Science.gov

Sample records for cold flow improvers

  1. Improving the cold flow properties of biodiesel by skeletal isomerization of fatty acid chains

    USDA-ARS?s Scientific Manuscript database

    Biodiesel is defined as the mono-alkyl fatty acid esters made from vegetable oil or animal fat lipids. Despite its many advantages, biodiesel from most lipid feedstocks has generally poor cold flow properties. The present study evaluates the fuel related properties of branched-chain fatty acid methy...

  2. Cold Flow Verification Test Facility

    SciTech Connect

    Shamsi, A.; Shadle, L.J.

    1996-12-31

    The cold flow verification test facility consists of a 15-foot high, 3-foot diameter, domed vessel made of clear acrylic in two flanged sections. The unit can operate up to pressures of 14 psig. The internals include a 10-foot high jetting fluidized bed, a cylindrical baffle that hangs from the dome, and a rotating grate for control of continuous solids removal. The fluid bed is continuously fed solids (20 to 150 lb/hr) through a central nozzle made up of concentric pipes. It can either be configured as a half or full cylinder of various dimensions. The fluid bed has flow loops for separate air flow control for conveying solids (inner jet, 500 to 100000 scfh) , make-up into the jet (outer jet, 500 to 8000 scfh), spargers in the solids removal annulus (100 to 2000 scfh), and 6 air jets (20 to 200 scfh) on the sloping conical grid. Additional air (500 to 10000 scfh) can be added to the top of the dome and under the rotating grate. The outer vessel, the hanging cylindrical baffles or skirt, and the rotating grate can be used to study issues concerning moving bed reactors. There is ample allowance for access and instrumentation in the outer shell. Furthermore, this facility is available for future Cooperative Research and Development Program Manager Agreements (CRADA) to study issues and problems associated with fluid- and fixed-bed reactors. The design allows testing of different dimensions and geometries.

  3. Resource Prospector Propulsion Cold Flow Test

    NASA Technical Reports Server (NTRS)

    Williams, Hunter; Pederson, Kevin; Dervan, Melanie; Holt, Kimberly; Jernigan, Frankie; Trinh, Huu; Flores, Sam

    2014-01-01

    For the past year, NASA Marshall Space Flight Center and Johnson Space Center have been working on a government version of a lunar lander design for the Resource Prospector Mission. A propulsion cold flow test system, representing an early flight design of the propulsion system, has been fabricated. The primary objective of the cold flow test is to simulate the Resource Prospector propulsion system operation through water flow testing and obtain data for anchoring analytical models. This effort will also provide an opportunity to develop a propulsion system mockup to examine hardware integration to a flight structure. This paper will report the work progress of the propulsion cold flow test system development and test preparation. At the time this paper is written, the initial waterhammer testing is underway. The initial assessment of the test data suggests that the results are as expected and have a similar trend with the pretest prediction. The test results will be reported in a future conference.

  4. LADEE Propulsion System Cold Flow Test

    NASA Technical Reports Server (NTRS)

    Williams, Jonathan Hunter; Chapman, Jack M.; Trinh, Hau, P.; Bell, James H.

    2013-01-01

    Lunar Atmosphere and Dust Environment Explorer (LADEE) is a NASA mission that will orbit the Moon. Its main objective is to characterize the atmosphere and lunar dust environment. The spacecraft development is being led by NASA Ames Research Center and scheduled for launch in 2013. The LADEE spacecraft will be operated with a bi-propellant hypergolic propulsion system using MMH and NTO as the fuel and oxidizer, respectively. The propulsion system utilizes flight-proven hardware on major components. The propulsion layout is composed of one 100-lbf main thruster and four 5-lbf RCS thrusters. The propellants are stored in four tanks (two parallel-connected tanks per propellant component). The propellants will be pressurized by regulated helium. A simulated propulsion system has been built for conducting cold flow test series to characterize the transient fluid flow of the propulsion system feed lines and to verify the critical operation modes, such as system priming, waterhammer, and crucial mission duty cycles. Propellant drainage differential between propellant tanks will also be assessed. Since the oxidizer feed line system has a higher flow demand than the fuel system does, the cold flow test focuses on the oxidizer system. The objective of the cold flow test is to simulate the LADEE propulsion fluid flow operation through water cold flow test and to obtain data for anchoring analytical models. The models will be used to predict the transient and steady state flow behaviors in the actual flight operations. The test activities, including the simulated propulsion test article, cold flow test, and analytical modeling, are being performed at NASA Marshall Space Flight Center. At the time of the abstract submission, the test article checkout is being performed. The test series will be completed by November, 2012

  5. 1. COLD FLOW LABORATORY, VIEW TOWARDS EAST. Glenn L. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    1. COLD FLOW LABORATORY, VIEW TOWARDS EAST. - Glenn L. Martin Company, Titan Missile Test Facilities, Cold Flow Laboratory Building B, Waterton Canyon Road & Colorado Highway 121, Lakewood, Jefferson County, CO

  6. 2. COLD FLOW LABORATORY, VIEW TOWARDS NORTH. Glenn L. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    2. COLD FLOW LABORATORY, VIEW TOWARDS NORTH. - Glenn L. Martin Company, Titan Missile Test Facilities, Cold Flow Laboratory Building B, Waterton Canyon Road & Colorado Highway 121, Lakewood, Jefferson County, CO

  7. Improving cold chain systems: Challenges and solutions.

    PubMed

    Ashok, Ashvin; Brison, Michael; LeTallec, Yann

    2017-04-19

    While a number of new vaccines have been rolled out across the developing world (with more vaccines in the pipeline), cold chain systems are struggling to efficiently support national immunization programs in ensuring the availability of safe and potent vaccines. This article reflects on the Clinton Health Access Initiative, Inc. (CHAI) experience working since 2010 with national immunization programs and partners to improve vaccines cold chains in 10 countries-Ethiopia, Nigeria, Kenya, Malawi, Tanzania, Uganda, Cameroon, Mozambique, Lesotho and India - to identify the root causes and solutions for three common issues limiting cold chain performance. Key recommendations include: Collectively, the solutions detailed in this article chart a path to substantially improving the performance of the cold chain. Combined with an enabling global and in-country environment, it is possible to eliminate cold chain issues as a substantial barrier to effective and full immunization coverage over the next few years. Copyright © 2017. Published by Elsevier Ltd.

  8. COLD FLOWS AND THE FIRST QUASARS

    SciTech Connect

    Di Matteo, T.; Khandai, N.; DeGraf, C.; Feng, Y.; Croft, R. A. C.; Lopez, J.; Springel, V.

    2012-02-15

    Observations of the most distant bright quasars imply that billion solar mass supermassive black holes (SMBHs) have to be assembled within the first 800 million years. Under our standard galaxy formation scenario such fast growth implies large gas densities providing sustained accretion at critical or supercritical rates onto an initial black hole seed. It has been a long standing question whether and how such high black hole accretion rates can be achieved and sustained at the centers of early galaxies. Here we use our new MassiveBlack cosmological hydrodynamic simulation covering a volume (0.75 Gpc){sup 3} appropriate for studying the rare first quasars to show that steady high density cold gas flows responsible for assembling the first galaxies produce the high gas densities that lead to sustained critical accretion rates and hence rapid growth commensurate with the existence of {approx}10{sup 9} M{sub Sun} black holes as early as z {approx} 7. We find that under these conditions quasar feedback is not effective at stopping the cold gas from penetrating the central regions and hence cannot quench the accretion until the host galaxy reaches M{sub halo} > or approx. 10{sup 1}2{sup M}{sub Sun }. This cold-flow-driven scenario for the formation of quasars implies that they should be ubiquitous in galaxies in the early universe and that major (proto)galaxy mergers are not a requirement for efficient fuel supply and growth, particularly for the earliest SMBHs.

  9. Slurry fired heater cold-flow modelling

    SciTech Connect

    Moujaes, S.F.

    1983-07-01

    This report summarizes the experimental and theoretical work leading to the scale-up of the SRC-I Demonstration Plant slurry fired heater. The scale-up involved a theoretical model using empirical relations in the derivation, and employed variables such as flow conditions, liquid viscosity, and slug frequency. Such variables have been shown to affect the heat transfer characteristics ofthe system. The model assumes that, if all other variables remain constant, the heat transfer coefficient can be scaled up proportional to D/sup -2/3/ (D = inside diameter of the fired heater tube). All flow conditions, liquid viscosities, and pipe inclinations relevant to the demonstration plant have indicated a slug flow regime in the slurry fired heater. The annular and stratified flow regimes should be avoided to minimize the potential for excessive pipe erosion and to decrease temperature gradients along the pipe cross section leading to coking and thermal stresses, respectively. Cold-flow studies in 3- and 6.75-in.-inside-diameter (ID) pipes were conducted to determine the effect of scale-up on flow regime, slug frequency, and slug dimensions. The developed model assumes that conduction heat transfer occurs through the liquid film surrounding the gas slug and laminar convective heat transfer to the liquid slug. A weighted average of these two heat transfer mechanisms gives a value for the average pipe heat transfer coefficient. The cold-flow work showed a decrease in the observed slug frequency between the 3- and 6.75-ID pipes. Data on the ratio of gas to liquid slug length in the 6.75-in. pipe are not yet complete, but are expected to yield generally lower values than those obtained in the 3-in. pipe; this will probably affect the scale-up to demonstration plant conditions. 5 references, 15 figures, 7 tables.

  10. Improvements in Cold-Plate Fabrication

    NASA Technical Reports Server (NTRS)

    Zaffetti, Mark A.; Taddey, Edmund P.; Laurin, Michael B.; Chabebe, Natalia

    2012-01-01

    Five improvements are reported in cold-plate fabrication. This cold plate is part of a thermal control system designed to serve on space missions. The first improvement is the merging of the end sheets of the cold plate with the face sheets of the structural honeycomb panel. The cold plate, which can be a brazed assembly, uses the honeycomb face sheet as its end sheet. Thus, when the honeycomb panel is fabricated, the face sheet that is used is already part of the cold plate. In addition to reducing weight, costs, and steps, the main benefit of this invention is that it creates a more structurally sound assembly. The second improvement involves incorporation of the header into the closure bar to pass the fluid to a lower layer. Conventional designs have used a separate header, which increases the geometry of the system. The improvement reduces the geometry, thus allowing the cold plate to fit into smaller area. The third improvement eliminates the need of hose, tube, or manifold to supply the cooling fluid externally. The external arrangement can be easily damaged and is vulnerable to leakage. The new arrangement incorporates an internal fluid transfer tube. This allows the fluid to pass from one cold plate to the other without any exposed external features. The fourth improvement eliminates separate fabrication of cold plate(s) and structural members followed by a process of attaching them to each other. Here, the structural member is made of material that can be brazed just as that of the cold plate. Now the structural member and the cold plate can be brazed at the same time, creating a monolithic unit, and thus a more structurally sound assembly. Finally, the fifth improvement is the elimination of an additional welding step that can damage the braze joints. A tube section, which is usually welded on after the braze process, is replaced with a more structurally sound configuration that can be brazed at the same time as the rest of the cold plate.

  11. Dual throat thruster cold flow analysis

    NASA Technical Reports Server (NTRS)

    Lundgreen, R. B.; Nickerson, G. R.; Obrien, C. J.

    1978-01-01

    The concept was evaluated with cold flow (nitrogen gas) testing and through analysis for application as a tripropellant engine for single-stage-to-orbit type missions. Three modes of operation were tested and analyzed: (1) Mode 1 Series Burn, (2) Mode 1 Parallel Burn, and (3) Mode 2. Primary emphasis was placed on the Mode 2 plume attachment aerodynamics and performance. The conclusions from the test data analysis are as follows: (1) the concept is aerodynamically feasible, (2) the performance loss is as low as 0.5 percent, (3) the loss is minimized by an optimum nozzle spacing corresponding to an AF-ATS ratio of about 1.5 or an Le/Rtp ratio of 3.0 for the dual throat hardware tested, requiring only 4% bleed flow, (4) the Mode 1 and Mode 2 geometry requirements are compatible and pose no significant design problems.

  12. Cold Flow Propulsion Test Complex Pulse Testing

    NASA Technical Reports Server (NTRS)

    McDougal, Kris

    2016-01-01

    When the propellants in a liquid rocket engine burn, the rocket not only launches and moves in space, it causes forces that interact with the vehicle itself. When these interactions occur under specific conditions, the vehicle's structures and components can become unstable. One instability of primary concern is termed pogo (named after the movement of a pogo stick), in which the oscillations (cycling movements) cause large loads, or pressure, against the vehicle, tanks, feedlines, and engine. Marshall Space Flight Center (MSFC) has developed a unique test technology to understand and quantify the complex fluid movements and forces in a liquid rocket engine that contribute strongly to both engine and integrated vehicle performance and stability. This new test technology was established in the MSFC Cold Flow Propulsion Test Complex to allow injection and measurement of scaled propellant flows and measurement of the resulting forces at multiple locations throughout the engine.

  13. Resource Prospector Propulsion System Cold Flow Testing

    NASA Technical Reports Server (NTRS)

    Williams, Hunter; Holt, Kim; Addona, Brad; Trinh, Huu

    2015-01-01

    Resource Prospector (RP) is a NASA mission being led by NASA Ames Research Center with current plans to deliver a scientific payload package aboard a rover to the lunar surface. As part of an early risk reduction activity, Marshall Space Flight Center (MSFC) and Johnson Space Flight Center (JSC) have jointly developed a government-version concept of a lunar lander for the mission. The spacecraft consists of two parts, the lander and the rover which carries the scientific instruments. The lander holds the rover during launch, cruise, and landing on the surface. Following terminal descent and landing the lander portion of the spacecraft become dormant after the rover embarks on the science mission. The lander will be equipped with a propulsion system for lunar descent and landing, as well as trajectory correction and attitude control maneuvers during transit to the moon. Hypergolic propellants monomethyl hydrazine and nitrogen tetroxide will be used to fuel sixteen 70-lbf descent thrusters and twelve 5-lbf attitude control thrusters. A total of four metal-diaphragm tanks, two per propellant, will be used along with a high-pressure composite-overwrapped pressure vessel for the helium pressurant gas. Many of the major propulsion system components are heritage missile hardware obtained by NASA from the Air Force. In parallel with the flight system design activities, a simulated propulsion system based on flight drawings was built for conducting a series of water flow tests to characterize the transient fluid flow of the propulsion system feed lines and to verify the critical operation modes such as system priming, waterhammer, and crucial mission duty cycles. The primary objective of the cold flow testing was to simulate the RP propulsion system fluid flow operation through water flow testing and to obtain data for anchoring analytical models. The models will be used to predict the transient and steady state flow behaviors in the actual flight operations. All design and

  14. Temperature and pressure measurements at cold exit of counter-flow vortex tube with flow visualization of reversed flow

    NASA Astrophysics Data System (ADS)

    Yusof, Mohd Hazwan bin; Katanoda, Hiroshi; Morita, Hiromitsu

    2015-02-01

    In order to clarify the structure of the cold flow discharged from the counter-flow vortex tube (VT), the temperature and pressure of the cold flow were measured, and the existence and behavior of the reversed flow at the cold exit was studied using a simple flow visualization technique consisting of a 0.75mm-diameter needle, and an oil paint droplet. It is observed through this experiment that the Pitot pressure at the cold exit center can either be lower or higher than atmospheric pressure, depending on the inlet pressure and the cold fraction, and that a reversed flow is observed when the Pitot pressure at the cold exit center is lower than atmospheric pressure. In addition, it is observed that when reducing the cold fraction from unity at any arbitrary inlet pressure, the region of reversed and colder flow in the central part of cold exit extends in the downstream direction.

  15. 2. CATCH BASIN, INFLOW PIPES AT CENTER, COLD FLOW LABORATORY ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    2. CATCH BASIN, INFLOW PIPES AT CENTER, COLD FLOW LABORATORY AT LEFT, VIEW TOWARDS NORTHWEST. - Glenn L. Martin Company, Titan Missile Test Facilities, Catch Basin, Waterton Canyon Road & Colorado Highway 121, Lakewood, Jefferson County, CO

  16. Evolution of velocity dispersion along cold collisionless flows

    SciTech Connect

    Banik, Nilanjan; Sikivie, Pierre

    2016-05-01

    We found that the infall of cold dark matter onto a galaxy produces cold collisionless flows and caustics in its halo. If a signal is found in the cavity detector of dark matter axions, the flows will be readily apparent as peaks in the energy spectrum of photons from axion conversion, allowing the densities, velocity vectors and velocity dispersions of the flows to be determined. We also discuss the evolution of velocity dispersion along cold collisionless flows in one and two dimensions. A technique is presented for obtaining the leading behaviour of the velocity dispersion near caustics. The results are used to derive an upper limit on the energy dispersion of the Big Flow from the sharpness of its nearby caustic, and a prediction for the dispersions in its velocity components.

  17. Evolution of velocity dispersion along cold collisionless flows

    DOE PAGES

    Banik, Nilanjan; Sikivie, Pierre

    2016-05-01

    We found that the infall of cold dark matter onto a galaxy produces cold collisionless flows and caustics in its halo. If a signal is found in the cavity detector of dark matter axions, the flows will be readily apparent as peaks in the energy spectrum of photons from axion conversion, allowing the densities, velocity vectors and velocity dispersions of the flows to be determined. We also discuss the evolution of velocity dispersion along cold collisionless flows in one and two dimensions. A technique is presented for obtaining the leading behaviour of the velocity dispersion near caustics. The results aremore » used to derive an upper limit on the energy dispersion of the Big Flow from the sharpness of its nearby caustic, and a prediction for the dispersions in its velocity components.« less

  18. Evolution of velocity dispersion along cold collisionless flows

    SciTech Connect

    Banik, Nilanjan; Sikivie, Pierre

    2016-05-01

    We found that the infall of cold dark matter onto a galaxy produces cold collisionless flows and caustics in its halo. If a signal is found in the cavity detector of dark matter axions, the flows will be readily apparent as peaks in the energy spectrum of photons from axion conversion, allowing the densities, velocity vectors and velocity dispersions of the flows to be determined. We also discuss the evolution of velocity dispersion along cold collisionless flows in one and two dimensions. A technique is presented for obtaining the leading behaviour of the velocity dispersion near caustics. The results are used to derive an upper limit on the energy dispersion of the Big Flow from the sharpness of its nearby caustic, and a prediction for the dispersions in its velocity components.

  19. Improved cold tolerance and its mechanism in cold-acclimated rats by high fat diet feeding.

    PubMed

    Kuroshima, A; Doi, K; Yahata, T; Ohno, T

    1977-08-01

    Cold tolerance and metabolic responses to cold were studied in cold-acclimated rats on high fat diet (CAHF). Cold tolerance at-5 degrees C was assessed by fall of colonic temperature of clipped rats after 18 h of fasting. Rate of fall in colonic temperature was greatest in warm-acclimated control rats (WAST), slowest in cold-acclimated rats on standard diet (CAST), and remained unchanged in CAHF during cold exposure for 240 min. Increment in blood free fatty acid (FFA) concentration 80 min after cold exposure was greatest in WAST, less in CAST, and least in CAHF. Blood glucose decreased similarly in WAST and CAST after cold exposure, while it remained unchanged in CAHF. Blood beta-hydroxybutyrate also increased similarly in WAST and CAST, while it did not change in CAHF. Nonshivering thermogenesis tested by noradrenaline was greatest in CAHF, followed by CAST and WAST. Shivering induced by cold exposure was less pronounced in CAST than in WAST and did not develop in CAHF; changes in colonic temperature were inversely related to the extent of shivering during cold exposure for 90 min. These results suggest that an integrating effect of cold and high fat diet could improve cold tolerance much more than cold acclimation itself, possibly through enhanced nonshivering thermogenesis caused by metabolic modifications such as increased lipid use and gluconeogenesis.

  20. Numerical Study of Unsteady Flow in Centrifugal Cold Compressor

    NASA Astrophysics Data System (ADS)

    Zhang, Ning; Zhang, Peng; Wu, Jihao; Li, Qing

    In helium refrigeration system, high-speed centrifugal cold compressor is utilized to pumped gaseous helium from saturated liquid helium tank at low temperature and low pressure for producing superfluid helium or sub-cooled helium. Stall and surge are common unsteady flow phenomena in centrifugal cold compressors which severely limit operation range and impact efficiency reliability. In order to obtain the installed range of cold compressor, unsteady flow in the case of low mass flow or high pressure ratio is investigated by the CFD. From the results of the numerical analysis, it can be deduced that the pressure ratio increases with the decrease in reduced mass flow. With the decrease of the reduced mass flow, backflow and vortex are intensified near the shroud of impeller. The unsteady flow will not only increase the flow loss, but also damage the compressor. It provided a numerical foundation of analyzing the effect of unsteady flow field and reducing the flow loss, and it is helpful for the further study and able to instruct the designing.

  1. Cold plasma processing to improve food safety

    USDA-ARS?s Scientific Manuscript database

    Cold plasma is an antimicrobial process being developed for application as a food processing technology. This novel intervention is the subject of an expanding research effort by groups around the world. A variety of devices can be used to generate cold plasma and apply it to the food commodity bein...

  2. Cold molecular gas in cooling flow clusters of galaxies

    NASA Astrophysics Data System (ADS)

    Salomé, P.; Combes, F.

    2003-12-01

    The results of a CO line survey in central cluster galaxies with cooling flows are presented. Cold molecular gas is detected with the IRAM 30 m telescope, through CO(1-0) and CO(2-1) emission lines in 6-10 among 32 galaxies. The corresponding gas masses are between 3*E8 and 4*E10 Msun. These results are in agreement with recent CO detections by \\cite{Edg01}. A strong correlation between the CO emission and the Hα luminosity is also confirmed. Cold gas exists in the center of cooling flow clusters and these detections may be interpreted as evidence of the long searched for very cold residual of the hot cooling gas. Tables 1-4 are also available at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/412/657

  3. Mitigating cold flow problems of biodiesel: Strategies with additives

    NASA Astrophysics Data System (ADS)

    Mohanan, Athira

    The present thesis explores the cold flow properties of biodiesel and the effect of vegetable oil derived compounds on the crystallization path as well as the mechanisms at play at different stages and length scales. Model systems including triacylglycerol (TAG) oils and their derivatives, and a polymer were tested with biodiesel. The goal was to acquire the fundamental knowledge that would help design cold flow improver (CFI) additives that would address effectively and simultaneously the flow problems of biodiesel, particularly the cloud point (CP) and pour point (PP). The compounds were revealed to be fundamentally vegetable oil crystallization modifiers (VOCM) and the polymer was confirmed to be a pour point depressant (PPD). The results obtained with the VOCMs indicate that two cis-unsaturated moieties combined with a trans-/saturated fatty acid is a critical structural architecture for depressing the crystallization onset by a mechanism wherein while the straight chain promotes a first packing with the linear saturated FAMEs, the kinked moieties prevent further crystallization. The study of model binary systems made of a VOCM and a saturated FAME with DSC, XRD and PLM provided a complete phase diagram including the thermal transformation lines, crystal structure and microstructure that impact the phase composition along the different crystallization stages, and elicited the competing effects of molecular mass, chain length mismatch and isomerism. The liquid-solid boundary is discussed in light of a simple thermodynamic model based on the Hildebrand equation and pair interactions. In order to test for synergies, the PP and CP of a biodiesel (Soy1500) supplemented with several VOCM and PLMA binary cocktails were measured using a specially designed method inspired by ASTM standards. The results were impressive, the combination of additives depressed CP and PP better than any single additive. The PLM and DSC results suggest that the cocktail additives are most

  4. Fluctuating Pressure Data from 2-D Nozzle Cold Flow Tests (Dual Bell)

    NASA Technical Reports Server (NTRS)

    Nesman, Tomas E.

    2001-01-01

    Rocket engines nozzle performance changes as a vehicle climbs through the atmosphere. An altitude compensating nozzle, ACN, is intended to improve on a fixed geometry bell nozzle that performs at optimum at only one trajectory point. In addition to nozzle performance, nozzle transient loads are an important consideration. Any nozzle experiences large transient toads when shocks pass through the nozzle at start and shutdown. Additional transient toads will occur at transitional flow conditions. The objectives of cold flow nozzle testing at MSFC are CFD benchmark / calibration and Unsteady flow / sideloads. Initial testing performed with 2-D inserts to 14" transonic wind tunnel. Recent review of 2-D data in preparation for nozzle test facility 3-D testing. This presentation shows fluctuating pressure data and some observations from 2-D dual-bell nozzle cold flow tests.

  5. Improving the cold chain for vaccines.

    PubMed

    Lloyd, J S

    1977-01-01

    The cold chain may be defined as a system for transporting and storing vaccines at very low temperataures, particularly in tropical countries. In Ghana, efforts are being made, with the assistance of the World Health Organization (WHO) to develop and test a new cold chain technology. Emphasis is on local production in order to meet the needs of the countrywide immunization program, and, if possible, of similar programs in other West African nations. Focus in this discussion is on the losses resulting from mishandling of vaccines during storage and in transit through various stages in the cold chain as well as the problems, requirements, and proposed solutions. In most countries with immunization programs, breakdowns in refrigeration during the transport and storage of vaccines in remote rural areas or at the regional and national central stores have led to great losses of vaccine. The losses are often caused by inappropriate management and technology. The most promising recent development in the area of storage is an enzyme-based time/temperature indicator contained in a paper tab which is attached to the vaccine packet. In order to reduce to a minimum the handling of vaccines at the national central store it is proposed that the ministry of health submit details of regional requirements in their requisition to the manufacturer. Then the manufacturer can make presealed packages which are dispatched by air to the national central store and from there to the regions, while they are still sealed. Insulated boxes for this purpose have been tested in Sweden and been shown to maintain deep-freezing temperatures for 5 days. Road communications to the regional centers are good in Ghana and the 5-day cold boxes give adequate safety margins. The plan for the immunization program in Ghana is to employ a combination of teams from both fixed and mobile centers. 3 contacts, 3 months apart, will be made by the fixed teams; mobile teams will make 2 contacts, 2 months apart. Mobile

  6. Cold air drainage flows subsidize montane valley ecosystem productivity.

    PubMed

    Novick, Kimberly A; Oishi, A Christopher; Miniat, Chelcy Ford

    2016-12-01

    In mountainous areas, cold air drainage from high to low elevations has pronounced effects on local temperature, which is a critical driver of many ecosystem processes, including carbon uptake and storage. Here, we leverage new approaches for interpreting ecosystem carbon flux observations in complex terrain to quantify the links between macro-climate condition, drainage flows, local microclimate, and ecosystem carbon cycling in a southern Appalachian valley. Data from multiple long-running climate stations and multiple eddy covariance flux towers are combined with simple models for ecosystem carbon fluxes. We show that cold air drainage into the valley suppresses local temperature by several degrees at night and for several hours before and after sunset, leading to reductions in growing season respiration on the order of ~8%. As a result, we estimate that drainage flows increase growing season and annual net carbon uptake in the valley by >10% and >15%, respectively, via effects on microclimate that are not be adequately represented in regional- and global-scale terrestrial ecosystem models. Analyses driven by chamber-based estimates of soil and plant respiration reveal cold air drainage effects on ecosystem respiration are dominated by reductions to the respiration of aboveground biomass. We further show that cold air drainage proceeds more readily when cloud cover and humidity are low, resulting in the greatest enhancements to net carbon uptake in the valley under clear, cloud-free (i.e., drought-like) conditions. This is a counterintuitive result that is neither observed nor predicted outside of the valley, where nocturnal temperature and respiration increase during dry periods. This result should motivate efforts to explore how topographic flows may buffer eco-physiological processes from macroscale climate change. © 2016 John Wiley & Sons Ltd.

  7. A Newly Forming Cold Flow Protogalactic Disk, a Signature of Cold Accretion from the Cosmic Web

    NASA Astrophysics Data System (ADS)

    Martin, D. Christopher; Matuszewski, Mateusz; Morrissey, Patrick; Neill, James D.; Moore, Anna; Steidel, Charles C.; Trainor, Ryan

    2016-06-01

    How galaxies form from, and are fueled by, gas from the intergalactic medium (IGM) remains one of the major unsolved problems in galaxy formation. While the classical Cold Dark Matter paradigm posits galaxies forming from cooling virialized gas, recent theory and numerical simulations have highlighted the importance of cold accretion flows—relatively cool (T ˜ few × 104 K) unshocked gas streaming along filaments into dark matter halos, including hot, massive, high-redshift halos. These flows are thought to deposit gas and angular momentum into the circumgalactic medium resulting in disk- or ring-like structures, eventually coalescing into galaxies forming at filamentary intersections. We earlier reported a bright, Lyα emitting filament near the QSO HS1549+19 at redshift z = 2.843 discovered with the Palomar Cosmic Web Imager. We now report that the bright part of this filament is an enormous (R > 100 kpc) rotating structure of hydrogen gas with a disk-like velocity profile consistent with a 4 × 1012 M ⊙ halo. The orbital time of the outer part of the what we term a “protodisk” is comparable to the virialization time and the age of the universe at this redshift. We propose that this protodisk can only have recently formed from cold gas flowing directly from the cosmic web.

  8. Flow Regime Transition in Inner Grooved Minichannel Cold Plates for Cooling Hybrid Electric Power Electronics

    DTIC Science & Technology

    2013-01-01

    3. Hydroblok pressure-fit 6-pass serpentine cold plate (9)..................................................5 Figure 4. Two-phase flow regimes and...however, may be to integrate the enhanced tubes in a pressure-fit serpentine brazed cold plate. An example of this cold plate design is shown in...figure 3. Figure 3. Hydroblok pressure-fit 6-pass serpentine cold plate (9). 2.1 Two-phase Flow Regimes In two-phase flow, the vapor and liquid

  9. Alpine Valley Flows and Cold Pools during T-REX

    NASA Astrophysics Data System (ADS)

    Calhoun, R.; Christman, A.; Retallack, C.; Fernando, H.

    2009-04-01

    Coherent Doppler lidar data and sodar/RASS profiles are used to study the evolution of nocturnal flows and cold pools in an alpine valley. Owens Valley, California was the site of the Terrain-Induced Rotor Experiment (T-REX) carried out during the months of March and April of 2006. The main objective of this experimental campaign was the observation of mountain wave and rotor activity in the lee of the Sierra Nevada Mountains. However, the opportunity existed during non-rotor events to focus on the stable boundary layer, as well as the creation and depletion of cold air pools. The unique local topography, set between two large and nearly parallel mountain ranges, offered the opportunity to study diurnal flow phenomena in an idealized valley setting. ASU deployed its coherent Doppler lidar during T-REX, in addition to a flux tower and a sodar/RASS. The presence of a second scanning coherent Doppler lidar situated near the ASU Doppler lidar, provided the opportunity to utilize a dual Doppler retrieval technique ("virtual towers") which was developed during the Joint Urban Dispersion Experiment (JU2003). The second Doppler lidar was deployed and operated by the Deutsches Zentrum fur Luft- und Raumfahrt (DLR). Wind directions are frequently along the valley during more quiescent conditions, and several examples are given. In one case, there was a significant night-time drainage flow occuring with wind velocity magnitudes greater than 10m/s on vertical profiles obtained through dual-Doppler analysis. For this case, the velocity profile evolved gradually from a relatively smooth vertical velocity profile to a vertical velocity profile characterized by several local maxima. A low-level jet was seen below 500 m above ground level. Regarding cold pools during T-REX, some differences are noted with the classical expectations due to the complexity of the flow configuration considered here. In particular, classical cold pool destruction scenarios do not usually take into

  10. Improving Seed Germination and Peanut Yields by Cold Plasma Treatment

    NASA Astrophysics Data System (ADS)

    Li, Ling; Li, Jiangang; Shen, Minchong; Hou, Jinfeng; Shao, Hanliang; Dong, Yuanhua; Jiang, Jiafeng

    2016-10-01

    This study explored the effects of cold plasma treatment on seed germination, plant growth, and peanut yield. Cold plasma treatment improved germination and seedling growth, and the 120 W treatment produced the best effect. Germination potential and germination rate were markedly raised by 150% and 21%, respectively. Germination was accelerated and the uniformity of emergence improved. The apparent contact angle was decreased by 53%. Seedling shoot and root dry weights increased by 11% and 9%. Leaf area, leaf thickness, leaf nitrogen concentration, chlorophyll contents, and dry weight at the fruiting stage, together with plant height, stem diameter, and root dry weight at the mature stage were all markedly raised by the cold plasma treatment. The cold plasma treatment enhanced yield components, such as branch numbers per plant, pod numbers per plant, and 100 pod weights by 8%, 13%, and 9%, respectively, compared to the control. Furthermore, the yield improved by 10%. These results suggested that cold plasma treatment improved germination, plant growth, and yield, which might be due to the cold plasma increasing the leaf area, nitrogen concentrations, and chlorophyll contents. supported by National Key Technology Research and Development Program of the Ministry of Science and Technology of China (No. 2012BAD05B04), National Natural Science Foundation of China (No. 41201241), “Strategic Priority Research Program” of the Chinese Academy of Sciences (No. XDB15030301) and Jiangsu Province Science and Technology Support Program (No. BE2013452)

  11. Cold rearing improves cold-flight performance in Drosophila via changes in wing morphology.

    PubMed

    Frazier, Melanie R; Harrison, Jon F; Kirkton, Scott D; Roberts, Stephen P

    2008-07-01

    We use a factorial experimental design to test whether rearing at colder temperatures shifts the lower thermal envelope for flight of Drosophila melanogaster Meigen to colder temperatures. D. melanogaster that developed in colder temperatures (15 degrees C) had a significant flight advantage in cold air compared to flies that developed in warmer temperatures (28 degrees C). At 14 degrees C, cold-reared flies failed to perform a take-off flight approximately 47% of the time whereas warm-reared flies failed approximately 94% of the time. At 18 degrees C, cold- and warm-reared flies performed equally well. We also compared several traits in cold- and warm-developing flies to determine if cold-developing flies had better flight performance at cold temperatures due to changes in body mass, wing length, wing loading, relative flight muscle mass or wing-beat frequency. The improved ability to fly at low temperatures was associated with a dramatic increase in wing area and an increase in wing length (after controlling for wing area). Flies that developed at 15 degrees C had approximately 25% more wing area than similarly sized flies that developed at 28 degrees C. Cold-reared flies had slower wing-beat frequencies than similarly sized flies from warmer developmental environments, whereas other traits did not vary with developmental temperature. These results demonstrate that developmental plasticity in wing dimensions contributes to the improved flight performance of D. melanogaster at cold temperatures, and ultimately, may help D. melanogaster live in a wide range of thermal environments.

  12. Linear Aerospike SR-71 Experiment (LASRE) ground cold flow test

    NASA Technical Reports Server (NTRS)

    1998-01-01

    This photograph shows a ground cold flow test of the linear aerospike rocket engine mounted on the rear fuselage of an SR-71. The LASRE experiment was designed to provide in-flight data to help Lockheed Martin evaluate the aerodynamic characteristics and the handling of the SR-71 linear aerospike experiment configuration. The goal of the project was to provide in-flight data to help Lockheed Martin validate the computational predictive tools it was using to determine the aerodynamic performance of a future reusable launch vehicle. The joint NASA, Rocketdyne (now part of Boeing), and Lockheed Martin Linear Aerospike SR-71 Experiment (LASRE) completed seven initial research flights at Dryden Flight Research Center. Two initial flights were used to determine the aerodynamic characteristics of the LASRE apparatus (pod) on the back of the SR-71. Five later flights focused on the experiment itself. Two were used to cycle gaseous helium and liquid nitrogen through the experiment to check its plumbing system for leaks and to test engine operational characteristics. During the other three flights, liquid oxygen was cycled through the engine. Two engine hot-firings were also completed on the ground. A final hot-fire test flight was canceled because of liquid oxygen leaks in the test apparatus. The LASRE experiment itself was a 20-percent-scale, half-span model of a lifting body shape (X-33) without the fins. It was rotated 90 degrees and equipped with eight thrust cells of an aerospike engine and was mounted on a housing known as the 'canoe,' which contained the gaseous hydrogen, helium, and instrumentation gear. The model, engine, and canoe together were called a 'pod.' The experiment focused on determining how a reusable launch vehicle's engine flume would affect the aerodynamics of its lifting-body shape at specific altitudes and speeds. The interaction of the aerodynamic flow with the engine plume could create drag; design refinements looked at minimizing this

  13. Improvement of cold resistance and performance of broilers by acute cold exposure during late embryogenesis.

    PubMed

    Shinder, D; Ruzal, M; Giloh, M; Druyan, S; Piestun, Y; Yahav, S

    2011-03-01

    The aim of this study was to fine-tune previous acute cold exposure treatments of broiler embryos during late embryogenesis to improve lifelong cold resistance and performance. Six hundred Cobb hatching eggs were incubated under standard conditions and then exposed to 3 treatments: control; cold treatment in which embryos were exposed to 15°C for 30 min on d 18 and 19 of incubation (30 × 2); and cold treatment similar to 30 × 2 but with 60-min exposures (60 × 2). Egg shell temperature (T(egg)) and heart rate (HR) were monitored pre- and posttreatment. Upon hatching, hatchability, body weight, and body temperature were recorded. From 14 to 35 d of age, three quarters of the chickens in each treatment were raised under ascites-inducing conditions (AIC) and the remaining birds were raised under standard brooding conditions (SBC). The T(egg) and HR decreased significantly in response to increased exposure time on d 18 of incubation. On d 19 of incubation, before the second cold exposure, the 30 × 2 group showed greater T(egg) and HR than the controls, and during the second exposure they maintained these parameters better than the 60 × 2 embryos. No treatment effect on hatchability was observed. At 35 d of age ascites incidence among 30 × 2 chickens under AIC was significantly less than that among the controls (P < 0.01), and body weight of these chickens under either SBC or AIC was significantly higher than that of the controls. Under SBC relative breast muscle weight was significantly higher in 60 × 2 chickens, whereas the relative heart weight was higher in both cold-treated groups than in the controls. It can be concluded that repeated short acute cold exposures during late embryogenesis significantly reduced ascites incidence and improved growth rate under either SBC or AIC. These results may be related to a prenatal epigenetic adaptation of the thermoregulatory and cardiovascular systems to low ambient temperature.

  14. Analysis of screeching in a cold flow jet experiment

    NASA Technical Reports Server (NTRS)

    Wang, M. E.; Slone, R. M., Jr.; Robertson, J. E.; Keefe, L.

    1975-01-01

    The screech phenomenon observed in a one-sixtieth scale model space shuttle test of the solid rocket booster exhaust flow noise has been investigated. A critical review is given of the cold flow test data representative of Space Shuttle launch configurations to define those parameters which contribute to screech generation. An acoustic feedback mechanism is found to be responsible for the generation of screech. A simple equation which permits prediction of screech frequency in terms of basic testing parameters such as the jet exhaust Mach number and the separating distance from nozzle exit to the surface of model launch pad is presented and is found in good agreement with the test data. Finally, techniques are recommended to eliminate or reduce the screech.

  15. Effects of a traditional herbal medicine on peripheral blood flow in women experiencing peripheral coldness: a randomized controlled trial.

    PubMed

    Nishida, Shinji; Eguchi, Eri; Ohira, Tetsuya; Kitamura, Akihiko; Kato, Yukiko Hakariya; Hagihara, Keisuke; Iso, Hiroyasu

    2015-04-02

    In Japan, a traditional herbal medicine, Tokishigyakukagoshuyushokyoto (TJ-38), is often used for the treatment of peripheral coldness, which is a common complaint among Japanese women. However, the effects of this herbal medicine have yet to be examined in a randomized controlled trial. In the current study, the effect of TJ-38 on the peripheral blood flow in women experiencing peripheral coldness was investigated using a parallel-group randomized controlled trial. Fifty-eight women aged 23 to 79 years with peripheral coldness were randomly divided into the intervention or control group. They were examined using cold bathing tests, physical examinations, and questionnaires in January 2010 for the baseline and in March 2010 for the follow-up, and January 2011 and March 2011, respectively. At the baseline, there were no differences in clinical characteristics between the two groups. In the intervention group, peripheral coldness improved after the intervention term; however, it persisted in the control group. Mean values of percentage recovery of the peripheral blood flow after cold bathing tests were 17.2% and -28.2% for the intervention and control groups, respectively (p = 0.007), and the proportions for percentage recovery of >50% were 32% and 0%, respectively (p = 0.0007). Mean values of percent recovery of skin temperature did not differ between the two groups. The present clinical trial supports that a traditional herbal medicine relieves peripheral coldness in women probably through the improvement of peripheral blood flow.

  16. Cold drink ingestion improves exercise endurance capacity in the heat.

    PubMed

    Lee, Jason K W; Shirreffs, Susan M; Maughan, Ronald J

    2008-09-01

    To investigate the effect of drink temperature on cycling capacity in the heat. On two separate trials, eight males cycled at 66 +/- 2% VO2peak (mean +/- SD) to exhaustion in hot (35.0 +/- 0.2 degrees C) and humid (60 +/- 1%) environments. Participants ingested three 300-mL aliquots of either a cold (4 degrees C) or a warm (37 degrees C) drink during 30 min of seated rest before exercise and 100 mL of the same drink every 10 min during exercise. Rectal and skin temperatures, heart rate, and sweat rate were recorded. Ratings of thermal sensation and perceived exertion were assessed. Exercise time was longer (P < 0.001) with the cold drink (63.8 +/- 4.3 min) than with the warm drink (52.0 +/- 4.1 min). Rectal temperature fell by 0.5 +/- 0.1 degrees C (P < 0.001) at the end of the resting period after ingestion of the cold drinks. There was no effect of drink temperature on mean skin temperature at rest (P = 0.870), but mean skin temperature was lower from 20 min during exercise with ingestion of the cold drink than with the warm drink (P < 0.05). Heart rate was lower before exercise and for the first 35 min of exercise with ingestion of the cold drink than with the warm drink (P < 0.05). Drink temperature influenced sweat rate (1.22 +/- 0.34 and 1.40 +/- 0.41 L x h(-1) for the cold and the warm drink, respectively; P < 0.05). Ratings of thermal sensation and perceived exertion (P < 0.01) during exercise were lower when the cold drink was ingested. Compared with a drink at 37 degrees C, the ingestion of a cold drink before and during exercise in the heat reduced physiological strain (reduced heat accumulation) during exercise, leading to an improved endurance capacity (23 +/- 6%).

  17. Facility for cold flow testing of solid rocket motor models

    NASA Astrophysics Data System (ADS)

    Bacchus, D. L.; Hill, O. E.; Whitesides, R. Harold

    1992-02-01

    A new cold flow test facility was designed and constructed at NASA Marshall Space Flight Center for the purpose of characterizing the flow field in the port and nozzle of solid propellant rocket motors (SRM's). A National Advisory Committee was established to include representatives from industry, government agencies, and universities to guide the establishment of design and instrumentation requirements for the new facility. This facility design includes the basic components of air storage tanks, heater, submicron filter, quiet control valve, venturi, model inlet plenum chamber, solid rocket motor (SRM) model, exhaust diffuser, and exhaust silencer. The facility was designed to accommodate a wide range of motor types and sizes from small tactical motors to large space launch boosters. This facility has the unique capability of testing ten percent scale models of large boosters such as the new Advanced Solid Rocket Motor (ASRM), at full scale motor Reynolds numbers. Previous investigators have established the validity of studying basic features of solid rocket motor development programs include the acquisition of data to (1) directly evaluate and optimize the design configuration of the propellant grain, insulation, and nozzle; and (2) provide data for validation of the computational fluid dynamics, (CFD), analysis codes and the performance analysis codes. A facility checkout model was designed, constructed, and utilized to evaluate the performance characteristics of the new facility. This model consists of a cylindrical chamber and converging/diverging nozzle with appropriate manifolding to connect it to the facility air supply. It was designed using chamber and nozzle dimensions to simulate the flow in a 10 percent scale model of the ASRM. The checkout model was recently tested over the entire range of facility flow conditions which include flow rates from 9.07 to 145 kg/sec (20 to 320 Ibm/sec) and supply pressure from 5.17 x 10 exp 5 to 8.27 x 10 exp 6 Pa. The

  18. Modelling capillary hysteresis effects on preferential flow through melting and cold layered snowpacks

    NASA Astrophysics Data System (ADS)

    Leroux, Nicolas R.; Pomeroy, John W.

    2017-09-01

    Accurate estimation of the amount and timing of water flux through melting snowpacks is important for runoff prediction in cold regions. Most existing snowmelt models only account for one-dimensional matrix flow and neglect to simulate the formation of preferential flow paths. Consideration of lateral and preferential flows has proven critical to improve the performance of soil and groundwater porous media flow models. A two-dimensional physically-based snowpack model that simulates snowmelt, refreezing of meltwater, heat and water flows, and preferential flow paths is presented. The model assumes thermal equilibrium between solid and liquid phases and uses recent snow physics advances to estimate snowpack hydraulic and thermal properties. For the first time, capillary hysteresis is accounted in a snowmelt model. A finite volume method is applied to solve for the 2D coupled heat and mass transfer equations. The model with capillary hysteresis provided better simulations of water suction at the wet to dry snow interface in a wetting snow sample than did a model that only accounted for the boundary drying curve. Capillary hysteresis also improved simulations of preferential flow path dynamics and the snowpack discharge hydrograph. Simulating preferential flow in a subfreezing snowpack allowed the model to generate ice layers, and increased the vertical exchange of energy, thus modelling a faster warming of the snowpack than would be possible without preferential flow. The model is thus capable of simulating many attributes of heterogeneous natural melting snowpacks. These features not only qualitatively improve water flow simulations, but improve the understanding of snowmelt flow processes for both level and sloping terrain, and illuminate how uncertainty in snowmelt-derived runoff calculations might be reduced through the inclusion of more realistic preferential flow through snowpacks.

  19. Galaxy bimodality due to cold flows and shock heating

    NASA Astrophysics Data System (ADS)

    Dekel, Avishai; Birnboim, Yuval

    2006-05-01

    We address the origin of the robust bimodality observed in galaxy properties about a characteristic stellar mass ~3 × 1010Msolar. Less massive galaxies tend to be ungrouped blue star forming discs, while more massive galaxies are typically grouped red old-star spheroids. Colour-magnitude data show a gap between the red and blue sequences, extremely red luminous galaxies already at z~ 1, a truncation of today's blue sequence above L*, and massive starbursts at z~ 2-4. We propose that these features are driven by the thermal properties of the inflowing gas and their interplay with the clustering and feedback processes, all functions of the dark matter halo mass and associated with a similar characteristic scale. In haloes below a critical shock-heating mass Mshock<~ 1012Msolar, discs are built by cold streams, not heated by a virial shock, yielding efficient early star formation. It is regulated by supernova feedback into a long sequence of bursts in blue galaxies constrained to a `fundamental line'. Cold streams penetrating through hot media in M>=Mshock haloes preferentially at z>= 2 lead to massive starbursts in L > L* galaxies. At z < 2, in M > Mshock haloes hosting groups, the gas is heated by a virial shock, and being dilute it becomes vulnerable to feedback from energetic sources such as active galactic nuclei. This shuts off gas supply and prevents further star formation, leading by passive evolution to `red-and-dead' massive spheroids starting at z~ 1. A minimum in feedback efficiency near Mshock explains the observed minimum in M/L and the qualitative features of the star formation history. The cold flows provide a hint for solving the angular momentum problem. When these processes are incorporated in simulations they recover the main bimodality features and solve other open puzzles.

  20. Cold-Induced Perturbation of Cutaneous Blood Flow in the Rat Tail: A model of Nonfreezing Cold Injury

    DTIC Science & Technology

    1994-01-01

    initially by several days of reduced blood flow and thermal sensitivity, folowed in a week by a hyperemia stage, and later by enhanced vascular and thermal ...evidenced by reduction in peripheral blood * J .flow and lack of sensation, followed by a hyperemic stage, and then followed by intensified thermal ...change in tail blood flow or temperature. The longer cold sessions involved exposure of only the tail. wit.h minimal direct thermal stress to the whole

  1. Insights into Cold Water Injection Stimulation Effects through Analytical Solutions to Flow and Heat Transport

    SciTech Connect

    M.A. Plummer

    2013-09-01

    Wells in traditional hydrothermal reservoirs are used to extract heat and to dispose of cooled water. In the first case, high productivity (the ratio of production flow rate to the pressure differential required to produce that rate) to is preferred in order to maximize power generation, while minimizing the parasitic energy loss of pumping. In the second case, high injectivity (the ratio of injection flow rate to the pressure differential required to produce that rate) is preferred, in order to reduce pumping costs. In order to improve productivity or injectivity, cold water is sometimes injected into the reservoir in an attempt to cool and contract the surrounding rock matrix and thereby induce dilation and/or extension of existing fractures or to generate new fractures. Though the increases in permeability associated with these changes are likely localized, by improving connectivity to more extensive high-permeability fractures they can at least temporarily provide substantially improved productivity or injectivity.

  2. Cold flow properties of biodiesel: A guide to getting an accurate analysis

    USDA-ARS?s Scientific Manuscript database

    Biodiesel has several advantages compared to conventional diesel fuel (petrodiesel). Nevertheless, biodiesel has poor cold flow properties that may restrict its use in moderate climates. It is essential that the cold flow properties of biodiesel and its blends with petrodiesel be measured as accurat...

  3. Improving emergency department patient flow

    PubMed Central

    Jarvis, Paul Richard Edwin

    2016-01-01

    Emergency departments (ED) face significant challenges in delivering high quality and timely patient care on an ever-present background of increasing patient numbers and limited hospital resources. A mismatch between patient demand and the ED’s capacity to deliver care often leads to poor patient flow and departmental crowding. These are associated with reduction in the quality of the care delivered and poor patient outcomes. A literature review was performed to identify evidence-based strategies to reduce the amount of time patients spend in the ED in order to improve patient flow and reduce crowding in the ED. The use of doctor triage, rapid assessment, streaming and the co-location of a primary care clinician in the ED have all been shown to improve patient flow. In addition, when used effectively point of care testing has been shown to reduce patient time in the ED. Patient flow and departmental crowding can be improved by implementing new patterns of working and introducing new technologies such as point of care testing in the ED. PMID:27752619

  4. Improving emergency department patient flow.

    PubMed

    Jarvis, Paul Richard Edwin

    2016-06-01

    Emergency departments (ED) face significant challenges in delivering high quality and timely patient care on an ever-present background of increasing patient numbers and limited hospital resources. A mismatch between patient demand and the ED's capacity to deliver care often leads to poor patient flow and departmental crowding. These are associated with reduction in the quality of the care delivered and poor patient outcomes. A literature review was performed to identify evidence-based strategies to reduce the amount of time patients spend in the ED in order to improve patient flow and reduce crowding in the ED. The use of doctor triage, rapid assessment, streaming and the co-location of a primary care clinician in the ED have all been shown to improve patient flow. In addition, when used effectively point of care testing has been shown to reduce patient time in the ED. Patient flow and departmental crowding can be improved by implementing new patterns of working and introducing new technologies such as point of care testing in the ED.

  5. Improving Efficiency of Aluminium Sacrificial Anode Using Cold Work Process

    NASA Astrophysics Data System (ADS)

    Asmara, Y. P.; Siregar, J. P.; Tezara, C.; Ann, Chang Tai

    2016-02-01

    Aluminium is one of the preferred materials to be used as sacrificial anode for carbon steel protection. The efficiency of these can be low due to the formation of oxide layer which passivate the anodes. Currently, to improve its efficiency, there are efforts using a new technique called surface modifications. The objective of this research is to study corrosion mechanism of aluminium sacrificial anode which has been processed by cold work. The cold works are applied by reducing the thickness of aluminium sacrificial anodes at 20% and 40% of thickness reduction. The cathodic protection experiments were performed by immersion of aluminium connected to carbon steel cylinder in 3% NaCl solutions. Visual inspections using SEM had been conducted during the experiments and corrosion rate data were taken in every week for 8 weeks of immersion time. Corrosion rate data were measured using weight loss and linear polarization technique (LPR). From the results, it is observed that cold worked aluminium sacrificial anode have a better corrosion performance. It shows higher corrosion rate and lower corrosion potential. The anodes also provided a long functional for sacrificial anode before it stop working. From SEM investigation, it is shown that cold works have changed the microstructure of anodes which is suspected in increasing corrosion rate and cause de-passivate of the surface anodes.

  6. Viscous computations of cold air/air flow around scramjet nozzle afterbody

    NASA Technical Reports Server (NTRS)

    Baysal, Oktay; Engelund, Walter C.

    1991-01-01

    The flow field in and around the nozzle afterbody section of a hypersonic vehicle was computationally simulated. The compressible, Reynolds averaged, Navier Stokes equations were solved by an implicit, finite volume, characteristic based method. The computational grids were adapted to the flow as the solutions were developing in order to improve the accuracy. The exhaust gases were assumed to be cold. The computational results were obtained for the two dimensional longitudinal plane located at the half span of the internal portion of the nozzle for over expanded and under expanded conditions. Another set of results were obtained, where the three dimensional simulations were performed for a half span nozzle. The surface pressures were successfully compared with the data obtained from the wind tunnel tests. The results help in understanding this complex flow field and, in turn, should help the design of the nozzle afterbody section.

  7. Energy efficiency improvement of electric drive of cold pilgering mill

    NASA Astrophysics Data System (ADS)

    Sychev, D. A.; Savosteenko, N. V.; Gryzlov, A. A.

    2017-02-01

    Different ways to improve the energy efficiency of electric drives of cold pilgering mill are considered. Mathematical modeling methods represent studies according to which it is possible to evaluate quantitatively the energy savings. For example, cold pilgering mill 450 shows the mean square of the armature current of the main drive motor related to critical frequency of the speed loop. The possibility of energy saving by previous field weakening of the motor before the operating cycle of rolling is considered. The optimal energy saving points of supply and termination of the pulse are determined by the field weakening. The correlation of the parameters of the dynamic units and the change of the electric drive work schedule provides the greatest loss reduction in the main drive of the cold pilgering mill stand based on the conditions. Activities aimed at improving energy efficiency of electric drives of mills of this group are reviewed, which reduces the electric energy consumption for the cycle rolling by 20-25 %.

  8. Supersonic turbulent flows and the fragmentation of a cold medium

    NASA Astrophysics Data System (ADS)

    Padoan, Paolo

    1995-11-01

    The role played by velocity fields in the fragmentation of a cold medium and in the formation of protostars is studied. The velocity field is modelled with a compressible turbulent flow. A supersonic turbulent velocity field can fragment the medium into clumps of mass smaller than a local Jeans mass, and therefore stabilize the medium against the formation of protostars. Based on this idea, the protostar formation efficiency and the protostar mass distribution are determined as functions of the following ambient parameters: average density n_0, average temperature T_0, rms turbulent velocity sigma_upsilon,0 (or its Mach number M_t), and post-shock cooling time (e.g. chemistry). The main results are as follows. (i) The protostar's mass distribution and its dependence on the ambient parameters are quantified. (ii) The characteristic protostar mass is M_J,cl~n^-1/20T^20sigma^-1upsilon,0. (iii) The protostar formation efficiency e grows with increasing mean density and mean temperature, decreasing velocity dispersion on a given scale and increasing post-shock cooling time (e.g. lower metallicity): e~n^[(3/2)(beta-1)]0T^beta-10sigma^-5(beta-1)upsilon,0L^3(beta-1)0, where beta<~1 is the exponent of the clump mass distribution. (iv) The efficiency is quite sensitive to the ambient parameters and therefore to the dynamical evolution of the star-forming system.

  9. Combination of ethylene polymer, normal paraffinic wax and nitrogen containing compound (stabilized, if desired, with one or more compatibility additives) to improve cold flow properties of distillate fuel oils

    SciTech Connect

    Dooley, M.; Feldman, N.; Ryer, J.

    1980-07-01

    A description is given of a wax-containing petroleum fuel oil comprising a major proportion of a distillate oil boiling in the range of 120/sup 0/ to 42 5/sup 0/ C, which fuel oil has been improved in its low temperature flow properties, containing in the range of about 0.001 to 2.5 wt. %, based on the weight of the total composition, of a flow improving combination of: (A) one part by weight of an oil-soluble ethylene backbone distillate flow improving polymer having a number average molecular weight in the range of about 500 to 50,000; (B) 0.1 to 30 parts by weight of wax comprising principally n-paraffins having from 20 to 60 carbons; and (C) 0.01 to 10 parts weight of an oil-soluble nitrogen compound containing a total of about 30 to 300 carbon atoms and having at least one straight chain alkyl segment of 8 to 40 carbons, and selected from the class consisting of amine salts and/or amides of hydrocarbyl carboxylic acids or anhydrides having 1 to 4 carbonyl groups.

  10. Improved trapping and transport of cold atoms for magnetic microscopy

    NASA Astrophysics Data System (ADS)

    Gadge, Amruta; James, T.; Li, X.; Lu, Bo; Garridogonzalez, N.; Finke, A.; Mellor, C.; Fromhold, M.; Koller, C.; Orucevic, F.; Kruger, Peter

    2016-05-01

    Using cold atoms, a very sensitive and high resolution magnetic and electric field sensor can be realised. Ultra-close trapping of atoms would improve the resolution of cold-atom based surface probes. The limitation on the trapping distance arises from strongly distance-dependent effects such as Casimir force, Johnson noise etc. We are constructing an experimental system to trap atoms at surface separations of less than a micron. We will demonstrate the possibility of using special surfaces such as silicon nitride membranes and graphene for sub-micron trapping. We have designed a 10-layer printed circuit board, which can magnetically trap the cold atom cloud and transport it precisely to a desired location. This gives us the ability to study multiple samples within the same vacuum environment. In order to achieve higher atom number in the initial trapping stages, we use a dual-color MOT technique for Rb-87 atoms. Using this technique we achieve a significant increase in atom number and decrease in temperature. In this talk, I will present the results of the dual color MOT. I will also report on results related to magnetic transport and sub-micron trapping of atoms.

  11. COLD-PCR: improving the sensitivity of molecular diagnostics assays

    PubMed Central

    Milbury, Coren A; Li, Jin; Liu, Pingfang; Makrigiorgos, G Mike

    2011-01-01

    The detection of low-abundance DNA variants or mutations is of particular interest to medical diagnostics, individualized patient treatment and cancer prognosis; however, detection sensitivity for low-abundance variants is a pronounced limitation of most currently available molecular assays. We have recently developed coamplification at lower denaturation temperature-PCR (COLD-PCR) to resolve this limitation. This novel form of PCR selectively amplifies low-abundance DNA variants from mixtures of wild-type and mutant-containing (or variant-containing) sequences, irrespective of the mutation type or position on the amplicon, by using a critical denaturation temperature. The use of a lower denaturation temperature in COLD-PCR results in selective denaturation of amplicons with mutation-containing molecules within wild-type mutant heteroduplexes or with a lower melting temperature. COLD-PCR can be used in lieu of conventional PCR in several molecular applications, thus enriching the mutant fraction and improving the sensitivity of downstream mutation detection by up to 100-fold. PMID:21405967

  12. Thermal face protection delays finger cooling and improves thermal comfort during cold air exposure.

    PubMed

    O'Brien, Catherine; Castellani, John W; Sawka, Michael N

    2011-12-01

    When people dress for cold weather, the face often remains exposed. Facial cooling can decrease finger blood flow, reducing finger temperature (T (f)). This study examined whether thermal face protection limits finger cooling and thereby improves thermal comfort and manual dexterity during prolonged cold exposure. T (f) was measured in ten volunteers dressed in cold-weather clothing as they stood for 60 min facing the wind (-15°C, 3 m s(-1)), once while wearing a balaclava and goggles (BAL), and once with the balaclava pulled down and without goggles (CON). Subjects removed mitts, wearing only thin gloves to perform Purdue Pegboard (PP) tests at 15 and 50 min, and Minnesota Rate of Manipulation (MRM) tests at 30 and 55 min. Subjects rated their thermal sensation and comfort just before the dexterity tests. T (f) decreased (p < 0.05 for time × trial interaction) by 15 min of cold exposure during CON (33.6 ± 1.4-28.7 ± 2.0°C), but not during BAL (33.2 ± 1.4-30.6 ± 3.2°C); and after 30 min T (f) remained warmer during BAL (23.3 ± 5.9°C) than CON (19.2 ± 3.5); however, by 50 min, T (f) was no different between trials (14.1 ± 2.7°C). Performance on PP fell (p < 0.05) by 25% after 50 min in both trials; MRM performance was not altered by cold on either trial. Subjects felt colder (p < 0.05) and more uncomfortable (p < 0.05) during CON, compared to BAL. Thermal face protection was effective for maintaining warmer T (f) and thermal comfort during cold exposure; however, local cooling of the hands during manual dexterity tests reduced this physiological advantage, and performance was not improved.

  13. Simulation and analysis on the flow field of the low temperature mini-type cold store

    NASA Astrophysics Data System (ADS)

    Hao, X. H.; Ju, Y. L.

    2011-07-01

    The understanding of the flow field inside the cold store is very important to food storage at low temperatures. In this paper, the CFD simulation on the flow field for low temperature cold store with air forced supply mode is presented. The turbulence flow of three-dimensional steady incompressible viscous fluid is analyzed using finite volume method and standard K-ɛ two-equation. The temperature and velocity fields of this cold store are simulated, analyzed and compared. The simulation results show that the velocity and temperature fields are evidently influenced by the cross section from the ground, and the optimal cross section is also given in this paper.

  14. Large Eddy Simulation of Supersonic Cold Flow in Ramp-Cavity Combustor with Fuel Injector

    NASA Astrophysics Data System (ADS)

    Ghiasi, Zia; Li, Dongru; Komperda, Jonathan; Mashayek, Farzad

    2015-11-01

    Numerical simulation of supersonic flows is technologically important in efficient design and development of high-speed propulsion systems. The supersonic flow within the combustion chamber of scramjet is a prime example of multi-scale and multi-physics flow and is generally accompanied by concurrent presence of shock waves and turbulence. Developing a robust numerical method for such simulations leads to various technical challenges due to the presence of complex geometries, shocks, and turbulence, and normally requires massively parallel computation. In the present work, we employ the Discontinuous Spectral Element Method (DSEM) for high-fidelity simulation of supersonic and turbulent flows. The numerical code features an entropy-based artificial viscosity method for capturing shock waves and standard Smagorinsky-Lilly model for turbulence modeling. Two different turbulence sensors are also developed to improve the turbulent viscosity at the shocked areas and the inlet boundary layer. A supersonic cold flow within a ramp-cavity flame holder featuring a round fuel injector at the ramped side of the cavity is simulated. Results are provided and the physics of the flow is studied.

  15. Cold Flow Properties of Biodiesel by Automatic and Manual Analysis Methods

    USDA-ARS?s Scientific Manuscript database

    Biodiesel from most common feedstocks has inferior cold flow properties compared to conventional diesel fuel. Blends with as little as 10 vol% biodiesel content typically have significantly higher cloud point (CP), pour point (PP) and cold filter plugging point (CFPP) than No. 2 grade diesel fuel (...

  16. Perflubron emulsion prevents PMN activation and improves myocardial functional recovery after cold ischemia and reperfusion.

    PubMed

    Gale, Stephen C; Gorman, Grace D; Copeland, Jack G; McDonagh, Paul F

    2007-03-01

    In cardiopulmonary bypass, extracorporeal circulation activates neutrophils, which contribute to ischemia reperfusion injury and postoperative myocardial dysfunction. Perfluorocarbons (PFCs) are compounds that dissolve oxygen and have anti-inflammatory and neutrophil-stabilizing properties. We hypothesized that perflubron emulsion (PFE), a PFC, would attenuate neutrophil activation during simulated extracorporeal circulation (SECC) and would preserve myocardial functional recovery during reperfusion after cold ischemia. In a SECC, diluted blood was circulated for 120 min and subsequently used to reperfuse isolated rat hearts after 2 h of cold (12 degrees C) ischemia. Three groups were studied: noncirculated control; SECC/no additive; and SECC/PFE added. In control and SECC/no additive groups, whole blood was diluted 1:1 with plasmalyte. SECC/PFE blood was diluted 1:1 with plasmalyte and PFE (0.075 mL/mL diluted whole blood). Blood counts and neutrophil activation experiments were performed before and after 120 min of SECC. Reperfusion was accomplished using a modified Langendorff preparation. Left ventricular developed pressure, dP/dt, and coronary flow were measured at 10, 15, and 20 min of reperfusion. After 120 min SECC, neutrophil activation was significantly reduced in the SECC/PFE group compared to the SECC/no additive group (38.1 +/- 2.3% versus 51.7 +/- 1.0%, P < 0.05). Compared to cold ischemic hearts reperfused with fresh, non-recirculated blood, left ventricular developed pressure and dP/dt were significantly impaired in the cold ischemic hearts reperfused with SECC/no additive blood (P < 0.05). In contrast, myocardial functional recovery was not impaired in the hearts reperfused with SECC/PFE blood. SECC-induced neutrophil activation was attenuated with Perflubron treatment. In addition, the progressive impairment in myocardial functional recovery after cold ischemia was significantly improved with treatment. PFE has clinical potential to limit

  17. Temperature-Controlled Continuous Cold Flow Device after Total Knee Arthroplasty: A Randomized Controlled Trial Study.

    PubMed

    Ruffilli, Alberto; Castagnini, Francesco; Traina, Francesco; Corneti, Isabella; Fenga, Domenico; Giannini, Sandro; Faldini, Cesare

    2016-11-30

    Total knee arthroplasty (TKA) is a widely accepted and successful procedure for end-stage arthritis. Nevertheless, fast-track may be compromised by many factors, such as pain, edema, and blood loss. Cryotherapy has been advocated as a safe and effective strategy to improve the postoperative results, acting on pain, edema, and blood loss. This study is a prospective randomized controlled study, involving 50 patients after primary TKA. A power analysis was performed preoperatively. Twenty-four patients were addressed to a postoperative treatment with a continuous cold flow device (Hilotherm, Hilotherm GmbH, Germany). Twenty-six patients represented the control group, treated with crushed ice packs. All the patients shared the same analgesic strategy and the same rehabilitation protocol. Pain, analgesic consumption, active knee range of motion, drain output, transfusion requirement, and total blood loss were evaluated at different follow-ups (postoperative first, third, and seventh days). The two groups were homogenous for preoperative and intraoperative features. The groups showed no statistically significant differences in all the evaluated parameters. A modest reduction of knee volume was evident after 7 days from surgery (trend). No differences in blood loss were noticed. Continuous cold flow device in the acute postoperative setting after TKA did not show superiority in reducing edema, pain, and blood loss, compared with traditional icing regimen. Thus, due to the costs, it should be reserved to selected cases.

  18. The discovery of large amounts of cold, X-ray absorbing matter in cooling flows

    NASA Technical Reports Server (NTRS)

    White, D. A.; Fabian, A. C.; Johnstone, R. M.; Mushotzky, R. F.; Arnaud, K. A.

    1991-01-01

    The discovery of significant excess absorption in the X-ray spectra of 12 clusters of galaxies is reported. The spectra also require a cooling-flow component, which confirms the results of imaging studies of the clusters showing the strongly peaked emission characteristic of cooling flows. The total mass of absorbing gas is determined on the assumption that it is distributed through the cooling flow region and has cosmic abundance. It is shown that the gas is most likely in the form of small cold clouds. The excess absorption is interpreted as being due to photoelectric absorption in cold gas clouds distributed through the cooling flows.

  19. The discovery of large amounts of cold, X-ray absorbing matter in cooling flows

    NASA Technical Reports Server (NTRS)

    White, D. A.; Fabian, A. C.; Johnstone, R. M.; Mushotzky, R. F.; Arnaud, K. A.

    1991-01-01

    The discovery of significant excess absorption in the X-ray spectra of 12 clusters of galaxies is reported. The spectra also require a cooling-flow component, which confirms the results of imaging studies of the clusters showing the strongly peaked emission characteristic of cooling flows. The total mass of absorbing gas is determined on the assumption that it is distributed through the cooling flow region and has cosmic abundance. It is shown that the gas is most likely in the form of small cold clouds. The excess absorption is interpreted as being due to photoelectric absorption in cold gas clouds distributed through the cooling flows.

  20. Cold air drainage flows subsidize montane valley ecosystem productivity

    Treesearch

    Kimberly A. Novick; Andrew C. Oishi; Chelcy Ford Miniat

    2016-01-01

    In mountainous areas, cold air drainage from high to low elevations has pronounced effects on local temperature, which is a critical driver of many ecosystem processes, including carbon uptake and storage. Here, we leverage new approaches for interpreting ecosystem carbon flux observations in complex terrain to quantify the links between macro-climate...

  1. Changes of coronary blood flow in vasospastic angina under cold stimulation by transthoracic Doppler echocardiography.

    PubMed

    Park, Seong Mi; Shim, Wan Joo; Ahn, Jung Cheon; Lim, Do Sun; Kim, Young Hoon; Ro, Young Moo

    2005-04-01

    This study was done to evaluate changes of microvascular function under cold stimulation by measuring coronary flow velocities (CFVs) in vasospastic angina (VA) patients using transthoracic Doppler echocardiography (TTDE). 14 patients with VA and 15 healthy controls were included. CFVs were measured at the distal left anterior descending coronary artery by TTDE at baseline and under cold stimulation. Hyperemia was induced by intravenous adenosine infusion (140 microg/kg/min). At baseline, CFVs and coronary flow reserve (CFR) were not different between controls and VA patients. Under cold stimulation, the degree of increment of CFV with adenosine was lower in VA patients than in controls. Comparing baseline with cold stimulation, coronary flow reserve (CFR) increased (3.1+/-0.7 to 3.8 +/-1.0, p=0.06) in controls. In contrast, in VA patients, CFR was decreased (2.8 +/-0.9 to 2.6 +/-0.7, p=0.05) and coronary vascular resistance index markedly increased (0.35 to 0.43, p=0.01). Throughout the study, no patient experienced chest pain or ECG changes. In VA patients, CFR was preserved at baseline, but coronary blood flow increase in response to cold stimulation was blunted and CFR was decreased. These findings suggest that endothelial dependent vasodilation is impaired at the coronary microvascular and the epicardial artery level in VA under cold stimulation.

  2. Solute transport modelling in a coupled water and heat flow system applied to cold regions hydrogeology

    NASA Astrophysics Data System (ADS)

    Frampton, Andrew; Destouni, Georgia

    2016-04-01

    In cold regions, flow in the unsaturated zone is highly dynamic with seasonal variability and changes in temperature, moisture, and heat and water fluxes, all of which affect ground freeze-thaw processes and influence transport of inert and reactive waterborne substances. In arctic permafrost environments, near-surface groundwater flow is further restricted to a relatively shallow and seasonally variable active layer, confined by perennially frozen ground below. The active layer is typically partially saturated with ice, liquid water and air, and is strongly dependent on seasonal temperature fluctuations, thermal forcing and infiltration patterns. Here there is a need for improved understanding of the mechanisms controlling subsurface solute transport in the partially saturated active layer zone. Studying solute transport in cold regions is relevant to improve the understanding of how natural and anthropogenic pollution may change as activities in arctic and sub-arctic regions increase. It is also particularly relevant for understanding how dissolved carbon is transported in coupled surface and subsurface hydrological systems under climate change, in order to better understand the permafrost-hydrological-carbon climate feedback. In this contribution subsurface solute transport under surface warming and degrading permafrost conditions is studied using a physically based model of coupled cryotic and hydrogeological flow processes combined with a particle tracking method. Changes in subsurface water flows and solute transport travel times are analysed for different modelled geological configurations during a 100-year warming period. Results show that for all simulated cases, the minimum and mean travel times increase non-linearly with warming irrespective of geological configuration and heterogeneity structure. The travel time changes are shown to depend on combined warming effects of increase in pathway length due to deepening of the active layer, reduced transport

  3. Cold Acclimation Improves Regrowth of Cryopreserved Apple Shoot Tips

    USDA-ARS?s Scientific Manuscript database

    Cryopreservation is important for preserving the genetic resources of apple germplasm in Kazakhstan, the center of origin for apples. In this study of five apple genotypes [Malus domestica Borkh. and Malus sieversii (Ledeb.) M. Roem] we determined cold hardiness and the effect of cold acclimation o...

  4. Proper planning improves flow drilling

    SciTech Connect

    Collins, G.J. )

    1994-10-01

    Underbalanced operations reduce formation damage, especially in horizontal wells where zones are exposed to mud for longer time periods. Benefits, risks, well control concerns, equipment and issues associated with these operations are addressed in this paper. Flow drilling raises many concerns, but little has been published on horizontal well control and flow drilling operations. This article covers planning considerations for flow drilling, but does not address horizontal ''overbalanced'' drilling because considerations and equipment are the same as in vertical overbalanced drilling and many references address that subject. The difference in well control between vertical and horizontal overbalanced drilling is fluid influx behavior and how that behavior affects kill operations.

