46 CFR 56.07-10 - Design conditions and criteria (modifies 101-104.7).

Code of Federal Regulations, 2010 CFR

2010-10-01

... ENGINEERING PIPING SYSTEMS AND APPURTENANCES Design § 56.07-10 Design conditions and criteria (modifies 101... system must not be greater than the internal design pressure defined in 104.1.2 of ASME B31.1 (incorporated by reference; see 46 CFR 56.01-2). (2) Where the maximum allowable working pressure of a system...

Fission product release and survivability of UN-kernel LWR TRISO fuel

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

T. M. Besmann; M. K. Ferber; H.-T. Lin

2014-05-01

A thermomechanical assessment of the LWR application of TRISO fuel with UN kernels was performed. Fission product release under operational and transient temperature conditions was determined by extrapolation from fission product recoil calculations and limited data from irradiated UN pellets. Both fission recoil and diffusive release were considered and internal particle pressures computed for both 650 and 800 um diameter kernels as a function of buffer layer thickness. These pressures were used in conjunction with a finite element program to compute the radial and tangential stresses generated within a TRISO particle undergoing burnup. Creep and swelling of the inner andmore » outer pyrolytic carbon layers were included in the analyses. A measure of reliability of the TRISO particle was obtained by computing the probability of survival of the SiC barrier layer and the maximum tensile stress generated in the pyrolytic carbon layers from internal pressure and thermomechanics of the layers. These reliability estimates were obtained as functions of the kernel diameter, buffer layer thickness, and pyrolytic carbon layer thickness. The value of the probability of survival at the end of irradiation was inversely proportional to the maximum pressure.« less

D0 Silicon Upgrade: ASME Code and Pressure Calculations for Liquid Nitrogen Subcooler

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

Kuwazaki, Andrew; Leicht, Todd; /Fermilab

1995-10-04

Included in this engineering note are three separate calculation divisions. The first calculations are the determination of the required thickness of the LN{sub 2} subcooler flat head according to ASME code. This section includes Appendix A-C. The minimum plate thickness determined was 0.563 in. The actual thickness chosen in fabrication was a 3/4-inch plate milled to 0.594-inch at the bolt circle. Along with the plate thickness, this section calculates the required reinforcement area at the top plate penetrations. It was found that a 1/4-inch fillet weld at each penetration was adequate. The next set of calculations were done to provemore » that the subcooler internal pressure will always be less than 15 psig and therefore will not be classified as a pressure vessel. The subcooler is always open to a vent pipe. Appendix D calculations show that the vent pipe has a capacity of 1042 lbs/hr if 15 psig is present at the subcooler. It goes on to show that the inlet piping would at that flow rate, see a pressure drop of 104 psig. The maximum supply pressure of the LN{sub 2} storage dewar is 50 psig. Appendix E addresses required flow rates for steady state, loss of vacuum, or fire conditions. Page E9 shows a summary which states the maximum pressure would be 1.50 psig at fire conditions and internal pressure.« less

Viscoelastic/damage modeling of filament-wound spherical pressure vessels

NASA Technical Reports Server (NTRS)

Hackett, Robert M.; Dozier, Jan D.

1987-01-01

A model of the viscoelastic/damage response of a filament-wound spherical vessel used for long-term pressure containment is developed. The matrix material of the composite system is assumed to be linearly viscoelastic. Internal accumulated damage based upon a quadratic relationship between transverse modulus and maximum circumferential strain is postulated. The resulting nonlinear problem is solved by an iterative routine. The elastic-viscoelastic correspondence is employed to produce, in the Laplace domain, the associated elastic solution for the maximum circumferential strain which is inverted by the method of collocation to yield the time-dependent solution. Results obtained with the model are compared to experimental observations.

Burst pressure investigation of filament wound type IV composite pressure vessel

NASA Astrophysics Data System (ADS)

Farhood, Naseer H.; Karuppanan, Saravanan; Ya, H. H.; Baharom, Mohamad Ariff

2017-12-01

Currently, composite pressure vessels (PVs) are employed in many industries such as aerospace, transportations, medical etc. Basically, the use of PVs in automotive application as a compressed natural gas (CNG) storage cylinder has been growing rapidly. Burst failure due to the laminate failure is the most critical failure mechanism for composite pressure vessels. It is predominantly caused by excessive internal pressure due to an overfilling or an overheating. In order to reduce fabrication difficulties and increase the structural efficiency, researches and studies are conducted continuously towards the proper selection of vessel design parameters. Hence, this paper is focused on the prediction of first ply failure pressure for such vessels utilizing finite element simulation based on Tsai-Wu and maximum stress failure criterions. The effects of laminate stacking sequence and orientation angle on the burst pressure were investigated in this work for a constant layered thickness PV. Two types of winding design, A [90°2/∓θ16/90°2] and B [90°2/∓θ]ns with different orientations of helical winding reinforcement were analyzed for carbon/epoxy composite material. It was found that laminate A sustained a maximum burst pressure of 55 MPa for a sequence of [90°2/∓15°16/90°2] while the laminate B returned a maximum burst pressure of 45 MPa corresponding to a stacking sequence of [90°2/±15°/90°2/±15°/90°2/±15° ....] up to 20 layers for a constant vessel thickness. For verification, a comparison was done with the literature under similar conditions of analysis and good agreement was achieved with a maximum difference of 4% and 10% for symmetrical and unsymmetrical layout, respectively.

Pressures generated in vitro during Stabident intraosseous injections.

PubMed

Whitworth, J M; Ramlee, R A M; Meechan, J G

2005-05-01

To test the hypothesis that the Stabident intraosseous injection is a potentially high-pressure technique, which carries serious risks of anaesthetic cartridge failure. A standard Astra dental syringe was modified to measure the internal pressure of local anaesthetic cartridges during injection. Intra-cartridge pressures were measured at 1 s intervals during slow (approximately 15 s) and rapid (<10 s) injections of 2% Xylocaine with 1:80,000 adrenaline (0.25 cartridge volumes) into air (no tissue resistance), or into freshly prepared Stabident perforation sites in the anterior mandible of freshly culled young and old sheep (against tissue resistance). Each injection was repeated 10 times over 3 days. Absolute maximum pressures generated by each category of injection, mean pressures at 1 s intervals in each series of injections, and standard deviations were calculated. Curves of mean maximum intra-cartridge pressure development with time were plotted for slow and rapid injections, and one-way anova (P<0.05) conducted to determine significant differences between categories of injection. Pressures created when injecting into air were less than those needed to inject into tissue (P<0.001). Fast injection produced greater intra-cartridge pressures than slow delivery (P<0.05). Injection pressures rose more quickly and to higher levels in small, young sheep mandibles than in larger, old sheep mandibles. The absolute maximum intra-cartridge pressure developed during the study was 3.31 MPa which is less than that needed to fracture glass cartridges. Stabident intraosseous injection conducted in accordance with the manufacturer's instructions does not present a serious risk of dangerous pressure build-up in local anaesthetic cartridges.

Comparison of Electrotherapy, Rubber Band Ligation and Hemorrhoidectomy in the Treatment of Hemorrhoids: A Clinical and Manometric Study

PubMed Central

Izadpanah, A; Hosseini, SV; Mahjoob, M

2010-01-01

BACKGROUND Treatment of hemorrhoid disease is one of the most challenging fields in general surgery in which different methods are used to treat this condition. In this study, we compared the manometric and clinical results of three treatment methods for hemorrhoids. METHODS A total of 150 patients with symptomatic grades II or III internal hemorrhoids were randomly assigned to three groups. Group A underwent Ferguson hemorrhoidectomy, group B were treated with rubber band ligation (RBL) and group C were treated with direct current electrotherapy. RESULTS Preoperatively, grade III hemorrhoids had significantly higher mean resting pressure and mean squeezing pressure in comparison to grade II hemorrhoids. After hemorrhoidectomy, patients in group A had a significant decrease in the maximum resting pressure (90.8 to 77.7 mmHg) and maximum squeezing pressure (130.6 to 114.8 mmHg) with a significant raise in the volume of the first sensation. However there was no significant change in manometric indexes after RBL and electrotherapy. Group A patients had more postoperative pain and itching compared to groups B and C. CONCLUSION We conclude that electrotherapy is a safe, effective and simple method of treating grades II and III uncomplicated internal hemorrhoids. This procedure is associated with little postoperative pain and complications, and has the least changes in anorectal manometric characteristics. Therefore electrotherapy may be recommended as a treatment of choice for grades II and III uncomplicated internal hemorrhoids. PMID:25197506

Space Shuttle Redesigned Solid Rocket Motor nozzle natural frequency variations with burn time

NASA Technical Reports Server (NTRS)

Lui, C. Y.; Mason, D. R.

1991-01-01

The effects of erosion and thermal degradation on the Space Shuttle Redesigned Solid Rocket Motor (RSRM) nozzle's structural dynamic characteristics were analytically evaluated. Also considered was stiffening of the structure due to internal pressurization. A detailed NASTRAN finite element model of the nozzle was developed and used to evaluate the influence of these effects at several discrete times during motor burn. Methods were developed for treating erosion and thermal degradation, and a procedure was developed to account for internal pressure stiffening using differential stiffness matrix techniques. Results were verified using static firing test accelerometer data. Fast Fourier Transform and Maximum Entropy Method techniques were applied to the data to generate waterfall plots which track modal frequencies with burn time. Results indicate that the lower frequency nozzle 'vectoring' modes are only slightly affected by erosion, thermal effects and internal pressurization. The higher frequency shell modes of the nozzle are, however, significantly reduced.

Excessive glenohumeral horizontal abduction as occurs during the late cocking phase of the throwing motion can be critical for internal impingement.

PubMed

Mihata, Teruhisa; McGarry, Michelle H; Kinoshita, Mitsuo; Lee, Thay Q

2010-02-01

The objective of this study was to determine the effects of increased horizontal abduction with maximum external rotation, as occurs during the late cocking phase of throwing motion, on shoulder internal impingement. An increase in glenohumeral horizontal abduction will cause overlap of the rotator cuff insertion with respect to the glenoid and increase pressure between the supraspinatus and infraspinatus tendon insertions on the greater tuberosity and the glenoid. Controlled laboratory study. Eight cadaveric shoulders were tested with a custom shoulder testing system with the specimens in 60 degrees of glenohumeral abduction and maximum external rotation. The amount of internal impingement was evaluated by assessing the location of the supraspinatus and infraspinatus articular insertions on the greater tuberosity relative to the glenoid using a MicroScribe 3DLX. Pressure in the posterior-superior quadrant of the glenoid was measured using Fuji prescale film. Data were obtained with the humerus in the scapular plane and 15 degrees , 30 degrees , and 45 degrees of horizontal abduction from the scapular plane. At 30 degrees and 45 degrees of horizontal abduction, the articular margin of the supraspinatus and infraspinatus tendons was anterior to the posterior edge of the glenoid and less than 2 mm from the glenoid rim in the lateral direction; the contact pressure was also greater than that found in the scapular plane and 15 degrees of horizontal abduction. Conclusion Horizontal abduction beyond the coronal plane increased the amount of overlap and contact pressure between the supraspinatus and infraspinatus tendons and glenoid. Excessive glenohumeral horizontal abduction beyond the coronal plane may cause internal impingement, which may lead to rotator cuff tears and superior labral anterior to posterior (SLAP) lesions.

Anal endosonography and manometry: comparison in patients with defecation problems.

PubMed

Schäfer, R; Heyer, T; Gantke, B; Schäfer, A; Frieling, T; Häussinger, D; Enck, P

1997-03-01

Correlations between anal sphincter function as assessed by anorectal manometry and anal sphincter anatomy measured by endoluminal ultrasound have been reported in the literature both for patients and for healthy individuals but have not been confirmed by other authors. For a larger series of patients (152 consecutive patients, mean age 54.1 +/- 15.5 years; female:male ratio, 111:41) with anorectal dysfunctions such as incontinence (n = 92), constipation (n = 37), and other symptoms (n = 23), diagnostic work-up included conventional multilumen anorectal manometry to evaluate internal sphincter pressure at rest, maximum external sphincter squeeze pressure during contraction, and endoanal sonography to determine anal sphincter integrity and to measure dorsal, left lateral, and right lateral diameter of the internal anal sphincter (IAS) and external anal sphincter (EAS) muscles. Maximum squeeze pressure was significantly correlated to muscle thickness of the EAS (P = 0.001). No association was found between resting pressure and IAS diameter. Women had significantly lower resting and squeeze pressures than men (P = 0.008 and P = 0.003, respectively), but age-related changes of function were only found for resting pressure. Endosonographic values of IAS and EAS did not differ between genders but were significantly correlated with age (P = 0.008 and P = 0.02, respectively). Because all correlations were rather weak, they only can explain a small portion of data variance. Anal manometry and anal ultrasound, therefore, are of complementary value and are both indicated in adequate clinical problems.

Fire safety arrangement of inhabited pressurized compartments of manned spacecraft

NASA Astrophysics Data System (ADS)

Bolodian, Ivan; Melikhov, Anatoliy; Tanklevskiy, Leonid

2017-06-01

The article deals with innovative technical solutions that provide fire safety in inhabited pressurized compartments of manned spacecraft by means of a fireproof device of inhabited pressurized compartments via application of engineering means of fire prevention and fire spreading prevention by lowering fire load in an inhabited pressurized module up to the point when the maximum possible levels of fire factors in an inhabited pressurized compartment of a manned spacecraft are prevented. Represented technical solutions are used at the present time according to stated recommendations during provision of fire safety of equipment created by a number of Russian organizations for equipage of inhabited pressurized compartments of spacecraft of the Russian segment of International space station.

Predicting Large-scale Effects During Cookoff of Plastic-Bonded Explosives (PBX 9501 PBX 9502 and LX-14)

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

Hobbs, Michael L.; Kaneshige, Michael J.; Erikson, William W.

In this study, we have made reasonable cookoff predictions of large-scale explosive systems by using pressure-dependent kinetics determined from small-scale experiments. Scale-up is determined by properly accounting for pressure generated from gaseous decomposition products and the volume that these reactive gases occupy, e.g. trapped within the explosive, the system, or vented. The pressure effect on the decomposition rates has been determined for different explosives by using both vented and sealed experiments at low densities. Low-density explosives are usually permeable to decomposition gases and can be used in both vented and sealed configurations to determine pressure-dependent reaction rates. In contrast, explosivesmore » that are near the theoretical maximum density (TMD) are not as permeable to decomposition gases, and pressure-dependent kinetics are difficult to determine. Ignition in explosives at high densities can be predicted by using pressure-dependent rates determined from the low-density experiments as long as gas volume changes associated with bulk thermal expansion are also considered. In the current work, cookoff of the plastic-bonded explosives PBX 9501 and PBX 9502 is reviewed and new experimental work on LX-14 is presented. Reactive gases are formed inside these heated explosives causing large internal pressures. The pressure is released differently for each of these explosives. For PBX 9501, permeability is increased and internal pressure is relieved as the nitroplasticizer melts and decomposes. Internal pressure in PBX 9502 is relieved as the material is damaged by cracks and spalling. For LX-14, internal pressure is not relieved until the explosive thermally ignites. The current paper is an extension of work presented at the 26th ICDERS symposium [1].« less

Exploratory Investigation of the Effects of Boundary-Layer Control on the Pressure-Recovery Characteristics of a Circular Internal-Contraction Inlet with Translating Centerbody at Mach Numbers of 2.00 and 2.35

NASA Technical Reports Server (NTRS)

Martin, Norman J.

1959-01-01

Exploratory tests of a circular internal-contraction inlet were made at Mach numbers of 2.00 and 2.35 to determine the effect of a cowl-type boundary-layer control located downstream of the inlet throat. The inlet was designed for a Mach number of 2.5. Tests were also made of the inlet modified to correspond to design Mach numbers of 2.35 and 2.25. Surveys near the minimum area section of the inlet without boundary-layer control indicated maximum averaged pressure recoveries between 0.90 and 0.92 at a free-stream Mach number, M(sub infinity), of 2.35 for the inlets. Farther downstream, after partial subsonic diffusion, a maximum pressure recovery of 0.842 was obtained with the inlet at M(sub infinity) = 2.35. The pressure recovery of the inlet was increased by 0.03 at a Mach number of 2.35 and decreased by 0.02 at a Mach number of 2.00 by the application of cowl-type boundary-layer control. Further investigation with the inlet without bleed demonstrated that an increase of angle of attack from 0 deg to 3 deg reduced the pressure recovery 0.04. The effect of Reynolds number was to increase pressure recovery 0.07 (from 0.785 to 0.855) with an increase in Reynolds number (based on inlet diameter) from 0.79 x 10(exp 6) to 3.19 x 10(exp 6).

30 CFR 36.25 - Engine exhaust system.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Engine exhaust system. 36.25 Section 36.25... EQUIPMENT Construction and Design Requirements § 36.25 Engine exhaust system. (a) Construction. The exhaust system of the engine shall be designed to withstand an internal pressure equal to 4 times the maximum...

Effects of a prostagrandin EP4-receptor agonist ONO-AE1-329 on the left ventricular pressure-volume relationship in the halothane-anesthetized dogs.

PubMed

Honda, Atsushi; Nakamura, Yuji; Ohara, Hiroshi; Cao, Xin; Nomura, Hiroaki; Katagi, Jun; Wada, Takeshi; Izumi-Nakaseko, Hiroko; Ando, Kentaro; Sugiyama, Atsushi

2016-03-15

Cardiac effects of a prostagrandin EP4-receptor agonist ONO-AE1-329 were assessed in the halothane-anesthetized dogs under the monitoring of left ventricular pressure-volume relationship, which were compared with those of clinically recommended doses of dopamine, dobutamine and milrinone (n=4-5 for each treatment). ONO-AE1-329 was intravenously administered in doses of 0.3, 1 and 3 ng/kg/min for 10 min with a pause of 20 min. Dopamine in a dose of 3 µg/kg/min for 10 min, dobutamine in a dose of 1 µg/kg/min for 10 min and milrinone in a dose of 5 µg/kg/min for 10 min followed by 0.5 µg/kg/min for 10 min were intravenously administered. Low dose of ONO-AE1-329 increased the stroke volume. Middle dose of ONO-AE1-329 increased the cardiac output, left ventricular end-diastolic volume, ejection fraction, maximum upstroke/downstroke velocities of the left ventricular pressure and external work, but decreased the end-systolic pressure and internal work besides the change by the low dose. High dose of ONO-AE1-329 increased the heart rate and maximum elastance, but decreased the end-systolic volume besides the changes by the middle dose. Dopamine, dobutamine and milrinone exerted essentially similar cardiac effects to ONO-AE1-329, but they did not significantly change the end-diastolic volume, end-systolic volume, stroke volume, ejection fraction, end-systolic pressure, maximum elastance, external work or internal work. Thus, EP4-receptor stimulation by ONO-AE1-329 may have potential to better promote the passive ventricular filling than the conventional cardiotonic drugs, which could become a candidate of novel therapeutic strategy for the treatment of heart failure with preserved ejection fraction. Copyright © 2016 Elsevier B.V. All rights reserved.

A Comparative Study of Cycle Variability of Laser Plug Ignition vs Classical Spark Plug Ignition in Combustion Engines

NASA Astrophysics Data System (ADS)

Done, Bogdan

2017-10-01

Over the past 30 years numerous studies and laboratory experiments have researched the use of laser energy to ignite gas and fuel-air mixtures. The actual implementation of this laser application has still to be fully achieved in a commercial automotive application. Laser Plug Ignition as a replacement for Spark Plug Ignition in the internal combustion engines of automotive vehicles, offers several potential benefits such as extending lean burn capability, reducing the cyclic variability between combustion cycles and decreasing the total amount of ignition costs, and implicitly weight and energy requirements. The paper presents preliminary results of cycle variability study carried on a SI Engine equipped with laser Plug Ignition system. Versus classic ignition system, the use of the laser Plug Ignition system assures the reduction of the combustion process variability, reflected in the lower values of the coefficient of variability evaluated for indicated mean effective pressure, maximum pressure, maximum pressure angle and maximum pressure rise rate. The laser plug ignition system was mounted on an experimental spark ignition engine and tested at the regime of 90% load and 2800 rev/min, at dosage of λ=1.1. Compared to conventional spark plug, laser ignition assures the efficiency at lean dosage.

Risk factors correlated with plantar pressure in Chinese patients with type 2 diabetes.

PubMed

Qiu, Xuan; Tian, De-Hu; Han, Chang-Ling; Chen, Wei; Wang, Zhan-Jian; Mu, Zhen-Yun; Li, Xu; Liu, Kuan-Zhi

2013-12-01

Plantar pressure is a key factor for predicting ulceration in the foot of a diabetes patient. We recruited a group of 100 Chinese patients with type 2 diabetes and an age-, sex-, weight-, and height-matched group of 100 Chinese subjects without diabetes. We obtained plantar pressure data using a Footscan(®) gait system (RsScan International, Olen, Belgium) when the subjects with and without diabetes walked barefoot across a sensor platform. We recorded the maximum force, maximum pressure, impulse, pressure-time integral, and loading rate from 10 regions of the foot. We collected the data of 11 history-based variables, 10 anthropometric variables, and three metabolic variables regarding the clinical characteristics of the diabetes patients. Weight was identified as a determining factor for high plantar pressure. Height, the Neuropathy Symptom Score (NSS), and ankle-brachial index (ABI) were correlated positively with plantar pressure measurements, respectively. The sex, history of ulcer and callus, intima-media membrane of the lower limb blood vessels, and fasting blood glucose (FBG) could also explain a portion of the variability of the plantar pressure measurements. However, the correlations were low or weak. High plantar pressure in diabetes patients could be predicted, in part, based on weight, height, NSS, ABI, sex, history of ulcer and callus, intima-media membrane of the lower limb blood vessels, and FBG. Therefore, interventions should be taken specifically before high plantar pressure emerges.

Influence of Exercise Modality on Cerebral-Ocular Hemodynamics and Pressures

NASA Technical Reports Server (NTRS)

Scott, J.; Martin, D.; Crowell, B.; Goetchius, E.; Seponski, C.; Gonzales, R.; Matz, T.; Ploutz-Snyder, R.; Stenger, M.; Ploutz-Snyder, L.

2016-01-01

Background: Moderate and high intensity aerobic or resistance exercise has clearly identified benefits for cardiac, muscle, and bone health. However, the impact of such exercise - either as a mitigating or an exacerbating factor - on the development of the visual impairment and intracranial pressure syndrome (VIIP) is unknown. Accordingly, our aim was to characterize the effect of an acute bout of resistance (RE), moderate-intensity continuous (CE), and high-intensity interval exercise (IE) during a cephalad fluid shift on cerebral-ocular hemodynamics and pressures. Methods: 10 male subjects (36 plus or minus 9 years) completed 4 testing days in a 15 degree head-down tilt (HDT): (1) assessment of maximum volume of O (sub 2), (2) RE session (4 sets of 12 repetition maximum leg press exercise), (3) CE session (30 minutes of cycling at 60 percent maximum volume of O (sub 2)), and (4) IE session (4 by 4-minute intervals of exercise at 85 percent maximum volume of O (sub 2) with 3-minute active rest periods). During each session, blood flow (Vivid-e, GE Healthcare) in extracranial arteries (common carotid artery, CCA; internal carotid artery, ICA; external carotid artery, ECA and vertebral artery, VA), and mean blood flow velocity in middle cerebral artery (MCA), internal jugular pressure (IJP; VeinPress), and intraocular pressure (IOP; Icare PRO) were measured at rest, at the end of each resistance or interval set, and every 5 minutes during continuous exercise. Translaminar pressure gradient (TLPG) was estimated by subtracting IJP from IOP. Results: There were no differences across days in pre-exercise resting blood flows or pressures. IOP decreased slightly from HDT rest (20.2 plus or minus 2.3 millimeters of mercury) to exercise (RE: 19.2 plus or minus 2.8 millimeters of mercury; CE: 18.9 plus or minus 3.2 millimeters of mercury; IE: 20.1 plus or minus 2.8 millimeters of mercury), while IJP decreased during CE (31.6 plus or minus 9.5 millimeters of mercury) and RE (32.0 plus or minus 8.1 millimeters of mercury), and increased during IE (35.1 plus or minus 9.5 millimeters of mercury) from HDT rest (33.3 plus or minus 6.5 millimeters of mercury). Estimated TLPG was increased during IE only. Compared to RE and CE, IE resulted in the greatest increase in MCA blood flow velocity and extracranial artery blood flow. Conclusions: These preliminary results suggest that high-intensity IE acutely increases cerebral blood flow, IJP, and TLPG. Alterations in TLPG is one mechanism that may contribute to optic nerve sheath edema in astronauts. Accordingly, acutely raising IOP and/or orbital pressure during exercise could optimize cerebral-ocular pressures during spaceflight.

49 CFR 180.416 - Discharge system inspection and maintenance program for cargo tanks transporting liquefied...

Code of Federal Regulations, 2010 CFR

2010-10-01

... with a unique identification number and maximum working pressure. (c) Post-delivery hose check. After... during the unloading. (d) Monthly inspections and tests. (1) The operator must visually inspect each... operator must actuate all emergency discharge control devices designed to close the internal self-closing...

49 CFR 180.416 - Discharge system inspection and maintenance program for cargo tanks transporting liquefied...

Code of Federal Regulations, 2011 CFR

2011-10-01

... unique identification number and maximum working pressure. (c) Post-delivery hose check. After each... unloading. (d) Monthly inspections and tests. (1) The operator must visually inspect each delivery hose... actuate all emergency discharge control devices designed to close the internal self-closing stop valve to...

49 CFR 180.416 - Discharge system inspection and maintenance program for cargo tanks transporting liquefied...

Code of Federal Regulations, 2014 CFR

2014-10-01

... unique identification number and maximum working pressure. (c) Post-delivery hose check. After each... unloading. (d) Monthly inspections and tests. (1) The operator must visually inspect each delivery hose... actuate all emergency discharge control devices designed to close the internal self-closing stop valve to...

49 CFR 180.416 - Discharge system inspection and maintenance program for cargo tanks transporting liquefied...

Code of Federal Regulations, 2013 CFR

2013-10-01

... unique identification number and maximum working pressure. (c) Post-delivery hose check. After each... unloading. (d) Monthly inspections and tests. (1) The operator must visually inspect each delivery hose... actuate all emergency discharge control devices designed to close the internal self-closing stop valve to...

49 CFR 180.416 - Discharge system inspection and maintenance program for cargo tanks transporting liquefied...

Code of Federal Regulations, 2012 CFR

2012-10-01

... unique identification number and maximum working pressure. (c) Post-delivery hose check. After each... unloading. (d) Monthly inspections and tests. (1) The operator must visually inspect each delivery hose... actuate all emergency discharge control devices designed to close the internal self-closing stop valve to...

Cylinder pressure reconstruction based on complex radial basis function networks from vibration and speed signals

NASA Astrophysics Data System (ADS)

Johnsson, Roger

2006-11-01

Methods to measure and monitor the cylinder pressure in internal combustion engines can contribute to reduced fuel consumption, noise and exhaust emissions. As direct measurements of the cylinder pressure are expensive and not suitable for measurements in vehicles on the road indirect methods which measure cylinder pressure have great potential value. In this paper, a non-linear model based on complex radial basis function (RBF) networks is proposed for the reconstruction of in-cylinder pressure pulse waveforms. Input to the network is the Fourier transforms of both engine structure vibration and crankshaft speed fluctuation. The primary reason for the use of Fourier transforms is that different frequency regions of the signals are used for the reconstruction process. This approach also makes it easier to reduce the amount of information that is used as input to the RBF network. The complex RBF network was applied to measurements from a 6-cylinder ethanol powered diesel engine over a wide range of running conditions. Prediction accuracy was validated by comparing a number of parameters between the measured and predicted cylinder pressure waveform such as maximum pressure, maximum rate of pressure rise and indicated mean effective pressure. The performance of the network was also evaluated for a number of untrained running conditions that differ both in speed and load from the trained ones. The results for the validation set were comparable to the trained conditions.

First gaseous Sulfur (VI) measurements in the simulated internal flow of an aircraft gas turbine engine during project PartEmis

NASA Astrophysics Data System (ADS)

Katragkou, E.; Wilhelm, S.; Arnold, F.; Wilson, C.

2004-01-01

Gaseous S(VI) (SO3 + H2SO4) has been measured by chemical ionization mass spectrometry (CIMS) in the simulated internal flow of an aircraft gas turbine in a test rig at ground level during the PartEmis 2002 campaign. Building on S(VI) and calculated total sulfur ST the abundance ratio ɛ = S(VI)/ST was determined. The measurements to be reported here were made at two sampling points, for two engine test conditions representative of old and modern aircraft cruise and for a fuel sulfur content FSC = 1270 ppm. For both cruise conditions the measured ɛ increased with increasing exhaust age from the high pressure to the low pressure stage. For each pressure stage ɛ was higher in the modern cruise condition. The maximum ɛ (2.3 +/- 1.2%) was obtained for modern cruise and the low pressure stage. Our present data suggest that modern engines have a somewhat higher conversion efficiencies than old engines.

The induction of water to the inlet air as a means of internal cooling in aircraft-engine cylinders

NASA Technical Reports Server (NTRS)

Rothrock, Addison M; Krsek, Alois, Jr; Jones, Anthony W

1943-01-01

Report presents the results of investigations conducted on a full-scale air-cooled aircraft-engine cylinder of 202-cubic inch displacement to determine the effects of internal cooling by water induction on the maximum permissible power and output of an internal-combustion engine. For a range of fuel-air and water-fuel ratios, the engine inlet pressure was increased until knock was detected aurally, the power was then decreased 7 percent holding the ratios constant. The data indicated that water was a very effective internal coolant, permitting large increases in engine power as limited by either knock or by cylinder temperatures.

The Pressurized Logistics Module: Providing Consumables and Resupply Logistics to the Lunar Surface for a Long-duration Manned Mission

NASA Technical Reports Server (NTRS)

Carpenter, Amanda; Knight, Amanda

2008-01-01

In response to President Bush s 2004 Vision for Space Exploration initiative, NASA established an agency-wide Lunar Architecture Team (LAT) to develop the high-level requirements, assumptions, ground-rules and objectives for a manned mission to the moon. During Phase II of the evaluation, the Habitation Focus Element Group was directed to conceptually develop and design a Pressurized Logistics Module (PLM). The PLM task was delivered with one major requirement: to derive a system with minimal mass and cost, and a maximum, functional, internal volumetric area in order to provide the maximum amount of consumables, supportability and logistic re-supply for a crew of four to the Lunar surface with an overall integrated maximum weight of 5200kg. The PLM was derived from the Habitation Group s "mini-Hab" option. This concept required that the PLM have an aluminum-clad graphite epoxy external truss, utilized for increased mobility and stability, which would encompass a 2.7 meter diameter pressurized aluminum-lithium cylinder. Several trade studies and analyses were performed to determine the final length and orientation of the module, the number of systems required to maintain the PLM, and the number of hatches/mating mechanisms which would successfully and efficiently meet the requirements. Of the five specific configurations assessed, the PLM was determined to have a 3 meter by 3 meter by 5 meter external truss with a 2.7 meter diameter and 5 meter long horizontal, pressurized cylinder with one hatch/mating mechanism on one end cone. Two major assumptions aided in the formulation of the technical baseline: 1) the PLM should be sustainable for up to 18 months on the Lunar Lander without connection to its final destination, the Lunar Outpost, and 2) it must be self-sufficient to withstand a maximum eight hour transit from the Lander to the Outpost. Per these assumptions, eight major systems constitute the PLM: structures, passive mating, protection, power, thermal, avionics, life support and outfitting. Including a conservative 20% growth, the overall estimated tare weight for the PLM was determined to be 2181kg. The tare weight of the design allowed the available internal volume of the cylinder with a 0.20 meter high floor to transport the maximum of either 176 single Crew Transfer Bags (CTBs) or 3019kg.

Experimental Pressure Distributions on Axisymmetric Cowls at Mach Numbers From 0.60 to 0.92

NASA Technical Reports Server (NTRS)

Re, Richard J.

2006-01-01

Pressure distributions on four nacelle cowl models of the same length and highlight area but different geometries external to the highlight are compared. The diameter ratio (ratio of highlight diameter to maximum diameter) of the four cowls was 0.854 and the length ratio (ratio of cowl length to maximum diameter) was 0.439. The cowls had the same internal geometry from the highlight to the throat with a contraction ratio (ratio of highlight area to throat area) of 1.250. Data for two other cowls which had a diameter ratio of 0.880, a length ratio of 0.400 and a contraction ratio 1.250 are also included. All the cowls had rows of static pressure orifices on the top and bottom surfaces. Mass-flow ratio was varied between 0.27 and 0.93. Some data were obtained between angles of attack from -2.1deg and 4.1deg. The test was conducted in the Langley 16-Foot Transonic Tunnel.

CooLN2Car: An Experimental Car Which Uses Liquid Nitrogen as Its Fuel

NASA Astrophysics Data System (ADS)

Parker, M. E.; Plummer, M. C.; Ordonez, C. A.

1997-10-01

A ``cryogenic" heat engine which operates using the atmosphere as a heat source and a cryogenic medium as a heat sink has been incorporated as the power system for an automobile. A 1973 Volkswagen Beetle has been converted and uses liquid nitrogen as its ``fuel." A Dewar was mounted in the car and provides nitrogen under pressure to two heat exchangers connected in parallel which use atmospheric heat to heat the nitrogen. The heat exchangers deliver compressed nitrogen gas to a vane-type pneumatic motor mounted in place of the original gasoline engine. Pressure in the tank is maintained internally at 1.2 MPa and is reduced to 0.7 MPa before the motor by a pressure regulator. A throttle, composed of a butterfly valve, is mounted between the regulator and the motor and is connected to the driver's accelerator peddle. The vehicle has good acceleration, a maximum range of 15 miles, and a maximum speed of 25 mph. A demonstration with the vehicle is planned.

Internal sphincter and the nature of haemorrhoids.

PubMed Central

Hancock, B D

1977-01-01

Internal anal sphincter activity has been studied in 84 patients with haemorrhoids and 40 asymptomatic subjects. Activity was estimated by measuring maximum resting anal pressure with a water filled anal balloon probe 7 mm in diameter connected to a strain gauge pressure transducer. There was greater activity of the internal sphincter in patients with haemorrhoids than in controls, but there was no significant relationship between sphincter activity and duration of symptoms, predominant symptom (bleeding or prolapse), severity of symptoms, history of pain, history of straining at stool, or size of haemorrhoids. Straining at stool occurred significantly more often in patients whose main complaint was prolapse than in those whose main complaint was bleeding. Anal dilatation reduced sphincter activity and the best clinical results were obtained in those with the most active sphincter. An internal sphincter abnormality may be an aetiological factor in some patients but there must be other factors as well. Straining at stool may determine whether bleeding or prolapse is the predominant symptom. Images Fig. 1 PMID:892612

Analytical Modeling of Pressure Wall Hole Size and Maximum Tip-to-Tip Crack Length for Perforating Normal and Oblique Orbital Debris Impacts

NASA Technical Reports Server (NTRS)

Schonberg, William P.; Mohamed, Essam

1997-01-01

This report presents the results of a study whose objective was to develop first-principles-based models of hole size and maximum tip-to-tip crack length for a spacecraft module pressure wall that has been perforated in an orbital debris particle impact. The hole size and crack length models are developed by sequentially characterizing the phenomena comprising the orbital debris impact event, including the initial impact, the creation and motion of a debris cloud within the dual-wall system, the impact of the debris cloud on the pressure wall, the deformation of the pressure wall due to debris cloud impact loading prior to crack formation, pressure wall crack initiation, propagation, and arrest, and finally pressure wall deformation following crack initiation and growth. The model development has been accomplished through the application of elementary shock physics and thermodynamic theory, as well as the principles of mass, momentum, and energy conservation. The predictions of the model developed herein are compared against the predictions of empirically-based equations for hole diameters and maximum tip-to-tip crack length for three International Space Station wall configurations. The ISS wall systems considered are the baseline U.S. Lab Cylinder, the enhanced U.S. Lab Cylinder, and the U.S. Lab Endcone. The empirical predictor equations were derived from experimentally obtained hole diameters and crack length data. The original model predictions did not compare favorably with the experimental data, especially for cases in which pressure wall petalling did not occur. Several modifications were made to the original model to bring its predictions closer in line with the experimental results. Following the adjustment of several empirical constants, the predictions of the modified analytical model were in much closer agreement with the experimental results.

Experimental study of planetary gases with applications to planetary interior models

NASA Technical Reports Server (NTRS)

Bell, Peter M.; Mao, Ho-Kwang

1988-01-01

High-pressure experimental data on planetary materials are critical in developing planetary models and in addressing otherwise insoluble problems of the internal structure of the major planets. Progress in the last five years has been particularly marked. Maximum static pressure of 550 GPa was achieved. For the first time, X-ray diffraction of solidified gases (Ne, Xe) and ices (H2O) were obtained at pressures above one megabar, single-crystal diffraction of ultralight elements (H2, He) were detected up to 25 GPa, pressures over 200 GPa at 77 K were reached in solid hydrogen, including the discovery of a phase transformation in the molecular solid. Advances in instrumentation and new measurements performed during 1983 to 1988 are summarized.

Size effect of optical silica microsphere pressure sensors

NASA Astrophysics Data System (ADS)

Jiao, Xinbing; Hao, Ruirui; Pan, Qian; Zhao, Xinwei; Bai, Xue

2018-07-01

Two types of optical pressure sensors with silica microspheres are proposed. The size effect of optical silica microsphere pressure sensors is studied by using a single-wavelength laser beam and polarimeters. The silica microspheres with diameters of 1.0 μm, 1.5 μm and 2.0 μm are prepared on garnet substrates by a self-assembly method. The pressure and the optical properties of the silica microspheres are measured by a resistance strain sensor and Thorlabs Stokes polarimeters as a function of the external direct current (DC) voltage. The optical silica microsphere sensor in transmission mode is suitable for pressure measuring. The results show that the pressure increases, while the diameter of the silica microspheres decreases. The maximum internal pressure can reach up to 7.3 × 107 Pa when the diameter of the silica microspheres is 1.0 μm.

Internal performance of a nonaxisymmetric nozzle with a rotating upper flap and a center-pivoted lower flap

NASA Technical Reports Server (NTRS)

Wing, David J.; Leavitt, Laurence D.; Re, Richard J.

1993-01-01

An investigation was conducted at wind-off conditions in the static-test facility of the Langley 16-Foot Transonic Tunnel to determine the internal performance characteristics of a single expansion-ramp nozzle with thrust-vectoring capability to 105 degrees. Thrust vectoring was accomplished by the downward rotation of an upper flap with adaptive capability for internal contouring and a corresponding rotation of a center-pivoted lower flap. The static internal performance of configurations with pitch thrust-vector angles of 0 degrees, 60 degrees, and 105 degrees each with two throat areas, was investigated. The nozzle pressure ratio was varied from 1.5 to approximately 8.0 (5.0 for the maximum throat area configurations). Results of this study indicated that the nozzle configuration of the present investigation, when vectored, provided excellent flow-turning capability with relatively high levels of internal performance. In all cases, the thrust vector angle was a function of the nozzle pressure ratio. This result is expected because the flow is bounded by a single expansion surface on both vectored- and unvectored-nozzle geometries.

Orthotopic bladder substitution in men revisited: identification of continence predictors.

PubMed

Koraitim, M M; Atta, M A; Foda, M K

2006-11-01

We determined the impact of the functional characteristics of the neobladder and urethral sphincter on continence results, and determined the most significant predictors of continence. A total of 88 male patients 29 to 70 years old underwent orthotopic bladder substitution with tubularized ileocecal segment (40) and detubularized sigmoid (25) or ileum (23). Uroflowmetry, cystometry and urethral pressure profilometry were performed at 13 to 36 months (mean 19) postoperatively. The correlation between urinary continence and 28 urodynamic variables was assessed. Parameters that correlated significantly with continence were entered into a multivariate analysis using a logistic regression model to determine the most significant predictors of continence. Maximum urethral closure pressure was the only parameter that showed a statistically significant correlation with diurnal continence. Nocturnal continence had not only a statistically significant positive correlation with maximum urethral closure pressure, but also statistically significant negative correlations with maximum contraction amplitude, and baseline pressure at mid and maximum capacity. Three of these 4 parameters, including maximum urethral closure pressure, maximum contraction amplitude and baseline pressure at mid capacity, proved to be significant predictors of continence on multivariate analysis. While daytime continence is determined by maximum urethral closure pressure, during the night it is the net result of 2 forces that have about equal influence but in opposite directions, that is maximum urethral closure pressure vs maximum contraction amplitude plus baseline pressure at mid capacity. Two equations were derived from the logistic regression model to predict the probability of continence after orthotopic bladder substitution, including Z1 (diurnal) = 0.605 + 0.0085 maximum urethral closure pressure and Z2 (nocturnal) = 0.841 + 0.01 [maximum urethral closure pressure - (maximum contraction amplitude + baseline pressure at mid capacity)].

Development of multi-frequency ESR system for high-pressure measurements up to 2.5 GPa

NASA Astrophysics Data System (ADS)

Sakurai, T.; Fujimoto, K.; Matsui, R.; Kawasaki, K.; Okubo, S.; Ohta, H.; Matsubayashi, K.; Uwatoko, Y.; Tanaka, H.

2015-10-01

A new piston-cylinder pressure cell for electron spin resonance (ESR) has been developed. The pressure cell consists of a double-layer hybrid-type cylinder with internal components made of the ZrO2-based ceramics. It can generate a pressure of 2 GPa repeatedly and reaches a maximum pressure of around 2.5 GPa. A high-pressure ESR system using a cryogen-free superconducting magnet up 10 T has also been developed for this hybrid-type pressure cell. The frequency region is from 50 GHz to 400 GHz. This is the first time a pressure above 2 GPa has been achieved in multi-frequency ESR system using a piston-cylinder pressure cell. We demonstrate its potential by showing the results of the high-pressure ESR of the S = 1 system with the single ion anisotropy NiSnCl6 · 6H2O and the S = 1 / 2 quantum spin system CsCuCl3. We performed ESR measurements of these systems above 2 GPa successfully.

Calculation of Internal Pressures in the Fuel Tube of a Nuclear Reactor

NASA Technical Reports Server (NTRS)

Rosenbaum, B. M.; Allen, G.

1952-01-01

General procedures for computing internal pressures in fuel tubes of nuclear reactors are described and the effects on the pressure of varying neutron flux, fissioning material, and operating temperatures are discussed. A general proof is given that during pile operation each fission product is monotonically increasing and therefore a maximum amount of all elements is present at the time of shit down. The post-shutdown build-up of elements that are held in check during pile operation because of their inordinately high capture cross sections is calculated quantitatively. An account of chemical interactions between the many fission-product elements and the resulting effect on the total pressure completes the discussion. The general methods are illustrated by calculations applied to a system consisting of 90 percent enriched U235 in the form of UO2 packed into a hollow metal cylinder or "pin", operating at a flux of 8 x 10(exp 14) at 2000 F. Calculations of the pressure inside a pin are made with and without a sodium metal heat-transfer additive. The bulk of the pressure is shown to depend on the four elements, xenon, krypton, rubidium, and cesium; the amount of free oxygen, however, was also significant. For a shutdown time of 10(exp 6) seconds, the pressure was about 100 atmospheres.

Chest wall mobility is related to respiratory muscle strength and lung volumes in healthy subjects.

PubMed

Lanza, Fernanda de Cordoba; de Camargo, Anderson Alves; Archija, Lilian Rocha Ferraz; Selman, Jessyca Pachi Rodrigues; Malaguti, Carla; Dal Corso, Simone

2013-12-01

Chest wall mobility is often measured in clinical practice, but the correlations between chest wall mobility and respiratory muscle strength and lung volumes are unknown. We investigate the associations between chest wall mobility, axillary and thoracic cirtometry values, respiratory muscle strength (maximum inspiratory pressure and maximum expiratory pressure), and lung volumes (expiratory reserve volume, FEV(1), inspiratory capacity, FEV(1)/FVC), and the determinants of chest mobility in healthy subjects. In 64 healthy subjects we measured inspiratory capacity, FVC, FEV(1), expiratory reserve volume, maximum inspiratory pressure, and maximum expiratory pressure, and chest wall mobility via axillary and thoracic cirtometry. We used linear regression to evaluate the influence of the measured variables on chest wall mobility. The subjects' mean ± SD values were: age 24 ± 3 years, axillary cirtometry 6.3 ± 2.0 cm, thoracic cirtometry 7.5 ± 2.3 cm; maximum inspiratory pressure 90.4 ± 10.6% of predicted, maximum expiratory pressure 92.8 ± 13.5% of predicted, inspiratory capacity 99.7 ± 8.6% of predicted, FVC 101.9 ± 10.6% of predicted, FEV(1) 98.2 ± 10.3% of predicted, expiratory reserve volume 90.9 ± 19.9% of predicted. There were significant correlations between axillary cirtometry and FVC (r = 0.32), FEV(1) (r = 0.30), maximum inspiratory pressure (r = 0.48), maximum expiratory pressure (r = 0.25), and inspiratory capacity (r = 0.24), and between thoracic cirtometry and FVC (r = 0.50), FEV(1) (r = 0.48), maximum inspiratory pressure (r = 0.46), maximum expiratory pressure (r = 0.37), inspiratory capacity (r = 0.39), and expiratory reserve volume (r = 0.47). In multiple regression analysis the variable that best explained the axillary cirtometry variation was maximum inspiratory pressure (R(2) 0.23), and for thoracic cirtometry it was FVC and maximum inspiratory pressure (R(2) 0.32). Chest mobility in healthy subjects is related to respiratory muscle strength and lung function; the higher the axillary cirtometry and thoracic cirtometry values, the greater the maximum inspiratory pressure, maximum expiratory pressure, and lung volumes in healthy subjects.

Simulation of Cooling and Pressure Effects on Inflated Pahoehoe Lava Flows

NASA Technical Reports Server (NTRS)

Glaze, Lori S.; Baloga, Stephen M.

2016-01-01

Pahoehoe lobes are often emplaced by the advance of discrete toes accompanied by inflation of the lobe surface. Many random effects complicate modeling lobe emplacement, such as the location and orientation of toe breakouts, their dimensions, mechanical strength of the crust, micro-topography and a host of other factors. Models that treat the movement of lava parcels as a random walk have explained some of the overall features of emplacement. However, cooling of the surface and internal pressurization of the fluid interior has not been modeled. This work reports lobe simulations that explicitly incorporate 1) cooling of surface lava parcels, 2) the propensity of breakouts to occur at warmer margins that are mechanically weaker than cooler ones, and 3) the influence of internal pressurization associated with inflation. The surface temperature is interpreted as a surrogate for the mechanic strength of the crust at each location and is used to determine the probability of a lava parcel transfer from that location. When only surface temperature is considered, the morphology and dimensions of simulated lobes are indistinguishable from equiprobable simulations. However, inflation within a lobe transmits pressure to all connected fluid locations with the warmer margins being most susceptible to breakouts and expansion. Simulations accounting for internal pressurization feature morphologies and dimensions that are dramatically different from the equiprobable and temperature-dependent models. Even on flat subsurfaces the pressure-dependent model produces elongate lobes with distinct directionality. Observables such as topographic profiles, aspect ratios, and maximum extents should be readily distinguishable in the field.

Anorectal motility abnormalities in children with encopresis and chronic constipation.

PubMed

Raghunath, Neeraj; Glassman, Mark S; Halata, Michael S; Berezin, Stuart H; Stewart, Julian M; Medow, Marvin S

2011-02-01

To evaluate the response to rectal distension in children with chronic constipation and children with chronic constipation and encopresis. We studied 27 children, aged 3 to 16 years, with chronic constipation; 12 had encopresis. Anorectal motility was measured with a solid state catheter. When the catheter was located in the internal sphincter, the balloon was inflated to 60 mL with air. There were no differences in age, sex distribution, and duration of constipation in the two groups. Comparing groups, anorectal manometry showed no differences in the resting sphincter pressure, recovery pressure, the lowest relaxation pressure, and percent relaxation. However, time to maximum relaxation, time to recovery to baseline pressure, and duration of relaxation were significantly higher in patients with constipation and encopresis, compared with patients who had constipation alone. There may be an imbalance in neuromuscular control of defecation in constipated patients with encopresis that results in incontinence as a consequence of the increased time to recovery and duration of relaxation of the internal anal sphincter. Copyright © 2011 Mosby, Inc. All rights reserved.

Simulation and evaluation of rupturable coated capsules by finite element method.

PubMed

Yang, Yan; Fang, Jie; Shen, Lian; Shan, Weiguang

2017-03-15

The objective of this study was to simulate and evaluate the burst behavior of rupturable coated capsules by finite element method (FEM). Film and coated capsules were prepared by dip-coating method and their dimensions were determined by stereomicroscope. Mechanical properties of the film were measured by tensile test and used as material properties of FEM models. Swelling pressure was determined by restrained expansion method and applied to the internal surface of FEM models. Water uptake of coated capsules was determined to study the formation of internal pressure. Burst test and in vitro dissolution was used to verify the FEM models, which were used to study and predict the coating burst behavior. Simulated results of coating burst behavior were well agreed with the experiment results. Swelling pressure, material properties and dimensions of coating had influence on the maximum stress. Burst pressure and critical L-HPC content were calculated for burst prediction and formulation optimization. FEM simulation was a feasible way to simulate and evaluate the burst behavior of coated capsules. Copyright © 2017 Elsevier B.V. All rights reserved.

Development of fused slurry silicide coatings for tantalum reentry heat shields

NASA Technical Reports Server (NTRS)

Warnock, R. V.; Stetson, A. R.

1972-01-01

A fused slurry silicide coating was developed to provide atmospheric reentry protection for the 90Ta-lOW alloy. Overlaying the silicide with a highly refractory glass greatly improved total lifetime and reliability of the coating system. Low pressure, slow cycle lifetimes in excess of 100 cycles were consistently recorded for 1700 K - 13 and 1300 N/sq m test conditions. A minimum of 25 cycles was obtained for 1810 K - 1300 N/sq m conditions. About 50 simulated reentry cycles (variable temperature, pressure, and stress) were endured by coated 1-inch miniature heat shield panels when exposed to a maximum of 1700 K and either internal or external pressure conditions.

Time-dependent response of filamentary composite spherical pressure vessels

NASA Technical Reports Server (NTRS)

Dozier, J. D.

1983-01-01

A filamentary composite spherical pressure vessel is modeled as a pseudoisotropic (or transversely isotropic) composite shell, with the effects of the liner and fill tubes omitted. Equations of elasticity, macromechanical and micromechanical formulations, and laminate properties are derived for the application of an internally pressured spherical composite vessel. Viscoelastic properties for the composite matrix are used to characterize time-dependent behavior. Using the maximum strain theory of failure, burst pressure and critical strain equations are formulated, solved in the Laplace domain with an associated elastic solution, and inverted back into the time domain using the method of collocation. Viscoelastic properties of HBFR-55 resin are experimentally determined and a Kevlar/HBFR-55 system is evaluated with a FORTRAN program. The computed reduction in burst pressure with respect to time indicates that the analysis employed may be used to predict the time-dependent response of a filamentary composite spherical pressure vessel.

Pressure Dependence of the Peierls Stress in Aluminum

NASA Astrophysics Data System (ADS)

Dang, Khanh; Spearot, Douglas

2018-03-01

The effect of pressure applied normal to the {111} slip plane on the Peierls stress in Al is studied via atomistic simulations. Edge, screw, 30°, and 60° straight dislocations are created using the Volterra displacement fields for isotropic elasticity. For each dislocation character angle, the Peierls stress is calculated based on the change in the internal energy, which is an invariant measure of the dislocation driving force. It is found that the Peierls stress for dislocations under zero pressure is in general agreement with previous results. For screw and 60° dislocations, the Peierls stress versus pressure relationship has maximum values associated with stacking fault widths that are multiples of the Peierls period. For the edge dislocation, the Peierls stress decreases with increasing pressure from tension to compression. Compared with the Mendelev potential, the Peierls stress calculated from the Mishin potential is more sensitive to changes in pressure.

Moissanite anvil cell design for Giga-Pascal nuclear magnetic resonance.

PubMed

Meier, Thomas; Herzig, Tobias; Haase, Jürgen

2014-04-01

A new design of a non-magnetic high-pressure anvil cell for nuclear magnetic resonance (NMR) experiments at Giga-Pascal pressures is presented, which uses a micro-coil inside the pressurized region for high-sensitivity NMR. The comparably small cell has a length of 22 mm and a diameter of 18 mm, so it can be used with most NMR magnets. The performance of the cell is demonstrated with external-force vs. internal-pressure experiments, and the cell is shown to perform well at pressures up to 23.5 GPa using 800 μm 6H-SiC large cone Boehler-type anvils. (1)H, (23)Na, (27)Al, (69)Ga, and (71)Ga NMR test measurements are presented, which show a resolution of better than 4.5 ppm, and an almost maximum possible signal-to-noise ratio.

Automatic Blood Pressure Measurements During Exercise

NASA Technical Reports Server (NTRS)

Weaver, Charles S.

1985-01-01

Microprocessor circuits and a computer algorithm for automatically measuring blood pressure during ambulatory monitoring and exercise stress testing have been under development at SRI International. A system that records ECG, Korotkov sound, and arm cuff pressure for off-line calculation of blood pressure has been delivered to NASA, and an LSLE physiological monitoring system that performs the algorithm calculations in real-time is being constructed. The algorithm measures the time between the R-wave peaks and the corresponding Korotkov sound on-set (RK-interval). Since the curve of RK-interval versus cuff pressure during deflation is predictable and slowly varying, windows can be set around the curve to eliminate false Korotkov sound detections that result from noise. The slope of this curve, which will generally decrease during exercise, is the inverse of the systolic slope of the brachial artery pulse. In measurements taken during treadmill stress testing, the changes in slopes of subjects with coronary artery disease were markedly different from the changes in slopes of healthy subjects. Measurements of slope and O2 consumption were also made before and after ten days of bed rest during NASA/Ames Research Center bed rest studies. Typically, the maximum rate of O2 consumption during the post-bed rest test is less than the maximum rate during the pre-bed rest test. The post-bed rest slope changes differ from the pre-bed rest slope changes, and the differences are highly correlated with the drop in the maximum rate of O2 consumption. We speculate that the differences between pre- and post-bed rest slopes are due to a drop in heart contractility.

Abandoned coal mine stores gas for Colorado peak-day demands

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

Brown, L.W.

1978-09-01

Since 1961, the Leyden Mine, from which 6 million tons of coal had been removed to leave a 150 million cu ft void, has been used for gas storage at 250 psig max pressure, after the hoisting and ventilation shafts had been sealed with concrete, rock, sand, and mud. Following several withdrawal expansions, a design for maximum delivery of 230 million cu ft/day for five days with a pressure drop in the cavern down to 100 psig was developed to satisfy customer requirements for peak shaving. This required redesigning the gathering system by looping large existing lines, eliminating inefficient ones,more » and drilling additional wells; installing three lightweight 3500-hp Centaur turbine/compressor units from Solar Turbines International to provide the minimum 200 psig compressor discharge pressure needed for gas distribution on peak usage days; and installing Donaldson Co. engine air-inlet silencers on the turbine inlets to reduce noise levels below the public code requirement. In the 1977-78 heating season, the Leyden facility produced 196 million cu ft/day of gas; with continued load growth and well drilling to reduce pressure loss, the maximum design flow rate will be attained.« less

49 CFR 192.619 - Maximum allowable operating pressure: Steel or plastic pipelines.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 49 Transportation 3 2013-10-01 2013-10-01 false Maximum allowable operating pressure: Steel or... Operations § 192.619 Maximum allowable operating pressure: Steel or plastic pipelines. (a) No person may operate a segment of steel or plastic pipeline at a pressure that exceeds a maximum allowable operating...

49 CFR 192.619 - Maximum allowable operating pressure: Steel or plastic pipelines.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 49 Transportation 3 2011-10-01 2011-10-01 false Maximum allowable operating pressure: Steel or... Operations § 192.619 Maximum allowable operating pressure: Steel or plastic pipelines. (a) No person may operate a segment of steel or plastic pipeline at a pressure that exceeds a maximum allowable operating...

49 CFR 192.619 - Maximum allowable operating pressure: Steel or plastic pipelines.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 49 Transportation 3 2012-10-01 2012-10-01 false Maximum allowable operating pressure: Steel or... Operations § 192.619 Maximum allowable operating pressure: Steel or plastic pipelines. (a) No person may operate a segment of steel or plastic pipeline at a pressure that exceeds a maximum allowable operating...

49 CFR 192.619 - Maximum allowable operating pressure: Steel or plastic pipelines.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 49 Transportation 3 2014-10-01 2014-10-01 false Maximum allowable operating pressure: Steel or... Operations § 192.619 Maximum allowable operating pressure: Steel or plastic pipelines. (a) No person may operate a segment of steel or plastic pipeline at a pressure that exceeds a maximum allowable operating...

Maximum static inspiratory and expiratory pressures with different lung volumes

PubMed Central

Lausted, Christopher G; Johnson, Arthur T; Scott, William H; Johnson, Monique M; Coyne, Karen M; Coursey, Derya C

2006-01-01

Background Maximum pressures developed by the respiratory muscles can indicate the health of the respiratory system, help to determine maximum respiratory flow rates, and contribute to respiratory power development. Past measurements of maximum pressures have been found to be inadequate for inclusion in some exercise models involving respiration. Methods Maximum inspiratory and expiratory airway pressures were measured over a range of lung volumes in 29 female and 19 male adults. A commercial bell spirometry system was programmed to occlude airflow at nine target lung volumes ranging from 10% to 90% of vital capacity. Results In women, maximum expiratory pressure increased with volume from 39 to 61 cmH2O and maximum inspiratory pressure decreased with volume from 66 to 28 cmH2O. In men, maximum expiratory pressure increased with volume from 63 to 97 cmH2O and maximum inspiratory pressure decreased with volume from 97 to 39 cmH2O. Equations describing pressures for both sexes are: Pe/Pmax = 0.1426 Ln( %VC) + 0.3402 R2 = 0.95 Pi/Pmax = 0.234 Ln(100 - %VC) - 0.0828 R2 = 0.96 Conclusion These results were found to be consistent with values and trends obtained by other authors. Regression equations may be suitable for respiratory mechanics models. PMID:16677384

Maximum home blood pressure is a useful indicator of diabetic nephropathy in patients with type 2 diabetes mellitus: KAMOGAWA-HBP study.

PubMed

Oyabu, Chikako; Ushigome, Emi; Matsumoto, Shinobu; Tanaka, Toru; Hasegawa, Goji; Nakamura, Naoto; Ohnishi, Masayoshi; Tsunoda, Sei; Ushigome, Hidetaka; Yokota, Isao; Tanaka, Muhei; Asano, Mai; Yamazaki, Masahiro; Fukui, Michiaki

2017-11-01

Maximum home systolic blood pressure has been shown to predict target organ damage. We aimed to clarify the association between maximum home systolic blood pressure and urine albumin to creatinine ratio, an indicator of early-phase diabetic nephropathy in patients with type 2 diabetes. In 1040 patients, we assessed the relationship of mean or maximum home systolic blood pressure and urine albumin to creatinine ratio, and compared the area under the receiver operating characteristic curve of mean or maximum home systolic blood pressure for diabetic nephropathy (urine albumin to creatinine ratio ⩾30 mg/g Cr). Multivariate linear regression analyses indicated that mean morning systolic blood pressure ( β = 0.010, p < 0.001) and maximum morning systolic blood pressure ( β = 0.008, p < 0.001) were significantly associated with urine albumin to creatinine ratio. Area under the receiver operating characteristic curve (95% confidence interval) for diabetic nephropathy in mean and maximum morning systolic blood pressure was 0.667 (0.634-0.700; p < 0.001) and 0.671 (0.638-0.703; p < 0.001), respectively. Maximum home systolic blood pressure, as well as mean home systolic blood pressure, was significantly associated with diabetic nephropathy in patients with type 2 diabetes.

Laser-excited optical emission response of CdTe quantum dot/polymer nanocomposite under shock compression

NASA Astrophysics Data System (ADS)

Xiao, Pan; Kang, Zhitao; Bansihev, Alexandr A.; Breidenich, Jennifer; Scripka, David A.; Christensen, James M.; Summers, Christopher J.; Dlott, Dana D.; Thadhani, Naresh N.; Zhou, Min

2016-01-01

Laser-driven shock compression experiments and corresponding finite element method simulations are carried out to investigate the blueshift in the optical emission spectra under continuous laser excitation of a dilute composite consisting of 0.15% CdTe quantum dots by weight embedded in polyvinyl alcohol polymer. This material is a potential candidate for use as internal stress sensors. The analyses focus on the time histories of the wavelength blue-shift for shock loading with pressures up to 7.3 GPa. The combined measurements and calculations allow a relation between the wavelength blueshift and pressure for the loading conditions to be extracted. It is found that the blueshift first increases with pressure to a maximum and subsequently decreases with pressure. This trend is different from the monotonic increase of blueshift with pressure observed under conditions of quasistatic hydrostatic compression. Additionally, the blueshift in the shock experiments is much smaller than that in hydrostatic experiments at the same pressure levels. The differences in responses are attributed to the different stress states achieved in the shock and hydrostatic experiments and the time dependence of the mechanical response of the polymer in the composite. The findings offer a potential guide for the design and development of materials for internal stress sensors for shock conditions.

[The association between blood pressure variability and sleep stability in essential hypertensive patients with sleep disorder].

PubMed

Zhu, Y Q; Long, Q; Xiao, Q F; Zhang, M; Wei, Y L; Jiang, H; Tang, B

2018-03-13

Objective: To investigate the association of blood pressure variability and sleep stability in essential hypertensive patients with sleep disorder by cardiopulmonary coupling. Methods: Performed according to strict inclusion and exclusion criteria, 88 new cases of essential hypertension who came from the international department and the cardiology department of china-japan friendship hospital were enrolled. Sleep stability and 24 h ambulatory blood pressure data were collected by the portable sleep monitor based on cardiopulmonary coupling technique and 24 h ambulatory blood pressure monitor. Analysis the correlation of blood pressure variability and sleep stability. Results: In the nighttime, systolic blood pressure standard deviation, systolic blood pressure variation coefficient, the ratio of the systolic blood pressure minimum to the maximum, diastolic blood pressure standard deviation, diastolic blood pressure variation coefficient were positively correlated with unstable sleep duration ( r =0.185, 0.24, 0.237, 0.43, 0.276, P <0.05). Conclusions: Blood pressure variability is associated with sleep stability, especially at night, the longer the unstable sleep duration, the greater the variability in night blood pressure.

CFD Modelling of Bore Erosion in Two-Stage Light Gas Guns

NASA Technical Reports Server (NTRS)

Bogdanoff, D. W.

