Raising the Bar: Increased Hydraulic Pressure Allows Unprecedented High Power Densities in Pressure-Retarded Osmosis

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

Straub, AP; Yip, NY; Elimelech, M

2014-01-01

Pressure-retarded osmosis (PRO) has the potential to generate sustainable energy from salinity gradients. PRO is typically considered for operation with river water and seawater, but a far greater energy of mixing can be harnessed from hypersaline solutions. This study investigates the power density that can be obtained in PRO from such concentrated solutions. Thin-film composite membranes with an embedded woven mesh were supported by tricot fabric feed spacers in a specially designed crossflow cell to maximize the operating pressure of the system, reaching a stable applied hydraulic pressure of 48 bar (700 psi) for more than 10 h. Operation atmore » this increased hydraulic pressure allowed unprecedented power densities, up to 60 W/m(2) with a 3 M (180 g/L) NaCl draw solution. Experimental power densities demonstrate reasonable agreement with power densities modeled using measured membrane properties, indicating high-pressure operation does not drastically alter membrane performance. Our findings exhibit the promise of the generation of power from high-pressure PRO with concentrated solutions.« less

CFD Modeling of the Multipurpose Hydrogen Test Bed (MHTB) Self-Pressurization and Spray Bar Mixing Experiments in Normal Gravity: Effect of Accommodation Coefficient on the Tank Pressure

NASA Technical Reports Server (NTRS)

Kartuzova, Olga; Kassemi, Mohammad

2015-01-01

In this paper, a computational model that describes pressure control phase of a typical MHTB experiment will be presented. The fidelity of the model will be assessed by comparing the models predictions with MHTB experimental data. In this paper CFD results for MHTB spray bar cooling case with 50 tank fill ratio will be presented and analyzed. Effect of accommodation coefficient for calculating droplet-ullage mass transfer will be evaluated.

Report on FY15 Two-Bar Thermal Ratcheting Test Results

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

Wang, Yanli; Jetter, Robert I; Baird, Seth T

2015-06-22

Alloy 617 is a reference structural material for very high temperature components of advanced-gas cooled reactors with outlet temperatures in the range of . In order for designers to be able to use Alloy 617 for these high temperature components, Alloy 617 has to be approved for use in Section III (the nuclear section) of the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code. A plan has been developed to submit a draft code for Alloy 617 to ASME Section III by 2015. However, the current rules in Subsection NH* for the evaluation of strain limits andmore » creep-fatigue damage using simplified methods based on elastic analysis have been deemed inappropriate for Alloy 617 at temperatures above . The rationale for this exclusion is that at higher temperatures it is not feasible to decouple plasticity and creep deformation, which is the basis for the current simplified rules. This temperature, , is well below the temperature range of interest for this material in High Temperature Gas Cooled Reactor (HTGR) applications. The only current alternative is, thus, a full inelastic analysis which requires sophisticated material models which have been formulated but not yet verified. To address this issue, proposed code rules have been developed which are based on the use of elastic-perfectly plastic (EPP) analysis methods and which are expected to be applicable to very high temperatures. These newly proposed rules also address a long-term objective to provide an option for more simple, comprehensive and easily applied rules than the current so called simplified rules These two-bar tests discussed herein are part of an ongoing series of tests with cyclic loading at high temperatures using specimens representing key features of potential component designs. The initial focus of the two-bar ratcheting test program, to verify the procedure for evaluation of strain limits for Alloy 617 at very high temperatures, has been expanded to respond to

Effect of confining pressure due to external jacket of steel plate or shape memory alloy wire on bond behavior between concrete and steel reinforcing bars.

PubMed

Choi, Eunsoo; Kim, Dongkyun; Park, Kyoungsoo

2014-12-01

For external jackets of reinforced concrete columns, shape memory alloy (SMA) wires are easy to install, and they provide active and passive confining pressure; steel plates, on the other hand, only provide passive confining pressure, and their installation on concrete is not convenient because of the requirement of a special device. To investigate how SMA wires distinctly impact bond behavior compared with steel plates, this study conducted push-out bond tests of steel reinforcing bars embedded in concrete confined by SMA wires or steel plates. For this purpose, concrete cylinders were prepared with dimensions of 100 mm x 200 mm, and D-22 reinforcing bars were embedded at the center of the concrete cylinders. External jackets of 1.0 mm and 1.5 mm thickness steel plates were used to wrap the concrete cylinders. Additionally, NiTiNb SMA wire with a diameter of 1.0 mm was wound around the concrete cylinders. Slip of the reinforcing bars due to pushing force was measured by using a displacement transducer, while the circumferential deformation of specimens was obtained by using an extensometer. The circumferential deformation was used to calculate the circumferential strains of the specimens. This study assessed the radial confining pressure due to the external jackets on the reinforcing bars at bond strength from bond stress-slip curves and bond stress-circumferential strain curves. Then, the effects of the radial confining pressure on the bond behavior of concrete are investigated, and an equation is suggested to estimate bond strength using the radial confining pressure. Finally, this study focused on how active confining pressure due to recovery stress of the SMA wires influences bond behavior.

Solubility of carbon monoxide in n-hexane between 293 and 473 K and CO pressures up to 200 bar

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

Koelliker, R.; Thies, H.

The solubility of carbon monoxide, CO, in n-hexane was measured at 293, 323, 373, 423, and 473 K for CO partial pressures up to 200 bar. The enthalpy of solution was calculated between 293 and 473 K. Using the Krichevsky-Ilinskaya equation of state, the solubility of CO in n-hexane can be calculated between 293 and 423 K for CO partial pressures up to 200 bar with an accuracy better than 5%.

Testing of an actively damped boring bar featuring structurally integrated PZT stack actuators

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

Redmond, J.; Barney, P.

This paper summarizes the results of cutting tests performed using an actively damped boring bar to minimize chatter in metal cutting. A commercially available 2 inch diameter boring bar was modified to incorporate PZT stack actuators for controlling tool bending vibrations encountered during metal removal. The extensional motion of the actuators induce bending moments in the host structure through a two-point preloaded mounting scheme. Cutting tests performed at various speeds and depths of cuts on a hardened steel workpiece illustrate the bar`s effectiveness toward eliminating chatter vibrations and improving workpiece surface finish.

Testing the Effects of Helium Pressurant on Thermodynamic Vent System Performance with Liquid Hydrogen

NASA Technical Reports Server (NTRS)

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

2006-01-01

In support of the development of a zero gravity pressure control capability for liquid hydrogen, testing was conducted at the Marshall Space Flight Center using the Multipurpose Hydrogen Test Bed (MHTB) to evaluate the effects of helium pressurant on the performance of a spray bar thermodynamic vent system (TVS). Fourteen days of testing was performed in August - September 2005, with an ambient heat leak of about 70-80 watts and tank fill levels of 90%, 50%, and 25%. The TVS successfully controlled the tank pressure within a +/- 3.45 kPa (+/- 0.5 psi) band with various helium concentration levels in the ullage. Relative to pressure control with an "all hydrogen" ullage, the helium presence resulted in 10 to 30 per cent longer pressure reduction durations, depending on the fill level, during the mixing/venting phase of the control cycle. Additionally, the automated control cycle was based on mixing alone for pressure reduction until the pressure versus time slope became positive, at which time the Joule-Thomson vent was opened. Testing was also conducted to evaluate thermodynamic venting without the mixer operating, first with liquid then with vapor at the recirculation line inlet. Although ullage stratification was present, the ullage pressure was successfully controlled without the mixer operating. Thus, if vapor surrounded the pump inlet in a reduced gravity situation, the ullage pressure can still be controlled by venting through the TVS Joule Thomson valve and heat exchanger. It was evident that the spray bar configuration, which extends almost the entire length of the tank, enabled significant thermal energy removal from the ullage even without the mixer operating. Details regarding the test setup and procedures are presented in the paper. 1

Thermodynamic and related properties of oxygen from the triple point to 300 K at pressures to 1000 bar

NASA Technical Reports Server (NTRS)

Weber, L. A.

1977-01-01

The results of an experimental program are presented in the form of PVT data in the temperature range 58 to 300 K at pressures up to 800 bar. Tables of the derived thermodynamic properties on isobars to 1000 bar are given, including density, internal energy, enthalpy, entropy, specific heats at constant volume and constant pressure, velocity of sound, and the surface derivatives (delta P/delta T) sub rho and (delta P/delta Rho) sub T. Auxiliary tables in engineering units are also given. The accuracy of the data is discussed and comparisons are made with previous data.

On the feasibility to conduct gradient liquid chromatography separations in narrow-bore columns at pressures up to 2000bar.

PubMed

De Pauw, Ruben; Swier, Tim; Degreef, Bart; Desmet, Gert; Broeckhoven, Ken

2016-11-18

The limits in operating pressures are extended for narrow-bore columns in gradient elution up to 2000bar. As the required pumps for these pressures are incompatible with common chromatographic solvents and are not suitable to apply a mobile phase composition gradient, a mobile phase delivery and injection system is described and experimentally validated which allows to use any possible chromatographic solvent in isocratic and gradient elution. The mobile phase delivery and injection system also allows to perform multiple separations without the need to depressurize the column. This system consists out of 5 dual on/off valves and two large volume loops in which the gradient and equilibration volume of initial mobile phase are loaded by a commercial liquid chromatography pump. The loops are then flushed toward the column at extreme pressures. The mobile phase delivery and injection system is first evaluated in isocratic elution and shows a comparable performance to a state-of-the-art commercial flow-through-needle injector but with twice the pressure rating. Distortion of the loaded gradient by dispersion in the gradient storage loop is studied. The effect of the most important parameters (such as flow rate, pressure and gradient steepness) is experimentally investigated. Different gradient steepnesses and volumes can be applied at different flow rates and operating pressures with a good repeatability. Due to the isobaric operation of the pumps, the gradient is monitored in real-time by a mass flow meter installed at the detector outlet. The chromatograms are then converted from time to volume-base. A separation of a 19-compound sample is performed on a 300×2.1mm column at 1000bar and on a 600×2.1mm column at 2000bar. The peak capacity was found to increase from 141 to 199 and thus scales with L as is predicted by theory. This allows to conclude that the inlet pressure for narrow-bore columns in gradient elution can be increased up to 2000bar without fundamental

Liquid Methane Testing With a Large-Scale Spray Bar Thermodynamic Vent System

NASA Technical Reports Server (NTRS)

Hastings, L. J.; Bolshinskiy, L. G.; Hedayat, A.; Flachbart, R. H.; Sisco, J. D.; Schnell. A. R.

2014-01-01

NASA's Marshall Space Flight Center conducted liquid methane testing in November 2006 using the multipurpose hydrogen test bed outfitted with a spray bar thermodynamic vent system (TVS). The basic objective was to identify any unusual or unique thermodynamic characteristics associated with densified methane that should be considered in the design of space-based TVSs. Thirteen days of testing were performed with total tank heat loads ranging from 720 to 420 W at a fill level of approximately 90%. It was noted that as the fluid passed through the Joule-Thompson expansion, thermodynamic conditions consistent with the pervasive presence of metastability were indicated. This Technical Publication describes conditions that correspond with metastability and its detrimental effects on TVS performance. The observed conditions were primarily functions of methane densification and helium pressurization; therefore, assurance must be provided that metastable conditions have been circumvented in future applications of thermodynamic venting to in-space methane storage.

Monitoring Changes of Tropical Extreme Rainfall Events Using Differential Absorption Barometric Radar (DiBAR)

NASA Technical Reports Server (NTRS)

Lin, Bing; Harrah, Steven; Lawrence, R. Wes; Hu, Yongxiang; Min, Qilong

2015-01-01

This work studies the potential of monitoring changes in tropical extreme rainfall events such as tropical storms from space using a Differential-absorption BArometric Radar (DiBAR) operating at 50-55 gigahertz O2 absorption band to remotely measure sea surface air pressure. Air pressure is among the most important variables that affect atmospheric dynamics, and currently can only be measured by limited in-situ observations over oceans. Analyses show that with the proposed radar the errors in instantaneous (averaged) pressure estimates can be as low as approximately 5 millibars (approximately 1 millibar) under all weather conditions. With these sea level pressure measurements, the forecasts, analyses and understanding of these extreme events in both short and long time scales can be improved. Severe weathers, especially hurricanes, are listed as one of core areas that need improved observations and predictions in WCRP (World Climate Research Program) and NASA Decadal Survey (DS) and have major impacts on public safety and national security through disaster mitigation. Since the development of the DiBAR concept about a decade ago, our team has made substantial progress in advancing the concept. Our feasibility assessment clearly shows the potential of sea surface barometry using existing radar technologies. We have developed a DiBAR system design, fabricated a Prototype-DiBAR (P-DiBAR) for proof-of-concept, conducted lab, ground and airborne P-DiBAR tests. The flight test results are consistent with our instrumentation goals. Observational system simulation experiments for space DiBAR performance show substantial improvements in tropical storm predictions, not only for the hurricane track and position but also for the hurricane intensity. DiBAR measurements will lead us to an unprecedented level of the prediction and knowledge on tropical extreme rainfall weather and climate conditions.

An Electronic Pressure Profile Display system for aeronautic test facilities

NASA Technical Reports Server (NTRS)

Woike, Mark R.

1990-01-01

The NASA Lewis Research Center has installed an Electronic Pressure Profile Display system. This system provides for the real-time display of pressure readings on high resolution graphics monitors. The Electronic Pressure Profile Display system will replace manometer banks currently used in aeronautic test facilities. The Electronic Pressure Profile Display system consists of an industrial type Digital Pressure Transmitter (DPI) unit which interfaces with a host computer. The host computer collects the pressure data from the DPI unit, converts it into engineering units, and displays the readings on a high resolution graphics monitor in bar graph format. Software was developed to accomplish the above tasks and also draw facility diagrams as background information on the displays. Data transfer between host computer and DPT unit is done with serial communications. Up to 64 channels are displayed with one second update time. This paper describes the system configuration, its features, and its advantages over existing systems.

An electronic pressure profile display system for aeronautic test facilities

NASA Technical Reports Server (NTRS)

Woike, Mark R.

1990-01-01

The NASA Lewis Research Center has installed an Electronic Pressure Profile Display system. This system provides for the real-time display of pressure readings on high resolution graphics monitors. The Electronic Pressure Profile Display system will replace manometer banks currently used in aeronautic test facilities. The Electronic Pressure Profile Display system consists of an industrial type Digital Pressure Transmitter (DPT) unit which interfaces with a host computer. The host computer collects the pressure data from the DPT unit, converts it into engineering units, and displays the readings on a high resolution graphics monitor in bar graph format. Software was developed to accomplish the above tasks and also draw facility diagrams as background information on the displays. Data transfer between host computer and DPT unit is done with serial communications. Up to 64 channels are displayed with one second update time. This paper describes the system configuration, its features, and its advantages over existing systems.

Characterizing pressure issues due to turbulent flow in tubing, in ultra-fast chiral supercritical fluid chromatography at up to 580bar.

PubMed

Berger, Terry A

2016-12-02

It has been widely suggested that the outlet pressure be changed to maintain constant density ("isopycnic" conditions) when comparing the kinetic performance of different columns in supercritical fluid chromatography (SFC). However, at high flow rates, flow in the tubing is turbulent, causing large extra-column pressure drops that limit options for changing outlet pressure. Some of these pressure drops occur before and some after the column, obscuring the actual column inlet and outlet pressures. In this work, a 4.6×100mm, 1.8μm R,R-Whelk-O1 column was used with low dispersion LD (120μm) plumbing to generate sub-1min chiral separations. However, the optimum, or near optimum, flow rate was 5mL-min -1 , producing a system pressure of 580bar (with 40% methanol, outlet pressure 120bar). Both the flow rate and pump pressure required were near the limits of the instrument, and significantly exceeded the capability of many other SFC's. Extra-column pressure drops (ΔP ec ) were as high as 200bar, caused mostly by turbulent flow in the tubing. The ΔP ec increased by more than the square of the flow rate. Reynolds Numbers (Re) were calculated for tubing as a function of flow rate between 100 and 400bar and 5-20% methanol in CO 2 , and 40°-60°C. This represents the most extensive analysis of turbulence in tubing in the SFC literature. Flow in 120μm ID tubing was calculated to be laminar below 1.0mL-min -1 , mostly transitional up to 2.5mL-min -1 and virtually always turbulent at 3mL-min -1 and higher. Flow in 170μm tubing is turbulent at lower flows but generates half the ΔP ec due to the lower mobile phase linear velocity. The results suggest that, while sub-minute chromatograms are easily generated, 4.6mm columns are not very user friendly for use with sub-2μm packings. The high flow rates required just to reach optimum result in high ΔP ec generated by the tubing, causing uncertainty in the true column inlet, outlet, and average column pressure/density. When

Toilet Grab-Bar Preference and Center of Pressure Deviation During Toilet Transfers in Healthy Seniors, Seniors With Hip Replacements, and Seniors Having Suffered a Stroke.

PubMed

Kennedy, Matthew Joel; Arcelus, Amaya; Guitard, Paulette; Goubran, R A; Sveistrup, Heidi

2015-01-01

Multiple toilet grab-bar configurations are required by people with a diverse spectrum of disability. The study purpose was to determine toilet grab-bar preference of healthy seniors, seniors with a hip replacement, and seniors post-stroke, and to determine the effect of each configuration on centre of pressure (COP) displacement during toilet transfers. 14 healthy seniors, 7 ambulatory seniors with a hip replacement, and 8 ambulatory seniors post-stroke participated in the study. Toilet transfers were performed with no bars (NB), commode (C), two vertical bars (2VB), one vertical bar (1VB), a horizontal bar (H), two swing-away bars (S) and a diagonal bar (D). COP was measured using pressure sensitive floor mats. Participants rated the safety, ease of use, helpfulness, comfort and preference for instalment. 2VB was most preferred and had the smallest COP deviation. Least preferred was H and NB. C caused largest COP displacement but had favourable ratings. The preference and safety of the 2VB should be considered in the design of accessible toilets and in accessibility construction guidelines. However these results need to be verified in non-ambulatory populations. C is frequently prescribed, but generates large COP deviation, suggesting it may present an increased risk of falls.

Parker Solar Probe Light Bar Test

NASA Image and Video Library

2018-06-05

In the Astrotech processing facility in Titusville, Florida, near NASA's Kennedy Space Center, on Tuesday, June 5, 2018, technicians and engineers perform light bar testing on NASA's Parker Solar Probe. The Parker Solar Probe will launch on a United Launch Alliance Delta IV Heavy rocket from Space Launch Complex 37 at Cape Canaveral Air Force Station in Florida no earlier than Aug. 4, 2018. The mission will perform the closest-ever observations of a star when it travels through the Sun's atmosphere, called the corona. The probe will rely on measurements and imaging to revolutionize our understanding of the corona and the Sun-Earth connection.

Dynamic behavior of geometrically complex hybrid composite samples in a Split-Hopkinson Pressure Bar system

NASA Astrophysics Data System (ADS)

Pouya, M.; Balasubramaniam, S.; Sharafiev, S.; F-X Wagner, M.

2018-06-01

The interfaces between layered materials play an important role for the overall mechanical behavior of hybrid composites, particularly during dynamic loading. Moreover, in complex-shaped composites, interfacial failure is strongly affected by the geometry and size of these contact interfaces. As preliminary work for the design of a novel sample geometry that allows to analyze wave reflection phenomena at the interfaces of such materials, a series of experiments using a Split-Hopkinson Pressure Bar technique was performed on five different sample geometries made of a monomaterial steel. A complementary explicit finite element model of the Split-Hopkinson Pressure Bar system was developed and the same sample geometries were studied numerically. The simulated input, reflected and transmitted elastic wave pulses were analyzed for the different sample geometries and were found to agree well with the experimental results. Additional simulations using different composite layers of steel and aluminum (with the same sample geometries) were performed to investigate the effect of material variation on the propagated wave pulses. The numerical results show that the reflected and transmitted wave pulses systematically depend on the sample geometry, and that elastic wave pulse propagation is affected by the properties of individual material layers.

Active Sensing Air Pressure Using Differential Absorption Barometric Radar

NASA Astrophysics Data System (ADS)

Lin, B.

2016-12-01

Tropical storms and other severe weathers cause huge life losses and property damages and have major impacts on public safety and national security. Their observations and predictions need to be significantly improved. This effort tries to develop a feasible active microwave approach that measures surface air pressure, especially over open seas, from space using a Differential-absorption BArometric Radar (DiBAR) operating at 50-55 GHz O2 absorption band in order to constrain assimilated dynamic fields of numerical weather Prediction (NWP) models close to actual conditions. Air pressure is the most important variable that drives atmospheric dynamics, and currently can only be measured by limited in-situ observations over oceans. Even over land there is no uniform coverage of surface air pressure measurements. Analyses show that with the proposed space radar the errors in instantaneous (averaged) pressure estimates can be as low as 4mb ( 1mb) under all weather conditions. NASA Langley research team has made substantial progresses in advancing the DiBAR concept. The feasibility assessment clearly shows the potential of surface barometry using existing radar technologies. The team has also developed a DiBAR system design, fabricated a Prototype-DiBAR (P-DiBAR) for proof-of-concept, conducted laboratory, ground and airborne P-DiBAR tests. The flight test results are consistent with the instrumentation goals. The precision and accuracy of radar surface pressure measurements are within the range of the theoretical analysis of the DiBAR concept. Observational system simulation experiments for space DiBAR performance based on the existing DiBAR technology and capability show substantial improvements in tropical storm predictions, not only for the hurricane track and position but also for the hurricane intensity. DiBAR measurements will provide us an unprecedented level of the prediction and knowledge on global extreme weather and climate conditions.

High Pressure Steam Oxidation of Alloys for Advanced Ultra-Supercritical Conditions

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

Holcomb, Gordon R.

A steam oxidation test was conducted at 267 ± 17 bar and 670°C for 293 hr. A comparison test was run at 1 bar. All of the alloys showed an increase in scale thickness and oxidation rate with pressure, and TP304H and IN625 had very large increases. Fine-grained TP304H at 267 bar behaved like a coarse grained alloy, indicative of high pressure increasing the critical Cr level needed to form and maintain a chromia scale. At 267 bar H230, H263, H282, IN617 and IN740 had kp values a factor of one–to-two orders of magnitude higher than at 1 bar. IN625more » had a four order of magnitude increase in kp at 267 bar compared to 1 bar. Possible causes for increased oxidation rates with increased pressure were examined, including increased solid state diffusion within the oxide scale and increased critical Cr content to establish and maintain a chromia scale.« less

8. Photocopied August 1978. BREAKING CONCRETE BARS, JULY 1898. TESTING ...

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

8. Photocopied August 1978. BREAKING CONCRETE BARS, JULY 1898. TESTING MACHINE USED BY VON SCHON IN EXPERIMENTS ON METHODS OF MIXING CONCRETE AND ON CONCRETE AGGREGATES WHICH USED LOCAL MATERIALS. (4) - Michigan Lake Superior Power Company, Portage Street, Sault Ste. Marie, Chippewa County, MI

Surface Fatigue Tests Of M50NiL Gears And Bars

NASA Technical Reports Server (NTRS)

Townsend, Dennis P.; Bamberger, Eric N.

1994-01-01

Report presents results of tests of steels for use in gears and bearings of advanced aircraft. Spur-gear endurance tests and rolling-element surface fatigue tests performed on gear and bar specimens of M50NiL steel processed by vacuum induction melting and vacuum arc remelting (VIM-VAR). Compares results of tests with similar tests of specimens of VIM-VAR AISI 9310 steel and of AISI 9310 steel subjected to VAR only.

Combined Hyperbaric Oxygen Partial Pressure at 1.4 Bar with Infrared Radiation: A Useful Tool To Improve Tissue Hypoxemia?

PubMed

Dünnwald, Tobias; Held, Julia; Balan, Petru; Pecher, Otto; Zeiger, Thomas; Hartig, Frank; Mur, Erich; Weiss, Günter; Schobersberger, Wolfgang

2018-06-13

Tissue hypoxia contributes to the pathogenesis of several acute and chronic diseases. Hyperbaric oxygen therapy (HBO) and whole-body warming using low-temperature infrared technology (LIT) are techniques that might improve hypoxemia. Combining HBO and LIT as hyperbaric oxygen therapy combined with low-temperature infrared radiation (HBOIR) might be an approach that results in positive synergistic effects on oxygenation. LIT increases blood flow and could reduce HBO-induced vasoconstriction, and hyperoxia could compensate for the increased metabolic oxygen requirements mediated by LIT. Both LIT and HBO increase the oxygen diffusion distance in the tissues. HBOIR at 0.5 bar has been shown to be safe and feasible. However, physiological responses and the safety of HBOIR at an increased oxygen (O2) partial pressure of 1.4 bar or 2.4 atmospheres absolute (ATA) still need to be determined. The hope is that should HBOIR at an increased oxygen partial pressure of 1.4 bar be safe, future studies to examine its efficacy in patients with clinical conditions, which include peripheral arterial disease (PAD) or wound healing disorders, will follow. The results of pilot studies have shown that HBOIR at an overload pressure is safe and well tolerated in healthy participants but can generate moderate cardiovascular changes and an increase in body temperature. From the findings of this pilot study, due to its potential synergistic effects, HBOIR could be a promising tool for the treatment of human diseases associated with hypoxemia.

Selective versus routine patch metal allergy testing to select bar material for the Nuss procedure in 932 patients over 10years.

PubMed

Obermeyer, Robert J; Gaffar, Sheema; Kelly, Robert E; Kuhn, M Ann; Frantz, Frazier W; McGuire, Margaret M; Paulson, James F; Kelly, Cynthia S

2018-02-01

The aim of the study was to determine the role of patch metal allergy testing to select bar material for the Nuss procedure. An IRB-approved (11-04-WC-0098) single institution retrospective, cohort study comparing selective versus routine patch metal allergy testing to select stainless steel or titanium bars for Nuss repair was performed. In Cohort A (9/2004-1/2011), selective patch testing was performed based on clinical risk factors. In Cohort B (2/2011-9/2014), all patients were patch tested. The cohorts were compared for incidence of bar allergy and resultant premature bar loss. Risk factors for stainless steel allergy or positive patch test were evaluated. Cohort A had 628 patients with 63 (10.0%) selected for patch testing, while all 304 patients in Cohort B were tested. Over 10years, 15 (1.8%) of the 842 stainless steel Nuss repairs resulted in a bar allergy, and 5 had a negative preoperative patch test. The incidence of stainless steel bar allergy (1.8% vs 1.7%, p=0.57) and resultant bar loss (0.5% vs 1.3%, p=0.23) was not statistically different between cohorts. An allergic reaction to a stainless steel bar or a positive patch test was more common in females (OR=2.3, p<0.001) and patients with a personal (OR=24.8, p<0.001) or family history (OR=3.1, p<0.001) of metal sensitivity. Stainless steel bar allergies occur at a low incidence with either routine or selective patch metal allergy testing. If selective testing is performed, it is advisable in females and patients with a personal or family history of metal sensitivity. A negative preoperative patch metal allergy test does not preclude the possibility of a postoperative stainless steel bar allergy. Level III Treatment Study and Study of Diagnostic Test. Copyright © 2017 Elsevier Inc. All rights reserved.

CFD Modeling of the Multipurpose Hydrogen Test Bed (MHTB) Self-Pressurization and Spray Bar Mixing Experiments in Normal Gravity: Effect of the Accommodation Coefficient on the Tank Pressure

NASA Technical Reports Server (NTRS)

Kartuzova, Olga; Kassemi, Mohammad

2015-01-01

A CFD model for simulating the self-pressurization of a large scale liquid hydrogen storage tank is utilized in this paper to model the MHTB self-pressurization experiment. The kinetics-based Schrage equation is used to account for the evaporative and condensi ng interfacial mass flows in this model. The effect of the accommodation coefficient for calculating the interfacial mass transfer rate on the tank pressure during tank selfpressurization is studied. The values of the accommodation coefficient which were considered in this study vary from 1.0e-3 to 1.0e-1 for the explicit VOF model and from 1.0e-4 to 1.0e-3 for the implicit VOF model. The ullage pressure evolutions are compared against experimental data. A CFD model for controlling pressure in cryogenic storage tanks by spraying cold liquid into the ullage is also presented. The Euler-Lagrange approach is utilized for tracking the spray droplets and for modeling the interaction between the droplets and the continuous phase (ullage). The spray model is coupled with the VOF model by performing particle tracking in the ullage, removing particles from the ullage when they reach the interface, and then adding their contributions to the liquid. Droplet-ullage heat and mass transfer are modeled. The flow, temperature, and interfacial mass flux, as well as droplets trajectories, size distribution and temperatures predicted by the model are presented. The ul lage pressure and vapor temperature evolutions are compared with experimental data obtained from the MHTB spray bar mixing experiment. The effect of the accommodation coefficient for calculating the interfacial and droplet mass transfer rates on the tank pressure during mixing of the vapor using spray is studied. The values used for the accommodation coefficient at the interface vary from 1.0e-5 to 1.0e-2. The droplet accommodation coefficient values vary from 2.0e-6 to 1.0e-4.

High-strain rate tensile characterization of graphite platelet reinforced vinyl ester based nanocomposites using split-Hopkinson pressure bar

NASA Astrophysics Data System (ADS)

Pramanik, Brahmananda

The dynamic response of exfoliated graphite nanoplatelet (xGnP) reinforced and carboxyl terminated butadiene nitrile (CTBN) toughened vinyl ester based nanocomposites are characterized under both dynamic tensile and compressive loading. Dynamic direct tensile tests are performed applying the reverse impact Split Hopkinson Pressure Bar (SHPB) technique. The specimen geometry for tensile test is parametrically optimized by Finite Element Analysis (FEA) using ANSYS Mechanical APDLRTM. Uniform stress distribution within the specimen gage length has been verified using high-speed digital photography. The on-specimen strain gage installation is substituted by a non-contact Laser Occlusion Expansion Gage (LOEG) technique for infinitesimal dynamic tensile strain measurements. Due to very low transmitted pulse signal, an alternative approach based on incident pulse is applied for obtaining the stress-time history. Indirect tensile tests are also performed combining the conventional SHPB technique with Brazilian disk test method for evaluating cylindrical disk specimens. The cylindrical disk specimen is held snugly in between two concave end fixtures attached to the incident and transmission bars. Indirect tensile stress is estimated from the SHPB pulses, and diametrical transverse tensile strain is measured using LOEG. Failure diagnosis using high-speed digital photography validates the viability of utilizing this indirect test method for characterizing the tensile properties of the candidate vinyl ester based nanocomposite system. Also, quasi-static indirect tensile response agrees with previous investigations conducted using the traditional dog-bone specimen in quasi-static direct tensile tests. Investigation of both quasi-static and dynamic indirect tensile test responses show the strain rate effect on the tensile strength and energy absorbing capacity of the candidate materials. Finally, the conventional compressive SHPB tests are performed. It is observed that both

Air jet erosion test on plasma sprayed surface by varying erodent impingement pressure and impingement angle

NASA Astrophysics Data System (ADS)

Behera, Ajit; Behera, Asit; Mishra, S. C.; Pani, S.; Parida, P.

2015-02-01

Fly-ash premixed with quartz and illmenite powder in different weight proportions are thermal sprayed on mild steel and copper substrates at various input power levels of the plasma torch ranging from 11 kW to 21 kW DC. The erosion test has done using Air Jet erosion test Reg (As per ASTM G76) with silica erodent typically 150-250 pm in size. Multiple tests were performed at increasing the time duration from 60 sec to 180 sec with increasing pressure (from 1 bar to 2.5 bar) and angle (60° & 90°). This study reveals that the impact velocity and impact angle are two most significant parameters among various factors influencing the wear rate of these coatings. The mechanisms and microstructural changes that arise during erosion wear are studied by using SEM. It is found that, when erodent are impacting the fresh un-eroded surface, material removal occurs by the continuous evolution of craters on the surface. Upper layer splats are removed out after 60 sec and second layer splat erosion starts. Based on these observations Physical models are developed. Some graphs plotted between mass loss-rate versus time period/impact Pressure/impact Angle gives good correlation with surface features observed.

Thermodynamic Vent System Performance Testing with Subcooled Liquid Methane and Gaseous Helium Pressurant

NASA Technical Reports Server (NTRS)

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

2007-01-01

Due to its high specific impulse and favorable thermal properties for storage, liquid methane (LCH4) is being considered as a candidate propellant for exploration architectures. In order to gain an -understanding of any unique considerations involving micro-gravity pressure control with LCH4, testing was conducted at the Marshall Space Flight Center using the Multipurpose Hydrogen Test Bed (MHTB) to evaluate the performance of a spray-bar thermodynamic vent system (TVS) with subcooled LCH4 and gaseous helium (GHe) pressurant. Thirteen days of testing were performed in November 2006, with total tank heat leak conditions of about 715 W and 420 W at a fill level of approximately 90%. The TVS system was used to subcool the LCH4 to a liquid saturation pressure of approximately 55.2 kPa before the tank was pressurized with GHe to a total pressure of 165.5 kPa. A total of 23 TVS cycles were completed. The TVS successfully controlled the ullage pressure within a prescribed control band but did not maintain a stable liquid saturation pressure. This was likely. due to a TVS design not optimized for this particular propellant and test conditions, and possibly due to a large artificially induced heat input directly into the liquid. The capability to reduce liquid saturation pressure as well as maintain it within a prescribed control band, demonstrated that the TVS could be used to seek and maintain a desired liquid inlet temperature for an engine (at a cost of propellant lost through the TVS vent). One special test was conducted at the conclusion of the planned test activities. Reduction of the tank ullage pressure by opening the Joule-Thomson valve (JT) without operating the pump was attempted. The JT remained open for over 9300 seconds, resulting in an ullage pressure reduction of 30 kPa. The special test demonstrated the feasibility of using the JT valve for limited ullage pressure reduction in the event of a pump failure.

Transient Pressure Test Article Test Program

NASA Technical Reports Server (NTRS)

Vibbart, Charles M.

1989-01-01

The Transient Pressure Test Article (TPTA) test program is being conducted at a new test facility located in the East Test Area at the National Aeronautics and Space Administration's (NASA's) Marshall Space Flight Center (MSFC) in Huntsville, Alabama. This facility, along with the special test equipment (STE) required for facility support, was constructed specifically to test and verify the sealing capability of the Redesigned Solid Rocket Motor (RSRM) field, igniter, and nozzle joints. The test article consists of full scale RSRM hardware loaded with inert propellant and assembled in a short stack configuration. The TPTA is pressurized by igniting a propellant cartridge capable of inducing a pressure rise rate which stimulates the ignition transient that occurs during launch. Dynamic loads are applied during the pressure cycle to simulate external tank attach (ETA) strut loads present on the ETA ring. Sealing ability of the redesigned joints is evaluated under joint movement conditions produced by these combined loads since joint sealing ability depends on seal resilience velocity being greater than gap opening velocity. Also, maximum flight dynamic loads are applied to the test article which is either pressurized to 600 psia using gaseous nitrogen (GN2) or applied to the test article as the pressure decays inside the test article on the down cycle after the ignition transient cycle. This new test facility is examined with respect to its capabilities. In addition, both the topic of test effectiveness versus space vehicle flight performance and new aerospace test techniques, as well as a comparison between the old SRM design and the RSRM are presented.

Optimization of Pressurized Oxy-Combustion with Flameless Reactor

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

Malavasi, Massimo; Landegger, Gregory

2014-06-30

Pressurized OxyECombustion is one of the most promising technologies for utility-scale power generation plants. Benefits include the ability to burn low rank coal and capture CO 2. By increasing the flue gas pressure during this process, greater efficiencies are derived from increased quantity and quality of thermal energy recovery. UPA with modeling support from MIT and testing and data verification by Georgia Tech’s Research Center designed and built a 100 kW system capable of demonstrating pressurized oxyEcombustion using a flameless combustor. Wyoming PRB coal was run at 15 and 32 bar. Additional tests were not completed but sampled data demonstratedmore » the viability of the technology over a broader range of operating pressures, Modeling results illustrated a flat efficiency curve over 20 bar, with optimum efficiency achieved at 29 bar. This resulted in a 33% (HHV) efficiency, a 5 points increase in efficiency versus atmospheric oxy-combustion, and a competitive cost of electricity plus greater CO 2 avoidance costs then prior study’s presented. UPA’s operation of the bench-scale system provided evidence that key performance targets were achieved: flue gas sampled at the combustor outlet had non-detectable residual fly ashes, and low levels of SO3 and heavy-metal. These results correspond to prior pressurized oxy-combustion testing completed by IteaEEnel.« less

Validation testing of shallow notched round-bar screening test specimens. [for the space shuttle main engine

NASA Technical Reports Server (NTRS)

Vroman, G. A.

1975-01-01

The capability of shallow-notched, round-bar, tensile specimens for screening critical environments as they affect the material fracture properties of the space shuttle main engine was tested and analyzed. Specimens containing a 0.050-inch-deep circumferential sharp notch were cyclically loaded in a 5000-psi hydrogen environment at temperatures of +70 and -15 F. Replication of test results and a marked change in cyclic life because of temperature variation demonstrated the validity of the specimen type to be utilized for screening tests.

Mechanical testing of a steel-reinforced epoxy resin bar and clamp for external skeletal fixation of long-bone fractures in cats.

PubMed

Leitch, B J; Worth, A J

2018-05-01

To provide veterinarians with confidence when using a commercially available epoxy resin in external skeletal fixators (ESF), testing was conducted to determine exothermia during curing of the epoxy resin compared to polymethylmethacrylate (PMMA), the hardness of the epoxy resin as a bar over 16 weeks, and the strength of the epoxy resin bar compared with metal clamps in similarly constructed Type 1a ESF constructs simulating the repair of feline long bone fractures. Exothermia of the epoxy resin during curing was tested against PMMA with surface temperatures recorded over the first 15 minutes of curing, using four samples of each product. The hardness of 90 identical epoxy resin bars was tested by subjecting them to cyclic loads (1,000 cycles of 20.5 N, every 7 days) over a 16-week period and impact testing 10 bars every 2 weeks. Ten bars that were not subjected to cyclic loads were impact tested at 0 weeks and another 10 at 16 weeks. Strength of the epoxy resin product, as a bar and clamp composite, was tested against metal SK and Kirschner-Ehmer (KE) clamps and bars in Type 1a, tied-in intramedullary pin, ESF constructs with either 90° or 75° pin placement, subjected to compressive and bending loads to 75 N. The maximum temperature during curing of the epoxy resin (min 39.8, max 43.0)°C was less than the PMMA (min 85.2, max 98.5)°C (p<0.001). There was no change in hardness of the epoxy resin bars over the 16 weeks of cyclic loading (p=0.58). There were no differences between the median strength of the epoxy resin, SK or KE ESF constructs in compression or bending when tested to 75 N (p>0.05). Stiffness of constructs with 75° pin placement was greater for SK than epoxy resin constructs in compression (p=0.046), and was greater for KE than epoxy resin constructs in bending (p=0.033). The epoxy resin tested was found to be less exothermic than PMMA; bars made from the epoxy resin showed durability over an expected fracture healing timeframe and had

Simulation of Watts Bar Unit 1 Initial Startup Tests with Continuous Energy Monte Carlo Methods

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

Godfrey, Andrew T; Gehin, Jess C; Bekar, Kursat B

2014-01-01

The Consortium for Advanced Simulation of Light Water Reactors* is developing a collection of methods and software products known as VERA, the Virtual Environment for Reactor Applications. One component of the testing and validation plan for VERA is comparison of neutronics results to a set of continuous energy Monte Carlo solutions for a range of pressurized water reactor geometries using the SCALE component KENO-VI developed by Oak Ridge National Laboratory. Recent improvements in data, methods, and parallelism have enabled KENO, previously utilized predominately as a criticality safety code, to demonstrate excellent capability and performance for reactor physics applications. The highlymore » detailed and rigorous KENO solutions provide a reliable nu-meric reference for VERAneutronics and also demonstrate the most accurate predictions achievable by modeling and simulations tools for comparison to operating plant data. This paper demonstrates the performance of KENO-VI for the Watts Bar Unit 1 Cycle 1 zero power physics tests, including reactor criticality, control rod worths, and isothermal temperature coefficients.« less

A Modified Split Hopkinson Pressure Bar Approach for Mimicking Dynamic Oscillatory Stress Fluctuations During Earthquake Rupture

NASA Astrophysics Data System (ADS)

Braunagel, M. J.; Griffith, W. A.

2017-12-01

Past experimental work has demonstrated that rock failure at high strain rates occurs by fragmentation rather than discrete fracture and is accompanied by a dramatic increase in rock strength. However, these observations are difficult to reconcile with the assertion that pulverized rocks in fault zones are the product of impulsive stresses during the passage of earthquake ruptures, as the distance from the principal slip zones of some pulverized rock is too great to exceed fragmentation transition. One potential explanation to this paradox that has been suggested is that repeated loading over the course of multiple earthquake ruptures may gradually reduce the pulverization threshold, in terms of both strain rate and strength. We propose that oscillatory loading during a single earthquake rupture may further lower these pulverization thresholds, and that traditional dynamic experimental approaches, such as the Split Hopkinson Pressure Bar (SHPB) wherein load is applied as a single, smooth, sinusoidal compressive wave, may not reflect natural loading conditions. To investigate the effects of oscillatory compressive loading expected during earthquake rupture propagation, we develop a controlled cyclic loading model on a SHPB apparatus utilizing two striker bars connected by an elastic spring. Unlike traditional SHPB experiments that utilize a gas gun to fire a projectile bar and generate a single compressive wave on impact with the incident bar, our modified striker bar assembly oscillates while moving down the gun barrel and generates two separate compressive pulses separated by a lag time. By modeling the modified assembly as a mass-spring-mass assembly accelerating due to the force of the released gas, we can predict the compression time of the spring upon impact and therefore the time delay between the generation of the first and second compressive waves. This allows us to predictably control load cycles with durations of only a few hundred microseconds. Initial

Telescoping magnetic ball bar test gage

DOEpatents

Bryan, J.B.

1984-03-13

A telescoping magnetic ball bar test gage for determining the accuracy of machine tools, including robots, and those measuring machines having non-disengageable servo drives which cannot be clutched out is disclosed. Two gage balls are held and separated from one another by a telescoping fixture which allows them relative radial motional freedom but not relative lateral motional freedom. The telescoping fixture comprises a parallel reed flexure unit and a rigid member. One gage ball is secured by a magnetic socket knuckle assembly which fixes its center with respect to the machine being tested. The other gage ball is secured by another magnetic socket knuckle assembly which is engaged or held by the machine in such manner that the center of that ball is directed to execute a prescribed trajectory, all points of which are equidistant from the center of the fixed gage ball. As the moving ball executes its trajectory, changes in the radial distance between the centers of the two balls caused by inaccuracies in the machine are determined or measured by a linear variable differential transformer (LVDT) assembly actuated by the parallel reed flexure unit. Measurements can be quickly and easily taken for multiple trajectories about several different fixed ball locations, thereby determining the accuracy of the machine. 3 figs.

Telescoping magnetic ball bar test gage

DOEpatents

Bryan, J.B.

1982-03-15

A telescoping magnetic ball bar test gage for determining the accuracy of machine tools, including robots, and those measuring machines having non-disengagable servo drives which cannot be clutched out. Two gage balls are held and separated from one another by a telescoping fixture which allows them relative radial motional freedom but not relative lateral motional freedom. The telescoping fixture comprises a parallel reed flexure unit and a rigid member. One gage ball is secured by a magnetic socket knuckle assembly which fixes its center with respect to the machine being tested. The other gage ball is secured by another magnetic socket knuckle assembly which is engaged or held by the machine in such manner that the center of that ball is directed to execute a prescribed trajectory, all points of which are equidistant from the center of the fixed gage ball. As the moving ball executes its trajectory, changes in the radial distance between the centers of the two balls caused by inaccuracies in the machine are determined or measured by a linear variable differential transformer (LVDT) assembly actuated by the parallel reed flexure unit. Measurements can be quickly and easily taken for multiple trajectories about several different fixed ball locations, thereby determining the accuracy of the machine.

Effect of pressure and shielding gas on the microstructure of hyperbaric metal cored GMAW welds down to 111 bar

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

Jorge, J.C.F.; Santos, V.R. dos; Santos, J.F. dos

1995-12-31

The microstructural evolution of hyperbaric C-Mn weld metals was studied by means of bead-on-plate welds deposit with GMAW process using a commercial metal cored wire. The welding was carried out in the flat position in the range of 51 bar to 111 bar with He+ CO{sub 2} as shielding gas, which CO{sub 2} content varied from 0.1% to 0.8 %. The microstructures were quantitatively analyzed by optical microscopy to evaluate the amount of constituents according to the IIW/IIS terminology. The results showed that all weld metals presented great amounts of acicular ferrite and a stronger influence of pressure on microstructuremore » compared to the influence of the shielding gas.« less

Fatigue of reinforcing bars during hydro-demolition

NASA Astrophysics Data System (ADS)

Hyland, C. W. K.; Ouwejan, A.