  5. Numerical investigation of scale effect of various injection diameters on interaction in cold kerosene-fueled supersonic flow

    NASA Astrophysics Data System (ADS)

    Zhu, Lin; Qi, Yin-Yin; Liu, Wei-Lai; Xu, Bao-Jian; Ge, Jia-Ru; Xuan, Xiang-Chun; Jen, Tien-Chien

    2016-12-01

    The incident shock wave generally has a strong effect on the transversal injection field in cold kerosene-fueled supersonic flow, possibly due to its affecting the interaction between incoming flow and fuel through various operation conditions. This study is to address scale effect of various injection diameters on the interaction between incident shock wave and transversal cavity injection in a cold kerosene-fueled scramjet combustor. The injection diameters are separately specified as from 0.5 to 1.5 mm in 0.5 mm increments when other performance parameters, including the injection angle, velocity and pressure drop are all constant. A combined three dimensional Couple Level Set & Volume of Fluids (CLSVOF) approach with an improved K-H & R-T model is used to characterize penetration height, span expansion area, angle of shock wave and sauter mean diameter (SMD) distribution of the kerosene droplets with/without considering evaporation. Our results show that the injection orifice surely has a great scale effect on the transversal injection field in cold kerosene-fueled supersonic flows. Our findings show that the penetration depth, span angle and span expansion area of the transverse cavity jet are increased with the injection diameter, and that the kerosene droplets are more prone to breakup and atomization at the outlet of the combustor for the orifice diameter of 1.5 mm. The calculation predictions are compared against the reported experimental measurements and literatures with good qualitative agreement. The simulation results obtained in this study can provide the evidences for better understanding the underlying mechanism of kerosene atomization in cold supersonic flow and scramjet design improvement.

  6. Constitutive Description of Tensile Flow Behavior of Cold Flow-Formed AFNOR 15CDV6 Steel at Different Deformation Levels

    NASA Astrophysics Data System (ADS)

    Mondal, Chandan; Podder, Bikramjit; Ramesh Kumar, K.; Yadav, D. R.

    2014-10-01

    The influences of cold deformation on the room temperature tensile stress-strain behavior of a flow-formed AFNOR 15CDV6 steel have been evaluated in the deformation range of 74-86% at a nominal strain rate of 6.67 × 10-4 s-1. Constitutive description of the tensile plastic flow has been illustrated through a comparative description of widely used empirical relationships proposed by Hollomon, Ludwigson, Pickering and Voce. Both the Voce and Pickering relations adequately describe the tensile flow behavior of all the specimens. Although the standard Ludwigson relation does not fit the experimental data satisfactorily, the fitting ability improves dramatically when a modified relation with the negative deviation compensating parameter has been employed. Physical interpretation of the fitting parameters based on observed microstructural features of the materials is further attempted. The variations in Ludwigson ( n 2) and Voce ( K v) parameters match well with the trend in the development of delamination cracks due to internal stress fields. Such behavior is directly linked to the uniform elongation of the materials. The tensile work hardening behavior has been elucidated by the differential and modified Crussard-Jaoul methods. Such analyses in corroboration with microstructural characterization indicate the development of internal stress field during highly constrained material flow in a banded structure. The consequence of this phenomenon is manifested in the formation of severe delamination cracks that significantly affect the uniform elongation of the specimens. Furthermore, the Estrin-Mecking analysis of microstructural attributes to the work hardening behavior points out the dynamic recovery controlled deformation mechanism in 86% deformed specimen.

  7. An Investigation of Transonic Flow Fields Surrounding Hot and Cold Sonic Jets

    NASA Technical Reports Server (NTRS)

    Lee, George

    1961-01-01

    An investigation at free-stream Mach numbers of 0.90 t o 1.10 was made to determine (1) the jet boundaries and the flow fields around hot and cold jets, and (2) whether a cold-gas jet could adequately simulate the boundary and flow field of hot-gas jet. Schlieren photographs and static-pressure surveys were taken in the vacinity of a sonic jet which was operated over a range of jet pressure ratios of 1 to 6, specific heat ratios at the nozzle exit of 1.29 and 1.40, and jet temperatures up to 2600 R.

  8. Characterization of a cold flow non-axisymmetric supersonic ejector

    NASA Astrophysics Data System (ADS)

    Lineberry, David M.

    Experimental investigations of dual and single nozzle non-axisymmetric strut based supersonic ejectors were carried out. The strut nozzles transitioned from a round throat to a square exit with an expansion ratio of 4.6. The ejector system entrained secondary air from the lab and exhausted to the lab at atmospheric pressure. The ejectors were operated at equivalent mass flow rates at primary chamber pressure to back pressure ratios ranging from 6.8 to 61.2 for the single nozzle strut and 3.4 to 30.6 for the dual nozzle strut. Under these conditions both struts demonstrated operation in three distinct regimes: mixed, saturated supersonic and supersonic. Secondary flow choking was demonstrated for both struts at equivalent primary mass flow rates. The mixing length was determined by pressure recovery or equalization with the back pressure. This length remained relatively constant at approximately 20 nozzle hydraulic diameters for the primary mass flow rates in the mixed regime. At higher mass flow rates, the pressure recovery length increased and appeared to be strongly affected by the primary nozzle exit pressure. Surveys of duct exit stagnation pressure indicated poor mixing at high mass flow rates with a supersonic core existing through the mixing duct. Shadow graph images revealed a complex shock structure in the recovery region of the mixing duct. Classical analytical models for axisymmetric ejectors were used to investigate the effect of non-axisymmetric geometry. Preliminary CFD simulations were performed to investigate ejector mixing.

  9. Anthocyanin-rich Aronia melanocarpa extract improves body temperature maintenance in healthy women with a cold constitution.

    PubMed

    Sonoda, Keisuke; Aoi, Wataru; Iwata, Tomoaki; Li, Yanmei

    2013-01-01

    Specific anthocyanin-rich dietary factors have been shown to improve metabolic functions associated with thermogenesis in animal studies. Aronia melanocarpa, commonly known as wild chokeberry, contains a high level of anthocyanin that would be expected to maintain body temperature through thermogenesis. We here investigated the effects of Aronia melanocarpa extracts on body temperature and peripheral blood flow in healthy women with a cold constitution. A pre/post comparison trial was performed in 11 women with a cold constitution, who were taking Aronia melanocarpa extracts (150 mg/day) for 4 weeks. Physiological and biochemical parameters, along with psychological tests were examined. The subjects' body surface temperature was significantly higher in the post-trial than in the pre-trial. In psychological tests, factors related to cold were significantly improved by Aronia intake. On the other hand, peripheral blood flow was not affected by Aronia supplementation. Plasma noradrenalin level was significantly elevated by Aronia intake, and subjects with a higher level of 8-hydroxy-2'-deoxyguanosine in the pre-trial showed decreased levels in the post-trial. These data suggest that dietary Aronia melanocarpa extract improves the maintenance of body temperature in healthy women with a cold constitution, which may be mediated by noradrenalin and oxidative stress levels.

  10. SR-71 LASRE during in-flight cold flow test

    NASA Technical Reports Server (NTRS)

    1998-01-01

    This shot, from above and behind the SR-71 in flight, runs 11 seconds and shows the Aerospike engine and its fuel system being charged with gaseous helium and liquid nitrogen during one of two tests. The tests are to check for leaks and check the flow characteristics of cryogenic fuels to be used in the engine. The NASA/Lockheed Martin Linear Aerospike SR-71 Experiment (LASRE) concluded its flight operations phase at the NASA Dryden Flight Research Center, Edwards, California, in November 1998. The goal of this experiment was to provide in-flight data to help Lockheed Martin, Bethesda, Maryland, validate the computational predictive tools it was using to determine the aerodynamic performance of a future potential reusable launch vehicle. Information from the LASRE experiment will help Lockheed Martin maximize its design for a future potential reusable launch vehicle. It gave Lockheed an understanding of the performance of the lifting body and linear aerospike engine combination even before the X-33 Advanced Technology Demonstrator flies. LASRE was a small, half-span model of a lifting body with eight thrust cells of an aerospike engine. The experiment, mounted on the back of an SR-71 aircraft, operates like a kind of 'flying wind tunnel.' The experiment focused on determining how the engine plume of a reusable launch vehicle engine plume would affect the aerodynamics of its lifting body shape at specific altitudes and speeds reaching approximately 750 miles per hour. The interaction of the aerodynamic flow with the engine plume could create drag; design refinements look to minimize that interaction. During the flight research program, the aircraft completed seven research flights. Two initial flights were used to determine the aerodynamic characteristics of the LASRE apparatus on the back of the aircraft. The first of those two flights occurred October 31, 1997. The SR-71 took off at 8:31 a.m. PST. The aircraft flew for one hour and fifty minutes, reaching a

  11. SR-71 LASRE during in-flight cold flow test

    NASA Technical Reports Server (NTRS)

    1998-01-01

    This shot, from above and behind the SR-71 in flight, runs 11 seconds and shows the Aerospike engine and its fuel system being charged with gaseous helium and liquid nitrogen during one of two tests. The tests are to check for leaks and check the flow characteristics of cryogenic fuels to be used in the engine. The NASA/Lockheed Martin Linear Aerospike SR-71 Experiment (LASRE) concluded its flight operations phase at the NASA Dryden Flight Research Center, Edwards, California, in November 1998. The goal of this experiment was to provide in-flight data to help Lockheed Martin, Bethesda, Maryland, validate the computational predictive tools it was using to determine the aerodynamic performance of a future potential reusable launch vehicle. Information from the LASRE experiment will help Lockheed Martin maximize its design for a future potential reusable launch vehicle. It gave Lockheed an understanding of the performance of the lifting body and linear aerospike engine combination even before the X-33 Advanced Technology Demonstrator flies. LASRE was a small, half-span model of a lifting body with eight thrust cells of an aerospike engine. The experiment, mounted on the back of an SR-71 aircraft, operates like a kind of 'flying wind tunnel.' The experiment focused on determining how the engine plume of a reusable launch vehicle engine plume would affect the aerodynamics of its lifting body shape at specific altitudes and speeds reaching approximately 750 miles per hour. The interaction of the aerodynamic flow with the engine plume could create drag; design refinements look to minimize that interaction. During the flight research program, the aircraft completed seven research flights. Two initial flights were used to determine the aerodynamic characteristics of the LASRE apparatus on the back of the aircraft. The first of those two flights occurred October 31, 1997. The SR-71 took off at 8:31 a.m. PST. The aircraft flew for one hour and fifty minutes, reaching a

  12. Gas Flow, Particle Acceleration, and Heat Transfer in Cold Spray: A review

    NASA Astrophysics Data System (ADS)

    Yin, Shuo; Meyer, Morten; Li, Wenya; Liao, Hanlin; Lupoi, Rocco

    2016-06-01

    Cold spraying is increasingly attracting attentions from both scientific and industrial communities due to its unique `low-temperature' coating build-up process and its potential applications in the additive manufacturing across a variety of industries. The existing studies mainly focused on the following subjects: particle acceleration and heating, coating build-up, coating formation mechanism, coating properties, and coating applications, among which particle acceleration and heating can be regarded as the premise of the other subjects because it directly determines whether particles have sufficient energy to deposit and form the coating. Investigations on particle acceleration and heating behavior in cold spraying have been widely conducted both numerically and experimentally over decades, where many valuable conclusions were drawn. However, existing literature on this topic is vast; a systematical summery and review work is still lack so far. Besides, some curtail issues involved in modeling and experiments are still not quite clear, which needs to be further clarified. Hence, a comprehensive summary and review of the literature are very necessary. In this paper, the gas flow, particle acceleration, and heat transfer behavior in the cold spray process are systematically reviewed. Firstly, a brief introduction is given to introduce the early analytical models for predicting the gas flow and particle velocity in cold spraying. Subsequently, special attention is directed towards the application of computational fluid dynamics technique for cold spray modeling. Finally, the experimental observations and measurements in cold spraying are summarized.

  13. Rinse trough with improved flow

    DOEpatents

    O`Hern, T.J.; Grasser, T.W.

    1998-08-11

    Novel rinse troughs accomplish thorough uniform rinsing. The troughs are suitable for one or more essentially planar objects having substantially the same shape. The troughs ensure that each surface is rinsed uniformly. The new troughs provide uniform rinse fluid flow over the objects` surfaces to accomplish a more thorough rinse than prior art troughs. 5 figs.

  14. Rinse trough with improved flow

    DOEpatents

    O'Hern, Timothy J.; Grasser, Thomas W.

    1998-01-01

    Novel rinse troughs accomplish thorough uniform rinsing. The troughs are suitable for one or more essentially planar objects having substantially the same shape. The troughs ensure that each surface is rinsed uniformly. The new troughs provide uniform rinse fluid flow over the objects' surfaces to accomplish a more thorough rinse than prior art troughs.

  15. Recommendations to Improve Employee Thermal Comfort When Working in 40°F Refrigerated Cold Rooms.

    PubMed

    Ceballos, Diana; Mead, Kenneth; Ramsey, Jessica

    2015-01-01

    Cold rooms are commonly used for food storage and preparation, and are usually kept around 40°F following food safety guidelines. Some food preparation employees may spend 8 or more hours inside cold rooms. These employees may not be aware of the risks associated with mildly cold temperatures, dampness, and limited ventilation. We performed an evaluation of cold rooms at an airline catering facility because of concerns with exposure to cold temperatures. We spoke with and observed employees in two cold rooms, reviewed daily temperature logs, evaluated employee's physical activity, work/rest schedule, and protective clothing. We measured temperature, percent relative humidity, and air velocities at different work stations inside the cold rooms. We concluded that thermal comfort concerns perceived by cold room employees may have been the result of air drafts at their workstations, insufficient use of personal protective equipment due to dexterity concerns, work practices, and lack of knowledge about good health and safety practices in cold rooms. These moderately cold work conditions with low air velocities are not well covered in current occupational health and safety guidelines, and wind chill calculations do not apply. We provide practical recommendations to improve thermal comfort of cold room employees. Engineering control recommendations include the redesigning of air deflectors and installing of suspended baffles. Administrative controls include the changing out of wet clothing, providing hand warmers outside of cold rooms, and educating employees on cold stress. We also recommended providing more options on personal protective equipment. However, there is a need for guidelines and educational materials tailored to employees in moderately cold environments to improve thermal comfort and minimize health and safety problems.

  16. Recommendations to Improve Employee Thermal Comfort When Working in 40°F Refrigerated Cold Rooms

    PubMed Central

    Ceballos, Diana; Mead, Kenneth; Ramsey, Jessica

    2015-01-01

    Cold rooms are commonly used for food storage and preparation, and are usually kept around 40°F following food safety guidelines. Some food preparation employees may spend 8 or more hours inside cold rooms. These employees may not be aware of the risks associated with mildly cold temperatures, dampness, and limited ventilation. We performed an evaluation of cold rooms at an airline catering facility because of concerns with exposure to cold temperatures. We spoke with and observed employees in two cold rooms, reviewed daily temperature logs, evaluated employee’s physical activity, work/rest schedule, and protective clothing. We measured temperature, percent relative humidity, and air velocities at different work stations inside the cold rooms. We concluded that thermal comfort concerns perceived by cold room employees may have been the result of air drafts at their workstations, insufficient use of personal protective equipment due to dexterity concerns, work practices, and lack of knowledge about good health and safety practices in cold rooms. These moderately cold work conditions with low air velocities are not well covered in current occupational health and safety guidelines, and wind chill calculations do not apply. We provide practical recommendations to improve thermal comfort of cold room employees. Engineering control recommendations include the redesigning of air deflectors and installing of suspended baffles. Administrative controls include the changing out of wet clothing, providing hand warmers outside of cold rooms, and educating employees on cold stress. We also recommended providing more options on personal protective equipment. However, there is a need for guidelines and educational materials tailored to employees in moderately cold environments to improve thermal comfort and minimize health and safety problems. PMID:25961447

  17. The responses of skin blood flow, mean arterial pressure and R-R interval induced by cold stimulation with cold wind and ice water.

    PubMed

    Shibahara, N; Matsuda, H; Umeno, K; Shimada, Y; Itoh, T; Terasawa, K

    1996-11-06

    This study was designed to evaluate the peripheral circulation response to cold wind stimulation. Skin blood flow (SBF), ECG R-R intervals (RRs) and mean arterial pressure (MAP) were measured in ten healthy men under strictly controlled conditions. Cold wind flow and ice water bath were prepared as cold stimulations. The subjects were exposed to each cold stimulation and the values of the responses were simultaneously recorded. The cold wind stimulation reduced SBF (maximally 40.4 +/- 3.2%) and increased MAP (maximally 106.9 +/- 1.3%), but did not affect RRs. On the other hand, all parameters were affected by the ice water stimulation, which reduced SBF to 16.4 +/- 1.2% and RRs to 85.1 +/- 3.0%, and increased MAP to 130.6 +/- 2.4% compared with the control state. All subjects suffered from intense pain during the ice water but not the cold wind stimulation, and two of them were eliminated from this study because of vagotonia. After phentolamine iontophoresis was used to block the receptor of peripheral alpha-adrenergic nerve terminals, the cold wind stimulation did not affect SBF. These results suggest that cold wind stimulation is a useful test for evaluating peripheral alpha-adrenergic nerve function in relation to cold sensation, without increase of RRs and noxious pain.

  18. Cold flow simulation of an internal combustion engine with vertical valves using layering approach

    NASA Astrophysics Data System (ADS)

    Martinas, G.; Cupsa, O. S.; Stan, L. C.; Arsenie, A.

    2015-11-01

    Complying with emission requirements and fuel consumption efficiency are the points which drive any development of internal combustion engine. Refinement of the process of combustion and mixture formation, together with in-cylinder flow refinement, is a requirement, valves and piston bowl and intake exhaust port design optimization is essential. In order to reduce the time for design optimization cycle it is used Computational Fluid Dynamics (CFD). Being time consuming and highly costly caring out of experiment using flow bench testing this methods start to become less utilized. Air motion inside the intake manifold is one of the important factors, which govern the engine performance and emission of multi-cylinder diesel engines. Any cold flow study on IC is targeting the process of identifying and improving the fluid flow inside the ports and the combustion chamber. This is only the base for an optimization process targeting to increase the volume of air accessing the combustion space and to increase the turbulence of the air at the end of the compression stage. One of the first conclusions will be that the valve diameter is a fine tradeoff between the need for a bigger diameter involving a greater mass of air filling the cylinder, and the need of a smaller diameter in order to reduce the blind zone. Here there is room for optimization studies. The relative pressure indicates a suction effect coming from the moving piston. The more the shape of the inlet port is smoother and the diameter of the piston is bigger, the aerodynamic resistance of the geometry will be smaller so that the difference of inlet port pressure and the pressure near to piston face will be smaller. Here again there is enough room for more optimization studies.

  19. Warm-Season Flows in Cold-Season Ravines

    NASA Image and Video Library

    2015-05-06

    Ravines or very large gullies are actively forming on Mars during the coldest times of year, when carbon dioxide frost aids mass wasting as seen by NASA Mars Reconnaissance Orbiter. However, some of these ravines also show activity in the warmest time of year, in the form of recurring slope lineae (RSL); dark, narrow flows in some alcoves that flow part way down the channels. Few topographic changes have been seen in association with RSL, and they appear to be seeps of water that seasonally extend down slopes, then fade when inactive, and recur each warm season. Could the RSL activity carve the ravines? In some places the RSL extend to the ends of the fans and appear to match in scale, and perhaps gradually form the ravines. In other places, such as this image, the ravines are much larger than the RSL, so presently-observed RSL flow did not produce the larger landforms, but maybe the flow was greater in the past or maybe the RSL just follow the topography created by other processes. The largest ravines are on pole-facing slopes in the middle latitudes, where RSL have never been seen to form, unless the ravine creates a small equator-facing slope. http://photojournal.jpl.nasa.gov/catalog/PIA19458

  20. An Investigation of Low Marangoni Number Fluid Flow in a Cold Corner

    DTIC Science & Technology

    1993-06-01

    investigated by Marangoni (1871) and the effect is sometimes referred to as " Marangoni flow" [Ref. 31. If the gradient is perpendicular to the interface, a...earlier, this project concentrates on the effect of temperature and velocity in the cold corner region at various Marangoni numbers. The problem is...the convective effects of higher Marangoni number flows, the con- ductive case M = 0 is used as a comparative base. With M = 0, no effects of

  1. Navier-Stokes analysis of cold scramjet-afterbody flows

    NASA Technical Reports Server (NTRS)

    Baysal, Oktay; Engelund, Walter C.; Eleshaky, Mohamed E.

    1989-01-01

    The progress of two efforts in coding solutions of Navier-Stokes equations is summarized. The first effort concerns a 3-D space marching parabolized Navier-Stokes (PNS) code being modified to compute the supersonic mixing flow through an internal/external expansion nozzle with multicomponent gases. The 3-D PNS equations, coupled with a set of species continuity equations, are solved using an implicit finite difference scheme. The completed work is summarized and includes code modifications for four chemical species, computing the flow upstream of the upper cowl for a theoretical air mixture, developing an initial plane solution for the inner nozzle region, and computing the flow inside the nozzle for both a N2/O2 mixture and a Freon-12/Ar mixture, and plotting density-pressure contours for the inner nozzle region. The second effort concerns a full Navier-Stokes code. The species continuity equations account for the diffusion of multiple gases. This 3-D explicit afterbody code has the ability to use high order numerical integration schemes such as the 4th order MacCormack, and the Gottlieb-MacCormack schemes. Changes to the work are listed and include, but are not limited to: (1) internal/external flow capability; (2) new treatments of the cowl wall boundary conditions and relaxed computations around the cowl region and cowl tip; (3) the entering of the thermodynamic and transport properties of Freon-12, Ar, O, and N; (4) modification to the Baldwin-Lomax turbulence model to account for turbulent eddies generated by cowl walls inside and external to the nozzle; and (5) adopting a relaxation formula to account for the turbulence in the mixing shear layer.

  2. Navier-Stokes analysis of cold scramjet-afterbody flows

    NASA Astrophysics Data System (ADS)

    Baysal, Oktay; Engelund, Walter C.; Eleshaky, Mohamed E.

    1989-04-01

    The progress of two efforts in coding solutions of Navier-Stokes equations is summarized. The first effort concerns a 3-D space marching parabolized Navier-Stokes (PNS) code being modified to compute the supersonic mixing flow through an internal/external expansion nozzle with multicomponent gases. The 3-D PNS equations, coupled with a set of species continuity equations, are solved using an implicit finite difference scheme. The completed work is summarized and includes code modifications for four chemical species, computing the flow upstream of the upper cowl for a theoretical air mixture, developing an initial plane solution for the inner nozzle region, and computing the flow inside the nozzle for both a N2/O2 mixture and a Freon-12/Ar mixture, and plotting density-pressure contours for the inner nozzle region. The second effort concerns a full Navier-Stokes code. The species continuity equations account for the diffusion of multiple gases. This 3-D explicit afterbody code has the ability to use high order numerical integration schemes such as the 4th order MacCormack, and the Gottlieb-MacCormack schemes. Changes to the work are listed and include, but are not limited to: (1) internal/external flow capability; (2) new treatments of the cowl wall boundary conditions and relaxed computations around the cowl region and cowl tip; (3) the entering of the thermodynamic and transport properties of Freon-12, Ar, O, and N; (4) modification to the Baldwin-Lomax turbulence model to account for turbulent eddies generated by cowl walls inside and external to the nozzle; and (5) adopting a relaxation formula to account for the turbulence in the mixing shear layer.

  3. MODELING THE STAR-FORMING UNIVERSE AT z = 2: IMPACT OF COLD ACCRETION FLOWS

    SciTech Connect

    Khochfar, Sadegh; Silk, Joseph

    2009-07-20

    We present results of a semianalytic model (SAM) that includes cold accretion and a porosity-based prescription for star formation. We can recover the puzzling observational results of low V/{sigma} seen in various massive disk or disk-like galaxies, if we allow 18% of the accretion energy from cold flows to drive turbulence in gaseous disks at z = 2. The increase of gas mass through cold flows is by itself not sufficient to increase the star formation rate sufficiently to recover the number density of M-dot{sub *}>120 M{sub odot} yr{sup -1} galaxies in our model. In addition, it is necessary to increase the star formation efficiency. This can be achieved naturally in the porosity model, where star formation efficiency scales {proportional_to}{sigma}, which scales as cloud velocity dispersion. As cold accretion is the main driver for gas velocity dispersion in our model, star formation efficiency parallels cold accretion rates and allows fast conversion into stars. At z {approx} 2, we find a space density 10{sup -4} Mpc{sup -3} in star-forming galaxies with M-dot{sub *}>120 M{sub odot} yr{sup -1}, in better agreement than earlier estimates from SAMs. However, the fundamental relation between M-dot{sub *} and M {sub *} is still offset from the observed relation, indicating the need for possibly more efficient star formation at high-z perhaps associated with a role for active galactic nucleus (AGN) triggering.

  4. Improved Ultrasonic Transducer For Measuring Cryogenic Flow

    NASA Technical Reports Server (NTRS)

    Barkhoudarian, Sarkis

    1991-01-01

    Improved ultrasonic transducer used to measure flow of cryogenic fluid. Includes wedge made nonintrusive by machining it out of bulk material of duct carrying fluid. Skewed surfaces of wedge suppress standing waves, thus reducing ringing and increasing signal-to-noise ratio. Increases accuracy of measurements of times of arrival of ultrasonic pulses, from which times flow inferred.

  5. Cold climate mapping using satellite high resolution thermal imagery. [weather forecasting improvement

    NASA Technical Reports Server (NTRS)

    Bartholic, J. F.; Sutherland, R. A.

    1977-01-01

    In an attempt to improve cold climate mapping and freeze forecasting techniques, thermal imagery from the NOAA-2 and -3 satellites and the Synchronous Meteorological Satellite (SMS) were obtained and analyzed. Enhanced image transparencies showed detailed temperature patterns over the peninsula of Florida. The analysis was superior to hand-drawn isotherms drawn from the 300 to 500 thermograph stations presently in use. Satellite data on several cold nights with similar synoptic conditions showed that similar cold patterns existed. Thus, cold climate mapping is possible.

  6. Cold climate mapping using satellite high resolution thermal imagery. [weather forecasting improvement

    NASA Technical Reports Server (NTRS)

    Bartholic, J. F.; Sutherland, R. A.

    1977-01-01

    In an attempt to improve cold climate mapping and freeze forecasting techniques, thermal imagery from the NOAA-2 and -3 satellites and the Synchronous Meteorological Satellite (SMS) were obtained and analyzed. Enhanced image transparencies showed detailed temperature patterns over the peninsula of Florida. The analysis was superior to hand-drawn isotherms drawn from the 300 to 500 thermograph stations presently in use. Satellite data on several cold nights with similar synoptic conditions showed that similar cold patterns existed. Thus, cold climate mapping is possible.

  7. Interactions between gravity waves and cold air outflows in a stably stratified uniform flow

    NASA Technical Reports Server (NTRS)

    Lin, Yuh-Lang; Wang, Ting-An; Weglarz, Ronald P.

    1993-01-01

    Interactions between gravity waves and cold air outflows in a stably stratified uniform flow forced by various combinations of prescribed heat sinks and sources are studied using a hydrostatic two-dimensional nonlinear numerical model. The formation time for the development of a stagnation point or reversed flow at the surface is not always directly proportional to the Froude number when wave reflections exist from upper levels. A density current is able to form by the wave-otuflow interaction, even though the Froude number is greater than a critical value. This is the result of the wave-outflow interaction shifting the flow response to a different location in the characteristic parameter space. A density current is able to form or be destroyed due to the wave-outflow interaction between a traveling gravity wave and cold air outflow. This is proved by performing experiments with a steady-state heat sink and an additional transient heat source. In a quiescent fluid, a region of cold air, convergence, and upward motion is formed after the collision between two outflows produced by two prescribed heat sinks. After the collision, the individual cold air outflows lose their own identity and merge into a single, stationary, cold air outflow region. Gravity waves tend to suppress this new stationary cold air outflow after the collision. The region of upward motion associated with the collision is confined to a very shallow layer. In a moving airstream, a density current produced by a heat sink may be suppressed or enhanced nonlinearly by an adjacent heat sink due to the wave-outflow interaction.

  8. Interactions between gravity waves and cold air outflows in a stably stratified uniform flow

    NASA Technical Reports Server (NTRS)

    Lin, Yuh-Lang; Wang, Ting-An; Weglarz, Ronald P.

    1993-01-01

    Interactions between gravity waves and cold air outflows in a stably stratified uniform flow forced by various combinations of prescribed heat sinks and sources are studied using a hydrostatic two-dimensional nonlinear numerical model. The formation time for the development of a stagnation point or reversed flow at the surface is not always directly proportional to the Froude number when wave reflections exist from upper levels. A density current is able to form by the wave-otuflow interaction, even though the Froude number is greater than a critical value. This is the result of the wave-outflow interaction shifting the flow response to a different location in the characteristic parameter space. A density current is able to form or be destroyed due to the wave-outflow interaction between a traveling gravity wave and cold air outflow. This is proved by performing experiments with a steady-state heat sink and an additional transient heat source. In a quiescent fluid, a region of cold air, convergence, and upward motion is formed after the collision between two outflows produced by two prescribed heat sinks. After the collision, the individual cold air outflows lose their own identity and merge into a single, stationary, cold air outflow region. Gravity waves tend to suppress this new stationary cold air outflow after the collision. The region of upward motion associated with the collision is confined to a very shallow layer. In a moving airstream, a density current produced by a heat sink may be suppressed or enhanced nonlinearly by an adjacent heat sink due to the wave-outflow interaction.

  9. The contribution of blood flow to the skin temperature responses during a cold sensitivity test.

    PubMed

    Davey, Martha; Eglin, Clare; House, James; Tipton, Michael

    2013-09-01

    The presumption in a cold sensitivity test (CST) used for cold injuries is that the skin temperature (T sk) observed reflects the return of blood flow to the extremity following a local cold challenge. We questioned this assumption. Six non-cold injured participants undertook two CSTs in 30 °C air. The control (CON) CST involved 12 min gentle exercise prior to immersing the foot into 15 °C water for 2 min followed by 15 min of spontaneous rewarming. The occlusion (OCC) CST was the same except that blood flow to the foot was occluded during the rewarming period. These results were compared to CSTs from six individuals with non-freezing cold injury and moderate-severe cold sensitivity (CS) and a non-perfused human digit model (NPDM). Before immersion, great toe skin blood flow (SkBF) was similar in CON and OCC conditions [255 (107) laser Doppler units (LDU)] and was higher than CS [59 (52) LDU]. During rewarming, SkBF in CON returned to 104 % of the pre-immersion value and was higher than both OCC and CS. Great toe T sk before immersion was lower in CS [28.5 (2.1) °C] compared to CON [34.7 (0.4) °C], OCC [34.6 (0.9) °C] and NPDM [35.0 (0.4) °C]. During rewarming skin/surface temperature in OCC, CS and NPDM were similar and all lower than CON. SkBF does contribute to the skin rewarming profile during a CST as a faster rate of rewarming was observed in CON compared to either OCC or NPDM. The lower T sk in CS may be due to a reduced basal SkBF.

  10. Cold Plasma: an emerging antimicrobial intervention to improve food safety

    USDA-ARS?s Scientific Manuscript database

    Contamination of fresh and fresh-cut fruits and vegetables by foodborne pathogens has prompted research into novel interventions. Cold plasma is a nonthermal food processing technology which uses energetic, reactive gases to inactivate contaminating microbes. This flexible sanitizing method uses ele...

  11. Plant plasma membrane proteomics for improving cold tolerance.

    PubMed

    Takahashi, Daisuke; Li, Bin; Nakayama, Takato; Kawamura, Yukio; Uemura, Matsuo

    2013-01-01

    Plants are always exposed to various stresses. We have focused on freezing stress, which causes serious problems for agricultural management. When plants suffer freeze-induced damage, the plasma membrane is thought to be the primary site of injury because of its central role in regulation of various cellular processes. Cold tolerant species, however, adapt to such freezing conditions by modifying cellular components and functions (cold acclimation). One of the most important adaptation mechanisms to freezing is alteration of plasma membrane compositions and functions. Advanced proteomic technologies have succeeded in identification of many candidates that may play roles in adaptation of the plasma membrane to freezing stress. Proteomics results suggest that adaptations of plasma membrane functions to low temperature are associated with alterations of protein compositions during cold acclimation. Some of proteins identified by proteomic approaches have been verified their functional roles in freezing tolerance mechanisms further. Thus, accumulation of proteomic results in the plasma membrane is of importance for application to molecular breeding efforts to increase cold tolerance in crops.

  12. Linear Aerospike SR-71 Experiment (LASRE) dumps water after first in-flight cold flow test

    NASA Technical Reports Server (NTRS)

    1998-01-01

    The NASA SR-71A successfully completed its first cold flow flight as part of the NASA/Rocketdyne/Lockheed Martin Linear Aerospike SR-71 Experiment (LASRE) at NASA's Dryden Flight Research Center, Edwards, California on March 4, 1998. During a cold flow flight, gaseous helium and liquid nitrogen are cycled through the linear aerospike engine to check the engine's plumbing system for leaks and to check the engine operating characterisitics. Cold-flow tests must be accomplished successfully before firing the rocket engine experiment in flight. The SR-71 took off at 10:16 a.m. PST. The aircraft flew for one hour and fifty-seven minutes, reaching a maximum speed of Mach 1.58 before landing at Edwards at 12:13 p.m. PST. 'I think all in all we had a good mission today,' Dryden LASRE Project Manager Dave Lux said. Flight crew member Bob Meyer agreed, saying the crew 'thought it was a really good flight.' Dryden Research Pilot Ed Schneider piloted the SR-71 during the mission. Lockheed Martin LASRE Project Manager Carl Meade added, 'We are extremely pleased with today's results. This will help pave the way for the first in-flight engine data-collection flight of the LASRE.' The LASRE experiment was designed to provide in-flight data to help Lockheed Martin evaluate the aerodynamic characteristics and the handling of the SR-71 linear aerospike experiment configuration. The goal of the project was to provide in-flight data to help Lockheed Martin validate the computational predictive tools it was using to determine the aerodynamic performance of a future reusable launch vehicle. The joint NASA, Rocketdyne (now part of Boeing), and Lockheed Martin Linear Aerospike SR-71 Experiment (LASRE) completed seven initial research flights at Dryden Flight Research Center. Two initial flights were used to determine the aerodynamic characteristics of the LASRE apparatus (pod) on the back of the SR-71. Five later flights focused on the experiment itself. Two were used to cycle gaseous

  13. Improving cash flow through benchmarking.

    PubMed

    Nelson, B

    1994-09-01

    Healthcare organizations can use two benchmarking techniques to improve their accounts receivable departments' performance: 1) studying the accounts receivable statistics of model healthcare organizations, and 2) visiting these model organizations in order to get a first-hand look at how they do business. Employing these two benchmarking techniques can help healthcare organizations reduce gross days revenue outstanding, bad debt, the length of time between the date a patient is discharged and the date a bill is mailed, the total percentage of receivables more than 90 days old, and general business office expenses related to collection.

  14. Improved Flow-Controlling Vortex Generator

    NASA Technical Reports Server (NTRS)

    Collins, Earl R., Jr.; Marner, Wilbur J.; Rohatgi, Naresh K.

    1989-01-01

    Symmetrical tangential streams control flow of radial primary streams. Vortex generator uses small secondary stream of fluid to control normally-larger primary stream. Improved version of vortex generator described in "Variable Control Port for Fluidic Control Device," (NPO-16603). Secondary, or control, flows entering tangentially through diametrically opposite ports set up swirling motion restraining primary flow. Pressure of secondary fluid in relation to primary fluid controlling factor. Like valve, vortex generator varies rate of flow of primary fluid from maximum value down to zero. When properly designed, requires low pressure differential between primary and secondary streams and expends relatively small amount of secondary fluid.

  15. Simulation of Cold Flow in a Truncated Ideal Nozzle with Film Cooling

    NASA Technical Reports Server (NTRS)

    Braman, Kalen; Ruf, Joseph

    2015-01-01

    Flow transients during rocket start-up and shut-down can lead to significant side loads on rocket nozzles. The capability to estimate these side loads computationally can streamline the nozzle design process. Towards this goal, the flow in a truncated ideal contour (TIC) nozzle has been simulated for a range of nozzle pressure ratios (NPRs) aimed to match a series of cold flow experiments performed at the NASA MSFC Nozzle Test Facility. These simulations were performed with varying turbulence model choices and with four different versions of the TIC nozzle model geometry, each of which was created with a different simplification to the test article geometry.

  16. Fluid Structure Interaction in a Cold Flow Test and Transient CFD Analysis of Out-of-Round Nozzles

    NASA Technical Reports Server (NTRS)

    Ruf, Joseph; Brown, Andrew; McDaniels, David; Wang, Ten-See

    2010-01-01

    This viewgraph presentation describes two nozzle fluid flow interactions. They include: 1) Cold flow nozzle tests with fluid-structure interaction at nozzle separated flow; and 2) CFD analysis for nozzle flow and side loads of nozzle extensions with various out-of-round cases.

  17. Ambient cold air decreased nasal mucosa blood flow measured by laser Doppler flowmeter.

    PubMed

    Chu, Yueng-Hsiang; Lu, Da-Wen; Wang, Hsing-Won

    2010-06-01

    With its potentially conflicting physiological roles of both air-conditioning and body-heat recovery, the response of nasal mucosa blood flow (NMBF) to ambient cold air is not well understood. To evaluate the NMBF in response to cold ambient air. The NMBF was continuously measured by laser Doppler flowmetry in nine participants exposed to different air temperatures (24 degrees C and 4 degrees C). The NMBF significantly decreased at 4 degrees C compared with that at 24 degrees C (p < 0.01). The response to ambient cold air in the nasal microcirculation is similar to that of the body-surface blood vessels, suggesting that body-heat recovery rather than air-conditioning is the predominant function.

  18. Cold-Flow Circulating Fluidized-Bed Identification

    SciTech Connect

    Parviz Famouri

    2005-07-01

    In a variety of industrial applications, the use of a circulating fluidized bed (CFB) provides various advantages, such as reducing environmental pollution and increasing process efficiency. The application of circulating fluidized bed technology contributes to the improvement of gas-solid contact, reduction of the cross-sectional area with the use of higher superficial velocities, the use of the solids circulation rate as an additional control variable, and superior radial mixing, Grace et al. [1]. In order to improve raw material usage and utility consumption, optimization and control of CFB is very important, and an accurate, real time model is required to describe and quantify the process. Currently there is no accepted way to construct a reliable model for such a complex CFB system using traditional methods, especially at the pilot or industrial scale. Three major obstacles in characterizing the system are: 1) chaotic nature of the system; 2) non-linearity of the system, and 3) number of immeasurable unknowns internal to the system,[2]. Advanced control theories and methods have the ability to characterize the system, and can overcome all three of these obstacles. These methods will be discussed in this report.

  19. Effects of cold dry air nasal stimulation on airway mucosal blood flow in humans.

    PubMed

    Le Merre, C; Isber, J; Chediak, A D; Wanner, A

    2003-10-01

    Several studies have demonstrated that nasal challenges can induce reflex responses in the respiratory system. Some authors have described bronchoconstriction and modification of the pattern of breathing following nasal challenges by irritants and cold air. We propose to determine the effect of nasal stimulation with cold dry air on airway mucosal blood flow (Qaw) in the proximal tracheal bronchial tree of healthy humans. Nine healthy subjects participated in the study. Baseline measurement Qaw, nasal airway resistance (NAR) and airway caliber by specific airways conductance (SGaw) were followed by nasal challenge with cold dry air. Qaw, NAR and Sgaw were determined after the challenge. In those subjects in which a significant decline in Qaw was recorded the protocol was repeated after pretreatment with nasal anesthesia using topical lidocaine. Cold dry air challenge produced a significant decrease in mean Qaw for the nine subjects and this response was abolished by pretreatment with nasal anesthesia using topical lidocaine. There was no significant change in Sgaw and NAR after the challenge and topical lidocaine anesthesia. Our data indicates that nasal stimulation with cold dry air leads to a reduction in Qaw and that this effect may be mediated by a nasal reflex.

  20. COLD TRAP

    DOEpatents

    Milleron, N.

    1963-03-12

    An improved linear-flow cold trap is designed for highvacuum applications such as mitigating back migration of diffusion pump oil moiecules. A central pot of liquid nitrogen is nested within and supported by a surrounding, vertical, helical coil of metai sheet, all enveloped by a larger, upright, cylindrical, vacuum vessel. The vertical interstices between successive turns of the coil afford lineal, axial, high-vacuum passages between open mouths at top and bottom of said vessel, while the coil, being cold by virtue of thermal contact of its innermost turn with the nitrogen pot, affords expansive proximate condensation surfaces. (AEC)

  1. Activation of scleral cold thermoreceptors by temperature and blood flow changes.

    PubMed

    Gallar, Juana; Acosta, M Carmen; Belmonte, Carlos

    2003-02-01

    To study the response of scleral cold receptors located in areas of the eye unexposed to temperature and blood flow changes. In anesthetized cats, the neural activity was recorded from single, cold-sensory fibers of the ciliary nerves innervating the sclera and limbus. Controlled temperature changes of the receptive field were performed with a contact thermode. Ocular blood flow reductions were obtained by occluding the ipsilateral common carotid artery for 30 to 60 seconds with a compressor placed around the artery. Local blood flow was measured with a laser Doppler flowmeter. Temperature was measured with a microprobe introduced in the subscleral space. Ocular sympathetic stimulation was performed with a pair of silver electrodes placed on the preganglionic cervical sympathetic trunk. To induce local hypoxia, N(2) was applied on the scleral surface with a specially designed chamber. For systemic hypoxia the breathing air was replaced with a gas mixture containing 10% O(2) in N(2). Sensory nerve fibers identified as cold receptors exhibited ongoing nerve activity in bursts at 35 degrees C and responded to cooling pulses applied to their receptive fields with an increase in the impulse discharge that reached a peak and decayed gradually to a lower level. When temperature was reduced from 35 degrees C to 34 degrees C, frequency increased monotonically with decreasing temperature of the sclera. Between 35 degrees C and 30 degrees C, peak and mean frequencies were roughly proportional to temperature of the sclera. The characteristics of burst discharges also depended on scleral temperature. Electrical stimulation of the cervical sympathetic trunk induced a decrease in blood flow and temperature and evoked an increase in the firing frequency of cold-sensory fibers that was proportional to the frequency of stimulating pulses. Carotid occlusion also elicited an increase of the discharge of cold thermoreceptor fibers that occurred in parallel with a decrease in blood flow

  2. Business office innovations improve hospital cash flow.

    PubMed

    Anderson, H J

    1991-04-05

    The business office accounts for a major portion of hospitals' administrative and financial expenses. And, in the current shaky economic climate, hospitals faced with slowdowns and cutbacks in payments from a variety of sources are scrambling to come up with innovative ways to improve cash flow. "The hospital that has good cash flow will be the one able to survive," says George Arges, a senior policy analyst at the American Hospital Association's Division of Policy and Capital Finance in Chicago.

  3. Development of an Empirical Methods for Predicting Jet Mixing Noise of Cold Flow Rectangular Jets

    NASA Technical Reports Server (NTRS)

    Russell, James W.

    1999-01-01

    This report presents an empirical method for predicting the jet mixing noise levels of cold flow rectangular jets. The report presents a detailed analysis of the methodology used in development of the prediction method. The empirical correlations used are based on narrow band acoustic data for cold flow rectangular model nozzle tests conducted in the NASA Langley Jet Noise Laboratory. There were 20 separate nozzle test operating conditions. For each operating condition 60 Hz bandwidth microphone measurements were made over a frequency range from 0 to 60,000 Hz. Measurements were performed at 16 polar directivity angles ranging from 45 degrees to 157.5 degrees. At each polar directivity angle, measurements were made at 9 azimuth directivity angles. The report shows the methods employed to remove screech tones and shock noise from the data in order to obtain the jet mixing noise component. The jet mixing noise was defined in terms of one third octave band spectral content, polar and azimuth directivity, and overall power level. Empirical correlations were performed over the range of test conditions to define each of these jet mixing noise parameters as a function of aspect ratio, jet velocity, and polar and azimuth directivity angles. The report presents the method for predicting the overall power level, the average polar directivity, the azimuth directivity and the location and shape of the spectra for jet mixing noise of cold flow rectangular jets.

  4. Linear Aerospike SR-71 Experiment (LASRE) dumps water after first in-flight cold flow test

    NASA Image and Video Library

    1998-03-04

    The NASA SR-71A successfully completed its first cold flow flight as part of the NASA/Rocketdyne/Lockheed Martin Linear Aerospike SR-71 Experiment (LASRE) at NASA's Dryden Flight Research Center, Edwards, California on March 4, 1998. During a cold flow flight, gaseous helium and liquid nitrogen are cycled through the linear aerospike engine to check the engine's plumbing system for leaks and to check the engine operating characterisitics. Cold-flow tests must be accomplished successfully before firing the rocket engine experiment in flight. The SR-71 took off at 10:16 a.m. PST. The aircraft flew for one hour and fifty-seven minutes, reaching a maximum speed of Mach 1.58 before landing at Edwards at 12:13 p.m. PST. "I think all in all we had a good mission today," Dryden LASRE Project Manager Dave Lux said. Flight crew member Bob Meyer agreed, saying the crew "thought it was a really good flight." Dryden Research Pilot Ed Schneider piloted the SR-71 during the mission. Lockheed Martin LASRE Project Manager Carl Meade added, "We are extremely pleased with today's results. This will help pave the way for the first in-flight engine data-collection flight of the LASRE."

  5. Nicorandil pretreatment and improved myocardial protection during cold blood cardioplegia.

    PubMed

    Li, Y; Iguchi, A; Tsuru, Y; Nakame, T; Satou, K; Tabayashi, K

    2000-01-01

    The present study was designed to assess whether pretreatment with nicorandil enhanced myocardial protection provided by cold (15 degrees C) high-potassium (25 mmol/l) blood cardioplegia during open heart surgery. Subjects were 40 patients with a variety of acquired heart diseases undergoing cardiac surgery involved cardiopulmonary bypass. They were randomly divided into two groups, 25 pretreated nicorandil (0.3 mg/kg) 30 minutes before aortic cross clamping, 15 not pretreated. After aortic cross clamping, the initial dose of cardioplegic solution (10 ml/kg) was administered through the ascending aorta and supplemental doses of cardioplegia (5 ml/kg) given each 30 minutes thereafter. Preoperative and postoperative cardiac troponin-T, myosin light chain 1 and cardiac enzymes were measured and hemodynamic data recorded. Postoperative serum creatine kinase and myosin light chain 1 were significantly lower in the nicorandil pretreatment group than in controls. Serum glutamic oxalacetic transaminase and troponin-T were lower and cardiac output was higher after surgery in the nicorandil group, although not statistically significant. This data suggests that pretreatment with nicorandil enhances the myocardial protection achieved by cold blood cardioplegia.

  6. Improvement of cutaneous microcirculation by cold atmospheric plasma (CAP): Results of a controlled, prospective cohort study.

    PubMed

    Kisch, Tobias; Helmke, Andreas; Schleusser, Sophie; Song, Jungin; Liodaki, Eirini; Stang, Felix Hagen; Mailaender, Peter; Kraemer, Robert

    2016-03-01

    Cold atmospheric plasma (CAP) has proven its benefits in the reduction of various bacteria and fungi in both in vitro and in vivo studies. Moreover, CAP generated by dielectric barrier discharge (DBD) promoted wound healing in vivo. Charged particles, chemically reactive species (such as O3, OH, H2O2, O, NxOy), ultraviolet radiation (UV-A and UV-B), strong oscillating electric fields as well as weak electric currents are produced by DBD operated in air. However, wound healing is a complex process, depending on nutrient and oxygen supply via cutaneous blood circulation. Therefore, this study examined the effects of CAP on cutaneous microcirculation in a prospective cohort setting. Cold atmospheric plasma application enhances cutaneous microcirculation. Microcirculatory data of 20 healthy subjects (11 males, 9 females; mean age 35.2 ± 13.8 years; BMI 24.3 ± 3.1 kg/m(2)) were recorded continuously at a defined skin area at the radial forearm. Under standardized conditions, microcirculatory measurements were performed using a combined laser Doppler and photospectrometry system. After baseline measurement, CAP was applied by a DBD plasma device for 90 s to the same defined skin area of 22.5 cm(2). Immediately after the application cutaneous microcirculation was assessed for 30 min at the same site. After CAP application, tissue oxygen saturation immediately increased by 24% (63.8 ± 13.8% from 51.4 ± 13.2% at baseline, p<0.001) and stayed significantly elevated for 8 min. Cutaneous blood flow increased by 73% (41.0 ± 31.2 AU from 23.7 ± 20.8 AU at baseline, p<0.001) and remained upregulated for 11 min. Furthermore, cutaneous blood flow showed two peaks at 14 (29.8 ± 25.0 AU, p=0.049) and 19 min (29.8 ± 22.6 AU, p=0.048) after treatment. Postcapillary venous filling pressure continuously increased, but showed no significant change vs. baseline in the non-specific BMI group. Subgroup analysis revealed that tissue oxygen saturation, postcapillary venous filling

  7. Influence of cold water immersion on limb and cutaneous blood flow at rest.

    PubMed

    Gregson, Warren; Black, Mark A; Jones, Helen; Milson, Jordon; Morton, James; Dawson, Brian; Atkinson, Greg; Green, Daniel J

    2011-06-01

    Cold water immersion reduces exercise-induced muscle damage. Benefits may partly arise from a decline in limb blood flow; however, no study has comprehensively investigated the influence of different degrees of cooling undertaken via cold water immersion on limb blood flow responses. To determine the influence of cold (8°C) and cool (22°C) water immersion on lower limb and cutaneous blood flow. Controlled laboratory study. Nine men were placed in a semireclined position and lowered into 8°C or 22°C water to the iliac crest for two 5-minute periods interspersed with 2 minutes of nonimmersion. Rectal and thigh skin temperature, deep and superficial muscle temperature, heart rate, mean arterial pressure, thigh cutaneous blood velocity (laser Doppler), and superficial femoral artery blood flow (duplex ultrasound) were measured during immersion and for 30 minutes after immersion. Indices of vascular conductance were calculated (flux and blood flow/mean arterial pressure). Reductions in rectal temperature (8°C, 0.2° ± 0.1°C; 22°C, 0.1° ± 0.1°C) and thigh skin temperature (8°C, 6.2° ± 0.5°C; 22°C, 3.2° ± 0.2°C) were greater in 8°C water than in 22°C (P < .01). Femoral artery conductance was reduced to a similar extent immediately after immersion (~30%) and 30 minutes after immersion (~40%) under both conditions (P < .01). In contrast, there was less thigh cutaneous vasoconstriction during and after immersion in 8°C water compared with 22°C (P = .01). These data suggest that immersion at both temperatures resulted in similar whole limb blood flow but, paradoxically, more blood was distributed to the skin in the colder water. This suggests that colder temperatures may be associated with reduced muscle blood flow, which could provide an explanation for the benefits of cold water immersion in alleviating exercise-induced muscle damage in sports and athletic contexts. Colder water temperatures may be more effective in the treatment of exercise

  8. Efficacy of keishibukuryogan, a traditional Japanese herbal medicine, in treating cold sensation and numbness after stroke: clinical improvement and skin temperature normalization in 22 stroke patients.

    PubMed

    Fujita, Keishi; Yamamoto, Tetsuya; Kamezaki, Takao; Matsumura, Akira

    2010-01-01

    Cold sensation and numbness have been reported as post-stroke sensory sequelae attributable to distal axonopathy, which is caused by chronic ischemia of diseased limbs resulting from dysfunction of vasomotor regulatory systems. Keishibukuryogan is a traditional herbal medicine used to treat symptoms of peripheral ischemia such as cold extremities. This study investigated clinical improvement and skin temperature in peripheral ischemia patients to determine the efficacy of keishibukuryogan in alleviating post-stroke cold sensation and numbness. Twenty-two stroke patients with cold sensation and/or numbness were enrolled in this study. Subjective cold sensation and numbness, evaluated using the visual analogue scale, were found in 21 and 31 limbs, respectively. The skin temperature of diseased and healthy limbs was recorded. We observed all patients for 4 weeks and 17 patients for 8 weeks after administration of keishibukuryogan. The skin temperature of diseased limbs was significantly higher than baseline at 4 weeks and 8 weeks, whereas that of healthy limbs did not change significantly. Cold sensation and numbness were significantly improved at 4 weeks and 8 weeks compared to baseline. Keishibukuryogan administration resulted in warming of diseased limbs and improved cold sensation and numbness, probably by increasing peripheral blood flow.

  9. Influence of cold-water immersion on limb blood flow after resistance exercise.

    PubMed

    Mawhinney, Chris; Jones, Helen; Low, David A; Green, Daniel J; Howatson, Glyn; Gregson, Warren

    2017-06-01

    This study determined the influence of cold (8°C) and cool (22°C) water immersion on lower limb and cutaneous blood flow following resistance exercise. Twelve males completed 4 sets of 10-repetition maximum squat exercise and were then immersed, semi-reclined, into 8°C or 22°C water for 10-min, or rested in a seated position (control) in a randomized order on different days. Rectal and thigh skin temperature, muscle temperature, thigh and calf skin blood flow and superficial femoral artery blood flow were measured before and after immersion. Indices of vascular conductance were calculated (flux and blood flow/mean arterial pressure). The colder water reduced thigh skin temperature and deep muscle temperature to the greatest extent (P < .001). Reductions in rectal temperature were similar (0.2-0.4°C) in all three trials (P = .69). Femoral artery conductance was similar after immersion in both cooling conditions, with both conditions significantly lower (55%) than the control post-immersion (P < .01). Similarly, there was greater thigh and calf cutaneous vasoconstriction (40-50%) after immersion in both cooling conditions, relative to the control (P < .01), with no difference between cooling conditions. These findings suggest that cold and cool water similarly reduce femoral artery and cutaneous blood flow responses but not muscle temperature following resistance exercise.

  10. Improving ecological response monitoring of environmental flows.

    PubMed

    King, Alison J; Gawne, Ben; Beesley, Leah; Koehn, John D; Nielsen, Daryl L; Price, Amina

    2015-05-01

    Environmental flows are now an important restoration technique in flow-degraded rivers, and with the increasing public scrutiny of their effectiveness and value, the importance of undertaking scientifically robust monitoring is now even more critical. Many existing environmental flow monitoring programs have poorly defined objectives, nonjustified indicator choices, weak experimental designs, poor statistical strength, and often focus on outcomes from a single event. These negative attributes make them difficult to learn from. We provide practical recommendations that aim to improve the performance, scientific robustness, and defensibility of environmental flow monitoring programs. We draw on the literature and knowledge gained from working with stakeholders and managers to design, implement, and monitor a range of environmental flow types. We recommend that (1) environmental flow monitoring programs should be implemented within an adaptive management framework; (2) objectives of environmental flow programs should be well defined, attainable, and based on an agreed conceptual understanding of the system; (3) program and intervention targets should be attainable, measurable, and inform program objectives; (4) intervention monitoring programs should improve our understanding of flow-ecological responses and related conceptual models; (5) indicator selection should be based on conceptual models, objectives, and prioritization approaches; (6) appropriate monitoring designs and statistical tools should be used to measure and determine ecological response; (7) responses should be measured within timeframes that are relevant to the indicator(s); (8) watering events should be treated as replicates of a larger experiment; (9) environmental flow outcomes should be reported using a standard suite of metadata. Incorporating these attributes into future monitoring programs should ensure their outcomes are transferable and measured with high scientific credibility.

  11. Improving the cold flow properties of biodiesel by fractionation

    USDA-ARS?s Scientific Manuscript database

    Production of biodiesel is increasing world-wide and contributing to the growing development of renewable alternative fuels. Biodiesel has many fuel properties such as density, viscosity, lubricity, and cetane number that make it compatible for combustion in compression-ignition (diesel) engines. ...

  12. Simulation of Cold Flow in a Truncated Ideal Nozzle with Film Cooling

    NASA Technical Reports Server (NTRS)

    Braman, K. E.; Ruf, J. H.

    2015-01-01

    Flow transients during rocket start-up and shut-down can lead to significant side loads on rocket nozzles. The capability to estimate these side loads computationally can streamline the nozzle design process. Towards this goal, the flow in a truncated ideal contour (TIC) nozzle has been simulated using RANS and URANS for a range of nozzle pressure ratios (NPRs) aimed to match a series of cold flow experiments performed at the NASA MSFC Nozzle Test Facility. These simulations were performed with varying turbulence model choices and for four approximations of the supersonic film injection geometry, each of which was created with a different simplification of the test article geometry. The results show that although a reasonable match to experiment can be obtained with varying levels of geometric fidelity, the modeling choices made do not fully represent the physics of flow separation in a TIC nozzle with film cooling.

  13. Numerical simulation of tsunami generation by cold volcanic mass flows at Augustine Volcano, Alaska

    USGS Publications Warehouse

    Waythomas, C.F.; Watts, P.; Walder, J.S.

    2006-01-01

    Many of the world's active volcanoes are situated on or near coastlines. During eruptions, diverse geophysical mass flows, including pyroclastic flows, debris avalanches, and lahars, can deliver large volumes of unconsolidated debris to the ocean in a short period of time and thereby generate tsunamis. Deposits of both hot and cold volcanic mass flows produced by eruptions of Aleutian arc volcanoes are exposed at many locations along the coastlines of the Bering Sea, North Pacific Ocean, and Cook Inlet, indicating that the flows entered the sea and in some cases may have initiated tsunamis. We evaluate the process of tsunami generation by cold granular subaerial volcanic mass flows using examples from Augustine Volcano in southern Cook Inlet. Augustine Volcano is the most historically active volcano in the Cook Inlet region, and future eruptions, should they lead to debris-avalanche formation and tsunami generation, could be hazardous to some coastal areas. Geological investigations at Augustine Volcano suggest that as many as 12-14 debris avalanches have reached the sea in the last 2000 years, and a debris avalanche emplaced during an A.D. 1883 eruption may have initiated a tsunami that was observed about 80 km east of the volcano at the village of English Bay (Nanwalek) on the coast of the southern Kenai Peninsula. Numerical simulation of mass-flow motion, tsunami generation, propagation, and inundation for Augustine Volcano indicate only modest wave generation by volcanic mass flows and localized wave effects. However, for east-directed mass flows entering Cook Inlet, tsunamis are capable of reaching the more populated coastlines of the southwestern Kenai Peninsula, where maximum water amplitudes of several meters are possible.

  14. Cold Flow Determination of the Internal Flow Environment Around the Submerged TVC Nozzle for the Space Shuttle SRM

    NASA Technical Reports Server (NTRS)

    Whitesides, R. H.; Ghosh, A.; Jenkins, S. L.; Bacchus, D. L.

    1989-01-01

    A series of subscale cold flow tests was performed to quantify the gas flow characteristics at the aft end of the Space Shuttle Solid Rocket Motor. This information was used to support the analyses of the redesigned nozzle/case joint. A portion of the thermal loads at the joint are due to the circumferential velocities and pressure gradients caused primarily by the gimbaling of the submerged nose TVC nozzle. When the nozzle centerline is vectored with respect to the motor centerline, asymmetries are set up in the flow field under the submerged nozzle and immediately adjacent to the nozzle/case joint. Specific program objectives included: determination of the effects of nozzle gimbal angle and propellant geometry on the circumferential flow field; measurement of the static pressure and gas velocities in the vicinity of the nozzle/case joint; use of scaling laws to apply the subscale cold flow data to the full scale SRM; and generation of data for use in validation of 3-D computational fluid dynamic, CFD, models of the SRM flow field. These tests were conducted in the NASA Marshall Space Flight Center Airflow Facility with a 7.5 percent scale model of the aft segment of the SRM. Static and dynamic pressures were measured in the model to quantify the flow field. Oil flow data was also acquired to obtain qualitative visual descriptions of the flow field. Nozzle gimbal angles of 0, 3.5, and 7 deg were used with propellant grain configurations corresponding to motor burn times of 0, 9, 19, and 114 seconds. This experimental program was successful in generating velocity and pressure gradient data for the flow field around the submerged nose nozzle of the Space Shuttle SRM at various burn times and gimbal angles. The nature of the flow field adjacent to the nozzle/case joint was determined with oil droplet streaks, and the velocity and pressure gradients were quantified with pitot probes and wall static pressure measurements. The data was applied to the full scale SRM thru

  15. Improved superheater component longevity by steam flow redistribution. Final report

    SciTech Connect

    Hara, K.; Lee, C.; Moser, R.; Rettig, T.; Clark, K.

    1992-12-01

    A common problem in fossil fuel boilers is excessive tube metal temperatures in local regions of superheater and reheater tube banks. The resulting increased high temperature creep rates in the tubes in each local hot region lead to unacceptably high tube failure rates at these locations. In this situation, the utility often decides that the entire superheater must be replaced when, in fact, only a small percentage of the tubes is at end of life. The local hot regions are generally caused by heat flux nonuniformities on the fireside and also by steam flow nonuniformities. In this work, a solution to this problem is demonstrated which utilizes the concept of steam flow redistribution. The tube-to-tube steam flowrates are increased for hot tubes and decreased for cold tubes, subject to the constraint that total steam flowrate remains unaffected. The flowrate changes are accomplished by installing steam flow controllers in individual tubes to modify the flow resistance in each tube in a predictable manner. A guideline has been developed for designing, installing, and testing a pattern of steam flow controllers which optimizes the steam flow redistribution for a specific boiler. The optimum design achieves the maximum economic benefit by reducing the future tube failure rate and extending the life of the superheater. The general guideline, engineering design, economic assessment, and field testing procedures are described in detail. The general guideline and specific engineering procedures have been demonstrated for a site specific case, the superheater at San Diego Gas & Electric Company`s South Bay Plant, Unit 1. This study and demonstration provide both initial validation of the concept of steam flow redistribution to improve superheater longevity and incentive to apply the concept to other units.

  16. Improved superheater component longevity by steam flow redistribution

    SciTech Connect

    Hara, K.; Lee, C.; Moser, R.; Rettig, T.; Clark, K. )

    1992-12-01

    A common problem in fossil fuel boilers is excessive tube metal temperatures in local regions of superheater and reheater tube banks. The resulting increased high temperature creep rates in the tubes in each local hot region lead to unacceptably high tube failure rates at these locations. In this situation, the utility often decides that the entire superheater must be replaced when, in fact, only a small percentage of the tubes is at end of life. The local hot regions are generally caused by heat flux nonuniformities on the fireside and also by steam flow nonuniformities. In this work, a solution to this problem is demonstrated which utilizes the concept of steam flow redistribution. The tube-to-tube steam flowrates are increased for hot tubes and decreased for cold tubes, subject to the constraint that total steam flowrate remains unaffected. The flowrate changes are accomplished by installing steam flow controllers in individual tubes to modify the flow resistance in each tube in a predictable manner. A guideline has been developed for designing, installing, and testing a pattern of steam flow controllers which optimizes the steam flow redistribution for a specific boiler. The optimum design achieves the maximum economic benefit by reducing the future tube failure rate and extending the life of the superheater. The general guideline, engineering design, economic assessment, and field testing procedures are described in detail. The general guideline and specific engineering procedures have been demonstrated for a site specific case, the superheater at San Diego Gas Electric Company's South Bay Plant, Unit 1. This study and demonstration provide both initial validation of the concept of steam flow redistribution to improve superheater longevity and incentive to apply the concept to other units.

  17. Freezing Characteristics of Molding Sand with Water by Cold Air Flow for Freeze Mold

    NASA Astrophysics Data System (ADS)

    Horibe, Akihiko; Inaba, Hideo; Haruki, Naoto; Miyagawa, Yasunori

    This paper reports the freezing characteristics of sand molded with "the freeze mold method". The freeze mold method is the casting process where little water is added to cast sand then they are frozen and become harden as a mold. Instead of using organic hardener, this molding technology possibly reduces resources and environment loading. We aimed at the practical application of the freeze mold method and chose cold airflow as the medium taking heat away from the mold. At first the sand with water was filled into a rectangular container that is the test section. Then cold air flowed into the container. Consequently, the mold was cooled and frozen by the cold airflow. The freezing behavior of the sample by cold airflow was investigated experimentally under the conditions of added water amount, superficial velocity, inflow air temperature and fixed bed height. As a result, the freezing completion time becomes long as the added water amount increases. However, an increase in the added water amount doesn't influence the pressure loss of the test section so much. Moreover, the empirical equation was derived to predict the freezing completion time.

  18. Improvement of the U.S. Army Intermediate Cold Wet Boot

    DTIC Science & Technology

    2002-04-01

    thermal comfort of the human foot during exposure to cold ambient temperatures. 33-5 Figure 4. Photograph showing human volunteers during the 1990 ICWB...boot indicating that it would provide an increased level of thermal comfort . The then-current U.S. Army Intermediate Cold-Wet Boot, 34 33 32 31 E 30 E...has been recommended that the U.S. Army continue to evaluate future improvements in these materials designed to increase individual thermal comfort and

  19. Stereomicroscopic imaging technique for the quantification of cold flow in drug-in-adhesive type of transdermal drug delivery systems.

    PubMed

    Krishnaiah, Yellela S R; Katragadda, Usha; Khan, Mansoor A

    2014-05-01

    Cold flow is a phenomenon occurring in drug-in-adhesive type of transdermal drug delivery systems (DIA-TDDS) because of the migration of DIA coat beyond the edge. Excessive cold flow can affect their therapeutic effectiveness, make removal of DIA-TDDS difficult from the pouch, and potentially decrease available dose if any drug remains adhered to pouch. There are no compendial or noncompendial methods available for quantification of this critical quality attribute. The objective was to develop a method for quantification of cold flow using stereomicroscopic imaging technique. Cold flow was induced by applying 1 kg force on punched-out samples of marketed estradiol DIA-TDDS (model product) stored at 25°C, 32°C, and 40°C/60% relative humidity (RH) for 1, 2, or 3 days. At the end of testing period, dimensional change in the area of DIA-TDDS samples was measured using image analysis software, and expressed as percent of cold flow. The percent of cold flow significantly decreased (p < 0.001) with increase in size of punched-out DIA-TDDS samples and increased (p < 0.001) with increase in cold flow induction temperature and time. This first ever report suggests that dimensional change in the area of punched-out samples stored at 32°C/60%RH for 2 days applied with 1 kg force could be used for quantification of cold flow in DIA-TDDS. © 2014 Wiley Periodicals, Inc. and the American Pharmacists Association.

  20. OBSERVING THE END OF COLD FLOW ACCRETION USING HALO ABSORPTION SYSTEMS

    SciTech Connect

    Stewart, Kyle R.; Kaufmann, Tobias; Bullock, James S.; Barton, Elizabeth J.; Maller, Ariyeh H.; Diemand, Juerg; Wadsley, James

    2011-07-01

    We use cosmological smoothed particle hydrodynamic simulations to study the cool, accreted gas in two Milky Way size galaxies through cosmic time to z = 0. We find that gas from mergers and cold flow accretion results in significant amounts of cool gas in galaxy halos. This cool circum-galactic component drops precipitously once the galaxies cross the critical mass to form stable shocks, M{sub vir} = M{sub sh} {approx} 10{sup 12} M{sub sun}. Before reaching M{sub sh}, the galaxies experience cold mode accretion (T < 10{sup 5} K) and show moderately high covering fractions in accreted gas: f{sub c} {approx} 30%-50% for R < 50 comoving kpc and N{sub Hi}>10{sup 16} cm{sup -2}. These values are considerably lower than observed covering fractions, suggesting that outflowing gas (not included here) is important in simulating galaxies with realistic gaseous halos. Within {approx}500 Myr of crossing the M{sub sh} threshold, each galaxy transitions to hot mode gas accretion, and f{sub c} drops to {approx}5%. The sharp transition in covering fraction is primarily a function of halo mass, not redshift. This signature should be detectable in absorption system studies that target galaxies of varying host mass, and may provide a direct observational tracer of the transition from cold flow accretion to hot mode accretion in galaxies.

  1. The effects of magnetic fields in cold clouds in cooling flows

    NASA Astrophysics Data System (ADS)

    Friaça, A. C. S.; Jafelice, L. C.

    1999-01-01

    Large masses of absorbing material are inferred to exist in cooling flows in clusters of galaxies from the excess X-ray absorption in the spectra of some X-ray clusters. The absorbing material is probably in the form of cold clouds pressure-confined by the surrounding, hot, X-ray-emitting gas. The cold clouds could remain relatively static until they are destroyed by evaporation or ablation, or give rise to star formation. If the final fate of the clouds is stars, the initial mass function (IMF) of the stars formed over the whole cooling-flow region (r~ 100 kpc) should be biased to low masses, to avoid a very luminous, blue halo for the central galaxy of the cooling flow. However, there is evidence for bright star formation in the innermost (r<= 10 kpc) regions of some cooling flows, and, therefore, the biasing of the IMF towards low masses should not occur or should be less important at smaller radii. The consideration of magnetic fields may shed light on these two points. If magnetic fields are present, the magnetic critical mass should be considered, besides the Jeans mass, in establishing a natural mass-scale for star formation. When this new mass-scale is taken into account, we obtain the right variation of the biasing of the IMF with the radius in addition to inhibition of high-mass star formation at large radii. We also demonstrate that magnetic reconnection is a more efficient mechanism than ambipolar diffusion to remove magnetic fields in cold clouds.

  2. Improved bonding strength of bioactive cermet Cold Gas Spray coatings.

    PubMed

    Gardon, M; Concustell, A; Dosta, S; Cinca, N; Cano, I G; Guilemany, J M

    2014-12-01

    The fabrication of cermet biocompatible coatings by means Cold Gas Spray (CGS) provides prosthesis with outstanding mechanical properties and the required composition for enhancing the bioactivity of prosthetic materials. In this study, hydroxyapatite/Titanium coatings were deposited by means of CGS technology onto titanium alloy substrates with the aim of building-up well-bonded homogeneous coatings. Powders were blended in different percentages and sprayed; as long as the amount of hydroxyapatite in the feedstock increased, the quality of the coating was reduced. Besides, the relation between the particle size distribution of ceramic and metallic particles is of significant consideration. Plastic deformation of titanium particles at the impact eased the anchoring of hard hydroxyapatite particles present at the top surface of the coating, which assures the looked-for interaction with the cells. Coatings were immersed in Hank's solution for 1, 4 and 7 days; bonding strength value was above 60 MPa even after 7 days, which enhances common results of HAp coatings obtained by conventional thermal spray technologies.

  3. Cold pressor test improves fear extinction in healthy men.

    PubMed

    Antov, Martin I; Melicherová, Ursula; Stockhorst, Ursula

    2015-04-01

    Fear extinction is an important paradigm to study the neural basis of anxiety and trauma- and stressor-related disorders and for modeling features of extinction learning and exposure-based psychotherapy. To date the effects of acute stress on extinction learning in humans are not well understood. Models of stress effects on emotional memory suggest that learning during the so-called first wave of the stress response will be enhanced. The first wave includes (among others) increases of noradrenaline in the brain and increased sympathetic tone, adrenaline and noradrenaline in the periphery while the second wave includes genomic glucocorticoid-actions. The cold pressor test (CPT) is a valid way to induce the first wave of the stress response. We thus hypothesized that the CPT will facilitate extinction. In a 2-day fear-conditioning procedure with 40 healthy men, using differential skin conductance responses as a measure of conditioned fear, we placed the CPT versus a control procedure prior to extinction training on Day 1. We tested for extinction learning on Day 1 and extinction retrieval on Day 2. During extinction training (Day 1) only the CPT-group showed a significant reduction in differential responding. This was still evident on Day 2, where the CPT group had less differential responding during early trials (retrieval) and a higher extinction retention index. This is the first human study to show that a simple procedure, triggering the first-wave stress response--the CPT--can effectively enhance fear extinction in humans.

  4. Sugar feeding improves survival of nondiapausing cold-stored Culex pipiens.

    PubMed

    Rinehart, Joseph P; Yocum, George D; Robich, Rebecca M

    2012-11-01

    The continuous culture of mosquitoes is a costly endeavor for vector biology laboratories. In addition to the resources that must be committed to colony maintenance, biological costs, including genetic drift and accidental colony loss, also can occur. Although alternatives do exist, their application to mosquitoes is limited. Mosquito cryopreservation remains elusive, and many important species lack a well-defined diapause. Previously, we demonstrated that cold storing nondiapausing mated adult females of the northern house mosquito, Culex pipiens L. resulted in a nearly four-fold increase in longevity when measured at the LT50, allowing for cold storage for up to 10 wk. In the current study, we used sugar feeding during cold storage to significantly improve cold storage longevity. At 6 degrees C, the LT50 of cold stored females was 23 wk, and 100% mortality was not realized until 43 wk. Cold-stored females did exhibit reduced fecundity, but egg production returned to normal levels within two generations. These results suggest that cold storage without diapause induction is a viable option for Cx. pipiens, and with the addition of sugar feeding, a colony could be maintained with less than two generations per year.

  5. Flow and cold heat-storage characteristics of phase-change emulsion in a coiled double-tube heat exchanger

    SciTech Connect

    Inaba, H.; Morita, S.