1998-01-01

A well-validated quasi-one-dimensional computational fluid dynamics (CFD) code for the analysis of the internal ballistics of two-stage light gas guns is modified to explicitly calculate the ablation of steel from the gun bore and the incorporation of the ablated wall material into the hydrogen working cas. The modified code is used to model 45 shots made with the NASA Ames 0.5 inch light gas gun over an extremely wide variety of gun operating conditions. Good agreement is found between the experimental and theoretical piston velocities (maximum errors of +/-2% to +/-6%) and maximum powder pressures (maximum errors of +/-10% with good igniters). Overall, the agreement between the experimental and numerically calculated gun erosion values (within a factor of 2) was judged to be reasonably good, considering the complexity of the processes modelled. Experimental muzzle velocities agree very well (maximum errors of 0.5-0.7 km/sec) with theoretical muzzle velocities calculated with loading of the hydrogen gas with the ablated barrel wall material. Comparison of results for pump tube volumes of 100%, 60% and 40% of an initial benchmark value show that, at the higher muzzle velocities, operation at 40% pump tube volume produces much lower hydrogen loading and gun erosion and substantially lower maximum pressures in the gun. Large muzzle velocity gains (2.4-5.4 km/sec) are predicted upon driving the gun harder (that is, upon using, higher powder loads and/or lower hydrogen fill pressures) when hydrogen loading is neglected; much smaller muzzle velocity gains (1.1-2.2 km/sec) are predicted when hydrogen loading is taken into account. These smaller predicted velocity gains agree well with those achieved in practice. CFD snapshots of the hydrogen mass fraction, density and pressure of the in-bore medium are presented for a very erosive shot.

46 CFR 54.10-5 - Maximum allowable working pressure (reproduces UG-98).

Code of Federal Regulations, 2013 CFR

2013-10-01

... 46 Shipping 2 2013-10-01 2013-10-01 false Maximum allowable working pressure (reproduces UG-98). 54.10-5 Section 54.10-5 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING PRESSURE VESSELS Inspection, Reports, and Stamping § 54.10-5 Maximum allowable working pressure (reproduces UG-98). (a) The maximum allowable...

46 CFR 54.10-5 - Maximum allowable working pressure (reproduces UG-98).

Code of Federal Regulations, 2011 CFR

2011-10-01

... 46 Shipping 2 2011-10-01 2011-10-01 false Maximum allowable working pressure (reproduces UG-98). 54.10-5 Section 54.10-5 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING PRESSURE VESSELS Inspection, Reports, and Stamping § 54.10-5 Maximum allowable working pressure (reproduces UG-98). (a) The maximum allowable...

46 CFR 54.10-5 - Maximum allowable working pressure (reproduces UG-98).

Code of Federal Regulations, 2014 CFR

2014-10-01

... 46 Shipping 2 2014-10-01 2014-10-01 false Maximum allowable working pressure (reproduces UG-98). 54.10-5 Section 54.10-5 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING PRESSURE VESSELS Inspection, Reports, and Stamping § 54.10-5 Maximum allowable working pressure (reproduces UG-98). (a) The maximum allowable...

46 CFR 54.10-5 - Maximum allowable working pressure (reproduces UG-98).

Code of Federal Regulations, 2012 CFR

2012-10-01

... 46 Shipping 2 2012-10-01 2012-10-01 false Maximum allowable working pressure (reproduces UG-98). 54.10-5 Section 54.10-5 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING PRESSURE VESSELS Inspection, Reports, and Stamping § 54.10-5 Maximum allowable working pressure (reproduces UG-98). (a) The maximum allowable...

International urodynamic basic spinal cord injury data set.

PubMed

Biering-Sørensen, F; Craggs, M; Kennelly, M; Schick, E; Wyndaele, J-J

2008-07-01

To create the International Urodynamic Basic Spinal Cord Injury (SCI) Data Set within the framework of the International SCI Data Sets. International working group. The draft of the data set was developed by a working group consisting of members appointed by the Neurourology Committee of the International Continence Society, the European Association of Urology, the American Spinal Injury Association (ASIA), the International Spinal Cord Society (ISCoS) and a representative of the Executive Committee of the International SCI Standards and Data Sets. The final version of the data set was developed after review and comments by members of the Executive Committee of the International SCI Standards and Data Sets, the ISCoS Scientific Committee, ASIA Board, relevant and interested (international) organizations and societies (around 40) and persons and the ISCoS Council. Endorsement of the data set by relevant organizations and societies will be obtained. To make the data set uniform, each variable and each response category within each variable have been specifically defined in a way that is designed to promote the collection and reporting of comparable minimal data. Variables included in the International Urodynamic Basic SCI Data Set are date of data collection, bladder sensation during filling cystometry, detrusor function, compliance during filing cystometry, function during voiding, detrusor leak point pressure, maximum detrusor pressure, cystometric bladder capacity and post-void residual volume.

Moissanite anvil cell design for giga-pascal nuclear magnetic resonance

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

Meier, Thomas; Herzig, Tobias; Haase, Jürgen

2014-04-15

A new design of a non-magnetic high-pressure anvil cell for nuclear magnetic resonance (NMR) experiments at Giga-Pascal pressures is presented, which uses a micro-coil inside the pressurized region for high-sensitivity NMR. The comparably small cell has a length of 22 mm and a diameter of 18 mm, so it can be used with most NMR magnets. The performance of the cell is demonstrated with external-force vs. internal-pressure experiments, and the cell is shown to perform well at pressures up to 23.5 GPa using 800 μm 6H-SiC large cone Boehler-type anvils. {sup 1}H, {sup 23}Na, {sup 27}Al, {sup 69}Ga, and {supmore » 71}Ga NMR test measurements are presented, which show a resolution of better than 4.5 ppm, and an almost maximum possible signal-to-noise ratio.« less

A method to directly measure maximum volume of fish stomachs or digestive tracts

USGS Publications Warehouse

Burley, C.C.; Vigg, S.

1989-01-01

A new method for measuring maximum stomach or digestive tract volume of fish incorporates air injection at constant pressure with water displacement to measure directly the internal volume of a stomach or analogous structure. The method was tested with coho salmon, Oncorhynchus kisutch (Walbaum), which has a true stomach, and northern squawfish, Ptychocheilus oregonensis(Richardson), which has a modified foregut as a functional analogue. Both species were collected during July-October 1987 from the Columbia River, U.S.A. Relationships between fish weight (= volume) and maximum volume of the digestive organ were best fitted for coho salmon by an allometric model and for northern squawfish by an exponential model. Least squares regression analysis of individual measurements showed less variability in the volume of coho salmon stomachs (R2= 0.85) than in the total digestive tracts (R2= 0.55) and foreguts (R2= 0.61) of northern squawfish, relative to fish size. Compared to previous methods, the new technique has the advantage of accurately measuring the internal volume of a wide range of digestive organ shapes and sizes.

Interlabial contact pressures exhibited in dysarthria following traumatic brain injury during speech and nonspeech tasks.

PubMed

Goozée, Justine V; Murdoch, Bruce E; Theodoros, Deborah G

2002-01-01

A miniature pressure transducer was used to assess the interlabial contact pressures produced by a group of 19 adults (mean age 30.6 years) with dysarthria following severe traumatic brain injury (TBI) during a set of speech and nonspeech tasks. Ten parameters relating to lip strength, endurance, rate of movement and lip pressure accuracy and stability were measured from the nonspeech tasks. The results attained by the TBI group were compared against a group of 19 age- and sex-matched control subjects. Significant differences between the groups were found for maximum interlabial contact pressure, maximum rate of repetition of maximum pressure, and lip pressure accuracy at 50 and 10% levels of maximum pressure. In regards to speech, the interlabial contact pressures generated by the TBI group and control group did not differ significantly. When expressed as percentages of maximum pressure, however, the TBI group's interlabial pressures appeared to have been generated with greater physiological effort. Copyright 2002 S. Karger AG, Basel

One-Dimensional Modelling of Internal Ballistics

NASA Astrophysics Data System (ADS)

Monreal-González, G.; Otón-Martínez, R. A.; Velasco, F. J. S.; García-Cascáles, J. R.; Ramírez-Fernández, F. J.

2017-10-01

A one-dimensional model is introduced in this paper for problems of internal ballistics involving solid propellant combustion. First, the work presents the physical approach and equations adopted. Closure relationships accounting for the physical phenomena taking place during combustion (interfacial friction, interfacial heat transfer, combustion) are deeply discussed. Secondly, the numerical method proposed is presented. Finally, numerical results provided by this code (UXGun) are compared with results of experimental tests and with the outcome from a well-known zero-dimensional code. The model provides successful results in firing tests of artillery guns, predicting with good accuracy the maximum pressure in the chamber and muzzle velocity what highlights its capabilities as prediction/design tool for internal ballistics.

Development of multi-frequency ESR system for high-pressure measurements up to 2.5 GPa.

PubMed

Sakurai, T; Fujimoto, K; Matsui, R; Kawasaki, K; Okubo, S; Ohta, H; Matsubayashi, K; Uwatoko, Y; Tanaka, H

2015-10-01

A new piston-cylinder pressure cell for electron spin resonance (ESR) has been developed. The pressure cell consists of a double-layer hybrid-type cylinder with internal components made of the ZrO2-based ceramics. It can generate a pressure of 2 GPa repeatedly and reaches a maximum pressure of around 2.5 GPa. A high-pressure ESR system using a cryogen-free superconducting magnet up 10T has also been developed for this hybrid-type pressure cell. The frequency region is from 50 GHz to 400 GHz. This is the first time a pressure above 2 GPa has been achieved in multi-frequency ESR system using a piston-cylinder pressure cell. We demonstrate its potential by showing the results of the high-pressure ESR of the S=1 system with the single ion anisotropy NiSnCl6·6H2O and the S=1/2 quantum spin system CsCuCl3. We performed ESR measurements of these systems above 2 GPa successfully. Copyright © 2015 Elsevier Inc. All rights reserved.

An Assessment of Helium Evolution from Helium-Saturated Propellant Depressurization in Space

NASA Technical Reports Server (NTRS)

Nguyen, Bich N.; Best, Frederick; Wong, Tony; Kurwitz, Cable; McConnaughey, H. (Technical Monitor)

2001-01-01

Helium evolution from the transfer of helium-saturated propellant in space is quantified to assess its impacts from creating two-phase gas/liquid flow from the supply tank, gas injection into the receiving tank, and liquid discharge from the receiving tank. Propellant transfer takes place between two similar tanks whose maximum storage capacity is approximately 2.55 cubic meters each. The maximum on-orbit propellants transfer capability is 9000 lbm (fuel and oxidizer). The transfer line is approximately 1.27 cm in diameter and 6096 cm in length and comprised of the fluid interconnect system (FICS), the orbiter propellant transfer system (OPTS), and the International Space Station (ISS) propulsion module (ISSPM). The propellant transfer rate begins at approximately 11 liter per minute (lpm) and subsequently drops to approximately 0.5 lpm. The tank nominal operating pressure is approximately 1827 kPa (absolute). The line pressure drops for Monomethy1hydrazine (MMH) and Nitrogen tetroxide (NTO) at 11.3 lpm are approximately 202 kPa and 302 kPa, respectively. The pressure-drop results are based on a single-phase flow. The receiving tank is required to vent from approximately 1827 kPa to a lower pressure to affect propellant transfer. These pressure-drop scenarios cause the helium-saturated propellants to release excess helium. For tank ullage venting, the maximum volumes of helium evolved at tank pressure are approximately 0.5 ft3 for MMH and 2 ft3 for NTO. In microgravity environment, due to lack of body force, the helium evolution from a liquid body acts to propel it, which influences its fluid dynamics. For propellant transfer, the volume fractions of helium evolved at line pressure are 0.1% by volume for MMH and 0.6 % by volume for NTO at 11.3 lpm. The void fraction of helium evolved varies as an approximate second order power function of flow rate.

Influence of bronchial diameter change on the airflow dynamics based on a pressure-controlled ventilation system.

PubMed

Ren, Shuai; Cai, Maolin; Shi, Yan; Xu, Weiqing; Zhang, Xiaohua Douglas

2018-03-01

Bronchial diameter is a key parameter that affects the respiratory treatment of mechanically ventilated patients. In this paper, to reveal the influence of bronchial diameter on the airflow dynamics of pressure-controlled mechanically ventilated patients, a new respiratory system model is presented that combines multigeneration airways with lungs. Furthermore, experiments and simulation studies to verify the model are performed. Finally, through the simulation study, it can be determined that in airway generations 2 to 7, when the diameter is reduced to half of the original value, the maximum air pressure (maximum air pressure in lungs) decreases by nearly 16%, the maximum flow decreases by nearly 30%, and the total airway pressure loss (sum of each generation pressure drop) is more than 5 times the original value. Moreover, in airway generations 8 to 16, with increasing diameter, the maximum air pressure, maximum flow, and total airway pressure loss remain almost constant. When the diameter is reduced to half of the original value, the maximum air pressure decreases by 3%, the maximum flow decreases by nearly 5%, and the total airway pressure loss increases by 200%. The study creates a foundation for improvement in respiratory disease diagnosis and treatment. Copyright © 2017 John Wiley & Sons, Ltd.

Temperature and pressure influence on maximum rates of pressure rise during explosions of propane-air mixtures in a spherical vessel.

PubMed

Razus, D; Brinzea, V; Mitu, M; Movileanu, C; Oancea, D

2011-06-15

The maximum rates of pressure rise during closed vessel explosions of propane-air mixtures are reported, for systems with various initial concentrations, pressures and temperatures ([C(3)H(8)]=2.50-6.20 vol.%, p(0)=0.3-1.3 bar; T(0)=298-423 K). Experiments were performed in a spherical vessel (Φ=10 cm) with central ignition. The deflagration (severity) index K(G), calculated from experimental values of maximum rates of pressure rise is examined against the adiabatic deflagration index, K(G, ad), computed from normal burning velocities and peak explosion pressures. At constant temperature and fuel/oxygen ratio, both the maximum rates of pressure rise and the deflagration indices are linear functions of total initial pressure, as reported for other fuel-air mixtures. At constant initial pressure and composition, the maximum rates of pressure rise and deflagration indices are slightly influenced by the initial temperature; some influence of the initial temperature on maximum rates of pressure rise is observed only for propane-air mixtures far from stoichiometric composition. The differentiated temperature influence on the normal burning velocities and the peak explosion pressures might explain this behaviour. Copyright © 2011 Elsevier B.V. All rights reserved.

49 CFR 195.406 - Maximum operating pressure.

Code of Federal Regulations, 2010 CFR

2010-10-01

... HAZARDOUS LIQUIDS BY PIPELINE Operation and Maintenance § 195.406 Maximum operating pressure. (a) Except for surge pressures and other variations from normal operations, no operator may operate a pipeline at a... 49 Transportation 3 2010-10-01 2010-10-01 false Maximum operating pressure. 195.406 Section 195...

49 CFR 195.406 - Maximum operating pressure.

Code of Federal Regulations, 2012 CFR

2012-10-01

... HAZARDOUS LIQUIDS BY PIPELINE Operation and Maintenance § 195.406 Maximum operating pressure. (a) Except for surge pressures and other variations from normal operations, no operator may operate a pipeline at a... 49 Transportation 3 2012-10-01 2012-10-01 false Maximum operating pressure. 195.406 Section 195...

49 CFR 195.406 - Maximum operating pressure.

Code of Federal Regulations, 2014 CFR

2014-10-01

... HAZARDOUS LIQUIDS BY PIPELINE Operation and Maintenance § 195.406 Maximum operating pressure. (a) Except for surge pressures and other variations from normal operations, no operator may operate a pipeline at a... 49 Transportation 3 2014-10-01 2014-10-01 false Maximum operating pressure. 195.406 Section 195...

49 CFR 195.406 - Maximum operating pressure.

Code of Federal Regulations, 2011 CFR

2011-10-01

... HAZARDOUS LIQUIDS BY PIPELINE Operation and Maintenance § 195.406 Maximum operating pressure. (a) Except for surge pressures and other variations from normal operations, no operator may operate a pipeline at a... 49 Transportation 3 2011-10-01 2011-10-01 false Maximum operating pressure. 195.406 Section 195...

49 CFR 195.406 - Maximum operating pressure.

Code of Federal Regulations, 2013 CFR

2013-10-01

... HAZARDOUS LIQUIDS BY PIPELINE Operation and Maintenance § 195.406 Maximum operating pressure. (a) Except for surge pressures and other variations from normal operations, no operator may operate a pipeline at a... 49 Transportation 3 2013-10-01 2013-10-01 false Maximum operating pressure. 195.406 Section 195...

46 CFR 151.03-37 - Maximum allowable working pressure.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 46 Shipping 5 2013-10-01 2013-10-01 false Maximum allowable working pressure. 151.03-37 Section 151.03-37 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CERTAIN BULK DANGEROUS CARGOES BARGES CARRYING BULK LIQUID HAZARDOUS MATERIAL CARGOES Definitions § 151.03-37 Maximum allowable working pressure. The maximum allowable working...

46 CFR 151.03-37 - Maximum allowable working pressure.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 46 Shipping 5 2012-10-01 2012-10-01 false Maximum allowable working pressure. 151.03-37 Section 151.03-37 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CERTAIN BULK DANGEROUS CARGOES BARGES CARRYING BULK LIQUID HAZARDOUS MATERIAL CARGOES Definitions § 151.03-37 Maximum allowable working pressure. The maximum allowable working...

46 CFR 151.03-37 - Maximum allowable working pressure.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 46 Shipping 5 2011-10-01 2011-10-01 false Maximum allowable working pressure. 151.03-37 Section 151.03-37 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CERTAIN BULK DANGEROUS CARGOES BARGES CARRYING BULK LIQUID HAZARDOUS MATERIAL CARGOES Definitions § 151.03-37 Maximum allowable working pressure. The maximum allowable working...

46 CFR 151.03-37 - Maximum allowable working pressure.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 5 2010-10-01 2010-10-01 false Maximum allowable working pressure. 151.03-37 Section 151.03-37 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CERTAIN BULK DANGEROUS CARGOES BARGES CARRYING BULK LIQUID HAZARDOUS MATERIAL CARGOES Definitions § 151.03-37 Maximum allowable working pressure. The maximum allowable working...

46 CFR 151.03-37 - Maximum allowable working pressure.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 46 Shipping 5 2014-10-01 2014-10-01 false Maximum allowable working pressure. 151.03-37 Section 151.03-37 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CERTAIN BULK DANGEROUS CARGOES BARGES CARRYING BULK LIQUID HAZARDOUS MATERIAL CARGOES Definitions § 151.03-37 Maximum allowable working pressure. The maximum allowable working...

Review of invasive urodynamics and progress towards non-invasive measurements in the assessment of bladder outlet obstruction

PubMed Central

Griffiths, C. J.; Pickard, R. S.

2009-01-01

Objective: This article defines the need for objective measurements to help diagnose the cause of lower urinary tract symptoms (LUTS). It describes the conventional techniques available, mainly invasive, and then summarizes the emerging range of non-invasive measurement techniques. Methods: This is a narrative review derived form the clinical and scientific knowledge of the authors together with consideration of selected literature. Results: Consideration of measured bladder pressure urinary flow rate during voiding in an invasive pressure flow study is considered the gold standard for categorization of bladder outlet obstruction (BOO). The diagnosis is currently made by plotting the detrusor pressure at maximum flow (pdetQmax) and maximum flow rate (Qmax) on the nomogram approved by the International Continence Society. This plot will categorize the void as obstructed, equivocal or unobstructed. The invasive and relatively complex nature of this investigation has led to a number of inventive techniques to categorize BOO either by measuring bladder pressure non-invasively or by providing a proxy measure such as bladder weight. Conclusion: Non-invasive methods of diagnosing BOO show great promise and a few have reached the stage of being commercially available. Further studies are however needed to validate the measurement technique and assess their worth in the assessment of men with LUTS. PMID:19468436

Vibration characteristics of 1/8-scale dynamic models of the space-shuttle solid-rocket boosters

NASA Technical Reports Server (NTRS)

Leadbetter, S. A.; Stephens, W.; Sewall, J. L.; Majka, J. W.; Barret, J. R.

1976-01-01

Vibration tests and analyses of six 1/8 scale models of the space shuttle solid rocket boosters are reported. Natural vibration frequencies and mode shapes were obtained for these aluminum shell models having internal solid fuel configurations corresponding to launch, midburn (maximum dynamic pressure), and near endburn (burnout) flight conditions. Test results for longitudinal, torsional, bending, and shell vibration frequencies are compared with analytical predictions derived from thin shell theory and from finite element plate and beam theory. The lowest analytical longitudinal, torsional, bending, and shell vibration frequencies were within + or - 10 percent of experimental values. The effects of damping and asymmetric end skirts on natural vibration frequency were also considered. The analytical frequencies of an idealized full scale space shuttle solid rocket boosted structure are computed with and without internal pressure and are compared with the 1/8 scale model results.

40 CFR 147.1803 - Existing Class I and III wells authorized by rule-maximum injection pressure.

Code of Federal Regulations, 2010 CFR

2010-07-01

... authorized by rule-maximum injection pressure. 147.1803 Section 147.1803 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) WATER PROGRAMS (CONTINUED) STATE, TRIBAL, AND EPA-ADMINISTERED...—maximum injection pressure. The owner or operator shall limit injection pressure to the lesser of: (a) A...

Effect of medial arch support foot orthosis on plantar pressure distribution in females with mild-to-moderate hallux valgus after one month of follow-up.

PubMed

Farzadi, Maede; Safaeepour, Zahra; Mousavi, Mohammad E; Saeedi, Hassan

2015-04-01

Higher plantar pressures at the medial forefoot are reported in hallux valgus. Foot orthoses with medial arch support are considered as an intervention in this pathology. However, little is known about the effect of foot orthoses on plantar pressure distribution in hallux valgus. To investigate the effect of a foot orthosis with medial arch support on pressure distribution in females with mild-to-moderate hallux valgus. Quasi-experimental. Sixteen female volunteers with mild-to-moderate hallux valgus participated in this study and used a medial arch support foot orthosis for 4 weeks. Plantar pressure for each participant was assessed using the Pedar-X(®) in-shoe system in four conditions including shoe-only and foot orthosis before and after the intervention. The use of the foot orthosis for 1 month led to a decrease in peak pressure and maximum force under the hallux, first metatarsal, and metatarsals 3-5 (p < 0.05). In the medial midfoot region, peak pressure, maximum force, and contact area were significantly higher with the foot orthosis than shoe-only before and after the intervention (p = 0.00). A foot orthosis with medial arch support could reduce pressure beneath the hallux and the first metatarsal head by transferring the load to the other regions. It would appear that this type of foot orthosis can be an effective method of intervention in this pathology. Findings of this study will improve the clinical knowledge about the effect of the medial arch support foot orthosis used on plantar pressure distribution in hallux valgus pathology. © The International Society for Prosthetics and Orthotics 2014.

MIS High-Purity Plutonium Oxide Hydride Product 5501579 (SSR124): Final Report

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

Veirs, Douglas Kirk; Stroud, Mary Ann; Berg, John M.

A high-purity plutonium dioxide material from the Material Identification and Surveillance (MIS) Program inventory has been studied with regard to gas generation and corrosion in a storage environment. Sample 5501579 represents process plutonium oxides from hydride oxide from Rocky Flats that are currently stored in 3013 containers. After calcination to 950°C, the material contained 87.42% plutonium with no major impurities. This study followed over time, the gas pressure of a sample with nominally 0.5 wt% water in a sealed container with an internal volume scaled to 1/500th of the volume of a 3013 container. Gas compositions were measured periodically overmore » a six year period. The maximum observed gas pressure was 124 kPa. The increase over the initial pressure of 70 kPa was primarily due to generation of nitrogen and carbon dioxide gas. Hydrogen and oxygen were minor components of the headspace gas. At the completion of the study, the internal components of the sealed container showed signs of corrosion.« less

40 CFR 63.7944 - How do I determine the maximum HAP vapor pressure of my remediation material?

Code of Federal Regulations, 2010 CFR

2010-07-01

... vapor pressure of my remediation material? 63.7944 Section 63.7944 Protection of Environment... Pollutants: Site Remediation Performance Tests § 63.7944 How do I determine the maximum HAP vapor pressure of my remediation material? (a) You must determine the maximum HAP vapor pressure of your remediation...

Real time identification of the internal combustion engine combustion parameters based on the vibration velocity signal

NASA Astrophysics Data System (ADS)

Zhao, Xiuliang; Cheng, Yong; Wang, Limei; Ji, Shaobo

2017-03-01

Accurate combustion parameters are the foundations of effective closed-loop control of engine combustion process. Some combustion parameters, including the start of combustion, the location of peak pressure, the maximum pressure rise rate and its location, can be identified from the engine block vibration signals. These signals often include non-combustion related contributions, which limit the prompt acquisition of the combustion parameters computationally. The main component in these non-combustion related contributions is considered to be caused by the reciprocating inertia force excitation (RIFE) of engine crank train. A mathematical model is established to describe the response of the RIFE. The parameters of the model are recognized with a pattern recognition algorithm, and the response of the RIFE is predicted and then the related contributions are removed from the measured vibration velocity signals. The combustion parameters are extracted from the feature points of the renovated vibration velocity signals. There are angle deviations between the feature points in the vibration velocity signals and those in the cylinder pressure signals. For the start of combustion, a system bias is adopted to correct the deviation and the error bound of the predicted parameters is within 1.1°. To predict the location of the maximum pressure rise rate and the location of the peak pressure, algorithms based on the proportion of high frequency components in the vibration velocity signals are introduced. Tests results show that the two parameters are able to be predicted within 0.7° and 0.8° error bound respectively. The increase from the knee point preceding the peak value point to the peak value in the vibration velocity signals is used to predict the value of the maximum pressure rise rate. Finally, a monitoring frame work is inferred to realize the combustion parameters prediction. Satisfactory prediction for combustion parameters in successive cycles is achieved, which validates the proposed methods.

Standard values of maximum tongue pressure taken using newly developed disposable tongue pressure measurement device.

PubMed

Utanohara, Yuri; Hayashi, Ryo; Yoshikawa, Mineka; Yoshida, Mitsuyoshi; Tsuga, Kazuhiro; Akagawa, Yasumasa

2008-09-01

It is clinically important to evaluate tongue function in terms of rehabilitation of swallowing and eating ability. We have developed a disposable tongue pressure measurement device designed for clinical use. In this study we used this device to determine standard values of maximum tongue pressure in adult Japanese. Eight hundred fifty-three subjects (408 male, 445 female; 20-79 years) were selected for this study. All participants had no history of dysphagia and maintained occlusal contact in the premolar and molar regions with their own teeth. A balloon-type disposable oral probe was used to measure tongue pressure by asking subjects to compress it onto the palate for 7 s with maximum voluntary effort. Values were recorded three times for each subject, and the mean values were defined as maximum tongue pressure. Although maximum tongue pressure was higher for males than for females in the 20-49-year age groups, there was no significant difference between males and females in the 50-79-year age groups. The maximum tongue pressure of the seventies age group was significantly lower than that of the twenties to fifties age groups. It may be concluded that maximum tongue pressures were reduced with primary aging. Males may become weaker with age at a faster rate than females; however, further decreases in strength were in parallel for male and female subjects.

Comparison of water and air charged transducer catheter pressures in the evaluation of cystometrogram and voiding pressure studies.

PubMed

McKinney, Timothy B; Babin, Elizabeth A; Ciolfi, Veronica; McKinney, Cynthia R; Shah, Nima

2018-04-01

Air-charged (AC) and water-perfused (WP) catheters have been evaluated for differences in measuring pressures for voiding dysfunction. Typically, a two-catheter system was used. We believe that simultaneous pressure measurements with AC and WP in a single catheter will provide analogous pressures for coughs, Valsalvas, and maximum pressures in voiding pressure studies (VPS). This IRB approved prospective study included 50 women over age 21. AC dual TDOC catheters were utilized. The water-filling channel served as the bladder filler and the water pressure readings. Patients were evaluated with empty bladders and at volumes of 50-100 mL, 200 mL, and maximum capacity with cough and Valsalva maneuvers. Comparative analysis was performed on maximum stress peak pressures. At maximum bladder capacity, VPS was done and maximum voiding pressure was recorded. Comparing coughs and Valsalva maneuvers pressures, there was significant increase in variability between AC and WP measurements with less than 50 mL volume (P < 0.001). Significant correlations were observed between AC and WP measurements for coughs and Valsalvas with bladder volume over 50 mL. Visual impression showed virtually identical tracings. Cough measurements had an average difference of 0.25 cmH 2 O (±8.81) and Valsalva measurements had an average difference of 3.15 cmH 2 O (±4.72). Thirty-eight women had usable maximum voiding pressure measurements and had a strong correlation. Cystometrogram and maximum voiding pressure measurements done with either water or air charged catheters will yield similarly accurate results and are comparable. Results suggest more variability at low bladder volumes <50 mL. © 2018 Wiley Periodicals, Inc.

A first-principles model for orificed hollow cathode operation

NASA Technical Reports Server (NTRS)

Salhi, A.; Turchi, P. J.

1992-01-01

A theoretical model describing orificed hollow cathode discharge is presented. The approach adopted is based on a purely analytical formulation founded on first principles. The present model predicts the emission surface temperature and plasma properties such as electron temperature, number densities and plasma potential. In general, good agreements between theory and experiment are obtained. Comparison of the results with the available related experimental data shows a maximum difference of 10 percent in emission surface temperature, 20 percent in electron temperature and 35 percent in plasma potential. In case of the variation of the electron number density with the discharge current a maximum discrepancy of 36 percent is obtained. However, in the case of the variation with the cathode internal pressure, the predicted electron number density is higher than the experimental data by a maximum factor of 2.

Assessment and Accommodation of Thermal Expansion of the Internal Active Thermal Control System Coolant During Launch to On-Orbit Activation of International Space Station Elements

NASA Technical Reports Server (NTRS)

Edwards, Darryl; Ungar, Eugene K.; Holt, James M.

2002-01-01

The International Space Station (ISS) employs an Internal Active Thermal Control System (IATCS) comprised of several single-phase water coolant loops. These coolant loops are distributed throughout the ISS pressurized elements. The primary element coolant loops (i.e. U.S. Laboratory module) contain a fluid accumulator to accomodate thermal expansion of the system. Other element coolant loops are parasitic (i.e. Airlock), have no accumulator, and require an alternative approach to insure that the system maximum design pressure (MDP) is not exceeded during the Launch to Activation (LTA) phase. During this time the element loops is a stand alone closed system. The solution approach for accomodating thermal expansion was affected by interactions of system components and their particular limitations. The mathematical solution approach was challenged by the presence of certain unknown or not readily obtainable physical and thermodynamic characteristics of some system components and processes. The purpose of this paper is to provide a brief description of a few of the solutions that evolved over time, a novel mathematical solution to eliminate some of the unknowns or derive the unknowns experimentally, and the testing and methods undertaken.

Assessment and Accommodation of Thermal Expansion of the Internal Active Thermal Control System Coolant During Launch to On-Orbit Activation of International Space Station Elements

NASA Technical Reports Server (NTRS)

Edwards, J. Darryl; Ungar, Eugene K.; Holt, James M.; Turner, Larry D. (Technical Monitor)

2001-01-01

The International Space Station (ISS) employs an Internal Active Thermal Control System (IATCS) comprised of several single-phase water coolant loops. These coolant loops are distributed throughout the ISS pressurized elements. The primary element coolant loops (i.e., US Laboratory module) contain a fluid accumulator to accommodate thermal expansion of the system. Other element coolant loops are parasitic (i.e., Airlock), have no accumulator, and require an alternative approach to insure that the system Maximum Design Pressure (MDP) is not exceeded during the Launch to Activation phase. During this time the element loop is a stand alone closed individual system. The solution approach for accommodating thermal expansion was affected by interactions of system components and their particular limitations. The mathematical solution approach was challenged by the presence of certain unknown or not readily obtainable physical and thermodynamic characteristics of some system components and processes. The purpose of this paper is to provide a brief description of a few of the solutions that evolved over time, a novel mathematical solution to eliminate some of the unknowns or derive the unknowns experimentally, and the testing and methods undertaken.

Simulated impact damage in a thick graphite/epoxy laminate using spherical indenters

NASA Technical Reports Server (NTRS)

Poe, C. C., Jr.

1988-01-01

The extent of fiber damage due to low-velocity impacts was determined for very thick graphite/epoxy laminates. The impacts were simulated by pressing spherical indenters against the laminates. After the forces were applied, the laminate was cut into smaller pieces so that each piece contained a test site. Then the pieces were deplied and the individual plies were examined to determine the extent of fiber damage. Broken fibers were found in the outer layers directly beneath the contact site. The locus of broken fibers resembled cracks. The cracks were more or less oriented in the direction of the fibers in the contiguous layers. The maximum length and depth of the cracks increased with increasing contact pressure and indenter diameter. The length and depth of the cracks were also predicted using maximum compression and shear stress criteria. The internal stresses were calculated using Hertz's law and Love's solution for pressure applied on part of the boundary of a semi-infinite body. The predictions and measurements were in good agreement.

Fission Product Release and Survivability of UN-Kernel LWR TRISO Fuel

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

Besmann, Theodore M; Ferber, Mattison K; Lin, Hua-Tay

2014-01-01

A thermomechanical assessment of the LWR application of TRISO fuel with UN kernels was performed. Fission product release under operational and transient temperature conditions was determined by extrapolation from range calculations and limited data from irradiated UN pellets. Both fission recoil and diffusive release were considered and internal particle pressures computed for both 650 and 800 m diameter kernels as a function of buffer layer thickness. These pressures were used in conjunction with a finite element program to compute the radial and tangential stresses generated with a TRISO particle as a function of fluence. Creep and swelling of the innermore » and outer pyrolytic carbon layers were included in the analyses. A measure of reliability of the TRISO particle was obtained by measuring the probability of survival of the SiC barrier layer and the maximum tensile stress generated in the pyrolytic carbon layers as a function of fluence. These reliability estimates were obtained as functions of the kernel diameter, buffer layer thickness, and pyrolytic carbon layer thickness. The value of the probability of survival at the end of irradiation was inversely proportional to the maximum pressure.« less

Increasing Reliability of a Small 2-Stroke Internal Combustion Engine for Dynamically Changing Altitudes

DTIC Science & Technology

2012-03-01

63 Figure 20: New 3 inch stainless pipe used as an intake manifold...speed range of 1,000 RPM to 4,000 RPM. Six electric heaters with a total capacity of 900 W were used to heat the inlet air allowing a maximum...of the engine volume and had a gummy diaphragm attached to reduce pressure and flow pulsations to allow for more accurate air flow measurements

A Prospective International Multicentre Cohort Study of Intraoperative Heart Rate and Systolic Blood Pressure and Myocardial Injury After Noncardiac Surgery: Results of the VISION Study

PubMed Central

Abbott, Tom E. F.; Pearse, Rupert M.; Archbold, R. Andrew; Ahmad, Tahania; Niebrzegowska, Edyta; Wragg, Andrew; Rodseth, Reitze N.; Devereaux, Philip J.

2018-01-01

BACKGROUND: The association between intraoperative cardiovascular changes and perioperative myocardial injury has chiefly focused on hypotension during noncardiac surgery. However, the relative influence of blood pressure and heart rate (HR) remains unclear. We investigated both individual and codependent relationships among intraoperative HR, systolic blood pressure (SBP), and myocardial injury after noncardiac surgery (MINS). METHODS: Secondary analysis of the Vascular Events in Noncardiac Surgery Cohort Evaluation (VISION) study, a prospective international cohort study of noncardiac surgical patients. Multivariable logistic regression analysis tested for associations between intraoperative HR and/or SBP and MINS, defined by an elevated serum troponin T adjudicated as due to an ischemic etiology, within 30 days after surgery. Predefined thresholds for intraoperative HR and SBP were: maximum HR >100 beats or minimum HR <55 beats per minute (bpm); maximum SBP >160 mm Hg or minimum SBP <100 mm Hg. Secondary outcomes were myocardial infarction and mortality within 30 days after surgery. RESULTS: After excluding missing data, 1197 of 15,109 patients (7.9%) sustained MINS, 454 of 16,031 (2.8%) sustained myocardial infarction, and 315 of 16,061 patients (2.0%) died within 30 days after surgery. Maximum intraoperative HR >100 bpm was associated with MINS (odds ratio [OR], 1.27 [1.07–1.50]; P < .01), myocardial infarction (OR, 1.34 [1.05–1.70]; P = .02), and mortality (OR, 2.65 [2.06–3.41]; P < .01). Minimum SBP <100 mm Hg was associated with MINS (OR, 1.21 [1.05–1.39]; P = .01) and mortality (OR, 1.81 [1.39–2.37]; P < .01), but not myocardial infarction (OR, 1.21 [0.98–1.49]; P = .07). Maximum SBP >160 mm Hg was associated with MINS (OR, 1.16 [1.01–1.34]; P = .04) and myocardial infarction (OR, 1.34 [1.09–1.64]; P = .01) but, paradoxically, reduced mortality (OR, 0.76 [0.58–0.99]; P = .04). Minimum HR <55 bpm was associated with reduced MINS (OR, 0.70 [0.59–0.82]; P < .01), myocardial infarction (OR, 0.75 [0.58–0.97]; P = .03), and mortality (OR, 0.58 [0.41–0.81]; P < .01). Minimum SBP <100 mm Hg with maximum HR >100 bpm was more strongly associated with MINS (OR, 1.42 [1.15–1.76]; P < .01) compared with minimum SBP <100 mm Hg alone (OR, 1.20 [1.03–1.40]; P = .02). CONCLUSIONS: Intraoperative tachycardia and hypotension are associated with MINS. Further interventional research targeting HR/blood pressure is needed to define the optimum strategy to reduce MINS. PMID:29077608

Relationship between abdominal and pelvic floor muscle activation and intravaginal pressure during pelvic floor muscle contractions in healthy continent women.

PubMed

Madill, Stéphanie J; McLean, Linda

2006-01-01

Activation of the abdominal muscles might contribute to the generation of a strong pelvic floor muscle contraction, and consequently may contribute to the continence mechanism in women. The purpose of this study was to determine the abdominal muscle activation levels and the patterns of muscle activity associated with voluntary pelvic floor muscle (PFM) contractions in urinary continent women. Fifteen healthy continent women participated. They performed three maximal contractions of each of the four abdominal muscles and of their PFMs while in supine. Abdominal and PFM activity was recorded using electromyography (EMG), and intravaginal pressure was recorded using a custom modified Femiscan probe. During voluntary maximal PFM contractions, rectus abdominus was activated to 9.61 (+/-7.42)% maximal voluntary electrical activity (MVE), transversus abdominus was activated to 224.30(+/-47.4)% MVE, the external obliques were activated to 18.72(+/-13.33)% MVE, and the internal obliques were activated to 81.47(+/-63.57)% MVE. A clear pattern of activation emerged, whereby the transversus abdominus, internal oblique, and rectus abdominus muscles worked with the PFM in the initial generation of maximal intravaginal pressure. PFM activity predominated in the initial rise in lower vaginal pressure, with later increases in pressure (up to 70% maximum pressure) being associated with the combined activation of the PFM, rectus abdominus, internal obliques, and transverses abdominus. These abdominal muscles were the primary source of intravaginal pressure increases in the latter 30% of the task, whereas there was little increase in PFM activation from this point on. The external oblique muscles showed no clear pattern of activity, but worked at approximately 20% MVE throughout the PFM contractions, suggesting that their role may be predominantly in postural setting prior to the initiation of intravaginal pressure increases. Defined patterns of abdominal muscle activity were found in response to voluntary PFM contractions in healthy continent women. (c) 2006 Wiley-Liss, Inc.

Simulated impact damage in a thick graphite/epoxy laminate using spherical indenters

NASA Technical Reports Server (NTRS)

Poe, C. C., Jr.

1988-01-01

A study was made to determine the extent of fiber damage caused by low-velocity impact of spherical impactors to a very thick graphite/epoxy laminate. The laminate was cut from a filament wound case being developed for the Space Shuttle solid rocket motors. The case was wound using a wet process with AS4W graphite fiber and HBRF-55A epoxy. Impacts were simulated under quasi-static conditions by pressing hemispherically shaped indenters against the laminate at different locations. The contact force and indenter diameter were varied from location to location. The forces were chosen for each indenter diameter to produce contact pressures below and above that required to initiate damage. After the forces were applied, the laminate was cut into smaller pieces so that each piece contained a test site. The pieces were then deplied and the individual plies examined to determine the extent of fiber damage. Broken fibers were found in the outer layers directly beneath the contact site. The locus of broken fibers in each layer resembled a crack normal to the direction of the fibers. The maximum length and depth of the cracks increased with increasing contact pressure and indenter diameter. The internal stresses in the laminate were calculated using Hertz's law and Love's solution for pressure applied on part of the boundary of a semi-infinite body. The maximum length and depth of the cracks were predicted using a maximum shear stress criterion. Predictions and measurements were in good agreement.

49 CFR 192.619 - Maximum allowable operating pressure: Steel or plastic pipelines.

Code of Federal Regulations, 2010 CFR

2010-10-01

... plastic pipelines. 192.619 Section 192.619 Transportation Other Regulations Relating to Transportation... Operations § 192.619 Maximum allowable operating pressure: Steel or plastic pipelines. (a) No person may operate a segment of steel or plastic pipeline at a pressure that exceeds a maximum allowable operating...

49 CFR 192.623 - Maximum and minimum allowable operating pressure; Low-pressure distribution systems.

Code of Federal Regulations, 2012 CFR

2012-10-01

... distribution systems. (a) No person may operate a low-pressure distribution system at a pressure high enough to...) No person may operate a low pressure distribution system at a pressure lower than the minimum... 49 Transportation 3 2012-10-01 2012-10-01 false Maximum and minimum allowable operating pressure...

49 CFR 192.623 - Maximum and minimum allowable operating pressure; Low-pressure distribution systems.

Code of Federal Regulations, 2011 CFR

2011-10-01

... distribution systems. (a) No person may operate a low-pressure distribution system at a pressure high enough to...) No person may operate a low pressure distribution system at a pressure lower than the minimum... 49 Transportation 3 2011-10-01 2011-10-01 false Maximum and minimum allowable operating pressure...

49 CFR 192.623 - Maximum and minimum allowable operating pressure; Low-pressure distribution systems.

Code of Federal Regulations, 2013 CFR

2013-10-01

... distribution systems. (a) No person may operate a low-pressure distribution system at a pressure high enough to...) No person may operate a low pressure distribution system at a pressure lower than the minimum... 49 Transportation 3 2013-10-01 2013-10-01 false Maximum and minimum allowable operating pressure...

49 CFR 192.623 - Maximum and minimum allowable operating pressure; Low-pressure distribution systems.

Code of Federal Regulations, 2014 CFR

2014-10-01

... distribution systems. (a) No person may operate a low-pressure distribution system at a pressure high enough to...) No person may operate a low pressure distribution system at a pressure lower than the minimum... 49 Transportation 3 2014-10-01 2014-10-01 false Maximum and minimum allowable operating pressure...

49 CFR 192.623 - Maximum and minimum allowable operating pressure; Low-pressure distribution systems.

Code of Federal Regulations, 2010 CFR

2010-10-01

... distribution systems. (a) No person may operate a low-pressure distribution system at a pressure high enough to...) No person may operate a low pressure distribution system at a pressure lower than the minimum... 49 Transportation 3 2010-10-01 2010-10-01 false Maximum and minimum allowable operating pressure...

KSC-2009-6123

NASA Image and Video Library

2009-11-05

CAPE CANAVERAL, Fla. – Pratt & Whitney Rocketdyne technicians install a space shuttle main engine on space shuttle Endeavour in Orbiter Processing Facility Bay 2 at NASA's Kennedy Space Center in Florida. The engine will fly on the shuttle's STS-130 mission to the International Space Station. Even though this engine weighs one-seventh as much as a locomotive engine, its high-pressure fuel pump alone delivers as much horsepower as 28 locomotives, while its high-pressure oxidizer pump delivers the equivalent horsepower of an additional 11 locomotives. The maximum equivalent horsepower developed by the shuttle's three main engines is more than 37 million horsepower. Endeavour is targeted to launch Feb. 4, 2010. Photo credit: NASA/Jim Grossmann

KSC-2009-6125

NASA Image and Video Library

2009-11-05

CAPE CANAVERAL, Fla. – A Pratt & Whitney Rocketdyne technician carefully maneuvers a space shuttle main engine into position on space shuttle Endeavour in Orbiter Processing Facility Bay 2 at NASA's Kennedy Space Center in Florida. The engine will fly on the shuttle's STS-130 mission to the International Space Station. Even though this engine weighs one-seventh as much as a locomotive engine, its high-pressure fuel pump alone delivers as much horsepower as 28 locomotives, while its high-pressure oxidizer pump delivers the equivalent horsepower of an additional 11 locomotives. The maximum equivalent horsepower developed by the shuttle's three main engines is more than 37 million horsepower. Endeavour is targeted to launch Feb. 4, 2010. Photo credit: NASA/Jim Grossmann

KSC-2009-6124

NASA Image and Video Library

2009-11-05

CAPE CANAVERAL, Fla. – A Pratt & Whitney Rocketdyne technician carefully maneuvers a space shuttle main engine into position on space shuttle Endeavour in Orbiter Processing Facility Bay 2 at NASA's Kennedy Space Center in Florida. The engine will fly on the shuttle's STS-130 mission to the International Space Station. Even though this engine weighs one-seventh as much as a locomotive engine, its high-pressure fuel pump alone delivers as much horsepower as 28 locomotives, while its high-pressure oxidizer pump delivers the equivalent horsepower of an additional 11 locomotives. The maximum equivalent horsepower developed by the shuttle's three main engines is more than 37 million horsepower. Endeavour is targeted to launch Feb. 4, 2010. Photo credit: NASA/Jim Grossmann

Phase equilibria computations of multicomponent mixtures at specified internal energy and volume

NASA Astrophysics Data System (ADS)

Myint, Philip C.; Nichols, Albert L., III; Springer, H. Keo

2017-06-01

Hydrodynamic simulation codes for high-energy density science applications often use internal energy and volume as their working variables. As a result, the codes must determine the thermodynamic state that corresponds to the specified energy and volume by finding the global maximum in entropy. This task is referred to as the isoenergetic-isochoric flash. Solving it for multicomponent mixtures is difficult because one must find not only the temperature and pressure consistent with the energy and volume, but also the number of phases present and the composition of the phases. The few studies on isoenergetic-isochoric flash that currently exist all require the evaluation of many derivatives that can be tedious to implement. We present an alternative approach that is based on a derivative-free method: particle swarm optimization. The global entropy maximum is found by running several instances of particle swarm optimization over different sets of randomly selected points in the search space. For verification, we compare the predicted temperature and pressure to results from the related, but simpler problem of isothermal-isobaric flash. All of our examples involve the equation of state we have recently developed for multiphase mixtures of the energetic materials HMX, RDX, and TNT. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

The changes in resting anal pressure after performing full-thickness rectal advancement flaps.

PubMed

Balciscueta, Zutoia; Uribe, Natalia; Mínguez, Miguel; García-Granero, Eduardo

2017-09-01

Advancement flap is an accepted approach for treating complex fistula-in-ano.The purpose was to evaluate the changes in resting pressure along the anal canal after performing a full-thickness flap. Manometric review of patients who have undergone a full-thickness rectal advancement flap procedure for complex anal fistulas of cryptoglandular origin. Recurrence and continence were evaluated. Resting Anal Pressure was assessed along the anal canal by two measures: maximum resting pressure(MRP) and inferior resting pressure(IRP) at 0.5 cm from the anal verge. 119 patients were evaluated. Overall recurrence rate was5.9%. Anal continence was maintained intact in 76.5%. Manometric study showed a significant decrease in postoperative MRP(90.6 ± 31.9 to 45.2 ± 20 mmHg; p < 0.001), while IRP values did not differ significantly(28.2 ± 18.3 to 23.2 ± 13.5 mmHg; p = 0.1). Performing a full-thickness rectal flap causes a decrease of the MRP in the middle third of the anal canal, due to the inclusion of the internal sphincter in flap. It seems crucial to preserve the distal internal sphincter intact as it helps both to maintain the resting pressure in the lower third and avoid deformities of the anal margin. Copyright © 2017 Elsevier Inc. All rights reserved.

Optimizing the effectiveness of a mechanical suture-based anulus fibrosus repair construct in an acute failure laboratory simulation.

PubMed

Bartlett, Ashley; Wales, Larry; Houfburg, Rodney; Durfee, William K; Griffith, Steven L; Bentley, Ishmael

2013-10-01

In vitro comparative, laboratory experiments. This study developed a laboratory apparatus that measured resistance to failure using pressures similar to intradiscal pressure of a lumbar spinal disk. Various combinations of an anular repair device were compared. Herniated material of the intervertebral disk is removed during a lumbar discectomy; however, the defect in the anulus fibrosus remains and can provide a pathway for future herniation. Repairing the anulus fibrosus could mitigate this reherniation and improve patient outcomes. A pneumatic cylinder was used to increase the pressure of a sealed chamber until artificial nucleus pulposus material was expulsed through either a 3-mm circular (diameter) or a 6-mm slit anular defect created in a surrogate anulus fibrosus. Each unrepaired condition was compared with 3 repaired conditions using a commercially available soft tissue repair system. The repaired conditions included: (1) a single tension band; (2) 2 tension bands in a cruciate pattern; or (3) 2 tension bands in a parallel pattern. Maximum pressure at the point of extrusion of the internal chamber material and failure or nonfailure of the repair was measured. Significant differences were detected (P<0.05) in maximum failure pressures for the nonrepaired (control) versus repaired conditions. With 1 or 2 tension bands repairing the circular defect, the maximum failure pressure increased by approximately 76% and 131%, respectively. In addition, the failure pressure for 2 tension bands in either a cruciate or parallel configuration was not different, and was approximately 32% higher (P<0.05) than a single tension band in the case of the circular defect. Similar results were seen for the slit defect, with the exception that no difference between the repaired conditions (ie, single vs. 2 tension bands) was detected. This laboratory simulation demonstrated that repairing the anulus fibrosus after a discectomy procedure can be beneficial for retaining intradiscal material. The use of 2 tension bands, versus a single tension band, in either a cruciate or parallel configuration may further improve the ability to retain disk material.

46 CFR 52.01-55 - Increase in maximum allowable working pressure.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 46 Shipping 2 2011-10-01 2011-10-01 false Increase in maximum allowable working pressure. 52.01-55 Section 52.01-55 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING POWER BOILERS General Requirements § 52.01-55 Increase in maximum allowable working pressure. (a) When...

46 CFR 52.01-55 - Increase in maximum allowable working pressure.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 46 Shipping 2 2012-10-01 2012-10-01 false Increase in maximum allowable working pressure. 52.01-55 Section 52.01-55 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING POWER BOILERS General Requirements § 52.01-55 Increase in maximum allowable working pressure. (a) When...

46 CFR 52.01-55 - Increase in maximum allowable working pressure.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 2 2010-10-01 2010-10-01 false Increase in maximum allowable working pressure. 52.01-55 Section 52.01-55 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING POWER BOILERS General Requirements § 52.01-55 Increase in maximum allowable working pressure. (a) When...

46 CFR 52.01-55 - Increase in maximum allowable working pressure.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 46 Shipping 2 2014-10-01 2014-10-01 false Increase in maximum allowable working pressure. 52.01-55 Section 52.01-55 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING POWER BOILERS General Requirements § 52.01-55 Increase in maximum allowable working pressure. (a) When...

46 CFR 52.01-55 - Increase in maximum allowable working pressure.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 46 Shipping 2 2013-10-01 2013-10-01 false Increase in maximum allowable working pressure. 52.01-55 Section 52.01-55 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING POWER BOILERS General Requirements § 52.01-55 Increase in maximum allowable working pressure. (a) When...

Results for the Aboveground Configuration of the Boiling Water Reactor Dry Cask Simulator

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

Durbin, Samuel G.; Lindgren, Eric Richard

The thermal performance of commercial nuclear spent fuel dry storage casks are evaluated through detailed numerical analysis. These modeling efforts are completed by the vendor to demonstrate performance and regulatory compliance. The calculations are then independently verified by the Nuclear Regulatory Commission (NRC). Carefully measured data sets generated from testing of full sized casks or smaller cask analogs are widely recognized as vital for validating these models. Recent advances in dry storage cask designs have significantly increased the maximum thermal load allowed in a cask in part by increasing the efficiency of internal conduction pathways and also by increasing themore » internal convection through greater canister helium pressure. These same canistered cask systems rely on ventilation between the canister and the overpack to convect heat away from the canister to the environment for both above and belowground configurations. While several testing programs have been previously conducted, these earlier validation attempts did not capture the effects of elevated helium pressures or accurately portray the external convection of aboveground and belowground canistered dry cask systems. The purpose of the current investigation was to produce data sets that can be used to test the validity of the assumptions associated with the calculations used to determine steady-state cladding temperatures in modern dry casks that utilize elevated helium pressure in the sealed canister in an aboveground configuration. An existing electrically heated but otherwise prototypic BWR Incoloy-clad test assembly was deployed inside of a representative storage basket and cylindrical pressure vessel that represents a vertical canister system. The symmetric single assembly geometry with well-controlled boundary conditions simplifies interpretation of results. The arrangement of ducting was used to mimic conditions for an aboveground storage configuration in a vertical, dry cask systems with canisters. Transverse and axial temperature profiles were measured for a wide range of decay power and helium cask pressures. Of particular interest was the evaluation of the effect of increased helium pressure on peak cladding temperatures (PCTs) for identical thermal loads. All steady state peak temperatures and induced flow rates increased with increasing assembly power. Peak cladding temperatures decreased with increasing internal helium pressure for a given assembly power, indicating increased internal convection. In addition, the location of the PCT moved from near the top of the assembly to ~1/3 the height of the assembly for the highest (8 bar absolute) to the lowest (0 bar absolute) pressure studied, respectively. This shift in PCT location is consistent with the varying contribution of convective heat transfer proportional with of internal helium pressure.« less

Combined Determination of Elastic Properties and Structure of Coesite under Simulated Mantle Conditions

NASA Astrophysics Data System (ADS)

Mueller, H. J.; Schilling, F. R.; Lauterjung, J.; Lathe, C.

2001-12-01

The high pressure SiO2-polymorph coesite seems to be an important mineral in the subduction process including crustal material (Chopin, 1984; Schreyer, 1995). The quartz to coesite transition is thus of fundamental importance to understand the processes within a subducting crust. Furthermore, the nature of the quartz to coesite transition is discussed controversially, because high pressure XRD-studies suggest an intermediate phase during the transformation process (Zinn et al., 1997). For the combined determination of elastic properties and structure a cubic multi-anvil high pressure apparatus (MAX80) was used. For the maximum sample volume of 20 mm3 the pressure limit is about 7GPa. The pressure is measured by use of NaCl as an internal pressure marker with calibrated PVT-data. The maximum temperature of about 2,000K is generated by an internal graphite heater and controlled by a thermocouple. The synchrotron beam (100x100 microns) is guided by a collimator through the sample between the anvils. For energy-dispersive X-ray diffraction, a Ge-solid state detector analyses the diffracted white beam at a fixed angle. The compressional and shear wave velocities were determined simultaneously by ultrasonic interferometry inside MAX80. Two of the six anvils are equipped with overtone polished lithium niobate transducers at their rear side, outside the volume under pressure, for generation and detection of ultrasonic waves between 10 and 60 MHz. Different buffer - reflector combinations and transducer arrangements were used to optimize the critical interference between both sample echoes. Therefore MAX80 is equipped for asymmetrical and symmetrical interferometric set-ups, i.e. compressional and shear waves are generated from the same or from two anvils, opposite to each other. We used for our transient measurements 3 natural fine-grained quartzites from Turkey and Germany. As a first step the pressure was increased gradually up to 4GPa at ambient temperature. At each pressure Vp and Vs was measured by ultrasonic interferometry. After reaching a given pressure, temperature was increased. At 4.5GPa and 800\\deg C the phase transition to coesite took place in less than 2 minutes. The fast kinetic of transformation was observed by synchrotron radiation. The compressional wave velocity increased by 30% and the shear wave velocity by 10% during the phase transition. The kinetic of the transition was varied by choosing different pressure and temperature conditions. The transformation with lower kinetic was studied in detail by XRD and ultrasonic interferometry. At 4.2 GPa the transformation could not be observed even above 950\\deg C. At 4.5 GPa and 750\\deg C the transition stopped at about 50% transformation, but transforms complete while increasing temperature to 800\\deg C. After the phase transition monitored by X-ray scattering the sample was quenched and Vp and Vs of coesite was measured at ambient temperatures up to the maximum pressure. Small differences in grain size, shape and in minor graphite contents did not change systematically the PT-conditions and kinetics. In addition to the kinetic and change of elastic properties the pressure and temperature derivatives of elastic properties of coesite will be presented.\\Chopin, C., Contr. Min. Petrol., 86 (1984), 107-118\\Schreyer, W., J. Geophys. Res., 100 (1995), 8,353-8,366\\Zinn P., Lauterjung J., Wirth R. & Hinze E. Zeitschrift für Kristallographie, 212 (1997), 691-698.

49 CFR 192.621 - Maximum allowable operating pressure: High-pressure distribution systems.

Code of Federal Regulations, 2012 CFR

2012-10-01

... STANDARDS Operations § 192.621 Maximum allowable operating pressure: High-pressure distribution systems. (a) No person may operate a segment of a high pressure distribution system at a pressure that exceeds the... segment of a distribution system otherwise designed to operate at over 60 p.s.i. (414 kPa) gage, unless...

49 CFR 192.621 - Maximum allowable operating pressure: High-pressure distribution systems.

Code of Federal Regulations, 2011 CFR

2011-10-01

... STANDARDS Operations § 192.621 Maximum allowable operating pressure: High-pressure distribution systems. (a) No person may operate a segment of a high pressure distribution system at a pressure that exceeds the... segment of a distribution system otherwise designed to operate at over 60 p.s.i. (414 kPa) gage, unless...

49 CFR 192.621 - Maximum allowable operating pressure: High-pressure distribution systems.

Code of Federal Regulations, 2010 CFR

2010-10-01

... STANDARDS Operations § 192.621 Maximum allowable operating pressure: High-pressure distribution systems. (a) No person may operate a segment of a high pressure distribution system at a pressure that exceeds the... segment of a distribution system otherwise designed to operate at over 60 p.s.i. (414 kPa) gage, unless...

49 CFR 192.621 - Maximum allowable operating pressure: High-pressure distribution systems.

Code of Federal Regulations, 2014 CFR

2014-10-01

... STANDARDS Operations § 192.621 Maximum allowable operating pressure: High-pressure distribution systems. (a) No person may operate a segment of a high pressure distribution system at a pressure that exceeds the... segment of a distribution system otherwise designed to operate at over 60 p.s.i. (414 kPa) gage, unless...

49 CFR 192.621 - Maximum allowable operating pressure: High-pressure distribution systems.

Code of Federal Regulations, 2013 CFR

2013-10-01

... STANDARDS Operations § 192.621 Maximum allowable operating pressure: High-pressure distribution systems. (a) No person may operate a segment of a high pressure distribution system at a pressure that exceeds the... segment of a distribution system otherwise designed to operate at over 60 p.s.i. (414 kPa) gage, unless...

Internal flow characteristics of a multistage compressor with inlet pressure distortion. [J85-13 turbojet engine studies

NASA Technical Reports Server (NTRS)

Debogdan, C. E.; Moss, J. E., Jr.; Braithwaite, W. M.

1977-01-01

The measured distribution of compressor interstage pressures and temperatures resulting from a 180 deg inlet-total-pressure distortion for a J85-13 turbojet engine is reported. Extensive inner stage instrumentation combined with stepwise rotation of the inlet distortion gave data of high circumferential resolution. The steady-state pressures and temperatures along with the amplitude, extent, and location of the distorted areas are given. Data for 80, 90, and 100 percent of rotor design speed are compared with clean (undistorted) inlet flow conditions to show pressure and temperature behavior within the compressor. Both overall and stagewise compressor performances vary only slightly when clean and distorted inlet conditions are compared. Total and static pressure distortions increase in amplitude in the first few stages of the compressor and then attenuate fairly uniformly to zero at the discharge. Total-temperature distortion induced by the pressure distortion reached a maximum amplitude by the first two stages and decayed only a little through the rest of the compressor. Distortion amplitude tended to peak in line with the screen edges, and, except for total and static pressure in the tip zone, there was little swirl in the axial direction.

High methane natural gas/air explosion characteristics in confined vessel.

PubMed

Tang, Chenglong; Zhang, Shuang; Si, Zhanbo; Huang, Zuohua; Zhang, Kongming; Jin, Zebing

2014-08-15

The explosion characteristics of high methane fraction natural gas were investigated in a constant volume combustion vessel at different initial conditions. Results show that with the increase of initial pressure, the peak explosion pressure, the maximum rate of pressure rise increase due to a higher amount (mass) of flammable mixture, which delivers an increased amount of heat. The increased total flame duration and flame development time result as a consequence of the higher amount of flammable mixture. With the increase of the initial temperature, the peak explosion pressures decrease, but the pressure increase during combustion is accelerated, which indicates a faster flame speed and heat release rate. The maximum value of the explosion pressure, the maximum rate of pressure rise, the minimum total combustion duration and the minimum flame development time is observed when the equivalence ratio of the mixture is 1.1. Additionally, for higher methane fraction natural gas, the explosion pressure and the maximum rate of pressure rise are slightly decreased, while the combustion duration is postponed. The combustion phasing is empirically correlated with the experimental parameters with good fitting performance. Furthermore, the addition of dilute gas significantly reduces the explosion pressure, the maximum rate of pressure rise and postpones the flame development and this flame retarding effect of carbon dioxide is stronger than that of nitrogen. Copyright © 2014 Elsevier B.V. All rights reserved.

Using an extreme bony prominence anatomical model to examine the influence of bed sheet materials and bed making methods on the distribution of pressure on the support surface.

PubMed

Iuchi, Terumi; Nakajima, Yukari; Fukuda, Moriyoshi; Matsuo, Junko; Okamoto, Hiroyuki; Sanada, Hiromi; Sugama, Junko

2014-05-01

Bed sheets generate high surface tension across the support surface and increase pressure to the body through a process known as the hammock effect. Using an anatomical model and a loading device characterized by extreme bony prominences, the present study compared pressure distributions on support surfaces across different bed making methods and bed sheet materials to determine the factors that influence pressure distribution. The model was placed on a pressure mapping system (CONFORMat; NITTA Corp., Osaka, Japan), and interface pressure was measured. Bed sheet elasticity and friction between the support surface and the bed sheets were also measured. For maximum interface pressure, the relative values of the following methods were higher than those of the control method, which did not use any bed sheets: cotton sheets with hospital corners (1.28, p = 0.02), polyester with no corners (1.29, p = 0.01), cotton with no corners (1.31, p = 0.003), and fitted polyester sheets (1.35, p = 0.002). Stepwise multiple regression analysis indicated that maximum interface pressure was negatively correlated with bed sheet elasticity (R(2) = 0.74). A statistically significant negative correlation was observed between maximum interface pressure and immersion depth, which was measured using the loading device (r = -0.40 and p = 0.04). We found that several combinations of bed making methods and bed sheet materials induced maximum interface pressures greater than those observed for the control method. Bed sheet materials influenced maximum interface pressure, and bed sheet elasticity was particularly important in reducing maximum interface pressure. Copyright © 2014 Tissue Viability Society. Published by Elsevier Ltd. All rights reserved.