2017-05-01

Reinforcing steel fractured during hydro-demolition of a reinforced concrete pier head due to low cycle flexural fatigue from vibration caused by impact of the high pressure water jet on the exposed length of the bars. Research into the fatigue performance of steel reinforcing steel tends to focus on the high cycle axial performance in reinforced concrete members and re-bending behaviour. However with the increasing use of hydro-demolition of concrete structures as part of remediation works care is required to ensure the steel reinforcement exposed to the high pressure jet of water is not going to suffer relatively low cycle flexural damage that may compromise the designed performance of the completed reinforced concrete structure. This paper describes the failure assessment, fatigue analysis, and metallographic examination that was undertaken. It was found that the rib to flank transition radius on the reinforcement steel was small enough to cause a significant stress concentration effect and was the location of fatigue crack growth. A relatively simple analysis using the maximum unrestrained cantilevered bar length and force exerted by the water jet was used to calculate the maximum expected bending moment. This was compared to the bending capacity at initiation of yielding at the rib flank transition accounting for stress concentration effects. This showed that the observed cyclic reversing ductile crack growth and fracture of the H25 bars was consistent with the loading applied. A method is proposed based on these observations to assess suitable limits for unrestrained bar lengths or maximum working offset of the water jet from the point of bar restraint when undertaking hydro-demolition work. The fatigue critical performance requirements of AS/NZS4671 500E bars are also therefore compared with those of BS4449:2005 and PN EN/ISO 15630-1:2011 for comparable 500C bars

Pressure-Application Device for Testing Pressure Sensors

NASA Technical Reports Server (NTRS)

2002-01-01

A portable pressure-application device has been designed and built for use in testing and calibrating piezoelectric pressure transducers in the field. The device generates pressure pulses of known amplitude. A pressure pulse (in contradistinction to a steady pressure) is needed because in the presence of a steady pressure, the electrical output of a piezoelectric pressure transducer decays rapidly with time. The device includes a stainless- steel compressed-air-storage cylinder of 500 cu cm volume. A manual hand pump with check valves and a pressure gauge are located at one end of the cylinder. A three-way solenoid valve that controls the release of pressurized air is located at the other end of the cylinder. Power for the device is provided by a 3.7-V cordless-telephone battery. The valve is controlled by means of a pushbutton switch, which activates a 5 V to +/-15 V DC-to-DC converter that powers the solenoid. The outlet of the solenoid valve is connected to the pressure transducer to be tested. Before the solenoid is energized, the transducer to be tested is at atmospheric pressure. When the solenoid is actuated by the push button, pressurized air from inside the cylinder is applied to the transducer. Once the pushbutton is released, the cylinder pressure is removed from the transducer and the pressurized air applied to the transducer is vented, bringing the transducer back to atmospheric pressure. Before this device was used for actual calibration, its accuracy was checked with a NIST (National Institute of Standards and Technology) traceable calibrator and commercially calibrated pressure transducers. This work was done by Wanda Solano of Stennis Space Center and Greg Richardson of Lockheed Martin Corp.

A novel automated rat catalepsy bar test system based on a RISC microcontroller.

PubMed

Alvarez-Cervera, Fernando J; Villanueva-Toledo, Jairo; Moo-Puc, Rosa E; Heredia-López, Francisco J; Alvarez-Cervera, Margarita; Pineda, Juan C; Góngora-Alfaro, José L

2005-07-15

Catalepsy tests performed in rodents treated with drugs that interfere with dopaminergic transmission have been widely used for the screening of drugs with therapeutic potential in the treatment of Parkinson's disease. The basic method for measuring catalepsy intensity is the "standard" bar test. We present here an easy to use microcontroller-based automatic system for recording bar test experiments. The design is simple, compact, and has a low cost. Recording intervals and total experimental time can be programmed within a wide range of values. The resulting catalepsy times are stored, and up to five simultaneous experiments can be recorded. A standard personal computer interface is included. The automated system also permits the elimination of human error associated with factors such as fatigue, distraction, and data transcription, occurring during manual recording. Furthermore, a uniform criterion for timing the cataleptic condition can be achieved. Correlation values between the results obtained with the automated system and those reported by two independent observers ranged between 0.88 and 0.99 (P<0.0001; three treatments, nine animals, 144 catalepsy time measurements).

49 CFR 195.304 - Test pressure.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 49 Transportation 3 2013-10-01 2013-10-01 false Test pressure. 195.304 Section 195.304... PIPELINE Pressure Testing § 195.304 Test pressure. The test pressure for each pressure test conducted under... case of a pipeline that is not visually inspected for leakage during the test, for at least an...

49 CFR 195.304 - Test pressure.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 49 Transportation 3 2012-10-01 2012-10-01 false Test pressure. 195.304 Section 195.304... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) PIPELINE SAFETY TRANSPORTATION OF HAZARDOUS LIQUIDS BY PIPELINE Pressure Testing § 195.304 Test pressure. The test pressure for each pressure test conducted under...

49 CFR 195.304 - Test pressure.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 49 Transportation 3 2010-10-01 2010-10-01 false Test pressure. 195.304 Section 195.304... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) PIPELINE SAFETY TRANSPORTATION OF HAZARDOUS LIQUIDS BY PIPELINE Pressure Testing § 195.304 Test pressure. The test pressure for each pressure test conducted under...

49 CFR 195.304 - Test pressure.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 49 Transportation 3 2011-10-01 2011-10-01 false Test pressure. 195.304 Section 195.304... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) PIPELINE SAFETY TRANSPORTATION OF HAZARDOUS LIQUIDS BY PIPELINE Pressure Testing § 195.304 Test pressure. The test pressure for each pressure test conducted under...

49 CFR 195.304 - Test pressure.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 49 Transportation 3 2014-10-01 2014-10-01 false Test pressure. 195.304 Section 195.304... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) PIPELINE SAFETY TRANSPORTATION OF HAZARDOUS LIQUIDS BY PIPELINE Pressure Testing § 195.304 Test pressure. The test pressure for each pressure test conducted under...

Spray Bar Zero-Gravity Vent System for On-Orbit Liquid Hydrogen Storage

NASA Technical Reports Server (NTRS)

Hastings, L. J.; Flachbart, R. H.; Martin, J. J.; Hedayat, A.; Fazah, M.; Lak, T.; Nguyen, H.; Bailey, J. W.

2003-01-01

During zero-gravity orbital cryogenic propulsion operations, a thermodynamic vent system (TVS) concept is expected to maintain tank pressure control without propellant resettling. In this case, a longitudinal spray bar mixer system, coupled with a Joule-Thompson (J-T) valve and heat exchanger, was evaluated in a series of TVS tests using the 18 cu m multipurpose hydrogen test bed. Tests performed at fill levels of 90, 50, and 25 percent, coupled with heat tank leaks of about 20 and 50 W, successfully demonstrated tank pressure control within a 7-kPa band. Based on limited testing, the presence of helium constrained the energy exchange between the gaseous and liquid hydrogen (LH2) during the mixing cycles. A transient analytical model, formulated to characterize TVS performance, was used to correlate the test data. During self-pressurization cycles following tank lockup, the model predicted faster pressure rise rates than were measured; however, once the system entered the cyclic self-pressurization/mixing/venting operational mode, the modeled and measured data were quite similar. During a special test at the 25-percent fill level, the J-T valve was allowed to remain open and successfully reduced the bulk LH2 saturation pressure from 133 to 70 kPa in 188 min.

Bar dimensions and bar shapes in estuaries

NASA Astrophysics Data System (ADS)

Leuven, Jasper; Kleinhans, Maarten; Weisscher, Steven; van der Vegt, Maarten

2016-04-01

Estuaries cause fascinating patterns of dynamic channels and shoals. Intertidal sandbars are valuable habitats, whilst channels provide access to harbors. We still lack a full explanation and classification scheme for the shapes and dimensions of bar patterns in natural estuaries, in contrast with bars in rivers. Analytical physics-based models suggest that bar length in estuaries increases with flow velocity, tidal excursion length or estuary width, depending on which model. However, these hypotheses were never validated for lack of data and experiments. We present a large dataset and determine the controls on bar shape and dimensions in estuaries, spanning bar lengths from centimeters (experiments) to 10s of kilometers length. First, we visually identified and classified 190 bars, measured their dimensions (width, length, height) and local braiding index. Data on estuarine geometry and tidal characteristics were obtained from governmental databases and literature on case studies. We found that many complex bars can be seen as simple elongated bars partly cut by mutually evasive ebb- and flood-dominated channels. Data analysis shows that bar dimensions scale with estuary dimensions, in particular estuary width. Breaking up the complex bars in simple bars greatly reduced scatter. Analytical bar theory overpredicts bar dimensions by an order of magnitude in case of small estuarine systems. Likewise, braiding index depends on local width-to-depth ratio, as was previously found for river systems. Our results suggest that estuary dimensions determine the order of magnitude of bar dimensions, while tidal characteristics modify this. We will continue to model bars numerically and experimentally. Our dataset on tidal bars enables future studies on the sedimentary architecture of geologically complex tidal deposits and enables studying effects of man-induced perturbations such as dredging and dumping on bar and channel patterns and habitats.

Analyzing the Use of Gaseous Helium as a Pressurant with Cryogenic Propellants with Thermodynamic Venting System Modelling and Test Data

NASA Technical Reports Server (NTRS)

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

2007-01-01

Cryogens are viable candidate propellants for NASA's Lunar and Mars exploration programs. To provide adequate mass flow to the system's engines and/or to prevent feed system cavitation, gaseous helium (GHe) is frequently considered as a pressurant. During low gravity operations, a Thermodynamic Venting System (TVS) is designed to maintain tank pressure during low gravity operations without propellant resettling. Therefore, a series of tests were conducted in the Multi-purpose Hydrogen Test Bed (MHTB) of Marshall Space Flight Center (MSFC) in order to evaluate the effects of GHe pressurant on pressure control performance of a TVS with liquid hydrogen (LH2) and nitrogen (LN2) as the test liquids. The TVS used in these test series consists of a recirculation pump, Joule-Thomson (J-T) expansion valve, and a parallel flow concentric tube heat exchanger combined with a longitudinal spray bar. Using a small amount of liquid extracted from the tank recirculation line, passing it through the J-T valve, and then through the heat exchanger, thermal energy is extracted from the bulk liquid and ullage thereby enabling pressure control. The LH2/GHe tests were performed at fill levels of 90%, 50%, and 25% and LN2/GHe tests were conducted at fill levels of 50% and 25%. Moreover, each test was conducted with a specified tank ullage pressure control band. A one-dimensional TVS performance program was used to analyze and correlate the test data. Predictions and comparisons with test data of ullage pressure and temperature and bulk liquid saturation pressure and temperature with test data are presented.

Identification of the Thickness of Nugget on Worksheet Spot Welding Using Non Destructive Test (NDT) - Effect of Pressure

NASA Astrophysics Data System (ADS)

Sifa, A.; Baskoro, A. S.; Sugeng, S.; Badruzzaman, B.; Endramawan, T.

2018-02-01

Resistance Spot Welding (RSW) is a process of connecting between two worksheet with thermomechanical loading process, RSW is widely used in automotive industry, the quality of splicing spot welding is influenced by several factors. One of the factors at the time of the welding process is pressure. The quality of welding on the nuggets can be determined by undertaking non-destructive testing by using Non Destructive Test (NDT) - Ultrasonic Test. In the NDT test is done by detecting the thickness of the nugget area, the purpose of research conducted to determine the effect of pressure to welding quality with Nugget thickness gauge measurement with Non Destructive Test method and manual measurement with micrometer, Experimental welding process by entering the welding parameters that have been specified and pressure variables 1 -5 bars on the worksheet thickness of 1 mm. The results of testing with NDT show there is addition of thickness in nugget superiority after compare with measurement result of thickness of nugget with micrometer which slightly experience thickness in nugget area, this indicates that the welding results have a connection between worksheet 1 and worksheet 2.

14 CFR 23.843 - Pressurization tests.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Pressurization tests. 23.843 Section 23.843... Pressurization § 23.843 Pressurization tests. (a) Strength test. The complete pressurized cabin, including doors... in § 23.365(d). (b) Functional tests. The following functional tests must be performed: (1) Tests of...

14 CFR 23.843 - Pressurization tests.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Pressurization tests. 23.843 Section 23.843... Pressurization § 23.843 Pressurization tests. (a) Strength test. The complete pressurized cabin, including doors... in § 23.365(d). (b) Functional tests. The following functional tests must be performed: (1) Tests of...

14 CFR 23.843 - Pressurization tests.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Pressurization tests. 23.843 Section 23.843... Pressurization § 23.843 Pressurization tests. (a) Strength test. The complete pressurized cabin, including doors... in § 23.365(d). (b) Functional tests. The following functional tests must be performed: (1) Tests of...

Telescoping magnetic ball bar test gage

DOEpatents

Bryan, James B.

1984-01-01

A telescoping magnetic ball bar test gage for determining the accuracy of machine tools, including robots, and those measuring machines having non-disengageable servo drives which cannot be clutched out. Two gage balls (10, 12) are held and separated from one another by a telescoping fixture which allows them relative radial motional freedom but not relative lateral motional freedom. The telescoping fixture comprises a parallel reed flexure unit (14) and a rigid member (16, 18, 20, 22, 24). One gage ball (10) is secured by a magnetic socket knuckle assembly (34) which fixes its center with respect to the machine being tested. The other gage ball (12) is secured by another magnetic socket knuckle assembly (38) which is engaged or held by the machine in such manner that the center of that ball (12) is directed to execute a prescribed trajectory, all points of which are equidistant from the center of the fixed gage ball (10). As the moving ball (12) executes its trajectory, changes in the radial distance between the centers of the two balls (10, 12) caused by inaccuracies in the machine are determined or measured by a linear variable differential transformer (LVDT) assembly (50, 52, 54, 56, 58, 60) actuated by the parallel reed flexure unit (14). Measurements can be quickly and easily taken for multiple trajectories about several different fixed ball (10) locations, thereby determining the accuracy of the machine.

Analytical potential-density pairs for bars

NASA Astrophysics Data System (ADS)

Vogt, D.; Letelier, P. S.

2010-11-01

An identity that relates multipolar solutions of the Einstein equations to Newtonian potentials of bars with linear densities proportional to Legendre polynomials is used to construct analytical potential-density pairs of infinitesimally thin bars with a given linear density profile. By means of a suitable transformation, softened bars that are free of singularities are also obtained. As an application we study the equilibrium points and stability for the motion of test particles in the gravitational field for three models of rotating bars.

The Measurement of Pressure Through Tubes in Pressure Distribution Tests

NASA Technical Reports Server (NTRS)

Hemke, Paul E

1928-01-01

The tests described in this report were made to determine the error caused by using small tubes to connect orifices on the surface of aircraft to central pressure capsules in making pressure distribution tests. Aluminum tubes of 3/16-inch inside diameter were used to determine this error. Lengths from 20 feet to 226 feet and pressures whose maxima varied from 2 inches to 140 inches of water were used. Single-pressure impulses for which the time of rise of pressure from zero to a maximum varied from 0.25 second to 3 seconds were investigated. The results show that the pressure recorded at the capsule on the far end of the tube lags behind the pressure at the orifice end and experiences also a change in magnitude. For the values used in these tests the time lag and pressure change vary principally with the time of rise of pressure from zero to a maximum and the tube length. Curves are constructed showing the time lag and pressure change. Empirical formulas are also given for computing the time lag. Analysis of pressure distribution tests made on airplanes in flight shows that the recorded pressures are slightly higher than the pressures at the orifice and that the time lag is negligible. The apparent increase in pressure is usually within the experimental error, but in the case of the modern pursuit type of airplane the pressure increase may be 5 per cent. For pressure-distribution tests on airships the analysis shows that the time lag and pressure change may be neglected.

Torsion Tests of 24S-T Aluminum-alloy Noncircular Bar and Tubing

NASA Technical Reports Server (NTRS)

Moore, R L; Paul, D A

1943-01-01

Tests of 24S-T aluminum alloy have been made to determine the yield and ultimate strengths in torsion of noncircular bar and tubing. An approximate basis for predicting these torsional strength characteristics has been indicated. The results show that the torsional stiffness and maximum shearing stresses within the elastic range may be computed quite closely by means of existing formulas based on mathematical analysis and the membrane analogy.

49 CFR 230.35 - Pressure testing.

Code of Federal Regulations, 2010 CFR

2010-10-01

... Pressure Testing of Boilers § 230.35 Pressure testing. The temperature of the steam locomotive boiler shall be raised to at least 70 deg. F any time hydrostatic pressure is applied to the boiler. ... 49 Transportation 4 2010-10-01 2010-10-01 false Pressure testing. 230.35 Section 230.35...

Reaction CH3 + OH studied over the 294-714 K temperature and 1-100 bar pressure ranges.

PubMed

Sangwan, Manuvesh; Chesnokov, Evgeni N; Krasnoperov, Lev N

2012-08-30

Reaction of methyl radicals with hydroxyl radicals, CH(3) + OH → products (1) was studied using pulsed laser photolysis coupled to transient UV-vis absorption spectroscopy over the 294-714 K temperature and 1-100 bar pressure ranges (bath gas He). Methyl radicals were produced by photolysis of acetone at 193.3 nm. Hydroxyl radicals were generated in reaction of electronically excited oxygen atoms O((1)D), produced in the photolysis of N(2)O at 193.3 nm, with H(2)O. Temporal profiles of CH(3) were recorded via absorption at 216.4 nm using xenon arc lamp and a spectrograph; OH radicals were monitored via transient absorption of light from a dc discharge H(2)O/Ar low pressure resonance lamp at ca. 308 nm. The absolute intensity of the photolysis light inside the reactor was determined by an accurate in situ actinometry based on the ozone formation in the presence of molecular oxygen. The results of this study indicate that the rate constant of reaction 1 is pressure independent within the studied pressure and temperature ranges and has slight negative temperature dependence, k(1) = (1.20 ± 0.20) × 10(-10)(T/300)(-0.49) cm(3) molecule(-1) s(-1).

49 CFR 178.814 - Hydrostatic pressure test.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 49 Transportation 2 2010-10-01 2010-10-01 false Hydrostatic pressure test. 178.814 Section 178.814... Testing of IBCs § 178.814 Hydrostatic pressure test. (a) General. The hydrostatic pressure test must be... preparation for the hydrostatic pressure test. For metal IBCs, the test must be carried out before the fitting...

Stress Wave Attenuation in Aluminum Alloy and Mild Steel Specimens Under SHPB Tensile Testing

NASA Astrophysics Data System (ADS)

Pothnis, J. R.; Ravikumar, G.; Arya, H.; Yerramalli, Chandra S.; Naik, N. K.

2018-02-01

Investigations on the effect of intensity of incident pressure wave applied through the striker bar on the specimen force histories and stress wave attenuation during split Hopkinson pressure bar (SHPB) tensile testing are presented. Details of the tensile SHPB along with Lagrangian x- t diagram of the setup are included. Studies were carried out on aluminum alloy 7075 T651 and IS 2062 mild steel. While testing specimens using the tensile SHPB setup, it was observed that the force calculated from the transmitter bar strain gauge was smaller than the force obtained from the incident bar strain gauge. This mismatch between the forces in the incident bar and the transmitter bar is explained on the basis of stress wave attenuation in the specimens. A methodology to obtain force histories using the strain gauges on the specimen during SHPB tensile testing is also presented. Further, scanning electron microscope images and photomicrographs are given. Correlation between the microstructure and mechanical properties is explained. Further, uncertainty analysis was conducted to ascertain the accuracy of the results.

Interfacial toughness of bilayer dental ceramics based on a short-bar, chevron-notch test

PubMed Central

Anunmana, Chuchai; Anusavice, Kenneth J.; Mecholsky, John J.

2009-01-01

Objective The objective of this study was to test the null hypothesis that the interfacial toughness of each of two types of bonded core-veneer bilayer ceramics is not significantly different from the apparent fracture toughness of the control monolithic glass veneer. Methods T-shaped short bars of a lithia-disilicate glass-ceramic core (LC) and yttria-stabilized polycrystalline zirconia core ceramic (ZC) were prepared according to the manufacturer's recommendations. V-shaped notches were prepared by using 25-μm-thick palladium foil, leaving the chevron notch area exposed, and the bars were veneered with a thermally compatible glass veneer (LC/GV and ZC/GV). Additionally, we also bonded the glass veneer to itself as a control group (GV/GV). Specimens were kept in distilled water for 30 days before testing in tension. Eight glass veneer bars were prepared for the analysis of fracture toughness test using the indentation-strength technique. Results The mean interfacial toughness of the LC/GV group was 0.69 [0.11] MPa·m1/2, and did not significantly differ from that of the GV/GV control group, 0.74 (0.17) MPa·m1/2 (p > 0.05). However, the difference between the mean interfacial toughness of the ZC/GV group, 0.13 (0.07) MPa·m1/2, and the LC/GV and the GV/GV groups was statistically significant (p<0.05). Significance For bilayer all-ceramic restorations with high-strength core materials, the veneering ceramics are the weakest link in the design of the structure. Since all-ceramic restorations often fail from chipping of veneer layers or crack initiation at the interface, the protective effects of thermal mismatch stresses oral prosthesis design should be investigated. PMID:19818486

Corrosion Assessment of Steel Bars Used in Reinforced Concrete Structures by Means of Eddy Current Testing

PubMed Central

de Alcantara, Naasson P.; da Silva, Felipe M.; Guimarães, Mateus T.; Pereira, Matheus D.

2015-01-01

This paper presents a theoretical and experimental study on the use of Eddy Current Testing (ECT) to evaluate corrosion processes in steel bars used in reinforced concrete structures. The paper presents the mathematical basis of the ECT sensor built by the authors; followed by a finite element analysis. The results obtained in the simulations are compared with those obtained in experimental tests performed by the authors. Effective resistances and inductances; voltage drops and phase angles of wound coil are calculated using both; simulated and experimental data; and demonstrate a strong correlation. The production of samples of corroded steel bars; by using an impressed current technique is also presented. The authors performed experimental tests in the laboratory using handmade sensors; and the corroded samples. In the tests four gauges; with five levels of loss-of-mass references for each one were used. The results are analyzed in the light of the loss-of-mass and show a strong linear behavior for the analyzed parameters. The conclusions emphasize the feasibility of the proposed technique and highlight opportunities for future works. PMID:26712754

Corrosion Assessment of Steel Bars Used in Reinforced Concrete Structures by Means of Eddy Current Testing.

PubMed

de Alcantara, Naasson P; da Silva, Felipe M; Guimarães, Mateus T; Pereira, Matheus D

2015-12-24

This paper presents a theoretical and experimental study on the use of Eddy Current Testing (ECT) to evaluate corrosion processes in steel bars used in reinforced concrete structures. The paper presents the mathematical basis of the ECT sensor built by the authors; followed by a finite element analysis. The results obtained in the simulations are compared with those obtained in experimental tests performed by the authors. Effective resistances and inductances; voltage drops and phase angles of wound coil are calculated using both; simulated and experimental data; and demonstrate a strong correlation. The production of samples of corroded steel bars; by using an impressed current technique is also presented. The authors performed experimental tests in the laboratory using handmade sensors; and the corroded samples. In the tests four gauges; with five levels of loss-of-mass references for each one were used. The results are analyzed in the light of the loss-of-mass and show a strong linear behavior for the analyzed parameters. The conclusions emphasize the feasibility of the proposed technique and highlight opportunities for future works.

Proof testing a bridge deck design with glass fiber reinforced polymer bars as top mat of reinforcement.

DOT National Transportation Integrated Search

2003-01-01

The primary objective of this project was to test a full-scale prototype of a bridge deck design containing glass fiber reinforced polymer (GFRP) bars as the top mat of reinforcement. The test deck mimics the design of the deck of one span of the new...

Reaction OH + OH studied over the 298-834 K temperature and 1-100 bar pressure ranges.

PubMed

Sangwan, Manuvesh; Chesnokov, Evgeni N; Krasnoperov, Lev N

2012-06-21

Self-reaction of hydroxyl radicals, OH + OH → H(2)O + O (1a) and OH + OH → H(2)O(2) (1b), was studied using pulsed laser photolysis coupled to transient UV-vis absorption spectroscopy over the 298-834 K temperature and 1-100 bar pressure ranges (bath gas He). A heatable high-pressure flow reactor was employed. Hydroxyl radicals were prepared using reaction of electronically excited oxygen atoms, O((1)D), produced in photolysis of N(2)O at 193 nm, with H(2)O. The temporal behavior of OH radicals was monitored via transient absorption of light from a dc discharge in H(2)O/Ar low-pressure resonance lamp at ca. 308 nm. The absolute intensity of the photolysis light was determined by accurate in situ actinometry based on the ozone formation in the presence of molecular oxygen. The results of this study combined with the literature data indicate that the rate constant of reaction 1a, associated with the pressure independent component, decreases with temperature within the temperature range 298-414 K and increases above 555 K. The pressure dependent rate constant for (1b) was parametrized using the Troe expression as k(1b,inf) = (2.4 ± 0.6) × 10(-11)(T/300)(-0.5) cm(3) molecule(-1) s(-1), k(1b,0) = [He] (9.0 ± 2.2) × 10(-31)(T/300)(-3.5±0.5) cm(3) molecule(-1) s(-1), F(c) = 0.37.

Growth of the microalgae Neochloris oleoabundans at high partial oxygen pressures and sub-saturating light intensity.

PubMed

Sousa, Cláudia; de Winter, Lenneke; Janssen, Marcel; Vermuë, Marian H; Wijffels, René H

2012-01-01

The effect of partial oxygen pressure on growth of Neochloris oleoabundans was studied at sub-saturating light intensity in a fully-controlled stirred tank photobioreactor. At the three partial oxygen pressures tested (P(O)₂= 0.24; 0.63; 0.84 bar), the specific growth rate was 1.38; 1.36 and 1.06 day(-1), respectively. An increase of the P(CO)₂from 0.007 to 0.02 bar at P(O₂) of 0.84 bar resulted in an increase in the growth rate from 1.06 to 1.36 day(-1). These results confirm that the reduction of algal growth at high oxygen concentrations at sub-saturating light conditions is mainly caused by competitive inhibition of Rubisco. This negative effect on growth can be overcome by restoring the O(2)/CO(2) ratio by an increase in the partial carbon dioxide pressure. In comparison to general practice (P(O(2)) = 0.42 bar), working at partial O(2) pressure of 0.84 bar could reduce the energy requirement for degassing by a factor of 3-4. Copyright © 2011 Elsevier Ltd. All rights reserved.

33 CFR 159.109 - Pressure test.

Code of Federal Regulations, 2010 CFR

2010-07-01

... the tank, whichever is greater. The tank must hold the water at this pressure for 1 hour with no... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Pressure test. 159.109 Section...) POLLUTION MARINE SANITATION DEVICES Design, Construction, and Testing § 159.109 Pressure test. Any sewage...

Preparation of a Breadfruit Flour Bar.

PubMed

Nochera, Carmen L; Ragone, Diane

2016-05-20

Breadfruit is a nutritious, high energy food with a low quantity of protein but excellent protein quality. It has the potential to be developed into desired products which will help increase its utilization and add value to the crop. The overall purposes of this investigation were to develop a portable, nutritious, ready-to-eat breadfruit product (bar), test the sensory qualities of the product, and evaluate the nutritional properties of the product. Flour made from the Micronesian variety, Meinpadahk ( Artocarpus altilis × Artocarpus mariannensis ), was utilized for the development of the breadfruit bar. Breadfruit is a rich source of fiber, vitamins such as vitamin C, minerals such as potassium, and phytochemicals such as flavonoids. Nutritional labeling indicates that the breadfruit bar is high in carbohydrates and low in fat, and sensory evaluation indicates that 81% of the panelists found the bar acceptable while 19% disliked the bar. The breadfruit bar can provide an appealing and inexpensive gluten-free food source based on locally available breadfruit.

Pneumatic pressure wave generator provides economical, simple testing of pressure transducers

NASA Technical Reports Server (NTRS)

Gaal, A. E.; Weldon, T. P.

1967-01-01

Testing device utilizes the change in pressure about a bias or reference pressure level produced by displacement of a center-driven piston in a closed cylinder. Closely controlled pneumatic pressure waves allow testing under dynamic conditions.

Short-core acoustic resonant bar test and x-ray CT imaging on sandstone samples during super-critical CO2 flooding and dissolution

NASA Astrophysics Data System (ADS)

Nakagawa, S.; Kneafsey, T. J.; Daley, T. M.; Freifeld, B. M.

2010-12-01

Geological sequestration of CO2 requires accurate monitoring of the spatial distribution and pore-level saturation of super-critical (sc-) CO2 for both optimizing reservoir performance and satisfying regulatory requirements. Fortunately, thanks to the high compliance of sc-CO2 compared to brine under in-situ temperatures and pressures, injection of sc-CO2 into initially brine-saturated rock will lead to significant reductions in seismic velocity and increased attenuation of seismic waves. Because of the frequency-dependent nature of this relationship, its determination requires testing at low frequencies (10 Hz-10 kHz) that are not usually employed in the laboratory. In this paper, we present the changes in seismic wave velocities and attenuation in sandstone cores during sc-CO2 core flooding and during subsequent brine re-injection and CO2 removal via convection and dissolution. The experiments were conducted at frequencies near 1 kHz using a variation of the acoustic resonant bar technique, called the Split Hopkinson Resonant Bar (SHRB) method, which allows measurements under elevated temperatures and pressures (up to 120°C, 35 MPa), using a short (several cm long) core. Concurrent x-ray CT scanning reveals sc-CO2 saturation and distribution within the cores. The injection experiments revealed different CO2 patch size distributions within the cores between the injection phase and the convection/dissolution phase of the tests. The difference was reflected particularly in the P-wave velocities and attenuation. Also, compared to seismic responses, which were separately measured during a gas CO2 injection/drainage test, the seismic responses from the sc-CO2 test showed measurable changes over a wider range of brine saturation. Considering the proximity of the frequency band employed by our measurement to the field seismic measurements, this result implies that seismic monitoring of sc-CO2, if constrained by laboratory data and interpreted using a proper

Mechanisms linking sediment supply and bar morphology: Results from a straight flume with alternate bars

NASA Astrophysics Data System (ADS)

Braudrick, C. A.; Minear, J. T.; Dietrich, W. E.; Dehart, M.; Sklar, L. S.

2008-12-01

One of the largest uncertainties in routing sediment through drainage networks is predicting the degree to which changes in sediment supply are mitigated by changes in sediment storage in bars. We hypothesize that changes in topographic steering link sediment supply and bar morphology. This hypothesis posits that increased sediment supply would enhance topographic steering over the bar, causing the bar to advance laterally into the pool. Contrarily, decreased supply would diminish topographic steering, causing bars to shrink laterally and pools to expand. We examined this hypothesis in a 28-m long, 0.86-m wide flume with a constant discharge of 5.4 l/s and sand with a median grain size of 0.8 mm. The conditions were sufficient to support alternate bars downstream of the upper 8-10 m, and the flume was run for approximately 65 hours at a constant discharge and sediment feed. The equilibrium slope was 0.0033. Once the channel reached equilibrium, the sediment feed was turned off while the discharge was held constant. During the first 25 hours after the feed was stopped, the sediment transport rate at the downstream end of the flume increased from 9.8 to 10.5 kg/hr as sediment was provided by incision at the upstream end of the flume. Because the bed was the only sediment source, sediment supply increased with distance down the flume. Once the feed was shut off, bar response differed between the upstream and downstream portions of the flume. Bars at the downstream end of the flume, where sediment supply increased relative to equilibrium conditions, swelled into the pool. These changes in bar morphology were accompanied by a decrease in surface grain size. Further upstream, where sediment supply was lower, the bars shrunk. These results suggest that there may be a linkage between topographic steering, bar morphology, and sediment supply, but further numerical tests and experimental manipulations are necessary to verify this linkage and to account for the effect of the

Predictions for the $$\\bar{B}^{0}\\rightarrow \\bar{K}^{\\ast 0}$$ X(YZ) and $$\\bar{B}^{0}_{s}\\rightarrow\\phi$$ X(YZ) with X(4160), Y(3940), Z(3930)

DOE PAGES

Liang, Wei -Hong; Molina, R.; Xie, Ju -Jun; ...

2015-05-22

We investigate the decay ofmore » $$\\bar B^0 \\to \\bar K^{*0} R$$ and $$\\bar B^0_s \\to \\phi R$$ with $R$ being the $X(4160)$, $Y(3940)$, $Z(3930)$ resonances. Under the assumption that these states are dynamically generated from the vector-vector interaction, as has been concluded from several theoretical studies, we use a reaction mechanism of quark production at the elementary level, followed by hadronization of one final $$q \\bar q$$ pair into two vectors and posterior final state interaction of this pair of vector mesons to produce the resonances. With this procedure we are able to predict five ratios for these decays, which are closely linked to the dynamical nature of these states, and also predict the order of magnitude of the branching ratios which we find of the order of $$10^{-4}$$, well within the present measurable range. In order to further test the dynamical nature of these resonances we study the $$\\bar B^0_s \\to \\phi D^* \\bar D^*$$ and $$\\bar B^0_s \\to \\phi D_s^* \\bar D_s^*$$ decays close to the $$D^* \\bar D^*$$ and $$D_s^* \\bar D_s^*$$ thresholds and make predictions for the ratio of the mass distributions in these decays and the $$\\bar B^0_s \\to \\phi R$$ decay widths. In conclusion, the measurement of these decays rates can help unravel the nature of these resonances.« less

49 CFR 178.605 - Hydrostatic pressure test.

Code of Federal Regulations, 2012 CFR

2012-10-01

... hydraulic pressure (gauge) applied, taken at the top of the receptacle, and determined by any one of the... 49 Transportation 3 2012-10-01 2012-10-01 false Hydrostatic pressure test. 178.605 Section 178.605... Packagings and Packages § 178.605 Hydrostatic pressure test. (a) General. The hydrostatic pressure test must...

49 CFR 178.605 - Hydrostatic pressure test.

Code of Federal Regulations, 2014 CFR

2014-10-01

... hydraulic pressure (gauge) applied, taken at the top of the receptacle, and determined by any one of the... 49 Transportation 3 2014-10-01 2014-10-01 false Hydrostatic pressure test. 178.605 Section 178.605... Packagings and Packages § 178.605 Hydrostatic pressure test. (a) General. The hydrostatic pressure test must...

Study of aging and embrittlement of microalloyed steel bars

NASA Astrophysics Data System (ADS)

Campillo, B.; Perez, R.; Martinez, L.

1996-10-01

The aging of hooks, anchors, and other bent reinforcing steel bars in concrete structures are considered in modern international standards. Rebend test procedures have been designed in order to predict the aging embrittlement susceptibility by submerging bent reinforcing bar specimens in boiling water. Subsequently the bars are rebent or straightened in order to determine the loss of ductility or embrittlement of the aged material. The present work considers the influence of carbon, sulfur, and niobium on the performance of reinforcing bars in rebend tests of 300 heats of microalloyed steel bars with a variety of compositions. The microstructural evidence and the statistical results clearly indicate the strong influence of carbon and sulfur on rebend failure, while niobium-rich precipitates contribute to the hardening of the ferrite grains during aging.

High pressure oxygen furnace

DOEpatents

Morris, D.E.

1992-07-14

A high temperature high pressure oxygen furnace having a hybrid partially externally heated construction is disclosed. A metallic bar fabricated from an alloy having a composition of at least 45% nickel, 15% chrome, and 10% tungsten is utilized, the preferred alloy including 55% nickel, 22% chrome, 14% tungsten, 2% molybdenum, 3% iron (maximum) and 5% cobalt (maximum). The disclosed alloy is fabricated into 11/4 inch bar stock and has a length of about 17 inches. This bar stock is gun drilled for over 16 inches of its length with 0.400 inch aperture to define a closed high temperature, high pressure oxygen chamber. The opposite and closed end of the bar is provided with a small support aperture into which both a support and a thermocouple can be inserted. The closed end of the gun drilled bar is inserted into an oven, preferably heated by standard nickel chrome electrical elements and having a heavily insulated exterior. 5 figs.

High pressure oxygen furnace

DOEpatents

Morris, Donald E.

1992-01-01

A high temperature high pressure oxygen furnace having a hybrid partially externally heated construction is disclosed. A metallic bar fabricated from an alloy having a composition of at least 45% nickel, 15% chrome, and 10% tungsten is utilized (the preferred alloy including 55% nickel, 22% chrome, 14% tungsten, 2% molybdenum, 3% iron (maximum) and 5% cobalt (maximum). The disclosed alloy is fabricated into 11/4 inch bar stock and has a length of about 17 inches. This bar stock is gun drilled for over 16 inches of its length with 0.400 inch aperture to define a closed high temperature, high pressure oxygen chamber. The opposite and closed end of the bar is provided with a small support aperture into which both a support and a thermocouple can be inserted. The closed end of the gun drilled bar is inserted into an oven, preferably heated by standard nickel chrome electrical elements and having a heavily insulated exterior.

49 CFR 178.814 - Hydrostatic pressure test.

Code of Federal Regulations, 2012 CFR

2012-10-01

..., 21B, and 21N, for Packing Group I solids: 250 kPa (36 psig) gauge pressure. (4) For rigid plastic IBC... 49 Transportation 3 2012-10-01 2012-10-01 false Hydrostatic pressure test. 178.814 Section 178.814... Hydrostatic pressure test. (a) General. The hydrostatic pressure test must be conducted for the qualification...

49 CFR 178.814 - Hydrostatic pressure test.

Code of Federal Regulations, 2011 CFR

2011-10-01

..., 21B, and 21N, for Packing Group I solids: 250 kPa (36 psig) gauge pressure. (4) For rigid plastic IBC... 49 Transportation 3 2011-10-01 2011-10-01 false Hydrostatic pressure test. 178.814 Section 178.814... Hydrostatic pressure test. (a) General. The hydrostatic pressure test must be conducted for the qualification...

49 CFR 178.814 - Hydrostatic pressure test.

Code of Federal Regulations, 2014 CFR

2014-10-01

..., 21B, and 21N, for Packing Group I solids: 250 kPa (36 psig) gauge pressure. (4) For rigid plastic IBC... 49 Transportation 3 2014-10-01 2014-10-01 false Hydrostatic pressure test. 178.814 Section 178.814... Hydrostatic pressure test. (a) General. The hydrostatic pressure test must be conducted for the qualification...

49 CFR 178.814 - Hydrostatic pressure test.

Code of Federal Regulations, 2013 CFR

2013-10-01

..., 21B, and 21N, for Packing Group I solids: 250 kPa (36 psig) gauge pressure. (4) For rigid plastic IBC... 49 Transportation 3 2013-10-01 2013-10-01 false Hydrostatic pressure test. 178.814 Section 178.814... Hydrostatic pressure test. (a) General. The hydrostatic pressure test must be conducted for the qualification...

49 CFR 178.605 - Hydrostatic pressure test.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 49 Transportation 2 2010-10-01 2010-10-01 false Hydrostatic pressure test. 178.605 Section 178.605... Testing of Non-bulk Packagings and Packages § 178.605 Hydrostatic pressure test. (a) General. The hydrostatic pressure test must be conducted for the qualification of all metal, plastic, and composite...

Arch bar stabilization of endotracheal tubes in children with facial burns.

PubMed

Perrotta, V J; Stern, J D; Lo, A K; Mitra, A

1995-01-01

Endotracheal tube stabilization in children with facial burns can be difficult. Several methods rely on straps or complex devices that apply undesirable pressure to the face, potentially destroying skin grafts and making wound care difficult. Techniques that rely on a single wire or suture can be unreliable. Presented here is the arch bar method of endotracheal tube stabilization, which appears to be free of these problems. This method employs a standard dental arch bar secured to four maxillary teeth with 24-gauge stainless steel wire. The endotracheal tube is anchored to the arch bar with two pieces of wire or suture material. The arch bar method of endotracheal tube stabilization was used on three patients in the burn center at St. Christopher's Hospital for Children. Wound care and successful skin grafting were performed without difficulty. No complications related to the arch bars occurred.

Finite Element Simulations to Explore Assumptions in Kolsky Bar Experiments.

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

Crum, Justin

2015-08-05

The chief purpose of this project has been to develop a set of finite element models that attempt to explore some of the assumptions in the experimental set-up and data reduction of the Kolsky bar experiment. In brief, the Kolsky bar, sometimes referred to as the split Hopkinson pressure bar, is an experimental apparatus used to study the mechanical properties of materials at high strain rates. Kolsky bars can be constructed to conduct experiments in tension or compression, both of which are studied in this paper. The basic operation of the tension Kolsky bar is as follows: compressed air ismore » inserted into the barrel that contains the striker; the striker accelerates towards the left and strikes the left end of the barrel producing a tensile stress wave that propogates first through the barrel and then down the incident bar, into the specimen, and finally the transmission bar. In the compression case, the striker instead travels to the right and impacts the incident bar directly. As the stress wave travels through an interface (e.g., the incident bar to specimen connection), a portion of the pulse is transmitted and the rest reflected. The incident pulse, as well as the transmitted and reflected pulses are picked up by two strain gauges installed on the incident and transmitted bars as shown. By interpreting the data acquired by these strain gauges, the stress/strain behavior of the specimen can be determined.« less

49 CFR 178.605 - Hydrostatic pressure test.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 49 Transportation 3 2013-10-01 2013-10-01 false Hydrostatic pressure test. 178.605 Section 178.605... Packagings and Packages § 178.605 Hydrostatic pressure test. (a) General. The hydrostatic pressure test must... intended to contain liquids and be performed periodically as specified in § 178.601(e). This test is not...

49 CFR 178.605 - Hydrostatic pressure test.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 49 Transportation 3 2011-10-01 2011-10-01 false Hydrostatic pressure test. 178.605 Section 178.605... Packagings and Packages § 178.605 Hydrostatic pressure test. (a) General. The hydrostatic pressure test must... intended to contain liquids and be performed periodically as specified in § 178.601(e). This test is not...

Special Workshop: Kolsky/Split Hopkinson Pressure Bar Testing of Ceramics

DTIC Science & Technology

2006-09-01

merit) control armor performance and how these properties are controlled/ influenced by intrinsic (crystal structure, phase transitions, and single...reproducibility uncertainties (estimates of precision) could be quantified and also identify key parameters that should be controlled in SHPB/Kolsky testing...control performance? Are there figures of merit? How are the mechanical properties influenced by intrinsic and extrinsic material characteristics

Development of ceramic-coated weld backing bars

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

Eggleston, B.R.

1994-10-20

In shipbuilding and many other industries, copper weld backing bars are used to draw the heat out of the weld. The problem that some users of these bars encounter is that these bars, on occasion, actually melt in spots and become welded to the weld plates. After this happens a number of times, the backing bar becomes so degraded that it must be either discarded or machined, both of which are very costly and time-consuming actions. To avoid this fusion between the backing bar and the weld plate, the weld processes that are used cannot be ones of high beatmore » input. This requirement is very limiting when thick plates are being welded. The plates must be beveled, and more weld passes must be run. These problems are also costly and time consuming. The aim of this project is to find a way to produce backing bars with nearly the same `chilling` effect but with both a greater resistance to molten metal and resistance to arcing to the backing bar itself. A possible solution currently being tested is to coat the copper bars with a thin layer of a ceramic coating. The procedure used was to coat the copper bars with either alumina or spinel by a plasma spraying method.« less

Performance simulation of BaBar DIRC bar boxes in TORCH

NASA Astrophysics Data System (ADS)

Föhl, K.; Brook, N.; Castillo García, L.; Cussans, D.; Forty, R.; Frei, C.; Gao, R.; Gys, T.; Harnew, N.; Piedigrossi, D.; Rademacker, J.; Ros García, A.; van Dijk, M.

2017-12-01

TORCH is a large-area precision time-of-flight detector based on the DIRC principle. The DIRC bar boxes of the BaBar experiment at SLAC could possibly be reused to form a part of the TORCH detector time-of-flight wall area, proposed to provide positive particle identification of low momentum kaons in the LHCb experiment at CERN. For a potential integration of BaBar bar boxes into TORCH, new imaging readout optics are required. From the several designs of readout optics that have been considered, two are used in this paper to study the effect of BaBar bar optical imperfections on the detector reconstruction performance. The kaon-pion separation powers obtained from analysing simulated photon hit patterns show the performance reduction for a BaBar bar of non-square geometry compared to a perfectly rectangular cross section.

PREDICTIONS FOR $B \\to \\tau \\bar{\\mu} + \\mu \\bar{\\tau}$

NASA Astrophysics Data System (ADS)

Boubaa, Dris; Datta, Alakabha; Duraisamy, Murugeswaran; Khalil, Shaaban

2013-12-01

The observation of B -> τ \\bar {μ } + μ \\bar {τ } at present experiments would be a clear sign of new physics. In this paper, we calculate this process in an extended Higgs sector framework where the decay is mediated by the exchange of spin zero particle with flavor changing neutral current couplings. If we identify the scalar with the newly discovered state at LHC with a mass 125 GeV then we find that, after imposing all experimental constraints, the BR(Bs -> τ \\bar {μ } + μ \\bar {τ }) can be as high as 10-6 and BR (Bd -> τ \\bar {μ } + μ \\bar {τ }) can be as high as 10-7. We also calculate this process in the minimal supersymmetric standard model and find the BR(Bs ->τ \\bar {μ } + μ \\bar {τ }) is typically of the order 10-8.

33 CFR 183.586 - Pressure impulse test.

Code of Federal Regulations, 2010 CFR

2010-07-01

...) BOATING SAFETY BOATS AND ASSOCIATED EQUIPMENT Fuel Systems Tests § 183.586 Pressure impulse test. A fuel... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Pressure impulse test. 183.586... pressure test under § 183.580. (b) If the tank is non-metallic, fill it to capacity with a gasoline that...

