and the deep eutectic Lidocaine·Ibuprofen (Lid·Ibu) and comparing the transdermal absorption of these with the crystalline salt lidocainium chloride ([Lid]Cl). Each form of lidocaine was dissolved in a vehicle cream and topically applied to Sprague-Dawley rats. The concentrations of the active pharmaceutical ingredients (APIs) in blood plasma were monitored over time as an indication of systemic absorption. The concentration of lidocaine in plasma varied between applied API-based creams, with faster and higher systemic absorption of the hydrogen bonded deep eutectic Lid·Ibu than the absorption of the salts [Lid]Cl or [Lid][Doc]. Interestingly, a differential transdermal absorption was observed between lidocaine and ibuprofen when Lid·Ibu was applied, possibly indicating different interactions with the tissue components.
2017-01-01
Tuning the bioavailability of lidocaine was explored by its incorporation into the ionic liquid lidocainium docusate ([Lid][Doc]) and the deep eutectic Lidocaine·Ibuprofen (Lid·Ibu) and comparing the transdermal absorption of these with the crystalline salt lidocainium chloride ([Lid]Cl). Each form of lidocaine was dissolved in a vehicle cream and topically applied to Sprague–Dawley rats. The concentrations of the active pharmaceutical ingredients (APIs) in blood plasma were monitored over time as an indication of systemic absorption. The concentration of lidocaine in plasma varied between applied API-based creams, with faster and higher systemic absorption of the hydrogen bonded deep eutectic Lid·Ibu than the absorption of the salts [Lid]Cl or [Lid][Doc]. Interestingly, a differential transdermal absorption was observed between lidocaine and ibuprofen when Lid·Ibu was applied, possibly indicating different interactions with the tissue components. PMID:28523100
NASA Technical Reports Server (NTRS)
Collins, J. J.; De Luca, C. J.; Pavlik, A. E.; Roy, S. H.; Emley, M. S.; Young, L. R. (Principal Investigator)
1995-01-01
Stabilogram-diffusion analysis was used to examine how prolonged periods in microgravity affect the open-loop and closed-loop postural control mechanisms. It was hypothesized that following spaceflight: (1) the effective stochastic activity of the open-loop postural control schemes in astronauts is increased; (2) the effective stochastic activity and uncorrelated behavior, respectively, of the closed-loop postural control mechanisms in astronauts are increased; and (3) astronauts utilized open-loop postural controls schemes for shorter time intervals and smaller displacements. Four crew members and two alternates from the 14-day Spacelab Life Sciences 2 Mission were included in the study. Each subject was tested under eyes-open, quiet-standing conditions on multiple preflight and postflight days. The subjects' center-of-pressure trajectories were measured with a force platform and analyzed according to stabilogram-diffusion analysis. It was found that the effective stochastic activity of the open-loop postural control schemes in three of the four crew members was increased following spaceflight. This result is interpreted as an indication that there may be in-flight adaptations to higher-level descending postural control pathways, e.g., a postflight increase in the tonic activation of postural muscles. This change may also be the consequence of a compensatory (e.g., "stiffening") postural control strategy that is adopted by astronauts to account for general feeling of postflight unsteadiness. The crew members, as a group, did not exhibit any consistent preflight/postflight differences in the steady-state behavior of their closed-loop postural control mechanisms or in the functional interaction of their open-loop and closed-loop postural control mechanisms. These results are interpreted as indications that although there may be in-flight adaptations to the vestibular system and/or proprioceptive system, input from the visual system can compensate for such changes
Fei, Juntao; Lu, Cheng
2018-04-01
In this paper, an adaptive sliding mode control system using a double loop recurrent neural network (DLRNN) structure is proposed for a class of nonlinear dynamic systems. A new three-layer RNN is proposed to approximate unknown dynamics with two different kinds of feedback loops where the firing weights and output signal calculated in the last step are stored and used as the feedback signals in each feedback loop. Since the new structure has combined the advantages of internal feedback NN and external feedback NN, it can acquire the internal state information while the output signal is also captured, thus the new designed DLRNN can achieve better approximation performance compared with the regular NNs without feedback loops or the regular RNNs with a single feedback loop. The new proposed DLRNN structure is employed in an equivalent controller to approximate the unknown nonlinear system dynamics, and the parameters of the DLRNN are updated online by adaptive laws to get favorable approximation performance. To investigate the effectiveness of the proposed controller, the designed adaptive sliding mode controller with the DLRNN is applied to a -axis microelectromechanical system gyroscope to control the vibrating dynamics of the proof mass. Simulation results demonstrate that the proposed methodology can achieve good tracking property, and the comparisons of the approximation performance between radial basis function NN, RNN, and DLRNN show that the DLRNN can accurately estimate the unknown dynamics with a fast speed while the internal states of DLRNN are more stable.
Integrand reduction for two-loop scattering amplitudes through multivariate polynomial division
NASA Astrophysics Data System (ADS)
Mastrolia, Pierpaolo; Mirabella, Edoardo; Ossola, Giovanni; Peraro, Tiziano
2013-04-01
We describe the application of a novel approach for the reduction of scattering amplitudes, based on multivariate polynomial division, which we have recently presented. This technique yields the complete integrand decomposition for arbitrary amplitudes, regardless of the number of loops. It allows for the determination of the residue at any multiparticle cut, whose knowledge is a mandatory prerequisite for applying the integrand-reduction procedure. By using the division modulo Gröbner basis, we can derive a simple integrand recurrence relation that generates the multiparticle pole decomposition for integrands of arbitrary multiloop amplitudes. We apply the new reduction algorithm to the two-loop planar and nonplanar diagrams contributing to the five-point scattering amplitudes in N=4 super Yang-Mills and N=8 supergravity in four dimensions, whose numerator functions contain up to rank-two terms in the integration momenta. We determine all polynomial residues parametrizing the cuts of the corresponding topologies and subtopologies. We obtain the integral basis for the decomposition of each diagram from the polynomial form of the residues. Our approach is well suited for a seminumerical implementation, and its general mathematical properties provide an effective algorithm for the generalization of the integrand-reduction method to all orders in perturbation theory.