33 CFR 156.170 - Equipment tests and inspections.

Code of Federal Regulations, 2014 CFR

2014-07-01

... distort under static liquid pressure at least 11/2 times the maximum allowable working pressure; and (iv... static liquid pressure test is successfully completed in the presence of the COTP. The test medium is not... static liquid pressure at least 11/2 times the maximum allowable working pressure; and (5) Each item of...

33 CFR 156.170 - Equipment tests and inspections.

Code of Federal Regulations, 2012 CFR

2012-07-01

... distort under static liquid pressure at least 11/2 times the maximum allowable working pressure; and (iv... static liquid pressure test is successfully completed in the presence of the COTP. The test medium is not... static liquid pressure at least 11/2 times the maximum allowable working pressure; and (5) Each item of...

33 CFR 156.170 - Equipment tests and inspections.

Code of Federal Regulations, 2013 CFR

2013-07-01

... distort under static liquid pressure at least 11/2 times the maximum allowable working pressure; and (iv... static liquid pressure test is successfully completed in the presence of the COTP. The test medium is not... static liquid pressure at least 11/2 times the maximum allowable working pressure; and (5) Each item of...

Numerical Modeling of Mechanical Behavior for Buried Steel Pipelines Crossing Subsidence Strata

PubMed Central

Han, C. J.

2015-01-01

This paper addresses the mechanical behavior of buried steel pipeline crossing subsidence strata. The investigation is based on numerical simulation of the nonlinear response of the pipeline-soil system through finite element method, considering large strain and displacement, inelastic material behavior of buried pipeline and the surrounding soil, as well as contact and friction on the pipeline-soil interface. Effects of key parameters on the mechanical behavior of buried pipeline were investigated, such as strata subsidence, diameter-thickness ratio, buried depth, internal pressure, friction coefficient and soil properties. The results show that the maximum strain appears on the outer transition subsidence section of the pipeline, and its cross section is concave shaped. With the increasing of strata subsidence and diameter-thickness ratio, the out of roundness, longitudinal strain and equivalent plastic strain increase gradually. With the buried depth increasing, the deflection, out of roundness and strain of the pipeline decrease. Internal pressure and friction coefficient have little effect on the deflection of buried pipeline. Out of roundness is reduced and the strain is increased gradually with the increasing of internal pressure. The physical properties of soil have a great influence on the mechanical properties of buried pipeline. The results from the present study can be used for the development of optimization design and preventive maintenance for buried steel pipelines. PMID:26103460

Direct measurements of the pressure distribution along the contact area during droplet impact

NASA Astrophysics Data System (ADS)

Nguyen, Thanh-Vinh; Matsumoto, Kiyoshi; Shimoyama, Isao

2016-11-01

We report direct measurements of the pressure distribution on the contact area during the impact of a droplet on a micropillar array. The measurements were realized using an array of MEMS-based force sensors fabricated underneath the micropillars. We show that immediately after the droplet hits the surface, the pressure becomes maximum at the center of the contact area and this maximum pressure value is more than 10 times larger than the dynamic pressure. This result emphasizes the effect of water-hammer-type pressure during the early stage of the impact. Furthermore, our measurement results demonstrate that the critical pressure associated with Cassie-Wenzel transition agrees well with the maximum capillary pressure of the micropillar array.

MIS High-Purity Plutonium Oxide Metal Oxidation Product TS707001 (SSR123): Final Report

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

Veirs, Douglas Kirk; Stroud, Mary Ann; Berg, John M.

A high-purity plutonium dioxide material from the Material Identification and Surveillance (MIS) Program inventory has been studied with regard to gas generation and corrosion in a storage environment. Sample TS707001 represents process plutonium oxides from several metal oxidation operations as well as impure and scrap plutonium from Hanford that are currently stored in 3013 containers. After calcination to 950°C, the material contained 86.98% plutonium with no major impurities. This study followed over time, the gas pressure of a sample with nominally 0.5 wt% water in a sealed container with an internal volume scaled to 1/500th of the volume of amore » 3013 container. Gas compositions were measured periodically over a six year period. The maximum observed gas pressure was 138 kPa. The increase over the initial pressure of 80 kPa was primarily due to generation of nitrogen and carbon dioxide gas in the first six months. Hydrogen and oxygen were minor components of the headspace gas. At the completion of the study, the internal components of the sealed container showed signs of corrosion, including pitting.« less

Possible oriented transition of multiple-emulsion globules with asymmetric internal structures in a microfluidic constriction

NASA Astrophysics Data System (ADS)

Wang, Jingtao; Li, Xiaoduan; Wang, Xiaoyong; Guan, Jing

2014-05-01

When a globule with a complete symmetry (such as simple spherical droplets and concentric double emulsions) is transiting in a constriction tube, there is only one pattern of the transition. However, for a multiple-emulsion globule with asymmetric internal structures, there are many possible patterns with different pressure drops Δp due to various initial orientations of the inner droplets. In this paper, a boundary integral method developed recently is employed to investigate numerically the possible oriented transition of a globule with two unequal inner droplets in an axisymmetric microfluidic constriction. The transition is driven by an axisymmetric Poiseuille flow with a fixed volume flow rate, and the rheological behaviors of the globule are observed carefully. When the big inner droplet is initially located in the front of the globule, the maximum pressure drop during the transition is always lower than that when it is initially placed in the rear. Thus, a tropism—whereby a globule more easily gets through the constriction when its bigger inner droplet locates in its front initially—might exist, in which the orientating stimulus is the required pressure drops. The physical explanation of this phenomenon has also been analyzed in this paper.

On heat transfer in squish gaps

NASA Astrophysics Data System (ADS)

Spurk, J. H.

1986-06-01

Attention is given to the heat transfer characteristics of a squish gap in an internal combustion engine cylinder, when the piston is nearing top dead center (TDC) on the compression stroke. If the lateral extent of the gap is much larger than its height, the inviscid flow is similar to the stagnation point flow. Surface temperature and pressure histories during compression and expansion are studied. Surface temperature has a maximum near TDC, then drops and rises again during expansion; higher values are actually achieved during expansion than during compression.

Investigating Premature Ignition of Thruster Pressure Cartridges by Mechanical Impact of Internal Components

NASA Technical Reports Server (NTRS)

Woods, Stephen S.; Saulsberry, Regor

2010-01-01

Pyrotechnic thruster pressure cartridges (TPCs) are used for aeroshell separation on a new NASA crew launch vehicle. The premature ignition concern was hypothesized based on the potential range of motion of the subassemblies, projected worst case accelerations, and the internal geometry that could subject propellant grains to mechanical impact sufficiently high for ignition. This possibility was investigated by fabricating a high-fidelity model of the suspected contact geometry, placing a representative amount of propellant in it, and impacting the propellant with a range of forces equivalent to and greater than the maximum possible during launch. Testing demonstrated that the likelihood of ignition is less than 1 in 1,000,000. The test apparatus, methodology, and results are described in this paper. Nondestructive evaluation ( NDE) during TPC acceptance testing indicated that internal assemblies moved during shock and vibration testing due to an internal bond anomaly. This caused concerns that the launch environment might produce the same movement and release propellant grains that might be prematurely ignited through impact or through electrostatic discharge (ESD) as grains vibrated against internal surfaces. Since a new lot could not be fabricated in time, a determination had to be made as to whether the lot was acceptable to fly. This paper discusses the analysis and impact testing used to address the potential impact issue and a separate paper addresses the ESD issue.

Development of an Inlet Pressure Sensor for Control in a Left Ventricular Assist Device

PubMed Central

Fritz, Bryan; Cysyk, Joshua; Newswanger, Ray; Weiss, William; Rosenberg, Gerson

2010-01-01

A Tesla type continuous flow left ventricular assist device (VAD) has been designed by Penn State and Advanced Bionics, Inc. (ABI). When a continuous flow device is employed, care must be taken to limit low pressures in the ventricle that can produce an obstruction to the inlet cannula or trigger arrhythmias. Design of an inexpensive, semi-conductor strain gage inlet pressure sensor to detect suction has been completed. The research and design analysis included finite element modeling of the sensing region. Sensitivity, step-response, temperature dependence and hysteresis tests have been performed on prototype units. All sensors were able to withstand the maximum expected strain of 82 μin/in at 500 mmHg internal pressure. Average sensitivity was 0.52 ±0.24 μV/mmHg with 0.5 V excitation (n=5 units). Step response time for a 0 to 90 mmHg step change averaged 22 milliseconds. Hysteresis was measured by applying and holding 75mmHg internal pressure for 4 hours, followed by a zero pressure measurement, and ranged from -15 mmHg to 4.1 mmHg (n=3 units). Offset drift varied between 180 and -140 mmHg over a four week period. (n=2 units). Span temperature sensitivity ranged from 18 to -21 μV/°C (n=5 units). Gain temperature sensitivity ranged from -7.4 to 4.9 μV/°C (n=5 units). With the inherent drift, it is currently not possible to use the transducer to measure actual pressures, but it can easily be used to measure pressure changes throughout the cardiac cycle. This signal can then be used in the control system to avoid ventricular suction events. PMID:20335797

An investigation on effects of amputee's physiological parameters on maximum pressure developed at the prosthetic socket interface using artificial neural network.

PubMed

Nayak, Chitresh; Singh, Amit; Chaudhary, Himanshu; Unune, Deepak Rajendra

2017-10-23

Technological advances in prosthetics have attracted the curiosity of researchers in monitoring design and developments of the sockets to sustain maximum pressure without any soft tissue damage, skin breakdown, and painful sores. Numerous studies have been reported in the area of pressure measurement at the limb/socket interface, though, the relation between amputee's physiological parameters and the pressure developed at the limb/socket interface is still not studied. Therefore, the purpose of this work is to investigate the effects of patient-specific physiological parameters viz. height, weight, and stump length on the pressure development at the transtibial prosthetic limb/socket interface. Initially, the pressure values at the limb/socket interface were clinically measured during stance and walking conditions for different patients using strain gauges placed at critical locations of the stump. The measured maximum pressure data related to patient's physiological parameters was used to develop an artificial neural network (ANN) model. The effects of physiological parameters on the pressure development at the limb/socket interface were examined using the ANN model. The analyzed results indicated that the weight and stump length significantly affects the maximum pressure values. The outcomes of this work could be an important platform for the design and development of patient-specific prosthetic socket which can endure the maximum pressure conditions at stance and ambulation conditions.

A Pressure-Based Analysis of Vortex Ring Pinch-Off

NASA Astrophysics Data System (ADS)

Schlueter, Kristy; Braun, Noah; Dabiri, John

2014-11-01

This study investigated the development of vortex rings over a range of maximum stroke ratios, and analyzed vorticity and pressure data for clues to the physical mechanisms underlying vortex pinch-off. An impulsive piston velocity profile and Reynolds number of 3000 were used for all cases. The formation number was consistently found to be 3.6 +/-0.3. A recently developed algorithm was used to generate pressure fields by integrating the pressure gradient along several paths through the velocity field and taking the median to get explicit values for pressure. The formation time at the occurrence of a local maximum in the pressure between the vortex ring and the lip of the nozzle, known as the trailing pressure maximum, was found to occur concurrently with the formation number for each case, within the error associated with the temporal resolution of the data. This suggests that the trailing pressure maximum is an indicator of vortex ring pinch-off. This is consistent with the results of Lawson and Dawson (2014), who found that the appearance of the trailing pressure maximum was coincident with the formation number. This pressure based approach to determining vortex ring pinch-off will be applied to a biological flow to examine the efficiency of such a flow. This research was partially supported by the Department of Defense (DoD) through the National Defense Science & Engineering Graduate Fellowship (NDSEG) Program.

A Solar Cycle Dependence of Nonlinearity in Magnetospheric Activity

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

Johnson, Jay R; Wing, Simon

2005-03-08

The nonlinear dependencies inherent to the historical K(sub)p data stream (1932-2003) are examined using mutual information and cumulant based cost as discriminating statistics. The discriminating statistics are compared with surrogate data streams that are constructed using the corrected amplitude adjustment Fourier transform (CAAFT) method and capture the linear properties of the original K(sub)p data. Differences are regularly seen in the discriminating statistics a few years prior to solar minima, while no differences are apparent at the time of solar maximum. These results suggest that the dynamics of the magnetosphere tend to be more linear at solar maximum than at solarmore » minimum. The strong nonlinear dependencies tend to peak on a timescale around 40-50 hours and are statistically significant up to one week. Because the solar wind driver variables, VB(sub)s and dynamical pressure exhibit a much shorter decorrelation time for nonlinearities, the results seem to indicate that the nonlinearity is related to internal magnetospheric dynamics. Moreover, the timescales for the nonlinearity seem to be on the same order as that for storm/ring current relaxation. We suggest that the strong solar wind driving that occurs around solar maximum dominates the magnetospheric dynamics suppressing the internal magnetospheric nonlinearity. On the other hand, in the descending phase of the solar cycle just prior to solar minimum, when magnetospheric activity is weaker, the dynamics exhibit a significant nonlinear internal magnetospheric response that may be related to increased solar wind speed.« less

14 CFR 25.365 - Pressurized compartment loads.

Code of Federal Regulations, 2010 CFR

2010-01-01

... Pressurized compartment loads. For airplanes with one or more pressurized compartments the following apply: (a... differential loads from zero up to the maximum relief valve setting. (b) The external pressure distribution in... zero up to the maximum allowed during landing. (d) The airplane structure must be designed to be able...

46 CFR 151.50-13 - Propylene oxide.

Code of Federal Regulations, 2012 CFR

2012-10-01

...) Pressure vessel cargo tanks shall meet the requirements of Class II pressure vessels. (2) Cargo tanks shall be designed for the maximum pressure expected to be encountered during loading, storing and... cargo piping shall be subjected to a hydrostatic test of 11/2 times the maximum pressure to which they...

46 CFR 151.50-13 - Propylene oxide.

Code of Federal Regulations, 2014 CFR

2014-10-01

...) Pressure vessel cargo tanks shall meet the requirements of Class II pressure vessels. (2) Cargo tanks shall be designed for the maximum pressure expected to be encountered during loading, storing and... cargo piping shall be subjected to a hydrostatic test of 11/2 times the maximum pressure to which they...

46 CFR 151.50-13 - Propylene oxide.

Code of Federal Regulations, 2010 CFR

2010-10-01

...) Pressure vessel cargo tanks shall meet the requirements of Class II pressure vessels. (2) Cargo tanks shall be designed for the maximum pressure expected to be encountered during loading, storing and... cargo piping shall be subjected to a hydrostatic test of 11/2 times the maximum pressure to which they...

46 CFR 151.50-13 - Propylene oxide.

Code of Federal Regulations, 2013 CFR

2013-10-01

...) Pressure vessel cargo tanks shall meet the requirements of Class II pressure vessels. (2) Cargo tanks shall be designed for the maximum pressure expected to be encountered during loading, storing and... cargo piping shall be subjected to a hydrostatic test of 11/2 times the maximum pressure to which they...

46 CFR 151.50-13 - Propylene oxide.

Code of Federal Regulations, 2011 CFR

2011-10-01

...) Pressure vessel cargo tanks shall meet the requirements of Class II pressure vessels. (2) Cargo tanks shall be designed for the maximum pressure expected to be encountered during loading, storing and... cargo piping shall be subjected to a hydrostatic test of 11/2 times the maximum pressure to which they...

Analysis and Design of the NASA Langley Cryogenic Pressure Box

NASA Technical Reports Server (NTRS)

Glass, David E.; Stevens, Jonathan C.; Vause, R. Frank; Winn, Peter M.; Maguire, James F.; Driscoll, Glenn C.; Blackburn, Charles L.; Mason, Brian H.

1999-01-01

A cryogenic pressure box was designed and fabricated for use at NASA Langley Research Center (LaRC) to subject 72 in. x 60 in. curved panels to cryogenic temperatures and biaxial tensile loads. The cryogenic pressure box is capable of testing curved panels down to -423 F (20K) with 54 psig maximum pressure on the concave side, and elevated temperatures and atmospheric pressure on the convex surface. The internal surface of the panel is cooled by high pressure helium as that is cooled to -423 F by liquid helium heat exchangers. An array of twelve independently controlled fans circulate the high pressure gaseous helium to provide uniform cooling on the panel surface. The load introduction structure, consisting of four stainless steel load plates and numerous fingers attaching the load plates to the test panel, is designed to introduce loads into the test panel that represent stresses that will he observed in the actual tank structure. The load plates are trace cooled with liquid nitrogen to reduce thermal gradients that may result in bending the load plates, and thus additional stresses in the test panel. The design of the cryogenic systems, load introduction structure, and control system are discussed in this report.

Parametric study of a simultaneous pitch/yaw thrust vectoring single expansion ramp nozzle

NASA Technical Reports Server (NTRS)

Schirmer, Alberto W.; Capone, Francis J.

1989-01-01

In the course of the last eleven years, the concept of thrust vectoring has emerged as a promising method of enhancing aircraft control capabilities in post-stall flight incursions during combat. In order to study the application of simultaneous pitch and yaw vectoring to single expansion ramp nozzles, a static test was conducted in the NASA-Langley 16 foot transonic tunnel. This investigation was based on internal performance data provided by force, mass flow and internal pressure measurements at nozzle pressure ratios up to 8. The internal performance characteristics of the nozzle were studied for several combinations of six different parameters: yaw vectoring angle, pitch vectoring angle, upper ramp cutout, sidewall hinge location, hinge inclination angle and sidewall containment. Results indicated a 2-to- 3-percent decrease in resultant thrust ratio with vectoring in either pitch or yaw. Losses were mostly associated with the turning of supersonic flow. Resultant thrust ratios were also decreased by sideways expansion of the jet. The effects of cutback corners in the upper ramp and lower flap on performance were small. Maximum resultant yaw vector angles, about half of the flap angle, were achieved for the configuration with the most forward hinge location.

Capturing Pressure Oscillations in Numerical Simulations of Internal Combustion Engines

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

Gubba, Sreenivasa Rao; Jupudi, Ravichandra S.; Pasunurthi, Shyam Sundar

In an earlier publication, the authors compared numerical predictions of the mean cylinder pressure of diesel and dual-fuel combustion, to that of measured pressure data from a medium-speed, large-bore engine. In these earlier comparisons, measured data from a flush-mounted in-cylinder pressure transducer showed notable and repeatable pressure oscillations which were not evident in the mean cylinder pressure predictions from computational fluid dynamics (CFD). In this paper, the authors present a methodology for predicting and reporting the local cylinder pressure consistent with that of a measurement location. Such predictions for large-bore, medium-speed engine operation demonstrate pressure oscillations in accordance with thosemore » measured. The temporal occurrences of notable pressure oscillations were during the start of combustion and around the time of maximum cylinder pressure. With appropriate resolutions in time steps and mesh sizes, the local cell static pressure predicted for the transducer location showed oscillations in both diesel and dual-fuel combustion modes which agreed with those observed in the experimental data. Fast Fourier transform (FFT) analysis on both experimental and calculated pressure traces revealed that the CFD predictions successfully captured both the amplitude and frequency range of the oscillations. Furthermore, resolving propagating pressure waves with the smaller time steps and grid sizes necessary to achieve these results required a significant increase in computer resources.« less

Capturing Pressure Oscillations in Numerical Simulations of Internal Combustion Engines

DOE PAGES

Gubba, Sreenivasa Rao; Jupudi, Ravichandra S.; Pasunurthi, Shyam Sundar; ...

2018-04-09

In an earlier publication, the authors compared numerical predictions of the mean cylinder pressure of diesel and dual-fuel combustion, to that of measured pressure data from a medium-speed, large-bore engine. In these earlier comparisons, measured data from a flush-mounted in-cylinder pressure transducer showed notable and repeatable pressure oscillations which were not evident in the mean cylinder pressure predictions from computational fluid dynamics (CFD). In this paper, the authors present a methodology for predicting and reporting the local cylinder pressure consistent with that of a measurement location. Such predictions for large-bore, medium-speed engine operation demonstrate pressure oscillations in accordance with thosemore » measured. The temporal occurrences of notable pressure oscillations were during the start of combustion and around the time of maximum cylinder pressure. With appropriate resolutions in time steps and mesh sizes, the local cell static pressure predicted for the transducer location showed oscillations in both diesel and dual-fuel combustion modes which agreed with those observed in the experimental data. Fast Fourier transform (FFT) analysis on both experimental and calculated pressure traces revealed that the CFD predictions successfully captured both the amplitude and frequency range of the oscillations. Furthermore, resolving propagating pressure waves with the smaller time steps and grid sizes necessary to achieve these results required a significant increase in computer resources.« less

Evolution of Magnetized Liner Inertial Fusion (MagLIF) Targets

DOE PAGES

Fooks, J. A.; Carlson, L. C.; Fitzsimmons, P.; ...

2017-12-19

Here, the magnetized liner inertial fusion (MagLIF) experimental campaign conducted at the University of Rochester’s Laboratory for Laser Energetics (LLE) has evolved significantly since its start in 2014. Scientific requirements and OMEGA EP system technology both have progressed, resulting in necessary and available updates to the target design. These include, but are not limited to: optimizing target dimensions and aspect ratios to maximize survival at desired pressures; coating target components to enhance physics diagnosis; precision-machining diagnostic windows along the axis of the target; improving fiducial placement reproducibility and reducing subsequent assembly time by 50%; and implementing gas-pressure transducers on themore » targets. In addition, target fabrication techniques have changed and improved, allowing for simpler target reproducibility and decreased assembly time. To date, eleven variations of targets have been fabricated, with successful target fielding ranging from 1 to 20atm internal pressure and a maximum survivability of 33atm.« less

Preferential vibrational excitation in microwave nitrogen plasma assessed by Raman scattering

NASA Astrophysics Data System (ADS)

Gatti, N.; Ponduri, S.; Peeters, F. J. J.; van den Bekerom, D. C. M.; Minea, T.; Tosi, P.; van de Sanden, M. C. M.; van Rooij, G. J.

2018-05-01

Vibrational activation of N2 molecules in a flowing microwave plasma is investigated in the context of utilising electrical energy for chemical conversion. Spatial profiles of rotational (T r ) and vibrational (T v ) temperatures are measured by Raman scattering. Maximum values of T r = 3500 K and T v = 6000 K were observed in the centre of the plasma at low pressure (50 mbar). A detailed quantification of the local energy content shows how the strong non-equilibrium character of low pressure discharges compares with a closer-to-equilibrium energy distribution at higher pressures. Measurements performed downstream of the plasma display the ability of the microwave flowing reactor to deliver up to 48% of the specific energy input (SEI) into internal degrees of freedom of the gas molecules. Specifically, 23% of the SEI is loaded into the vibrational mode, which is potentially available to enhance chemical reactivity of endothermic reactions.

Evolution of Magnetized Liner Inertial Fusion (MagLIF) Targets

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

Fooks, J. A.; Carlson, L. C.; Fitzsimmons, P.

Here, the magnetized liner inertial fusion (MagLIF) experimental campaign conducted at the University of Rochester’s Laboratory for Laser Energetics (LLE) has evolved significantly since its start in 2014. Scientific requirements and OMEGA EP system technology both have progressed, resulting in necessary and available updates to the target design. These include, but are not limited to: optimizing target dimensions and aspect ratios to maximize survival at desired pressures; coating target components to enhance physics diagnosis; precision-machining diagnostic windows along the axis of the target; improving fiducial placement reproducibility and reducing subsequent assembly time by 50%; and implementing gas-pressure transducers on themore » targets. In addition, target fabrication techniques have changed and improved, allowing for simpler target reproducibility and decreased assembly time. To date, eleven variations of targets have been fabricated, with successful target fielding ranging from 1 to 20atm internal pressure and a maximum survivability of 33atm.« less

40 CFR 60.116b - Monitoring of operations.

Code of Federal Regulations, 2012 CFR

2012-07-01

... greater than or equal to 151 m3 storing a liquid with a maximum true vapor pressure greater than or equal... liquid with a maximum true vapor pressure greater than or equal to 15.0 kPa shall maintain a record of... than or equal to 75 m3 but less than 151 m3 storing a liquid with a maximum true vapor pressure that is...

40 CFR 60.116b - Monitoring of operations.

Code of Federal Regulations, 2014 CFR

2014-07-01

... greater than or equal to 151 m3 storing a liquid with a maximum true vapor pressure greater than or equal... liquid with a maximum true vapor pressure greater than or equal to 15.0 kPa shall maintain a record of... than or equal to 75 m3 but less than 151 m3 storing a liquid with a maximum true vapor pressure that is...

40 CFR 60.116b - Monitoring of operations.

Code of Federal Regulations, 2011 CFR

2011-07-01

... greater than or equal to 151 m3 storing a liquid with a maximum true vapor pressure greater than or equal... liquid with a maximum true vapor pressure greater than or equal to 15.0 kPa shall maintain a record of... than or equal to 75 m3 but less than 151 m3 storing a liquid with a maximum true vapor pressure that is...

40 CFR 60.116b - Monitoring of operations.

Code of Federal Regulations, 2013 CFR

2013-07-01

... greater than or equal to 151 m3 storing a liquid with a maximum true vapor pressure greater than or equal... liquid with a maximum true vapor pressure greater than or equal to 15.0 kPa shall maintain a record of... than or equal to 75 m3 but less than 151 m3 storing a liquid with a maximum true vapor pressure that is...

Levels of maximum end-expiratory carbon monoxide and certain cardiovascular parameters following hubble-bubble smoking.

PubMed

Shafagoj, Yanal A; Mohammed, Faisal I

2002-08-01

The physiological effects of cigarette smoking have been widely studied, however, little is known regarding the effects of smoking hubble-bubble. We examined the acute effects of hubble-bubble smoking on heart rate, systolic, diastolic, and mean arterial blood pressure and maximum end-expiratory carbon monoxide. This study was carried out in the student laboratory, School of Medicine, Department of Physiology, University of Jordan, Amman, Jordan, during the summer of 1999. In 18 healthy habitual hubble-bubble smokers, heart rate, blood pressure, and maximum end-expiratory carbon monoxide was measured before, during and post smoking of one hubble-bubble run (45 minutes). Compared to base line (time zero), at the end of smoking heart rate, systolic blood pressure, diastolic blood pressure, mean arterial blood pressure, and maximum end-expiratory carbon monoxide were increased 16 2.4 beats per minute, 6.7 2.5 mm Hg, 4.4 1.6 mm Hg, 5.2 1.7 mm Hg, and 14.2 1.8 ppm, (mean standard error of mean, P<.05). Acute short-term active hubble-bubble smoking elicits a modest increase in heart rate, systolic blood pressure, diastolic blood pressure, mean arterial blood pressure and maximum end-expiratory carbon monoxide in healthy hubble-bubble smokers.

Enhanced oil recovery using flash-driven steamflooding

DOEpatents

Roark, Steven D.

1990-01-01

The present invention is directed to a novel steamflooding process which utilizes three specific stages of steam injection for enhanced oil recovery. The three stages are as follows: As steam is being injected into an oil-bearing reservoir through an injection well, the production rate of a production well located at a distance from the injection well is gradually restricted to a point that the pressure in the reservoir increases at a predetermined rate to a predetermined maximum value. After the maximum pressure has been reached, the production rate is increased to a value such that the predetermined maximum pressure value is maintained. Production at maximum pressure is continued for a length of time that will be unique for each individual reservoir. In some cases, this step of the steamflooding process of the invention may be omitted entirely. In the third stage of the steamflooding process of the invention, production rates at the producing well are increased gradually to allow the pressure to decrease down from the maximum pressure value to the original pressure value at the producing well. The rate of pressure reduction will be unique for each reservoir. After completing stage three, the three stages can be repeated or the steamflood may be terminated as considered desirable.

Comparison of masticatory performance and tongue pressure between children and young adults.

PubMed

Fujita, Yuko; Ichikawa, Maika; Hamaguchi, Ayako; Maki, Kenshi

2018-04-01

The aims of the present study were to evaluate whether there are significant differences in masticatory performance by gender and dental stage. We also determined the factors directly associated with the masticatory performance in children, and those directly associated with masticatory performance in young adults. The study included 180 subjects, ranging in age from 6 to 12 years or 20 to 33 years. The subjects were divided into three groups according to the Hellman developmental stage (III A, III B, or VA); the groups were the subdivided according to gender. The body mass index (BMI), maximum tongue pressure, and sum of decayed, missing, and filled teeth (DMFT) were determined in all subjects. To investigate masticatory performance, the total number and maximum projected area of chewed particles of the jelly materials were measured. Masticatory performance had the highest values at Stage VA in both males and females. Regarding the maximum tongue pressure in females, Stage III B had the highest value of all stages. Multiple regression analysis showed that masticatory performance was associated with DMFT index, maximum tongue pressure, and BMI in children. Among young adults, masticatory performance was associated with DMFT index and maximum tongue pressure. Better masticatory performance is directly associated with better dental status, a higher BMI, and tongue pressure in schoolchildren. Additionally, masticatory performance was well-correlated with tongue pressure in young adults, although maximum tongue pressure reached its peak before Stage VA in females. We suggest that females need training with respect to tongue pressure, by the mixed dentition stage.

Aero-Thermo-Structural Design Optimization of Internally Cooled Turbine Blades

NASA Technical Reports Server (NTRS)

Dulikravich, G. S.; Martin, T. J.; Dennis, B. H.; Lee, E.; Han, Z.-X.

1999-01-01

A set of robust and computationally affordable inverse shape design and automatic constrained optimization tools have been developed for the improved performance of internally cooled gas turbine blades. The design methods are applicable to the aerodynamics, heat transfer, and thermoelasticity aspects of the turbine blade. Maximum use of the existing proven disciplinary analysis codes is possible with this design approach. Preliminary computational results demonstrate possibilities to design blades with minimized total pressure loss and maximized aerodynamic loading. At the same time, these blades are capable of sustaining significantly higher inlet hot gas temperatures while requiring remarkably lower coolant mass flow rates. These results suggest that it is possible to design internally cooled turbine blades that will cost less to manufacture, will have longer life span, and will perform as good, if not better than, film cooled turbine blades.

Volumetric properties under pressure for 1,2-dichlorofluoroethane (R141), 1-fluoro-1,1,2-trichloroethane (R131a), and 1,2-dichloro-1,1-difluoroethane (R132b)

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

Malhotra, R.; Woolf, L.A.

1997-01-01

The effect of pressure on the volume of R141, R131, and R132b is reported as volume ratios (the volume under pressure relative to its value at atmospheric pressure) at six temperatures covering the range 278.15 to 338.13 K and pressures up to 380 MPa for R141 and R131a. For R132b the same temperature range has been used, but above its normal boiling point experimental arrangements have limited maximum pressures to below 300 MPa, with some loss of accuracy. Densities have been measured at atmospheric pressure for each liquid. The experimental data have been used to calculate isothermal compressibilities, thermal expansivities,more » and internal pressures; the change in isobaric heat capacity from its value at atmospheric pressure has also been estimated. The volume ratios for all three compounds can be represented by a version of the Tait equation based on previously reported data for 1,2-dichloroethane and 1,1,2-trichloroethane with the inclusion of allowances of the substitution in the former of chlorine or fluorine for the hydrogens on one of the carbons.« less

Altitude-Related Change in Endotracheal Tube Cuff Pressures in Helicopter EMS

PubMed Central

Weisberg, Stacy N.; McCall, Jonathan C.; Tennyson, Joseph

2017-01-01

Introduction Over-inflation of endotracheal tube (ETT) cuffs has the potential to lead to scarring and stenosis of the trachea.1, 2,3, 4 The air inside an ETT cuff is subject to expansion as atmospheric pressure decreases, as happens with an increase in altitude. Emergency medical services helicopters are not pressurized, thereby providing a good environment for studying the effects of altitude changes ETT cuff pressures. This study aims to explore the relationship between altitude and ETT cuff pressures in a helicopter air-medical transport program. Methods ETT cuffs were initially inflated in a nonstandardized manner and then adjusted to a pressure of 25 cmH2O. The pressure was again measured when the helicopter reached maximum altitude. A final pressure was recorded when the helicopter landed at the receiving facility. Results We enrolled 60 subjects in the study. The mean for initial tube cuff pressures was 70 cmH2O. Maximum altitude for the program ranged from 1,000–3,000 feet above sea level, with a change in altitude from 800–2,480 feet. Mean cuff pressure at altitude was 36.52 ± 8.56 cmH2O. Despite the significant change in cuff pressure at maximum altitude, there was no relationship found between the maximum altitude and the cuff pressures measured. Conclusion Our study failed to demonstrate the expected linear relationship between ETT cuff pressures and the maximum altitude achieved during typical air-medical transportation in our system. At altitudes less than 3,000 feet above sea level, the effect of altitude change on ETT pressure is minimal and does not require a change in practice to saline-filled cuffs. PMID:28611883

Altitude-Related Change in Endotracheal Tube Cuff Pressures in Helicopter EMS.

PubMed

Weisberg, Stacy N; McCall, Jonathan C; Tennyson, Joseph

2017-06-01

Over-inflation of endotracheal tube (ETT) cuffs has the potential to lead to scarring and stenosis of the trachea.1, 2,3, 4 The air inside an ETT cuff is subject to expansion as atmospheric pressure decreases, as happens with an increase in altitude. Emergency medical services helicopters are not pressurized, thereby providing a good environment for studying the effects of altitude changes ETT cuff pressures. This study aims to explore the relationship between altitude and ETT cuff pressures in a helicopter air-medical transport program. ETT cuffs were initially inflated in a nonstandardized manner and then adjusted to a pressure of 25 cmH 2 O. The pressure was again measured when the helicopter reached maximum altitude. A final pressure was recorded when the helicopter landed at the receiving facility. We enrolled 60 subjects in the study. The mean for initial tube cuff pressures was 70 cmH 2 O. Maximum altitude for the program ranged from 1,000-3,000 feet above sea level, with a change in altitude from 800-2,480 feet. Mean cuff pressure at altitude was 36.52 ± 8.56 cmH 2 O. Despite the significant change in cuff pressure at maximum altitude, there was no relationship found between the maximum altitude and the cuff pressures measured. Our study failed to demonstrate the expected linear relationship between ETT cuff pressures and the maximum altitude achieved during typical air-medical transportation in our system. At altitudes less than 3,000 feet above sea level, the effect of altitude change on ETT pressure is minimal and does not require a change in practice to saline-filled cuffs.

Impact of abutment rotation and angulation on marginal fit: theoretical considerations.

PubMed

Semper, Wiebke; Kraft, Silvan; Mehrhof, Jurgen; Nelson, Katja

2010-01-01

Rotational freedom of various implant positional index designs has been previously calculated. To investigate its clinical relevance, a three-dimensional simulation was performed to demonstrate the influence of rotational displacements of the abutment on the marginal fit of prosthetic superstructures. Idealized abutments with different angulations (0, 5, 10, 15, and 20 degrees) were virtually constructed (SolidWorks Office Premium 2007). Then, rotational displacement was simulated with various degrees of rotational freedom (0.7, 0.95, 1.5, 1.65, and 1.85 degrees). The resulting horizontal displacement of the abutment from the original position was quantified in microns, followed by a simulated pressure-less positioning of superstructures with defined internal gaps (5 µm, 60 µm, and 100 µm). The resulting marginal gap between the abutment and the superstructure was measured vertically with the SolidWorks measurement tool. Rotation resulted in a displacement of the abutment of up to 157 µm at maximum rotation and angulation. Interference of a superstructure with a defined internal gap of 5 µm placed on the abutment resulted in marginal gaps up to 2.33 mm at maximum rotation and angulation; with a 60-µm internal gap, the marginal gaps reached a maximum of 802 µm. Simulation using a superstructure with an internal gap of 100 µm revealed a marginal gap of 162 µm at abutment angulation of 20 degrees and rotation of 1.85 degrees. The marginal gaps increased with the degree of abutment angulation and the extent of rotational freedom. Rotational displacement of the abutment influenced prosthesis misfit. The marginal gaps between the abutment and the superstructure increased with the rotational freedom of the index and the angulation of the abutment.

Design, Development and Testing of Inconel Alloy IN718 Spherical Gas Bottle for Oxygen Storage

NASA Astrophysics Data System (ADS)

Chenna Krishna, S.; Agilan, M.; Sudarshan Rao, G.; Singh, Satish Kumar; Narayana Murty, S. V. S.; Venkata Narayana, Ganji; Beena, A. P.; Rajesh, L.; Jha, Abhay K.; Pant, Bhanu

2017-11-01

This paper describes the details of design, manufacture and testing of 200 mm diameter spherical gas bottle of Inconel 718 (IN718) with nominal wall thickness of 2.3 mm. Gas bottle was designed for the specified internal pressure loading with a thickness of 2.9 mm at the circumferential weld which was brought down to 2.3 mm at the membrane locations. Hemispherical forgings produced through closed-die hammer forging were machined and electron beam welded to produce a spherical gas bottle. Duly welded gas bottle was subjected to standard aging treatment to achieve the required tensile strength. Aged gas bottle was inspected for dimensions and other stringent quality requirements using various nondestructive testing techniques. After inspection, gas bottle was subjected to pressure test for maximum expected operating pressure and proof pressure of 25 and 37.5 MPa, respectively. Strain gauges were bonded at different locations on the gas bottle to monitor the strains during the pressure test and correlated with the predicted values. The predicted strain matched well with the experimental strain confirming the design and structural integrity.

A Study of the Response of the Human Cadaver Head to Impact

PubMed Central

Hardy, Warren N.; Mason, Matthew J.; Foster, Craig D.; Shah, Chirag S.; Kopacz, James M.; Yang, King H.; King, Albert I.; Bishop, Jennifer; Bey, Michael; Anderst, William; Tashman, Scott

2008-01-01

High-speed biplane x-ray and neutral density targets were used to examine brain displacement and deformation during impact. Relative motion, maximum principal strain, maximum shear strain, and intracranial pressure were measured in thirty-five impacts using eight human cadaver head and neck specimens. The effect of a helmet was evaluated. During impact, local brain tissue tends to keep its position and shape with respect to the inertial frame, resulting in relative motion between the brain and skull and deformation of the brain. The local brain motions tend to follow looping patterns. Similar patterns are observed for impact in different planes, with some degree of posterior-anterior and right-left symmetry. Peak coup pressure and pressure rate increase with increasing linear acceleration, but coup pressure pulse duration decreases. Peak average maximum principal strain and maximum shear are on the order of 0.09 for CFC 60 Hz data for these tests. Peak average maximum principal strain and maximum shear increase with increasing linear acceleration, coup pressure, and coup pressure rate. Linear and angular acceleration of the head are reduced with use of a helmet, but strain increases. These results can be used for the validation of finite element models of the human head. PMID:18278591

Lack of validation of the Dixtal (DX 2020) upper arm blood pressure monitor, in oscillometric mode, for clinical use in an intensive care unit, according to the European Society of Hypertension-International Protocol revision 2010.

PubMed

Gothardo, Ana C L O; Savioli, Amanda F; Santos, Dayanna S; Lamas, José L T

2013-08-01

The aim of the study was to evaluate the accuracy of the oscillometric blood pressure section in the DX 2020 Dixtal multiparametric monitor in adults according to the European Society of Hypertension-International Protocol as revised in 2010 (ESH-IP 2010). The blood pressure was sequentially verified in 33 individuals admitted to an adult ICU (18 men, mean age 44 years) with a mercury column sphygmomanometer (two observers) and the DX 2020 test device (one supervisor). Ninety-nine pairs of differences were obtained. Data analysis followed the ESH-IP 2010 requirements. In the first requirement, the DX 2020 device failed in the validation study in the 5, 10, and 15 mmHg ranges. From the 99 pairs of differences, only 43/73, 69/87, and 81/96 were obtained for systolic blood pressure and 29/65, 56/81, and 71/93 were obtained for diastolic blood pressure. In the second requirement, at least 24 individuals should have, from their comparisons, two under 0-5 mmHg ranges, which was observed only with 16 individuals in the systolic and nine in the diastolic range. Moreover, at maximum, only three readings could have differences of more than 5 mmHg, and this was observed in 10 individuals in the systolic range and 17 individuals in the diastolic range. The DX 2020 automatic multiparametric monitor for blood pressure measurement has not been recommended for clinical use according to the ESH-IP 2010. It is important to highlight that this work refers only to a blood pressure measurement module and that the same conclusion cannot be drawn for its other functions.

Exhaust-Gas Pressure and Temperature Survey of F404-GE-400 Turbofan Engine

NASA Technical Reports Server (NTRS)

Walton, James T.; Burcham, Frank W., Jr.

1986-01-01

An exhaust-gas pressure and temperature survey of the General Electric F404-GE-400 turbofan engine was conducted in the altitude test facility of the NASA Lewis Propulsion System Laboratory. Traversals by a survey rake were made across the exhaust-nozzle exit to measure the pitot pressure and total temperature. Tests were performed at Mach 0.87 and a 24,000-ft altitude and at Mach 0.30 and a 30,000-ft altitude with various power settings from intermediate to maximum afterburning. Data yielded smooth pressure and temperature profiles with maximum jet temperatures approximately 1.4 in. inside the nozzle edge and maximum jet temperatures from 1 to 3 in. inside the edge. A low-pressure region located exactly at engine center was noted. The maximum temperature encountered was 3800 R.

Fluorescence Imaging Study of Impinging Underexpanded Jets

NASA Technical Reports Server (NTRS)

Inman, Jennifer A.; Danehy, Paul M.; Nowak, Robert J.; Alderfer, David W.

2008-01-01

An experiment was designed to create a simplified simulation of the flow through a hole in the surface of a hypersonic aerospace vehicle and the subsequent impingement of the flow on internal structures. In addition to planar laser-induced fluorescence (PLIF) flow visualization, pressure measurements were recorded on the surface of an impingement target. The PLIF images themselves provide quantitative spatial information about structure of the impinging jets. The images also help in the interpretation of impingement surface pressure profiles by highlighting the flow structures corresponding to distinctive features of these pressure profiles. The shape of the pressure distribution along the impingement surface was found to be double-peaked in cases with a sufficiently high jet-exit-to-ambient pressure ratio so as to have a Mach disk, as well as in cases where a flow feature called a recirculation bubble formed at the impingement surface. The formation of a recirculation bubble was in turn found to depend very sensitively upon the jet-exit-to-ambient pressure ratio. The pressure measured at the surface was typically less than half the nozzle plenum pressure at low jet pressure ratios and decreased with increasing jet pressure ratios. Angled impingement cases showed that impingement at a 60deg angle resulted in up to a factor of three increase in maximum pressure at the plate compared to normal incidence.

The coronal structure of active regions

NASA Technical Reports Server (NTRS)

Landini, M.; Monsignori Fossi, B. C.; Krieger, A.; Vaiana, G. S.

1975-01-01

A four-parameter model, which assumes a Gaussian dependence of both temperature and pressure on distance from center, is used to fit the compact part of coronal active regions as observed in X-ray photographs from a rocket experiment. The four parameters are the maximum temperature, the maximum pressure, the width of the pressure distribution, and the width of the temperature distribution. The maximum temperature ranges from 2.2 to 2.8 million K, and the maximum density from 2 to 9 by 10 to the 9th power per cu cm. The range of the pressure-distribution width is from 2 to 4 by 10 to the 9th power cm and that of the temperature-distribution width from 2 to 7.

Superplastic Forming of Duplex Stainless Steel for Aerospace Part

NASA Astrophysics Data System (ADS)

Lee, Ho-Sung; Yoon, Jong-Hoon; Yoo, Joon-Tae; Yi, Young-Moo

2011-08-01

In this study, the high temperature forming behavior of duplex stainless steel has been characterized and the outer shell of a combustion chamber was fabricated with pressure difference of hot gas. It consists of two parts which are the outer skin made of stainless steel to sustain the internal pressure and the inner shell made of copper alloy for regenerative cooling channels. Two outer skins partitioned to half with respect to the symmetric axis was prepared by hot gas forming process with a maximum pressure of 7 MPa following to FEM analysis. For inner layer, copper alloy was machined for cooling channels and then placed in the gas pressure welding fixture. It is shown that the optimum condition of gas pressure welding is 7 MPa at 890 °C, for one hour. EDX analysis and scanning electron microscope micrograph confirm the atomic diffusion process is observed at the interface and copper atoms diffuse into steel, while iron and chrome atoms diffuse into copper. The result shows that the manufacturing method with superplastic forming and gas pressure welding of steel and copper alloy has been successful for near net shape manufacturing of scaled combustion chamber of launch vehicle.

Simulation of heat and mass transfer processes in the experimental section of the air-condensing unit of Scientific Production Company "Turbocon"

NASA Astrophysics Data System (ADS)

Artemov, V. I.; Minko, K. B.; Yan'kov, G. G.; Kiryukhin, A. V.

2016-05-01

A mathematical model was developed to be used for numerical analysis of heat and mass transfer processes in the experimental section of the air condenser (ESAC) created in the Scientific Production Company (SPC) "Turbocon" and mounted on the territory of the All-Russia Thermal Engineering Institute. The simulations were performed using the author's CFD code ANES. The verification of the models was carried out involving the experimental data obtained in the tests of ESAC. The operational capability of the proposed models to calculate the processes in steam-air mixture and cooling air and algorithms to take into account the maldistribution in the various rows of tube bundle was shown. Data on the influence of temperature and flow rate of the cooling air on the pressure in the upper header of ESAC, effective heat transfer coefficient, steam flow distribution by tube rows, and the dimensions of the ineffectively operating zones of tube bundle for two schemes of steam-air mixture flow (one-pass and two-pass ones) were presented. It was shown that the pressure behind the turbine (in the upper header) increases significantly at increase of the steam flow rate and reduction of the flow rate of cooling air and its temperature rise, and the maximum value of heat transfer coefficient is fully determined by the flow rate of cooling air. Furthermore, the steam flow rate corresponding to the maximum value of heat transfer coefficient substantially depends on the ambient temperature. The analysis of the effectiveness of the considered schemes of internal coolant flow was carried out, which showed that the two-pass scheme is more effective because it provides lower pressure in the upper header, despite the fact that its hydraulic resistance at fixed flow rate of steam-air mixture is considerably higher than at using the one-pass schema. This result is a consequence of the fact that, in the two-pass scheme, the condensation process involves the larger internal surface of tubes, results in lower values of Δ t (the temperature difference between internal and external coolant) for a given heat load.

Sound field inside acoustically levitated spherical drop

NASA Astrophysics Data System (ADS)

Xie, W. J.; Wei, B.

2007-05-01

The sound field inside an acoustically levitated small spherical water drop (radius of 1mm) is studied under different incident sound pressures (amplitude p0=2735-5643Pa). The transmitted pressure ptr in the drop shows a plane standing wave, which varies mainly in the vertical direction, and distributes almost uniformly in the horizontal direction. The maximum of ptr is always located at the lowermost point of the levitated drop. Whereas the secondary maximum appears at the uppermost point if the incident pressure amplitude p0 is higher than an intermediate value (3044Pa), in which there exists a pressure nodal surface in the drop interior. The value of the maximum ptr lies in a narrow range of 2489-3173Pa, which has a lower limit of 2489Pa when p0=3044Pa. The secondary maximum of ptr is rather small and only remarkable at high incident pressures.

Comparison of shoulder internal rotation test with the elbow flexion test in the diagnosis of cubital tunnel syndrome.

PubMed

Ochi, Kensuke; Horiuchi, Yukio; Tanabe, Aya; Morita, Kozo; Takeda, Kentaro; Ninomiya, Ken

2011-05-01

To compare the shoulder internal rotation test-a new, provocative test-with the elbow flexion test in the diagnosis of cubital tunnel syndrome (CubTS). Twenty-five patients with CubTS were examined before and after surgery with 10 seconds each of the elbow flexion and shoulder internal rotation tests. Fifty-four asymptomatic individuals and 14 neuropathy patients with a diagnosis other than CubTS were also examined as control cases. For the shoulder internal rotation test, the patient's upper extremity was kept at 90° abduction, maximum internal rotation, and 10° flexion at the shoulder, with 90° elbow flexion and neutral position of the forearm and wrist, with finger extension. Test results were considered positive if any slight symptom attributable to CubTS occurred within 10 seconds. Extraneural pressure inside the cubital tunnel was intraoperatively measured with the positions of both the elbow flexion and shoulder internal rotation tests, in 15 of the CubTS cases. Statistical analyses were performed using Student's t-test with a confidence level of 95%. The preoperative sensitivity in CubTS cases was 80% in the 10-second shoulder internal rotation test and 36% in the 10-second elbow flexion test, and these differences were significant. None of the control cases had positive results in either test. All the CubTS cases improved with surgery; after surgery, neither test provoked symptoms in any surgical patient. The extraneural pressure increased in both provocative positions with no significant difference. Positive results for the 10-second shoulder internal rotation test were more sensitive than that for the elbow flexion test of the same duration and seemed specific to CubTS. Copyright © 2011 American Society for Surgery of the Hand. Published by Elsevier Inc. All rights reserved.

40 CFR Table 4 to Subpart Ooo of... - Operating Parameter Levels

Code of Federal Regulations, 2012 CFR

2012-07-01

... temperature Maximum temperature Carbon absorber Total regeneration steam or nitrogen flow, or pressure (gauge or absolute) a during carbon bed regeneration cycle; and temperature of the carbon bed after regeneration (and within 15 minutes of completing any cooling cycle(s)) Maximum flow or pressure; and maximum...

46 CFR 28.880 - Hydraulic equipment.

Code of Federal Regulations, 2011 CFR

2011-10-01

... times the system's maximum operating pressure. (c) Each hydraulic system must be equipped with at least... sudden loss of control due to loss of hydraulic system pressure. A system is considered to be fail-safe... catalog number and maximum allowable working pressure. (k) Existing hydraulic piping, nonmetallic hose...

46 CFR 28.880 - Hydraulic equipment.

Code of Federal Regulations, 2013 CFR

2013-10-01

... times the system's maximum operating pressure. (c) Each hydraulic system must be equipped with at least... sudden loss of control due to loss of hydraulic system pressure. A system is considered to be fail-safe... catalog number and maximum allowable working pressure. (k) Existing hydraulic piping, nonmetallic hose...

46 CFR 28.880 - Hydraulic equipment.

Code of Federal Regulations, 2014 CFR

2014-10-01

... times the system's maximum operating pressure. (c) Each hydraulic system must be equipped with at least... sudden loss of control due to loss of hydraulic system pressure. A system is considered to be fail-safe... catalog number and maximum allowable working pressure. (k) Existing hydraulic piping, nonmetallic hose...

46 CFR 28.880 - Hydraulic equipment.

Code of Federal Regulations, 2012 CFR

2012-10-01

... times the system's maximum operating pressure. (c) Each hydraulic system must be equipped with at least... sudden loss of control due to loss of hydraulic system pressure. A system is considered to be fail-safe... catalog number and maximum allowable working pressure. (k) Existing hydraulic piping, nonmetallic hose...

Improved spectrophotometric cell for hydrothermal solutions

USGS Publications Warehouse

Susak, N.J.; Crerar, D.A.; Forseman, T.C.; Haas, J.L.

1981-01-01

A simple, inexpensive spectrophotometric cell was designed for use with aqueous solutions for which temperature is a maximum of 325??C and pressure, 28 MPa. The cell has an internal volume of 5 ml and a path length of 1.31 cm. Each furnace assembly is 120 mm in diameter ?? 150 mm high and will fit into most commercial spectrophotometers. Temperature is controlled by a standard set-point controller and a balancing circuit that is used to maintain the temperature of the sample and reference cell within 1??C of each other at any temperature.

[Effect of maximum blood pressure fluctuation on prognosis of patients with acute ischemic stroke within 24 hours after hospital admission].

PubMed

Wang, H; Tang, Y; Zhang, Y; Xu, K; Zhao, J B

2018-05-10

Objective: To investigate the relationship between the maximum blood pressure fluctuation within 24 hours after admission and the prognosis at discharge. Methods: The patients with ischemic stroke admitted in Department of Neurology of the First Affiliated Hospital of Harbin Medical University within 24 hours after onset were consecutively selected from April 2016 to March 2017. The patients were grouped according to the diagnostic criteria of hypertension. Ambulatory blood pressure of the patients within 24 hours after admission were measured with bedside monitors and baseline data were collected. The patients were scored by NIHSS at discharge. The relationships between the maximum values of systolic blood pressure (SBP) or diastolic blood pressure (DBP) and the prognosis at discharge were analyzed. Results: A total of 521 patients with acute ischemic stroke were enrolled. They were divided into normal blood pressure group (82 cases) and hypertension group(439 cases). In normal blood pressure group, the maximum values of SBP and DBP were all in normal distribution ( P >0.05). The maximum value of SBP fluctuation was set at 146.6 mmHg. After adjustment for potential confounders, the OR for poor prognosis at discharge in patients with SBP fluctuation ≥146.6 mmHg was 2.669 (95 %CI : 0.594-11.992) compared with those with SBP fluctuation <146.6 mmHg. The maximum value of DBP fluctuation was set at 90.0 mmHg, and the adjusted OR for poor prognosis at discharge in patients with DBP fluctuation ≥90.0 mmHg was 0.416 (95 %CI : 0.087-1.992) compared with those with DBP fluctuation <90.0 mmHg. In hypertension group, the maximum values of SBP and DBP were not in normal distribution ( P <0.05). The maximum value of SBP fluctuation was set at median 171.0 mmHg. After adjustment for the confounders, the greater the maximum of SBP, the greater the risk of poor prognosis at discharge was, the OR was 1.636 (95 %CI : 1.014-2.641). The maximum value of DBP fluctuation was set at median 98.0 mmHg. After adjustment for the confounders, the greater the maximum of DBP, the greater the risk of poor prognosis at discharge was, the OR was 1.645 (95 %CI : 1.003-2.697). Conclusion: In acute ischemic stroke patients with normal blood pressure at admission, the maximum values of SBP and DBP within 24 hours after admission had no relationship with prognosis at discharge. In acute ischemic stroke patients with hypertension at admission, the maximum values of SBP and DBP within 24 hours after admission were associated with poor prognosis at discharge.

Tissue interface pressure and skin integrity in critically ill, mechanically ventilated patients.

PubMed

Grap, Mary Jo; Munro, Cindy L; Wetzel, Paul A; Schubert, Christine M; Pepperl, Anathea; Burk, Ruth S; Lucas, Valentina

2017-02-01

To describe tissue interface pressure, time spent above critical pressure levels and the effect on skin integrity at seven anatomical locations. Descriptive, longitudinal study in critically ill mechanically ventilated adults, from Surgical Trauma ICU-STICU; Medical Respiratory ICU-MRICU; Neuroscience ICU-NSICU in a Mid-Atlantic urban university medical centre. Subjects were enroled in the study within 24hours of intubation. Tissue interface pressure was measured continuously using the XSENSOR pressure mapping system (XSENSOR Technology Corporation, Calgary, Canada). Skin integrity was observed at all sites, twice daily, using the National Pressure Ulcer Advisory Panel staging system, for the first seven ICU days and at day 10 and 14. Of the 132 subjects, 90.9% had no observed changes in skin integrity. Maximum interface pressure was above 32mmHg virtually 100% of the time for the sacrum, left and right trochanter. At the 45mmHg level, the left and right trochanter had the greatest amount of time above this level (greater than 95% of the time), followed by the sacrum, left and right scapula, and the left and right heels. Similarly, at levels above 60mmHg, the same site order applied. For those six subjects with sacral skin integrity changes, maximum pressures were greater than 32mmHg 100% of the time. Four of the six sacral changes were associated with greater amounts of time above both 45mmHg and 60mmHg than the entire sample. Maximum tissue interface pressure was above critical levels for the majority of the documented periods, especially in the sacrum, although few changes in skin integrity were documented. Time spent above critical levels for mean pressures were considerably less compared to maximum pressures. Maximum pressures may have reflected pressure spikes, but the large amount of time above the critical pressure levels remains substantial. Copyright © 2016 Elsevier Ltd. All rights reserved.

Tissue interface pressure and skin integrity in critically ill, mechanically ventilated patients☆

PubMed Central

Grap, Mary Jo; Munro, Cindy L.; Wetzel, Paul A.; Schubert, Christine M.; Pepperl, Anathea; Burk, Ruth S.; Lucas, Valentina

2016-01-01

Summary Objective To describe tissue interface pressure, time spent above critical pressure levels and the effect on skin integrity at seven anatomical locations. Design, setting, patients Descriptive, longitudinal study in critically ill mechanically ventilated adults, from Surgical Trauma ICU-STICU; Medical Respiratory ICU-MRICU; Neuroscience ICU-NSICU in a Mid-Atlantic urban university medical centre. Subjects were enroled in the study within 24 hours of intubation. Measurements Tissue interface pressure was measured continuously using the XSENSOR pressure mapping system (XSENSOR Technology Corporation, Calgary, Canada). Skin integrity was observed at all sites, twice daily, using the National Pressure Ulcer Advisory Panel staging system, for the first seven ICU days and at day 10 and 14. Results Of the 132 subjects, 90.9% had no observed changes in skin integrity. Maximum interface pressure was above 32 mmHg virtually 100% of the time for the sacrum, left and right trochanter. At the 45 mmHg level, the left and right trochanter had the greatest amount of time above this level (greater than 95% of the time), followed by the sacrum, left and right scapula, and the left and right heels. Similarly, at levels above 60 mmHg, the same site order applied. For those six subjects with sacral skin integrity changes, maximum pressures were greater than 32 mmHg100% of the time. Four of the six sacral changes were associated with greater amounts of time above both 45 mmHg and 60 mmHg than the entire sample. Conclusions Maximum tissue interface pressure was above critical levels for the majority of the documented periods, especially in the sacrum, although few changes in skin integrity were documented. Time spent above critical levels for mean pressures were considerably less compared to maximum pressures. Maximum pressures may have reflected pressure spikes, but the large amount of time above the critical pressure levels remains substantial. PMID:27836262

49 CFR 236.701 - Application, brake; full service.

Code of Federal Regulations, 2010 CFR

2010-10-01

... a split reduction in brake pipe pressure at a service rate until maximum brake cylinder pressure is developed. As applied to an automatic or electro-pneumatic brake with speed governor control, an application other than emergency which develops the maximum brake cylinder pressure, as determined by the design of...

76 FR 1504 - Pipeline Safety: Establishing Maximum Allowable Operating Pressure or Maximum Operating Pressure...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-01-10

... profile that is dependent upon the pipelines attributes, its geographical location, design, operating... type of threats posed by the pipeline segment, including consideration of the age, design, pipe... calculation. There are several methods available for establishing MAOP or MOP. A hydrostatic pressure test...

Stress-dislocation interaction mechanism in low-temperature thermo-compression sintering of Ag NPs

NASA Astrophysics Data System (ADS)

Wang, Fuliang; Tang, Zikai; He, Hu

2018-04-01

The sintering of metal nanoparticles (NPs) has been widely studied in the field of nanotechnology, and low-temperature sintering has become the industry standard. In this study, a molecular dynamics (MD) model was established to study the sintering behaviour of silver NPs during low-temperature thermo-compression. Primarily, we studied the sintering process, in which the ratio of neck radius to particle radius (x/r) changes. Under a uniaxial pressure, the maximum ratio in the temperature range 420-425 K was 1. According to the change of x/r, the process can be broken down into three stages: the neck-formation stage, neck-growth stage, and neck-stability stage. In addition, the relationship between potential energy, internal stress, and dislocation density during sintering is discussed. The results showed that cycling internal stress played an important role in sintering. Under the uniaxial pressure, the stress-dislocation interaction was found to be the major mechanism for thermo-compression sintering because the plastic deformation product dislocation intensified the diffusion of atoms. Also, the displacement vector, the mean square displacement, and the changing crystal structure during sintering were studied.

Radiation intensification of the reactor pressure vessels recovery by low temperature heat treatment (wet annealing)

NASA Astrophysics Data System (ADS)

Krasikov, E.

2015-04-01

As a main barrier against radioactivity outlet reactor pressure vessel (RPV) is a key component in terms of NPP safety. Therefore present-day demands in RPV reliability enhance have to be met by all possible actions for RPV in-service embrittlement mitigation. Annealing treatment is known to be the effective measure to restore the RPV metal properties deteriorated by neutron irradiation. There are two approaches to annealing. The first one is so-called «dry» high temperature (∼475°C) annealing. It allows obtaining practically complete recovery, but requires the removal of the reactor core and internals. External heat source (furnace) is required to carry out RPV heat treatment. The alternative approach is to anneal RPV at a maximum coolant temperature which can be obtained using the reactor core or primary circuit pumps while operating within the RPV design limits. This low temperature «wet» annealing, although it cannot be expected to produce complete recovery, is more attractive from the practical point of view especially in cases when the removal of the internals is impossible.

LES-based characterization of a suction and oscillatory blowing fluidic actuator

NASA Astrophysics Data System (ADS)

Kim, Jeonglae; Moin, Parviz

2015-11-01

Recently, a novel fluidic actuator using steady suction and oscillatory blowing was developed for control of turbulent flows. The suction and oscillatory blowing (SaOB) actuator combines steady suction and pulsed oscillatory blowing into a single device. The actuation is based upon a self-sustained mechanism of confined jets and does not require any moving parts. The control output is determined by a pressure source and the geometric details, and no additional input is needed. While its basic mechanisms have been investigated to some extent, detailed characteristics of internal turbulent flows are not well understood. In this study, internal flows of the SaOB actuator are simulated using large-eddy simulation (LES). Flow characteristics within the actuator are described in detail for a better understanding of the physical mechanisms and improving the actuator design. LES predicts the self-sustained oscillations of the turbulent jet. Switching frequency, maximum velocity at the actuator outlets, and wall pressure distribution are in good agreement with the experimental measurements. The computational results are used to develop simplified boundary conditions for numerical experiments of active flow control. Supported by the Boeing company.

Analysis of the Explosive Internal Impact on the Barriers of Building Structures

NASA Astrophysics Data System (ADS)

Siwiński, Jarosław; Stolarski, Adam

2017-10-01

Work issues concern the safety of construction in relation to the hazards arising from explosion of the explosive charge located inside the building. The algorithms proposed in the paper for determining the parameters of the overpressure wave resulting from the detonation of clustered explosive charges, determine the basis for numerical simulation analyzes. Determination of the maximum value of peak pressure on the wave forehead of an internal explosion is presented on the basis of reflected wave analysis. Changeability in time of the internal explosion action describes the overpressure phase only. The analysis of the load caused by the internal explosive charge detonation was carried out under conditions of the undisturbed standard atmosphere. A load determination algorithm has been developed, taking into account the geometrical characteristics of the building barriers and the rooms as well as the parameters of environment in which the detonation occurs. The way of taking into account the influence of venting surfaces, i.e. windows, doors, ventilation ducts, on the overpressure wave parameters, was presented. Discloses a method to take into account the effect of the surface relief, i.e. windows, doors, air ducts, pressure wave parameters. Modification of the method for explosive overpressure determination presented by Cormie, Smith, Mays (2009), was proposed in the paper. This modification was developed on the basis of substitute impulse analysis for multiple overpressure pulses. In order to take into account the pressure distribution of explosive gases on the barrier surface, the method of modification the relationship for determination the changeability over time and space of the pressure of explosive gases, was presented. For this purpose, the changeability of the pressure wave angles of incidence to the barrier and the distance of the explosive charge to any point on the surface of the barrier, was taken into account. Based on the developed procedure, the overpressure changeability over time was determined for selected measurement points of the reference room. A comparative analysis of the determined loadings with experimental results and theoretical results of other authors, taken from the original work of Weerhiejm et al. (2012), was carried out.