33 CFR 183.586 - Pressure impulse test.

Code of Federal Regulations, 2014 CFR

2014-07-01

...) BOATING SAFETY BOATS AND ASSOCIATED EQUIPMENT Fuel Systems Tests § 183.586 Pressure impulse test. A fuel... 33 Navigation and Navigable Waters 2 2014-07-01 2014-07-01 false Pressure impulse test. 183.586... pressure test under § 183.580. (b) If the tank is non-metallic, fill it to capacity with a gasoline that...

33 CFR 183.586 - Pressure impulse test.

Code of Federal Regulations, 2013 CFR

2013-07-01

...) BOATING SAFETY BOATS AND ASSOCIATED EQUIPMENT Fuel Systems Tests § 183.586 Pressure impulse test. A fuel... 33 Navigation and Navigable Waters 2 2013-07-01 2013-07-01 false Pressure impulse test. 183.586... pressure test under § 183.580. (b) If the tank is non-metallic, fill it to capacity with a gasoline that...

33 CFR 183.586 - Pressure impulse test.

Code of Federal Regulations, 2012 CFR

2012-07-01

...) BOATING SAFETY BOATS AND ASSOCIATED EQUIPMENT Fuel Systems Tests § 183.586 Pressure impulse test. A fuel... 33 Navigation and Navigable Waters 2 2012-07-01 2012-07-01 false Pressure impulse test. 183.586... pressure test under § 183.580. (b) If the tank is non-metallic, fill it to capacity with a gasoline that...

33 CFR 183.586 - Pressure impulse test.

Code of Federal Regulations, 2011 CFR

2011-07-01

...) BOATING SAFETY BOATS AND ASSOCIATED EQUIPMENT Fuel Systems Tests § 183.586 Pressure impulse test. A fuel... 33 Navigation and Navigable Waters 2 2011-07-01 2011-07-01 false Pressure impulse test. 183.586... pressure test under § 183.580. (b) If the tank is non-metallic, fill it to capacity with a gasoline that...

33 CFR 159.109 - Pressure test.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 33 Navigation and Navigable Waters 2 2011-07-01 2011-07-01 false Pressure test. 159.109 Section 159.109 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) POLLUTION MARINE SANITATION DEVICES Design, Construction, and Testing § 159.109 Pressure test. Any sewage...

Gaseous Vortices in Barred Spiral Galaxies

NASA Technical Reports Server (NTRS)

England, Martin N.; Hunter, James H., Jr.

1995-01-01

During the course of examining many two-dimensional, as well as a smaller sample of three-dimensional, models of gas flows in barred spiral galaxies, we have been impressed by the ubiquitous presence fo vortex pairs, oriented roughly perpendicular to their bars, with one vortex on each side. The vortices are obvious only when viewed in the bar frame, and the centers of their velocity fields usually are near Lagrangian points L(sub 4,5). In all models that we have studied, the vortices form on essentially the same time scale as that for the development of gaseous spiral arms, typically two bar rotations. Usually the corotation radius, r(sub c), lies slightly beyond the end of the bar. Depending upon the mass distributions of the various components, gas spirals either into, or out of, the vortices: In the former case, the vortices become regions of high density, whereas the opposite is true if the gas spirals out of a vortex. The models described in this paper have low-density vortices, as do most of the models we have studied. Moreover, usually the vortex centers lie approximately within +/- 15 deg of L(sub 4,5). In the stellar dynamic limit, when pressure and viscous forces are absent, short-period orbits exist, centered on L(sub 4,5). These orbits need not cross and therefore their morphology is that of gas streamlines, that is, vortices. We believe that the gas vortices in our models are hydrodynamic analogues of closed, short-period, libration orbits centered on L(sub 4,5).

Design and development of a novel strain gauge automatic pasting device for mini split Hopkinson pressure bar

NASA Astrophysics Data System (ADS)

Huang, Wenkai; Huan, Shi; He, Junfeng; Jiang, Jichang

2018-03-01

In a split Hopkinson pressure bar (SHPB) experiment, the pasting quality of strain gauges will directly affect the accuracy of the measurement results. The traditional method of pasting the strain gauges is done manually by the experimenter. In the process of pasting, it is easy to shift or twist the strain gauge, and the experimental results are greatly affected by human factors. In this paper, a novel type automatic pasting device for strain gauges is designed and developed, which can be used to accurately and rapidly paste the strain gauges. The paste quality is reliable, and it can guarantee the consistency of SHPB experimental measurement. We found that a clamping force of 74 N achieved a success rate of 97%, whilst ensuring good adhesion.

Nearshore bars and the break-point hypothesis

USGS Publications Warehouse

Sallenger, A.H.; Howd, P.A.

1989-01-01

The set of hypotheses calling for bar formation at the break point was tested with field data. During two different experiments, waves were measured across the surf zone coincident with the development of a nearshore bar. We use a criterion, based on the wave height to depth ratio, to determine the offshore limit of the inner surf zone. During the first experiment, the bar became better developed and migrated offshore while remaining well within the inner surf zone. During the second experiment, the surf zone was narrower and we cannot rule out the possibility of break point processes contributing to bar development. We conclude that bars are not necessarily coupled with the break point and can become better developed and migrate offshore while being in the inner surf zone landward from initial wave breaking in the outer surf zone. ?? 1989.

Passivity of the bars manufactured using current technologies: laser-sintering, casting, and milling

NASA Astrophysics Data System (ADS)

Popescu, Diana; Popescu, Sabin; Pop, Daniel; Jivanescu, Anca; Todea, Carmen

2014-01-01

Implant overdentures are often selected as therapeutic options for the treatment of edentulous mandibles. "Passive-fit" between the mesostructures and the implants plays an important role in the longevity of the implant-prosthetic assembly in the oral cavity. "Mis-fit" can cause mechanical or biological complications. The purpose of this test was to investigate the passive adaptation of the bars manufactured through different technologies, and in this respect two bars (short and long) were fabricated by each process: laser-sintering, milling, casting. The tensions induced by tightening the connection screw between the bars and the underlying implants were recorded using strain gauges and used as measuring and comparing tool in testing the bars' "passivity". The results of the test showed that the milled bars had the best "passive-fit", followed by laser-sintered bars, while cast bars had the lowest adaptation level.

49 CFR 178.255-12 - Pressure test.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 49 Transportation 3 2013-10-01 2013-10-01 false Pressure test. 178.255-12 Section 178.255-12... Portable Tanks § 178.255-12 Pressure test. (a) Each completed portable tank prior to application of lining... the test, and applying a pressure of 60 psig. The tank shall be capable of holding the prescribed...

Gaseous Structures in Barred Galaxies: Effects of the Bar Strength

NASA Astrophysics Data System (ADS)

Kim, Woong-Tae; Seo, Woo-Young; Kim, Yonghwi

2012-10-01

Using hydrodynamic simulations, we investigate the physical properties of gaseous substructures in barred galaxies and their relationships with the bar strength. The gaseous medium is assumed to be isothermal and unmagnetized. The bar potential is modeled as a Ferrers prolate with index n. To explore situations with differing bar strength, we vary the bar mass f bar relative to the spheroidal component as well as its aspect ratio { R}. We derive expressions as functions of f bar and { R} for the bar strength Qb and the radius r(Qb ) where the maximum bar torque occurs. When applied to observations, these expressions suggest that bars in real galaxies are most likely to have f bar ~ 0.25-0.50 and n <~ 1. Dust lanes approximately follow one of the x 1-orbits and tend to be straighter under a stronger and more elongated bar, but are insensitive to the presence of self-gravity. A nuclear ring of a conventional x 2 type forms only when the bar is not so massive or elongated. The radius of an x 2-type ring is generally smaller than the inner Lindblad resonance, decreases systematically with increasing Qb , and is slightly larger when self-gravity is included. This is evidence that the ring position is not determined by the resonance, but instead by the amount of angular momentum loss at dust-lane shocks. Nuclear spirals exist only when the ring is of the x 2 type and is sufficiently large in size. Unlike the other features, nuclear spirals are transient in that they start out being tightly wound and weak, and then, due to the nonlinear effect, unwind and become stronger until they turn into shocks, with an unwinding rate that is higher for larger Qb . The mass inflow rate to the galaxy center is found to be less than 0.01 M ⊙ yr-1 for models with Qb <~ 0.2, while becoming larger than 0.1 M ⊙ yr-1 when Qb >~ 0.2 and self-gravity is included.

Quasi-CW Laser Diode Bar Life Tests

NASA Technical Reports Server (NTRS)

Stephen, Mark A.; Krainak, Michael A.; Dallas, Joseph L.

1997-01-01

NASA's Goddard Space Flight Center is developing technology for satellite-based, high peak power, LIDAR transmitters requiring 3-5 years of reliable operation. Semi-conductor laser diodes provide high efficiency pumping of solid state lasers with the promise of long-lived, reliable operation. 100-watt quasi- CW laser diode bars have been baselined for the next generation laser altimeters. Multi-billion shot lifetimes are required. The authors have monitored the performance of several diodes for billions of shots and investigated operational modes for improving diode lifetime.

Laboratory Study on Macro-Features of Wave Breaking Over Bars and Artificial Reefs

DTIC Science & Technology

1990-07-01

Prototype and Model Conditions of Case CE400 ( Pilot Test ) . 72 7 List of Design Parameters for Base Tests ... ........... . 72 8 List of Design Parameters...bar configurations, and the procedure was repeated. Pilot test 112. A pilot test was performed as a trial of the methodology and vali- dation of the...criterion on bar depth given by Larson and Kraus (1989) prior to actual testing . In this pilot test , the wave conditions and equilibrium bar formed in a

Effects of the Bar Strength of Gaseous Features in Barred Galaxies

NASA Astrophysics Data System (ADS)

Kim, Woong-Tae; Seo, W.; Kim, Y.

2013-01-01

Barred galaxies commonly possess gaseous structures such as a pair of dust lanes, a nuclear ring, and nuclear spirals at their centers. We use hydrodynamic simulations to study the physical properties of the gaseous structures in barred galaxies and their relationships with the bar strength. We vary the bar mass fbar relative to the spheroidal component as well as its aspect ratio. We derive expressions for the bar strength Qb and the radius where the maximum bar torque occurs. When applied to observations, these expressions suggest that bars in real galaxies are most likely to have fbar = 0.25-0.5. Dust lanes approximately follow one of x1-orbits and tend to be more straight under a stronger and more elongated bar. A nuclear ring of a conventional x2 type forms only when the bar is not so massive or elongated. The radius of an x2-type ring is generally smaller than the inner Lindblad resonance, decreases systematically with increasing Qb, evidencing that the ring position is not determined by the resonance but by the bar strength. Nuclear spirals exist only when the ring is of the x2-type and sufficiently large in size. Unlike the other features, nuclear spirals are transient in that they start out as being tightly-wound and weak, and then due to the nonlinear effect unwind and become stronger until turning into shocks, with an unwinding rate higher for larger Qb. These results suggest that the bar strength is the primary factor that determine the properties of gaseous structures in barred galaxies.

Novel designs for application specific MEMS pressure sensors.

PubMed

Fragiacomo, Giulio; Reck, Kasper; Lorenzen, Lasse; Thomsen, Erik V

2010-01-01

In the framework of developing innovative microfabricated pressure sensors, we present here three designs based on different readout principles, each one tailored for a specific application. A touch mode capacitive pressure sensor with high sensitivity (14 pF/bar), low temperature dependence and high capacitive output signal (more than 100 pF) is depicted. An optical pressure sensor intrinsically immune to electromagnetic interference, with large pressure range (0-350 bar) and a sensitivity of 1 pm/bar is presented. Finally, a resonating wireless pressure sensor power source free with a sensitivity of 650 KHz/mmHg is described. These sensors will be related with their applications in harsh environment, distributed systems and medical environment, respectively. For many aspects, commercially available sensors, which in vast majority are piezoresistive, are not suited for the applications proposed.

Experimental Study on Basic Mechanical Properties of BFRP Bars

NASA Astrophysics Data System (ADS)

Fan, Xiaochun; Xu, Ting; Zhou, Zhengrong; Zhou, Xun

2017-10-01

Basalt Fiber Reinforced Polymer (BFRP) bars have the advantages of corrosion resistance, high strength, light weight, good dielectric properties, and they are new type of green reinforced alternative material. In order to determine the mechanical properties of BFRP bars, the tensile strength of basalt fiber bars was necessary to be studied. The diameters of the basalt fiber bars were compared by means of uniaxial tensile test in this article. Then the stress-strain curve can be drawn out. The results show that the stress - strain curve of BFRP bars present straight line relation, and there is no sign before failure; there is no yield platform on the stress-strain curve of BFRP bars, which are typical brittle material;the tensile strength of BFRP bars is about 3 times higher than that of ordinary steel bars. and the elastic modulus is about 1/5 of that of ordinary steel; the ultimate tensile strength of BFRP bars varies little with the increase of diameter, but there exist some differences in modulus values.

Compressed-air work is entering the field of high pressures.

PubMed

Le Péchon, J Cl; Gourdon, G

2010-01-01

Since 1850, compressed-air work has been used to prevent shafts or tunnels under construction from flooding. Until the 1980s, workers were digging in compressed-air environments. Since the introduction of tunnel boring machines (TBMs), very little digging under pressure is needed. However, the wearing out of cutter-head tools requires inspection and repair. Compressed-air workers enter the pressurized working chamber only occasionally to perform such repairs. Pressures between 3.5 and 4.5 bar, that stand outside a reasonable range for air breathing, were reached by 2002. Offshore deep diving technology had to be adapted to TBM work. Several sites have used mixed gases: in Japan for deep shaft sinking (4.8 bar), in The Netherlands at Western Scheldt Tunnels (6.9 bar), in Russia for St. Petersburg Metro (5.8 bar) and in the United States at Seattle (5.8 bar). Several tunnel projects are in progress that may involve higher pressures: Hallandsås (Sweden) interventions in heliox saturation up to 13 bar, and Lake Mead (U.S.) interventions to about 12 bar (2010). Research on TBMs and grouting technologies tries to reduce the requirements for hyperbaric works. Adapted international rules, expertise and services for saturation work, shuttles and trained personnel matching industrial requirements are the challenges.

An experimental study of unsteady sprays at very high injection pressures

NASA Astrophysics Data System (ADS)

Reggiori, A.; Mariani, F.; Parigi, G.; Carlevaro, R.

An experimental study of the development of fuel sprays under very high injection pressures is described. A gas gun capable of generating pressure pulses up to 10,000 bar has been employed as an injection pump. Tests have been carried out with simple cylindrical nozzles, injecting diesel oil in ambient air. The development of the jet has been visualized by means of flash shadowgraphy.

Novel Designs for Application Specific MEMS Pressure Sensors

PubMed Central

Fragiacomo, Giulio; Reck, Kasper; Lorenzen, Lasse; Thomsen, Erik V.

2010-01-01

In the framework of developing innovative microfabricated pressure sensors, we present here three designs based on different readout principles, each one tailored for a specific application. A touch mode capacitive pressure sensor with high sensitivity (14 pF/bar), low temperature dependence and high capacitive output signal (more than 100 pF) is depicted. An optical pressure sensor intrinsically immune to electromagnetic interference, with large pressure range (0–350 bar) and a sensitivity of 1 pm/bar is presented. Finally, a resonating wireless pressure sensor power source free with a sensitivity of 650 KHz/mmHg is described. These sensors will be related with their applications in harsh environment, distributed systems and medical environment, respectively. For many aspects, commercially available sensors, which in vast majority are piezoresistive, are not suited for the applications proposed. PMID:22163425

Classification of spray nozzles based on droplet size distributions and wind tunnel tests.

PubMed

De Schamphelerie, M; Spanoghe, P; Nuyttens, D; Baetens, K; Cornelis, W; Gabriels, D; Van der Meeren, P

2006-01-01

Droplet size distribution of a pesticide spray is recognised as a main factor affecting spray drift. As a first approximation, nozzles can be classified based on their droplet size spectrum. However, the risk of drift for a given droplet size distribution is also a function of spray structure, droplet velocities and entrained air conditions. Wind tunnel tests to determine actual drift potentials of the different nozzles have been proposed as a method of adding an indication of the risk of spray drift to the existing classification based on droplet size distributions (Miller et al, 1995). In this research wind tunnel tests were performed in the wind tunnel of the International Centre for Eremology (I.C.E.), Ghent University, to determine the drift potential of different types and sizes of nozzles at various spray pressures. Flat Fan (F) nozzles Hardi ISO 110 02, 110 03, 110 04, 110 06; Low-Drift (LD) nozzles Hardi ISO 110 02, 110 03, 110 04 and Injet Air Inclusion (AI) nozzles Hardi ISO 110 02, 110 03, 110 04 were tested at a spray pressures of 2, 3 and 4 bar. The droplet size spectra of the F and the LD nozzles were measured with a Malvern Mastersizer at spray pressures 2 bar, 3 bar and 4 bar. The Malvern spectra were used to calculate the Volume Median Diameters (VMD) of the sprays.

Stress-strain relationship of high-strength steel (HSS) reinforcing bars

NASA Astrophysics Data System (ADS)

Anggraini, Retno; Tavio, Raka, I. Gede Putu; Agustiar

2018-05-01

The introduction of High-Strength Steel (HSS) reinforcing bars in reinforced concrete members has gained much attention in recent years and led to many advantages such as construction timesaving. It is also more economical since it can reduce the amount of reinforcing steel bars used in concrete members which in turn alleviates the congestion of reinforcement. Up to present, the building codes, e.g. American Concrete Institute (ACI) 318M-14 and Standard National Indonesia (SNI) 2847:2013, still restrict the use of higher-strength steel reinforcing bars for concrete design up to Grade 420 MPa due to the possible suspected brittle behavior of concrete members. This paper evaluates the characteristics of stress-strain relationships of HSS bars if they are comparable to the characteristics of those of Grade 420 MPa. To achieve the objective of the study, a series of steel bars from various grades (420, 550, 650, and 700 MPa) was selected. Tensile tests of these steel samples were conducted under displacement-controlled mode to capture the complete stress-strain curves and particularly the post-yield response of the steel bars. The results indicate that all the steel bars tested had the actual yield strengths greater than the corresponding specified values. The stress-strain curves of HSS reinforcing bars (Grade 550, 650, and 700 MPa) performed slightly different characteristics with those of Grade 420 MPa.

Fatigue Behavior of Glass Fiber-Reinforced Polymer Bars after Elevated Temperatures Exposure.

PubMed

Li, Guanghui; Zhao, Jun; Wang, Zike

2018-06-16

Fiber-reinforced polymer (FRP) bars have been widely applied in civil engineering. This paper presents the results of an experimental study to investigate the tensile fatigue mechanical properties of glass fiber-reinforced polymer (GFRP) bars after elevated temperatures exposure. For this purpose, a total of 105 GFRP bars were conducted for testing. The specimens were exposed to heating regimes of 100, 150, 200, 250, 300 and 350 °C for a period of 0, 1 or 2 h. The GFRP bars were tested with different times of cyclic load after elevated temperatures exposure. The results show that the tensile strength and elastic modulus of GFRP bars decrease with the increase of elevated temperature and holding time, and the tensile strength of GFRP bars decreases obviously by 19.5% when the temperature reaches 250 °C. Within the test temperature range, the tensile strength of GFRP bars decreases at most by 28.0%. The cyclic load accelerates the degradation of GFRP bars after elevated temperature exposure. The coupling of elevated temperature and holding time enhance the degradation effect of cyclic load on GFRP bars. The tensile strength of GFRP bars after elevated temperatures exposure at 350 °C under cyclic load is reduced by 50.5% compared with that at room temperature and by 36.3% compared with that after exposing at 350 °C without cyclic load. In addition, the elastic modulus of GFRP bars after elevated temperatures exposure at 350 °C under cyclic load is reduced by 17.6% compared with that at room temperature and by 6.0% compared with that after exposing at 350 °C without cyclic load.

Energy Systems High-Pressure Test Laboratory | Energy Systems Integration

Science.gov Websites

Facility | NREL Energy Systems High-Pressure Test Laboratory Energy Systems High-Pressure Test Laboratory In the Energy Systems Integration Facility's High-Pressure Test Laboratory, researchers can safely test high-pressure hydrogen components. Photo of researchers running an experiment with a hydrogen fuel

Washing with contaminated bar soap is unlikely to transfer bacteria.

PubMed Central

Heinze, J. E.; Yackovich, F.

1988-01-01

Recent reports of the isolation of microorganisms from used soap bars have raised the concern that bacteria may be transferred from contaminated soap bars during handwashing. Since only one study addressing this question has been published, we developed an additional procedure to test this concern. In our new method prewashed and softened commercial deodorant soap bars (0.8% triclocarban) not active against Gram-negative bacteria were inoculated with Escherichia coli and Pseudomonas aeruginosa to give mean total survival levels of 4.4 X 10(5) c.f.u. per bar which was 70-fold higher than those reported on used soap bars. Sixteen panelists were instructed to wash with the inoculated bars using their normal handwashing procedure. After washing, none of the 16 panelists had detectable levels of either test bacterium on their hands. Thus, the results obtained using our new method were in complete agreement with those obtained with the previously published method even though the two methods differ in a number of procedural aspects. These findings, along with other published reports, show that little hazard exists in routine handwashing with previously used soap bars and support the frequent use of soap and water for handwashing to prevent the spread of disease. PMID:3402545

Metal/polymer composite Nuss bar for minimally invasive bar removal after Pectus Excavatum treatment: FEM simulations.

PubMed

Ricotti, Leonardo; Ciuti, Gastone; Ghionzoli, Marco; Messineo, Antonio; Menciassi, Arianna

2014-12-01

This study aims at assessing the mechanical behavior of a composite metal/polymer bar to be implanted in the retrosternal position, in order to correct chest wall deformities, such as Pectus Excavatum. A 300-mm-long, 12.7-mm-wide, and 3.5-mm-thick Nuss bar was considered, made of different metals and biodegradable polymers, fixed at its extremities, and with a constant force of 250 N applied on its center. Two different geometries for the metal elements to be embedded in the polymeric matrix were tested: in the former, thin metal sheets and in the latter, cylindrical metal reinforcing rods were considered. Finite element method simulation results are reported, in terms of maximum stress and strain of the bar. Furthermore, the maximum stress values obtained by varying metal sheet thickness or rod diameter (and therefore the volumetric percentage of metal within the matrix) for different material combinations are also shown; optimal configuration for the Pectus Excavatum treatment was finally identified for a composite Nuss bar. Copyright © 2014 John Wiley & Sons, Ltd.

The Carnegie-Irvine Galaxy Survey. V. Statistical Study of Bars and Buckled Bars

NASA Astrophysics Data System (ADS)

Li, Zhao-Yu; Ho, Luis C.; Barth, Aaron J.

2017-08-01

Simulations have shown that bars are subject to a vertical buckling instability that transforms thin bars into boxy or peanut-shaped structures, but the physical conditions necessary for buckling to occur are not fully understood. We use the large sample of local disk galaxies in the Carnegie-Irvine Galaxy Survey to examine the incidence of bars and buckled bars across the Hubble sequence. Depending on the disk inclination angle (I), a buckled bar reveals itself as either a boxy/peanut-shaped bulge (at high I) or as a barlens structure (at low I). We visually identify bars, boxy/peanut-shaped bulges, and barlenses, and examine the dependence of bar and buckled bar fractions on host galaxy properties, including Hubble type, stellar mass, color, and gas mass fraction. We find that the barred and unbarred disks show similar distributions in these physical parameters. The bar fraction is higher (70%-80%) in late-type disks with low stellar mass (M * < 1010.5 M ⊙) and high gas mass ratio. In contrast, the buckled bar fraction increases to 80% toward massive and early-type disks (M * > 1010.5 M ⊙), and decreases with higher gas mass ratio. These results suggest that bars are more difficult to grow in massive disks that are dynamically hotter than low-mass disks. However, once a bar forms, it can easily buckle in the massive disks, where a deeper potential can sustain the vertical resonant orbits. We also find a probable buckling bar candidate (ESO 506-G004) that could provide further clues to understand the timescale of the buckling process.

49 CFR 178.347-5 - Pressure and leakage test.

Code of Federal Regulations, 2013 CFR

2013-10-01

... Specifications for Containers for Motor Vehicle Transportation § 178.347-5 Pressure and leakage test. (a) Each cargo tank must be tested in accordance with § 178.345-13 and this section. (b) Pressure test. Test... pressure must be 40 psig or 1.5 times tank MAWP, whichever is greater, and the inspection pressure is tank...

49 CFR 178.347-5 - Pressure and leakage test.

Code of Federal Regulations, 2011 CFR

2011-10-01

... Specifications for Containers for Motor Vehicle Transportation § 178.347-5 Pressure and leakage test. (a) Each cargo tank must be tested in accordance with § 178.345-13 and this section. (b) Pressure test. Test... pressure must be 40 psig or 1.5 times tank MAWP, whichever is greater, and the inspection pressure is tank...

49 CFR 178.347-5 - Pressure and leakage test.

Code of Federal Regulations, 2014 CFR

2014-10-01

... Specifications for Containers for Motor Vehicle Transportation § 178.347-5 Pressure and leakage test. (a) Each cargo tank must be tested in accordance with § 178.345-13 and this section. (b) Pressure test. Test... pressure must be 40 psig or 1.5 times tank MAWP, whichever is greater, and the inspection pressure is tank...

49 CFR 178.347-5 - Pressure and leakage test.

Code of Federal Regulations, 2012 CFR

2012-10-01

... Specifications for Containers for Motor Vehicle Transportation § 178.347-5 Pressure and leakage test. (a) Each cargo tank must be tested in accordance with § 178.345-13 and this section. (b) Pressure test. Test... pressure must be 40 psig or 1.5 times tank MAWP, whichever is greater, and the inspection pressure is tank...

Enabling Narrow(est) IWA Coronagraphy with STIS BAR5 and BAR10 Occulters

NASA Astrophysics Data System (ADS)

Schneider, Glenn; Gaspar, Andras; Debes, John; Gull, Theodore; Hines, Dean; Apai, Daniel; Rieke, George

2017-09-01

The Space Telescope Imaging Spectrograph's (STIS) BAR5 coronagraphic occulter was designed to provide high-contrast, visible-light, imaging in close (> 0.15") angular proximity to bright point-sources. We explored and verified the functionality and utility of the BAR5 occulter. We also investigated, and herein report on, the use of the BAR10 rounded corners as narrow-angle occulters and compare IWA vs. contrast performance for the BAR5, BAR10, and Wedge occulters. With that, we provide recommendations for the most efficacious BAR5 and BAR10 use on-orbit in support of GO science.

Comparison of vertical hydraulic conductivity in a streambed-point bar system of a gaining stream

NASA Astrophysics Data System (ADS)

Dong, Weihong; Chen, Xunhong; Wang, Zhaowei; Ou, Gengxin; Liu, Can

2012-07-01

SummaryVertical hydraulic conductivities (Kv) of both streambed and point bars can influence water and solute exchange between streams and surrounding groundwater systems. The sediments in point bars are relatively young compared to the older sediments in the adjacent aquifers but slightly older compared to submerged streambeds. Thus, the permeability in point bar sediments can be different not only from regional aquifer but also from modern streambed. However, there is a lack of detailed studies that document spatial variability of vertical hydraulic conductivity in point bars of meandering streams. In this study, the authors proposed an in situ permeameter test method to measure vertical hydraulic conductivity of the two point bars in Clear Creek, Nebraska, USA. We compared the Kv values in streambed and adjacent point bars through 45 test locations in the two point bars and 51 test locations in the streambed. The Kv values in the point bars were lower than those in the streambed. Kruskal-Wallis test confirmed that the Kv values from the point bars and from the channel came from two statistically different populations. Within a point bar, the Kv values were higher along the point bar edges than those from inner point bars. Grain size analysis indicated that slightly more silt and clay particles existed in sediments from inner point bars, compared to that from streambed and from locations near the point bar edges. While point bars are the deposits of the adjacent channel, the comparison of two groups of Kv values suggests that post-depositional processes had an effect on the evolution of Kv from channel to point bars in fluvial deposits. We believed that the transport of fine particles and the gas ebullition in this gaining stream had significant effects on the distribution of Kv values in a streambed-point bar system. With the ageing of deposition in a floodplain, the permeability of point bar sediments can likely decrease due to reduced effects of the upward

Bar Evolution and Bar Properties from Disc Galaxies in the Early Universe

NASA Astrophysics Data System (ADS)

Hutchinson-Smith, Tenley; Simmons, Brooke

2017-01-01

Bars in disc galaxies indicate a large collection of stars in a specific configuration of orbits that give the galaxy center a rectangular looking feature. Astronomers have discovered that these bars affect the distribution of matter in galaxies, and are also related to galaxy stellar mass and star formation history. Little is known about the specifics of how bars evolve and drive the evolution of their host galaxies because only a handful of bars have been studied in detail so far. I have examined a sample of 8,221 barred galaxies from the early universe to identify and examine correlations with galaxy properties. The data comes from Galaxy Zoo, an online citizen science project that allows anyone to classify and measure detailed properties of galaxies. I present results including the fraction of galaxies in the sample that have bars, and the variation of galaxy properties with bar length, including galaxy color and stellar mass. I also compare these results to barred galaxies in the local universe. I will discuss the implications of these results in the context of galaxy evolution overall, including the effect of dark matter on bars and galaxy evolution.

Behaviour of axially and eccentrically loaded short columns reinforced with GFRP bars

NASA Astrophysics Data System (ADS)

Sreenath, S.; Balaji, S.; Saravana Raja Mohan, K.

2017-07-01

The corrosion of steel reinforcing bars is a predominant factor in limiting the life expectancy of Reinforced Cement Concrete (RCC) structures. Corrosion resistant Fibre Reinforced Polymer (FRP) bars can be an effective alternative to steel bars in this context. Recent investigations reported the flexural behaviour of RCC beams reinforced with Glass Fibre Reinforced Polymer (GFRP) bars. This study is meant to investigate the suitability of Sand Coated GFRP reinforcement bars in short square columns which when loaded axially and loaded with a minimum eccentricity. Standard tests to assess mechanical properties of GFRP bars and pullout test to quantify the bond strength between the bars and concrete were conducted. GFRP reinforced column specimens with a cross-sectional dimension of 100mm X 100mm and of length 1000mm were cast and tested under axial and eccentric loading. The assessed load carrying capacity was compared with that of conventional steel reinforced columns of the same size. The yield load and ultimate load at failure withstood by the steel reinforced columns were considerably more than that of GFRP reinforced columns. The energy absorption capacity of GFRP reinforced columns was also poor compared to steel reinforced columns. Both the columns exhibited nearly the same ductile behaviour. Hence GFRP reinforcements are not recommendable for compression members.

Pressured HIV testing "in the name of love": a mixed methods analysis of pressured HIV testing among men who have sex with men in China.

PubMed

Ong, Jason J; Wu, Dan; Huang, Wenting; Fu, Hongyun; Desmond, Nicola; Ma, Wei; Kang, Dianmin; Liao, Meizhen; Marley, Gifty; Wei, Chongyi; Tang, Weiming; Liu, Chuncheng; Zhang, Ye; Pan, Stephen W; Yang, Bin; Yang, Ligang; Huang, Shujie; Tucker, Joseph D

2018-03-01

HIV testing has rapidly expanded into diverse, decentralized settings. While increasing accessibility to HIV testing is beneficial, it may lead to unintended consequences such as being pressured to test. We examined the frequency, correlates and contexts of pressured HIV testing among Chinese men who have sex with men (MSM) using mixed methods. We conducted an online survey of MSM (N = 1044) in May 2017. Pressured HIV testing was defined as being forced to test for HIV. We conducted logistic regression analysis to determine the associations between pressured HIV testing and socio-demographic and sexual behavioural factors. Follow-up interviews (n = 17) were conducted with men who reported pressured testing and we analysed qualitative data using a thematic analysis approach. Ninety-six men (9.2%) reported experiencing pressure to test for HIV. Regular male sex partners were the most common source of pressure (61%, 59/96), and the most common form of pressure was a threat to end a relationship with the one who was being pressured (39%, 37/96). We found a higher risk of pressured testing in men who had only used HIV self-testing compared to men who had never self-tested (AOR 2.39 (95%CI: 1.38 to 4.14)). However, this relationship was only significant among men with low education (AOR 5.88 (95% CI: 1.92 to 17.99)) and not among men with high education (AOR 1.62 (95% CI: 0.85 to 3.10)). After pressured testing, about half of men subsequently tested for HIV (55%, 53/96) without pressure - none reported being diagnosed with HIV. Consistent with this finding, qualitative data suggest that perceptions of pressure existed on a continuum and depended on the relationship status of the one who pressured them. Although being pressured to test was accompanied by negative feelings, men who were pressured into testing often changed their attitude towards HIV testing, testing behaviours, sexual behaviours and relationship with the one who pressured them to test. Pressured HIV

The Carnegie-Irvine Galaxy Survey. V. Statistical Study of Bars and Buckled Bars

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

Li, Zhao-Yu; Ho, Luis C.; Barth, Aaron J., E-mail: lizy@shao.ac.cn

Simulations have shown that bars are subject to a vertical buckling instability that transforms thin bars into boxy or peanut-shaped structures, but the physical conditions necessary for buckling to occur are not fully understood. We use the large sample of local disk galaxies in the Carnegie-Irvine Galaxy Survey to examine the incidence of bars and buckled bars across the Hubble sequence. Depending on the disk inclination angle ( i ), a buckled bar reveals itself as either a boxy/peanut-shaped bulge (at high i ) or as a barlens structure (at low i ). We visually identify bars, boxy/peanut-shaped bulges, andmore » barlenses, and examine the dependence of bar and buckled bar fractions on host galaxy properties, including Hubble type, stellar mass, color, and gas mass fraction. We find that the barred and unbarred disks show similar distributions in these physical parameters. The bar fraction is higher (70%–80%) in late-type disks with low stellar mass ( M {sub *} < 10{sup 10.5} M {sub ⊙}) and high gas mass ratio. In contrast, the buckled bar fraction increases to 80% toward massive and early-type disks ( M {sub *} > 10{sup 10.5} M {sub ⊙}), and decreases with higher gas mass ratio. These results suggest that bars are more difficult to grow in massive disks that are dynamically hotter than low-mass disks. However, once a bar forms, it can easily buckle in the massive disks, where a deeper potential can sustain the vertical resonant orbits. We also find a probable buckling bar candidate (ESO 506−G004) that could provide further clues to understand the timescale of the buckling process.« less

Propagation behavior of the stress wave in a hollow Hopkinson transmission bar

NASA Astrophysics Data System (ADS)

Zou, G.; Shen, X.; Guo, C.; Vecchio, K. S.; Jiang, F.

2018-03-01

In order to investigate the stress wave propagation behavior through a hollow elastic bar that is used in a Hopkinson-bar-loaded fracture testing system, three-point bending fracture experiments were performed in such a system. The effects of sample span and diameter and wall thickness of the hollow elastic bar on the stress wave propagation behavior were studied numerically using the software of ANSYS/LS-DYNA. The experimental results demonstrated that the incident, reflected, and transmitted pulses calculated by the finite element method are coincident with those obtained from the Hopkinson-bar-loaded fracture tests. Compared to the solid transmission bar, the amplitude of the transmitted pulse is relatively larger in the hollow transmission bar under the same loading conditions and decreases with increasing wall thickness. On the other hand, when the inside diameter is fixed, the effect of the wall thickness on the stress wave characteristics is more obvious.

Leaf water potentials measured with a pressure chamber.

PubMed

Boyer, J S

1967-01-01

Leaf water potentials were estimated from the sum of the balancing pressure measured with a pressure chamber and the osmotic potential of the xylem sap in leafy shoots or leaves. When leaf water potentials in yew, rhododendron, and sunflower were compared with those measured with a thermocouple psychrometer known to indicate accurate values of leaf water potential, determinations were within +/- 2 bars of the psychrometer measurements with sunflower and yew. In rhododendron. water potentials measured with the pressure chamber plus xylem sap were 2.5 bars less negative to 4 bars more negative than psychrometer measurements.The discrepancies in the rhododendron measurements could be attributed, at least in part, to the filling of tissues other than xylem with xylem sap during measurements with the pressure chamber. It was concluded that, although stem characteristics may affect the measurements, pressure chamber determinations were sufficiently close to psychrometer measurements that the pressure chamber may be used for relative measurements of leaf water potentials, especially in sunflower and yew. For accurate determinations of leaf water potential, however, pressure chamber measurements must be calibrated with a thermocouple psychrometer.

Self-Pressurization and Spray Cooling Simulations of the Multipurpose Hydrogen Test Bed (MHTB) Ground-Based Experiment

NASA Technical Reports Server (NTRS)

Kartuzova, O.; Kassemi, M.; Agui, J.; Moder, J.

2014-01-01

This paper presents a CFD (computational fluid dynamics) model for simulating the self-pressurization of a large scale liquid hydrogen storage tank. In this model, the kinetics-based Schrage equation is used to account for the evaporative and condensing interfacial mass flows. Laminar and turbulent approaches to modeling natural convection in the tank and heat and mass transfer at the interface are compared. The flow, temperature, and interfacial mass fluxes predicted by these two approaches during tank self-pressurization are compared against each other. The ullage pressure and vapor temperature evolutions are also compared against experimental data obtained from the MHTB (Multipuprpose Hydrogen Test Bed) self-pressurization experiment. A CFD model for cooling cryogenic storage tanks by spraying cold liquid in the ullage is also presented. The Euler- Lagrange approach is utilized for tracking the spray droplets and for modeling interaction between the droplets and the continuous phase (ullage). The spray model is coupled with the VOF (volume of fluid) model by performing particle tracking in the ullage, removing particles from the ullage when they reach the interface, and then adding their contributions to the liquid. Droplet ullage heat and mass transfer are modeled. The flow, temperature, and interfacial mass flux predicted by the model are presented. The ullage pressure is compared with experimental data obtained from the MHTB spray bar mixing experiment. The results of the models with only droplet/ullage heat transfer and with heat and mass transfer between the droplets and ullage are compared.

Portable fixture facilitates pressure testing of instrumentation fittings

NASA Technical Reports Server (NTRS)

Olson, G. A.

1967-01-01

Portable fixture facilitates pressure testing to detect possible leaks in instrumentation fittings mounted on tank bulkheads. It uses a vacuum cup which seals a pressure regulator adapter around one side of the fitting to be pressure tested. Leakage is detected with a gas sniffer.

Testing of selected metallic reinforcing bars for extending the service life of future concrete bridges : testing in outdoor concrete blocks.

DOT National Transportation Integrated Search

2002-01-01

To meet the challenge of a design life of 100 years for major concrete bridges, economical and corrosion-resistant reinforcing bars will be needed. The preliminary results for stainless steel-clad bars in a recent investigation funded by the Federal ...

Studying W‧ boson contributions in \\bar{B} \\rightarrow {D}^{(* )}{{\\ell }}^{-}{\\bar{\

NASA Astrophysics Data System (ADS)

Wang, Yi-Long; Wei, Bin; Sheng, Jin-Huan; Wang, Ru-Min; Yang, Ya-Dong

2018-05-01

Recently, the Belle collaboration reported the first measurement of the τ lepton polarization P τ (D*) in \\bar{B}\\to {D}* {τ }-{\\bar{ν }}τ decay and a new measurement of the rate of the branching ratios R(D*), which are consistent with the Standard Model (SM) predictions. These could be used to constrain the New Physics (NP) beyond the SM. In this paper, we probe \\bar{B}\\to {D}(* ){{\\ell }}-{\\bar{ν }}{\\ell } (ℓ = e, μ, τ) decays in the model-independent way and in the specific G(221) models with lepton flavour universality. Considering the theoretical uncertainties and the experimental errors at the 95% C.L., we obtain the quite strong bounds on the model-independent parameters {C}{{LL}}{\\prime },{C}{{LR}}{\\prime },{C}{{RR}}{\\prime },{C}{{RL}}{\\prime },{g}V,{g}A,{g}V{\\prime },{g}A{\\prime } and the specific G(221) model parameter rates. We find that the constrained NP couplings have no obvious effects on all (differential) branching ratios and their rates, nevertheless, many NP couplings have very large effects on the lepton spin asymmetries of \\bar{B}\\to {D}(* ){{\\ell }}-{\\bar{ν }}{\\ell } decays and the forward–backward asymmetries of \\bar{B}\\to {D}* {{\\ell }}-{\\bar{ν }}{\\ell }. So we expect precision measurements of these observables would be researched by LHCb and Belle-II.

The influence of main bar corrosion on bond strength in selfcompacting concrete

NASA Astrophysics Data System (ADS)

Ayop, S. S.; Emhemed, A. N. K.; Jamaluddin, N.; Sadikin, A.

2017-11-01

The experimental study was conducted to determine the influence of main bar corrosion on bond strength in self-compacting concrete (SCC). A total 16 tension pullout tests specimens reinforced with 10 mm and 14 mm diameter bar were used for the bond strength test. The properties of SCC were determined from the slump flow, T50cm, V-funnel and L box test. Reinforcing bars in the concrete were submitted to impressed current to accelerate the corrosion of the bar. It was found that the relationship between bond strength and concrete strength in un-corroded specimens differed from that of corroded specimens set in high-strength concrete because of brittleness in the corroded specimens, which caused a sudden loss of bond strength. The results revealed that specimens of un-corroded and corroded showed a higher percentage of bond strength degradation during the pullout tests.

Icing research tunnel rotating bar calibration measurement system

NASA Technical Reports Server (NTRS)

Gibson, Theresa L.; Dearmon, John M.

1993-01-01

In order to measure icing patterns across a test section of the Icing Research Tunnel, an automated rotating bar measurement system was developed at the NASA Lewis Research Center. In comparison with the previously used manual measurement system, this system provides a number of improvements: increased accuracy and repeatability, increased number of data points, reduced tunnel operating time, and improved documentation. The automated system uses a linear variable differential transformer (LVDT) to measure ice accretion. This instrument is driven along the bar by means of an intelligent stepper motor which also controls data recording. This paper describes the rotating bar calibration measurement system.

Nutritional Evaluation of NASA's Rodent Food Bar Diet

NASA Technical Reports Server (NTRS)

Barrett, Joyce E.; Yu, Diane S.; Dalton, Bonnie P.

2000-01-01

Tests are being conducted on NASA's rodent Food Bar in preparation for long-term use as the rat and mouse diet aboard the International Space Station. Nutritional analyses are performed after the bars are manufactured and then repeated periodically to determine nutritional stability. The primary factors analyzed are protein, ash, fat, fiber, moisture, amino acids, fatty acids, and minerals. Nutrient levels are compared to values published in the National Research Council's dietary requirements for rodents, and also to those contained in several commonly used commercial rodent lab diets. The Food Bar is manufactured from a powdered diet to which moisture is added as it is processed through an extruder. The bars are dipped into potassium sorbate, vacuum-sealed, and irradiated. In order to determine nutrient changes during extrusion and irradiation, the powdered diet, the non-irradiated bars, and the irradiated bars are all analyzed. We have observed lower values for some nutrients (iodine, vitamin K, and iron) in the Food Bars compared with NRC requirements. Many nutrients in the Food Bars are contained at a higher level than levels in the NRC requirements. An additional factor we are investigating is the 26% moisture level in the Food Bars, which drops to about 15% within a week, compared to a stable 10% moisture in many standard lab chow diets. In addition to the nutritional analyses, the food bar is being fed to several strains of rats and mice, and feeding study and necropsy results are being observed (Barrett et al, unpublished data). Information from the nutritional analyses and from the rodent studies will enable us to recommend the formulation that will most adequately meet the rodent Food Bar requirements for long-term use aboard the Space Station.

Flight testing of a luminescent surface pressure sensor

NASA Technical Reports Server (NTRS)

Mclachlan, B. G.; Bell, J. H.; Espina, J.; Gallery, J.; Gouterman, M.; Demandante, C. G. N.; Bjarke, L.

1992-01-01

NASA ARC has conducted flight tests of a new type of aerodynamic pressure sensor based on a luminescent surface coating. Flights were conducted at the NASA ARC-Dryden Flight Research Facility. The luminescent pressure sensor is based on a surface coating which, when illuminated with ultraviolet light, emits visible light with an intensity dependent on the local air pressure on the surface. This technique makes it possible to obtain pressure data over the entire surface of an aircraft, as opposed to conventional instrumentation, which can only make measurements at pre-selected points. The objective of the flight tests was to evaluate the effectiveness and practicality of a luminescent pressure sensor in the actual flight environment. A luminescent pressure sensor was installed on a fin, the Flight Test Fixture (FTF), that is attached to the underside of an F-104 aircraft. The response of one particular surface coating was evaluated at low supersonic Mach numbers (M = 1.0-1.6) in order to provide an initial estimate of the sensor's capabilities. This memo describes the test approach, the techniques used, and the pressure sensor's behavior under flight conditions. A direct comparison between data provided by the luminescent pressure sensor and that produced by conventional pressure instrumentation shows that the luminescent sensor can provide quantitative data under flight conditions. However, the test results also show that the sensor has a number of limitations which must be addressed if this technique is to prove useful in the flight environment.

An Insertable Passive LC Pressure Sensor Based on an Alumina Ceramic for In Situ Pressure Sensing in High-Temperature Environments.