    1995-05-01

    This paper dealt with the flow and cold heat-storage characteristics of the oil (tetradecane, C{sub 14}H{sub 30}, freezing point 278.9 K)/water emulsion as a latent heat-storage material having a low melting point. A coiled double-tube heat exchanger was used for the cold heat storage experiment. The pressure drop, the heat transfer coefficient, and the finishing time of cold heat storage in the coiled tube were measured as experimental parameters. It was understood that the flow behavior of the emulsion as a non-Newtonian fluid had an important role in the present cold heat storage. The useful nondimensional correlation equations for the additional pressure loss coefficient, the heat transfer coefficient, and the cold heat storage time were derived in terms of modified Dean number and heat capacity ratio. 11 refs., 13 figs., 1 tab.

  6. Comparative photosynthetic and metabolic analyses reveal mechanism of improved cold stress tolerance in bermudagrass by exogenous melatonin.

    PubMed

    Hu, Zhengrong; Fan, Jibiao; Xie, Yan; Amombo, Erick; Liu, Ao; Gitau, Margaret Mukami; Khaldun, A B M; Chen, Liang; Fu, Jinmin

    2016-03-01

    Melatonin (N-acetyl-5-methoxytryptamine) has been reported to participate in plant development and abiotic stress responses. The main objective of this study was to investigate the role of melatonin in the cold-sensitive (S) and the cold-tolerant (T) bermudagrass genotypes' response to cold stress. The genotypes were treated with 100 μM melatonin and exposed to 4 °C temperature for 3 days. In both genotypes, cold stress increased the endogenous melatonin levels, and more prominently in T than S. Physiological responses indicated that exogenous melatonin triggered antioxidant activities in both genotypes, while it alleviated cell damage in the T genotype response to cold stress. Melatonin treatment under cold stress increased fluorescence curve levels for both genotypes, and higher in T than S genotypes. In both genotypes, the alterations in photosynthetic fluorescence parameters after melatonin treatment highlighted the participation of melatonin in improving photosystem response to cold stress, particularly for the cold-tolerant genotype. The metabolic analyses revealed the alterations of 44 cold-responsive metabolites in the two genotypes, mainly including carbohydrates, organic acids and amino acids. After exogenous melatonin treatment under cold condition, there was high accumulation of metabolites in the cold-tolerant regimes than their cold-sensitive counterparts. Collectively, the present study revealed differential modulations of melatonin between the cold-sensitive and the cold-tolerant genotypes in response to cold stress. This was mainly by impacting antioxidant system, photosystem II, as well as metabolic homeostasis.

  7. Effect of cold air inhalation and isometric exercise on coronary blood flow and myocardial function in humans

    PubMed Central

    Muller, Matthew D.; Gao, Zhaohui; Drew, Rachel C.; Herr, Michael D.; Leuenberger, Urs A.

    2011-01-01

    The effects of cold air inhalation and isometric exercise on coronary blood flow are currently unknown, despite the fact that both cold air and acute exertion trigger angina in clinical populations. In this study, we used transthoracic Doppler echocardiography to measure coronary blood flow velocity (CBV; left anterior descending coronary artery) and myocardial function during cold air inhalation and handgrip exercise. Ten young healthy subjects underwent the following protocols: 5 min of inhaling cold air (cold air protocol), 5 min of inhaling thermoneutral air (sham protocol), 2 min of isometric handgrip at 30% of maximal voluntary contraction (grip protocol), and 5 min of isometric handgrip at 30% maximal voluntary contraction while breathing cold air (cold + grip protocol). Heart rate, blood pressure, inspired air temperature, CBV, myocardial function (tissue Doppler imaging), O2 saturation, and pulmonary function were measured. The rate-pressure product (RPP) was used as an index of myocardial O2 demand, whereas CBV was used as an index of myocardial O2 supply. Compared with the sham protocol, the cold air protocol caused a significantly higher RPP, but there was a significant reduction in CBV. The cold + grip protocol caused a significantly greater increase in RPP compared with the grip protocol (P = 0.045), but the increase in CBV was significantly less (P = 0.039). However, myocardial function was not impaired during the cold + grip protocol relative to the grip protocol alone. Collectively, these data indicate that there is a supply-demand mismatch in the coronary vascular bed when cold ambient air is breathed during acute exertion but myocardial function is preserved, suggesting an adequate redistribution of blood flow. PMID:21940852

  8. Effect of cold air inhalation and isometric exercise on coronary blood flow and myocardial function in humans.

    PubMed

    Muller, Matthew D; Gao, Zhaohui; Drew, Rachel C; Herr, Michael D; Leuenberger, Urs A; Sinoway, Lawrence I

    2011-12-01

    The effects of cold air inhalation and isometric exercise on coronary blood flow are currently unknown, despite the fact that both cold air and acute exertion trigger angina in clinical populations. In this study, we used transthoracic Doppler echocardiography to measure coronary blood flow velocity (CBV; left anterior descending coronary artery) and myocardial function during cold air inhalation and handgrip exercise. Ten young healthy subjects underwent the following protocols: 5 min of inhaling cold air (cold air protocol), 5 min of inhaling thermoneutral air (sham protocol), 2 min of isometric handgrip at 30% of maximal voluntary contraction (grip protocol), and 5 min of isometric handgrip at 30% maximal voluntary contraction while breathing cold air (cold + grip protocol). Heart rate, blood pressure, inspired air temperature, CBV, myocardial function (tissue Doppler imaging), O(2) saturation, and pulmonary function were measured. The rate-pressure product (RPP) was used as an index of myocardial O(2) demand, whereas CBV was used as an index of myocardial O(2) supply. Compared with the sham protocol, the cold air protocol caused a significantly higher RPP, but there was a significant reduction in CBV. The cold + grip protocol caused a significantly greater increase in RPP compared with the grip protocol (P = 0.045), but the increase in CBV was significantly less (P = 0.039). However, myocardial function was not impaired during the cold + grip protocol relative to the grip protocol alone. Collectively, these data indicate that there is a supply-demand mismatch in the coronary vascular bed when cold ambient air is breathed during acute exertion but myocardial function is preserved, suggesting an adequate redistribution of blood flow.

  9. Experimental Investigation of the Mixing Effects of Cold Flow in Plasma-Jets

    NASA Astrophysics Data System (ADS)

    Purpura, C.; de Filippis, F.; Esposito, A.; Renis, R.

    2005-02-01

    The Plasma Wind Tunnel (PWT) SCIROCCO located at CIRA (Capua, Italy), is a hypersonic facility where the atmospheric conditions around the space vehicles during re-entry are reproduced. The Validation Phase of the SCIROCCO facility is at present on going. Here, it is important to investigate the flow uniformity at the nozzle exit by injecting transversal cold flow. Since it is very difficult to carry out this investigation in SCIROCCO, it has been developed in the Small Plasma Entry Simulator (SPES) at the University of Naples, because of its lower power and scale. In the present paper, the results obtained in the SPES facility about the mixing effects on the flow uniformity are shown and a comparison with the results obtained in the SCIROCCO facility during the development of a preliminary mixing test campaign.

  10. Intermittent cold exposure improves glucose homeostasis associated with brown and white adipose tissues in mice

    PubMed Central

    Wang, Tse-Yao; Liu, Cuiqing; Wang, Aixia; Sun, Qinghua

    2015-01-01

    Aims The discovery of different shades of fat has been implicated in the pathogenesis of obesity-related metabolic disorders. However, the effects of early and intermittent exposure to cold temperature on systemic metabolic changes in adult life remain unclear. Main methods To elucidate the impact of cold temperature exposure on metabolic function of adipose tissues, we investigated the glucose homeostasis, activation of brown adipose tissue (BAT) and “browning” of white adipose tissue (WAT) in mice in response to intermittent cold exposure. Mice were exposed to 4 °C, 2 hours per day and 5 days per week, for 14 weeks. Glucose homeostasis was tested via intraperitoneal glucose tolerance test and insulin tolerance test; body fat mass was evaluated using in vivo magnetic resonance imaging; BAT activity was detected primarily by positron emission tomography/computed tomography; and WAT “browning” was evaluated using immunohistochemistry. Key findings Our results showed that 14-week cold exposure improved glucose tolerance and enhanced insulin sensitivity, reduced the relative weights of epididymal and retroperitoneal WAT, increased expressions of UCP1 and PGC1α in subcutaneous adipose tissue. Significance Intermittent exposure to cold temperature in early life may improve systemic glucose homeostasis and induce WAT “browning”, suggesting that ambient cold temperature exposure may serve as a promising intervention to metabolic disorders. PMID:26281919

  11. Improved modeling techniques for turbomachinery flow fields

    SciTech Connect

    Lakshminarayana, B.; Fagan, J.R. Jr.

    1995-10-01

    This program has the objective of developing an improved methodology for modeling turbomachinery flow fields, including the prediction of losses and efficiency. Specifically, the program addresses the treatment of the mixing stress tensor terms attributed to deterministic flow field mechanisms required in steady-state Computational Fluid Dynamic (CFD) models for turbo-machinery flow fields. These mixing stress tensors arise due to spatial and temporal fluctuations (in an absolute frame of reference) caused by rotor-stator interaction due to various blade rows and by blade-to-blade variation of flow properties. These tasks include the acquisition of previously unavailable experimental data in a high-speed turbomachinery environment, the use of advanced techniques to analyze the data, and the development of a methodology to treat the deterministic component of the mixing stress tensor. Penn State will lead the effort to make direct measurements of the momentum and thermal mixing stress tensors in high-speed multistage compressor flow field in the turbomachinery laboratory at Penn State. They will also process the data by both conventional and conditional spectrum analysis to derive momentum and thermal mixing stress tensors due to blade-to-blade periodic and aperiodic components, revolution periodic and aperiodic components arising from various blade rows and non-deterministic (which includes random components) correlations. The modeling results from this program will be publicly available and generally applicable to steady-state Navier-Stokes solvers used for turbomachinery component (compressor or turbine) flow field predictions. These models will lead to improved methodology, including loss and efficiency prediction, for the design of high-efficiency turbomachinery and drastically reduce the time required for the design and development cycle of turbomachinery.

  12. Method and apparatus for cold gas reinjection in through-flow and reverse-flow wave rotors

    NASA Technical Reports Server (NTRS)

    Nalim, M. Razi (Inventor); Paxson, Daniel E. (Inventor)

    1999-01-01

    A method and apparatus for cold gas reinjection in through-flow and reverse-flow wave rotors having a plurality of channels formed around a periphery thereof. A first port injects a supply of cool air into the channels. A second port allows the supply of cool air to exit the channels and flow to a combustor. A third port injects a supply of hot gas from the combustor into the channels. A fourth port allows the supply of hot gas to exit the channels and flow to a turbine. A diverting port and a reinjection port are connected to the second and third ports, respectively. The diverting port diverts a portion of the cool air exiting through the second port as reinjection air. The diverting port is fluidly connected to the reinjection port which reinjects the reinjection air back into the channels. The reinjection air evacuates the channels of the hot gas resident therein and cools the channel walls, a pair of end walls of the rotor, ducts communicating with the rotor and subsequent downstream components. In a second embodiment, the second port receives all of the cool air exiting the channels and the diverting port diverts a portion of the cool air just prior to the cool air flowing to the combustor.

  13. How enhanced molecular ions in Cold EI improve compound identification by the NIST library.

    PubMed

    Alon, Tal; Amirav, Aviv

    2015-12-15

    Library-based compound identification with electron ionization (EI) mass spectrometry (MS) is a well-established identification method which provides the names and structures of sample compounds up to the isomer level. The library (such as NIST) search algorithm compares different EI mass spectra in the library's database with the measured EI mass spectrum, assigning each of them a similarity score called 'Match' and an overall identification probability. Cold EI, electron ionization of vibrationally cold molecules in supersonic molecular beams, provides mass spectra with all the standard EI fragment ions combined with enhanced Molecular Ions and high-mass fragments. As a result, Cold EI mass spectra differ from those provided by standard EI and tend to yield lower matching scores. However, in most cases, library identification actually improves with Cold EI, as library identification probabilities for the correct library mass spectra increase, despite the lower matching factors. This research examined the way that enhanced molecular ion abundances affect library identification probability and the way that Cold EI mass spectra, which include enhanced molecular ions and high-mass fragment ions, typically improve library identification results. It involved several computer simulations, which incrementally modified the relative abundances of the various ions and analyzed the resulting mass spectra. The simulation results support previous measurements, showing that while enhanced molecular ion and high-mass fragment ions lower the matching factor of the correct library compound, the matching factors of the incorrect library candidates are lowered even more, resulting in a rise in the identification probability for the correct compound. This behavior which was previously observed by analyzing Cold EI mass spectra can be explained by the fact that high-mass ions, and especially the molecular ion, characterize a compound more than low-mass ions and therefore carries more

  14. Effect of cold water immersion on repeated cycling performance and limb blood flow.

    PubMed

    Vaile, J; O'Hagan, C; Stefanovic, B; Walker, M; Gill, N; Askew, C D

    2011-08-01

    The purpose of the present study was to compare the effects of cold water immersion (CWI) and active recovery (ACT) on resting limb blood flow, rectal temperature and repeated cycling performance in the heat. Ten subjects completed two testing sessions separated by 1 week; each trial consisted of an initial all-out 35-min exercise bout, one of two 15-min recovery interventions (randomised: CWI or ACT), followed by a 40-min passive recovery period before repeating the 35-min exercise bout. Performance was measured as the change in total work completed during the exercise bouts. Resting limb blood flow, heart rate, rectal temperature and blood lactate were recorded throughout the testing sessions. There was a significant decline in performance after ACT (mean (SD) -1.81% (1.05%)) compared with CWI where performance remained unchanged (0.10% (0.71%)). Rectal temperature was reduced after CWI (36.8°C (1.0°C)) compared with ACT (38.3°C (0.4°C)), as was blood flow to the arms (CWI 3.64 (1.47) ml/100 ml/min; ACT 16.85 (3.57) ml/100 ml/min) and legs (CW 4.83 (2.49) ml/100 ml/min; ACT 4.83 (2.49) ml/100 ml/min). Leg blood flow at the end of the second exercise bout was not different between the active (15.25 (4.33) ml/100 ml/min) and cold trials (14.99 (4.96) ml/100 ml/min), whereas rectal temperature (CWI 38.1°C (0.3°C); ACT 38.8°C (0.2°C)) and arm blood flow (CWI 20.55 (3.78) ml/100 ml/min; ACT 23.83 (5.32) ml/100 ml/min) remained depressed until the end of the cold trial. These findings indicate that CWI is an effective intervention for maintaining repeat cycling performance in the heat and this performance benefit is associated with alterations in core temperature and limb blood flow.

  15. Inflow velocities of cold flows streaming into massive galaxies at high redshifts

    NASA Astrophysics Data System (ADS)

    Goerdt, Tobias; Ceverino, Daniel

    2015-07-01

    We study the velocities of the accretion along streams from the cosmic web into massive galaxies at high redshift with the help of three different suites of AMR hydrodynamical cosmological simulations. The results are compared to free-fall velocities and to the sound speeds of the hot ambient medium. The sound speed of the hot ambient medium is calculated using two different methods to determine the medium's temperature. We find that the simulated cold stream velocities are in violent disagreement with the corresponding free-fall profiles. The sound speed is a better albeit not always correct description of the cold flows' velocity. Using these calculations as a first order approximation for the gas inflow velocities vinflow = 0.9 vvir is given. We conclude from the hydrodynamical simulations as our main result that the velocity profiles for the cold streams are constant with radius. These constant inflow velocities seem to have a `parabola-like' dependency on the host halo mass in units of the virial velocity that peaks at Mvir = 1012 M⊙ and we also propose that the best-fitting functional form for the dependency of the inflow velocity on the redshift is a square root power-law relation: v_inflow ∝ √{z + 1} v_vir.

  16. High-z QSO Absorption Systems: Metal-Poor Cold Flows and Mg II Absorber Host Galaxies

    NASA Astrophysics Data System (ADS)

    Cooper, Thomas; Simcoe, R. A.; Cooksey, K.; O'Meara, J.

    2014-01-01

    Cosmological simulations have suggested a new model for gas accretion in young galaxies, in which baryons flow into the star-forming disk along filamentary streams without shock heating at the dark matter halo virial radius. Observationally, these cold flows manifest as Lyman Limit Systems with low heavy element abundances. To search for cold flows in the early Universe, we have obtained echellette-resolution spectra of an HI-selected sample of LLS at z>3.5 from the Sloan Digital Sky Survey. The sightlines were selected to exhibit no heavy element absorption at the resolution afforded by SDSS, and the higher resolution data provides metallicity measurements precise enough to determine if they exhibit cold flow accretion characteristics. In a parallel program, we use the Magellan Telescopes and HST/WFC-3 to investigate the connection between Mg II absorbers and proximate galaxies at 3, extending fruitful studies of the circumgalactic medium to larger redshift.

  17. Single element injector cold flow testing for STME swirl coaxial injector element design

    NASA Technical Reports Server (NTRS)

    Hulka, J.; Schneider, J. A.

    1993-01-01

    An oxidizer-swirled coaxial element injector is being investigated for application in the Space Transportation Main Engine (STME). Single element cold flow experiments were conducted to provide characterization of the STME injector element for future analysis, design, and optimization. All tests were conducted to quiescent, ambient backpressure conditions. Spray angle, circumferential spray uniformity, dropsize, and dropsize distribution were measured in water-only and water/nitrogen flows. Rupe mixing efficiency was measured using water/sucrose solution flows with a large grid patternator for simple comparative evaluation of mixing. Factorial designs of experiment were used for statistical evaluation of injector geometrical design features and propellant flow conditions on mixing and atomization. Increasing the free swirl angle of the liquid oxidizer had the greatest influence on increasing the mixing efficiency. The addition of gas assistance had the most significant effect on reducing oxidizer droplet size parameters and increasing droplet size distribution. Increasing the oxidizer injection velocity had the greatest influence for reducing oxidizer droplet size parameters and increasing size distribution for non-gas assisted flows. Single element and multi-element subscale hot fire testing are recommended to verify optimized designs before committing to the STME design.

  18. The effect of local cold application on intramuscular blood flow at rest and after running.

    PubMed

    Thorsson, O; Lilja, B; Ahlgren, L; Hemdal, B; Westlin, N

    1985-12-01

    Local blood flow was measured with 133Xe clearance technique in eight male distance runners, where one leg was cooled for 20 min by applying two "instant cold packs" on the quadriceps muscle. An initial cooling period after resting was followed by a second cooling period 10 min after running. Skin temperature was maximally reduced after 4.5 min of cooling, both at rest and after running, by 15 degrees C and 14.9 degrees C, respectively. During the first 5 min of cooling no reduction of blood flow was seen. After 10 min of cooling blood flow was significantly reduced in the cooled compared to the control leg by 49% (P less than 0.05) after resting and 34% (P less than 0.05) after running. A maximum reduction of blood flow by 66 and 69% (P less than 0.01), respectively, was seen 10 min after the cooling period. In the event of an acute injury, this delayed reaction of cryotherapy on intramuscular blood flow should be carefully considered.

  19. Single element injector cold flow testing for STME swirl coaxial injector element design

    NASA Technical Reports Server (NTRS)

    Hulka, J.; Schneider, J. A.

    1993-01-01

    An oxidizer-swirled coaxial element injector is being investigated for application in the Space Transportation Main Engine (STME). Single element cold flow experiments were conducted to provide characterization of the STME injector element for future analysis, design, and optimization. All tests were conducted to quiescent, ambient backpressure conditions. Spray angle, circumferential spray uniformity, dropsize, and dropsize distribution were measured in water-only and water/nitrogen flows. Rupe mixing efficiency was measured using water/sucrose solution flows with a large grid patternator for simple comparative evaluation of mixing. Factorial designs of experiment were used for statistical evaluation of injector geometrical design features and propellant flow conditions on mixing and atomization. Increasing the free swirl angle of the liquid oxidizer had the greatest influence on increasing the mixing efficiency. The addition of gas assistance had the most significant effect on reducing oxidizer droplet size parameters and increasing droplet size distribution. Increasing the oxidizer injection velocity had the greatest influence for reducing oxidizer droplet size parameters and increasing size distribution for non-gas assisted flows. Single element and multi-element subscale hot fire testing are recommended to verify optimized designs before committing to the STME design.

  20. Electromagnetic and Thermal-flow Modeling of a Cold-Wall Crucible Induction Melter

    SciTech Connect

    Fort, James A.; Garnich, Mark R.; Klymyshyn, Nicholas A.

    2005-02-01

    An approach for modeling cold-wall crucible induction melters is described. Materials in the melt and melter are non-ferromagnetic. In contrast to other modeling works reported in the literature, the numerical models utilize commercial codes. The ANSYS finite element code is employed for electromagnetic field simulations and the STAR-CD finite volume code for thermal-flow calculations. Results from the electromagnetic calculations in the form of local Joule heat and Lorentz force distributions are included as loads in the thermal-flow analysis. This loosely-coupled approach is made possible by the small variation in temperature and, consequently, small variation in electrical properties across the melt as well as the quasi-steady state nature of the thermal flow calculations. A three dimensional finite element grid for electromagnetic calculations is adapted to a similar axisymmetric finite volume grid for data transfer to the thermal-flow model. Results from the electromagnetic model compare well with operational data from a 175 mm diameter melter. Results from the thermal-flow simulation provide insight toward molten metal circulation patterns, temperature variations, and velocity magnitudes. Initial results are included for a model that simulates the formation of a solid (skull) layer on the crucible base and wall. Overall, the modeling approach is shown to produce useful results relating operational parameters to the physics of steady state melter operation.

  1. NASA Ares I Launch Vehicle First Stage Roll Control System Cold Flow Development Test Program Overview

    NASA Technical Reports Server (NTRS)

    Butt, Adam; Popp, Christopher G.; Holt, Kimberly A.; Pitts, Hank M.

    2010-01-01

    The Ares I launch vehicle is the selected design, chosen to return humans to the moon, Mars, and beyond. It is configured in two inline stages: the First Stage is a Space Shuttle derived five-segment Solid Rocket Booster and the Upper Stage is powered by a Saturn V derived J-2X engine. During launch, roll control for the First Stage (FS) is handled by a dedicated Roll Control System (RoCS) located on the connecting Interstage. That system will provide the Ares I with the ability to counteract induced roll torque while any induced yaw or pitch moments are handled by vectoring of the booster nozzle. This paper provides an overview of NASA s Ares I FS RoCS cold flow development test program including detailed test objectives, types of tests run to meet those objectives, an overview of the results, and applicable lessons learned. The test article was built and tested at the NASA Marshall Space Flight Center in Huntsville, AL. The FS RoCS System Development Test Article (SDTA) is a full scale, flight representative water flow test article whose primary objective was to obtain fluid system performance data to evaluate integrated system level performance characteristics and verify analytical models. Development testing and model correlation was deemed necessary as there is little historical precedent for similar large flow, pulsing systems such as the FS RoCS. The cold flow development test program consisted of flight-similar tanks, pressure regulators, and thruster valves, as well as plumbing simulating flight geometries, combined with other facility grade components and structure. Orifices downstream of the thruster valves were used to simulate the pressure drop through the thrusters. Additional primary objectives of this test program were to: evaluate system surge pressure (waterhammer) characteristics due to thruster valve operation over a range of mission duty cycles at various feed system pressures, evaluate temperature transients and heat transfer in the

  2. Pressure Drop in Cold Water Flow in Beds Packed with Several Kinds of Crushed Ice.

    NASA Astrophysics Data System (ADS)

    Yanadori, Michio; Ohira, Akiyoshi

    This paper deals with the pressure drop in cold water flow in the beds packed with crushed ice. 1n each case, ice-packed beds were filled with sevral kinds of crushed ice, and friction-loss coefficients were examined. The following results were obtained. (1) The friction factor of rectangular-type ice-packed beds is smaller than that of ideal sphere beds by about 1/4 to 1/2. (2) The friction factor of small-stone-type ice-packed beds is about twice as large as that of ideal sphere beds. (3) It is difficult to compare the flow model of water in restricted channel of particle-type ice-packed beds with that of ideal packed beds.

  3. Large eddy simulation of mixing between hot and cold sodium flows - comparison with experiments

    SciTech Connect

    Simoneau, J.P.; Noe, H.; Menant, B.

    1995-09-01

    The large eddy simulation is becoming a potential powerful tool for the calculation of turbulent flows. In nuclear liquid metal cooled fast reactors, the knowledge of the turbulence characteristics is of great interest for the prediction and the analysis of thermal stripping phenomena. The objective of this paper is to give a contribution in the evaluation of the large eddy simulation technique is an individual case. The problem chosen is the case of the mixing between hot and cold sodium flows. The computations are compared with available sodium tests. This study shows acceptable qualitative results but the simple model used is not able to predict the turbulence characteristics. More complex models including larger domains around the fluctuating zone and fluctuating boundary conditions could be necessary. Validation works are continuing.

  4. Cold Flow Testing for Liquid Propellant Rocket Injector Scaling and Throttling

    NASA Technical Reports Server (NTRS)

    Kenny, Jeremy R.; Moser, Marlow D.; Hulka, James; Jones, Gregg

    2006-01-01

    Scaling and throttling of combustion devices are important capabilities to demonstrate in development of liquid rocket engines for NASA's Space Exploration Mission. Scaling provides the ability to design new injectors and injection elements with predictable performance on the basis of test experience with existing injectors and elements, and could be a key aspect of future development programs. Throttling is the reduction of thrust with fixed designs and is a critical requirement in lunar and other planetary landing missions. A task in the Constellation University Institutes Program (CUIP) has been designed to evaluate spray characteristics when liquid propellant rocket engine injectors are scaled and throttled. The specific objectives of the present study are to characterize injection and primary atomization using cold flow simulations of the reacting sprays. These simulations can provide relevant information because the injection and primary atomization are believed to be the spray processes least affected by the propellant reaction. Cold flow studies also provide acceptable test conditions for a university environment. Three geometric scales - 1/4- scale, 1/2-scale, and full-scale - of two different injector element types - swirl coaxial and shear coaxial - will be designed, fabricated, and tested. A literature review is currently being conducted to revisit and compile the previous scaling documentation. Because it is simple to perform, throttling will also be examined in the present work by measuring primary atomization characteristics as the mass flow rate and pressure drop of the six injector element concepts are reduced, with corresponding changes in chamber backpressure. Simulants will include water and gaseous nitrogen, and an optically accessible chamber will be used for visual and laser-based diagnostics. The chamber will include curtain flow capability to repress recirculation, and additional gas injection to provide independent control of the

  5. Modifying shale oil to improve flow characteristics

    SciTech Connect

    Seitzer, W.H.; Lovell, P.F.

    1982-05-01

    Shale oil, which forms a viscous, wax slurry below 25 C, was treated in several different ways to try to improve its flow characteristics as measured in a concentric cylinder viscometer. Removing the wax does not greatly improve the pumpability of the oil. Hydrotreatment of the whole oil to take out nitrogen, sulfur, and oxygen can lower the viscosity by a factor of five or more, even though the pour point is not greatly affected. Apparently hydrogenolysis of the nitrogen, sulfur, and oxygen lowers the molecular weight of the oil without much modification of the paraffinic wax. The pour point of the shale oil can be decreased with various commercial pour improvers. Sometimes an accompanying drop in viscosity is observed, but most of this decrease is not stable to shear in the viscometer.

  6. Cold adaptations.

    PubMed

    Launay, Jean-Claude; Savourey, Gustave

    2009-07-01

    Nowdays, occupational and recreational activities in cold environments are common. Exposure to cold induces thermoregulatory responses like changes of behaviour and physiological adjustments to maintain thermal balance either by increasing metabolic heat production by shivering and/or by decreasing heat losses consecutive to peripheral cutaneous vasoconstriction. Those physiological responses present a great variability among individuals and depend mainly on biometrical characteristics, age, and general cold adaptation. During severe cold exposure, medical disorders may occur such as accidental hypothermia and/or freezing or non-freezing cold injuries. General cold adaptations have been qualitatively classified by Hammel and quantitatively by Savourey. This last classification takes into account the quantitative changes of the main cold reactions: higher or lower metabolic heat production, higher or lesser heat losses and finally the level of the core temperature observed at the end of a standardized exposure to cold. General cold adaptations observed previously in natives could also be developed in laboratory conditions by continuous or intermittent cold exposures. Beside general cold adaptation, local cold adaptation exists and is characterized by a lesser decrease of skin temperature, a more pronounced cold induced vasodilation, less pain and a higher manual dexterity. Adaptations to cold may reduce the occurrence of accidents and improve human performance as surviving in the cold. The present review describes both general and local cold adaptations in humans and how they are of interest for cold workers.

  7. Linear Aerospike SR-71 Experiment (LASRE) during first in-flight cold flow test

    NASA Technical Reports Server (NTRS)

    1998-01-01

    This photograph shows the LASRE pod on the upper rear fuselage of an SR-71 aircraft during take-off of the first flight to experience an in-flight cold flow test. The flight occurred on 4 March 1998. The LASRE experiment was designed to provide in-flight data to help Lockheed Martin evaluate the aerodynamic characteristics and the handling of the SR-71 linear aerospike experiment configuration. The goal of the project was to provide in-flight data to help Lockheed Martin validate the computational predictive tools it was using to determine the aerodynamic performance of a future reusable launch vehicle. The joint NASA, Rocketdyne (now part of Boeing), and Lockheed Martin Linear Aerospike SR-71 Experiment (LASRE) completed seven initial research flights at Dryden Flight Research Center. Two initial flights were used to determine the aerodynamic characteristics of the LASRE apparatus (pod) on the back of the SR-71. Five later flights focused on the experiment itself. Two were used to cycle gaseous helium and liquid nitrogen through the experiment to check its plumbing system for leaks and to test engine operational characteristics. During the other three flights, liquid oxygen was cycled through the engine. Two engine hot-firings were also completed on the ground. A final hot-fire test flight was canceled because of liquid oxygen leaks in the test apparatus. The LASRE experiment itself was a 20-percent-scale, half-span model of a lifting body shape (X-33) without the fins. It was rotated 90 degrees and equipped with eight thrust cells of an aerospike engine and was mounted on a housing known as the 'canoe,' which contained the gaseous hydrogen, helium, and instrumentation gear. The model, engine, and canoe together were called a 'pod.' The experiment focused on determining how a reusable launch vehicle's engine flume would affect the aerodynamics of its lifting-body shape at specific altitudes and speeds. The interaction of the aerodynamic flow with the engine plume

  8. Partial oxidation for improved cold starts in alcohol-fueled engines: Phase 2 topical report

    SciTech Connect

    1998-04-01

    Alcohol fuels exhibit poor cold-start performance because of their low volatility. Neat alcohol engines become difficult, if not impossible, to start at temperatures close to or below freezing. Improvements in the cold-start performance (both time to start and emissions) are essential to capture the full benefits of alcohols as an alternative transportation fuel. The objective of this project was to develop a neat alcohol partial oxidation (POX) reforming technology to improve an alcohol engine`s ability to start at low temperatures (as low as {minus}30 C) and to reduce its cold-start emissions. The project emphasis was on fuel-grade ethanol (E95) but the technology can be easily extended to other alcohol fuels. Ultimately a compact, on-vehicle, ethanol POX reactor was developed as a fuel system component to produce a hydrogen-rich, fuel-gas mixture for cold starts. The POX reactor is an easily controllable combustion device that allows flexibility during engine startup even in the most extreme conditions. It is a small device that is mounted directly onto the engine intake manifold. The gaseous fuel products (or reformate) from the POX reactor exit the chamber and enter the intake manifold, either replacing or supplementing the standard ethanol fuel consumed during an engine start. The combustion of the reformate during startup can reduce engine start time and tail-pipe emissions.

  9. Horizon in Random Matrix Theory, the Hawking Radiation, and Flow of Cold Atoms

    SciTech Connect

    Franchini, Fabio; Kravtsov, Vladimir E.

    2009-10-16

    We propose a Gaussian scalar field theory in a curved 2D metric with an event horizon as the low-energy effective theory for a weakly confined, invariant random matrix ensemble (RME). The presence of an event horizon naturally generates a bath of Hawking radiation, which introduces a finite temperature in the model in a nontrivial way. A similar mapping with a gravitational analogue model has been constructed for a Bose-Einstein condensate (BEC) pushed to flow at a velocity higher than its speed of sound, with Hawking radiation as sound waves propagating over the cold atoms. Our work suggests a threefold connection between a moving BEC system, black-hole physics and unconventional RMEs with possible experimental applications.

  10. Horizon in random matrix theory, the Hawking radiation, and flow of cold atoms.

    PubMed

    Franchini, Fabio; Kravtsov, Vladimir E

    2009-10-16

    We propose a Gaussian scalar field theory in a curved 2D metric with an event horizon as the low-energy effective theory for a weakly confined, invariant random matrix ensemble (RME). The presence of an event horizon naturally generates a bath of Hawking radiation, which introduces a finite temperature in the model in a nontrivial way. A similar mapping with a gravitational analogue model has been constructed for a Bose-Einstein condensate (BEC) pushed to flow at a velocity higher than its speed of sound, with Hawking radiation as sound waves propagating over the cold atoms. Our work suggests a threefold connection between a moving BEC system, black-hole physics and unconventional RMEs with possible experimental applications.

  11. On the influence of cold-water coral mound size on flow hydrodynamics, and vice versa

    NASA Astrophysics Data System (ADS)

    Cyr, Frédéric; Haren, Hans; Mienis, Furu; Duineveld, Gerard; Bourgault, Daniel

    2016-01-01

    Using a combination of in situ observations and idealistic 2-D nonhydrostatic numerical simulations, the relation between cold-water coral (CWC) mound size and hydrodynamics is explored for the Rockall Bank area in the North Atlantic Ocean. It is shown that currents generated by topographically trapped tidal waves in this area cause large isopycnal depressions resulting from an internal hydraulic control above CWC mounds. The oxygen concentration distribution is used as a tracer to visualize the flow behavior and the turbulent mixing above the mounds. By comparing two CWC mounds of different sizes and located close to each other, it is shown that the resulting mixing is highly dependent on the size of the mound. The effects of the hydraulic control for mixing, nutrient availability, and ecosystem functioning are also discussed.

  12. An investigation of low Marangoni number fluid flow in a cold corner

    NASA Astrophysics Data System (ADS)

    Huber, Michael R.

    1993-06-01

    A large pool of liquid with a horizontal free surface is bounded on one side by a vertical solid wall. The wall is maintained at a cold temperature to a depth of unity, with a warmer temperature below that point. The fluid surface is assumed adiabatic, and average surface tension forces keep the surface flat. Surface tension is assumed to be a decreasing function of temperature, so that the surface thermal gradient associated with the temperature variations drives flow toward the comer. This problem is examined numerically for different Marangoni numbers ranging from 1 to 300 using a Green's function approximation method for viscous case (in the limit as the Reynolds number approaches zero).

  13. Postexercise cold-water immersion improves intermittent high-intensity exercise performance in normothermia.

    PubMed

    McCarthy, Avina; Mulligan, James; Egaña, Mikel

    2016-11-01

    A brief cold water immersion between 2 continuous high-intensity exercise bouts improves the performance of the latter compared with passive recovery in the heat. We investigated if this effect is apparent in normothermic conditions (∼19 °C), employing an intermittent high-intensity exercise designed to reflect the work performed at the high-intensity domain in team sports. Fifteen young active men completed 2 exhaustive cycling protocols (Ex1 and Ex2: 12 min at 85% ventilatory threshold (VT) and then an intermittent exercise alternating 30-s at 40% peak power (Ppeak) and 30 s at 90% Ppeak to exhaustion) separated by 15 min of (i) passive rest, (ii) 5-min cold-water immersion at 8 °C, and (iii) 10-min cold-water immersion at 8 °C. Core temperature, heart rate, rates of perceived exertion, and oxygen uptake kinetics were not different during Ex1 among conditions. Time to failure during the intermittent exercise was significantly (P < 0.05) longer during Ex2 following the 5- and 10-min cold-water immersions (7.2 ± 3.5 min and 7.3 ± 3.3 min, respectively) compared with passive rest (5.8 ± 3.1 min). Core temperature, heart rate, and rates of perceived exertion were significantly (P < 0.05) lower during most periods of Ex2 after both cold-water immersions compared with passive rest. The time constant of phase II oxygen uptake response during the 85% VT bout of Ex2 was not different among the 3 conditions. A postexercise, 5- to 10-min cold-water immersion increases subsequent intermittent high-intensity exercise compared with passive rest in normothermia due, at least in part, to reductions in core temperature, circulatory strain, and effort perception.

  14. Osmyb4 expression improves adaptive responses to drought and cold stress in transgenic apples.

    PubMed

    Pasquali, Gemma; Biricolti, Stefano; Locatelli, Franca; Baldoni, Elena; Mattana, Monica

    2008-10-01

    Constitutive expression of the rice cold-inducible Osmyb4 gene in transgenic Arabidopsis (Arabidopsis thaliana) plants improves adaptive responses to cold and drought stress, most likely due to the constitutive activation of several stress-inducible pathways and to the accumulation of several compatible solutes (e.g., glucose, fructose, sucrose, proline, glycine betaine and some aromatic compounds). Although the Osmyb4 gene seems able to activate stress responsive pathways in different species, we previously reported that its specific effect on stress tolerance depends on the transformed species. In the present work, we report the effects of the Osmyb4 expression for improving the stress response in apple (Malus pumila Mill.) plants. Namely, we found that the ectopic expression of the Myb4 transcription factor improved physiological and biochemical adaptation to cold and drought stress and modified metabolite accumulation. Based on these results it may be of interest to use Osmyb4 as a tool for improving the productivity of woody perennials under environmental stress conditions.

  15. Transplantation of Bone Marrow-Derived Mononuclear Cells Improves Mechanical Hyperalgesia, Cold Allodynia and Nerve Function in Diabetic Neuropathy

    PubMed Central

    Funakubo, Megumi; Hata, Masaki; Nakamura, Nobuhisa; Kobayashi, Yasuko; Kamiya, Hideki; Shibata, Taiga; Kondo, Masaki; Himeno, Tatsuhito; Matsubara, Tatsuaki; Oiso, Yutaka; Nakamura, Jiro

    2011-01-01

    Relief from painful diabetic neuropathy is an important clinical issue. We have previously shown that the transplantation of cultured endothelial progenitor cells or mesenchymal stem cells ameliorated diabetic neuropathy in rats. In this study, we investigated whether transplantation of freshly isolated bone marrow-derived mononuclear cells (BM-MNCs) alleviates neuropathic pain in the early stage of streptozotocin-induced diabetic rats. Two weeks after STZ injection, BM-MNCs or vehicle saline were injected into the unilateral hind limb muscles. Mechanical hyperalgesia and cold allodynia in SD rats were measured as the number of foot withdrawals to von Frey hair stimulation and acetone application, respectively. Two weeks after the BM-MNC transplantation, sciatic motor nerve conduction velocity (MNCV), sensory nerve conduction velocity (SNCV), sciatic nerve blood flow (SNBF), mRNA expressions and histology were assessed. The BM-MNC transplantation significantly ameliorated mechanical hyperalgesia and cold allodynia in the BM-MNC-injected side. Furthermore, the slowed MNCV/SNCV and decreased SNBF in diabetic rats were improved in the BM-MNC-injected side. BM-MNC transplantation improved the decreased mRNA expression of NT-3 and number of microvessels in the hind limb muscles. There was no distinct effect of BM-MNC transplantation on the intraepidermal nerve fiber density. These results suggest that autologous transplantation of BM-MNCs could be a novel strategy for the treatment of painful diabetic neuropathy. PMID:22125614

  16. Transplantation of bone marrow-derived mononuclear cells improves mechanical hyperalgesia, cold allodynia and nerve function in diabetic neuropathy.

    PubMed

    Naruse, Keiko; Sato, Jun; Funakubo, Megumi; Hata, Masaki; Nakamura, Nobuhisa; Kobayashi, Yasuko; Kamiya, Hideki; Shibata, Taiga; Kondo, Masaki; Himeno, Tatsuhito; Matsubara, Tatsuaki; Oiso, Yutaka; Nakamura, Jiro

    2011-01-01

    Relief from painful diabetic neuropathy is an important clinical issue. We have previously shown that the transplantation of cultured endothelial progenitor cells or mesenchymal stem cells ameliorated diabetic neuropathy in rats. In this study, we investigated whether transplantation of freshly isolated bone marrow-derived mononuclear cells (BM-MNCs) alleviates neuropathic pain in the early stage of streptozotocin-induced diabetic rats. Two weeks after STZ injection, BM-MNCs or vehicle saline were injected into the unilateral hind limb muscles. Mechanical hyperalgesia and cold allodynia in SD rats were measured as the number of foot withdrawals to von Frey hair stimulation and acetone application, respectively. Two weeks after the BM-MNC transplantation, sciatic motor nerve conduction velocity (MNCV), sensory nerve conduction velocity (SNCV), sciatic nerve blood flow (SNBF), mRNA expressions and histology were assessed. The BM-MNC transplantation significantly ameliorated mechanical hyperalgesia and cold allodynia in the BM-MNC-injected side. Furthermore, the slowed MNCV/SNCV and decreased SNBF in diabetic rats were improved in the BM-MNC-injected side. BM-MNC transplantation improved the decreased mRNA expression of NT-3 and number of microvessels in the hind limb muscles. There was no distinct effect of BM-MNC transplantation on the intraepidermal nerve fiber density. These results suggest that autologous transplantation of BM-MNCs could be a novel strategy for the treatment of painful diabetic neuropathy.

  17. Observations of capillary barriers and preferential flow in layered snow during cold laboratory experiments

    NASA Astrophysics Data System (ADS)

    Avanzi, Francesco; Hirashima, Hiroyuki; Yamaguchi, Satoru; Katsushima, Takafumi; De Michele, Carlo

    2016-09-01

    Data of liquid water flow around a capillary barrier in snow are still limited. To gain insight into this process, we carried out observations of dyed water infiltration in layered snow at 0 °C during cold laboratory experiments. We considered three different finer-over-coarser textures and three different water input rates. By means of visual inspection, horizontal sectioning, and measurements of liquid water content (LWC), capillary barriers and associated preferential flow were characterized. The flow dynamics of each sample were also simulated solving the Richards equation within the 1-D multi-layer physically based snow cover model SNOWPACK. Results revealed that capillary barriers and preferential flow are relevant processes ruling the speed of water infiltration in stratified snow. Both are marked by a high degree of spatial variability at centimeter scale and complex 3-D patterns. During unsteady percolation of water, observed peaks in bulk volumetric LWC at the interface reached ˜ 33-36 vol % when the upper layer was composed by fine snow (grain size smaller than 0.5 mm). However, LWC might locally be greater due to the observed heterogeneity in the process. Spatial variability in water transmission increases with grain size, whereas we did not observe a systematic dependency on water input rate for samples containing fine snow. The comparison between observed and simulated LWC profiles revealed that the implementation of the Richards equation reproduces the existence of a capillary barrier for all observed cases and yields a good agreement with observed peaks in LWC at the interface between layers.

  18. Interaction of field-aligned cold plasma flows with an equatorially-trapped hot plasma - Electrostatic shock formation

    NASA Technical Reports Server (NTRS)

    Singh, Nagendra

    1993-01-01

    Effects of equatorially trapped hot plasma on the highly supersonic cold-plasma flow occurring during early stage plasmaspheric refilling are studied by means of numerical simulations. It is shown that the equatorially trapped hot ions set up a potential barrier for the cold ion beams and facilitate formation of electrostatic shocks by reflecting them from the equatorial region. Simulations with and without the hot plasma show different flow properties; the formation of electrostatic shocks occur only in the former case. The simulation with the hot plasma also reveals that the magnetic trapping in conjunction with the evolution of the electrostatic potential barrier produces ion velocity distribution functions consisting of a cold core and a hot ring in the perpendicular velocity. Such a distribution function provides a source of free energy for equatorial waves. The corresponding electron population is warm and field-aligned.

  19. Interaction of field-aligned cold plasma flows with an equatorially-trapped hot plasma - Electrostatic shock formation

    NASA Technical Reports Server (NTRS)

    Singh, Nagendra

    1993-01-01

    Effects of equatorially trapped hot plasma on the highly supersonic cold-plasma flow occurring during early stage plasmaspheric refilling are studied by means of numerical simulations. It is shown that the equatorially trapped hot ions set up a potential barrier for the cold ion beams and facilitate formation of electrostatic shocks by reflecting them from the equatorial region. Simulations with and without the hot plasma show different flow properties; the formation of electrostatic shocks occur only in the former case. The simulation with the hot plasma also reveals that the magnetic trapping in conjunction with the evolution of the electrostatic potential barrier produces ion velocity distribution functions consisting of a cold core and a hot ring in the perpendicular velocity. Such a distribution function provides a source of free energy for equatorial waves. The corresponding electron population is warm and field-aligned.

  20. COLD-PCR: a new platform for highly improved mutation detection in cancer and genetic testing.

    PubMed

    Li, Jin; Makrigiorgos, G Mike

    2009-04-01

    PCR is widely employed as the initial DNA amplification step for genetic testing and cancer biomarker detection. However, a key limitation of PCR-based methods, including real-time PCR, is the inability to selectively amplify low levels of variant alleles in a wild-type allele background. As a result, downstream assays are limited in their ability to identify subtle genetic changes that can have a profound impact on clinical decision-making and outcome or that can serve as cancer biomarkers. We developed COLD-PCR (co-amplification at lower denaturation temperature-PCR) [Li, Wang, Mamon, Kulke, Berbeco and Makrigiorgos (2008) Nat. Med. 14, 579-584], a novel form of PCR that amplifies minority alleles selectively from mixtures of wild-type and mutation-containing sequences irrespective of the mutation type or position on the sequence. Consequently, COLD-PCR amplification from genomic DNA yields PCR products containing high-prevalence variant alleles that can be detected. Since PCR constitutes a ubiquitous initial step for almost all genetic analysis, COLD-PCR provides a general platform to improve the sensitivity of essentially all DNA-variation detection technologies including Sanger sequencing, pyrosequencing, single molecule sequencing, mutation scanning, mutation genotyping or methylation assays. COLD-PCR combined with real-time PCR provides a new approach to boost the capabilities of existing real-time mutation detection methods. We replaced regular PCR with COLD-PCR before sequencing or real-time mutation detection assays to improve mutation detection-sensitivity by up to 100-fold and identified novel p53/Kras/EGFR (epidermal growth factor receptor) mutations in heterogeneous cancer samples that were missed by all existing methods. For clinically relevant micro-deletions, COLD-PCR enabled exclusive amplification and isolation of the mutants. COLD-PCR is expected to have diverse applications in the fields of biomarker identification and tracing, genomic

  1. Effects of plasma aerodynamic actuation on oblique shock wave in a cold supersonic flow

    NASA Astrophysics Data System (ADS)

    Wang, Jian; Li, Yinghong; Cheng, Bangqin; Su, Changbing; Song, Huimin; Wu, Yun

    2009-08-01

    Wedge oblique shock wave control using an arc discharge plasma aerodynamic actuator was investigated both experimentally and theoretically. Schlieren photography measurements in a small-scale short-duration supersonic wind tunnel indicated that the shock wave angle decreased and its start point shifted upstream with the plasma aerodynamic actuation. Also the shock wave intensity weakened, as shown by the decrease in the gas static pressure ratio of flow downstream and upstream of the shock wave. Moreover, the shock wave control effect was intensified when a static magnetic field was applied. Under test conditions of Mach 2.2, magnetic control and input voltage 3 kV, the start point of the shock wave shifted 4 mm upstream, while its angle and intensity decreased 8.6% and 8.8%, respectively. A thermal choking model was proposed to deduce the change laws of oblique shock wave control by surface arc discharge. The theoretical result was consistent with the experimental result, which demonstrated that the thermal choking model can effectively forecast the effect of plasma actuation on an oblique shock wave in a cold supersonic flow.

  2. Expanding NevCAN capabilities: monitoring cold air drainage flow along a narrow wash within a Montane to PJ ecotone

    NASA Astrophysics Data System (ADS)

    Bird, B. M.; Devitt, D.

    2012-12-01

    Cold air drainage flows are a naturally occurring physical process of mountain systems. Plant communities that exist in cold air drainage basins respond to these localized cold air trends, and have been shown to be decoupled from larger global climate weather systems. The assumption that air temperature decreases with altitude is violated within these systems and climate model results based on this assumption would ultimately be inaccurate. In arid regions, high radiation loads lead to significant long wave radiation being emitted from the ground later in the day. As incoming radiation ceases, the surface very quickly loses energy through radiative processes, leading to surface inversions and enhanced cold air drainage opportunities. This study is being conducted in the Mojave desert on Sheep Mountain located between sites 3 and 4 of the NSF EPSCoR network. Monitoring of cold air drainage was initiated in September of 2011within a narrow ravine located between the 2164 and 2350 meter elevation. We have installed 25 towers (5 towers per location situated at the central low point in a ravine and at equal distances up the sides of the ravine on both the N and S facing slopes) to assess air temperatures from 0.1 meters to a height of 3 meters at 25m intervals. Our goal is to better understand the connection between cold air movement and plant physiological response. The species monitored in this study include: Pinus ponderosa (common name: Ponderosa Pine), Pinus pinyon (Pinyon Pine), Juniperus osteosperma (Utah juniper), Cercocarpus intricatus (Mountain Mahogany) and Symphoricarpos (snowberry). Hourly air temperature measurements within the wash are being captured from 100 ibuttons placed within PVC solar radiation shields. We are also developing a modeling approach to assess the three dimensional movement of cold air over time by incorporating wind vectors captured from 5 2D sonic anemometers. Wind velocities will be paired with air temperatures to better understand

  3. Restriction to large-scale gene flow vs. regional panmixia among cold seep Escarpia spp. (Polychaeta, Siboglinidae).

    PubMed

    Cowart, Dominique A; Huang, Chunya; Arnaud-Haond, Sophie; Carney, Susan L; Fisher, Charles R; Schaeffer, Stephen W

    2013-08-01

    The history of colonization and dispersal in fauna distributed among deep-sea chemosynthetic ecosystems remains enigmatic and poorly understood because of an inability to mark and track individuals. A combination of molecular, morphological and environmental data improves understanding of spatial and temporal scales at which panmixia, disruption of gene flow or even speciation may occur. Vestimentiferan tubeworms of the genus Escarpia are important components of deep -sea cold seep ecosystems, as they provide long-term habitat for many other taxa. Three species of Escarpia, Escarpia spicata [Gulf of California (GoC)], Escarpia laminata [Gulf of Mexico (GoM)] and Escarpia southwardae (West African Cold Seeps), have been described based on morphology, but are not discriminated through the use of mitochondrial markers (cytochrome oxidase subunit 1; large ribosomal subunit rDNA, 16S; cytochrome b). Here, we also sequenced the exon-primed intron-crossing Haemoglobin subunit B2 intron and genotyped 28 microsatellites to (i) determine the level of genetic differentiation, if any, among the three geographically separated entities and (ii) identify possible population structure at the regional scale within the GoM and West Africa. Results at the global scale support the occurrence of three genetically distinct groups. At the regional scale among eight sampling sites of E. laminata (n = 129) and among three sampling sites of E. southwardae (n = 80), no population structure was detected. These findings suggest that despite the patchiness and isolation of seep habitats, connectivity is high on regional scales.

  4. Influence of cold-water immersion on limb and cutaneous blood flow after exercise.

    PubMed

    Mawhinney, Chris; Jones, Helen; Joo, Chang Hwa; Low, David A; Green, Daniel J; Gregson, Warren

    2013-12-01

    This study aimed to determine the influence of cold (8°C) and cool (22°C) water immersion on femoral artery and cutaneous blood flow after exercise. Twelve men completed a continuous cycle exercise protocol at 70% peak oxygen uptake until a core temperature of 38°C was attained. Subjects were then immersed semireclined into 8°C or 22°C water to the iliac crest for 10 min or rested. Rectal and thigh skin temperature, deep and superficial muscle temperature, thigh and calf skin blood flow (laser Doppler flowmetry), and superficial femoral artery blood flow (duplex ultrasound) were measured before and up to 30 min after immersion. Indices of vascular conductance were calculated (flux and blood flow/mean arterial pressure). Reductions in rectal temperature were similar (0.6°C-0.7°C) in all three trials (P = 0.38). The mean ± SD thigh skin temperature during recovery was 25.4°C ± 3.8°C in the 8°C trial, which was lower than the 28.2°C ± 1.4°C and 33.78°C ± 1.0°C in the 22°C and control trials, respectively (P < 0.001). Recovery muscle temperature was also lowest in the 8°C trial (P < 0.01). Femoral artery conductance was similar after immersion in both cooling conditions and was lower (∼55%) compared with the control condition 30 min after immersion (P < 0.01). Similarly, there was greater thigh (P < 0.01) and calf (P < 0.05) cutaneous vasoconstriction during and after immersion in both cooling conditions relative to the control condition. Colder water temperatures may be more effective in the treatment of exercise-induced muscle damage and injury rehabilitation by virtue of greater reductions in muscle temperature and not muscle blood flow.

  5. Facility Activation and Characterization for IPD Oxidizer Turbopump Cold-Flow Testing at NASA Stennis Space Center

    NASA Technical Reports Server (NTRS)

    Sass, J. P.; Raines, N. G.; Farner, B. R.; Ryan, H. M.

    2004-01-01

    The Integrated Powerhead Demonstrator (IPD) is a 250K lbf (1.1 MN) thrust cryogenic hydrogen/oxygen engine technology demonstrator that utilizes a full flow staged combustion engine cycle. The Integrated Powerhead Demonstrator (IPD) is part of NASA's Next Generation Launch Technology (NGLT) program, which seeks to provide safe, dependable, cost-cutting technologies for future space launch systems. The project also is part of the Department of Defense's Integrated High Payoff Rocket Propulsion Technology (IHPRPT) program, which seeks to increase the performance and capability of today s state-of-the-art rocket propulsion systems while decreasing costs associated with military and commercial access to space. The primary industry participants include Boeing-Rocketdyne and GenCorp Aerojet. The intended full flow engine cycle is a key component in achieving all of the aforementioned goals. The IPD Program achieved a major milestone with the successful completion of the IPD Oxidizer Turbopump (OTP) cold-flow test project at the NASA John C. Stennis Space Center (SSC) E-1 test facility in November 2001. A total of 11 IPD OTP cold-flow tests were completed. Following an overview of the NASA SSC E-1 test facility, this paper addresses the facility aspects pertaining to the activation and the cold-flow testing of the IPD OTP. In addition, some of the facility challenges encountered during the test project are addressed.

  6. Flow boiling with enhancement devices for cold plate coolant channel design

    NASA Technical Reports Server (NTRS)

    Boyd, Ronald D.

    1991-01-01

    Future space exploration and commercialization will require more efficient heat rejection systems. For the required heat transfer rates, such systems must use advanced heat transfer techniques. Forced two phase flow boiling heat transfer with enhancements falls in this category. However, moderate to high quality two phase systems tend to require higher pressure losses. This report is divided into two major parts: (1) Multidimensional wall temperature measurement and heat transfer enhancement for top heated horizontal channels with flow boiling; and (2) Improved analytical heat transfer data reduction for a single side heated coolant channel. Part 1 summarizes over forty experiments which involve both single phase convection and flow boiling in a horizontal channel heated externally from the top side. Part 2 contains parametric dimensionless curves with parameters such as the coolant channel radius ratio, the Biot number, and the circumferential coordinate.

  7. Heating cold clumps by jet-inflated bubbles in cooling flow clusters

    NASA Astrophysics Data System (ADS)

    Hillel, Shlomi; Soker, Noam

    2014-12-01

    We simulate the evolution of dense-cool clumps embedded in the intracluster medium (ICM) of cooling flow clusters of galaxies in response to multiple jet-activity cycles, and find that the main heating process of the clumps is mixing with the hot shocked jets' gas, the bubbles, while shocks have a limited role. We use the PLUTO hydrodynamical code in two dimensions with imposed axisymmetry, to follow the thermal evolution of the clumps. We find that the inflation process of hot bubbles, which appear as X-ray deficient cavities in observations, is accompanied by complicated induced vortices inside and around the bubbles. The vorticity induces efficient mixing of the hot bubbles' gas with the ICM and cool clumps, resulting in a substantial increase of the temperature and entropy of the clumps. For the parameters used by us, heating by shocks barely competes with radiative cooling, even after 25 consecutive shocks excited during 0.5 Gyr of simulation. Some clumps are shaped to filamentary structure that can turn to observed optical filaments. We find that not all clumps are heated. Those that cool to very low temperatures will fall in and feed the central supermassive black hole, hence closing the feedback cycle in what is termed the cold feedback mechanism.

  8. Blood flow and muscle bio-energetics by 31P-nuclear magnetic resonance after local cold acclimation.

    PubMed

    Savourey, G; Clerc, L; Vallerand, A L; Leftheriotis, G; Mehier, H; Bittel, J H

    1992-01-01

    To clarify the origin of local cold adaptation and to define precisely its influence on muscle bio-energetics during local exercise, five subjects were subjected to repeated 5 degrees C cold water immersion of the right hand and forearm. The first aim of our investigation was therefore carried out by measuring local skin temperatures and peripheral blood flow during a cold hand test (5 degrees C, 5 min) followed by a 10-min recovery period. The 31P by nuclear magnetic resonance (31PNMR) muscle bio-energetic changes, indicating possible heat production changes, were measured during the recovery period. The second aim of our investigation was carried out by measuring 31PNMR muscle bioenergetics during handgrip exercise (10% of the maximal voluntary contraction for 5 min followed by a 10-min recovery period) performed both at a comfortable ambient temperature (22 degrees C; E) and after a cold hand test (EC), before and after local cold adaptation. Local cold adaptation, confirmed by warmer skin temperatures of the extremities (+30%, P less than 0.05), was related more to an increased peripheral blood flow, as shown by the smaller decrease in systolic peak [-245 (SEM 30) Hz vs -382 (SEM 95) Hz, P less than 0.05] than to a change in local heat production, because muscle bioenergetics did not vary. Acute local cold immersion decreased the inorganic phosphate:phosphocreatine (PC) ratio during EC compared to E [+0.006 (SEM 0.010) vs +0.078 (SEM 0.002) before acclimation and +0.029 (SEM 0.002) vs +0.090 (SEM 0.002) after acclimation respectively, P less than 0.05] without significant change in the PC:beta-adenosine triphosphate ratio and pH. Local adaptation did not modify these results statistically. The recovery of PC during E increased after acclimation [9.0 (SEM 0.2) min vs 3.0 (SEM 0.4) min, P less than 0.05]. These results suggested that local cold adaptation is related more to peripheral blood flow changes than to increased metabolic heat production in the muscle.

  9. One or 4 h of "in-house" reconditioning by machine perfusion after cold storage improve reperfusion parameters in porcine kidneys.

    PubMed

    Gallinat, Anja; Efferz, Patrik; Paul, Andreas; Minor, Thomas

    2014-11-01

    In-house machine perfusion after cold storage (hypothermic reconditioning) has been proposed as convenient tool to improve kidney graft function. This study investigated the role of machine perfusion duration for early reperfusion parameters in porcine kidneys. Kidney function after cold preservation (4 °C, 18 h) and subsequent reconditioning by one or 4 h of pulsatile, nonoxygenated hypothermic machine perfusion (HMP) was studied in an isolated kidney perfusion model in pigs (n = 6, respectively) and compared with simply cold-stored grafts (CS). Compared with CS alone, one or 4 h of subsequent HMP similarly and significantly improved renal flow and kidney function (clearance and sodium reabsorption) upon warm reperfusion, along with reduced perfusate concentrations of endothelin-1 and increased vascular release of nitric oxide. Molecular effects of HMP comprised a significant (vs CS) mRNA increase in the endothelial transcription factor KLF2 and lower expression of endothelin that were observed already at the end of one-hour HMP after CS. Reconditioning of cold-stored kidneys is possible, even if clinical logistics only permit one hour of therapy, while limited extension of the overall storage time by in-house machine perfusion might also allow for postponing of transplantation from night to early day work. © 2014 Steunstichting ESOT.

  10. Population genetic structure in Sabatieria (Nematoda) reveals intermediary gene flow and admixture between distant cold seeps from the Mediterranean Sea.

    PubMed

    De Groote, Annelies; Hauquier, Freija; Vanreusel, Ann; Derycke, Sofie

    2017-07-01

    There is a general lack of information on the dispersal and genetic structuring for populations of small-sized deep-water taxa, including free-living nematodes which inhabit and dominate the seafloor sediments. This is also true for unique and scattered deep-sea habitats such as cold seeps. Given the limited dispersal capacity of marine nematodes, genetic differentiation between such geographically isolated habitat patches is expected to be high. Against this background, we examined genetic variation in both mitochondrial (COI) and nuclear (18S and 28S ribosomal) DNA markers of 333 individuals of the genus Sabatieria, abundantly present in reduced cold-seep sediments. Samples originated from four Eastern Mediterranean cold seeps, separated by hundreds of kilometers, and one seep in the Southeast Atlantic. Individuals from the Mediterranean and Atlantic were divided into two separate but closely-related species clades. Within the Eastern Mediterranean, all specimens belonged to a single species, but with a strong population genetic structure (ΦST = 0.149). The haplotype network of COI contained 19 haplotypes with the most abundant haplotype (52% of the specimens) shared between all four seeps. The number of private haplotypes was high (15), but the number of mutations between haplotypes was low (1-8). These results indicate intermediary gene flow among the Mediterranean Sabatieria populations with no evidence of long-term barriers to gene flow. The presence of shared haplotypes and multiple admixture events indicate that Sabatieria populations from disjunct cold seeps are not completely isolated, with gene flow most likely facilitated through water current transportation of individuals and/or eggs. Genetic structure and molecular diversity indices are comparable to those of epiphytic shallow-water marine nematodes, while no evidence of sympatric cryptic species was found for the cold-seep Sabatieria.

  11. QTL pyramiding for improving of cold tolerance at fertilization stage in rice.

    PubMed

    Shinada, Hiroshi; Iwata, Natsuko; Sato, Takashi; Fujino, Kenji

    2014-03-01

    Vigorous cold tolerance at the fertilization stage (CTF) is a very important characteristic for stable rice production in cold temperature conditions. Because CTF is a quantitatively inherited trait, pyramiding quantitative trait loci (QTLs) using marker-assisted selection (MAS) is effective for improving CTF levels in rice breeding programs. We previously identified three QTLs controlling CTF, qCTF7, qCTF8 and qCTF12, using backcrossed inbred lines derived from a cross between rice cultivar Eikei88223 (vigorous CTF) and Suisei (very weak CTF). However, pyramiding of these QTLs for the application of MAS in practical rice breeding programs have not yet been elucidated. In this study, we examined the effect of pyramiding QTLs for improvement of CTF level using eight possible genotype classes from the 152 F3 population derived from a cross between Eikei88223 and Suisei. Increasing of CTF levels in combinations between qCTF7 and qCTF12 and between qCTF8 and qCTF12 were detected. Furthermore, we compared the haplotype pattern around the QTLs for CTF among the rice cultivars from Hokkaido. These results are useful for improvement of new cultivars with high CTF levels using MAS and identification of genetic resources with the novel QTL(s) for CTF.

  12. Full-scale cold-flow modelling of the SRC-I slurry fired heater at Creare, Inc. mixing and 1/sup 0/ downslope studies

    SciTech Connect

    Mehta, D.C.

    1984-05-01

    One of the major pieces of equipment in the SRC-I Demonstration Plant is the slurry fired heater. Because of the absence of any plant data at comparable combinations of operating severity, a cold-flow modelling experimental program was initiated at Creare, Inc. The first phase of the test program confirmed the fired heater design and established reliable boundaries of flow rates for proper operation of the fired heater. An experimental setup was designed and built at Creare to duplicate the piping arrangement and flow conditions of the fired heater. The pipe dimensions, flow rates, and fluid properties were selected to minimize areas of scale-up and extrapolation. This follow-up test program was developed to resolve concerns raised from the observations made in the first phase. Tests were conducted to establish the extent of mixing between the liquid carpet and the fast-moving liquid slugs above it. The other segment of the test program was designed to develop the flow regime and pressure drop data in the 1/sup 0/ downslope configuration. The results demonstrated a significant amount of mixing between the liquid carpet and the liquid slugs for water and the 400-cP fluid at the design flow conditions. The extent of mixing improved with increasing liquid and gas velocities and decreasing liquid viscosities. Adequate mixing was observed at liquid flow rates as low as 50% of the design flow conditions. Slug flow was observed at design conditions in the 1/sup 0/ downslope configuration. Although adequate mixing is expected in heater pipes, different techniques should be investigated to improve the extent of mixing, especially near the transition boundary. 4 references, 5 figures, 8 tables.

  13. Development of an advanced high efficiency coal combustor for boiler retrofit. Task 1, Cold flow burner development: Final report

    SciTech Connect

    LaFlesh, R.C.; Rini, M.J.; McGowan, J.G.

    1989-10-01

    The overall objective of this program is to develop a high efficiency advanced coal combustor (HEACC) for coal-based fuels capable of being retrofitted to industrial boilers originally designed for firing natural gas, distillate, and/or residual oil. The HEACC system is to be capable of firing microfine coal water fuel (MCWF), MCWF with alkali sorbent (for SO{sub 2} reduction), and dry microfine coal. Design priorities for the system are that it be simple to operate and will offer significant reductions in NO{sub x}, SO{sub x}, and particulate emissions as compared with current coal fired combustor technology. The specific objective of this report is to document the work carried out under Task 1.0 of this contract, ``Cold Flow Burner Development``. As are detailed in the report, key elements of this work included primary air swirler development, burner register geometry design, cold flow burner model testing, and development of burner scale up criteria.

  14. Fundamental Study of Direct Contact Cold Energy Release by Flowing Hot Air through Ice Particles Packed Layer

    NASA Astrophysics Data System (ADS)

    Aoyama, Sigeo; Inaba, Hideo

    This paper has dealt with the direct contact heat exchange characteristics between ice particles (average ice particle diameter : 3.10mm) packed in the rectangular cold energy storage vessel and flowing hot air as a heat transfer medium. The hot air bubbles ascended in the fluidized ice particles layer, and they were cooled down directly by melting ice particles. The temperature efficiency increased as Reynolds number Re increased because the hot air flowing in the layer became active. The dehumidity efficiency increased with an increase in modified Stefan number and Re, since the heat capacity of inlet air and heat transfer coefficient increased. Finally, some empirical correlations for temperature efficiency, dehumidity efficiency and the completion time of cold energy release were derived in terms of various nondimensional parameters.

  15. Improved visualization of flow field measurements

    NASA Technical Reports Server (NTRS)

    Miles, Jeffrey Hilton

    1991-01-01

    A capability was developed that makes it possible to apply to measured flow field data the visualization tools developed to display numerical solutions for computational fluid dynamic problems. The measurement monitor surface (MMS) procedure was applied to the analysis of flow field measurements within a low aspect ratio transonic axial flow fan rotor obtained with 2-D laser anemometry. The procedure generates input for the visualization tools developed to display numerical solutions for computational fluid dynamics problems. The relative Mach number contour plots obtained by this method resemble the conventional contour plots obtained by more traditional methods. The results show that the MMS procedure can be used to generate input for the multidimensional processing and analysis tools developed for data from numerical flow field simulations. They show that an experimenter can apply the MMS procedure to his data and then use an interactive graphics program to display scalar quantities like the Mach number by profiles, carpet plots, contour lines, and surfaces using various colors. Also, flow directionality can be shown by display of vector fields and particle traces.

  16. Flow boiling with enhancement devices for cold plate coolant channel design

    NASA Astrophysics Data System (ADS)

    Boyd, Ronald D., Sr.; Smith, Alvin

    1990-02-01

    The use of flow boiling for thermal energy transport is intended to provide an alternative for accommodating higher heat fluxes in commercial space systems. The objectives are to: (1) examine the variations in both the mean and local (axial and circumferential) heat transfer coefficients for a circular coolant channel with either smooth walls, spiral fins, or both spiral fins and a twisted tape; (2) examine the effects of channel diameter and subcooling; and (3) develop an improved reduction analysis and/or suggest possible heat transfer correlation of the present data. Freon-11 is the working fluid. Two-dimensional (circumferential and axial) wall temperature distributions were measured for coolant channels with the above noted internal geometries. The flow regimes which are being studied are: (1) single phase; (2) subcooled flow boiling; and (3) stratified flow boiling. The inside diameter of all test sections is near 1.0 cm. Cicumferentially averaged heat transfer coefficients at several axial locations were obtained for selected coolant channels for a mass velocity of 210 kg/sq m s, an exit pressure of 0.19 MPa (absolute), and an inlet subcooling of 20.8 C. Overall (averaged over the entire channel) heat transfer coefficients were compared for the above channel geometries. This comparison showed that the channel with large pitch spiral fins had higher heat transfer coefficients at all power levels.

  17. Flow boiling with enhancement devices for cold plate coolant channel design

    NASA Technical Reports Server (NTRS)

    Boyd, Ronald D., Sr.; Smith, Alvin

    1990-01-01

    The use of flow boiling for thermal energy transport is intended to provide an alternative for accommodating higher heat fluxes in commercial space systems. The objectives are to: (1) examine the variations in both the mean and local (axial and circumferential) heat transfer coefficients for a circular coolant channel with either smooth walls, spiral fins, or both spiral fins and a twisted tape; (2) examine the effects of channel diameter and subcooling; and (3) develop an improved reduction analysis and/or suggest possible heat transfer correlation of the present data. Freon-11 is the working fluid. Two-dimensional (circumferential and axial) wall temperature distributions were measured for coolant channels with the above noted internal geometries. The flow regimes which are being studied are: (1) single phase; (2) subcooled flow boiling; and (3) stratified flow boiling. The inside diameter of all test sections is near 1.0 cm. Cicumferentially averaged heat transfer coefficients at several axial locations were obtained for selected coolant channels for a mass velocity of 210 kg/sq m s, an exit pressure of 0.19 MPa (absolute), and an inlet subcooling of 20.8 C. Overall (averaged over the entire channel) heat transfer coefficients were compared for the above channel geometries. This comparison showed that the channel with large pitch spiral fins had higher heat transfer coefficients at all power levels.

  18. Improving simulations of precipitation phase and snowpack at a site subject to cold air intrusions: Snoqualmie Pass, WA

    NASA Astrophysics Data System (ADS)

    Wayand, Nicholas E.; Stimberis, John; Zagrodnik, Joseph P.; Mass, Clifford F.; Lundquist, Jessica D.

    2016-09-01

    Low-level cold air from eastern Washington often flows westward through mountain passes in the Washington Cascades, creating localized inversions and locally reducing climatological temperatures. The persistence of this inversion during a frontal passage can result in complex patterns of snow and rain that are difficult to predict. Yet these predictions are critical to support highway avalanche control, ski resort operations, and modeling of headwater snowpack storage. In this study we used observations of precipitation phase from a disdrometer and snow depth sensors across Snoqualmie Pass, WA, to evaluate surface-air-temperature-based and mesoscale-model-based predictions of precipitation phase during the anomalously warm 2014-2015 winter. Correlations of phase between surface-based methods and observations were greatly improved (r2 from 0.45 to 0.66) and frozen precipitation biases reduced (+36% to -6% of accumulated snow water equivalent) by using air temperature from a nearby higher-elevation station, which was less impacted by low-level inversions. Alternatively, we found a hybrid method that combines surface-based predictions with output from the Weather Research and Forecasting mesoscale model to have improved skill (r2 = 0.61) over both parent models (r2 = 0.42 and 0.55). These results suggest that prediction of precipitation phase in mountain passes can be improved by incorporating observations or models from above the surface layer.

  19. Improving the assessment of instream flow needs for fish populations

    SciTech Connect

    Sale, M.J. ); Otto, R.G. and Associates, Arlington, VA )

    1991-01-01

    Instream flow requirements are one of the most frequent and most costly environmental issues that must be addressed in developing hydroelectric projects. Existing assessment methods for determining instream flow requirements have been criticized for not including all the biological response mechanisms that regulate fishery resources. A new project has been initiated to study the biological responses of fish populations to altered stream flows and to develop improved ways of managing instream flows. 21 refs., 3 figs.

  20. Active shear flow control for improved combustion

    NASA Astrophysics Data System (ADS)

    Gutmark, E.; Parr, T. P.; Hanson-Parr, D. M.; Schadow, K. C.

    1990-01-01

    The acoustical and fluid dynamic facets of an excited premixed flame were studied experimentally to evaluate possibilities for development of a stabilizing closed-loop control system. The flame was analyzed as a nonlinear system which includes different subcomponents: acoustics, fluid dynamics, and chemical reaction. Identification of the acoustical and fluid dynamics subsystems is done by analyzing the transfer function, which was obtained by driving the system with both white-noise and a frequency-sweeping sine-wave. The features obtained by this analysis are compared to results of flow visualization and hot-wire flow-field and spectral measurements. The acoustical subsystem is determined by the resonant acoustic modes of the settling chamber. These modes are subsequently filtered and amplified by the flow shear layer, whose instability characteristics are dominated by the preferred mode frequency.