Slip measurement in a frictional connection by torsional LDV

NASA Astrophysics Data System (ADS)

Schäfer, Günter; Lohrengel, Armin; Hilgermann, Jan Lukas

2016-06-01

Frictional shaft-hub connections are often used in drive train applications. The classic version is fitted by a temperature difference between the cold shaft und the hot hub, or simply axial press-fitted at room temperature. The critical point in this type of connection is the contact pressure at the edge of the hub regarding the relative deformation between the shaft and the hub under dynamic operating loads. Another innovative version, the internal press-fit, leads to a tolerance insensitive lightweight design using a tube as shaft and a controlled plastic deformation by internal high pressure. The internal press-fit connection is a special research topic at the IMW, TU Clausthal. The use of internal high pressure allows to trigger the contact pressure at the edge of the hub on an optimum value. The product of contact pressure and slipway is the key value to determine the fatigue resistance and load capacity of this kind of connection. /1/ and /2/ defined a critical range of slipway amplitudes between 5 and 25 µm for fretting. The normal use and main function of a shaft-hub connection is the transmission of torque. Regarding the different torsional stiffness of the shaft and the hub, there will be a difference in deformation in the contact zone between the shaft and the hub, which is necessary to measure on a probe under oscillating torque load. The measurement on the test-rig in /3/ was done with a POLYTEC torsional LDV (controller OFV-4000, sensor head OFV-400). In general the continuously oscillating torque load allowed a serial measurement of the torsional movement of the shaft and the hub. The difference of the two maximum values is the expected slipway between the two parts in the critical zone at the edge of the hub. The main benefits of the Torsional LDV in this application are the very small measuring point (next to the contact), no influence on the probe, no special preparation of the probe and a really good resolution. The paper gives an overview to the technical background of the measured value, to the measuring setup, to the other used measuring techniques and to the measuring results.

33 CFR Appendix A to Part 154 - Guidelines for Detonation Flame Arresters

Code of Federal Regulations, 2010 CFR

2010-07-01

... (CG-522). 1. Scope 1.1This standard provides the minimum requirements for design, construction.../Circ. 373/Rev. 1—Revised Standards for the Design, Testing and Locating of Devices to Prevent the... maximum design pressure drop for that maximum flow rate. 6.1.10Maximum operating pressure. 7. Materials 7...

Calculations of the Performance of a Compression-Ignition Engine-Compressor Turbine Combination I : Performance of a Highly Supercharged Compression-Ignition Engine

NASA Technical Reports Server (NTRS)

Sanders, J. C.; Mendelson, Alexander

1945-01-01

Small high-speed single-cylinder compression-ignition engines were tested to determine their performance characteristics under high supercharging. Calculations were made on the energy available in the exhaust gas of the compression-ignition engines. The maximum power at any given maximum cylinder pressure was obtained when the compression pressure was equal to the maximum cylinder pressure. Constant-pressure combustion was found possible at an engine speed of 2200 rpm. Exhaust pressures and temperatures were determined from an analysis of indicator cards. The analysis showed that, at rich mixtures with the exhaust back pressure equal to the inlet-air pressure, there is excess energy available for driving a turbine over that required for supercharging. The presence of this excess energy indicates that a highly supercharged compression-ignition engine might be desirable as a compressor and combustion chamber for a turbine.

Functional outcome after successful internal fixation versus salvage arthroplasty of patients with a femoral neck fracture.

PubMed

Zielinski, Stephanie M; Keijsers, Noël L; Praet, Stephan F E; Heetveld, Martin J; Bhandari, Mohit; Wilssens, Jean Pierre; Patka, Peter; Van Lieshout, Esther M M

2014-12-01

To determine patient independency, health-related and disease-specific quality of life (QOL), gait pattern, and muscle strength in patients after salvage arthroplasty for failed internal fixation of a femoral neck fracture. Secondary cohort study to a randomized controlled trial. Multicenter trial in the Netherlands, including 14 academic and nonacademic hospitals. Patients after salvage arthroplasty for failed internal fixation of a femoral neck fracture were studied. A comparison was made with patients who healed uneventfully after internal fixation. None (observatory study). Patient characteristics, SF-12, and Western Ontario McMaster osteoarthritis index scores were collected. Gait parameters were measured using plantar pressure measurement. Maximum isometric forces of the hip muscles were measured using a handheld dynamometer. Differences between the fractured and contralateral leg were calculated. Groups were compared using univariate analysis. Of 248 internal fixation patients (median age, 72 years), salvage arthroplasty was performed in 68 patients (27%). Salvage arthroplasty patients had a significantly lower Western Ontario McMaster osteoarthritis index score (median, 73 vs. 90; P = 0.016) than patients who healed uneventfully after internal fixation. Health-related QOL (SF-12) and patient independency did not differ significantly between the groups. Gait analysis showed a significantly impaired progression of the center of pressure in the salvage surgery patients (median ratio, -8.9 vs. 0.4, P = 0.013) and a significant greater loss of abduction strength (median, -25.4 vs. -20.4 N, P = 0.025). Despite a similar level of dependency and QOL, salvage arthroplasty patients have inferior functional outcome than patients who heal after internal fixation of a femoral neck fracture. Therapeutic level III.

Static test-stand performance of the YF-102 turbofan engine with several exhaust configurations for the Quiet Short-Haul Research Aircraft (QSRA)

NASA Technical Reports Server (NTRS)

Mcardle, J. G.; Homyak, L.; Moore, A. S.

1979-01-01

The performance of a YF-102 turbofan engine was measured in an outdoor test stand with a bellmouth inlet and seven exhaust-system configurations. The configurations consisted of three separate-flow systems of various fan and core nozzle sizes and four confluent-flow systems of various nozzle sizes and shapes. A computer program provided good estimates of the engine performance and of thrust at maximum rating for each exhaust configuration. The internal performance of two different-shaped core nozzles for confluent-flow configurations was determined to be satisfactory. Pressure and temperature surveys were made with a traversing probe in the exhaust-nozzle flow for some confluent-flow configurations. The survey data at the mixing plane, plus the measured flow rates, were used to calculate the static-pressure variation along the exhaust nozzle length. The computed pressures compared well with experimental wall static-pressure data. External-flow surveys were made, for some confluent-flow configurations, with a large fixed rake at various locations in the exhaust plume.

40 CFR 63.7944 - How do I determine the maximum HAP vapor pressure of my remediation material?

Code of Federal Regulations, 2014 CFR

2014-07-01

... vapor pressure of my remediation material? 63.7944 Section 63.7944 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) NATIONAL EMISSION STANDARDS FOR HAZARDOUS... Pollutants: Site Remediation Performance Tests § 63.7944 How do I determine the maximum HAP vapor pressure of...

40 CFR 63.7944 - How do I determine the maximum HAP vapor pressure of my remediation material?

Code of Federal Regulations, 2012 CFR

2012-07-01

... vapor pressure of my remediation material? 63.7944 Section 63.7944 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) NATIONAL EMISSION STANDARDS FOR HAZARDOUS... Pollutants: Site Remediation Performance Tests § 63.7944 How do I determine the maximum HAP vapor pressure of...

40 CFR 63.7944 - How do I determine the maximum HAP vapor pressure of my remediation material?

Code of Federal Regulations, 2013 CFR

2013-07-01

... vapor pressure of my remediation material? 63.7944 Section 63.7944 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) NATIONAL EMISSION STANDARDS FOR HAZARDOUS... Pollutants: Site Remediation Performance Tests § 63.7944 How do I determine the maximum HAP vapor pressure of...

40 CFR 63.7944 - How do I determine the maximum HAP vapor pressure of my remediation material?

Code of Federal Regulations, 2011 CFR

2011-07-01

... vapor pressure of my remediation material? 63.7944 Section 63.7944 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) NATIONAL EMISSION STANDARDS FOR HAZARDOUS... Pollutants: Site Remediation Performance Tests § 63.7944 How do I determine the maximum HAP vapor pressure of...

49 CFR 229.49 - Main reservoir system.

Code of Federal Regulations, 2014 CFR

2014-10-01

... least one safety valve that shall prevent an accumulation of pressure of more than 15 pounds per square... or unloads and loads the air compressor within 5 pounds per square inch above or below the maximum... pressure is not less than 15 pounds per square inch above the maximum brake pipe pressure fixed by the...

49 CFR 229.49 - Main reservoir system.

Code of Federal Regulations, 2010 CFR

2010-10-01

... least one safety valve that shall prevent an accumulation of pressure of more than 15 pounds per square... or unloads and loads the air compressor within 5 pounds per square inch above or below the maximum... pressure is not less than 15 pounds per square inch above the maximum brake pipe pressure fixed by the...

Evaluation of lung volumes, vital capacity and respiratory muscle strength after cervical, thoracic and lumbar spinal surgery.

PubMed

Oliveira, Marcio Aparecido; Vidotto, Milena Carlos; Nascimento, Oliver Augusto; Almeida, Renato; Santoro, Ilka Lopes; Sperandio, Evandro Fornias; Jardim, José Roberto; Gazzotti, Mariana Rodrigues

2015-01-01

Studies have shown that physiopathological changes to the respiratory system can occur following thoracic and abdominal surgery. Laminectomy is considered to be a peripheral surgical procedure, but it is possible that thoracic spinal surgery exerts a greater influence on lung function. The aim of this study was to evaluate the pulmonary volumes and maximum respiratory pressures of patients undergoing cervical, thoracic or lumbar spinal surgery. Prospective study in a tertiary-level university hospital. Sixty-three patients undergoing laminectomy due to diagnoses of tumors or herniated discs were evaluated. Vital capacity, tidal volume, minute ventilation and maximum respiratory pressures were evaluated preoperatively and on the first and second postoperative days. Possible associations between the respiratory variables and the duration of the operation, surgical diagnosis and smoking status were investigated. Vital capacity and maximum inspiratory pressure presented reductions on the first postoperative day (20.9% and 91.6%, respectively) for thoracic surgery (P = 0.01), and maximum expiratory pressure showed reductions on the first postoperative day in cervical surgery patients (15.3%; P = 0.004). The incidence of pulmonary complications was 3.6%. There were reductions in vital capacity and maximum respiratory pressures during the postoperative period in patients undergoing laminectomy. Surgery in the thoracic region was associated with greater reductions in vital capacity and maximum inspiratory pressure, compared with cervical and lumbar surgery. Thus, surgical manipulation of the thoracic region appears to have more influence on pulmonary function and respiratory muscle action.

Two-dimensional Cascade Investigation of the Maximum Exit Tangential Velocity Component and Other Flow Conditions at the Exit of Several Turbine Blade Designs at Supercritical Pressure Ratios

NASA Technical Reports Server (NTRS)

Hauser, Cavour H; Plohr, Henry W

1951-01-01

The nature of the flow at the exit of a row of turbine blades for the range of conditions represented by four different blade configurations was evaluated by the conservation-of-momentum principle using static-pressure surveys and by analysis of Schlieren photographs of the flow. It was found that for blades of the type investigated, the maximum exit tangential-velocity component is a function of the blade geometry only and can be accurately predicted by the method of characteristics. A maximum value of exit velocity coefficient is obtained at a pressure ratio immediately below that required for maximum blade loading followed by a sharp drop after maximum blade loading occurs.

Bubble fusion: Preliminary estimates

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

Krakowski, R.A.

1995-02-01

The collapse of a gas-filled bubble in disequilibrium (i.e., internal pressure {much_lt} external pressure) can occur with a significant focusing of energy onto the entrapped gas in the form of pressure-volume work and/or acoustical shocks; the resulting heating can be sufficient to cause ionization and the emission of atomic radiations. The suggestion that extreme conditions necessary for thermonuclear fusion to occur may be possible has been examined parametrically in terms of the ratio of initial bubble pressure relative to that required for equilibrium. In this sense, the disequilibrium bubble is viewed as a three-dimensional ``sling shot`` that is ``loaded`` tomore » an extent allowed by the maximum level of disequilibrium that can stably be achieved. Values of this disequilibrium ratio in the range 10{sup {minus}5}--10{sup {minus}6} are predicted by an idealized bubble-dynamics model as necessary to achieve conditions where nuclear fusion of deuterium-tritium might be observed. Harmonic and aharmonic pressurizations/decompressions are examined as means to achieve the required levels of disequilibrium required to create fusion conditions. A number of phenomena not included in the analysis reported herein could enhance or reduce the small levels of nuclear fusions predicted.« less

A Balanced Diaphragm Type of Maximum Cylinder Pressure Indicator

NASA Technical Reports Server (NTRS)

Spanogle, J A; Collins, John H , Jr

1930-01-01

A balanced diaphragm type of maximum cylinder pressure indicator was designed to give results consistent with engine operating conditions. The apparatus consists of a pressure element, a source of controlled high pressure and a neon lamp circuit. The pressure element, which is very compact, permits location of the diaphragm within 1/8 inch of the combustion chamber walls without water cooling. The neon lamp circuit used for indicating contact between the diaphragm and support facilitates the use of the apparatus with multicylinder engines.

Design study of an advanced gas generator. [which can be ignited during start-up period of turbine engines

NASA Technical Reports Server (NTRS)

Kim, S.; Trinh, H. P.

1993-01-01

A gas generator which can be ignited reliably during the initial start-up period and offers fairly uniform gas temperature at the exit was studied numerically. Various sizes and shapes of the mixing enhancement devices and their positions were examined to evaluate the uniformity of the exit gas temperature and the change of internal pressure drop incurred by introducing the mixing enhancement devices. By introducing a turbulence ring and a splash plate with an appropriate size and position, it was possible to obtain fairly uniform gas temperature distributions and a maximum gas temperature that is within the design limit temperature of 1600 R at the generator exit. However, with the geometry studied, the pressure drop across the generator was great, approximately 1150 psi, to satisfy the assigned design limit temperature. If the design limit temperature is increased to 1650 R, the pressure drop across the generator could be lowered by as much as 350 psi.

Component Performance Investigation of J71 Experimental Turbine I : Over-all Performance with 97-percent-design Stator Areas

NASA Technical Reports Server (NTRS)

Schum, Harold J; Davison, Elmer H

1956-01-01

The over-all component performance characteristics of a J71 experimental three-stage turbine with 97 percent design stator areas were determined over a range of speed and pressure ratio at inlet-air conditions of approximately 35 inches of mercury absolute and 700 degrees R. The turbine break internal efficiency at design operating conditions was 0.877; the maximum efficiency of 0.886 occurred at a pressure ratio of 4.0 at 120 percent of design equivalent rotor speed. In general, the turbine yielded a wide range of efficient operation, permitting flexibility in the choice of different modes of engine operation. Limiting blade loading of the third rotor was approached but not obtained over the range of conditions investigated herein. At the design operating point, the turbine equivalent weight flow was approximately 105 percent of design. Choking of the third-rotor blades occurred at design speed and an over-all pressure ratio of 4.2.

Neural-Net Processed Characteristic Patterns for Measurement of Structural Integrity of Pressure Cycled Components

NASA Technical Reports Server (NTRS)

Decker, A. J.

2001-01-01

A neural-net inspection process has been combined with a bootstrap training procedure and electronic holography to detect changes or damage in a pressure-cycled International Space Station cold plate to be used for cooling instrumentation. The cold plate was excited to vibrate in a normal mode at low amplitude, and the neural net was trained by example to flag small changes in the mode shape. The NDE (nondestructive-evaluation) technique is straightforward but in its infancy; its applications are ad-hoc and uncalibrated. Nevertheless previous research has shown that the neural net can detect displacement changes to better than 1/100 the maximum displacement amplitude. Development efforts that support the NDE technique are mentioned briefly, followed by descriptions of electronic holography and neural-net processing. The bootstrap training procedure and its application to detection of damage in a pressure-cycled cold plate are discussed. Suggestions for calibrating and quantifying the NDE procedure are presented.

The comparative analysis of the current-meter method and the pressure-time method used for discharge measurements in the Kaplan turbine penstocks

NASA Astrophysics Data System (ADS)

Adamkowski, A.; Krzemianowski, Z.

2012-11-01

The paper presents experiences gathered during many years of utilizing the current-meter and pressure-time methods for flow rate measurements in many hydropower plants. The integration techniques used in these both methods are different from the recommendations contained in the relevant international standards, mainly from the graphical and arithmetical ones. The results of the comparative analysis of both methods applied at the same time during the hydraulic performance tests of two Kaplan turbines in one of the Polish hydropower plant are presented in the final part of the paper. In the case of the pressure-time method application, the concrete penstocks of the tested turbines required installing a special measuring instrumentation inside the penstock. The comparison has shown a satisfactory agreement between the results of discharge measurements executed using the both considered methods. Maximum differences between the discharge values have not exceeded 1.0 % and the average differences have not been greater than 0.5 %.

Optimum performance of explosives in a quasistatic detonation cycle

NASA Astrophysics Data System (ADS)

Baker, Ernest L.; Stiel, Leonard I.

2017-01-01

Analyses were conducted on the behavior of explosives in a quasistatic detonation cycle. This type of cycle has been proposed for the determination of the maximum work that can be performed by the explosive. The Jaguar thermochemical equilibrium program enabled the direct analyses of explosive performance at the various steps in the detonation cycle. In all cases the explosive is initially detonated to a point on the Hugoniot curve for the reaction products. The maximum useful work that can be obtained from the explosive is equal to the P-V work on the isentrope for expansion after detonation to atmospheric pressure, minus one-half the square of the particle velocity at the detonation point. This quantity is calculated form the internal energy of the explosive at the initial and final atmospheric temperatures. Cycle efficiencies (net work/ heat added) are also calculated with these procedures. For several explosives including TNT, RDX, and aluminized compositions, maximum work effects were established through the Jaguar calculations for Hugoniot points corresponding to C-J, overdriven, underdriven and constant volume detonations. Detonation to the C-J point is found to result in the maximum net work in all cases.

Development and validity of a new model for assessing pressure redistribution properties of support surfaces.

PubMed

Matsuo, Junko; Sugama, Junko; Sanada, Hiromi; Okuwa, Mayumi; Nakatani, Toshio; Konya, Chizuko; Sakamoto, Jirou

2011-05-01

Pressure ulcers are a common problem, especially in older patients. In Japan, most institutionalized older people are malnourished and show extreme bony prominence (EBP). EBP is a significant factor in the development of pressure ulcers due to increased interface pressure concentrated at the skin surface over the EBP. The use of support surfaces is recommended for the prophylaxis of pressure ulcers. However, the present equivocal criteria for evaluating the pressure redistribution of support surfaces are inadequate. Since pressure redistribution is influenced by physique and posture, evaluations using human subjects are limited. For this reason, models that can substitute for humans are necessary. We developed a new EBP model based on the anthropometric measurements, including pelvic inclination, of 100 bedridden elderly people. A comparison between the pressure distribution charts of our model and bedridden elderly subjects demonstrated that maximum contact pressure values, buttock contact pressure values, and bone prominence rates corresponded closely. This indicates that the model provides a good approximation of the features of elderly people with EBP. We subsequently examined the validity of the model through quantitative assessment of pressure redistribution functions consisting of immersion, envelopment, and contact area change. The model was able to detect differences in the hardness of urethane foam, differences in the internal pressure of an air mattress, and sequential changes during the pressure switching mode. These results demonstrate the validity of our new buttock model in evaluating pressure redistribution for a variety of surfaces. Copyright © 2010 Tissue Viability Society. Published by Elsevier Ltd. All rights reserved.

Test Plan for the Boiling Water Reactor Dry Cask Simulator

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

Durbin, Samuel; Lindgren, Eric R.

The thermal performance of commercial nuclear spent fuel dry storage casks are evaluated through detailed numerical analysis . These modeling efforts are completed by the vendor to demonstrate performance and regulatory compliance. The calculations are then independently verified by the Nuclear Regulatory Commission (NRC). Carefully measured data sets generated from testing of full sized casks or smaller cask analogs are widely recognized as vital for validating these models. Recent advances in dry storage cask designs have significantly increased the maximum thermal load allowed in a cask in part by increasing the efficiency of internal conduction pathways and by increasing themore » internal convection through greater canister helium pressure. These same vertical, canistered cask systems rely on ventilation between the canister and the overpack to convect heat away from the canister to the environment for both above and below-ground configurations. While several testing programs have been previously conducted, these earlier validation attempts did not capture the effects of elevated helium pressures or accurately portray the external convection of above-ground and below-ground canistered dry cask systems. The purpose of the investigation described in this report is to produce a data set that can be used to test the validity of the assumptions associated with the calculations presently used to determine steady-state cladding temperatures in modern vertical, canistered dry cask systems. The BWR cask simulator (BCS) has been designed in detail for both the above-ground and below-ground venting configurations. The pressure vessel representing the canister has been designed, fabricated, and pressure tested for a maximum allowable pressure (MAWP) rating of 24 bar at 400 deg C. An existing electrically heated but otherwise prototypic BWR Incoloy-clad test assembly is being deployed inside of a representative storage basket and cylindrical pressure vessel that represents the canister. The symmetric single assembly geometry with well-controlled boundary conditions simplifies interpretation of results. Various configurations of outer concentric ducting will be used to mimic conditions for above and below-ground storage configurations of vertical, dry cask systems with canisters. Radial and axial temperature profiles will be measured for a wide range of decay power and helium cask pressures. Of particular interest is the evaluation of the effect of increased helium pressure on allowable heat load and the effect of simulated wind on a simplified below ground vent configuration. While incorporating the best available information, this test plan is subject to changes due to improved understanding from modeling or from as-built deviations to designs. As-built conditions and actual procedures will be documented in the final test report.« less

Design and Testing of a Variable Pressure Regulator for the Constellation Space Suit

NASA Technical Reports Server (NTRS)

Gill, Larry; Campbell, Colin

2008-01-01

The next generation space suit requires additional capabilities for controlling and adjusting internal pressure than previous design suits. Next generation suit pressures will range from slight pressure, for astronaut prebreath comfort, to hyperbaric pressure levels for emergency medical treatment. Carleton was awarded a contract in 2008 to design and build a proof of concept bench top demonstrator regulator having five setpoints which are selectable using input electronic signaling. Although the basic regulator architecture is very similar to the existing SOP regulator used in the current EMU, the major difference is the electrical selectivity of multiple setpoints rather than the mechanical On/Off feature found on the SOP regulator. The concept regulator employs a linear actuator stepper motor combination to provide variable compression to a custom design main regulator spring. This concept allows for a continuously adjustable outlet pressures from 8.2 psid (maximum) down to "firm" zero thus effectively allowing it to serve as a shutoff valve. This paper details the regulator design and presents test results on regulation band width, command set point accuracy; slue rate and regulation stability, particularly when the set point is being slued. Projections for a flight configuration version are also offered for performance, architectural layout and weight.

Comparison of devices for newborn ventilation in the delivery room.

PubMed

Szyld, Edgardo; Aguilar, Adriana; Musante, Gabriel A; Vain, Nestor; Prudent, Luis; Fabres, Jorge; Carlo, Waldemar A

2014-08-01

To evaluate the effectiveness and safety of a T-piece resuscitator compared with a self-inflating bag for providing mask ventilation to newborns at birth. Newborns at ≥26 weeks gestational age receiving positive-pressure ventilation at birth were included in this multicenter cluster-randomized 2-period crossover trial. Positive-pressure ventilation was provided with either a self-inflating bag (self-inflating bag group) with or without a positive end-expiratory pressure valve or a T-piece with a positive end-expiratory pressure valve (T-piece group). Delivery room management followed American Academy of Pediatrics and International Liaison Committee on Resuscitation guidelines. The primary outcome was the proportion of newborns with heart rate (HR)≥100 bpm at 2 minutes after birth. A total of 1027 newborns were included. There was no statistically significant difference in the incidence of HR≥100 bpm at 2 minutes after birth between the T-piece and self-inflating bag groups: 94% (479 of 511) and 90% (466 of 516), respectively (OR, 0.65; 95% CI, 0.41-1.05; P=.08). A total of 86 newborns (17%) in the T-piece group and 134 newborns (26%) in the self-inflating bag group were intubated in the delivery room (OR, 0.58; 95% CI, 0.4-0.8; P=.002). The mean±SD maximum positive inspiratory pressure was 26±2 cm H2O in the T-piece group vs 28±5 cm H2O in the self-inflating bag group (P<.001). Air leaks, use of drugs/chest compressions, mortality, and days on mechanical ventilation did not differ significantly between groups. There was no difference between the T-piece resuscitator and a self-inflating bag in achieving an HR of ≥100 bpm at 2 minutes in newborns≥26 weeks gestational age resuscitated at birth. However, use of the T-piece decreased the intubation rate and the maximum pressures applied. Copyright © 2014 Elsevier Inc. All rights reserved.

Development of a gas-pressurized high-pressure μSR setup at the RIKEN-RAL Muon Facility

NASA Astrophysics Data System (ADS)

Watanabe, I.; Ishii, Y.; Kawamata, T.; Suzuki, T.; Pratt, F. L.; Done, R.; Chowdhury, M.; Goodway, C.; Dreyer, J.; Smith, C.; Southern, M.

2009-04-01

The development and testing of a gas-pressurized μSR setup for the RIKEN-RAL Muon Facility is reported. In collaboration with the high-pressure group of the ISIS Facility at the Rutherford Appleton Laboratory, a gas-pressurized setup for a pulsed muon beam at the RIKEN-RAL Muon Facility has been constructed in 2008. The sample is pressurized by helium gas and the designed maximum pressure is 6.4 kbar. The high-pressure cell can be cooled down to 2 K using an existing cryostat. Tests were made injecting the double-pulsed muon beam into a high-purity sample of Sn powder, which confirmed that the maximum pressure achieved at 2 K was close to the designed pressure.

3D finite element analysis of changes in stress levels and distributions for an osseointegrated implant after vertical bone loss.

PubMed

Yoon, Kyung-Ho; Kim, Su-Gwan; Lee, Jeong-Hoon; Suh, Seung-Woo

2011-10-01

The effect of stress levels and distributions around the internal nonsubmerged type implants after vertical bone resorption was investigated in this study. An HSII implant was placed in 4 cylindrical alveolar bone models with differing degrees of thread exposures. The load applied to each implant was von Mises stress and principal stress, 250 N in axial direction and 30 degrees lateral pressure. The difference in the load between the bone and the connective portion of the implant was obtained using ANSYS analysis. Bone loss in the cervical area of the implant was more obvious under lateral pressure. When more threads were exposed, bone level decreased and the maximum load applied on the fixture increased. It was concluded that higher bone level has a biomechanical advantage with respect to stress concentration.

Endotracheal Tube Cuff Pressures in Patients Intubated Prior to Helicopter EMS Transport.

PubMed

Tennyson, Joseph; Ford-Webb, Tucker; Weisberg, Stacy; LeBlanc, Donald

2016-11-01

Endotracheal intubation is a common intervention in critical care patients undergoing helicopter emergency medical services (HEMS) transportation. Measurement of endotracheal tube (ETT) cuff pressures is not common practice in patients referred to our service. Animal studies have demonstrated an association between the pressure of the ETT cuff on the tracheal mucosa and decreased blood flow leading to mucosal ischemia and scarring. Cuff pressures greater than 30 cmH 2 O impede mucosal capillary blood flow. Multiple prior studies have recommended 30 cmH 2 O as the maximum safe cuff inflation pressure. This study sought to evaluate the inflation pressures in ETT cuffs of patients presenting to HEMS. We enrolled a convenience sample of patients presenting to UMass Memorial LifeFlight who were intubated by the sending facility or emergency medical services (EMS) agency. Flight crews measured the ETT cuff pressures using a commercially available device. Those patients intubated by the flight crew were excluded from this analysis as the cuff was inflated with the manometer to a standardized pressure. Crews logged the results on a research form, and we analyzed the data using Microsoft Excel and an online statistical analysis tool. We analyzed data for 55 patients. There was a mean age of 57 years (range 18-90). The mean ETT cuff pressure was 70 (95% CI= [61-80]) cmH 2 O. The mean lies 40 cmH 2 O above the maximum accepted value of 30 cmH 2 O (p<0.0001). Eighty-four percent (84%) of patients encountered had pressures above the recommended maximum. The most frequently recorded pressure was >120 cmH 2 O, the maximum pressure on the analog gauge. Patients presenting to HEMS after intubation by the referral agency (EMS or hospital) have ETT cuffs inflated to pressures that are, on average, more than double the recommended maximum. These patients are at risk for tracheal mucosal injury and scarring from decreased mucosal capillary blood flow. Hospital and EMS providers should use ETT cuff manometry to ensure that they inflate ETT cuffs to safe pressures.

Endotracheal Tube Cuff Pressures in Patients Intubated Prior to Helicopter EMS Transport

PubMed Central

Tennyson, Joseph; Ford-Webb, Tucker; Weisberg, Stacy; LeBlanc, Donald

2016-01-01

Introduction Endotracheal intubation is a common intervention in critical care patients undergoing helicopter emergency medical services (HEMS) transportation. Measurement of endotracheal tube (ETT) cuff pressures is not common practice in patients referred to our service. Animal studies have demonstrated an association between the pressure of the ETT cuff on the tracheal mucosa and decreased blood flow leading to mucosal ischemia and scarring. Cuff pressures greater than 30 cmH2O impede mucosal capillary blood flow. Multiple prior studies have recommended 30 cmH2O as the maximum safe cuff inflation pressure. This study sought to evaluate the inflation pressures in ETT cuffs of patients presenting to HEMS. Methods We enrolled a convenience sample of patients presenting to UMass Memorial LifeFlight who were intubated by the sending facility or emergency medical services (EMS) agency. Flight crews measured the ETT cuff pressures using a commercially available device. Those patients intubated by the flight crew were excluded from this analysis as the cuff was inflated with the manometer to a standardized pressure. Crews logged the results on a research form, and we analyzed the data using Microsoft Excel and an online statistical analysis tool. Results We analyzed data for 55 patients. There was a mean age of 57 years (range 18–90). The mean ETT cuff pressure was 70 (95% CI= [61–80]) cmH2O. The mean lies 40 cmH2O above the maximum accepted value of 30 cmH2O (p<0.0001). Eighty-four percent (84%) of patients encountered had pressures above the recommended maximum. The most frequently recorded pressure was >120 cmH2O, the maximum pressure on the analog gauge. Conclusion Patients presenting to HEMS after intubation by the referral agency (EMS or hospital) have ETT cuffs inflated to pressures that are, on average, more than double the recommended maximum. These patients are at risk for tracheal mucosal injury and scarring from decreased mucosal capillary blood flow. Hospital and EMS providers should use ETT cuff manometry to ensure that they inflate ETT cuffs to safe pressures. PMID:27833679

Biomechanical analysis of articular-sided partial-thickness rotator cuff tear and repair.

PubMed

Mihata, Teruhisa; McGarry, Michelle H; Ishihara, Yoko; Bui, Christopher N H; Alavekios, Damon; Neo, Masashi; Lee, Thay Q

2015-02-01

Articular-sided partial-thickness rotator cuff tears are common injuries in throwing athletes. The superior shoulder capsule beneath the supraspinatus and infraspinatus tendons works as a stabilizer of the glenohumeral joint. To assess the effect of articular-sided partial-thickness rotator cuff tear and repair on shoulder biomechanics. The hypothesis was that shoulder laxity might be changed because of superior capsular plication in transtendon repair of articular-sided partial-thickness rotator cuff tears. Controlled laboratory study. Nine fresh-frozen cadaveric shoulders were tested by using a custom shoulder-testing system at the simulated late-cocking phase and acceleration phase of throwing motion. Maximum glenohumeral external rotation angle, anterior translation, position of the humeral head apex with respect to the glenoid, internal impingement area, and glenohumeral and subacromial contact pressures were measured. Each specimen underwent 3 stages of testing: stage 1, with the intact shoulder; stage 2, after creation of articular-sided partial-thickness tears of the supraspinatus and infraspinatus tendons; and stage 3, after transtendon repair of the torn tendons by using 2 suture anchors. Articular-sided partial-thickness tears did not significantly change any of the shoulder biomechanical measurements. In the simulated late-cocking phase, transtendon rotator cuff repair resulted in decreased maximum external rotation angle by 4.2° (P = .03), posterior shift of the humeral head (1.1-mm shift; P = .02), decreased glenohumeral contact pressure by 1.7 MPa (56%; P = .004), and decreased internal impingement area by 26.4 mm(2) (65%; P < .001) compared with values in the torn shoulder. In the acceleration phase, the humeral head shifted inferiorly (1.2-mm shift; P = .03 vs torn shoulder), and glenohumeral anterior translation (1.5-mm decrease; P = .03 vs torn shoulder) and subacromial contact pressure (32% decrease; P = .004 vs intact shoulder) decreased significantly after transtendon repair. Transtendon repair of articular-sided partial-thickness supraspinatus and infraspinatus tears decreased glenohumeral and subacromial contact pressures at time zero; these changes might lead to reduced secondary subacromial and internal impingements and consequently progression to full-thickness rotator cuff tear. However, repair of the tendons decreased anterior translation and external rotation and changed the positional relationship between the humeral head and the glenoid. Careful attention should be paid to shoulder laxity and range of motion when transtendon repair is chosen to treat articular-sided partial-thickness rotator cuff tears, specifically in throwing athletes. © 2014 The Author(s).

The shouted voice: A pilot study of laryngeal physiology under extreme aerodynamic pressure.

PubMed

Lagier, Aude; Legou, Thierry; Galant, Camille; Amy de La Bretèque, Benoit; Meynadier, Yohann; Giovanni, Antoine

2017-12-01

The objective was to study the behavior of the larynx during shouted voice production, when the larynx is exposed to extremely high subglottic pressure. The study involved electroglottographic, acoustic, and aerodynamic analyses of shouts produced at maximum effort by three male participants. Under a normal speaking voice, the voice sound pressure level (SPL) is proportional to the subglottic pressure. However, when the subglottic pressure reached high levels, the voice SPL reached a maximum value and then decreased as subglottic pressure increased further. Furthermore, the electroglottographic signal sometimes lost its periodicity during the shout, suggesting irregular vocal fold vibration.

Magnetization at high pressure in CeP

NASA Astrophysics Data System (ADS)

Naka, T.; Matsumoto, T.; Okayama, Y.; Môri, N.; Haga, Y.; Suzuki, T.

1995-02-01

We have investigated the pressure dependence of magnetization below 60 K up to 1.6 GPa in the low-carrier concentration system CeP showing two step transitions at T = TL and TH under high pressure. At high pressure, M( P, T) exhibits a maximum at around the lower transition temperature TL. This behavior implies that the magnetic state changes at TL. The pressure dependence of isothermal magnetization M( P) is different above and below TL. In fact, M( P) below TL exhibits a maximum at around 1.4 GPa, whereas M( P) above TL increases steeply with pressure up to 1.6 GPa.

A solar cycle dependence of nonlinearity in magnetospheric activity

NASA Astrophysics Data System (ADS)

Johnson, Jay R.; Wing, Simon

2005-04-01

The nonlinear dependencies inherent to the historical Kp data stream (1932-2003) are examined using mutual information and cumulant-based cost as discriminating statistics. The discriminating statistics are compared with surrogate data streams that are constructed using the corrected amplitude adjustment Fourier transform (CAAFT) method and capture the linear properties of the original Kp data. Differences are regularly seen in the discriminating statistics a few years prior to solar minima, while no differences are apparent at the time of solar maxima. These results suggest that the dynamics of the magnetosphere tend to be more linear at solar maximum than at solar minimum. The strong nonlinear dependencies tend to peak on a timescale around 40-50 hours and are statistically significant up to 1 week. Because the solar wind driver variables, VBs, and dynamical pressure exhibit a much shorter decorrelation time for nonlinearities, the results seem to indicate that the nonlinearity is related to internal magnetospheric dynamics. Moreover, the timescales for the nonlinearity seem to be on the same order as that for storm/ring current relaxation. We suggest that the strong solar wind driving that occurs around solar maximum dominates the magnetospheric dynamics, suppressing the internal magnetospheric nonlinearity. On the other hand, in the descending phase of the solar cycle just prior to solar minimum, when magnetospheric activity is weaker, the dynamics exhibit a significant nonlinear internal magnetospheric response that may be related to increased solar wind speed.

Influence of nitromethane concentration on ignition energy and explosion parameters in gaseous nitromethane/air mixtures.

PubMed

Zhang, Qi; Li, Wei; Lin, Da-Chao; He, Ning; Duan, Yun

2011-01-30

The aim of this paper is to provide new experimental data of the minimum ignition energy (MIE) of gaseous nitromethane/air mixtures to discuss the explosion pressure and the flame temperature as a function of nitromethane concentration. Observations on the influence of nitromethane concentration on combustion pressure and temperature through the pressure and temperature measure system show that peak temperature (the peak of combustion temperature wave) is always behind peak pressure (the peak of the combustion pressure wave) in arrival time, the peak combustion pressure of nitromethane increases in the range of its volume fraction 10-40% as the concentration of nitromethane increases, and it slightly decreases in the range of 40-50%. The maximum peak pressure is equal to 0.94 MPa and the minimum peak pressure 0.58 MPa. Somewhat similar to the peak pressure, the peak combustion temperature increases with the volume fraction of nitromethane in the range of 10-40%, and slightly decreases in 40-50%. The maximum peak temperature is 1340 °C and the minimum 860 °C. The combustion temperature rise rate increases with the concentration of nitromethane in 10-30%, while decreases in 30-50% and its maximum value of combustion temperature rise rate in 10-50% is 4200 °C/s at the volume fraction of 30%. Influence of the concentration of nitromethane on the combustion pressure rise rate is relatively complicated, and the maximum value of rise rate of combustion pressure wave in 10-50% is 11 MPa/s at the concentration 20%. Copyright © 2010 Elsevier B.V. All rights reserved.

Fuselage ventilation due to wind flow about a postcrash aircraft

NASA Technical Reports Server (NTRS)

Stuart, J. W.

1980-01-01

Postcrash aircraft fuselage fire development, dependent on the internal and external fluid dynamics is discussed. The natural ventilation rate, a major factor in the internal flow patterns and fire development is reviewed. The flow about the fuselage as affected by the wind and external fire is studied. An analysis was performend which estimated the rates of ventilation produced by the wind for a limited idealized environmental configuration. The simulation utilizes the empirical pressure coefficient distribution of an infinite circular cylinder near a wall with its boundary later flow to represent the atmospheric boundary layer. The resulting maximum ventilation rate for two door size openings, with varying circumferential location in a common 10 mph wind was an order of magnitude greater than the forced ventilation specified in full scale fire testing. The parameter discussed are: (1) fuselage size and shape, (2) fuselage orientation and proximity to the ground, (3) fuselage-openings size and location, (4) wind speed and direction, and (5) induced flow of the external fire plume is recommended. The fire testing should be conducted to a maximum ventilation rate at least an order of magnitude greater than the inflight air conditioning rates.

Studies on droplet evaporation and combustion in high pressures

NASA Technical Reports Server (NTRS)

Sato, J.

1993-01-01

High pressure droplet evaporation and combustion have been studied up to 15 MPa under normal and microgravity fields. From the evaporation studies, it has been found that in the supercritical environments, the droplet evaporation rate and lifetime take a maximum and a minimum at an ambient pressure over the critical pressure. Its maximum and minimum points move toward the lower ambient pressures if the ambient temperature is increased. It has been found from the combustion studies that the burning life time takes a minimum at an ambient pressure being equal to the critical pressure. It is attributable to both the pressure dependency of the diffusion rate and the droplet evaporation characteristics described above.

Design of a Collapse-Mode CMUT With an Embossed Membrane for Improving Output Pressure.

PubMed

Yu, Yuanyu; Pun, Sio Hang; Mak, Peng Un; Cheng, Ching-Hsiang; Wang, Jiujiang; Mak, Pui-In; Vai, Mang I

2016-06-01

Capacitive micromachined ultrasonic transducers (CMUTs) have emerged as a competitive alternative to piezoelectric ultrasonic transducers, especially in medical ultrasound imaging and therapeutic ultrasound applications, which require high output pressure. However, as compared with piezoelectric ultrasonic transducers, the output pressure capability of CMUTs remains to be improved. In this paper, a novel structure is proposed by forming an embossed vibrating membrane on a CMUT cell operating in the collapse mode to increase the maximum output pressure. By using a beam model in undamped conditions and finite-element analysis simulations, the proposed embossed structure showed improvement on the maximum output pressure of the CMUT cell when the embossed pattern was placed on the estimated location of the peak deflection. As compared with a uniform membrane CMUT cell worked in the collapse mode, the proposed CMUT cell can yield the maximum output pressure by 51.1% and 88.1% enhancement with a single embossed pattern made of Si3N4 and nickel, respectively. The maximum output pressures were improved by 34.9% (a single Si3N4 embossed pattern) and 46.7% (a single nickel embossed pattern) with the uniform membrane when the center frequencies of both original and embossed CMUT designs were similar.

Characteristics of the internal and external sources of the Mediterranean synoptic cyclones for the period 1956-2013

NASA Astrophysics Data System (ADS)

Almazroui, Mansour; Awad, Adel M.; Nazrul Islam, M.

2017-07-01

This paper investigates the main sources and features of the Mediterranean synoptic cyclones affecting the basin, using the cyclone tracks. The cyclones' tracks are identified using sea level pressure (SLP) from the NCEP/NCAR reanalysis data for the period 1956-2013. The identified cyclones are classified into two categories: basin affected and basin non-affected. Most of the basin-affected (non-affected) cyclones are internal (external), i.e., generated inside (outside) the Mediterranean basin. This study reveals four (five) main sources of internal (external) cyclones. These four (five) main sources generated about 63.76% (57.25%) of the internal (external) cyclones. Seasonal analysis shows that most of the basin-affected internal (external) cyclones were generated in the winter (spring) season. The lowest number of cyclones were found in the summer. Moreover, the synoptic study of the atmospheric systems accompanied the highest- and lowest-generated years demonstrates that the deepening of the north Europe cyclones and the relative positions of Azores- and Siberian-high systems represent the important factors that influence the number of internal cyclones. Essential factors influencing the external cyclones are the strength of the maximum upper wind, Azores high, Siberian high, and orientations of their ridges.

Trial of validation of two devices for self-measurement of blood pressure according to the European Society of Hypertension International Protocol: the Citizen CH-432B and the Citizen CH-656C.

PubMed

Cotte, Uwe V; Faltenbacher, Verena H; von Willich, Werner; Bogner, Johannes R

2008-02-01

Two devices for self-measurement of blood pressure, one at the upper arm (Citizen CH-432B) and one at the wrist (Citizen CH-656C), were evaluated according to the International Protocol of the European Society of Hypertension. The International Protocol is divided into two phases: the first phase is performed on 15 selected participants with five participants in three different blood pressure ranges. If the devices passed this phase, 18 additional participants selected on the basis of the same criteria as in phase 1 were included. Two skilled observers performed the following blood pressure measurements: five measurements were performed with the mercury standard alternating with four measurements with each of the test devices per participant. The first measurement result from each device instrument was not included in the analysis. The difference between the blood pressure value given by the devices and that obtained by the two observers (mean of the two observers) was calculated for each pair of measurements and classified into three categories (within 5, 10 and 15 mmHg). The results were compared to the pass criteria established by the European Society of Hypertension. Afterwards the number of measurement differences falling within 5 mmHg was determined for every person. At least 22 of the 33 participants should have two of their three comparisons within 5 mmHg and there should be a maximum of three participants without a measurement difference within the 5 mmHg range. Both tested devices passed the first phase of the validation process by exceeding the required number of comparisons falling within the 5, 10 and 15 mmHg error zones. Even the second phase confirmed the validation criteria with average differences between the device and the mercury sphygmomanometer of 0.7+/-4.4 and -3.6+/-4.0 mmHg for systolic blood pressure and diastolic blood pressure, respectively, for the Citizen CH-432B device and -0.7+/-6.0 and -1.2+/-4.5 mmHg for the Citizen CH-656C device. Phase 2 contains furthermore an individual analysis of the 33 participants, the requirements of which were also fulfilled by both devices. The Citizen CH-432B and the Citizen CH-656C devices pass the validation recommendations of the International Protocol. They can be recommended for clinical use.

Small, high-pressure liquid hydrogen turbopump

NASA Technical Reports Server (NTRS)

Csomor, A.; Sutton, R.

1977-01-01

A high pressure, liquid hydrogen turbopump was designed, fabricated, and tested to a maximum speed of 9739 rad/s and a maximum pump discharge pressure of 2861 N/sq. cm. The approaches used in the analysis and design of the turbopump are described, and fabrication methods are discussed. Data obtained from gas generator tests, turbine performance calibration, and turbopump testing are presented.

Strong environmental tolerance of moss Venturiella under very high pressure

NASA Astrophysics Data System (ADS)

Ono, F.; Mori, Y.; Takarabe, K.; Nishihira, N.; Shindo, A.; Saigusa, M.; Matsushima, Y.; Saini, N. L.; Yamashita, M.

2010-03-01

It was shown by the present authors group that tardigrade can survive under high pressure of 7.5 GPa. In the case of land plants, however, no result of such experiment has been reported. We have extended our experiments to moss searching for lives under very high pressure. Spore placentas of moss Venturiella were sealed in a small Teflon capsule together with a liquid pressure medium. The capsule was put in the center of a pyrophillite cube, and the maximum pressure of 7.5 GPa was applied using a two-stage cubic anvil press. The pressure was kept constant at the maximum pressure for12, 24, 72 and 144 hours. After the pressure was released, the spores were seeded on a ager medium, and incubated for one week and more longer at 25°C with white light of 2000 lux. It was proved that 70-90% of the spores were alive and germinated after exposed to the maximum pressure of 7.5 GPa for up to 72 hours. However, after exposed to 7.5 GPa for 6 days, only 4 individuals in a hundred were germinated. The pressure tolerance of moss Venturiella is found to be stronger than a small animal, tardigrade.

Water-Pressure Distribution on Seaplane Float

NASA Technical Reports Server (NTRS)

Thompson, F L

1929-01-01

The investigation presented in this report was conducted for the purpose of determining the distribution and magnitude of water pressures likely to be experienced on seaplane hulls in service. It consisted of the development and construction of apparatus for recording water pressures lasting one one-hundredth second or longer and of flight tests to determine the water pressures on a UO-1 seaplane float under various conditions of taxiing, taking off, and landing. The apparatus developed was found to operate with satisfactory accuracy and is suitable for flight tests on other seaplanes. The tests on the UO-1 showed that maximum pressures of about 6.5 pounds per square inch occur at the step for the full width of the float bottom. Proceeding forward from the step the maximum pressures decrease in magnitude uniformly toward the bow, and the region of highest pressures narrows toward the keel. Immediately abaft the step the maximum pressures are very small, but increase in magnitude toward the stern and there once reached a value of about 5 pounds per square inch. (author)

Numerical Modeling of Fluid Flow in Solid Tumors

PubMed Central

Soltani, M.; Chen, P.

2011-01-01

A mathematical model of interstitial fluid flow is developed, based on the application of the governing equations for fluid flow, i.e., the conservation laws for mass and momentum, to physiological systems containing solid tumors. The discretized form of the governing equations, with appropriate boundary conditions, is developed for a predefined tumor geometry. The interstitial fluid pressure and velocity are calculated using a numerical method, element based finite volume. Simulations of interstitial fluid transport in a homogeneous solid tumor demonstrate that, in a uniformly perfused tumor, i.e., one with no necrotic region, because of the interstitial pressure distribution, the distribution of drug particles is non-uniform. Pressure distribution for different values of necrotic radii is examined and two new parameters, the critical tumor radius and critical necrotic radius, are defined. Simulation results show that: 1) tumor radii have a critical size. Below this size, the maximum interstitial fluid pressure is less than what is generally considered to be effective pressure (a parameter determined by vascular pressure, plasma osmotic pressure, and interstitial osmotic pressure). Above this size, the maximum interstitial fluid pressure is equal to effective pressure. As a consequence, drugs transport to the center of smaller tumors is much easier than transport to the center of a tumor whose radius is greater than the critical tumor radius; 2) there is a critical necrotic radius, below which the interstitial fluid pressure at the tumor center is at its maximum value. If the tumor radius is greater than the critical tumor radius, this maximum pressure is equal to effective pressure. Above this critical necrotic radius, the interstitial fluid pressure at the tumor center is below effective pressure. In specific ranges of these critical sizes, drug amount and therefore therapeutic effects are higher because the opposing force, interstitial fluid pressure, is low in these ranges. PMID:21673952

Effects of EVA gloves on grip strength and fatigue under low temperature and low pressure.

PubMed

Tian, Yinsheng; Ding, Li; Liu, Heqing; Li, Yan; Li, Deyu; Wang, Li

2016-03-01

To study the effects of wearing extravehicular activity (EVA) gloves on grip strength and fatigue in low temperature, low pressure and mixing of two factors (low temperature and low pressure). The maximum grip strength and fatigue tests were performed with 10 healthy male subjects wearing gloves in a variety of simulated environments. The data was analysed using the normalization method. The results showed that wearing gloves significantly affected the maximum grip strength and fatigue. Pressure (29.6, 39.2 kPa) had more influence on the maximum grip compared with control group while low temperatures (-50, -90, -110 °C) had no influence on grip but affected fatigue dramatically. The results also showed that the maximum grip strength and fatigue were influenced significantly in a compound environment. Space environment remarkably reduced strength and endurance of the astronauts. However, the effects brought by the compound environment cannot be understood as the superimposition of low temperature and pressure effects. Copyright © 2015 Elsevier Ltd and The Ergonomics Society. All rights reserved.

49 CFR 195.106 - Internal design pressure.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 49 Transportation 3 2011-10-01 2011-10-01 false Internal design pressure. 195.106 Section 195.106... PIPELINE Design Requirements § 195.106 Internal design pressure. (a) Internal design pressure for the pipe in a pipeline is determined in accordance with the following formula: P=(2St/D)×E×F P=Internal design...

49 CFR 195.106 - Internal design pressure.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 49 Transportation 3 2010-10-01 2010-10-01 false Internal design pressure. 195.106 Section 195.106... PIPELINE Design Requirements § 195.106 Internal design pressure. (a) Internal design pressure for the pipe in a pipeline is determined in accordance with the following formula: P=(2St/D)×E×F P=Internal design...

Biomechanical effect of latissimus dorsi tendon transfer for irreparable massive cuff tear.

PubMed

Oh, Joo Han; Tilan, Justin; Chen, Yu-Jen; Chung, Kyung Chil; McGarry, Michelle H; Lee, Thay Q

2013-02-01

The purpose of this study was to determine the biomechanical effects of latissimus dorsi transfer in a cadaveric model of massive posterosuperior rotator cuff tear. Eight cadaveric shoulders were tested at 0°, 30°, and 60° of abduction in the scapular plane with anatomically based muscle loading. Humeral rotational range of motion and the amount of humeral rotation due to muscle loading were measured. Glenohumeral kinematics and contact characteristics were measured throughout the range of motion. After testing in the intact condition, the supraspinatus and infraspinatus were resected. The cuff tear was then repaired by latissimus dorsi transfer. Two muscle loading conditions were applied after latissimus transfer to simulate increased tension that may occur due to limited muscle excursion. A repeated-measures analysis of variance was used for statistical analysis. The amount of internal rotation due to muscle loading and maximum internal rotation increased with massive cuff tear and was restored with latissimus transfer (P < .05). At maximum internal rotation, the humeral head apex shifted anteriorly, superiorly, and laterally at 0° of abduction after massive cuff tear (P < .05); this abnormal shift was corrected with latissimus transfer (P < .05). However, at 30° and 60° of abduction, latissimus transfer significantly altered kinematics (P < .05) and latissimus transfer with increased muscle loading increased contact pressure, especially at 60° of abduction. Latissimus dorsi transfer is beneficial in restoring humeral internal/external rotational range of motion, the internal/external rotational balance of the humerus, and glenohumeral kinematics at 0° of abduction. However, latissimus dorsi transfer with simulated limited excursion may lead to an overcompensation that can further deteriorate normal biomechanics, especially at higher abduction angles. Published by Mosby, Inc.

Bilateral Cavernous Nerve Crush Injury in the Rat Model: A Comparative Review of Pharmacologic Interventions.

PubMed

Haney, Nora M; Nguyen, Hoang M T; Honda, Matthew; Abdel-Mageed, Asim B; Hellstrom, Wayne J G

2018-04-01

It is common for men to develop erectile dysfunction after radical prostatectomy. The anatomy of the rat allows the cavernous nerve (CN) to be identified, dissected, and injured in a controlled fashion. Therefore, bilateral CN injury (BCNI) in the rat model is routinely used to study post-prostatectomy erectile dysfunction. To compare and contrast the available literature on pharmacologic intervention after BCNI in the rat. A literature search was performed on PubMed for cavernous nerve and injury and erectile dysfunction and rat. Only articles with BCNI and pharmacologic intervention that could be grouped into categories of immune modulation, growth factor therapy, receptor kinase inhibition, phosphodiesterase type 5 inhibition, and anti-inflammatory and antifibrotic interventions were included. To assess outcomes of pharmaceutical intervention on erectile function recovery after BCNI in the rat model. The ratio of maximum intracavernous pressure to mean arterial pressure was the main outcome measure chosen for this analysis. All interventions improved erectile function recovery after BCNI based on the ratio of maximum intracavernous pressure to mean arterial pressure results. Additional end-point analysis examined the corpus cavernosa and/or the major pelvic ganglion and CN. There was extreme heterogeneity within the literature, making accurate comparisons between crush injury and therapeutic interventions difficult. BCNI in the rat is the accepted animal model used to study nerve-sparing post-prostatectomy erectile dysfunction. However, an important limitation is extreme variability. Efforts should be made to decrease this variability and increase the translational utility toward clinical trials in humans. Haney NM, Nguyen HMT, Honda M, et al. Bilateral Cavernous Nerve Crush Injury in the Rat Model: A Comparative Review of Pharmacologic Interventions. Sex Med Rev 2018;6:234-241. Copyright © 2017 International Society for Sexual Medicine. Published by Elsevier Inc. All rights reserved.

Studies on unsteady pressure fields in the region of separating and reattaching flows

NASA Astrophysics Data System (ADS)

Govinda Ram, H. S.; Arakeri, V. H.

1990-12-01

Experimental studies on the measurement of pressure fields in the region of separating and reattaching flows behind several two-dimensional fore-bodies and one axisymmetric body are reported. In particular, extensive measurements of mean pressure, surface pressure fluctuation, and pressure fluctuation within the flow were made for a series of two-dimensional fore-body shapes consisting of triangular nose with varying included angle. The measurements from different bodies are compared and one of the important findings is that the maximum values of rms pressure fluctuation levels in the shear layer approaching reattachment are almost equal to the maximum value of the surface fluctuation levels.

Design of a very-low-bleed Mach 2.5 mixed-compression inlet with 45 percent internal contraction

NASA Technical Reports Server (NTRS)

Wasserbauer, J. F.; Shaw, R. J.; Neumann, H. E.

1975-01-01

A full-scale, mixed-compression inlet was designed for operation with the TF30-P-3 turbofan engine and tested at Mach numbers of 2.5 and 2.0. The two-cone axisymmetric inlet had minimum internal contraction consistent with high total pressure recovery and low cowl drag. At Mach 2.5, inlet recovery was 0.906 with only 0.021 centerbody bleed mass-flow ratio and no cowl bleed. Increased centerbody bleed gave a maximum inlet unstart angle of attack of 6.85 deg. At Mach 2.0, inlet recovery was 0.94 with only 0.014 centerbody bleed mass-flow ratio and no cowl bleed. Inlet performance and angle-of-attack tolerance is presented for operation at Mach numbers of 2.5 and 2.0.

40 CFR Table 2 to Subpart Ggggg of... - Control Levels as Required by § 63.7895(a) for Tanks Managing Remediation Material With a Maximum...

Code of Federal Regulations, 2010 CFR

2010-07-01

....7895(a) for Tanks Managing Remediation Material With a Maximum HAP Vapor Pressure Less Than 76.6 kPa 2... CATEGORIES (CONTINUED) National Emission Standards for Hazardous Air Pollutants: Site Remediation Pt. 63... Tanks Managing Remediation Material With a Maximum HAP Vapor Pressure Less Than 76.6 kPa If your tank...

Low-level nocturnal wind maximum over the Central Amazon Basin

NASA Technical Reports Server (NTRS)

Greco, Steven; Ulanski, Stanley; Garstang, Michael; Houston, Samuel

1992-01-01

A low-level nocturnal wind maximum is shown to exist over extensive and nearly undisturbed rainforest near the central Amazon city of Manaus. Meteorological data indicate the presence of this nocturnal wind maximum during both the wet and dry seasons of the Central Amazon Basin. Daytime wind speeds which are characteristically 3-7 m/s between 300 and 1000 m increase to 10-15 m/s shortly after sunset. The wind-speed maximum is reached in the early evening, with wind speeds remaining high until several hours after sunrise. The nocturnal wind maximum is closely linked to a strong low-level inversion formed by radiational cooling of the rainforest canopy. Surface and low-level pressure gradients between the undisturbed forest and the large Amazon river system and the city of Manaus are shown to be responsible for much of the nocturnal wind increase. The pressure gradients are interpreted as a function of the thermal differences between undisturbed forest and the river/city. The importance of both the frictional decoupling and the horizontal pressure gradient suggest that the nocturnal wind maximum does not occur uniformly over all Amazonia. Low-level winds are thought to be pervasive under clear skies and strong surface cooling and that, in many places (i.e., near rivers), local pressure gradients enhance the low-level nocturnal winds.

A high-performance gradient insert for rapid and short-T2 imaging at full duty cycle.

PubMed

Weiger, Markus; Overweg, Johan; Rösler, Manuela Barbara; Froidevaux, Romain; Hennel, Franciszek; Wilm, Bertram Jakob; Penn, Alexander; Sturzenegger, Urs; Schuth, Wout; Mathlener, Menno; Borgo, Martino; Börnert, Peter; Leussler, Christoph; Luechinger, Roger; Dietrich, Benjamin Emanuel; Reber, Jonas; Brunner, David Otto; Schmid, Thomas; Vionnet, Laetitia; Pruessmann, Klaas P

2018-06-01

The goal of this study was to devise a gradient system for MRI in humans that reconciles cutting-edge gradient strength with rapid switching and brings up the duty cycle to 100% at full continuous amplitude. Aiming to advance neuroimaging and short-T 2 techniques, the hardware design focused on the head and the extremities as target anatomies. A boundary element method with minimization of power dissipation and stored magnetic energy was used to design anatomy-targeted gradient coils with maximally relaxed geometry constraints. The design relies on hollow conductors for high-performance cooling and split coils to enable dual-mode gradient amplifier operation. With this approach, strength and slew rate specifications of either 100 mT/m with 1200 mT/m/ms or 200 mT/m with 600 mT/m/ms were reached at 100% duty cycle, assuming a standard gradient amplifier and cooling unit. After manufacturing, the specified values for maximum gradient strength, maximum switching rate, and field geometry were verified experimentally. In temperature measurements, maximum local values of 63°C were observed, confirming that the device can be operated continuously at full amplitude. Testing for peripheral nerve stimulation showed nearly unrestricted applicability in humans at full gradient performance. In measurements of acoustic noise, a maximum average sound pressure level of 132 dB(A) was determined. In vivo capability was demonstrated by head and knee imaging. Full gradient performance was employed with echo planar and zero echo time readouts. Combining extreme gradient strength and switching speed without duty cycle limitations, the described system offers unprecedented options for rapid and short-T 2 imaging. Magn Reson Med 79:3256-3266, 2018. © 2017 International Society for Magnetic Resonance in Medicine. © 2017 International Society for Magnetic Resonance in Medicine.

Two optimal working regimes of the ”long” Iguasu gas centrifuge

NASA Astrophysics Data System (ADS)

Borman, V. D.; Bogovalov, S. V.; Borisevich, V. D.; Tronin, I. V.; Tronin, V. N.

2016-09-01

We argue on the basis of the results of optimization calculations that the dependence of the optimal separative power of the Iguasu gas centrifuge with 2 m rotor has two local maxima,corresponding pressures of p max1 = 35 mmHg and p max2 = 350 mmHg. The optimal separative power values in these maxima differ by the value of 0.6%. Low pressure maximum is caused by the thermal drive, whereas high pressure maximum is caused by both thermal and mechanical drives. High pressure maximum is located on wide ’’plateau” from p 1 = 200 mmHg to p 2 = 500 mmHg, where the optimal separative power changes in the range of 0.7%. In this way, Iguasu gas centrifuge has two optimal working regimes with different sets of working parameters and close slightly different values of the separative power. Calculations show that high pressure regime is less sensitive to the parameters change than low pressure one.

Performance of a green propellant thruster with discharge plasma

NASA Astrophysics Data System (ADS)

Shindo, Takahiro; Wada, Asato; Maeda, Hiroshi; Watanabe, Hiroki; Takegahara, Haruki

2017-02-01

A discharge plasma was applied to initiate the combustion of a hydroxylammonium nitrate-based propellant as a substitute for the catalysts that are typically employed. The resulting thrust and thrust-to-power ratio during short interval firing tests as well as the chamber pressure with a single pulse discharge were evaluated. A 1.5-s firing test generated a maximum thrust of 322 mN along with a thrust-to-power ratio of 0.95 mN/W. During the single-pulse discharge trials, pulsed discharge capacitor energies of 5.4, 10.8, and 16.4 J were assessed, and the maximum chamber pressure was found to increase as the energy was raised. The maximum chamber pressures varied widely between experimental trials, and a 16.4-J energy value resulted in the highest chamber pressure of over 1 MPaG. The time spans between the pulsed discharge and the peak chamber pressure were in the range of 1-2 ms, representing a chamber pressure increase rate much higher than those obtained with standard catalysts.

The effect of long and short head biceps loading on glenohumeral joint rotational range of motion and humeral head position.