PubMed

Xiong, Jijun; Li, Chen; Jia, Pinggang; Chen, Xiaoyong; Zhang, Wendong; Liu, Jun; Xue, Chenyang; Tan, Qiulin

2015-08-31

Pressure measurements in high-temperature applications, including compressors, turbines, and others, have become increasingly critical. This paper proposes an implantable passive LC pressure sensor based on an alumina ceramic material for in situ pressure sensing in high-temperature environments. The inductance and capacitance elements of the sensor were designed independently and separated by a thermally insulating material, which is conducive to reducing the influence of the temperature on the inductance element and improving the quality factor of the sensor. In addition, the sensor was fabricated using thick film integrated technology from high-temperature materials that ensure stable operation of the sensor in high-temperature environments. Experimental results showed that the sensor accurately monitored pressures from 0 bar to 2 bar at temperatures up to 800 °C. The sensitivity, linearity, repeatability error, and hysteretic error of the sensor were 0.225 MHz/bar, 95.3%, 5.5%, and 6.2%, respectively.

[Pressure control in medical gas distribution systems].

PubMed

Bourgain, J L; Benayoun, L; Baguenard, P; Haré, G; Puizillout, J M; Billard, V

1997-01-01

To assess whether the pressure gauges at the downstream part of pressure regulators are accurate enough to ensure that pressure in O2 pipeline is always higher than in Air pipeline and that pressure in the latter is higher than pressure in N2O pipeline. A pressure difference of at least 0.4 bar between two medical gas supply systems is recommended to avoid the reflow of either N2O or Air into the O2 pipeline, through a faulty mixer or proportioning device. Prospective technical comparative study. Readings of 32 Bourdon gauges were compared with data obtained with a calibrated reference transducer. Two sets of measurements were performed at a one month interval. Pressure differences between Bourdon gauges and reference transducer were 8% (0.28 bar) in average for a theoretical maximal error less than 2.5%. During the first set of measurements, Air pressure was higher than O2 pressure in one place and N2O pressure higher than Air pressure in another. After an increase in the O2 pipeline pressure and careful setting of pressure regulators, this problem was not observed at the second set of measurements. Actual accuracy of Bourdon gauges was not convenient enough to ensure that O2 pressure was always above Air pressure. Regular controls of these pressure gauges are therefore essential. Replacement of the faulty Bourdon gauges by more accurate transducers should be considered. As an alternative, the increase in pressure difference between O2 and Air pipelines to at least 0.6 bar is recommended.

ORION - Crew Module Side Hatch: Proof Pressure Test Anomaly Investigation

NASA Technical Reports Server (NTRS)

Evernden, Brent A.; Guzman, Oscar J.

2018-01-01

The Orion Multi-Purpose Crew Vehicle program was performing a proof pressure test on an engineering development unit (EDU) of the Orion Crew Module Side Hatch (CMSH) assembly. The purpose of the proof test was to demonstrate structural capability, with margin, at 1.5 times the maximum design pressure, before integrating the CMSH to the Orion Crew Module structural test article for subsequent pressure testing. The pressure test was performed at lower pressures of 3 psig, 10 psig and 15.75 psig with no apparent abnormal behavior or leaking. During pressurization to proof pressure of 23.32 psig, a loud 'pop' was heard at 21.3 psig. Upon review into the test cell, it was noted that the hatch had prematurely separated from the proof test fixture, thus immediately ending the test. The proof pressure test was expected be a simple verification but has since evolved into a significant joint failure investigation from both Lockheed Martin and NASA.

30 CFR 250.448 - What are the BOP pressure tests requirements?

Code of Federal Regulations, 2010 CFR

2010-07-01

... you pressure test the BOP system, you must conduct a low-pressure and a high-pressure test for each BOP component. You must conduct the low-pressure test before the high-pressure test. Each individual... zero and reinitiate the test. (b) High-pressure test for ram-type BOPs, the choke manifold, and other...

Dew-point measurements at high water vapour pressure

NASA Astrophysics Data System (ADS)

Lomperski, S.; Dreier, J.

1996-05-01

A dew-point meter capable of measuring humidity at high vapour pressure and high temperature has been constructed and tested. Humidity measurements in pure steam were made over the temperature range 100 - 1500957-0233/7/5/003/img1C and a vapour pressure range of 1 - 4 bar. The dew-point meter performance was assessed by comparing measurements with a pressure transmitter and agreement between the two was within 0957-0233/7/5/003/img2% relative humidity. Humidity measurements in steam - air mixtures were also made and the dew-point meter readings were compared to those of a zirconia oxygen sensor. For these tests the dew-point meter readings were generally within 0957-0233/7/5/003/img2% relative humidity of the oxygen sensor measurements.

49 CFR 178.348-5 - Pressure and leakage test.

Code of Federal Regulations, 2011 CFR

2011-10-01

... Specifications for Containers for Motor Vehicle Transportation § 178.348-5 Pressure and leakage test. (a) Each cargo tank must be tested in accordance with § 178.345-13 and this section. (b) Pressure test. Test..., and the inspection pressure is tank MAWP. [Amdt. 178-89, 54 FR 25032, June 12, 1989. Redesignated by...

49 CFR 178.348-5 - Pressure and leakage test.

Code of Federal Regulations, 2014 CFR

2014-10-01

... Specifications for Containers for Motor Vehicle Transportation § 178.348-5 Pressure and leakage test. (a) Each cargo tank must be tested in accordance with § 178.345-13 and this section. (b) Pressure test. Test..., and the inspection pressure is tank MAWP. [Amdt. 178-89, 54 FR 25032, June 12, 1989. Redesignated by...

49 CFR 178.348-5 - Pressure and leakage test.

Code of Federal Regulations, 2012 CFR

2012-10-01

... Specifications for Containers for Motor Vehicle Transportation § 178.348-5 Pressure and leakage test. (a) Each cargo tank must be tested in accordance with § 178.345-13 and this section. (b) Pressure test. Test..., and the inspection pressure is tank MAWP. [Amdt. 178-89, 54 FR 25032, June 12, 1989. Redesignated by...

49 CFR 178.348-5 - Pressure and leakage test.

Code of Federal Regulations, 2013 CFR

2013-10-01

... Specifications for Containers for Motor Vehicle Transportation § 178.348-5 Pressure and leakage test. (a) Each cargo tank must be tested in accordance with § 178.345-13 and this section. (b) Pressure test. Test..., and the inspection pressure is tank MAWP. [Amdt. 178-89, 54 FR 25032, June 12, 1989. Redesignated by...

Pressure-Sensitive Paints Advance Rotorcraft Design Testing

NASA Technical Reports Server (NTRS)

2013-01-01

The rotors of certain helicopters can spin at speeds as high as 500 revolutions per minute. As the blades slice through the air, they flex, moving into the wind and back out, experiencing pressure changes on the order of thousands of times a second and even higher. All of this makes acquiring a true understanding of rotorcraft aerodynamics a difficult task. A traditional means of acquiring aerodynamic data is to conduct wind tunnel tests using a vehicle model outfitted with pressure taps and other sensors. These sensors add significant costs to wind tunnel testing while only providing measurements at discrete locations on the model's surface. In addition, standard sensor solutions do not work for pulling data from a rotor in motion. "Typical static pressure instrumentation can't handle that," explains Neal Watkins, electronics engineer in Langley Research Center s Advanced Sensing and Optical Measurement Branch. "There are dynamic pressure taps, but your costs go up by a factor of five to ten if you use those. In addition, recovery of the pressure tap readings is accomplished through slip rings, which allow only a limited amount of sensors and can require significant maintenance throughout a typical rotor test." One alternative to sensor-based wind tunnel testing is pressure sensitive paint (PSP). A coating of a specialized paint containing luminescent material is applied to the model. When exposed to an LED or laser light source, the material glows. The glowing material tends to be reactive to oxygen, explains Watkins, which causes the glow to diminish. The more oxygen that is present (or the more air present, since oxygen exists in a fixed proportion in air), the less the painted surface glows. Imaged with a camera, the areas experiencing greater air pressure show up darker than areas of less pressure. "The paint allows for a global pressure map as opposed to specific points," says Watkins. With PSP, each pixel recorded by the camera becomes an optical pressure

Bar-Chart-Monitor System For Wind Tunnels

NASA Technical Reports Server (NTRS)

Jung, Oscar

1993-01-01

Real-time monitor system provides bar-chart displays of significant operating parameters developed for National Full-Scale Aerodynamic Complex at Ames Research Center. Designed to gather and process sensory data on operating conditions of wind tunnels and models, and displays data for test engineers and technicians concerned with safety and validation of operating conditions. Bar-chart video monitor displays data in as many as 50 channels at maximum update rate of 2 Hz in format facilitating quick interpretation.

49 CFR 178.346-5 - Pressure and leakage tests.

Code of Federal Regulations, 2012 CFR

2012-10-01

... must be the greater of 5.0 psig or 1.5 times the cargo tank MAWP, and the inspection pressure must be... Specifications for Containers for Motor Vehicle Transportation § 178.346-5 Pressure and leakage tests. (a) Each cargo tank must be tested in accordance with § 178.345-13 and this section. (b) Pressure test. Test...

49 CFR 178.346-5 - Pressure and leakage tests.

Code of Federal Regulations, 2011 CFR

2011-10-01

... must be the greater of 5.0 psig or 1.5 times the cargo tank MAWP, and the inspection pressure must be... Specifications for Containers for Motor Vehicle Transportation § 178.346-5 Pressure and leakage tests. (a) Each cargo tank must be tested in accordance with § 178.345-13 and this section. (b) Pressure test. Test...

49 CFR 178.346-5 - Pressure and leakage tests.

Code of Federal Regulations, 2014 CFR

2014-10-01

... must be the greater of 5.0 psig or 1.5 times the cargo tank MAWP, and the inspection pressure must be... Specifications for Containers for Motor Vehicle Transportation § 178.346-5 Pressure and leakage tests. (a) Each cargo tank must be tested in accordance with § 178.345-13 and this section. (b) Pressure test. Test...

49 CFR 178.346-5 - Pressure and leakage tests.

Code of Federal Regulations, 2013 CFR

2013-10-01

... must be the greater of 5.0 psig or 1.5 times the cargo tank MAWP, and the inspection pressure must be... Specifications for Containers for Motor Vehicle Transportation § 178.346-5 Pressure and leakage tests. (a) Each cargo tank must be tested in accordance with § 178.345-13 and this section. (b) Pressure test. Test...

Remotely operated high pressure valve protects test personnel

NASA Technical Reports Server (NTRS)

Howland, B. T.

1967-01-01

High pressure valve used in testing certain spacecraft systems is safely opened and closed by a remotely stationed operator. The valve is self-regulating in that if the incoming pressure drops below a desired value the valve will automatically close, warning the operator that the testing pressure has dropped to an undesired level.

Bar Code Labels

NASA Technical Reports Server (NTRS)

1988-01-01

American Bar Codes, Inc. developed special bar code labels for inventory control of space shuttle parts and other space system components. ABC labels are made in a company-developed anodizing aluminum process and consecutively marketed with bar code symbology and human readable numbers. They offer extreme abrasion resistance and indefinite resistance to ultraviolet radiation, capable of withstanding 700 degree temperatures without deterioration and up to 1400 degrees with special designs. They offer high resistance to salt spray, cleaning fluids and mild acids. ABC is now producing these bar code labels commercially or industrial customers who also need labels to resist harsh environments.

Infrared spectra of hexamethylbenzene—tetracyanoethylene complexes at high pressures

NASA Astrophysics Data System (ADS)

Yamada, Haruka; Saheki, Masao

Infrared spectra of hexamethylbenzene(HMB)—tetracyanoethylene(TCNE), 1:1 and 2:1, complexes were measured under high pressures, 11˜4,000 bar. It was found that the CC stretching (A g) band of TCNE became much stronger at high pressures than at 1 bar and that the intensity increase of this band was especially large for both of the complexes. Based on these facts the strong appearance of the CC band at 1 bar, which is inconsistent with the symmetry consideration derived from X-ray analysis, can be discussed.

Laboratory and Workplace Assessments of Rivet Bucking Bar Vibration Emissions

PubMed Central

McDowell, Thomas W.; Warren, Christopher; Xu, Xueyan S.; Welcome, Daniel E.; Dong, Ren G.

2016-01-01

Sheet metal workers operating rivet bucking bars are at risk of developing hand and wrist musculoskeletal disorders associated with exposures to hand-transmitted vibrations and forceful exertions required to operate these hand tools. New bucking bar technologies have been introduced in efforts to reduce workplace vibration exposures to these workers. However, the efficacy of these new bucking bar designs has not been well documented. While there are standardized laboratory-based methodologies for assessing the vibration emissions of many types of powered hand tools, no such standard exists for rivet bucking bars. Therefore, this study included the development of a laboratory-based method for assessing bucking bar vibrations which utilizes a simulated riveting task. With this method, this study evaluated three traditional steel bucking bars, three similarly shaped tungsten alloy bars, and three bars featuring spring-dampeners. For comparison the bucking bar vibrations were also assessed during three typical riveting tasks at a large aircraft maintenance facility. The bucking bars were rank-ordered in terms of unweighted and frequency-weighted acceleration measured at the hand-tool interface. The results suggest that the developed laboratory method is a reasonable technique for ranking bucking bar vibration emissions; the lab-based riveting simulations produced similar rankings to the workplace rankings. However, the laboratory-based acceleration averages were considerably lower than the workplace measurements. These observations suggest that the laboratory test results are acceptable for comparing and screening bucking bars, but the laboratory measurements should not be directly used for assessing the risk of workplace bucking bar vibration exposures. The newer bucking bar technologies exhibited significantly reduced vibrations compared to the traditional steel bars. The results of this study, together with other information such as rivet quality, productivity, tool

High Pressure Gas Permeation and Liquid Diffusion Studies of Coflon and Tefzel Thermoplastics. Revision

NASA Technical Reports Server (NTRS)

Morgan, G. J.; Campion, R. P.

1997-01-01

The life of fluid-carrying flexible or umbilical pipes during service at elevated temperatures and pressures depends inter alia on their resistance to attack by the fluids present and the rate at which these fluids are absorbed by the pipe lining materials. The consequences of fluid ingress into the thermoplastic lining could mean a) a reduction in its mechanical strength, to increase chances of crack formation and growth and thus a loss of integrity, b) the occurrence of permeation right through the lining material, with pressure build- up in the outer pipe wall construction (of flexible pipes) or chemical attack (from a hostile permeant) on outer layers of reinforcements. Therefore it is important within this project to have relevant permeation data for Coflon and Tefzel thermoplastics: the former is plasticised, the latter is not. A previous report (CAPP/M.2) described experimental equipment and techniques used by MERL when measuring high pressure (up to 5000 psi) gas permeation and liquid diffusion through thermoplastic samples cut from extruded bar or pipe, and provided the basic theory involved. Norsk Hydro are also performing gas permeation tests on pipe sections, at up to 100 bars (1450 psi) pressure or so, and reporting separately. Some comparisons between data from Norsk Hydro and MERL have been made herein. The tests should be considered as complementary, as the Norsk Hydro test has the obvious benefit of using complete pipe sections, whilst MERL can test at much higher pressures, up to 1000 bar if necessary. The sophisticated analytical measuring equipment of Norsk Hydro can distinguish the individual components of mixed gases and hence the various permeation-linked coefficients whereas MERL, in using pressure increase at constant volume to determine permeation rate, is limited to obtaining single gas data, or apparent (or representative) coefficients for a mixed gas as a whole. Except for the initial fluid diffusion data for Tefzel described in CAPP

The bridge technique for pectus bar fixation: a method to make the bar un-rotatable.

PubMed

Park, Hyung Joo; Kim, Kyung Soo; Moon, Young Kyu; Lee, Sungsoo

2015-08-01

Pectus bar rotation is a major challenge in pectus repair. However, to date, no satisfactory technique to completely eliminate bar displacement has been introduced. Here, we propose a bar fixation technique using a bridge that makes the bar unmovable. The purpose of this study was to determine the efficacy of this bridge technique. A total of 80 patients underwent pectus bar repair of pectus excavatum with the bridge technique from July 2013 to July 2014. The technique involved connecting 2 parallel bars using plate-screws at the ends of the bars. To determine bar position change, the angles between the sternum and pectus bars were measured on postoperative day 5 (POD5) and 4 months (POM4) and compared. The mean patient age was 17.5 years (range, 6-38 years). The mean difference between POD5 and POM4 were 0.23° (P=.602) and 0.35° (P=.338) for the upper and lower bars, respectively. Bar position was virtually unchanged during the follow-up, and there was no bar dislocation or reoperation. A "bridge technique" designed to connect 2 parallel bars using plates and screws was demonstrated as a method to avoid pectus bar displacement. This approach was easy to implement without using sutures or invasive devices. Copyright © 2015 Elsevier Inc. All rights reserved.

Leaf Water Potentials Measured with a Pressure Chamber

PubMed Central

Boyer, J. S.

1967-01-01

Leaf water potentials were estimated from the sum of the balancing pressure measured with a pressure chamber and the osmotic potential of the xylem sap in leafy shoots or leaves. When leaf water potentials in yew, rhododendron, and sunflower were compared with those measured with a thermocouple psychrometer known to indicate accurate values of leaf water potential, determinations were within ± 2 bars of the psychrometer measurements with sunflower and yew. In rhododendron. water potentials measured with the pressure chamber plus xylem sap were 2.5 bars less negative to 4 bars more negative than psychrometer measurements. The discrepancies in the rhododendron measurements could be attributed, at least in part, to the filling of tissues other than xylem with xylem sap during measurements with the pressure chamber. It was concluded that, although stem characteristics may affect the measurements, pressure chamber determinations were sufficiently close to psychrometer measurements that the pressure chamber may be used for relative measurements of leaf water potentials, especially in sunflower and yew. For accurate determinations of leaf water potential, however, pressure chamber measurements must be calibrated with a thermocouple psychrometer. PMID:16656476

Linking morphology and motion: a test of a four-bar mechanism in seahorses.

PubMed

Roos, Gert; Leysen, Heleen; Van Wassenbergh, Sam; Herrel, Anthony; Jacobs, Patric; Dierick, Manuel; Aerts, Peter; Adriaens, Dominique

2009-01-01

Syngnathid fishes (seahorses, pipefish, and sea dragons) possess a highly modified cranium characterized by a long and tubular snout with minute jaws at its end. Previous studies indicated that these species are extremely fast suction feeders with their feeding strike characterized by a rapid elevation of the head accompanied by rotation of the hyoid. A planar four-bar model is proposed to explain the coupled motion of the neurocranium and the hyoid. Because neurocranial elevation as well as hyoid rotation are crucial for the feeding mechanism in previously studied Syngnathidae, a detailed evaluation of this model is needed. In this study, we present kinematic data of the feeding strike in the seahorse Hippocampus reidi. We combined these data with a detailed morphological analysis of the important linkages and joints involved in rotation of the neurocranium and the hyoid, and we compared the kinematic measurements with output of a theoretical four-bar model. The kinematic analysis shows that neurocranial rotation never preceded hyoid rotation, thus indicating that hyoid rotation triggers the explosive feeding strike. Our data suggest that while neurocranium and hyoid initially (first 1.5 ms) behave as predicted by the four-bar model, eventually, the hyoid rotation is underestimated by the model. Shortening, or a posterior displacement of the sternohyoid muscle (of which the posterior end is confluent with the hypaxial muscles in H. reidi), probably explains the discrepancy between the model and our kinematic measurements. As a result, while four-bar modeling indicates a clear coupling between hyoid rotation and neurocranial elevation, the detailed morphological determination of the linkages and joints of this four-bar model remain crucial in order to fully understand this mechanism in seahorse feeding.

An Insertable Passive LC Pressure Sensor Based on an Alumina Ceramic for In Situ Pressure Sensing in High-Temperature Environments

PubMed Central

Xiong, Jijun; Li, Chen; Jia, Pinggang; Chen, Xiaoyong; Zhang, Wendong; Liu, Jun; Xue, Chenyang; Tan, Qiulin

2015-01-01

Pressure measurements in high-temperature applications, including compressors, turbines, and others, have become increasingly critical. This paper proposes an implantable passive LC pressure sensor based on an alumina ceramic material for in situ pressure sensing in high-temperature environments. The inductance and capacitance elements of the sensor were designed independently and separated by a thermally insulating material, which is conducive to reducing the influence of the temperature on the inductance element and improving the quality factor of the sensor. In addition, the sensor was fabricated using thick film integrated technology from high-temperature materials that ensure stable operation of the sensor in high-temperature environments. Experimental results showed that the sensor accurately monitored pressures from 0 bar to 2 bar at temperatures up to 800 °C. The sensitivity, linearity, repeatability error, and hysteretic error of the sensor were 0.225 MHz/bar, 95.3%, 5.5%, and 6.2%, respectively. PMID:26334279

Impact of hydrostatic pressure on an intrinsically disordered protein: a high-pressure NMR study of α-synuclein.

PubMed

Roche, Julien; Ying, Jinfa; Maltsev, Alexander S; Bax, Ad

2013-09-23

The impact of pressure on the backbone (15) N, (1) H and (13) C chemical shifts in N-terminally acetylated α-synuclein has been evaluated over a pressure range 1-2500 bar. Even while the chemical shifts fall very close to random coil values, as expected for an intrinsically disordered protein, substantial deviations in the pressure dependence of the chemical shifts are seen relative to those in short model peptides. In particular, the nonlinear pressure response of the (1) H(N) chemical shifts, which commonly is associated with the presence of low-lying "excited states", is much larger in α-synuclein than in model peptides. The linear pressure response of (1) H(N) chemical shift, commonly linked to H-bond length change, correlates well with those in short model peptides, and is found to be anticorrelated with its temperature dependence. The pressure dependence of (13) C chemical shifts shows remarkably large variations, even when accounting for residue type, and do not point to a clear shift in population between different regions of the Ramachandran map. However, a nearly universal decrease in (3) JHN-Hα by 0.22 ± 0.05 Hz suggests a slight increase in population of the polyproline II region at 2500 bar. The first six residues of N-terminally acetylated synuclein show a transient of approximately 15% population of α-helix, which slightly diminishes at 2500 bar. The backbone dynamics of the protein is not visibly affected beyond the effect of slight increase in water viscosity at 2500 bar. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Orion ECLSS/Suit System - Ambient Pressure Integrated Suit Test

NASA Technical Reports Server (NTRS)

Barido, Richard A.

2012-01-01

The Ambient Pressure Integrated Suit Test (APIST) phase of the integrated system testing of the Orion Vehicle Atmosphere Revitalization System (ARS) technology was conducted for the Multipurpose Crew Vehicle (MPCV) Program within the National Aeronautics and Space Administration (NASA) Exploration Systems Mission Directorate. Crew and Thermal Systems Division performed this test in the eleven-foot human-rated vacuum chamber at the NASA Johnson Space Center. This testing is the first phase of suit loop testing to demonstrate the viability of the Environmental Control and Life Support System (ECLSS) being developed for Orion. APIST is the first in a series, which will consist of testing development hardware including the Carbon dioxide and Moisture Removal Amine Swing-bed (CAMRAS) and the air revitalization loop fan with human test subjects in pressure suits at varying suit pressures. Follow-on testing, to be conducted in 2013, will utilize the CAMRAS and a development regulator with human test subjects in pressure suits at varying cabin and suit pressures. This paper will discuss the results and findings of APIST and will also discuss future testing.

Bar-spheroid interaction in galaxies

NASA Technical Reports Server (NTRS)

Hernquist, Lars; Weinberg, Martin D.

1992-01-01

N-body simulation and linear analysis is employed to investigate the secular evolution of barred galaxies, with emphasis on the interaction between bars and spheroidal components of galaxies. This interaction is argued to drive secular transfer of angular momentum from bars to spheroids, primarily through resonant coupling. A moderately strong bar, having mass within corotation about 0.3 times the enclosed spheroid mass, is predicted to shed all its angular momentum typically in less than about 10 exp 9 yr. Even shorter depletion time scales are found for relatively more massive bars. It is suggested either that spheroids around barred galaxies are structured so as to inhibit strong coupling with bars, or that bars can form by unknown processes long after disks are established. The present models reinforce the notion that bars can drive secular evolution in galaxies.

49 CFR 178.345-13 - Pressure and leakage tests.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 49 Transportation 2 2010-10-01 2010-10-01 false Pressure and leakage tests. 178.345-13 Section 178... PACKAGINGS Specifications for Containers for Motor Vehicle Transportation § 178.345-13 Pressure and leakage tests. (a) Each cargo tank must be pressure and leakage tested in accordance with this section and...

Effect of a viscous fiber bar on postprandial glycemia in subjects with type 2 diabetes.

PubMed

Flammang, Ann M; Kendall, David M; Baumgartner, C John; Slagle, Trish D; Choe, Yong S

2006-10-01

To compare the effect of an experimental viscous fiber (VF) crispy bar on the postprandial glucose, insulin, and C-peptide response in adult subjects with type 2 diabetes to two commercially available control crispy bars. The study was a randomized, double-blinded, three period, crossover study. The study was conducted at two sites: Park Nicollet Institute, International Diabetes Center, Minneapolis, MN, and Radiant Research, Inc., Minneapolis, MN. A total of 60 adults with type 2 diabetes taking oral antihyperglycemic medication participated in the study. After an overnight fast, subjects consumed a test meal containing an equicaloric amount (300 kcal) of an experimental VF crispy bar or one of two commercially available crispy bars at each of three test visits, followed by a four hour meal tolerance test. Subjects also completed gastrointestinal (GI) response records for the 24 hours following each test visit. The VF crispy bars produced significantly lower glucose (p < 0.0001), insulin (p < 0.0001), and C-peptide (p < 0.0001) responses (as measured by positive area under the curve) in subjects with type 2 diabetes, as compared with the two commercially available bars. Intensity (p < 0.05) and frequency (p < 0.05) of flatulence were significantly higher with the VF bar as compared with the 2 commercial bars. While the VF bar produced significant subjective GI tolerance scoring values, the mean value was below 3 on a scale of 0 (no effect) to 10 (most severe effect) for all tested materials. The incorporation of VF into a crispy bar provided a means to improve blood glucose levels by reducing postprandial glucose, insulin, and C-peptide responses in subjects with type 2 diabetes. Though associated with some GI symptoms, VF may have application in improving the postprandial glycemic response in people with diabetes attempting intensive glucose control.

Spiroperidol, but not eticlopride or aripiprazole, produces gradual increases in descent latencies in the bar test in rats.

PubMed

Rocca, Jeffery F; Lister, Joshua G; Beninger, Richard J

2017-02-01

Rats repeatedly exposed to the bar test following injections with a dopamine D2-like receptor antagonist such as haloperidol show increased descent latencies, suggesting that contextual stimuli may lose their ability to elicit approach and other responses. Here, we showed that rats took progressively longer to initiate descent from a horizontal bar across sessions following daily intraperitoneal treatment (paired group) with the D2-like receptor antagonist, spiroperidol (0.125 and 0.25 mg/kg), but not in the control group that received 0.25 mg/kg in their home cage and testing following saline. When both groups were tested following an injection of spiroperidol or following saline, a sensitized and a conditioned increase in descent latency, respectively, were observed in the paired but not in the unpaired group. No evidence of sensitization or conditioning was found with the substituted benzamide compound, eticlopride (0.15-0.5 mg/kg), or the D2-like receptor partial agonist, aripiprazole (0.25-0.5 mg/kg). The different effects of these agents on learning may be related to different region-specific affinities for dopamine receptors or differences in receptor dissociation profiles. We suggest that the behavioural changes observed in spiroperidol-treated rats may reflect inverse incentive learning.

Characterization and modeling of mechanical behavior of single crystal titanium deformed by split-Hopkinson pressure bar

DOE PAGES

Morrow, B. M.; Lebensohn, R. A.; Trujillo, C. P.; ...

2016-03-28

Single crystal titanium samples were dynamically loaded using split-Hopkinson pressure bar (SHPB) and the resulting microstructures were examined. Characterization of the twins and dislocations present in the microstructure was conducted to understand the pathway for observed mechanical behavior. Electron backscatter diffraction (EBSD) was used to measure textures and quantify twinning. Microstructures were profusely twinned after loading, and twin variants and corresponding textures were different as a function of initial orientation. Focused ion beam (FIB) foils were created to analyze dislocation content using transmission electron microscopy (TEM). Large amounts of dislocations were present, indicating that plasticity was achieved through slip andmore » twinning together. Viscoplastic self-consistent (VPSC) modeling was used to confirm the complex order of operations during deformation. The activation of different mechanisms was highly dependent upon crystal orientation. For [0001] and View the MathML source[101¯1]-oriented crystals, compressive twinning was observed, followed by secondary tensile twinning. Furthermore, dislocations though prevalent in the microstructure, contributed to final texture far less than twinning.« less

49 CFR 178.347-5 - Pressure and leakage test.

Code of Federal Regulations, 2010 CFR

2010-10-01

... PACKAGINGS Specifications for Containers for Motor Vehicle Transportation § 178.347-5 Pressure and leakage test. (a) Each cargo tank must be tested in accordance with § 178.345-13 and this section. (b) Pressure..., the test pressure must be 40 psig or 1.5 times tank MAWP, whichever is greater, and the inspection...

Injection characteristics study of high-pressure direct injector for Compressed Natural Gas (CNG) using experimental and analytical method

NASA Astrophysics Data System (ADS)

Taha, Z.; Rahim, MF Abdul; Mamat, R.

2017-10-01

The injection characteristics of direct injector affect the mixture formation and combustion processes. In addition, the injector is converted from gasoline operation for CNG application. Thus measurement of CNG direct injector mass flow rate was done by independently tested a single injector on a test bench. The first case investigated the effect of CNG injection pressure and the second case evaluate the effect of pulse-width of injection duration. An analytical model was also developed to predict the mass flow rate of the injector. The injector was operated in a choked condition in both the experiments and simulation studies. In case 1, it was shown that mass flow rate through the injector is affected by injection pressure linearly. Based on the tested injection pressure of 20 bar to 60 bar, the resultant mass flow rate are in the range of 0.4 g/s to 1.2 g/s which are met with theoretical flow rate required by the engine. However, in Case 2, it was demonstrated that the average mass flow rate at short injection durations is lower than recorded in Case 1. At injection pressure of 50 bar, the average mass flow rate for Case 2 and Case 1 are 0.7 g/s and 1.1 g/s respectively. Also, the measured mass flow rate at short injection duration showing a fluctuating data in the range of 0.2 g/s - 1.3 g/s without any noticeable trends. The injector model able to predict the trend of the mass flow rate at different injection pressure but unable to track the fluctuating trend at short injection duration.

The paradox of extreme high-altitude migration in bar-headed geese Anser indicus

PubMed Central

Hawkes, L. A.; Balachandran, S.; Batbayar, N.; Butler, P. J.; Chua, B.; Douglas, D. C.; Frappell, P. B.; Hou, Y.; Milsom, W. K.; Newman, S. H.; Prosser, D. J.; Sathiyaselvam, P.; Scott, G. R.; Takekawa, J. Y.; Natsagdorj, T.; Wikelski, M.; Witt, M. J.; Yan, B.; Bishop, C. M.

2013-01-01

Bar-headed geese are renowned for migratory flights at extremely high altitudes over the world's tallest mountains, the Himalayas, where partial pressure of oxygen is dramatically reduced while flight costs, in terms of rate of oxygen consumption, are greatly increased. Such a mismatch is paradoxical, and it is not clear why geese might fly higher than is absolutely necessary. In addition, direct empirical measurements of high-altitude flight are lacking. We test whether migrating bar-headed geese actually minimize flight altitude and make use of favourable winds to reduce flight costs. By tracking 91 geese, we show that these birds typically travel through the valleys of the Himalayas and not over the summits. We report maximum flight altitudes of 7290 m and 6540 m for southbound and northbound geese, respectively, but with 95 per cent of locations received from less than 5489 m. Geese travelled along a route that was 112 km longer than the great circle (shortest distance) route, with transit ground speeds suggesting that they rarely profited from tailwinds. Bar-headed geese from these eastern populations generally travel only as high as the terrain beneath them dictates and rarely in profitable winds. Nevertheless, their migration represents an enormous challenge in conditions where humans and other mammals are only able to operate at levels well below their sea-level maxima. PMID:23118436

The paradox of extreme high-altitude migration in bar-headed geese Anser indicus

USGS Publications Warehouse

Hawkes, L.A.; Balachandran, S.; Batbayar, N.; Butler, P.J.; Chua, B.; Douglas, David C.; Frappell, P.B.; Hou, Y.; Milsom, W.K.; Newman, S.H.; Prosser, D.J.; Sathiyaselvam, P.; Scott, G.R.; Takekawa, John Y.; Natsagdorj, T.; Wikelski, M.; Witt, M.J.; Yan, B.; Bishop, C.M.

2012-01-01

Bar-headed geese are renowned for migratory flights at extremely high altitudes over the world's tallest mountains, the Himalayas, where partial pressure of oxygen is dramatically reduced while flight costs, in terms of rate of oxygen consumption, are greatly increased. Such a mismatch is paradoxical, and it is not clear why geese might fly higher than is absolutely necessary. In addition, direct empirical measurements of high-altitude flight are lacking. We test whether migrating bar-headed geese actually minimize flight altitude and make use of favourable winds to reduce flight costs. By tracking 91 geese, we show that these birds typically travel through the valleys of the Himalayas and not over the summits. We report maximum flight altitudes of 7290 m and 6540 m for southbound and northbound geese, respectively, but with 95 per cent of locations received from less than 5489 m. Geese travelled along a route that was 112 km longer than the great circle (shortest distance) route, with transit ground speeds suggesting that they rarely profited from tailwinds. Bar-headed geese from these eastern populations generally travel only as high as the terrain beneath them dictates and rarely in profitable winds. Nevertheless, their migration represents an enormous challenge in conditions where humans and other mammals are only able to operate at levels well below their sea-level maxima.

High-pressure cryogenic seals for pressure vessels

NASA Technical Reports Server (NTRS)

Buggele, A. E.

1977-01-01

This investigation of the problems associated with reliably containing gaseous helium pressurized to 1530 bars (22 500 psi) between 4.2 K and 150 K led to the following conclusions: (1) common seal designs used in existing elevated-temperature pressure vessels are unsuitable for high-pressure cryogenic operation, (2) extrusion seal-ring materials such as Teflon, tin, and lead are not good seal materials for cryogenic high-pressure operation; and (3) several high-pressure cryogenic seal systems suitable for large-pressure vessel applications were developed; two seals required prepressurization, and one seal functioned repeatedly without any prepressurization. These designs used indium seal rings, brass or 304 stainless-steel anvil rings, and two O-rings of silicone rubber or Kel-F.

Pressure Testing of a Minimum Gauge PRSEUS Panel

NASA Technical Reports Server (NTRS)

Lovejoy, Andrew J.; Rouse, Marshall; Linton, Kim A.; Li, Victor P.

2011-01-01

Advanced aircraft configurations that have been developed to increase fuel efficiency require advanced, novel structural concepts capable of handling the unique load conditions that arise. One such concept is the Pultruded Rod Stitched Efficient Unitized Structure (PRSEUS) developed by the Boeing Company. The PRSEUS concept is being investigated by NASA s Environmentally Responsible Aviation (ERA) Program for use in a hybrid-wing body (HWB) aircraft. This paper summarizes the analysis and test of a PRSEUS panel subjected to internal pressure, the first such pressure test for this structural concept. The pressure panel used minimum gauge skin, with stringer and frame configurations consistent with previous PRSEUS tests. Analysis indicated that for the minimum gauge skin panel, the stringer locations exhibit fairly linear response, but the skin bays between the stringers exhibit nonlinear response. Excellent agreement was seen between nonlinear analysis and test results in the critical portion at the center of the panel. The pristine panel was capable of withstanding the required 18.4 psi pressure load condition without exhibiting any damage. The impacted panel was capable of withstanding a pressure load in excess of 28 psi before initial failure occurred at the center stringer, and the panel was capable of sustaining increased pressure load after the initial failure. This successful PRSEUS panel pressure panel test was a critical step in the building block approach for enabling the use of this advanced structural concept on future aircraft, such as the HWB.

49 CFR 178.346-5 - Pressure and leakage tests.

Code of Federal Regulations, 2010 CFR

2010-10-01

... test pressure must be the greater of 5.0 psig or 1.5 times the cargo tank MAWP, and the inspection... PACKAGINGS Specifications for Containers for Motor Vehicle Transportation § 178.346-5 Pressure and leakage tests. (a) Each cargo tank must be tested in accordance with § 178.345-13 and this section. (b) Pressure...

Pressure Venting Tests of Phenolic Impregnated Carbon Ablator (PICA)

NASA Technical Reports Server (NTRS)

Blosser, Max L.; Knutson, Jeffrey R.

2015-01-01

A series of tests was devised to investigate the pressure venting behavior of one of the candidate ablators for the Orion capsule heat shield. Three different specimens of phenolic impregnated carbon ablator (PICA) were instrumented with internal pressure taps and subjected to rapid pressure changes from near vacuum to one atmosphere and simulated Orion ascent pressure histories. The specimens vented rapidly to ambient pressure and sustained no detectable damage during testing. Peak pressure differences through the thickness of a 3-inch-thick specimen were less than 1 psi during a simulated ascent pressure history.

The Pieper-Zulkowski pressure ulcer knowledge test.

PubMed

Pieper, Barbara; Zulkowski, Karen

2014-09-01

To describe the development and initial testing of the Pieper-Zulkowski Pressure Ulcer Knowledge Test (PZ-PUKT). Cross-sectional, instrument testing. Hospital association pressure ulcer educational program conference. Pressure ulcer research and guidelines from the last 5 years were examined for test item content. The initial PZ-PUKT had 115 items; response options were "true," "false," and "don't know." Registered nurses (N = 108) were randomly divided into 2 groups to take either the 60 prevention/risk and staging items or the 55 wound description items. Analyses of these responses resulted in 72 items, which were administered in total to a second cohort of 98 nurses for reliability. Cronbach's α was .80 for the 72-item PZ-PUKT. Cronbach's α values for the subscales were as follows: staging, .67; wound description, .64; and prevention/risk, .56. The mean correct scores were as follows: total, 80%; prevention, 77%; staging, 86%; and wound description, 77%. Nurses with wound care certification scored significantly higher on the PZ-PUKT than did nurses with other clinical certifications or with nurses who lacked certification. The PZ-PUKT has updated content about pressure ulcer prevention/risk, staging, and wound description. Reliability values are highest for the total test. Further use of the instrument in diverse settings will add to reliability testing and may provide direction for determination of a passing cutoff score.

Evaluation of spatial and functional roughness parameters on air-abraded zirconia as a function of particle type and deposition pressure.

PubMed

Queiroz, José Renato Cavalcanti; Botelho, Marco Antonio; Sousa, Samira Albuquerque de; Martinelli, Antonio Eduardo; Özcan, Mutlu

2015-02-01

This study evaluated the spatial and functional roughness parameters on air-abraded zirconia as a function of particle type and deposition pressure. Polished zirconia blocks (Cercon, Degussa/Dentsply) (N=30) with dimensions of 5 × 4 × 4 mm3 were air abraded according to 2 factors: a) particle type - 30-μm silica-coated alumina (CoJet) or alumina particles (45 μm); b) deposition pressure (1.5, 2.5 and 4.5 bar). Roughness parameters (Sdr, Vi, Sci and Svi) were measured in an optical profilometer (Wyko NT 1100) at the center of the air-abraded area (301.3 × 229.2 μm). Two measurements were made for each parameter from each surface. The means of each group were analyzed by 2-way ANOVA followed by Tukey's adjustment test and Student's t-test (alpha = 0.05). Both the particle type (p < 0.05) and deposition pressure (p < 0.05) significantly affected the roughness parameters. Interaction terms were significant except for Sci and Svi. With the increase in pressure from 1.5 to 4.5 bar, Sdr (CoJet 1.5: 15.7 ± 0.2; CoJet 4.5: 26.6 ± 0.2; alumina 1.5: 14.7 ± 0.2; alumina 4.5: 24.4 ± 0.2) and Vi (CoJet 1.5: 0.66 ± 0.01; CoJet 4.5: 1.37 ± 0.07; alumina 1.5: 0.62 ± 0.02; alumina 4.5: 1.19 ± 0.02) parameters showed a significant increase with both alumina and CoJet particles. Mean Sci values (CoJet 1.5: 1.62 ± 0.01, CoJet 4.5: 1.49 ± 0.02; alumina 1.5: 1.6 ± 0.03; alumina 4.5: 1.42 ± 0.04) and SVi (CoJet 1.5: 0.98 ± 0.01, CoJet 4.5: 0.112 ± 0.01; alumina 1.5: 0.98 ± 0.01, alumina 4.5: 0.12 ± 0.01) decreased significantly (p < 0.05) with the increase in pressure from 1.5 to 4.5 bar. The pressure increase from 2.5 to 4.5 bar did not cause any significant difference (p > 0.05) in these parameters for either particle type. Considering roughness parameters for micromechanical retention and parameters for adsorption mechanisms of adhesion, zirconia surfaces presented better morphological features when air abraded with silica-coated alumina than alumina particles at

Pressure probe study of the water relations of Phycomyces blakesleeanus sporangiophores

NASA Technical Reports Server (NTRS)

Cosgrove, D. J.; Ortega, J. K.; Shropshire, W. Jr

1987-01-01

The physical characteristics which govern the water relations of the giant-celled sporangiophore of Phycomyces blakesleeanus were measured with the pressure probe technique and with nanoliter osmometry. These properties are important because they govern water uptake associated with cell growth and because they may influence expansion of the sporangiophore wall. Turgor pressure ranged from 1.1 to 6.6 bars (mean = 4.1 bars), and was the same for stage I and stage IV sporangiophores. Sporangiophore osmotic pressure averaged 11.5 bars. From the difference between cell osmotic pressure and turgor pressure, the average water potential of the sporangiophore was calculated to be about -7.4 bars. When sporangiophores were submerged under water, turgor remained nearly constant. We propose that the low cell turgor pressure is due to solutes in the cell wall solution, i.e., between the cuticle and the plasma membrane. Membrane hydraulic conductivity averaged 4.6 x 10(-6) cm s-1 bar-1, and was significantly greater in stage I sporangiophores than in stage IV sporangiophores. Contrary to previous reports, the sporangiophore is separated from the supporting mycelium by septa which prevent bulk volume flow between the two regions. The presence of a wall compartment between the cuticle and the plasma membrane results in anomalous osmosis during pressure clamp measurements. This behavior arises because of changes in solute concentration as water moves into or out of the wall compartment surrounding the sporangiophore. Theoretical analysis shows how the equations governing transient water flow are altered by the characteristics of the cell wall compartment.

Laboratory and workplace assessments of rivet bucking bar vibration emissions.

PubMed

McDowell, Thomas W; Warren, Christopher; Xu, Xueyan S; Welcome, Daniel E; Dong, Ren G

2015-04-01

Sheet metal workers operating rivet bucking bars are at risk of developing hand and wrist musculoskeletal disorders associated with exposures to hand-transmitted vibrations and forceful exertions required to operate these hand tools. New bucking bar technologies have been introduced in efforts to reduce workplace vibration exposures to these workers. However, the efficacy of these new bucking bar designs has not been well documented. While there are standardized laboratory-based methodologies for assessing the vibration emissions of many types of powered hand tools, no such standard exists for rivet bucking bars. Therefore, this study included the development of a laboratory-based method for assessing bucking bar vibrations which utilizes a simulated riveting task. With this method, this study evaluated three traditional steel bucking bars, three similarly shaped tungsten alloy bars, and three bars featuring spring-dampeners. For comparison the bucking bar vibrations were also assessed during three typical riveting tasks at a large aircraft maintenance facility. The bucking bars were rank-ordered in terms of unweighted and frequency-weighted acceleration measured at the hand-tool interface. The results suggest that the developed laboratory method is a reasonable technique for ranking bucking bar vibration emissions; the lab-based riveting simulations produced similar rankings to the workplace rankings. However, the laboratory-based acceleration averages were considerably lower than the workplace measurements. These observations suggest that the laboratory test results are acceptable for comparing and screening bucking bars, but the laboratory measurements should not be directly used for assessing the risk of workplace bucking bar vibration exposures. The newer bucking bar technologies exhibited significantly reduced vibrations compared to the traditional steel bars. The results of this study, together with other information such as rivet quality, productivity, tool

Barring intervention? Lesbian and gay bars as an underutilized venue for tobacco interventions.

PubMed

Leibel, Katherine; Lee, Joseph G L; Goldstein, Adam O; Ranney, Leah M

2011-07-01

Lesbian, gay, bisexual, and transgender (LGBT) communities are at high risk for tobacco use. While LGBT communities have historically considered bars to be safe places to socialize and congregate, these spaces are often tobacco-friendly environments and may have potential as sites for much needed intervention. Only a few public health interventions have attempted to work through bars and clubs to decrease tobacco use in the LGBT populations. Evidence from HIV prevention suggests some potential interventions in bars, and the tobacco industry has worked extensively (and successfully) to utilize bars in marketing efforts. Lesbian and gay bars are underutilized in tobacco control, suggesting missed avenues for chronic disease prevention programs. Researchers and communities should continue to recognize the importance of clean indoor air laws covering bars and develop additional strategies for reaching LGBT populations with disparities.

Dowel bar retrofit performance in Wisconsin.

DOT National Transportation Integrated Search

2010-05-01

In 1999, WisDOT constructed test sections on I-39 to evaluate the dowel bar retrofit (DBR) rehabilitation technique for faulted concrete pavement slabs. Two years later, mortar deterioration and debonding were noted in the dowel slots. In response to...