  1. Improving Snow Measurement Technology to Better Parameterise Cold Regions Hydrometeorology Models

    NASA Astrophysics Data System (ADS)

    Pomeroy, J.; Debeer, C.; Ellis, C.; Essery, R.; Helgason, W.; Kinar, N.; Link, T.; MacDonald, J.

    2008-12-01

    Marmot Creek Research Basin, in the Rocky Mountains of Alberta, Canada constitutes a long term cold regions hydrometeorological observatory with over 45 years of intensive observations in alpine and forested zones. Recently, novel combinations of measurement technology to snow have been deployed in Marmot Creek to advance the understanding of snow processes and to improve hydrometeorological models of streamflow and atmospheric variables. One advance has been the development and application of portable acoustic reflectometry to measure the density and structure of seasonal snowpacks using an audible sound wave. This has permitted the non-invasive measurement of snow water equivalent for both stationary and snow survey applications. Another advance has been the use of oblique time-lapse digital photography which is corrected for elevation and view angle from a LiDAR DEM to produce daily orthogonal snow covered area images of the alpine zone. These images are used to calculate snowcovered area and to develop and test improved snowcover melt and depletion algorithms. Deployment of 3-axis ultrasonic anemometers and fast hygrometers with collection of 10 Hz data and full correction for non-stationarity, axis rotation and other effects has shown that horizontal turbulence is often advected into mountain clearings and causes failure of traditional bulk transfer calculations of latent and sensible heat. For forest snow a hanging, weighed spruce tree and hanging, weighed sub-canopy troughs are used to capture intercepted snow load and unloaded snow fluxes respectively. These quantities provide the information needed to test detailed models of the snow interception and unloading processes. To quantify variations in sub-canopy energy for snowmelt, infrared imaging radiometers and narrow beam radiometers are used to measure thermal radiation exitance from needles, stems and trunks in forests of varying structure. These measurements are being used to develop improved models of

  2. Nature of convection-stabilized dc arcs in dual-flow nozzle geometry. I - The cold flow field and dc arc characteristics. II - Optical diagnostics and theory

    NASA Technical Reports Server (NTRS)

    Serbetci, Ilter; Nagamatsu, H. T.

    1990-01-01

    Steady-state low-current air arcs in a dual-flow nozzle system are studied experimentally. The cold flow field with no arc is investigated using a 12.7-mm diameter dual-flow nozzle in a steady-flow facility. Mach number and mass flux distributions are determined for various nozzle-pressure ratios and nozzle-gap spacing. It is found that the shock waves in the converging-diverging nozzles result in a decrease in overal resistance by about 15 percent. Also, Schlieren and differential interferometry techniques are used to visualize the density gradients within the arc plasma and thermal mantle. Both optical techniques reveal a laminar arc structure for a reservoir pressure of 1 atm at various current levels. Experimentally determined axial static pressure and cold-flow mass flux rate distributions and a channel-flow model with constant arc temperatre are used to solve the energy integral for the arc radius as a function of axial distance. The arc electric field strength, voltage, resistance, and power are determined with Ohm's law and the total heat transfer is related to arc power.

  3. QUANTITATIVE CHANGES IN REGIONAL CEREBRAL BLOOD FLOW INDUCED BY COLD, HEAT AND ISCHEMIC PAIN: A CONTINUOUS ARTERIAL SPIN LABELING STUDY

    PubMed Central

    Frölich, Michael A.; Deshpande, Hrishikesh; Ness, Timothy; Deutsch, Georg

    2012-01-01

    Background The development of arterial spin labeling methods, has allowed measuring regional cerebral blood flow (rCBF) quantitatively and to show the pattern of cerebral activity associated with any state such as a sustained pain state or changes due to a neurotropic drug. Methods We studied the differential effects of three pain conditions in ten healthy subjects on a 3T scanner during resting baseline, heat, cold and ischemic pain using continuous arterial spin labeling. Results Cold pain showed the greatest absolute rCBF increases in left anterior cingulate cortex, left amygdala, left angular gyrus, and Brodmann Area 6, and a significant rCBF decrease in the cerebellum. Changes in rCBF were characteristic of the type of pain condition: cold and heat pain showed increases, while the ischemic condition showed a reduction in mean absolute gray matter flow compared to rest. An association of subjects’ pain tolerance and cerebral blood flow was noted. Conclusions The observation that quantitative rCBF changes are characteristic of the pain task employed and that there is a consistent rCBF change in Brodman area 6, an area responsible for the integration of a motor response to pain, should provide extremely useful information in the quest to develop an imaging biomarker of pain. Conceivably, response in BA6 may serve as an objective measure of analgesic efficacy. PMID:22913924

  4. Relief, nocturnal cold-air flow and air quality in Kigali, Rwanda

    NASA Astrophysics Data System (ADS)

    Henninger, Sascha

    2013-04-01

    , this result is not reassuringly, because all measured residential districts in Kigali exceeded the recommendations of the WHO, too. This suggests that the inhabitants of Kigali are exposed to enormous levels of PM10 during most of their time outdoors. So PM10 levels are increasing in areas with high rates of traffic due to the exhaust of the vehicles and the stirring up of dust from the ground, but also in fact of burning wood for cooking etc. within the residential districts. Hazardous measuring trips could be detected for nighttime measurements. Because of high temperatures, high solar radiation and a non-typical missing cloud cover the urban surface could heat up extremely, which produced a cold-air flow from the ridges and the slopes down to the "Marais" at night. This cold-air flow takes away the suspended particulate matters, which tends to accumulate within the "Marais" on the bottom of the hills, the places where most residential neighborhoods could be found and agricultural fields were used. The distinctive relief caused an accumulation within small valleys. Unfortunately, these are the favourite places of living and agriculture and this tends to high indoor-air pollution.

  5. Single-site substitutions improve cold activity and increase thermostability of the dehairing alkaline protease (DHAP).

    PubMed

    Zhao, Hong-Yan; Wu, Li-Ying; Liu, Gang; Feng, Hong

    2016-12-01

    To engineer dehairing alkaline protease (DHAP) variants to improve cold activity and increase thermostability so these variants are suitable for the leather processing industry. Based on previous studies with bacterial alkaline proteases, double-site mutations (W106K/V149I and W106K/M124L) were introduced into the DHAP from Bacillus pumilus. Compared with the wild-type DHAP hydrolytic activity, the double-site variant W106K/V149I showed an increase in specific hydrolytic activity at 15 °C by 2.3-fold toward casein in terms of hydrolytic rate and 2.7-fold toward the synthetic peptide AAPF-pN by means of kcat/Km value. The thermostability of the variant (W106K/V149I) was improved with the half-life at 60 and 70 °C increased by 2.7- and 5.0-fold, respectively, when compared with the thermostability of the wild-type DHAP. Conclusively, an increase in the cold activity and thermostability of a bacterial alkaline protease was achieved by protein engineering.

  6. Cold adaptation improves the growth of seasonal influenza B vaccine viruses.

    PubMed

    Kim, Hyunsuh; Schoofs, Peter; Anderson, David A; Tannock, Gregory A; Rockman, Steven P

    2014-05-01

    Gene reassortment has proved useful in improving yields of influenza A antigens of egg-based inactivated vaccines, but similar approaches have been difficult with influenza B antigens. Current regulations for influenza vaccine seed viruses limit the number of egg passages and as a result resultant yields from influenza B vaccine seed viruses are frequently inconsistent. Therefore, reliable approaches to enhance yields of influenza B vaccine seed viruses are required for efficient vaccine manufacture. In the present study three stable cold-adapted (ca) mutants, caF, caM and caB derived from seasonal epidemic strains, B/Florida/4/2006, B/Malaysia/2506/2004 and B/Brisbane/60/2008 were prepared, which produced high hemagglutinin antigen yields and also increased viral yields of reassortants possessing the desired 6:2 gene constellation. The results demonstrate that consistent improvements in yields of influenza B viruses can be obtained by cold adaptation following extended passage. Taken together, the three ca viruses were shown to have potential as donor viruses for the preparation of high-yielding influenza B vaccine viruses by reassortment.

  7. Boundary layer flow dynamics at a cold-water coral reef

    NASA Astrophysics Data System (ADS)

    Guihen, Damien; White, Martin; Lundälv, Tomas

    2013-04-01

    The Tisler cold-water coral reef is a 2 km long reef in the north-eastern Skagerrak, Norway. The reef is comprised principally of Lophelia pertusa at depths between 70 and 160 m. Velocity shear and boundary layer shear stresses have been measured at Tisler Reef to quantify the effect of the reef structure on the benthic boundary layer (BBL) dynamics. Two different approaches to estimating the magnitude of the near seabed stress were employed: using a logarithmic (constant stress) boundary layer approach and direct Reynolds stress measurements. Resultant estimates of near seabed stresses using both methods were comparable. Using the logarithmic layer approach to estimate seabed stresses both inside and out of the reef structure demonstrated that, for any particular impinging flow strength, higher shear stresses were observed within the live coral region than in the dead coral rubble region with no live coral stands. Bottom shear stresses of up to 3.5 N m- 2 were measured within the reef complex and 1.2 N m- 2 in the rubble region outside the live reef. This difference is due to large roughness length scales inside the rough living coral area relative to the smaller scales in the coral rubble. Low frequency acoustic backscatter data, used as a proxy for relative suspended particulate matter concentrations, suggested that both local re-suspension and advection of suspended material most likely occur at, and through, the reef system. The high stresses measured inside the living reef may favour corals by increasing the degree of re-suspension for a given current speed and providing more particulates to the filter feeding polyps.

  8. Cold-flow performance of several variations of a ram-air-cooled plug nozzle for supersonic-cruise aircraft

    NASA Technical Reports Server (NTRS)

    Harrington, D. E.; Nosek, S. M.; Straight, D. M.

    1974-01-01

    Experimental data were obtained with a 21.59 cm (8.5 in.) diameter cold-flow model in a static altitude facility to determine the thrust and pumping characteristics of several variations of a ram-air-cooled plug nozzle. Tests were conducted over a range of nozzle pressure ratios simulating supersonic cruise and takeoff conditions. Primary throat area was also varied to simulate afterburner on and off. Effect of plug size, outer shroud length, primary nozzle geometry, and varying amounts of secondary flow were investigated. At a supersonic cruise pressure ratio of 27, nozzle efficiencies were 99.7 percent for the best configurations.

  9. Improved dual flow aluminum hydrogen peroxide battery

    SciTech Connect

    Marsh, C.; Licht, S.L.; Matthews, D.

    1993-11-30

    A novel dual flow battery configuration is provided comprising an aqueous hydrogen peroxide catholyte, an aqueous anolyte, a porous solid electrocatalyst capable of reducing said hydrogen peroxide and separating said anolyte, and an aluminum anode positioned within said anolyte. Separation of catholyte and anolyte chambers prevents hydrogen peroxide poisoning of the aluminum anode.

  10. Improved dual flow aluminum hydrogen peroxide battery

    NASA Astrophysics Data System (ADS)

    Marsh, Catherine; Licht, Stuart L.; Matthews, Donna

    1993-11-01

    A novel dual flow battery configuration is provided comprising an aqueous hydrogen peroxide catholyte, an aqueous anolyte, a porous solid electrocatalyst capable of reducing said hydrogen peroxide and separating said anolyte, and an aluminum anode positioned within said anolyte. Separation of catholyte and anolyte chambers prevents hydrogen peroxide poisoning of the aluminum anode.

  11. Flow boiling with enhancement devices for cold plate coolant channel design

    NASA Astrophysics Data System (ADS)

    Boyd, Ronald D., Sr.

    1989-02-01

    A research program to study the effect of enhancement devices on flow boiling heat transfer in coolant channels, which are heated either from the top side or uniformly, is discussed. Freon 11 is the working fluid involved. The specific objectives are: (1) examine the variations in both the mean and local (axial and circumferential) heat transfer coefficients for a circular coolant channel with either smooth walls or with both a twisted tape and spiral finned walls, (2) examine the effect channel diameter (and the length-to-diameter aspect ratio) variations for the smooth wall channel, and (3) develop an improved data reduction analysis.

  12. Flow boiling with enhancement devices for cold plate coolant channel design

    NASA Technical Reports Server (NTRS)

    Boyd, Ronald D., Sr.

    1989-01-01

    A research program to study the effect of enhancement devices on flow boiling heat transfer in coolant channels, which are heated either from the top side or uniformly, is discussed. Freon 11 is the working fluid involved. The specific objectives are: (1) examine the variations in both the mean and local (axial and circumferential) heat transfer coefficients for a circular coolant channel with either smooth walls or with both a twisted tape and spiral finned walls, (2) examine the effect channel diameter (and the length-to-diameter aspect ratio) variations for the smooth wall channel, and (3) develop an improved data reduction analysis.

  13. Improved Arterial Blood Oxygenation Following Intravenous Infusion of Cold Supersaturated Dissolved Oxygen Solution

    PubMed Central

    Grady, Daniel J; Gentile, Michael A; Riggs, John H; Cheifetz, Ira M

    2014-01-01

    BACKGROUND One of the primary goals of critical care medicine is to support adequate gas exchange without iatrogenic sequelae. An emerging method of delivering supplemental oxygen is intravenously rather than via the traditional inhalation route. The objective of this study was to evaluate the gas-exchange effects of infusing cold intravenous (IV) fluids containing very high partial pressures of dissolved oxygen (>760 mm Hg) in a porcine model. METHODS Juvenile swines were anesthetized and mechanically ventilated. Each animal received an infusion of cold (13 °C) Ringer’s lactate solution (30 mL/kg/hour), which had been supersaturated with dissolved oxygen gas (39.7 mg/L dissolved oxygen, 992 mm Hg, 30.5 mL/L). Arterial blood gases and physiologic measurements were repeated at 15-minute intervals during a 60-minute IV infusion of the supersaturated dissolved oxygen solution. Each animal served as its own control. RESULTS Five swines (12.9 ± 0.9 kg) were studied. Following the 60-minute infusion, there were significant increases in PaO2 and SaO2 (P < 0.05) and a significant decrease in PaCO2 (P < 0.05), with a corresponding normalization in arterial blood pH. Additionally, there was a significant decrease in core body temperature (P < 0.05) when compared to the baseline preinfusion state. CONCLUSIONS A cold, supersaturated dissolved oxygen solution may be intravenously administered to improve arterial blood oxygenation and ventilation parameters and induce a mild therapeutic hypothermia in a porcine model. PMID:25249764

  14. Improved arterial blood oxygenation following intravenous infusion of cold supersaturated dissolved oxygen solution.

    PubMed

    Grady, Daniel J; Gentile, Michael A; Riggs, John H; Cheifetz, Ira M

    2014-01-01

    One of the primary goals of critical care medicine is to support adequate gas exchange without iatrogenic sequelae. An emerging method of delivering supplemental oxygen is intravenously rather than via the traditional inhalation route. The objective of this study was to evaluate the gas-exchange effects of infusing cold intravenous (IV) fluids containing very high partial pressures of dissolved oxygen (>760 mm Hg) in a porcine model. Juvenile swines were anesthetized and mechanically ventilated. Each animal received an infusion of cold (13 °C) Ringer's lactate solution (30 mL/kg/hour), which had been supersaturated with dissolved oxygen gas (39.7 mg/L dissolved oxygen, 992 mm Hg, 30.5 mL/L). Arterial blood gases and physiologic measurements were repeated at 15-minute intervals during a 60-minute IV infusion of the supersaturated dissolved oxygen solution. Each animal served as its own control. Five swines (12.9 ± 0.9 kg) were studied. Following the 60-minute infusion, there were significant increases in PaO2 and SaO2 (P < 0.05) and a significant decrease in PaCO2 (P < 0.05), with a corresponding normalization in arterial blood pH. Additionally, there was a significant decrease in core body temperature (P < 0.05) when compared to the baseline preinfusion state. A cold, supersaturated dissolved oxygen solution may be intravenously administered to improve arterial blood oxygenation and ventilation parameters and induce a mild therapeutic hypothermia in a porcine model.

  15. Improving Patient Flow Utilizing a Collaborative Learning Model.

    PubMed

    Tibor, Laura C; Schultz, Stacy R; Cravath, Julie L; Rein, Russell R; Krecke, Karl N

    2016-01-01

    This initiative utilized a collaborative learning approach to increase knowledge and experience in process improvement and systems thinking while targeting improved patient flow in seven radiology modalities. Teams showed improvements in their project metrics and collectively streamlined the flow for 530 patients per day by improving patient lead time, wait time, and first case on-time start rates. In a post-project survey of 50 project team members, 82% stated they had more effective solutions as a result of the process improvement methodology, 84% stated they will be able to utilize the process improvement tools again in the future, and 98% would recommend participating in another project to a colleague.

  16. Wear Improvement of Tools in the Cold Forging Process for Long Hex Flange Nuts

    PubMed Central

    Hsia, Shao-Yi; Shih, Po-Yueh

    2015-01-01

    Cold forging has played a critical role in fasteners and has been widely used in automotive production, manufacturing, aviation and 3C (Computer, Communication, and Consumer electronics). Despite its extensive use in fastener forming and die design, operator experience and trial and error make it subjective and unreliable owing to the difficulty of controlling the development schedule. This study used finite element analysis to establish and simulate wear in automotive repair fastener manufacturing dies based on actual process conditions. The places on a die that wore most quickly were forecast, with the stress levels obtained being substituted into the Archard equation to calculate die wear. A 19.87% improvement in wear optimization occurred by applying the Taguchi quality method to the new design. Additionally, a comparison of actual manufacturing data to simulations revealed a nut forging size error within 2%, thereby demonstrating the accuracy of this theoretical analysis. Finally, SEM micrographs of the worn surfaces on the upper punch indicate that the primary wear mechanism on the cold forging die for long hex flange nuts was adhesive wear. The results can simplify the development schedule, reduce the number of trials and further enhance production quality and die life. PMID:28793589

  17. Improving cold storage and processing traits in potato through targeted gene knockout.

    PubMed

    Clasen, Benjamin M; Stoddard, Thomas J; Luo, Song; Demorest, Zachary L; Li, Jin; Cedrone, Frederic; Tibebu, Redeat; Davison, Shawn; Ray, Erin E; Daulhac, Aurelie; Coffman, Andrew; Yabandith, Ann; Retterath, Adam; Haun, William; Baltes, Nicholas J; Mathis, Luc; Voytas, Daniel F; Zhang, Feng

    2016-01-01

    Cold storage of potato tubers is commonly used to reduce sprouting and extend postharvest shelf life. However, cold temperature stimulates the accumulation of reducing sugars in potato tubers. Upon high-temperature processing, these reducing sugars react with free amino acids, resulting in brown, bitter-tasting products and elevated levels of acrylamide--a potential carcinogen. To minimize the accumulation of reducing sugars, RNA interference (RNAi) technology was used to silence the vacuolar invertase gene (VInv), which encodes a protein that breaks down sucrose to glucose and fructose. Because RNAi often results in incomplete gene silencing and requires the plant to be transgenic, here we used transcription activator-like effector nucleases (TALENs) to knockout VInv within the commercial potato variety, Ranger Russet. We isolated 18 plants containing mutations in at least one VInv allele, and five of these plants had mutations in all VInv alleles. Tubers from full VInv-knockout plants had undetectable levels of reducing sugars, and processed chips contained reduced levels of acrylamide and were lightly coloured. Furthermore, seven of the 18 modified plant lines appeared to contain no TALEN DNA insertions in the potato genome. These results provide a framework for using TALENs to quickly improve traits in commercially relevant autotetraploid potato lines.

  18. Wear Improvement of Tools in the Cold Forging Process for Long Hex Flange Nuts.

    PubMed

    Hsia, Shao-Yi; Shih, Po-Yueh

    2015-09-25

    Cold forging has played a critical role in fasteners and has been widely used in automotive production, manufacturing, aviation and 3C (Computer, Communication, and Consumer electronics). Despite its extensive use in fastener forming and die design, operator experience and trial and error make it subjective and unreliable owing to the difficulty of controlling the development schedule. This study used finite element analysis to establish and simulate wear in automotive repair fastener manufacturing dies based on actual process conditions. The places on a die that wore most quickly were forecast, with the stress levels obtained being substituted into the Archard equation to calculate die wear. A 19.87% improvement in wear optimization occurred by applying the Taguchi quality method to the new design. Additionally, a comparison of actual manufacturing data to simulations revealed a nut forging size error within 2%, thereby demonstrating the accuracy of this theoretical analysis. Finally, SEM micrographs of the worn surfaces on the upper punch indicate that the primary wear mechanism on the cold forging die for long hex flange nuts was adhesive wear. The results can simplify the development schedule, reduce the number of trials and further enhance production quality and die life.

  19. Unsaturated fatty acids from food and in the growth medium improve growth of Bacillus cereus under cold and anaerobic conditions.

    PubMed

    de Sarrau, Benoît; Clavel, Thierry; Zwickel, Nicolas; Despres, Jordane; Dupont, Sébastien; Beney, Laurent; Tourdot-Maréchal, Raphaëlle; Nguyen-The, Christophe

    2013-12-01

    In a chemically defined medium and in Luria broth, cold strongly reduced maximal population density of Bacillus cereus ATCC 14579 in anaerobiosis and caused formation of filaments. In cooked spinach, maximal population density of B. cereus in anaerobiosis was the same at cold and optimal temperatures, with normal cell divisions. The lipid containing fraction of spinach, but not the hydrophilic fraction, restored growth of B. cereus under cold and anaerobiosis when added to the chemically defined medium. This fraction was rich in unsaturated, low melting point fatty acids. Addition of phosphatidylcholine containing unsaturated, low melting point, fatty acids similarly improved B. cereus anaerobic growth at cold temperature. Addition of hydrogenated phosphatidylcholine containing saturated, high melting point, fatty acids did not modify growth. Fatty acids from phospholipids, from spinach and from hydrogenated phosphatidylcholine, although normally very rare in B. cereus, were inserted in the bacterium membrane. Addition of phospholipids rich in unsaturated fatty acids to cold and anaerobic cultures, increased fluidity of B. cereus membrane lipids, to the same level as those from B. cereus normally cold adapted, i.e. grown aerobically at 15 °C. B. cereus is therefore able to use external fatty acids from foods or from the growth medium to adapt its membrane to cold temperature under anaerobiosis, and to recover the maximal population density achieved at optimal temperature.

  20. Improved flow cytometer measurement of binding assays

    DOEpatents

    Saunders, G.C.

    1984-05-30

    The invention relates to a method of measuring binding assays carried out with different size particles wherein the binding assay sample is run through a flow cytometer without separating the sample from the marking agent. The amount of a binding reactant present in a sample is determined by providing particles with a coating of binder and also a known quantity of smaller particles with a coating of binder reactant. The binding reactant is the same as the binding reactant present in the sample. The smaller particles also contain a fluorescent chemical. The particles are combined with the sample and the binding reaction is allowed to occur for a set length of time followed by combining the smaller particles with the mixture of the particles and the sample produced and allowing the binding reactions to proceed to equilibrium. The fluorescence and light scatter of the combined mixture is then measured as the combined mixture passes through a flow cytometer equipped with a laser to bring about fluorescence, and the number and strength of fluorescent events are compared. A similar method is also provided for determining the amount of antigen present in the sample by providing spheres with an antibody coating and some smaller spheres with an antigen coating. (LEW)

  1. Cold preservation with hyperbranched polyglycerol-based solution improves kidney functional recovery with less injury at reperfusion in rats

    PubMed Central

    Li, Shadan; Liu, Bin; Guan, Qiunong; Chafeeva, Irina; Brooks, Donald E; Nguan, Christopher YC; Kizhakkedathu, Jayachandran N; Du, Caigan

    2017-01-01

    Minimizing donor organ injury during cold preservation (including cold perfusion and storage) is the first step to prevent transplant failure. We recently reported the advantages of hyperbranched polyglycerol (HPG) as a novel substitute for hydroxyethyl starch in UW solution for both cold heart preservation and cold kidney perfusion. This study evaluated the functional recovery of the kidney at reperfusion after cold preservation with HPG solution. The impact of HPG solution compared to conventional UW and HTK solutions on tissue weight and cell survival at 4°C was examined using rat kidney tissues and cultured human umbilical vein endothelial cells (HUVECs), respectively. The kidney protection by HPG solution was tested in a rat model of cold kidney ischemia-reperfusion injury, and was evaluated by histology and kidney function. Here, we showed that preservation with HPG solution prevented cell death in cultured HUVECs and edema formation in kidney tissues at 4°C similar to UW solution, whereas HTK solution was less effective. In rat model of cold ischemia-reperfusion injury, the kidneys perfused and subsequently stored 1-hour with cold HPG solution showed less leukocyte infiltration, less tubular damage and better kidney function (lower levels of serum creatinine and blood urea nitrogen) at 48 h of reperfusion than those treated with UW or HTK solution. In conclusion, our data show the superiority of HPG solution to UW or HTK solution in the cold perfusion and storage of rat kidneys, suggesting that the HPG solution may be a promising candidate for improved donor kidney preservation prior to transplantation. PMID:28337272

  2. DSC studies to evaluate the impact of bio-oil on cold flow properties and oxidation stability of bio-diesel.

    PubMed

    Garcia-Perez, Manuel; Adams, Thomas T; Goodrum, John W; Das, K C; Geller, Daniel P

    2010-08-01

    This paper describes the use of Differential Scanning Calorimetry (DSC) to evaluate the impact of varying mix ratios of bio-oil (pyrolysis oil) and bio-diesel on the oxidation stability and on some cold flow properties of resulting blends. The bio-oils employed were produced from the semi-continuous Auger pyrolysis of pine pellets and the batch pyrolysis of pine chips. The bio-diesel studied was obtained from poultry fat. The conditions used to prepare the bio-oil/bio-diesel blends as well as some of the fuel properties of these blends are reported. The experimental results suggest that the addition of bio-oil improves the oxidation stability of the resulting blends and modifies the crystallization behavior of unsaturated compounds. Upon the addition of bio-oil an increase in the oxidation onset temperature, as determined by DSC, was observed. The increase in bio-diesel oxidation stability is likely to be due to the presence of hindered phenols abundant in bio-oils. A relatively small reduction in DSC characteristic temperatures which are associated with cold flow properties was also observed but can likely be explained by a dilution effect.

  3. Mechanical pretreatment improving hemicelluloses removal from cellulosic fibers during cold caustic extraction.

    PubMed

    Li, Jianguo; Liu, Yishan; Duan, Chao; Zhang, Hongjie; Ni, Yonghao

    2015-09-01

    Hemicelluloses removal is a prerequisite for the production of high-quality cellulose (also known as dissolving pulp), and further recovery and utilization of hemicelluloses, which can be considered as a typical Integrated Forest Biorefinery concept. In this paper, a process of combined mechanical refining and cold caustic extraction (CCE), which was applied to a softwood sulfite sample, was investigated. The results showed that the hemicelluloses removal efficiency and selectivity were higher for the combined treatment than that for the CCE alone. The combined treatment can thus decrease the alkali concentration (from 8% to 4%) to achieve a similar hemicelluloses removal. The improved results were due to the fact that the mechanical refining resulted in increases in pore volume and diameter, water retention value (WRV) and specific surface area (SSA), all of which can make positive contributions to the hemicelluloses removal in the subsequent CCE process. Copyright © 2015 Elsevier Ltd. All rights reserved.

  4. Improvement in medium long-term frequency stability of the integrating sphere cold atom clock

    NASA Astrophysics Data System (ADS)

    Liu, Peng; Cheng, Huadong; Meng, Yanling; Wan, Jinyin; Xiao, Ling; Wang, Xiumei; Wang, Yaning; Liu, Liang

    2016-07-01

    The medium-long term frequency stability of the integrating sphere cold atom clock was improved.During the clock operation, Rb atoms were cooled and manipulated using cooling light diffusely reflected by the inner surface of a microwave cavity in the clock. This light heated the cavity and caused a frequency drift from the resonant frequency of the cavity. Power fluctuations of the cooling light led to atomic density variations in the cavity's central area, which increased the clock frequency instability through a cavity pulling effect. We overcame these limitations with appropriate solutions. A frequency stability of 3.5E-15 was achieved when the integrating time ? increased to 2E4 s.

  5. Radiant energy receiver having improved coolant flow control means

    DOEpatents

    Hinterberger, H.

    1980-10-29

    An improved coolant flow control for use in radiant energy receivers of the type having parallel flow paths is disclosed. A coolant performs as a temperature dependent valve means, increasing flow in the warmer flow paths of the receiver, and impeding flow in the cooler paths of the receiver. The coolant has a negative temperature coefficient of viscosity which is high enough such that only an insignificant flow through the receiver is experienced at the minimum operating temperature of the receiver, and such that a maximum flow is experienced at the maximum operating temperature of the receiver. The valving is accomplished by changes in viscosity of the coolant in response to the coolant being heated and cooled. No remotely operated valves, comparators or the like are needed.

  6. Improving flow distribution in influent channels using computational fluid dynamics.

    PubMed

    Park, No-Suk; Yoon, Sukmin; Jeong, Woochang; Lee, Seungjae

    2016-10-01

    Although the flow distribution in an influent channel where the inflow is split into each treatment process in a wastewater treatment plant greatly affects the efficiency of the process, and a weir is the typical structure for the flow distribution, to the authors' knowledge, there is a paucity of research on the flow distribution in an open channel with a weir. In this study, the influent channel of a real-scale wastewater treatment plant was used, installing a suppressed rectangular weir that has a horizontal crest to cross the full channel width. The flow distribution in the influent channel was analyzed using a validated computational fluid dynamics model to investigate (1) the comparison of single-phase and two-phase simulation, (2) the improved procedure of the prototype channel, and (3) the effect of the inflow rate on flow distribution. The results show that two-phase simulation is more reliable due to the description of the free-surface fluctuations. It should first be considered for improving flow distribution to prevent a short-circuit flow, and the difference in the kinetic energy with the inflow rate makes flow distribution trends different. The authors believe that this case study is helpful for improving flow distribution in an influent channel.

  7. Aging attenuates the coronary blood flow response to cold air breathing and isometric handgrip in healthy humans.

    PubMed

    Muller, Matthew D; Gao, Zhaohui; Mast, Jessica L; Blaha, Cheryl A; Drew, Rachel C; Leuenberger, Urs A; Sinoway, Lawrence I

    2012-04-15

    The purpose of this echocardiography study was to measure peak coronary blood flow velocity (CBV(peak)) and left ventricular function (via tissue Doppler imaging) during separate and combined bouts of cold air inhalation (-14 ± 3°C) and isometric handgrip (30% maximum voluntary contraction). Thirteen young adults and thirteen older adults volunteered to participate in this study and underwent echocardiographic examination in the left lateral position. Cold air inhalation was 5 min in duration, and isometric handgrip (grip protocol) was 2 min in duration; a combined stimulus (cold + grip protocol) and a cold pressor test (hand in 1°C water) were also performed. Heart rate, blood pressure, O(2) saturation, and inspired air temperature were monitored on a beat-by-beat basis. The rate-pressure product (RPP) was used as an index of myocardial O(2) demand, and CBV(peak) was used as an index of myocardial O(2) supply. The RPP response to the grip protocol was significantly blunted in older subjects (Δ1,964 ± 396 beats·min(-1)·mmHg) compared with young subjects (Δ3,898 ± 452 beats·min(-1)·mmHg), and the change in CBV(peak) was also blunted (Δ6.3 ± 1.2 vs. 11.2 ± 2.0 cm/s). Paired t-tests showed that older subjects had a greater change in the RPP during the cold + grip protocol [Δ2,697 ± 391 beats·min(-1)·mmHg compared with the grip protocol alone (Δ2,115 ± 375 beats·min(-1)·mmHg)]. An accentuated RPP response to the cold + grip protocol (compared with the grip protocol alone) without a concomitant increase in CBV(peak) may suggest a dissociation between the O(2) supply and demand in the coronary circulation. In conclusion, older adults have blunted coronary blood flow responses to isometric exercise.

  8. Improvement of Flow Quality in NAL Chofu Mach 10 Nozzle

    NASA Technical Reports Server (NTRS)

    Lacey, John; Inoue, Yasutoshi; Higashida, Akio; Inoue, Manabu; Ishizaka, Kouichi; Korte, John J.

    2002-01-01

    As a result of CFD analysis and remachining of the nozzle, the flow quality of the Mach 10 Hypersonic Wind Tunnel at NAL Chofu, Japan was improved. The subsequent test results validated the CFD analytical predictions by NASA and MHL.

  9. Investigation of CO2 capture using solid sorbents in a fluidized bed reactor: Cold flow hydrodynamics

    DOE PAGES

    Li, Tingwen; Dietiker, Jean -Francois; Rogers, William; ...

    2016-07-29

    Both experimental tests and numerical simulations were conducted to investigate the fluidization behavior of a solid CO2 sorbent with a mean diameter of 100 μm and density of about 480 kg/m, which belongs to Geldart's Group A powder. A carefully designed fluidized bed facility was used to perform a series of experimental tests to study the flow hydrodynamics. Numerical simulations using the two-fluid model indicated that the grid resolution has a significant impact on the bed expansion and bubbling flow behavior. Due to the limited computational resource, no good grid independent results were achieved using the standard models as farmore » as the bed expansion is concerned. In addition, all simulations tended to under-predict the bubble size substantially. Effects of various model settings including both numerical and physical parameters have been investigated with no significant improvement observed. The latest filtered sub-grid drag model was then tested in the numerical simulations. Compared to the standard drag model, the filtered drag model with two markers not only predicted reasonable bed expansion but also yielded realistic bubbling behavior. As a result, a grid sensitivity study was conducted for the filtered sub-grid model and its applicability and limitation were discussed.« less

  10. Flow boiling with enhancement devices for cold plate coolant channel design

    NASA Astrophysics Data System (ADS)

    Boyd, Ronald D.; Turknett, Jerry C.; Smith, Alvin

    1989-08-01

    The effects of enhancement devices on flow boiling heat transfer in circular coolant channels, which are heated over a fraction of their perimeters, are studied. The variations were examined in both the mean and local (axial, and circumferential) heat transfer coefficients for a circular coolant channel with either smooth walls or with both a twisted tape and spiral finned walls. Improvements were initiated in the present data reduction analysis. These efforts should lead to the development of heat transfer correlations which include effects of single side heat flux and enhancement device configuration. It is hoped that a stage will be set for the study of heat transfer and pressure drop in single sided heated systems under zero gravity conditions.

  11. Flow boiling with enhancement devices for cold plate coolant channel design

    NASA Technical Reports Server (NTRS)

    Boyd, Ronald D.; Turknett, Jerry C.; Smith, Alvin

    1989-01-01

    The effects of enhancement devices on flow boiling heat transfer in circular coolant channels, which are heated over a fraction of their perimeters, are studied. The variations were examined in both the mean and local (axial, and circumferential) heat transfer coefficients for a circular coolant channel with either smooth walls or with both a twisted tape and spiral finned walls. Improvements were initiated in the present data reduction analysis. These efforts should lead to the development of heat transfer correlations which include effects of single side heat flux and enhancement device configuration. It is hoped that a stage will be set for the study of heat transfer and pressure drop in single sided heated systems under zero gravity conditions.

  12. The role of cold and hot gas flows in feeding early-type galaxy formation

    NASA Astrophysics Data System (ADS)

    Johansson, Peter H.

    2016-10-01

    We study the evolution of the gaseous components in massive simulated galaxies and show that their early formation is fuelled by cold, low entropy gas streams. At lower redshifts of z <~ 3 the simulated galaxies are massive enough to support stable virial shocks resulting in a transition from cold to hot gas accretion. The gas accretion history of early-type galaxies is directly linked to the formation of their stellar component in the two phased formation scenario, in which the central parts of the galaxy assemble rapidly through in situ star formation and the later assembly is dominated primarily by minor stellar mergers.

  13. Development of a model and test equipment for cold flow tests at 500 atm of small nuclear light bulb configurations

    NASA Technical Reports Server (NTRS)

    Jaminet, J. F.

    1972-01-01

    A model and test equipment were developed and cold-flow-tested at greater than 500 atm in preparation for future high-pressure rf plasma experiments and in-reactor tests with small nuclear light bulb configurations. With minor exceptions, the model chamber is similar in design and dimensions to a proposed in-reactor geometry for tests with fissioning uranium plasmas in the nuclear furnace. The model and the equipment were designed for use with the UARL 1.2-MW rf induction heater in tests with rf plasmas at pressures up to 500 atm. A series of cold-flow tests of the model was then conducted at pressures up to about 510 atm. At 504 atm, the flow rates of argon and cooling water were 3.35 liter/sec (STP) and 26 gal/min, respectively. It was demonstrated that the model is capable of being operated for extended periods at the 500-atm pressure level and is, therefore, ready for use in initial high-pressure rf plasma experiments.

  14. Performance Improvements of the CYCOFOS Flow Model

    NASA Astrophysics Data System (ADS)

    Radhakrishnan, Hari; Moulitsas, Irene; Syrakos, Alexandros; Zodiatis, George; Nikolaides, Andreas; Hayes, Daniel; Georgiou, Georgios C.

    2013-04-01

    The CYCOFOS-Cyprus Coastal Ocean Forecasting and Observing System has been operational since early 2002, providing daily sea current, temperature, salinity and sea level forecasting data for the next 4 and 10 days to end-users in the Levantine Basin, necessary for operational application in marine safety, particularly concerning oil spills and floating objects predictions. CYCOFOS flow model, similar to most of the coastal and sub-regional operational hydrodynamic forecasting systems of the MONGOOS-Mediterranean Oceanographic Network for Global Ocean Observing System is based on the POM-Princeton Ocean Model. CYCOFOS is nested with the MyOcean Mediterranean regional forecasting data and with SKIRON and ECMWF for surface forcing. The increasing demand for higher and higher resolution data to meet coastal and offshore downstream applications motivated the parallelization of the CYCOFOS POM model. This development was carried out in the frame of the IPcycofos project, funded by the Cyprus Research Promotion Foundation. The parallel processing provides a viable solution to satisfy these demands without sacrificing accuracy or omitting any physical phenomena. Prior to IPcycofos project, there are been several attempts to parallelise the POM, as for example the MP-POM. The existing parallel code models rely on the use of specific outdated hardware architectures and associated software. The objective of the IPcycofos project is to produce an operational parallel version of the CYCOFOS POM code that can replicate the results of the serial version of the POM code used in CYCOFOS. The parallelization of the CYCOFOS POM model use Message Passing Interface-MPI, implemented on commodity computing clusters running open source software and not depending on any specialized vendor hardware. The parallel CYCOFOS POM code constructed in a modular fashion, allowing a fast re-locatable downscaled implementation. The MPI takes advantage of the Cartesian nature of the POM mesh, and use

  15. Trading water to improve environmental flow outcomes

    NASA Astrophysics Data System (ADS)

    Connor, Jeffery D.; Franklin, Brad; Loch, Adam; Kirby, Mac; Wheeler, Sarah Ann

    2013-07-01

    As consumptive extractions and water scarcity pressures brought about by climate change increase in many world river basins, so do the risks to water-dependent ecological assets. In response, public or not for profit environmental water holders (EWHs) have been established in many areas and bestowed with endowments of water and mandates to manage water for ecological outcomes. Water scarcity has also increasingly spawned water trade arrangements in many river basins, and in many instances, EWHs are now operating in water markets. A number of EWHs, especially in Australia, begin with an endowment of permanent water entitlements purchased from irrigators. Such water entitlements typically have relatively constant interannual supply profiles that often do not match ecological water demand involving flood pulses and periods of drying. This article develops a hydrologic-economic simulation model of the Murrumbidgee catchment within the Murray-Darling Basin to assess the scope of possibilities to improve environmental outcomes through EWH trading on an annual water lease market. We find that there are some modest opportunities for EWHs to improve environmental outcomes through water trade. The best opportunities occur in periods of drought and for ecological outcomes that benefit from moderately large floods. We also assess the extent to which EWH trading in annual water leases may create pecuniary externalities via bidding up or down the water lease prices faced by irrigators. Environmental water trading is found to have relatively small impacts on water market price outcomes. Overall our results suggest that the benefits of developing EWH trading may well justify the costs.

  16. The effects of minor constituents on biodiesel cold flow properties: Differential scanning calorimetry (DSC) analyses

    USDA-ARS?s Scientific Manuscript database

    Biodiesel is an alternative diesel fuel made from vegetable oils, animal fats and other lipid feedstocks. Fuel properties and performance of biodiesel during cold weather are influenced by factors related to lipid feedstock as well as small concentrations of monoacylglycerols and other minor constit...

  17. Improved cultivation and metagenomics as new tools for bioprospecting in cold environments.

    PubMed

    Vester, Jan Kjølhede; Glaring, Mikkel Andreas; Stougaard, Peter

    2015-01-01

    Only a small minority of microorganisms from an environmental sample can be cultured in the laboratory leaving the enormous bioprospecting potential of the uncultured diversity unexplored. This resource can be accessed by improved cultivation methods in which the natural environment is brought into the laboratory or through metagenomic approaches where culture-independent DNA sequence information can be combined with functional screening. The coupling of these two approaches circumvents the need for pure, cultured isolates and can be used to generate targeted information on communities enriched for specific activities or properties. Bioprospecting in extreme environments is often associated with additional challenges such as low biomass, slow cell growth, complex sample matrices, restricted access, and problematic in situ analyses. In addition, the choice of vector system and expression host may be limited as few hosts are available for expression of genes with extremophilic properties. This review summarizes the methods developed for improved cultivation as well as the metagenomic approaches for bioprospecting with focus on the challenges faced by bioprospecting in cold environments.

  18. Cold homes, fuel poverty and energy efficiency improvements: A longitudinal focus group approach.

    PubMed

    Grey, Charlotte N B; Schmieder-Gaite, Tina; Jiang, Shiyu; Nascimento, Christina; Poortinga, Wouter

    2017-08-01

    Cold homes and fuel poverty have been identified as factors in health and social inequalities that could be alleviated through energy efficiency interventions. Research on fuel poverty and the health impacts of affordable warmth initiatives have to date primarily been conducted using quantitative and statistical methods, limiting the way how fuel poverty is understood. This study took a longitudinal focus group approach that allowed exploration of lived experiences of fuel poverty before and after an energy efficiency intervention. Focus group discussions were held with residents from three low-income communities before (n = 28) and after (n = 22) they received energy efficiency measures funded through a government-led scheme. The results show that improving the energy efficiency of homes at risk of fuel poverty has a profound impact on wellbeing and quality of life, financial stress, thermal comfort, social interactions and indoor space use. However, the process of receiving the intervention was experienced by some as stressful. There is a need for better community engagement and communication to improve the benefits delivered by fuel poverty programmes, as well as further qualitative exploration to better understand the wider impacts of fuel poverty and policy-led intervention schemes.

  19. Improving the understanding and diagnosis of Earth system changes in cold regions

    NASA Astrophysics Data System (ADS)

    Lettenmaier, D. P.

    2015-12-01

    I review key hydrological state variables and fluxes relevant to cold regions, specifically snow, permafrost and seasonally frozen soils, lakes, and wetlands, and comment on the ability of current models to represent the associated processes, and the quality of the data sets upon which model development and diagnosis efforts rest. Although snow processes are relatively well represented in current generation land surface models, at least at large scales for deep mountain snowpacks, the representation of high latitude snow processes remain complicated by the role of snow redistribution, and of sublimation during the shoulder (especially spring) season. Most credible land surface models now include representations of permafrost, some of which perform well when forced with local climate data; however their performance over large areas is limited by spatial variability of key processes, including soil thermal characteristics. Likewise, many land surface models now represent the hydrology and energetics of lakes, which cover a substantial portion of the landscape in many high latitude environs. However, accurate representation of lakes requires knowledge of certain characteristics of their bathymetry and hydrological connectivity, information which is not always available. Likewise, the representation of wetlands in models, although improved in many cases, is limited by topography (and the role of microtopography, even at large scales). Nonetheless, increased attention to high latitude hydrological processes has demonstrably improved the fidelity of land surface representations over the last decade or so.

  20. Cold homes, fuel poverty and energy efficiency improvements: A longitudinal focus group approach

    PubMed Central

    Grey, Charlotte N. B.; Schmieder-Gaite, Tina; Jiang, Shiyu; Nascimento, Christina

    2017-01-01

    Cold homes and fuel poverty have been identified as factors in health and social inequalities that could be alleviated through energy efficiency interventions. Research on fuel poverty and the health impacts of affordable warmth initiatives have to date primarily been conducted using quantitative and statistical methods, limiting the way how fuel poverty is understood. This study took a longitudinal focus group approach that allowed exploration of lived experiences of fuel poverty before and after an energy efficiency intervention. Focus group discussions were held with residents from three low-income communities before (n = 28) and after (n = 22) they received energy efficiency measures funded through a government-led scheme. The results show that improving the energy efficiency of homes at risk of fuel poverty has a profound impact on wellbeing and quality of life, financial stress, thermal comfort, social interactions and indoor space use. However, the process of receiving the intervention was experienced by some as stressful. There is a need for better community engagement and communication to improve the benefits delivered by fuel poverty programmes, as well as further qualitative exploration to better understand the wider impacts of fuel poverty and policy-led intervention schemes. PMID:28890663

  1. Environmental Data Flow Six Sigma Process Improvement Savings Overview

    SciTech Connect

    Paige, Karen S

    2015-05-20

    An overview of the Environmental Data Flow Six Sigma improvement project covers LANL’s environmental data processing following receipt from the analytical laboratories. The Six Sigma project identified thirty-three process improvements, many of which focused on cutting costs or reducing the time it took to deliver data to clients.

  2. Estimation of water flow velocity in small plants using cold neutron imaging with D 2O tracer

    NASA Astrophysics Data System (ADS)

    Matsushima, U.; Herppich, W. B.; Kardjilov, N.; Graf, W.; Hilger, A.; Manke, I.

    2009-06-01

    Water flow imaging may help to better understand various problems related to water stress of plants. It may help to fully understand the water relations of plants. The objective of this research was to estimate the velocity of water flow in plant samples. Cut roses ( Rosa hybrida, var. 'Milva') were used as samples. Cold neutron radiography (CNR) was conducted at CONRAD, Helmholtz Center Berlin for Materials and Energy, Berlin, Germany. D 2O and H 2O were interchangeably injected into the water feeding system of the sample. After the uptake of D 2O, the neutron transmission increased due to the smaller attenuation coefficient of D 2O compared to H 2O. Replacement of D 2O in the rose peduncle was clearly observed. Three different optical flow algorithms, Block Matching, Horn-Schunck and Lucas-Kanade, were used to calculate the vector of D 2O tracer flow. The quality of sequential images providing sufficient spatial and temporal resolution allowed to estimate flow vector.

  3. Cool-season annual grasses interseeded into bermudagrass with improved cold-tolerance for grazing in the upper south

    USDA-ARS?s Scientific Manuscript database

    Bermudagrass [Cynodon dactylon (Pers.) L.] cultivars with improved cold tolerance can be utilized for grazing in the transition zone between the temperate northeast and subtropical southeast, but these bermudagrasses generally do not provide adequate growth for stocking until late May to early June....

  4. IMPROVED BIOMASS UTILIZATION THROUGH REMOTE FLOW SENSING

    SciTech Connect

    Washington University- St. Louis: Muthanna Al-Dahhan E-mail: muthanna@wustl.edu Rajneesh Varma Khursheed Karim Mehul Vesvikar Rebecca Hoffman Oak Ridge National Laboratory: David Depaoli, Email: depaolidw@ornl.gov Thomas Klasson Alan L. Wintenberg Charles W Alexander Lloyd Clonts Iowa Energy Center Norm Olson Email: nolson@energy.iastate.edu

    2007-03-26

    The growth of the livestock industry provides a valuable source of affordable, sustainable, and renewable bioenergy, while also requiring the safe disposal of the large quantities of animal wastes (manure) generated at dairy, swine, and poultry farms. If these biomass resources are mishandled and underutilized, major environmental problems will be created, such as surface and ground water contamination, odors, dust, ammonia leaching, and methane emission. Anaerobic digestion of animal wastes, in which microorganisms break down organic materials in the absence of oxygen, is one of the most promising waste treatment technologies. This process produces biogas typically containing {approx}65% methane and {approx}35% carbon dioxide. The production of biogas through anaerobic digestion from animal wastes, landfills, and municipal waste water treatment plants represents a large source of renewable and sustainable bio-fuel. Such bio-fuel can be combusted directly, used in internal combustion engines, converted into methanol, or partially oxidized to produce synthesis gas (a mixture of hydrogen and carbon monoxide) that can be converted to clean liquid fuels and chemicals via Fischer-Tropsch synthesis. Different design and mixing configurations of anaerobic digesters for treating cow manure have been utilized commercially and/or tested on a laboratory scale. These digesters include mechanically mixed, gas recirculation mixed, and slurry recirculation mixed designs, as well as covered lagoon digesters. Mixing is an important parameter for successful performance of anaerobic digesters. It enhances substrate contact with the microbial community; improves pH, temperature and substrate/microorganism uniformity; prevents stratification and scum accumulation; facilitates the removal of biogas from the digester; reduces or eliminates the formation of inactive zones (dead zones); prevents settling of biomass and inert solids; and aids in particle size reduction. Unfortunately

  5. An improved turbulence model for rotating shear flows*

    NASA Astrophysics Data System (ADS)

    Nagano, Yasutaka; Hattori, Hirofumi

    2002-01-01

    In the present study, we construct a turbulence model based on a low-Reynolds-number non-linear k e model for turbulent flows in a rotating channel. Two-equation models, in particular the non-linear k e model, are very effective for solving various flow problems encountered in technological applications. In channel flows with rotation, however, the explicit effects of rotation only appear in the Reynolds stress components. The exact equations for k and e do not have any explicit terms concerned with the rotation effects. Moreover, the Coriolis force vanishes in the momentum equation for a fully developed channel flow with spanwise rotation. Consequently, in order to predict rotating channel flows, after proper revision the Reynolds stress equation model or the non-linear eddy viscosity model should be used. In this study, we improve the non-linear k e model so as to predict rotating channel flows. In the modelling, the wall-limiting behaviour of turbulence is also considered. First, we evaluated the non-linear k e model using the direct numerical simulation (DNS) database for a fully developed rotating turbulent channel flow. Next, we assessed the non-linear k e model at various rotation numbers. Finally, on the basis of these assessments, we reconstruct the non-linear k e model to calculate rotating shear flows, and the proposed model is tested on various rotation number channel flows. The agreement with DNS and experiment data is quite satisfactory.

  6. Cold-Flow Study of Low Frequency Pressure Instability in Hybrid Rocket Motors

    NASA Technical Reports Server (NTRS)

    Jenkins, Rhonald M.

    1997-01-01

    Past experience with hybrid rockets has shown that certain motor operating conditions are conducive to the formation of low frequency pressure oscillations, or flow instabilities, within the motor. Both past and present work in the hybrid propulsion community acknowledges deficiencies in the understanding of such behavior, though it seems probable that the answer lies in an interaction between the flow dynamics and the combustion heat release. Knowledge of the fundamental flow dynamics is essential to the basic understanding of the overall stability problem. A first step in this direction was a study conducted at NASA Marshall Space Flight Center (MSFC), centered around a laboratory-scale two dimensional water flow model of a hybrid rocket motor. Principal objectives included: (1) visualization of flow and measurement of flow velocity distributions: (2) assessment of the importance of shear layer instabilities in driving motor pressure oscillations; (3) determination of the interactions between flow induced shear layers with the mainstream flow, the secondary (wall) throughflow, and solid boundaries; (4) investigation of the interactions between wall flow oscillations and the mainstream flow pressure distribution.

  7. Capture of instantaneous temperature in oscillating flows: use of constant-voltage anemometry to correct the thermal lag of cold wires operated by constant-current anemometry.

    PubMed

    Berson, Arganthaël; Poignand, Gaëlle; Blanc-Benon, Philippe; Comte-Bellot, Geneviève

    2010-01-01

    A new procedure for the instantaneous correction of the thermal inertia of cold wires operated by a constant-current anemometer is proposed for oscillating flows. The thermal inertia of cold wires depends both on the wire properties and on the instantaneous incident flow velocity. Its correction is challenging in oscillating flows because no relationship between flow velocity and heat transfer around the wire is available near flow reversal. The present correction procedure requires neither calibration data for velocity nor thermophysical or geometrical properties of the wires. The method relies on the splitting of the time lag of cold wires into two factors, which are obtained using a constant-voltage anemometer in the heated mode. The first factor, which is intrinsic to the wire, is deduced from time-constant measurements performed in a low-turbulence flow. The second factor, which depends on the instantaneous flow velocity, is acquired in situ. In oscillating flows, data acquisition can be synchronized with a reference signal so that the same wire is alternatively operated in the cold mode by a constant-current anemometer and in the heated mode by a constant-voltage anemometer. Validation experiments are conducted in an acoustic standing-wave resonator, for which the fluctuating temperature field along the resonator axis is known independently from acoustic pressure measurements, so that comparisons can be made with cold-wire measurements. It is shown that despite the fact that the wire experiences flow reversal, the new procedure recovers accurately the instantaneous temperature of the flow.

  8. Dry skin conditions are related to the recovery rate of skin temperature after cold stress rather than to blood flow.

    PubMed

    Yoshida-Amano, Yasuko; Nomura, Tomoko; Sugiyama, Yoshinori; Iwata, Kayoko; Higaki, Yuko; Tanahashi, Masanori

    2017-02-01

    Cutaneous blood flow plays an important role in the thermoregulation, oxygen supply, and nutritional support necessary to maintain the skin. However, there is little evidence for a link between blood flow and skin physiology. Therefore, we conducted surveys of healthy volunteers to determine the relationship(s) between dry skin properties and cutaneous vascular function. Water content of the stratum corneum, transepidermal water loss, and visual dryness score were investigated as dry skin parameters. Cutaneous blood flow in the resting state, the recovery rate (RR) of skin temperature on the hand after a cold-stress test, and the responsiveness of facial skin blood flow to local cooling were examined as indices of cutaneous vascular functions. The relationships between dry skin parameters and cutaneous vascular functions were assessed. The RR correlated negatively with the visual dryness score of skin on the leg but correlated positively with water content of the stratum corneum on the arm. No significant correlation between the resting state of blood flow and dry skin parameters was observed. In both the face and the body, deterioration in skin dryness from summer to winter was significant in subjects with low RR. The RR correlated well with the responsiveness of facial skin blood flow to local cooling, indicating that the RR affects systemic dry skin conditions. These results suggest that the RR but not blood flow at the resting state is associated with dry skin conditions and is involved in skin homeostasis during seasonal environmental changes. © 2016 The Authors. International Journal of Dermatology published by John Wiley & Sons Ltd on behalf of International Society of Dermatology.

  9. A novel approach to improve operation and performance in flow field-flow fractionation.

    PubMed

    Johann, Christoph; Elsenberg, Stephan; Roesch, Ulrich; Rambaldi, Diana C; Zattoni, Andrea; Reschiglian, Pierluigi

    2011-07-08

    A new system design and setup are proposed for the combined use of asymmetrical flow field-flow fractionation (AF4) and hollow-fiber flow field-flow fractionation (HF5) within the same instrumentation. To this purpose, three innovations are presented: (a) a new flow control scheme where focusing flow rates are measured in real time allowing to adjust the flow rate ratio as desired; (b) a new HF5 channel design consisting of two sets of ferrule, gasket and cap nut used to mount the fiber inside a tube. This design provides a mechanism for effective and straightforward sealing of the fiber; (c) a new AF4 channel design with only two fluid connections on the upper plate. Only one pump is needed to deliver the necessary flow rates. In the focusing/relaxation step the two parts of the focusing flow and a bypass flow flushing the detectors are created with two splits of the flow from the pump. In the elution mode the cross-flow is measured and controlled with a flow controller device. This leads to reduced pressure pulsations in the channel and improves signal to noise ratio in the detectors. Experimental results of the separation of bovine serum albumin (BSA) and of a mix of four proteins demonstrate a significant improvement in the HF5 separation performance, in terms of efficiency, resolution, and run-to-run reproducibility compared to what has been reported in the literature. Separation performance in HF5 mode is shown to be comparable to the performance in AF4 mode using a channel with two connections in the upper plate.

  10. Cold Atmospheric Plasma Modified Electrospun Scaffolds with Embedded Microspheres for Improved Cartilage Regeneration

    PubMed Central

    Zhu, Wei; Castro, Nathan J.; Cheng, Xiaoqian; Keidar, Michael; Zhang, Lijie Grace

    2015-01-01

    Articular cartilage is prone to degeneration and possesses extremely poor self-healing capacity due to inherent low cell density and the absence of a vasculature network. Tissue engineered cartilage scaffolds show promise for cartilage repair. However, there still remains a lack of ideal biomimetic tissue scaffolds which effectively stimulate cartilage regeneration with appropriate functional properties. Therefore, the objective of this study is to develop a novel biomimetic and bioactive electrospun cartilage substitute by integrating cold atmospheric plasma (CAP) treatment with sustained growth factor delivery microspheres. Specifically, CAP was applied to a poly(ε-caprolactone) electrospun scaffold with homogeneously distributed bioactive factors (transforming growth factor-β1 and bovine serum albumin) loaded poly(lactic-co-glycolic) acid microspheres. We have shown that CAP treatment renders electrospun scaffolds more hydrophilic thus facilitating vitronectin adsorption. More importantly, our results demonstrate, for the first time, CAP and microspheres can synergistically enhance stem cell growth as well as improve chondrogenic differentiation of human marrow-derived mesenchymal stem cells (such as increased glycosaminoglycan, type II collagen, and total collagen production). Furthermore, CAP can substantially enhance 3D cell infiltration (over two-fold increase in infiltration depth after 1 day of culture) in the scaffolds. By integrating CAP, sustained bioactive factor loaded microspheres, and electrospinning, we have fabricated a promising bioactive scaffold for cartilage regeneration. PMID:26222527

  11. A cold-induced phytosulfokine peptide is related to the improvement of loquat fruit chilling tolerance.

    PubMed

    Song, Huwei; Wang, Xinfeng; Hu, Weicheng; Yang, Xianghui; Diao, Enjie; Shen, Ting; Qiang, Qian

    2017-10-01

    A novel peptidomics approach was used to discover cold-induced peptides in loquat fruit. Twenty unique peptides derived from 18 proproteins were identified, and they were involved in sugar signalling, protein metabolism and stress response. The quantitative analysis revealed 7 peptides with more than 2-fold upregulation, especially a 4.96-fold increase detected in the phytosulfokine (PSK) peptide. To further evaluate effects of PSK1 on fruit chilling tolerance, weight loss, firmness and internal browning were investigated in PSK1-treated loquat fruit at 0°C. By contrast, these chilling injury symptoms were effectively reduced by PSK1. PSK1 markedly delayed decreases of ATP content and energy charge. The PSK1-treated fruit exhibited significantly lower activities of cell-wall degrading enzymes and transcripts of genes related to lignin synthesis. Our results demonstrated that PSK1 improves chilling tolerance of loquat fruit by maintaining high energy status and cell integrity. Peptidomics analysis provides a promising tool to discover some key peptides. Copyright © 2017 Elsevier Ltd. All rights reserved.

  12. Use of a static eliminator to improve powder flow.

    PubMed

    Pingali, Kalyana C; Hammond, Stephen V; Muzzio, Fernando J; Shinbrot, Troy

    2009-03-18

    Glidants and lubricants have long been used to improve the flow and processing of pharmaceutical and other powder blends. In this letter, we find that similar improvements can be attained, without additives, by using a simple static eliminator. These results indicate, first, that electrostatic effects on powder blends may be a significant cause of powder aggregation and flow instabilities, and second, that common additives such as magnesium stearate, colloidal silica, and talc may have as their chief effect the reduction of static. This suggests both that intelligent placement of static eliminators can eliminate the need for some of these additives and that judicious engineering of ionic and cationic additives may be effective in improving flow of "clingy" materials.

  13. Environmental cold exposure increases blood flow and affects pain sensitivity in the knee joints of CFA-induced arthritic mice in a TRPA1-dependent manner.

    PubMed

    Fernandes, Elizabeth S; Russell, Fiona A; Alawi, Khadija M; Sand, Claire; Liang, Lihuan; Salamon, Robin; Bodkin, Jennifer V; Aubdool, Aisah A; Arno, Matthew; Gentry, Clive; Smillie, Sarah-Jane; Bevan, Stuart; Keeble, Julie E; Malcangio, Marzia; Brain, Susan D

    2016-01-11

    The effect of cold temperature on arthritis symptoms is unclear. The aim of this study was to investigate how environmental cold affects pain and blood flow in mono-arthritic mice, and examine a role for transient receptor potential ankyrin 1 (TRPA1), a ligand-gated cation channel that can act as a cold sensor. Mono-arthritis was induced by unilateral intra-articular injection of complete Freund's adjuvant (CFA) in CD1 mice, and in mice either lacking TRPA1 (TRPA1 KO) or respective wildtypes (WT). Two weeks later, nociception and joint blood flow were measured following exposure to 10 °C (1 h) or room temperature (RT). Primary mechanical hyperalgesia in the knee was measured by pressure application apparatus; secondary mechanical hyperalgesia by automated von Frey system; thermal hyperalgesia by Hargreaves technique, and weight bearing by the incapacitance test. Joint blood flow was recorded by full-field laser perfusion imager (FLPI) and using clearance of (99m)Technetium. Blood flow was assessed after pretreatment with antagonists of either TRPA1 (HC-030031), substance P neurokinin 1 (NK1) receptors (SR140333) or calcitonin gene-related peptide (CGRP) (CGRP8-37). TRPA1, TAC-1 and CGRP mRNA levels were examined in dorsal root ganglia, synovial membrane and patellar cartilage samples. Cold exposure caused bilateral primary mechanical hyperalgesia 2 weeks after CFA injection, in a TRPA1-dependent manner. In animals maintained at RT, clearance techniques and FLPI showed that CFA-treated joints exhibited lower blood flow than saline-treated joints. In cold-exposed animals, this reduction in blood flow disappears, and increased blood flow in the CFA-treated joint is observed using FLPI. Cold-induced increased blood flow in CFA-treated joints was blocked by HC-030031 and not observed in TRPA1 KOs. Cold exposure increased TRPA1 mRNA levels in patellar cartilage, whilst reducing it in synovial membranes from CFA-treated joints. We provide evidence that environmental

  14. Cold habituation does not improve manual dexterity during rest and exercise in 5 °C

    NASA Astrophysics Data System (ADS)

    Muller, Matthew D.; Seo, Yongsuk; Kim, Chul-Ho; Ryan, Edward J.; Pollock, Brandon S.; Burns, Keith J.; Glickman, Ellen L.

    2014-04-01

    When exposed to a cold environment, a barehanded person experiences pain, cold sensation, and reduced manual dexterity. Both acute (e.g. exercise) and chronic (e.g. cold acclimatization or habituation) processes might lessen these negative effects. The purpose of this experiment was to determine the effect of cold habituation on physiology, perception, and manual dexterity during rest, exercise, and recovery in 5 °C. Six cold weather athletes (CWA) and eight non habituated men (NON) volunteered to participate in a repeated measures cross-over design. The protocol was conducted in 5 °C and was 90 min of resting cold exposure, 30 min of cycle ergometry exercise (50 % VO2 peak), and 60 min of seated recovery. Core and finger skin temperature, metabolic rate, Purdue Pegboard dexterity performance, hand pain, thermal sensation, and mood were quantified. Exercise-induced finger rewarming (EIFRW) was calculated for each hand. During 90 min of resting exposure to 5 °C, the CWA had a smaller reduction in finger temperature, a lower metabolic rate, less hand pain, and less negative mood. Despite this cold habituation, dexterity performance was not different between groups. In response to cycle ergometry, EIFRW was greater in CWA (~12 versus 7 °C) and occurred at lower core temperatures (37.02 versus 37.31 °C) relative to NON but dexterity was not greater during post-exercise recovery. The current data indicate that cold habituated men (i.e., CWA) do not perform better on the Purdue Pegboard during acute cold exposure. Furthermore, despite augmented EIFRW in CWA, dexterity during post-exercise recovery was similar between groups.

  15. Automatic flow-batch system for cold vapor atomic absorption spectroscopy determination of mercury in honey from Argentina using online sample treatment.

    PubMed

    Domínguez, Marina A; Grünhut, Marcos; Pistonesi, Marcelo F; Di Nezio, María S; Centurión, María E

    2012-05-16

    An automatic flow-batch system that includes two borosilicate glass chambers to perform sample digestion and cold vapor atomic absorption spectroscopy determination of mercury in honey samples was designed. The sample digestion was performed by using a low-cost halogen lamp to obtain the optimum temperature. Optimization of the digestion procedure was done using a Box-Behnken experimental design. A linear response was observed from 2.30 to 11.20 μg Hg L(-1). The relative standard deviation was 3.20% (n = 11, 6.81 μg Hg L(-1)), the sample throughput was 4 sample h(-1), and the detection limit was 0.68 μg Hg L(-1). The obtained results with the flow-batch method are in good agreement with those obtained with the reference method. The flow-batch system is simple, allows the use of both chambers simultaneously, is seen as a promising methodology for achieving green chemistry goals, and is a good proposal to improving the quality control of honey.

  16. Determination of mercury in agroindustrial samples by flow-injection cold vapor atomic absorption spectrometry using ion exchange and reductive elution.

    PubMed

    Gomes Neto, J A; Zara, L F; Rocha, J C; Santos, A; Dakuzaku, C S; Nóbrega, J A

    2000-03-06

    A flow-injection system with a Chelite-S(R) cationic resin packed minicolumn is proposed for the determination of trace levels of mercury in agroindustrial samples by cold vapor atomic absorption spectrometry. Improved sensitivity and selectivity are attained since mercuric ions are on-line concentrated whereas other potential interferents are discarded. With on-line reductive elution procedure, concentrated hydrochloric acid could be replaced by 10% w/v SnCl(2), in 6 M HCl as eluent. The reversed-intermittent stream either carries the atomic mercury to the flow cell in the forward direction or removes the residue from reactor/gas-liquid separator to a discarding flask in the opposite direction. Concentration and volume of reagent, acidity, flow rates, commutation times and potential interfering species were investigated. For 120 s preconcentration time, the proposed system handles about 25 samples h(-1) (50.0-500 ng l(-1)), consuming about 10 ml sample and 5 mg SnCl(2) per determination. The detection limit is 0.8 ng l(-1) and the relative standard deviation (RSD) (n=12) of a 76.7 ng l(-1) sample is about 5%. Results are in agreement with certified value of standard materials at 95% confidence level and good recoveries (97-128%) of spiked samples were found.

  17. A One-Dimensional Flow Model with Adiabatic Friction for Rapid Estimation of Cold Spray Flow Conditions

    NASA Astrophysics Data System (ADS)

    Ye, Hezhou; Yin, Yanhua; Wang, Jianfeng

    2015-08-01

    While commercially available computational fluid dynamic packages are employed nowadays to analyze the spraying behavior of the cold spray (CS) system and optimize the nozzle geometry design, using these packages is often prohibitive because of complex computational resource requirements and expensive copyright licenses. This paper proposes a quick and economical method for predicting the performance of the CS system, while asking for minimal computational resource. A one-dimensional adiabatic friction model with the consideration of friction was developed to calculate the critical pressure of nozzles under different expansion ratios and the gas/particle velocity at different spraying conditions. The accuracy of the critical pressure calculation was evidenced by polymeric nozzle destructive tests. The particle velocities achieved from the nozzles with different expansion ratios were measured and compared with the velocity values calculated by the model. The suggested adiabatic friction model is validated by the well-matched values between the calculated results and the experimental data.

  18. Building America Best Practices Series: Volume 3; Builders and Buyers Handbook for Improving New Home Efficiency, Comfort, and Durability in the Cold and Very Cold Climates

    SciTech Connect

    2005-08-01

    The guide book is a resource to help builders large and small build high-quality, energy-efficient homes that achieve 30% energy savings in space conditioning and water heating in the cold and very cold climates.

  19. Improved numerical methods for turbulent viscous recirculating flows

    NASA Technical Reports Server (NTRS)

    Turan, A.; Vandoormaal, J. P.

    1988-01-01

    The performance of discrete methods for the prediction of fluid flows can be enhanced by improving the convergence rate of solvers and by increasing the accuracy of the discrete representation of the equations of motion. This report evaluates the gains in solver performance that are available when various acceleration methods are applied. Various discretizations are also examined and two are recommended because of their accuracy and robustness. Insertion of the improved discretization and solver accelerator into a TEACH mode, that has been widely applied to combustor flows, illustrates the substantial gains to be achieved.

  20. Design and Cold-Flow Evaluation of a Miniature Mach 4 Ramjet

    DTIC Science & Technology

    2003-06-01

    19 4. GNUPLOT ...appropriate format using GRIDED for later use in the flow solution code OVERFLOW. After the solution was created, the residuals were plotted in GNUPLOT and...flow. 20 4. GNUPLOT This program is a UNIX-based plotting program that graphically displays data. It was used to display residual decay

  1. Numerical simulations of cold flow in a ramjet dump combustor with a choked exit nozzle

    NASA Astrophysics Data System (ADS)

    Menon, S.; Jou, W.-H.

    1986-10-01

    Simulations of the flow field were performed in a ramjet dump combustor equipped with an exit nozzle. The flow through the nozzle is choked numerically to simulate a realistic ramjet configuration. This also removes any ambiguities associated with the imposed outflow boundary conditions. The method of numerical choking is described. Large-scale motions similar to those in unchoked flow simulations are observed. The interaction between these large vortices and the choked throat is studied. Two simulations at Mach numbers 0.32 and 0.44 are discussed. Spectral analysis of the pressure and vorticity fluctuations in the combustor indicate a much richer spectral content when compared to unchoked flow results. Both convective-wave-dominated oscillations and acoustic oscillations appear to be present in the flow. Some preliminary results are presented.

  2. Improvement of a 2D numerical model of lava flows

    NASA Astrophysics Data System (ADS)

    Ishimine, Y.

    2013-12-01

    I propose an improved procedure that reduces an improper dependence of lava flow directions on the orientation of Digital Elevation Model (DEM) in two-dimensional simulations based on Ishihara et al. (in Lava Flows and Domes, Fink, JH eds., 1990). The numerical model for lava flow simulations proposed by Ishihara et al. (1990) is based on two-dimensional shallow water model combined with a constitutive equation for a Bingham fluid. It is simple but useful because it properly reproduces distributions of actual lava flows. Thus, it has been regarded as one of pioneer work of numerical simulations of lava flows and it is still now widely used in practical hazard prediction map for civil defense officials in Japan. However, the model include an improper dependence of lava flow directions on the orientation of DEM because the model separately assigns the condition for the lava flow to stop due to yield stress for each of two orthogonal axes of rectangular calculating grid based on DEM. This procedure brings a diamond-shaped distribution as shown in Fig. 1 when calculating a lava flow supplied from a point source on a virtual flat plane although the distribution should be circle-shaped. To improve the drawback, I proposed a modified procedure that uses the absolute value of yield stress derived from both components of two orthogonal directions of the slope steepness to assign the condition for lava flows to stop. This brings a better result as shown in Fig. 2. Fig. 1. (a) Contour plots calculated with the original model of Ishihara et al. (1990). (b) Contour plots calculated with a proposed model.

  3. Under EPA Settlement, Chicopee, Mass. Cold Storage Warehouse Company Improves Public Protections

    EPA Pesticide Factsheets

    A Chicopee, Mass., company that operates a cold storage warehouse is spending more than half a million dollars, primarily on public safety enhancements, to resolve claims it violated the federal Clean Air Act's chemical release prevention requirements...

  4. Cold Flow Plume Entrainment Test Final Report NTF Test Number 2456

    NASA Technical Reports Server (NTRS)

    Ruf, Joseph H.; McDaniels, David; Mishtawy, Jason; Ramachandran, Narayanan; Hammad, Khaled J.

    2005-01-01

    As part of the Space Shuttle Return to Flight (RTF) program, Marshall Space Flight Center (MSFC) performed computational fluid dynamics (CFD) analysis to define the velocity flowfields around the Shuttle stack at liftoff. These CFD predicted velocity flowfields were used in debris transport analysis (DTA). High speed flows such as plumes induce or 'entrain' mass from the surrounding environment. Previous work had shown that CFD analysis over-predicts plume induced flows. Therefore, the DTA would tend to 1) predict more debris impacts, and 2) the debris velocity (and kinetic energy) of those impacts would be too high. At a November, 2004 peer-review it was recommended that the Liftoff DTA team quantify the uncertainty in the DTA caused by the CFD's over prediction of plume induced flow. To do so, the Liftoff DTA team needed benchmark quality data for plume induced flow to quantify the CFD accuracy and its effect on the DTA. MSFC's Nozzle Test Facility (NTF) conducted the "Nozzle Induced Flows test, P#2456" to obtain experimental data for plume induced flows for nozzle flow exhausting into q quiescent freestream. Planning for the test began in December, 2004 and the experimental data was obtained in February and March of 2005. The funding for this test was provided by MSFC's Space Shuttle Propulsion Systems Integration and Engineering office.