PubMed

McGarry, Michelle H; Nguyen, Michael L; Quigley, Ryan J; Hanypsiak, Bryan; Gupta, Ranjan; Lee, Thay Q

2016-06-01

To evaluate the effect of loading the long and short heads of the biceps on glenohumeral range of motion and humeral head position. Eight cadaveric shoulders were tested in 60° abduction in the scapula and coronal plane. Muscle loading was applied based on cross-sectional area ratios. The short and long head of the biceps were loaded individually followed by combined loading. Range of motion was measured with 2.2 Nm torque, and the humeral head apex position was measured using a MicroScribe. A paired t test with Bonferroni correction was used for statistics. Long head loading decreased internal rotation in both the scapular (17.9 %) and coronal planes (5.7 %) and external rotation in the scapular plane (2.6 %) (P < 0.04). With only short head loading, maximum internal rotation was significantly increased in the scapular and coronal plane. Long head and short head loading shifted the humeral head apex posteriorly in maximum internal rotation in both planes with the long head shift being significantly greater than the short head. Long head loading also shifted the humeral apex inferiorly in internal rotation and inferiorly posteriorly in neutral rotation in the scapular plane. With the long head unloaded, there was a significant superior shift with short head loading in both planes. Loading the long head of the biceps had a much greater effect on glenohumeral range of motion and humeral head shift than the short head of the biceps; however, in the absence of long head loading, with the short head loaded, maximum internal rotation increases and the humeral head shifts superiorly, which may contribute to impingement following tenodesis of the long head of the biceps. These small changes in rotational range of motion and humeral head position with biceps tenodesis may not lead to pathologic conditions in low-demand patients; however, in throwers, biceps tenodesis may lead to increased contact pressures in late-cocking and deceleration that will likely translate to decreased performance therefore every effort should be made to preserve the biceps-labral complex.

Internal shocks in microquasar jets with a continuous Lorentz factor modulation

NASA Astrophysics Data System (ADS)

Pjanka, Patryk; Stone, James M.

2018-06-01

We perform relativistic hydrodynamic simulations of internal shocks formed in microquasar jets by continuous variation of the bulk Lorentz factor, in order to investigate the internal shock model. We consider one-, two-, and flicker noise 20-mode variability. We observe emergence of a forward-reverse shock structure for each peak of the Lorentz factor modulation. The high pressure in the shocked layer launches powerful outflows perpendicular to the jet beam into the ambient medium. These outflows dominate the details of the jet's kinetic energy thermalization. They are responsible for mixing between the jet and the surrounding medium and generate powerful shocks in the latter. These results do not concur with the popular picture of well-defined internal shells depositing energy as they collide within the confines of the jet, in fact collisions between internal shells themselves are quite rare in our continuous formulation of the problem. For each of our simulations, we calculate the internal energy deposited in the system, the `efficiency' of this deposition (defined as the ratio of internal to total flow energy), and the maximum temperature reached in order to make connections to emission mechanisms. We probe the dependence of these diagnostics on the Lorentz factor variation amplitudes, modulation frequencies, as well as the initial density ratio between the jet and the ambient medium.

Impacts of an Ammonia Leak on the Cabin Atmosphere of the International Space Station

NASA Technical Reports Server (NTRS)

Duchesne, Stephanie M.; Sweterlitsch, Jeff J.; Son, Chang H.; Perry, Jay L.

2011-01-01

Toxic chemical release into the cabin atmosphere is one of the three major emergency scenarios identified on the International Space Station (ISS). The release of anhydrous ammonia, the coolant used in the U.S. On-orbit Segment (USOS) External Active Thermal Control Subsystem (EATCS), into the ISS cabin atmosphere is one of the most serious toxic chemical release cases identified on board ISS. The USOS Thermal Control System (TCS) includes an Internal Thermal Control Subsystem (ITCS) water loop and an EATCS ammonia loop that transfer heat at the interface heat exchanger (IFHX). Failure modes exist that could cause a breach within the IFHX. This breach would result in high pressure ammonia from the EATCS flowing into the lower pressure ITCS water loop. As the pressure builds in the ITCS loop, it is likely that the gas trap, which has the lowest maximum design pressure within the ITCS, would burst and cause ammonia to enter the ISS atmosphere. It is crucial to first characterize the release of ammonia into the ISS atmosphere in order to develop methods to properly mitigate the environmental risk. This paper will document the methods used to characterize an ammonia leak into the ISS cabin atmosphere. A mathematical model of the leak was first developed in order to define the flow of ammonia into the ISS cabin atmosphere based on a series of IFHX rupture cases. Computational Fluid Dynamics (CFD) methods were then used to model the dispersion of the ammonia throughout the ISS cabin and determine localized effects and ventilation effects on the dispersion of ammonia. Lastly, the capabilities of the current on-orbit systems to remove ammonia were reviewed and scrubbing rates of the ISS systems were defined based on the ammonia release models. With this full characterization of the release of ammonia from the USOS TCS, an appropriate mitigation strategy that includes crew and system emergency response procedures, personal protection equipment use, and atmosphere monitoring and scrubbing hardware can be established.

Impacts of an Ammonia Leak on the Cabin Atmosphere of the International Space Station

NASA Technical Reports Server (NTRS)

Duchesne, Stephanie M.; Sweterlitsch, Jeffrey J.; Son, Chang H.; Perry Jay L.

2012-01-01

Toxic chemical release into the cabin atmosphere is one of the three major emergency scenarios identified on the International Space Station (ISS). The release of anhydrous ammonia, the coolant used in the U.S. On-orbit Segment (USOS) External Active Thermal Control Subsystem (EATCS), into the ISS cabin atmosphere is one of the most serious toxic chemical release cases identified on board ISS. The USOS Thermal Control System (TCS) includes an Internal Thermal Control Subsystem (ITCS) water loop and an EATCS ammonia loop that transfer heat at the interface heat exchanger (IFHX). Failure modes exist that could cause a breach within the IFHX. This breach would result in high pressure ammonia from the EATCS flowing into the lower pressure ITCS water loop. As the pressure builds in the ITCS loop, it is likely that the gas trap, which has the lowest maximum design pressure within the ITCS, would burst and cause ammonia to enter the ISS atmosphere. It is crucial to first characterize the release of ammonia into the ISS atmosphere in order to develop methods to properly mitigate the environmental risk. This paper will document the methods used to characterize an ammonia leak into the ISS cabin atmosphere. A mathematical model of the leak was first developed in order to define the flow of ammonia into the ISS cabin atmosphere based on a series of IFHX rupture cases. Computational Fluid Dynamics (CFD) methods were then used to model the dispersion of the ammonia throughout the ISS cabin and determine localized effects and ventilation effects on the dispersion of ammonia. Lastly, the capabilities of the current on-orbit systems to remove ammonia were reviewed and scrubbing rates of the ISS systems were defined based on the ammonia release models. With this full characterization of the release of ammonia from the USOS TCS, an appropriate mitigation strategy that includes crew and system emergency response procedures, personal protection equipment use, and atmosphere monitoring and scrubbing hardware can be established.

14 CFR Appendix C to Part 135 - Helicopter Flight Recorder Specifications

Code of Federal Regulations, 2012 CFR

2012-01-01

... Maximum range +5% 1 1% 2 Engine torque Maximum range ±5% 1 1% 2 Flight Control—Hydraulic Pressure Primary... kts., whichever is greater 1 1 kt. Altitude −1,000 ft. to 20,000 ft. pressure altitude ±100 to ±700 ft...

40 CFR 60.113 - Monitoring of operations.

Code of Federal Regulations, 2011 CFR

2011-07-01

... petroleum liquid stored, the period of storage, and the maximum true vapor pressure of that liquid during the respective storage period. (b) Available data on the typical Reid vapor pressure and the maximum... (CONTINUED) STANDARDS OF PERFORMANCE FOR NEW STATIONARY SOURCES Standards of Performance for Storage Vessels...

40 CFR 60.115a - Monitoring of operations.

Code of Federal Regulations, 2010 CFR

2010-07-01

... petroleum liquid stored, the period of storage, and the maximum true vapor pressure of that liquid during the respective storage period. (b) Available data on the typical Reid vapor pressure and the maximum... (CONTINUED) STANDARDS OF PERFORMANCE FOR NEW STATIONARY SOURCES Standards of Performance for Storage Vessels...

40 CFR 60.115a - Monitoring of operations.

Code of Federal Regulations, 2012 CFR

2012-07-01

... petroleum liquid stored, the period of storage, and the maximum true vapor pressure of that liquid during the respective storage period. (b) Available data on the typical Reid vapor pressure and the maximum... (CONTINUED) STANDARDS OF PERFORMANCE FOR NEW STATIONARY SOURCES Standards of Performance for Storage Vessels...

40 CFR 60.113 - Monitoring of operations.

Code of Federal Regulations, 2013 CFR

2013-07-01

... petroleum liquid stored, the period of storage, and the maximum true vapor pressure of that liquid during the respective storage period. (b) Available data on the typical Reid vapor pressure and the maximum... (CONTINUED) STANDARDS OF PERFORMANCE FOR NEW STATIONARY SOURCES Standards of Performance for Storage Vessels...

40 CFR 60.115a - Monitoring of operations.

Code of Federal Regulations, 2013 CFR

2013-07-01

... petroleum liquid stored, the period of storage, and the maximum true vapor pressure of that liquid during the respective storage period. (b) Available data on the typical Reid vapor pressure and the maximum... (CONTINUED) STANDARDS OF PERFORMANCE FOR NEW STATIONARY SOURCES Standards of Performance for Storage Vessels...

40 CFR 60.113 - Monitoring of operations.

Code of Federal Regulations, 2014 CFR

2014-07-01

... petroleum liquid stored, the period of storage, and the maximum true vapor pressure of that liquid during the respective storage period. (b) Available data on the typical Reid vapor pressure and the maximum... (CONTINUED) STANDARDS OF PERFORMANCE FOR NEW STATIONARY SOURCES Standards of Performance for Storage Vessels...

40 CFR 60.113 - Monitoring of operations.

Code of Federal Regulations, 2012 CFR

2012-07-01

... petroleum liquid stored, the period of storage, and the maximum true vapor pressure of that liquid during the respective storage period. (b) Available data on the typical Reid vapor pressure and the maximum... (CONTINUED) STANDARDS OF PERFORMANCE FOR NEW STATIONARY SOURCES Standards of Performance for Storage Vessels...

40 CFR 60.115a - Monitoring of operations.

Code of Federal Regulations, 2014 CFR

2014-07-01

... petroleum liquid stored, the period of storage, and the maximum true vapor pressure of that liquid during the respective storage period. (b) Available data on the typical Reid vapor pressure and the maximum... (CONTINUED) STANDARDS OF PERFORMANCE FOR NEW STATIONARY SOURCES Standards of Performance for Storage Vessels...

40 CFR 60.115a - Monitoring of operations.

Code of Federal Regulations, 2011 CFR

2011-07-01

... petroleum liquid stored, the period of storage, and the maximum true vapor pressure of that liquid during the respective storage period. (b) Available data on the typical Reid vapor pressure and the maximum... (CONTINUED) STANDARDS OF PERFORMANCE FOR NEW STATIONARY SOURCES Standards of Performance for Storage Vessels...

40 CFR 60.113 - Monitoring of operations.

Code of Federal Regulations, 2010 CFR

2010-07-01

... petroleum liquid stored, the period of storage, and the maximum true vapor pressure of that liquid during the respective storage period. (b) Available data on the typical Reid vapor pressure and the maximum... (CONTINUED) STANDARDS OF PERFORMANCE FOR NEW STATIONARY SOURCES Standards of Performance for Storage Vessels...

RSRM and ETM03 Internal Flow Simulations and Comparisons

NASA Technical Reports Server (NTRS)

Ahmad, R. A.; Morstadt, R. A.; Eaton, A. M.

2003-01-01

ETM03 (Engineering Test Motor-03) is an extended length RSRM (Reusable Solid Rocket Motor) designed to increase motor performance and create more severe internal environments compared with the standard four-segment RSRM motor configuration. This is achieved primarily through three unique design features. First is the incorporation of an additional RSRM center segment, second is a slight increase in throat diameter, and third is the use of an Extended Aft Exit Cone (EAEC). As a result of these design features, parameters such as web time, action time, head end pressure, web time average pressure, maximum thrust, mass flow rate, centerline Mach number, pressure and thrust integrals have all increased compared with nominal RSRM values. In some cases these increases are substantial. The primary objective of the ETM03 test program is to provide a platform for RSRM component margin testing. Test results will not only provide direct data concerning component performance under more adverse conditions, but serve as a second design data point for developing, validating and enhancing component analytical modeling techniques. To help component designers assess how the changes in motor environment will affect performance, internal flow simulations for both the nominal RSRM and ETM03 motor designs were completed to obtain comparisons of aero-thermal boundary conditions and system loads. Full geometries for both motors were characterized with two-dimensional axi-symmetric models at burn times of 1, 20, 54, 67 and 80-seconds. A sixth set considered burn times of 110 and 117-seconds for RSRM and ETM03, respectively. The simulations were performed using the computational fluid dynamics (CFD) commercial code FLUENT (trademark). Of particular interest were any differences between the two motor environments that could lead to a significant increase in system loads, or in internal insulation and/or nozzle component charring and erosion in ETM03 compared with RSRM. Based on these comparative analyses conducted in this study, the objective of ETM03 will be achieved by providing a more adverse operating environment for motor components than the nominal RSRM environment. For example: Higher chamber pressure drop in ETM03 than in RSRM; higher centerline Mach numbers approaching the nozzle in ETM03 than in RSRM; higher heat transfer rates for the internal insulation and nozzle components in ETM03 than in RSRM; and higher levels of droplet impingement and slag accumulation in ETM03 than in the RSRM.

The Effect of Valve Cooling upon Maximum Permissible Engine Output as Limited by Knock

NASA Technical Reports Server (NTRS)

Munger, Maurice; Wilsted, H D; Mulcahy, B A

1942-01-01

A Wright GR-1820-G200 cylinder was tested over a wide range of fuel-air ratios at maximum permissible power output as limited by knock with three different degrees of valve cooling. The valves used were stock valves (solid inlet valve and hollow sodium-cooled exhaust valve), hollow valves with no coolant, and hollow valves with flowing water as a coolant. Curves showing the variation in maximum permissible values of inlet-air pressure, indicated mean effective pressure, cylinder charge, and indicated specific fuel consumption with change in fuel-air ratio and valve cooling are shown. The use of valves cooled by a stream of water passing through their hollow interiors permitted indicated mean effective pressures 10 percent higher than the mean effective pressures permissible with stock valves when the engine was operated with fuel-air ratios from 0.055 to 0.065. Operation of the engine with lean mixtures with uncooled hollow valves resulted in power output below the output obtained with the stock valves. The data show an increase in maximum permissible indicated mean effective pressure due to cooling the valves, which averages only 2.1 percent with fuel-air ratios from 0.075 to 0.105.

Evaluating the effects of pentoxifylline administration on experimental pressure sores in rats by biomechanical examinations

PubMed Central

Velaei, Kobra; Torkman, Giti; Rezaie, Fatemealsadat; Amini, Abdollah; Noruzian, Mohsen; Tavassol, Azaedh; Bayat, Mehernoush

2012-01-01

This study used a biomechanical test to evaluate the effects of pentoxifylline administration on the wound healing process of an experimental pressure sore induced in rats. Under general anesthesia and sterile conditions, experimental pressure sores generated by no. 25 Halsted mosquito forceps were inflicted on 12 adult male rats. Pentoxifylline was injected intraperitoneally at a dose of 50 mg/kg daily from the day the pressure sore was generated, for a period of 20 days. At the end of 20 days, rats were sacrificed and skin samples extracted. Samples were biomechanically examined by a material testing instrument for maximum stress (N mm2), work up to maximum force (N), and elastic stiffness (N/mm). In the experimental group, maximum stress (2.05±0.15) and work up to maximum force (N/mm) (63.75±4.97) were significantly higher than the control group (1.3±0.27 and 43.3±14.96, P=0.002 and P=0.035, respectively). Pentoxifylline administration significantly accelerated the wound healing process in experimental rats with pressure sores, compared to that of the control group. PMID:23091522

Evaluating the effects of pentoxifylline administration on experimental pressure sores in rats by biomechanical examinations.

PubMed

Velaei, Kobra; Bayat, Mohammad; Torkman, Giti; Rezaie, Fatemealsadat; Amini, Abdollah; Noruzian, Mohsen; Tavassol, Azaedh; Bayat, Mehernoush

2012-09-01

This study used a biomechanical test to evaluate the effects of pentoxifylline administration on the wound healing process of an experimental pressure sore induced in rats. Under general anesthesia and sterile conditions, experimental pressure sores generated by no. 25 Halsted mosquito forceps were inflicted on 12 adult male rats. Pentoxifylline was injected intraperitoneally at a dose of 50 mg/kg daily from the day the pressure sore was generated, for a period of 20 days. At the end of 20 days, rats were sacrificed and skin samples extracted. Samples were biomechanically examined by a material testing instrument for maximum stress (N mm(2)), work up to maximum force (N), and elastic stiffness (N/mm). In the experimental group, maximum stress (2.05±0.15) and work up to maximum force (N/mm) (63.75±4.97) were significantly higher than the control group (1.3±0.27 and 43.3±14.96, P=0.002 and P=0.035, respectively). Pentoxifylline administration significantly accelerated the wound healing process in experimental rats with pressure sores, compared to that of the control group.

49 CFR 192.620 - Alternative maximum allowable operating pressure for certain steel pipelines.

Code of Federal Regulations, 2014 CFR

2014-10-01

... for certain steel pipelines. 192.620 Section 192.620 Transportation Other Regulations Relating to... STANDARDS Operations § 192.620 Alternative maximum allowable operating pressure for certain steel pipelines..., 2, or 3 location; (2) The pipeline segment is constructed of steel pipe meeting the additional...

49 CFR 192.620 - Alternative maximum allowable operating pressure for certain steel pipelines.

Code of Federal Regulations, 2011 CFR

2011-10-01

... of a maximum allowable operating pressure based on higher stress levels in the following areas: Take... pipeline at the increased stress level under this section with conventional operation; and (ii) Describe... targeted audience; and (B) Include information about the integrity management activities performed under...

49 CFR 192.620 - Alternative maximum allowable operating pressure for certain steel pipelines.

Code of Federal Regulations, 2013 CFR

2013-10-01

... of a maximum allowable operating pressure based on higher stress levels in the following areas: Take... pipeline at the increased stress level under this section with conventional operation; and (ii) Describe... targeted audience; and (B) Include information about the integrity management activities performed under...

49 CFR 192.620 - Alternative maximum allowable operating pressure for certain steel pipelines.

Code of Federal Regulations, 2012 CFR

2012-10-01

... of a maximum allowable operating pressure based on higher stress levels in the following areas: Take... pipeline at the increased stress level under this section with conventional operation; and (ii) Describe... targeted audience; and (B) Include information about the integrity management activities performed under...

The influence of low and high pressure levels during negative-pressure wound therapy on wound contraction and fluid evacuation.

PubMed

Borgquist, Ola; Ingemansson, Richard; Malmsjö, Malin

2011-02-01

Negative-pressure wound therapy promotes healing by drainage of excessive fluid and debris and by mechanical deformation of the wound. The most commonly used negative pressure, -125 mmHg, may cause pain and ischemia, and the pressure often needs to be reduced. The aim of the present study was to examine wound contraction and fluid removal at different levels of negative pressure. Peripheral wounds were created in 70-kg pigs. The immediate effects of negative-pressure wound therapy (-10 to -175 mmHg) on wound contraction and fluid removal were studied in eight pigs. The long-term effects on wound contraction were studied in eight additional pigs during 72 hours of negative-pressure wound therapy at -75 mmHg. Wound contraction and fluid removal increased gradually with increasing levels of negative pressure until reaching a steady state. Maximum wound contraction was observed at -75 mmHg. When negative-pressure wound therapy was discontinued, after 72 hours of therapy, the wound surface area was smaller than before therapy. Maximum wound fluid removal was observed at -125 mmHg. Negative-pressure wound therapy facilitates drainage of wound fluid and exudates and results in mechanical deformation of the wound edge tissue, which is known to stimulate granulation tissue formation. Maximum wound contraction is achieved already at -75 mmHg, and this may be a suitable pressure for most wounds. In wounds with large volumes of exudate, higher pressure levels may be needed for the initial treatment period.

Fragment Production and Survival in Irradiated Disks: A Comprehensive Cooling Criterion

NASA Astrophysics Data System (ADS)

Kratter, Kaitlin M.; Murray-Clay, Ruth A.

2011-10-01

Accretion disks that become gravitationally unstable can fragment into stellar or substellar companions. The formation and survival of these fragments depends on the precarious balance between self-gravity, internal pressure, tidal shearing, and rotation. Disk fragmentation depends on two key factors: (1) whether the disk can get to the fragmentation boundary of Q = 1 and (2) whether fragments can survive for many orbital periods. Previous work suggests that to reach Q = 1, and have fragments survive, a disk must cool on an orbital timescale. Here we show that disks heated primarily by external irradiation always satisfy the standard cooling time criterion. Thus, even though irradiation heats disks and makes them more stable in general, once they reach the fragmentation boundary, they fragment more easily. We derive a new cooling criterion that determines fragment survival and calculate a pressure-modified Hill radius, which sets the maximum size of pressure-supported objects in a Keplerian disk. We conclude that fragmentation in protostellar disks might occur at slightly smaller radii than previously thought and recommend tests for future simulations that will better predict the outcome of fragmentation in real disks.

Multi-bottle, no compressor, mean pressure control system for a Stirling engine

DOEpatents

Corey, John A.

1990-01-01

The invention relates to an apparatus for mean pressure control of a Stirling engine without the need for a compressor. The invention includes a multi-tank system in which there is at least one high pressure level tank and one low pressure level tank wherein gas flows through a maximum pressure and supply line from the engine to the high pressure tank when a first valve is opened until the maximum pressure of the engine drops below that of the high pressure tank opening an inlet regulator to permit gas flow from the engine to the low pressure tank. When gas flows toward the engine it flows through the minimum pressure supply line 2 when a second valve is opened from the low pressure tank until the tank reaches the engine's minimum pressure level at which time the outlet regulator opens permitting gas to be supplied from the high pressure tank to the engine. Check valves between the two tanks prevent any backflow of gas from occurring.

Effect of the NACA Injection Impeller on the Mixture Distribution of a Double-row Radial Aircraft Engine

NASA Technical Reports Server (NTRS)

Marble, Frank E.; Ritter, William K.; Miller, Mahlon A.

1946-01-01

For the normal range of engine power the impeller provided marked improvement over the standard spray-bar injection system. Mixture distribution at cruising was excellent, maximum cylinder temperatures were reduced about 30 degrees F, and general temperature distribution was improved. The uniform mixture distribution restored the normal response of cylinder temperature to mixture enrichment and it reduced the possibility of carburetor icing, while no serious loss in supercharger pressure rise resulted from injection of fuel near the impeller outlet. The injection impeller also furnished a convenient means of adding water to the charge mixture for internal cooling.

Increased in-shoe lateral plantar pressures with chronic ankle instability.

PubMed

Schmidt, Heather; Sauer, Lindsay D; Lee, Sae Yong; Saliba, Susan; Hertel, Jay

2011-11-01

Previous plantar pressure research found increased loads and slower loading response on the lateral aspect of the foot during gait with chronic ankle instability compared to healthy controls. The studies had subjects walking barefoot over a pressure mat and results have not been confirmed with an in-shoe plantar pressure system. Our purpose was to report in-shoe plantar pressure measures for chronic ankle instability subjects compared to healthy controls. Forty-nine subjects volunteered (25 healthy controls, 24 chronic ankle instability) for this case-control study. Subjects jogged continuously on a treadmill at 2.68 m/s (6.0 mph) while three trials of ten consecutive steps were recorded. Peak pressure, time-to-peak pressure, pressure-time integral, maximum force, time-to-maximum force, and force-time integral were assessed in nine regions of the foot with the Pedar-x in-shoe plantar pressure system (Novel, Munich, Germany). Chronic ankle instability subjects demonstrated a slower loading response in the lateral rearfoot indicated by a longer time-to-peak pressure (16.5% +/- 10.1, p = 0.001) and time-to-maximum force (16.8% +/- 11.3, p = 0.001) compared to controls (6.5% +/- 3.7 and 6.6% +/- 5.5, respectively). In the lateral midfoot, ankle instability subjects demonstrated significantly greater maximum force (318.8 N +/- 174.5, p = 0.008) and peak pressure (211.4 kPa +/- 57.7, p = 0.008) compared to controls (191.6 N +/- 74.5 and 161.3 kPa +/- 54.7). Additionally, ankle instability subjects demonstrated significantly higher force-time integral (44.1 N/s +/- 27.3, p = 0.005) and pressure-time integral (35.0 kPa/s +/- 12.0, p = 0.005) compared to controls (23.3 N/s +/- 10.9 and 24.5 kPa/s +/- 9.5). In the lateral forefoot, ankle instability subjects demonstrated significantly greater maximum force (239.9N +/- 81.2, p = 0.004), force-time integral (37.0 N/s +/- 14.9, p = 0.003), and time-to-peak pressure (51.1% +/- 10.9, p = 0.007) compared to controls (170.6 N +/- 49.3, 24.3 N/s +/- 7.2 and 43.8% +/- 4.3). Using an in-shoe plantar pressure system, chronic ankle instability subjects had greater plantar pressures and forces in the lateral foot compared to controls during jogging. These findings may have implications in the etiology and treatment of chronic ankle instability.

Design of a Two-Stage Light Gas Gun for Muzzle Velocities of 10 - 11 kms

NASA Technical Reports Server (NTRS)

Bogdanoff, David W.

2016-01-01

Space debris poses a major risk to spacecraft. In low earth orbit, impact velocities can be 10 11 kms and as high as 15 kms. For debris shield design, it would be desirable to be able to launch controlled shape projectiles to these velocities. The design of the proposed 10 11 kmsec gun uses, as a starting point, the Ames 1.280.22 two stage gun, which has achieved muzzle velocities of 10 11.3 kmsec. That gun is scaled up to a 0.3125 launch tube diameter. The gun is then optimized with respect to maximum pressures by varying the pump tube length to diameter ratio (LD), the piston mass and the hydrogen pressure. A pump tube LD of 36.4 is selected giving the best overall performance. Piezometric ratios for the optimized guns are found to be 2.3, much more favorable than for more traditional two stage light gas guns, which range from 4 to 6. The maximum powder chamber pressures are 20 to 30 ksi. To reduce maximum pressures, the desirable range of the included angle of the cone of the high pressure coupling is found to be 7.3 to 14.6 degrees. Lowering the break valve rupture pressure is found to lower the maximum projectile base pressure, but to raise the maximum gun pressure. For the optimized gun with a pump tube LD of 36.4, increasing the muzzle velocity by decreasing the projectile mass and increasing the powder loads is studied. It appears that saboted spheres could be launched to 10.25 and possibly as high as 10.7 10.8 kmsec, and that disc-like plastic models could be launched to 11.05 kms. The use of a tantalum liner to greatly reduce bore erosion and increase muzzle velocity is discussed. With a tantalum liner, CFD code calculations predict muzzle velocities as high as 12 to 13 kms.

Extubation process in bed-ridden elderly intensive care patients receiving inspiratory muscle training: a randomized clinical trial.

PubMed

Cader, Samária Ali; de Souza Vale, Rodrigo Gomes; Zamora, Victor Emmanuel; Costa, Claudia Henrique; Dantas, Estélio Henrique Martin

2012-01-01

The purpose of this study was to evaluate the extubation process in bed-ridden elderly intensive care patients receiving inspiratory muscle training (IMT) and identify predictors of successful weaning. Twenty-eight elderly intubated patients in an intensive care unit were randomly assigned to an experimental group (n = 14) that received conventional physiotherapy plus IMT with a Threshold IMT(®) device or to a control group (n = 14) that received only conventional physiotherapy. The experimental protocol for muscle training consisted of an initial load of 30% maximum inspiratory pressure, which was increased by 10% daily. The training was administered for 5 minutes, twice daily, 7 days a week, with supplemental oxygen from the beginning of weaning until extubation. Successful extubation was defined by the ventilation time measurement with noninvasive positive pressure. A vacuum manometer was used for measurement of maximum inspiratory pressure, and the patients' Tobin index values were measured using a ventilometer. The maximum inspiratory pressure increased significantly (by 7 cm H(2)O, 95% confidence interval [CI] 4-10), and the Tobin index decreased significantly (by 16 breaths/ min/L, 95% CI -26 to 6) in the experimental group compared with the control group. The Chi-squared distribution did not indicate a significant difference in weaning success between the groups (χ(2) = 1.47; P = 0.20). However, a comparison of noninvasive positive pressure time dependence indicated a significantly lower value for the experimental group (P = 0.0001; 95% CI 13.08-18.06). The receiver-operating characteristic curve showed an area beneath the curve of 0.877 ± 0.06 for the Tobin index and 0.845 ± 0.07 for maximum inspiratory pressure. The IMT intervention significantly increased maximum inspiratory pressure and significantly reduced the Tobin index; both measures are considered to be good extubation indices. IMT was associated with a reduction in noninvasive positive pressure time in the experimental group.

Cardiovascular effects of pimobendan in healthy mature horses.

PubMed

Afonso, T; Giguère, S; Rapoport, G; Barton, M H; Coleman, A E

2016-05-01

Pimobendan is an inodilator used in dogs for the management of heart failure due to myxomatous valve disease or dilated cardiomyopathy. The lack of data regarding the effects of pimobendan in horses prevents the rational use of this drug. To determine the cardiovascular effects of pimobendan in healthy mature horses. Randomised experimental study. Five horses were fasted overnight prior to receiving i.v. pimobendan (0.25 mg/kg bwt), intragastric (i.g.) pimobendan (0.25 mg/kg bwt) or i.g. placebo with a washout period of one week between each administration. Horses were instrumented for the measurement of right ventricular (RV) minimum pressure, RV maximum pressure, RV end diastolic pressure, and maximum rate of increase and decrease in RV pressure before and 0.5, 1, 2, 4, and 8 h after drug administration. Arterial blood pressure, central venous pressure, cardiac output and heart rate were measured at the same time points. Data were expressed as a maximum percentage of change over baseline values. There were no adverse effects associated with administration of pimobendan. The percentage increase in heart rate was significantly greater for horses given pimobendan i.g. (33 ± 4%) and i.v. (36 ± 14%) than for those given a placebo (-2 ± 7%). The percentage increase in maximum rate of increase in RV pressure (35 ± 36%) and the percentage decrease in minimum pressure (47 ± 24%) and end diastolic pressure (34 ± 13%) were significantly greater in horses given pimobendan i.v. than in those given placebo. Other variables measured were not significantly different between treatment groups. Pimobendan administered i.v. has positive chronotropic and inotropic effects in healthy mature horses and warrants further investigation for the treatment of heart failure in horses. © 2015 EVJ Ltd.

In Vivo Measurement of Surface Pressures and Retraction Distances Applied on Abdominal Organs During Surgery.

PubMed

Shah, Dignesh; Alderson, Andrew; Corden, James; Satyadas, Thomas; Augustine, Titus

2018-02-01

This study undertook the in vivo measurement of surface pressures applied by the fingers of the surgeon during typical representative retraction movements of key human abdominal organs during both open and hand-assisted laparoscopic surgery. Surface pressures were measured using a flexible thin-film pressure sensor for 35 typical liver retractions to access the gall bladder, 36 bowel retractions, 9 kidney retractions, 8 stomach retractions, and 5 spleen retractions across 12 patients undergoing open and laparoscopic abdominal surgery. The maximum and root mean square surface pressures were calculated for each organ retraction. The maximum surface pressures applied to these key abdominal organs are in the range 1 to 41 kPa, and the average maximum surface pressure for all organs and procedures was 14 ± 3 kPa. Surface pressure relaxation during the retraction hold period was observed. Generally, the surface pressures are higher, and the rate of surface pressure relaxation is lower, in the more confined hand-assisted laparoscopic procedures than in open surgery. Combined video footage and pressure sensor data for retraction of the liver in open surgery enabled correlation of organ retraction distance with surface pressure application. The data provide a platform to design strategies for the prevention of retraction injuries. They also form a basis for the design of next-generation organ retraction and space creation surgical devices with embedded sensors that can further quantify intraoperative retraction forces to reduce injury or trauma to organs and surrounding tissues.

A numerical method to enhance the performance of a cam-type electric motor-driven left ventricular assist device.

PubMed

Huang, Huan; Yang, Ming; Lu, Cunyue; Xu, Liang; Zhuang, Xiaoqi; Meng, Fan

2013-10-01

Pulsatile left ventricular assist devices (LVADs) driven by electric motors have been widely accepted as a treatment of heart failure. Performance enhancement with computer assistance for this kind of LVAD has seldom been reported. In this article, a numerical method is proposed to assist the design of a cam-type pump. The method requires an integrated model of an LVAD system, consisting of a motor, a transmission mechanism, and a cardiovascular circulation. Performance indices, that is, outlet pressure, outlet flow, and pump efficiency, were used to select the best cam profile from six candidates. A prototype pump connected to a mock circulatory loop (MCL) was used to calibrate the friction coefficient of the cam groove and preliminarily evaluate modeling accuracy. In vitro experiments show that the mean outlet pressure and flow can be predicted with high accuracy by the model, and gross geometries of the measurements can also be reproduced. Simulation results demonstrate that as the total peripheral resistance (TPR) is fixed at 1.1 mm Hg.s/mL, the two-cycle 2/3-rise profile is the best. Compared with other profiles, the maximum increases of pressure and flow indices are 75 and 76%, respectively, and the maximum efficiency increase is over 51%. For different TPRs (0.5∼1.5 mm Hg.s/mL) and operation intervals (0.1∼0.4 s) in counterpulsation, the conclusion is also acceptable. © 2013 Wiley Periodicals, Inc. and International Center for Artificial Organs and Transplantation.

Corroboration of in vivo cartilage pressures with implications for synovial joint tribology and osteoarthritis causation.

PubMed

Morrell, Kjirste C; Hodge, W Andrew; Krebs, David E; Mann, Robert W

2005-10-11

Pressures on normal human acetabular cartilage have been collected from two implanted instrumented femoral head hemiprostheses. Despite significant differences in subjects' gender, morphology, mobility, and coordination, in vivo pressure measurements from both subjects covered similar ranges, with maximums of 5-6 MPa in gait, and as high as 18 MPa in other movements. Normalized for subject weight and height (nMPa), for free-speed walking the maximum pressure values were 25.2 for the female subject and 24.5 for the male subject. The overall maximum nMPa values were 76.2 for the female subject during rising from a chair at 11 months postoperative and 82.3 for the male subject while descending steps at 9 months postoperative. These unique in vivo data are consistent with corresponding cadaver experiments and model analyses. The collective results, in vitro data, model studies, and now corroborating in vivo data support the self-pressurizing "weeping" theory of synovial joint lubrication and provide unique information to evaluate the influence of in vivo pressure regimes on osteoarthritis causation and the efficacy of augmentations to, and substitutions for, natural cartilage.

The Effect of Connecting-passage Diameter on the Performance of a Compression-ignition Engine with a Precombustion Chamber

NASA Technical Reports Server (NTRS)

Moore, C S; Collins, J H

1932-01-01

Results of motoring tests are presented showing the effect of passage diameter on chamber and cylinder compression pressures, maximum pressure differences, and f.m.e.p. over a speed range from 300 to 1,750 r.p.m. Results of engine performance tests are presented which show the effect of passage diameter on m.e.p., explosion pressures, specific fuel consumption, and rates of pressure rise for a range of engine speeds from 500 to 1,500 r.p.m. The cylinder compression pressure, the maximum pressure difference, and the f.m.e.p. decreased rapidly as the passage diameter increased to 29/64 inch, whereas further increase in passage diameter effected only a slight change. The most suitable passage diameter for good engine performance and operating characteristics was 29/64 inch. Passage diameter became less critical with a decrease in engine speed. Therefore, the design should be based on maximum operating speed. Optimum performance and satisfactory combustion control could not be obtained by means of any single diameter of the connecting passage.

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

Laurinat, J.; Kesterson, M.; Hensel, S.

The documented safety analysis for the Savannah River Site evaluates the consequences of a postulated 1000 °C fire in a glovebox. The radiological dose consequences for a pressurized release of plutonium oxide powder during such a fire depend on the maximum pressure that is attained inside the oxide storage vial. To enable evaluation of the dose consequences, pressure transients and venting flow rates have been calculated for exposure of the storage vial to the fire. A standard B vial with a capacity of approximately 8 cc was selected for analysis. The analysis compares the pressurization rate from heating and evaporationmore » of moisture adsorbed onto the plutonium oxide contents of the vial with the pressure loss due to venting of gas through the threaded connection between the vial cap and body. Tabulated results from the analysis include maximum pressures, maximum venting velocities, and cumulative vial volumes vented during the first 10 minutes of the fire transient. Results are obtained for various amounts of oxide in the vial, various amounts of adsorbed moisture, different vial orientations, and different surface fire exposures.« less

Physical understanding of the tropical cyclone wind-pressure relationship.

PubMed

Chavas, Daniel R; Reed, Kevin A; Knaff, John A

2017-11-08

The relationship between the two common measures of tropical cyclone intensity, the central pressure deficit and the peak near-surface wind speed, is a long-standing problem in tropical meteorology that has been approximated empirically yet lacks physical understanding. Here we provide theoretical grounding for this relationship. We first demonstrate that the central pressure deficit is highly predictable from the low-level wind field via gradient wind balance. We then show that this relationship reduces to a dependence on two velocity scales: the maximum azimuthal-mean azimuthal wind speed and half the product of the Coriolis parameter and outer storm size. This simple theory is found to hold across a hierarchy of models spanning reduced-complexity and Earth-like global simulations and observations. Thus, the central pressure deficit is an intensity measure that combines maximum wind speed, storm size, and background rotation rate. This work has significant implications for both fundamental understanding and risk analysis, including why the central pressure better explains historical economic damages than does maximum wind speed.

Explosive decomposition of ethylene oxide at elevated condition: effect of ignition energy, nitrogen dilution, and turbulence.

PubMed

Pekalski, A A; Zevenbergen, J F; Braithwaite, M; Lemkowitz, S M; Pasman, H J

2005-02-14

Experimental and theoretical investigation of explosive decomposition of ethylene oxide (EO) at fixed initial experimental parameters (T=100 degrees C, P=4 bar) in a 20-l sphere was conducted. Safety-related parameters, namely the maximum explosion pressure, the maximum rate of pressure rise, and the Kd values, were experimentally determined for pure ethylene oxide and ethylene oxide diluted with nitrogen. The influence of the ignition energy on the explosion parameters was also studied. All these dependencies are quantified in empirical formulas. Additionally, the effect of turbulence on explosive decomposition of ethylene oxide was investigated. In contrast to previous studies, it is found that turbulence significantly influences the explosion severity parameters, mostly the rate of pressure rise. Thermodynamic models are used to calculate the maximum explosion pressure of pure and of nitrogen-diluted ethylene oxide, at different initial temperatures. Soot formation was experimentally observed. Relation between the amounts of soot formed and the explosion pressure was experimentally observed and was calculated.

46 CFR 61.15-5 - Steam piping.

Code of Federal Regulations, 2010 CFR

2010-10-01

... hydrostatic test equal to 11/4 times the maximum allowable working pressure at the same periods prescribed for boilers in § 61.05-10. The hydrostatic test shall be applied from the boiler drum to the throttle valve... should be subjected to a hydrostatic test at a pressure of 11/4 times the maximum allowable working...

Effect of Expiratory Resistive Loading in Expiratory Muscle Strength Training on Orbicularis Oris Muscle Activity

PubMed Central

Yanagisawa, Yukio; Matsuo, Yoshimi; Shuntoh, Hisato; Horiuchi, Noriaki

2014-01-01

[Purpose] The purpose of this study was to elucidate the effect of expiratory resistive loading on orbicularis oris muscle activity. [Subjects] Subjects were 23 healthy individuals (11 males, mean age 25.5±4.3 years; 12 females, mean age 25.0±3.0 years). [Methods] Surface electromyography was performed to measure the activity of the orbicularis oris muscle during maximum lip closure and resistive loading at different expiratory pressures. Measurement was performed at 10%, 30%, 50%, and 100% of maximum expiratory pressure (MEP) for all subjects. The t-test was used to compare muscle activity between maximum lip closure and 100% MEP, and analysis of variance followed by multiple comparisons was used to compare the muscle activities observed at different expiratory pressures. [Results] No significant difference in muscle activity was observed between maximum lip closure and 100% MEP. Analysis of variance with multiple comparisons revealed significant differences among the different expiratory pressures. [Conclusion] Orbicularis oris muscle activity increased with increasing expiratory resistive loading. PMID:24648644

Developing a diagnostic tool for measuring maximum effective temperature within high pressure electrodeless discharges

NASA Astrophysics Data System (ADS)

Whiting, Michael; Preston, Barry; Mucklejohn, Stuart; Santos, Monica; Lister, Graeme

2016-09-01

Here we present an investigation into the feasibility of creating a diagnostic tool for obtaining maximum arc temperature measurements within a high pressure electrodeless discharge; utilizing integrating sphere measurements of optically thin lines emitted from mercury atoms within commercially available high pressure mercury lamp arc tubes. The optically thin lines chosen were 577 nm and 1014 nm from a 250 W high pressure mercury lamp operated at various powers. The effective temperature could be calculated by considering the relative intensities of the two optically thin lines and comparison with the theoretical ratio of the temperature dependent power emitted from the lines derived from the atomic spectral data provided by NIST. The calculations gave effective arc temperatures of 5755, 5804 and 5820 K at 200, 225, 250 W respectively. This method was subsequently used as a basis for determining maximum effective arc temperature within microwave-driven electrodeless discharge capsules, with varying mercury content of 6.07, 9.4 and 12.95 mg within 1 × 10-6 m3 giving maximum effective temperatures of 5163, 4768 and 4715 K respectively at 240 W.

Spark-Timing Control Based on Correlation of Maximum-Economy Spark Timing, Flame-front Travel, and Cylinder-Pressure Rise

NASA Technical Reports Server (NTRS)

Cook, Harvey A; Heinicke, Orville H; Haynie, William H

1947-01-01

An investigation was conducted on a full-scale air-cooled cylinder in order to establish an effective means of maintaining maximum-economy spark timing with varying engine operating conditions. Variable fuel-air-ratio runs were conducted in which relations were determined between the spark travel, and cylinder-pressure rise. An instrument for controlling spark timing was developed that automatically maintained maximum-economy spark timing with varying engine operating conditions. The instrument also indicated the occurrence of preignition.

46 CFR 58.30-25 - Accumulators.

Code of Federal Regulations, 2010 CFR

2010-10-01

... pressure vessel in which energy is stored under high pressure in the form of a gas or a gas and hydraulic... pressures not exceeding the maximum allowable working pressures. When an accumulator forms an integral part...

F-18 high alpha research vehicle surface pressures: Initial in-flight results and correlation with flow visualization and wind-tunnel data

NASA Technical Reports Server (NTRS)

Fisher, David F.; Banks, Daniel W.; Richwine, David M.

1990-01-01

Pressure distributions measured on the forebody and the leading-edge extensions (LEX's) of the NASA F-18 high alpha research vehicle (HARV) were reported at 10 and 50 degree angles of attack and at Mach 0.20 to 0.60. The results were correlated with HARV flow visualization and 6-percent scale F-18 wind-tunnel-model test results. The general trend in the data from the forebody was for the maximum suction pressure peaks to first appear at an angle of attack (alpha) of approximately 19 degrees and increase in magnitude with angle of attack. The LEX pressure distribution general trend was the inward progression and increase in magnitude of the maximum suction peaks up to vortex core breakdown and then the decrease and general flattening of the pressure distribution beyond that. No significant effect of Mach number was noted for the forebody results. However, a substantial compressibility effect on the LEX's resulted in a significant reduction in vortex-induced suction pressure as Mach number increased. The forebody primary and the LEX secondary vortex separation lines, from surface flow visualization, correlated well with the end of pressure recovery, leeward and windward, respectively, of maximum suction pressure peaks. The flight to wind-tunnel correlations were generally good with some exceptions.

Dome of magnetic order inside the nematic phase of sulfur-substituted FeSe under pressure

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

Xiang, Li; Kaluarachchi, Udhara; Bohmer, Anna

2017-07-18

The pressure dependence of the structural, magnetic, and superconducting transitions and of the superconducting upper critical field were studied in sulfur-substituted Fe ( Se 1 - x S x ) . We performed resistance measurements on single crystals with three substitution levels ( x = 0.043 , 0.096, 0.12) under hydrostatic pressures up to 1.8 GPa and in magnetic fields up to 9 T and were compared to data on pure FeSe. Our results illustrate the effects of chemical and physical pressure on Fe ( Se 1 - x S x ). Furthermore, on increasing sulfur content, magnetic order inmore » the low-pressure range is strongly suppressed to a small domelike region in the phase diagrams. But, T s is much less suppressed by sulfur substitution, and T c of Fe ( Se 1 - x S x ) exhibits similar nonmonotonic pressure dependence with a local maximum and a local minimum present in the low-pressure range for all x . The local maximum in T c coincides with the emergence of the magnetic order above T c . At this pressure the slope of the upper critical field decreases abruptly, which may indicate a Fermi-surface reconstruction. The minimum of T c correlates with a broad maximum of the upper critical field slope normalized by T c .« less

Pressure-induced superconductivity in a three-dimensional topological material ZrTe5

PubMed Central

Zhou, Yonghui; Wu, Juefei; Ning, Wei; Li, Nana; Du, Yongping; Chen, Xuliang; Zhang, Ranran; Chi, Zhenhua; Wang, Xuefei; Zhu, Xiangde; Lu, Pengchao; Ji, Cheng; Wan, Xiangang; Yang, Zhaorong; Sun, Jian; Yang, Wenge; Tian, Mingliang; Zhang, Yuheng; Mao, Ho-kwang

2016-01-01

As a new type of topological materials, ZrTe5 shows many exotic properties under extreme conditions. Using resistance and ac magnetic susceptibility measurements under high pressure, while the resistance anomaly near 128 K is completely suppressed at 6.2 GPa, a fully superconducting transition emerges. The superconducting transition temperature Tc increases with applied pressure, and reaches a maximum of 4.0 K at 14.6 GPa, followed by a slight drop but remaining almost constant value up to 68.5 GPa. At pressures above 21.2 GPa, a second superconducting phase with the maximum Tc of about 6.0 K appears and coexists with the original one to the maximum pressure studied in this work. In situ high-pressure synchrotron X-ray diffraction and Raman spectroscopy combined with theoretical calculations indicate the observed two-stage superconducting behavior is correlated to the structural phase transition from ambient Cmcm phase to high-pressure C2/m phase around 6 GPa, and to a mixture of two high-pressure phases of C2/m and P-1 above 20 GPa. The combination of structure, transport measurement, and theoretical calculations enable a complete understanding of the emerging exotic properties in 3D topological materials under extreme environments. PMID:26929327

14 CFR 29.1521 - Powerplant limitations.

Code of Federal Regulations, 2012 CFR

2012-01-01

... pressure (for reciprocating engines); (3) The maximum allowable turbine inlet or turbine outlet gas temperature (for turbine engines); (4) The maximum allowable power or torque for each engine, considering the... maximum allowable turbine inlet or turbine outlet gas temperature (for turbine engines); (5) The maximum...

14 CFR 29.1521 - Powerplant limitations.

Code of Federal Regulations, 2013 CFR

2013-01-01

... pressure (for reciprocating engines); (3) The maximum allowable turbine inlet or turbine outlet gas temperature (for turbine engines); (4) The maximum allowable power or torque for each engine, considering the... maximum allowable turbine inlet or turbine outlet gas temperature (for turbine engines); (5) The maximum...

14 CFR 29.1521 - Powerplant limitations.

Code of Federal Regulations, 2014 CFR

2014-01-01

... pressure (for reciprocating engines); (3) The maximum allowable turbine inlet or turbine outlet gas temperature (for turbine engines); (4) The maximum allowable power or torque for each engine, considering the... maximum allowable turbine inlet or turbine outlet gas temperature (for turbine engines); (5) The maximum...

14 CFR 29.1521 - Powerplant limitations.

Code of Federal Regulations, 2011 CFR

2011-01-01

... pressure (for reciprocating engines); (3) The maximum allowable turbine inlet or turbine outlet gas temperature (for turbine engines); (4) The maximum allowable power or torque for each engine, considering the... maximum allowable turbine inlet or turbine outlet gas temperature (for turbine engines); (5) The maximum...

14 CFR 29.1521 - Powerplant limitations.

Code of Federal Regulations, 2010 CFR

2010-01-01

... pressure (for reciprocating engines); (3) The maximum allowable turbine inlet or turbine outlet gas temperature (for turbine engines); (4) The maximum allowable power or torque for each engine, considering the... maximum allowable turbine inlet or turbine outlet gas temperature (for turbine engines); (5) The maximum...

Thermodynamic analysis of energy density in pressure retarded osmosis: The impact of solution volumes and costs

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

Reimund, Kevin K.; McCutcheon, Jeffrey R.; Wilson, Aaron D.

A general method was developed for estimating the volumetric energy efficiency of pressure retarded osmosis via pressure-volume analysis of a membrane process. The resulting model requires only the osmotic pressure, π, and mass fraction, w, of water in the concentrated and dilute feed solutions to estimate the maximum achievable specific energy density, uu, as a function of operating pressure. The model is independent of any membrane or module properties. This method utilizes equilibrium analysis to specify the volumetric mixing fraction of concentrated and dilute solution as a function of operating pressure, and provides results for the total volumetric energy densitymore » of similar order to more complex models for the mixing of seawater and riverwater. Within the framework of this analysis, the total volumetric energy density is maximized, for an idealized case, when the operating pressure is π/(1+√w⁻¹), which is lower than the maximum power density operating pressure, Δπ/2, derived elsewhere, and is a function of the solute osmotic pressure at a given mass fraction. It was also found that a minimum 1.45 kmol of ideal solute is required to produce 1 kWh of energy while a system operating at “maximum power density operating pressure” requires at least 2.9 kmol. Utilizing this methodology, it is possible to examine the effects of volumetric solution cost, operation of a module at various pressure, and operation of a constant pressure module with various feed.« less

Migration rates and formation injectivity to determine containment time scales of sequestered carbon dioxide

USGS Publications Warehouse

Burke, Lauri

2012-01-01

Additionally, this research establishes a methodology to calculate the injectivity of a target formation. Because injectivity describes the pressure increase due to the introduction of fluids into a formation, the relevant application of injectivity is to determine the pressure increase, due to an injection volume and flow rate, that will induce fractures in the reservoir rocks. This quantity is defined mathematically as the maximum pressure differential between the hydrostatic gradient and the fracture gradient of the target formation. Injectivity is mathematically related to the maximum pressure differential of the formation, and can be used to determine the upper limit for the pressure increase that an injection target can withstand before fracturing.

Conformable pressure vessel for high pressure gas storage

DOEpatents

Simmons, Kevin L.; Johnson, Kenneth I.; Lavender, Curt A.; Newhouse, Norman L.; Yeggy, Brian C.

2016-01-12

A non-cylindrical pressure vessel storage tank is disclosed. The storage tank includes an internal structure. The internal structure is coupled to at least one wall of the storage tank. The internal structure shapes and internally supports the storage tank. The pressure vessel storage tank has a conformability of about 0.8 to about 1.0. The internal structure can be, but is not limited to, a Schwarz-P structure, an egg-crate shaped structure, or carbon fiber ligament structure.

Growth, productivity, and relative extinction risk of a data-sparse devil ray

PubMed Central

Pardo, Sebastián A.; Kindsvater, Holly K.; Cuevas-Zimbrón, Elizabeth; Sosa-Nishizaki, Oscar; Pérez-Jiménez, Juan Carlos; Dulvy, Nicholas K.

2016-01-01

Devil rays (Mobula spp.) face intensifying fishing pressure to meet the ongoing international demand for gill plates. The paucity of information on growth, mortality, and fishing effort for devil rays make quantifying population growth rates and extinction risk challenging. Furthermore, unlike manta rays (Manta spp.), devil rays have not been listed on CITES. Here, we use a published size-at-age dataset for the Spinetail Devil Ray (Mobula japanica), to estimate somatic growth rates, age at maturity, maximum age, and natural and fishing mortality. We then estimate a plausible distribution of the maximum intrinsic population growth rate (rmax) and compare it to 95 other chondrichthyans. We find evidence that larger devil ray species have low somatic growth rate, low annual reproductive output, and low maximum population growth rates, suggesting they have low productivity. Fishing rates of a small-scale artisanal Mexican fishery were comparable to our estimate of rmax, and therefore probably unsustainable. Devil ray rmax is very similar to that of manta rays, indicating devil rays can potentially be driven to local extinction at low levels of fishing mortality and that a similar degree of protection for both groups is warranted. PMID:27658342

On the Origin of a Maximum Peak Pressure on the Target Outside of the Stagnation Point upon Normal Impact of a Blunt Projectile and with Underwater Explosion

NASA Astrophysics Data System (ADS)

Gonor, Alexander; Hooton, Irene

2006-07-01

Impact of a rigid projectile (impactor), against a metal target and a condensed explosive surface considered as the important process accompanying the normal entry of a rigid projectile into a target, was overlooked in the preceding studies. Within the framework of accurate shock wave theory, the flow-field, behind the shock wave attached to the perimeter of the adjoined surface, was defined. An important result is the peak pressure rises at points along the target surface away from the stagnation point. The maximum values of the peak pressure are 2.2 to 3.2 times higher for the metallic and soft targets (nitromethane, PBX 9502), than peak pressure values at the stagnation point. This effect changes the commonly held notion that the maximum peak pressure is reached at the projectile stagnation point. In the present study the interaction of a spherical decaying blast wave, caused by an underwater explosion, with a piece-wise plane target, having corner configurations, is investigated. The numerical calculation results in the determination of the vulnerable spots on the target, where the maximum peak overpressure surpassed that for the head-on shock wave reflection by a factor of 4.

Pneumatic Control Device for the Pershing 2 Adaption Kit

DTIC Science & Technology

1979-03-14

forward force to main- tain a pressure seal (this, versus an-I6-to 25 pound maximum reverse .force component due to pressure). In all probability, initial...stem forward force to main- tain a pressure seal (this, versus an 48-to-25-pound maximum " reverse.force, component due-topressue). In-all probability...PII Li L! Ramn Eniern Inc Contrato . 2960635 GAS GENERATOR COMPATIBILITY U TEST REPORT 1.j Requirement s The requirements for the Pershing II, Phase I

Oxygen Partial Pressure and Oxygen Concentration Flammability: Can They Be Correlated?

NASA Technical Reports Server (NTRS)

Harper, Susana A.; Juarez, Alfredo; Perez, Horacio, III; Hirsch, David B.; Beeson, Harold D.

2016-01-01

NASA possesses a large quantity of flammability data performed in ISS airlock (30% Oxygen 526mmHg) and ISS cabin (24.1% Oxygen 760 mmHg) conditions. As new programs develop, other oxygen and pressure conditions emerge. In an effort to apply existing data, the question arises: Do equivalent oxygen partial pressures perform similarly with respect to flammability? This paper evaluates how material flammability performance is impacted from both the Maximum Oxygen Concentration (MOC) and Maximum Total Pressures (MTP) perspectives. From these studies, oxygen partial pressures can be compared for both the MOC and MTP methods to determine the role of partial pressure in material flammability. This evaluation also assesses the influence of other variables on flammability performance. The findings presented in this paper suggest flammability is more dependent on oxygen concentration than equivalent partial pressure.

Thermodynamic models for bounding pressurant mass requirements of cryogenic tanks

NASA Technical Reports Server (NTRS)

Vandresar, Neil T.; Haberbusch, Mark S.

1994-01-01

Thermodynamic models have been formulated to predict lower and upper bounds for the mass of pressurant gas required to pressurize a cryogenic tank and then expel liquid from the tank. Limiting conditions are based on either thermal equilibrium or zero energy exchange between the pressurant gas and initial tank contents. The models are independent of gravity level and allow specification of autogenous or non-condensible pressurants. Partial liquid fill levels may be specified for initial and final conditions. Model predictions are shown to successfully bound results from limited normal-gravity tests with condensable and non-condensable pressurant gases. Representative maximum collapse factor maps are presented for liquid hydrogen to show the effects of initial and final fill level on the range of pressurant gas requirements. Maximum collapse factors occur for partial expulsions with large final liquid fill fractions.

Effect of infusion pump fill-stroke flow interruption on response to sodium nitroprusside in surgical patients.

PubMed

Mann, H J; Fuhs, D W; Cerra, F B

1988-03-01

The influence of the piston-cassette pump fill stroke on the pharmacodynamic response to sodium nitroprusside was evaluated prospectively in 10 adult patients in the surgical intensive-care unit. Simultaneous analog recordings of blood pressure and fill stroke were made over three complete pump fill cycles in each patient. Sodium nitroprusside flow rates and concentrations were recorded throughout the data-collection period. Analysis was based on the maximum pressure obtained during the two-minute baseline period before a fill stroke (Pmax baseline), the pressure at the initiation of the fill stroke (P initial), and the maximum pressure obtained during the two-minute period after the fill stroke (Pmax postfill). The maximum systolic blood pressure (SBP), diastolic blood pressure (DBP), and mean blood pressure (MBP) during the baseline and post-fill-stroke periods were significantly different. The mean (+/- S.D.) variability in pressure between the time periods Pmax baseline and Pmax postfill was 3.9 +/- 5.8 mm Hg for SBP (range, -8 to +16), 3.5 +/- 5.7 mm Hg for DBP (range, -7 to +13), and 3.6 +/- 5.6 mm Hg for MBP (range, -7 to +14). The likelihood of a pharmacodynamic change was inconsistent both between and within patients. Within patients the difference between cycles for the variability between time periods ranged from a minimum of 2 mm Hg to a maximum of 16 mm Hg for SBP, 2 mm Hg to 17 mm Hg for DBP, and 1 mm Hg to 17 mm Hg for MBP. The variability within the baseline period (Pmax baseline - P initial) in SBP was significantly greater than the variability between the time periods, while the differences for DBP and MBP were not significant.(ABSTRACT TRUNCATED AT 250 WORDS)

Tight swimming trunks to prevent post scrotal surgery: an experimental justification.

PubMed

Al-Abed, Yahya A; Carr, Thomas W

2013-01-01

To conduct a study to measure the pressure effects of the different scrotal supports applied on a simulated expanding scrotal hematoma. We created a model of an expanding hematoma with simultaneous pressure recording using a urodynamics system. Pressures were recorded independently first without application of any support. Then, three types of scrotal supports were tested, including Euron Net Knickers, scrotal suspensory bandage, and tight swimming trunks brand Speedo® brief and shorts. Subsequent pressures were recorded using the model created, which was applied inside the supports worn by two male volunteers A and B. Without any external compression, the pressure inside the simulated expanding hematoma "balloon" reached a maximum of 15 cmH2O. The pressures measured whilst wearing "Netelast knickers" in both subjects A and B reached a maximum of 15 cmH2O suggesting that this garment exerted no measurable compression. The suspensory scrotal support was then tested in both subjects. As the balloon started to fill with saline, the simulated hematoma pushed the scrotal support forward resulting in falling of the balloon outside the scrotal support. Subsequently, Speedo® briefs and shorts were tested. With Speedo® briefs, maximum filling pressures of 49 cmH2O and 40 cmH2O were reached in subjects A and B, respectively. When using Speedo® shorts, however, maximum pressures of 55 cmH2O in subject A and 54 cmH2O in subject B were reached at the end of the balloon filling to 300 mL of saline. The use of tight swimming trunks (Speedo®) has led to satisfactory results in the prevention of hematoma post scrotal surgery.

Air charged and microtip catheters cannot be used interchangeably for urethral pressure measurement: a prospective, single-blind, randomized trial.

PubMed

Zehnder, Pascal; Roth, Beat; Burkhard, Fiona C; Kessler, Thomas M

2008-09-01

We determined and compared urethral pressure measurements using air charged and microtip catheters in a prospective, single-blind, randomized trial. A consecutive series of 64 women referred for urodynamic investigation underwent sequential urethral pressure measurements using an air charged and a microtip catheter in randomized order. Patients were blinded to the type and sequence of catheter used. Agreement between the 2 catheter systems was assessed using the Bland and Altman 95% limits of agreement method. Intraclass correlation coefficients of air charged and microtip catheters for maximum urethral closure pressure at rest were 0.97 and 0.93, and for functional profile length they were 0.9 and 0.78, respectively. Pearson's correlation coefficients and Lin's concordance coefficients of air charged and microtip catheters were r = 0.82 and rho = 0.79 for maximum urethral closure pressure at rest, and r = 0.73 and rho = 0.7 for functional profile length, respectively. When applying the Bland and Altman method, air charged catheters gave higher readings than microtip catheters for maximum urethral closure pressure at rest (mean difference 7.5 cm H(2)O) and functional profile length (mean difference 1.8 mm). There were wide 95% limits of agreement for differences in maximum urethral closure pressure at rest (-24.1 to 39 cm H(2)O) and functional profile length (-7.7 to 11.3 mm). For urethral pressure measurement the air charged catheter is at least as reliable as the microtip catheter and it generally gives higher readings. However, air charged and microtip catheters cannot be used interchangeably for clinical purposes because of insufficient agreement. Hence, clinicians should be aware that air charged and microtip catheters may yield completely different results, and these differences should be acknowledged during clinical decision making.

Maximum Aerodynamic Force on an Ascending Space Vehicle

ERIC Educational Resources Information Center

Backman, Philip

2012-01-01

The March 2010 issue of "The Physics Teacher" includes a great article by Metz and Stinner on the kinematics and dynamics of a space shuttle launch. Within those pages is a brief mention of an event known in the language of the National Aeronautics and Space Administration (NASA) as "maximum dynamic pressure" (called simply "Max.AirPressure" in…

Effect of Training Frequency on Maximum Expiratory Pressure

ERIC Educational Resources Information Center

Anand, Supraja; El-Bashiti, Nour; Sapienza, Christine

2012-01-01

Purpose: To determine the effects of expiratory muscle strength training (EMST) frequency on maximum expiratory pressure (MEP). Method: We assigned 12 healthy participants to 2 groups of training frequency (3 days per week and 5 days per week). They completed a 4-week training program on an EMST trainer (Aspire Products, LLC). MEP was the primary…

40 CFR Table 4 to Subpart Ffff of... - Emission Limits for Storage Tanks

Code of Federal Regulations, 2014 CFR

2014-07-01

... applies to your storage tanks: For each . . . For which . . . Then you must . . . 1. Group 1 storage tank a. The maximum true vapor pressure of total HAP at the storage temperature is ≥76.6 kilopascals i... maximum true vapor pressure of total HAP at the storage temperature is <76.6 kilopascals i. Comply with...

40 CFR Table 4 to Subpart Ffff of... - Emission Limits for Storage Tanks

Code of Federal Regulations, 2013 CFR

2013-07-01

... applies to your storage tanks: For each . . . For which . . . Then you must . . . 1. Group 1 storage tank a. The maximum true vapor pressure of total HAP at the storage temperature is ≥76.6 kilopascals i... maximum true vapor pressure of total HAP at the storage temperature is <76.6 kilopascals i. Comply with...

Generation of a pulsed low-energy electron beam using the channel spark device

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

Elgarhy, M. A. I., E-mail: elgarhy@azhar.edu.eg; Hassaballa, S. E.; Rashed, U. M.