Biomechanical and Cost Comparisons of Near-Far and Pin-Bar Constructs.

PubMed

Whitney Kluk, Augusta; Zhang, Tina; Russell, Joseph P; Kim, Hyunchul; Hsieh, Adam H; O'Toole, Robert V

2017-03-01

Orthopedic dogma states that external fixator stiffness is improved by placing 1 pin close to the fracture and 1 as distant as possible ("near-far"). This fixator construct is thought to be less expensive than placing pins a shorter distance apart and using "pin-bar" clamps that attach pins to outriggers. The authors therefore hypothesized that the near-far construct is stiffer and less expensive. They compared mechanical stiffness and costs of near-far and pin-bar constructs commonly used for temporary external fixation of femoral shaft fractures. Their testing model simulated femoral shaft fractures in damage control situations. Fourth-generation synthetic femora (n=18) were used. The near-far construct had 2 pins that were 106 mm apart, placed 25 mm from the gap on each side of the fracture. The pin-bar construct pins were 55 mm apart, placed 40 mm from the gap. Mechanical testing was performed on a material test system machine. Stiffness was determined in the linear portion of the load-displacement curve for both constructs in 4 modes: axial compression, torsional loading, frontal plane 3-point bending, and sagittal plane 3-point bending. Costs were determined from a 2012 price guide. Compared with the near-far construct, the pin-bar construct had stiffness increased by 58% in axial compression (P<.05) and by 52% in torsional loading (P<.05). The pin-bar construct increased cost by 11%. In contrast to the authors' hypothesis and existing orthopedic dogma, the near-far construct was less stiff than the pin-bar construct and was similarly priced. Use of the pin-bar construct is mechanically and economically reasonable. [Orthopedics. 2017; 40(2):e238-e241.]. Copyright 2016, SLACK Incorporated.

Tests Of Array Of Flush Pressure Sensors

NASA Technical Reports Server (NTRS)

Larson, Larry J.; Moes, Timothy R.; Siemers, Paul M., III

1992-01-01

Report describes tests of array of pressure sensors connected to small orifices flush with surface of 1/7-scale model of F-14 airplane in wind tunnel. Part of effort to determine whether pressure parameters consisting of various sums, differences, and ratios of measured pressures used to compute accurately free-stream values of stagnation pressure, static pressure, angle of attack, angle of sideslip, and mach number. Such arrays of sensors and associated processing circuitry integrated into advanced aircraft as parts of flight-monitoring and -controlling systems.

Ultrasound-Guided Bar Edge Labeling in the Perioperative Assessment of Nuss Bar Removal.

PubMed

Incerti, Filippo; Bertocchini, Alessia; Ghionzoli, Marco; Messineo, Antonio

2017-12-01

Nuss bar removal after minimally invasive repair of pectus excavatum in patients where bar ends are not palpable, can be a challenging procedure for the surgeon; a blind dissection toward the bar edges may lead to intercostal vessels or deep intercostal muscle injuries. In this article, we describe a fast, repeatable, low-cost technique to detect bar edge and stabilizers. A perioperative scan is performed by means of a portable ultrasonograph a few minutes before the operation. The bar edge stabilizer is detected as a hyperechogenic image with a concentric crescent while the bar edge is detected as a hyperechogenic dashed line with net edges. The scan is performed, and the actual projection on the skin of the metal plaque bulk is then labeled on the patient's chest by an ink marker. We believe that this method may improve morbidity, operative time, and consequently, hospitalization length and costs.

Interference of Nonstandard Interactions with Standard Model in {B^0} \\to {π ^0}\\bar vv, B_c^ - \\to {D^ - }\\bar vv and \\bar B_s^0 \\to {K^0}\\bar vv Decays

NASA Astrophysics Data System (ADS)

Mahmood, Shakeel; Tahir, Farida; Mir, Azeem

2018-05-01

We study the contributions of nonstandard neutrino interactions (NSI) to the rare decays of pseudoscalar mesons involving neutrinos in the final state {B^0} \\to {π ^0}\\bar vv, B_c^ - \\to {D^ - }\\bar vv and \\bar B_s^0 \\to {\\bar K^0}\\bar vv, It is pointed that dominant contribution comes from the interference between standard model and nonstandard interaction We predict limits on NSIs free parameter ɛ uL ττ and compare them with experimental data. We further compare our results with perturbative QCD (pQCD) and QCD results for these reactions.

The company they keep: drinking group attitudes and male bar aggression.

PubMed

Dumas, Tara M; Graham, Kathryn; Wells, Samantha

2015-05-01

The purpose of this study was to assess (a) similarities in self-reported bar-aggression-related attitudes and behaviors among members of young male groups recruited on their way to bars and (b) group-level variables associated with individual members' self-reported likelihood of perpetrating physical bar aggression in the past year, controlling for individual attitudes. Young, male, natural drinking groups recruited on their way to a bar district Thursday, Friday, and Saturday nights (n = 167, 53 groups) completed an online survey that measured whether they had perpetrated physical aggression at a bar in the past year and constructs associated with bar aggression, including attitudes toward male bar aggression and frequency of heavy episodic drinking in the past year. Intraclass correlations and chi-square tests demonstrated significant within-group similarity on bar-aggression-related attitudes and behaviors (ps < .01). Hierarchical linear modeling revealed that group attitudes toward bar aggression were significantly associated with individuals' likelihood of perpetrating physical bar aggression, controlling for individual attitudes (p < .01); however, the link between group heavy episodic drinking and self-reported bar aggression was nonsignificant in the full model. This study suggests that the most important group influence on young men's bar aggression is the attitudes of other group members. These attitudes were associated with group members' likelihood of engaging in bar aggression over and above individuals' own attitudes. A better understanding of how group attitudes and behavior affect the behavior of individual group members is needed to inform aggression-prevention programming.

Apparatus for testing high pressure injector elements

NASA Technical Reports Server (NTRS)

Myers, William Neill (Inventor); Scott, Ewell M. (Inventor); Forbes, John C. (Inventor); Shadoan, Michael D. (Inventor)

1995-01-01

An apparatus for testing and evaluating the spray pattern of high pressure fuel injector elements for use in supplying fuel to combustion engines is presented. Prior art fuel injector elements were normally tested by use of low pressure apparatuses which did not provide a purge to prevent mist from obscuring the injector element or to prevent frosting of the view windows; could utilize only one fluid during each test; and had their viewing ports positioned one hundred eighty (180 deg) apart, thus preventing optimum use of laser diagnostics. The high pressure fluid injector test apparatus includes an upper hub, an upper weldment or housing, a first clamp and stud/nut assembly for securing the upper hub to the upper weldment, a standoff assembly within the upper weldment, a pair of window housings having view glasses within the upper weldment, an injector block assembly and purge plate within the upper weldment for holding an injector element to be tested and evaluated, a lower weldment or housing, a second clamp and stud/nut assembly for securing the lower weldment to the upper hub, a third clamp and stud/nut assembly for securing the lower hub to the lower weldment, mechanisms for introducing fluid under high pressure for testing an injector element, and mechanisms for purging the apparatus to prevent frosting of view glasses within the window housings and to permit unobstructed viewing of the injector element.

Apparatus for testing high pressure injector elements

NASA Technical Reports Server (NTRS)

Myers, William Neill (Inventor); Scott, Ewell M. (Inventor); Forbes, John C. (Inventor); Shadoan, Michael D. (Inventor)

1993-01-01

An apparatus for testing and evaluating the spray pattern of high pressure fuel injector elements for use in supplying fuel to combustion engines is presented. Prior art fuel injector elements were normally tested by use of low pressure apparatuses which did not provide a purge to prevent mist from obscuring the injector element or to prevent frosting of the view windows; could utilize only one fluid during each test; and had their viewing ports positioned one hundred eighty (180 deg) apart, thus preventing optimum use of laser diagnostics. The high pressure fluid injector test apparatus includes an upper hub, an upper weldment or housing, a first clamp and stud/nut assembly for securing the upper hub to the upper weldment, a standoff assembly within the upper weldment, a pair of window housings having view glasses within the upper weldment, an injector block assembly and purge plate within the upper weldment for holding an injector element to be tested and evaluated, a lower weldment or housing, a second clamp and stud/nut assembly for securing the lower weldment to the upper weldment, a lower hub, a third clamp and stud/nut assembly for securing the lower hub to the lower weldment, mechanisms for introducing fluid under high pressure for testing an injector element, and mechanisms for purging the apparatus to prevent frosting of view glasses within the window housings and to permit unobstructed viewing of the injector element.

Pressure vessel burst test program - Initial program paper

NASA Technical Reports Server (NTRS)

Cain, Maurice R.; Sharp, Douglas E.; Coleman, Michael D.; Webb, Bobby L.

1990-01-01

The current status of a pressure vessel burst test program, aimed at the study of the blast waves and fragmentation characteristics of ruptured gas-filled pressure vessels, is reported. The program includes a series of test plans, each involving multiple bursts with burst pressures ranging to 7500 psig. The discussion covers the identification of concerns and hazards, application of the data generated, and a brief review of the current methods for assessing vessel safety and burst parameters. Attention is also given to pretest activities, including completed vessel and facility/instrumentation preparation and results of completed preliminary burst tests.

Extending the limits of operating pressure of narrow-bore column liquid chromatography instrumentation.

PubMed

Pauw, Ruben De; Degreef, Bart; Ritchie, Harald; Eeltink, Sebastiaan; Desmet, Gert; Broeckhoven, Ken

2014-06-20

The increase of the operating pressure in Liquid Chromatography, has been one of the crucial steps toward faster and more efficient separations. In the present contribution, it was investigated if the pressure limits for narrow-bore columns (2.1mm ID) could be increased beyond those of commercially available (1300bar) instrumentation without performance loss. Whereas previous studies applying pressures higher than 2000bar were limited to the use of columns with a diameter smaller or equal to 1mm, it is a difficult feat to expand this to 2.1mm ID given that viscous-heating effects increase according to the fifth power of the column radius. A prototype LC set-up was realized, allowing to operate at pressures up to 2600bar (260MPa) for large separation volumes (>5mL). The performance of an in-house-built injector was compared at 800bar to commercially available injectors, yielding equal performance but twice the maximum pressure rating. The performance of (coupled) custom columns packed with fully porous and superficially porous particles were assessed at ultra-high-pressure conditions. Increasing the inlet pressure from 800 to 2400bar and scaling the column length proportionally (from 150mm to 450mm), resulted in the theoretically expected linear increase in plate count from 20,000 to 59,000. A maximum plate number of 81,000 was realized using a 600mm long (coupled) column at 2600bar. Viscous-heating effects were diminished by insulating coupled columns and applying an intermediate-cooling strategy in a forced-air oven. Copyright © 2014 Elsevier B.V. All rights reserved.

Numerical modeling of barred spiral galaxies

NASA Astrophysics Data System (ADS)

Moore, Elizabeth Mary

1992-08-01

A two-component, self-consistent computer code to model spiral galaxies was written and tested and a method of inducing and controlling bar formation is developed. This work presents a departure from former modeling work done at the University of Florida, which depended on the beam scheme, a hydrodynamical code with a number of limitations. In particular, only the gas component could be modeled, no self-gravitational forces were included, and the viscosity inherent to the code could not be controlled easily. These shortcomings are overcome in the new algorithm. Most importantly, an attempt has been made to keep the models self-consistent. No perturbing potentials are imposed or required to excite bar and spiral structure. The code can model both the stellar and the gaseous component of a spiral galaxy. The stellar component feels only gravitational forces, while the gas component feels both gravitational and viscous forces. In addition, a halo force can be imposed for the purpose of stabilizing the disk. The code is a hybrid grid/smooth particle code. The gravitational forces are calculated on a Cartesian grid using a Fast Fourier Transform, while the gas viscous forces are calculated in a smooth particle manner. A mechanism for creating warm, featureless, stable disks is developed by taking moments of the collision less Boltzmann equation. In order to induce and control bar and spiral arm formation, the stabilizing stellar velocity dispersions are reduced in the center of the disk, but maintained in the outer regions. A bar forms naturally in the interior and the rotation of this bar helps maintain spiral structure in the outer gas disk. Realistic-looking spiral features are maintained in the gas component for as long as the models are calculated. A wide variety of bar and spiral structure can be formed by varying the size of the unstable central region, the rate of 'turn on', of the heating and the halo mass. We would like to test the model results by comparing

30 CFR 35.21 - Temperature-pressure spray-ignition tests.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Temperature-pressure spray-ignition tests. 35..., EVALUATION, AND APPROVAL OF MINING PRODUCTS FIRE-RESISTANT HYDRAULIC FLUIDS Test Requirements § 35.21 Temperature-pressure spray-ignition tests. (a) Purpose. The purpose of this test shall be to determine the...

30 CFR 35.21 - Temperature-pressure spray-ignition tests.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Temperature-pressure spray-ignition tests. 35..., EVALUATION, AND APPROVAL OF MINING PRODUCTS FIRE-RESISTANT HYDRAULIC FLUIDS Test Requirements § 35.21 Temperature-pressure spray-ignition tests. (a) Purpose. The purpose of this test shall be to determine the...

30 CFR 35.21 - Temperature-pressure spray-ignition tests.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Temperature-pressure spray-ignition tests. 35..., EVALUATION, AND APPROVAL OF MINING PRODUCTS FIRE-RESISTANT HYDRAULIC FLUIDS Test Requirements § 35.21 Temperature-pressure spray-ignition tests. (a) Purpose. The purpose of this test shall be to determine the...

30 CFR 35.21 - Temperature-pressure spray-ignition tests.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Temperature-pressure spray-ignition tests. 35..., EVALUATION, AND APPROVAL OF MINING PRODUCTS FIRE-RESISTANT HYDRAULIC FLUIDS Test Requirements § 35.21 Temperature-pressure spray-ignition tests. (a) Purpose. The purpose of this test shall be to determine the...

Centaur space vehicle pressurized propellant feed system tests

NASA Technical Reports Server (NTRS)

1972-01-01

Engine firing tests, using a full-scale flight-weight vehicle, were performed to evaluate a pressurized propellant feed system for the Centaur. The pressurant gases used were helium and hydrogen. The system was designed to replace the boost pumps currently used on Centaur. Two liquid oxygen tank pressurization modes were studied: (1) directly into the ullage and (2) below the propellant surface. Test results showed the two Centaur RL10 engines could be started and run over the range of expected flight variables. No system instabilities were encountered. Measured pressurization gas quantities agreed well with analytically predicted values.

Coffee straw can replace Hader bar for bar retained overdentures--a clinical report.

PubMed

Guttal, S S; Shetty, U S

2012-12-01

Bar attachment system provides retention and support for the overdenture. Retention of a mandibular denture can be achieved by an implant-retained or natural tooth-retained bar and stud attachment in the anterior segment of the mandible. A simple and cost effective treatment for more complex implant overdenture is the concept of conventional tooth-retained overdentures. The authors present a clinical report of a patient treated with a mandibular tooth-borne overdenture with a bar. The bar was fabricated using a coffee straw.

Partial entrainment of gravel bars during floods

USGS Publications Warehouse

Konrad, Christopher P.; Booth, Derek B.; Burges, Stephen J.; Montgomery, David R.

2002-01-01

Spatial patterns of bed material entrainment by floods were documented at seven gravel bars using arrays of metal washers (bed tags) placed in the streambed. The observed patterns were used to test a general stochastic model that bed material entrainment is a spatially independent, random process where the probability of entrainment is uniform over a gravel bar and a function of the peak dimensionless shear stress τ0* of the flood. The fraction of tags missing from a gravel bar during a flood, or partial entrainment, had an approximately normal distribution with respect to τ0* with a mean value (50% of the tags entrained) of 0.085 and standard deviation of 0.022 (root‐mean‐square error of 0.09). Variation in partial entrainment for a given τ0* demonstrated the effects of flow conditioning on bed strength, with lower values of partial entrainment after intermediate magnitude floods (0.065 < τ0*< 0.08) than after higher magnitude floods. Although the probability of bed material entrainment was approximately uniform over a gravel bar during individual floods and independent from flood to flood, regions of preferential stability and instability emerged at some bars over the course of a wet season. Deviations from spatially uniform and independent bed material entrainment were most pronounced for reaches with varied flow and in consecutive floods with small to intermediate magnitudes.

Influence of pressure on pyrolysis of black liquor: 1. Swelling.

PubMed

Whitty, Kevin; Backman, Rainer; Hupa, Mikko

2008-02-01

This is the first of two papers concerning the behavior of black liquor during pyrolysis under pressurized conditions. Two industrial kraft liquors were pyrolyzed in a laboratory-scale pressurized single particle reactor and a pressurized grid heater at temperatures ranging from 650 to 1100 degrees C and at pressures between 1 and 20 bar. The dimensions of the chars produced were measured and the specific swollen volume was calculated. Swelling decreased roughly logarithmically over the pressure range 1-20 r. An expression is developed to predict the specific swollen volume at elevated pressure when the volume at 1 bar is known. The bulk density of the char increased with pressure, indicating that liquors will be entrained less easily at higher pressures.

Apparatus and method for pressure testing closure disks

DOEpatents

Merten, Jr., Charles W.

1992-01-21

A method and device for testing the burst pressure of closure disks which provides high pressure to both sides of a disk and rapidly releases pressure from one side thereof causing a high rate of change of pressure. A hollow notched plug allows the rapid release of pressure upon rupturing. A tensile load is transmitted by a piston in combination with fluid pressure to the hollow notched plug.

Thermodynamic Properties of Nitrogen Including Liquid and Vapor Phases from 63K to 2000K with Pressures to 10,000 Bar

NASA Technical Reports Server (NTRS)

Jacobsen, Richard T.; Stewart, Richard B.

1973-01-01

Tables of thermodynamic properties of nitrogen are presented for the liquid and vapor phases for temperatures from the freezing line to 2000K and pressures to 10,000 bar. The tables include values of density, internal energy, enthalpy, entropy, isochoric heat capacity, isobaric heat capacity velocity of sound, the isotherm derivative, and the isochor derivative. The thermodynamic property tables are based on an equation of state, P=P (p,T), which accurately represents liquid and gaseous nitrogen for the range of pressures and temperatures covered by the tables. Comparisons of property values calculated from the equation of state with measured values for P-p-T, heat capacity, enthalpy, latent heat, and velocity of sound are included to illustrate the agreement between the experimental data and the tables of properties presented here. The coefficients of the equation of state were determined by a weighted least squares fit to selected P-p-T data and, simultaneously, to isochoric heat capacity data determined by corresponding states analysis from oxygen data, and to data which define the phase equilibrium criteria for the saturated liquid and the saturated vapor. The vapor pressure equation, melting curve equation, and an equation to represent the ideal gas heat capacity are also presented. Estimates of the accuracy of the equation of state, the vapor pressure equation, and the ideal gas heat capacity equation are given. The equation of state, derivatives of the equation, and the integral functions for calculating derived thermodynamic properties are included.

Effects of Gravel Bars on Nutrient Spiraling in Bedrock-Alluvium Streams

NASA Astrophysics Data System (ADS)

Iobst, B. R.; Carroll, E. P.; Furbish, D. J.

2007-05-01

The importance of the connection between nutrient transport and local stream geomorphology is becoming increasingly important. Studies have shown that the interconnectivity of nutrient cycles in the downstream direction is in part controlled by the distribution and size of gravel bars in low order streams, as hyporheic flow occurs dominantly through alternate and mid-channel gravel bars. For this investigation multiple gravel bars in a 3rd order bedrock-alluvium stream were studied to determine general relationships between nutrient spiraling and hyporheic flow. The first goal was to understand (1) the extent to which water moves through hyporheic zones and (2) the basic chemistry of the hyporheic water. The second part of the study was to understand how nutrients, notably nitrogen, are affected in their cycling by the relatively long residence times encountered in gravel bars during hyporheic flow. Wells were installed along a 600 m reach of Panther Creek, KY in selected bars, as well as in a secondary location involving a grid installation pattern in one large bar. Results have shown that hyporheic flow through gravel bars is an important factor in influencing stream chemistry. Background water chemistry surveys have shown that certain parameters, specifically ammonium and nitrogen concentrations vary downstream, and that the dominant control over these changes is gravel bar location. Rhodamine WT was used in field tracer tests to track the travel times of water through bars as well as partitioning of water between the open channel and hyporheic flows. Further tests will be conducted utilizing a stable isotope study to determine how nitrogen is affected by hyporheic flow, and what implications this has for nutrient transport. We expect results to show that the spacing and size of gravel bars is a dominant control in key nutrient spiraling parameters, namely uptake lengths and overall nitrogen cycling rates. This has implications for how natural systems will

Dynamic analysis of four bar planar mechanism extended to six-bar planar mechanism with variable topology

NASA Astrophysics Data System (ADS)

Belleri, Basayya K.; Kerur, Shravankumar B.

2018-04-01

A computer-oriented procedure for solving the dynamic force analysis problem for general planar mechanisms is presented. This paper provides position analysis, velocity analysis, acceleration analysis and force analysis of six bar mechanism with variable topology approach. Six bar mechanism is constructed by joining two simple four bar mechanisms. Initially the position, velocity and acceleration analysis of first four bar mechanism are determined by using the input parameters. The outputs (angular displacement, velocity and acceleration of rocker)of first four bar mechanism are used as input parameter for the second four bar mechanism and the position, velocity, acceleration and forces are analyzed. With out-put parameters of second four-bar mechanism the force analysis of first four-bar mechanism is carried out.

High-Pressure Oxygen Test Evaluations

NASA Technical Reports Server (NTRS)

Schwinghamer, R. J.; Key, C. F.

1974-01-01

The relevance of impact sensitivity testing to the development of the space shuttle main engine is discussed in the light of the special requirements for the engine. The background and history of the evolution of liquid and gaseous oxygen testing techniques and philosophy is discussed also. The parameters critical to reliable testing are treated in considerable detail, and test apparatus and procedures are described and discussed. Materials threshold sensitivity determination procedures are considered and a decision logic diagram for sensitivity threshold determination was plotted. Finally, high-pressure materials sensitivity test data are given for selected metallic and nonmetallic materials.

$${{\\bar{d}} - {\\bar{u}}}$$ Flavor Asymmetry in the Proton in Chiral Effective Field Theory

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

Salamu, Y.; Ji, Cheung-Ryong; Melnitchouk, Wally

2015-09-01

Themore » $${\\bar d - \\bar u}$$ flavor asymmetry in the proton arising from pion loops is computed using chiral effective field theory. calculation includes both nucleon and Δ intermediate states, and uses both the fully relativistic and heavy baryon frameworks. x dependence of $${\\bar d - \\bar u}$$ extracted from the Fermilab E866 Drell–Yan data can be well reproduced in terms of a single transverse momentum cutoff parameter regulating the ultraviolet behavior of the loop integrals. In addition to the distribution at x > 0, corrections to the integrated asymmetry from zero momentum contributions are computed, which arise from pion rainbow and bubble diagrams at x = 0. These have not been accounted for in previous analyses, and can make important contributions to the lowest moment of $${\\bar d-\\bar u}$$ .« less

Dynamic tensile characterization of a 4330 steel with kolsky bar techniques.

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

Song, Bo; Antoun, Bonnie R.; Connelly, Kevin

2010-08-01

There has been increasing demand to understand the stress-strain response as well as damage and failure mechanisms of materials under impact loading condition. Dynamic tensile characterization has been an efficient approach to acquire satisfactory information of mechanical properties including damage and failure of the materials under investigation. However, in order to obtain valid experimental data, reliable tensile experimental techniques at high strain rates are required. This includes not only precise experimental apparatus but also reliable experimental procedures and comprehensive data interpretation. Kolsky bar, originally developed by Kolsky in 1949 [1] for high-rate compressive characterization of materials, has been extended formore » dynamic tensile testing since 1960 [2]. In comparison to Kolsky compression bar, the experimental design of Kolsky tension bar has been much more diversified, particularly in producing high speed tensile pulses in the bars. Moreover, instead of directly sandwiching the cylindrical specimen between the bars in Kolsky bar compression bar experiments, the specimen must be firmly attached to the bar ends in Kolsky tensile bar experiments. A common method is to thread a dumbbell specimen into the ends of the incident and transmission bars. The relatively complicated striking and specimen gripping systems in Kolsky tension bar techniques often lead to disturbance in stress wave propagation in the bars, requiring appropriate interpretation of experimental data. In this study, we employed a modified Kolsky tension bar, newly developed at Sandia National Laboratories, Livermore, CA, to explore the dynamic tensile response of a 4330-V steel. The design of the new Kolsky tension bar has been presented at 2010 SEM Annual Conference [3]. Figures 1 and 2 show the actual photograph and schematic of the Kolsky tension bar, respectively. As shown in Fig. 2, the gun barrel is directly connected to the incident bar with a coupler. The

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

NASA Technical Reports Server (NTRS)

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

2008-01-01

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

49 CFR 178.348-5 - Pressure and leakage test.

Code of Federal Regulations, 2010 CFR

2010-10-01

... PACKAGINGS Specifications for Containers for Motor Vehicle Transportation § 178.348-5 Pressure and leakage test. (a) Each cargo tank must be tested in accordance with § 178.345-13 and this section. (b) Pressure....5 times tank MAWP, and the inspection pressure is tank MAWP. [Amdt. 178-89, 54 FR 25032, June 12...

Influence of pressure and temperature on molar volume and retention properties of peptides in ultra-high pressure liquid chromatography.

PubMed

Fekete, Szabolcs; Horváth, Krisztián; Guillarme, Davy

2013-10-11

In this study, pressure induced changes in retention were measured for model peptides possessing molecular weights between ∼1 and ∼4kDa. The goal of the present work was to evaluate if such changes were only attributed to the variation of molar volume and if they could be estimated prior to the experiments, using theoretical models. Restrictor tubing was employed to generate pressures up to 1000bar and experiments were conducted for mobile phase temperatures comprised between 30 and 80°C. As expected, the retention increases significantly with pressure, up to 200% for glucagon at around 1000bar compared to ∼100bar. The obtained data were fitted with a theoretical model and the determination coefficients were excellent (r(2)>0.9992) for the peptides at various temperatures. On the other hand, the pressure induced change in retention was found to be temperature dependent and was more pronounced at 30°C vs. 60 or 80°C. Finally, using the proposed model, it was possible to easily estimate the pressure induced increase in retention for any peptide and mobile phase temperature. This allows to easily estimating the expected change in retention, when increasing the column length under UHPLC conditions. Copyright © 2013 Elsevier B.V. All rights reserved.

33 CFR 159.111 - Pressure and vacuum pulse test.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Pressure and vacuum pulse test... (CONTINUED) POLLUTION MARINE SANITATION DEVICES Design, Construction, and Testing § 159.111 Pressure and vacuum pulse test. Liquid retention components of the device with manufacturer specified venting...

33 CFR 159.111 - Pressure and vacuum pulse test.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 33 Navigation and Navigable Waters 2 2012-07-01 2012-07-01 false Pressure and vacuum pulse test... (CONTINUED) POLLUTION MARINE SANITATION DEVICES Design, Construction, and Testing § 159.111 Pressure and vacuum pulse test. Liquid retention components of the device with manufacturer specified venting...

33 CFR 159.111 - Pressure and vacuum pulse test.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 33 Navigation and Navigable Waters 2 2014-07-01 2014-07-01 false Pressure and vacuum pulse test... (CONTINUED) POLLUTION MARINE SANITATION DEVICES Design, Construction, and Testing § 159.111 Pressure and vacuum pulse test. Liquid retention components of the device with manufacturer specified venting...

Liquid Oxygen Thermodynamic Vent System Testing with Helium Pressurization

NASA Technical Reports Server (NTRS)

VanDresar, Neil T.

2014-01-01

This report presents the results of several thermodynamic vent system (TVS) tests with liquid oxygen plus a test with liquid nitrogen. In all tests, the liquid was heated above its normal boiling point to 111 K for oxygen and 100 K for nitrogen. The elevated temperature was representative of tank conditions for a candidate lunar lander ascent stage. An initial test series was conducted with saturated oxygen liquid and vapor at 0.6 MPa. The initial series was followed by tests where the test tank was pressurized with gaseous helium to 1.4 to 1.6 MPa. For these tests, the helium mole fraction in the ullage was quite high, about 0.57 to 0.62. TVS behavior is different when helium is present than when helium is absent. The tank pressure becomes the sum of the vapor pressure and the partial pressure of helium. Therefore, tank pressure depends not only on temperature, as is the case for a pure liquid-vapor system, but also on helium density (i.e., the mass of helium divided by the ullage volume). Thus, properly controlling TVS operation is more challenging with helium pressurization than without helium pressurization. When helium was present, the liquid temperature would rise with each successive TVS cycle if tank pressure was kept within a constant control band. Alternatively, if the liquid temperature was maintained within a constant TVS control band, the tank pressure would drop with each TVS cycle. The final test series, which was conducted with liquid nitrogen pressurized with helium, demonstrated simultaneous pressure and temperature control during TVS operation. The simultaneous control was achieved by systematic injection of additional helium during each TVS cycle. Adding helium maintained the helium partial pressure as the liquid volume decreased because of TVS operation. The TVS demonstrations with liquid oxygen pressurized with helium were conducted with three different fluid-mixer configurations-a submerged axial jet mixer, a pair of spray hoops in the tank

Calculated shock pressures in the aquarium test

NASA Astrophysics Data System (ADS)

Johnson, J. N.

1982-04-01

A new method of analysis has been developed for determintion of shock pressures in aquarium tests on commercial explosives. This test consists of photographing the expanding cylindrical tube wall (which contains the detonation products) and the shock wave in water surrounding the explosive charge. By making a least-squares fit to the shock-front data, it is possible to determine the peak shock-front pressure as a function of distance from the cylinder wall. This has been done for 10-cm and 20-cm-diam ANFO (ammonium nitrate/fuel oil) and aluminized ANFO (7.5 wt% Al) aquarium test data.

High-pressure cryogenic valves for the Vulcain rocket motor

NASA Astrophysics Data System (ADS)

Garceau, P.; Meyer, F.

The high-pressure valve developed to control the flow of liquid oxygen or hydrogen into the gas generator of the ESA Vulcain rocket motor is described. The spherical ball-seal design employed provides high reliability over a service lifetime of 5000 on-off actuations at temperatures 20-350 K and pressures up to 200 bar. Leakage is limited to a few cu cm/sec of hydrogen at 20 K. The steps in the development process, from the definition of the valve specifications to the fabrication and testing phase are reviewed, and the final design is shown in drawings, diagrams, and photographs.

Comparative study of (0001) and (11\\bar{2}2) InGaN based light emitting diodes

NASA Astrophysics Data System (ADS)

Pristovsek, Markus; Humphreys, Colin J.; Bauer, Sebastian; Knab, Manuel; Thonke, Klaus; Kozlowski, Grzegorz; O'Mahony, Donagh; Maaskant, Pleun; Corbett, Brian

2016-05-01

We have systematically investigated the doping of (11\\bar{2}2) with Si and Mg by metal-organic vapour phase epitaxy for light emitting diodes (LEDs). By Si doping of GaN we reached electron concentrations close to 1020 cm-3, but the topography degrades above mid 1019 cm-3. By Mg doping we reached hole concentrations close to 5 × 1017 cm-3, using Mg partial pressures about 3× higher than those for (0001). Exceeding the maximum Mg partial pressure led to a quick degradation of the sample. Low resistivities as well as high hole concentrations required a growth temperature of 900 °C or higher. At optimised conditions the electrical properties as well as the photoluminescence of (11\\bar{2}2) p-GaN were similar to (0001) p-GaN. The best ohmic p-contacts were achieved by NiAg metallisation. A single quantum well LED emitting at 465 nm was realised on (0001) and (11\\bar{2}2). Droop (sub-linear increase of the light output power) occurred at much higher current densities on (11\\bar{2}2). However, the light output of the (0001) LED was higher than that of (11\\bar{2}2) until deep in the droop regime. Our LEDs as well as those in the literature indicate a reduction in efficiency from (0001) over semi-polar to non-polar orientations. We propose that reduced fields open a loss channel for carriers.

Measurement of the forward-backward asymmetry of $$\\Lambda$$ and $$\\bar{\\Lambda}$$ production in $$p \\bar{p}$$ collisions

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

Abazov, Victor Mukhamedovich

Here, we studymore » $$\\Lambda$$ and $$\\bar{\\Lambda}$$ production asymmetries in $$p \\bar{p} \\rightarrow \\Lambda (\\bar{\\Lambda}) X$$, $$p \\bar{p} \\rightarrow J/\\psi \\Lambda (\\bar{\\Lambda}) X$$, and $$p \\bar{p} \\rightarrow \\mu^\\pm \\Lambda (\\bar{\\Lambda}) X$$ events recorded by the D0 detector at the Fermilab Tevatron collider at $$\\sqrt{s} = 1.96$$ TeV. We find an excess of $$\\Lambda$$'s ($$\\bar{\\Lambda}$$'s) produced in the proton (antiproton) direction. This forward-backward asymmetry is measured as a function of rapidity. We confirm that the $$\\bar{\\Lambda}/\\Lambda$$ production ratio, measured by several experiments with various targets and a wide range of energies, is a universal function of "rapidity loss", i.e., the rapidity difference of the beam proton and the lambda.« less

Measurement of the forward-backward asymmetry of $$\\Lambda$$ and $$\\bar{\\Lambda}$$ production in $$p \\bar{p}$$ collisions

DOE PAGES

Abazov, Victor Mukhamedovich

2016-02-09

Here, we studymore » $$\\Lambda$$ and $$\\bar{\\Lambda}$$ production asymmetries in $$p \\bar{p} \\rightarrow \\Lambda (\\bar{\\Lambda}) X$$, $$p \\bar{p} \\rightarrow J/\\psi \\Lambda (\\bar{\\Lambda}) X$$, and $$p \\bar{p} \\rightarrow \\mu^\\pm \\Lambda (\\bar{\\Lambda}) X$$ events recorded by the D0 detector at the Fermilab Tevatron collider at $$\\sqrt{s} = 1.96$$ TeV. We find an excess of $$\\Lambda$$'s ($$\\bar{\\Lambda}$$'s) produced in the proton (antiproton) direction. This forward-backward asymmetry is measured as a function of rapidity. We confirm that the $$\\bar{\\Lambda}/\\Lambda$$ production ratio, measured by several experiments with various targets and a wide range of energies, is a universal function of "rapidity loss", i.e., the rapidity difference of the beam proton and the lambda.« less

Constant pressure high throughput membrane permeation testing system

DOEpatents

Albenze, Erik J.; Hopkinson, David P.; Luebke, David R.

2014-09-02

The disclosure relates to a membrane testing system for individual evaluation of a plurality of planar membranes subjected to a feed gas on one side and a sweep gas on a second side. The membrane testing system provides a pressurized flow of a feed and sweep gas to each membrane testing cell in a plurality of membrane testing cells while a stream of retentate gas from each membrane testing cell is ported by a retentate multiport valve for sampling or venting, and a stream of permeate gas from each membrane testing cell is ported by a permeate multiport valve for sampling or venting. Back pressure regulators and mass flow controllers act to maintain substantially equivalent gas pressures and flow rates on each side of the planar membrane throughout a sampling cycle. A digital controller may be utilized to position the retentate and permeate multiport valves cyclically, allowing for gas sampling of different membrane cells over an extended period of time.

An investigation of the tri-bar gripping system on isometric muscular endurance.

PubMed

Drury, Daniel G; Faggiono, Heath; Stuempfle, Kristin J

2004-11-01

Recently, a new product called the Tri-Bar has been introduced as an alternative to the standard round weightlifting bar. The Tri-Bar has the same weight, length, and circumference as a standard weightlifting bar and differs only in that the shape of the bar is formed like a triangle with rounded edges. Theoretically, the shape of the bar will enhance gripping comfort and increase muscular endurance. We studied 32 moderately trained males who were free from upper-body injury or limitation. Each participant completed 4 visits to the lab as part of 2 separate investigations. The first investigation was a comparison of straight-arm hang times while grasping a standard Olympic bar or a Tri-Bar attached to the top of a power rack. The second investigation involved grasping a standard revolving cable handle or a Tri-Bar revolving handle attached to a weight equal to half the subject's body weight. In both investigations, time was used as a measure of isometric muscular endurance. Differences were determined using a dependent t-test, and a level of significance was set at p < 0.05. Mean hang times were significantly longer when the men hung from the Tri-Bar (107.6 seconds) versus the standard bar (95.4 seconds) (p = 0.015). Conversely, in the investigation using the revolving handles, the round bar produced longer grasping times (71.5 seconds) than the Tri-Bar (62.6 seconds) (p = 0.000). The results of this investigation indicate that a fixed and stable Tri-Bar may help to increase hang time, but a Tri-Bar free to rotate within the grasp may decrease grasping time in comparison to a standard round handle. With regard to exercises that require isometric grasping, the Tri-Bar may be an effective alternative to the standard bar for increasing isometric grasping endurance.

What makes the family of barred disc galaxies so rich: damping stellar bars in spinning haloes

NASA Astrophysics Data System (ADS)

Collier, Angela; Shlosman, Isaac; Heller, Clayton

2018-05-01

We model and analyse the secular evolution of stellar bars in spinning dark matter (DM) haloes with the cosmological spin λ ˜ 0-0.09. Using high-resolution stellar and DM numerical simulations, we focus on angular momentum exchange between stellar discs and DM haloes of various axisymmetric shapes - spherical, oblate, and prolate. We find that stellar bars experience a diverse evolution that is guided by the ability of parent haloes to absorb angular momentum, J, lost by the disc through the action of gravitational torques, resonant and non-resonant. We confirm that dynamical bar instability is accelerated via resonant J-transfer to the halo. Our main findings relate to the long-term secular evolution of disc-halo systems: with an increasing λ, bars experience less growth and basically dissolve after they pass through vertical buckling instability. Specifically, with increasing λ, (1) the vertical buckling instability in stellar bars colludes with inability of the inner halo to absorb J - this emerges as the main factor weakening or destroying bars in spinning haloes; (2) bars lose progressively less J, and their pattern speeds level off; (3) bars are smaller, and for λ ≳ 0.06 cease their growth completely following buckling; (4) bars in λ > 0.03 haloes have ratio of corotation-to-bar radii, RCR/Rb > 2, and represent so-called slow bars without offset dust lanes. We provide a quantitative analysis of J-transfer in disc-halo systems, and explain the reasons for absence of growth in fast spinning haloes and its observational corollaries. We conclude that stellar bar evolution is substantially more complex than anticipated, and bars are not as resilient as has been considered so far.

Secular Evolution in Barred Galaxies: Observations

NASA Astrophysics Data System (ADS)

Merrifield, M.

2002-12-01

This paper describes a framework for studying galaxy morphology, particularly bar strength, in a quantitative manner, and presents applications of this approach that reveal observational evidence for secular evolution in bar morphology. The distribution of bar strength in galaxies is quite strongly bimodal, suggesting that barred and unbarred systems are distinct entities, and that any evolution between these two states must occur on a relatively rapid timescale. Bars' strengths appear to be correlated with their pattern speeds, implying that these structures weaken as they start to slow, and disappear entirely before the bars have slowed significantly. There is also tantalizing evidence that bars are rare beyond a redshift of z ~ 0.7, indicating that galaxies have only recently evolved to a point where bars can readily form.

49 CFR 179.500-16 - Tests of pressure relief devices.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 49 Transportation 3 2013-10-01 2013-10-01 false Tests of pressure relief devices. 179.500-16... CARS Specification for Cryogenic Liquid Tank Car Tanks and Seamless Steel Tanks (Classes DOT-113 and 107A) § 179.500-16 Tests of pressure relief devices. (a) Pressure relief valves shall be tested by air...

49 CFR 179.500-16 - Tests of pressure relief devices.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 49 Transportation 3 2011-10-01 2011-10-01 false Tests of pressure relief devices. 179.500-16... CARS Specification for Cryogenic Liquid Tank Car Tanks and Seamless Steel Tanks (Classes DOT-113 and 107A) § 179.500-16 Tests of pressure relief devices. (a) Pressure relief valves shall be tested by air...

49 CFR 179.500-16 - Tests of pressure relief devices.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 49 Transportation 3 2012-10-01 2012-10-01 false Tests of pressure relief devices. 179.500-16... CARS Specification for Cryogenic Liquid Tank Car Tanks and Seamless Steel Tanks (Classes DOT-113 and 107A) § 179.500-16 Tests of pressure relief devices. (a) Pressure relief valves shall be tested by air...

49 CFR 179.500-16 - Tests of pressure relief devices.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 49 Transportation 3 2014-10-01 2014-10-01 false Tests of pressure relief devices. 179.500-16... CARS Specification for Cryogenic Liquid Tank Car Tanks and Seamless Steel Tanks (Classes DOT-113 and 107A) § 179.500-16 Tests of pressure relief devices. (a) Pressure relief valves shall be tested by air...

Investigation of dowel bar placement accuracy with a dowel bar inserter

DOT National Transportation Integrated Search

2003-05-01

Dowel bar inserters (DBI) on concrete paving equipment eliminate the need for manually placing dowel bar baskets. Reduced manual labor eventually pays off the initial investment in a DBI and ultimately results in reduced PCCP costs to the roadway own...

Machine learning techniques in searches for$$t\\bar{t}$$h in the h → $$b\\bar{b}$$ decay channel

DOE PAGES

Santos, Robert; Nguyen, M.; Webster, Jordan; ...

2017-04-10

Study of the production of pairs of top quarks in association with a Higgs boson is one of the primary goals of the Large Hadron Collider over the next decade, as measurements of this process may help us to understand whether the uniquely large mass of the top quark plays a special role in electroweak symmetry breaking. Higgs bosons decay predominantly to bmore » $$\\bar{_b}$$, yielding signatures for the signal that are similar to t$$\\bar{_t}$$ + jets with heavy flavor. Though particularly challenging to study due to the similar kinematics between signal and background events, such final states (t$$\\bar{_t}$$b$$\\bar{b}$$) are an important channel for studying the top quark Yukawa coupling. This paper presents a systematic study of machine learning (ML) methods for detecting t$$\\bar{_t}$$h in the h → b$$\\bar{b}$$ decay channel. Among the seven ML methods tested, we show that neural network models outperform alternative methods. In addition, two neural models used in this paper outperform NeuroBayes, one of the standard algorithms used in current particle physics experiments. We further study the effectiveness of ML algorithms by investigating the impact of feature set and data size, as well as the depth of the networks for neural models. We demonstrate that an extended feature set leads to improvement of performance over basic features. Furthermore, the availability of large samples for training is found to be important for improving the performance of the techniques. For the features and the data set studied here, neural networks of more layers deliver comparable performance to their simpler counterparts.« less

Machine learning techniques in searches for$$t\\bar{t}$$h in the h → $$b\\bar{b}$$ decay channel

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

Santos, Robert; Nguyen, M.; Webster, Jordan

Study of the production of pairs of top quarks in association with a Higgs boson is one of the primary goals of the Large Hadron Collider over the next decade, as measurements of this process may help us to understand whether the uniquely large mass of the top quark plays a special role in electroweak symmetry breaking. Higgs bosons decay predominantly to bmore » $$\\bar{_b}$$, yielding signatures for the signal that are similar to t$$\\bar{_t}$$ + jets with heavy flavor. Though particularly challenging to study due to the similar kinematics between signal and background events, such final states (t$$\\bar{_t}$$b$$\\bar{b}$$) are an important channel for studying the top quark Yukawa coupling. This paper presents a systematic study of machine learning (ML) methods for detecting t$$\\bar{_t}$$h in the h → b$$\\bar{b}$$ decay channel. Among the seven ML methods tested, we show that neural network models outperform alternative methods. In addition, two neural models used in this paper outperform NeuroBayes, one of the standard algorithms used in current particle physics experiments. We further study the effectiveness of ML algorithms by investigating the impact of feature set and data size, as well as the depth of the networks for neural models. We demonstrate that an extended feature set leads to improvement of performance over basic features. Furthermore, the availability of large samples for training is found to be important for improving the performance of the techniques. For the features and the data set studied here, neural networks of more layers deliver comparable performance to their simpler counterparts.« less

Reduced Pressure Cabin Testing of the Orion Atmosphere Revitalization Technology

NASA Technical Reports Server (NTRS)

Button, Amy; Sweterlitsch, Jeffrey

2011-01-01

An amine-based carbon dioxide (CO2) and water vapor sorbent in pressure-swing regenerable beds has been developed by Hamilton Sundstrand and baselined for the Atmosphere Revitalization System for moderate duration missions of the Orion Multipurpose Crew Vehicle. In previous years at this conference, reports were presented on extensive Johnson Space Center testing of this technology in a sea-level pressure environment with simulated and actual human metabolic loads in both open and closed-loop configurations. In 2011, the technology was tested in an open cabin-loop configuration at ambient and two sub-ambient pressures to compare the performance of the system to the results of previous tests at ambient pressure. The testing used a human metabolic simulator with a different type of water vapor generation than previously used, which added some unique challenges in the data analysis. This paper summarizes the results of: baseline and some matrix testing at all three cabin pressures, increased vacuum regeneration line pressure with a high metabolic load, a set of tests studying CO2 and water vapor co-adsorption effects relative to model-predicted performance, and validation tests of flight program computer model predictions with specific operating conditions.

Reduced Pressure Cabin Testing of the Orion Atmosphere Revitalization Technology

NASA Technical Reports Server (NTRS)

Button, Amy; Sweterlisch, Jeffery J.