  5. Flow pattern changes improve roller cone bit performance

    SciTech Connect

    Huffstutler, A.D.

    1996-05-06

    Improving the flow pattern through and around roller cone bits has increased penetration rate and footage while dropping the cost per foot drilled. These changes to the flow area around the bit help clean the bit and borehole more efficiently. By eliminating the protruding nozzle bosses, increasing nozzle bore size, narrowing the width of the bit arm segments, and providing a convex spherical dome, flow trajectories have been improved. These altered flow trajectories have eliminated hydraulic dead spots commonly found around current roller cone rock bit configurations. Nozzles are directed significantly more inward, toward the well bore bottom and away from the edge of the borehole. The flow impacts the bottom of the hole where it is needed most. Further performance enhancement features include an angled ramp on the shirt-tail portion of the arm to aid in lifting the cuttings upward, away from the cones and the bearing seals. Changing contours of the bit arms in the nozzle and bearing areas also improves cleaning and prevents cuttings from packing off in the bearing seal area.

  6. An improved near-wall treatment for turbulent channel flows

    NASA Astrophysics Data System (ADS)

    El Gharbi, Najla; Absi, Rafik; Benzaoui, Ahmed; Bennacer, Rachid

    2011-01-01

    The success of predictions of wall-bounded turbulent flows requires an accurate description of the flow in the near-wall region. This article presents a comparative study between different near-wall treatments and presents an improved method. The study is applied to fully developed plane channel flow (i.e. the flow between two infinitely large plates). Simulations were performed using Fluent. Near-wall treatments available in Fluent were tested: standard wall functions, non-equilibrium wall function and enhanced wall treatment. A user defined function (UDF), based on an analytical profile for the turbulent kinetic energy (Absi, R., 2008. Analytical solutions for the modeled k-equation. ASME Journal of Applied Mechanics, 75 (4), 044501), is developed and implemented. Predicted turbulent kinetic energy profiles are presented and validated by DNS data.

  7. Improved numerical methods for turbulent viscous recirculating flows

    NASA Technical Reports Server (NTRS)

    Vandoormaal, J. P.; Turan, A.; Raithby, G. D.

    1986-01-01

    The objective of the present study is to improve both the accuracy and computational efficiency of existing numerical techniques used to predict viscous recirculating flows in combustors. A review of the status of the study is presented along with some illustrative results. The effort to improve the numerical techniques consists of the following technical tasks: (1) selection of numerical techniques to be evaluated; (2) two dimensional evaluation of selected techniques; and (3) three dimensional evaluation of technique(s) recommended in Task 2.

  8. Cold Flow Diluent Mixing Study Using Radial High Density Ratio Jets into a Circular Freestream

    DTIC Science & Technology

    2010-07-01

    CAD) solid models. From the CAD model, computational grids are generated for the CFD simulations using Gridgen v.15. Appropriate flow modeling...release, Distribution is unlimited 4 Figure 2: Geometry and Mesh Boundaries in Water Jet Simulations Grid Generation and Flow Model GRIDGEN v.15...generated using GRIDGEN v.15. Figure 4 shows the computational domain for the dual-jet configuration. The modeled domain contains 1.3 to 1.8

  9. Packet Scheduling Mechanism to Improve Quality of Short Flows and Low-Rate Flows

    NASA Astrophysics Data System (ADS)

    Yokota, Kenji; Asaka, Takuya; Takahashi, Tatsuro

    In recent years elephant flows are increasing by expansion of peer-to-peer (P2P) applications on the Internet. As a result, bandwidth is occupied by specific users triggering unfair resource allocation. The main packet-scheduling mechanism currently employed is first-in first-out (FIFO) where the available bandwidth of short flows is limited by elephant flows. Least attained service (LAS), which decides transfer priority of packets by the total amount of transferred data in all flows, was proposed to solve this problem. However, routers with LAS limit flows with large amount of transferred data even if they are low-rate. Therefore, it is necessary to improve the quality of low-rate flows with long holding times such as voice over Internet protocol (VoIP) applications. This paper proposes rate-based priority control (RBPC), which calculates the flow rate and control the priority by using it. Our proposed method can transfer short flows and low-rate flows in advance. Moreover, its fair performance is shown through simulations.

  10. Augmenting transport versus increasing cold storage to improve vaccine supply chains.

    PubMed

    Haidari, Leila A; Connor, Diana L; Wateska, Angela R; Brown, Shawn T; Mueller, Leslie E; Norman, Bryan A; Schmitz, Michelle M; Paul, Proma; Rajgopal, Jayant; Welling, Joel S; Leonard, Jim; Chen, Sheng-I; Lee, Bruce Y

    2013-01-01

    When addressing the urgent task of improving vaccine supply chains, especially to accommodate the introduction of new vaccines, there is often a heavy emphasis on stationary storage. Currently, donations to vaccine supply chains occur largely in the form of storage equipment. This study utilized a HERMES-generated detailed, dynamic, discrete event simulation model of the Niger vaccine supply chain to compare the impacts on vaccine availability of adding stationary cold storage versus transport capacity at different levels and to determine whether adding stationary storage capacity alone would be enough to relieve potential bottlenecks when pneumococcal and rotavirus vaccines are introduced by 2015. Relieving regional level storage bottlenecks increased vaccine availability (by 4%) more than relieving storage bottlenecks at the district (1% increase), central (no change), and clinic (no change) levels alone. Increasing transport frequency (or capacity) yielded far greater gains (e.g., 15% increase in vaccine availability when doubling transport frequency to the district level and 18% when tripling). In fact, relieving all stationary storage constraints could only increase vaccine availability by 11%, whereas doubling the transport frequency throughout the system led to a 26% increase and tripling the frequency led to a 30% increase. Increasing transport frequency also reduced the amount of stationary storage space needed in the supply chain. The supply chain required an additional 61,269L of storage to relieve constraints with the current transport frequency, 55,255L with transport frequency doubled, and 51,791L with transport frequency tripled. When evaluating vaccine supply chains, it is important to understand the interplay between stationary storage and transport. The HERMES-generated dynamic simulation model showed how augmenting transport can result in greater gains than only augmenting stationary storage and can reduce stationary storage needs.

  11. Augmenting Transport versus Increasing Cold Storage to Improve Vaccine Supply Chains

    PubMed Central

    Haidari, Leila A.; Connor, Diana L.; Wateska, Angela R.; Brown, Shawn T.; Mueller, Leslie E.; Norman, Bryan A.; Schmitz, Michelle M.; Paul, Proma; Rajgopal, Jayant; Welling, Joel S.; Leonard, Jim; Chen, Sheng-I; Lee, Bruce Y.

    2013-01-01

    Background When addressing the urgent task of improving vaccine supply chains, especially to accommodate the introduction of new vaccines, there is often a heavy emphasis on stationary storage. Currently, donations to vaccine supply chains occur largely in the form of storage equipment. Methods This study utilized a HERMES-generated detailed, dynamic, discrete event simulation model of the Niger vaccine supply chain to compare the impacts on vaccine availability of adding stationary cold storage versus transport capacity at different levels and to determine whether adding stationary storage capacity alone would be enough to relieve potential bottlenecks when pneumococcal and rotavirus vaccines are introduced by 2015. Results Relieving regional level storage bottlenecks increased vaccine availability (by 4%) more than relieving storage bottlenecks at the district (1% increase), central (no change), and clinic (no change) levels alone. Increasing transport frequency (or capacity) yielded far greater gains (e.g., 15% increase in vaccine availability when doubling transport frequency to the district level and 18% when tripling). In fact, relieving all stationary storage constraints could only increase vaccine availability by 11%, whereas doubling the transport frequency throughout the system led to a 26% increase and tripling the frequency led to a 30% increase. Increasing transport frequency also reduced the amount of stationary storage space needed in the supply chain. The supply chain required an additional 61,269L of storage to relieve constraints with the current transport frequency, 55,255L with transport frequency doubled, and 51,791L with transport frequency tripled. Conclusions When evaluating vaccine supply chains, it is important to understand the interplay between stationary storage and transport. The HERMES-generated dynamic simulation model showed how augmenting transport can result in greater gains than only augmenting stationary storage and can reduce

  12. Temperature-stable lithium niobate electro-optic Q-switch for improved cold performance

    NASA Astrophysics Data System (ADS)

    Jundt, Dieter H.

    2014-10-01

    Lithium niobate (LN) is commonly used as an electro optic (EO) Q-switch material in infrared targeting lasers because of its relatively low voltage requirements and low cost compared to other crystals. A common challenge is maintaining good performance at the sub-freezing temperatures often experienced during flight. Dropping to low temperature causes a pyro-electric charge buildup on the optical faces that leads to birefringence non-uniformity and depolarization resulting in poor hold-off and premature lasing. The most common solution has been to use radioactive americium to ionize the air around the crystal and bleed off the charge, but the radioactive material requires handling and disposal procedures that can be problematic. We have developed a superior solution that is now being implemented by multiple defense system suppliers. By applying a low level thermo-chemical reduction to the LN crystal optical faces we induce a small conductivity that allows pyro-charges to dissipate. As the material gets more heavily treated, the capacity to dissipate charges improves, but the corresponding optical absorption also increases, causing insertion loss. Even though typical high gain targeting laser systems can tolerate a few percent of added loss, the thermo-chemical processing needs to be carefully optimized. We describe the results of our process optimization to minimize the insertion loss while still giving effective charge dissipation. Treatment is performed at temperatures below 500°C and a conductivity layer less than 0.5mm in depth is created that is uniform across the optical aperture. Because the conductivity is thermally activated, the charge dissipation is less effective at low temperature, and characterization needs to be performed at cold temperatures. The trade-off between optical insertion loss and potential depolarization due to low temperature operation is discussed and experimental results on the temperature dependence of the dissipation time and the

  13. Galactic cosmic-ray mediation of a spherical solar wind flow. 1: The steady state cold gas hydrodynamical approximation

    NASA Technical Reports Server (NTRS)

    Le Roux, J. A.; Ptuskin, V. S.

    1995-01-01

    Realistic models of the outer heliosphere should consider that the interstellar cosmic-ray pressure becomes comparable to pressures in the solar wind at distances more than 100 AU from the Sun. The cosmic-ray pressure dynamically affects solar wind flow through deceleration. This effect, which occurs over a scale length of the order of the effective diffusion length at large radial distances, has important implications for cosmic-ray modulation and acceleration. As a first step toward solution of this nonlinear problem, a steady state numerical model was developed for a relatively cold spherical solar wind flow which encounters the confining isotropic pressure of the surrounding Galactic medium. This pressure is assumed to be dominated by energetic particles (Galactic cosmic rays). The system of equations, which are solved self-consistently, includes the relevant hydrodynamical equations for the solar wind flow and the spherical cosmic-ray transport equation. To avoid the closure parameter problem of the two-fluid model, the latter equation is solved for the energy-dependent cosmic-ray distribution function.

  14. Cold neutron tomography of annular coolant flow in a double subchannel model of a boiling water reactor

    NASA Astrophysics Data System (ADS)

    Kickhofel, J. L.; Zboray, R.; Damsohn, M.; Kaestner, A.; Lehmann, E. H.; Prasser, H.-M.

    2011-09-01

    Dryout of the liquid coolant film on fuel pins at the top of boiling water reactor (BWR) cores constitutes the type of heat transfer crisis relevant for the conditions of high void fractions. It is a limiting factor in the thermal power, and therefore the economy, of BWRs. Ongoing research on multiphase annular flow, specifically the liquid film thickness, is fundamental not only to nuclear reactor safety and operation but also to that of evaporators, condensers, and pipelines in a general industrial context. We have performed cold neutron tomography of adiabatic air water annular flow in a scaled up model of the subchannel geometry found in BWR fuel assemblies today. All imaging has been performed at the ICON beamline at the neutron spallation source SINQ at the Paul Scherrer Institut in Switzerland. Neutron tomography is shown to excel in investigating the interactions of air water two phase flows with spacer vanes of different geometry. The high resolution, high contrast measurements provide spatial distributions of the coolant on top of the surfaces of the spacer, including the vanes, and in the subchannel downstream of the spacers.

  15. Determination of total mercury in environmental and biological samples by flow injection cold vapour atomic absorption spectrometry

    NASA Astrophysics Data System (ADS)

    Murphy, James; Jones, Phil; Hill, Steve J.

    1996-12-01

    A simple and accurate method has been developed for the determination of total mercury in environmental and biological samples. The method utilises an off-line microwave digestion stage followed by analysis using a flow injection system with detection by cold vapour atomic absorption spectrometry. The method has been validated using two certified reference materials (DORM-1 dogfish and MESS-2 estuarine sediment) and the results agreed well with the certified values. A detection limit of 0.2 ng g -1 Hg was obtained and no significant interference was observed. The method was finally applied to the determination of mercury in river sediments and canned tuna fish, and gave results in the range 0.1-3.0 mg kg -1.

  16. Cold-flow acoustic evaluation of a small scale, divergent, lobed nozzle for supersonic jet noise suppression

    NASA Technical Reports Server (NTRS)

    Huff, R. G.; Groesbeck, D. E.

    1975-01-01

    A supersonic jet noise suppressor was tested with cold flow for acoustic and thrust characteristics at nozzle- to atmospheric-pressure ratios of 1.5 to 4.0. Jet noise suppression and spectral characteristics of the divergent, lobed, suppressor (DLS) nozzle with and without an ejector are presented. Suppression was obtained at nozzle pressure ratios of 2.5 to 4.0. The largest, maximum-lobe, sound pressure level suppression with a hard-wall ejector was 14.6 decibels at a nozzle pressure ratio of 3.5. The thrust loss was 2 percent. In general, low-frequency jet noise was suppressed, leaving higher frequencies essentially unchanged. Without the ejector the nozzle showed a thrust loss of 11 percent together with slightly poorer noise suppression.

  17. Wing shielding of high velocity jet and shock-associated noise with cold and hot flow jets

    NASA Technical Reports Server (NTRS)

    Vonglahn, U.; Groesbeck, D.; Wagner, J.

    1976-01-01

    Jet exhaust noise shielding data are presented for cold and hot flows (ambient to 1,100 K) and pressure ratios from 1.7 to 2.75. A nominal 9.5-cm diameter conical nozzle was used with simple shielding surfaces that were varied in length from 28.8 to 114.3 cm. The nozzle was located 8.8 cm above the surfaces. The acoustic data with the various sheilding lengths are compared to each other and to that for the nozzle alone. In general, short shielding surfaces that provided shielding for subsonic jets did not provide as much shielding for jets with shock noise, however, long shielding surfaces did shield shock noise effectively.

  18. Wing shielding of high-velocity jet and shock-associated noise with cold and hot flow jets

    NASA Technical Reports Server (NTRS)

    Von Glahn, U.; Groesbeck, D.; Wagner, J.

    1976-01-01

    Jet exhaust noise shielding data are presented for cold and hot flows (ambient to 1100 K) and pressure ratios from 1.7 to 2.75. A nominal 9.5-cm diameter conical nozzle was used with simple shielding surfaces that were varied in length from 28.8 to 114.3 cm. The nozzle was located 8.8 cm above the surfaces. The acoustic data with the various shielding lengths are compared to each other and to that for the nozzle alone. In general, short shielding surfaces that provided shielding for subsonic jets did not provide as much shielding for jets with shock noise; however, long shielding surfaces did shield shock noise effectively.

  19. Wing shielding of high-velocity jet and shock-associated noise with cold and hot flow jets

    NASA Technical Reports Server (NTRS)

    Von Glahn, U.; Groesbeck, D.; Wagner, J.

    1976-01-01

    Jet exhaust noise shielding data are presented for cold and hot flows (ambient to 1100 K) and pressure ratios from 1.7 to 2.75. A nominal 9.5-cm diameter conical nozzle was used with simple shielding surfaces that were varied in length from 28.8 to 114.3 cm. The nozzle was located 8.8 cm above the surfaces. The acoustic data with the various shielding lengths are compared to each other and to that for the nozzle alone. In general, short shielding surfaces that provided shielding for subsonic jets did not provide as much shielding for jets with shock noise; however, long shielding surfaces did shield shock noise effectively.

  20. Concentration Measurements in a Cold Flow Model Annular Combustor Using Laser Induced Fluorescence

    NASA Technical Reports Server (NTRS)

    Morgan, Douglas C.

    1996-01-01

    A nonintrusive concentration measurement method is developed for determining the concentration distribution in a complex flow field. The measurement method consists of marking a liquid flow with a water soluble fluorescent dye. The dye is excited by a two dimensional sheet of laser light. The fluorescent intensity is shown to be proportional to the relative concentration level. The fluorescent field is recorded on a video cassette recorder through a video camera. The recorded images are analyzed with image processing hardware and software to obtain intensity levels. Mean and root mean square (rms) values are calculated from these intensity levels. The method is tested on a single round turbulent jet because previous concentration measurements have been made on this configuration by other investigators. The previous results were used to comparison to qualify the current method. These comparisons showed that this method provides satisfactory results. 'Me concentration measurement system was used to measure the concentrations in the complex flow field of a model gas turbine annular combustor. The model annular combustor consists of opposing primary jets and an annular jet which discharges perpendicular to the primary jets. The mixing between the different jet flows can be visualized from the calculated mean and rms profiles. Concentration field visualization images obtained from the processing provide further qualitative information about the flow field.

  1. An improved stochastic separated flow model for turbulent two-phase flow

    NASA Astrophysics Data System (ADS)

    Chan, C. K.; Zhang, H. Q.; Lau, K. S.

    An improved stochastic separated flow model is proposed to obtain reasonable statistical characteristics of a two-phase flow. Effects of the history of a particle and its current trajectory position on the mean-square fluctuating velocity of the dispersed phase are continuously considered in this model. Comparing with the conventional model, results using the improved model are more reasonable and can also be obtained more easily. Furthermore, the improved model requires less computational particles for simulating dispersed-phase turbulence at the beginning of the stochastic trajectory. In this paper, an application in turbulent two-phase flow of planar mixing layer is carried out. Numerical results including velocity, mean-square fluctuating velocity, particle number density and pdf of fluctuation velocity of dispersed phase are shown to compare well with experimental data.

  2. Velocity control for improving flow through a bottleneck

    NASA Astrophysics Data System (ADS)

    Yamamoto, Hiroki; Yanagisawa, Daichi; Nishinari, Katsuhiro

    2017-04-01

    A bottleneck can largely deteriorate the flow, such as a traffic light or an on-ramp at a road. To alleviate bottleneck situations, one of the important strategies is to control input rate to suit the state of the road. In this study, we propose an effective velocity control of traveling particles, in which the particle velocity depends on the state of a bottleneck. To analyze our method, we modify the totally asymmetric simple exclusion process (TASEP) and introduce a slow-to-start rule, which we refer to as controlled TASEP in the present paper. Flow improvement is verified in numerical simulations and theoretical analyses by using controlled TASEP.

  3. Improvement of hydrogen storage properties of magnesium alloys by cold rolling and forging

    NASA Astrophysics Data System (ADS)

    Huot, Jacques; Amira, Sofiene; Lang, Julien; Skryabina, Nataliya; Fruchart, Daniel

    2014-08-01

    In this talk we show that cold rolling (CR) could be used to enhance hydrogen sorption properties of magnesium and magnesium alloys. In particular, cold rolling could reduce the first hydrogenation time, the so-called activation. Pure magnesium, commercial AZ91D alloy, and an experimental creep resistant magnesium alloy MRI153 in the as-cast and die-cast states were investigated. We found that both MRI and AZ91 alloys present faster activation kinetic than pure magnesium. This could be explained by the texture, higher number of defects, and nanostructure in CR materials but also precipitates at the grain boundaries. The effect of filing was also investigated.

  4. Cold stress improves the ability of Lactobacillus plantarum L67 to survive freezing.

    PubMed

    Song, Sooyeon; Bae, Dong-Won; Lim, Kwangsei; Griffiths, Mansel W; Oh, Sejong

    2014-11-17

    The stress resistance of bacteria is affected by the physiological status of the bacterial cell and environmental factors such as pH, salts and temperature. In this study, we report on the stress response of Lactobacillus plantarum L67 after four consecutive freeze-thaw cycles. The cold stress response of the cold-shock protein genes (cspC, cspL and cspP) and ATPase activities were then evaluated. The cold stress was adjusted to 5 °C when the bacteria were growing at the mid-exponential phase. A comparative proteomic analysis was performed with two-dimensional gel electrophoresis (2D SDS-PAGE) and a matrix assisted laser desorption/ionization-mass spectrometer. Only 56% of the L. plantarum L67 cells without prior exposure to cold stress survived after four consecutive freeze-thaw cycles. However, 78% of the L. plantarum L67 cells that were treated with cold stress at 5 °C for 6 h survived after freeze-thaw conditions. After applying cold stress to the culture for 6h, the cells were then stored for 60 days at 5 °C, 25 °C and 35 °C separately. The cold-stressed culture of L. plantarum L67 showed an 8% higher viability than the control culture. After applying cold stress for 6h, the transcript levels of two genes (cspP and cspL) were up-regulated 1.4 (cspP) and 1.2 (cspL) times compared to the control. However, cspC was not up-regulated. A proteomic analysis showed that the proteins increased after a reduction of the incubation temperature to 5 °C. The importance of the expression of 13 other relevant proteins was also determined through the study. The exposure of L. plantarum cells to low temperatures aids their ability to survive through subsequent freeze-thaw processes and lyophilization.

  5. Plasma action on helium flow in cold atmospheric pressure plasma jet experiments

    NASA Astrophysics Data System (ADS)

    Darny, T.; Pouvesle, J.-M.; Fontane, J.; Joly, L.; Dozias, S.; Robert, E.

    2017-10-01

    In this work, helium flow modifications, visualized by schlieren imaging, induced by the plasma generated in a plasma jet have been studied in conditions used for biomedical treatments (jet being directed downwards with a low helium flow rate). It has been shown that the plasma action can shift up to few centimeters downstream the effects of buoyancy, which allows to the helium flow to reach a target below in conditions for which it is not the case when the plasma is off. This study reveals the critical role of large and long lifetime negative ions during repetitive operations in the kHz regime, inducing strong modifications in the gas propagation. The cumulative added streamwise momentum transferred to ambient air surrounding molecules resulting from a series of applied voltage pulses induces a gradual built up of a helium channel on tens of millisecond timescale. In some conditions, a remarkable stable cylindrical helium channel can be generated to the target with plasma supplied by negative polarity voltage pulses whereas a disturbed flow results from positive polarity operation. This has a direct effect on air penetration in the helium channel and then on the reactive species production over the target which is of great importance for biomedical applications. It has also been shown that with an appropriate combination of negative and positive polarity pulses, it is possible to benefit from both polarity features in order to optimize the plasma plume propagation and plasma delivery to a target.

  6. Coupled prediction of flood response and debris flow initiation during warm and cold season events in the Southern Appalachians, USA

    NASA Astrophysics Data System (ADS)

    Tao, J.; Barros, A. P.

    2013-07-01

    Debris flows associated with rainstorms are a frequent and devastating hazard in the Southern Appalachians in the United States. Whereas warm season events are clearly associated with heavy rainfall intensity, the same cannot be said for the cold season events. Instead, there is a relationship between large (cumulative) rainfall events independently of season, and thus hydrometeorological regime, and debris flows. This suggests that the dynamics of subsurface hydrologic processes play an important role as a trigger mechanism, specifically through soil moisture redistribution by interflow. The first objective of this study is to investigate this hypothesis. The second objective is to assess the physical basis for a regional coupled flood prediction and debris flow warning system. For this purpose, uncalibrated model simulations of well-documented debris flows in headwater catchments of the Southern Appalachians using a 3-D surface-groundwater hydrologic model coupled with slope stability models are examined in detail. Specifically, we focus on two vulnerable headwater catchments that experience frequent debris flows, the Big Creek and the Jonathan Creek in the Upper Pigeon River Basin, North Carolina, and three distinct weather systems: an extremely heavy summertime convective storm in 2011; a persistent winter storm lasting several days; and a severe winter storm in 2009. These events were selected due to the optimal availability of rainfall observations, availability of detailed field surveys of the landslides shortly after they occurred, which can be used to evaluate model predictions, and because they are representative of events that cause major economic losses in the region. The model results substantiate that interflow is a useful prognostic of conditions necessary for the initiation of slope instability, and should therefore be considered explicitly in landslide hazard assessments. Moreover, the relationships between slope stability and interflow are

  7. Analytical Tools to Improve Optimization Procedures for Lateral Flow Assays

    PubMed Central

    Hsieh, Helen V.; Dantzler, Jeffrey L.; Weigl, Bernhard H.

    2017-01-01

    Immunochromatographic or lateral flow assays (LFAs) are inexpensive, easy to use, point-of-care medical diagnostic tests that are found in arenas ranging from a doctor’s office in Manhattan to a rural medical clinic in low resource settings. The simplicity in the LFA itself belies the complex task of optimization required to make the test sensitive, rapid and easy to use. Currently, the manufacturers develop LFAs by empirical optimization of material components (e.g., analytical membranes, conjugate pads and sample pads), biological reagents (e.g., antibodies, blocking reagents and buffers) and the design of delivery geometry. In this paper, we will review conventional optimization and then focus on the latter and outline analytical tools, such as dynamic light scattering and optical biosensors, as well as methods, such as microfluidic flow design and mechanistic models. We are applying these tools to find non-obvious optima of lateral flow assays for improved sensitivity, specificity and manufacturing robustness. PMID:28555034

  8. Analytical Tools to Improve Optimization Procedures for Lateral Flow Assays.

    PubMed

    Hsieh, Helen V; Dantzler, Jeffrey L; Weigl, Bernhard H

    2017-05-28

    Immunochromatographic or lateral flow assays (LFAs) are inexpensive, easy to use, point-of-care medical diagnostic tests that are found in arenas ranging from a doctor's office in Manhattan to a rural medical clinic in low resource settings. The simplicity in the LFA itself belies the complex task of optimization required to make the test sensitive, rapid and easy to use. Currently, the manufacturers develop LFAs by empirical optimization of material components (e.g., analytical membranes, conjugate pads and sample pads), biological reagents (e.g., antibodies, blocking reagents and buffers) and the design of delivery geometry. In this paper, we will review conventional optimization and then focus on the latter and outline analytical tools, such as dynamic light scattering and optical biosensors, as well as methods, such as microfluidic flow design and mechanistic models. We are applying these tools to find non-obvious optima of lateral flow assays for improved sensitivity, specificity and manufacturing robustness.

  9. 15O PET Measurement of Blood Flow and Oxygen Consumption in Cold-Activated Human Brown Fat

    PubMed Central

    Muzik, Otto; Mangner, Thomas J.; Leonard, William R.; Kumar, Ajay; Janisse, James; Granneman, James G.

    2013-01-01

    Although it has been believed that brown adipose tissue (BAT) depots disappear shortly after the perinatal period in humans, PET imaging using the glucose analog 18F-FDG has shown unequivocally the existence of functional BAT in adult humans, suggesting that many humans retain some functional BAT past infancy. The objective of this study was to determine to what extent BAT thermogenesis is activated in adults during cold stress and to establish the relationship between BAT oxidative metabolism and 18F-FDG tracer uptake. Methods Twenty-five healthy adults (15 women and 10 men; mean age ± SD, 30 ± 7 y) underwent triple-oxygen scans (H215O, C15O, and 15O2) as well as measurements of daily energy expenditure (DEE; kcal/d) both at rest and after exposure to mild cold (15.5°C [60°F]) using indirect calorimetry. The subjects were divided into 2 groups (high BAT and low BAT) based on the presence or absence of 18F-FDG tracer uptake (standardized uptake value [SUV] > 2) in cervical–supraclavicular BAT. Blood flow and oxygen extraction fraction (OEF) were calculated from dynamic PET scans at the location of BAT, muscle, and white adipose tissue. Regional blood oxygen saturation was determined by near-infrared spectroscopy. The total energy expenditure during rest and mild cold stress was measured by indirect calorimetry. Tissue-level metabolic rate of oxygen (MRO2) in BAT was determined and used to calculate the contribution of activated BAT to DEE. Results The mass of activated BAT was 59.1 ± 17.5 g (range, 32–85 g) in the high-BAT group (8 women and 1 man; mean age, 29.6 ± 5.5 y) and 2.2 ± 3.6 g (range, 0–9.3 g) in the low-BAT group (9 men and 7 women; mean age, 31.4 ± 10 y). Corresponding maximal SUVs were significantly higher in the high-BAT group than in the low-BAT group (10.7 ± 3.9 vs. 2.1 ± 0.7, P = 0.01). Blood flow values were significantly higher in the high-BAT group than in the low-BAT group for BAT (12.9 ± 4.1 vs. 5.9 ± 2.2 mL/100 g/min, P = 0

  10. SRM Internal Flow Tests and Computational Fluid Dynamic Analysis. Volume 4; Cold Flow Analyses and CFD Analysis Capability Development

    NASA Technical Reports Server (NTRS)

    1995-01-01

    An evaluation of the effect of model inlet air temperature drift during a test run was performed to aid in the decision on the need for and/or the schedule for including heaters in the SRMAFTE. The Sverdrup acceptance test data was used to determine the drift in air temperature during runs over the entire range of delivered flow rates and pressures. The effect of this temperature drift on the model Reynolds number was also calculated. It was concluded from this study that a 2% change in absolute temperature during a test run could be adequately accounted for by the data analysis program. A handout package of these results was prepared and presented to ED35 management.

  11. Cold Calling and Web Postings: Do They Improve Students' Preparation and Learning in Statistics?

    ERIC Educational Resources Information Center

    Levy, Dan

    2014-01-01

    Getting students to prepare well for class is a common challenge faced by instructors all over the world. This study investigates the effects that two frequently used techniques to increase student preparation--web postings and cold calling--have on student outcomes. The study is based on two experiments and a qualitative study conducted in a…

  12. Application of COLD-PCR for improved detection of NF2 mosaic mutations.

    PubMed

    Paganini, Irene; Mancini, Irene; Baroncelli, Marta; Arena, Guido; Gensini, Francesca; Papi, Laura; Sestini, Roberta

    2014-07-01

    Somatic mosaicism represents the coexistence of two or more cell populations with different genotypes in one person, and it is involved in >30 monogenic disorders. Somatic mosaicism characterizes approximately 25% to 33% of patients with de novo neurofibromatosis type 2 (NF2). The identification of mosaicism is crucial to patients and their families because the clinical course of the disease and its transmission risk is influenced by the degree and distribution of mutated cells. Moreover, in NF2, the capability of discriminating patients with mosaicism is especially important to make differential diagnosis with schwannomatosis. However, the identification of mosaic variants is considerably difficult, and the development of specific molecular techniques to detect low levels of unknown molecular alterations is required. Co-amplification at lower denaturation temperature (COLD)-PCR has been described as a powerful method to selectively amplify minority alleles from mixtures of wild-type and mutation-containing sequences. Here, we applied COLD-PCR to molecular analysis of patients with NF2 mosaicism. With the use of COLD-PCR, followed by direct sequencing, we were able to detect NF2 mutations in blood DNA of three patients with NF2 mosaicism. Our study has shown the capability of COLD-PCR in enriching low-represented mutated allele in blood DNA sample, making it usable for molecular diagnosis of patients with mosaicism.

  13. Effective dynamics of cold atoms flowing in two ring-shaped optical potentials with tunable tunneling

    NASA Astrophysics Data System (ADS)

    Aghamalyan, Davit; Amico, Luigi; Kwek, L. C.

    2013-12-01

    We study the current dynamics of coupled atomic condensates flowing in two ring-shaped optical potentials. We provide a specific setup where the ring-ring coupling can be tuned in an experimentally feasible way. It is demonstrated that the imaginary time effective action of the system in a weak coupling regime provides a two-level-system dynamics for the phase slip across the two rings. Through two-mode Gross- Pitaevskii mean-field equations, the real-time dynamics of the population imbalance and the phase difference between the two condensates is thoroughly analyzed analytically, as a function of the relevant physical parameters of the system. In particular, we find that the macroscopic quantum self-trapping phenomenon is induced in the system if the flowing currents assume a nonvanishing difference.

  14. Shear flow control of cold and heated rectangular jets by mechanical tabs. Volume 2: Tabulated data

    NASA Technical Reports Server (NTRS)

    Brown, W. H.; Ahuja, K. K.

    1989-01-01

    The effects of mechanical protrusions on the jet mixing characteristics of rectangular nozzles for heated and unheated subsonic and supersonic jet plumes were studied. The characteristics of a rectangular nozzle of aspect ratio 4 without the mechanical protrusions were first investigated. Intrusive probes were used to make the flow measurements. Possible errors introduced by intrusive probes in making shear flow measurements were also examined. Several scaled sizes of mechanical tabs were then tested, configured around the perimeter of the rectangular jet. Both the number and the location of the tabs were varied. From this, the best configuration was selected. This volume contains tabulated data for each of the data runs cited in Volume 1. Baseline characteristics, mixing modifications (subsonic and supersonic, heated and unheated) and miscellaneous charts are included.

  15. Improving wind turbine array efficiency through active flow control

    NASA Astrophysics Data System (ADS)

    Velarde, John-Michael; Wang, Guannan; Shea, Patrick; Glauser, Mark; Castillo, Luciano

    2013-11-01

    We attempted to demonstrate the capability of instrumenting three wind turbine blades with an air delivery system that provided active flow control in an effort to improve turbine performance in the presence of the wake turbulence that is inherent in a turbine array. Presently, turbines are being designed for set conditions, such as steady incoming wind and a set velocity profile, however conditions can be drastically different in the field - thus causing poor performance from the turbines. The blades were instrumented with pressure transducers which measured the suction surface pressure; the sensor setup was such that three unique blade configurations existed: spanwise sensors, chord-wise sensors, and a reference sensor. The compressed air was delivered through a rotary union connected to the turbine hub with tubing attached to the suction side of the blades. The primary purpose of this test was to demonstrate the ability to deliver air to a rotating frame for active flow control. We collected data under three test conditions using an open-section wind tunnel, courtesy of Texas Tech University: static with no flow control, rotation with no flow control, and rotation with active flow control.

  16. NASA Ares I Launch Vehicle Upper Stage Reaction Control System (ReCS) Cold Flow Development Test Overview

    NASA Technical Reports Server (NTRS)

    Dervan, Melanie; Williams, Hunter; Holt, Kim; Sivak, Amy; Morris, Jon D.

    2010-01-01

    NASA s Ares I launch vehicle, consisting of a five segment solid rocket booster first stage and a liquid bi-propellant J2-X engine Upper Stage, is the vehicle that s been chosen to launch the Orion Crew Module, which will return humans to the Moon, Mars, and beyond. After First Stage booster separation, the Reaction Control System (ReCS), a monopropellant hydrazine system, will provide the Upper Stage element with three degrees of freedom control as needed. This paper provides an overview of the system level development testing that has taken place on the Ares I launch vehicle Upper Stage ReCS. The ReCS System Development Test Article (SDTA) was built as a flight representative water flow test article whose primary test objective was to obtain fluid system performance data to evaluate the integrate system performance characteristics and verify analytical models. Water is the industry standard for cold flow testing of hydrazine systems, because the densities are very close and the speeds of sound are well characterized. The completion of this development level test program was considered necessary to support the ReCS Critical Design Review. This paper will address the design approach taken in building the test article, the objectives of the test program, types of testing completed, general results, the ability of the program to meet the test objectives, and lessons learned

  17. Effects of K-Reactor pre-operational cold flow testing on total suspended solids in Pen Branch

    SciTech Connect

    Wilde, E.W.

    1991-12-01

    Total suspended solids (TSS) levels were monitored by SRL Environmental Sciences personnel at two locations in the Pen Branch Creek system in conjunction with K Reactor cold flow (pump) testing required as part of the reactor restart effort. The TSS data were compared with flow and rainfall data collected simultaneously in an effort to obtain insight on the suspension and movement for particulate material in the Pen Branch system in response to natural and operational causes. Pump testing clearly caused higher TSS levels at the two sampling locations. The artificially elevated TSS levels were more pronounced at a sampling location near the reactor than at a sampling location farther downstream. Although the environmental data provided by this study were obtained and used exclusively for process control and research purposes, rather than for formal regulatory compliance (i.e. NPDES monitoring), the TSS levels determined by the comprehensive testing were compared with NPDES limits required at various SRS outfalls. TSS values in Pen Branch were seldom in excess of these limits. Because of the relatively few times that TSS values at the two sampling locations exceeded typical'' NPDES limits, and the fact that occasional relatively high TSS values could clearly be solely attributed to rainfall, it was concluded that no major adverse environmental impacts were caused to the Pen Branch system as a result of the K-Reactor pre-operational pump testing.

  18. Measurement Requirements for Improved Modeling of Arcjet Facility Flows

    NASA Technical Reports Server (NTRS)

    Fletcher, Douglas G.

    2000-01-01

    Current efforts to develop new reusable launch vehicles and to pursue low-cost robotic planetary missions have led to a renewed interest in understanding arc-jet flows. Part of this renewed interest is concerned with improving the understanding of arc-jet test results and the potential use of available computational-fluid- dynamic (CFD) codes to aid in this effort. These CFD codes have been extensively developed and tested for application to nonequilibrium, hypersonic flow modeling. It is envisioned, perhaps naively, that the application of these CFD codes to the simulation of arc-jet flows would serve two purposes: first. the codes would help to characterize the nonequilibrium nature of the arc-jet flows; and second. arc-jet experiments could potentially be used to validate the flow models. These two objectives are, to some extent, mutually exclusive. However, the purpose of the present discussion is to address what role CFD codes can play in the current arc-jet flow characterization effort, and whether or not the simulation of arc-jet facility tests can be used to eva1uate some of the modeling that is used to formu1ate these codes. This presentation is organized into several sections. In the introductory section, the development of large-scale, constricted-arc test facilities within NASA is reviewed, and the current state of flow diagnostics using conventional instrumentation is summarized. The motivation for using CFD to simulate arc-jet flows is addressed in the next section, and the basic requirements for CFD models that would be used for these simulations are briefly discussed. This section is followed by a more detailed description of experimental measurements that are needed to initiate credible simulations and to evaluate their fidelity in the different flow regions of an arc-jet facility. Observations from a recent combined computational and experiment.al investigation of shock-layer flows in a large-scale arc-jet facility are then used to illustrate the

  19. The Determination of Forces and Moments on a Gimballed SRM Nozzle Using a Cold Flow Model

    NASA Technical Reports Server (NTRS)

    Whitesides, R. Harold; Bacchus, David L.; Hengel, John E.

    1994-01-01

    The Solid Rocket Motor Air Flow Facility (SAF) at NASA Marshall Space Flight Center was used to characterize the flow in the critical aft end and nozzle of a solid propellant rocket motor (SRM) as part of the design phase of development. The SAF is a high pressure, blowdown facility which supplies a controlled flow of air to a subscale model of the internal port and nozzle of a SRM to enable measurement and evaluation of the flow field and surface pressure distributions. The ASRM Aft Section/Nozzle Model is an 8 percent scale model of the 19 second burn time aft port geometry and nozzle of the Advanced Solid Rocket Motor, the now canceled new generation space Shuttle Booster. It has the capability to simulate fixed nozzle gimbal angles of 0, 4, and 8 degrees. The model was tested at full scale motor Reynolds Numbers with extensive surface pressure instrumentation to enable detailed mapping of the surface pressure distributions over the nozzle interior surface, the exterior surface of the nozzle nose and the surface of the simulated propellant grain in the aft motor port. A mathematical analysis and associated numerical procedure were developed to integrate the measured surface pressure distributions to determine the lateral and axial forces on the moveable section of the nozzle, the effective model thrust and the effective aerodynamic thrust vector (as opposed to the geometric nozzle gimbal angle). The nozzle lateral and axial aerodynamic loads and moments about the pivot point are required for design purposes and require complex, three dimensional flow analyses. The alignment of the thrust vector with the nozzle geometric centerline is also a design requirement requiring three dimensional analyses which were supported by this experimental program. The model was tested with all three gimbal angles at three pressure levels to determine Reynolds number effects and reproducibility. This program was successful in demonstrating that a measured surface pressure

  20. Improved numerical methods for turbulent viscous recirculating flows

    NASA Technical Reports Server (NTRS)

    Turan, A.

    1985-01-01

    The hybrid-upwind finite difference schemes employed in generally available combustor codes possess excessive numerical diffusion errors which preclude accurate quantative calculations. The present study has as its primary objective the identification and assessment of an improved solution algorithm as well as discretization schemes applicable to analysis of turbulent viscous recirculating flows. The assessment is carried out primarily in two dimensional/axisymetric geometries with a view to identifying an appropriate technique to be incorporated in a three-dimensional code.

  1. EVIDENCE FOR COLD ACCRETION: PRIMITIVE GAS FLOWING ONTO A GALAXY AT z {approx} 0.274

    SciTech Connect

    Ribaudo, Joseph; Lehner, Nicolas; Christopher Howk, J.; Werk, Jessica K.; Xavier Prochaska, J.; Tumlinson, Jason

    2011-12-20

    We present UV and optical observations from the Cosmic Origins Spectrograph on the Hubble Space Telescope and Keck of a z = 0.27395 Lyman limit system (LLS) seen in absorption against the QSO PG1630+377. We detect H I absorption with log N(H I) = 17.06 {+-} 0.05 as well as Mg II, C III, Si III, and O VI in this system. The column densities are readily explained if this is a multi-phase system, with the intermediate and low ions arising in a very low metallicity ([Mg/H] = -1.71 {+-} 0.06) photoionized gas. We identify via Keck spectroscopy and Large Binocular Telescope imaging a 0.3 L{sub *} star-forming galaxy projected 37 kpc from the QSO at nearly identical redshift (z = 0.27406 and {Delta}v = -26 km s{sup -1}) with near solar metallicity ([O/H] = -0.20 {+-} 0.15). The presence of very low metallicity gas in the proximity of a near-solar metallicity, sub-L{sub *} galaxy strongly suggests that the LLS probes gas infalling onto the galaxy. A search of the literature reveals that such low-metallicity LLSs are not uncommon. We found that 50% (4/8) of the well-studied z {approx}< 1 LLSs have metallicities similar to the present system and show sub-L{sub *} galaxies with {rho} < 100 kpc in those fields where redshifts have been surveyed. We argue that the properties of these primitive LLSs and their host galaxies are consistent with those of cold mode accretion streams seen in galaxy simulations.

  2. Cellulose Nanocrystal Reinforced Chitosan Coatings for Improving the Storability of Postharvest Pears Under Both Ambient and Cold Storages.

    PubMed

    Deng, Zilong; Jung, Jooyeoun; Simonsen, John; Wang, Yan; Zhao, Yanyun

    2017-02-01

    Cellulose nanocrystal (CNC, 0%, 5%, and 10% w/w, in chitosan, dry basis) reinforced 2% chitosan aqueous coatings were evaluated for delaying the ripening and quality deterioration of postharvest green D'Anjou (Pyrus communis L.) and Bartlett (Pyrus communis L.) pears during 3 wk of ambient storage (20 ± 2 °C and 30 ± 2% RH) or 5 mo of cold storage (-1.1 °C and 90% RH), respectively. Ethylene and CO2 production, color, firmness, and internal fruit quality were monitored during both storage conditions. Moisture and gas barrier, antibacterial activity, and surface morphology of the derived films were also evaluated to investigate the mechanisms of delayed fruit ripening and quality deterioration. In the ambient storage study, the 5% CNC reinforced chitosan coating significantly (P < 0.05) delayed green chlorophyll degradation of pear peels, prevented internal browning, reduced senescence scalding, and improved retained fruit firmness. During cold storage, the 5% CNC reinforced chitosan coating showed a competitive effect on delaying fruit postharvest quality deterioration compared to a commercial product (Semperfresh™, Pace International, Wapato, Wash., U.S.A.). The 5% CNC coating strongly adhered to the pear surface, provided a superior gas barrier and a more homogenous matrix in comparison with the other coatings tested. Hence, it was effective in delaying ripening and improving the storability of postharvest pears during both ambient and cold storage. © 2017 Institute of Food Technologists®.

  3. Twelve-Hour Hypothermic Machine Perfusion for Donor Heart Preservation Leads to Improved Ultrastructural Characteristics Compared to Conventional Cold Storage.

    PubMed

    Michel, Sebastian G; La Muraglia, Glenn M; Madariaga, Maria Lucia L; Titus, James S; Selig, Martin K; Farkash, Evan A; Allan, James S; Anderson, Lisa M; Madsen, Joren C

    2015-08-11

    BACKGROUND Hypothermic machine perfusion of donor hearts has the theoretical advantage of continuous aerobic metabolism and washes out toxic metabolic byproducts. Here, we studied the effect of hypothermic machine perfusion on cardiac myocyte integrity when hearts are preserved for longer ischemic times (12 hours). MATERIAL AND METHODS Pig hearts were harvested and stored in Celsior® solution for 12 hours using either conventional cold storage on ice (12 h CS, n=3) or pulsatile perfusion with the Paragonix Sherpa Perfusion™ Cardiac Transport System at different flow rates (12 h PP, n=3 or 12 h PP low flow, n=2). After cold preservation, hearts were reperfused using an LV isovolumic Langendorff system. Controls (n=3) were reperfused immediately after organ harvest. Biopsies were taken from the apex of the left ventricle before storage, after storage and after reperfusion to measure ATP and endothelin-1 content in the tissue. TUNEL staining for signs of apoptosis and electron microscopy of the donor hearts were performed. RESULTS 12 h PP hearts showed significantly more weight gain than 12 h CS and controls after preservation. Pulsatile perfused hearts showed less ATP depletion, lower endothelin-1 levels and less apoptosis after preservation compared to CS. Electron microscopy showed damaged muscle fibers, endothelial cell rupture, and injury of mitochondria in the 12 h CS group, while machine perfusion could preserve the cell structures. CONCLUSIONS Hypothermic machine perfusion of donor hearts can preserve the cell structures better than conventional cold storage in prolonged ischemic times. Hypothermic pulsatile perfusion may therefore enable longer preservation times of donor hearts. Whether this method is able to avoid primary graft failure after orthotopic heart transplantation remains to be evaluated in further studies.

  4. A Global Approach to the Optimal Trajectory Based on an Improved Ant Colony Algorithm for Cold Spray

    NASA Astrophysics Data System (ADS)

    Cai, Zhenhua; Chen, Tingyang; Zeng, Chunnian; Guo, Xueping; Lian, Huijuan; Zheng, You; Wei, Xiaoxu

    2016-12-01

    This paper is concerned with finding a global approach to obtain the shortest complete coverage trajectory on complex surfaces for cold spray applications. A slicing algorithm is employed to decompose the free-form complex surface into several small pieces of simple topological type. The problem of finding the optimal arrangement of the pieces is translated into a generalized traveling salesman problem (GTSP). Owing to its high searching capability and convergence performance, an improved ant colony algorithm is then used to solve the GTSP. Through off-line simulation, a robot trajectory is generated based on the optimized result. The approach is applied to coat real components with a complex surface by using the cold spray system with copper as the spraying material.

  5. Cold physiology: postprandial blood flow dynamics and metabolism in the Antarctic fish Pagothenia borchgrevinki.

    PubMed

    Sandblom, Erik; Davison, William; Axelsson, Michael

    2012-01-01

    Previous studies on metabolic responses to feeding (i.e. the specific dynamic action, SDA) in Antarctic fishes living at temperatures below zero have reported long-lasting increases and small peak responses. We therefore hypothesized that the postprandial hyperemia also would be limited in the Antarctic fish Pagothenia borchgrevinki. The proportion of cardiac output directed to the splanchnic circulation in unfed fish was 18%, which is similar to temperate fish species. Contrary to our prediction, however, gastrointestinal blood flow had increased by 88% at twenty four hours after feeding due to a significant increase in cardiac output and a significant decrease in gastrointestinal vascular resistance. While gastric evacuation time appeared to be longer than in comparable temperate species, digestion had clearly commenced twenty four hours after feeding as judged by a reduction in mass of the administered feed. Even so, oxygen consumption did not increase suggesting an unusually slowly developing SDA. Adrenaline and angiotensin II was injected into unfed fish to investigate neuro-humoral control mechanisms of gastrointestinal blood flow. Both agonists increased gastrointestinal vascular resistance and arterial blood pressure, while systemic vascular resistance was largely unaffected. The hypertension was mainly due to increased cardiac output revealing that the heart and the gastrointestinal vasculature, but not the somatic vasculature, are important targets for these agonists. It is suggested that the apparently reduced SDA in P. borchgrevinki is due to a depressant effect of the low temperature on protein assimilation processes occurring outside of the gastrointestinal tract, while the gastrointestinal blood flow responses to feeding and vasoactive substances resemble those previously observed in temperate species.

  6. Patterns of subsurface fluid-flow at cold seeps: the Hikurangi Margin, offshore New Zealand

    NASA Astrophysics Data System (ADS)

    Krabbenhoeft, A.; Bialas, J.; Klaucke, I.; Crutchley, G. J.; Papenberg, C. A.; Netzeband, G. L.

    2012-12-01

    Based on multichannel seismic, geoacoustic, and methane sensor data, four different areas along the Hikurangi Margin show multiple indications for seep activity including bright spots, transparent zones, vertical chimneys, and the occurrence and distribution of bottom simulating reflectors. Locations where these features reach the seafloor are characterised by high backscatter intensity on sidescan sonar images and transparent zones in sediment echosounder profiles, while methane sensors show episodic, elevated methane concentrations near the seep sites. Methane discharge is facilitated by reduced hydrostatic pressure during low tides. The greatest number of seeps at Opouawe Bank correlates with the highest methane activity along the Hikurangi Margin. High heat flow values on flanks of ridges and low heat flow values on anticlines reflect a topographic effect on subsurface temperatures. Elevated heat flow occurs in the vicinity of seeps on Opouawe Bank. We propose that there are two drivers behind methane seepage with respect to the migration pathways of methane through the gas hydrate stability zone (GHSZ) to the seafloor: (1) structurally controlled and (2) stratigraphically controlled. In the structural model, vertical chimneys are the major pathways for methane through the GHSZ. Part of the upwardly migrating methane forms gas hydrate within the chimney. In the stratigraphic model, methane migration is stratigraphically controlled beneath seeps that are located on bathymetric highs and/or where subsurface anticlines occur beneath seeps. The structurally controlled seeps produce higher methane escape at the seafloor than those that are stratigraphically controlled. A combination of both driving mechanisms results in the highest methane seepage rates at the Tui Seep on Opouawe Bank.

  7. Imaging of flames and cold flows in air by diffraction from a laser-induced grating

    NASA Astrophysics Data System (ADS)

    Hemmerling, B.; Stampanoni-Panariello, A.

    1993-10-01

    Nonresonant laser-induced gratings are created in gases employing the second-harmonic output of a Nd: YAG laser in a degenerate four-wave mixing beam geometry. The diffraction efficiency of the gratings has been investigated as a function of laser intensity and gas pressure. Single-shot images of a helium flow in ambient air illustrate that diffraction of light from a laser-induced grating has the potential for remote, two-dimensional diagnostics of gas mixing processes. In addition, this coherent technique is used to image a sooty flame.

  8. Numerical Research on Magnetic Field, Temperature Field and Flow Field During Melting and Directionally Solidifying TiAl Alloys by Electromagnetic Cold Crucible

    NASA Astrophysics Data System (ADS)

    Chen, Ruirun; Yang, Yaohua; Gong, Xue; Guo, Jingjie; Su, Yanqing; Ding, Hongsheng; Fu, Hengzhi

    2017-08-01

    The electromagnetic cold crucible (EMCC) technique is an effective method to melt and directionally solidify reactive and high-temperature materials without contamination. The temperature field and fluid flow induced by the electromagnetic field are very important for melting and controlling the microstructure. In this article, a 3D EMCC model for calculating the magnetic field in the charges (TiAl alloys) using the T-Ω finite element method was established and verified. Magnetic fields in the charge under different electrical parameters, positions and dimensions of the charge were calculated and analyzed. The calculated results show that the magnetic field concentrates in the skin layer, and the magnetic flux density (B) increases with increasing of the frequency, charge diameter and current. The maximum B in the charge is affected by the position of the charge in EMCC (h 1) and the charge height (h 2), which emerges at the middle of coils (h c) when the relationship of h c < h 1 + h 2 < h c + δ is satisfied. Lower frequency and smaller charge diameter can improve the uniformity of the magnetic field in the charge. Consequently, the induced uniform electromagnetic stirring weakens the turbulence and improves temperature uniformity in the vicinity of the solid/liquid (S/L) interface, which is beneficial to forming a planar S/L interface during directional solidification. Based on the above conclusions, the TiAlNb alloy was successfully melted with lower power consumption and directionally solidified by the square EMCC.

  9. Cold-Climate Solar Domestic Hot Water Systems: Cost/Benefit Analysis and Opportunities for Improvement

    SciTech Connect

    Burch, J.; Hillman, T.; Salasovich, J.

    2005-01-01

    To determine potential for reduction in the cost of saved energy (COSE) for cold-climate solar domestic hot water (SDHW) systems, COSE was computed for three types of cold climate water heating systems. For each system, a series of cost-saving measures was considered: (1) balance of systems (BOS): tank, heat exchanger, and piping-valving measures; and (2) four alternative lower-cost collectors. Given all beneficial BOS measures in place, >50% reduction of COSE was achievable only with selective polymer collectors at half today's selective collector cost. In all three system types, today's metal-glass selective collector achieved the same COSE as the hypothesized non-selective polymer collector.

  10. Improving mechanical properties of polyethylene orthopaedic implants by high frequency cold plasma surface activation

    NASA Astrophysics Data System (ADS)

    Tudoran, Cristian D.; Vlad, Iulia E.; Dadarlat, Dorin N.; Anghel, Sorin D.

    2013-11-01

    Although a tremendous progress has been made in developing new methods and materials for manufacturing orthopaedic implants, the new technology still faces various problems. Polyethylene implants are relatively easy to manufacture and at lower cost compared to metallic or ceramic implants, but they present a fundamental problem: during usage and in time, due to their manufacturing technology, the material suffers from pitting and delamination which leads to crack propagation and finally to sudden fracture. Our studies and tests performed on polyethylene showed that, using cold plasma surface activation during the manufacturing process of the orthopaedic implants made from polyethylene can significantly increase their mechanical properties. The breaking tests revealed an increase of the tensile strength in the laminated polyethylene samples by a factor of 4 after plasma activation. "Aging" tests have been also performed to investigate how the cold plasma treated samples maintain their properties in time, after the surface activation process.

  11. Up-dosing with bilastine results in improved effectiveness in cold contact urticaria

    PubMed Central

    Krause, K; Spohr, A; Zuberbier, T; Church, M K; Maurer, M

    2013-01-01

    Background Cold contact urticaria (CCU) is characterized by itchy wheal and flare responses due to the release of histamine and other pro-inflammatory mediators after exposure to cold. The treatment of choice is nonsedating antihistamines, dosages of which may be increased up to fourfold if standard doses are ineffective. Here, we assess the effects of a standard 20 mg dose and up-dosing to 40 and 80 mg of bilastine in reducing the symptoms of CCU and inflammatory mediator release following cold challenge. Methods Twenty patients with CCU were included in this randomized, crossover, double-blind, placebo-controlled 12-week study. They received placebo, 20, 40 or 80 mg of bilastine daily each for 7 days with 14-day washout periods. The primary readout was change in critical temperature thresholds (CTT). Secondary readouts were changes in pruritus, levels of histamine IL-6, IL-8 and TNF-α collected by skin microdialysis and safety and tolerability of bilastine. Results Bilastine 20 mg was highly effective (P < 0.0001) in reducing CTT. Up-dosing to 80 mg significantly (P < 0.04) increased its effectiveness. At this dose, 19 of 20 (95%) patients responded to treatment, with 12 of 20 (60%) becoming symptom free. Only one patient was refractory to treatment. Microdialysis levels of histamine, IL-6 and IL-8 assessed 1–3 h after cold challenge were significantly (P < 0.05) decreased following up-dosing with 80 mg bilastine. Bilastine treat-ment was well tolerated without evidence of increased sedation with dose escala-tion. Conclusions Bilastine was effective in reducing the symptoms of patients with CCU. Increased efficacy of bilastine with fourfold up-dosing was without sedation and supports urticaria treatment guidelines. PMID:23742030

  12. Up-dosing with bilastine results in improved effectiveness in cold contact urticaria.

    PubMed

    Krause, K; Spohr, A; Zuberbier, T; Church, M K; Maurer, M

    2013-07-01

    Cold contact urticaria (CCU) is characterized by itchy wheal and flare responses due to the release of histamine and other pro-inflammatory mediators after exposure to cold. The treatment of choice is nonsedating antihistamines, dosages of which may be increased up to fourfold if standard doses are ineffective. Here, we assess the effects of a standard 20 mg dose and up-dosing to 40 and 80 mg of bilastine in reducing the symptoms of CCU and inflammatory mediator release following cold challenge. Twenty patients with CCU were included in this randomized, crossover, double-blind, placebo-controlled 12-week study. They received placebo, 20, 40 or 80 mg of bilastine daily each for 7 days with 14-day washout periods. The primary readout was change in critical temperature thresholds (CTT). Secondary readouts were changes in pruritus, levels of histamine IL-6, IL-8 and TNF-α collected by skin microdialysis and safety and tolerability of bilastine. Bilastine 20 mg was highly effective (P < 0.0001) in reducing CTT. Up-dosing to 80 mg significantly (P < 0.04) increased its effectiveness. At this dose, 19 of 20 (95%) patients responded to treatment, with 12 of 20 (60%) becoming symptom free. Only one patient was refractory to treatment. Microdialysis levels of histamine, IL-6 and IL-8 assessed 1-3 h after cold challenge were significantly (P < 0.05) decreased following up-dosing with 80 mg bilastine. Bilastine treatment was well tolerated without evidence of increased sedation with dose escalation. Bilastine was effective in reducing the symptoms of patients with CCU. Increased efficacy of bilastine with fourfold up-dosing was without sedation and supports urticaria treatment guidelines. © 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  13. Homeostatic Responses to Prolonged Cold Exposure: Human Cold Acclimatization

    DTIC Science & Technology

    1994-05-01

    cold acclimatization resulting from living and working in cold environments, and cold acclimation induced by unusual or experimental alterations in...reflects a greater thermal conductance resulting from increased metabolism, altered vasomotor responses, decreased physical insulation associated with low...vasoconstrictor response to cold is altered in circumpolar residents. For example, Brown and Page (9) measured hand blood flow in Inuits and

  14. Influence of Niobium on the Beginning of the Plastic Flow of Material during Cold Deformation

    PubMed Central

    2013-01-01

    Investigations were conducted on low-carbon steel and the steel with same chemical composition with addition of microalloying element niobium. While tensile testing was carried out, the thermographic measurement was tacking place simultaneously. A specific behavior of niobium microalloyed steel was noticed. Test results have shown that, in the elastic deformation region, thermoelastic effect occurs, which is more pronounced in niobium microalloyed steel. Start of plastic flow in steel which is not microalloyed with niobium begins later in comparison to the microalloyed steel, and it is conducted so that, at the point of maximum stress, deformation zone is formed within which stresses grow. In steel microalloyed with niobium after proportionality limit, comes the occurrence of the localized increase in temperature and the occurrence of Lüders band, which propagate along the sample forming a deformation zone. PMID:24453896

  15. Influence of niobium on the beginning of the plastic flow of material during cold deformation.

    PubMed

    Rešković, Stoja; Jandrlić, Ivan

    2013-01-01

    Investigations were conducted on low-carbon steel and the steel with same chemical composition with addition of microalloying element niobium. While tensile testing was carried out, the thermographic measurement was tacking place simultaneously. A specific behavior of niobium microalloyed steel was noticed. Test results have shown that, in the elastic deformation region, thermoelastic effect occurs, which is more pronounced in niobium microalloyed steel. Start of plastic flow in steel which is not microalloyed with niobium begins later in comparison to the microalloyed steel, and it is conducted so that, at the point of maximum stress, deformation zone is formed within which stresses grow. In steel microalloyed with niobium after proportionality limit, comes the occurrence of the localized increase in temperature and the occurrence of Lüders band, which propagate along the sample forming a deformation zone.

  16. Analysis of cold flow reestablishment time in a circuit breaker nozzle

    NASA Technical Reports Server (NTRS)

    Leone, S. A.; Nagamatsu, H. T.

    1983-01-01

    The deblocking process in a circuit breaker nozzle is similar to the flow starting process in a shock tunnel, and the computer uses this analogy to solve for the deblocking process by utilizing a diaphragm at the throat of a nozzle. At time equal to zero the diaphragm is broken and the throat area increases with time. It is a rarity to have the area as a function of both time and distance. Experimental data obtained from the RPI calibration shock tunnel are utilized to verify some of the calculated results with the area being a function of distance and the agreement is found to be good. The circuit breaker designer can utilize the computer simulation to estimate the deblocking time, an important parameter in the design of circuit breakers.

  17. An improved scheme for classifying susceptibility to preferential flow

    NASA Astrophysics Data System (ADS)

    Moeys, Julien; Koestel, John; Hollis, John M.; Jarvis, Nicholas J.

    2010-05-01

    The ability to reliably predict the occurrence and strength of preferential flow in different soils and land use systems would be of great benefit in environmental planning and management at multiple spatial scales, from field to catchments and regions. We recently proposed a simple classification scheme for predicting the susceptibility of soil horizons and pedons to macropore flow, designed to support predictive modelling (Jarvis N.J. et al., 2009. A conceptual model of soil susceptibility to macropore flow. Vadose Zone Journal, 8: 902-910). The scheme, which takes the form of a decision tree, was successfully validated against a small dataset of solute transport experiments. However, in its present form, it is strongly biased toward European agricultural soils, since it was developed to support pesticide risk assessment in the EU. In this poster, we propose an improved version of the classification scheme, which is much broader in scope, with relevance for a much wider range of soils worldwide, including those with clay mineralogies that limit the development of soil macro-structure and restrict macropore flow (e.g. Ferralsols and Andosols). The new scheme is tested in a literature meta-analysis exercise, making use of the temporal moments of solute breakthrough curves derived from fits of the mobile / immobile model to steady-state experiments on short laboratory columns.

  18. Mercury speciation in sea food by flow injection cold vapor atomic absorption spectrometry using selective solid phase extraction.

    PubMed

    Vereda Alonso, E; Siles Cordero, M T; García de Torres, A; Cañada Rudner, P; Cano Pavón, J M

    2008-10-19

    An on-line inorganic and organomercury species separation, preconcentration and determination system consisting of cold vapor atomic absorption spectrometry (CV-AAS or CV-ETAAS) coupled to a flow injection (FI) method was studied. The inorganic mercury species was retained on a column (i.d., 3 mm; length 3 cm) packed to a height of 0.7 cm with a chelating resin aminopropyl-controlled pore glass (550 A) functionalized with [1,5-bis (2 pyridyl)-3-sulphophenyl methylene thiocarbonohydrazyde] placed in the injection valve of a simple flow manifold. Methylmercury is not directly determined. Previous oxidation of the organomercurial species permitted the determination of total mercury. The separation of mercury species was obtained by the selective retention of inorganic mercury on the chelating resin. The difference between total and inorganic mercury determined the organomercury content in the sample. The inorganic mercury was removed on-line from the microcolumn with 6% (m/v) thiourea. The mercury cold vapor generation was performed on-line with 0.2% (m/v) sodium tethrahydroborate and 0.05% (m/v) sodium hydroxide as reducing solution. The determination was performed using CV-AAS and CV-ETAAS, both approaches have been used and compared for the speciation of mercury in sea food. A detection limit of 10 and 6 ng l(-1) was achieved for CV-AAS and CV-ETAAS, respectively. The precision for 10 replicate determinations at the 1 microg l(-1) Hg level was 3.5% relative standard deviation (R.S.D.), calculated from the peak heights obtained. Both approaches were validated with the use of two certified reference materials and by spiking experiments. By analyzing the two biological certified materials, it was evident that the difference between the total mercury and inorganic mercury corresponds to methylmercury. The concentrations obtained by both techniques were in agreement with the certified values or with differences of the certified values for total Hg(2+) and CH(3)Hg

  19. Effects of Blending Alcohols with Poultry Fat Methyl Esters on Cold Flow Properties

    USDA-ARS?s Scientific Manuscript database

    The low temperature operability, kinematic viscosity, and acid value of poultry fat methyl esters were improved with addition of ethanol, isopropanol, and butanol in a linear fashion with increasing alcohol content. The flash point decreased and moisture content increased upon addition of alcohols t...

  20. Improved Respiratory Navigator Gating for Thoracic 4D flow MRI

    PubMed Central

    van Ooij, Pim; Semaan, Edouard; Schnell, Susanne; Giri, Shivraman; Stankovic, Zoran; Carr, James; Barker, Alex J.; Markl, Michael

    2016-01-01

    Background Thoracic and abdominal 4D flow MRI is typically acquired in combination with navigator respiration control which can result in highly variable scan efficiency (Seff) and thus total scan time due to inter-individual variability in breathing patterns. The aim of this study was to test the feasibility of an improved respiratory control strategy based on diaphragm navigator gating with fixed Seff, respiratory driven phase encoding, and a navigator training phase. Methods 4D flow MRI of the thoracic aorta was performed in 10 healthy subjects at 1.5T and 3T systems for the in-vivo assessment of aortic time-resolved 3D blood flow velocities. For each subject, four 4D flow scans (1: conventional navigator gating, 2–4: new implementation with fixed Seff =60%, 80% and 100%) were acquired. Data analysis included semi-quantitative evaluation of image quality of the 4D flow magnitude images (image quality grading on a four point scale), 3D segmentation of the thoracic aorta, and voxel-by-voxel comparisons of systolic 3D flow velocity vector fields between scans. Results Conventional navigator gating resulted in variable Seff = 74±13% (range = 56% – 100%) due to inter-individual variability of respiration patterns. For scans 2–4, the the new navigator implementation was able to achieve predictable total scan times with stable Seff, only depending on heart rate. Semi- and fully quantitative analysis of image quality in 4D flow magnitude images was similar for the new navigator scheme compared to conventional navigator gating. For aortic systolic 3D velocities, good agreement was found between all new navigator settings (scan 2–4) with the conventional navigator gating (scan 1) with best performance for Seff = 80% (mean difference = −0.01; limits od agreement = 0.23, Pearson’s ρ=0.89, p <0.001). No significant differences for image quality or 3D systolic velocities were found for 1.5T compared to 3T. Conclusions The findings of this study demonstrate the

  1. A cold model experimental study on the flow characteristics of bed material in a fluidized bed bottom ash cooler in a CFB boiler

    NASA Astrophysics Data System (ADS)

    Lu, Xiaofeng; Li, Yourong

    2000-12-01

    A cold model experimental study on the flowing characteristics of bed material between a fluidized bed ash cooler and a furnace of CFB boiler were discussed in this paper. The research results showed that flowing status of the bed material in a bubbling bed, which was run with a circulating fluidized bed together in parallel operation, was influenced by the pressure difference between the CFB and the bubbling bed, the switch status of unlocking air, and the structure of the exit of the bubbling bed. There was a circulating flow of bed material between CFB and bubbling bed.

  2. Improving Advanced Inverter Control Convergence in Distribution Power Flow

    SciTech Connect

    Nagarajan, Adarsh; Palmintier, Bryan; Ding, Fei; Mather, Barry; Baggu, Murali

    2016-11-21

    Simulation of modern distribution system powerflow increasingly requires capturing the impact of advanced PV inverter voltage regulation on powerflow. With Volt/var control, the inverter adjusts its reactive power flow as a function of the point of common coupling (PCC) voltage. Similarly, Volt/watt control curtails active power production as a function of PCC voltage. However, with larger systems and higher penetrations of PV, this active/reactive power flow itself can cause significant changes to the PCC voltage potentially introducing oscillations that slow the convergence of system simulations. Improper treatment of these advanced inverter functions could potentially lead to incorrect results. This paper explores a simple approach to speed such convergence by blending in the previous iteration's reactive power estimate to dampen these oscillations. Results with a single large (5MW) PV system and with multiple 500kW advanced inverters show dramatic improvements using this approach.

  3. RuBisCO depletion improved proteome coverage of cold responsive S-nitrosylated targets in Brassica juncea

    PubMed Central

    Sehrawat, Ankita; Abat, Jasmeet K.; Deswal, Renu

    2013-01-01

    Although in the last few years good number of S-nitrosylated proteins are identified but information on endogenous targets is still limiting. Therefore, an attempt is made to decipher NO signaling in cold treated Brassica juncea seedlings. Treatment of seedlings with substrate, cofactor and inhibitor of Nitric-oxide synthase and nitrate reductase (NR), indicated NR mediated NO biosynthesis in cold. Analysis of the in vivo thiols showed depletion of low molecular weight thiols and enhancement of available protein thiols, suggesting redox changes. To have a detailed view, S-nitrosylation analysis was done using biotin switch technique (BST) and avidin-affinity chromatography. Ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisCO) is S-nitrosylated and therefore, is identified as target repeatedly due to its abundance. It also competes out low abundant proteins which are important NO signaling components. Therefore, RuBisCO was removed (over 80%) using immunoaffinity purification. Purified S-nitrosylated RuBisCO depleted proteins were resolved on 2-D gel as 110 spots, including 13 new, which were absent in the crude S-nitrosoproteome. These were identified by nLC-MS/MS as thioredoxin, fructose biphosphate aldolase class I, myrosinase, salt responsive proteins, peptidyl-prolyl cis-trans isomerase and malate dehydrogenase. Cold showed differential S-nitrosylation of 15 spots, enhanced superoxide dismutase activity (via S-nitrosylation) and promoted the detoxification of superoxide radicals. Increased S-nitrosylation of glyceraldehyde-3-phosphate dehydrogenase sedoheptulose-biphosphatase, and fructose biphosphate aldolase, indicated regulation of Calvin cycle by S-nitrosylation. The results showed that RuBisCO depletion improved proteome coverage and provided clues for NO signaling in cold. PMID:24032038

  4. Automated cold temperature cycling improves in vitro platelet properties and in vivo recovery in a mouse model compared to continuous cold storage.

    PubMed

    Skripchenko, Andrey; Gelderman, Monique P; Awatefe, Helen; Turgeon, Annette; Thompson-Montgomery, Dedeene; Cheng, Chunrong; Vostal, Jaroslav G; Wagner, Stephen J

    2016-01-01

    Platelets (PLTs) stored at cold temperatures (CTs) for prolonged time have dramatically reduced bacterial growth but poor survival when infused. A previous study demonstrated that human PLTs stored with manual cycling between 4 °C (12 hr) and 37 °C (30 min) and infused into severe combined immunodeficient (SCID) mice had survivals similar to or greater than those stored at room temperature (RT). In this study, the in vitro and in vivo properties of PLTs stored in an automated incubator programmed to cycle between 5 °C (11 hr) and 37 °C (1 hr) were evaluated. A Trima apheresis unit (n = 12) was aliquoted (60 mL) in CLX bags. One sample was stored with continuous agitation (RT), a second sample was stored at 4-6 °C without agitation (CT), and a third sample was placed in an automated temperature cycler with 5 minutes of agitation during the warm-up period (thermocycling [TC]). PLTs were assayed for several relevant quality variables. On Day 7, PLTs were infused into SCID mice and in vivo recovery was assessed at predetermined time points after transfusion. The glucose consumption rate, morphology score, hypotonic shock recovery level, and aggregation levels were increased and mitochondrial reactive oxygen species accumulations were decreased in TC-PLTs compared to those of CT-PLTs. The pH and Annexin V binding were comparable to those of RT-PLTs. All TC-PLTs had greater recovery than CT-PLTs and were comparable to RT-PLTs. PLTs stored under automated TC conditions have improved in vivo recovery and improved results for a number of in vitro measures compared to CT-PLTs. © 2015 AABB.

  5. Do water-saving technologies improve environmental flows?

    NASA Astrophysics Data System (ADS)

    Batchelor, Charles; Reddy, V. Ratna; Linstead, Conor; Dhar, Murli; Roy, Sumit; May, Rebecca

    2014-10-01

    Water saving and conservation technologies (WCTs) have been promoted widely in India as a practical means of improving the water use efficiency and freeing up water for other uses (e.g. for maintaining environmental flows in river systems). However, there is increasing evidence that, somewhat paradoxically, WCTs often contribute to intensification of water use by irrigated and rainfed farming systems. This occurs when: (1) Increased crop yields are coupled with increased consumptive water use and/or (2) Improved efficiency, productivity and profitability encourages farmers to increase the area cropped and/or to adopt multiple cropping systems. In both cases, the net effect is an increase in annual evapotranspiration that, particularly in areas of increasing water scarcity, can have the trade-off of reduced environmental flows. Recognition is also increasing that the claimed water savings of many WCTs may have been overstated. The root cause of this problem lies in confusion over what constitutes real water saving at the system or basin scales. The simple fact is that some of the water that is claimed to be ‘saved’ by WCTs would have percolated into the groundwater from where it can be and often is accessed and reused. Similarly, some of the “saved” runoff can be used downstream by, for example, farmers or freshwater ecosystems. This paper concludes that, particularly in areas facing increasing water scarcity, environmental flows will only be restored and maintained if they are given explicit (rather than theoretical or notional) attention. With this in mind, a simple methodology is proposed for deciding when and where WCTs may have detrimental impacts on environmental flows.