2015-12-15

For the generation of low-energy electron beam, the design and characteristics of channel spark discharge (CSD) operating at a low voltage are presented in this paper. The discharge voltage, discharge current, X-ray emissions, and electron beam current were experimentally determined. The effects of the applied voltage, working gas pressure, and external capacitance on the CSD and beam parameters were measured. At an applied voltage of 11 kV, an oxygen gas pressure of 25 mTorr, and an external capacitance of 16.45 nF, the maximum measured current was 900 A. The discharge current increased with the increase in the pressure and capacitance,more » while its periodic time decreased with the increase in the pressure. Two types of the discharge were identified and recorded: the hollow cathode discharge and the conduction discharge. A Faraday cup was used to measure the beam current. The maximum measured beam current was 120 A, and the beam signal exhibited two peaks. The increase in both the external capacitance and the applied discharge voltage increased the maximum electron beam current. The electron-beam pulse time decreased with the increase in the gas pressure at a constant voltage and increased with the decrease in the applied discharge voltage. At an applied voltage of 11 kV and an oxygen gas pressure of 15 mTorr, the maximum beam energy was 2.8 keV. The X-ray signal intensity decreased with the increase in the gas pressure and increased with the increase in the capacitance.« less

Firefighter's compressed air breathing system pressure vessel development program

NASA Technical Reports Server (NTRS)

Beck, E. J.

1974-01-01

The research to design, fabricate, test, and deliver a pressure vessel for the main component in an improved high-performance firefighter's breathing system is reported. The principal physical and performance characteristics of the vessel which were required are: (1) maximum weight of 9.0 lb; (2) maximum operating pressure of 4500 psig (charge pressure of 4000 psig); (3) minimum contained volume of 280 in. 3; (4) proof pressure of 6750 psig; (5) minimum burst pressure of 9000 psig following operational and service life; and (6) a minimum service life of 15 years. The vessel developed to fulfill the requirements described was completely sucessful, i.e., every category of performence was satisfied. The average weight of the vessel was found to be about 8.3 lb, well below the 9.0 lb specification requirement.

IN VITRO COMPARISON OF MAXIMUM PRESSURE DEVELOPED BY IRRIGATION SYSTEMS IN A KIDNEY MODEL.

PubMed

Proietti, Silvia; Dragos, Laurian; Somani, Bhaskar K; Butticè, Salvatore; Talso, Michele; Emiliani, Esteban; Baghdadi, Mohammed; Giusti, Guido; Traxer, Olivier

2017-04-05

To evaluate in vitro the maximum pressure generated in an artificial kidney model when people of different levels of strengths used various irrigation systems. Fifteen people were enrolled and divided in 3 groups based on their strengths. Individual strength was evaluated according to the maximum pressure each participant was able to achieve using an Encore™ Inflator. The irrigation systems evaluated were: T-FlowTM Dual Port, HilineTM, continuous flow single action pumping system (SAPSTM) with the system close and open, Irri-flo IITM, a simple 60-ml syringe and PeditrolTM . Each irrigation system was connected to URF-V2 ureteroscope, which was inserted into an artificial kidney model. Each participant was asked to produce the maximum pressure possible with every irrigation device. Pressure was measured with the working channel (WC) empty, with a laser fiber and a basket inside. The highest pressure was achieved with the 60 ml-syringe system and the lowest with SAPS continuous version system (with continuous irrigation open), compared to the other irrigation devices (p< 0.0001). Irrespective of the irrigation system, there was a significant difference in the pressure between the WC empty and when occupied with the laser fiber or the basket inside it (p<0.0001). The stratification between the groups showed that the most powerful group could produce the highest pressure in the kidney model with all the irrigation devices in almost any situation. The exception to this was the T-Flow system, which was the only device where no statistical differences were detected among these groups. The use of irrigation systems can often generate excessive pressure in an artificial kidney model, especially with an unoccupied WC of the ureteroscope. Depending on the strength of force applied, very high pressure can be generated by most irrigation devices irrespective of whether the scope is occupied or not.

Acoustic cooling engine

DOEpatents

Hofler, Thomas J.; Wheatley, John C.; Swift, Gregory W.; Migliori, Albert

1988-01-01

An acoustic cooling engine with improved thermal performance and reduced internal losses comprises a compressible fluid contained in a resonant pressure vessel. The fluid has a substantial thermal expansion coefficient and is capable of supporting an acoustic standing wave. A thermodynamic element has first and second ends and is located in the resonant pressure vessel in thermal communication with the fluid. The thermal response of the thermodynamic element to the acoustic standing wave pumps heat from the second end to the first end. The thermodynamic element permits substantial flow of the fluid through the thermodynamic element. An acoustic driver cyclically drives the fluid with an acoustic standing wave. The driver is at a location of maximum acoustic impedance in the resonant pressure vessel and proximate the first end of the thermodynamic element. A hot heat exchanger is adjacent to and in thermal communication with the first end of the thermodynamic element. The hot heat exchanger conducts heat from the first end to portions of the resonant pressure vessel proximate the hot heat exchanger. The hot heat exchanger permits substantial flow of the fluid through the hot heat exchanger. The resonant pressure vessel can include a housing less than one quarter wavelength in length coupled to a reservoir. The housing can include a reduced diameter portion communicating with the reservoir. The frequency of the acoustic driver can be continuously controlled so as to maintain resonance.

Comparison between SAGE II and ISCCP high-level clouds. 2: Locating clouds tops

NASA Technical Reports Server (NTRS)

Liao, Xiaohan; Rossow, William B.; Rind, David

1995-01-01

A comparison is made of the vertical distribution of high-level cloud tops derived from the Stratospheric Aerosol and Gas Experiment II (SAGE II) occultation measurements and from the International Satellite Cloud Climatology Project (ISCCP) for all Julys and Januarys in 1985 to 1990. The results suggest that ISCCP overestimates the pressure of high-level clouds by up to 50-150 mbar, particularly at low latitudes. This is caused by the frequent presence of clouds with diffuse tops (greater than 50% time when cloudy events are observed). The averaged vertical extent of the diffuse top is about 1.5 km. At midlatitudes where the SAGE II and ISCCP cloud top pressure agree best, clouds with distinct tops reach a maximum relative proportion of the total level cloud amount (about 30-40%), and diffuse-topped clouds are reduced to their minimum (30-40%). The ISCCP-defined cloud top pressure should be regarded not as the material physical height of the clouds but as the level which emits the same infrared radiance as observed. SAGE II and ISCCP cloud top pressures agree for clouds with distinct tops. There is also an indication that the cloud top pressures of optically thin clouds not overlying thicker clouds are poorly estimated by ISCCP at middle latitudes. The average vertical extent of these thin clouds is about 2.5 km.

Parametric investigation of single-expansion-ramp nozzles at Mach numbers from 0.60 to 1.20

NASA Technical Reports Server (NTRS)

Capone, Francis J.; Re, Richard J.; Bare, E. Ann

1992-01-01

An investigation was conducted in the Langley 16-Foot Transonic Tunnel to determine the effects of varying six nozzle geometric parameters on the internal and aeropropulsive performance characteristics of single-expansion-ramp nozzles. This investigation was conducted at Mach numbers from 0.60 to 1.20, nozzle pressure ratios from 1.5 to 12, and angles of attack of 0 deg +/- 6 deg. Maximum aeropropulsive performance at a particular Mach number was highly dependent on the operating nozzle pressure ratio. For example, as the nozzle upper ramp length or angle increased, some nozzles had higher performance at a Mach number of 0.90 because of the nozzle design pressure was the same as the operating pressure ratio. Thus, selection of the various nozzle geometric parameters should be based on the mission requirements of the aircraft. A combination of large upper ramp and large lower flap boattail angles produced greater nozzle drag coefficients at Mach number greater than 0.80, primarily from shock-induced separation on the lower flap of the nozzle. A static conditions, the convergent nozzle had high and nearly constant values of resultant thrust ratio over the entire range of nozzle pressure ratios tested. However, these nozzles had much lower aeropropulsive performance than the convergent-divergent nozzle at Mach number greater than 0.60.

Relationships amongst body dissatisfaction, internalisation of the media body ideal and perceived pressure from media in adolescent girls and boys.

PubMed

Knauss, Christine; Paxton, Susan J; Alsaker, Françoise D

2007-12-01

Sociocultural factors that underpin gender differences in body dissatisfaction have not frequently been explored. We examined the relative contribution of internalization of media body ideals and perceived pressure to achieve this ideal in explaining body dissatisfaction in adolescent boys and girls. A sample of 819 boys and 791 girls completed measures of internalization of body ideals, perceived pressure, body mass index (BMI) and body dissatisfaction. As expected, girls showed higher body dissatisfaction, internalization and pressure than boys. Internalization, pressure and BMI contributed to the prediction of body dissatisfaction in boys and in girls although these variables explained less variance in body dissatisfaction in boys. In addition, for girls the strongest predictor of body dissatisfaction was internalization, whilst for boys the strongest predictor was pressure. Differences in extent of internalization and pressure may contribute to higher body dissatisfaction in girls than boys. These sociocultural factors may affect girls and boys differently.

Energy harvesting via thermo-piezoelectric transduction within a heated capillary

NASA Astrophysics Data System (ADS)

Monroe, J. G.; Bhandari, M.; Fairley, J.; Myers, O. J.; Shamsaei, N.; Thompson, S. M.

2017-07-01

Thermal-to-kinetic-to-electrical energy conversion is demonstrated through the use of a piezoelectric transducer (PZT) integrated within a section of an oscillating heat pipe (OHP) partially filled with water. The sealed PZT transducer was configured as a bow spring parallel to the dominant flow direction within the OHP. The bottom portion of the OHP was heated in increments of 50 W, while its top portion was actively cooled via water blocks. At ˜50 W, the internal fluid started to oscillate at ˜2-4 Hz due to the non-uniform vapor pressure generated in the OHP evaporator. Low-frequency fluid "pulses" were observed to occur across the flexed, in-line piezoelectric transducer, resulting in its deflection and measureable voltage spikes ranging between 24 and 63 mV. The OHP, while having its internal fluid enthalpy harvested, was found to still have an ultra-high thermal conductivity on-the-order of 10 kW/m K; however, its maximum operating heat load decreased due to the pressure drop introduced by the PZT material. The thermo-piezoelectric harvesting concept made possible via the thermally driven fluid oscillations within an OHP provides a passive method for combined energy harvesting and thermal management that is both scalable and portable.

Effect of initial moisture content on the in-vessel composting under air pressure of organic fraction of municipal solid waste in Morocco.

PubMed

Makan, Abdelhadi; Assobhei, Omar; Mountadar, Mohammed

2013-01-03

This study aimed to evaluate the effect of initial moisture content on the in-vessel composting under air pressure of organic fraction of municipal solid waste in Morocco in terms of internal temperature, produced gases quantity, organic matter conversion rate, and the quality of the final composts.For this purpose, in-vessel bioreactor was designed and used to evaluate both appropriate initial air pressure and appropriate initial moisture content for the composting process. Moreover, 5 experiments were carried out within initial moisture content of 55%, 65%, 70%, 75% and 85%. The initial air pressure and the initial moisture content of the mixture showed a significant effect on the aerobic composting. The experimental results demonstrated that for composting organic waste, relatively high moisture contents are better at achieving higher temperatures and retaining them for longer times.This study suggested that an initial moisture content of around 75%, under 0.6 bar, can be considered as being suitable for efficient composting of organic fraction of municipal solid waste. These last conditions, allowed maximum value of temperature and final composting product with good physicochemical properties as well as higher organic matter degradation and higher gas production. Moreover, final compost obtained showed good maturity levels and can be used for agricultural applications.

Energy balance and assessment of the pressure build-up around a bolt fastener due to sparking during a lightning impact

NASA Astrophysics Data System (ADS)

Teulet, Philippe; Billoux, Tommy; Cressault, Yann; Masquère, Mathieu; Gleizes, Alain; Revel, Ivan; Lepetit, Bruno; Peres, Gilles

2017-03-01

This work is devoted to the calculation of the energy balance associated with the formation of an electric arc between the bolt shank and an inner structural part of the fuselage during a lightning strike. Assessment of the pressure build-up in the confined volume around the bolt fastener has also been performed. This pressure rise comes from the temperature increase and from the mass density increase (melting and vaporisation of materials). Previous electrical measurements performed by Airbus Group during a lightning test campaign have been used to calculate the total available electrical energy. The energies necessary for melting and vaporisation of bolt and rib are derived from thermodynamic properties of aluminium and titanium. A numerical code has been developed to determine the chemical composition (under the local thermodynamic equilibrium [LTE] assumption) and the internal energy of the plasma for air-Al/Ti mixtures. Plasma and material radiation losses and heat conduction losses have also been evaluated. Finally, an analytical model has been implemented to determine the overpressure as a function of the deposited electrical energy, the energy involved in the arc formation, the energy necessary for melting and the plasma composition and mass density. With this approach, maximum pressure values are in the range 200-330 bars.

Maximum magnitude estimations of induced earthquakes at Paradox Valley, Colorado, from cumulative injection volume and geometry of seismicity clusters

NASA Astrophysics Data System (ADS)

Yeck, William L.; Block, Lisa V.; Wood, Christopher K.; King, Vanessa M.

2015-01-01

The Paradox Valley Unit (PVU), a salinity control project in southwest Colorado, disposes of brine in a single deep injection well. Since the initiation of injection at the PVU in 1991, earthquakes have been repeatedly induced. PVU closely monitors all seismicity in the Paradox Valley region with a dense surface seismic network. A key factor for understanding the seismic hazard from PVU injection is the maximum magnitude earthquake that can be induced. The estimate of maximum magnitude of induced earthquakes is difficult to constrain as, unlike naturally occurring earthquakes, the maximum magnitude of induced earthquakes changes over time and is affected by injection parameters. We investigate temporal variations in maximum magnitudes of induced earthquakes at the PVU using two methods. First, we consider the relationship between the total cumulative injected volume and the history of observed largest earthquakes at the PVU. Second, we explore the relationship between maximum magnitude and the geometry of individual seismicity clusters. Under the assumptions that: (i) elevated pore pressures must be distributed over an entire fault surface to initiate rupture and (ii) the location of induced events delineates volumes of sufficiently high pore-pressure to induce rupture, we calculate the largest allowable vertical penny-shaped faults, and investigate the potential earthquake magnitudes represented by their rupture. Results from both the injection volume and geometrical methods suggest that the PVU has the potential to induce events up to roughly MW 5 in the region directly surrounding the well; however, the largest observed earthquake to date has been about a magnitude unit smaller than this predicted maximum. In the seismicity cluster surrounding the injection well, the maximum potential earthquake size estimated by these methods and the observed maximum magnitudes have remained steady since the mid-2000s. These observations suggest that either these methods overpredict maximum magnitude for this area or that long time delays are required for sufficient pore-pressure diffusion to occur to cause rupture along an entire fault segment. We note that earthquake clusters can initiate and grow rapidly over the course of 1 or 2 yr, thus making it difficult to predict maximum earthquake magnitudes far into the future. The abrupt onset of seismicity with injection indicates that pore-pressure increases near the well have been sufficient to trigger earthquakes under pre-existing tectonic stresses. However, we do not observe remote triggering from large teleseismic earthquakes, which suggests that the stress perturbations generated from those events are too small to trigger rupture, even with the increased pore pressures.

Long-term therapeutic efficacy of photo-selective vaporization of prostate

NASA Astrophysics Data System (ADS)

Arum, Carl-Jørgen; Muller, Camilla; Romundstad, Pal; Stokkan, Inger; Mjønes, Jan

2010-02-01

OBJECTIVES: We evaluated the long term therapeutic efficacy of 80 watt photo-selective vaporization of the prostate (PVP) in patients suffering from lower urinary tract symptoms (LUTS) secondary to prostatic obstruction. MATERIAL & METHODS: 150 unselected patients at the average age 73 (range 51-92) and a mean American Society of Anesthesiologists score of 2.4 (median 2.0), of whom 33% were medicated with acetylsalicylic acid and 5% were anticoagulated with warfarin. Inclusion/exclusion criteria were the same as for TUR-P at our institution. First patient was operated March 2004 and yearly follow-up of all patients has been attempted for 5 years. Follow-up variables have included yearly creatinine, PSA, IPSS, ØOL, post-void residual urin and maximum/average urine flow rate. RESULTS: At 12 and 24 months postoperatively, the following parameters were significantly (p<0.001) improved: trans-rectal ultrasound, international prostate symptom score, quality of life score, post-void residual urine volume, flow max/average, opening pressure, pressure @ flow-max, and micturition resistance. At 48 and 60 months creatinine, PSA, IPSS, ØOL, post-void residual urin and maximum/average urine flow rates were still significantly (p<0.001) improved compared to pre-operative values. CONCLUSION: Up to 5 year follow-up reveals that 80 watt PVP provides significant and stable symptom relief as well as objective improvement in residual urine and flowmetric outcomes.

First-principles equation-of-state table of beryllium based on density-functional theory calculations

DOE PAGES

Ding, Y. H.; Hu, S. X.

2017-06-06

Beryllium has been considered a superior ablator material for inertial confinement fusion (ICF) target designs. An accurate equation-of-state (EOS) of beryllium under extreme conditions is essential for reliable ICF designs. Based on density-functional theory (DFT) calculations, we have established a wide-range beryllium EOS table of density ρ = 0.001 to 500 g/cm 3 and temperature T = 2000 to 10 8 K. Our first-principle equation-of-state (FPEOS) table is in better agreement with the widely used SESAME EOS table (SESAME 2023) than the average-atom INFERNO and Purgatorio models. For the principal Hugoniot, our FPEOS prediction shows ~10% stiffer than the lastmore » two models in the maximum compression. Although the existing experimental data (only up to 17 Mbar) cannot distinguish these EOS models, we anticipate that high-pressure experiments at the maximum compression region should differentiate our FPEOS from INFERNO and Purgatorio models. Comparisons between FPEOS and SESAME EOS for off-Hugoniot conditions show that the differences in the pressure and internal energy are within ~20%. By implementing the FPEOS table into the 1-D radiation–hydrodynamic code LILAC, we studied in this paper the EOS effects on beryllium-shell–target implosions. Finally, the FPEOS simulation predicts higher neutron yield (~15%) compared to the simulation using the SESAME 2023 EOS table.« less

First-principles equation-of-state table of beryllium based on density-functional theory calculations

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

Ding, Y. H.; Hu, S. X.

Beryllium has been considered a superior ablator material for inertial confinement fusion (ICF) target designs. An accurate equation-of-state (EOS) of beryllium under extreme conditions is essential for reliable ICF designs. Based on density-functional theory (DFT) calculations, we have established a wide-range beryllium EOS table of density ρ = 0.001 to 500 g/cm 3 and temperature T = 2000 to 10 8 K. Our first-principle equation-of-state (FPEOS) table is in better agreement with the widely used SESAME EOS table (SESAME 2023) than the average-atom INFERNO and Purgatorio models. For the principal Hugoniot, our FPEOS prediction shows ~10% stiffer than the lastmore » two models in the maximum compression. Although the existing experimental data (only up to 17 Mbar) cannot distinguish these EOS models, we anticipate that high-pressure experiments at the maximum compression region should differentiate our FPEOS from INFERNO and Purgatorio models. Comparisons between FPEOS and SESAME EOS for off-Hugoniot conditions show that the differences in the pressure and internal energy are within ~20%. By implementing the FPEOS table into the 1-D radiation–hydrodynamic code LILAC, we studied in this paper the EOS effects on beryllium-shell–target implosions. Finally, the FPEOS simulation predicts higher neutron yield (~15%) compared to the simulation using the SESAME 2023 EOS table.« less

Precise predictions of H2O line shapes over a wide pressure range using simulations corrected by a single measurement

NASA Astrophysics Data System (ADS)

Ngo, N. H.; Nguyen, H. T.; Tran, H.

2018-03-01

In this work, we show that precise predictions of the shapes of H2O rovibrational lines broadened by N2, over a wide pressure range, can be made using simulations corrected by a single measurement. For that, we use the partially-correlated speed-dependent Keilson-Storer (pcsdKS) model whose parameters are deduced from molecular dynamics simulations and semi-classical calculations. This model takes into account the collision-induced velocity-changes effects, the speed dependences of the collisional line width and shift as well as the correlation between velocity and internal-state changes. For each considered transition, the model is corrected by using a parameter deduced from its broadening coefficient measured for a single pressure. The corrected-pcsdKS model is then used to simulate spectra for a wide pressure range. Direct comparisons of the corrected-pcsdKS calculated and measured spectra of 5 rovibrational lines of H2O for various pressures, from 0.1 to 1.2 atm, show very good agreements. Their maximum differences are in most cases well below 1%, much smaller than residuals obtained when fitting the measurements with the Voigt line shape. This shows that the present procedure can be used to predict H2O line shapes for various pressure conditions and thus the simulated spectra can be used to deduce the refined line-shape parameters to complete spectroscopic databases, in the absence of relevant experimental values.

Increase of lower esophageal sphincter pressure after osteopathic intervention on the diaphragm in patients with gastroesophageal reflux.

PubMed

da Silva, R C V; de Sá, C C; Pascual-Vaca, Á O; de Souza Fontes, L H; Herbella Fernandes, F A M; Dib, R A; Blanco, C R; Queiroz, R A; Navarro-Rodriguez, T

2013-07-01

The treatment of gastroesophageal reflux disease may be clinical or surgical. The clinical consists basically of the use of drugs; however, there are new techniques to complement this treatment, osteopathic intervention in the diaphragmatic muscle is one these. The objective of the study is to compare pressure values in the examination of esophageal manometry of the lower esophageal sphincter (LES) before and immediately after osteopathic intervention in the diaphragm muscle. Thirty-eight patients with gastroesophageal reflux disease - 16 submitted to sham technique and 22 submitted osteopathic technique - were randomly selected. The average respiratory pressure (ARP) and the maximum expiratory pressure (MEP) of the LES were measured by manometry before and after osteopathic technique at the point of highest pressure. Statistical analysis was performed using the Student's t-test and Mann-Whitney, and magnitude of the technique proposed was measured using the Cohen's index. Statistically significant difference in the osteopathic technique was found in three out of four in relation to the group of patients who performed the sham technique for the following measures of LES pressure: ARP with P= 0.027. The MEP had no statistical difference (P= 0.146). The values of Cohen d for the same measures were: ARP with d= 0.80 and MEP d= 0.52. Osteopathic manipulative technique produces a positive increment in the LES region soon after its performance. © 2012 Copyright the Authors. Journal compilation © 2012, Wiley Periodicals, Inc. and the International Society for Diseases of the Esophagus.

90-kilobar diamond-anvil high-pressure cell for use on an automatic diffractometer.

PubMed

Schiferl, D; Jamieson, J C; Lenko, J E

1978-03-01

A gasketed diamond-anvil high-pressure cell is described which can be used on a four-circle automatic diffractometer to collect x-ray intensity data from single-crystal samples subjected to truly hydrostatic pressures of over 90 kilobars. The force generating system exerts only forces normal to the diamond faces to obtain maximum reliability. A unique design allows exceptionally large open areas for maximum x-ray access and is particularly well suited for highly absorbing materials, as the x rays are not transmitted through the sample. Studies on ruby show that high-pressure crystal structure determinations may be done rapidly, reliably, and routinely with this system.

Methods and apparatus for moving and separating materials exhibiting different physical properties

DOEpatents

Peterson, Stephen C.; Brimhall, Owen D.; McLaughlin, Thomas J.; Baker, Charles D.; Sparks, Sam L.

1991-01-01

Methods and apparatus for controlling the movement of materials having different physical properties when one of the materials is a fluid. The invention does not rely on flocculation, sedimentation, centrifugation, the buoyancy of the materials, or any other gravity dependent characteristic, in order to achieve its desired results. The methods of the present invention provide that a first acoustic wave is propagated through a vessel containing the materials. A second acoustic wave, at a frequency different than the first acoustic wave, is also propagated through the vessel so that the two acoustic waves are superimposed upon each other. The superimposition of the two waves creates a beat frequency wave. The beat frequency wave comprises pressure gradients dividing regions of maximum and minimum pressure. The pressure gradients and the regions of maximum and minimum pressure move through space and time at a group velocity. The moving pressure gradients and regions of maximum and minimum pressure act upon the materials so as to move one of the materials towards a predetermined location in the vessel. The present invention provides that the materials may be controllably moved toward a location, aggregated at a particular location, or physically separated from each other.

Methods and apparatus for moving and separating materials exhibiting different physical properties

DOEpatents

Peterson, Stephen C.; Brimhall, Owen D.; McLaughlin, Thomas J.; Baker, Charles D.; Sparks, Sam L.

1988-01-01

Methods and apparatus for controlling the movement of materials having different physical properties when one of the materials is a fluid. The invention does not rely on flocculation, sedimentation, centrifugation, the buoyancy of the materials, or any other gravity dependent characteristic, in order to achieve its desired results. The methods of the present invention provide that a first acoustic wave is progpagated through a vessel containing the materials. A second acoustic wave, at a frequency different than the first acoustic wave, is also propagated through the vessel so that the two acoustic waves are superimposed upon each other. The superimposition of the two waves creates a beat frequency wave. The beat frequency wave comprises pressure gradients dividing regions of maximum and minimum pressure. The pressure gradients and the regions of maximum and minimum pressure move through space and time at a group velocity. The moving pressure gradients and regions of maximum and minimum pressure act upon the marterials so as to move one of the materials towards a predetermined location in the vessel. The present invention provides that the materials may be controllably moved toward a location, aggreated at a particular location, or physically separated from each other.

Surface electromyography activity of the rectus abdominis, internal oblique, and external oblique muscles during forced expiration in healthy adults.

PubMed

Ito, Kenichi; Nonaka, Koji; Ogaya, Shinya; Ogi, Atsushi; Matsunaka, Chiaki; Horie, Jun

2016-06-01

We aimed to characterize rectus abdominis, internal oblique, and external oblique muscle activity in healthy adults under expiratory resistance using surface electromyography. We randomly assigned 42 healthy adult subjects to 3 groups: 30%, 20%, and 10% maximal expiratory intraoral pressure (PEmax). After measuring 100% PEmax and muscle activity during 100% PEmax, the activity and maximum voluntary contraction of each muscle during the assigned experimental condition were measured. At 100% PEmax, the external oblique (p<0.01) and internal oblique (p<0.01) showed significantly elevated activity compared with the rectus abdominis muscle. Furthermore, at 20% and 30% PEmax, the external oblique (p<0.05 and<0.01, respectively) and the internal oblique (p<0.05 and<0.01, respectively) showed significantly elevated activity compared with the rectus abdominis muscle. At 10% PEmax, no significant differences were observed in muscle activity. Although we observed no significant difference between 10% and 20% PEmax, activity during 30% PEmax was significantly greater than during 20% PEmax (external oblique: p<0.05; internal oblique: p<0.01). The abdominal oblique muscles are the most active during forced expiration. Moreover, 30% PEmax is the minimum intensity required to achieve significant, albeit very slight, muscle activity during expiratory resistance. Copyright © 2016 Elsevier Ltd. All rights reserved.

Aeroacoustic Characteristics of a Rectangular Multi-Element Supersonic Jet Mixer-Ejector Nozzle

NASA Technical Reports Server (NTRS)

Raman, Ganesh; Taghavi, Ray

1996-01-01

This paper provides a unique, detailed evaluation of the acoustics and aerodynamics of a rectangular multi-element supersonic jet mixer-ejector noise suppressor. The performance of such mixer-ejectors is important in aircraft engine application for noise suppression and thrust augmentation. In contrast to most prior experimental studies on ejectors that reported either aerodynamic or acoustic data, our work documents both types of data. We present information on the mixing, pumping, ejector wall pressure distribution, thrust augmentation and noise suppression characteristics of four simple, multi-element, jet mixer-ejector configurations. The four configurations included the effect of ejector area ratio (AR = ejector area/primary jet area) and the effect of non-parallel ejector walls. We also studied in detail the configuration that produced the best noise suppression characteristics. Our results show that ejector configurations that produced the maximum maximum pumping (entrained flow per secondary inlet area) also exhibited the lowest wall pressures in the inlet region, and the maximum thrust augmentation. When cases having the same total mass flow were compared, we found that noise suppression trends corresponded with those for pumping. Surprisingly, the mixing (quantified by the peak Mach number, and flow uniformity) at the ejector exit exhibited no relationship to the noise suppression at moderate primary jet fully expanded Mach numbers (Mj is less than 1.4). However, the noise suppression dependence on the mixing was apparent at higher Mj. The above observations are justified by noting that the mixing at the ejector exit is ot a strong factor in determining the radiated noise when noise produced internal to the ejector dominates the noise field outside the ejector.

Simultaneous in vivo comparison of water-filled and air-filled pressure measurement catheters: Implications for good urodynamic practice.

PubMed

Gammie, A; Abrams, P; Bevan, W; Ellis-Jones, J; Gray, J; Hassine, A; Williams, J; Hashim, H

2016-11-01

This study aimed to evaluate whether the pressure readings obtained from air-filled catheters (AFCs) are the same as the readings from simultaneously inserted water-filled catheters (WFCs). It also aimed to make any possible recommendations for the use of AFCs to conform to International Continence Society (ICS) Good Urodynamic Practices (GUP). Female patients undergoing urodynamic studies in a single center had water-filled and air-filled catheters simultaneously measuring abdominal and intravesical pressure during filling with saline and during voiding. The pressures recorded by each system at each event during the test were compared using paired t-test and Bland-Altman analyses. 62 patients were recruited, of whom 51 had pressures that could be compared during filling, and 23 during voiding. On average, the pressures measured by the two systems were not significantly different during filling and at maximum flow, but the values for a given patient were found to differ by up to 10 cmH 2 O. This study shows that AFCs and WFCs cannot be assumed to register equal values of pressure. It has further shown that even when the p det readings are compared with their value at the start of a test, a divergence of values of up to 10 cmH 2 O remains. If AFCs are used, care must be taken to compensate for any p det variations that occur during patient movement. Before AFCs are adopted, new normal values for resting pressures need to be developed to allow good quality AFC pressure readings to be made. Neurourol. Urodynam. 35:926-933, 2016. © 2015 Wiley Periodicals, Inc. © 2015 Wiley Periodicals, Inc.

Age-Related Variability in Tongue Pressure Patterns for Maximum Isometric and Saliva Swallowing Tasks

PubMed Central

Peladeau-Pigeon, Melanie

2017-01-01

Purpose The ability to generate tongue pressure plays a major role in bolus transport in swallowing. In studies of motor control, stability or variability of movement is a feature that changes with age, disease, task complexity, and perturbation. In this study, we explored whether age and tongue strength influence the stability of the tongue pressure generation pattern during isometric and swallowing tasks in healthy volunteers. Method Tongue pressure data, collected using the Iowa Oral Performance Instrument, were analyzed from 84 participants in sex-balanced and decade age-group strata. Tasks included maximum anterior and posterior isometric pressures and regular-effort saliva swallows. The cyclic spatiotemporal index (cSTI) was used to capture stability (vs. variability) in patterns of pressure generation. Mixed-model repeated measures analyses of covariance were performed separately for each task (anterior and posterior isometric pressures, saliva swallows) with between-participant factors of age group and sex, a within-participant factor of task repetition, and a continuous covariate of tongue strength. Results Neither age group nor sex effects were found. There was no significant relationship between tongue strength and the cSTI on the anterior isometric tongue pressure task (r = −.11). For the posterior isometric tongue pressure task, a significant negative correlation (r = −.395) was found between tongue strength and the cSTI. The opposite pattern of a significant positive correlation (r = .29) between tongue strength and the cSTI was seen for the saliva swallow task. Conclusions Tongue pressure generation patterns appear highly stable across repeated maximum isometric and saliva swallow tasks, despite advancing age. Greater pattern variability is seen with weaker posterior isometric pressures. Overall, saliva swallows had the lowest pressure amplitudes and highest pressure pattern variability as measured by the cSTI. PMID:29114767

Effect of partial meniscectomy at the medial posterior horn on tibiofemoral contact mechanics and meniscal hoop strains in human knees.

PubMed

Seitz, Andreas Martin; Lubomierski, Anja; Friemert, Benedikt; Ignatius, Anita; Dürselen, Lutz

2012-06-01

We examined the influence of partial meniscectomy of 10 mm width on 10 human cadaveric knee joints, as it is performed during the treatment of radial tears in the posterior horn of the medial meniscus, on maximum contact pressure, contact area (CA), and meniscal hoop strain in the lateral and medial knee compartments. In case of 0° and 30° flexion angle, 20% and 50% partial meniscectomy did not influence maximum contact pressure and area. Only in case of 60° knee flexion, 50% partial resection increased medial maximum contact pressure and decreased the medial CA statistically significant. However, 100% partial resection increased maximum contact pressure and decreased CA significantly in the meniscectomized medial knee compartment in all tested knee positions. No significant differences were noted for meniscal hoop strain. From a biomechanical point of view, our in vitro study suggests that the medial joint compartment is not in danger of accelerated cartilage degeneration up to a resection limit of 20% meniscal depth and 10 mm width. Contact mechanics are likely to be more sensitive to partial meniscectomy at higher flexion angles, which has to be further investigated. Copyright © 2011 Orthopaedic Research Society.

High-pressure Infrared Spectra of Tal and Lawsonite

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

Scott,H.; Liu, Z.; Hemley, R.

2007-01-01

We present high-pressure infrared spectra of two geologically important hydrous minerals: talc, Mg3Si4O10(OH)2 and lawsonite, CaAl2Si2O7(OH)2{center_dot}H2O,{center_dot}at room temperature. For lawsonite, our data span the far infrared region from 150 to 550 cm-1 and extend to 25 GPa. We combine our new spectroscopic data with previously published high-pressure mid-infrared and Raman data to constrain the Gr{umlt u}neisen parameter and vibrational density of states under pressure. In the case of talc, we present high-pressure infrared data that span both the mid and far infrared from 150 to 3800 cm-1 covering lattice, silicate, and hydroxyl stretching vibrations to a maximum pressure of 30more » GPa. Both phases show remarkable metastability well beyond their nominal maximum thermodynamic stability at simultaneous high-pressure and high-temperature conditions.« less

Cure-in-place process for seals

DOEpatents

Hirasuna, Alan R.

1981-01-01

A cure-in-place process which allows a rubber seal element to be deformed to its service configuration before it is cross-linked and, hence, is a plastic and does not build up internal stress as a result of the deformation. This provides maximum residual strength to resist the differential pressure. Furthermore, the process allows use of high modulus formulations of the rubber seal element which would otherwise crack if cured and then deformed to its service configuration, resulting in a seal which has better gap bridging capability. Basically, the process involves positioning an uncured seal element in place, deforming it to its service configuration, heating the seal element, curing it in place, and then fully seating the seal.

Central Heat Plant Modernization: FY98 Update and Recommendations.

DTIC Science & Technology

1999-12-01

Boiler and Pressure Vessel Code suggests an inspection frequency of 12 months for...28 April 1997). ASME International, Boiler and Pressure Vessel Code (ASME International, New York, NY, 1995). Bloomquist, R.G., J.D. Nimmons, and K...Services (HQDA, 28 April 1997). ASME International, Boiler and Pressure Vessel Code (ASME International, New York, NY, 1995). Bloomquist, R.G.,

Effects of intravesical hydrostatic pressure and volume on the distensibility of the canine prostatic portion of the urethra.

PubMed

Johnston, G R; Feeney, D A; Osborne, C A; Johnston, S D; Smith, F O; Jessen, C R

1985-03-01

Positive-contrast retrograde urethrocystograms were obtained serially on 12 male dogs weighing 11.4 to 23.2 kg before, during, and after the injection of contrast medium until the urinary bladder neck and prostatic and membranous portions of the urethra remained open and distended as viewed by fluoroscopy. Correlations of intravesical volumes and pressures required to achieve maximum distension of the midprostatic portion of the urethra with body weight and surface area were not significant. Because of the variability in intravesical volumes and pressures encountered at maximum distension of the prostatic portion of the urethra, a dose of contrast material expressed relative to body weight or surface area could not be determined for consistently providing maximum distension of the prostatic portion of the urethra.

Effects of Head Rotation and Head Tilt on Pharyngeal Pressure Events Using High Resolution Manometry.

PubMed

Kim, Cheol Ki; Ryu, Ju Seok; Song, Sun Hong; Koo, Jung Hoi; Lee, Kyung Duck; Park, Hee Sun; Oh, Yoongul; Min, Kyunghoon

2015-06-01

To observe changes in pharyngeal pressure during the swallowing process according to postures in normal individuals using high-resolution manometry (HRM). Ten healthy volunteers drank 5 mL of water twice while sitting in a neutral posture. Thereafter, they drank the same amount of water twice in the head rotation and head tilting postures. The pressure and time during the deglutition process for each posture were measured with HRM. The data obtained for these two postures were compared with those obtained from the neutral posture. The maximum pressure, area, rise time, and duration in velopharynx (VP) and tongue base (TB) were not affected by changes in posture. In comparison, the maximum pressure and the pre-upper esophageal sphincter (UES) maximum pressure of the lower pharynx in the counter-catheter head rotation posture were lower than those in the neutral posture. The lower pharynx pressure in the catheter head tilting posture was higher than that in the counter-catheter head tilting. The changes in the VP peak and epiglottis, VP and TB peaks, and the VP onset and post-UES time intervals were significant in head tilting and head rotation toward the catheter postures, as compared with neutral posture. The pharyngeal pressure and time parameter analysis using HRM determined the availability of head rotation as a compensatory technique for safe swallowing. Tilting the head smoothes the progress of food by increasing the pressure in the pharynx.

Effects of Head Rotation and Head Tilt on Pharyngeal Pressure Events Using High Resolution Manometry

PubMed Central

Kim, Cheol Ki; Song, Sun Hong; Koo, Jung Hoi; Lee, Kyung Duck; Park, Hee Sun; Oh, Yoongul; Min, Kyunghoon

2015-01-01

Objective To observe changes in pharyngeal pressure during the swallowing process according to postures in normal individuals using high-resolution manometry (HRM). Methods Ten healthy volunteers drank 5 mL of water twice while sitting in a neutral posture. Thereafter, they drank the same amount of water twice in the head rotation and head tilting postures. The pressure and time during the deglutition process for each posture were measured with HRM. The data obtained for these two postures were compared with those obtained from the neutral posture. Results The maximum pressure, area, rise time, and duration in velopharynx (VP) and tongue base (TB) were not affected by changes in posture. In comparison, the maximum pressure and the pre-upper esophageal sphincter (UES) maximum pressure of the lower pharynx in the counter-catheter head rotation posture were lower than those in the neutral posture. The lower pharynx pressure in the catheter head tilting posture was higher than that in the counter-catheter head tilting. The changes in the VP peak and epiglottis, VP and TB peaks, and the VP onset and post-UES time intervals were significant in head tilting and head rotation toward the catheter postures, as compared with neutral posture. Conclusion The pharyngeal pressure and time parameter analysis using HRM determined the availability of head rotation as a compensatory technique for safe swallowing. Tilting the head smoothes the progress of food by increasing the pressure in the pharynx. PMID:26161349

A 15 kWe (nominal) solar thermal-electric power conversion concept definition study: Steam Rankin reciprocator system

NASA Technical Reports Server (NTRS)

Wingenback, W.; Carter, J., Jr.

1979-01-01

A conceptual design of a 3600 rpm reciprocation expander was developed for maximum thermal input power of 80 kW. The conceptual design covered two engine configurations; a single cylinder design for simple cycle operation and a two cylinder design for reheat cycle operation. The reheat expander contains a high pressure cylinder and a low pressure cylinder with steam being reheated to the initial inlet temperature after expansion in the high pressure cylinder. Power generation is accomplished with a three-phase induction motor coupled directly to the expander and connected electrically to the public utility power grid. The expander, generator, water pump and control system weigh 297 kg and are dish mounted. The steam condenser, water tank and accessory pumps are ground based. Maximum heat engine efficiency is 33 percent: maximum power conversion efficiency is 30 percent. Total cost is $3,307 or $138 per kW of maximum output power.

Axisymmetric inlet minimum weight design method

NASA Technical Reports Server (NTRS)

Nadell, Shari-Beth

1995-01-01

An analytical method for determining the minimum weight design of an axisymmetric supersonic inlet has been developed. The goal of this method development project was to improve the ability to predict the weight of high-speed inlets in conceptual and preliminary design. The initial model was developed using information that was available from inlet conceptual design tools (e.g., the inlet internal and external geometries and pressure distributions). Stiffened shell construction was assumed. Mass properties were computed by analyzing a parametric cubic curve representation of the inlet geometry. Design loads and stresses were developed at analysis stations along the length of the inlet. The equivalent minimum structural thicknesses for both shell and frame structures required to support the maximum loads produced by various load conditions were then determined. Preliminary results indicated that inlet hammershock pressures produced the critical design load condition for a significant portion of the inlet. By improving the accuracy of inlet weight predictions, the method will improve the fidelity of propulsion and vehicle design studies and increase the accuracy of weight versus cost studies.

Effect of Degeneration on Fluid-Solid Interaction within Intervertebral Disk Under Cyclic Loading - A Meta-Model Analysis of Finite Element Simulations.

PubMed

Nikkhoo, Mohammad; Khalaf, Kinda; Kuo, Ya-Wen; Hsu, Yu-Chun; Haghpanahi, Mohammad; Parnianpour, Mohamad; Wang, Jaw-Lin

2015-01-01

The risk of low back pain resulted from cyclic loadings is greater than that resulted from prolonged static postures. Disk degeneration results in degradation of disk solid structures and decrease of water contents, which is caused by activation of matrix digestive enzymes. The mechanical responses resulted from internal solid-fluid interactions of degenerative disks to cyclic loadings are not well studied yet. The fluid-solid interactions in disks can be evaluated by mathematical models, especially the poroelastic finite element (FE) models. We developed a robust disk poroelastic FE model to analyze the effect of degeneration on solid-fluid interactions within disk subjected to cyclic loadings at different loading frequencies. A backward analysis combined with in vitro experiments was used to find the elastic modulus and hydraulic permeability of intact and enzyme-induced degenerated porcine disks. The results showed that the averaged peak-to-peak disk deformations during the in vitro cyclic tests were well fitted with limited FE simulations and a quadratic response surface regression for both disk groups. The results showed that higher loading frequency increased the intradiscal pressure, decreased the total fluid loss, and slightly increased the maximum axial stress within solid matrix. Enzyme-induced degeneration decreased the intradiscal pressure and total fluid loss, and barely changed the maximum axial stress within solid matrix. The increase of intradiscal pressure and total fluid loss with loading frequency was less sensitive after the frequency elevated to 0.1 Hz for the enzyme-induced degenerated disk. Based on this study, it is found that enzyme-induced degeneration decreases energy attenuation capability of disk, but less change the strength of disk.

Effect of Degeneration on Fluid–Solid Interaction within Intervertebral Disk Under Cyclic Loading – A Meta-Model Analysis of Finite Element Simulations

PubMed Central

Nikkhoo, Mohammad; Khalaf, Kinda; Kuo, Ya-Wen; Hsu, Yu-Chun; Haghpanahi, Mohammad; Parnianpour, Mohamad; Wang, Jaw-Lin

2015-01-01

The risk of low back pain resulted from cyclic loadings is greater than that resulted from prolonged static postures. Disk degeneration results in degradation of disk solid structures and decrease of water contents, which is caused by activation of matrix digestive enzymes. The mechanical responses resulted from internal solid–fluid interactions of degenerative disks to cyclic loadings are not well studied yet. The fluid–solid interactions in disks can be evaluated by mathematical models, especially the poroelastic finite element (FE) models. We developed a robust disk poroelastic FE model to analyze the effect of degeneration on solid–fluid interactions within disk subjected to cyclic loadings at different loading frequencies. A backward analysis combined with in vitro experiments was used to find the elastic modulus and hydraulic permeability of intact and enzyme-induced degenerated porcine disks. The results showed that the averaged peak-to-peak disk deformations during the in vitro cyclic tests were well fitted with limited FE simulations and a quadratic response surface regression for both disk groups. The results showed that higher loading frequency increased the intradiscal pressure, decreased the total fluid loss, and slightly increased the maximum axial stress within solid matrix. Enzyme-induced degeneration decreased the intradiscal pressure and total fluid loss, and barely changed the maximum axial stress within solid matrix. The increase of intradiscal pressure and total fluid loss with loading frequency was less sensitive after the frequency elevated to 0.1 Hz for the enzyme-induced degenerated disk. Based on this study, it is found that enzyme-induced degeneration decreases energy attenuation capability of disk, but less change the strength of disk. PMID:25674562

Fast response air-to-fuel ratio measurements using a novel device based on a wide band lambda sensor

NASA Astrophysics Data System (ADS)

Regitz, S.; Collings, N.

2008-07-01

A crucial parameter influencing the formation of pollutant gases in internal combustion engines is the air-to-fuel ratio (AFR). During transients on gasoline and diesel engines, significant AFR excursions from target values can occur, but cycle-by-cycle AFR resolution, which is helpful in understanding the origin of deviations, is difficult to achieve with existing hardware. This is because current electrochemical devices such as universal exhaust gas oxygen (UEGO) sensors have a time constant of 50-100 ms, depending on the engine running conditions. This paper describes the development of a fast reacting device based on a wide band lambda sensor which has a maximum time constant of ~20 ms and enables cyclic AFR measurements for engine speeds of up to ~4000 rpm. The design incorporates a controlled sensor environment which results in insensitivity to sample temperature and pressure. In order to guide the development process, a computational model was developed to predict the effect of pressure and temperature on the diffusion mechanism. Investigations regarding the sensor output and response were carried out, and sensitivities to temperature and pressure are examined. Finally, engine measurements are presented.

Applications and Engineering Analysis of Lotus Roots under External Water Pressure

PubMed Central

Wang, Chang Jiang; Mynors, Diane

2016-01-01

Engineers can learn from nature for inspirations to create new designs. The internal structure of lotus roots with several oval holes was studied in this paper for engineering inspirations. The structural performance of lotus roots under outside water pressure was simulated and compared with various cross-sectional areas. The distribution of stresses in the cross-sectional area of lotus roots was analysed and presented. It was found that the maximum compressive stresses in the cross-sectional area of lotus roots were occurring at the long axis ends of the holes. This was very different from that of circular holes. Further analysis on the triaxiality factors revealed that the cross-sectional area of the lotus root resulted in large areas of high triaxiality factors. The resulting hydrostatic stress in the cross-sectional area of lotus root ranges from zero to 2.7 times the applied outside pressure. In contrast, the hydrostatic stress in a cylindrical cross-sectional area is a fixed value. The study showed that the lotus root and the orientation of the oval holes could be mimicked in the design of new structures, for example, underwater pipes and vessels. PMID:28127228

Effective inactivation of Saccharomyces cerevisiae in minimally processed Makgeolli using low-pressure homogenization-based pasteurization.

PubMed

Bak, Jin Seop

2015-01-01

In order to address the limitations associated with the inefficient pasteurization platform used to make Makgeolli, such as the presence of turbid colloidal dispersions in suspension, commercially available Makgeolli was minimally processed using a low-pressure homogenization-based pasteurization (LHBP) process. This continuous process demonstrates that promptly reducing the exposure time to excessive heat using either large molecules or insoluble particles can dramatically improve internal quality and decrease irreversible damage. Specifically, optimal homogenization increased concomitantly with physical parameters such as colloidal stability (65.0% of maximum and below 25-μm particles) following two repetitions at 25.0 MPa. However, biochemical parameters such as microbial population, acidity, and the presence of fermentable sugars rarely affected Makgeolli quality. Remarkably, there was a 4.5-log reduction in the number of Saccharomyces cerevisiae target cells at 53.5°C for 70 sec in optimally homogenized Makgeolli. This value was higher than the 37.7% measured from traditionally pasteurized Makgeolli. In contrast to the analytical similarity among homogenized Makgeollis, our objective quality evaluation demonstrated significant differences between pasteurized (or unpasteurized) Makgeolli and LHBP-treated Makgeolli. Low-pressure homogenization-based pasteurization, Makgeolli, minimal processing-preservation, Saccharomyces cerevisiae, suspension stability.

SpaceX Dragon Air Circulation System

NASA Technical Reports Server (NTRS)

Hernandez, Brenda; Piatrovich, Siarhei; Prina, Mauro

2011-01-01

The Dragon capsule is a reusable vehicle being developed by Space Exploration Technologies (SpaceX) that will provide commercial cargo transportation to the International Space Station (ISS). Dragon is designed to be a habitable module while it is berthed to ISS. As such, the Dragon Environmental Control System (ECS) consists of pressure control and pressure equalization, air sampling, fire detection, illumination, and an air circulation system. The air circulation system prevents pockets of stagnant air in Dragon that can be hazardous to the ISS crew. In addition, through the inter-module duct, the air circulation system provides fresh air from ISS into Dragon. To utilize the maximum volume of Dragon for cargo packaging, the Dragon ECS air circulation system is designed around cargo rack optimization. At the same time, the air circulation system is designed to meet the National Aeronautics Space Administration (NASA) inter-module and intra-module ventilation requirements and acoustic requirements. A flight like configuration of the Dragon capsule including the air circulation system was recently assembled for testing to assess the design for inter-module and intra-module ventilation and acoustics. The testing included the Dragon capsule, and flight configuration in the pressure section with cargo racks, lockers, all of the air circulation components, and acoustic treatment. The air circulation test was also used to verify the Computational Fluid Dynamics (CFD) model of the Dragon capsule. The CFD model included the same Dragon internal geometry that was assembled for the test. This paper will describe the Dragon air circulation system design which has been verified by testing the system and with CFD analysis.

Perceived social pressures and the internalization of the mesomorphic ideal: The role of drive for muscularity and autonomy in physically active men.

PubMed

Edwards, Christian; Tod, David; Molnar, Gyozo; Markland, David

2016-03-01

We examined if there were both direct and indirect relationships (via the drive for muscularity) between the perceived pressure to be muscular and internalization of the mesomorphic ideal, and if autonomy moderates these relationships in physically active men. A sample of 330 men, who were undergraduate students studying sport, completed the Behavioral Regulation in Exercise Questionnaire-2, the Mesomorphic Ideal Internalization subscale of the revised male version Sociocultural Attitudes Toward Appearance Questionnaire, the Perceived Sociocultural Pressure Scale-Modified, and the Drive for Muscularity Scale Attitudes subscale. Perceived pressure predicted internalization directly, and indirectly through the drive for muscularity. The direct relationship between pressure and internalization was weaker under higher levels of autonomy. The indirect path, via drive for muscularity, was stronger under higher levels of autonomy. These results provide insights into why men vary in the degree to which they internalize pressure to develop a mesomorphic ideal, supporting further examination of autonomy. Copyright © 2015 Elsevier Ltd. All rights reserved.

Effect of abdominal insufflation for laparoscopy on intracranial pressure.

PubMed

Kamine, Tovy Haber; Papavassiliou, Efstathios; Schneider, Benjamin E

2014-04-01

Increased abdominal pressure may have a negative effect on intracranial pressure (ICP). Human data on the effects of laparoscopy on ICP are lacking. We retrospectively reviewed laparoscopic operations for ventriculoperitoneal shunt placement to determine the effect of insufflation on ICP. Nine patients underwent insufflation with carbon dioxide (CO(2)) at pressures ranging from 8 to 15 mm Hg and ICP measured through a ventricular catheter. We used a paired t test to compare ICP with insufflation and desufflation. Linear regression correlated insufflation pressure with ICP. The mean ICP increase with 15-mm Hg insufflation is 7.2 (95% CI, 5.4-9.1 [P < .001]) cm H(2)O. The increase in ICP correlated with increasing insufflation pressure (P = .04). Maximum ICP recorded was 25 cm H(2)O. Intracranial pressure significantly increases with abdominal insufflation and correlates with laparoscopic insufflation pressure. The maximum ICP measured was a potentially dangerous 25 cm H(2)O. Laparoscopy should be used cautiously in patients with a baseline elevated ICP or head trauma.

Water Pressure Distribution on a Twin-Float Seaplane

NASA Technical Reports Server (NTRS)

Thompson, F L

1930-01-01

This is the second of a series of investigations to determine water pressure distribution on various types of seaplane floats and hulls, and was conducted on a twin-float seaplane. It consisted of measuring water pressures and accelerations on a TS-1 seaplane during numerous landing and taxiing maneuvers at various speeds and angles. The results show that water pressures as great as 10 lbs. per sq. in.may occur at the step in various maneuvers and that pressures of approximately the same magnitude occur at the stern and near the bow in hard pancake landings with the stern way down. At the other parts of the float the pressures are less and are usually zero or slightly negative for some distance abaft the step. A maximum negative pressure of 0.87 lb. Per square inch was measured immediately abaft the step. The maximum positive pressures have a duration of approximately one-twentieth to one-hundredth second at any given location and are distributed over a very limited area at any particular instant.

49 CFR 178.347-4 - Pressure relief.

Code of Federal Regulations, 2010 CFR

2010-10-01

... adequate vapor and liquid capacity to limit the tank pressure to the cargo tank test pressure at maximum... 49 Transportation 2 2010-10-01 2010-10-01 false Pressure relief. 178.347-4 Section 178.347-4... Specifications for Containers for Motor Vehicle Transportation § 178.347-4 Pressure relief. (a) Each cargo tank...

The effectiveness of combining inspiratory muscle training with manual therapy and a therapeutic exercise program on maximum inspiratory pressure in adults with asthma: a randomized clinical trial.

PubMed

López-de-Uralde-Villanueva, Ibai; Candelas-Fernández, Pablo; de-Diego-Cano, Beatriz; Mínguez-Calzada, Orcález; Del Corral, Tamara

2018-06-01

The objective of this study was to evaluate whether the addition of manual therapy and therapeutic exercise protocol to inspiratory muscle training was more effective in improving maximum inspiratory pressure than inspiratory muscle training in isolation. This is a single-blinded, randomized controlled trial. In total, 43 patients with asthma were included in this study. The patients were allocated into one of the two groups: (1) inspiratory muscle training ( n = 21; 20-minute session) or (2) inspiratory muscle training (20-minute session) combined with a program of manual therapy (15-minute session) and therapeutic exercise (15-minute session; n = 22). All participants received 12 sessions, two days/week, for six weeks and performed the domiciliary exercises protocol. The main measures such as maximum inspiratory pressure, spirometric measures, forward head posture, and thoracic kyphosis were recorded at baseline and after the treatment. For the per-protocol analysis, between-group differences at post-intervention were observed in maximum inspiratory pressure (19.77 cmH 2 O (11.49-28.04), P < .05; F = 22.436; P < .001; η 2 p  = 0.371) and forward head posture (-1.25 cm (-2.32 to -0.19), P < .05; F = 5.662; P = .022; η 2 p  = 0.13). The intention-to-treat analysis showed the same pattern of findings. The inspiratory muscle training combined with a manual therapy and therapeutic exercise program is more effective than its application in isolation for producing short-term maximum inspiratory pressure and forward head posture improvements in patients with asthma.

Increasing preferred step rate during running reduces plantar pressures.

PubMed

Gerrard, James M; Bonanno, Daniel R

2018-01-01

Increasing preferred step rate during running is a commonly used strategy in the management of running-related injuries. This study investigated the effect of different step rates on plantar pressures during running. Thirty-two healthy runners ran at a comfortable speed on a treadmill at five step rates (preferred, ±5%, and ±10%). For each step rate, plantar pressure data were collected using the pedar-X in-shoe system. Compared to running with a preferred step rate, a 10% increase in step rate significantly reduced peak pressure (144.5±46.5 vs 129.3±51 kPa; P=.033) and maximum force (382.3±157.6 vs 334.0±159.8 N; P=.021) at the rearfoot, and reduced maximum force (426.4±130.4 vs 400.0±116.6 N; P=.001) at the midfoot. In contrast, a 10% decrease in step rate significantly increased peak pressure (144.5±46.5 vs 161.5±49.3 kPa; P=.011) and maximum force (382.3±157.6 vs 425.4±155.3 N; P=.032) at the rearfoot. Changing step rate by 5% provided no effect on plantar pressures, and no differences in plantar pressures were observed at the medial forefoot, lateral forefoot or hallux between the step rates. This study's findings indicate that increasing preferred step rate by 10% during running will reduce plantar pressures at the rearfoot and midfoot, while decreasing step rate by 10% will increase plantar pressures at the rearfoot. However, changing preferred step rate by 5% will provide no effect on plantar pressures, and forefoot pressures are unaffected by changes in step rate. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Tibiofemoral joint contact area and pressure after single- and double-bundle anterior cruciate ligament reconstruction.

PubMed

Morimoto, Yusuke; Ferretti, Mario; Ekdahl, Max; Smolinski, Patrick; Fu, Freddie H

2009-01-01

The purpose of this study was to compare the tibiofemoral contact area and pressure after single-bundle (SB) and double-bundle (DB) anterior cruciate ligament (ACL) reconstruction by use of 2 femoral and 2 tibial tunnels in intact cadaveric knees. Tibiofemoral contact area and mean and maximum pressures were measured by pressure-sensitive film (Fujifilm, Valhalla, NY) inserted between the tibia and femur. The knee was subjected to a 1,000-N axial load by use of a uniaxial testing machine at 0 degrees , 15 degrees , 30 degrees , and 45 degrees of flexion. Three conditions were evaluated: (1) intact ACL, (2) SB ACL reconstruction (n = 10 knees), and (3) DB ACL reconstruction (n = 9 knees). When compared with the intact knee, DB ACL reconstruction showed no significant difference in tibiofemoral contact area and mean and maximum pressures. SB ACL reconstruction had a significantly smaller contact area on the lateral and medial tibiofemoral joints at 30 degrees and 15 degrees of flexion. SB ACL reconstruction also had significantly higher mean pressures at 15 degrees of flexion on the medial tibiofemoral joint and at 0 degrees and 15 degrees of flexion on the lateral tibiofemoral joint, as well as significantly higher maximum pressures at 15 degrees of flexion on the lateral tibiofemoral joint. SB ACL reconstruction resulted in a significantly smaller tibiofemoral contact area and higher pressures. DB ACL more closely restores the normal contact area and pressure mainly at low flexion angles. Our findings suggest that the changes in the contact area and pressures after SB ACL reconstruction may be one of the causes of osteoarthritis on long-term follow-up. DB ACL reconstruction may reduce the incidence of osteoarthritis by closely restoring contact area and pressure.

Numerical simulation of CO2 scroll compressor in transcritical compression cycle

NASA Astrophysics Data System (ADS)

Wang, Hongli; Tian, JingRui; Du, Yuanhang; Hou, Xiujuan

2018-05-01

Based on the theory of thermodynamics and kinetics, the mathematical model of an orbiting scroll was established and the stress deformations were employed by ANSYS software. Under the action of pressure load, the results show that the serious displacement part is located in the center of the gear head and the maximum deformation is about 7.33 μm. The maximum radial displacement is about 4.42 μm. The maximum radial stress point occurs in the center of the gear head and the maximum stress is about 40.9 MPa. The maximum axial displacement is about 2.31 μm. The maximum axial stress point occurs in the gear head and the maximum stress is about 44.7 MPa. Under the action of temperature load, the results show that the serious deformation part is located in the center of the gear head and the maximum deformation is about 6.3 μm. The maximum thermal stress occurs in the center of the gear head and the maximum thermal stress is about 86.36 MPa. Under the combined action of temperature load and pressure load, the results show that the serious deformation part and the maximum stress are located in the center of the gear head, and the value are about 7.79 μm and 74.19 MPa, respectively.

Estimation of Bladder Contractility From Intravesical Pressure–Volume Measurements

PubMed Central

Fry, Christopher H.; Gammie, Andrew; Drake, Marcus John; Abrams, Paul; Kitney, Darryl Graham; Vahabi, Bahareh

2017-01-01

Aims To describe parameters from urodynamic pressure recordings that describe urinary bladder contractility through the use of principles of muscle mechanics. Methods Subtracted detrusor pressure and voided flow were recorded from patients undergoing filling cystometry. The isovolumetric increase of detrusor pressure, P, of a voluntary bladder contraction before voiding was used to generate a plot of (dP/dt)/P versus P. Extrapolation of the plot to the y-axis and the x-axis generated a contractility parameter, vCE (the maximum rate of pressure development) and the maximum isovolumetric pressure, P0, respectively. Similar curves were obtained in ex vivo pig bladders with different concentrations of the inotropic agent carbachol and shown in a supplement. Results Values of vCE, but not P0, diminished with age in female subjects. vCE was most significantly associated with the 20–80% duration of isovolumetric contraction t20–80;and a weaker association with maximum flow rate and BCI in women. P0 was not associated with any urodynamic variable in women, but in men was with t20–80 and isovolumetric pressure indices. Conclusions The rate of isovolumetric subtracted detrusor pressure (t20–80) increase shows a very significant association with indices of bladder contractility as derived from a derived force–velocity curve. We propose that t20–80 is a detrusor contractility parameter (DCP). PMID:27265671

Modeling of coupled thermodynamic and geomechanical performance of underground compressed air energy storage in lined rock caverns

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

Rutqvist, Jonny; Kim, Hyung-Mok; Ryu, Dong-Woo

We applied coupled nonisothermal, multiphase fluid flow and geomechanical numerical modeling to study the coupled thermodynamic and geomechanical performance of underground compressed air energy storage (CAES) in concrete-lined rock caverns. The paper focuses on CAES in lined caverns at relatively shallow depth (e.g., 100 m depth) in which a typical CAES operational pressure of 5 to 8 MPa is significantly higher than both ambient fluid pressure and in situ stress. We simulated a storage operation that included cyclic compression and decompression of air in the cavern, and investigated how pressure, temperature and stress evolve over several months of operation. Wemore » analyzed two different lining options, both with a 50 cm thick low permeability concrete lining, but in one case with an internal synthetic seal such as steel or rubber. For our simulated CAES system, the thermodynamic analysis showed that 96.7% of the energy injected during compression could be recovered during subsequent decompression, while 3.3% of the energy was lost by heat conduction to the surrounding media. Our geomechanical analysis showed that tensile effective stresses as high as 8 MPa could develop in the lining as a result of the air pressure exerted on the inner surface of the lining, whereas thermal stresses were relatively smaller and compressive. With the option of an internal synthetic seal, the maximum effective tensile stress was reduced from 8 to 5 MPa, but was still in substantial tension. We performed one simulation in which the tensile tangential stresses resulted in radial cracks and air leakage though the lining. This air leakage, however, was minor (about 0.16% of the air mass loss from one daily compression) in terms of CAES operational efficiency, and did not significantly impact the overall energy balance of the system. However, despite being minor in terms of energy balance, the air leakage resulted in a distinct pressure increase in the surrounding rock that could be quickly detected using pressure monitoring outside the concrete lining.« less

Effect of Background Pressure on the Performance and Plume of the HiVHAc Hall Thruster

NASA Technical Reports Server (NTRS)

Huang, Wensheng; Kamhawi, Hani; Haag, Thomas

2013-01-01

During the Single String Integration Test of the NASA HiVHAc Hall thruster, a number of plasma diagnostics were implemented to study the effect of varying facility background pressure on thruster operation. These diagnostics include thrust stand, Faraday probe, ExB probe, and retarding potential analyzer. The test results indicated a rise in thrust and discharge current with background pressure. There was also a decrease in ion energy per charge, an increase in multiply-charged species production, a decrease in plume divergence, and a decrease in ion beam current with increasing background pressure. A simplified ingestion model was applied to determine the maximum acceptable background pressure for thrust measurement. The maximum acceptable ingestion percentage was found to be around 1%. Examination of the diagnostics results suggest the ionization and acceleration zones of the thruster were shifting upstream with increasing background pressure.