2013-01-01

An amine-based carbon dioxide (CO2) and water vapor sorbent in pressure-swing regenerable beds has been developed by Hamilton Sundstrand and baselined for the Atmosphere Revitalization System for moderate duration missions of the Orion Multipurpose Crew Vehicle. In previous years at this conference, reports were presented on extensive Johnson Space Center testing of this technology in a sea-level pressure environment with simulated and actual human metabolic loads in both open and closed-loop configurations. In 2011, the technology was tested in an open cabin-loop configuration at ambient and two sub-ambient pressures to compare the performance of the system to the results of previous tests at ambient pressure. The testing used a human metabolic simulator with a different type of water vapor generation than previously used, which added some unique challenges in the data analysis. This paper summarizes the results of: baseline and some matrix testing at all three cabin pressures, increased vacuum regeneration line pressure with a high metabolic load, a set of tests studying CO2 and water vapor co-adsorption effects relative to model-predicted performance, and validation tests of flight program computer model predictions with specific operating conditions.

Suppression of span in sealed microcavity Fabry-Perot pressure sensors

NASA Astrophysics Data System (ADS)

Mishra, Shivam; Rajappa, Balasubramaniam; Chandra, Sudhir

2017-01-01

Optical microelectromechanical system pressure sensors working on the principle of extrinsic Fabry-Perot (FP) interferometer are designed and fabricated for pressure range of 1-bar absolute. Anodic bonding of silicon with glass is performed under atmospheric pressure to form FP cavity. This process results in entrapment of gas in the sealed microcavity. The effect of trapped gas is investigated on sensor characteristics. A closed-loop solution is derived for the deflection of the diaphragm of a sealed microcavity pressure sensor. Phenomenon of "suppression of span" is brought out. The sensors are tested using white light interferometry technique. The residual pressure of the trapped gas is estimated from the experiments. The developed model has been used to estimate the deflection sensitivity of the free diaphragm and the extent of suppression of span after bonding.

High-power diode laser bars as pump sources for fiber lasers and amplifiers (Invited Paper)

NASA Astrophysics Data System (ADS)

Bonati, G.; Hennig, P.; Wolff, D.; Voelckel, H.; Gabler, T.; Krause, U.; T'nnermann, A.; Reich, M.; Limpert, J.; Werner, E.; Liem, A.

2005-04-01

Fiber lasers are pumped by fibercoupled, multimode single chip devices at 915nm. That"s what everybody assumes when asked for the type of fiber laser pumps and it was like this for many years. Coming up as an amplifier for telecom applications, the amount of pump power needed was in the range of several watts. Highest pump powers for a limited market entered the ten watts range. This is a range of power that can be covered by highly reliable multimode chips, that have to survive up to 25 years, e.g. in submarine applications. With fiber lasers entering the power range and the application fields of rod and thin disc lasers, the amount of pump power needed raised into the area of several hundred watts. In this area of pump power, usually bar based pumps are used. This is due to the much higher cost pressure of the industrial customers compared to telecom customers. We expect more then 70% of all industrial systems to be pumped by diode laser bars. Predictions that bar based pumps survive for just a thousand hours in cw-operation and fractions of this if pulsed are wrong. Bar based pumps have to perform on full power for 10.000h on Micro channel heat sinks and 20.000h on passive heatsinks in industrial applications, and they do. We will show a variety of data, "real" long time tests and statistics from the JENOPTIK Laserdiode as well as data of thousands of bars in the field, showing that bar based pumps are not just well suitable for industrial applications on high power levels, but even showing benefits compared to chip based pumps. And it"s reasonable, that the same objectives of cost effectiveness, power and lifetime apply as well to thin disc, rod and slab lasers as to fiber lasers. Due to the pumping of fiber lasers, examples will be shown, how to utilize bars for high brightness fiber coupling. In this area, the automation is on its way to reduce the costs on the fibercoupling, similar to what had been done in the single chip business. All these efforts are

Soft x-ray spectroscopy of high pressure liquid.

PubMed

Qiao, Ruimin; Xia, Yujian; Feng, Xuefei; Macdougall, James; Pepper, John; Armitage, Kevin; Borsos, Jason; Knauss, Kevin G; Lee, Namhey; Allézy, Arnaud; Gilbert, Benjamin; MacDowell, Alastair A; Liu, Yi-Sheng; Glans, Per-Anders; Sun, Xuhui; Chao, Weilun; Guo, Jinghua

2018-01-01

We describe a new experimental technique that allows for soft x-ray spectroscopy studies (∼100-1000 eV) of high pressure liquid (∼100 bars). We achieve this through a liquid cell with a 100 nm-thick Si 3 N 4 membrane window, which is sandwiched by two identical O-rings for vacuum sealing. The thin Si 3 N 4 membrane allows soft x-rays to penetrate, while separating the high-pressure liquid under investigation from the vacuum required for soft x-ray transmission and detection. The burst pressure of the Si 3 N 4 membrane increases with decreasing size and more specifically is inversely proportional to the side length of the square window. It also increases proportionally with the membrane thickness. Pressures > 60 bars could be achieved for 100 nm-thick square Si 3 N 4 windows that are smaller than 65 μm. However, above a certain pressure, the failure of the Si wafer becomes the limiting factor. The failure pressure of the Si wafer is sensitive to the wafer thickness. Moreover, the deformation of the Si 3 N 4 membrane is quantified using vertical scanning interferometry. As an example of the performance of the high-pressure liquid cell optimized for total-fluorescence detected soft x-ray absorption spectroscopy (sXAS), the sXAS spectra at the Ca L edge (∼350 eV) of a CaCl 2 aqueous solution are collected under different pressures up to 41 bars.

Soft x-ray spectroscopy of high pressure liquid

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

Qiao, Ruimin; Xia, Yujian; Feng, Xuefei

Here, we describe a new experimental technique that allows for soft x-ray spectroscopy studies (~100-1000 eV) of high pressure liquid (~100 bars). We achieve this through a liquid cell with a 100 nm-thick Si 3N 4 membrane window, which is sandwiched by two identical O-rings for vacuum sealing. The thin Si 3N 4 membrane allows soft x-rays to penetrate, while separating the high-pressure liquid under investigation from the vacuum required for soft x-ray transmission and detection. The burst pressure of the Si 3N 4 membrane increases with decreasing size and more specifically is inversely proportional to the side length ofmore » the square window. It also increases proportionally with the membrane thickness. Pressures > 60 bars could be achieved for 100 nm-thick square Si 3N 4 windows that are smaller than 65 μm. However, above a certain pressure, the failure of the Si wafer becomes the limiting factor. The failure pressure of the Si wafer is sensitive to the wafer thickness. Moreover, the deformation of the Si 3N 4 membrane is quantified using vertical scanning interferometry. As an example of the performance of the high-pressure liquid cell optimized for total-fluorescence detected soft x-ray absorption spectroscopy (sXAS), the sXAS spectra at the Ca L edge (~350 eV) of a CaCl 2 aqueous solution are collected under different pressures up to 41 bars.« less

Soft x-ray spectroscopy of high pressure liquid

DOE PAGES

Qiao, Ruimin; Xia, Yujian; Feng, Xuefei; ...

2018-01-01

Here, we describe a new experimental technique that allows for soft x-ray spectroscopy studies (~100-1000 eV) of high pressure liquid (~100 bars). We achieve this through a liquid cell with a 100 nm-thick Si 3N 4 membrane window, which is sandwiched by two identical O-rings for vacuum sealing. The thin Si 3N 4 membrane allows soft x-rays to penetrate, while separating the high-pressure liquid under investigation from the vacuum required for soft x-ray transmission and detection. The burst pressure of the Si 3N 4 membrane increases with decreasing size and more specifically is inversely proportional to the side length ofmore » the square window. It also increases proportionally with the membrane thickness. Pressures > 60 bars could be achieved for 100 nm-thick square Si 3N 4 windows that are smaller than 65 μm. However, above a certain pressure, the failure of the Si wafer becomes the limiting factor. The failure pressure of the Si wafer is sensitive to the wafer thickness. Moreover, the deformation of the Si 3N 4 membrane is quantified using vertical scanning interferometry. As an example of the performance of the high-pressure liquid cell optimized for total-fluorescence detected soft x-ray absorption spectroscopy (sXAS), the sXAS spectra at the Ca L edge (~350 eV) of a CaCl 2 aqueous solution are collected under different pressures up to 41 bars.« less

Reduced Pressure Cabin Testing of the Orion Atmosphere Revitalization Technology

NASA Technical Reports Server (NTRS)

Button, Amy B.; Sweterlitsch, Jeffrey J.

2013-01-01

An amine-based carbon dioxide (CO2) and water vapor sorbent in pressure-swing regenerable beds has been developed by United Technologies Corp. Aerospace Systems (UTAS, formerly Hamilton Sundstrand) and baselined for the Atmosphere Revitalization System for moderate duration missions of the Orion Multipurpose Crew Vehicle (MPCV). In previous years at this conference, reports were presented on extensive Johnson Space Center testing of this technology in a sea-level pressure environment with simulated and actual human metabolic loads in both open and closed-loop configurations. In 2011, the technology was tested in an open cabin-loop configuration at ambient and two sub-ambient pressures to compare the performance of the system to the results of previous tests at ambient pressure. The testing used a human metabolic simulator with a different type of water vapor generation than previously used, which added some unique challenges in the data analysis. This paper summarizes the results of: baseline and some matrix testing at all three cabin pressures, increased vacuum regeneration line pressure testing with a high metabolic load, a set of tests studying CO2 and water vapor co-adsorption effects relative to model-predicted performance, and validation tests of flight project computer model predictions with specific operating conditions.

CO2 exposure at pressure impacts metabolism and stress responses in the model sulfate-reducing bacterium Desulfovibrio vulgaris strain Hildenborough

PubMed Central

Wilkins, Michael J.; Hoyt, David W.; Marshall, Matthew J.; Alderson, Paul A.; Plymale, Andrew E.; Markillie, L. Meng; Tucker, Abby E.; Walter, Eric D.; Linggi, Bryan E.; Dohnalkova, Alice C.; Taylor, Ron C.

2014-01-01

Geologic carbon dioxide (CO2) sequestration drives physical and geochemical changes in deep subsurface environments that impact indigenous microbial activities. The combined effects of pressurized CO2 on a model sulfate-reducing microorganism, Desulfovibrio vulgaris, have been assessed using a suite of genomic and kinetic measurements. Novel high-pressure NMR time-series measurements using 13C-lactate were used to track D. vulgaris metabolism. We identified cessation of respiration at CO2 pressures of 10 bar, 25 bar, 50 bar, and 80 bar. Concurrent experiments using N2 as the pressurizing phase had no negative effect on microbial respiration, as inferred from reduction of sulfate to sulfide. Complementary pressurized batch incubations and fluorescence microscopy measurements supported NMR observations, and indicated that non-respiring cells were mostly viable at 50 bar CO2 for at least 4 h, and at 80 bar CO2 for 2 h. The fraction of dead cells increased rapidly after 4 h at 80 bar CO2. Transcriptomic (RNA-Seq) measurements on mRNA transcripts from CO2-incubated biomass indicated that cells up-regulated the production of certain amino acids (leucine, isoleucine) following CO2 exposure at elevated pressures, likely as part of a general stress response. Evidence for other poorly understood stress responses were also identified within RNA-Seq data, suggesting that while pressurized CO2 severely limits the growth and respiration of D. vulgaris cells, biomass retains intact cell membranes at pressures up to 80 bar CO2. Together, these data show that geologic sequestration of CO2 may have significant impacts on rates of sulfate reduction in many deep subsurface environments where this metabolism is a key respiratory process. PMID:25309528

Localization and superconductivity in (BEDT-TIF) 2Cu[N(CN) 2]Cl: Pressure effect

NASA Astrophysics Data System (ADS)

Sushko, Yu. V.; Bondarenko, V. A.; Petrosov, R. A.; Kushch, N. D.; Yagubskii, E. B.

1991-12-01

At ambient pressure titled salt exhibits the insulating ground state. Superconductivity with T c near 12 K appears at the pressure of 95 bar and under the moderate pressures coexists with the high-temperature semiconducting regime. At 340 bar the metallic behavior of resistance is stabilized in whole temperature range and T c reaches the maximum value (midpoint 12.8 K, onset 13.8 K). Further pressure increasing causes rapid T c decreasing.

Parametric Study of Shear Strength of Concrete Beams Reinforced with FRP Bars

NASA Astrophysics Data System (ADS)

Thomas, Job; Ramadass, S.

2016-09-01

Fibre Reinforced Polymer (FRP) bars are being widely used as internal reinforcement in structural elements in the last decade. The corrosion resistance of FRP bars qualifies its use in severe and marine exposure conditions in structures. A total of eight concrete beams longitudinally reinforced with FRP bars were cast and tested over shear span to depth ratio of 0.5 and 1.75. The shear strength test data of 188 beams published in various literatures were also used. The model originally proposed by Indian Standard Code of practice for the prediction of shear strength of concrete beams reinforced with steel bars IS:456 (Plain and reinforced concrete, code of practice, fourth revision. Bureau of Indian Standards, New Delhi, 2000) is considered and a modification to account for the influence of the FRP bars is proposed based on regression analysis. Out of the 196 test data, 110 test data is used for the regression analysis and 86 test data is used for the validation of the model. In addition, the shear strength of 86 test data accounted for the validation is assessed using eleven models proposed by various researchers. The proposed model accounts for compressive strength of concrete ( f ck ), modulus of elasticity of FRP rebar ( E f ), longitudinal reinforcement ratio ( ρ f ), shear span to depth ratio ( a/ d) and size effect of beams. The predicted shear strength of beams using the proposed model and 11 models proposed by other researchers is compared with the corresponding experimental results. The mean of predicted shear strength to the experimental shear strength for the 86 beams accounted for the validation of the proposed model is found to be 0.93. The result of the statistical analysis indicates that the prediction based on the proposed model corroborates with the corresponding experimental data.

Pop tests of storable biopropellant liquid apogee engine

NASA Astrophysics Data System (ADS)

Kuroda, Yukio; Tadano, Makoto; Sato, Masahiro; Kusaka, Kazuo; Kobayashi, Hideyuki; Iihara, Sigeyasu; Ban, Hiroyuki

1994-10-01

A pressure-fed, blowdown, hydrazine/NTO apogee propulsion system had been selected for the ETS-6. One of the problems encountered during the development of the engine was the occurrence of pops (popping) at the higher operating chamber pressures. Pops are irregular high amplitude pressure pulses. It is generally agreed that pops is a liquid spray/gas two-phase explosion triggered by a local explosion near the jet impingement region. The effects of operating parameters on pops observed in the development tests of the apogee engine for the ETS-6 were inconsistent with those reported earlier for single impingement injectors; pops with the apogee engine injectors was more likely to occur at higher chamber pressures, higher injection velocities, and higher propellant temperatures. Pops data were correlated fairly well in chamber pressures (bar-P(sub c)) vs. fuel Reynolds number (R(sub ef)) plane. However, the range of operating parameters for the above correlation were very narrow since they were obtained during injector screening tests for a particular application to the apogee engine. It was also felt that the above correlation was too simplistic to capture any effect of design parameters of multi-element injectors. In the present study, the demarcation between pops and the pops-free region was determined in broader operating ranges and design parameters. The range of bar-P(sub c) and R(sub ef) was extended by exchanging graphite nozzle throat inserts with different throat diameters. The injectors were carefully selected to obtain effects, if any, of (1) film cooling fraction, (2) secondary mixing, and (3) number of elements and/or fuel orifice diameters. It was found that there was a threshold fuel Reynolds number below which no pops were observed at any chamber pressures and that the pops region curve in the bar-P(sub c)-R(sub ef) plane had two branches: upper branches and lower branches.

Laser ignition of liquid petroleum gas at elevated pressures

NASA Astrophysics Data System (ADS)

Loktionov, E.; Pasechnikov, N.; Telekh, V.

2017-11-01

Recent development of laser spark plugs for internal combustion engines have shown lack of data on laser ignition of fuel mixtures at multi-bar pressures needed for laser pulse energy and focusing optimisation. Methane and hydrogen based mixtures are comparatively well investigated, but propane and butane based ones (LPG), which are widely used in vehicles, are still almost unstudied. Optical breakdown thresholds in gases decrease with pressure increase up to ca. 100 bar, but breakdown is not a sufficient condition for combustion ignition. So minimum ignition energy (MIE) becomes more important for combustion core onset, and its dependency on mixture composition and pressure has several important features. For example, unlike breakdown threshold, is poorly dependent on laser pulse length, at least in pico- and to microsecond range. We have defined experimentally the dependencies of minimum picosecond laser pulse energies (MIE related value) needed for ignition of LPG based mixtures of 1.0 to 1.6 equivalence ratios and pressure of 1.0 to 3.5 bar. In addition to expected values decrease, low-energy flammability range broadening has been found at pressure increase. Laser ignition of LPG in Wankel rotary engine is reported for the first time.

Abdominal Twin Pressure Sensors for the assessment of abdominal injuries in Q dummies: in-dummy evaluation and performance in accident reconstructions.

PubMed

Beillas, Philippe; Alonzo, François; Chevalier, Marie-Christine; Lesire, Philippe; Leopold, Franck; Trosseille, Xavier; Johannsen, Heiko

2012-10-01

The Abdominal Pressure Twin Sensors (APTS) for Q3 and Q6 dummies are composed of soft polyurethane bladders filled with fluid and equipped with pressure sensors. Implanted within the abdominal insert of child dummies, they can be used to detect abdominal loading due to the belt during frontal collisions. In the present study - which is part of the EC funded CASPER project - two versions of APTS (V1 and V2) were evaluated in abdominal belt compression tests, torso flexion test (V1 only) and two series of sled tests with degraded restraint conditions. The results suggest that the two versions have similar responses, and that the pressure sensitivity to torso flexion is limited. The APTS ability to detect abdominal loading in sled tests was also confirmed, with peak pressures typically below 1 bar when the belt loaded only the pelvis and the thorax (appropriate restraint) and values above that level when the abdomen was loaded directly (inappropriate restraint). Then, accident reconstructions performed as part of CASPER and previous EC funded projects were reanalyzed. Selected data from 19 dummies (12 Q6 and 7 Q3) were used to plot injury risk curves. Maximum pressure, maximum pressure rate and their product were all found to be injury predictors. Maximum pressure levels for a 50% risk of AIS3+ were consistent with the levels separating appropriate and inappropriate restraint in the sled tests (e.g. 50% risk of AIS3+ at 1.09 bar for pressure filtered CFC180). Further work is needed to refine the scaling techniques between ages and confirm the risk curves.

Structural Behavior of Concrete Beams Reinforced with Basalt Fiber Reinforced Polymer (BFRP) Bars

NASA Astrophysics Data System (ADS)

Ovitigala, Thilan

The main challenge for civil engineers is to provide sustainable, environmentally friendly and financially feasible structures to the society. Finding new materials such as fiber reinforced polymer (FRP) material that can fulfill the above requirements is a must. FRP material was expensive and it was limited to niche markets such as space shuttles and air industry in the 1960s. Over the time, it became cheaper and spread to other industries such as sporting goods in the 1980-1990, and then towards the infrastructure industry. Design and construction guidelines are available for carbon fiber reinforced polymer (CFRP), aramid fiber reinforced polymer (AFRP) and glass fiber reinforced polymer (GFRP) and they are currently used in structural applications. Since FRP is linear elastic brittle material, design guidelines for the steel reinforcement are not valid for FRP materials. Corrosion of steel reinforcement affects the durability of the concrete structures. FRP reinforcement is identified as an alternative to steel reinforcement in corrosive environments. Although basalt fiber reinforced polymer (BFRP) has many advantages over other FRP materials, but limited studies have been done. These studies didn't include larger BFRP bar diameters that are mostly used in practice. Therefore, larger beam sizes with larger BFRP reinforcement bar diameters are needed to investigate the flexural and shear behavior of BFRP reinforced concrete beams. Also, shear behavior of BFRP reinforced concrete beams was not yet studied. Experimental testing of mechanical properties and bond strength of BFRP bars and flexural and shear behavior of BFRP reinforced concrete beams are needed to include BFRP reinforcement bars in the design codes. This study mainly focuses on the use of BFRP bars as internal reinforcement. The test results of the mechanical properties of BFRP reinforcement bars, the bond strength of BFRP reinforcement bars, and the flexural and shear behavior of concrete beams

High-pressure gas quenching in cold chambers for increased cooling capacity

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

Segerberg, S.; Troell, E.

1996-12-31

Gas quenching for the hardening of steel parts is a lower-pollution alternative to quenching in quenchants such as oil or salt. As the surfaces of the cooled parts remain clean after gas quenching, there is no need to wash them after heat treatment, which reduces the consumption of oils and detergents. The fire risk and ventilation requirements of oil quenching are eliminated. In addition, some trials have shown that gas quenching has a positive effect on distortion, representing a saving in finishing work and thus a reduction in costs. Today, gas quenching is used almost solely in vacuum furnaces. Quenchingmore » is normally performed in the same chamber as heating, which means that besides quenching the batch, the quenching system must also remove heat from the heating elements and insulation of the furnace. Previous trials performed by IVF have shown that gas quenching with helium of ball bearing and carburizing steels (and other steels) in sizes up to 25 mm at pressures up to 20 bar in a vacuum furnace can achieve quenching rates and hardnesses similar to those achieved by hot quenching oils. This quenching performance is not, however, capable of dealing with larger sizes or lower-alloy steels. At IVF`s request, ALD Vacuum Technologies GmbH has developed a cold high-pressure gas quenching chamber that is independent of the furnace. As a result, there is no need to cool insulation or heating elements. Quenching can be carried out in the chamber at pressures of up to 40 bar for helium or up to 10 bar for nitrogen. The quenching chamber has been supplied to IVF, and has been used for experimental quenching of steel test pieces and components. Temperatures have been recorded by using some Inconel 600 test probes, {phi} 12,5 x 60 mm, with thermocouples in their centers.« less

Influence of operating pressure on the biological hydrogen methanation in trickle-bed reactors.

PubMed

Ullrich, Timo; Lindner, Jonas; Bär, Katharina; Mörs, Friedemann; Graf, Frank; Lemmer, Andreas

2018-01-01

In order to investigate the influence of pressures up to 9bar absolute on the productivity of trickle-bed reactors for biological methanation of hydrogen and carbon dioxide, experiments were carried out in a continuously operated experimental plant with three identical reactors. The pressure increase promises a longer residence time and improved mass transfer of H 2 due to higher gas partial pressures. The study covers effects of different pressures on important parameters like gas hourly space velocity, methane formation rate, conversion rates and product gas quality. The methane content of 64.13±3.81vol-% at 1.5bar could be increased up to 86.51±0.49vol-% by raising the pressure to 9bar. Methane formation rates of up to 4.28±0.26m 3 m -3 d -1 were achieved. Thus, pressure increase could significantly improve reactor performance. Copyright © 2017 Elsevier Ltd. All rights reserved.

THE DYNAMICAL RELATIONSHIP BETWEEN THE BAR AND SPIRAL PATTERNS OF NGC 1365

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

Speights, Jason C.; Rooke, Paul C., E-mail: jcspeights@frostburg.edu

2016-07-20

Theories that attempt to explain the dynamical relationship between bar and spiral patterns in galactic disks make different predictions about the radial profile of the pattern speed. These are tested for the H-alpha bar and spiral patterns of NGC 1365. The radial profile of the pattern speed is measured by fitting mathematical models that are based on the Tremaine–Weinberg method. The results show convincing evidence for the bar rotating at a faster rate than the spiral pattern, inconsistent with a global wave mode or a manifold. There is evidence for mode coupling of the bar and spiral patterns at themore » overlap of corotation and inner Lindblad resonances (ILRs), but the evidence is unreliable and inconsistent. The results are the most consistent with the bar and spiral patterns being dynamically distinct features. The pattern speed of the bar begins near an ILR and ends near the corotation resonance (CR). The radial profile of the pattern speed beyond the bar most closely resembles what is expected for coupled spiral modes and tidal interactions.« less

49 CFR 178.255-12 - Pressure test.

Code of Federal Regulations, 2010 CFR

2010-10-01

... Specifications for Portable Tanks § 178.255-12 Pressure test. (a) Each completed portable tank prior to application of lining shall be tested before being put into transportation service by completely filling the...

Application of the BAR score as a predictor of short- and long-term survival in liver transplantation patients.

PubMed

de Campos Junior, Ivan Dias; Stucchi, Raquel Silveira Bello; Udo, Elisabete Yoko; Boin, Ilka de Fátima Santana Ferreira

2015-01-01

The balance of risk (BAR) is a prediction system after liver transplantation. To assess the BAR system, a retrospective observational study was performed in 402 patients who had transplant surgery between 1997 and 2012. The BAR score was computed for each patient. Receiver operating characteristic curve analysis with the Hosmer-Lemeshow test was used to calculate sensitivity, specificity, and model calibration. The cutoff value with the best Youden index was selected. Statistical analysis employed the Kaplan-Meier method (log-rank test) for survival, the Mann-Whitney test for group comparison, and multiple logistic regression analysis. 3-month survival was 46% for BAR ≥ 11 and 77% for BAR <11 (p = 0.001); 12-month survival was 44% for BAR ≥ 11 and 69% for BAR <11 (p = 0.001). Factors of survival <3 months were BAR ≥ 11 [odds ratio (OR) 3.08; 95% confidence interval (CI) 1.75-5.42; p = 0.001] and intrasurgical use of packed red blood cells (RBC) above 6 units (OR 4.49; 95% CI 2.73-7.39; p = 0.001). For survival <12 months, factors were BAR ≥ 11 (OR 2.94; 95% CI 1.67-5.16; p = 0.001) and RBC >6 units (OR 2.99; 95% CI 1.92-4.64; p = 0.001). Our study contributes to the incorporation of the BAR system into Brazilian transplantation centers.

Composite Overwrapped Pressure Vessel (COPV) Stress Rupture Testing

NASA Technical Reports Server (NTRS)

Greene, Nathanael J.; Saulsberry, Regor L.; Leifeste, Mark R.; Yoder, Tommy B.; Keddy, Chris P.; Forth, Scott C.; Russell, Rick W.

2010-01-01

This paper reports stress rupture testing of Kevlar(TradeMark) composite overwrapped pressure vessels (COPVs) at NASA White Sands Test Facility. This 6-year test program was part of the larger effort to predict and extend the lifetime of flight vessels. Tests were performed to characterize control parameters for stress rupture testing, and vessel life was predicted by statistical modeling. One highly instrumented 102-cm (40-in.) diameter Kevlar(TradeMark) COPV was tested to failure (burst) as a single-point model verification. Significant data were generated that will enhance development of improved NDE methods and predictive modeling techniques, and thus better address stress rupture and other composite durability concerns that affect pressure vessel safety, reliability and mission assurance.

The influence of a hyperbaric environment and increased oxygen partial pressure on the corrosion of dental alloys.

PubMed

Mehl, Christian; Heblich, Frank; Lenz, Rudolf; Ludwig, Klaus; Kern, Matthias

2011-09-01

The purpose of this in-vitro study was to determine whether there is a correlation between a hyperbaric environment or increased oxygen partial pressure and the corrosion of dental alloys used for dental restorations in divers. Samples of three commercially available dental alloys (palladium-based, reduced-gold-content and high-gold-content) were tested in the DIN EN ISO 1562 static immersion test and the amount of dissolved ions measured by atomic absorption spectrometry. The specimens were exposed to one of the following three conditions: normobaric and normoxic conditions (PO2 21 kPa); 608 kPa (6 bar, PO2 127 kPa) pressurised air in a pressure chamber or 506 kPa (5 bar, PO2 304 kPa) pressurised nitrox in a pressure chamber. None of the exposures suggested a correlation between increased ion solubility as a measure of corrosion and increased ambient pressure of the three alloys. The reduced-gold-content alloy released zinc ions at twice the weekly recommended dose. When the palladium-based alloy was exposed to a hyperbaric or hyperbaric/hyperoxic environment, ion solubility increased only slightly for gallium and silver. Within the limited sample size of the current study it can be concluded that hyperbaric and/or hyperoxic conditions do not seem to be a risk for increased corrosion for any of the three tested alloys.

Subsurface fluid pressures from drill-stem tests, Uinta Basin, Utah

USGS Publications Warehouse

Nelson, P.H.

2002-01-01

High fluid pressures are known to be associated with oil and gas fields in the Uinta Basin, Utah. Shut-in pressure measurements from drill-stem tests show how pressure varies with depth and by area within the basin. The data base used in this report incorporates over 2,000 pressure measurements from drill-stem tests in wells completed prior to 1985. However, the number of useful pressure measurements is considerably less, because many drill-stem tests fail to stabilize at the actual formation pressure if the permeability is low. By extracting the maximum pressure measurements recorded in a collection of wells within an area, the trend of formation pressure within that area can be approximated. Areal compilations of pressures from drill-stem tests show that overpressured rock formations occur throughout much of the northern and eastern areas of the Uinta Basin. In particular, significant overpressuring (0.5 < pressure gradient < 0.8 psi/ft) is found throughout much of the Altamont-Bluebell field at depths ranging from 10,000 to 13,000 ft, equivalent to 5,000 to 8,000 ft below sea level. Limited data indicate that the pressure gradient declines at depths greater than 13,000 ft. An underpressured zone appears to exist in the Altamont-Bluebell field at depths shallower than 5,000 ft. Throughout the eastern Uinta Basin, moderately overpressured zones (0.46 < pressure gradient < 0.5 psi/ft) are common, with local evidence of significantly overpressured zones, but pressure gradients greater than 0.6 psi/ft are rare.

SOL Tests Create Unfair Pressure.

ERIC Educational Resources Information Center

Ernst, Katie

2000-01-01

A seventh-grader explains why the Virginia Standards of Learning tests unfairly pressure her and her teachers. She wants her free reading time restored and wishes politicians would worry more about students understanding--not just memorizing--facts. She praises teachers who go beyond the SOL. (MLH)

Water permeability of nanoporous graphene at realistic pressures for reverse osmosis desalination

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

Cohen-Tanugi, David; Grossman, Jeffrey C.

Nanoporous graphene (NPG) shows tremendous promise as an ultra-permeable membrane for water desalination thanks to its atomic thickness and precise sieving properties. However, a significant gap exists in the literature between the ideal conditions assumed for NPG desalination and the physical environment inherent to reverse osmosis (RO) systems. In particular, the water permeability of NPG has been calculated previously based on very high pressures (1000–2000 bars). Does NPG maintain its ultrahigh water permeability under real-world RO pressures (<100 bars)? Here, we answer this question by drawing results from molecular dynamics simulations. Our results indicate that NPG maintains its ultrahigh permeabilitymore » even at low pressures, allowing a permeate water flux of 6.0 l/h-bar per pore, or equivalently 1041 ± 20 l/m{sup 2}-h-bar assuming a nanopore density of 1.7 × 10{sup 13} cm{sup −2}.« less

Comparison of the passivity between cast alloy and laser-welded titanium overdenture bars.

PubMed

Paiva, Jose; Givan, Daniel A; Broome, James C; Lemons, Jack E; McCracken, Michael S

2009-12-01

The purpose of this study was to investigate the fit of cast alloy overdenture and laser-welded titanium-alloy bars by measuring induced strain upon tightening of the bars on a master cast as well as a function of screw tightening sequence. Four implant analogs were secured into Type IV dental stone to simulate a mandibular edentulous patient cast, and two groups of four overdenture bars were fabricated. Group I was four cast alloy bars and Group II was four laser-welded titanium bars. The cast alloy bars included Au-Ag-Pd, Pd-Ag-Au, Au-Ag-Cu-Pd, and Ag-Pd-Cu-Au, while the laser-welded bars were all Ti-Al-V alloy. Bars were made from the same master cast, were torqued into place, and the total strain in the bars was measured through five strain gauges bonded to the bar between the implants. Each bar was placed and torqued 27 times to 30 Ncm per screw using three tightening sequences. Data were processed through a strain amplifier and analyzed by computer using StrainSmart software. Data were analyzed by ANOVA and Tukey's post hoc test. Significant differences were found between alloy types. Laser-welded titanium bars tended to have lower strains than corresponding cast bars, although the Au-Ag-Pd bar was not significantly different. The magnitudes of total strain were the least when first tightening the ends of the bar. The passivity of implant overdenture bars was evaluated using total strain of the bar when tightening. Selecting a high modulus of elasticity cast alloy or use of laser-welded bar design resulted in the lowest average strain magnitudes. While the effect of screw tightening sequence was minimal, tightening the distal ends first demonstrated the lowest strain, and hence the best passivity.

Blood pressure and neuropsychological test performance in healthy postmenopausal women.

PubMed

Alsumali, Adnan; Mekary, Rania A; Seeger, John; Regestein, Quentin

2016-06-01

To study the association between blood pressure and neuropsychological test performance in healthy postmenopausal women. Data from 88 healthy postmenopausal women aged 46-73 years, who were not experiencing hot flashes, and who had participated in a prior drug trial, were analyzed to find whether baseline blood pressure was associated with impaired performance on neuropsychological testing done at 3 follow-up visits separated by 4 weeks. Factor analysis was used to reduce the dimensions of neuropsychological test performance. Mixed linear modeling was used to evaluate the association between baseline blood pressure and repeatedly measured neuropsychological test performance at follow-up in a complete case analysis (n=53). In a sensitivity analysis (n=88), multiple-imputation using the Markov Chain Monte Carlo method was used to account for missing data (blood pressure results) for some visits. The variables recording neuropsychological test performance were reduced to two main factors (Factor 1=selective attention; Factor 2=complex processing). In the complete case analysis, the association between a 20-mmHg increase in diastolic blood pressure and Factor 1 remained statistically significant after adjusting for potential confounders, before adjusting for systolic blood pressure (slope=0.60; 95%CI=0.04,1.16), and after adjusting for systolic blood pressure (slope=0.76; 95%CI=0.06, 1.47). The positive slopes indicated an increase in the time spent performing a given task (i.e., a decrease in neuropsychological test performance). No other significant associations were found between systolic blood pressure and either factor. The results did not materially change after applying the multiple-imputation method. An increase in diastolic blood pressure was associated with a decrease in neuropsychological test performance among older healthy postmenopausal women experiencing hot flashes. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Pressure and temperature fields associated with aero-optics tests. [transonic wind tunnel tests

NASA Technical Reports Server (NTRS)

Raman, K. R.

1980-01-01

The experimental investigation carried out in a 6 x 6 ft wind tunnel on four model configurations in the aero-optics series of tests are described. The data obtained on the random pressures (static and total pressures) and total temperatures are presented. In addition, the data for static pressure fluctuations on the Coelostat turret model are presented. The measurements indicate that the random pressures and temperature are negligible compared to their own mean (or steady state) values for the four models considered, thus allowing considerable simplification in the calculations to obtain the statistical properties of the density field. In the case of the Coelostat model tests these simplifications cannot be assumed a priori and require further investigation.

Dynamic tensile characterization of a 4330-V steel with kolsky bar techniques.

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

Song, Bo; Antoun, Bonnie R.; Connelly, Kevin

2010-09-01

There has been increasing demand to understand the stress-strain response as well as damage and failure mechanisms of materials under impact loading condition. Dynamic tensile characterization has been an efficient approach to acquire satisfactory information of mechanical properties including damage and failure of the materials under investigation. However, in order to obtain valid experimental data, reliable tensile experimental techniques at high strain rates are required. This includes not only precise experimental apparatus but also reliable experimental procedures and comprehensive data interpretation. Kolsky bar, originally developed by Kolsky in 1949 [1] for high-rate compressive characterization of materials, has been extended formore » dynamic tensile testing since 1960 [2]. In comparison to Kolsky compression bar, the experimental design of Kolsky tension bar has been much more diversified, particularly in producing high speed tensile pulses in the bars. Moreover, instead of directly sandwiching the cylindrical specimen between the bars in Kolsky bar compression bar experiments, the specimen must be firmly attached to the bar ends in Kolsky tensile bar experiments. A common method is to thread a dumbbell specimen into the ends of the incident and transmission bars. The relatively complicated striking and specimen gripping systems in Kolsky tension bar techniques often lead to disturbance in stress wave propagation in the bars, requiring appropriate interpretation of experimental data. In this study, we employed a modified Kolsky tension bar, newly developed at Sandia National Laboratories, Livermore, CA, to explore the dynamic tensile response of a 4330-V steel. The design of the new Kolsky tension bar has been presented at 2010 SEM Annual Conference [3]. Figures 1 and 2 show the actual photograph and schematic of the Kolsky tension bar, respectively. As shown in Fig. 2, the gun barrel is directly connected to the incident bar with a coupler. The

High pressure furnace

DOEpatents

Morris, D.E.

1993-09-14

A high temperature high pressure furnace has a hybrid partially externally heated construction. A metallic vessel fabricated from an alloy having a composition of at least 45% nickel, 15% chrome, and 10% tungsten is utilized (the preferred alloy including 55% nickel, 22% chrome, 14% tungsten, 2% molybdenum, 3% iron (maximum) and 5% cobalt (maximum)). The disclosed alloy is fabricated into 11/4 or 2 inch, 32 mm or 50 mm bar stock and has a length of about 22 inches, 56 cm. This bar stock has an aperture formed therein to define a closed high temperature, high pressure oxygen chamber. The opposite and closed end of the vessel is provided with a small blind aperture into which a thermocouple can be inserted. The closed end of the vessel is inserted into an oven, preferably heated by standard nickel chrome electrical elements and having a heavily insulated exterior. 19 figures.

High pressure furnace

DOEpatents

Morris, Donald E.

1993-01-01

A high temperature high pressure furnace has a hybrid partially externally heated construction. A metallic vessel fabricated from an alloy having a composition of at least 45% nickel, 15% chrome, and 10% tungsten is utilized (the preferred alloy including 55% nickel, 22% chrome, 14% tungsten, 2% molybdenum, 3% iron (maximum) and 5% cobalt (maximum). The disclosed alloy is fabricated into 11/4 or 2 inch, 32 mm or 50 mm bar stock and has a length of about 22 inches, 56 cm. This bar stock has an aperture formed therein to define a closed high temperature, high pressure oxygen chamber. The opposite and closed end of the vessel is provided with a small blind aperture into which a thermocouple can be inserted. The closed end of the vessel is inserted into an oven, preferably heated by standard nickel chrome electrical elements and having a heavily insulated exterior.

Bar quenching in gas-rich galaxies

NASA Astrophysics Data System (ADS)

Khoperskov, S.; Haywood, M.; Di Matteo, P.; Lehnert, M. D.; Combes, F.

2018-01-01

Galaxy surveys have suggested that rapid and sustained decrease in the star-formation rate (SFR), "quenching", in massive disk galaxies is frequently related to the presence of a bar. Optical and near-IR observations reveal that nearly 60% of disk galaxies in the local universe are barred, thus it is important to understand the relationship between bars and star formation in disk galaxies. Recent observational results imply that the Milky Way quenched about 9-10 Gyr ago, at the transition between the cessation of the growth of the kinematically hot, old, metal-poor thick disk and the kinematically colder, younger, and more metal-rich thin disk. Although perhaps coincidental, the quenching episode could also be related to the formation of the bar. Indeed the transfer of energy from the large-scale shear induced by the bar to increasing turbulent energy could stabilize the gaseous disk against wide-spread star formation and quench the galaxy. To explore the relation between bar formation and star formation in gas rich galaxies quantitatively, we simulated gas-rich disk isolated galaxies. Our simulations include prescriptions for star formation, stellar feedback, and for regulating the multi-phase interstellar medium. We find that the action of stellar bar efficiently quenches star formation, reducing the star-formation rate by a factor of ten in less than 1 Gyr. Analytical and self-consistent galaxy simulations with bars suggest that the action of the stellar bar increases the gas random motions within the co-rotation radius of the bar. Indeed, we detect an increase in the gas velocity dispersion up to 20-35 km s-1 at the end of the bar formation phase. The star-formation efficiency decreases rapidly, and in all of our models, the bar quenches the star formation in the galaxy. The star-formation efficiency is much lower in simulated barred compared to unbarred galaxies and more rapid bar formation implies more rapid quenching.

Star formation suppression and bar ages in nearby barred galaxies

NASA Astrophysics Data System (ADS)

James, P. A.; Percival, S. M.

2018-03-01

We present new spectroscopic data for 21 barred spiral galaxies, which we use to explore the effect of bars on disc star formation, and to place constraints on the characteristic lifetimes of bar episodes. The analysis centres on regions of heavily suppressed star formation activity, which we term `star formation deserts'. Long-slit optical spectroscopy is used to determine H β absorption strengths in these desert regions, and comparisons with theoretical stellar population models are used to determine the time since the last significant star formation activity, and hence the ages of the bars. We find typical ages of ˜1 Gyr, but with a broad range, much larger than would be expected from measurement errors alone, extending from ˜0.25 to >4 Gyr. Low-level residual star formation, or mixing of stars from outside the `desert' regions, could result in a doubling of these age estimates. The relatively young ages of the underlying populations coupled with the strong limits on the current star formation rule out a gradual exponential decline in activity, and hence support our assumption of an abrupt truncation event.

Creation and validation of the barriers to alcohol reduction (BAR) scale using classical test theory and item response theory.

PubMed

Kunicki, Zachary J; Schick, Melissa R; Spillane, Nichea S; Harlow, Lisa L

2018-06-01

Those who binge drink are at increased risk for alcohol-related consequences when compared to non-binge drinkers. Research shows individuals may face barriers to reducing their drinking behavior, but few measures exist to assess these barriers. This study created and validated the Barriers to Alcohol Reduction (BAR) scale. Participants were college students ( n  = 230) who endorsed at least one instance of past-month binge drinking (4+ drinks for women or 5+ drinks for men). Using classical test theory, exploratory structural equation modeling found a two-factor structure of personal/psychosocial barriers and perceived program barriers. The sub-factors, and full scale had reasonable internal consistency (i.e., coefficient omega = 0.78 (personal/psychosocial), 0.82 (program barriers), and 0.83 (full measure)). The BAR also showed evidence for convergent validity with the Brief Young Adult Alcohol Consequences Questionnaire ( r  = 0.39, p  < .001) and discriminant validity with Barriers to Physical Activity ( r  = -0.02, p  = .81). Item Response Theory (IRT) analysis showed the two factors separately met the unidimensionality assumption, and provided further evidence for severity of the items on the two factors. Results suggest that the BAR measure appears reliable and valid for use in an undergraduate student population of binge drinkers. Future studies may want to re-examine this measure in a more diverse sample.

Magnetic Polarizability of Virtual (s\\bar{s}) and (c\\bar{c}) Pairs in the Nucleon

NASA Astrophysics Data System (ADS)

Filip, Peter

2017-12-01

We suggest 3 P 0 quantum state of virtual (s\\bar{s}) pairs in the nucleon can be polarised by the internal fields permeating the volume of the nucleon (proton or neutron). Due to the quadratic Zeeman interaction, 3 P 0 wavefunction of virtual (q\\bar{q}) pairs acquires the admixture of 1 P 10 quantum state in the magnetic field, which generates the antiparallel polarization of s and \\bar{s} quarks (in the nucleon). Considering the internal magnetic fields of neutron and proton (originating from their measured magnetic dipole moments), we suggest the induced s-quark polarization in the neutron to be of the oposite direction compared to the proton case. We mention the influence of the internal chromo-magnetic fields on the quantum state of (q\\bar{q}) pairs in the nucleon and we discuss also the expected behaviour of virtual (c\\bar{c}) pairs.

Pseudolinear gradient ultrahigh-pressure liquid chromatography using an injection valve assembly.

PubMed

Xiang, Yanqiao; Liu, Yansheng; Stearns, Stanley D; Plistil, Alex; Brisbin, Martin P; Lee, Milton L

2006-02-01

The use of ultrahigh pressures in liquid chromatography (UHPLC) imposes stringent requirements on hardware such as pumps, valves, injectors, connecting tubing, and columns. One of the most difficult components of the UHPLC system to develop has been the sample injector. Static-split injection, which can be performed at pressures up to 6900 bar (100,000 psi), consumes a large sample volume and is very irreproducible. A pressure-balanced injection valve provided better reproducibility, shorter injection time, reduced sample consumption, and greater ease of use; however, it could only withstand pressures up to approximately 1000 bar (15,000 psi). In this study, a new injection valve assembly that can operate at pressures as high as 2070 bar (30,000 psi) was evaluated for UHPLC. This assembly contains six miniature electronically controlled needle valves to provide accurate and precise volumes for introduction into the capillary LC column. It was found that sample volumes as small as several tenths of a nanoliter can be injected, which are comparable to the results obtained from the static-split injector. The reproducibilities of retention time, efficiency, and peak area were investigated, and the results showed that the relative standard deviations of these parameters were small enough for quantitative analyses. Separation experiments using the UHPLC system with this new injection valve assembly showed that this new injector is suitable for both isocratic and gradient operation modes. A newly designed capillary connector was used at a pressure as high as 2070 bar (30,000 psi).

Galaxy Zoo: finding offset discs and bars in SDSS galaxies★

NASA Astrophysics Data System (ADS)

Kruk, Sandor J.; Lintott, Chris J.; Simmons, Brooke D.; Bamford, Steven P.; Cardamone, Carolin N.; Fortson, Lucy; Hart, Ross E.; Häußler, Boris; Masters, Karen L.; Nichol, Robert C.; Schawinski, Kevin; Smethurst, Rebecca J.