  6. Waterhammer Modeling for the Ares I Upper Stage Reaction Control System Cold Flow Development Test Article

    NASA Technical Reports Server (NTRS)

    Williams, Jonathan H.

    2010-01-01

    The Upper Stage Reaction Control System provides three-axis attitude control for the Ares I launch vehicle during active Upper Stage flight. The system design must accommodate rapid thruster firing to maintain the proper launch trajectory and thus allow for the possibility to pulse multiple thrusters simultaneously. Rapid thruster valve closure creates an increase in static pressure, known as waterhammer, which propagates throughout the propellant system at pressures exceeding nominal design values. A series of development tests conducted in the fall of 2009 at Marshall Space Flight Center were performed using a water-flow test article to better understand fluid performance characteristics of the Upper Stage Reaction Control System. A subset of the tests examined waterhammer along with the subsequent pressure and frequency response in the flight-representative system and provided data to anchor numerical models. This thesis presents a comparison of waterhammer test results with numerical model and analytical results. An overview of the flight system, test article, modeling and analysis are also provided.

  7. Nitrogen removal from wastewater by an aerated subsurface-flow constructed wetland in cold climates.

    PubMed

    Redmond, Eric D; Just, Craig L; Parkin, Gene F

    2014-04-01

    The objective of this study was to assess the role of cyclic aeration, vegetation, and temperature on nitrogen removal by subsurface-flow engineered wetlands. Aeration was shown to enhance total nitrogen and ammonia removal and to enhance removal of carbonaceous biochemical oxygen demand, chemical oxygen demand, and phosphorus. Effluent ammonia and total nitrogen concentrations were significantly lower in aerated wetland cells when compared with unaerated cells. There was no significant difference in nitrogen removal between planted and unplanted cells. Effluent total nitrogen concentrations ranged from 9 to 12 mg N/L in the aerated cells and from 23 to 24 mg N/L in unaerated cells. Effluent ammonia concentrations ranged from 3 to 7 mg N/L in aerated wetland cells and from 22 to 23 mg N/L in unaerated cells. For the conditions tested, temperature had only a minimal effect on effluent ammonia or total nitrogen concentrations. The tanks-in-series and the PkC models predicted the general trends in effluent ammonia and total nitrogen concentrations, but did not do well predicting short-term variability. Rate coefficients for aerated systems were 2 to 10 times greater than those for unaerated systems.

  8. Cyanobacterial Alkanes Modulate Photosynthetic Cyclic Electron Flow to Assist Growth under Cold Stress

    PubMed Central

    Berla, Bertram M.; Saha, Rajib; Maranas, Costas D.; Pakrasi, Himadri B.

    2015-01-01

    All cyanobacterial membranes contain diesel-range C15-C19 hydrocarbons at concentrations similar to chlorophyll. Recently, two universal but mutually exclusive hydrocarbon production pathways in cyanobacteria were discovered. We engineered a mutant of Synechocystis sp. PCC 6803 that produces no alkanes, which grew poorly at low temperatures. We analyzed this defect by assessing the redox kinetics of PSI. The mutant exhibited enhanced cyclic electron flow (CEF), especially at low temperature. CEF raises the ATP:NADPH ratio from photosynthesis and balances reductant requirements of biosynthesis with maintaining the redox poise of the electron transport chain. We conducted in silico flux balance analysis and showed that growth rate reaches a distinct maximum for an intermediate value of CEF equivalent to recycling 1 electron in 4 from PSI to the plastoquinone pool. Based on this analysis, we conclude that the lack of membrane alkanes causes higher CEF, perhaps for maintenance of redox poise. In turn, increased CEF reduces growth by forcing the cell to use less energy-efficient pathways, lowering the quantum efficiency of photosynthesis. This study highlights the unique and universal role of medium-chain hydrocarbons in cyanobacterial thylakoid membranes: they regulate redox balance and reductant partitioning in these oxygenic photosynthetic cells under stress. PMID:26459862

  9. Improvement in arousal, visual neglect, and perception of stimulus intensity following cold pressor stimulation.

    PubMed

    Woods, Adam J; Mennemeier, Mark; Garcia-Rill, Edgar; Huitt, Tiffany; Chelette, Kenneth C; McCullough, Gary; Munn, Tiffany; Brown, Ginger; Kiser, Thomas S

    2012-01-01

    The relationship between arousal, perception, and visual neglect was examined in this case study. Cold pressor stimulation (CPS: immersing the foot in iced water) was used to manipulate arousal and to determine its effects on contralesional neglect, perception of stimulus intensity (magnitude estimation), reaction time, and an electrophysiological correlate of ascending reticular activating system activity (i.e., the P50 potential). Measures that normalized from baseline following CPS included contralesional neglect on a clock drawing test, perception of stimulus magnitude, and P50 amplitude. The P50 amplitude returned to its abnormally low baseline level 20 min after CPS ended, indicating that CPS increased arousal.

  10. Extreme preconditioning: cold adaptation through sea swimming as a means to improving surgical outcomes.

    PubMed

    Harper, C Mark

    2012-04-01

    The practice of sea bathing for its health benefits was popularised by Richard Russell in Regency Brighton during the 18th Century. Although the cures he claimed it could effect seem a little far-fetched today, as with many historical remedies, there is much to be gained from revisiting such theories in the light of modern medical research. In this paper I will draw parallels between the surgical stress response and the response to cold exposure and hypothesise how a programme of sea bathing may be used to enhance postoperative recovery and reduce preoperative complications.

  11. An improved higher order panel method for linearized supersonic flow

    NASA Technical Reports Server (NTRS)

    Ehlers, F. E.; Epton, M. A.; Johnson, F. T.; Magnus, A. E.; Rubbert, P. E.

    1978-01-01

    An improved higher order panel method for linearized supersonic flow is described. Each panel, defined by four points on the surface, is divided into eight subpanels in such a way that all subpanel and panel edges are contiguous. By prescribing a quadratic distribution of the doublet on each subpanel, the doublet strength is made strictly continuous on the paneled surface. A linear source distribution is also used. Numerical results are smoother and in better agreement with experiment than the previous method with less strict continuity. A brief discussion of superinclined panels used to eliminate interior interference in nacelles is included.

  12. A significantly improved membrane for vanadium redox flow battery

    NASA Astrophysics Data System (ADS)

    Jia, Chuankun; Liu, Jianguo; Yan, Chuanwei

    A novel sandwich-type sulfonated poly(ether ether ketone) (SPEEK)/tungstophosphoric acid (TPA)/polypropylene (PP) composite membrane for a vanadium redox flow battery (VRB) has been developed with improved properties: the permeability of vanadium ions is greatly reduced and the performance of the VRB cell is greatly increased. The membrane is based on a traditional SPEEK membrane embedded with TPA but PP is used to enhance the membrane for the first time. Although its voltage efficiency (VE) is a little lower than that of a Nafion 212 membrane, it is expected to have good prospects for VRB systems because of its low cost and good performance.

  13. An improved higher order panel method for linearized supersonic flow

    NASA Technical Reports Server (NTRS)

    Ehlers, F. E.; Epton, M. A.; Johnson, F. T.; Magnus, A. E.; Rubbert, P. E.

    1978-01-01

    An improved higher order panel method for linearized supersonic flow is described. Each panel, defined by four points on the surface, is divided into eight subpanels in such a way that all subpanel and panel edges are contiguous. By prescribing a quadratic distribution of the doublet on each subpanel, the doublet strength is made strictly continuous on the paneled surface. A linear source distribution is also used. Numerical results are smoother and in better agreement with experiment than the previous method with less strict continuity. A brief discussion of superinclined panels used to eliminate interior interference in nacelles is included.

  14. Flow reduction in high-flow arteriovenous fistulas improve cardiovascular parameters and decreases need for hospitalization.

    PubMed

    Balamuthusamy, Saravanan; Jalandhara, Nishant; Subramanian, Anand; Mohanaselvan, Arvindselvan

    2016-07-01

    High output heart failure (HF) and pulmonary hypertension have been demonstrated in patients with prevalent arteriovenous (AV) fistulas. Fistulas with flow >2000 mL/minutes are more likely to induce changes in cardiac geometry and pulmonary artery pressure. The effects of reducing flow in AV access and its implications on HF decompensation and hospitalizations have not been studied. Retrospective analysis of 12 patients who needed hospitalization for acute Congestive Heart Failure (CHF) decompensation with AV access flow of 2 L/minutes (as defined by Kidney Disease Outcomes Quality Initiative (KDOQI)) or more were included in the study. All the patients underwent banding of their inflow at the anastomosis with perioperative access flow measurement. Follow-up period was 6 months. 2D echo was done at 6 months postbanding in addition to access flow and clinical evaluation. Complete data was available for all the 12 patients. Study data was collected on all the 12 patients. Mean age was 64.7 years. The mean access flow pre and postbanding were 3784 mL/minutes and 1178 mL/minutes, respectively (P < 0.001). Eighty percent of the patients had diabetes and 41% had coronary artery disease. There was a statistically significant decrease in cardiac output (pre = 7.06 L/minutes, post = 6.47 L/minutes P = 0.03), pulmonary systolic pressure (pre = 54 mmHg, post = 44 mmHg P = 0.02), left ventricular mass index (LVMI) (pre = 130 g/m(2) , post = 125 g/m(2) P = 0.006) and need for rehospitalization for CHF decompensation. The New York Heart Association (NYHA) staging improved by 1 stage postbanding (P = 0.002). The hospitalization rate was 3.75 ± 1.2 in the 6 months before banding and was decreased to 1.08 ± 1.2 (P = 0.002) postbanding. The hemoglobin level, predialysis systolic blood pressure, calcium phosphorous product and the use of Renin Angiotensin Aldosterone System (RAAS) blockade agents and calcium channel blockers

  15. Remote cooling circulator with cold valves

    NASA Astrophysics Data System (ADS)

    Raab, Jeff; Maddocks, James R.; Nguyen, Tanh; Toma, Glen; Tward, Emmanuel

    2012-06-01

    A fluid loop can be effective for cooling some distance from a pulse tube cooler or in applications that require vibration isolation from the cooled object. Space pulse tube coolers are very efficient, but like all regenerative high frequency Stirling and pulse tube coolers, the cold head needs to be located near the compressor in order to minimize the input power to the cooler. To provide the directional gas flow from the oscillating flow pulse tube cooler we added cold reed valves to the pulse tube cold block of our flight proven high efficiency cooler (HEC) so that cold gas could be circulated without the need for an additional circulation pump and additional heat exchangers to cool the gas. In this test an improved smaller cold valve than that previously reported was installed and the remote cooling and the parasitic heat loads were measured. The measurements are compared to those of our previously reported cold valve tests as well as warm reed valve tests that used a second circulator compressor and recuperative heat exchanger. The large improvement in remote cooling power relative to the previous cold valve tests will be described.

  16. Improvement through low cost biofilm carrier in anaerobic tubular digestion in cold climate regions.

    PubMed

    Martí-Herrero, J; Alvarez, R; Rojas, M R; Aliaga, L; Céspedes, R; Carbonell, J

    2014-09-01

    The aim of this research is to evaluate the increase of biogas production with low cost tubular digesters in cold climates using PET rings inside the reactor. Two similar digesters have been operated and monitored in cold weather conditions and have been fed with cow manure. Digester 1 was filled with PET - rings as a biofilm carrier, Digester 2 was kept as a reference. Through the PET - rings the functional surface could be increased by a factor 4.2. The results show that 44% more biogas per Kg SV has been produced with the biofilm carrier in use (0.33 m(3)/kg SV) (reference digester -0.23 m(3)/kg SV), at an organic load rate of 0.26 kg SV/m(3)/d. The thermal performance shows that with an adaptation of the low cost tubular digester the slurry temperature can be raised up to 16.6°C (average) by surrounding temperature of 6.1°C (average) without using any active heating system.

  17. Utilization of chemically modified pearl millet starches in preparation of custards with improved cold storage stability.

    PubMed

    Shaikh, Marium; Ali, Tahira Mohsin; Hasnain, Abid

    2017-11-01

    Custards were prepared using five ingredients: milk powder, modified pearl millet starch, sugar, vanilla essence and water. The effect of adding hydroxypropylated starch (HPS), succinylated starch (SUS), oxidised starch (OXS) and acetylated starch (ACS) on cold storage stability, pasting, textural and sensory properties was studied and compared to custards containing native pearl millet starch (NS). Interestingly, all chemically modified starches reduced syneresis and no water weeping was observed in custard sample incorporating hydroxypropylated starch (HPC) even after 7days of cold storage. Viscoamylographic analysis revealed that custard containing succinylated starch (SUC) had the highest peak viscosity (108.8 BU), whereas HPC showed the least set back viscosity (19.0 BU). Sensory results suggested that assessors preferred HPC over other custards. Custards are preferred for their chewy semi-solid texture. Incorporation of hydroxypropylated starch (HPS) increased hardness, gumminess and chewiness which subsequently led to higher sensory scores during subjective analysis. Also, no retrogradation peak was observed for HPS and acetylated starch (ACS) when rescanned after 14 days. Thus, it could be concluded that HPS could be used in custards to confer low temperature stability by reducing syneresis. Copyright © 2017 Elsevier B.V. All rights reserved.

  18. Flow visualization studies to improve the spiral pump design.

    PubMed

    Andrade, A; Biscegli, J; Sousa, J E; Ohashi, Y; Nosé, Y

    1997-07-01

    The spiral pump (SP) uses centrifugal and axial pumping principles simultaneously, through a conical shaped impeller with threads in its surface. Flow visualization studies were performed in critical areas of the SP. A closed circuit loop was filled with glycerin-water solution (40%). Amberlite particles (80 mesh) were illuminated by a planar helium-neon laser light (7 mW). The particle velocities were recorded with Kodak (TMAX-400) black and white film, and the flow behavior was studied with a micro video camera and color video printer. The flow visualization studies showed no turbulence or stagnant areas in the inlet and outlet ports of the SP. When using the impeller with one lead, at the top of the threads some recirculation appeared when the total pressure head increased. Two new impellers were made. One of them had the same conical shape with a thread having 2 leads. The second had a thread with 2 leads, but it also had a bigger cone angle. These modifications improved the pump hydrodynamic performance, decreasing the recirculation in pumping conditions that require pressures over 200 mm Hg.

  19. Coating microchannels to improve Field-Flow Fractionation

    NASA Astrophysics Data System (ADS)

    Shendruk, Tyler N.; Slater, Gary W.

    2011-03-01

    We propose a selective-steric-mode Field-Flow Fractionation (ssFFF) technique for size separation of particles. Grafting a dense polymer brush onto the accumulation wall of a microchannel adds two novel effects to FFF: the particles must pay an entropic cost to enter the brush and the brush has a hydrodynamic thickness that shifts the no-slip condition. For small particles, the brush acts as a low-velocity region, leading to chromatographic-like retention. We present an analytical retention theory for small but finite-sized particles in a microchannel with a dense Alexander brush coating that possesses a well-defined hydrodynamic thickness. This theory is compared to a numerical solution for the retention ratio given by a flow approximated by the Brinkman equation and particle-brush interaction that is both osmotic and compressional. Large performance improvements are predicted in several regimes. Multi-Particle Collision simulations of the system assess the impact of factors neglected by the theory such as the dynamics of particle impingement on the brush subject to a flow.

  20. Novel strategy to decrease reperfusion injuries and improve function of cold-preserved livers using normothermic ex vivo liver perfusion machine.

    PubMed

    Banan, Babak; Xiao, Zhenyu; Watson, Rao; Xu, Min; Jia, Jianluo; Upadhya, Gundumi A; Mohanakumar, Thalachallour; Lin, Yiing; Chapman, William

    2016-03-01

    Normothermic extracorporeal liver perfusion (NELP) can decrease ischemia/reperfusion injury to the greatest degree when cold ischemia time is minimized. Warm perfusion of cold-stored livers results in hepatocellular damage, sinusoidal endothelial cell (SEC) dysfunction, and Kupffer cell activation. However, the logistics of organ procurement mandates a period of cold preservation before NELP. The aim of this study was to determine the beneficial effects of gradual rewarming of cold-stored livers by placement on NELP. Three female porcine livers were used for each group. In the immediate NELP group, procured livers were immediately placed on NELP for 8 hours. In the cold NELP group, livers were cold-stored for 4 hours followed by NELP for 4 hours. In rewarming groups, livers were cold-stored for 4 hours, then gradually rewarmed in different durations to 38°C and kept on NELP for an additional 4 hours. For comparison purposes, the last 4 hours of NELP runs were considered to be the evaluation phase. Immediate NELP livers had significantly lower concentrations of liver transaminases, hyaluronic acid, and β-galactosidase and had higher bile production compared to the other groups. Rewarming livers had significantly lower concentrations of hyaluronic acid and β-galactosidase compared to the cold NELP livers. In addition, there was a significant decline in international normalized ratio values, improved bile production, reduced biliary epithelial cell damage, and improved cholangiocyte function. Thus, if a NELP machine is not available at the procurement site and livers will need to undergo a period of cold preservation, a gradual rewarming protocol before NELP may greatly reduce damages that are associated with reperfusion. In conclusion, gradual rewarming of cold-preserved livers upon NELP can minimize the hepatocellular damage, Kupffer cell activation, and SEC dysfunction.

  1. Exergy analysis of a counter flow Ranque-Hilsch vortex tube for different cold orifice diameters, L/D ratios and exit valve angles

    NASA Astrophysics Data System (ADS)

    Devade, Kiran D.; Pise, Ashok T.

    2016-12-01

    An experimental investigation is made to find out the effects of the cold end orifice diameters, length to diameter ratio and exit valve angles on the heating and cooling performance of the counter flow Ranque-Hilsch vortex tube with air as a working fluid. The tube and cold end orifices used at these experiments are made of brass. Three cold end orifices (5, 6 and 7 mm) have been manufactured and are used five different L/D ratios (15 plain tube, 15-18 with 4° divergence angle) and exit valve angles (30°-90°). Inlet pressures were adjusted from 200 to 600 kPa with 100 kPa increments, and the exergy loss, exergy efficiency was determined. As a result of the experimental study, it is determined that the exergy loss between the hot and cold fluid is decreased with increasing of the cold end orifice diameter. Exergy efficiency decreases with increase in L/D ratio. It is also concluded that diverging vortex tube produces lower exergy loss as compared to plain tube. Valve angles have significant effect on hot end exergy loss of the vortex tube.

  2. Towards an improved understanding of strength and anisotropy of cold compacted powder

    NASA Astrophysics Data System (ADS)

    Wang, Wenhai

    The strength of powder compacts after cold compaction is known to be anisotropic, which comes from the directionality of microstructure resulting from initial particle morphology and/or from particle deformation during compaction. Current work focuses on multi-scale numerical analysis of powder compaction with emphasis on the role of interparticle cohesion on post-compaction mechanical properties. At macroscopic level, we applied phenomenological model to describe the mechanical behavior of powder, in which the material is considered to be continuum medium. A user subroutine (VUMAT) was successfully developed for ABAQUS/Explicit analysis, in which one of the popular phenomenological models for powder compaction---Drucker Prager/Cap model---is implemented. By studying of pharmaceutical powder die compaction and subsequent diametrical compression test via finite element analysis, the capabilities and limitations of current constitutive models are evaluated on predicting such as density, stress and tool force evolution, as well as the strength and fracture tendency. Our results illustrate that current model has good predictive capability of powder densification (e.g. density evolution) but can not predict post-compaction strength well. The following studies focus on evaluating the physics and mechanics occurring at particle level. The compaction of granular media was explored by using MPFEM approach. In the new model, individual particles discretized with a finite element mesh allow for a full description of contact mechanics and local and global particle kinematics. The introduction of a layer of degrading material on the surface of each particle provides the means of introducing variable cohesion and its effect on the final strength of compacts. The simulations show that the unloading creates tensile stresses at the root of the contact necks, which may cause partial or full separation of contact interface when the cohesion developed during loading is not strong

  3. Cold Stress

    MedlinePlus

    ... Publications and Products Programs Contact NIOSH NIOSH COLD STRESS Recommend on Facebook Tweet Share Compartir Workers who ... cold environments may be at risk of cold stress. Extreme cold weather is a dangerous situation that ...

  4. Improving Emergency Department flow through optimized bed utilization.

    PubMed

    Chartier, Lucas Brien; Simoes, Licinia; Kuipers, Meredith; McGovern, Barb

    2016-01-01

    Over the last decade, patient volumes in the emergency department (ED) have grown disproportionately compared to the increase in staffing and resources at the Toronto Western Hospital, an academic tertiary care centre in Toronto, Canada. The resultant congestion has spilled over to the ED waiting room, where medically undifferentiated and potentially unstable patients must wait until a bed becomes available. The aim of this quality improvement project was to decrease the 90th percentile of wait time between triage and bed assignment (time-to-bed) by half, from 120 to 60 minutes, for our highest acuity patients. We engaged key stakeholders to identify barriers and potential strategies to achieve optimal flow of patients into the ED. We first identified multiple flow-interrupting challenges, including operational bottlenecks and cultural issues. We then generated change ideas to address two main underlying causes of ED congestion: unnecessary patient utilization of ED beds and communication breakdown causing bed turnaround delays. We subsequently performed seven tests of change through sequential plan-do-study-act (PDSA) cycles. The most significant gains were made by improving communication strategies: small gains were achieved through the optimization of in-house digital information management systems, while significant improvements were achieved through the implementation of a low-tech direct contact mechanism (a two-way radio or walkie-talkie). In the post-intervention phase, time-to-bed for the 90th percentile of high-acuity patients decreased from 120 minutes to 66 minutes, with special cause variation showing a significant shift in the weekly measurements.

  5. Improving Emergency Department flow through optimized bed utilization

    PubMed Central

    Chartier, Lucas Brien; Simoes, Licinia; Kuipers, Meredith; McGovern, Barb

    2016-01-01

    Over the last decade, patient volumes in the emergency department (ED) have grown disproportionately compared to the increase in staffing and resources at the Toronto Western Hospital, an academic tertiary care centre in Toronto, Canada. The resultant congestion has spilled over to the ED waiting room, where medically undifferentiated and potentially unstable patients must wait until a bed becomes available. The aim of this quality improvement project was to decrease the 90th percentile of wait time between triage and bed assignment (time-to-bed) by half, from 120 to 60 minutes, for our highest acuity patients. We engaged key stakeholders to identify barriers and potential strategies to achieve optimal flow of patients into the ED. We first identified multiple flow-interrupting challenges, including operational bottlenecks and cultural issues. We then generated change ideas to address two main underlying causes of ED congestion: unnecessary patient utilization of ED beds and communication breakdown causing bed turnaround delays. We subsequently performed seven tests of change through sequential plan-do-study-act (PDSA) cycles. The most significant gains were made by improving communication strategies: small gains were achieved through the optimization of in-house digital information management systems, while significant improvements were achieved through the implementation of a low-tech direct contact mechanism (a two-way radio or walkie-talkie). In the post-intervention phase, time-to-bed for the 90th percentile of high-acuity patients decreased from 120 minutes to 66 minutes, with special cause variation showing a significant shift in the weekly measurements. PMID:27752312

  6. An improved source flow characteristic technique for the analysis of scramjet exhaust flow fields

    NASA Technical Reports Server (NTRS)

    Delguidice, P. D.; Dash, S.

    1975-01-01

    The process is discussed of designing a nozzle for a hypersonic airbreathing vehicle which involves a complex study of the inter-relationship among many parameters: internal-external expansion, vehicle lift, drag, pitching moments, and structural and weight limitations. The source flow characteristic approach to the design process was extended and improved, and streamline interpolation procedure was incorporated. All characteristic and boundary calculations were made compatible with frozen, equilibrium and ideal gas thermodynamic options, while slip surface calculations (cowl interaction) were extended to underexpanded flow conditions. Since viscous forces can significantly influence vehicle forces, pitching moments and structural/weight considerations, a local integration via flat plate boundary layer skin friction and heat transfer coefficients was included. These effects are calculated using the Spalding and Chi method, and all force and moment calculations are performed via integration of the local forces acting on the specified vehicle wetted areas.

  7. Building America Best Practices Series: Volume 3; Builders and Buyers Handbook for Improving New Home Efficiency, Comfort, and Durability in Cold and Very Cold Climates

    SciTech Connect

    Not Available

    2005-08-01

    This best practices guide is part of a series produced by Building America. The guide book is a resource to help builders large and small build high-quality, energy-efficient homes that achieve 30% energy savings in space conditioning and water heating in the cold and very cold climates. The savings are in comparison with the 1993 Model Energy Code. The guide contains chapters for every member of the builder's team-from the manager to the site planner to the designers, site supervisors, the trades, and marketers. There is also a chapter for homeowners on how to use the book to provide help in selecting a new home or builder.

  8. Dynamic flow-driven erosion - An improved approximate solution

    NASA Astrophysics Data System (ADS)

    Yu, Bofu; Guo, Dawei; Rose, Calvin W.

    2017-09-01

    Rose et al. (2007) published an approximate solution of dynamic sediment concentration for steady and uniform flows, and this approximate solution shows a peak sediment concentration at the early stage of a runoff event, which can be used to describe and explain the first flush effect, a commonly observed phenomenon, especially in the urban environment. However the approximate solution does not converge to the steady state solution that is known exactly. The purpose of the note is to improve the approximate solution of Rose et al. (2007) by maintaining its functional form while forcing its steady state behaviour for sediment concentration to converge to the known steady state solution. The quality of the new approximate solution was assessed by comparing the new approximate solution with an exact solution for the single size class case, and with the numerical solution for the multiple size classes. It was found that 1) the relative error, or discrepancy, decreases as the stream power increases for all three soils considered; 2) the largest discrepancy occurs for the peak sediment concentration, and the average discrepancy in the peak concentration is less than 10% for the three soils considered; 3) for the majority of the 27 slope-flow combinations and for the three soils considered, the new approximate solution modestly underestimates the peak sediment concentration.

  9. Macrosegregation Improvement by Swirling Flow Nozzle for Bloom Continuous Castings

    NASA Astrophysics Data System (ADS)

    Sun, Haibo; Zhang, Jiaquan

    2014-06-01

    Based on mathematical model coupling electromagnetism, fluid flow, heat transfer, and solute transport, the metallurgical performances of conventional straight nozzle, swirling flow nozzle (SFN), and M-EMS have been evaluated and compared. The soundness improvement of bloom castings has been investigated by casting tests of adopting the newly designed SFN. As compared to the normal nozzle, center porosity has been eliminated along with the popular center radial crack, and a better chemical homogeneity was obtained by employing the SFN accordingly, where the maximum segregation degree of C and S at the strand cross section is decreased from 1.28 to 1.02 and from 1.32 to 1.06, respectively. Combined with the results of numerical simulation, the positive effect obtained can be attributed to the remarkable superheat dissipation under the implementation of SFN, where, compared with the normal nozzle, the melt superheat degree at the mold exit is reduced by 15.5 K, 9.8 K, and 17.3 K (15.5 °C, 9.8 °C, and 17.3 °C) under the other three casting measures of SFN, normal nozzle with M-EMS, and SFN with M-EMS, respectively.

  10. Branched-chain fatty acid methyl esters as cold flow improvers for biodiesel

    USDA-ARS?s Scientific Manuscript database

    Biodiesel is an alternative diesel fuel derived mainly from the transesterification of plant oils with methanol or ethanol. This fuel is generally made from commodity oils such as canola, palm, or soybean and has a number of properties that make it compatible in compression-ignition engines. Despite...

  11. Improving operative flow during pediatric airway evaluation: a quality-improvement initiative.

    PubMed

    Prager, Jeremy D; Ruiz, Amanda G; Mooney, Kristin; Gao, Dexiang; Szolnoki, Judit; Shah, Rahul K

    2015-03-01

    Microlaryngoscopy and bronchoscopy procedures (MLBs) are short-duration, high-acuity procedures that carry risk. Poor case flow and communication exacerbate such potential risk. Efficient operative flow is critical for patient safety and resource expenditure. To identify areas for improvement and evaluate the effectiveness of a multidisciplinary quality-improvement (QI) initiative. A QI project using the "Plan-Do-Study-Act" (PDSA) cycle was implemented to assess MLBs performed on pediatric patients in a tertiary academic children's hospital. Forty MLBs were audited using a QI evaluation tool containing 144 fields. Each MLB was evaluated for flow, communication, and timing. Opportunities for improvement were identified. Subsequently, QI interventions were implemented in an iterative cycle, and 66 MLBs were audited after the intervention. Specific QI interventions addressed issues of personnel frequently exiting the operating room (OR) and poor preoperative preparation, identified during QI audit as areas for improvement. Interventions included (1) conducting "huddles" between surgeon and OR staff to discuss needed equipment; (2) implementing improvements to surgeon case ordering and preference cards review; (3) posting an OR door sign to limit traffic during airway procedures; and (4) discouraging personnel breaks during airway procedures. Operating room exiting behavior of OR personnel, preoperative preparation, and case timing were assessed and compared before and after the QI intervention. Personnel exiting the OR during the MLB was identified as a preintervention issue, with the surgical technologist, circulator, or surgeon exiting the room in 55% of cases (n = 22). The surgical technologist and circulator left the room to retrieve equipment in 40% of cases (n = 16), which indicated the need for increased preoperative preparation to improve case timing and operative flow. The QI interventions implemented to address these concerns included education

  12. Automated continuous monitoring of inorganic and total mercury in wastewater and other waters by flow-injection analysis and cold-vapour atomic absorption spectrometry

    PubMed Central

    Birnie, S. E.

    1988-01-01

    An automated continuous monitoring system for the determination of inorganic and total mercury by flow-injection analysis followed by cold-vapour atomic absorption spectrometry is described. The method uses a typical flow-injection manifold where digestion and reduction of the injected sample takes place. Mercury is removed by aeration from the flowing stream in a specially designed air-liquid separator and swept into a silica cell for absorption measurement at a wavelength of 253.7 nm. A calibration curve up to 10 μg Hg ml-1 using three different path length cells is obtained with a detection limit of 0.02 μg Hg ml-1. The sampling rate of an injection every 3 min produces 20 results per hour from a flowing stream. PMID:18925201

  13. Overexpression of GhDof1 improved salt and cold tolerance and seed oil content in Gossypium hirsutum.

    PubMed

    Su, Ying; Liang, Wei; Liu, Zhengjie; Wang, Yumei; Zhao, Yanpeng; Ijaz, Babar; Hua, Jinping

    2017-07-28

    A homologous GhDof1, which belongs to a large family of plant-specific transcription factor DOF, was isolated from Upland cotton (Gossypium hirsutum L.). GhDof1 protein was located in the nucleus of onion epidermal cells, the core domain of transcriptional activity existed in the C-terminal, and the activity elements of GhDof1 promoter existed in the regions of -645∼ -469bp and -286∼ -132bp of transcriptional start codon. GhDof1 constitutively expressed in leaves, roots and stems, accumulated highest in leaves. The salinity and cold treatments induced GhDof1 transcript accumulation. The GhDof1-overexpressed cotton showed significantly higher salt and cold tolerance over the wild-type plants. Under salt stress, the root growth of overexpressed GhDof1 lines was promoted. The expression levels of stress-responsive genes, GhP5CS, GhSOD and GhMYB, were differently up-regulated in transgenic lines. Oil contents increased in some transgenic plants, and protein contents reduced compared with transformed receptor. These results suggested that GhDof1 was a functional transcription factor for improving the abiotic tolerance and seed oil content in Upland cotton. Copyright © 2017 Elsevier GmbH. All rights reserved.

  14. Improved preparation of small biological samples for mercury analysis using cold vapor atomic absorption spectroscopy.

    PubMed

    Adair, B M; Cobb, G P

    1999-05-01

    Concentrations of mercury in biological samples collected for environmental studies are often less than 0.1 microgram/g. Low mercury concentrations and small organ sizes in many wildlife species (approximately 0.1 g) increase the difficulty of mercury determination at environmentally relevant concentrations. We have developed a digestion technique to extract mercury from small (0.1 g), biological samples at these relevant concentrations. Mean recoveries (+/- standard error) from validation trials of mercury fortified tissue samples using cold vapor atomic absorption spectroscopy for analysis ranged from 102 +/- 4.3% (2.5 micrograms/L, n = 15) to 108 +/- 1.4% (25 micrograms/L, n = 15). Recoveries of inorganic mercury were 99 +/- 5 (n = 19) for quality assurance samples analyzed during environmental evaluations conducted during a 24 month period. This technique can be used to determine total mercury concentrations of 60 ng Hg/g sample. Samples can be analyzed in standard laboratories in a short time, at minimal cost. The technique is versatile and can be used to determine mercury concentrations in several different matrices, limiting the time and expense of method development and validation.

  15. Cold spray deposition of Ti2AlC coatings for improved nuclear fuel cladding

    NASA Astrophysics Data System (ADS)

    Maier, Benjamin R.; Garcia-Diaz, Brenda L.; Hauch, Benjamin; Olson, Luke C.; Sindelar, Robert L.; Sridharan, Kumar

    2015-11-01

    Coatings of Ti2AlC MAX phase compound have been successfully deposited on Zircaloy-4 (Zry-4) test flats, with the goal of enhancing the accident tolerance of LWR fuel cladding. Low temperature powder spray process, also known as cold spray, has been used to deposit coatings ∼90 μm in thickness using powder particles of <20 μm. X-ray diffraction analysis showed the phase-content of the deposited coatings to be identical to the powders indicating that no phase transformation or oxidation had occurred during the coating deposition process. The coating exhibited a high hardness of about 800 HK and pin-on-disk wear tests using abrasive ruby ball counter-surface showed the wear resistance of the coating to be significantly superior to the Zry-4 substrate. Scratch tests revealed the coatings to be well-adhered to the Zry-4 substrate. Such mechanical integrity is required for claddings from the standpoint of fretting wear resistance and resisting wear handling and insertion. Air oxidation tests at 700 °C and simulated LOCA tests at 1005 °C in steam environment showed the coatings to be significantly more oxidation resistant compared to Zry-4 suggesting that such coatings can potentially provide accident tolerance to nuclear fuel cladding.

  16. Improved adaptation to heat, cold, and solvent tolerance in Lactobacillus plantarum.

    PubMed

    Fiocco, D; Capozzi, V; Goffin, P; Hols, P; Spano, Giuseppe

    2007-12-01

    The effect of overproducing each of the three small heat shock proteins (Hsp; Hsp 18.5, Hsp 18.55, and Hsp 19.3) was investigated in Lactobacillus plantarum strain WCFS1. Overproduction of the three genes, hsp 18.5, hsp 18.55, and hsp 19.3, translationally fused to the start codon of the ldhL gene yielded a protein of approximately 19 kDa, as estimated from Tricine sodium dodecyl sulfate-polyacrylamide gel electrophoresis in agreement with the predicted molecular weight of small Hsps. Small Hsp overproduction alleviated the reduction in growth rate triggered by exposing exponentially growing cells to heat shock (37 or 40 degrees C) and cold shock (12 degrees C). Moreover, overproduction of Hsp 18.55 and Hsp 19.3 led to an enhanced survival in the presence of butanol (1% v/v) or ethanol (12% v/v) treatment suggesting a potential role of L. plantarum small Hsps in solvent tolerance.

  17. High-dose desloratadine decreases wheal volume and improves cold provocation thresholds compared with standard-dose treatment in patients with acquired cold urticaria: a randomized, placebo-controlled, crossover study.

    PubMed

    Siebenhaar, Frank; Degener, Franziska; Zuberbier, Torsten; Martus, Peter; Maurer, Marcus

    2009-03-01

    Increased dosing of nonsedating antihistamines is recommended by the current European Academy of Allergology and Clinical Immunology/Global Allergy and Asthma European Network/European Dermatology Forum guidelines on patients with acquired cold urticaria (ACU) who do not respond satisfactorily to the standard dose. Prospective data supporting this recommendation are scant. We sought to assess the effects of 5 and 20 mg of desloratadine and placebo on cold-induced urticarial reactions in patients with ACU. In this prospective, randomized, double-blind, 3-way crossover trial, patients with ACU (n = 30) received placebo, 5 mg of desloratadine, and 20 mg of desloratadine every day each for 7 days separated by 14-day washout periods. At the end of each treatment, patients underwent cold provocation with the TempTest 2.0/2.1 system, and urticarial reactions were assessed by using digital 3-dimensional time-lapse photography and thermography; the critical temperature threshold (CTT) and critical stimulation time threshold (CSTT) were measured. Adverse events (AEs) reported during the study were assessed. Compared with placebo, 7 days of desloratadine at 5 and 20 mg/d significantly reduced the volume of cold-induced wheals and areas of hyperthermic skin and improved CTT and CSTT results. Desloratadine at 20 mg/d significantly reduced cold-induced wheal volume and CTT and CSTT values versus desloratadine at 5 mg/d. Desloratadine was well tolerated, with no increased rate of somnolence or other AEs with 20 mg of desloratadine. Desloratadine at standard and high doses significantly improved objective signs of ACU provoked by cold exposure. Desloratadine at 4 times the standard dose significantly reduced ACU lesion severity versus 5 mg of desloratadine without an increase in AEs. This study supports current guidelines that increased desloratadine dosing might benefit patients with urticaria who do not respond to standard doses.

  18. Maintaining semen quality by improving cold chain equipment used in cattle artificial insemination

    NASA Astrophysics Data System (ADS)

    Lieberman, Daniel; McClure, Elizabeth; Harston, Stephen; Madan, Damian

    2016-06-01

    Artificial insemination of dairy cattle is a common practice in the developing world that can improve farmer incomes and food security. Maintaining the fertilizing potential of frozen semen as it is manipulated, transported and stored is crucial to the success of this process. Here we describe simple technological improvements to protect semen from inadvertent thermal fluctuations that occur when users mishandle semen using standard equipment. We show that when frozen semen is mishandled, characteristics of semen biology associated with fertility are negatively affected. We describe several design modifications and results from thermal performance tests of several improved prototypes. Finally, we compare semen that has been mishandled in standard and improved equipment. The data suggest that our canister improvements can better maintain characteristics of semen biology that correlate with fertility when it is mishandled.

  19. Maintaining semen quality by improving cold chain equipment used in cattle artificial insemination

    PubMed Central

    Lieberman, Daniel; McClure, Elizabeth; Harston, Stephen; Madan, Damian

    2016-01-01

    Artificial insemination of dairy cattle is a common practice in the developing world that can improve farmer incomes and food security. Maintaining the fertilizing potential of frozen semen as it is manipulated, transported and stored is crucial to the success of this process. Here we describe simple technological improvements to protect semen from inadvertent thermal fluctuations that occur when users mishandle semen using standard equipment. We show that when frozen semen is mishandled, characteristics of semen biology associated with fertility are negatively affected. We describe several design modifications and results from thermal performance tests of several improved prototypes. Finally, we compare semen that has been mishandled in standard and improved equipment. The data suggest that our canister improvements can better maintain characteristics of semen biology that correlate with fertility when it is mishandled. PMID:27313137

  20. Salicylic acid and methyl jasmonate improve chilling tolerance in cold-stored lemon fruit (Citrus limon).

    PubMed

    Siboza, Xolani Irvin; Bertling, Isa; Odindo, Alfred Oduor

    2014-11-15

    Chilling injury (CI) is associated with the degradation of membrane integrity which can be aligned to phenolic oxidation activated by polyphenol oxidase (PPO) and peroxidase (POD), enzymes responsible for tissue browning. Phenylalanine ammonia-lyase (PAL) is a further enzyme prominent in the phenolic metabolism that is involved in acclimation against chilling stress. It was hypothesized that treatment with methyl jasmonate (MJ) and salicylic acid (SA) may enhance chilling tolerance in lemon fruit by increasing the synthesis of total phenolics and PAL by activating the key enzyme regulating the shikimic acid pathway whilst inhibiting the activity of POD and PPO. Lemon fruit were treated with 10μM MJ, 2mM SA or 10μM MJ plus 2mM SA, waxed, stored at -0.5, 2 or 4.5°C for up to 28 days plus 7 days at 23°C. Membrane integrity was studied by investigating membrane permeability and the degree of membrane lipid peroxidation in lemon flavedo following cold storage. The 10μM MJ plus 2mM SA treatment was most effective in enhancing chilling tolerance of lemon fruit, significantly reducing chilling-induced membrane permeability and membrane lipid peroxidation of lemon flavedo tissue. This treatment also increased total phenolics and PAL activity in such tissue while inhibiting POD activity, the latter possibly contributing to the delay of CI manifestation. PPO activity was found to be a poor biochemical marker of CI. Treatment with 10μM MJ plus 2mM SA resulted in an alteration of the phenolic metabolism, enhancing chilling tolerance, possibly through increased production of total phenolics and the activation of PAL and inhibition of POD. Copyright © 2014 Elsevier GmbH. All rights reserved.

  1. Silica nanoparticles treated by cold atmospheric-pressure plasmas improve the dielectric performance of organic-inorganic nanocomposites.

    PubMed

    Yan, Wei; Han, Zhao Jun; Phung, B Toan; Ostrikov, Kostya Ken

    2012-05-01

    We report on the application of cold atmospheric-pressure plasmas to modify silica nanoparticles to enhance their compatibility with polymer matrices. Thermally nonequilibrium atmospheric-pressure plasma is generated by a high-voltage radio frequency power source operated in the capacitively coupled mode with helium as the working gas. Compared to the pure polymer and the polymer nanocomposites with untreated SiO(2), the plasma-treated SiO(2)-polymer nanocomposites show higher dielectric breakdown strength and extended endurance under a constant electrical stress. These improvements are attributed to the stronger interactions between the SiO(2) nanoparticles and the surrounding polymer matrix after the plasma treatment. Our method is generic and can be used in the production of high-performance organic-inorganic functional nanocomposites.

  2. Solution of plane cascade flow using improved surface singularity methods

    NASA Technical Reports Server (NTRS)

    Mcfarland, E. R.

    1981-01-01

    A solution method has been developed for calculating compressible inviscid flow through a linear cascade of arbitrary blade shapes. The method uses advanced surface singularity formulations which were adapted from those found in current external flow analyses. The resulting solution technique provides a fast flexible calculation for flows through turbomachinery blade rows. The solution method and some examples of the method's capabilities are presented.

  3. Development and Implementation of 3-D, High Speed Capacitance Tomography for Imaging Large-Scale, Cold-Flow Circulating Fluidized Bed

    SciTech Connect

    Marashdeh, Qussai

    2013-02-01

    A detailed understanding of multiphase flow behavior inside a Circulating Fluidized Bed (CFB) requires a 3-D technique capable of visualizing the flow field in real-time. Electrical Capacitance Volume Tomography (ECVT) is a newly developed technique that can provide such measurements. The attractiveness of the technique is in its low profile sensors, fast imaging speed and scalability to different section sizes, low operating cost, and safety. Moreover, the flexibility of ECVT sensors enable them to be designed around virtually any geometry, rendering them suitable to be used for measurement of solid flows in exit regions of the CFB. Tech4Imaging LLC has worked under contract with the U.S. Department of Energy's National Energy Technology Laboratory (DOE NETL) to develop an ECVT system for cold flow visualization and install it on a 12 inch ID circulating fluidized bed. The objective of this project was to help advance multi-phase flow science through implementation of an ECVT system on a cold flow model at DOE NETL. This project has responded to multi-phase community and industry needs of developing a tool that can be used to develop flow models, validate computational fluid dynamics simulations, provide detailed real-time feedback of process variables, and provide a comprehensive understating of multi-phase flow behavior. In this project, a complete ECVT system was successfully developed after considering different potential electronics and sensor designs. The system was tested at various flow conditions and with different materials, yielding real-time images of flow interaction in a gas-solid flow system. The system was installed on a 12 inch ID CFB of the US Department of Energy, Morgantown Labs. Technical and economic assessment of Scale-up and Commercialization of ECVT was also conducted. Experiments conducted with larger sensors in conditions similar to industrial settings are very promising. ECVT has also the potential to be developed for imaging multi

  4. Sympathetic ganglion transcutaneous electrical nerve stimulation after coronary artery bypass graft surgery improves femoral blood flow and exercise tolerance.

    PubMed

    Cipriano, Gerson; Neder, J Alberto; Umpierre, Daniel; Arena, Ross; Vieira, Paulo J C; Chiappa, Adriana M Güntzel; Ribeiro, Jorge P; Chiappa, Gaspar R

    2014-09-15

    We tested the hypothesis that transcutaneous electrical nerve stimulation (TENS) over the stellate ganglion region would reduce sympathetic overstimulation and improve femoral blood flow (FBF) after coronary artery bypass graft surgery. Thirty-eight patients (20 men, 24 New York Heart Association class III-IV) were randomized to 5-day postoperative TENS (n = 20; 4 times/day; 30 min/session) or sham TENS (n = 18) applied to the posterior cervical region (C7-T4). Sympathetic nervous system was stimulated by the cold pressor test, with FBF being measured by ultrasound Doppler. Femoral vascular conductance (FVC) was calculated as FBF/mean arterial pressure (MAP). Six-min walking distance established patients' functional capacity. Before and after the intervention periods, pain scores, opiate requirements, and circulating β-endorphin levels were determined. As expected, preoperative MAP increased and FBF and FVC decreased during the cold pressor test. Sham TENS had no significant effect on these variables (P > 0.05). In contrast, MAP decreased in the TENS group (125 ± 12 vs. 112 ± 10 mmHg). This finding, in association with a consistent increase in FBF (95 ± 5 vs. 145 ± 14 ml/min), led to significant improvements in FVC (P < 0.01). Moreover, 6-min walking distance improved only with TENS (postsurgery-presurgery = 35 ± 12 vs. 6 ± 10 m; P < 0.01). TENS was associated with lesser postoperative pain and opiate requirements but greater circulating β-endorphin levels (P < 0.05). In conclusion, stellate ganglion TENS after coronary artery bypass graft surgery positively impacted on limb blood flow during a sympathetic stimulation maneuver, a beneficial effect associated with improved clinical and functional outcomes.

  5. Analytical solutions for benchmarking cold regions subsurface water flow and energy transport models: One-dimensional soil thaw with conduction and advection

    NASA Astrophysics Data System (ADS)

    Kurylyk, Barret L.; McKenzie, Jeffrey M.; MacQuarrie, Kerry T. B.; Voss, Clifford I.

    2014-08-01

    Numerous cold regions water flow and energy transport models have emerged in recent years. Dissimilarities often exist in their mathematical formulations and/or numerical solution techniques, but few analytical solutions exist for benchmarking flow and energy transport models that include pore water phase change. This paper presents a detailed derivation of the Lunardini solution, an approximate analytical solution for predicting soil thawing subject to conduction, advection, and phase change. Fifteen thawing scenarios are examined by considering differences in porosity, surface temperature, Darcy velocity, and initial temperature. The accuracy of the Lunardini solution is shown to be proportional to the Stefan number. The analytical solution results obtained for soil thawing scenarios with water flow and advection are compared to those obtained from the finite element model SUTRA. Three problems, two involving the Lunardini solution and one involving the classic Neumann solution, are recommended as standard benchmarks for future model development and testing.

  6. Analytical solutions for benchmarking cold regions subsurface water flow and energy transport models: one-dimensional soil thaw with conduction and advection

    USGS Publications Warehouse

    Kurylyk, Barret L.; McKenzie, Jeffrey M; MacQuarrie, Kerry T. B.; Voss, Clifford I.

    2014-01-01

    Numerous cold regions water flow and energy transport models have emerged in recent years. Dissimilarities often exist in their mathematical formulations and/or numerical solution techniques, but few analytical solutions exist for benchmarking flow and energy transport models that include pore water phase change. This paper presents a detailed derivation of the Lunardini solution, an approximate analytical solution for predicting soil thawing subject to conduction, advection, and phase change. Fifteen thawing scenarios are examined by considering differences in porosity, surface temperature, Darcy velocity, and initial temperature. The accuracy of the Lunardini solution is shown to be proportional to the Stefan number. The analytical solution results obtained for soil thawing scenarios with water flow and advection are compared to those obtained from the finite element model SUTRA. Three problems, two involving the Lunardini solution and one involving the classic Neumann solution, are recommended as standard benchmarks for future model development and testing.

  7. COUNTERCURRENT FLOW LIMITATION EXPERIMENTS AND MODELING FOR IMPROVED REACTOR SAFETY

    SciTech Connect

    Vierow, Karen

    2008-09-26

    This project is investigating countercurrent flow and “flooding” phenomena in light water reactor systems to improve reactor safety of current and future reactors. To better understand the occurrence of flooding in the surge line geometry of a PWR, two experimental programs were performed. In the first, a test facility with an acrylic test section provided visual data on flooding for air-water systems in large diameter tubes. This test section also allowed for development of techniques to form an annular liquid film along the inner surface of the “surge line” and other techniques which would be difficult to verify in an opaque test section. Based on experiences in the air-water testing and the improved understanding of flooding phenomena, two series of tests were conducted in a large-diameter, stainless steel test section. Air-water test results and steam-water test results were directly compared to note the effect of condensation. Results indicate that, as for smaller diameter tubes, the flooding phenomena is predominantly driven by the hydrodynamics. Tests with the test sections inclined were attempted but the annular film was easily disrupted. A theoretical model for steam venting from inclined tubes is proposed herein and validated against air-water data. Empirical correlations were proposed for air-water and steam-water data. Methods for developing analytical models of the air-water and steam-water systems are discussed, as is the applicability of the current data to the surge line conditions. This report documents the project results from July 1, 2005 through June 30, 2008.

  8. Improved macroscopic traffic flow model for aggressive drivers

    SciTech Connect

    Mendez, A. R.; Velasco, R. M.

    2011-03-24

    As has been done for the treatment of diluted gases, kinetic methods are formulated for the study of unidirectional freeway traffic. Fluid dynamic models obtained from kinetic equations have inherent restrictions, the principal one is the restriction to the low density regime. Macroscopic models obtained from kinetic equations tends to selfrestrict to this regime and makes impossible to observe the medium density region. In this work, we present some results heading to improve this model and extend the observable region. Now, we are presenting a fluid dynamic model for aggressive drivers obtained from kinetic assumptions to extend the model to the medium density region in order to study synchronization phenomena which is a very interesting transition phase between free flow and traffic jams. We are changing the constant variance prefactor condition imposed before by a variance prefactor density dependent, the numerical solution of the model is presented, analyzed and contrasted with the previous one. We are also comparing our results with heuristic macroscopic models and real traffic observations.

  9. Investigation of CO2 capture using solid sorbents in a fluidized bed reactor: Cold flow hydrodynamics

    SciTech Connect

    Li, Tingwen; Dietiker, Jean -Francois; Rogers, William; Panday, Rupen; Gopalan, Balaji; Breault, Greggory

    2016-07-29

    Both experimental tests and numerical simulations were conducted to investigate the fluidization behavior of a solid CO2 sorbent with a mean diameter of 100 μm and density of about 480 kg/m, which belongs to Geldart's Group A powder. A carefully designed fluidized bed facility was used to perform a series of experimental tests to study the flow hydrodynamics. Numerical simulations using the two-fluid model indicated that the grid resolution has a significant impact on the bed expansion and bubbling flow behavior. Due to the limited computational resource, no good grid independent results were achieved using the standard models as far as the bed expansion is concerned. In addition, all simulations tended to under-predict the bubble size substantially. Effects of various model settings including both numerical and physical parameters have been investigated with no significant improvement observed. The latest filtered sub-grid drag model was then tested in the numerical simulations. Compared to the standard drag model, the filtered drag model with two markers not only predicted reasonable bed expansion but also yielded realistic bubbling behavior. As a result, a grid sensitivity study was conducted for the filtered sub-grid model and its applicability and limitation were discussed.

  10. Common Cold

    MedlinePlus

    ... nose, coughing - everyone knows the symptoms of the common cold. It is probably the most common illness. In ... avoid colds. There is no cure for the common cold. For relief, try Getting plenty of rest Drinking ...

  11. Cold Urticaria

    MedlinePlus

    ... throat when consuming cold food or drink Severe reactions may include: A whole-body response (anaphylaxis), which ... to cold water. The majority of cold urticaria reactions occur when skin is exposed to temperatures lower ...

  12. Cold temperature improves mobility and survival in Drosophila models of autosomal-dominant hereditary spastic paraplegia (AD-HSP).

    PubMed

    Baxter, Sally L; Allard, Denise E; Crowl, Christopher; Sherwood, Nina Tang

    2014-08-01

    Autosomal-dominant hereditary spastic paraplegia (AD-HSP) is a crippling neurodegenerative disease for which effective treatment or cure remains unknown. Victims experience progressive mobility loss due to degeneration of the longest axons in the spinal cord. Over half of AD-HSP cases arise from loss-of-function mutations in spastin, which encodes a microtubule-severing AAA ATPase. In Drosophila models of AD-HSP, larvae lacking Spastin exhibit abnormal motor neuron morphology and function, and most die as pupae. Adult survivors display impaired mobility, reminiscent of the human disease. Here, we show that rearing pupae or adults at reduced temperature (18°C), compared with the standard temperature of 24°C, improves the survival and mobility of adult spastin mutants but leaves wild-type flies unaffected. Flies expressing human spastin with pathogenic mutations are similarly rescued. Additionally, larval cooling partially rescues the larval synaptic phenotype. Cooling thus alleviates known spastin phenotypes for each developmental stage at which it is administered and, notably, is effective even in mature adults. We find further that cold treatment rescues larval synaptic defects in flies with mutations in Flower (a protein with no known relation to Spastin) and mobility defects in flies lacking Kat60-L1, another microtubule-severing protein enriched in the CNS. Together, these data support the hypothesis that the beneficial effects of cold extend beyond specific alleviation of Spastin dysfunction, to at least a subset of cellular and behavioral neuronal defects. Mild hypothermia, a common neuroprotective technique in clinical treatment of acute anoxia, might thus hold additional promise as a therapeutic approach for AD-HSP and, potentially, for other neurodegenerative diseases. © 2014. Published by The Company of Biologists Ltd.

  13. [In vitro study of the flow duration of antibiotics solutions prepared in elastomeric infusion devices: effect of cold storage for 3 to 7days].

    PubMed

    Grangeon-Chapon, C; Robein-Dobremez, M-J; Pin, I; Trouiller, P; Allenet, B; Foroni, L

    2015-09-01

    Within the cystic fibrosis patients' home care, EMERAA network ("Together against Cystic fibrosis in Rhone-Alpes and Auvergne") organizes parenteral antibiotics cures at home prepared in elastomeric infusion devices by hospital pharmacies. However, patients and nurses found that the durations of infusion with these devices were often longer than the nominal duration of infusion indicated by their manufacturer. This study aimed to identify the potential different causes in relation to these discordances. Three hundred and ninety devices of two different manufacturers are tested in different experimental conditions: three antibiotics each at two different doses, duration of cold storage (three days or seven days) or immediate tests without cold storage, preparation and storage of the solution in the device (protocol Device) or transfer in the device just before measurement (protocol Pocket). All tests highlighted a longer flow duration for devices prepared according to the protocol Device versus the protocol Pocket (P=0.004). Flow duration is increased in the case of high doses of antibiotics with high viscosity such as piperacilline/tazobactam. The results of this in vitro study showed the impact of: (1) the time between the filling of the device and the flow of the solution; (2) cold storage of elastomeric infusion devices; (3) concentration of antibiotics and therefore the viscosity of the solution to infuse. It is therefore essential that health care teams are aware of factors, which may lead to longer infusion durations with these infusion devices. When the additional time for infusion remain acceptable, it should be necessary to inform the patient and to relativize these lengthening compared to many benefits that these devices provide for home care. Copyright © 2015 Elsevier Masson SAS. All rights reserved.

  14. On improving cold region hydrological processes in the Canadian Land Surface Scheme

    NASA Astrophysics Data System (ADS)

    Ganji, Arman; Sushama, Laxmi; Verseghy, Diana; Harvey, Richard

    2017-01-01

    Regional and global climate model simulated streamflows for high-latitude regions show systematic biases, particularly in the timing and magnitude of spring peak flows. Though these biases could be related to the snow water equivalent and spring temperature biases in models, a good part of these biases is due to the unaccounted effects of non-uniform infiltration capacity of the frozen ground and other related processes. In this paper, the treatment of frozen water in the Canadian Land Surface Scheme (CLASS), which is used in the Canadian regional and global climate models, is modified to include fractional permeable area, supercooled liquid water and a new formulation for hydraulic conductivity. The impact of these modifications on the regional hydrology, particularly streamflow, is assessed by comparing three simulations performed with the original and two modified versions of CLASS, driven by atmospheric forcing data from the European Centre for Medium-Range Weather Forecast (ECMWF) reanalysis (ERA-Interim) for the 1990-2001 period over a northeast Canadian domain. The two modified versions of CLASS differ in the soil hydraulic conductivity and matric potential formulations, with one version being based on formulations from a previous study and the other one is newly proposed. Results suggest statistically significant decreases in infiltration and therefore soil moisture during the snowmelt season for the simulation with the new hydraulic conductivity and matric potential formulations and fractional permeable area concept compared to the original version of CLASS, which is also reflected in the increased spring surface runoff and streamflows in this simulation with modified CLASS over most of the study domain. The simulated spring peaks and their timing in this simulation are also in better agreement to those observed. This study thus demonstrates the importance of treatment of frozen water for realistic simulation of streamflows.

  15. Evidence for viscous flow nature in Zr{sub 60}Al{sub 15}Ni{sub 25} metallic glass subjected to cold rolling

    SciTech Connect

    Yan Zhijie; Hao Weixin; Hu Yong; Song Kaikai; Eckert, Juergen; Stoica, Mihai; Scudino, Sergio

    2013-07-08

    The microstructure changes of Zr{sub 60}Al{sub 15}Ni{sub 25} metallic glass upon cold rolling and their influences on the thermally induced crystallization kinetics are investigated. The results show that atomic redistribution occurs within the localized zones in the glassy matrix, resulting from the softening of the shear modulus, which retards the crystallization behaviors during the subsequent heating. The present work provides direct evidence for the viscous flow nature in a metallic glass subjected to plastic deformation, during which the softened zones act as potential shear transformation zones.

  16. Cold Oxygen Plasma Treatments for the Improvement of the Physicochemical and Biodegradable Properties of Polylactic Acid Films for Food Packaging.

    PubMed

    Song, Ah Young; Oh, Yoon Ah; Roh, Si Hyeon; Kim, Ji Hyeon; Min, Sea C

    2016-01-01

    The effects of cold plasma (CP) treatment on the physicochemical and biodegradable properties of polylactic acid (PLA) films were studied. The PLA films were exposed to CP for 40 min at 900 W and 667 Pa using oxygen as the plasma-forming gas. The tensile, optical, and dynamic mechanical thermal properties, surface morphology, printability, water contact angle, chemical structure, weight change, and biodegradability properties of the films were evaluated during storage for up to 56 d. The tensile and optical properties of the PLA films were not significantly affected by CP treatment (CPT; P > 0.05). The surface roughness and water contact angle of PLA films increased by CPT and further increased during storage for 56 d. The printability of the PLA films increased following CPT and remained stable throughout the storage period. CP-induced hydrophilicity was also sustained during the storage period. The PLA films lost 1.9% of their weight after CPT, but recovered 99.5% of this loss after 14 d in storage. Photodegradation, thermal, and microbial biodegradable properties of the films were significantly improved by CPT (P < 0.05). Accelerated biodegradation of CP-treated PLA sachets with and without cheese was observed in compost. These results demonstrate the potential of CPT for modifying the stiffness, water contact angle, and chemical structure of PLA films and improving the printability and biodegradability of the films for food packaging.

  17. Some like it hot, some like it cold: Temperature dependent biotechnological applications and improvements in extremophilic enzymes.

    PubMed

    Siddiqui, Khawar Sohail

    2015-12-01

    The full biotechnological exploitation of enzymes is still hampered by their low activity, low stability and high cost. Temperature-dependent catalytic properties of enzymes are a key to efficient and cost-effective translation to commercial applications. Organisms adapted to temperature extremes are a rich source of enzymes with broad ranging thermal properties which, if isolated, characterized and their structure-function-stability relationship elucidated, could underpin a variety of technologies. Enzymes from thermally-adapted organisms such as psychrophiles (low-temperature) and thermophiles (high-temperature) are a vast natural resource that is already under scrutiny for their biotechnological potential. However, psychrophilic and thermophilic enzymes show an activity-stability trade-off that necessitates the use of various genetic and chemical modifications to further improve their properties to suit various industrial applications. This review describes in detail the properties and biotechnological applications of both cold-adapted and thermophilic enzymes. Furthermore, the review critically examines ways to improve their value for biotechnology, concluding by proposing an integrated approach involving thermally-adapted, genetically and magnetically modified enzymes to make biocatalysis more efficient and cost-effective.

  18. Coupled expression of Cu/Zn-superoxide dismutase and catalase in cassava improves tolerance against cold and drought stresses.

    PubMed

    Xu, Jia; Duan, Xiaoguang; Yang, Jun; Beeching, John R; Zhang, Peng

    2013-06-01

    Recently we reported that the joint expression of cassava Cu/Zn superoxide dismutase (MeCu/ZnSOD) and catalase (MeCAT1) prolonged the shelf life of cassava storage-roots by the stabilization of reactive oxygen species (ROS) homeostasis after harvest. Since oxidative damage is a major feature of plants exposed to environmental stresses, transgenic cassava showing increased expression of the cytosolic MeCu/ZnSOD and the peroxisomal MeCAT1 should have improved resistance against other abiotic stresses. After cold treatment, the transgenic cassava maintained higher SOD and CAT activities and lower malendialdehyde content than those of wild type plants (WT). Detached leaves of transgenic cassava also showed slower transpirational water loss than those of WT. When plants were not watered for 30 d, transgenic lines exhibited a significant increase in water retention ability, accumulated 13% more proline and 12% less malendialdehyde than WT's, and showed enhanced activity of SOD and CAT. These results imply that manipulation of the antioxidative mechanism allows the development of staple crops with improved tolerance to abiotic stresses.

  19. Improving patient flow in pre-operative assessment

    PubMed Central

    Stark, Cameron; Gent, Anne; Kirkland, Linda

    2015-01-01

    Annual patient attendances at a pre-operative assessment department increased by 24.8% from 5659 in 2009, to 7062 in 2012. The unit was staffed by administrative staff, nurses, and health care assistants (HCA). Medical review was accessed via on call medical staff, or notes were sent to anaesthetists for further review. With rising demand, patient waits increased. The average lead time for a patient (time from entering the department to leaving) was 79 minutes. 9.3% of patients attended within two weeks of their scheduled surgery date. 10% of patients were asked to return on a later day, as there was not sufficient capacity to undertake their assessment. There were nine routes of referral in to the department. Patients moved between different clinic rooms and the waiting area several times. Work patterns were uneven, as many attendances were from out-patient clinics which meant peak attendance times were linked to clinic times. There were substantial differences in the approaches of different nurses, making the HCA role difficult. Patients reported dissatisfaction with waits. Using a Lean quality improvement process with rapid PDSA cycles, the service changed to one in which patients were placed in a room, and remained there for the duration of their assessment. Standard work was developed for HCWs and nurses. Rooms were standardised using 5S processes, and set up improved to reduce time spent looking for supplies. A co-ordinator role was introduced using existing staff to monitor flow and to organise the required medical assessments and ECGs. Timing of booked appointments were altered to take account of clinic times. Routes in to the department were reduced from nine to one. Ten months after the work began, the average lead time had reduced to 59 minutes. The proportion of people attending within two weeks of their surgery decreased from 9.3% to 5.3%. Referrals for an anaesthetic opinion decreased from 30% to 20%, and in the month reviewed no one had to return to

  20. A deficiency in cold-inducible RNA-binding protein accelerates the inflammation phase and improves wound healing.

    PubMed

    Idrovo, Juan Pablo; Jacob, Asha; Yang, Weng Lang; Wang, Zhimin; Yen, Hao Ting; Nicastro, Jeffrey; Coppa, Gene F; Wang, Ping

    2016-02-01

    Chronic or non-healing wounds are a major concern in clinical practice and these wounds are mostly associated with diabetes, and venous and pressure ulcers. Wound healing is a complex process involving overlapping phases and the primary phase in this complex cascade is the inflammatory state. While inflammation is necessary for wound healing, a prolonged inflammatory phase leads to impaired healing. Cold-inducible RNA-binding protein (CIRP) belongs to a family of cold-shock proteins that are expressed in high levels under stress conditions. Recently, we demonstrated that a deficiency in CIRP led to decreased inflammation and mortality in an experimental model of hemorrhagic shock. Thus, we hypothesized that a deficiency in CIRP would accelerate the inflammatory phase and lead to an improvement in cutaneous wound healing. In this study, to examine this hypothesis, a full-thickness wound was created on the dorsum of wild-type (WT) and CIRP-/- mice. The wound size was measured every other day for 14 days. The wound area was significantly decreased in the CIRP-/- mice by day 9 and continued to decrease until day 14 compared to the WT mice. In a separate cohort, mice were sacrificed on days 3 and 7 after wounding and the skin tissues were harvested for histological analysis and RNA measurements. On day 3, the mRNA expression of tumor necrossis factor (TNF)-α in the skin tissues was increased by 16-fold in the WT mice, whereas these levels were increased by 65-fold in the CIRP-/- mice. Of note on day 7, while the levels of TNF-α remained high in the WT mice, these levels were significantly decreased in the CIRP-/- mice. The histological analysis of the wounded skin tissue indicated an improvement as early as day 3 in the CIRP-/- mice, whereas in the WT mice, infiltrated immune cells were still present on day 7. On day 7 in the CIRP-/- mice, Gr-1 expression was low and CD31 expression was high, whereas in the WT mice, Gr-1 expression was high and CD31 expression was low

  1. Improving the environment for weaned piglets using polypropylene fabrics above the animals in cold periods.

    PubMed

    Dolz, Noé; Babot, Daniel; Álvarez-Rodríguez, Javier; Forcada, Fernando

    2015-12-01

    This study aimed at evaluating the use of polypropylene fabrics in weaned pig facilities (5-10 weeks of age) during the winter period to improve thermal environment and energy saving for heating. Two experiments were conducted to validate the effects of fabrics (F) compared to control (C) in three 2-week periods using natural ventilation (assay 1, 2013) and forced ventilation (assay 2, 2014). Air temperature was greater in F than in C compartments in both years, particularly during the first 2-week periods (2 °C of mean difference). Natural ventilation was not enough to maintain relative humidity levels below 70 % at the end of the postweaning period (9-10 weeks of age) in both groups (F and C), whereas forced ventilation allowed controlling daily mean relative humidity levels <60 %. About 12-26 % of the radiant heat was transmitted through the fabrics cover, depending on the wavelength. There were no differences on growth performance of piglets in the two compartments in both years. The use of polypropylene fabrics was associated with a significant electric energy saving for heating during the first (data available only in 2014) and second 2-week period in both years. In conclusion, polypropylene fabrics may be an interesting tool to provide optimal environmental conditions for weaned piglets in winter, especially during the two first weeks after weaning. Their transmittance properties allow trapping infrared emission produced by the piglets and heating, avoiding heat losses through the roof, and therefore saving heating energy.

  2. Improving the environment for weaned piglets using polypropylene fabrics above the animals in cold periods

    NASA Astrophysics Data System (ADS)

    Dolz, Noé; Babot, Daniel; Álvarez-Rodríguez, Javier; Forcada, Fernando

    2015-12-01

    This study aimed at evaluating the use of polypropylene fabrics in weaned pig facilities (5-10 weeks of age) during the winter period to improve thermal environment and energy saving for heating. Two experiments were conducted to validate the effects of fabrics (F) compared to control (C) in three 2-week periods using natural ventilation (assay 1, 2013) and forced ventilation (assay 2, 2014). Air temperature was greater in F than in C compartments in both years, particularly during the first 2-week periods (2 °C of mean difference). Natural ventilation was not enough to maintain relative humidity levels below 70 % at the end of the postweaning period (9-10 weeks of age) in both groups (F and C), whereas forced ventilation allowed controlling daily mean relative humidity levels <60 %. About 12-26 % of the radiant heat was transmitted through the fabrics cover, depending on the wavelength. There were no differences on growth performance of piglets in the two compartments in both years. The use of polypropylene fabrics was associated with a significant electric energy saving for heating during the first (data available only in 2014) and second 2-week period in both years. In conclusion, polypropylene fabrics may be an interesting tool to provide optimal environmental conditions for weaned piglets in winter, especially during the two first weeks after weaning. Their transmittance properties allow trapping infrared emission produced by the piglets and heating, avoiding heat losses through the roof, and therefore saving heating energy.

  3. Gas flow means for improving efficiency of exhaust hoods

    DOEpatents

    Gadgil, Ashok J.

    1994-01-01

    Apparatus for inhibiting the flow of contaminants in an exhaust enclosure toward an individual located adjacent an opening into the exhaust enclosure by providing a gas flow toward a source of contaminants from a position in front of an individual to urge said contaminants away from the individual toward a gas exit port. The apparatus comprises a gas mani-fold which may be worn by a person as a vest. The manifold has a series of gas outlets on a front face thereof facing away from the individual and toward the contaminants to thereby provide a flow of gas from the front of the individual toward the contaminants.

  4. Gas flow means for improving efficiency of exhaust hoods

    DOEpatents

    Gadgil, A.J.

    1994-01-11

    Apparatus is described for inhibiting the flow of contaminants in an exhaust enclosure toward an individual located adjacent an opening into the exhaust enclosure by providing a gas flow toward a source of contaminants from a position in front of an individual to urge said contaminants away from the individual toward a gas exit port. The apparatus comprises a gas manifold which may be worn by a person as a vest. The manifold has a series of gas outlets on a front face thereof facing away from the individual and toward the contaminants to thereby provide a flow of gas from the front of the individual toward the contaminants. 15 figures.

  5. Improved drought tolerance in wheat plants overexpressing a synthetic bacterial cold shock protein gene SeCspA

    PubMed Central

    Yu, Tai-Fei; Xu, Zhao-Shi; Guo, Jin-Kao; Wang, Yan-Xia; Abernathy, Brian; Fu, Jin-Dong; Chen, Xiao; Zhou, Yong-Bin; Chen, Ming; Ye, Xing-Guo; Ma, You-Zhi

    2017-01-01

    Cold shock proteins (CSPs) enhance acclimatization of bacteria to adverse environmental circumstances. The Escherichia coli CSP genes CspA and CspB were modified to plant-preferred codon sequences and named as SeCspA and SeCspB. Overexpression of exogenous SeCspA and SeCspB in transgenic Arabidopsis lines increased germination rates, survival rates, and increased primary root length compared to control plants under drought and salt stress. Investigation of several stress-related parameters in SeCspA and SeCspB transgenic wheat lines indicated that these lines possessed stress tolerance characteristics, including lower malondialdehyde (MDA) content, lower water loss rates, lower relative Na+ content, and higher chlorophyll content and proline content than the control wheat plants under drought and salt stresses. RNA-seq and qRT-PCR expression analysis showed that overexpression of SeCsp could enhance the expression of stress-responsive genes. The field experiments showed that the SeCspA transgenic wheat lines had great increases in the 1000-grain weight and grain yield compared to the control genotype under drought stress conditions. Significant differences in the stress indices revealed that the SeCspA transgenic wheat lines possessed significant and stable improvements in drought tolerance over the control plants. No such improvement was observed for the SeCspB transgenic lines under field conditions. Our results indicated that SeCspA conferred drought tolerance and improved physiological traits in wheat plants. PMID:28281578

  6. Improved technique for blood flow velocity measurement using Doppler effect

    NASA Astrophysics Data System (ADS)

    Valadares Oliveira, Eduardo J.; Nantes Button, Vera L. d. S.; Maia, Joaquim M.; Costa, Eduardo T.

    2002-04-01

    The Doppler velocimeter developed allows to determine the angle between the ultrasonic beam and the velocity vector of the flow, and to calculate the precise blood flow in a vessel. Four piezoelectric transducers constitute the Doppler velocimeter. Three of these transducers are positioned to form an equilateral triangle (base of a pyramid). When these transducers move simultaneously, backward or forward from the initial position, the emitted ultrasonic beams focalize on a position (peak of the pyramid) closer or farther from the transducers faces, according to the depth of the vessel where we intend to measure de flow. The angle between the transducers allows adjusting the height of this pyramid and the position of the focus (where the three beams meet). A forth transducer is used to determine the diameter of the vessel and monitor the position of the Doppler velocimeter relative to the vessel. Simulation results showed that with this technique is possible to accomplish precise measurement of blood flow.