Advanced cooling techniques for high-pressure hydrocarbon-fueled engines

NASA Technical Reports Server (NTRS)

Cook, R. T.

1979-01-01

The regenerative cooling limits (maximum chamber pressure) for 02/hydrocarbon gas generator and staged combustion cycle rocket engines over a thrust range of 89,000 N (20,000lbf) to 2,669,000 N (600,000 lbf) for a reusable life of 250 missions were defined. Maximum chamber pressure limits were first determined for the three propellant combinations (O2/CH4, O2/C3H8, and O2/RP-1 without a carbon layer (unenhanced designs). Chamber pressure cooling enhancement limits were then established for seven thermal barriers. The thermal barriers evaluated for these designs were: carbon layer, ceramic coating, graphite liner, film cooling, transpiration cooling, zoned combustion, and a combination of two of the above. All fluid barriers were assessed a 3 percent performance loss. Sensitivity studies were then conducted to determine the influence of cycle life and RP-1 decomposition temperature on chamber pressure limits. Chamber and nozzle design parameters are presented for the unenahanced and enhanced designs. The maximum regenerative cooled chamber pressure limits were attained with the O2/CH4 propellant combination. The O2/RP-1 designs relied on a carbon layer and liquid gas injection chamber contours, short chamber, to be competitive with the other two propellant combinations. This was attributed to the low decomposition temperature of RP-1.

Elevation of internal auditory canal pressure by vestibular schwannomas.

PubMed

Badie, B; Pyle, G M; Nguyen, P H; Hadar, E J

2001-09-01

The exact mechanism of hearing loss, the most common presenting symptom in patients with vestibular schwannomas, remains unclear. To test whether increased pressure in the internal auditory canal from tumor growth is responsible for this clinical finding, the intracanalicular pressure in patients harboring these tumors was measured. Prospective study. Tertiary referral hospital. Fifteen consecutive patients undergoing a retrosigmoid approach for resection of vestibular schwannomas were included in the study. The intracanalicular pressure in every patient was measured by introducing a pressure microsensor into the internal auditory canal. The pressure readings, which were performed before tumor resection, were then correlated with tumor size and respective preoperative hearing status. Placement of the pressure monitor into the internal auditory canal revealed a biphasic waveform in every patient. Whereas the mean intracanalicular pressure was 20 mm Hg, there was significant variability among patients (range, 1-45 mm Hg). The intracanalicular pressure directly correlated with the amount of tumor in the internal auditory canal (r > 0.63, p < 0.012) but not with the total tumor size (r 0.075). Furthermore, eight patients with class A preoperative hearing (American Academy of Otolaryngology-Head and Neck Surgery classification) had lower intracanalicular pressures than did five patients with class B hearing (16 +/- 5 vs. 28 +/- 4). Although this observation suggested an inverse correlation between the intracanalicular pressure and hearing function, the difference between the two groups was not statistically significant (p = 0.14). Pressure on the cochlear nerve as a result of tumor growth in the internal auditory canal may be responsible for hearing loss in patients with vestibular schwannomas. Modification of surgical techniques to address the elevated intracanalicular pressure may be beneficial in improving hearing preservation in these patients.

Variation of plantar pressure in Chinese diabetes mellitus.

PubMed

Yang, Chuan; Xiao, Huisheng; Wang, Chuan; Mai, LiFang; Liu, Dan; Qi, Yiqing; Ren, Meng; Yan, Li

2015-01-01

To investigate dynamic changes in plantar pressure in Chinese diabetes mellitus patients and to provide a basis for further preventing diabetic foot. This is a cross-sectional investigation including 649 Chinese diabetes mellitus patients (diabetes group) and 808 "normal" Chinese persons (nondiabetes group) with normal blood glucose levels. All the subjects provided a complete medical history and underwent a physical examination and a 75-g oral glucose tolerance test. All subjects walked barefoot with their usual gait, and their dynamic plantar forces were measured using the one-step method with a plantar pressure measurement instrument; 5 measurements were performed for each foot. No significant differences were found in age, height, body weight, or body mass index between the two groups. The fasting blood glucose levels, plantar contact time, maximum force, pressure-time integrals and force-time integrals in the diabetes group were significantly higher than those in the nondiabetes group (p < 0.05). However, the maximum pressure was significantly higher in the nondiabetes group than in the diabetes group (p < 0.05). No difference was found in the contact areas between the two groups (p > 0.05). The maximum plantar force distributions were essentially the same, with the highest force found for the medial heel, followed by the medial forefoot and the first toe. The peak plantar pressure was located at the medial forefoot for the nondiabetes group and at the hallucis for the diabetes group. In the diabetes group, the momentum in each plantar region was higher than that in the nondiabetes group; this difference was especially apparent in the heel, the lateral forefoot and the hallucis. The dynamic plantar pressures in diabetic patients differ from those in nondiabetic people with increased maximum force and pressure, a different distribution pattern and significantly increased momentum, which may lead to the formation of foot ulcers. © 2015 by the Wound Healing Society.

Effects of internal yaw-vectoring devices on the static performance of a pitch-vectoring nonaxisymmetric convergent-divergent nozzle

NASA Technical Reports Server (NTRS)

Asbury, Scott C.

1993-01-01

An investigation was conducted in the static test facility of the Langley 16-Foot Transonic Tunnel to evaluate the internal performance of a nonaxisymmetric convergent divergent nozzle designed to have simultaneous pitch and yaw thrust vectoring capability. This concept utilized divergent flap deflection for thrust vectoring in the pitch plane and flow-turning deflectors installed within the divergent flaps for yaw thrust vectoring. Modifications consisting of reducing the sidewall length and deflecting the sidewall outboard were investigated as means to increase yaw-vectoring performance. This investigation studied the effects of multiaxis (pitch and yaw) thrust vectoring on nozzle internal performance characteristics. All tests were conducted with no external flow, and nozzle pressure ratio was varied from 2.0 to approximately 13.0. The results indicate that this nozzle concept can successfully generate multiaxis thrust vectoring. Deflection of the divergent flaps produced resultant pitch vector angles that, although dependent on nozzle pressure ratio, were nearly equal to the geometric pitch vector angle. Losses in resultant thrust due to pitch vectoring were small or negligible. The yaw deflectors produced resultant yaw vector angles up to 21 degrees that were controllable by varying yaw deflector rotation. However, yaw deflector rotation resulted in significant losses in thrust ratios and, in some cases, nozzle discharge coefficient. Either of the sidewall modifications generally reduced these losses and increased maximum resultant yaw vector angle. During multiaxis (simultaneous pitch and yaw) thrust vectoring, little or no cross coupling between the thrust vectoring processes was observed.

Internal Progressive Failure in Deep-Seated Landslides

NASA Astrophysics Data System (ADS)

Yerro, Alba; Pinyol, Núria M.; Alonso, Eduardo E.

2016-06-01

Except for simple sliding motions, the stability of a slope does not depend only on the resistance of the basal failure surface. It is affected by the internal distortion of the moving mass, which plays an important role on the stability and post-failure behaviour of a landslide. The paper examines the stability conditions and the post-failure behaviour of a compound landslide whose geometry is inspired by one of the representative cross-sections of Vajont landslide. The brittleness of the mobilized rock mass was described by a strain-softening Mohr-Coulomb model, whose parameters were derived from previous contributions. The analysis was performed by means of a MPM computer code, which is capable of modelling the whole instability procedure in a unified calculation. The gravity action has been applied to initialize the stress state. This step mobilizes part of the strength along a shearing band located just above the kink of the basal surface, leading to the formation a kinematically admissible mechanism. The overall instability is triggered by an increase of water level. The increase of pore water pressures reduces the effective stresses within the slope and it leads to a progressive failure mechanism developing along an internal shearing band which controls the stability of the compound slope. The effect of the basal shearing resistance has been analysed during the post-failure stage. If no shearing strength is considered (as predicted by a thermal pressurization analysis), the model predicts a response similar to actual observations, namely a maximum sliding velocity of 25 m/s and a run-out close to 500 m.

Effect of internal stress on the electro-optical behaviour of Al-doped ZnO transparent conductive thin films

NASA Astrophysics Data System (ADS)

Proost, J.; Henry, F.; Tuyaerts, R.; Michotte, S.

2016-08-01

In this work, we will report on scientific efforts aimed at unraveling the quantitative effect of elastic strain on the electro-optical behaviour of Al-doped zinc oxide (AZO). AZO thin films have been deposited by reactive magnetron sputtering to thicknesses from 300 to 500 nm, both on extra-clear glass substrates as well as on oxidised Si wafers. This resulted in both cases in polycrystalline, strongly textured (002) films. During deposition, the internal stress evolution in the growing film was monitored in-situ using high resolution curvature measurements. The resulting growth-induced elastic strain, which was found to depend heavily on the oxygen partial pressure, could further be modulated by appropriately choosing the deposition temperature. The latter also induces an additional extrinsic thermal stress component, whose sign depends on the substrate used. As such, a wide range of biaxial internal stresses could be achieved, from -600 MPa in compression up to 800 MPa in tension. The resulting charge carrier mobilities, obtained independently from room temperature Hall measurements, were found to range between 5 and 25 cm2/V s. Interestingly, the maximum mobility occurred at the zero-stress condition, and together with a charge carrier concentration of about 8 × 1020 cm-3, this gave rise to a resistivity of only 300 μΩ cm. From the stress-dependent optical transmission spectra in the range of 200-1000 nm, the pressure coefficient of the optical bandgap was estimated from the corresponding Tauc plots to be 31 meV/GPa, indicating a very high strain-sensitivity as well.

Fundamental Interactions in Gasoline Compression Ignition Engines with Fuel Stratification

NASA Astrophysics Data System (ADS)

Wolk, Benjamin Matthew

Transportation accounted for 28% of the total U.S. energy demand in 2011, with 93% of U.S. transportation energy coming from petroleum. The large impact of the transportation sector on global climate change necessitates more-efficient, cleaner-burning internal combustion engine operating strategies. One such strategy that has received substantial research attention in the last decade is Homogeneous Charge Compression Ignition (HCCI). Although the efficiency and emissions benefits of HCCI are well established, practical limits on the operating range of HCCI engines have inhibited their application in consumer vehicles. One such limit is at high load, where the pressure rise rate in the combustion chamber becomes excessively large. Fuel stratification is a potential strategy for reducing the maximum pressure rise rate in HCCI engines. The aim is to introduce reactivity gradients through fuel stratification to promote sequential auto-ignition rather than a bulk-ignition, as in the homogeneous case. A gasoline-fueled compression ignition engine with fuel stratification is termed a Gasoline Compression Ignition (GCI) engine. Although a reasonable amount of experimental research has been performed for fuel stratification in GCI engines, a clear understanding of how the fundamental in-cylinder processes of fuel spray evaporation, mixing, and heat release contribute to the observed phenomena is lacking. Of particular interest is gasoline's pressure sensitive low-temperature chemistry and how it impacts the sequential auto-ignition of the stratified charge. In order to computationally study GCI with fuel stratification using three-dimensional computational fluid dynamics (CFD) and chemical kinetics, two reduced mechanisms have been developed. The reduced mechanisms were developed from a large, detailed mechanism with about 1400 species for a 4-component gasoline surrogate. The two versions of the reduced mechanism developed in this work are: (1) a 96-species version and (2) a 98-species version including nitric oxide formation reactions. Development of reduced mechanisms is necessary because the detailed mechanism is computationally prohibitive in three-dimensional CFD and chemical kinetics simulations. Simulations of Partial Fuel Stratification (PFS), a GCI strategy, have been performed using CONVERGE with the 96-species reduced mechanism developed in this work for a 4-component gasoline surrogate. Comparison is made to experimental data from the Sandia HCCI/GCI engine at a compression ratio 14:1 at intake pressures of 1 bar and 2 bar. Analysis of the heat release and temperature in the different equivalence ratio regions reveals that sequential auto-ignition of the stratified charge occurs in order of increasing equivalence ratio for 1 bar intake pressure and in order of decreasing equivalence ratio for 2 bar intake pressure. Increased low- and intermediate-temperature heat release with increasing equivalence ratio at 2 bar intake pressure compensates for decreased temperatures in higher-equivalence ratio regions due to evaporative cooling from the liquid fuel spray and decreased compression heating from lower values of the ratio of specific heats. The presence of low- and intermediate-temperature heat release at 2 bar intake pressure alters the temperature distribution of the mixture stratification before hot-ignition, promoting the desired sequential auto-ignition. At 1 bar intake pressure, the sequential auto-ignition occurs in the reverse order compared to 2 bar intake pressure and too fast for useful reduction of the maximum pressure rise rate compared to HCCI. Additionally, the premixed portion of the charge auto-ignites before the highest-equivalence ratio regions. Conversely, at 2 bar intake pressure, the premixed portion of the charge auto-ignites last, after the higher-equivalence ratio regions. More importantly, the sequential auto-ignition occurs over a longer time period for 2 bar intake pressure than at 1 bar intake pressure such that a sizable reduction in the maximum pressure rise rate compared to HCCI can be achieved.

Fracture mechanics technology for optimum pressure vessel design.

NASA Technical Reports Server (NTRS)

Bjeletich, J. G.; Morton, T. M.

1973-01-01

A technique has been developed to design a maximum efficiency reliable pressure vessel of given geometry and service life. The technique for ensuring reliability of the minimum weight vessel relies on the application of linear elastic fracture mechanics and fracture mechanics concepts. The resultant design incorporates potential fatigue and stress corrosion crack extension during service of a worst case initial flaw. Maximum stress for safe life is specified by the design technique, thereby minimizing weight. Ratios of pressure and toughness parameters are employed to avoid arbitrary specification of design stress level which would lead to a suboptimum design.

Dependence of optimal separative power of the “high-speed” Iguasu centrifuge on pressure of working gas

NASA Astrophysics Data System (ADS)

Bogovalov, S. V.; Borman, V. D.; Borisevich, V. D.; Davidenko, O. V.; Tronin, I. V.; Tronin, V. N.

2016-09-01

The results of optimization calculations of the separative power of the ’’high-speed” Iguasu gas centrifuge are presented. Iguasu gas centrifuge has the rotational speed of 1000 m/s, the rotor length of 1 m. The dependence of the optimal separative power on the pressure of the working gas on the rotor wall was obtained using the numerical simulations. It is shown, that maximum of the optimal separative power corresponds to the pressure of 1100 mmHg. Maximum value of separative power is 31.9 SWU.

ANATOMY OF HELICAL EXTRAGALACTIC JETS: THE CASE OF S5 0836+710

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

Perucho, M.; Kovalev, Y. Y.; Lobanov, A. P.

Helical structures are common in extragalactic jets. They are usually attributed in the literature to periodical phenomena in the source (e.g., precession). In this work, we use very long baseline interferometry data of the radio jet in the quasar S5 0836+710 and hypothesize that the ridgeline of helical jets like this corresponds to a pressure maximum in the jet and assume that the helically twisted pressure maximum is the result of a helical wave pattern. For our study, we use observations of the jet in S5 0836+710 at different frequencies and epochs. The results show that the structures observed aremore » physical and not generated artificially by the observing arrays. Our hypothesis that the observed intensity ridgeline can correspond to a helically twisted pressure maximum is confirmed by our observational tests. This interpretation allows us to explain jet misalignment between parsec and kiloparsec scales when the viewing angle is small, and also brings us to the conclusion that high-frequency observations may show only a small region of the jet flow concentrated around the maximum pressure ridgeline observed at low frequencies. Our work provides a potential explanation for the apparent transversal superluminal speeds observed in several extragalactic jets by means of transversal shift of an apparent core position with time.« less

Comparison of Water-Load Distributions Obtained during Seaplane Landings with Bureau of Aeronautics Specifications. TED No. NACA 2413

NASA Technical Reports Server (NTRS)

Smiley, Robert F.; Haines, Gilbert A.

1949-01-01

Bureau of Aeronautics Design Specifications SS-IC-2 for water loads in sheltered water are compared with experimental water loads obtained during a full--scale landing investigation. This investigation was conducted with a JRS-1 flying boat which has a 20 degrees dead-rise V-bottom with a partial chine flare. The range of landing conditions included airspeeds between 88 and 126 feet per second, sinking speeds between 1.6 and 9.1 feet per second, flight angles less than 6 degrees, and trims between 2 degrees and 12 degrees. Landings were moderate and were made in calm water. Measurements were obtained of maximum over-all loads, maximum pitching moments, and pressure distributions. Maximum experimental loads include over-all load factors of 2g, moments of 128,000 pound-feet, and maximum local pressures greater than 40 pounds per square inch. Experimental over-all loads are approximately one-half the design values, while local pressures are of the same order as or larger than pressures calculated from specifications for plating, stringer, floor, and frame design. The value of this comparison is limited, to some extent, by the moderate conditions of the test and by the necessary simplifying assumptions used in comparing the specifications with the experimental loads.

46 CFR 61.05-10 - Boilers in service.

Code of Federal Regulations, 2010 CFR

2010-10-01

... question, shall be subjected to a hydrostatic test of 11/2 times the maximum allowable working pressure... pressure. (d) In applying hydrostatic pressure to boilers, arrangements shall be made to prevent main and auxiliary stop valves from being simultaneously subjected to the hydrostatic pressure on one side and steam...

46 CFR 64.5 - Definitions.

Code of Federal Regulations, 2011 CFR

2011-10-01

..., excluding the allowance for corrosion and the thickness for loadings other than pressure, as provided for in the ASME Code. (e) Test pressure means a hydrostatic pressure of at least one and one-half times the maximum allowable working pressure. (f) Dynamic loading conditions means the following: (1) A loading in...

46 CFR 64.5 - Definitions.

Code of Federal Regulations, 2012 CFR

2012-10-01

..., excluding the allowance for corrosion and the thickness for loadings other than pressure, as provided for in the ASME Code. (e) Test pressure means a hydrostatic pressure of at least one and one-half times the maximum allowable working pressure. (f) Dynamic loading conditions means the following: (1) A loading in...

46 CFR 64.5 - Definitions.

Code of Federal Regulations, 2013 CFR

2013-10-01

..., excluding the allowance for corrosion and the thickness for loadings other than pressure, as provided for in the ASME Code. (e) Test pressure means a hydrostatic pressure of at least one and one-half times the maximum allowable working pressure. (f) Dynamic loading conditions means the following: (1) A loading in...

46 CFR 64.5 - Definitions.

Code of Federal Regulations, 2014 CFR

2014-10-01

..., excluding the allowance for corrosion and the thickness for loadings other than pressure, as provided for in the ASME Code. (e) Test pressure means a hydrostatic pressure of at least one and one-half times the maximum allowable working pressure. (f) Dynamic loading conditions means the following: (1) A loading in...

49 CFR 229.31 - Main reservoir tests.

Code of Federal Regulations, 2010 CFR

2010-10-01

... appropriately safe environment. (d) Each aluminum main reservoir before being placed in use and at intervals... working pressure fixed by the chief mechanical officer. The test date, place, and pressure shall be... be subjected to a hydrostatic pressure of at least 25 percent more than the maximum working pressure...

Glottal volume velocity waveform characteristics in subjects with and without vocal training, related to gender, sound intensity, fundamental frequency, and age.

PubMed

Sulter, A M; Wit, H P

1996-11-01

Glottal volume velocity waveform characteristics of 224 subjects, categorized in four groups according to gender and vocal training, were determined, and their relations to sound-pressure level, fundamental frequency, intra-oral pressure, and age were analyzed. Subjects phonated at three intensity conditions. The glottal volume velocity waveforms were obtained by inverse filtering the oral flow. Glottal volume velocity waveforms were parameterized with flow-based (minimum flow, ac flow, average flow, maximum flow declination rate) and time-based parameters (closed quotient, closing quotient, speed quotient), as well as with derived parameters (vocal efficiency and glottal resistance). Higher sound-pressure levels, intra-oral pressures, and flow-parameter values (ac flow, maximum flow declination rate) were observed, when compared with previous investigations. These higher values might be the result of the specific phonation tasks (stressed /ae/ vowel in a word and a sentence) or filtering processes. Few statistically significant (p < 0.01) differences in parameters were found between untrained and trained subjects [the maximum flow declination rate and the closing quotient were higher in trained women (p < 0.001), and the speed quotient was higher in trained men (p < 0.005)]. Several statistically significant parameter differences were found between men and women [minimum flow, ac flow, average flow, maximum flow declination rate, closing quotient, glottal resistance (p < 0.001), and closed quotient (p < 0.005)]. Significant effects of intensity condition were observed on ac flow, maximum flow declination rate, closing quotient, and vocal efficiency in women (p < 0.005), and on minimum flow, ac flow, average flow, maximum flow declination rate, closed quotient, and vocal efficiency in men (p < 0.01).

Dual fuel diesel engine operation using LPG

NASA Astrophysics Data System (ADS)

Mirica, I.; Pana, C.; Negurescu, N.; Cernat, Al; Nutu, N. C.

2016-08-01

Diesel engine fuelling with LPG represents a good solution to reduce the pollutant emissions and to improve its energetic performances. The high autoignition endurance of LPG requires specialized fuelling methods. From all possible LPG fuelling methods the authors chose the diesel-gas method because of the following reasons: is easy to be implemented even at already in use engines; the engine does not need important modifications; the LPG-air mixture has a high homogeneity with favorable influences over the combustion efficiency and over the level of the pollutant emissions, especially on the nitrogen oxides emissions. This paper presents results of the theoretical and experimental investigations on operation of a LPG fuelled heavy duty diesel engine at two operating regimens, 40% and 55%. For 55% engine load is also presented the exhaust gas recirculation influence on the pollutant emission level. Was determined the influence of the diesel fuel with LPG substitution ratio on the combustion parameters (rate of heat released, combustion duration, maximum pressure, maximum pressure rise rate), on the energetic parameters (indicate mean effective pressure, effective efficiency, energetic specific fuel consumption) and on the pollutant emissions level. Therefore with increasing substitute ratio of the diesel fuel with LPG are obtained the following results: the increase of the engine efficiency, the decrease of the specific energetic consumption, the increase of the maximum pressure and of the maximum pressure rise rate (considered as criteria to establish the optimum substitute ratio), the accentuated reduction of the nitrogen oxides emissions level.

The Speed of Axial Propagation of a Cylindrical Bubble Through a Cylindrical Vortex

NASA Technical Reports Server (NTRS)

Shariff, Karim; Mansour, Nagi N. (Technical Monitor)

2002-01-01

Inspired by the rapid elongation of air columns injected into vortices by dolphins, we present an exact inviscid solution for the axial speed (assumed steady) of propagation of the tip of a semi-infinite cylindrical bubble along the axis of a cylindrical vortex. The bubble is assumed to be held at constant pressure by being connected to a reservoir, the lungs of the dolphin, say. For a given bubble pressure, there is a modest critical rotation rate above which steadily propagating bubbles exist. For a bubble at ambient pressure, the propagation speed of the bubble (relative to axial velocity within the vortex) varies between 0.5 and 0.6 of the maximum rotational speed of the vortex. Surprisingly, the bubble tip can propagate (almost as rapidly) even when the pressure minimum in the vortex core is greater than the bubble pressure; in this case, solutions exhibit a dimple on the nose of the bubble. A situation important for incipient vortex cavitation, and one which dolphins also demonstrate, is elongation of a free bubble, i.e., one whose internal pressure may vary. Under the assumption that the acceleration term is small (checked a posteriori), the steady solution is applied at each instant during the elongation. Three types of behavior are then possible depending on physical parameters and initial conditions: (A) Unabated elongation with slowly increasing bubble pressure, and nearly constant volume. Volume begins to decrease in the late stages. (B1) Elongation with decreasing bubble pressure. A limit point of the steady solution is encountered at a finite bubble length. (B2) Unabated elongation with decreasing bubble pressure and indefinite creation of volume. This is made possible by the existence of propagating solutions at bubble pressures below the minimum vortex pressure. As the bubble stretches, its radius initially decreases but then becomes constant; this is also observed in experiments on incipient vortex cavitation.

Holmium laser enucleation of the prostate combined with electrocautery resection: the mushroom technique.

PubMed

Hochreiter, Werner W; Thalmann, George N; Burkhard, Fiona C; Studer, Urs E

2002-10-01

The holmium laser allows bloodless enucleation of the prostate. A problem is how to remove a whole enucleated, free floating, large prostatic lobe from the bladder. A mechanical morcellator has been used to achieve tissue fragmentation but aspiration of and damage to the bladder wall are risks. Using the mushroom technique holmium laser enucleation and electrocautery resection can be combined without compromising the bloodless advantages of the laser procedure. We treated 156 patients with benign prostatic hyperplasia using a holmium laser with the mushroom technique. Preoperatively all patients were assessed using the International Prostate Symptom Score, maximum urine flow, ultrasound estimation of prostate volume and post-void residual urine, and pressure flow study. Laser enucleation of the prostatic lobes was performed at 66 W. Instead of releasing the lobes into the bladder they were left attached at the bladder neck by a narrow mushroom-like pedicle. At that point the vascular supply was almost completely interrupted and the lobes could easily be electroresected into small pieces without bleeding. Patients were followed 6, 12 and 24 months after the procedure. No patient had significant blood loss or signs of the transurethral resection syndrome. A total of 19 patients were treated while under oral anticoagulation without major bleeding problems. Complete followup was available on 125 patients. Median baseline International Prostate Symptom Score decreased from 20 to 3 at 6 months (p <0.05) and remained stable at 12 and 24 months. Median maximum urine flow increased from 8 to 20 ml. per second at 6, 12 and 24 months (p <0.05). Median baseline post-void residual urine decreased from 190 to 30 ml. at 6 months (p <0.05) and remained low at 20 and 30 ml. at 12 and 24 months, respectively. Urodynamic evaluation preoperatively and 6 months postoperatively was available in 83 cases. Relief of obstruction was documented with a statistically significant decrease in median detrusor pressure at maximum urine flow from 87 to 48 cm. water (p <0.05). Combining holmium laser enucleation and prostate electroresection with the mushroom technique is safe, efficient and bloodless surgical treatment for benign prostatic hyperplasia with sustained relief of obstruction. With this technique there is no need for additional devices, such as a mechanical tissue morcellator.

13 CFR 120.348 - Amount of guarantee.

Code of Federal Regulations, 2012 CFR

2012-01-01

... Purpose Loans International Trade Loans § 120.348 Amount of guarantee. The maximum loan amount for any one International Trade (IT) loan is $5,000,000. IT loans may receive a maximum guaranty of 90 percent or $4,500,000...

Measurement and interpretation of threshold stress intensity factors for steels in high-pressure hydrogen gas.

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

Dadfarnia, Mohsen; Nibur, Kevin A.; San Marchi, Christopher W.

2010-07-01

Threshold stress intensity factors were measured in high-pressure hydrogen gas for a variety of low alloy ferritic steels using both constant crack opening displacement and rising crack opening displacement procedures. The sustained load cracking procedures are generally consistent with those in ASME Article KD-10 of Section VIII Division 3 of the Boiler and Pressure Vessel Code, which was recently published to guide design of high-pressure hydrogen vessels. Three definitions of threshold were established for the two test methods: K{sub THi}* is the maximum applied stress intensity factor for which no crack extension was observed under constant displacement; K{sub THa} ismore » the stress intensity factor at the arrest position for a crack that extended under constant displacement; and K{sub JH} is the stress intensity factor at the onset of crack extension under rising displacement. The apparent crack initiation threshold under constant displacement, K{sub THi}*, and the crack arrest threshold, K{sub THa}, were both found to be non-conservative due to the hydrogen exposure and crack-tip deformation histories associated with typical procedures for sustained-load cracking tests under constant displacement. In contrast, K{sub JH}, which is measured under concurrent rising displacement and hydrogen gas exposure, provides a more conservative hydrogen-assisted fracture threshold that is relevant to structural components in which sub-critical crack extension is driven by internal hydrogen gas pressure.« less

Measurement and interpretation of threshold stress intensity factors for steels in high-pressure hydrogen gas.

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

Nibur, Kevin A.

2010-11-01

Threshold stress intensity factors were measured in high-pressure hydrogen gas for a variety of low alloy ferritic steels using both constant crack opening displacement and rising crack opening displacement procedures. The sustained load cracking procedures are generally consistent with those in ASME Article KD-10 of Section VIII Division 3 of the Boiler and Pressure Vessel Code, which was recently published to guide design of high-pressure hydrogen vessels. Three definitions of threshold were established for the two test methods: K{sub THi}* is the maximum applied stress intensity factor for which no crack extension was observed under constant displacement; K{sub THa} ismore » the stress intensity factor at the arrest position for a crack that extended under constant displacement; and K{sub JH} is the stress intensity factor at the onset of crack extension under rising displacement. The apparent crack initiation threshold under constant displacement, K{sub THi}*, and the crack arrest threshold, K{sub THa}, were both found to be non-conservative due to the hydrogen exposure and crack-tip deformation histories associated with typical procedures for sustained-load cracking tests under constant displacement. In contrast, K{sub JH}, which is measured under concurrent rising displacement and hydrogen gas exposure, provides a more conservative hydrogen-assisted fracture threshold that is relevant to structural components in which sub-critical crack extension is driven by internal hydrogen gas pressure.« less

Effect of extra-column volume on practical chromatographic parameters of sub-2-μm particle-packed columns in ultra-high pressure liquid chromatography.

PubMed

Wu, Naijun; Bradley, Ashley C; Welch, Christopher J; Zhang, Li

2012-08-01

Effects of extra-column volume on apparent separation parameters were studied in ultra-high pressure liquid chromatography with columns and inlet connection tubings of various internal diameters (id) using 50-mm long columns packed with 1.8-μm particles under isocratic conditions. The results showed that apparent retention factors were on average 5, 11, 18, and 41% lower than those corrected with extra-column volumes for 4.6-, 3.0-, 2.1-, and 1.0-mm id columns, respectively, when the extra-column volume (11.3 μL) was kept constant. Also, apparent pressures were 31, 16, 12, and 10% higher than those corrected with pressures from extra-column volumes for 4.6-, 3.0-, 2.1-, and 1.0-mm id columns at the respective optimum flow rate for a typical ultra-high pressure liquid chromatography system. The loss in apparent efficiency increased dramatically from 4.6- to 3.0- to 2.1- to 1.0-mm id columns, less significantly as retention factors increased. The column efficiency was significantly improved as the inlet tubing id was decreased for a given column. The results suggest that maximum ratio of extra-column volume to column void volume should be approximately 1:10 for column porosity more than 0.6 and a retention factor more than 5, where 80% or higher of theoretically predicted efficiency could be achieved. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Treatment strategy according to findings on pressure-flow study for women with decreased urinary flow rate.

PubMed

Tanaka, Yoshinori; Masumori, Naoya; Tsukamoto, Taiji; Furuya, Seiji; Furuya, Ryoji; Ogura, Hiroshi

2009-01-01

In women who reported a weak urinary stream, the efficacy of treatment chosen according to the urodynamic findings on pressure-flow study was prospectively evaluated. Twelve female patients with maximum flow rates of 10 mL/sec or lower were analyzed in the present study. At baseline, all underwent pressure-flow study to determine the degree of bladder outlet obstruction (BOO) and status of detrusor contractility on Schäfer's diagram. Distigmine bromide, 10 mg/d, was given to the patients with detrusor underactivity (DUA) defined as weak/very weak contractility, whereas urethral dilatation was performed using a metal sound for those with BOO (linear passive urethral resistance relation 2-6). Treatment efficacy was evaluated using the International Prostate Symptom Score (IPSS), uroflowmetry, and measurement of postvoid residual urine volume. Some patients underwent pressure-flow study after treatment. Urethral dilatation was performed for six patients with BOO, while distigmine bromide was given to the remaining six showing DUA without BOO. IPSS, QOL index, and the urinary flow rate were significantly improved in both groups after treatment. All four of the patients with BOO and one of the three with DUA but no BOO who underwent pressure-flow study after treatment showed decreased degrees of BOO and increased detrusor contractility, respectively. Both BOO and DUA cause a decreased urinary flow rate in women. In the short-term, urethral dilatation and distigmine bromide are efficacious for female patients with BOO and those with DUA, respectively.

What pressure is exerted on the retina by heavy tamponade agents?

PubMed

Wong, David; Williams, Rachel; Stappler, Theodor; Groenewald, Carl

2005-05-01

Histological changes in the retina during the use of heavy tamponade agents have been linked with the pressure on the retina caused by the increased specific gravity of the agent. This paper calculates the possible increases in pressure due to these agents and questions the validity of this argument. A model eye chamber was used to make measurements of the shape of F6H8 bubbles, with incrementally increasing volumes, and thus calculate the maximum possible increase in pressure under the tamponade agent. The maximum increase in pressure under an F6H8 tamponade which completely fills an eye with a diameter of 2.2 cm would be 0.52 mmHg. This increase in pressure is within normal diurnal pressure changes in the eye; therefore, it would seem unlikely that such an increase could cause the histological changes observed. With increasing volumes of a heavy tamponade agent, aqueous is excluded from a greater area of retina. This could account for the pathological changes reported.

Investigations on cooling with forced flow of He II. Part 2

NASA Astrophysics Data System (ADS)

Srinivasan, R.; Hofmann, A.

The measurements described in Part 1 of this Paper have been extended to a pressure of 7 bar . The value of the conductivity function, f( T), at a temperature greater than Tmax, at which it exhibits a maximum, drops rapidly with increasing pressure. Below Tmax the change in f( T) with pressure is less drastic. The Gorter-Mellink constant, AGM, increases linearly with pressure in the range 1.5-2 K and its pressure coefficient at 1 bar is 0.038 ± 0.01 per bar, independent of temperature. The superfilter is tested at 1.8 K. The flow through the superfilter is Gorter-Mellink flow. The maximum flow rate decreases as the pressure increases. The temperature distribution in the test section with and without flow is adequately described by the one-dimensional model discussed in Part 1. It is concluded that for heat transfer to He II in forced flow there is no advantage in working at pressures > 1 bar. 1 bar = 100 kPa

Update on International Space Station Nickel-Hydrogen Battery On-Orbit Performance

NASA Technical Reports Server (NTRS)

Dalton, Penni; Cohen, Fred

2003-01-01

International Space Station (ISS) Electric Power System (EPS) utilizes Nickel-Hydrogen (Ni-H2) batteries as part of its power system to store electrical energy. The batteries are charged during insolation and discharged during eclipse. The batteries are designed to operate at a 35% depth of discharge (DOD) maximum during normal operation. Thirty-eight individual pressure vessel (IPV) Ni-H2 battery cells are series-connected and packaged in an Orbital Replacement Unit (ORU). Two ORUs are series-connected utilizing a total of 76 cells, to form one battery. The ISS is the first application for low earth orbit (LEO) cycling of this quantity of series-connected cells. The P6 (Port) Integrated Equipment Assembly (IEA) containing the initial ISS high-power components was successfully launched on November 30, 2000. The IEA contains 12 Battery Subassembly ORUs (6 batteries) that provide station power during eclipse periods. This paper will discuss the battery performance data after two and a half years of cycling.

International Space Station Nickel-Hydrogen Battery On-Orbit Performance

NASA Technical Reports Server (NTRS)

Dalton, Penni; Cohen, Fred

2002-01-01

International Space Station (ISS) Electric Power System (EPS) utilizes Nickel-Hydrogen (Ni-H2) batteries as part of its power system to store electrical energy. The batteries are charged during insolation and discharged during eclipse. The batteries are designed to operate at a 35 percent depth of discharge (DOD) maximum during normal operation. Thirty-eight individual pressure vessel (IPV) Ni-H2 battery cells are series-connected and packaged in an Orbital Replacement Unit (ORU). Two ORUs are series-connected utilizing a total of 76 cells to form one battery. The ISS is the first application for low earth orbit (LEO) cycling of this quantity of series-connected cells. The P6 (Port) Integrated Equipment Assembly (IEA) containing the initial ISS high-power components was successfully launched on November 30, 2000. The IEA contains 12 Battery Subassembly ORUs (6 batteries) that provide station power during eclipse periods. This paper will discuss the battery performance data after eighteen months of cycling.

Improvement of Expansive Soils Using Chemical Stabilizers

NASA Astrophysics Data System (ADS)

Ikizler, S. B.; Senol, A.; Khosrowshahi, S. K.; Hatipoğlu, M.

2014-12-01

The aim of this study is to investigate the effect of two chemical stabilizers on the swelling potential of expansive soil. A high plasticity sodium bentonite was used as the expansive soil. The additive materials including fly ash (FA) and lime (L) were evaluated as potential stabilizers to decrease the swelling pressure of bentonite. Depending on the type of additive materials, they were blended with bentonite in different percentages to assess the optimum state and approch the maximum swell pressure reduction. According to the results of swell pressure test, both fly ash and lime reduce the swelling potential of bentonite but the maximum improvement occurs using bentonite-lime mixture while the swelling pressure reduction approaches to 49%. The results reveal a significant reduction of swelling potential of expansive soil using chemical stabilizers. Keywords: Expansive soil; swell pressure; chemical stabilization; fly ash; lime

Pressure Flammability Thresholds of Selected Aerospace Materials

NASA Technical Reports Server (NTRS)

Hirsch, David B.; Williams, James H.; Harper, Susana A.; Beeson, Harold D.; Ruff, Gary A.; Pedley, Michael D.

2010-01-01

A test program was performed to determine the highest pressure in oxygen where materials used in the planned NASA Constellation Program Orion Crew Exploration Vehicle (CEV) Crew Module (CM) would not propagate a flame if an ignition source was present. The test methodology used was similar to that previously used to determine the maximum oxygen concentration (MOC) at which self-extinguishment occurs under constant total pressure conditions. An upward limiting pressure index (ULPI) was determined, where approximately 50 percent of the materials self-extinguish in a given environment. Following this, the maximum total pressure (MTP) was identified; where all samples tested (at least five) self-extinguished following the NASA-STD-6001.A Test 1 burn length criteria. The results obtained on seven materials indicate that the non-metallic materials become flammable in oxygen between 0.4 and 0.9 psia.

Failure Mechanisms of Hollow Fiber Supported Ionic Liquid Membranes

PubMed Central

Zeh, Matthew; Wickramanayake, Shan; Hopkinson, David

2016-01-01

Hollow fiber supported ionic liquid membranes (SILMs) were tested using the bubble point method to investigate potential failure modes, including the maximum transmembrane pressure before loss of the ionic liquid from the support. Porous hollow fiber supports were fabricated with different pore morphologies using Matrimid® and Torlon® as the polymeric material and 1-hexyl-3-methylimidalzolium bis(trifluoromethylsulfonyl)imide ([C6mim][Tf2N]) as the ionic liquid (IL) component. Hollow fiber SILMs were tested for their maximum pressure before failure, with pressure applied either from the bore side or shell side. It was found that the membranes exhibited one or more of three different modes of failure when pressurized: liquid loss (occurring at the bubble point), rupture, and collapse. PMID:27023620

Noise generated by a flight weight, air flow control valve in a vertical takeoff and landing aircraft thrust vectoring system

NASA Technical Reports Server (NTRS)

Huff, Ronald G.

1989-01-01

Tests were conducted in the NASA Lewis Research Center's Powered Lift Facility to experimentally evaluate the noise generated by a flight weight, 12 in. butterfly valve installed in a proposed vertical takeoff and landing thrust vectoring system. Fluctuating pressure measurements were made in the circular duct upstream and downstream of the valve. This data report presents the results of these tests. The maximum overall sound pressure level is generated in the duct downstream of the valve and reached a value of 180 dB at a valve pressure ratio of 2.8. At the higher valve pressure ratios the spectra downstream of the valve is broad banded with its maximum at 1000 Hz.

Structural Benchmark Tests of Composite Combustion Chamber Support Completed

NASA Technical Reports Server (NTRS)

Krause, David L.; Thesken, John C.; Shin, E. Eugene; Sutter, James K.

2005-01-01

A series of mechanical load tests was completed on several novel design concepts for extremely lightweight combustion chamber support structures at the NASA Glenn Research Center (http://www.nasa.gov/glenn/). The tests included compliance evaluation, preliminary proof loadings, high-strain cyclic testing, and finally residual strength testing of each design (see the photograph on the left). Loads were applied with single rollers (see the photograph on the right) or pressure plates (not shown) located midspan on each side to minimize the influence of contact stresses on corner deformation measurements. Where rollers alone were used, a more severe structural loading was produced than the corresponding equal-force pressure loading: the maximum transverse shear force existed over the entire length of each side, and the corner bending moments were greater than for a distributed (pressure) loading. Failure modes initiating at the corner only provided a qualitative indication of the performance limitations since the stress state was not identical to internal pressure. Configurations were tested at both room and elevated temperatures. Experimental results were used to evaluate analytical prediction tools and finite-element methodologies for future work, and they were essential to provide insight into the deformation at the corners. The tests also were used to assess fabrication and bonding details for the complicated structures. They will be used to further optimize the design of the support structures for weight performance and the efficacy of corner reinforcement.

Effect of initial moisture content on the in-vessel composting under air pressure of organic fraction of municipal solid waste in Morocco

PubMed Central

2013-01-01

This study aimed to evaluate the effect of initial moisture content on the in-vessel composting under air pressure of organic fraction of municipal solid waste in Morocco in terms of internal temperature, produced gases quantity, organic matter conversion rate, and the quality of the final composts. For this purpose, in-vessel bioreactor was designed and used to evaluate both appropriate initial air pressure and appropriate initial moisture content for the composting process. Moreover, 5 experiments were carried out within initial moisture content of 55%, 65%, 70%, 75% and 85%. The initial air pressure and the initial moisture content of the mixture showed a significant effect on the aerobic composting. The experimental results demonstrated that for composting organic waste, relatively high moisture contents are better at achieving higher temperatures and retaining them for longer times. This study suggested that an initial moisture content of around 75%, under 0.6 bar, can be considered as being suitable for efficient composting of organic fraction of municipal solid waste. These last conditions, allowed maximum value of temperature and final composting product with good physicochemical properties as well as higher organic matter degradation and higher gas production. Moreover, final compost obtained showed good maturity levels and can be used for agricultural applications. PMID:23369502

Finite Element Analysis of Patella Alta: A Patellofemoral Instability Model.

PubMed

Watson, Nicole A; Duchman, Kyle R; Grosland, Nicole M; Bollier, Matthew J

2017-01-01

This study aims to provide biomechanical data on the effect of patella height in the setting of medial patellofemoral ligament (MPFL) reconstruction using finite element analysis. The study will also examine patellofemoral joint biomechanics using variable femoral insertion sites for MPFL reconstruction. A previously validated finite element knee model was modified to study patella alta and baja by translating the patella a given distance to achieve each patella height ratio. Additionally, the models were modified to study various femoral insertion sites of the MPFL (anatomic, anterior, proximal, and distal) for each patella height model, resulting in 32 unique scenarios available for investigation. In the setting of patella alta, the patellofemoral contact area decreased, resulting in a subsequent increase in maximum patellofemoral contact pressures as compared to the scenarios with normal patellar height. Additionally, patella alta resulted in decreased lateral restraining forces in the native knee scenario as well as following MPFL reconstruction. Changing femoral insertion sites had a variable effect on patellofemoral contact pressures; however, distal and anterior femoral tunnel malpositioning in the setting of patella alta resulted in grossly elevated maximum patellofemoral contact pressures as compared to other scenarios. Patella alta after MPFL reconstruction results in decreased lateral restraining forces and patellofemoral contact area and increased maximum patellofemoral contact pressures. When the femoral MPFL tunnel is malpositioned anteriorly or distally on the femur, the maximum patellofemoral contact pressures increase with severity of patella alta. When evaluating patients with patellofemoral instability, it is important to recognize patella alta as a potential aggravating factor. Failure to address patella alta in the setting of MPFL femoral tunnel malposition may result in even further increases in patellofemoral contact pressures, making it essential to optimize intraoperative techniques to confirm anatomic MPFL femoral tunnel positioning.

Finite Element Analysis of Patella Alta: A Patellofemoral Instability Model

PubMed Central

Duchman, Kyle R.; Grosland, Nicole M.; Bollier, Matthew J.

2017-01-01

Abstract Background: This study aims to provide biomechanical data on the effect of patella height in the setting of medial patellofemoral ligament (MPFL) reconstruction using finite element analysis. The study will also examine patellofemoral joint biomechanics using variable femoral insertion sites for MPFL reconstruction. Methods: A previously validated finite element knee model was modified to study patella alta and baja by translating the patella a given distance to achieve each patella height ratio. Additionally, the models were modified to study various femoral insertion sites of the MPFL (anatomic, anterior, proximal, and distal) for each patella height model, resulting in 32 unique scenarios available for investigation. Results: In the setting of patella alta, the patellofemoral contact area decreased, resulting in a subsequent increase in maximum patellofemoral contact pressures as compared to the scenarios with normal patellar height. Additionally, patella alta resulted in decreased lateral restraining forces in the native knee scenario as well as following MPFL reconstruction. Changing femoral insertion sites had a variable effect on patellofemoral contact pressures; however, distal and anterior femoral tunnel malpositioning in the setting of patella alta resulted in grossly elevated maximum patellofemoral contact pressures as compared to other scenarios. Conclusions: Patella alta after MPFL reconstruction results in decreased lateral restraining forces and patellofemoral contact area and increased maximum patellofemoral contact pressures. When the femoral MPFL tunnel is malpositioned anteriorly or distally on the femur, the maximum patellofemoral contact pressures increase with severity of patella alta. Clinical Relevance: When evaluating patients with patellofemoral instability, it is important to recognize patella alta as a potential aggravating factor. Failure to address patella alta in the setting of MPFL femoral tunnel malposition may result in even further increases in patellofemoral contact pressures, making it essential to optimize intraoperative techniques to confirm anatomic MPFL femoral tunnel positioning. PMID:28852343

Users manual for updated computer code for axial-flow compressor conceptual design

NASA Technical Reports Server (NTRS)

Glassman, Arthur J.

1992-01-01

An existing computer code that determines the flow path for an axial-flow compressor either for a given number of stages or for a given overall pressure ratio was modified for use in air-breathing engine conceptual design studies. This code uses a rapid approximate design methodology that is based on isentropic simple radial equilibrium. Calculations are performed at constant-span-fraction locations from tip to hub. Energy addition per stage is controlled by specifying the maximum allowable values for several aerodynamic design parameters. New modeling was introduced to the code to overcome perceived limitations. Specific changes included variable rather than constant tip radius, flow path inclination added to the continuity equation, input of mass flow rate directly rather than indirectly as inlet axial velocity, solution for the exact value of overall pressure ratio rather than for any value that met or exceeded it, and internal computation of efficiency rather than the use of input values. The modified code was shown to be capable of computing efficiencies that are compatible with those of five multistage compressors and one fan that were tested experimentally. This report serves as a users manual for the revised code, Compressor Spanline Analysis (CSPAN). The modeling modifications, including two internal loss correlations, are presented. Program input and output are described. A sample case for a multistage compressor is included.

Intradetrusor onabotulinumtoxinA injections for refractory neurogenic detrusor overactivity incontinence: do we need urodynamic investigation for outcome assessment?

PubMed

Koschorke, Miriam; Leitner, Lorenz; Sadri, Helen; Knüpfer, Stephanie C; Mehnert, Ulrich; Kessler, Thomas M

2017-12-01

To evaluate if urinary continence in patients with refractory neurogenic detrusor overactivity (NDO) incontinence after intradetrusor onabotulinumtoxinA injections is sufficient for appropriate outcome assessment or if urodynamic investigation (UDI) is needed. A consecutive series of 148 patients undergoing intradetrusor onabotulinumtoxinA injections for refractory NDO incontinence were prospectively evaluated. Patients underwent UDI before and at 6 weeks after onabotulinumtoxinA injections. The primary outcome was the prevalence of maximum storage detrusor pressure (Pdet max storage) of >40 cmH 2 O in continent patients at 6 weeks after treatment. The secondary outcomes were treatment effects on other clinical and video-urodynamic variables. At 6 weeks after intradetrusor onabotulinumtoxinA injections, 98 of the 148 patients (66%) with NDO incontinence were continent. Of these patients, 18 (18%, confidence interval 12-27%) had a Pdet max storage of >40 cmH 2 O. Gender, underlying neurological disorder, and high Pdet max storage before treatment appear to increase the risk of poor urodynamic outcomes. Urinary continence is not sufficient for outcome assessment after intradetrusor onabotulinumtoxinA injections, as high intravesical pressures threatening the upper urinary tract may be missed in a relevant proportion of continent patients. Therefore, we strongly recommend UDI as a routine part of the follow-up. © 2017 The Authors BJU International © 2017 BJU International Published by John Wiley & Sons Ltd.

Generation of subnanosecond electron beams in air at atmospheric pressure

NASA Astrophysics Data System (ADS)

Kostyrya, I. D.; Tarasenko, V. F.; Baksht, E. Kh.; Burachenko, A. G.; Lomaev, M. I.; Rybka, D. V.

2009-11-01

Optimum conditions for the generation of runaway electron beams with maximum current amplitudes and densities in nanosecond pulsed discharges in air at atmospheric pressure are determined. A supershort avalanche electron beam (SAEB) with a current amplitude of ˜30 A, a current density of ˜20 A/cm2, and a pulse full width at half maximum (FWHM) of ˜100 ps has been observed behind the output foil of an air-filled diode. It is shown that the position of the SAEB current maximum relative to the voltage pulse front exhibits a time shift that varies when the small-size collector is moved over the foil surface.

Causes and Control of Corrosion in Buried-Conduit Heat Distribution Systems

DTIC Science & Technology

1991-07-01

rubber , and foamed plastics such as polyurethanic anld phenolic) nominally contain 10 to 500 ppmn soluble chloide.’ Further, insulation can also become...pressure ratings. A maximum P X T limitation exists for all gasket materials. For example, the maximum temperature and pressure ratings for an EPDM ...ethylene propylene diene monomer) rubber material are, respectively, 3() ’F and 150 psi. The material, however, cannot be expected to perform

Vocal warm-up increases phonation threshold pressure in soprano singers at high pitch.

PubMed

Motel, Tamara; Fisher, Kimberly V; Leydon, Ciara

2003-06-01

Vocal warm-up is thought to optimize singing performance. We compared effects of short-term, submaximal, vocal warm-up exercise with those of vocal rest on the soprano voice (n = 10, ages 19-21 years). Dependent variables were the minimum subglottic air pressure required for vocal fold oscillation to occur (phonation threshold pressure, Pth), and the maximum and minimum phonation fundamental frequency. Warm-up increased Pth for high pitch phonation (p = 0.033), but not for comfortable (p = 0.297) or low (p = 0.087) pitch phonation. No significant difference in the maximum phonation frequency (p = 0.193) or minimum frequency (p = 0.222) was observed. An elevated Pth at controlled high pitch, but an unchanging maximum and minimum frequency production suggests that short-term vocal exercise may increase the viscosity of the vocal fold and thus serve to stabilize the high voice.

Nitrogen nucleation in a cryogenic supersonic nozzle

NASA Astrophysics Data System (ADS)

Bhabhe, Ashutosh; Wyslouzil, Barbara

2011-12-01

We follow the vapor-liquid phase transition of N2 in a cryogenic supersonic nozzle apparatus using static pressure measurements. Under our operating conditions, condensation always occurs well below the triple point. Mean field kinetic nucleation theory (MKNT) does a better job of predicting the conditions corresponding to the estimated maximum nucleation rates, Jmax = 1017±1 cm-3 s-1, than two variants of classical nucleation theory. Combining the current results with the nucleation pulse chamber measurements of Iland et al. [J. Chem. Phys. 130, 114508-1 (2009)], we use nucleation theorems to estimate the critical cluster properties. Both the theories overestimate the size of the critical cluster, but MKNT does a good job of estimating the excess internal energy of the clusters.

49 CFR 173.337 - Nitric oxide.

Code of Federal Regulations, 2010 CFR

2010-10-01

... charged to a pressure of not more than 5,170 kPa (750 psi) at 21 °C (70 °F). Transportation of nitric... with a minimum test pressure of 200 bar. The maximum working pressure of the cylinder must not exceed 50 bar. The pressure in the cylinder at 65 °C (149 °F) may not exceed the test pressure. The use of...

49 CFR 173.337 - Nitric oxide.

Code of Federal Regulations, 2014 CFR

2014-10-01

... charged to a pressure of not more than 5,170 kPa (750 psi) at 21 °C (70 °F). Transportation of nitric... with a minimum test pressure of 200 bar. The maximum working pressure of the cylinder must not exceed 50 bar. The pressure in the cylinder at 65 °C (149 °F) may not exceed the test pressure. The use of...

49 CFR 173.337 - Nitric oxide.

Code of Federal Regulations, 2011 CFR

2011-10-01

... charged to a pressure of not more than 5,170 kPa (750 psi) at 21 °C (70 °F). Transportation of nitric... with a minimum test pressure of 200 bar. The maximum working pressure of the cylinder must not exceed 50 bar. The pressure in the cylinder at 65 °C (149 °F) may not exceed the test pressure. The use of...

49 CFR 173.337 - Nitric oxide.

Code of Federal Regulations, 2012 CFR

2012-10-01

... charged to a pressure of not more than 5,170 kPa (750 psi) at 21 °C (70 °F). Transportation of nitric... with a minimum test pressure of 200 bar. The maximum working pressure of the cylinder must not exceed 50 bar. The pressure in the cylinder at 65 °C (149 °F) may not exceed the test pressure. The use of...

49 CFR 173.337 - Nitric oxide.

Code of Federal Regulations, 2013 CFR

2013-10-01

... charged to a pressure of not more than 5,170 kPa (750 psi) at 21 °C (70 °F). Transportation of nitric... with a minimum test pressure of 200 bar. The maximum working pressure of the cylinder must not exceed 50 bar. The pressure in the cylinder at 65 °C (149 °F) may not exceed the test pressure. The use of...

Space shuttle solid rocket booster water entry cavity collapse loads

NASA Technical Reports Server (NTRS)

Keefe, R. T.; Rawls, E. A.; Kross, D. A.

1982-01-01

Solid rocket booster cavity collapse flight measurements included external pressures on the motor case and aft skirt, internal motor case pressures, accelerometers located in the forward skirt, mid-body area, and aft skirt, as well as strain gages located on the skin of the motor case. This flight data yielded applied pressure longitudinal and circumferential distributions which compare well with model test predictions. The internal motor case ullage pressure, which is below atmospheric due to the rapid cooling of the hot internal gas, was more severe (lower) than anticipated due to the ullage gas being hotter than predicted. The structural dynamic response characteristics were as expected. Structural ring and wall damage are detailed and are considered to be attributable to the direct application of cavity collapse pressure combined with the structurally destabilizing, low internal motor case pressure.

40 CFR 63.9921 - What are the installation, operation and maintenance requirements for my monitors?

Code of Federal Regulations, 2011 CFR

2011-07-01

...) For the pressure drop CPMS, you must: (i) Locate the pressure sensor(s) in or as close to a position... calibration quarterly and transducer calibration monthly. (v) Conduct calibration checks any time the sensor exceeds the manufacturer's specified maximum operating pressure range, or install a new pressure sensor...

40 CFR 63.9921 - What are the installation, operation and maintenance requirements for my monitors?

Code of Federal Regulations, 2014 CFR

2014-07-01

...) For the pressure drop CPMS, you must: (i) Locate the pressure sensor(s) in or as close to a position... calibration quarterly and transducer calibration monthly. (v) Conduct calibration checks any time the sensor exceeds the manufacturer's specified maximum operating pressure range, or install a new pressure sensor...

40 CFR 63.9921 - What are the installation, operation and maintenance requirements for my monitors?

Code of Federal Regulations, 2012 CFR

2012-07-01

...) For the pressure drop CPMS, you must: (i) Locate the pressure sensor(s) in or as close to a position... calibration quarterly and transducer calibration monthly. (v) Conduct calibration checks any time the sensor exceeds the manufacturer's specified maximum operating pressure range, or install a new pressure sensor...

40 CFR 63.9921 - What are the installation, operation and maintenance requirements for my monitors?

Code of Federal Regulations, 2013 CFR

2013-07-01

...) For the pressure drop CPMS, you must: (i) Locate the pressure sensor(s) in or as close to a position... calibration quarterly and transducer calibration monthly. (v) Conduct calibration checks any time the sensor exceeds the manufacturer's specified maximum operating pressure range, or install a new pressure sensor...

Effects of press sizes on internal steam pressure during particleboard hot-pressing process

Treesearch

Zhiyong Cai; Michael Birkeland; James M. Wescott; Jane O' Dell; Jerrold E. Winandy

2009-01-01

Internal steam pressure produced during the hot-pressing cycle in particleboard production is critical to the newly developed bond strength that will determine the overall performance of particleboard. The difference between the accumulation of internal steam pressure for small panels made in the laboratory and that of large commercial-sized panels makes it difficult...

Role of organic matter on aggregate stability and related mechanisms through organic amendments

NASA Astrophysics Data System (ADS)

Zaher, Hafida

2010-05-01

To date, only a few studies have tried to simultaneously compare the role of neutral and uronic sugars and lipids on soil structural stability. Moreover, evidence for the mechanisms involved has often been established following wetting of moist aggregates after various pre-treatments thus altering aggregate structure and resulting in manipulations on altered aggregates on which the rapid wetting process may not be involved anymore. To the best of our knowledge, the objective of this work was to study the role of neutral and uronic sugars and lipids in affecting key mechanisms (swelling rate, pressure evolution) involved in the stabilization of soil structure. A long-term incubation study (48-wk) was performed on a clay loam and a silty-clay loam amended with de-inking-secondary sludge mix at three rates (8, 16 and 24 Mg dry matter ha-1), primary-secondary sludge mix at one rate (18 Mg oven-dry ha-1) and composted de-inking sludge at one rate (24 Mg ha-1). Different structural stability indices (stability of moist and dry aggregates, the amount of dispersible clay and loss of soil material following sudden wetting) were measured on a regular basis during the incubation, along with CO2 evolved, neutral and uronic sugar, and lipid contents. During the course of the incubations, significant increases in all stability indices were measured for both soil types. In general, the improvements in stability were proportional to the amount of C added as organic amendments. These improvements were linked to a very intense phase of C mineralization and associated with increases in neutral and uronic sugars as well as lipid contents. The statistical relationships found between the different carbonaceous fractions and stability indices were all highly significant and indicated no clear superiority of one fraction over another. Paper sludge amendments also resulted in significant decreases in maximum internal pressure of aggregate and aggregate swelling following immersion in water, two mechanisms affecting structural stability. Overall, the results suggest that reduction in maximum internal pressure induced by organic amendments most likely resulted from increases in pore surface roughness and pore occlusion rather than by increase in surface wetting angles. This study also supports the view of a non specific action of the lipids, neutral and uronic sugars on aggregate stability to rapid wetting. Key words: soil aggregate stability, polysaccharides, lipids, mechanisms, organic matter

Novel Techniques for High Pressure Falling Sphere Viscosimetry under Simulated Earth's Mantle Conditions

NASA Astrophysics Data System (ADS)

Mueller, H. J.; Beckmann, F.; Dobson, D. P.; Hunt, S. A.; Secco, R.; Lauterjung, J.; Lathe, C.

2014-12-01

Viscosity data of melts measured under in situ high pressure conditions are crucial for the understanding of Earth's lower mantle and the interior of terrestrial and extrasolar Super-Earth planets. We report recent technical advances and techniques enabling falling sphere viscosity measurements in single- and double-stage DIA-type multi-anvil apparatus. For the experiments we used presses with a maximum load of 250 tons and 1750 tons. We anticipate that our system will enable viscosity measurements up to the maximum pressure for non-diamond anvils, i.e. pressures up to some 30 GPa. For the development of the new set ups the deformation of the cell assemblies were analyzed by X-ray absorption tomography at beamline W II at DESY/HASYLAB after the high pressure runs. These analysis gave considerable insights into strategies for improving the cell assembly with the result that the optimized assemblies could be used at much higher pressures without blow-outs. We think this approach is much faster and more beneficial than the classical way of trial and error. Additionally to prevent high pressure blow outs the task was to make the whole melting chamber accessible for the high pressure X-radiography system up to the maximum pressures. This way the accuracy and reliability of the measurements can be improved. For this goal we used X-ray transparent cBN-anvils at the single-stage DIA large volume press. Because this material is recently not available for the cube size of 32 mm this aproach did not work for the double-stage DIA. As a very useful and economical alternative we used slotted carbide anvils filled with fired pyrophyllite bars. To improve the frame quality of the platinum spheres taken by the CCD-camera the energy of the monochromatic X-rays had to be increased to 100 keV. The resulting ascent of scattered radiation required a new design of the X-radiography unit. Our results are demonstrated with viscosity measurements following Stokes law by evaluation of X-radiography sequences taken by a CCD-camera at pressures of 5 GPa as well as 10 GPa and temperatures of 1890 K. As the first result we could increase the maximum pressure range of published viscosity measurements with dacite melts by almost factor 1.5 (see Tinker et al., 2004).

Maximum Expected Wall Heat Flux and Maximum Pressure After Sudden Loss of Vacuum Insulation on the Stratospheric Observatory for Infrared Astronomy (SOFIA) Liquid Helium (LHe) Dewars

NASA Technical Reports Server (NTRS)

Ungar, Eugene K.

2014-01-01

The aircraft-based Stratospheric Observatory for Infrared Astronomy (SOFIA) is a platform for multiple infrared observation experiments. The experiments carry sensors cooled to liquid helium (LHe) temperatures. A question arose regarding the heat input and peak pressure that would result from a sudden loss of the dewar vacuum insulation. Owing to concerns about the adequacy of dewar pressure relief in the event of a sudden loss of the dewar vacuum insulation, the SOFIA Program engaged the NASA Engineering and Safety Center (NESC). This report summarizes and assesses the experiments that have been performed to measure the heat flux into LHe dewars following a sudden vacuum insulation failure, describes the physical limits of heat input to the dewar, and provides an NESC recommendation for the wall heat flux that should be used to assess the sudden loss of vacuum insulation case. This report also assesses the methodology used by the SOFIA Program to predict the maximum pressure that would occur following a loss of vacuum event.

Volumetric velocity measurements in restricted geometries using spiral sampling: a phantom study.

PubMed

Nilsson, Anders; Revstedt, Johan; Heiberg, Einar; Ståhlberg, Freddy; Bloch, Karin Markenroth

2015-04-01

The aim of this study was to evaluate the accuracy of maximum velocity measurements using volumetric phase-contrast imaging with spiral readouts in a stenotic flow phantom. In a phantom model, maximum velocity, flow, pressure gradient, and streamline visualizations were evaluated using volumetric phase-contrast magnetic resonance imaging (MRI) with velocity encoding in one (extending on current clinical practice) and three directions (for characterization of the flow field) using spiral readouts. Results of maximum velocity and pressure drop were compared to computational fluid dynamics (CFD) simulations, as well as corresponding low-echo-time (TE) Cartesian data. Flow was compared to 2D through-plane phase contrast (PC) upstream from the restriction. Results obtained with 3D through-plane PC as well as 4D PC at shortest TE using a spiral readout showed excellent agreements with the maximum velocity values obtained with CFD (<1 % for both methods), while larger deviations were seen using Cartesian readouts (-2.3 and 13 %, respectively). Peak pressure drop calculations from 3D through-plane PC and 4D PC spiral sequences were respectively 14 and 13 % overestimated compared to CFD. Identification of the maximum velocity location, as well as the accurate velocity quantification can be obtained in stenotic regions using short-TE spiral volumetric PC imaging.