2017-08-01

We use multiwavelength Sloan Digital Sky Survey (SDSS) images and Galaxy Zoo morphologies to identify a sample of ˜270 late-type galaxies with an off-centre bar. We measure offsets in the range 0.2-2.5 kpc between the photometric centres of the stellar disc and stellar bar. The measured offsets correlate with global asymmetries of the galaxies, with those with largest offsets showing higher lopsidedness. These findings are in good agreement with predictions from simulations of dwarf-dwarf tidal interactions producing off-centre bars. We find that the majority of galaxies with off-centre bars are of Magellanic type, with a median mass of 109.6 M⊙, and 91 per cent of them having M⋆ < 3 × 1010 M⊙, the characteristic mass at which galaxies start having higher central concentrations attributed to the presence of bulges. We conduct a search for companions to test the hypothesis of tidal interactions, but find that a similar fraction of galaxies with offset bars have companions within 100 kpc as galaxies with centred bars. Although this may be due to the incompleteness of the SDSS spectroscopic survey at the faint end, alternative scenarios that give rise to offset bars such as interactions with dark companions or the effect of lopsided halo potentials should be considered. Future observations are needed to confirm possible low-mass companion candidates and to determine the shape of the dark matter halo, in order to find the explanation for the off-centre bars in these galaxies.

Implant-retained mandibular bar-supported overlay dentures: a finite element stress analysis of four different bar heights.

PubMed

Rismanchian, Mansoor; Dakhilalian, Mansour; Bajoghli, Farshad; Ghasemi, Ehsan; Sadr-Eshkevari, Pooyan

2012-04-01

Proper stress distribution on dental implants is necessary in bar-retained implant overlay dentures. We aimed to comparatively assess this stress distribution according to different bar heights using finite element models. A three-dimensional (3D) computer model of mandible with 2 implants (ITI, 4.1 mm diameter and 12 mm length) in canine areas and an overlying implant-supported bar-retained overlay denture were simulated with 0-, 1-, 2-, and 3-mm bar heights using ABAQUS software. A vertical force was applied to the left first molar and gradually increased from 0 to 50 N. The resultant stress distribution was evaluated. Bars of 1 and 2 mm in height transferred the least stress to the implants (3.882 and 3.896 MPa, respectively). The 0-mm height of the bar connection transferred the highest stress value (4.277 MPa). The amount of stress transferred by 3-mm heights of the bar connection was greater than that of 1- and 2-mm bar connections and smaller than that of 0-mm bar connection (4.165 kgN). This 3D finite element analysis study suggested that the use of Dolder bar attachment with 1- and 2-mm heights could be associated with appropriate stress distribution for implant-retained overlay dentures.

30 CFR 7.307 - Static pressure test.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Static pressure test. 7.307 Section 7.307 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR TESTING, EVALUATION, AND APPROVAL OF MINING PRODUCTS TESTING BY APPLICANT OR THIRD PARTY Electric Motor Assemblies § 7.307 Static...

30 CFR 18.67 - Static-pressure tests.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Static-pressure tests. 18.67 Section 18.67 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR TESTING, EVALUATION, AND APPROVAL OF MINING PRODUCTS ELECTRIC MOTOR-DRIVEN MINE EQUIPMENT AND ACCESSORIES Inspections and Tests § 18...

Stress analysis of mandibular implant overdenture with locator and bar/clip attachment: Comparative study with differences in the denture base length.

PubMed

Yoo, Jin Suk; Kwon, Kung-Rock; Noh, Kwantae; Lee, Hyeonjong; Paek, Janghyun

2017-06-01

The design of the attachment must provide an optimum stress distribution around the implant. In this study, for implant overdentures with a bar/clip attachment or a locator attachment, the stress transmitted to the implant in accordance with the change in the denture base length and the vertical pressure was measured and analyzed. Test model was created with epoxy resin. The strain gauges made a tight contact with implant surfaces. A universal testing machine was used to exert a vertical pressure on the mandibular implant overdenture and the strain rate of the implants was measured. Means and standard deviations of the maximum micro-deformation rates were determined. 1) Locator attachment: The implants on the working side generally showed higher strain than those on the non-working side. Tensile force was observed on the mesial surface of the implant on the working side, and the compressive force was applied to the buccal surface and on the surfaces of the implant on the non-working side. 2) Bar/clip attachment: The implants on the both non-working and working sides showed high strain; all surfaces except the mesial surface of the implant on the non-working side showed a compressive force. To minimize the strain on implants in mandibular implant overdentures, the attachment of the implant should be carefully selected and the denture base should be extended as much as possible.

33 CFR 183.580 - Static pressure test for fuel tanks.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 33 Navigation and Navigable Waters 2 2012-07-01 2012-07-01 false Static pressure test for fuel... SECURITY (CONTINUED) BOATING SAFETY BOATS AND ASSOCIATED EQUIPMENT Fuel Systems Tests § 183.580 Static pressure test for fuel tanks. A fuel tank is tested by performing the following procedures in the following...

33 CFR 183.580 - Static pressure test for fuel tanks.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 33 Navigation and Navigable Waters 2 2013-07-01 2013-07-01 false Static pressure test for fuel... SECURITY (CONTINUED) BOATING SAFETY BOATS AND ASSOCIATED EQUIPMENT Fuel Systems Tests § 183.580 Static pressure test for fuel tanks. A fuel tank is tested by performing the following procedures in the following...

33 CFR 183.580 - Static pressure test for fuel tanks.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 33 Navigation and Navigable Waters 2 2014-07-01 2014-07-01 false Static pressure test for fuel... SECURITY (CONTINUED) BOATING SAFETY BOATS AND ASSOCIATED EQUIPMENT Fuel Systems Tests § 183.580 Static pressure test for fuel tanks. A fuel tank is tested by performing the following procedures in the following...

33 CFR 183.580 - Static pressure test for fuel tanks.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 33 Navigation and Navigable Waters 2 2011-07-01 2011-07-01 false Static pressure test for fuel... SECURITY (CONTINUED) BOATING SAFETY BOATS AND ASSOCIATED EQUIPMENT Fuel Systems Tests § 183.580 Static pressure test for fuel tanks. A fuel tank is tested by performing the following procedures in the following...

33 CFR 183.580 - Static pressure test for fuel tanks.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Static pressure test for fuel... SECURITY (CONTINUED) BOATING SAFETY BOATS AND ASSOCIATED EQUIPMENT Fuel Systems Tests § 183.580 Static pressure test for fuel tanks. A fuel tank is tested by performing the following procedures in the following...

Testing of selected metallic reinforcing bars for extending the service life of future concrete bridges : summary of conclusions and recommendations.

DOT National Transportation Integrated Search

2002-01-01

This report summarizes the major conclusions drawn from its companion reports, which described investigations conducted using a stainless steel-clad bar, selected stainless steel bars (304, 316LN, and duplex 2205), and a carbon steel bar in concrete ...

One Reading Specialist's Response to High-Stakes Testing Pressures

ERIC Educational Resources Information Center

Assaf, Lori

2006-01-01

Pressures to help students pass high-stakes tests affect teachers' reading instruction, their responsiveness to students' learning needs, and their professional effectiveness. This article reports on how one reading specialist responded to testing pressures in her urban elementary school. She believed that what was "right" for her…

33 CFR 159.111 - Pressure and vacuum pulse test.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 33 Navigation and Navigable Waters 2 2011-07-01 2011-07-01 false Pressure and vacuum pulse test. 159.111 Section 159.111 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) POLLUTION MARINE SANITATION DEVICES Design, Construction, and Testing § 159.111 Pressure and...

A Kolsky tension bar technique using a hollow incident tube

NASA Astrophysics Data System (ADS)

Guzman, O.; Frew, D. J.; Chen, W.

2011-04-01

Load control of the incident pulse profiles in compression Kolsky bar experiments has been widely used to subject the specimen to optimal testing conditions. Tension Kolsky bars have been used to determine dynamic material behavior since the 1960s with limited capability to shape the loading pulses due to the pulse-generating mechanisms. We developed a modified Kolsky tension bar where a hollow incident tube is used to carry the incident stress waves. The incident tube also acts as a gas gun barrel that houses the striker for impact. The main advantage of this new design is that the striker impacts on an impact cap of the incident tube. Compression pulse shapers can be attached to the impact cap, thus fully utilizing the predictive compression pulse-shaping capability in tension experiments. Using this new testing technique, the dynamic tensile material behavior for Al 6061-T6511 and TRIP 800 (transformation-induced plasticity) steel has been obtained.

Absorption of infrared radiation by carbon monoxide at elevated temperatures and pressures: Part B. Total emissivity charts and correlations

NASA Astrophysics Data System (ADS)

Alberti, Michael; Weber, Roman; Mancini, Marco

2017-10-01

The line-by-line procedure developed in the associated paper (Part A ) has been used to generate the total emissivity chart for pure CO and CO -N2 /air mixtures at 1 bar total pressure, in the 300 to 3000 K temperature and 0.01 to 3000 bar cm pressure path length range. Methods of scaling the emissivity to pressures different to 1 bar, in the range 0.1 to 40 bar, are provided through pressure correction graphs and EXCEL interpolator (Supplementary Material). The interpolated emissivities are within ± 2% margin from the line-by-line calculated values. The newly developed emissivity graphs are substantially more accurate than the existing Ulrich (1936) & Hottel (1954) and Abu-Romia & Tien (1966) charts.

Chloride-induced corrosion mechanism and rate of enamel- and epoxy-coated deformed steel bars embedded in mortar

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

Tang, Fujian; Chen, Genda; Brow, Richard K.

The chloride-induced corrosion mechanisms of uncoated, pure enamel (PE)-coated, mixed enamel (ME)-coated, double enamel (DE)-coated, and fusion bonded epoxy (FBE)-coated deformed steel bars embedded in mortar cylinders are investigated in 3.5 wt.% NaCl solution and compared through electrochemical tests and visual inspection. Corrosion initiated after 29 or 61 days of tests in all uncoated and enamel-coated steel bars, and after 244 days of tests in some FBE-coated steel bars. In active stage, DE- and FBE-coated steel bars are subjected to the highest and lowest corrosion rates, respectively. The uncoated and ME-coated steel bars revealed relatively uniform corrosion while the PE-,more » DE-, and FBE-coated steel bars experienced pitting corrosion around damaged coating areas. Due to the combined effect of ion diffusion and capillary suction, wet–dry cyclic immersion caused more severe corrosion than continuous immersion. Both exposure conditions affected the corrosion rate more significantly than the water–cement ratio in mortar design.« less

49 CFR 179.500-16 - Tests of pressure relief devices.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 49 Transportation 2 2010-10-01 2010-10-01 false Tests of pressure relief devices. 179.500-16... FOR TANK CARS Specification for Cryogenic Liquid Tank Car Tanks and Seamless Steel Tanks (Classes DOT-113 and 107A) § 179.500-16 Tests of pressure relief devices. (a) Pressure relief valves shall be...

Acute muscular strength assessment using free weight bars of different thickness.

PubMed

Ratamess, Nicholas A; Faigenbaum, Avery D; Mangine, Gerald T; Hoffman, Jay R; Kang, Jie

2007-02-01

The purpose of the present investigation was to examine strength performance of 6 common resistance training exercises using free weight bars of different thickness. Eleven resistance-trained men (8.2 +/- 2.6 years of experience; age: 22.1 +/- 1.6 years; body mass: 90.5 +/- 8.9 kg) underwent 1 repetition maximum (1RM) strength testing on 6 occasions in random order for the deadlift, bent-over row, upright row, bench press, seated shoulder press, and arm curl exercises under 3 conditions using: (a) a standard Olympic bar (OL), (b) a 2-inch thick bar (5.08 cm grip span), and (c) a 3-inch thick bar (7.62 cm grip span). Significant (p < 0.05) interactions were observed for the "pulling" exercises. For the deadlift and bent-over row, highest 1RM values were obtained with OL, followed by the 2- and 3-inch bar. Significant 1RM performance decrements for the 2- and 3-inch bars were approximately 28.3 and 55.0%, respectively, for the deadlift; decrements for the 2- and 3-inch bars were approximately 8.9 and 37.3%, respectively, for the bent-over row. For the upright row and arm curl, similar 1RMs were obtained for OL and the 2-inch bar. However, a significant performance reduction was observed using the 3-inch bar (approximately 26.1% for the upright row and 17.6% for the arm curl). The reductions in 1RM loads correlated significantly to hand size and maximal isometric grip strength (r = -0.55 to -0.73). No differences were observed between bars for the bench press or shoulder press. In conclusion, the use of 2- and 3-inch thick bars may result in initial weight reductions primarily for pulling exercises presumably due to greater reliance on maximal grip strength and larger hand size.

Galaxy Zoo: Observing secular evolution through bars

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

Cheung, Edmond; Faber, S. M.; Koo, David C.

In this paper, we use the Galaxy Zoo 2 data set to study the behavior of bars in disk galaxies as a function of specific star formation rate (SSFR) and bulge prominence. Our sample consists of 13,295 disk galaxies, with an overall (strong) bar fraction of 23.6% ± 0.4%, of which 1154 barred galaxies also have bar length (BL) measurements. These samples are the largest ever used to study the role of bars in galaxy evolution. We find that the likelihood of a galaxy hosting a bar is anticorrelated with SSFR, regardless of stellar mass or bulge prominence. We findmore » that the trends of bar likelihood and BL with bulge prominence are bimodal with SSFR. We interpret these observations using state-of-the-art simulations of bar evolution that include live halos and the effects of gas and star formation. We suggest our observed trends of bar likelihood with SSFR are driven by the gas fraction of the disks, a factor demonstrated to significantly retard both bar formation and evolution in models. We interpret the bimodal relationship between bulge prominence and bar properties as being due to the complicated effects of classical bulges and central mass concentrations on bar evolution and also to the growth of disky pseudobulges by bar evolution. These results represent empirical evidence for secular evolution driven by bars in disk galaxies. This work suggests that bars are not stagnant structures within disk galaxies but are a critical evolutionary driver of their host galaxies in the local universe (z < 1).« less

Force and pressure tests of the GA(W)-1 airfoil with a 20% aileron and pressure tests with a 30% Fowler flap

NASA Technical Reports Server (NTRS)

Wentz, W. H., Jr.; Seetharam, H. C.; Fiscko, K. A.

1977-01-01

Wind tunnel force and pressure tests were conducted for the GA(W)-1 airfoil equipped with a 20% aileron, and pressure tests were conducted with a 30% Fowler flap. All tests were conducted at a Reynolds number of 2.2 and a Mach number of 0.13. The aileron provides control effectiveness similar to ailerons applied to more conventional airfoils. Effects of aileron gaps from 0% to 2% chord were evaluated, as well as hinge moment characteristics. The aft camber of the GA(W)-1 section results in a substantial up-aileron moment, but the hinge moments associated with aileron deflection are similar to other configurations. Fowler flap pressure distributions indicate that unseparated flow is achieved for flap settings up to 40 deg., over a limited angle of attack range. Theoretical pressure distributions compare favorably with experiments for low flap deflections, but show substantial errors at large deflections.

Composite Overwrapped Pressure Vessels (COPV) Stress Rupture Test

NASA Technical Reports Server (NTRS)

Russell, Richard; Flynn, Howard; Forth, Scott; Greene, Nathanael; Kezian, Michael; Varanauski, Don; Yoder, Tommy; Woodworth, Warren

2009-01-01

One of the major concerns for the aging Space Shuttle fleet is the stress rupture life of composite overwrapped pressure vessels (COPVs). Stress rupture life of a COPV has been defined as the minimum time during which the composite maintains structural integrity considering the combined effects of stress levels and time. To assist in the evaluation of the aging COPVs in the Orbiter fleet an analytical reliability model was developed. The actual data used to construct this model was from testing of COPVs constructed of similar, but not exactly same materials and pressure cycles as used on Orbiter vessels. Since no actual Orbiter COPV stress rupture data exists the Space Shuttle Program decided to run a stress rupture test to compare to model predictions. Due to availability of spares, the testing was unfortunately limited to one 40" vessel. The stress rupture test was performed at maximum operating pressure at an elevated temperature to accelerate aging. The test was performed in two phases. The first phase, 130 F, a moderately accelerated test designed to achieve the midpoint of the model predicted point reliability. The more aggressive second phase, performed at 160 F was designed to determine if the test article will exceed the 95% confidence interval of the model. This paper will discuss the results of this test, it's implications and possible follow-on testing.

Graphene Membranes for Atmospheric Pressure Photoelectron Spectroscopy.

PubMed

Weatherup, Robert S; Eren, Baran; Hao, Yibo; Bluhm, Hendrik; Salmeron, Miquel B

2016-05-05

Atmospheric pressure X-ray photoelectron spectroscopy (XPS) is demonstrated using single-layer graphene membranes as photoelectron-transparent barriers that sustain pressure differences in excess of 6 orders of magnitude. The graphene serves as a support for catalyst nanoparticles under atmospheric pressure reaction conditions (up to 1.5 bar), where XPS allows the oxidation state of Cu nanoparticles and gas phase species to be simultaneously probed. We thereby observe that the Cu(2+) oxidation state is stable in O2 (1 bar) but is spontaneously reduced under vacuum. We further demonstrate the detection of various gas-phase species (Ar, CO, CO2, N2, O2) in the pressure range 10-1500 mbar including species with low photoionization cross sections (He, H2). Pressure-dependent changes in the apparent binding energies of gas-phase species are observed, attributable to changes in work function of the metal-coated grids supporting the graphene. We expect atmospheric pressure XPS based on this graphene membrane approach to be a valuable tool for studying nanoparticle catalysis.

Does the presence of barred owls suppress the calling behavior of spotted owls?

Treesearch

M.L. Crozier; M.E. Seamans; R.J. Gutierrez; P.J. Loschl; R.B. Horn; S.G. Sovern; E.D. Forsman

2006-01-01

Barred Owls (Strix varia) have expanded their range throughout the ranges of northern (Strix occidentalis caurina) and California spotted owls (S. o. occidentalis). Field observations have suggested that barred owls may be behaviorally dominant to spotted owls. Therefore, we conducted a test of behavioral...

Ultrasonic sludge pretreatment under pressure.

PubMed

Le, Ngoc Tuan; Julcour-Lebigue, Carine; Delmas, Henri

2013-09-01

The objective of this work was to optimize the ultrasound (US) pretreatment of sludge. Three types of sewage sludge were examined: mixed, secondary and secondary after partial methanisation ("digested" sludge). Thereby, several main process parameters were varied separately or simultaneously: stirrer speed, total solid content of sludge (TS), thermal operating conditions (adiabatic vs. isothermal), ultrasonic power input (PUS), specific energy input (ES), and for the first time external pressure. This parametric study was mainly performed for the mixed sludge. Five different TS concentrations of sludge (12-36 g/L) were tested for different values of ES (7000-75,000 kJ/kgTS) and 28 g/L was found as the optimum value according to the solubilized chemical oxygen demand in the liquid phase (SCOD). PUS of 75-150 W was investigated under controlled temperature and the "high power input - short duration" procedure was the most effective at a given ES. The temperature increase in adiabatic US application significantly improved SCOD compared to isothermal conditions. With PUS of 150 W, the effect of external pressure was investigated in the range of 1-16 bar under isothermal and adiabatic conditions for two types of sludge: an optimum pressure of about 2 bar was found regardless of temperature conditions and ES values. Under isothermal conditions, the resulting improvement of sludge disintegration efficacy as compared to atmospheric pressure was by 22-67% and 26-37% for mixed and secondary sludge, respectively. Besides, mean particle diameter (D[4,3]) of the three sludge types decreased respectively from 408, 117, and 110 μm to about 94-97, 37-42, and 36-40 μm regardless of sonication conditions, and the size reduction process was much faster than COD extraction. Copyright © 2013 Elsevier B.V. All rights reserved.

DD-bar production and their interactions

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

Liu Yanrui; Oka, Makoto; Takizawa, Makoto

2011-05-23

We have explored the bound state problem and the scattering problem of the DD-bar pair in a meson exchange model. When considering their production in the e{sup +}e{sup -} process, we included the DD-bar rescattering effect. Although it is difficult to answer whether the S-wave DD-bar bound state exists or not from the binding energies and the phase shifts, one may get an upper limit of the binding energy from the production of the BB-bar, the bottom analog of DD-bar.

IMAGE Project: Results of Laboratory Tests on Tracers for Supercritical Conditions.

NASA Astrophysics Data System (ADS)

Brandvoll, Øyvind; Opsahl Viig, Sissel; Nardini, Isabella; Muller, Jiri

2016-04-01

The use of tracers is a well-established technique for monitoring dynamic behaviour of water and gas through a reservoir. In geothermal reservoirs special challenges are encountered due to high temperatures and pressures. In this work, tracer candidates for monitoring water at supercritical conditions (temperature > 374°C, pressure ca 218 bar), are tested in laboratory experiments. Testing of tracers at supercritical water conditions requires experimental set-ups which tolerate harsh conditions with respect to high temperature and pressure. In addition stringent HES (health, environment and safety) factors have to be taken into consideration when designing and performing the experiments. The setup constructed in this project consists of a pressure vessel, high pressure pump, instrumentation for pressure and temperature control and instrumentation required for accurate sampling of tracers. In order to achieve accurate results, a special focus has been paid to the development of the tracer sampling technique. Perfluorinated cyclic hydrocarbons (PFCs) have been selected as tracer candidates. This group of compounds is today commonly used as gas tracers in oil reservoirs. According to the literature they are stable at temperatures up to 400°C. To start with, five PFCs have been tested for thermal stability in static experiments at 375°C and 108 bar in the experimental setup described above. The tracer candidates will be further tested for several months at the relevant conditions. Preliminary results indicate that some of the PFC compounds show stability after three months. However, in order to arrive at conclusive results, the experiments have to be repeated over a longer period and paying special attention to more accurate sampling procedures.

Edwards nXDS15iC Vacuum Scroll Pump Pressure Testing

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

Sessions, H.; Morgan, G. A.

2013-07-17

The SRNL High Pressure Laboratory performed testing on an Edwards Model nXDS15iC Vacuum Scroll Pump on July 10th and 11th of 2013 at 723-A. This testing was done in an attempt to obtain initial compression ratio information for the nXDS15iC pump, with compression ratio defined as discharge pressure of the pump divided by suction pressure. Pressure burst testing was also done on the pump to determine its design pressure for pressure safety reasons. The Edwards nXDS15iC pump is being evaluated by SRNL for use part of the SHINE project being executed by SRNL.

Nuss bar migrations: occurrence and classification.

PubMed

Binkovitz, Lauren E; Zendejas, Benjamin; Moir, Christopher R; Binkovitz, Larry A

2016-12-01

Pectus excavatum results from dorsal deviation of the sternum causing narrowing of the anterior-posterior diameter of the chest. It can result in significant cosmetic deformities and cardiopulmonary compromise if severe. The Nuss procedure is a minimally invasive technique that involves placing a thin horizontally oriented metal bar below the dorsal sternal apex for correction of the pectus deformity. To identify the frequency and types of Nuss bar migrations, to present a new categorization of bar migrations, and to present examples of true migrations and pseudomigrations. We retrospectively reviewed the electronic medical records and all pertinent radiologic studies of 311 pediatric patients who underwent a Nuss procedure. We evaluated the frequency and type of bar migrations. Bar migration was demonstrated in 23 of 311 patients (7%) and occurred within a mean period of 26 days after surgery. Bar migrations were subjectively defined as deviation of the bar from the position demonstrated on the immediate postoperative radiographs and categorized as superior, inferior, rotation, lateral or flipped using a new classification system. Sixteen of the 23 migrations required re-operation. Nuss bar migration can be diagnosed with careful evaluation of serial radiographs. Nuss bar migration has a wide variety of appearances and requires exclusion of pseudomigration resulting from changes in patient positioning between radiologic examinations.

Effects of a soybean nutrition bar on the postprandial blood glucose and lipid levels in patients with diabetes mellitus.

PubMed

Urita, Yoshihisa; Noda, Tsuneyuki; Watanabe, Daisuke; Iwashita, Soh; Hamada, Koichiro; Sugimoto, Motonobu

2012-12-01

We investigated the influence of a soybean nutrition bar made from whole soy powder on the blood glucose, insulin and lipid levels in comparison with a test cookie with the same amount of energy in patients with diabetes mellitus. In the cross-over designed study, meal tolerance tests using the soybean nutrition bar and test cookie were performed. Two kinds of test meals were used: Study 1 80 kcal, Study 2 592 kcal. The blood glucose response was significantly lower in the soybean nutrition bar trial than in the cookie trial (Studies 1 and 2, p < 0.001). The blood insulin response was also significantly lower in the soybean nutrition bar trial than in the cookie trial (Study 2, p < 0.001). The blood triglyceride and non-esterified fatty acid responses were not significantly different between the two trials, nor were the changes in breath H₂ enrichment (Study 2). The soybean nutrition bar did not induce postprandial hyperglycaemia in diabetic patients unlike the isoenergetic test cookies.

Advantages of the experimental animal hollow organ mechanical testing system for the rat colon rupture pressure test.

PubMed

Ji, Chengdong; Guo, Xuan; Li, Zhen; Qian, Shuwen; Zheng, Feng; Qin, Haiqing

2013-01-01

Many studies have been conducted on colorectal anastomotic leakage to reduce the incidence of anastomotic leakage. However, how to precisely determine if the bowel can withstand the pressure of a colorectal anastomosis experiment, which is called anastomotic bursting pressure, has not been determined. A task force developed the experimental animal hollow organ mechanical testing system to provide precise measurement of the maximum pressure that an anastomotic colon can withstand, and to compare it with the commonly used method such as the mercury and air bag pressure manometer in a rat colon rupture pressure test. Forty-five male Sprague-Dawley rats were randomly divided into the manual ball manometry (H) group, the tracing machine manometry pressure gauge head (MP) group, and the experimental animal hollow organ mechanical testing system (ME) group. The rats in each group were subjected to a cut colon rupture pressure test after injecting anesthesia in the tail vein. Colonic end-to-end anastomosis was performed, and the rats were rested for 1 week before anastomotic bursting pressure was determined by one of the three methods. No differences were observed between the normal colon rupture pressure and colonic anastomotic bursting pressure, which were determined using the three manometry methods. However, several advantages, such as reduction in errors, were identified in the ME group. Different types of manometry methods can be applied to the normal rat colon, but the colonic anastomotic bursting pressure test using the experimental animal hollow organ mechanical testing system is superior to traditional methods. Copyright © 2013 Surgical Associates Ltd. Published by Elsevier Ltd. All rights reserved.

CO2 exposure at pressure impacts metabolism and stress responses in the model sulfate-reducing bacterium Desulfovibrio vulgaris strain Hildenborough

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

Wilkins, Michael J.; Hoyt, David W.; Marshall, Matthew J.

Geologic carbon dioxide (CO2) sequestration drives physical and geochemical changes in deep subsurface environments that impact indigenous microbial activities. The combined effects of pressurized CO2 on a model sulfate-reducing microorganism, Desulfovibrio vulgaris, have been assessed using a suite of genomic and kinetic measurements. Novel high-pressure NMR time-series measurements using 13C-lactate were used to track D. vulgaris metabolism. We identified cessation of respiration at CO2 pressures of 10 bar, 25 bar, 50 bar, and 80 bar. Concurrent experiments using N2 as the pressurizing phase had no negative effect on microbial respiration, as inferred from reduction of sulfate to sulfide. Complementary pressurizedmore » batch incubations and fluorescence microscopy measurements supported NMR observations, and indicated that non-respiring cells were mostly viable at 50 bar CO2 for at least four hours, and at 80 bar CO2 for two hours. The fraction of dead cells increased rapidly after four hours at 80 bar CO2. Transcriptomic (RNA-Seq) measurements on mRNA transcripts from CO2-incubated biomass indicated that cells up-regulated the production of certain amino acids (leucine, isoleucine) following CO2 exposure at elevated pressures, likely as part of a general stress response. Evidence for other poorly understood stress responses were also identified within RNA-Seq data, suggesting that while pressurized CO2 severely limits the growth and respiration of D. vulgaris cells, biomass retains intact cell membranes at pressures up to 80 bar CO2. Together, these data show that geologic sequestration of CO2 may have significant impacts on rates of sulfate reduction in many deep subsurface environments where this metabolism is a key respiratory process.« less

Application of smart BFRP bars with distributed fiber optic sensors into concrete structures

NASA Astrophysics Data System (ADS)

Tang, Yongsheng; Wu, Zhishen; Yang, Caiqian; Wu, Gang; Zhao, Lihua; Song, Shiwei

2010-04-01

In this paper, the self-sensing and mechanical properties of concrete structures strengthened with a novel type of smart basalt fiber reinforced polymer (BFRP) bars were experimentally studied, wherein the sensing element is Brillouin scattering-based distributed optical fiber sensing technique. First, one of the smart bars was applied to strengthen a 2m concrete beam under a 4-points static loading manner in the laboratory. During the experiment, the bar can measure the inner strain changes and monitor the randomly distributed cracks well. With the distributed strain information along the bar, the distributed deformation of the beam can be calculated, and the structural health can be monitored and evaluated as well. Then, two smart bars with a length of about 70m were embedded into a concrete airfield pavement reinforced by long BFRP bars. In the field test, all the optical fiber sensors in the smart bars survived the whole concrete casting process and worked well. From the measured data, the concrete cracks along the pavement length can be easily monitored. The experimental results also confirmed that the bars can strengthen the structures especially after the yielding of steel bars. All the results confirm that this new type of smart BFRP bars show not only good sensing performance but also mechanical performance in the concrete structures.

Effects of pressure on aqueous chemical equilibria at subzero temperatures with applications to Europa

USGS Publications Warehouse

Marion, G.M.; Kargel, J.S.; Catling, D.C.; Jakubowski, S.D.

2005-01-01

Pressure plays a critical role in controlling aqueous geochemical processes in deep oceans and deep ice. The putative ocean of Europa could have pressures of 1200 bars or higher on the seafloor, a pressure not dissimilar to the deepest ocean basin on Earth (the Mariana Trench at 1100 bars of pressure). At such high pressures, chemical thermodynamic relations need to explicitly consider pressure. A number of papers have addressed the role of pressure on equilibrium constants, activity coefficients, and the activity of water. None of these models deal, however, with processes at subzero temperatures, which may be important in cold environments on Earth and other planetary bodies. The objectives of this work were to (1) incorporate a pressure dependence into an existing geochemical model parameterized for subzero temperatures (FREZCHEM), (2) validate the model, and (3) simulate pressure-dependent processes on Europa. As part of objective 1, we examined two models for quantifying the volumetric properties of liquid water at subzero temperatures: one model is based on the measured properties of supercooled water, and the other model is based on the properties of liquid water in equilibrium with ice. The relative effect of pressure on solution properties falls in the order: equilibrium constants(K) > activity coefficients (??) > activity of water (aw). The errors (%) in our model associated with these properties, however, fall in the order: ?? > K > aw. The transposition between K and ?? is due to a more accurate model for estimating K than for estimating ??. Only activity coefficients are likely to be significantly in error. However, even in this case, the errors are likely to be only in the range of 2 to 5% up to 1000 bars of pressure. Evidence based on the pressure/temperature melting of ice and salt solution densities argue in favor of the equilibrium water model, which depends on extrapolations, for characterizing the properties of liquid water in electrolyte

Interaction between a Mg17Al12 precipitate and { 10\\bar 12} < 10\\bar 12 > twin boundary in magnesium alloys

NASA Astrophysics Data System (ADS)

Li, B.; Mathaudhu, S. N.

Interactions between Mg17Al12 precipitates and { 10\\bar 12} < 10\\bar 1\\bar 1 > twin boundaries (TBs) in magnesium were studied by molecular dynamics simulations. The results obtained agree well with experimental observations in which precipitates can be entirely engulfed by { 10\\bar 12} < 10\\bar 1\\bar 1 > twins without being sheared. Structural analysis of the TBs in the atomic scale shows that the TBs are extremely incoherent during twin growth and highly deviate from the { 10\\bar 12} twinning plane as previously observed in a number of experiments. The simulation studies indicate that { 10\\bar 12} < 10\\bar 1\\bar 1 > twinning was accomplished solely by atomic shuffling that converts the parent lattice to the twin lattice without involving twinning dislocations, resulting in zero shear strain at the TBs.

Dark chocolate and blood pressure: a novel study from Jordan.

PubMed

Al-Safi, Saafan A; Ayoub, Nehad M; Al-Doghim, Imad; Aboul-Enein, Faisal H

2011-11-01

The goal of this study was to assess the effect of dark chocolate intake on cardiovascular parameters like blood pressure and heart rate values in a normotensive population. This is a randomized cross-sectional study involving a total of 14,310 adults that were selected from various regions of Jordan. Well-trained pharmacy students interviewed participants in the outpatient settings. Participants reported their weekly intake of dark chocolate that has been further classified into mild (1-2 bars/week), moderate (3-4 bars/week), and high intake ( > 4 bars/week). For each participant, the systolic blood pressure (SBP), diastolic blood pressure (DBP), and heart rate were measured three times with (10-15) minute intervals in the sitting position and the resting state. The arterial blood pressure (ABP) was calculated from the measured SBP and DBP values. All measured blood pressure values were significantly decreased for participants who reported higher dark chocolate consumption. Our results showed that heart rate values were not affected by variable intake of dark chocolate. In addition, increasing dark chocolate intake was associated with a significant decrease of blood pressure values in participants irrespective of the family history of hypertension or the age of the individual. However, heart rate values were unaffected. Higher intake of dark chocolate can be associated with lower values of blood pressure, while its effect on heart rate values was not consistent.

49 CFR 178.345-13 - Pressure and leakage tests.

Code of Federal Regulations, 2014 CFR

2014-10-01

... entire cargo tank surface is inspected for leakage and other sign of defects. The inspection method must... Specifications for Containers for Motor Vehicle Transportation § 178.345-13 Pressure and leakage tests. (a) Each cargo tank must be pressure and leakage tested in accordance with this section and §§ 178.346-5, 178.347...

49 CFR 178.345-13 - Pressure and leakage tests.

Code of Federal Regulations, 2012 CFR

2012-10-01

... entire cargo tank surface is inspected for leakage and other sign of defects. The inspection method must... Specifications for Containers for Motor Vehicle Transportation § 178.345-13 Pressure and leakage tests. (a) Each cargo tank must be pressure and leakage tested in accordance with this section and §§ 178.346-5, 178.347...

49 CFR 178.345-13 - Pressure and leakage tests.

Code of Federal Regulations, 2013 CFR

2013-10-01

... entire cargo tank surface is inspected for leakage and other sign of defects. The inspection method must... Specifications for Containers for Motor Vehicle Transportation § 178.345-13 Pressure and leakage tests. (a) Each cargo tank must be pressure and leakage tested in accordance with this section and §§ 178.346-5, 178.347...

49 CFR 178.345-13 - Pressure and leakage tests.

Code of Federal Regulations, 2011 CFR

2011-10-01

... entire cargo tank surface is inspected for leakage and other sign of defects. The inspection method must... Specifications for Containers for Motor Vehicle Transportation § 178.345-13 Pressure and leakage tests. (a) Each cargo tank must be pressure and leakage tested in accordance with this section and §§ 178.346-5, 178.347...

Eddy current testing of composite pressure vessels

NASA Astrophysics Data System (ADS)

Casperson, R.; Pohl, R.; Munzke, D.; Becker, B.; Pelkner, M.

2018-04-01

The use of composite pressure vessels instead of conventional vessels made of steel or aluminum grew strongly over the last decade. The reason for this trend is the tremendous weight saving in the case of composite vessels. However, the long-time behavior is not fully understood for filling and discharging cycles and creep strength and their influence on the CFRP coating (carbon fiber reinforced plastics) and the internal liner (steel, aluminum, or plastics). The CFRP ensures the pressure resistance while the inner liner is used as a container for liquid or gas. To overcome the missing knowledge of aging, BAM started an internal project to investigate degradation of these material systems. Therefore, applicable testing methods like eddy current testing are needed. Normally, high-frequency eddy current testing (HF-ET, f > 10 MHz) is deployed for CFRP due to its low conductivity of the fiber, which is in the order of 0.01 MS/s, and the capacitive coupling between the fibers. Nevertheless, in some cases conventional ET can be applied. We show a concise summary of studies on the application of conventional ET of composite pressure vessels.

Too Much Bar and Not Enough Mitzvah? A Proposed Research Agenda on Bar/Bat Mitzvah

ERIC Educational Resources Information Center

Schoenfeld, Stuart

2010-01-01

Jewish educators are understandably interested in research on how bar/bat mitzvah affect Jewish education or research on what Jewish schools have done to avoid the distortions of a focus on bar/bat mitzvah. Research might also focus on the somewhat different and more ambitious topic of the role that bar/bat mitzvah play in contemporary Jewish…

The PLVCR 500 and HCPC, tests and results

NASA Astrophysics Data System (ADS)

Leuchsner, Volker

1991-09-01

Developments of volumetric receivers during the last decade which have pointed out the advantages and the wide range of applications in comparison with tube receivers are reported. During three test periods in 1990 the 500 kW version of the Pressure Loaded Volumetric Ceramic Receiver (PLVCR 500) and the Hexagonal Compound Parabolic Concentrator (HCPC) were mounted on the Small Solar Power System (SSPS) tower. Concerning the size of the experiment, it represents the most extensive research and development work on pressure loaded volumetric receivers until now. The receiver and the secondary concentrator were tested together and separately. A gauge pressure of 4.2 bars at air outlet temperatures of 960 C was reached. The secondary concentrator was tested under various flux conditions, the inlet and outlet flux distributions were measured. With this test the feasibility of a modular design of receiver and secondary concentrator could be shown.

A calibration loop to test hot-wire response under supercritical conditions

NASA Astrophysics Data System (ADS)

Radulović, Ivana; Vukoslavčević, P. V.; Wallace, J. M.

2004-11-01

A calibration facility to test the response of hot-wires in CO2 flow under supercritical conditions has been designed and constructed. It is capable of inducing variable speeds at different temperatures and pressures in the ranges of 0.15 - 2 m/s, 15 - 70 deg. C and 1 - 100 bar. The facility is designed as a closed loop with a test section, pump, electrical heater, DC motor and different regulating and measuring devices. The test section is a small tunnel, with a diffuser, honeycomb, screens and a nozzle to provide a uniform flow with a low turbulence level. The speed variation is created by a sealed, magnetic driven gear pump, with a variable rpm DC motor. Using the electrical heater and regulating the amount of CO2 in the facility, the desired temperature and pressure can be reached. The dimensions of the instalation are minimized to reduce the heat, pump power required, and CO2 consumption and to optimize safety. Preliminary testing of a single hot-wire velocity sensor at constant pressure (80 bar) and variable speed and temperature will be briefly described. The hot-wire probes calibrated in this loop will be used to measure turbulence properties in supercritical CO2 in support of improved designs of nuclear reactors to be cooled by supercritical fluids.

Thin film oxygen partial pressure sensor

NASA Technical Reports Server (NTRS)

Wortman, J. J.; Harrison, J. W.; Honbarrier, H. L.; Yen, J.

1972-01-01

The development is described of a laboratory model oxygen partial pressure sensor using a sputtered zinc oxide thin film. The film is operated at about 400 C through the use of a miniature silicon bar. Because of the unique resistance versus temperature relation of the silicon bar, control of the operational temperature is achieved by controlling the resistance. A circuit for accomplishing this is described. The response of sputtered zinc oxide films of various thicknesses to oxygen, nitrogen, argon, carbon dioxide, and water vapor caused a change in the film resistance. Over a large range, film conductance varied approximately as the square root of the oxygen partial pressure. The presence of water vapor in the gas stream caused a shift in the film conductance at a given oxygen partial pressure. A theoretical model is presented to explain the characteristic features of the zinc oxide response to oxygen.

A pressure-packer system for conducting rising head tests in water table wells

USGS Publications Warehouse

Levy, Benjamin S.; Pannell, Lawrence J.; Dadoly, John P.

1993-01-01

The pressure system developed for fully-saturated well screens has been modified for conducting rising head tests in water table wells installed in highly permeable aquifers. The pressure system consists of a compressed air source and 1 inch diameter PVC piping with a packer attached at the end. The pressure system was evaluated in a series of rising head tests conducted in a well at a Superfund site in New England. The well was tested with slugs and with the pressure system. Within each technique, estimates of hydraulic conductivity showed no difference. Comparison of hydraulic conductivity estimates between techniques (slug test vs. pressure test) showed differences due to stratigraphy. The interval tested using slug tests crossed two stratigraphic units; the pressure system tested only one of these units. We conclude that the pressure system may be used to characterize the vertical hydraulic conductivity distribution in a series of successive tests by changing the packer position and the screened interval tested.

The influence of intraocular pressure and air jet pressure on corneal contactless tonometry tests.

PubMed

Simonini, Irene; Pandolfi, Anna

2016-05-01

The air puff is a dynamic contactless tonometer test used in ophthalmology clinical practice to assess the biomechanical properties of the human cornea and the intraocular pressure due to the filling fluids of the eye. The test is controversial, since the dynamic response of the cornea is governed by the interaction of several factors which cannot be discerned within a single measurement. In this study we describe a numerical model of the air puff tests, and perform a parametric analysis on the major action parameters (jet pressure and intraocular pressure) to assess their relevance on the mechanical response of a patient-specific cornea. The particular cornea considered here has been treated with laser reprofiling to correct myopia, and the parametric study has been conducted on both the preoperative and postoperative geometries. The material properties of the cornea have been obtained by means of an identification procedure that compares the static biomechanical response of preoperative and postoperative corneas under the physiological IOP. The parametric study on the intraocular pressure suggests that the displacement of the cornea׳s apex can be a reliable indicator for tonometry, and the one on the air jet pressure predicts the outcomes of two or more distinct measurements on the same cornea, which can be used in inverse procedures to estimate the material properties of the tissue. Copyright © 2015 Elsevier Ltd. All rights reserved.

Wind-Tunnel Tests of Seven Static-Pressure Probes at Transonic Speeds

NASA Technical Reports Server (NTRS)

Capone, Francis J.

1961-01-01

Wind-tunnel tests have been conducted to determine the errors of 3 seven static-pressure probes mounted very close to the nose of a body of revolution simulating a missile forebody. The tests were conducted at Mach numbers from 0.80 to 1.08 and at angles of attack from -1.7 deg to 8.4 deg. The test Reynolds number per foot varied from 3.35 x 10(exp 6) to 4.05 x 10(exp 6). For three 4-vane, gimbaled probes, the static-pressure errors remained constant throughout the test angle-of-attack range for all Mach numbers except 1.02. For two single-vane, self-rotating probes having two orifices at +/-37.5 deg. from the plane of symmetry on the lower surface of the probe body, the static-pressure error varied as much as 1.5 percent of free-stream static pressure through the test angle-of- attack range for all Mach numbers. For two fixed, cone-cylinder probes of short length and large diameter, the static-pressure error varied over the test angle-of-attack range at constant Mach numbers as much as 8 to 10 percent of free-stream static pressure.

Interaction of real and virtual p p bar pairs in J / ψ → p p bar γ (ρ , ω) decays

NASA Astrophysics Data System (ADS)

Milstein, A. I.; Salnikov, S. G.

2017-10-01

The p p bar invariant mass spectra of the processes J / ψ → p p bar ω, J / ψ → p p bar ρ, and J / ψ → p p bar γ close to the p p bar threshold are calculated by means of the N N bar optical potential. The potential model for N N bar interaction in the S10 state is proposed. The parameters of the model are obtained by fitting the cross section of N N bar scattering together with the p p bar invariant mass spectra of the J / ψ decays. Good agreement with the available experimental data is achieved. Using our potential and the Green's function approach we also describe the peak in the η‧π+π- invariant mass spectrum in the decay J / ψ → γη‧π+π- in the energy region near the N N bar threshold.

Glass Fiber Reinforced Polymer Dowel Bar Evaluation

DOT National Transportation Integrated Search

2012-09-01

Glass Fiber Reinforced Polymer (GFRP) dowel bars were installed on one new construction project and two dowel bar : retrofit projects to evaluate the performance of this type of dowel bar in comparison to steel dowel bars installed on the same : cont...

Evaluation of Acoustic Emission SHM of PRSEUS Composite Pressure Cube Tests

NASA Technical Reports Server (NTRS)

Horne, Michael R.; Madaras, Eric I.

2013-01-01

A series of tests of the Pultruded Rod Stitched Efficient Unitized Structure (PRSEUS) pressure cube were conducted during third quarter 2011 at NASA Langley Research Center (LaRC) in the Combined Loads Test facility (COLTS). This is a report of the analysis of the Acoustic Emission (AE) data collected during those tests. The AE signals of the later tests are consistent with the final failure progression through two of the pressure cube panels. Calibration tests and damage precursor AE indications, from preliminary checkout pressurizations, indicated areas of concern that eventually failed. Hence those tests have potential for vehicle health monitoring.

Minimally Invasive Repair of Pectus Excavatum Without Bar Stabilizers Using Endo Close.