  7. Improved Flux Formulations for Unsteady Low Mach Number Flows

    DTIC Science & Technology

    2012-07-01

    Many practical applications including rotorcraft flows, jets and shear layers include a combination of both acoustic and hydrodynamic effects...characteristics may vary (e.g. high frequency in the near field of a turbulent jet and low frequency in the far-field) the ability for the numerical formulation...the CRUNCH CFD ® code, developed at CRAFT Tech [12]-[15]. The candidate flux formulations for unsteady low Mach number flows will be tested out

  8. Enhanced Cholinergic Activity Improves Cerebral Blood Flow during Orthostatic Stress

    PubMed Central

    Serrador, Jorge M.; Freeman, Roy

    2017-01-01

    Cerebral blood flow (CBF) and consequently orthostatic tolerance when upright depends on dilation of the cerebral vasculature in the face of reduced perfusion pressure associated with the hydrostatic gradient. However, it is still unclear if cholinergic activation plays a role in this dilation. To determine if enhancing central cholinergic activity with the centrally acting acetylcholinesterase inhibitor, physostigmine would increase CBF when upright compared to the peripherally acting acetylcholinesterase inhibitor, neostigmine, or saline. We performed a randomized double-blind dose-ranging study that took place over 3 days in a hospital-based research lab. Eight healthy controls (six women and two men, mean age, 26 years; range 21–33) were given infusions of physostigmine, neostigmine, or saline on three different days. Five-minute tilts were repeated at baseline (no infusion), Dose 1 (0.2 μg/kg/min physostigmine; 0.1 μg/kg/min neostigmine) and Dose 2 (0.6 μg/kg/min physostigmine or 0.3 μg/kg/min neostigmine), and placebo (0.9% NaCl). Cerebral blood velocity, beat-to-beat blood pressure, and end-tidal CO2 were continuously measured during tilts. Physostigmine (0.6 μg/kg/min) resulted in higher cerebral blood velocity during tilt (90.5 ± 1.5%) than the equivalent neostigmine (85.5 ± 2.6%) or saline (84.8 ± 1.7%) trials (P < 0.05). This increase occurred despite a greater postural hypocapnia, suggesting physostigmine had a direct vasodilatory effect on the cerebral vasculature. Cerebral hypoperfusion induced by repeated tilts was eliminated by infusion of physostigmine not neostigmine. In conclusion, this study provides the first evidence that enhancement of central, not peripheral, cholinergic activity attenuates the physiological decrease in CBF seen during upright tilt. These data support the need for further research to determine if enhancing central cholinergic activity may improve symptoms in patients with symptomatic

  9. Cold flow scaleup facility experimental results and comparison of performance at different bed configurations, Volume 1: Topical report, January--December 1983

    SciTech Connect

    Schmidt, D.K.; Yang, W.C.; Ettehadieh, B.; Anestis, T.C.; Haldipur, G.B.; Kettering, E.; O'Rourke, R.E.; Weigle, D.

    1988-12-01

    KRW Energy Systems Inc. is engaged in the continuing development of a pressurized, fluidized-bed gasification process at its Waltz Mill Site in Madison, Pennsylvania. The overall objective of the program is to demonstrate the viability of the KRW process for the environmentally acceptable production of low- and medium-BTU fuel gas from a variety of fossilized carbonaceous feedstocks for electric power generation, synthetic natural gas, chemical feedstocks and industrial fuels. This report presents analysis of the Cold Flow Scaleup Facility (CFSF) operations. Included is work performed on the 3-meter CFSF model using four different bed configurations to check correlations and scale-up criteria developed from studies conducted in small-scale cold flow units and those available in open literature. The 3-meter model permits full front-face viewing of the fluidized bed through a transparent plastic window and with its instrumentation allows detailed studies of jet behavior, bubble dynamics, solid circulation, gas mixing, and related phenomena important to the design of a large-scale gasifier. 87 refs., 95 figs., 56 tabs.

  10. Improving the dielectric and piezoelectric properties of screen-printed Low temperature PZT/polymer composite using cold isostatic pressing

    NASA Astrophysics Data System (ADS)

    Almusallam, A.; Yang, K.; Cao, Z.; Zhu, D.; Tudor, J.; Beeby, S. P.

    2014-11-01

    This paper reports an improvement in dielectric and piezoelectric properties of screen-printed PZT/polymer films for flexible electronics applications using Cold Isostatic Pressing (CIP). The investigation involved half and fully cured PZT/polymer composite pastes with weight ratio of 12:1 to investigate the effect of the CIP process on the piezoelectric and dielectric properties. It was observed that the highest dielectric and piezoelectric properties are achieved at pressures of 5 and 10 MPa for half and fully cured films respectively. The relative dielectric constants were 300 and 245 measured at 1 kHz for the half and fully cured samples. Using unoptimised poling conditions, the initial d33 values were 30 and 35 pC/N for the half and fully cured films, respectively. The fully cured sample was then poled using optimized conditions and demonstrated a d33 of approximately 44 pC/N which is an increase of 7% compared with non-CIP processed materials.

  11. PIV Validation of 3D Multicomponent Model for Cold Spray Within Nitrogen and Helium Supersonic Flow Field

    NASA Astrophysics Data System (ADS)

    Faizan-Ur-Rab, M.; Zahiri, S. H.; Masood, S. H.; Jahedi, M.; Nagarajah, R.

    2017-06-01

    This study presents the validation of a developed three-dimensional multicomponent model for cold spray process using two particle image velocimetry (PIV) experiments. The k- ɛ type 3D model developed for spherical titanium particles was validated with the measured titanium particle velocity within a nitrogen and helium supersonic jet. The 3D model predicted lower values of particle velocity than the PIV experimental study that used irregularly shaped titanium particles. The results of the 3D model were consistent with the PIV experiment that used spherical titanium powder. The 3D model simulation of particle velocity within the helium and nitrogen jet was coupled with an estimation of titanium particle temperature. This was achieved with the consideration of the fact that cold spray particle temperature is difficult and expensive to measure due to considerably lower temperature of particles than thermal spray. The model predicted an interesting pattern of particle size distribution with respect to the location of impact with a concentration of finer particles close to the jet center. It is believed that the 3D model outcomes for particle velocity, temperature and location could be a useful tool to optimize system design, deposition process and mechanical properties of the additively manufactured cold spray structures.

  12. Characterization of water quality and suspended sediment during cold-season flows, warm-season flows, and stormflows in the Fountain and Monument Creek watersheds, Colorado, 2007–2015

    USGS Publications Warehouse

    Miller, Lisa D.; Stogner, Sr., Robert W.

    2017-09-01

    From 2007 through 2015, the U.S. Geological Survey, in cooperation with Colorado Springs City Engineering, conducted a study in the Fountain and Monument Creek watersheds, Colorado, to characterize surface-water quality and suspended-sediment conditions for three different streamflow regimes with an emphasis on characterizing water quality during storm runoff. Data collected during this study were used to evaluate the effects of stormflows and wastewater-treatment effluent discharge on Fountain and Monument Creeks in the Colorado Springs, Colorado, area. Water-quality samples were collected at 2 sites on Upper Fountain Creek, 2 sites on Monument Creek, 3 sites on Lower Fountain Creek, and 13 tributary sites during 3 flow regimes: cold-season flow (November–April), warm-season flow (May–October), and stormflow from 2007 through 2015. During 2015, additional samples were collected and analyzed for Escherichia coli (E. coli) during dry weather conditions at 41 sites, located in E. coli impaired stream reaches, to help identify source areas and scope of the impairment.Concentrations of E. coli, total arsenic, and dissolved copper, selenium, and zinc in surface-water samples were compared to Colorado in-stream standards. Stormflow concentrations of E. coli frequently exceeded the recreational use standard of 126 colonies per 100 milliliters at main-stem and tributary sites by more than an order of magnitude. Even though median E. coli concentrations in warm-season flow samples were lower than median concentrations in storm-flow samples, the water quality standard for E. coli was still exceeded at most main-stem sites and many tributary sites during warm-season flows. Six samples (three warm-season flow and three stormflow samples) collected from Upper Fountain Creek, upstream from the confluence of Monument Creek, and two stormflow samples collected from Lower Fountain Creek, downstream from the confluence with Monument Creek, exceeded the acute water

  13. Cold habituation does not improve manual dexterity during rest and exercise in 5 °C.

    PubMed

    Muller, Matthew D; Seo, Yongsuk; Kim, Chul-Ho; Ryan, Edward J; Pollock, Brandon S; Burns, Keith J; Glickman, Ellen L

    2014-04-01

    When exposed to a cold environment, a barehanded person experiences pain, cold sensation, and reduced manual dexterity. Both acute (e.g. exercise) and chronic (e.g. cold acclimatization or habituation) processes might lessen these negative effects. The purpose of this experiment was to determine the effect of cold habituation on physiology, perception, and manual dexterity during rest, exercise, and recovery in 5 °C. Six cold weather athletes (CWA) and eight non habituated men (NON) volunteered to participate in a repeated measures cross-over design. The protocol was conducted in 5 °C and was 90 min of resting cold exposure, 30 min of cycle ergometry exercise (50 % VO2 peak), and 60 min of seated recovery. Core and finger skin temperature, metabolic rate, Purdue Pegboard dexterity performance, hand pain, thermal sensation, and mood were quantified. Exercise-induced finger rewarming (EIFRW) was calculated for each hand. During 90 min of resting exposure to 5 °C, the CWA had a smaller reduction in finger temperature, a lower metabolic rate, less hand pain, and less negative mood. Despite this cold habituation, dexterity performance was not different between groups. In response to cycle ergometry, EIFRW was greater in CWA (~12 versus 7 °C) and occurred at lower core temperatures (37.02 versus 37.31 °C) relative to NON but dexterity was not greater during post-exercise recovery. The current data indicate that cold habituated men (i.e., CWA) do not perform better on the Purdue Pegboard during acute cold exposure. Furthermore, despite augmented EIFRW in CWA, dexterity during post-exercise recovery was similar between groups.

  14. Best practices for improving flow and care of pediatric patients in the emergency department.

    PubMed

    Barata, Isabel; Brown, Kathleen M; Fitzmaurice, Laura; Griffin, Elizabeth Stone; Snow, Sally K

    2015-01-01

    This report provides a summary of best practices for improving flow, reducing waiting times, and improving the quality of care of pediatric patients in the emergency department. Copyright © 2015 by the American Academy of Pediatrics.

  15. A consortium of rhizobacterial strains and biochemical growth elicitors improve cold and drought stress tolerance in rice (Oryza sativa L.).

    PubMed

    Kakar, K U; Ren, X-L; Nawaz, Z; Cui, Z-Q; Li, B; Xie, G-L; Hassan, M A; Ali, E; Sun, G-C

    2016-05-01

    In the present study, a consortium of two rhizobacteria Bacillus amyloliquefaciens Bk7 and Brevibacillus laterosporus B4, termed 'BB', biochemical elicitors salicylic acid and β-aminobutyric acid (SB) and their mixture (BBSB) were investigated for cold and drought stress tolerance in rice plants. After withholding water for 16 days, rice plants treated with BBSB showed 100% survival, improved seedling height (35.4 cm), shoot number (6.12), and showed minimum symptoms of chlorosis (19%), wilting (4%), necrosis (6%) and rolling of leaves. Similarly, BB inoculation enhanced plant growth and reduced overall symptoms in rice seedlings subjected to 0 ± 5 °C for 24 h. Our results imply several mechanisms underlying BB- and BBSB-elicited stress tolerance. In contrast to the control, both treatments significantly decreased leaf monodehydroascorbate (MDA) content and electrolyte leakage, and increased leaf proline and cholorophyll content. Moreover, activities of antioxidant enzymes, superoxide dismutase (SOD) and catalase (CAT) increased 3.0- and 3.6-fold, respectively. Moreover, expression of OsMYB3R-2, OsDIL, OsDREB1A and OsCDPK13 genes was significantly up-regulated, suggesting that these genes play important roles in abiotic stress tolerance of rice. In addition, bacterial strains Bk7 and B4 were able to produce high amounts of IAA and siderophores, and colonise the plant roots, while only strain Bk7 exhibited the capability to form biofilms and solubilise inorganic phosphate. This study indicates that the BB and BBSB bio-formulations can be used to confer induced systematic tolerance and improve the health of rice plants subject to chilling and drought stress. © 2016 German Botanical Society and The Royal Botanical Society of the Netherlands.

  16. Improvement of COBRA-TF for modeling of PWR cold- and hot-legs during reactor transients

    NASA Astrophysics Data System (ADS)

    Salko, Robert K.

    COBRA-TF is a two-phase, three-field (liquid, vapor, droplets) thermal-hydraulic modeling tool that has been developed by the Pacific Northwest Laboratory under sponsorship of the NRC. The code was developed for Light Water Reactor analysis starting in the 1980s; however, its development has continued to this current time. COBRA-TF still finds wide-spread use throughout the nuclear engineering field, including nuclear-power vendors, academia, and research institutions. It has been proposed that extension of the COBRA-TF code-modeling region from vessel-only components to Pressurized Water Reactor (PWR) coolant-line regions can lead to improved Loss-of-Coolant Accident (LOCA) analysis. Improved modeling is anticipated due to COBRA-TF's capability to independently model the entrained-droplet flow-field behavior, which has been observed to impact delivery to the core region[1]. Because COBRA-TF was originally developed for vertically-dominated, in-vessel, sub-channel flow, extension of the COBRA-TF modeling region to the horizontal-pipe geometries of the coolant-lines required several code modifications, including: • Inclusion of the stratified flow regime into the COBRA-TF flow regime map, along with associated interfacial drag, wall drag and interfacial heat transfer correlations, • Inclusion of a horizontal-stratification force between adjacent mesh cells having unequal levels of stratified flow, and • Generation of a new code-input interface for the modeling of coolant-lines. The sheer number of COBRA-TF modifications that were required to complete this work turned this project into a code-development project as much as it was a study of thermal-hydraulics in reactor coolant-lines. The means for achieving these tasks shifted along the way, ultimately leading the development of a separate, nearly completely independent one-dimensional, two-phase-flow modeling code geared toward reactor coolant-line analysis. This developed code has been named CLAP, for

  17. Speed from light: growth rate and bulk flow at z ˜ 0.1 from improved SDSS DR13 photometry

    NASA Astrophysics Data System (ADS)

    Feix, M.; Branchini, E.; Nusser, A.

    2017-06-01

    Observed galaxy luminosities (derived from redshifts) hold information on the large-scale peculiar velocity field in the form of spatially correlated scatter, which allows for bounds on bulk flows and the growth rate of matter density perturbations using large galaxy redshift surveys. We apply this luminosity approach to galaxies from the recent SDSS Data Release 13. Our goal is twofold. First, we take advantage of the recalibrated photometry to identify possible systematic errors relevant to our previous analysis of earlier data. Second, we seek improved constraints on the bulk flow and the normalized growth rate fσ8 at z ˜ 0.1. Our results confirm the robustness of our method. Bulk flow amplitudes, estimated in two redshift bins with 0.02 < z1 < 0.07 < z2 < 0.22, are generally smaller than in previous measurements, consistent with both the updated photometry and expectations for the Λ cold dark matter model. The obtained growth rate, fσ8 = 0.48 ± 0.16, is larger than, but still compatible with, its previous estimate, and closer to the reference value of Planck. Rather than precision, the importance of these results is due to the fact that they follow from an independent method that relies on accurate photometry, which is a top requirement for next-generation photometric catalogues.

  18. Elements of an improved model of debris‐flow motion

    USGS Publications Warehouse

    Iverson, Richard M.

    2009-01-01

    A new depth‐averaged model of debris‐flow motion describes simultaneous evolution of flow velocity and depth, solid and fluid volume fractions, and pore‐fluid pressure. Non‐hydrostatic pore‐fluid pressure is produced by dilatancy, a state‐dependent property that links the depth‐averaged shear rate and volumetric strain rate of the granular phase. Pore‐pressure changes caused by shearing allow the model to exhibit rate‐dependent flow resistance, despite the fact that the basal shear traction involves only rate‐independent Coulomb friction. An analytical solution of simplified model equations shows that the onset of downslope motion can be accelerated or retarded by pore‐pressure change, contingent on whether dilatancy is positive or negative. A different analytical solution shows that such effects will likely be muted if downslope motion continues long enough, because dilatancy then evolves toward zero, and volume fractions and pore pressure concurrently evolve toward steady states.

  19. On improvement of air flow in wind tunnels

    NASA Technical Reports Server (NTRS)

    Wieselsberger, C

    1928-01-01

    The most important aerodynamical qualities that should be aimed at in wind tunnel design, are as follows: 1) constant and parallel direction of flow; 2) uniform velocity across all sections; 3) absence of turbulent motion; 4) constant velocity of flow. The above-mentioned qualities are all realized in a high degree in the Gottingen type of wind tunnel, with a parallel portion before the working section, the cross section of which is steadily reduced. It is shown in what follows, that the system can be applied to other wind tunnels, such as the N.P.L. or Eiffel type.

  20. U.S. stream flow measurement and data dissemination improve

    USGS Publications Warehouse

    Hirsch, Robert M.; Costa, John E.

    2004-01-01

    Stream flow information is essential for many important uses across a broad range of scales, including global water balances, engineering design, flood forecasting, reservoir operations, navigation, water supply, recreation, and environmental management. Growing populations and competing priorities for water, including preservation and restoration of aquatic habitat, are spurring demand for more accurate, timely, and accessible water data.To be most useful, stream flow information must be collected in a standardized manner, with a known accuracy, and for a long and continuous time period.

  1. Performance improvement of IPMC flow sensors with a biologically-inspired cupula structure

    NASA Astrophysics Data System (ADS)

    Lei, Hong; Sharif, Montassar Aidi; Paley, Derek A.; McHenry, Matthew J.; Tan, Xiaobo

    2016-04-01

    Ionic polymer-metal composites (IPMCs) have inherent underwater sensing and actuation properties. They can be used as sensors to collect flow information. Inspired by the hair-cell mediated receptor in the lateral line system of fish, the impact of a flexible, cupula-like structure on the performance of IPMC flow sensors is experimentally explored. The fabrication method to create a silicone-capped IPMC sensor is reported. Experiments are conducted to compare the sensing performance of the IPMC flow sensor before and after the PDMS coating under the periodic flow stimulus generated by a dipole source in still water and the laminar flow stimulus generated in a flow tank. Experimental results show that the performance of IPMC flow sensors is significantly improved under the stimulus of both periodic flow and laminar flow by the proposed silicone-capping.

  2. A pulse tube cryocooler with a cold reservoir

    NASA Astrophysics Data System (ADS)

    Zhang, X. B.; Zhang, K. H.; Qiu, L. M.; Gan, Z. H.; Shen, X.; Xiang, S. J.

    2013-02-01

    Phase difference between pressure wave and mass flow is decisive to the cooling capacity of regenerative cryocoolers. Unlike the direct phase shifting using a piston or displacer in conventional Stirling or GM cryocoolers, the pulse tube cyocooler (PTC) indirectly adjusts the cold phase due to the absence of moving parts at the cold end. The present paper proposed and validated theoretically and experimentally a novel configuration of PTC, termed cold reservoir PTC, in which a reservoir together with an adjustable orifice is connected to the cold end of the pulse tube. The impedance from the additional orifice to the cold end helps to increase the mass flow in phase with the pressure wave at the cold end. Theoretical analyses with the linear model for the orifice and double-inlet PTCs indicate that the cooling performance can be improved by introducing the cold reservoir. The preliminary experiments with a home-made single-stage GM PTC further validated the results on the premise of minor opening of the cold-end orifice.

  3. Improved Flow Modeling in Transient Reactor Safety Analysis Computer Codes

    SciTech Connect

    Holowach, M.J.; Hochreiter, L.E.; Cheung, F.B.

    2002-07-01

    A method of accounting for fluid-to-fluid shear in between calculational cells over a wide range of flow conditions envisioned in reactor safety studies has been developed such that it may be easily implemented into a computer code such as COBRA-TF for more detailed subchannel analysis. At a given nodal height in the calculational model, equivalent hydraulic diameters are determined for each specific calculational cell using either laminar or turbulent velocity profiles. The velocity profile may be determined from a separate CFD (Computational Fluid Dynamics) analysis, experimental data, or existing semi-empirical relationships. The equivalent hydraulic diameter is then applied to the wall drag force calculation so as to determine the appropriate equivalent fluid-to-fluid shear caused by the wall for each cell based on the input velocity profile. This means of assigning the shear to a specific cell is independent of the actual wetted perimeter and flow area for the calculational cell. The use of this equivalent hydraulic diameter for each cell within a calculational subchannel results in a representative velocity profile which can further increase the accuracy and detail of heat transfer and fluid flow modeling within the subchannel when utilizing a thermal hydraulics systems analysis computer code such as COBRA-TF. Utilizing COBRA-TF with the flow modeling enhancement results in increased accuracy for a coarse-mesh model without the significantly greater computational and time requirements of a full-scale 3D (three-dimensional) transient CFD calculation. (authors)

  4. Planning for ambulatory care: simple methods for improving patient flow.

    PubMed

    Schuh, S E; Tolins, I; Westphal, M C; Miller, M C

    1977-06-01

    A combined patient flow and work sampling study was done at the Ambulatory Pediatric Service of the Medical University of South Carolina. The biggest problem was that almost two thirds of the patient's time was spent waiting to see the doctor. Reasons for delay included too few examining rooms, the single block appointment system, and design of the facility.

  5. Toward the improved simulation of microscale gas flow

    NASA Astrophysics Data System (ADS)

    McNenly, Matthew James

    2007-12-01

    Recent interest in fluidic micro-electro-mechanical systems (MEMS) in gaseous environments has increased the need for accurate simulation techniques to aid in their design process. Many fluidic MEMS operate in a low-speed non-equilibrium gas flow regime that is challenging to simulate both accurately and efficiently. Classic computational fluid dynamics techniques (e.g. Navier-Stokes simulation) are based on the assumption that the fluid behaves as a continuum. This assumption, however, becomes increasingly less accurate as the local flow conditions deviate further from local thermodynamic equilibrium. Alternatively, it is possible to achieve an accurate approximation of non-equilibrium gas flows using particle-based methods (e.g. DSMC), but the resulting simulations are much more computationally expensive than the continuum-based method. In fact, for the very low speeds commonly found in fluidic MEMS, the slow convergence of the DSMC solution can lead to intractably long computation times on all but the largest supercomputers. Two different approaches are pursued in this investigation, in an effort to design a physically accurate and computationally efficient simulation of low-speed, non-equilibrium flows. The first approach constructs new empirical models to correct the error in the Navier-Stokes simulation in the transition regime due to the appreciable deviation from local thermodynamic equilibrium. The empirically corrected Navier-Stokes simulation is not actually predicting strongly non-equilibrium gas flows; however, it is shown to be a useful analysis tool in certain design situations. The second more novel approach develops an original quasi-Monte Carlo (QMC) particle simulation that retains the physical accuracy of the DSMC method while at the same time achieving a faster (near-linear) convergence rate. The design of a QMC method is far more complex in general than a Monte Carlo method for the same problem. Further, no known QMC particle simulation has

  6. Improved simulations of heat transfer in liquid metal flows.

    SciTech Connect

    Tzanos, C.

    2011-04-01

    In liquid-metal flows, the predictions of the Nusselt number (heat transfer) by Reynolds-averaged Navier-Stokes models of turbulence that use the assumption of a constant turbulent Prandtl number can be significantly off. Heat transfer analyses were performed with a number of turbulence models for flows in a triangular rod bundle and in a pipe, and model predictions were compared with experimental data. Emphasis was placed on the low Reynolds (low-Re) number k-{var_epsilon} model that resolves the boundary layer and does not use 'logarithmic wall functions.' The high Reynolds (high-Re) number k-{var_epsilon} model underpredicts the Nusselt number up to 30%, while the low-Re number model overpredicts it up to 34%. For high Peclet number values, the low-Re number model provides better predictions than the high-Re number model. For Peclet numbers higher than 1500, the predictions of the Reynolds stress model (RSM) are in very good agreement with experimental measurements, but for lower Peclet number values its predictions are significantly off. A relationship was developed that expresses the turbulent Prandtl number as a function of the ratio of the turbulent viscosity to the molecular viscosity. With this modified turbulent Prandtl number, for the flow in the rod bundle the predictions of the low-Re number model are well within the spread of the experimental measurements. For pipe flow, the model predictions are not as sensitive to the correction of the turbulent Prandtl number as they are in the case of the flow in a bundle. The modified low-Re number model underpredicts the limited experimental data by 4%.

  7. Does the Representation of Flow Structure and Turbulence at a Cold Front Converge on Multi-scale Observations with Model Resolution?

    NASA Astrophysics Data System (ADS)

    Harvey, Ben; Methven, John John; Eagle, Chloe; Lean, Humphrey

    2017-04-01

    In situ aircraft observations are used to interrogate the ability of a numerical weather prediction model to represent flow structure and turbulence at an intense cold front. Simulations are performed at a range of nested resolutions from grid spacings of 12 km down to 100 m and the convergence with resolution is investigated. The observations include the novel feature of a low-altitude circuit around the front that is closed in the frame of reference of the front, thus allowing the direct evaluation of area-average vorticity and divergence values from circuit integrals. As such, the observational strategy enables a comparison of flow structures over a broad range of spatial scales, from the size of the circuit itself ( 100 km) to small-scale turbulent fluxes ( 3 m). It is found that many aspects of the resolved flow converge successfully towards the observations with resolution if sampling uncertainty is allowed for, including the area-average vorticity and divergence measures and the narrowest observed cross-frontal width. In addition, there is a gradual handover from parametrised to resolved turbulent fluxes of moisture and momentum as cold-sector boundary-layer convective motions behind the front become partially-resolved in the highest resolution simulations. In contrast, the structure of frontal rainbands associated with shear instability along the front does not appear to converge with resolution, indicating that the mechanism of the frontal instability may not be well represented in the simulations. The parametrised turbulent fluxes associated with subgrid-scale shear-driven turbulence ahead of the front also do not converge on the observations.

  8. Overpressure and fluid flow in the new jersey continental slope: implications for slope failure and cold seeps

    PubMed

    Dugan; Flemings

    2000-07-14

    Miocene through Pleistocene sediments on the New Jersey continental slope (Ocean Drilling Program Site 1073) are undercompacted (porosity between 40 and 65%) to 640 meters below the sea floor, and this is interpreted to record fluid pressures that reach 95% of the lithostatic stress. A two-dimensional model, where rapid Pleistocene sedimentation loads permeable sandy silt of Miocene age, successfully predicts the observed pressures. The model describes how lateral pressure equilibration in permeable beds produces fluid pressures that approach the lithostatic stress where overburden is thin. This transfer of pressure may cause slope failure and drive cold seeps on passive margins around the world.

  9. Improved parameterization of marine ice dynamics and flow instabilities for simulation of the Austfonna ice cap using a large-scale ice sheet model

    NASA Astrophysics Data System (ADS)

    Dunse, T.; Greve, R.; Schuler, T.; Hagen, J. M.; Navarro, F.; Vasilenko, E.; Reijmer, C.

    2009-12-01

    The Austfonna ice cap covers an area of 8120 km2 and is by far the largest glacier on Svalbard. Almost 30% of the entire area is grounded below sea-level, while the figure is as large as 57% for the known surge-type basins in particular. Marine ice dynamics, as well as flow instabilities presumably control flow regime, form and evolution of Austfonna. These issues are our focus in numerical simulations of the ice cap. We employ the thermodynamic, large-scale ice sheet model SICOPOLIS (http://sicopolis.greveweb.net/) which is based on the shallow-ice approximation. We present improved parameterizations of (a) the marine extent and calving and (b) processes that may initiate flow instabilities such as switches from cold to temperate basal conditions, surface steepening and hence, increases in driving stress, enhanced sliding or deformation of unconsolidated marine sediments and diminishing ice thicknesses towards flotation thickness. Space-borne interferometric snapshots of Austfonna revealed a velocity structure of a slow moving polar ice cap (< 10m/a) interrupted by distinct fast flow units with velocities in excess of 100m/a. However, observations of flow variability are scarce. In spring 2008, we established a series of stakes along the centrelines of two fast-flowing units. Repeated DGPS and continuous GPS measurements of the stake positions give insight in the temporal flow variability of these units and provide constrains to the modeled surface velocity field. Austfonna’s thermal structure is described as polythermal. However, direct measurements of the temperature distribution is available only from one single borehole at the summit area. The vertical temperature profile shows that the bulk of the 567m thick ice column is cold, only underlain by a thin temperate basal layer of approximately 20m. To acquire a spatially extended picture of the thermal structure (and bed topography), we used low-frequency (20 MHz) GPR profiling across the ice cap and the

  10. Improved computational treatment of transonic flow about swept wings

    NASA Technical Reports Server (NTRS)

    Ballhaus, W. F.; Bailey, F. R.; Frick, J.

    1976-01-01

    Relaxation solutions to classical three-dimensional small-disturbance (CSD) theory for transonic flow about lifting swept wings are reported. For such wings, the CSD theory was found to be a poor approximation to the full potential equation in regions of the flow field that are essentially two-dimensional in a plane normal to the sweep direction. The effect of this deficiency on the capture of embedded shock waves in terms of (1) the conditions under which shock waves can exist and (2) the relations they must satisfy when they do exist is emphasized. A modified small-disturbance (MSD) equation, derived by retaining two previously neglected terms, was proposed and shown to be a consistent approximation to the full potential equation over a wider range of sweep angles. The effect of these extra terms is demonstrated by comparing CSD, MSD, and experimental wing surface pressures.

  11. Improvement of Unbalanced Load Flow Program for Large Power Systems

    NASA Astrophysics Data System (ADS)

    Imai, Shinichi; Suzuki, Haruhiko; Iba, Kenji; Fujiwara, Shuhei

    The idea of unbalanced power flow calculation was proposed many years ago. At that time, however, the needs for such techniques was not an argent issue. But modern power system networks are comprised of long untransposed transmission lines. Therefore, for some kind of analysis, it is now almost impossible to treat a system as though it were a symmetrical network. The aims of most previous studies were oriented to solve voltage/current imbalance in local or small system because local imbalance was a serious concern. This is still an important issue, but more recently our needs have become concentrated on practical bulk power systems, since principal EHV lines are entirely untransposed. Following such a background, we have developed a practical unbalanced load flow program. This program was developed for steady state analysis of large scale of practical networks under many possible unbalanced conditions.

  12. Flow improvement caused by agents who ignore traffic rules.

    PubMed

    Baek, Seung Ki; Minnhagen, Petter; Bernhardsson, Sebastian; Choi, Kweon; Kim, Beom Jun

    2009-07-01

    A system of agents moving along a road in both directions is studied numerically within a cellular-automata formulation. An agent steps to the right with probability q or to the left with 1-q when encountering other agents. Our model is restricted to two agent types, traffic-rule abiders (q=1) and traffic-rule ignorers (q=1/2) , and the traffic flow, resulting from the interaction between these two types of agents, which is obtained as a function of density and relative fraction. The risk for jamming at a fixed density, when starting from a disordered situation, is smaller when every agent abides by a traffic rule than when all agents ignore the rule. Nevertheless, the absolute minimum occurs when a small fraction of ignorers are present within a majority of abiders. The characteristic features for the spatial structure of the flow pattern are obtained and discussed.

  13. Determination of Mercury in Aqueous and Geologic Materials by Continuous Flow-Cold Vapor-Atomic Fluorescence Spectrometry (CVAFS)

    USGS Publications Warehouse

    Hageman, Philip L.

    2007-01-01

    New methods for the determination of total mercury in geologic materials and dissolved mercury in aqueous samples have been developed that will replace the methods currently (2006) in use. The new methods eliminate the use of sodium dichromate (Na2Cr2O7 ?2H2O) as an oxidizer and preservative and significantly lower the detection limit for geologic and aqueous samples. The new methods also update instrumentation from the traditional use of cold vapor-atomic absorption spectrometry to cold vapor-atomic fluorescence spectrometry. At the same time, the new digestion procedures for geologic materials use the same size test tubes, and the same aluminum heating block and hot plate as required by the current methods. New procedures for collecting and processing of aqueous samples use the same procedures that are currently (2006) in use except that the samples are now preserved with concentrated hydrochloric acid/bromine monochloride instead of sodium dichromate/nitric acid. Both the 'old' and new methods have the same analyst productivity rates. These similarities should permit easy migration to the new methods. Analysis of geologic and aqueous reference standards using the new methods show that these procedures provide mercury recoveries that are as good as or better than the previously used methods.

  14. Local cold acclimation of the hand impairs thermal responses of the finger without improving hand neuromuscular function.

    PubMed

    Geurts, C L M; Sleivert, G G; Cheung, S S

    2005-01-01

    To investigate the effects of cold acclimation on the thermal response and neuromuscular function of the hand. Ten healthy subjects [three female, seven male, age (mean +/- SD): 27.9 +/- 7.9 years] immersed their right hand in 8 degrees C water for 30 min, 5 days a week for 3 weeks. On the first and the last day, neuromuscular function of the first dorsal interosseus (FDI) muscle was tested. There was no significant change in maximal voluntary contraction strength or evoked contractile characteristics of the FDI after cold acclimation. Minimum finger temperature decreased significantly from 10.6 +/- 1.2 to 9.3 +/- 0.8 degrees C after 3 weeks (P < 0.01), with most of the decrease occurring after a single exposure. Mean finger temperature dropped significantly from 14.2 +/- 1.9 to 11.7 +/- 1.4 degrees C following cold acclimation (P < 0.05), with 90% of this adaptation occurring after 5 days. Onset time of cold-induced vasodilatation increased from 446 +/- 171 to 736 +/- 384 s (P < 0.05) and the amplitude decreased from 5.3 +/- 3.2 to 2.5 +/- 2.1 degrees C (P < 0.05). This was significantly different from the control group, who immersed their right hand on the first and last days only. These data suggest that cold acclimation does not enhance hand temperature or function but may put the hands at a greater risk of cold injury when exposed to the cold.

  15. Zinc Acetate Lozenges May Improve the Recovery Rate of Common Cold Patients: An Individual Patient Data Meta-Analysis.

    PubMed

    Hemilä, Harri; Fitzgerald, James T; Petrus, Edward J; Prasad, Ananda

    2017-01-01

    A previous meta-analysis of 3 zinc acetate lozenge trials estimated that colds were on average 40% shorter for the zinc groups. However, the duration of colds is a time outcome, and survival analysis may be a more informative approach. The objective of this individual patient data (IPD) meta-analysis was to estimate the effect of zinc acetate lozenges on the rate of recovery from colds. We analyzed IPD for 3 randomized placebo-controlled trials in which 80-92 mg/day of elemental zinc were administered as zinc acetate lozenges to 199 common cold patients. We used mixed-effects Cox regression to estimate the effect of zinc. Patients administered zinc lozenges recovered faster by rate ratio 3.1 (95% confidence interval, 2.1-4.7). The effect was not modified by age, sex, race, allergy, smoking, or baseline common cold severity. On the 5th day, 70% of the zinc patients had recovered compared with 27% of the placebo patients. Accordingly, 2.6 times more patients were cured in the zinc group. The difference also corresponds to the number needed to treat of 2.3 on the 5th day. None of the studies observed serious adverse effects of zinc. The 3-fold increase in the rate of recovery from the common cold is a clinically important effect. The optimal formulation of zinc lozenges and an ideal frequency of their administration should be examined. Given the evidence of efficacy, common cold patients may be instructed to try zinc acetate lozenges within 24 hours of onset of symptoms.

  16. Improved Flow-Field Structures for Direct Methanol Fuel Cells

    SciTech Connect

    Gurau, Bogdan

    2013-05-31

    The direct methanol fuel cell (DMFC) is ideal if high energy-density liquid fuels are required. Liquid fuels have advantages over compressed hydrogen including higher energy density and ease of handling. Although state-of-the-art DMFCs exhibit manageable degradation rates, excessive fuel crossover diminishes system energy and power density. Although use of dilute methanol mitigates crossover, the concomitant lowering of the gross fuel energy density (GFED) demands a complex balance-of-plant (BOP) that includes higher flow rates, external exhaust recirculation, etc. An alternative approach is redesign of the fuel delivery system to accommodate concentrated methanol. NuVant Systems Inc. (NuVant) will maximize the GFED by design and assembly of a DMFC that uses near neat methanol. The approach is to tune the diffusion of highly concentrated methanol (to the anode catalytic layer) to the back-diffusion of water formed at the cathode (i.e. in situ generation of dilute methanol at the anode layer). Crossover will be minimized without compromising the GFED by innovative integration of the anode flow-field and the diffusion layer. The integrated flow-field-diffusion-layers (IFDLs) will widen the current and potential DMFC operating ranges and enable the use of cathodes optimized for hydrogen-air fuel cells.

  17. Elements of an improved model of debris-flow motion

    USGS Publications Warehouse

    Iverson, R.M.

    2009-01-01

    A new depth-averaged model of debris-flow motion describes simultaneous evolution of flow velocity and depth, solid and fluid volume fractions, and pore-fluid pressure. Non-hydrostatic pore-fluid pressure is produced by dilatancy, a state-dependent property that links the depth-averaged shear rate and volumetric strain rate of the granular phase. Pore-pressure changes caused by shearing allow the model to exhibit rate-dependent flow resistance, despite the fact that the basal shear traction involves only rate-independent Coulomb friction. An analytical solution of simplified model equations shows that the onset of downslope motion can be accelerated or retarded by pore-pressure change, contingent on whether dilatancy is positive or negative. A different analytical solution shows that such effects will likely be muted if downslope motion continues long enough, because dilatancy then evolves toward zero, and volume fractions and pore pressure concurrently evolve toward steady states. ?? 2009 American Institute of Physics.

  18. Common cold

    MedlinePlus

    ... this page: //medlineplus.gov/ency/article/000678.htm Common cold To use the sharing features on this page, please enable JavaScript. The common cold most often causes a runny nose, nasal congestion, ...

  19. Review of passive shear-flow control research for improved subsonic and supersonic combustion

    SciTech Connect

    Schadow, K.C.; Gutmark, E.

    1989-01-01

    Shear-flow investigations have been conducted in the high-Re, turbulent initial-condition combustion regime representative of flow configurations encountered in ramjets and in supersonic plumes. Large-scale vortical structures were identified and characterized in both nonreacting and combustion-reaction experimental conditions; attention was given to these structures' role in mixing, and their breakup into fine-scale turbulence. Shear-flow/combustion control was obtained by actively enlisting duct acoustics and passively employing noncircular flow cross-sections. The investigations were extended to supersonic shear flows, yielding improved mixing for supersonic combustion. 44 refs.

  20. The effect of screw rotating speed on mass flow rate, temperature, viscosity, mooney scorch time anddie swell of cold feed rubber blending prepared by qsm 200 extruder machine

    NASA Astrophysics Data System (ADS)

    Elmiawan, P.; Saryanto, H.; Sebayang, D.

    2017-05-01

    The effect of screw rotating speed on cold feed rubber blending production were evaluated. The specimens were prepared by using QSM 200 extruding machine with variable screw rotating speed 4, 6, 8, 10, 12, 16 and 20 RPM. The temperature set in the screw and head of the barrel was around 80 °C by using Temperature Controll Unit (TCU), and was set around 70°C in zone 1 and 2. Mooney Viscometer was used to evaluate the viscosity and Mooney Scorch Time of cold rubber blending before and after extruding process. In addition, the dynamic rubber process analyzer was used to evaluate the Die Swell of rubber blending after extruding process. The result indicated that the increase of screw rotating speed has a significant effect to increase the flow rate, temperature and the viscosity of the rubber blending. Otherwise, the Mooney Scorch Time (MST) increases due to the decrease of the screw rotating speed. It does not have a significant effect to the die swell of rubber blending.

  1. High resolution FTIR spectroscopic study of the ν4 band of CH 3CHF 2 enclosed in a flow of cold N 2 gas

    NASA Astrophysics Data System (ADS)

    Appadoo, Dominique R. T.; Robertson, Evan G.; McNaughton, Don

    2003-01-01

    An enclosive flow cooling (EFC) cell has been constructed, and coupled to a Brüker IFS 120HR high resolution Fourier transform spectrometer to record rotationally cold absorption spectra of gases of atmospheric interest at high spectral resolution. The new system has been characterized using N 2O, revealing that rotational temperatures as cold as 110 K are readily attainable using liquid nitrogen as a cryogen. Infrared spectra of the ν4 band of 1,1-difluoroethane (R152a), CH 3CHF 2, cooled in the EFC cell have been measured at a resolution of 0.0019 cm-1. Eight hundred and twenty rovibrational transitions of the weak ν4 band with 2⩽ J'⩽46 and Kc'⩽16 were assigned and fitted to Watson's A-reduced Hamiltonian. The ν4 CH 3 symmetric deformation ( a/c-type) was found to be coupled to the ν13 asymmetric deformation ( b-type) via an a-axis Coriolis interaction. In the ensuing analysis, values of spectroscopic constants were obtained for both the ν4 and dark ν13 states. Supporting ab initio calculations up to the MP2/TZV+(3 df,3 p) level are presented.

  2. Cold Sore

    MedlinePlus

    ... genitals. Most people who are infected with the virus that causes cold sores never develop signs and symptoms. Cold sores ... an infection — test positive for evidence of the virus that causes cold sores. People who have weakened immune systems are ...

  3. An improved lambda-scheme for one-dimensional flows

    NASA Technical Reports Server (NTRS)

    Moretti, G.; Dipiano, M. T.

    1983-01-01

    A code for the calculation of one-dimensional flows is presented, which combines a simple and efficient version of the lambda-scheme with tracking of discontinuities. The latter is needed to identify points where minor departures from the basic integration scheme are applied to prevent infiltration of numerical errors. Such a tracking is obtained via a systematic application of Boolean algebra. It is, therefore, very efficient. Fifteen examples are presented and discussed in detail. The results are exceptionally good. All discontinuites are captured within one mesh interval.

  4. Improved Turbine Blade Cooling Using Endwall Flow Modifications

    DTIC Science & Technology

    2007-11-02

    ANEMOMETER AND PROBE 21 3.3 PRESSURE TRANSDUCER 22 3.4 PITOT TUBE 23 3.5 KIEL PROBE 23 3.6 LASER DOPPLER ANEMOMETRY 24 4 FLOW VISUALIZATION 26 4.1 OIL AND...blades and nozzle vanes ) and the endwalls (Ito, 1978). One common cooling method is "film cooling" in which cool air is bled from the compressor and...demodulator outputs to a voltage which is proportional to the pressure difference across the diaphragm. A pitot tube was placed in the wind tunnel and

  5. Improved Flux Formulations for Unsteady Low Mach Number Flows

    DTIC Science & Technology

    2012-06-01

    flows (as, for example, the combusted exhaust plume from an aircraft engine). One effective way for expressing a general iterative method is through a...pseudo-Mach number to physical-Mach number and the ratio of specific heats : 2 1 1p p p M M (5) where 2 2 2 2 minmin max( , , ),1p i uM M M M (6...performed with the CRUNCH CFD ® code, developed at CRAFT Tech12-15. The candidate flux formulations for unsteady low Mach 8 American Institute of

  6. Improvement of transient stability using unified power flow controller

    SciTech Connect

    Mihalic, R.; Zunko, P.; Povh, D.

    1996-01-01

    The aim of the paper is to analyze the effect of an Unified Power Flow Controller (UPFC) on transient stability margin enhancement of a longitudinal system. To utilize the UPFC possibilities fully, the three controllable UPFC parameters were determined during the digital simulation process performed by the NETOMAC simulation program. The basis for determination of the suitable damping strategy and for determination of the optimal UPFC parameters is a mathematical model, which describes the interdependence between longitudinal transmission system parameters, operating conditions and UPFC parameters in the form of analytical equations. On the basis of the mathematical model, the theoretical UPFC limits were also detected, and their appearance explained.

  7. Comparative proteomic and metabolomic analyses reveal mechanisms of improved cold stress tolerance in bermudagrass (Cynodon dactylon (L.) Pers.) by exogenous calcium.

    PubMed

    Shi, Haitao; Ye, Tiantian; Zhong, Bao; Liu, Xun; Chan, Zhulong

    2014-11-01

    As an important second messenger, calcium is involved in plant cold stress response, including chilling (<20 °C) and freezing (<0 °C). In this study, exogenous application of calcium chloride (CaCl2 ) improved both chilling and freezing stress tolerances, while ethylene glycol-bis-(β-aminoethyl) ether-N,N,N,N-tetraacetic acid (EGTA) reversed CaCl2 effects in bermudagrass (Cynodon dactylon (L.) Pers.). Physiological analyses showed that CaCl2 treatment alleviated the reactive oxygen species (ROS) burst and cell damage triggered by chilling stress, via activating antioxidant enzymes, non-enzymatic glutathione antioxidant pool, while EGTA treatment had the opposite effects. Additionally, comparative proteomic analysis identified 51 differentially expressed proteins that were enriched in redox, tricarboxylicacid cycle, glycolysis, photosynthesis, oxidative pentose phosphate pathway, and amino acid metabolisms. Consistently, 42 metabolites including amino acids, organic acids, sugars, and sugar alcohols were regulated by CaCl2 treatment under control and cold stress conditions, further confirming the common modulation of CaCl2 treatment in carbon metabolites and amino acid metabolism. Taken together, this study reported first evidence of the essential and protective roles of endogenous and exogenous calcium in bermudagrass response to cold stress, partially via activation of the antioxidants and modulation of several differentially expressed proteins and metabolic homeostasis in the process of cold acclimation. © 2014 Institute of Botany, Chinese Academy of Sciences.

  8. The Role of Flow Field Computation in Improving Turbomachinery.

    DTIC Science & Technology

    1986-06-01

    sad total pressure within Solls-Royce t9 design turbine blade %hopes. loan. The comressors need in engines designed in Moruigesn and ReJily. 7 0 ) wrote... engine improve efficiency. In one case, blading designed specific fuel conaumption improved by some I Z. by NOTS for a mall Industrial turbine anufact...the corners Nost small aeronautical gas turbines have there- between wall and blade , and in due course also for fore chosen to use several axial stages

  9. Flowing Hot or Cold: User-Friendly Computational Models of Terrestrial and Planetary Lava Channels and Lakes

    NASA Astrophysics Data System (ADS)

    Sakimoto, S. E. H.

    2016-12-01

    Planetary volcanism has redefined what is considered volcanism. "Magma" now may be considered to be anything from the molten rock familiar at terrestrial volcanoes to cryovolcanic ammonia-water mixes erupted on an outer solar system moon. However, even with unfamiliar compositions and source mechanisms, we find familiar landforms such as volcanic channels, lakes, flows, and domes and thus a multitude of possibilities for modeling. As on Earth, these landforms lend themselves to analysis for estimating storage, eruption and/or flow rates. This has potential pitfalls, as extension of the simplified analytic models we often use for terrestrial features into unfamiliar parameter space might yield misleading results. Our most commonly used tools for estimating flow and cooling have tended to lag significantly behind state-of-the-art; the easiest methods to use are neither realistic or accurate, but the more realistic and accurate computational methods are not simple to use. Since the latter computational tools tend to be both expensive and require a significant learning curve, there is a need for a user-friendly approach that still takes advantage of their accuracy. One method is use of the computational package for generation of a server-based tool that allows less computationally inclined users to get accurate results over their range of input parameters for a given problem geometry. A second method is to use the computational package for the generation of a polynomial empirical solution for each class of flow geometry that can be fairly easily solved by anyone with a spreadsheet. In this study, we demonstrate both approaches for several channel flow and lava lake geometries with terrestrial and extraterrestrial examples and compare their results. Specifically, we model cooling rectangular channel flow with a yield strength material, with applications to Mauna Loa, Kilauea, Venus, and Mars. This approach also shows promise with model applications to lava lakes, magma

  10. Aerosil for the improvement of the flow behavior of powdered substances

    NASA Technical Reports Server (NTRS)

    1981-01-01

    The tendency of powdered substances to agglomerate and stick together is studied. The highly dispersed silicic acid Aerosil (tradename) is studied as an agent to improve the free flowing characteristics of powdered materials. It was concluded that the use of Aerosil 200, Aerosil R 972, aluminum oxide C and sylicic acid D 17 as flow agents caused broad improvements in the flow properties of powders. Additionally, the sifting, dispersion, and spray behavior, as well as the grinding and air separation characteristics of powders were improved.

  11. Improving the performance of biomimetic hair-flow sensors by electrostatic spring softening

    NASA Astrophysics Data System (ADS)

    Droogendijk, H.; Bruinink, C. M.; Sanders, R. G. P.; Dagamseh, A. M. K.; Wiegerink, R. J.; Krijnen, G. J. M.

    2012-06-01

    We report improvements in the detection limit and responsivity of biomimetic hair-flow sensors by electrostatic spring softening. Applying a dc-bias voltage to our capacitive flow sensors results in a reduced sensory threshold, improving the mechanical transfer and flow detection limit by more than 6 dB. We further show that the sensor's responsivity for airflows is also improved on application of high-frequency ac-bias voltages to the sensor's capacitive structures with little sensitivity to the bias frequency.

  12. MoFlow: visualizing conformational changes in molecules as molecular flow improves understanding

    PubMed Central

    2015-01-01

    Background Current visualizations of molecular motion use a Timeline-analogous representation that conveys "first the molecule was shaped like this, then like this...". This scheme is orthogonal to the Pathline-like human understanding of motion "this part of the molecule moved from here to here along this path". We present MoFlow, a system for visualizing molecular motion using a Pathline-analogous representation. Results The MoFlow system produces high-quality renderings of molecular motion as atom pathlines, as well as interactive WebGL visualizations, and 3D printable models. In a preliminary user study, MoFlow representations are shown to be superior to canonical representations for conveying molecular motion. Conclusions Pathline-based representations of molecular motion are more easily understood than timeline representations. Pathline representations provide other advantages because they represent motion directly, rather than representing structure with inferred motion. PMID:26361501

  13. Hot versus cold: The dichotomy in spherical accretion of cooling flows onto supermassive black holes in elliptical galaxies, galaxy groups, and clusters

    SciTech Connect

    Guo, Fulai; Mathews, William G.

    2014-01-10

    Feedback heating from active galactic nuclei (AGNs) has been commonly invoked to suppress cooling flows predicted in hot gas in elliptical galaxies, galaxy groups, and clusters. Previous studies have focused on if and how AGN feedback heats the gas but have little paid attention to its triggering mechanism. Using spherically symmetric simulations, we investigate how large-scale cooling flows are accreted by central supermassive black holes (SMBHs) in eight well-observed systems and find an interesting dichotomy. In massive clusters, the gas develops a central cooling catastrophe within about the cooling time (typically ∼100-300 Myr), resulting in cold-mode accretion onto SMBHs. However, in our four simulated systems on group and galaxy scales at a low metallicity Z = 0.3 Z {sub ☉}, the gas quickly settles into a long-term state that has a cuspy central temperature profile extending to several tens to about 100 pc. At the more realistic solar metallicity, two groups (with R {sub e} ∼ 4 kpc) still host the long-term, hot-mode accretion. Both accretion modes naturally appear in our idealized calculations where only cooling, gas inflow, and compressional heating are considered. The long-term, hot-mode accretion is maintained by the quickly established closeness between the timescales of these processes, preferably in systems with low gas densities, low gas metallicities, and importantly, compact central galaxies, which result in strong gravitational acceleration and compressional heating at the intermediate radii. Our calculations predict that central cuspy temperature profiles appear more often in smaller systems than galaxy clusters, which instead often host significant cold gas and star formation.

  14. Coupled prediction of flood response and debris flow initiation during warm- and cold-season events in the Southern Appalachians, USA

    NASA Astrophysics Data System (ADS)

    Tao, J.; Barros, A. P.

    2014-01-01

    Debris flows associated with rainstorms are a frequent and devastating hazard in the Southern Appalachians in the United States. Whereas warm-season events are clearly associated with heavy rainfall intensity, the same cannot be said for the cold-season events. Instead, there is a relationship between large (cumulative) rainfall events independently of season, and thus hydrometeorological regime, and debris flows. This suggests that the dynamics of subsurface hydrologic processes play an important role as a trigger mechanism, specifically through soil moisture redistribution by interflow. We further hypothesize that the transient mass fluxes associated with the temporal-spatial dynamics of interflow govern the timing of shallow landslide initiation, and subsequent debris flow mobilization. The first objective of this study is to investigate this relationship. The second objective is to assess the physical basis for a regional coupled flood prediction and debris flow warning system. For this purpose, uncalibrated model simulations of well-documented debris flows in headwater catchments of the Southern Appalachians using a 3-D surface-groundwater hydrologic model coupled with slope stability models are examined in detail. Specifically, we focus on two vulnerable headwater catchments that experience frequent debris flows, the Big Creek and the Jonathan Creek in the Upper Pigeon River Basin, North Carolina, and three distinct weather systems: an extremely heavy summertime convective storm in 2011; a persistent winter storm lasting several days; and a severe winter storm in 2009. These events were selected due to the optimal availability of rainfall observations; availability of detailed field surveys of the landslides shortly after they occurred, which can be used to evaluate model predictions; and because they are representative of events that cause major economic losses in the region. The model results substantiate that interflow is a useful prognostic of conditions

  15. Prediction of cavitation performance and choking flow limit of inducers for cold water and for fluids with thermodynamic effect

    NASA Astrophysics Data System (ADS)

    Sauvage-Boutar, E.; Desclaux, J.

    1990-07-01

    Two methods of prediction of partial cavitation in inducers of rocket engine turbopumps have been developed. The first one is an analytical method previously developed to predict minimum NPSH (inlet total head minus vapor pressure) and the choking flow limit which was modified to include the computation of blade and boundary layer blockage. The second one is a method based on the work of Moore and Ruggeri (1969). This method takes into account thermodynamic effect for the prediction of the cavitation parameter Ki. For the choking flow limit, the first method can be extended to cryogenic fluids. Comparisons with available experimental data obtained with VULCAIN inducer pumping water and liquid hydrogen are presented.

  16. Improved algorithms for circulation-control airfoils in transonic flow

    NASA Technical Reports Server (NTRS)

    Dvorak, Frank A.; Strash, Daniel J.; York, Brian J.; Dash, Sanford M.

    1987-01-01

    A zonal model for aerodynamic analysis of two-dimensional transonic circulation control airfoils has been developed. The present approach combines a transonic full potential method for the global flow field and an integral boundary layer method for regions of the airfoil excluding the wall jet with a parabolized Navier-Stokes code for resolving the wall jet region beyond the slot. Existing methods suffer from two deficiencies: the insensitivity of the calculation to small changes in the Coanda surface geometry; and the inability to predict the shock structure of the underexpanded supersonic wall jets. The present wall jet procedure involves a pressure-split approach in the streamwise sense to enable noniterative solution of the coupled continuity and normal momentum equations for increased surface sensitivity and allows for expansion of applications to sonic slot exit conditions. Encouraging results are obtained in comparison with experimental data for two circulation airfoils with subsonic wall jets.

  17. Improved algorithms for circulation-control airfoils in transonic flow

    NASA Technical Reports Server (NTRS)

    Dvorak, Frank A.; Strash, Daniel J.; York, Brian J.; Dash, Sanford M.

    1987-01-01

    A zonal model for aerodynamic analysis of two-dimensional transonic circulation control airfoils has been developed. The present approach combines a transonic full potential method for the global flow field and an integral boundary layer method for regions of the airfoil excluding the wall jet with a parabolized Navier-Stokes code for resolving the wall jet region beyond the slot. Existing methods suffer from two deficiencies: the insensitivity of the calculation to small changes in the Coanda surface geometry; and the inability to predict the shock structure of the underexpanded supersonic wall jets. The present wall jet procedure involves a pressure-split approach in the streamwise sense to enable noniterative solution of the coupled continuity and normal momentum equations for increased surface sensitivity and allows for expansion of applications to sonic slot exit conditions. Encouraging results are obtained in comparison with experimental data for two circulation airfoils with subsonic wall jets.

  18. An improved flow cytometry assay to monitor phagosome acidification.

    PubMed

    Colas, Chloé; Menezes, Shinelle; Gutiérrez-Martínez, Enric; Péan, Claire B; Dionne, Marc S; Guermonprez, Pierre

    2014-10-01

    Phago-lysosome formation is important for cell-autonomous immunity to intracellular pathogens, antigen presentation and metabolism. A hallmark feature of phago-lysosomal compartments is that they undergo progressive luminal acidification controlled by the activation of vacuolar V-ATPase. Acidification is required for many enzymatic processes taking place in phago-lysosomes, like proteolysis, and supports the microbicidal activity of macrophages. Here we present a new quantitative methodology to assess phagosome acidification by flow cytometry based on the use of bi-fluorescent particles. This method relies on the use of UV polystyrene beads labelled with the acid sensor pHrodo-succinimidyl ester (pHrodo(TM) SE red) and enables us to dissociate particle association with phagocytes from their engulfment in acidified compartments. This methodology is well suited to monitor the acidification of phagosomes formed in vivo after fluorescent bead administration.

  19. Improving the health forecasting alert system for cold weather and heat-waves in England: a case-study approach using temperature-mortality relationships

    NASA Astrophysics Data System (ADS)

    Masato, Giacomo; Cavany, Sean; Charlton-Perez, Andrew; Dacre, Helen; Bone, Angie; Carmicheal, Katie; Murray, Virginia; Danker, Rutger; Neal, Rob; Sarran, Christophe

    2015-04-01

    The health forecasting alert system for cold weather and heatwaves currently in use in the Cold Weather and Heatwave plans for England is based on 5 alert levels, with levels 2 and 3 dependent on a forecast or actual single temperature action trigger. Epidemiological evidence indicates that for both heat and cold, the impact on human health is gradual, with worsening impact for more extreme temperatures. The 60% risk of heat and cold forecasts used by the alerts is a rather crude probabilistic measure, which could be substantially improved thanks to the state-of-the-art forecast techniques. In this study a prototype of a new health forecasting alert system is developed, which is aligned to the approach used in the Met Office's (MO) National Severe Weather Warning Service (NSWWS). This is in order to improve information available to responders in the health and social care system by linking temperatures more directly to risks of mortality, and developing a system more coherent with other weather alerts. The prototype is compared to the current system in the Cold Weather and Heatwave plans via a case-study approach to verify its potential advantages and shortcomings. The prototype health forecasting alert system introduces an "impact vs likelihood matrix" for the health impacts of hot and cold temperatures which is similar to those used operationally for other weather hazards as part of the NSWWS. The impact axis of this matrix is based on existing epidemiological evidence, which shows an increasing relative risk of death at extremes of outdoor temperature beyond a threshold which can be identified epidemiologically. The likelihood axis is based on a probability measure associated with the temperature forecast. The new method is tested for two case studies (one during summer 2013, one during winter 2013), and compared to the performance of the current alert system. The prototype shows some clear improvements over the current alert system. It allows for a much greater

  20. Integration of selective breeding and vaccination to improve disease resistance in aquaculture: Application to control bacterial cold water disease

    USDA-ARS?s Scientific Manuscript database

    Bacterial cold water disease (BCWD) is a frequent cause of elevated mortality in rainbow trout and the development of effective control strategies is a priority within the U.S. A goal of the NCCCWA breeding program is to produce germplasm with superior growth and survival following exposure to infe...

  1. Weighted ssGBLUP improves genomic selection accuracy for bacterial cold water disease resistance in a rainbow trout population

    USDA-ARS?s Scientific Manuscript database

    The objective of this study was to compare methods for genomic evaluation in a Rainbow Trout (Oncorhynchus mykiss) population for survival when challenged by Flavobacterium psychrophilum, the causative agent of bacterial cold water disease (BCWD). The used methods were: 1)regular ssGBLUP that assume...

  2. Ultraviolet-B radiation induced crosslinking improves physical properties of cold- and warm-water fish gelatin gels and films

    USDA-ARS?s Scientific Manuscript database

    Cold- and warm-water fish gelatin granules were exposed to ultraviolet-B radiation for doses up to 29.7 J/cm2. Solutions and films were prepared from the granules. Gel electrophoresis and refractive index were used to examine changes in molecular weight of the samples. Also, the gel strength and rhe...

  3. Cold-water immersion decreases cerebral oxygenation but improves recovery after intermittent-sprint exercise in the heat.

    PubMed

    Minett, G M; Duffield, R; Billaut, F; Cannon, J; Portus, M R; Marino, F E

    2014-08-01

    This study examined the effects of post-exercise cooling on recovery of neuromuscular, physiological, and cerebral hemodynamic responses after intermittent-sprint exercise in the heat. Nine participants underwent three post-exercise recovery trials, including a control (CONT), mixed-method cooling (MIX), and cold-water immersion (10 °C; CWI). Voluntary force and activation were assessed simultaneously with cerebral oxygenation (near-infrared spectroscopy) pre- and post-exercise, post-intervention, and 1-h and 24-h post-exercise. Measures of heart rate, core temperature, skin temperature, muscle damage, and inflammation were also collected. Both cooling interventions reduced heart rate, core, and skin temperature post-intervention (P < 0.05). CWI hastened the recovery of voluntary force by 12.7 ± 11.7% (mean ± SD) and 16.3 ± 10.5% 1-h post-exercise compared to MIX and CONT, respectively (P < 0.01). Voluntary force remained elevated by 16.1 ± 20.5% 24-h post-exercise after CWI compared to CONT (P < 0.05). Central activation was increased post-intervention and 1-h post-exercise with CWI compared to CONT (P < 0.05), without differences between conditions 24-h post-exercise (P > 0.05). CWI reduced cerebral oxygenation compared to MIX and CONT post-intervention (P < 0.01). Furthermore, cooling interventions reduced cortisol 1-h post-exercise (P < 0.01), although only CWI blunted creatine kinase 24-h post-exercise compared to CONT (P < 0.05). Accordingly, improvements in neuromuscular recovery after post-exercise cooling appear to be disassociated with cerebral oxygenation, rather reflecting reductions in thermoregulatory demands to sustain force production. © 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  4. Coal flow aids reduce coke plant operating costs and improve production rates

    SciTech Connect

    Bedard, R.A.; Bradacs, D.J.; Kluck, R.W.; Roe, D.C.; Ventresca, B.P.

    2005-06-01

    Chemical coal flow aids can provide many benefits to coke plants, including improved production rates, reduced maintenance and lower cleaning costs. This article discusses the mechanisms by which coal flow aids function and analyzes several successful case histories. 2 refs., 10 figs., 1 tab.

  5. Using Sap Flow Monitoring for Improved Process-based Ecohydrologic Understanding 2022

    USDA-ARS?s Scientific Manuscript database

    Sap flow measurements can be an important tool for unraveling the complex web of ecosystem fluxes, especially when it is combined with other measurements like eddy covariance, isotopes, remote sensing, etc. In this talk, we will demonstrate how sap flow measurements have improved our process-level u...

  6. Measurement of Gas Velocities in the Presence of Solids in the Riser of a Cold Flow Circulating Fluidized Bed

    SciTech Connect

    Spenik, J.; Ludlow, J.C.; Compston, R.; Breault, R.W.

    2007-01-01

    The local gas velocity and the intensity of the gas turbulence in a gas/solid flow are a required measurement in validating the gas and solids flow structure predicted by computational fluid dynamic (CFD) models in fluid bed and transport reactors. The high concentration and velocities of solids, however, make the use of traditional gas velocity measurement devices such as pitot tubes, hot wire anemometers and other such devices difficult. A method of determining these velocities has been devised at the National Energy Technology Laboratory employing tracer gas. The technique developed measures the time average local axial velocity gas component of a gas/solid flow using an injected tracer gas which induces changes in the heat transfer characteristics of the gas mixture. A small amount of helium is injected upstream a known distance from a self-heated thermistor. The thermistor, protected from the solids by means of a filter, is exposed to gases that are continuously extracted from the flow. Changes in the convective heat transfer characteristics of the gas are indicated by voltage variations across a Wheatstone bridge. When pulsed injections of helium are introduced to the riser flow the change in convective heat transfer coefficient of the gas can be rapidly and accurately determined with this instrument. By knowing the separation distance between the helium injection point and the thermistor extraction location as well as the time delay between injection and detection, the gas velocity can easily be calculated. Variations in the measured gas velocities also allow the turbulence intensity of the gas to be estimated.

  7. Improvement of flavor and viscosity in hot and cold break tomato juice and sauce by peel removal.

    PubMed

    Mirondo, Rita; Barringer, Sheryl

    2015-01-01

    Tomatoes are typically not peeled before being made into juice but the peels contain enzymes that affect the odor, flavor, and viscosity of the juice. The peels are removed in the finisher, but their presence during the break process may affect quality. Juice was processed from peeled and unpeeled tomatoes using hot or cold break. The juices were pasteurized by high temperature short time (HTST), low temperature long time (LTLT), or with a retort. The control samples were treated with 10% calcium chloride to stop enzymatic activity in the juice. Sauce was made from juice and the tomato products were analyzed for volatiles, color, viscosity, and by sensory. Cold break juice made with peel contained higher levels of some lipoxygenase-, carotenoid-, and amino acid-derived volatiles, than the juice made without peel. Because of the lack of enzyme activity, hot break juices had lower levels of these volatiles and there was no significant difference between hot break juices made with and without peel. CaCl2 -treated and HTST juice had higher levels of most of the volatiles than LTLT, including the lipoxygenase-derived volatiles. The presence of peel produced a significant decrease in the viscosity of the cold break juice and sauce. There was no significant difference in the hue angle, total soluble solids, pH, titratable acidity, and vitamin C for most of the treatments. The texture, flavor, and overall liking of cold break juice made without peel were preferred over cold break juice made with peel whereas the color was less preferred. Between the sauces no significant differences in preference were obtained.

  8. An Improved Lattice Kinetic Scheme for Incompressible Viscous Fluid Flows

    NASA Astrophysics Data System (ADS)

    Suzuki, Kosuke; Inamuro, Takaji

    2014-01-01

    The lattice Boltzmann method (LBM) is an explicit numerical scheme for the incompressible Navier-Stokes equations (INSE) without integrating the Poisson equation for the pressure. In spite of its merit, the LBM has some drawbacks in accuracy. First, we review drawbacks for three numerical methods based on the LBM. The three methods are the LBM with the Bhatnagar-Gross-Krook model (LBGK), the lattice kinetic scheme (LKS) and the link-wise artificial compressibility method (LWACM). Second, in order to remedy the drawbacks, we propose an improved LKS. The present method incorporates (i) the scheme used in the LWACM for determining the kinematic viscosity, (ii) an iterative calculation of the pressure and (iii) a semi-implicit algorithm, while preserving the simplicity of the algorithm of the original LKS. Finally, in simulations of test problems, we find that the improved LKS eliminates the drawbacks and gives more accurate and stable results than LBGK, LKS and LWACM.

  9. Using LEAN to improve a segment of emergency department flow.

    PubMed

    Vose, Courtney; Reichard, Christine; Pool, Susan; Snyder, Megan; Burmeister, David

    2014-11-01

    Emergency department (ED) overcrowding is an organizational concern. This article describes how Toyota LEAN methods were used as a performance improvement framework to address ED overcrowding. This initiative also impacted "bolus of patients" or "batching" concerns, which occur when inpatient units receive an influx of patients from EDs and other areas at the same time. In addition to decreased incidence of overcrowding, the organization realized increased interprofessional collaboration.

  10. Numerical and Experimental Studies of the Natural Convection Flow Within a Horizontal Cylinder Subjected to a Uniformly Cold Wall Boundary Condition. Ph.D. Thesis - Va. Poly. Inst. and State Univ.

    NASA Technical Reports Server (NTRS)

    Stewart, R. B.

    1972-01-01

    Numberical solutions are obtained for the quasi-compressible Navier-Stokes equations governing the time dependent natural convection flow within a horizontal cylinder. The early time flow development and wall heat transfer is obtained after imposing a uniformly cold wall boundary condition on the cylinder. Solutions are also obtained for the case of a time varying cold wall boundary condition. Windware explicit differ-encing is used for the numerical solutions. The viscous truncation error associated with this scheme is controlled so that first order accuracy is maintained in time and space. The results encompass a range of Grashof numbers from 8.34 times 10,000 to 7 times 10 to the 7th power which is within the laminar flow regime for gravitationally driven fluid flows. Experiments within a small scale instrumented horizontal cylinder revealed the time development of the temperature distribution across the boundary layer and also the decay of wall heat transfer with time.

  11. Improving emergency department flow through Rapid Medical Evaluation unit

    PubMed Central

    Chartier, Lucas; Josephson, Timothy; Bates, Kathy; Kuipers, Meredith

    2015-01-01

    The Toronto Western Hospital is an academic hospital in Toronto, Canada, with an annual Emergency Department (ED) volume of 64,000 patients. Despite increases in patient volumes of almost six percent per annum over the last decade, there have been no commensurate increases in resources, infrastructure, and staffing. This has led to substantial increase in patient wait times, most specifically for those patients with lower acuity presentations. Despite requiring only minimal care, these patients contribute disproportionately to ED congestion, which can adversely impact resource utilization and quality of care for all patients. We undertook a retrospective evaluation of a quality improvement initiative aimed at improving wait times experienced by patients with lower acuity presentations. A rapid improvement event was organized by frontline workers to rapidly overhaul processes of care, leading to the creation of the Rapid Medical Evaluation (RME) unit – a new pathway of care for patients with lower acuity presentations. The RME unit was designed by re-purposing existing resources and re-assigning one physician and one nurse towards the specific care of these patients. We evaluated the performance of the RME unit through measurement of physician initial assessment (PIA) times and total length of stay (LOS) times for multiple groups of patients assigned to various ED care pathways, during three periods lasting three months each. Weekly measurements of mean and 90th percentile of PIA and LOS times showed special cause variation in all targeted patient groups. Of note, the patients seen in the RME unit saw their median PIA and LOS times decrease from 98min to 70min and from 165min to 130min, respectively, from baseline. Despite ever-growing numbers of patient visits, wait times for all patients with lower acuity presentations remained low, and wait times of patients with higher acuity presentations assigned to other ED care pathways were not adversely affected. By

  12. Improving emergency department flow through Rapid Medical Evaluation unit.

    PubMed

    Chartier, Lucas; Josephson, Timothy; Bates, Kathy; Kuipers, Meredith

    2015-01-01

    The Toronto Western Hospital is an academic hospital in Toronto, Canada, with an annual Emergency Department (ED) volume of 64,000 patients. Despite increases in patient volumes of almost six percent per annum over the last decade, there have been no commensurate increases in resources, infrastructure, and staffing. This has led to substantial increase in patient wait times, most specifically for those patients with lower acuity presentations. Despite requiring only minimal care, these patients contribute disproportionately to ED congestion, which can adversely impact resource utilization and quality of care for all patients. We undertook a retrospective evaluation of a quality improvement initiative aimed at improving wait times experienced by patients with lower acuity presentations. A rapid improvement event was organized by frontline workers to rapidly overhaul processes of care, leading to the creation of the Rapid Medical Evaluation (RME) unit - a new pathway of care for patients with lower acuity presentations. The RME unit was designed by re-purposing existing resources and re-assigning one physician and one nurse towards the specific care of these patients. We evaluated the performance of the RME unit through measurement of physician initial assessment (PIA) times and total length of stay (LOS) times for multiple groups of patients assigned to various ED care pathways, during three periods lasting three months each. Weekly measurements of mean and 90th percentile of PIA and LOS times showed special cause variation in all targeted patient groups. Of note, the patients seen in the RME unit saw their median PIA and LOS times decrease from 98min to 70min and from 165min to 130min, respectively, from baseline. Despite ever-growing numbers of patient visits, wait times for all patients with lower acuity presentations remained low, and wait times of patients with higher acuity presentations assigned to other ED care pathways were not adversely affected. By

  13. Performance of Improved High-Order Filter Schemes for Turbulent Flows with Shocks

    NASA Technical Reports Server (NTRS)

    Kotov, Dmitry Vladimirovich; Yee, Helen M C.

    2013-01-01

    The performance of the filter scheme with improved dissipation control ? has been demonstrated for different flow types. The scheme with local ? is shown to obtain more accurate results than its counterparts with global or constant ?. At the same time no additional tuning is needed to achieve high accuracy of the method when using the local ? technique. However, further improvement of the method might be needed for even more complex and/or extreme flows.

  14. Shear flow control of cold and heated rectangular jets by mechanical tabs. Volume 1: Results and discussion

    NASA Technical Reports Server (NTRS)

    Brown, W. H.; Ahuja, K. K.

    1989-01-01

    The effects of mechanical protrusions on the jet mixing characteristics of rectangular nozzles for heated and unheated subsonic and supersonic jet plumes were studied. The characteristics of a rectangular nozzle of aspect ratio 4 without the mechanical protrusions were first investigated. Intrusive probes were used to make the flow measurements. Possible errors introduced by intrusive probes in making shear flow measurements were also examined. Several scaled sizes of mechanical tabs were then tested, configured around the perimeter of the rectangular jet. Both the number and the location of the tabs were varied. From this, the best configuration was selected. The conclusions derived were: (1) intrusive probes can produce significant errors in the measurements of the velocity of jets if they are large in diameter and penetrate beyond the jet center; (2) rectangular jets without tabs, compared to circular jets of the same exit area, provide faster jet mixing; and (3) further mixing enhancement is possible by using mechanical tabs.

  15. Experimental cold-flow evaluation of a ram air cooled plug nozzle concept for afterburning turbojet engines

    NASA Technical Reports Server (NTRS)

    Straight, D. M.; Harrington, D. E.