49 CFR 192.328 - Additional construction requirements for steel pipe using alternative maximum allowable operating...

Code of Federal Regulations, 2012 CFR

2012-10-01

... 49 Transportation 3 2012-10-01 2012-10-01 false Additional construction requirements for steel pipe using alternative maximum allowable operating pressure. 192.328 Section 192.328 Transportation... Lines and Mains § 192.328 Additional construction requirements for steel pipe using alternative maximum...

49 CFR 192.328 - Additional construction requirements for steel pipe using alternative maximum allowable operating...

Code of Federal Regulations, 2014 CFR

2014-10-01

... 49 Transportation 3 2014-10-01 2014-10-01 false Additional construction requirements for steel pipe using alternative maximum allowable operating pressure. 192.328 Section 192.328 Transportation... Lines and Mains § 192.328 Additional construction requirements for steel pipe using alternative maximum...

An experimental study of the influence of stress history on fault slip during injection of supercritical CO2

NASA Astrophysics Data System (ADS)

Cuss, Robert J.; Wiseall, Andrew C.; Tamayo-Mas, Elena; Harrington, Jon F.

2018-04-01

The injection of super-critical CO2 into a depleted reservoir will alter the pore pressure of the basin, which if sufficiently perturbed could result in fault slip. Therefore, knowledge of the acceptable pressure limits is required in order to maintain fault stability. A two-part laboratory study was conducted on fully saturated kaolinite fault gouge to investigate this issue. Previously, we showed that fault slip occurred once pore-pressure within the gouge was sufficient to overcome the normal stress acting on the fault. For kaolinite, this behaviour occurred at a pressure similar to the yield stress. The current study shows that following a slow-reduction in the maximum principal stress, as would be expected through changes in effective stress, the reactivation pressure shows a stress memory. Consequently, the pressure necessary to initiate fault slip is similar to that required at the maximum stress encountered. Therefore, fault slip is at least partially controlled by the previous maximum stress and not the current stress state. During the slow reduction in normal stress, the flow characteristics of the fault remain unchanged until pore-pressure exceeds shear stress and does not increase significantly until it exceeds normal stress. This results in fault slip, which slows the rate of flow increase as shear is an effective self-sealing mechanism. These observations lead to the conclusion that stress history is a vital parameter when considering fault stability.

Surface magnetometer experiments - Internal lunar properties

NASA Technical Reports Server (NTRS)

Dyal, P.; Daily, W. D.; Parkin, C. W.

1973-01-01

Magnetic fields have been measured on the lunar surface at the Apollo 12, 14, 15, and 16 landing sites. The remanent field values at these sites are respectively 38, 103 (maximum), 3, and 327 gamma (maximum). Simultaneous magnetic field and solar plasma pressure measurements show that the remanent fields at the Apollo 12 and 16 sites are compressed and that the scale size of the Apollo 16 remanent field is 5 less than or equal to L less than 100 km. The global eddy current fields, induced by magnetic step transients in the solar wind, have been analyzed to calculate an electrical conductivity profile. From nightside data it has been found that deeper than 170 km into the moon, the conductivity rises from .0003 mho/m to .01 mho/m at 1000 km depth. Analysis of dayside transient data using a spherically symmetric two-layer model yields a homogeneous conducting core with a radius equal to 0.9 lunar radius and a conductivity of .001 mho/m, surrounded by a nonconducting shell of thickness equal to 0.1 lunar radius.

Modeling and testing of a knitted-sleeve fluidic artificial muscle

NASA Astrophysics Data System (ADS)

Ball, Erick J.; Meller, Michael A.; Chipka, Jordan B.; Garcia, Ephrahim

2016-11-01

The knitted-sleeve fluidic muscle is similar in design to a traditional McKibben muscle, with a separate bladder and sleeve. However, in place of a braided sleeve, it uses a tubular-knit sleeve made from a thin strand of flexible but inextensible yarn. When the bladder is pressurized, the sleeve expands by letting the loops of fiber slide past each other, changing the dimensions of the rectangular cells in the stitch pattern. Ideally, the internal volume of the sleeve would reach a maximum when its length has contracted by 2/3 from its maximum length, and although this is not reachable in practice, preliminary tests show that free contraction greater than 50% is achievable. The motion relies on using a fiber with a low coefficient of friction in order to reduce hysteresis to an acceptable level. In addition to increased stroke length, potential advantages of this technique include slower force drop-off during the stroke, more useable energy in certain applications, and greater similarity to the force-length relationship of skeletal muscle. Its main limitation is its potentially greater effect from friction compared to other fluidic muscle designs.

Tectonic overpressure may reconcile the structural and petrological records of the Adula nappe (Central Alps)

NASA Astrophysics Data System (ADS)

Pleuger, Jan; Podladchikov, Yuri

2014-05-01

The Penninic Alps are the result of progressive underthrusting of oceanic and continental domains below the Adriatic microplate. Situated in the internal part of the Alpine orogen, they expose basement and thinned cover nappes which have been metamorphosed to variable degree, among them several units which were subjected to ultrahigh-pressure metamorphism. Due to the more or less strong nappe-internal deformation of these units, cross sections through the Penninic Alps cannot be restored kinematically by area or line balancing techniques. Instead, such restorations attempt to consistently reconcile geochronological and structural data and petrological pressure-temperature estimates. Pressure data are usually converted into depth assuming that they were lithostatic which puts the ultrahigh-pressure units to subcrustal depths. Tectonic exhumation of a unit from such a depth by whatever mechanism requires a large-scale normal fault with several tens of kilometres of displacement in the hanging wall of the unit. However, for all Penninic ultrahigh-pressure units (Dora Maira unit, Zermatt-Saas zone, Monviso unit, Adula-Cima Lunga nappe), the oldest mappable post-peak-pressure structures are related to top-to-the-foreland shearing, i.e. thrusting. There are two potential solutions to this dilemma. The first one is that either the exhumation was indeed accommodated by a large-scale normal fault which became completely overprinted during later deformational stages. The other one is that peak pressures were not lithostatic. To our knowledge, the first solution is applied to all kinematic models of the Alps so far. In order to explore the feasibility of the second solution, we performed a purely structural restoration of the NFP20-East cross section without lithostatic pressure-to-depth-conversions. This cross-section comprises the ultrahigh-pressure Adula nappe (up to ca. 30 kbar) and relies on quantitative strain data from the overlying units. The result shows that, in accordance with the structural record, the Adula nappe can be restored to maximum depths of up to ca. 60 km. For individual points of the Adula nappe in the restored cross section, corresponding to the sporadic occurences of (ultra)high-pressure rocks, lithostatic pressures are exceeded by petrological peak-pressure data by about 40% to 80%. Such amounts of tectonic overpressure are within the limits of theoretical considerations and numerical modelling results. For the other units comprised in the cross section, and for subsequent tectono-metamorphic stages of the Adula nappe, negligible amounts of overpressure (around 10%) are determined from the restoration. We conclude that (1) the NFP20-East cross section can be kinematically restored by using only structural data, (2) the dilemma mentioned above can be solved by admitting realisting amounts of tectonic overpressure, and (3) significant amounts of overpressure were established only locally and episodically.

The association of remotely-sensed outdoor temperature with blood pressure levels in REGARDS: a cross-sectional study of a large, national cohort of African-American and white participants

PubMed Central

2011-01-01

Background Evidence is mounting regarding the clinically significant effect of temperature on blood pressure. Methods In this cross-sectional study the authors obtained minimum and maximum temperatures and their respective previous week variances at the geographic locations of the self-reported residences of 26,018 participants from a national cohort of blacks and whites, aged 45+. Linear regression of data from 20,623 participants was used in final multivariable models to determine if these temperature measures were associated with levels of systolic or diastolic blood pressure, and whether these relations were modified by stroke-risk region, race, education, income, sex hypertensive medication status, or age. Results After adjustment for confounders, same-day maximum temperatures 20°F lower had significant associations with 1.4 mmHg (95% CI: 1.0, 1.9) higher systolic and 0.5 mmHg (95% CI: 0.3, 0.8) higher diastolic blood pressures. Same-day minimum temperatures 20°F lower had a significant association with 0.7 mmHg (95% CI: 0.3, 1.0) higher systolic blood pressures but no significant association with diastolic blood pressure differences. Maximum and minimum previous-week temperature variabilities showed significant but weak relationships with blood pressures. Parameter estimates showed effect modification of negligible magnitude. Conclusions This study found significant associations between outdoor temperature and blood pressure levels, which remained after adjustment for various confounders including season. This relationship showed negligible effect modification. PMID:21247466

Study on turbulent flow and heat transfer performance of tubes with internal fins in EGR cooler

NASA Astrophysics Data System (ADS)

Liu, Lin; Ling, Xiang; Peng, Hao

2015-07-01

In this paper, flow and heat transfer performances of the tubes with internal longitudinal fins in Exhaust Gas Recirculation (EGR ) cooler were investigated by three-dimension computation and experiment . Each test tube was a single-pipe structure, without inner tube. Three-dimension computation was performed to determine the thermal characteristics difference between the two kinds of tubes, that is, the tube with an inner solid staff as a blocked structure and the tube without the blocked structure. The effects of fin width and fin height on heat transfer and flow are examined. For proving the validity of numerical method, the calculated results were compared with corresponding experimental data. The tube-side friction factor and heat transfer coefficient were examined. As a result, the maximum deviations between the numerical results and the experimental data are approximately 5.4 % for friction factor and 8.6 % for heat transfer coefficient, respectively. It is found that two types of internally finned tubes enhance significantly heat transfer. The heat transfer of the tube with blocked structure is better, while the pressure drop of the tube without blocked structure is lower. The comprehensive performance of the unblocked tube is better to applied in EGR cooler.

Radiative signals from impact of Shoemaker-Levy on Jupiter

NASA Technical Reports Server (NTRS)

Ahrens, Thomas J.; Orton, Glenn S.; Takata, Toshiko; Okeefe, John D.

1994-01-01

The temperature and internal energy fields calculated by Takata et al. in the plume are used to calculate the greybody thermal radiation emitted versus wavelength to predict what might be observed by several spectral sensors operating from different platforms when fragments of Comet Shoemaker-Levy 9 (SL-9) impact Jupiter in July 1994. A SPH code was used by Takata et al. to calculate the full three dimensional flow and thermodynamic fields in the comet fragment and the atmosphere of Jupiter. We determined the fragment penetration depth, energy partitioning between the atmosphere and the impactor, and energy density deposited per unit length over the trajectory. Once the impactor had disintegrated and stopped, and the strong atmospheric shock decayed, the flow is driven by buoyancy effects. We then used our SPH code to calculate the flow and thermodynamic fields: pressure, article velocity, temperature, and internal energy distributions in the plume. The calculations for 2 and 10 km cometary fragments yield maximum deposition depths of approximately 175 and 525 km, respectively (1 bar = 0 km depth). We also calculated that 0.7 and 0.6 of the initial kinetic energy of the 10 and 2 km bolides, respectively, are deposited as internal energy in Jupiter's atmosphere.

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.

The Optimal Forest Rotation: A Discussion and Annotated Bibliography

Treesearch

David H. Newman

1988-01-01

The literature contains six different criteria of the optimal forest rotation: (1) maximum single-rotation physical yield, (2) maximum single-rotation annual yield, (3) maximum single-rotation discounted net revenues, (4) maximum discounted net revenues from an infinite series of rotations, (5) maximum annual net revenues, and (6) maximum internal rate of return. First...

A new restoration of the NFP20-East cross section and possible tectonic overpressure in the Penninic Adula Nappe (Central Alps)

NASA Astrophysics Data System (ADS)

Pleuger, J.; Podladchikov, Y.

2012-04-01

The Adula Nappe in the eastern Central Alps is one of the four units in the Alps from which ultrahigh-pressure rocks have been reported. Several very different models for its tectonic history have been published but none of these models is fully satisfactory. In the models of Schmid et al. (1996) and Engi et al. (2001), the main mechanism of exhumation is assumed to be extrusion. The extrusion models require top-to-the-hinterland, i.e. top-to-the-south faulting in the hanging wall of the exhuming nappe for which there is no evidence. Froitzheim et al. (2003) proposed a scenario with two different subduction zones, an internal one in which the South Penninic and Briançonnais domains were subducted, and an external one in which the North Penninc domain and the European margin, including the Adula nappe, were subducted. In this model, the exhumation of the Adula nappe results from the subduction of the overlying sub-Briançonnais and sub-South-Penninic mantle in the internal subduction zone. The Adula nappe would then have been exhumed from below into a top-to-the-north shear zone also affecting the overriding Briançonnais units. The main shortcoming of this model is that otherwise there is little evidence for two Alpine subduction zones. All the models cited above are based on the conversion of peak pressures obtained from geobarometry to depth by assuming lithostatic pressures. This results in a much greater burial depth of the Adula Nappe with respect to the surrounding units which poses major problems when trying to reconcile maximum burial depths of the Penninic nappes with their structural record. We performed a new restoration of the NFP20-East cross section (Schmid et al. 1996) without applying a lithostatic pressure-to-depth conversion but a purely geometrical restoration of deformation events in the Penninic nappe stack. The major constraints on these reconstructions are given by strain estimates for the major deformation phases in the units overlying the Adula Nappe (Mayerat Demarne 1994) and zircon fission track ages (Flisch 1986) indicating that the Austroalpine units have not been more than 10 km below surface after the Palaeocene. The maximum pressures of eclogites from the Adula nappe reported in the literature are about 1.8 times as high as the lithostatic pressures derived from our cross section restoration. Given that tectonic overpressure in an orogen may be as high as lithostatic pressure (Petrini and Podladchikov 2000), the results of our cross section restoration suggest that the exceptionally high pressures recorded by the Adula Nappe may not be due to exceptionally deep burial but, at least partly, to tectonic overpressure. Engi, M., Berger, A. & Roselle, G.T. 2001: Geology 29, 1143-1146. Flisch, M. 1986: Bull. Ver. Schweiz. Pet.-Geol.-Ing. 53, 23- 49. Froitzheim, N., Pleuger, J., Roller, S. & Nagel, T. 2003: Geology 31, 925-928. Mayerat Demarne, A.M. 1994: Beitr. Geol. Karte Schweiz, 165. Petrini, K. & Podladchikov, Yu. 2000: J. metamorphic Geol.18, 67-77. Schmid, S.M., Pfiffner, O.A., Froitzheim, N., Schönborn, G. & Kissling, E. 1996: Tectonics 15, 1036-1064.

Hereditary internal anal sphincter myopathy causing proctalgia fugax and constipation. A newly identified condition.

PubMed

Kamm, M A; Hoyle, C H; Burleigh, D E; Law, P J; Swash, M; Martin, J E; Nicholls, R J; Northover, J M

1991-03-01

A newly identified myopathy of the internal anal sphincter is described. In the affected family, at least one member from each of five generations had severe proctalgia fugax; onset was usually in the third to fifth decades of life. Three members of the family have been studied in detail. Each had severe pain intermittently during the day and hourly during the night. Constipation was an associated symptom, in particular difficulty with rectal evacuation. Clinically the internal anal sphincter was thickened and of decreased compliance. The maximum anal canal pressure was usually increased with marked ultraslow wave activity. Anal endosonography confirmed a grossly thickened internal anal sphincter. Two patients were treated by internal anal sphincter strip myectomy; one showed marked improvement and one was relieved of the constipation but had only slight improvement of the pain. The hypertrophied muscle in two of the patients showed unique myopathic changes, consisting of vacuolar changes with periodic acid-Schiff-positive polyglycosan bodies in the smooth muscle fibers and increased endomysial fibrosis. In vitro organ-bath studies showed insensitivity of the muscle to noradrenaline, isoprenaline, carbachol, dimethylpiperazinium, and electrical-field stimulation. Immunohistochemical studies for substance P, calcitonin gene-related peptide, galanin, neuropeptide Y, and vasoactive intestinal peptide showed staining in a similar distribution to that in control tissue. A specific autosomal-dominant inherited myopathy of the internal anal sphincter that causes anal pain and constipation has been identified and characterized.

An analysis of collegiate band directors' exposure to sound pressure levels

NASA Astrophysics Data System (ADS)

Roebuck, Nikole Moore

Noise-induced hearing loss (NIHL) is a significant but unfortunate common occupational hazard. The purpose of the current study was to measure the magnitude of sound pressure levels generated within a collegiate band room and determine if those sound pressure levels are of a magnitude that exceeds the policy standards and recommendations of the Occupational Safety and Health Administration (OSHA), and the National Institute of Occupational Safety and Health (NIOSH). In addition, reverberation times were measured and analyzed in order to determine the appropriateness of acoustical conditions for the band rehearsal environment. Sound pressure measurements were taken from the rehearsal of seven collegiate marching bands. Single sample t test were conducted to compare the sound pressure levels of all bands to the noise exposure standards of OSHA and NIOSH. Multiple regression analysis were conducted and analyzed in order to determine the effect of the band room's conditions on the sound pressure levels and reverberation times. Time weighted averages (TWA), noise percentage doses, and peak levels were also collected. The mean Leq for all band directors was 90.5 dBA. The total accumulated noise percentage dose for all band directors was 77.6% of the maximum allowable daily noise dose under the OSHA standard. The total calculated TWA for all band directors was 88.2% of the maximum allowable daily noise dose under the OSHA standard. The total accumulated noise percentage dose for all band directors was 152.1% of the maximum allowable daily noise dose under the NIOSH standards, and the total calculated TWA for all band directors was 93dBA of the maximum allowable daily noise dose under the NIOSH standard. Multiple regression analysis revealed that the room volume, the level of acoustical treatment and the mean room reverberation time predicted 80% of the variance in sound pressure levels in this study.

Lower Thoracic Spinal Cord Stimulation to Restore Cough in Patients with Spinal Cord Injury: Results of a National Institutes of Health-Sponsored Clinical Trial Part I: Methodology and Effectiveness of Expiratory Muscle Activation

PubMed Central

DiMarco, Anthony F.; Kowalski, Krzysztof E.; Geertman, Robert T.; Hromyak, Dana R.

2009-01-01

Objective Evaluation of the capacity of lower thoracic spinal cord stimulation (SCS) to activate the expiratory muscles and generate large airway pressures and high peak airflows characteristic of cough, in subjects with tetraplegia. Design Clinical trial. Setting In-patient hospital setting for electrode insertion; out-patient setting for measurement of respiratory pressures; home setting for application of SCS. Participants Subjects (N = 9; 8 men, 1 woman) with cervical spinal cord injury and weak cough. Intervention(s) A fully implantable electrical stimulation system was surgically placed in each subject. Partial hemilaminectomies were made to place single-disc electrodes in the epidural space at the T9, T11 and L1 spinal levels. A radiofrequency receiver was placed in the subcutaneous pocket over the anterior portion of the chest wall. Electrode wires were tunneled subcutaneously and connected to the receiver. Stimulation was applied by activating a small portable external stimulus controller box powered by a rechargeable battery to each electrode lead alone and in combination. Main Outcome Measure(s) Airway pressure and peak airflow generation achieved with SCS. Results Supramaximal SCS resulted in large airway pressures and high peak airflow rates during stimulation at each electrode lead. Maximum airway pressures and peak airflow rates were achieved with combined stimulation of any 2 leads. At total lung capacity, mean maximum airway pressure generation and peak airflow rates were 137 ± 30 cmH2O (mean ± SE) and 8.6 ± 1.8 (mean ± SE) L/s, respectively. Conclusions Lower thoracic SCS results in near maximum activation of the expiratory muscles and the generation of high positive airway pressures and peak airflow rates in the range of those observed with maximum cough efforts in normal individuals. PMID:19406289

Blood pressure normalization post-jugular venous balloon angioplasty.

PubMed

Sternberg, Zohara; Grewal, Prabhjot; Cen, Steven; DeBarge-Igoe, Frances; Yu, Jinhee; Arata, Michael

2015-05-01

This study is the first in a series investigating the relationship between autonomic nervous system dysfunction and chronic cerebrospinal venous insufficiency in multiple sclerosis patients. We screened patients for the combined presence of the narrowing of the internal jugular veins and symptoms of autonomic nervous system dysfunction (fatigue, cognitive dysfunction, sleeping disorders, headache, thermal intolerance, bowel/bladder dysfunction) and determined systolic and diastolic blood pressure responses to balloon angioplasty. The criteria for eligibility for balloon angioplasty intervention included ≥ 50% narrowing in one or both internal jugular veins, as determined by the magnetic resonance venography, and ≥ 3 clinical symptoms of autonomic nervous system dysfunction. Blood pressure was measured at baseline and post-balloon angioplasty. Among patients who were screened, 91% were identified as having internal jugular veins narrowing (with obstructing lesions) combined with the presence of three or more symptoms of autonomic nervous system dysfunction. Balloon angioplasty reduced the average systolic and diastolic blood pressure. However, blood pressure categorization showed a biphasic response to balloon angioplasty. The procedure increased blood pressure in multiple sclerosis patients who presented with baseline blood pressure within lower limits of normal ranges (systolic ≤ 105 mmHg, diastolic ≤ 70 mmHg) but decreased blood pressure in patients with baseline blood pressure above normal ranges (systolic ≥ 130 mmHg, diastolic ≥ 80 mmHg). In addition, gender differences in baseline blood pressure subcategories were observed. The coexistence of internal jugular veins narrowing and symptoms of autonomic nervous system dysfunction suggests that the two phenomena may be related. Balloon angioplasty corrects blood pressure deviation in multiple sclerosis patients undergoing internal jugular vein dilation. Further studies should investigate the association between blood pressure deviation and internal jugular veins narrowing, and whether blood pressure normalization affects Patient's clinical outcomes. © The Author(s) 2013 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.

Sonic boom prediction for the Langley Mach 2 low-boom configuration

NASA Technical Reports Server (NTRS)

Madson, Michael D.

1992-01-01

Sonic boom pressure signatures and aerodynamic force data for the Langley Mach 2 low sonic boom configuration were computed using the TranAir full-potential code. A solution-adaptive Cartesian grid scheme is utilized to compute off-body flow field data. Computations were performed with and without nacelles at several angles of attack. Force and moment data were computed to measure nacelle effects on the aerodynamic characteristics and sonic boom footprints of the model. Pressure signatures were computed both on and off ground-track. Near-field pressure signature computations on ground-track were in good agreement with experimental data. Computed off ground-track signatures showed that maximum pressure peaks were located off ground-track and were significantly higher than the signatures on ground-track. Bow shocks from the nacelle inlets increased lift and drag, and also increased the magnitude of the maximum pressure both on and off ground-track.

Optimizing working space in porcine laparoscopy: CT measurement of the effects of intra-abdominal pressure.

PubMed

Vlot, John; Wijnen, Rene; Stolker, Robert Jan; Bax, Klaas

2013-05-01

Several factors may affect volume and dimensions of the working space in laparoscopic surgery. The precise impact of these factors has not been well studied. In a porcine model, we used computed tomographic (CT) scanning for measuring working space volume and distances. In a first series of experiments, we studied the relationship between intra-abdominal pressure (IAP) and working space. Eleven 20 kg pigs were studied under standardized anesthesia and volume-controlled ventilation. Cardiorespiratory parameters were monitored continuously, and blood gas samples were taken at different IAP levels. Respiratory rate was increased when ETCO₂ exceeded 7 kPa. Breath-hold CT scans were made at IAP levels of 0, 5, 10, and 15 mmHg. Insufflator volumes were compared to CT-measured volumes. Maximum dimensions of pneumoperitoneum were measured on reconstructed CT images. Respiratory rate had to be increased in three animals. Mild hypercapnia and acidosis occurred at 15 mmHg IAP. Peak inspiratory pressure rose significantly at 10 and 15 mmHg. CT-measured volume increased relatively by 93 % from 5 to 10 mmHg IAP and by 19 % from 10 to 15 mmHg IAP. Comparing CT volumes to insufflator volumes gave a bias of 76 mL. The limits of agreement were -0.31 to +0.47, a range of 790 mL. The internal anteroposterior diameter increased by 18 % by increasing IAP from 5 to 10 mmHg and by 5 % by increasing IAP from 10 to 15 mmHg. At 15 mmHg, the total relative increase of the pubis-diaphragm distance was only 6 %. Abdominal width did not increase. CT allows for precise calculation of the actual CO₂ pneumoperitoneum volume, whereas the volume of CO₂ released by the insufflator does not. Increasing IAP up to 10 mmHg achieved most gain in volume and in internal anteroposterior diameter. At an IAP of 10 mmHg, higher peak inspiratory pressure was significantly elevated.

The Effect of Internal Pressure on the Buckling Stress of Thin-Walled Circular Cylinders Under Torsion

NASA Technical Reports Server (NTRS)

Crate, Harold; Batdorf, S B; Baab, George W

1944-01-01

The results of a series of tests to determine the effect of internal pressure on the buckling load of a thin cylinder under an applied torque indicated that internal pressure raises the shear buckling stress. The experimental results were analyzed with the aid of previously developed theory and a simple interaction formula was derived. (author)

Distribution of internal pressure around bony prominences: implications to deep tissue injury and effectiveness of intermittent electrical stimulation.

PubMed

Solis, Leandro R; Liggins, Adrian; Uwiera, Richard R E; Poppe, Niek; Pehowich, Enid; Seres, Peter; Thompson, Richard B; Mushahwar, Vivian K

2012-08-01

The overall goal of this project is to develop interventions for the prevention of deep tissue injury (DTI), a form of pressure ulcers that originates in deep tissue around bony prominences. The present study focused on: (1) obtaining detailed measures of the distribution of pressure experienced by tissue around the ischial tuberosities, and (2) investigating the effectiveness of intermittent electrical stimulation (IES), a novel strategy for the prevention of DTI, in alleviating pressure in regions at risk of breakdown due to sustained loading. The experiments were conducted in adult pigs. Five animals had intact spinal cords and healthy muscles and one had a spinal cord injury that led to substantial muscle atrophy at the time of the experiment. A force-controlled servomotor was used to load the region of the buttocks to levels corresponding to 25%, 50% or 75% of each animal's body weight. A pressure transducer embedded in a catheter was advanced into the tissue to measure pressure along a three dimensional grid around the ischial tuberosity of one hind leg. For all levels of external loading in intact animals, average peak internal pressure was 2.01 ± 0.08 times larger than the maximal interfacial pressure measured at the level of the skin. In the animal with spinal cord injury, similar absolute values of internal pressure as that in intact animals were recorded, but the substantial muscle atrophy produced larger maximal interfacial pressures. Average peak internal pressure in this animal was 1.43 ± 0.055 times larger than the maximal interfacial pressure. Peak internal pressure was localized within a ±2 cm region medio-laterally and dorso-ventrally from the bone in intact animals and ±1 cm in the animal with spinal cord injury. IES significantly redistributed internal pressure, shifting the peak values away from the bone in spinally intact and injured animals. These findings provide critical information regarding the relationship between internal and interfacial pressure around the ischial tuberosities during loading levels equivalent to those experienced while sitting. The information could guide future computer models investigating the etiology of DTI, as well as inform the design and prescription of seating cushions for people with reduced mobility. The findings also suggest that IES may be an effective strategy for the prevention of DTI.

Clostridium beijerinckii mutant obtained atmospheric pressure glow discharge generates enhanced electricity in a microbial fuel cell.

PubMed

Liu, Jun; Guo, Ting; Wang, Dong; Ying, Hanjie

2015-01-01

A Clostridium beijerinckii mutant M13 was derived from C. beijerinckii NCIMB 8052 by atmospheric pressure glow discharge. C. beijerinckii M13 generated a maximum output power density of 79.2 mW m(-2) and a maximum output voltage of 230 mV in a microbial fuel cell containing 1 g glucose l(-1) as carbon source and 0.15 g methyl viologen l(-1) as an electron carrier.

Gait analysis in hallux valgus.

PubMed

Blomgren, M; Turan, I; Agadir, M

1991-01-01

The solar pressure zones were analyzed in the feet of 66 patients suffering from hallux valgus, together with 60 normal subjects. The EMED Gait Analysis System was used. In the hallux valgus group, the maximum pressure was found to be increased significantly in the small toe region and more proximally situated, close to the metatarsophalangeal joint. In the normal subjects, the maximum pressure was increased significantly in the first, second, third, and fourth metatarsal and heel regions. In general, the hallux valgus group had smaller contact areas compared to the control group. The increased pressure in the small toe region, together with the smaller contact areas manifested by the hallux valgus group, were interpreted in this work as being the possible causes of the metatarsalgia seen in patients with the deformity.

Experimental investigation of inlet-combustor isolators for a dual-mode scramjet at a Mach number of 4

NASA Technical Reports Server (NTRS)

Emami, Saied; Trexler, Carl A.; Auslender, Aaron H.; Weidner, John P.

1995-01-01

This report details experimentally derived operational characteristics of numerous two-dimensional planar inlet-combustor isolator configurations at a Mach number of 4. Variations in geometry included (1) inlet cowl length; (2) inlet cowl rotation angle; (3) isolator length; and (4) utilization of a rearward-facing isolator step. To obtain inlet-isolator maximum pressure-rise data relevant to ramjet-engine combustion operation, configurations were mechanically back pressured. Results demonstrated that the combined inlet-isolator maximum back-pressure capability increases as a function of isolator length and contraction ratio, and that the initiation of unstart is nearly independent of inlet cowl length, inlet cowl contraction ratio, and mass capture. Additionally, data are presented quantifying the initiation of inlet unstarts and the corresponding unstart pressure levels.

The behavior of nanothermite reaction based on Bi2O3/Al

NASA Astrophysics Data System (ADS)

Wang, L.; Luss, D.; Martirosyan, K. S.

2011-10-01

We studied the impact of aluminum particle size and the thickness of surrounding alumina layer on the dynamic pressure discharge of nanothermite reactions in the Bi2O3/Al system. A pressure discharge from 9 to 13 MPa was generated using as-synthesized Bi2O3 nano-particles produced by combustion synthesis and Al nanoparticles with size from 3 μm to 100 nm. The maximum reaction temperature was measured to be ˜2700 °C. The estimated activation energy of the reaction was 45 kJ/mol. A very large (several orders of magnitude) difference existed between the rate of the pressure pulse release by nanothermite reactions and by thermite reactions with large aluminum particles. The maximum observed pressurization rate was 3200 GPa/s. The time needed to reach the peak pressure was 0.01 ms and 100 ms for aluminum particles with diameter of 100 nm and 70 microns, respectively. The discharge pressure was a monotonic decreasing function of the thickness of the surrounding alumina layer.

Simultaneous measurement of pressure evolution of crystal structure and superconductivity in FeSe[subscript 0.92] using designer diamonds

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

Uhoya, Walter; Tsoi, Georgiy; Vohra, Yogesh

Simultaneous high-pressure X-ray diffraction and electrical resistance measurements have been carried out on a PbO-type {alpha}-FeSe{sub 0.92} compound to a pressure of 44 GPa and temperatures down to 4 K using designer diamond anvils at synchrotron source. A ambient temperature, a structural phase transition from a tetragonal (P4/nmm) phase to an orthorhombic (Pbnm) phase is observed at 11 GPa and the Pbnm phase persists up to 74 GPa. The superconducting transition temperature (T{sub c}) increases rapidly with pressure reaching a maximum of {approx}28 K at {approx}6 GPa and decreases at higher pressures, disappearing completely at 14.6 GPa. Simultaneous pressure-dependent X-raymore » diffraction and resistance measurements at low temperatures show superconductivity only in a low-pressure orthorhombic (Cmma) phase of the {alpha}-FeSe{sub 0.92}. Upon increasing pressure at 10 K near T{sub c}, crystalline phases change from a mixture of orthorhombic (Cmma) and hexagonal (P63/mmc) phases to a high-pressure orthorhombic (Pbnm) phase near 6.4 GPa where T{sub c} is maximum.« less

Numerical Investigation of the Influence of the Input Air Irregularity on the Performance of Turbofan Jet Engine

NASA Astrophysics Data System (ADS)

Novikova, Y.; Zubanov, V.

2018-01-01

The article describes the numerical investigation of the input air irregularity influence of turbofan engine on its characteristics. The investigated fan has a wide-blade, an inlet diameter about 2 meters, a pressure ratio about 1.6 and the bypass ratio about 4.8. The flow irregularity was simulated by the flap input in the fan inlet channel. Input of flap was carried out by an amount of 10 to 22,5% of the input channel diameter with increments of 2,5%. A nonlinear harmonic analysis (NLH-analysis) of NUMECA Fine/Turbo software was used to study the flow irregularity. The behavior of the calculated LPC characteristics repeats the experiment behavior, but there is a quantitative difference: the calculated efficiency and pressure ratio of booster consistent with the experimental data within 3% and 2% respectively, the calculated efficiency and pressure ratio of fan duct - within 4% and 2.5% respectively. An increasing the level of air irregularity in the input stage of the fan reduces the calculated mass flow, maximum pressure ratio and efficiency. With the value of flap input 12.5%, reducing the maximum air flow is 1.44%, lowering the maximum pressure ratio is 2.6%, efficiency decreasing is 3.1%.

40 CFR 1065.720 - Liquefied petroleum gas.

Code of Federal Regulations, 2010 CFR

2010-07-01

..., C3H8 Minimum, 0.85 m3/m3 ASTM D2163-05. Vapor pressure at 38 °C Maximum, 1400 kPa ASTM D1267-02 or 2598-022. Volatility residue (evaporated temperature, 35 °C) Maximum, −38 °C ASTM D1837-02a. Butanes Maximum, 0.05 m3/m3 ASTM D2163-05. Butenes Maximum, 0.02 m3/m3 ASTM D2163-05. Pentenes and heavier Maximum...

46 CFR 151.50-42 - Ethyl ether.

Code of Federal Regulations, 2011 CFR

2011-10-01

... openings shall be in the top of the tank. (2) Pressure vessel type tanks shall be designed for the maximum pressure to which they may be subjected when pressure is used to discharge the cargo, but in no case shall the design pressure be less than 50 pounds per square inch gauge. All openings shall be in the top of...

46 CFR 151.50-42 - Ethyl ether.

Code of Federal Regulations, 2014 CFR

2014-10-01

... openings shall be in the top of the tank. (2) Pressure vessel type tanks shall be designed for the maximum pressure to which they may be subjected when pressure is used to discharge the cargo, but in no case shall the design pressure be less than 50 pounds per square inch gauge. All openings shall be in the top of...

46 CFR 151.50-42 - Ethyl ether.

Code of Federal Regulations, 2013 CFR

2013-10-01

... openings shall be in the top of the tank. (2) Pressure vessel type tanks shall be designed for the maximum pressure to which they may be subjected when pressure is used to discharge the cargo, but in no case shall the design pressure be less than 50 pounds per square inch gauge. All openings shall be in the top of...

Evaluation of Ultra High Pressure (UHP) Firefighting in a Room-and-Contents Fire

DTIC Science & Technology

2017-03-15

Burn Room and Hangar Temperature Prior to Ignition ............................................... 18 Figure 12. Effect of Temperature on Normalized...Figure 20. Maximum Average Temperature and Heat Flux ......................................................... 22 Figure 21. Effect of Maximum Average...Aspirated Ceiling Temperature .................................... 23 Figure 22. Effect of Maximum Average Floor Heat Flux on Extinguishment Quantity

The Relationship Between Maximum Isometric Strength and Ball Velocity in the Tennis Serve.

PubMed

Baiget, Ernest; Corbi, Francisco; Fuentes, Juan Pedro; Fernández-Fernández, Jaime

2016-12-01

The aims of this study were to analyze the relationship between maximum isometric strength levels in different upper and lower limb joints and serve velocity in competitive tennis players as well as to develop a prediction model based on this information. Twelve male competitive tennis players (mean ± SD; age: 17.2 ± 1.0 years; body height: 180.1 ± 6.2 cm; body mass: 71.9 ± 5.6 kg) were tested using maximum isometric strength levels (i.e., wrist, elbow and shoulder flexion and extension; leg and back extension; shoulder external and internal rotation). Serve velocity was measured using a radar gun. Results showed a strong positive relationship between serve velocity and shoulder internal rotation (r = 0.67; p < 0.05). Low to moderate correlations were also found between serve velocity and wrist, elbow and shoulder flexion - extension, leg and back extension and shoulder external rotation (r = 0.36 - 0.53; p = 0.377 - 0.054). Bivariate and multivariate models for predicting serve velocity were developed, with shoulder flexion and internal rotation explaining 55% of the variance in serve velocity (r = 0.74; p < 0.001). The maximum isometric strength level in shoulder internal rotation was strongly related to serve velocity, and a large part of the variability in serve velocity was explained by the maximum isometric strength levels in shoulder internal rotation and shoulder flexion.

Internal combustion engine for natural gas compressor operation

DOEpatents

Hagen, Christopher L.; Babbitt, Guy; Turner, Christopher; Echter, Nick; Weyer-Geigel, Kristina

2016-04-19

This application concerns systems and methods for compressing natural gas with an internal combustion engine. In a representative embodiment, a system for compressing a gas comprises a reciprocating internal combustion engine including at least one piston-cylinder assembly comprising a piston configured to travel in a cylinder and to compress gas in the cylinder in multiple compression stages. The system can further comprise a first pressure tank in fluid communication with the piston-cylinder assembly to receive compressed gas from the piston-cylinder assembly until the first pressure tank reaches a predetermined pressure, and a second pressure tank in fluid communication with the piston-cylinder assembly and the first pressure tank. The second pressure tank can be configured to receive compressed gas from the piston-cylinder assembly until the second pressure tank reaches a predetermined pressure. When the first and second pressure tanks have reached the predetermined pressures, the first pressure tank can be configured to supply gas to the piston-cylinder assembly, and the piston can be configured to compress the gas supplied by the first pressure tank such that the compressed gas flows into the second pressure tank.

Design and performance of tapered cubic anvil used for achieving higher pressure and larger sample cell

NASA Astrophysics Data System (ADS)

Han, Qi-Gang; Yang, Wen-Ke; Zhu, Pin-Wen; Ban, Qing-Chu; Yan, Ni; Zhang, Qiang

2013-07-01

In order to increase the maximum cell pressure of the cubic high pressure apparatus, we have developed a new structure of tungsten carbide cubic anvil (tapered cubic anvil), based on the principle of massive support and lateral support. Our results indicated that the tapered cubic anvil has some advantages. First, tapered cubic anvil can push the transfer rate of pressure well into the range above 36.37% compare to the conventional anvil. Second, the rate of failure crack decreases about 11.20% after the modification of the conventional anvil. Third, the limit of static high-pressure in the sample cell can be extended to 13 GPa, which can increase the maximum cell pressure about 73.3% than that of the conventional anvil. Fourth, the volume of sample cell compressed by tapered cubic anvils can be achieved to 14.13 mm3 (3 mm diameter × 2 mm long), which is three and six orders of magnitude larger than that of double-stage apparatus and diamond anvil cell, respectively. This work represents a relatively simple method for achieving higher pressures and larger sample cell.

Liquid Nitrogen Subcooler Pressure Vessel Engineering Note

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

Rucinski, R.; /Fermilab

1997-04-24

The normal operating pressure of this dewar is expected to be less than 15 psig. This vessel is open to atmospheric pressure thru a non-isolatable vent line. The backpressure in the vent line was calculated to be less than 1.5 psig at maximum anticipated flow rates.

Miniaturised electrically actuated high pressure injection valve for portable capillary liquid chromatography.

PubMed

Li, Yan; Pace, Kirsten; Nesterenko, Pavel N; Paull, Brett; Stanley, Roger; Macka, Mirek

2018-04-01

A miniaturised high pressure 6-port injection valve has been designed and evaluated for its performance in order to facilitate the development of portable capillary high performance liquid chromatography (HPLC). The electrically actuated valve features a very small size (65 × 19 × 19mm) and light weight (33g), and therefore can be easily integrated in a miniaturised modular capillary LC system suited for portable field analysis. The internal volume of the injection valve was determined as 98 nL. The novel conical shape of the stator and rotor and the spring-loaded rotor performed well up to 32MPa (4641psi), the maximum operating pressure investigated. Suitability for application was demonstrated using a miniaturised capillary LC system applied to the chromatographic separation of a mixture of biogenic amines and common cations. The RSD (relative standard deviation) values of retention times and peak areas of 6 successive runs were 0.5-0.7% and 1.8-2.8% for the separation of biogenic amines, respectively, and 0.1-0.2% and 2.1-3.0% for the separation of cations, respectively. This performance was comparable with bench-top HPLC systems thus demonstrating the applicability of the valve for use in portable and miniaturised capillary HPLC systems. Copyright © 2017 Elsevier B.V. All rights reserved.

Blended-Wing-Body (BWB) Fuselage Structural Design for Weight Reduction

NASA Technical Reports Server (NTRS)

Mukhopadhyay, V.

2005-01-01

Structural analysis and design of efficient pressurized fuselage configurations for the advanced Blended-Wing-Body (BWB) flight vehicle is a challenging problem. Unlike a conventional cylindrical pressurized fuselage, stress level in a box type BWB fuselage is an order of magnitude higher, because internal pressure primarily results in bending stress instead of skin-membrane stress. In addition, resulting deformation of aerodynamic surface could significantly affect performance advantages provided by lifting body. The pressurized composite conformal multi-lobe tanks of X-33 type space vehicle also suffered from similar problem. In the earlier BWB design studies, Vaulted Ribbed Shell (VLRS), Flat Ribbed Shell (FRS); Vaulted shell Honeycomb Core (VLHC) and Flat sandwich shell Honeycomb Core (FLHC) concepts were studied. The flat and vaulted ribbed shell concepts were found most efficient. In a recent study, a set of composite sandwich panel and cross-ribbed panel were analyzed. Optimal values of rib and skin thickness, rib spacing, and panel depth were obtained for minimal weight under stress and buckling constraints. In addition, a set of efficient multi-bubble fuselage (MBF) configuration concept was developed. The special geometric configuration of this concept allows for balancing internal cabin pressure load efficiently, through membrane stress in inner-stiffened shell and inter-cabin walls, while the outer-ribbed shell prevents buckling due to external resultant compressive loads. The initial results from these approximate finite element analyses indicate progressively lower maximum stresses and deflections compared to the earlier study. However, a relative comparison of the FEM weight per unit floor area of the segment unit indicates that the unit weights are still relatively higher that the conventional B777 type cylindrical or A380 type elliptic fuselage design. Due to the manufacturing concern associated with multi-bubble fuselage, a Y braced box-type fuselage alternative with special resin-film injected (RFI) stitched carbon composite with foam-core was designed by Boeing under a NASA research contract for the 480 passenger version. It is shown that this configuration can be improved to a modified multi-bubble fuselage which has better stress distribution, for same material and dimension.

Fluid relief and check valve

DOEpatents

Blaedel, K.L.; Lord, S.C.; Murray, I.

1986-07-17

A passive fluid pressure relief and check valve allows the relief pressure to be slaved to a reference pressure independently of the exhaust pressure. The pressure relief valve is embodied by a submerged vent line in a sealing fluid, the relief pressure being a function of the submerged depth. A check valve is embodied by a vertical column of fluid (the maximum back pressure being a function of the height of the column of fluid). The pressure is vented into an exhaust system which keeps the exhaust out of the area providing the reference pressure.

Internal combustion engine cylinder-to-cylinder balancing with balanced air-fuel ratios

DOEpatents

Harris, Ralph E.; Bourn, Gary D.; Smalley, Anthony J.

2006-01-03

A method of balancing combustion among cylinders of an internal combustion engine. For each cylinder, a normalized peak firing pressure is calculated as the ratio of its peak firing pressure to its combustion pressure. Each cylinder's normalized peak firing pressure is compared to a target value for normalized peak firing pressure. The fuel flow is adjusted to any cylinder whose normalized peak firing pressure is not substantially equal to the target value.

International certification in developing countries: the role of internal and external institutional pressure.

PubMed

Fikru, Mahelet G

2014-11-01

This paper examines the different internal and external institutional factors that affect the decision of businesses in developing countries to adopt international certification (IC). Past studies focus on pressure from international laws, the role of multinationals, and businesses mimicking practices of their counterparts in developed countries. This paper finds that, in addition to these external factors, internal factors may have a significant role. Even though environmental regulation is weak in developing countries, governments do not ignore industrial pollution and casualties. They respond by increasing bureaucratic regulations for businesses and this can affect the decision to adopt IC. Furthermore, internal pressure may come from workers' unions that push for a safe and healthy working environment. Published by Elsevier Ltd.

Controllable load sharing for soft adhesive interfaces on three-dimensional surfaces.

PubMed

Song, Sukho; Drotlef, Dirk-Michael; Majidi, Carmel; Sitti, Metin

2017-05-30

For adhering to three-dimensional (3D) surfaces or objects, current adhesion systems are limited by a fundamental trade-off between 3D surface conformability and high adhesion strength. This limitation arises from the need for a soft, mechanically compliant interface, which enables conformability to nonflat and irregularly shaped surfaces but significantly reduces the interfacial fracture strength. In this work, we overcome this trade-off with an adhesion-based soft-gripping system that exhibits enhanced fracture strength without sacrificing conformability to nonplanar 3D surfaces. Composed of a gecko-inspired elastomeric microfibrillar adhesive membrane supported by a pressure-controlled deformable gripper body, the proposed soft-gripping system controls the bonding strength by changing its internal pressure and exploiting the mechanics of interfacial equal load sharing. The soft adhesion system can use up to ∼26% of the maximum adhesion of the fibrillar membrane, which is 14× higher than the adhering membrane without load sharing. Our proposed load-sharing method suggests a paradigm for soft adhesion-based gripping and transfer-printing systems that achieves area scaling similar to that of a natural gecko footpad.

Controllable load sharing for soft adhesive interfaces on three-dimensional surfaces

NASA Astrophysics Data System (ADS)

Song, Sukho; Drotlef, Dirk-Michael; Majidi, Carmel; Sitti, Metin

2017-05-01

For adhering to three-dimensional (3D) surfaces or objects, current adhesion systems are limited by a fundamental trade-off between 3D surface conformability and high adhesion strength. This limitation arises from the need for a soft, mechanically compliant interface, which enables conformability to nonflat and irregularly shaped surfaces but significantly reduces the interfacial fracture strength. In this work, we overcome this trade-off with an adhesion-based soft-gripping system that exhibits enhanced fracture strength without sacrificing conformability to nonplanar 3D surfaces. Composed of a gecko-inspired elastomeric microfibrillar adhesive membrane supported by a pressure-controlled deformable gripper body, the proposed soft-gripping system controls the bonding strength by changing its internal pressure and exploiting the mechanics of interfacial equal load sharing. The soft adhesion system can use up to ˜26% of the maximum adhesion of the fibrillar membrane, which is 14× higher than the adhering membrane without load sharing. Our proposed load-sharing method suggests a paradigm for soft adhesion-based gripping and transfer-printing systems that achieves area scaling similar to that of a natural gecko footpad.

Charging conditions research to increase the initial projected velocity at different initial charge temperatures

NASA Astrophysics Data System (ADS)

Ishchenko, Aleksandr; Burkin, Viktor; Kasimov, Vladimir; Samorokova, Nina; Zykova, Angelica; Diachkovskii, Alexei

2017-11-01

The problems of the defense industry occupy the most important place in the constantly developing modern world. The daily development of defense technology does not stop, nor do studies on internal ballistics. The scientists of the whole world are faced with the task of managing the main characteristics of a ballistic experiment. The main characteristics of the ballistic experiment are the maximum pressure in the combustion chamber Pmax and the projected velocity at the time of barrel leaving UM. During the work the combustion law of the new high-energy fuel was determined in a ballistic experiment for different initial temperatures. This combustion law was used for a parametric study of depending Pmax and UM from a powder charge mass and a traveling charge was carried out. The optimal conditions for loading were obtained for improving the initial velocity at pressures up to 600 MPa for different initial temperatures. In this paper, one of the most promising schemes of throwing is considered, as well as a method for increasing the muzzle velocity of a projected element to 3317 m/s.

Positively charged microporous ceramic membrane for the removal of Titan Yellow through electrostatic adsorption.

PubMed

Cheng, Xiuting; Li, Na; Zhu, Mengfu; Zhang, Lili; Deng, Yu; Deng, Cheng

2016-06-01

To develop a depth filter based on the electrostatic adsorption principle, positively charged microporous ceramic membrane was prepared from a diatomaceous earth ceramic membrane. The internal surface of the highly porous ceramic membrane was coated with uniformly distributed electropositive nano-Y2O3 coating. The dye removal performance was evaluated through pressurized filtration tests using Titan Yellow aqueous solution. It showed that positively charged microporous ceramic membrane exhibited a flow rate of 421L/(m(2)·hr) under the trans-membrane pressure of 0.03bar. Moreover it could effectively remove Titan Yellow with feed concentration of 10mg/L between pH3 to 8. The removal rate increased with the enhancement of the surface charge properties with a maximum rejection of 99.6%. This study provides a new and feasible method of removing organic dyes in wastewater. It is convinced that there will be a broad market for the application of charged ceramic membrane in the field of dye removal or recovery from industry wastewater. Copyright © 2016. Published by Elsevier B.V.

Controllable load sharing for soft adhesive interfaces on three-dimensional surfaces

PubMed Central

Song, Sukho; Drotlef, Dirk-Michael; Majidi, Carmel; Sitti, Metin

2017-01-01

For adhering to three-dimensional (3D) surfaces or objects, current adhesion systems are limited by a fundamental trade-off between 3D surface conformability and high adhesion strength. This limitation arises from the need for a soft, mechanically compliant interface, which enables conformability to nonflat and irregularly shaped surfaces but significantly reduces the interfacial fracture strength. In this work, we overcome this trade-off with an adhesion-based soft-gripping system that exhibits enhanced fracture strength without sacrificing conformability to nonplanar 3D surfaces. Composed of a gecko-inspired elastomeric microfibrillar adhesive membrane supported by a pressure-controlled deformable gripper body, the proposed soft-gripping system controls the bonding strength by changing its internal pressure and exploiting the mechanics of interfacial equal load sharing. The soft adhesion system can use up to ∼26% of the maximum adhesion of the fibrillar membrane, which is 14× higher than the adhering membrane without load sharing. Our proposed load-sharing method suggests a paradigm for soft adhesion-based gripping and transfer-printing systems that achieves area scaling similar to that of a natural gecko footpad. PMID:28507143

The shape of the Eiffel Tower

NASA Astrophysics Data System (ADS)

Gallant, Joseph

2002-02-01

The distinctive shape of the Eiffel Tower is based on simple physics and is designed so that the maximum torque created by the wind is balanced by the torque due to the Tower's weight. We use this idea to generate an equation for the shape of the Tower. The solution depends only on the width of the base and the maximum wind pressure. We parametrize the wind pressure and reproduce the shape of the Tower. We also discuss some of the Tower's interesting history and characteristics.

Investigation of Composite Structures

NASA Technical Reports Server (NTRS)

Hyer, Michael W.

2000-01-01

This final report consists of a compilation of four separate written documents, three dealing with the response and failure of elliptical composite cylinders to an internal pressure load, and the fourth dealing with the influence of manufacturing imperfections in curved composite panels. The three focused on elliptical cylinders consist of the following: 1 - A paper entitled "Progressive Failure Analysis of Internally Pressurized Elliptical Composite Cylinders," 2 - A paper entitled "Influence of Geometric Nonlinearities on the Response and Failure of Internally Pressurized Elliptical Composite Cylinders," and 3 - A report entitled "Response and Failure of Internally Pressurized Elliptical Composite Cyclinders." The document which deals with the influence of manufacturing imperfections is a paper entitled "Manufacturing Distortions of Curved Composite Panels."

Variability of blood pressure in dialysis patients: a new marker of cardiovascular risk.

PubMed

Di Iorio, Biagio; Di Micco, Lucia; Torraca, Serena; Sirico, Maria Luisa; Guastaferro, Pasquale; Chiuchiolo, Luigi; Nigro, Filippo; De Blasio, Antonietta; Romano, Paolo; Pota, Andrea; Rubino, Roberto; Morrone, Luigi; Lopez, Teodoro; Casino, Francesco Gaetano

2013-01-01

Hemodialysis patients have a high cardiovascular mortality, and hypertension is the most prevalent treatable risk factor. We aimed to assess the predictive significance of dialysis-to-dialysis variability in blood pressure in hemodialysis patients. We performed a historical cohort study in 1,088 prevalent hemodialysis patients, followed up for 5 years. The risk of cardiovascular death was determined in relation to dialysis-to-dialysis variability in blood pressure, maximum blood pressure and pulse pressure. Variability in blood pressure was a predictor of cardiovascular death (hazard ratio [HR] = 1.242; 95% confidence interval [95% CI], 1.004-1.537; p=0.046). Also age (HR=1.021; 95% CI, 1.011-1.048; p=0.049), diabetes (HR=1.134; 95% CI, 1.128-1.451; p=0.035), creatinine (HR=0.837; 95% CI, 0.717-0.977; p=0.024) and albumin (HR=0.901; 95% CI, 0.821-0.924; p=0.022) influenced mortality. Maximum blood pressure and pulse pressure did not show any effect on cardiovascular death. Dialysis-to-dialysis variability in blood pressure is a predictor of cardiovascular mortality in hemodialysis patients, and blood pressure variability may be used in managing hypertension and predicting outcomes in dialysis patients.

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.

Wind Tunnel Model Design for the Study of Plume Effects on Sonic Boom for Isolated Exhaust Nozzles

NASA Technical Reports Server (NTRS)

Castner, Raynold S.

2010-01-01

A low cost test capability was developed at the NASA Glenn Research Center 1- by 1-Foot Supersonic Wind Tunnel (SWT), with a goal to reduce the disturbance caused by supersonic aircraft flight over populated areas. This work focused on the shock wave structure caused by the exhaust nozzle plume. Analysis and design was performed on a new rig to test exhaust nozzle plume effects on sonic boom signature. Test capability included a baseline nozzle test article and a wind tunnel model consisting of a strut, a nosecone and an upper plenum. Analysis was performed on the external and internal aerodynamic configuration, including the shock reflections from the wind tunnel walls caused by the presence of the model nosecone. This wind tunnel model was designed to operate from Mach 1.4 to Mach 3.0 with nozzle pressure ratios from 6 to 12 and altitudes from 30,000 ft (4.36 psia) to 50,000 ft (1.68 psia). The model design was based on a 1 in. outer diameter, was 9 in. in overall length, and was mounted in the wind tunnel on a 3/8 in. wide support strut. For test conditions at 50,000 ft the strut was built to supply 90 psia of pressure, and to achieve 20 psia at the nozzle inlet with a maximum nozzle pressure of 52 psia. Instrumentation was developed to measure nozzle pressure ratio, and an external static pressure probe was designed to survey near field static pressure profiles at one nozzle diameter above the rig centerline. Model layout placed test nozzles between two transparent sidewalls in the 1 1 SWT for Schlieren photography and comparison to CFD analysis.

Wind Tunnel Model Design for the Study of Plume Effects on Sonic Boom for Isolated Exhaust Nozzles

NASA Technical Reports Server (NTRS)

Castner, Raymond S.

2009-01-01

A low cost test capability was developed at the NASA Glenn Research Center 1- by 1-Foot Supersonic Wind Tunnel (SWT), with a goal to reduce the disturbance caused by supersonic aircraft flight over populated areas. This work focused on the shock wave structure caused by the exhaust nozzle plume. Analysis and design was performed on a new rig to test exhaust nozzle plume effects on sonic boom signature. Test capability included a baseline nozzle test article and a wind tunnel model consisting of a strut, a nose cone and an upper plenum. Analysis was performed on the external and internal aerodynamic configuration, including the shock reflections from the wind tunnel walls caused by the presence of the model nosecone. This wind tunnel model was designed to operate from Mach 1.4 to Mach 3.0 with nozzle pressure ratios from 6 to 12 and altitudes from 30,000 ft (4.36 psia) to 50,000 ft (1.68 psia). The model design was based on a 1 in. outer diameter, was 9 in. in overall length, and was mounted in the wind tunnel on a 3/8 in. wide support strut. For test conditions at 50,000 ft the strut was built to supply 90 psia of pressure, and to achieve 20 psia at the nozzle inlet with a maximum nozzle pressure of 52 psia. Instrumentation was developed to measure nozzle pressure ratio, and an external static pressure probe was designed to survey near field static pressure profiles at one nozzle diameter above the rig centerline. Model layout placed test nozzles between two transparent sidewalls in the 1x1 SWT for Schlieren photography and comparison to CFD analysis.

Localized bulging in an inflated cylindrical tube of arbitrary thickness - the effect of bending stiffness

NASA Astrophysics Data System (ADS)

Fu, Y. B.; Liu, J. L.; Francisco, G. S.

2016-05-01

We study localized bulging of a cylindrical hyperelastic tube of arbitrary thickness when it is subjected to the combined action of inflation and axial extension. It is shown that with the internal pressure P and resultant axial force F viewed as functions of the azimuthal stretch on the inner surface and the axial stretch, the bifurcation condition for the initiation of a localized bulge is that the Jacobian of the vector function (P , F) should vanish. This is established using the dynamical systems theory by first computing the eigenvalues of a certain eigenvalue problem governing incremental deformations, and then deriving the bifurcation condition explicitly. The bifurcation condition is valid for all loading conditions, and in the special case of fixed resultant axial force it gives the expected result that the initiation pressure for localized bulging is precisely the maximum pressure in uniform inflation. It is shown that even if localized bulging cannot take place when the axial force is fixed, it is still possible if the axial stretch is fixed instead. The explicit bifurcation condition also provides a means to quantify precisely the effect of bending stiffness on the initiation pressure. It is shown that the (approximate) membrane theory gives good predictions for the initiation pressure, with a relative error less than 5%, for thickness/radius ratios up to 0.67. A two-term asymptotic bifurcation condition for localized bulging that incorporates the effect of bending stiffness is proposed, and is shown to be capable of giving extremely accurate predictions for the initiation pressure for thickness/radius ratios up to as large as 1.2.

46 CFR 64.53 - Information plate for MPTs.

Code of Federal Regulations, 2010 CFR

2010-10-01

... name. (3) Date of manufacture. (4) Serial number of tank. (5) Maximum allowable working pressure in psig. (6) Test pressure in psig. (7) External-pressure rating in psig. (8) Total capacity in gallons... 122 °F. (12) Date of hydrostatic test. [CGD 84-043, 55 FR 37410, Sept. 11, 1990] ...

40 CFR 63.11583 - What are my monitoring requirements?

Code of Federal Regulations, 2012 CFR

2012-07-01

... applicable, and the following: (1) Locate the pressure sensor(s) in, or as close as possible to, a position... comparing the sensor output to redundant sensor output. (4) Conduct calibration checks any time the sensor exceeds the manufacturer's specified maximum operating pressure range or install a new pressure sensor. (5...

14 CFR 25.841 - Pressurized cabins.

Code of Federal Regulations, 2013 CFR

2013-01-01

... differentials up to the maximum relief valve setting in combination with landing loads. (8) The pressure sensors... located and the sensing system designed so that, in the event of loss of cabin pressure in any passenger... increase the hazards resulting from decompression. [Doc. No. 5066, 29 FR 18291, Dec. 24, 1964, as amended...

14 CFR 25.841 - Pressurized cabins.

Code of Federal Regulations, 2010 CFR

2010-01-01

... differentials up to the maximum relief valve setting in combination with landing loads. (8) The pressure sensors... located and the sensing system designed so that, in the event of loss of cabin pressure in any passenger... increase the hazards resulting from decompression. [Doc. No. 5066, 29 FR 18291, Dec. 24, 1964, as amended...

14 CFR 25.841 - Pressurized cabins.

Code of Federal Regulations, 2014 CFR

2014-01-01

... differentials up to the maximum relief valve setting in combination with landing loads. (8) The pressure sensors... located and the sensing system designed so that, in the event of loss of cabin pressure in any passenger... increase the hazards resulting from decompression. [Doc. No. 5066, 29 FR 18291, Dec. 24, 1964, as amended...

14 CFR 25.841 - Pressurized cabins.

Code of Federal Regulations, 2011 CFR

2011-01-01

... differentials up to the maximum relief valve setting in combination with landing loads. (8) The pressure sensors... located and the sensing system designed so that, in the event of loss of cabin pressure in any passenger... increase the hazards resulting from decompression. [Doc. No. 5066, 29 FR 18291, Dec. 24, 1964, as amended...

14 CFR 25.841 - Pressurized cabins.

Code of Federal Regulations, 2012 CFR

2012-01-01

... differentials up to the maximum relief valve setting in combination with landing loads. (8) The pressure sensors... located and the sensing system designed so that, in the event of loss of cabin pressure in any passenger... increase the hazards resulting from decompression. [Doc. No. 5066, 29 FR 18291, Dec. 24, 1964, as amended...

49 CFR 178.338-14 - Gauging devices.

Code of Federal Regulations, 2011 CFR

2011-10-01

... gauging devices, which accurately indicate the maximum permitted liquid level at the loading pressure, in... trycock line, or a differential pressure liquid level gauge must be used as the primary control for... filling. (2) The design pressure of each liquid level gauging device must be at least that of the tank. (3...

49 CFR 178.338-14 - Gauging devices.

Code of Federal Regulations, 2014 CFR

2014-10-01

... gauging devices, which accurately indicate the maximum permitted liquid level at the loading pressure, in... trycock line, or a differential pressure liquid level gauge must be used as the primary control for... filling. (2) The design pressure of each liquid level gauging device must be at least that of the tank. (3...

49 CFR 178.338-14 - Gauging devices.

Code of Federal Regulations, 2012 CFR

2012-10-01

... gauging devices, which accurately indicate the maximum permitted liquid level at the loading pressure, in... trycock line, or a differential pressure liquid level gauge must be used as the primary control for... filling. (2) The design pressure of each liquid level gauging device must be at least that of the tank. (3...

49 CFR 178.338-14 - Gauging devices.

Code of Federal Regulations, 2013 CFR

2013-10-01

... gauging devices, which accurately indicate the maximum permitted liquid level at the loading pressure, in... trycock line, or a differential pressure liquid level gauge must be used as the primary control for... filling. (2) The design pressure of each liquid level gauging device must be at least that of the tank. (3...

49 CFR 229.49 - Main reservoir system.

Code of Federal Regulations, 2012 CFR

2012-10-01

... inch above the maximum working air pressure fixed by the chief mechanical officer of the carrier... reservoir of air under pressure to be used for operating those power controls. The reservoir shall be provided with means to automatically prevent the loss of pressure in the event of a failure of main air...

49 CFR 229.49 - Main reservoir system.

Code of Federal Regulations, 2011 CFR

2011-10-01

... inch above the maximum working air pressure fixed by the chief mechanical officer of the carrier... reservoir of air under pressure to be used for operating those power controls. The reservoir shall be provided with means to automatically prevent the loss of pressure in the event of a failure of main air...