PubMed

Pio, Luca; Carlucci, Marcello; Leonelli, Lorenzo; Erminio, Giovanni; Mattioli, Girolamo; Torre, Michele

2016-02-01

Since the introduction of the Nuss technique for pectus excavatum (PE) repair, stabilization of the bar has been a matter of debate and a crucial point for the outcome, as bar dislocation remains one of the most frequent complications. Several techniques have been described, most of them including the use of a metal stabilizer, which, however, can increase morbidity and be difficult to remove. Our study compares bar stabilization techniques in two groups of patients, respectively, with and without the metal stabilizer. A retrospective study on patients affected by PE and treated by the Nuss technique from January 2012 to June 2013 at our institution was performed in order to evaluate the efficacy of metal stabilizers. Group 1 included patients who did not have the metal stabilizer inserted; stabilization was achieved with multiple (at least four) bilateral pericostal Endo Close™ (Auto Suture, US Surgical; Tyco Healthcare Group, Norwalk, CT) sutures. Group 2 included patients who had a metal stabilizer placed because pericostal sutures could not be used bilaterally. We compared the two groups in terms of bar dislocation rate, surgical operative time, and other complications. Statistical analysis was performed with the Mann-Whitney U test and Fisher's exact test. Fifty-seven patients were included in the study: 37 in Group 1 and 20 in Group 2. Two patients from Group 2 had a bar dislocation. Statistical analysis showed no difference between the two groups in dislocation rate or other complications. In our experience, the placement of a metal stabilizer did not reduce the rate of bar dislocation. Bar stabilization by the pericostal Endo Close suture technique appears to have no increase in morbidity or migration compared with the metal lateral stabilizer technique.

Mechanical splicing of superelastic Cu–Al–Mn alloy bars with headed ends

NASA Astrophysics Data System (ADS)

Kise, S.; Mohebbi, A.; Saiidi, M. S.; Omori, T.; Kainuma, R.; Shrestha, K. C.; Araki, Y.

2018-06-01

This paper examines the feasibility of mechanical splicing using a steel coupler to connect headed ends of superelastic Cu–Al–Mn alloy (Camalloy) bars and steel reinforcing bars to be used in concrete structures. Although threading of Camalloy is as easy as that of steel, mechanical splicing using threaded ends requires machining of Camalloy bars into dog-bone shape to avoid brittle fracture at the threaded ends. The machining process requires significant time and cost and wastes substantial amount of the material. This paper attempts to resolve this issue by applying mechanical splicing using steel couplers to connect headed ends of Camalloy and steel reinforcing bars. To study its feasibility, we prepare 3 specimens wherein both ends of each Camalloy bar (13 mm diameter and 300 mm length) are connected to steel reinforcing bars. The specimens are tested under monotonic, single-cycle, and full-cycle tension loading conditions. From these tests, we observed (1) excellent superelasticity with recoverable strain of around 6% and (2) large ductility with fracture strain of over 19%. It should be emphasized here that, in all the specimens, ductile fracture occurred at the locations apart from the headed ends. This is in sharp contrast with brittle fracture of headed superelastic Ni–Ti SMA bars, most of which took place around the headed ends. From the results of the microstructural analysis, we identified the following reasons for avoiding brittle fracture at the headed ends: (1) Precipitation hardening increases the strength around the boundary between the straight and headed (tapered) portions, where stress concentration takes place. (2) The strength of the straight portion does not increase significantly up to the ductile fracture if its grain orientation is close to 〈0 0 1〉.

49 CFR 179.400-21 - Test of pressure relief valves.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 49 Transportation 3 2013-10-01 2013-10-01 false Test of pressure relief valves. 179.400-21 Section... CARS Specification for Cryogenic Liquid Tank Car Tanks and Seamless Steel Tanks (Classes DOT-113 and 107A) § 179.400-21 Test of pressure relief valves. Each valve must be tested with air or gas for...

49 CFR 179.400-21 - Test of pressure relief valves.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 49 Transportation 2 2010-10-01 2010-10-01 false Test of pressure relief valves. 179.400-21 Section... FOR TANK CARS Specification for Cryogenic Liquid Tank Car Tanks and Seamless Steel Tanks (Classes DOT-113 and 107A) § 179.400-21 Test of pressure relief valves. Each valve must be tested with air or gas...

Evaluation of the concept of pressure proof testing fuselage structures

NASA Technical Reports Server (NTRS)

Harris, Charles E.; Orringer, Oscar

1991-01-01

The FAA and NASA have recently completed independent technical evaluations of the concept of pressure proof testing the fuselage of commercial transport airplanes. The results of these evaluations are summarized. The objectives of the evaluations were to establish the potential benefit of the pressure proof test, to quantify the most desirable proof test pressure, and to quantify the required proof test interval. The focus of the evaluations was on multiple-site cracks extending from adjacent rivet holes of a typical fuselage longitudinal lap splice joint. The FAA and NASA do not support pressure proof testing the fuselage of aging commercial transport aircraft. The argument against proof testing is as follows: (1) a single proof test does not insure an indefinite life; therefore, the proof test must be repeated at regular intervals; (2) for a proof factor of 1.33, the required proof test interval must be below 300 flights to account for uncertainties in the evaluation; (3) conducting the proof test at a proof factor of 1.5 would considerably exceed the fuselage design limit load; therefore, it is not consistent with accepted safe practices; and (4) better safety can be assured by implementing enhanced nondestructive inspection requirements, and adequate reliability can be achieved by an inspection interval several times longer than the proof test interval.

Atmospheric pressure gas chromatography-time-of-flight-mass spectrometry (APGC-ToF-MS) for the determination of regulated and emerging contaminants in aqueous samples after stir bar sorptive extraction (SBSE).

PubMed

Pintado-Herrera, Marina G; González-Mazo, Eduardo; Lara-Martín, Pablo A

2014-12-03

This work presents the development, optimization and validation of a multi-residue method for the simultaneous determination of 102 contaminants, including fragrances, UV filters, repellents, endocrine disruptors, biocides, polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), and several types of pesticides in aqueous matrices. Water samples were processed using stir bar sorptive extraction (SBSE) after the optimization of several parameters: agitation time, ionic strength, presence of organic modifiers, pH, and volume of the derivatizing agent. Target compounds were extracted from the bars by liquid desorption (LD). Separation, identification and quantification of analytes were carried out by gas chromatography (GC) coupled to time-of-flight (ToF-MS) mass spectrometry. A new ionization source, atmospheric pressure gas chromatography (APGC), was tested. The optimized protocol showed acceptable recovery percentages (50-100%) and limits of detection below 1ngL(-1) for most of the compounds. Occurrence of 21 out of 102 analytes was confirmed in several environmental aquatic matrices, including seawater, sewage effluent, river water and groundwater. Non-target compounds such as organophosphorus flame retardants were also identified in real samples by accurate mass measurement of their molecular ions using GC-APGC-ToF-MS. To the best of our knowledge, this is the first time that this technique has been applied for the analysis of contaminants in aquatic systems. By employing lower energy than the more widely used electron impact ionization (EI), AGPC provides significant advantages over EI for those substances very susceptible to high fragmentation (e.g., fragrances, pyrethroids). Copyright © 2014 Elsevier B.V. All rights reserved.

Membrane-Sculpting BAR Domains Generate Stable Lipid Microdomains

PubMed Central

Zhao, Hongxia; Michelot, Alphée; Koskela, Essi V.; Tkach, Vadym; Stamou, Dimitrios; Drubin, David G.; Lappalainen, Pekka

2014-01-01

SUMMARY Bin-Amphiphysin-Rvs (BAR) domain proteins are central regulators of many cellular processes involving membrane dynamics. BAR domains sculpt phosphoinositide-rich membranes to generate membrane protrusions or invaginations. Here, we report that, in addition to regulating membrane geometry, BAR domains can generate extremely stable lipid microdomains by “freezing” phosphoinositide dynamics. This is a general feature of BAR domains, because the yeast endocytic BAR and Fes/CIP4 homology BAR (F-BAR) domains, the inverse BAR domain of Pinkbar, and the eisosomal BAR protein Lsp1 induced phosphoinositide clustering and halted lipid diffusion, despite differences in mechanisms of membrane interactions. Lsp1 displays comparable low diffusion rates in vitro and in vivo, suggesting that BAR domain proteins also generate stable phosphoinositide microdomains in cells. These results uncover a conserved role for BAR superfamily proteins in regulating lipid dynamics within membranes. Stable microdomains induced by BAR domain scaffolds and specific lipids can generate phase boundaries and diffusion barriers, which may have profound impacts on diverse cellular processes. PMID:24055060

Membrane-sculpting BAR domains generate stable lipid microdomains.

PubMed

Zhao, Hongxia; Michelot, Alphée; Koskela, Essi V; Tkach, Vadym; Stamou, Dimitrios; Drubin, David G; Lappalainen, Pekka

2013-09-26

Bin-Amphiphysin-Rvs (BAR) domain proteins are central regulators of many cellular processes involving membrane dynamics. BAR domains sculpt phosphoinositide-rich membranes to generate membrane protrusions or invaginations. Here, we report that, in addition to regulating membrane geometry, BAR domains can generate extremely stable lipid microdomains by "freezing" phosphoinositide dynamics. This is a general feature of BAR domains, because the yeast endocytic BAR and Fes/CIP4 homology BAR (F-BAR) domains, the inverse BAR domain of Pinkbar, and the eisosomal BAR protein Lsp1 induced phosphoinositide clustering and halted lipid diffusion, despite differences in mechanisms of membrane interactions. Lsp1 displays comparable low diffusion rates in vitro and in vivo, suggesting that BAR domain proteins also generate stable phosphoinositide microdomains in cells. These results uncover a conserved role for BAR superfamily proteins in regulating lipid dynamics within membranes. Stable microdomains induced by BAR domain scaffolds and specific lipids can generate phase boundaries and diffusion barriers, which may have profound impacts on diverse cellular processes. Copyright © 2013 The Authors. Published by Elsevier Inc. All rights reserved.

Nutrition systems for pressure suits.

NASA Technical Reports Server (NTRS)

Huber, C. S.; Heidelbaugh, N. D.; Rapp, R. M.; Smith, M. C., Jr.

1973-01-01

Nutrition systems were successfully developed in the Apollo Program for astronauts wearing pressure suits during emergency decompression situations and during lunar surface explorations. These nutrition systems consisted of unique dispensers, water, flavored beverages, nutrient-fortified beverages, and intermediate moisture food bars. The emergency decompression system dispensed the nutrition from outside the pressure suit by interfacing with a suit helmet penetration port. The lunar exploration system utilized dispensers stowed within the interior layers of the pressure suit. These systems could be adapted for provision of nutrients in other situations requiring the use of pressure suits.

Seismic Behavior and Retrofit of Concrete Columns of Old R.C. Buildings Reinforced With Plain Bars

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

Marefat, M. S.; Arani, K. Karbasi; Shirazi, S. M. Hassanzadeh

2008-07-08

Seismic rehabilitation of old buildings has been a major challenge in recent years. The first step in seismic rehabilitation is evaluation of the existing capacity and the seismic behaviour. For investigation of the seismic behaviour of RC members of a real old building in Iran which has been designed and constructed by European engineers in 1940, three half-scale column specimens reinforced with plain bars have been tested. The tests indicate significant differences between the responses of specimens reinforced by plain bars relative to those reinforced by deformed bars. A regular pattern of cracking and a relatively brittle behaviour was observedmore » while a relatively large residual strength appeared after sudden drop of initial strength and stiffness due to slip of longitudinal bars.« less

30 CFR 18.98 - Enclosures, joints, and fastenings; pressure testing.

Code of Federal Regulations, 2013 CFR

2013-07-01

... consistent with unyielding components during a pressure-time history as derived from a series of oscillograms...; pressure testing. (a) Cast or welded enclosures shall be designed to withstand a minimum internal pressure...

30 CFR 18.98 - Enclosures, joints, and fastenings; pressure testing.

Code of Federal Regulations, 2012 CFR

2012-07-01

... consistent with unyielding components during a pressure-time history as derived from a series of oscillograms...; pressure testing. (a) Cast or welded enclosures shall be designed to withstand a minimum internal pressure...

30 CFR 18.98 - Enclosures, joints, and fastenings; pressure testing.

Code of Federal Regulations, 2014 CFR

2014-07-01

... consistent with unyielding components during a pressure-time history as derived from a series of oscillograms...; pressure testing. (a) Cast or welded enclosures shall be designed to withstand a minimum internal pressure...

30 CFR 18.98 - Enclosures, joints, and fastenings; pressure testing.

Code of Federal Regulations, 2010 CFR

2010-07-01

... consistent with unyielding components during a pressure-time history as derived from a series of oscillograms...; pressure testing. (a) Cast or welded enclosures shall be designed to withstand a minimum internal pressure...

30 CFR 18.98 - Enclosures, joints, and fastenings; pressure testing.

Code of Federal Regulations, 2011 CFR

2011-07-01

... consistent with unyielding components during a pressure-time history as derived from a series of oscillograms...; pressure testing. (a) Cast or welded enclosures shall be designed to withstand a minimum internal pressure...

Large velocity dispersion of molecular gas in bars of strongly barred galaxies NGC 1300 and NGC 5383

NASA Astrophysics Data System (ADS)

Maeda, Fumiya; Ohta, Kouji; Fujimoto, Yusuke; Habe, Asao; Baba, Junichi

2018-06-01

We carried out ^{12}CO(J = 1-0) observations toward bar and arm regions of the strongly barred galaxies NGC 1300 and NGC 5383 with the Nobeyama 45 m radio telescope (beam size of 1-2 kpc in the galaxies). The aim of the observations is to qualitatively examine a new scenario for the suppression of star formation in bars based on recent high-resolution numerical simulations: higher speed collisions between molecular clouds in the bar region compared with the arm region suppress the massive star formation. CO emissions were detected from all the regions, indicating the presence of molecular gases in the strong bars without associating clear H II regions. In both galaxies, the velocity width of the CO line profile tends to be larger in the bar region than in the arm region, which is qualitatively consistent with the new scenario.

Numerical modeling of self-pressurization and pressure control by a thermodynamic vent system in a cryogenic tank

NASA Astrophysics Data System (ADS)

Majumdar, Alok; Valenzuela, Juan; LeClair, Andre; Moder, Jeff

2016-03-01

This paper presents a numerical model of a system-level test bed-the multipurpose hydrogen test bed (MHTB) using the Generalized Fluid System Simulation Program (GFSSP). MHTB is representative in size and shape of a space transportation vehicle liquid hydrogen propellant tank, and ground-based testing was performed at NASA Marshall Space Flight Center (MSFC) to generate data for cryogenic storage. GFSSP is a finite volume-based network flow analysis software developed at MSFC and used for thermofluid analysis of propulsion systems. GFSSP has been used to model the self-pressurization and ullage pressure control by the Thermodynamic Vent System (TVS). A TVS typically includes a Joule-Thompson (J-T) expansion device, a two-phase heat exchanger (HEX), and a mixing pump and liquid injector to extract thermal energy from the tank without significant loss of liquid propellant. For the MHTB tank, the HEX and liquid injector are combined into a vertical spray bar assembly. Two GFSSP models (Self-Pressurization and TVS) were separately developed and tested and then integrated to simulate the entire system. The Self-Pressurization model consists of multiple ullage nodes, a propellant node, and solid nodes; it computes the heat transfer through multilayer insulation blankets and calculates heat and mass transfer between the ullage and liquid propellant and the ullage and tank wall. A TVS model calculates the flow through a J-T valve, HEX, and spray and vent systems. Two models are integrated by exchanging data through User Subroutines of both models. Results of the integrated models have been compared with MHTB test data at a 50% fill level. Satisfactory comparison was observed between tests and numerical predictions.

Wind pressure testing of tornado safe room components made from wood

Treesearch

Robert Falk; Deepak Shrestha

2016-01-01

To evaluate the ability of a wood tornado safe room to resist wind pressures produced by a tornado, two safe room com-ponents were tested for wind pressure strength. A tornado safe room ceiling panel and door were static-pressure-tested according to ASTM E 330 using a vacuum test system. Re-sults indicate that the panels had load capacities from 2.4 to 3.5 times that...

Effects of hydrogen partial pressure on autotrophic growth and product formation of Acetobacterium woodii.

PubMed

Kantzow, Christina; Weuster-Botz, Dirk

2016-08-01

Low aqueous solubility of the gases for autotrophic fermentations (e.g., hydrogen gas) results in low productivities in bioreactors. A frequently suggested approach to overcome mass transfer limitation is to increase the solubility of the limiting gas in the reaction medium by increasing the partial pressure in the gas phase. An increased inlet hydrogen partial pressure of up to 2.1 bar (total pressure of 3.5 bar) was applied for the autotrophic conversion of hydrogen and carbon dioxide with Acetobacterium woodii in a batch-operated stirred-tank bioreactor with continuous gas supply. Compared to the autotrophic batch process with an inlet hydrogen partial pressure of 0.4 bar (total pressure of 1.0 bar) the final acetate concentration after 3.1 days was reduced to 50 % (29.2 g L(-1) compared to 59.3 g L(-1)), but the final formate concentration was increased by a factor of 18 (7.3 g L(-1) compared to 0.4 g L(-1)). Applying recombinant A. woodii strains overexpressing either genes for enzymes in the methyl branch of the Wood-Ljungdahl pathway or the genes phosphotransacetylase and acetate kinase at an inlet hydrogen partial pressure of 1.4 bar reduced the final formate concentration by up to 40 % and increased the final dry cell mass and acetate concentrations compared to the wild type strain. Solely the overexpression of the two genes for ATP regeneration at the end of the Wood-Ljungdahl pathway resulted in an initial switch off of formate production at increased hydrogen partial pressure until the maximum of the hydrogen uptake rate was reached.

A Multivariate Generalizability Analysis of the Multistate Bar Examination

ERIC Educational Resources Information Center

Yin, Ping

2005-01-01

The main purpose of this study is to examine the content structure of the Multistate Bar Examination (MBE) using the "table of specifications" model from the perspective of multivariate generalizability theory. Specifically, using MBE data collected over different years (six administrations: three from the February test and three from July test),…

Devices and process for high-pressure magic angle spinning nuclear magnetic resonance

DOEpatents

Hoyt, David W; Sears, Jr., Jesse A; Turcu, Romulus V.F.; Rosso, Kevin M; Hu, Jian Zhi

2014-04-08

A high-pressure magic angle spinning (MAS) rotor is detailed that includes a high-pressure sample cell that maintains high pressures exceeding 150 bar. The sample cell design minimizes pressure losses due to penetration over an extended period of time.

Devices and process for high-pressure magic angle spinning nuclear magnetic resonance

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

Hoyt, David W.; Sears, Jesse A.; Turcu, Romulus V. F.

A high-pressure magic angle spinning (MAS) rotor is detailed that includes a high-pressure sample cell that maintains high pressures exceeding 150 bar. The sample cell design minimizes pressure losses due to penetration over an extended period of time.

Bar Coding and Tracking in Pathology.

PubMed

Hanna, Matthew G; Pantanowitz, Liron

2016-03-01

Bar coding and specimen tracking are intricately linked to pathology workflow and efficiency. In the pathology laboratory, bar coding facilitates many laboratory practices, including specimen tracking, automation, and quality management. Data obtained from bar coding can be used to identify, locate, standardize, and audit specimens to achieve maximal laboratory efficiency and patient safety. Variables that need to be considered when implementing and maintaining a bar coding and tracking system include assets to be labeled, bar code symbologies, hardware, software, workflow, and laboratory and information technology infrastructure as well as interoperability with the laboratory information system. This article addresses these issues, primarily focusing on surgical pathology. Copyright © 2016 Elsevier Inc. All rights reserved.

Bar Coding and Tracking in Pathology.

PubMed

Hanna, Matthew G; Pantanowitz, Liron

2015-06-01

Bar coding and specimen tracking are intricately linked to pathology workflow and efficiency. In the pathology laboratory, bar coding facilitates many laboratory practices, including specimen tracking, automation, and quality management. Data obtained from bar coding can be used to identify, locate, standardize, and audit specimens to achieve maximal laboratory efficiency and patient safety. Variables that need to be considered when implementing and maintaining a bar coding and tracking system include assets to be labeled, bar code symbologies, hardware, software, workflow, and laboratory and information technology infrastructure as well as interoperability with the laboratory information system. This article addresses these issues, primarily focusing on surgical pathology. Copyright © 2015 Elsevier Inc. All rights reserved.

High Pressure Hydrogen Pressure Relief Devices: Accelerated Life Testing and Application Best Practices

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

Burgess, Robert M.; Post, Matthew B.; Buttner, William J.

Pressure relief devices (PRDs ) are used to protect high pressure systems from burst failure caused by overpressurization. Codes and standards require the use of PRDs for the safe design of many pressurized systems. These systems require high reliability due to the risks associated with a burst failure. Hydrogen service can increase the risk of PRD failure due to material property degradation caused by hydrogen attack. The National Renewable Energy Laboratory (NREL) has conducted an accelerated life test on a conventional spring loaded PRD. Based on previous failures in the field, the nozzles specific to these PRDs are of particularmore » interest. A nozzle in a PRD is a small part that directs the flow of fluid toward the sealing surface to maintain the open state of the valve once the spring force is overcome. The nozzle in this specific PRD is subjected to the full tensile force of the fluid pressure. These nozzles are made from 440C material, which is a type of hardened steel that is commonly chosen for high pressure applications because of its high strength properties. In a hydrogen environment, however, 440C is considered a worst case material since hydrogen attack results in a loss of almost all ductility and thus 440C is prone to fatigue and material failure. Accordingly, 440C is not recommended for hydrogen service. Conducting an accelerated life test on a PRD with 440C material provides information on necessary and sufficient conditions required to produce crack initiation and failure. The accelerated life test also provides information on other PRD failure modes that are somewhat statistically random in nature.« less

Why Are Some Galaxies Not Barred?

NASA Astrophysics Data System (ADS)

Saha, Kanak; Elmegreen, Bruce

2018-05-01

Although more than two-thirds of star-forming disk galaxies in the local universe are barred, some galaxies remain unbarred, occupying the upper half of the Hubble tuning fork diagram. Numerical simulations almost always produce bars spontaneously, so it remains a challenge to understand how galaxies sometimes prevent bars from forming. Using a set of collisionless simulations, we first reproduce the common result that cold stellar disks surrounding a classical bulge become strongly unstable to non-axisymmetric perturbations, leading to the rapid formation of spiral structure and bars. However, our analyses show that galaxy models with compact classical bulges (whose average density is greater than or comparable to the disk density calculated within bulge half-mass radii) are able to prevent bar formation for at least 4 Gyr even when the stellar disk is maximal and having low Toomre Q. Such bar prevention is the result of several factors such as (a) a small inner Lindblad resonance with a high angular rate, which contaminates an incipient bar with x 2 orbits, and (b) rapid loss of angular momentum accompanied by a rapid heating in the center from initially strong bar and spiral instabilities in a low-Q disk; in other words, a rapid initial rise to a value larger than ∼5 of the ratio of the random energy to the rotational energy in the central region of the galaxy.

PRSEUS Pressure Cube Test Data and Response

NASA Technical Reports Server (NTRS)

Lovejoy, Andrew E.

2013-01-01

NASA s Environmentally Responsible Aviation (ERA) Program is examining the hybrid wing body (HWB) aircraft, among others, in an effort to increase the fuel efficiency of commercial aircraft. The HWB design combines features of a flying wing with features of conventional transport aircraft, and has the advantage of simultaneously increasing both fuel efficiency and payload. Recent years have seen an increased focus on the structural performance of the HWB. The key structural challenge of a HWB airframe is the ability to create a cost and weight efficient, non-circular, pressurized shell. Conventional round fuselage sections react cabin pressure by hoop tension. However, the structural configuration of the HWB subjects the majority of the structural panels to bi-axial, in-plane loads in addition to the internal cabin pressure, which requires more thorough examination and analysis than conventional transport aircraft components having traditional and less complex load paths. To address this issue, while keeping structural weights low, extensive use of advanced composite materials is made. This report presents the test data and preliminary conclusions for a pressurized cube test article that utilizes Boeing's Pultruded Rod Stitched Efficient Unitized Structure (PRSEUS), and which is part of the building block approach used for HWB development.

Medium- and high-pressure gauges and transducers produced by laser welding technology

NASA Astrophysics Data System (ADS)

Daurelio, Giuseppe; Nenci, Fabio; Cinquepalmi, Massimo; Chita, Giuseppe

1998-07-01

Industrial manufacturers produce many types of pressure gauges and transducers according to the applications, for gas or liquid, for high-medium and low pressure ranges. Nowadays the current production technology generally prefers to weld by micro TIG source the metallic corrugated membranes to the gauge or transducer bodies for the products, operating on the low pressure or medium pressure ranges. For the other ones, operating to high pressure range, generally the two components of the transducers are both threaded only and threaded and then circularly welded by micro TIG for the other higher range, till to 1000 bar. In this work the products, operating on the approximately equals 30 divided by 200 bar, are considered. These, when assembled on industrial plants, as an outcome of a non-correct operating sequence, give a 'shifted' electrical signal. This is due to a shift of the 'zero electrical signal' that unbalances the electrical bridge - thin layer sensor - that is the sensitive part of the product. Moreover, for the same problem, often some mechanical settlings of the transducer happen during the first pressure semi-components, with an increasing of the product manufacturing costs. In light of all this, the above referred, in this work the whole transducer has been re-designed according to the specific laser welding technology requirements. On the new product no threaded parts exist but only a circular laser welding with a full penetration depth about 2.5 divided by 3 mm high. Three different alloys have been tested according to the applications and the mechanical properties requested to the transducer. By using a 1.5 KW CO2 laser system many different working parameters have been evaluated for correlating laser parameters to the penetration depths, crown wides, interaction laser-materia times, mechanical and metallurgical properties. Moreover during the laser welding process the measurements of the maximum temperature, reached by the transducer top, has been

Three-Dimensional Digital Image Correlation of a Composite Overwrapped Pressure Vessel During Hydrostatic Pressure Tests

NASA Technical Reports Server (NTRS)

Revilock, Duane M., Jr.; Thesken, John C.; Schmidt, Timothy E.

2007-01-01

Ambient temperature hydrostatic pressurization tests were conducted on a composite overwrapped pressure vessel (COPV) to understand the fiber stresses in COPV components. Two three-dimensional digital image correlation systems with high speed cameras were used in the evaluation to provide full field displacement and strain data for each pressurization test. A few of the key findings will be discussed including how the principal strains provided better insight into system behavior than traditional gauges, a high localized strain that was measured where gages were not present and the challenges of measuring curved surfaces with the use of a 1.25 in. thick layered polycarbonate panel that protected the cameras.

Non-Axisymmetric Inflatable Pressure Structure (NAIPS) Full-Scale Pressure Test

NASA Technical Reports Server (NTRS)

Jones, Thomas C.; Doggett, William R.; Warren, Jerry E.; Watson, Judith J.; Shariff, Khadijah; Makino, Alberto; Yount, Bryan C.

2017-01-01

Inflatable space structures have the potential to significantly reduce the required launch volume for large pressure vessels required for exploration applications including habitats, airlocks and tankage. In addition, mass savings can be achieved via the use of high specific strength softgoods materials, and the reduced design penalty from launching the structure in a densely packaged state. Large inclusions however, such as hatches, induce a high mass penalty at the interfaces with the softgoods and in the added rigid structure while reducing the packaging efficiency. A novel, Non-Axisymmetric Inflatable Pressure Structure (NAIPS) was designed and recently tested at NASA Langley Research Center to demonstrate an elongated inflatable architecture that could provide areas of low stress along a principal axis in the surface. These low stress zones will allow the integration of a flexible linear seal that substantially reduces the added mass and volume of a heritage rigid hatch structure. This paper describes the test of the first full-scale engineering demonstration unit (EDU) of the NAIPS geometry and a comparison of the results to finite element analysis.

Experimental study of the seismic performance of L-shaped columns with 500 MPa steel bars.

PubMed

Wang, Tiecheng; Liu, Xiao; Zhao, Hailong

2014-01-01

Based on tests on six L-shaped RC columns with 500 MPa steel bars, the effect of axial compression ratios and stirrup spacing on failure mode, bearing capacity, displacement, and curvature ductility of the specimens is investigated. Test results show that specimens with lower axial load and large stirrup characteristic value (larger than about 0.35) are better at ductility and seismic performance, while specimens under high axial load or with a small stirrup characteristic value (less than about 0.35) are poorer at ductility; L-shaped columns with 500 MPa steel bars show better bearing capacity and ductility in comparison with specimens with HRB400 steel bars.

Numerical modeling of the divided bar measurements

NASA Astrophysics Data System (ADS)

LEE, Y.; Keehm, Y.

2011-12-01

relative error in measured thermal conductivity is 4.01%, while the relative error can be very significant (~12.2%) if the thickness increases to 0.1 mm. Then, we fixed the thickness (0.03 mm) and varied thermal conductivity of the thermal compound. We found that the relative error with an 1.0 W/m/K compound is 1.28%, and the relative error with a 0.29 W/m/K is 4.06%. When we repeated this test with a different thickness of the thermal compound (0.1 mm), the relative error with an 1.0 W/m/K compound is 3.93%, and that with a 0.29 W/m/K is 12.2%. In addition, the cell technique by Sass et al.(1971), which is widely used to measure thermal conductivity of rock fragments, was evaluated using the FEM modeling. A total of 483 isotropic and homogeneous spherical rock fragments in the sample holder were used to test numerically the accuracy of the cell technique. The result shows the relative error of -9.61% for rock fragments with the thermal conductivity of 2.5 W/m/K. In conclusion, we report quantified errors in the divided-bar and the cell technique for thermal conductivity measurements for rocks and fragments. We found that the FEM modeling can accurately mimic these measurement techniques and can help us to estimate measurement errors quantitatively.

49 CFR 236.705 - Bar, locking.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 49 Transportation 4 2010-10-01 2010-10-01 false Bar, locking. 236.705 Section 236.705..., MAINTENANCE, AND REPAIR OF SIGNAL AND TRAIN CONTROL SYSTEMS, DEVICES, AND APPLIANCES Definitions § 236.705 Bar, locking. A bar in an interlocking machine to which the locking dogs are attached. ...

Predicting vertical jump height from bar velocity.

PubMed

García-Ramos, Amador; Štirn, Igor; Padial, Paulino; Argüelles-Cienfuegos, Javier; De la Fuente, Blanca; Strojnik, Vojko; Feriche, Belén

2015-06-01

The objective of the study was to assess the use of maximum (Vmax) and final propulsive phase (FPV) bar velocity to predict jump height in the weighted jump squat. FPV was defined as the velocity reached just before bar acceleration was lower than gravity (-9.81 m·s(-2)). Vertical jump height was calculated from the take-off velocity (Vtake-off) provided by a force platform. Thirty swimmers belonging to the National Slovenian swimming team performed a jump squat incremental loading test, lifting 25%, 50%, 75% and 100% of body weight in a Smith machine. Jump performance was simultaneously monitored using an AMTI portable force platform and a linear velocity transducer attached to the barbell. Simple linear regression was used to estimate jump height from the Vmax and FPV recorded by the linear velocity transducer. Vmax (y = 16.577x - 16.384) was able to explain 93% of jump height variance with a standard error of the estimate of 1.47 cm. FPV (y = 12.828x - 6.504) was able to explain 91% of jump height variance with a standard error of the estimate of 1.66 cm. Despite that both variables resulted to be good predictors, heteroscedasticity in the differences between FPV and Vtake-off was observed (r(2) = 0.307), while the differences between Vmax and Vtake-off were homogenously distributed (r(2) = 0.071). These results suggest that Vmax is a valid tool for estimating vertical jump height in a loaded jump squat test performed in a Smith machine. Key pointsVertical jump height in the loaded jump squat can be estimated with acceptable precision from the maximum bar velocity recorded by a linear velocity transducer.The relationship between the point at which bar acceleration is less than -9.81 m·s(-2) and the real take-off is affected by the velocity of movement.Mean propulsive velocity recorded by a linear velocity transducer does not appear to be optimal to monitor ballistic exercise performance.

Predicting Vertical Jump Height from Bar Velocity

PubMed Central

García-Ramos, Amador; Štirn, Igor; Padial, Paulino; Argüelles-Cienfuegos, Javier; De la Fuente, Blanca; Strojnik, Vojko; Feriche, Belén

2015-01-01

The objective of the study was to assess the use of maximum (Vmax) and final propulsive phase (FPV) bar velocity to predict jump height in the weighted jump squat. FPV was defined as the velocity reached just before bar acceleration was lower than gravity (-9.81 m·s-2). Vertical jump height was calculated from the take-off velocity (Vtake-off) provided by a force platform. Thirty swimmers belonging to the National Slovenian swimming team performed a jump squat incremental loading test, lifting 25%, 50%, 75% and 100% of body weight in a Smith machine. Jump performance was simultaneously monitored using an AMTI portable force platform and a linear velocity transducer attached to the barbell. Simple linear regression was used to estimate jump height from the Vmax and FPV recorded by the linear velocity transducer. Vmax (y = 16.577x - 16.384) was able to explain 93% of jump height variance with a standard error of the estimate of 1.47 cm. FPV (y = 12.828x - 6.504) was able to explain 91% of jump height variance with a standard error of the estimate of 1.66 cm. Despite that both variables resulted to be good predictors, heteroscedasticity in the differences between FPV and Vtake-off was observed (r2 = 0.307), while the differences between Vmax and Vtake-off were homogenously distributed (r2 = 0.071). These results suggest that Vmax is a valid tool for estimating vertical jump height in a loaded jump squat test performed in a Smith machine. Key points Vertical jump height in the loaded jump squat can be estimated with acceptable precision from the maximum bar velocity recorded by a linear velocity transducer. The relationship between the point at which bar acceleration is less than -9.81 m·s-2 and the real take-off is affected by the velocity of movement. Mean propulsive velocity recorded by a linear velocity transducer does not appear to be optimal to monitor ballistic exercise performance. PMID:25983572

The dual function of barred plumage in birds: camouflage and communication.

PubMed

Gluckman, T L; Cardoso, G C

2010-11-01

A commonly held principle in visual ecology is that communication compromises camouflage: while visual signals are often conspicuous, camouflage provides concealment. However, some traits may have evolved for communication and camouflage simultaneously, thereby overcoming this functional compromise. Visual patterns generally provide camouflage, but it was suggested that a particular type of visual pattern – avian barred plumage – could also be a signal of individual quality. Here, we test if the evolution of sexual dimorphism in barred plumage, as well as differences between juvenile and adult plumage, indicate camouflage and/or signalling functions across the class Aves. We found a higher frequency of female- rather than male-biased sexual dimorphism in barred plumage, indicating that camouflage is its most common function. But we also found that, compared to other pigmentation patterns, barred plumage is more frequently biased towards males and its expression more frequently restricted to adulthood, suggesting that barred plumage often evolves or is maintained as a sexual communication signal. This illustrates how visual traits can accommodate the apparently incompatible functions of camouflage and communication, which has implications for our understanding of avian visual ecology and sexual ornamentation.

The intrinsic three-dimensional shape of galactic bars

NASA Astrophysics Data System (ADS)

Méndez-Abreu, J.; Costantin, L.; Aguerri, J. A. L.; de Lorenzo-Cáceres, A.; Corsini, E. M.

2018-06-01

We present the first statistical study on the intrinsic three-dimensional (3D) shape of a sample of 83 galactic bars extracted from the CALIFA survey. We use the galaXYZ code to derive the bar intrinsic shape with a statistical approach. The method uses only the geometric information (ellipticities and position angles) of bars and discs obtained from a multi-component photometric decomposition of the galaxy surface-brightness distributions. We find that bars are predominantly prolate-triaxial ellipsoids (68%), with a small fraction of oblate-triaxial ellipsoids (32%). The typical flattening (intrinsic C/A semiaxis ratio) of the bars in our sample is 0.34, which matches well the typical intrinsic flattening of stellar discs at these galaxy masses. We demonstrate that, for prolate-triaxial bars, the intrinsic shape of bars depends on the galaxy Hubble type and stellar mass (bars in massive S0 galaxies are thicker and more circular than those in less massive spirals). The bar intrinsic shape correlates with bulge, disc, and bar parameters. In particular with the bulge-to-total (B/T) luminosity ratio, disc g - r color, and central surface brightness of the bar, confirming the tight link between bars and their host galaxies. Combining the probability distributions of the intrinsic shape of bulges and bars in our sample we show that 52% (16%) of bulges are thicker (flatter) than the surrounding bar at 1σ level. We suggest that these percentages might be representative of the fraction of classical and disc-like bulges in our sample, respectively.

Search for the Standard Model Higgs Boson in ZH → v$$\\bar{v}$$b$$\\bar{b}$$ channel in p$$\\bar{p}$$ collisions at √s= 1.96 TeV

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

Dubey, Abhinav

2011-01-01

A search for the standard model Higgs boson is performed in 5.2 fb -1 of pmore » $$\\bar{p}$$ collisions at p √s = 1.96 TeV, collected with the DØ detector at the Fermilab Tevatron. The final state considered is a pair of b jets with large missing transverse energy, as expected from p$$\\bar{p}$$→ ZH → v$$\\bar{v}$$b$$\\bar{b}$$ production. The search is also sensitive to the WH → ℓvb$$\\bar{b}$$ channel, where the charged lepton is not identified. Boosted decision trees are used to discriminate signal from background. Good agreement is observed between data and expected backgrounds, and, for a Higgs-boson mass of 115 GeV, a limit is set at 95% C.L. on the cross section multiplied by branching fraction of (p$$\\bar{p}$$ → (Z/W)H) × (H → b$$\\bar{b}$$) that is a factor 4.57 expected and 3.73 observed larger than the value expected from the standard model.« less

Influence of pressure change during hydraulic tests on fracture aperture.

PubMed

Ji, Sung-Hoon; Koh, Yong-Kwon; Kuhlman, Kristopher L; Lee, Moo Yul; Choi, Jong Won

2013-03-01

In a series of field experiments, we evaluate the influence of a small water pressure change on fracture aperture during a hydraulic test. An experimental borehole is instrumented at the Korea Atomic Energy Research Institute (KAERI) Underground Research Tunnel (KURT). The target fracture for testing was found from the analyses of borehole logging and hydraulic tests. A double packer system was developed and installed in the test borehole to directly observe the aperture change due to water pressure change. Using this packer system, both aperture and flow rate are directly observed under various water pressures. Results indicate a slight change in fracture hydraulic head leads to an observable change in aperture. This suggests that aperture change should be considered when analyzing hydraulic test data from a sparsely fractured rock aquifer. © 2012, The Author(s). Groundwater © 2012, National Ground Water Association.

Unit-bar migration and bar-trough deposition: impacts on hydraulic conductivity and grain size heterogeneity in a sandy streambed

NASA Astrophysics Data System (ADS)

Korus, Jesse T.; Gilmore, Troy E.; Waszgis, Michele M.; Mittelstet, Aaron R.

2018-03-01

The hydrologic function of riverbeds is greatly dependent upon the spatiotemporal distribution of hydraulic conductivity and grain size. Vertical hydraulic conductivity ( K v) is highly variable in space and time, and controls the rate of stream-aquifer interaction. Links between sedimentary processes, deposits, and K v heterogeneity have not been well established from field studies. Unit bars are building blocks of fluvial deposits and are key to understanding controls on heterogeneity. This study links unit bar migration to K v and grain size variability in a sand-dominated, low-sinuosity stream in Nebraska (USA) during a single 10-day hydrologic event. An incipient bar formed parallel to the thalweg and was highly permeable and homogenous. During high flow, this bar was submerged under 10-20 cm of water and migrated 100 m downstream and toward the channel margin, where it became markedly heterogeneous. Low- K v zones formed in the subsequent heterogeneous bar downstream of the original 15-40-cm-thick bar front and past abandoned bridge pilings. These low- K v zones correspond to a discontinuous 1-cm layer of fine sand and silt deposited in the bar trough. Findings show that K v heterogeneity relates chiefly to the deposition of suspended materials in low-velocity zones downstream of the bar and obstructions, and to their subsequent burial by migration of the bar during high flow. Deposition of the unit bar itself, although it emplaced the vast majority of the sediment volume, was secondary to bar-trough deposition as a control on the overall pattern of heterogeneity.

Surface Interactions and Confinement of Methane: A High Pressure Magic Angle Spinning NMR and Computational Chemistry Study

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

Ok, Salim; Hoyt, David W.; Andersen, Amity

Characterization and modeling of the molecular-level behavior of simple hydrocarbon gases, such as methane, in the presence of both nonporous and nano-porous mineral matrices allows for predictive understanding of important processes in engineered and natural systems. In this study, changes in local electromagnetic environments of the carbon atoms in methane under conditions of high pressure (up to 130 bar) and moderate temperature (up to 346 K) were observed with 13C magic-angle spinning (MAS) NMR spectroscopy while the methane gas was mixed with two model solid substrates: a fumed non-porous, 12 nm particle size silica and a mesoporous silica with 200more » nm particle size and 4 nm average pore diameter. Examination of the interactions between methane and the silica systems over temperatures and pressures that include the supercritical regime was allowed by a novel high pressure MAS sample containment system, which provided high resolution spectra collected under in situ conditions. For pure methane, no significant thermal effects were found for the observed 13C chemical shifts at all pressures studied here (28.2 bar, 32.6 bar, 56.4 bar, 65.1 bar, 112.7 bar, and 130.3 bar). However, the 13C chemical shifts of resonances arising from confined methane changed slightly with changes in temperature in mixtures with mesoporous silica. The chemical shift values of 13C nuclides in methane change measurably as a function of pressure both in the pure state and in mixtures with both silica matrices, with a more pronounced shift when meso-porous silica is present. Molecular-level simulations utilizing GCMC, MD and DFT confirm qualitatively that the experimentally measured changes are attributed to interactions of methane with the hydroxylated silica surfaces as well as densification of methane within nanopores and on pore surfaces.« less

Water Drinking Test: Intraocular Pressure Changes after Tube Surgery and Trabeculectomy

PubMed Central

Razeghinejad, Mohammad Reza; Tajbakhsh, Zahra; Nowroozzadeh, Mohammad Hossein; Masoumpour, Masoumeh

2017-01-01

Purpose: To study the effects of filtration surgeries (tube and trabeculectomy) on changes in intraocular pressure after a water-drinking test. Methods: In this prospective, non-randomized, comparative clinical study, 30 patients who had tube surgery and 30 age- and sex-matched trabeculectomy patients underwent a water-drinking test. Only one eye of each patient was included. The baseline intraocular pressure was ≤21 mmHg in all enrolled eyes with or without adjunctive topical medications. After the water-drinking test, the intraocular pressure was measured and recorded at 15, 30, 45, and 60 minutes and the results were compared between the two groups. Results: In both groups, intraocular pressure significantly increased from baseline at all measured time-points (P < 0.001). In the trabeculectomy group, the average intraocular pressure increased from 14.8 ± 2.9 to 18.8 ± 4.7 mmHg at 30 minutes, but decreased at 60 min (18.0 ± 5.2 mmHg). In the Tube group, intraocular pressure increased incrementally until the last measurement (14.2 ± 3.9, 18.8 ± 5.6, and 19.7 ± 6.0 mmHg at baseline, 30, and 60 minutes, respectively). The end-pressure difference (intraocular pressure at 60 minutes vs. baseline) was significantly greater in the tube group (5.6 ± 3.6 mmHg; 41% change) than in the trabeculectomy group (3.2 ± 4.7; 23% change; P = 0.03). Conclusion: Intraocular pressure significantly increased after the water-drinking test in both the groups. Intraocular pressure started to decline 30 minutes after the water-drinking test in the trabeculectomy group, while it continued to increase up to 60 minutes in the Tube group. This finding may have implications regarding the efficacy or safety of the procedures in advanced glaucoma patients. PMID:29090048

Water Drinking Test: Intraocular Pressure Changes after Tube Surgery and Trabeculectomy.

PubMed

Razeghinejad, Mohammad Reza; Tajbakhsh, Zahra; Nowroozzadeh, Mohammad Hossein; Masoumpour, Masoumeh

2017-01-01

To study the effects of filtration surgeries (tube and trabeculectomy) on changes in intraocular pressure after a water-drinking test. In this prospective, non-randomized, comparative clinical study, 30 patients who had tube surgery and 30 age- and sex-matched trabeculectomy patients underwent a water-drinking test. Only one eye of each patient was included. The baseline intraocular pressure was ≤21 mmHg in all enrolled eyes with or without adjunctive topical medications. After the water-drinking test, the intraocular pressure was measured and recorded at 15, 30, 45, and 60 minutes and the results were compared between the two groups. In both groups, intraocular pressure significantly increased from baseline at all measured time-points ( P < 0.001). In the trabeculectomy group, the average intraocular pressure increased from 14.8 ± 2.9 to 18.8 ± 4.7 mmHg at 30 minutes, but decreased at 60 min (18.0 ± 5.2 mmHg). In the Tube group, intraocular pressure increased incrementally until the last measurement (14.2 ± 3.9, 18.8 ± 5.6, and 19.7 ± 6.0 mmHg at baseline, 30, and 60 minutes, respectively). The end-pressure difference (intraocular pressure at 60 minutes vs. baseline) was significantly greater in the tube group (5.6 ± 3.6 mmHg; 41% change) than in the trabeculectomy group (3.2 ± 4.7; 23% change; P = 0.03). Intraocular pressure significantly increased after the water-drinking test in both the groups. Intraocular pressure started to decline 30 minutes after the water-drinking test in the trabeculectomy group, while it continued to increase up to 60 minutes in the Tube group. This finding may have implications regarding the efficacy or safety of the procedures in advanced glaucoma patients.

Techno-economic Analysis of Acid Gas Removal and Liquefaction for Pressurized LNG

NASA Astrophysics Data System (ADS)

Lee, S. H.; Seo, Y. K.; Chang, D. J.