    1973-01-01

    A concept for plug nozzles cooled by inlet ram air is presented. Experimental data obtained with a small scale model, 21.59-cm (8.5-in.) diameter, in a static altitude facility demonstrated high thrust performance and excellent pumping characteristics. Tests were made at nozzle pressure ratios simulating supersonic cruise and takeoff conditions. Effect of plug size, outer shroud length, and varying amounts of secondary flow were investigated.

  16. Improved flow characteristics of bauxite by treatment with a bauxite handling aid

    SciTech Connect

    Cardounel, C.; O`Brien, K.

    1996-10-01

    Sherwin Plant bauxite handling facilities are capable of processing relatively free flowing dry bauxites. The processing of wet bauxite through these facilities was challenging and required the use of backhoes and bulldozers. The use of a bauxite handling aid to enhance flow properties of wet bauxite was investigated in the laboratory and subsequently tested in the plant. A significant improvement in flow characteristics was achieved. The bauxite became free flowing, eliminating the need for backhoes and bulldozers to reclaim the bauxite. This paper relates how laboratory testing led to successful plant application of the bauxite handling aid.

  17. Improved numerical methods for turbulent viscous flows aerothermal modeling program, phase 2

    NASA Technical Reports Server (NTRS)

    Karki, K. C.; Patankar, S. V.; Runchal, A. K.; Mongia, H. C.

    1988-01-01

    The details of a study to develop accurate and efficient numerical schemes to predict complex flows are described. In this program, several discretization schemes were evaluated using simple test cases. This assessment led to the selection of three schemes for an in-depth evaluation based on two-dimensional flows. The scheme with the superior overall performance was incorporated in a computer program for three-dimensional flows. To improve the computational efficiency, the selected discretization scheme was combined with a direct solution approach in which the fluid flow equations are solved simultaneously rather than sequentially.

  18. Improved lattice Boltzmann model for multi-component diffusion flow with large pressure difference

    NASA Astrophysics Data System (ADS)

    Liu, Fu-Min; Wang, An-Lin; Qiu, Ruo-Fan; Jiang, Tao

    2016-05-01

    The pseudopotential lattice Boltzmann model has been widely used to solve multi-phase and multi-component flow problems. However, original pseudopotential model cannot be used in simulating diffusion flow with large pressure difference because of its limitation. In this paper, we incorporate pseudopotential model with a new form of effective mass to solve this problem based on the relationship between pressure difference and effective mass. The improved model is verified through Laplace’s law and binary immiscible Poiseuille flow. By simulating pipeline binary diffusion flow and two-inlet binary cavity jet flow, we show that the improved model can achieve larger pressure difference than pseudopotential model with traditional effective mass forms.

  19. Improved Soft Abrasive Flow Finishing Method Based on Turbulent Kinetic Energy Enhancing

    NASA Astrophysics Data System (ADS)

    LI, Jun; JI, Shiming; TAN, Dapeng

    2017-03-01

    Soft abrasive flow(SAF) finishing can process the irregular geometric surfaces, but with the matter of low processing efficiency. To address the issue, an improved SAF finishing method based on turbulent kinetic energy enhancing is proposed. A constrained flow passage with serration cross-section is constructed to increase the turbulence intensity. Taking the constrained flow passage as the objective, a two-phase fluid dynamic model is set up by using particle trajectory model and standard k-ɛ turbulence model, and the flow field characteristics of the flow passage are acquired. The numerical results show that the serration flow passage can enhance the turbulence intensity, uniform the particles distribution, and increase the particle concentration near the bottom wall. The observation results by particle image velocimetry(PIV) show that the internal vortex structures are formed in flow passage, and the abrasive flow takes on turbulence concentrating phenomenon in near-wall region. The finishing experiments prove that the proposed method can obtain better surface uniformity, and the processing efficiency can be improved more 35%. This research provides an abrasive flow modeling method to reveal the particle motion regulars, and can offer references to the technical optimization of fluid-based precision processing.

  20. Acute cold stress improved the transcription of pro-inflammatory cytokines of Chinese soft-shelled turtle against Aeromonas hydrophila.

    PubMed

    Zhang, Zuobing; Chen, Bojian; Yuan, Lin; Niu, Cuijuan

    2015-03-01

    Chinese soft-shelled turtle, Pelodiscus sinensis, is widely cultured in East and Southeast Asian countries. It frequently encounters the stress of abrupt temperature changes, which leads to mass death in most cases. However, the mechanism underlying the stress-elicited death remains unknown. We have suspected that the stress impaired the immune function of Chinese soft-shelled turtle, which could result in the mass death, as we noticed that there was a clinical syndrome of infection in dead turtles. To test our hypothesis, we first performed bioinformatic annotation of several pro-inflammatory molecules (IL-1β, TNFα, IL-6, IL-12β) of Chinese soft-shelled turtle. Then, we treated the turtles in six groups, injected with Aeromonas hydrophila before acute cold stress (25 °C) and controls, after acute cold stress (15 °C) and controls as well as after the temperature was restored to 25 °C and controls, respectively. Subsequently, real-time PCR for several pro-inflammatory cytokines (IL-1β, TNFα, IL-6, IL-12β, IL-8 and IFNγ) was performed to assess the turtle immune function in spleen and intestine, 24 hours after the injection. We found that the mRNA expression levels of the immune molecules were all enhanced after acute cold stress. This change disappeared when the temperature was restored back to 25 °C. Our results suggest that abrupt temperature drop did not suppress the immune function of Chinese soft-shelled turtle in response to germ challenge after abrupt temperature drop. In contrast, it may even increase the expression of various cytokines at least, within a short time after acute cold stress.

  1. An improved Peltier effect-based instrument for critical temperature threshold measurement in cold- and heat-induced urticaria.

    PubMed

    Magerl, M; Abajian, M; Krause, K; Altrichter, S; Siebenhaar, F; Church, M K

    2015-10-01

    Cold- and heat-induced urticaria are chronic physical urticaria conditions in which wheals, angioedema or both are evoked by skin exposure to cold and heat respectively. The diagnostic work up of both conditions should include skin provocation tests and accurate determination of critical temperature thresholds (CTT) for producing symptoms in order to be able to predict the potential risk that each individual patient faces and how this may be ameliorated by therapy. To develop and validate TempTest(®) 4, a simple and relatively inexpensive instrument for the accurate determination of CTT which may be used in clinical practice. TempTest(®) 4 has a single 2 mm wide 350 mm U-shaped Peltier element generating a temperature gradient from 4 °C to 44 °C along its length. Using a clear plastic guide placed over the skin after provocation, CTT values may be determined with an accuracy of ±1 °C. Here, TempTest(®) 4 was compared with its much more expensive predecessor, TempTest(®) 3, in inducing wheals in 30 cold urticaria patients. Both TempTest(®) 4 and TempTest(®) 3 induced wheals in all 30 patients between 8 ° and 28 °C. There was a highly significant (P < 0.0001) correlation between the instruments in the CTT values in individual patients. The TempTest(®) 4 is a simple, easy to use, licensed, commercially available and affordable instrument for the determination of CTTs in both cold- and heat-induced urticaria. © 2014 European Academy of Dermatology and Venereology.

  2. High Sensitivity Carbon Nanotubes Flow-Rate Sensors and Their Performance Improvement by Coating

    PubMed Central

    Yang, Xing; Zhou, Zhaoying; Wang, Dingqu; Liu, Xiaoli

    2010-01-01

    A new type of hot-wire flow-rate sensor (HWFS) with a sensing element made of a macro-sized carbon nanotube (CNT) strand is presented in this study. An effective way to improve repeatability of the CNT flow-rate sensor by coating a layer of Al2O3 on the CNT surface is proposed. Experimental results show that due to the large surface-to-volume ratio and thin coated Al2O3 layer, the CNT flow-rate sensor has higher sensitivity and faster response than a conventional platinum (Pt) HWFS. It is also demonstrated that the covered CNT flow-rate sensor has better repeatability than its bare counterpart due to insulation from the surrounding environment. The proposed CNT flow-rate sensor shows application potential for high-sensitivity measurement of flow rate. PMID:22399913

  3. Viewpoint oscillation improves the perception of distance travelled based on optic flow.

    PubMed

    Bossard, Martin; Goulon, Cédric; Mestre, Daniel R

    2016-12-01

    When static observers are presented with a visual simulation of forward self-motion, they generally misestimate distance travelled relative to a previously seen distant target: It has been suggested that this finding can be accounted for by a "leaky path integration" model. In the present study, using a similar experimental procedure, this result was confirmed. It was also established that combining the translational optical flow with simulated head oscillations (similar to those during natural walking) improved the subjects' perception of the distance travelled in comparison with a purely translational flow. This improvement may be attributable to the fact that an optic flow pattern resembling that associated with walking enhances the path integration process. In a subsequent experiment, we investigated whether it was the biological or the rhythmical characteristics of the simulation that enhanced the subjects' estimates of the distance travelled. The results obtained confirm that adding rhythmic components to the optic flow pattern improved the accuracy of subjects' perception of the distance travelled. However, no significant differences between biological and rhythmical oscillations were detected. These results relate to recent studies on the effects of smooth and jittering optic flows on vection onset and strength. One possible conclusion is that oscillations may increase the global retinal motion and thus improve the vection and path integration processes. Another possibility is that the nonmonotonous pattern of retinal motion induced by oscillatory inputs may maintain optimum sensitivity to the optic flow over time and thus improve the accuracy of subjects' perception of the distance travelled.

  4. Improvement of hemodynamic performance using novel helical flow vena cava filter design

    PubMed Central

    Chen, Ying; Zhang, Peng; Deng, Xiaoyan; Fan, Yubo; Xing, Yubin; Xing, Ning

    2017-01-01

    We propose a vena cava filter in which helical flow is created in the filter’s working zone to minimize filter blockage by trapped clots and facilitate the lysis of trapped clots. To validate this new design, we compared five helical flow inducers with different thread pitches in terms of blood flow patterns in the filter. The vena cava was reconstructed based on computed tomography images. Both the numerical simulation and in vitro experiment revealed that the helical flow inducer can effectively create a helical flow in the vessel, thereby subduing the filter structure’s adverse disruption to blood flow, and increasing flow-induced shear stress in the filter center. In addition, the smaller thread pitch helical flow inducer reduced the oscillating shear index and relative residence time on the vessel wall. Moreover, we observed that the helical flow inducer in the vena cava could induce flow rotation both in clockwise and counterclockwise directions. In conclusion, the new design of the filter with the smaller thread pitch inducer is advantageous over the traditional filter in terms of improving local hemodynamics, which may reduce thrombosis build-up after deployment. PMID:28112186

  5. Electronic Equipment Cold Plates

    DTIC Science & Technology

    1976-04-01

    equations for such a flow regiae. For laainar flow and Moderate teaperature differwwe« between the well «nd coolant, a aodifled Sieder -Tate...con- figuration. The heat-transfer coefficients, therefore, were determined by using both the Sieder -Tate and McAdams equations and the coaputed...values used In the analytical predictions. As with th* previous cold Plates, the Sieder -Tate equation gave too low of values for the heat- transfer

  6. Experimental study on improvement effect of guide wall to water flow in bend of spillway chute.

    PubMed

    Zhang, Qinghua; Diao, Yanfang; Zhai, Xingtao; Li, Shuning

    2016-01-01

    In order to improve water flow in a bend of a spillway chute using a guide wall, modeling experiments with or without a guide wall under conditions of three different bend axial radii, three chute bottom slopes and three flow rates were carried out in this study. Two indexes were calculated, which are the improved water surface uniformity and the reduced rate of water surface difference in concave and convex banks of the cross-section. The results show that: (1) setting a guide wall in a bend can improve water flow in the bend because it increased the water surface uniformity of the cross-section and reduced the water surface difference in the concave and convex banks; (2) the smaller the bend axial radius, the better the water surface improvement effect will be using a guide wall; (3) the steeper the bottom slope, the more cross-sections with less water surface difference; and (4) flow rates have a great influence on water surface improvement in the bend, and the guide wall can improve water flow obviously when the water depth in the starting section of the bend is lower than the height of the guide wall. This study has important implications in engineering design of guide walls.

  7. Improving Flow Response of a Variable-rate Aerial Application System by Interactive Refinement

    USDA-ARS?s Scientific Manuscript database

    Experiments were conducted to evaluate response of a variable-rate aerial application controller to changing flow rates and to improve its response at correspondingly varying system pressures. System improvements have been made by refinement of the control algorithms over time in collaboration with ...

  8. Sub-piexl methods for improving vector quality in echo PIV flow, imaging technology.

    PubMed

    Niu, Lili; Wang, Jing; Qian, Ming; Zheng, Hairong

    2009-01-01

    Developments of many cardiovascular problems have been shown to have a close relationship with arterial flow conditions. An ultrasound-based particle image velocimetry technique(Echo PIV) was recently developed to measure multi-component velocity vectors and local shear rates in arteries and opaque fluid flows by identifying and tracking flow tracers (ultrasound contrast microbubbles) within these flow fields. To improve the measurement accuracy, sub-pixel calculation method was adopted in this paper to maximize the ultrasound RF signal and B mode image correlation accuracy and increase the image spatial resolution. This algorithm is employed in processing both computer-generated particle image patterns and the B-mode images of microbubbles in rotating flows obtained by a high frame rate (up to 1000 frames per second) ultrasound imaging system. The results show the correlation of particle patterns and individual flow vector quality are improved and the overall flow mappings are also improved significantly. This would help the Echo PIV system to provide better multi-component velocity accuracy.

  9. Ultrasonic particle image velocimetry for improved flow gradient imaging: algorithms, methodology and validation.

    PubMed

    Niu, Lili; Qian, Ming; Wan, Kun; Yu, Wentao; Jin, Qiaofeng; Ling, Tao; Gao, Shen; Zheng, Hairong

    2010-04-07

    This paper presents a new algorithm for ultrasonic particle image velocimetry (Echo PIV) for improving the flow velocity measurement accuracy and efficiency in regions with high velocity gradients. The conventional Echo PIV algorithm has been modified by incorporating a multiple iterative algorithm, sub-pixel method, filter and interpolation method, and spurious vector elimination algorithm. The new algorithms' performance is assessed by analyzing simulated images with known displacements, and ultrasonic B-mode images of in vitro laminar pipe flow, rotational flow and in vivo rat carotid arterial flow. Results of the simulated images show that the new algorithm produces much smaller bias from the known displacements. For laminar flow, the new algorithm results in 1.1% deviation from the analytically derived value, and 8.8% for the conventional algorithm. The vector quality evaluation for the rotational flow imaging shows that the new algorithm produces better velocity vectors. For in vivo rat carotid arterial flow imaging, the results from the new algorithm deviate 6.6% from the Doppler-measured peak velocities averagely compared to 15% of that from the conventional algorithm. The new Echo PIV algorithm is able to effectively improve the measurement accuracy in imaging flow fields with high velocity gradients.

  10. Engineered particles demonstrate improved flow properties at elevated drug loadings for direct compression manufacturing.

    PubMed

    Trementozzi, Andrea N; Leung, Cheuk-Yui; Osei-Yeboah, Frederick; Irdam, Erwin; Lin, Yiqing; MacPhee, J Michael; Boulas, Pierre; Karki, Shyam B; Zawaneh, Peter N

    2017-03-08

    Optimizing powder flow and compaction properties are critical for ensuring a robust tablet manufacturing process. The impact of flow and compaction properties of the active pharmaceutical ingredient (API) becomes progressively significant for higher drug load formulations, and for scaling up manufacturing processes. This study demonstrated that flow properties of a powder blend can be improved through API particle engineering, without critically impacting blend tabletability at elevated drug loadings. In studying a jet milled API (D50=24μm) and particle engineered wet milled API (D50=70μm and 90μm), flow functions of all API lots were similarly poor despite the vast difference in average particle size (ffc<4). This finding strays from the common notion that powder flow properties are directly correlated to particle size distribution. Upon adding excipients, however, clear trends in flow functions based on API particle size were observed. Wet milled API blends had a much improved flow function (ffc>10) compared with the jet milled API blends. Investigation of the compaction properties of both wet and jet milled powder blends also revealed that both jet and wet milled material produced robust tablets at the drug loadings used. The ability to practically demonstrate this uncommon observation that similarly poor flowing APIs can lead to a marked difference upon blending is important for pharmaceutical development. It is especially important in early phase development during API selection, and is advantageous particularly when material-sparing techniques are utilized.

  11. Temporal characteristics of electrostatic surface waves in a cold complex plasma containing collision-dominated ion flow

    NASA Astrophysics Data System (ADS)

    Lee, Myoung-Jae; Jung, Young-Dae

    2017-03-01

    The influence of electron-ion collision frequency and dust charge on the growth rate of two-stream instability of the electrostatic surface wave propagating at the interface of semi-infinite complex plasma whose constituents are electrons, negatively charged dust, and streaming ions. It is found that the surface wave can be unstable if the multiplication of wave number and ion flow velocity is greater than the total plasma frequency of electrons and dusts. The analytical solution of the growth rate is derived as a function of collision frequency, dust charge, and ion-to-electron density ratio. It is found that the growth rate is inversely proportional to the collision rate, but it is enhanced as the number of electrons residing on the dust grain surface is increased. The growth rate of surface wave is compared to that of the bulk wave.

  12. Rational Engineering of a Cold-Adapted α-Amylase from the Antarctic Ciliate Euplotes focardii for Simultaneous Improvement of Thermostability and Catalytic Activity

    PubMed Central

    Yang, Guang; Yao, Hua; Mozzicafreddo, Matteo; Ballarini, Patrizia; Pucciarelli, Sandra

    2017-01-01

    ABSTRACT The α-amylases are endo-acting enzymes that hydrolyze starch by randomly cleaving the 1,4-α-d-glucosidic linkages between the adjacent glucose units in a linear amylose chain. They have significant advantages in a wide range of applications, particularly in the food industry. The eukaryotic α-amylase isolated from the Antarctic ciliated protozoon Euplotes focardii (EfAmy) is an alkaline enzyme, different from most of the α-amylases characterized so far. Furthermore, EfAmy has the characteristics of a psychrophilic α-amylase, such as the highest hydrolytic activity at a low temperature and high thermolability, which is the major drawback of cold-active enzymes in industrial applications. In this work, we applied site-directed mutagenesis combined with rational design to generate a cold-active EfAmy with improved thermostability and catalytic efficiency at low temperatures. We engineered two EfAmy mutants. In one mutant, we introduced Pro residues on the A and B domains in surface loops. In the second mutant, we changed Val residues to Thr close to the catalytic site. The aim of these substitutions was to rigidify the molecular structure of the enzyme. Furthermore, we also analyzed mutants containing these combined substitutions. Biochemical enzymatic assays of engineered versions of EfAmy revealed that the combination of mutations at the surface loops increased the thermostability and catalytic efficiency of the enzyme. The possible mechanisms responsible for the changes in the biochemical properties are discussed by analyzing the three-dimensional structural model. IMPORTANCE Cold-adapted enzymes have high specific activity at low and moderate temperatures, a property that can be extremely useful in various applications as it implies a reduction in energy consumption during the catalyzed reaction. However, the concurrent high thermolability of cold-adapted enzymes often limits their applications in industrial processes. The α-amylase from the

  13. Cold injuries.

    PubMed

    Kruse, R J

    1995-01-01

    There are two categories of cold injury. The first is hypothermia, which is a systemic injury to cold, and the second is frostbite, which is a local injury. Throughout history, entire armies, from George Washington to the Germans on the Russian Front in World War II, have fallen prey to prolonged cold exposure. Cold injury is common and can occur in all seasons if ambient temperature is lower than the core body temperature. In the 1985 Boston Marathon, even though it was 76 degrees and sunny, there were 75 runners treated for hypothermia. In general, humans adapt poorly to cold exposure. Children are at particular risk because of their relatively greater surface area/body mass ratio, causing them to cool even more rapidly than adults. Because of this, the human's best defense against cold injury is to limit his/her exposure to cold and to dress appropriately. If cold injury has occurred and is mild, often simple passive rewarming such as dry blankets and a warm room are sufficient treatment.

  14. Rapid cold hardening improves recovery of ion homeostasis and chill coma recovery time in the migratory locust, Locusta migratoria.

    PubMed

    Findsen, Anders; Andersen, Jonas Lembcke; Calderon, Sofia; Overgaard, Johannes

    2013-05-01

    Chill tolerance of insects is defined as the ability to tolerate low temperature under circumstances not involving freezing of intracellular or extracellular fluids. For many insects chill tolerance is crucial for their ability to persist in cold environments and mounting evidence indicates that chill tolerance is associated with the ability to maintain ion and water homeostasis, thereby ensuring muscular function and preventing chill injury at low temperature. The present study describes the relationship between muscle and haemolymph ion homeostasis and time to regain posture following cold shock (CS, 2 h at -4°C) in the chill-susceptible locust Locusta migratoria. This relationship was examined in animals with and without a prior rapid cold-hardening treatment (RCH, 2 h at 0°C) to investigate the physiological underpinnings of RCH. CS elicited a doubling of haemolymph [K(+)] and this disturbance was greater in locusts pre-exposed to RCH. Recovery of ion homeostasis was, however, markedly faster in RCH-treated animals, which correlated well with whole-organism performance as hardened individuals regained posture faster than non-hardened individuals following CS. The present study indicates that loss and recovery of muscular function are associated with the resting membrane potential of excitable membranes as attested by the changes in the equilibrium potential for K(+) (EK) following CS. Both hardened and non-hardened animals regained movement once K(+) homeostasis had recovered to a fixed level (EK≈-41 mV). RCH is therefore not associated with altered sensitivity to ion disturbance but instead is correlated to a faster recovery of haemolymph [K(+)].

  15. Enhanced external counterpulsation improves peripheral resistance artery blood flow in patients with coronary artery disease.

    PubMed

    Avery, Joseph C; Beck, Darren T; Casey, Darren P; Sardina, Paloma D; Braith, Randy W

    2014-03-01

    Enhanced external counterpulsation (EECP) increases coronary artery perfusion and improves endothelium-dependent vasodilation in peripheral muscular conduit arteries. It is unknown whether vasodilatory capacity is improved in the peripheral resistance vasculature. Here we provide novel evidence from the first randomized, sham-controlled study that EECP increases peak limb blood flow and improves endothelium-dependent vasodilation in both calf and forearm resistance arteries in patients with coronary artery disease.

  16. Improvements in sparse matrix/vector technique applications for on-line load flow calculation

    SciTech Connect

    Ristanovic, P.; Bjelogrlic, M.; Babic, B.S.

    1989-02-01

    Sparsity technique is applied to a wide range of problems in power systems analysis. In this paper the authors propose several analytical and computational improvements in sparsity applications. The new partial matrix refactorization method and ordering algorithm are presented. The proposed method is very efficient when applied to various kinds of programs, such as: on-line load flow, optimal power flow and steady-state security analysis. The proposed methodology is applied in a fast decoupled load flow program which include the treatment of tap violations on under-load tap changing (ULTC) transformers and reactive power generation on PV buses. Effects of proposed improvements are well tested and documented on the three networks: 118 bus IEEE test network and two utility networks with 209 and 519 buses, respectively. Keywords: sparsity technique, load flow analysis, security analysis.

  17. Improved prediction of disturbed flow via hemodynamically-inspired geometric variables.

    PubMed

    Bijari, Payam B; Antiga, Luca; Gallo, Diego; Wasserman, Bruce A; Steinman, David A

    2012-06-01

    Arterial geometry has long been considered as a pragmatic alternative for inferring arterial flow disturbances, and their impact on the natural history and treatment of vascular diseases. Traditionally, definition of geometric variables is based on convenient shape descriptors, with only superficial consideration of their influence on flow and wall shear stress patterns. In the present study we demonstrate that a more studied consideration of the actual (cf. nominal) local hemodynamics can lead to substantial improvements in the prediction of disturbed flow by geometry. Starting from a well-characterized computational fluid dynamics (CFD) dataset of 50 normal carotid bifurcations, we observed that disturbed flow tended to be confined proximal to the flow divider, whereas geometric variables previously shown to be significant predictors of disturbed flow included features distal to the flow divider in their definitions. Flaring of the bifurcation leading to flow separation was redefined as the maximum relative expansion of the common carotid artery (CCA), proximal to the flow divider. The beneficial effect of primary curvature on flow inertia, via suppression of flow separation, was characterized by the in-plane tortuosity of CCA as it enters the flare region. Multiple linear regressions of these redefined geometric variables against various metrics of disturbed flow revealed R(2) values approaching 0.6, better than the roughly 0.3 achieved using the conventional shape-based variables, while maintaining their demonstrated real-world reproducibility. Such a hemodynamically-inspired approach to the definition of geometric variables may reap benefits for other applications where geometry is used as a surrogate marker of local hemodynamics.

  18. Design and analysis of Air flow duct for improving the thermal performance of disc brake rotor

    NASA Astrophysics Data System (ADS)

    Raja, T.; Mathiselvan, G.; Sreenivasulureddy, M.; Goldwin Xavier, X.

    2017-05-01

    safety in automotive engineering has been considered as a number one priority in development of new vehicle. A brake system is one of the most critical systems in the vehicle, without which the vehicle will put a passenger in an unsafe position. Temperature distribution on disc rotor brake and the performance brake of disc rotor is influenced by the air flow around the disc rotor. In this paper, the effect of air flow over the disc rotor is analyzed using the CFD software. The air flow over the disc rotor is increased by using a duct to supply more air flow over the disc rotor. The duct is designed to supply more air to the rotor surface and it can be placed in front of the vehicle for better performance. Increasing the air flow around the rotor will maximize the heat convection from the rotor surface. The rotor life and the performance can be improved.

  19. Improved radiation dose efficiency in solution SAXS using a sheath flow sample environment

    PubMed Central

    Kirby, Nigel; Cowieson, Nathan; Hawley, Adrian M.; Mudie, Stephen T.; McGillivray, Duncan J.; Kusel, Michael; Samardzic-Boban, Vesna; Ryan, Timothy M.

    2016-01-01

    Radiation damage is a major limitation to synchrotron small-angle X-ray scattering analysis of biomacromolecules. Flowing the sample during exposure helps to reduce the problem, but its effectiveness in the laminar-flow regime is limited by slow flow velocity at the walls of sample cells. To overcome this limitation, the coflow method was developed, where the sample flows through the centre of its cell surrounded by a flow of matched buffer. The method permits an order-of-magnitude increase of X-ray incident flux before sample damage, improves measurement statistics and maintains low sample concentration limits. The method also efficiently handles sample volumes of a few microlitres, can increase sample throughput, is intrinsically resistant to capillary fouling by sample and is suited to static samples and size-exclusion chromatography applications. The method unlocks further potential of third-generation synchrotron beamlines to facilitate new and challenging applications in solution scattering. PMID:27917826

  20. Improved radiation dose efficiency in solution SAXS using a sheath flow sample environment.

    PubMed

    Kirby, Nigel; Cowieson, Nathan; Hawley, Adrian M; Mudie, Stephen T; McGillivray, Duncan J; Kusel, Michael; Samardzic-Boban, Vesna; Ryan, Timothy M

    2016-12-01

    Radiation damage is a major limitation to synchrotron small-angle X-ray scattering analysis of biomacromolecules. Flowing the sample during exposure helps to reduce the problem, but its effectiveness in the laminar-flow regime is limited by slow flow velocity at the walls of sample cells. To overcome this limitation, the coflow method was developed, where the sample flows through the centre of its cell surrounded by a flow of matched buffer. The method permits an order-of-magnitude increase of X-ray incident flux before sample damage, improves measurement statistics and maintains low sample concentration limits. The method also efficiently handles sample volumes of a few microlitres, can increase sample throughput, is intrinsically resistant to capillary fouling by sample and is suited to static samples and size-exclusion chromatography applications. The method unlocks further potential of third-generation synchrotron beamlines to facilitate new and challenging applications in solution scattering.

  1. Modification and Improvement of Software for Modeling Multidimensional Reacting Fuel Flows

    DTIC Science & Technology

    1989-07-01

    aQ IC FILE COPY WRDC-TR-89-2056 MODIFICATION AND IMPROVEMENT OF SOFTWARE FOR MODELING MULTIDIMENSIONAL REACTING FUEL FLOWS Dr. David E. Keyes Mr...Modeling Multidimensional Reacting Fuel Flows 12. PERSONAL AUITHOR(S Dr. David Keyes , Mr. Dennis Philbin, Dr. Mitchell Smoke I I& TYPt Of IMPORT 113b. TIME...al. [15], and Keyes and Smooke [16)). We assume that the fuel and the oxidizer obey a single overall irreversible reaction of the type Fuel (F

  2. Smart low flow signature metrics for an improved overall performance evaluation of hydrological models

    NASA Astrophysics Data System (ADS)

    Pfannerstill, Matthias; Guse, Björn; Fohrer, Nicola

    2014-03-01

    Hydrological models have to be calibrated accurately to provide reasonable model results. For a concise model evaluation, the different phases of the hydrograph have to be considered in multi-metric frameworks with appropriate performance metrics. Low and high flows need to be reproduced simultaneously without neglecting the other phases of the hydrograph. In this paper, we highlight the relevance of very low and low flows with separate performance metrics. We present a multi-metric evaluation framework to identify calibration runs, which represent the different phases of the hydrograph precisely. A stepwise evaluation was done with commonly used statistical performance metrics (Nash-Sutcliffe, percent bias) and signature metrics, which are based on the flow duration curve (FDC). In order to consider a fairly balanced evaluation between high and low flow phases, we divided the flow duration curve into segments of high, medium and low flow phases, and additionally into very high and very low flow phases. The model performance in these segments was evaluated separately with the root mean square error (RMSE). Our results show that this evaluation method leads to an improved selection of good calibration runs to enhance the overall model performance by the refined segmentation of FDC. By combining performance metrics for high flow conditions with low flow conditions, this study demonstrates the challenge of calibrating a model with a satisfactory performance in high and low phases simultaneously. Consequently, we conclude that an additional performance metric for very low flows should be included in model analyzes to improve the overall performance in all phases of the hydrograph.

  3. Improving the estimation of flow speed for laser speckle imaging with single exposure time.

    PubMed

    Wang, Yang; Wen, Dong; Chen, Xiao; Huang, Qin; Chen, Ming; Lu, Jinling; Li, Pengcheng

    2017-01-01

    Laser speckle contrast imaging is a full-field imaging technique for measuring blood flow by mapping the speckle contrast with high spatial and temporal resolution. However, the statically scattered light from stationary tissues seriously degrades the accuracy of flow speed estimation. In this Letter, we present a simple calibration approach to calculate the proportions of dynamically scattered light and correct the effect of static scattering with single exposure time. Both the phantom and animal experimental results suggest that this calibration approach has the ability to improve the estimation of the relative blood flow in the presence of static scattering.

  4. Improving flow properties of ibuprofen by fluidized bed particle thin-coating.

    PubMed

    Ehlers, Henrik; Räikkönen, Heikki; Antikainen, Osmo; Heinämäki, Jyrki; Yliruusi, Jouko

    2009-02-23

    The surfaces of ibuprofen particles (d(50) 42 microm) were modified by coating the particles with diluted aqueous hydroxypropyl methylcellulose (HPMC) solution in an instrumentated top-spray fluid bed granulator. The objective was to evaluate whether an extremely thin polymer coating could be an alternative to granulation in enhancing powder flow and processing properties. The studied variables were inlet air temperature and spray rate. The treated powders showed a clear improvement in flow rate as measured with a flow meter designed for powders with poor flow properties. The particle size was determined using optical microscopy and image analysis. The particle size, size distribution and circularity of the treated and untreated ibuprofen batches showed no difference from each other. Consequently, the improvement in flow properties can be attributed to the trace amounts of hydroxypropyl methylcellulose applied onto the particle surfaces. In conclusion, fluidized bed particle thin-coating (PTC) alters the surface of ibuprofen powder particles and improves the flow properties of ibuprofen powder with changes in neither particle size, size distribution nor morphology.

  5. Cold-Flow Testing of a Proposed Integrated Center-Body Diffuser/Steam Blocker Concept for Plum Brook Station's B-2 Test Facility

    NASA Technical Reports Server (NTRS)

    Edwards, Daryl A.; Weaver, Harold F; Kastner, Carl E., Jr.

    2009-01-01

    The center-body diffuser (CBD) steam blocker (SB) system is a concept that incorporates a set of secondary drive nozzles into the envelope of a CBD, such that both nozzle systems (i.e., the rocket engine and the steam blocking nozzles) utilize the same supersonic diffuser, and will operate either singularly or concurrently. In this manner, the SB performs as an exhaust system stage when the rocket engine is not operating, and virtually eliminates discharge flow on rocket engine shutdown. A 2.25-percent scale model of a proposed SB integrated into a diffuser for the Plum Brook B-2 facility was constructed and cold-flow tested for the purpose of evaluating performance characteristics of various design options. These specific design options addressed secondary drive nozzle design (method of steam injection), secondary drive nozzle location relative to CBD throat, and center-body throat length to diameter (L/D) ratios. The objective of the test program is to identify the desired configuration to carry forward should the next phase of design proceed. The tested scale model can provide data for various pressure ratios; however, its design is based on a proposed B-2 spray chamber (SC) operating pressure of 4.0 psia and a steam supply pressure of 165 psia. Evaluation of the test data acquired during these tests indicate that either the discrete axial or annular nozzle configuration integrated into a CBD, with an annular throat length of 1.5 L/D at the nominal injection position, would be suitable to carry forward from the SB's perspective. Selection between these two then becomes more a function of constructability and implementation than performance. L/D also has some flexibility, and final L/D selection can be a function of constructability issues within a limited range.

  6. Effects of static contraction and cold stimulation on cardiovascular autonomic indices, trapezius blood flow and muscle activity in chronic neck-shoulder pain.

    PubMed

    Hallman, David M; Lindberg, Lars-Göran; Arnetz, Bengt B; Lyskov, Eugene

    2011-08-01

    The aim of the present study was to investigate reactions in trapezius muscle blood flow (MBF), muscle activity, heart rate variability (HRV) and systemic blood pressure (BP) to autonomic tests in subjects with chronic neck-shoulder pain and healthy controls. Changes in muscle activity and blood flow due to stress and unfavourable muscle loads are known underlying factors of work-related muscle pain. Aberration of the autonomic nervous system (ANS) is considered a possible mechanism. In the present study, participants (n = 23 Pain, n = 22 Control) performed autonomic tests which included a resting condition, static hand grip test (HGT) at 30% of maximal voluntary contraction, a cold pressor test (CPT) and a deep breathing test (DBT). HRV was analysed in time and frequency domains. MBF and muscle activity were recorded from the upper trapezius muscles using photoplethysmography and electromyography (EMG). The pain group showed reduced low frequency-HRV (LF) and SDNN during rest, as well as a blunted BP response and increased LF-HRV during HGT (∆systolic 22 mm Hg; ∆LF(nu) 27%) compared with controls (∆systolic 27; ∆LF(nu) 6%). Locally, the pain group had attenuated trapezius MBF in response to HGT (Pain 122% Control 140%) with elevated trapezius EMG following HGT and during CPT. In conclusion, only HGT showed differences between groups in systemic BP and HRV and alterations in local trapezius MBF and EMG in the pain group. Findings support the hypothesis of ANS involvement at systemic and local levels in chronic neck-shoulder pain.

  7. Trace mercury determination in drinking and natural water samples by room temperature ionic liquid based-preconcentration and flow injection-cold vapor atomic absorption spectrometry.

    PubMed

    Martinis, Estefanía M; Bertón, Paula; Olsina, Roberto A; Altamirano, Jorgelina C; Wuilloud, Rodolfo G

    2009-08-15

    A liquid-liquid extraction procedure (L-L) based on room temperature ionic liquid (RTIL) was developed for the preconcentration and determination of mercury in different water samples. The analyte was quantitatively extracted with 1-butyl-3-methylimidazolium hexafluorophosphate ([C(4)mim][PF(6)]) under the form of Hg-2-(5-bromo-2-pyridylazo)-5-diethylaminophenol (Hg-5-Br-PADAP) complex. A volume of 500 microl of 9.0 mol L(-1) hydrochloric acid was used to back-extract the analyte from the RTIL phase into an aqueous media prior to its analysis by flow injection-cold vapor atomic absorption spectrometry (FI-CV-AAS). A preconcentration factor of 36 was achieved upon preconcentration of 20 mL of sample. The limit of detection (LOD) obtained under the optimal conditions was 2.3ngL(-1) and the relative standard deviation (RSD) for 10 replicates at 1 microg L(-1) Hg(2+) was 2.8%, calculated with peaks height. The method was successfully applied to the determination of mercury in river, sea, mineral and tap water samples and a certified reference material (CRM).

  8. Remote Ischemic Conditioning Improves Blood Flow and Oxygen Saturation in Pedicled and Free Surgical Flaps.

    PubMed

    Kolbenschlag, Jonas; Sogorski, Alexander; Kapalschinski, Nicolai; Harati, Kamran; Lehnhardt, Marcus; Daigeler, Adrien; Hirsch, Tobias; Goertz, Ole

    2016-11-01

    Surgical flaps have become safe and reliable reconstructive tools, but total flap loss rates as high as 25 percent and partial flap loss rates as high as 36 percent have been reported due to insufficient perfusion. Therefore, a reliable, noninvasive, and effective way to improve the microcirculation of surgical flaps is desirable. The aim of this study was to assess the effect of remote ischemic conditioning on the microcirculation of pedicled and free surgical flaps. Thirty patients undergoing free (n = 20) and pedicled (n = 10) tissue transfer were included in this study. Remote ischemic conditioning was applied on the upper extremity for three cycles on postoperative days 1, 5, and 12. Blood flow, tissue oxygen saturation, and relative hemoglobin content were measured by means of a combination of laser Doppler and spectroscopy (O2C device) in the flap and the surrounding tissue. The relative increase compared with baseline measurements was assessed. Blood flow increased significantly in controls on all 3 postoperative days (p < 0.05 for all). In free flaps, tissue oxygen saturation improved significantly on postoperative days 1 and 12 and blood flow improved significantly on postoperative days 5 and 12 (p < 0.05). In pedicled flaps, blood flow and tissue oxygen saturation increased on postoperative day12, but not significantly. Remote ischemic conditioning is a safe, inexpensive, fast, and reliable method to improve the microcirculation of surgical flaps. Further research is warranted to see whether such an improvement translates into improved flap survival, but it is likely. Therapeutic, IV.

  9. Method and apparatus for improved melt flow during continuous strip casting

    DOEpatents

    Follstaedt, D.W.; King, E.L.; Schneider, K.C.

    1991-11-12

    The continuous casting of metal strip using the melt overflow process is improved by controlling the weir conditions in the nozzle to provide a more uniform flow of molten metal across the width of the nozzle and reducing the tendency for freezing of metal along the interface with refractory surfaces. A weir design having a sloped rear wall and tapered sidewalls and critical gap controls beneath the weir has resulted in the drastic reduction in edge tearing and a significant improvement in strip uniformity. The floor of the container vessel is preferably sloped and the gap between the nozzle and the rotating substrate is critically controlled. The resulting flow patterns observed with the improved casting process have reduced thermal gradients in the bath, contained surface slag and eliminated undesirable solidification near the discharge area by increasing the flow rates at those points. 8 figures.

  10. Method and apparatus for improved melt flow during continuous strip casting

    DOEpatents

    Follstaedt, Donald W.; King, Edward L.; Schneider, Ken C.

    1991-11-12

    The continuous casting of metal strip using the melt overflow process is improved by controlling the weir conditions in the nozzle to provide a more uniform flow of molten metal across the width of the nozzle and reducing the tendency for freezing of metal along the interface with refractory surfaces. A weir design having a sloped rear wall and tapered sidewalls and critical gap controls beneath the weir has resulted in the drastic reduction in edge tearing and a significant improvement in strip uniformity. The floor of the container vessel is preferably sloped and the gap between the nozzle and the rotating substrate is critically controlled. The resulting flow patterns observed with the improved casting process have reduced thermal gradients in the bath, contained surface slag and eliminated undesirable solidification near the discharge area by increasing the flow rates at those points.

  11. Dopamine treatment of brain-dead Fisher rats improves renal histology but not early renal function in Lewis recipients after prolonged static cold storage.

    PubMed

    Fontana, J; Yard, B; Stamellou, E; Wenz, H; Benck, U; Schnuelle, P; Hoeger, S

    2014-12-01

    Brain death (BD) and cold preservation are major risk factors for an unfavorable transplantation outcome. Although donor dopamine treatment in brain-dead rats improves renal function and histology in allogeneic recipients, it remains to be assessed if this also holds true for the combinations of BD and prolonged static cold preservation. BD was induced in F344 donor rats, which were subsequently treated with NaCl 1 mL/h (BD, n = 11), NaCl/hydroxy ethyl starch (BD-norm, n = 10), or 10 μg/min/kg dopamine (BD-dopa, n = 10). Renal grafts were harvested 4 h after BD and transplanted into bilateral nephrectomized Lewis recipients 6 h after cold preservation in University of Wisconsin solution. Renal function was evaluated by use of serum creatinine and urea concentrations at days 0, 1, 3, 5, and 10. Ten days after transplantation, recipients were killed and the renal allografts were processed for light microscopy and immune histology. Serum urea concentrations at days 5 and 10 were significantly lower in recipients that received a renal graft from dopamine-treated rats; for serum creatinine, only a trend was observed at day 10. Immune histology revealed a lower degree of ED1-positive cells in the donor dopamine-treated group. Under light microscopy, Banff classification revealed significantly less intimal arteritis in these grafts (P < .05). Although donor dopamine treatment clearly improves renal histology in this model, the beneficial effect on early renal function was marginal. It remains to be assessed if donor dopamine treatment has a beneficial effect on renal function in long-term follow-up. Copyright © 2014 Elsevier Inc. All rights reserved.

  12. An Improved Lattice Boltzmann Model for Non-Newtonian Flows with Applications to Solid-Fluid Interactions in External Flows

    NASA Astrophysics Data System (ADS)

    Adam, Saad; Premnath, Kannan

    2016-11-01

    Fluid mechanics of non-Newtonian fluids, which arise in numerous settings, are characterized by non-linear constitutive models that pose certain unique challenges for computational methods. Here, we consider the lattice Boltzmann method (LBM), which offers some computational advantages due to its kinetic basis and its simpler stream-and-collide procedure enabling efficient simulations. However, further improvements are necessary to improve its numerical stability and accuracy for computations involving broader parameter ranges. Hence, in this study, we extend the cascaded LBM formulation by modifying its moment equilibria and relaxation parameters to handle a variety of non-Newtonian constitutive equations, including power-law and Bingham fluids, with improved stability. In addition, we include corrections to the moment equilibria to obtain an inertial frame invariant scheme without cubic-velocity defects. After preforming its validation study for various benchmark flows, we study the physics of non-Newtonian flow over pairs of circular and square cylinders in a tandem arrangement, especially the wake structure interactions and their effects on resulting forces in each cylinder, and elucidate the effect of the various characteristic parameters.

  13. Improvement of the Operational Settings of a Helium Purifier, Leading to a Higher Purity of the Recovered Gas

    NASA Astrophysics Data System (ADS)

    Ikeda, Hiroshi; Kondo, Yutaka

    The internal purifier operating conditions of commercially available helium liquefiers are determined by adjusting the cold end temperature, the cold flow, the regeneration completion temperature and the heater temperature. By changing the cold end temperature of the internal purifier from 32.5 K to 22 K, it was possible to improve the purity of the helium gas recovered from the purifier from 33.5 to 99%. The current internal purifier regeneration operation settings are as follows: cold end temperature 22 K, cold flow rate 180 ℓ/min, and regeneration completion temperature 145 K. This paper describes how the internal purifier system of a helium liquefier was improved.

  14. Characterization of neonatal aortic cannula jet flow regimes for improved cardiopulmonary bypass.

    PubMed

    Menon, Prahlad G; Teslovich, Nikola; Chen, Chia-Yuan; Undar, Akif; Pekkan, Kerem

    2013-01-18

    During pediatric and neonatal cardiopulmonary bypass (CPB), tiny aortic outflow cannulae (2-3 mm inner diameter), with micro-scale blood-wetting features transport relatively large blood volumes (0.3 to 1.0 L/min) resulting in high blood flow velocities (2 to 5 m/s). These severe flow conditions are likely to complement platelet activation, release pro-inflammatory cytokines, and further result in vascular and blood damage. Hemodynamically efficient aortic outflow cannulae are required to provide high blood volume flow rates at low exit force. In addition, optimal aortic insertion strategies are necessary in order to alleviate hemolytic risk, post-surgical neurological complications and developmental defects, by improving cerebral perfusion in the young patient. The methodology and results presented in this study serve as a baseline for design of superior aortic outflow cannulae. In this study, direct numerical simulation (DNS) computational fluid dynamics (CFD) was employed to delineate baseline hemodynamic performance of jet wakes emanating from microCT scanned state-of-the-art pediatric cannula tips in a cuboidal test rig operating at physiologically relevant laminar and turbulent Reynolds numbers (Re: 650-2150 , steady inflow). Qualitative and quantitative validation of CFD simulated device-specific jet wakes was established using time-resolved flow visualization and particle image velocimetry (PIV). For the standard end-hole cannula tip design, blood damage indices were further numerically assessed in a subject-specific cross-clamped neonatal aorta model for different cannula insertion configurations. Based on these results, a novel diffuser type cannula tip is proposed for improved jet flow-control, decreased blood damage and exit force and increased permissible flow rates. This study also suggests that surgically relevant cannula orientation parameters such as outflow angle and insertion depth may be important for improved hemodynamic performance. The jet

  15. Model-based reconstruction for real-time phase-contrast flow MRI: Improved spatiotemporal accuracy.

    PubMed

    Tan, Zhengguo; Roeloffs, Volkert; Voit, Dirk; Joseph, Arun A; Untenberger, Markus; Merboldt, K Dietmar; Frahm, Jens

    2017-03-01

    To develop a model-based reconstruction technique for real-time phase-contrast flow MRI with improved spatiotemporal accuracy in comparison to methods using phase differences of two separately reconstructed images with differential flow encodings. The proposed method jointly computes a common image, a phase-contrast map, and a set of coil sensitivities from every pair of flow-compensated and flow-encoded datasets obtained by highly undersampled radial FLASH. Real-time acquisitions with five and seven radial spokes per image resulted in 25.6 and 35.7 ms measuring time per phase-contrast map, respectively. The signal model for phase-contrast flow MRI requires the solution of a nonlinear inverse problem, which is accomplished by an iteratively regularized Gauss-Newton method. Aspects of regularization and scaling are discussed. The model-based reconstruction was validated for a numerical and experimental flow phantom and applied to real-time phase-contrast MRI of the human aorta for 10 healthy subjects and 2 patients. Under all conditions, and compared with a previously developed real-time flow MRI method, the proposed method yields quantitatively accurate phase-contrast maps (i.e., flow velocities) with improved spatial acuity, reduced phase noise and reduced streaking artifacts. This novel model-based reconstruction technique may become a new tool for clinical flow MRI in real time. Magn Reson Med 77:1082-1093, 2017. © 2016 International Society for Magnetic Resonance in Medicine. © 2016 International Society for Magnetic Resonance in Medicine.

  16. Facilitators and barriers to the implementation of patient flow improvement strategies.

    PubMed

    Van Dyke, Kevin J; McHugh, Megan; Yonek, Julie; Moss, Dina

    2011-01-01

    Patient flow improvement strategies have been effective in reducing emergency department (ED) crowding, but little guidance is available on the implementation process. By using a qualitative research design, our objective was to identify common facilitators and barriers to the implementation of patient flow improvement strategies and successful approaches for mitigating barriers. Six hospitals participated in an 18-month Urgent Matters learning network launched in October 2008. The hospitals selected strategies to improve patient flow that could be implemented within 3 months with measurable impact. Across 6 hospitals, 8 strategies were implemented. We conducted 2 rounds of key informant interviews with improvement teams, for a total of 129 interviews. Interviews were recorded, transcribed, and coded by using a grounded theory approach to identify common themes. Factors facilitating implementation included participation in the learning network and strategic selection of team members. Common challenges included staff resistance and entrenched organizational culture. Some of the challenges were mitigated through approaches such as staff education and department leaders' constant reinforcement. Our findings indicate that several facilitators and barriers are common to the implementation of different strategies. Leveraging facilitators and developing a strategy to address common barriers may leave hospital and ED leaders better prepared to implement patient flow improvement strategies.

  17. Cold intolerance

    MedlinePlus

    Some causes of cold intolerance are: Anemia Anorexia nervosa Blood vessel problems, such as Raynaud phenomenon Chronic severe illness General poor health Underactive thyroid ( hypothyroidism ) Problem with the hypothalamus (a part ...

  18. Improved resolution of ambient flow through fractured rock with temperature logs.

    PubMed

    Pehme, P E; Parker, B L; Cherry, J A; Greenhouse, J P

    2010-01-01

    In contaminant hydrogeology, investigations at fractured rock sites are typically undertaken to improve understanding of the fracture networks and associated groundwater flow that govern past and/or future contaminant transport. Conventional hydrogeologic, geophysical, and hydrophysical techniques used to develop a conceptual model are often implemented in open boreholes under conditions of cross-connected flow. A new approach using high-resolution temperature (+/-0.001 degrees C) profiles measured within static water columns of boreholes sealed using continuous, water-inflated, flexible liners (FLUTe) identifies hydraulically active fractures under ambient (natural) groundwater flow conditions. The value of this approach is assessed by comparisons of temperature profiles from holes (100 to 200 m deep) with and without liners at four contaminated sites with distinctly different hydrogeologic conditions. The results from the lined holes consistently show many more hydraulically active fractures than the open-hole profiles, in which the influence of vertical flow through the borehole between a few fractures masks important intermediary flow zones. Temperature measurements in temporarily sealed boreholes not only improve the sensitivity and accuracy of identifying hydraulically active fractures under ambient conditions but also offer new insights regarding previously unresolvable flow distributions in fractured rock systems, while leaving the borehole available for other forms of testing and monitoring device installation.

  19. Device specific analysis of neonatal aortic outflow cannula jet flows for improved cardiopulmonary bypass hemodynamics

    NASA Astrophysics Data System (ADS)

    Menon, Prahlad; Sotiropoulos, Fotis; Undar, Akif; Pekkan, Kerem

    2011-11-01

    Hemodynamically efficient aortic outflow cannulae can provide high blood volume flow rates at low exit force during extracorporeal circulation in pediatric or neonatal cardiopulmonary bypass repairs. Furthermore, optimal hemolytic aortic insertion configurations can significantly reduce risk of post-surgical neurological complications and developmental defects in the young patient. The methodology and results presented in this study serve as a baseline for design of superior aortic outflow cannulae based on a novel paradigm of characterizing jet-flows at different flow regimes. In-silico evaluations of multiple cannula tips were used to delineate baseline hemodynamic performance of the popular pediatric cannula tips in an experimental cuboidal test-rig, using PIV. High resolution CFD jet-flow simulations performed for various cannula tips in the cuboidal test-rig as well as in-vivo insertion configurations have suggested the existence of optimal surgically relevant characteristics such as cannula outflow angle and insertion depth for improved hemodynamic performance during surgery. Improved cannula tips were designed with internal flow-control features for decreased blood damage and increased permissible flow rates.

  20. Improving flow and spillage characteristics of range hoods by using an inclined air-curtain technique.

    PubMed

    Huang, Rong Fung; Nian, You-Cyun; Chen, Jia-Kun; Peng, Kuan-Lin

    2011-03-01

    The current study developed a new type of range hood, which was termed an 'inclined air-curtain range hood', in order to improve the flow and performance of the conventionally used wall-mounted range hood. The flow characteristics and oil mist spillages of air-curtain and conventional range hoods under the influences of both a mannequin presence and a simulated walk-by motion were experimentally examined. The study examined flow patterns by using a laser-light-sheet-assisted smoke-flow visualization technique and diagnosed spillages by using the tracer gas concentration test method. A mannequin presented in front of the conventional hood induced turbulent dispersion of oil mists toward the chest and nose of the mannequin owing to the complex interaction among the suction, wake, and wall effect, while the inclined air-curtain hood presented excellent hood performance by isolating the oil mists from the mannequin with an air curtain and therefore could reduce spillages out into the atmosphere and the mannequin's breathing zone. Both flow visualization and the tracer gas test indicated that the air-curtain hood had excellent 'robustness' over the conventional hood in resisting the influence of walk-by motion. The air-curtain technique could drastically improve the flow characteristics and performance of the range hood by consuming less energy.

  1. Architecture for improved mass transport and system performance in redox flow batteries

    NASA Astrophysics Data System (ADS)

    Houser, Jacob; Pezeshki, Alan; Clement, Jason T.; Aaron, Douglas; Mench, Matthew M.

    2017-05-01

    In this work, electrochemical performance and parasitic losses are combined in an overall system-level efficiency metric for a high performance, all-vanadium redox flow battery. It was found that pressure drop and parasitic pumping losses are relatively negligible for high performance cells, i.e., those capable of operating at a high current density while at a low flow rate. Through this finding, the Equal Path Length (EPL) flow field architecture was proposed and evaluated. This design has superior mass transport characteristics in comparison with the standard serpentine and interdigitated designs at the expense of increased pressure drop. An Aspect Ratio (AR) design is discussed and evaluated, which demonstrates decreased pressure drop compared to the EPL design, while maintaining similar electrochemical performance under most conditions. This AR design is capable of leading to improved system energy efficiency for flow batteries of all chemistries.

  2. Juncture flow improvement for wing/pylon configurations by using CFD methodology

    NASA Technical Reports Server (NTRS)

    Gea, Lie-Mine; Chyu, Wei J.; Stortz, Michael W.; Chow, Chuen-Yen

    1993-01-01

    Transonic flow field around a fighter wing/pylon configuration was simulated by using an implicit upwinding Navier-Stokes flow solver (F3D) and overset grid technology (Chimera). Flow separation and local shocks near the wing/pylon junction were observed in flight and predicted by numerical calculations. A new pylon/fairing shape was proposed to improve the flow quality. Based on numerical results, the size of separation area is significantly reduced and the onset of separation is delayed farther downstream. A smoother pressure gradient is also obtained near the junction area. This paper demonstrates that computational fluid dynamics (CFD) methodology can be used as a practical tool for aircraft design.

  3. Juncture flow improvement for wing/pylon configurations by using CFD methodology

    NASA Technical Reports Server (NTRS)

    Gea, Lie-Mine; Chyu, Wei J.; Stortz, Michael W.; Chow, Chuen-Yen

    1993-01-01

    Transonic flow field around a fighter wing/pylon configuration was simulated by using an implicit upwinding Navier-Stokes flow solver (F3D) and overset grid technology (Chimera). Flow separation and local shocks near the wing/pylon junction were observed in flight and predicted by numerical calculations. A new pylon/fairing shape was proposed to improve the flow quality. Based on numerical results, the size of separation area is significantly reduced and the onset of separation is delayed farther downstream. A smoother pressure gradient is also obtained near the junction area. This paper demonstrates that computational fluid dynamics (CFD) methodology can be used as a practical tool for aircraft design.

  4. From surface wave to cloud: An atmosphere physical process in improving the too cold tongue bias and precipitation in a climate model

    NASA Astrophysics Data System (ADS)

    Song, Yajuan; Qiao, Fangli; Song, Zhenya

    2015-04-01

    The coupled atmospheric-ocean general circulation models (AOGCMs) without flux correction still show defects in simulating sea surface temperature (SST) and precipitation, with too cold tongue and obvious double-ITCZ biases in the tropical Pacific. We make an effort to improve SST too cold tongue bias and the north-south asymmetry of zonal-averaged precipitation distribution in the Community Climate System Model version3 (CCSM3) by incorporating the non-breaking wave-induced vertical mixing. The oceanic thermocline depth deepens in the central and eastern tropical Pacific under the wave mixing effect. SST warming characterized as a conspicuous maximum in the central and eastern equatorial Pacific contributes to moisture increasing in atmosphere through evaporation process. The non-uniform SST brings out distinct horizontal gradient in air pressure across the tropics, which result in an abnormal wind convergence in the central Pacific. As a result, an enhanced Walker circulation and Hadley cell are driven by wind gradient and more latent heat. The subsidence branch of the Walker circulation in the eastern Pacific suppress the formation of clouds, so that more shortwave radiation is absorbed by the ocean. However, in the central to western Pacific, the updraft of the Walker circulation with abundant water vapor provides favorable conditions for cloud formation in middle and high troposphere. A positive feedback between water vapor and cloud fraction warms the SST by less longwave radiation releasing. The warm anomalies in the central and eastern Pacific restrict the westward expansion of cold tongue. Furthermore, the intensive updraft of Hadley circulation with high humidity increases rainfall in the low-latitudes of the northern hemisphere.

  5. Interim Columbia and Snake rivers flow improvement measures for salmon: Final Supplemental Environmental Impact Statement (SEIS)

    SciTech Connect

    Not Available

    1993-03-01

    Public comments are sought on this final SEIS, which supplements the 1992 Columbia River Salmon Flow Measures Options Analysis (OA)/Environmental Impact Statement (EIS). The Corps of Engineers, in cooperation with the Bonneville Power Administration and the Bureau of Reclamation proposes five alternatives to improve flows of water in the lower Columbia-Snake rivers in 1993 and future years to assist the migration of juvenile and adult anadromous fish past eight hydropower dams. These are: (1) Without Project (no action) Alternative, (2) the 1992 Operation, (3) the 1992 Operation with Libby/Hungry Horse Sensitivity, (4) a Modified 1992 Operation with Improvements to Salmon Flows from Dworshak, and (5) a Modified 1992 Operation with Upper Snake Sensitivity. Alternative 4, Modified 1992 Operations, has been identified as the preferred alternative.

  6. An improved version of NCOREL: A computer program for 3-D nonlinear supersonic potential flow computations

    NASA Technical Reports Server (NTRS)

    Siclari, Michael J.

    1988-01-01

    A computer code called NCOREL (for Nonconical Relaxation) has been developed to solve for supersonic full potential flows over complex geometries. The method first solves for the conical at the apex and then marches downstream in a spherical coordinate system. Implicit relaxation techniques are used to numerically solve the full potential equation at each subsequent crossflow plane. Many improvements have been made to the original code including more reliable numerics for computing wing-body flows with multiple embedded shocks, inlet flow through simulation, wake model and entropy corrections. Line relaxation or approximate factorization schemes are optionally available. Improved internal grid generation using analytic conformal mappings, supported by a simple geometric Harris wave drag input that was originally developed for panel methods and internal geometry package are some of the new features.

  7. The electronic image stabilization technology research based on improved optical-flow motion vector estimation

    NASA Astrophysics Data System (ADS)

    Wang, Chao; Ji, Ming; Zhang, Ying; Jiang, Wentao; Lu, Xiaoyan; Wang, Jiaoying; Yang, Heng

    2016-01-01

    The electronic image stabilization technology based on improved optical-flow motion vector estimation technique can effectively improve the non normal shift, such as jitter, rotation and so on. Firstly, the ORB features are extracted from the image, a set of regions are built on these features; Secondly, the optical-flow vector is computed in the feature regions, in order to reduce the computational complexity, the multi resolution strategy of Pyramid is used to calculate the motion vector of the frame; Finally, qualitative and quantitative analysis of the effect of the algorithm is carried out. The results show that the proposed algorithm has better stability compared with image stabilization based on the traditional optical-flow motion vector estimation method.

  8. Improving cash flow in a down economy. How HIM can help reduce denials.

    PubMed

    Dunn, Rose

    2009-03-01

    Maybe HIM professionals can't ease tight credit or reduce bad debt, but they can make sure their organizations get full, correct reimbursement on the first submission. HIM professionals help improve cash flow by contributing to revenue cycle management n these tough economic times-when increases in bad

  9. Atorvastatin preconditioning improves the forward blood flow in the no-reflow rats.

    PubMed

    Shao, Liang; Zhang, Yong; Ma, Aiqun; Zhang, Ping; Wu, Dayin; Li, Wenzhu; Wang, Jue; Liu, Kun; Wang, Zhaohui

    2014-02-01

    Atorvastatin is not only an antilipemic but also used as an anti-inflammatory medicine in heart disease. Our working hypothesis was that atorvastatin preconditioning could improve the forward blood flow in the no-reflow rats associated with inflammation. We investigated that two doses of atorvastatin preconditioning (20 and 5 mg/kg/day) could alleviate deterioration of early cardiac diastolic function in rats with inflammation detected by echocardiography and haemodynamics. This benefit was obtained from the effect of atorvastatin preconditioning on improving forward blood flow and preserving the infarct cardiomyocytes, which was estimated by Thioflavin S and TTC staining in rats with myocardial ischemia/reperfusion. Subsequently, the improving of forward blood flow was ascribed to reduction of microthrombus in microvascular and myocardial fibrosis observed by MSB and Masson's trichrome staining with atorvastatin preconditioning. Ultimately, we found that atorvastatin preconditioning could reduce inflammation factor, such as tumor necrosis factor-α and fibrinogen-like protein 2, both in myocardial and in mononuclear cells, which probably attribute to microcirculation dysfunction in no-reflow rats detected by immunohistochemistry staining, western blot, and ELISA detection, respectively. In conclusion, atorvastatin preconditioning could alleviate deterioration of early cardiac diastolic function and improve the forward blood flow in the no-reflow rats attributing to reduction of TNF-α and fgl-2 expression.

  10. Assessing the potential for improved scramjet performance through application of electromagnetic flow control

    NASA Astrophysics Data System (ADS)

    Lindsey, Martin Forrester

    Sustained hypersonic flight using scramjet propulsion is the key technology bridging the gap between turbojets and the exoatmospheric environment where a rocket is required. Recent efforts have focused on electromagnetic (EM) flow control to mitigate the problems of high thermomechanical loads and low propulsion efficiencies associated with scramjet propulsion. This research effort is the first flight-scale, three-dimensional computational analysis of a realistic scramjet to determine how EM flow control can improve scramjet performance. Development of a quasi-one dimensional design tool culminated in the first open source geometry of an entire scramjet flowpath. This geometry was then tested extensively with the Air Force Research Laboratory's three-dimensional Navier-Stokes and EM coupled computational code. As part of improving the model fidelity, a loosely coupled algorithm was developed to incorporate thermochemistry. This resulted in the only open-source model of fuel injection, mixing and combustion in a magnetogasdynamic (MGD) flow controlled engine. In addition, a control volume analysis tool with an electron beam ionization model was presented for the first time in the context of the established computational method used. Local EM flow control within the internal inlet greatly impacted drag forces and wall heat transfer but was only marginally successful in raising the average pressure entering the combustor. The use of an MGD accelerator to locally increase flow momentum was an effective approach to improve flow into the scramjet's isolator. Combustor-based MGD generators proved superior to the inlet generator with respect to power density and overall engine efficiency. MGD acceleration was shown to be ineffective in improving overall performance, with all of the bypass engines having approximately 33% more drag than baseline and none of them achieving a self-powered state.

  11. Cold energy

    SciTech Connect

    Wallace, John P.

    2015-12-04

    Deviations in Q for resonant superconducting radio frequency niobium accelerator cavities are generally correlated with resistivity loss mechanisms. Field dependent Qs are not well modeled by these classical loss mechanisms, but rather can represent a form of precision cavity surface thermometry. When the field dependent Q variation shows improvement with increasing B field level the classical treatment of this problem is inadequate. To justify this behavior hydrogen as a ubiquitous impurity in niobium, which creates measurable property changes, even at very low concentrations is typically considered the cause of such anomalous behavior. This maybe the case in some instances, but more importantly any system operating with a highly coherent field with a significant time dependent magnetic component at near 2° K will have the ability to organize the remaining free spins within the London penetration depth to form a coupled energy reservoir in the form of low mass spin waves. The niobium resonant cavities are composed of a single isotope with a large nuclear spin. When the other loss mechanisms are stripped away this may be the gain medium activated by the low level residual magnetic fields. It was found that one resonant cavity heat treatment produced optimum surface properties and then functioned as a MASER extracting energy from the 2° K thermal bath while cooling the cavity walls. The cavity operating in this mode is a simulator of what can take place in the wider but not colder universe using the cosmic microwave background (CMB) as a thermal source. The low mass, long lifetimes, and the scale of the magnetic spin waves on the weakly magnetized interstellar medium allows energy to be stored that is many orders of magnitude colder than the cosmic microwave background. A linear accelerator cavity becomes a tool to explore the properties of the long wave length magnetic spin waves that populate this cold low energy regime.

  12. Cold energy

    NASA Astrophysics Data System (ADS)

    Wallace, John P.

    2015-12-01

    Deviations in Q for resonant superconducting radio frequency niobium accelerator cavities are generally correlated with resistivity loss mechanisms. Field dependent Qs are not well modeled by these classical loss mechanisms, but rather can represent a form of precision cavity surface thermometry. When the field dependent Q variation shows improvement with increasing B field level the classical treatment of this problem is inadequate. To justify this behavior hydrogen as a ubiquitous impurity in niobium, which creates measurable property changes, even at very low concentrations is typically considered the cause of such anomalous behavior. This maybe the case in some instances, but more importantly any system operating with a highly coherent field with a significant time dependent magnetic component at near 2° K will have the ability to organize the remaining free spins within the London penetration depth to form a coupled energy reservoir in the form of low mass spin waves. The niobium resonant cavities are composed of a single isotope with a large nuclear spin. When the other loss mechanisms are stripped away this may be the gain medium activated by the low level residual magnetic fields. It was found that one resonant cavity heat treatment produced optimum surface properties and then functioned as a MASER extracting energy from the 2° K thermal bath while cooling the cavity walls. The cavity operating in this mode is a simulator of what can take place in the wider but not colder universe using the cosmic microwave background (CMB) as a thermal source. The low mass, long lifetimes, and the scale of the magnetic spin waves on the weakly magnetized interstellar medium allows energy to be stored that is many orders of magnitude colder than the cosmic microwave background. A linear accelerator cavity becomes a tool to explore the properties of the long wave length magnetic spin waves that populate this cold low energy regime.

  13. Improvements to a Flow Sensor for Liquid Bismuth-Fed Hall Thrusters

    NASA Technical Reports Server (NTRS)

    Bonds, Kevin; Polzin, Kurt A.

    2010-01-01

    Recently, there has been significant interest in using bismuth metal as a propellant in Hall Thrusters [1, 2]. Bismuth offers some considerable cost, weight, and space savings over the traditional propellant--xenon. Quantifying the performance of liquid metal-fed Hall thrusters requires a very precise measure of the low propellant flow rates [1, 2]. The low flow rates (10 mg/sec) and the temperature at which free flowing liquid bismuth exists (above 300 C) preclude the use of off-the-shelf flow sensing equipment [3]. Therefore a new type of sensor is required. The hotspot bismuth flow sensor, described in Refs. [1-5] is designed to perform a flow rate measurement by measuring the velocity at which a thermal feature moves through a flow chamber. The mass flow rate can be determined from the time of flight of the thermal peak, [4, 5]. Previous research and testing has been concerned mainly with the generation of the thermal peak and it's subsequent detection. In this paper, we present design improvements to the sensor concept; and the results of testing conducted to verify the functionality of these improvements. A ceramic material is required for the sensor body (see Fig. 1), which must allow for active heating of the bismuth flow channel to keep the propellant in a liquid state. The material must be compatible with bismuth and must be bonded to conductive elements to allow for conduction of current into the liquid metal and measurement of the temperature in the flow. The new sensor requires fabrication techniques that will allow for a very small diameter flow chamber, which is required to produce useful measurements. Testing of various materials has revealed several that are potentially compatible with liquid bismuth. Of primary concern in the fabrication and testing of a robust, working prototype, is the compatibility of the selected materials with one another. Specifically, the thermal expansion rates of the materials relative to the ceramic body cannot expand so

  14. From the similarities between neutrons and radon to advanced radon-detection and improved cold fusion neutron-measurements

    NASA Astrophysics Data System (ADS)

    Tommasino, L.; Espinosa, G.

    2014-07-01

    Neutrons and radon are both ubiquitous in the earth's crust. The neutrons of terrestrial origin are strongly related to radon since they originate mainly from the interactions between the alpha particles from the decays of radioactive-gas (namely Radon and Thoron) and the light nuclei. Since the early studies in the field of neutrons, the radon gas was used to produce neutrons by (α, n) reactions in beryllium. Another important similarity between radon and neutrons is that they can be detected only through the radiations produced respectively by decays or by nuclear reactions. These charged particles from the two distinct nuclear processes are often the same (namely alpha-particles). A typical neutron detector is based on a radiator facing a alpha-particle detector, such as in the case of a neutron film badge. Based on the similarity between neutrons and radon, a film badge for radon has been recently proposed. The radon film badge, in addition to be similar, may be even identical to the neutron film badge. For these reasons, neutron measurements can be easily affected by the presence of unpredictable large radon concentration. In several cold fusion experiments, the CR-39 plastic films (typically used in radon and neutron film-badges), have been the detectors of choice for measuring neutrons. In this paper, attempts will be made to prove that most of these neutron-measurements might have been affected by the presence of large radon concentrations.

  15. Rapid isolation, reliable characterization, and water solubility improvement of polymethoxyflavones from cold-pressed mandarin essential oil.

    PubMed

    Russo, Marina; Rigano, Francesca; Arigò, Adriana; Sciarrone, Danilo; Calabrò, Maria Luisa; Farnetti, Sara; Dugo, Paola; Mondello, Luigi

    2016-06-01

    Polymethoxyflavones possess many biological properties, as lipid-lowering, hypoglycaemic, anti-inflammatory, antioxidant, and anticancer activities, therefore, they may be employed as nutraceuticals or therapeutic agents. The scarcity of pure polymethoxyflavones on the market as well as their low water solubility limited in vivo studies and the use of polymethoxyflavones as food or pharmaceutical supplements. Since mandarin peels are a rich source of polymethoxyflavones, tangeretin, nobiletin, sinensetin, tetra-O-methyl scutellarein, and heptamethoxyflavone were purified from a nonvolatile residue of a cold-pressed mandarin essential oil using a multidimensional preparative liquid chromatographic system coupled with a photodiode array detector and a single quadrupole mass spectrometer. A new prototype, consisting of a nano-liquid chromatography system coupled with an electron ionization mass spectrometer, was used for the characterization of the pure isolated molecules. Finally, due to the collection of highly pure nobiletin and tangeretin, the ability of 2-hydroxypropyl-β-cyclodextrin to enhance the water solubility of both polymethoxyflavones was evaluated by phase solubility studies and Job's plot method.

  16. Improved transport properties and connectivity of in situ MgB 2 wires obtained by Cold High Pressure Densification (CHPD)

    NASA Astrophysics Data System (ADS)

    Flükiger, R.; Hossain, M. S. A.; Senatore, C.; Rindfleisch, M.

    2011-11-01

    The critical current density, Jc, of in situ MgB2 wires with C4H6O5 (malic acid) has been strongly enhanced by means of Cold High Pressure Densification (CHPD) at pressures up to 2.5 GPa prior to reaction. An increase in Jc by factors 2 and 8 was observed at 4.2 and 20 K, regardless of the applied field. Densified wires were found to exhibit a higher homogeneity due to enhanced connectivity. In addition, a higher C content was found, as shown by the lattice parameter change, the decrease of Tc, the shift of the calorimetric Tc distribution and a reduced anisotropy in tapes obtained from the same wires. The higher C content in densified wires is responsible for the observed enhancement of Birr by more than 1 T, up to 11 T at 20 K. Almost isotropic Jc values were obtained for C4H6O5 added square wires of 1 × 0.6 mm2 cross section, the values of Jc(4.2 K) = 1 × 104 A/cm2 for fields // and ⊥ to the wider surface being obtained at 13.8 and 13.1 T (1 μV/cm criterion), the values for 20 K being 6.4 and 6.2 T, respectively. The method was successfully applied to mono- and multifilamentary wires with lengths up to several meters, suggesting applicability for industrial lengths.

  17. Colloidal mercury (Hg) distribution in soil samples by sedimentation field-flow fractionation coupled to mercury cold vapour generation atomic absorption spectroscopy.

    PubMed

    Santoro, A; Terzano, R; Medici, L; Beciani, M; Pagnoni, A; Blo, G

    2012-01-01

    Diverse analytical techniques are available to determine the particle size distribution of potentially toxic elements in matrices of environmental interest such as soil, sediments, freshwater and groundwater. However, a single technique is often not exhaustive enough to determine both particle size distribution and element concentration. In the present work, the investigation of mercury in soil samples collected from a polluted industrial site was performed by using a new analytical approach which makes use of sedimentation field-flow fractionation (SdFFF) coupled to cold vapour generation electrothermal atomic absorption spectroscopy (CV-ETAAS). The Hg concentration in the SdFFF fractions revealed a broad distribution from about 0.1 to 1 μm, roughly following the particle size distributions, presenting a maximum at about 400-700 nm in diameter. A correlation between the concentration of Hg in the colloidal fraction and organic matter (O.M.) content in the soil samples was als