30 CFR 250.803 - Additional production system requirements.

Code of Federal Regulations, 2013 CFR

2013-07-01

... pressure vessels at any time when there is a change in operating pressures that requires new settings for... significant change in operating pressures. The most recent pressure-recorder charts used to determine... subfreezing climates, the lessee shall furnish evidence to the District Manager that the firefighting system...

30 CFR 250.803 - Additional production system requirements.

Code of Federal Regulations, 2010 CFR

2010-07-01

... ranges of pressure vessels at any time when there is a change in operating pressures that requires new... significant change in operating pressures. The most recent pressure-recorder charts used to determine... prominent place on the facility or structure. (v) For operations in subfreezing climates, the lessee shall...

Version pressure feedback mechanisms for speculative versioning caches

DOEpatents

Eichenberger, Alexandre E.; Gara, Alan; O& #x27; Brien, Kathryn M.; Ohmacht, Martin; Zhuang, Xiaotong

2013-03-12

Mechanisms are provided for controlling version pressure on a speculative versioning cache. Raw version pressure data is collected based on one or more threads accessing cache lines of the speculative versioning cache. One or more statistical measures of version pressure are generated based on the collected raw version pressure data. A determination is made as to whether one or more modifications to an operation of a data processing system are to be performed based on the one or more statistical measures of version pressure, the one or more modifications affecting version pressure exerted on the speculative versioning cache. An operation of the data processing system is modified based on the one or more determined modifications, in response to a determination that one or more modifications to the operation of the data processing system are to be performed, to affect the version pressure exerted on the speculative versioning cache.

Remotely operated high pressure valve protects test personnel

NASA Technical Reports Server (NTRS)

Howland, B. T.

1967-01-01

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

A Simplified Instrument for Recording and Indicating Frequency and Intensity of Icing Conditions Encountered in Flight

NASA Technical Reports Server (NTRS)

Perkins, Porter J; Mccullough, Stuart; Lewis, Ralph D

1951-01-01

An instrument for recording and indicating the frequency and intensity of aircraft icing conditions encountered in flight has been developed by the NACA Lewis Laboratory to obtain statistical icing data over world-wide air routes during routine airline operations. The operation of the instrument is based on the creation of a differential pressure between an ice-free total-pressure system and a total-pressure system in which small total-pressure holes vented to static pressure are allowed to plug with ice accretion. The simplicity of this operating principle permits automatic operation, and provides relative freedom from maintenance and operating problems. The complete unit weighing only 18 pounds records icing rate, airspeed, and altitude on photographic film and provides visual indications of icing intensity to the pilot.

Pneumatic load compensating or controlling system

NASA Technical Reports Server (NTRS)

Rogers, J. R. (Inventor)

1975-01-01

A pneumatic load compensating or controlling system for restraining a load with a predetermined force or applying a predetermined force to the load is described; it includes a source of pressurized air, a one-way pneumatic actuator operatively connected to a load, and a fluid conduit fluidically connecting the actuator with the source of pressurized air. The actuator is of the piston and cylinder type, and the end of the fluid conduit is connected to the upper or lower portion of the cylinder whereby the actuator alternatively and selectively restrains the load with a predetermined force or apply a predetermined force to the load. Pressure regulators are included within the system for variably selectively adjusting the pressurized fluid to predetermined values as desired or required; a pressure amplifier is included within the system for multiplying the pressurized values so as to achieve greater load forces. An accumulator is incorporated within the system as a failsafe operating mechanism, and visual and aural alarm devices, operatively associated with pressure detecting apparatus, readily indicate the proper or improper functioning of the system.

Control rod drive hydraulic system

DOEpatents

Ose, Richard A.

1992-01-01

A hydraulic system for a control rod drive (CRD) includes a variable output-pressure CR pump operable in a charging mode for providing pressurized fluid at a charging pressure, and in a normal mode for providing the pressurized fluid at a purge pressure, less than the charging pressure. Charging and purge lines are disposed in parallel flow between the CRD pump and the CRD. A hydraulic control unit is disposed in flow communication in the charging line and includes a scram accumulator. An isolation valve is provided in the charging line between the CRD pump and the scram accumulator. A controller is operatively connected to the CRD pump and the isolation valve and is effective for opening the isolation valve and operating the CRD pump in a charging mode for charging the scram accumulator, and closing the isolation valve and operating the CRD pump in a normal mode for providing to the CRD through the purge line the pressurized fluid at a purge pressure lower than the charging pressure.

Pressure-Letdown Machine for a Coal Reactor

NASA Technical Reports Server (NTRS)

Perkins, G. S.; Mabe, W. B.

1986-01-01

Pumps operating in reverse generate power. Conceptual pressure-letdown machine for coal-liquefaction system extracts energy from expansion of product fluid. Mud pumps, originally intended for use in oil drilling, operated in reverse so their motors act as generators. Several pumps operated in alternating phase to obtain multiple stages of letdown from inlet pressure to outlet pressure. About 75 percent of work generates inlet pressure recoverable as electrical energy.

46 CFR 151.40-10 - Operational requirements.

Code of Federal Regulations, 2011 CFR

2011-10-01

... CARRYING BULK LIQUID HAZARDOUS MATERIAL CARGOES Temperature or Pressure Control Installations § 151.40-10... visual high cargo temperature or high cargo pressure alarm which is discernible at the towboat. The alarm shall operate when either the pressure or the temperature exceeds the operating limits of the system...

46 CFR 151.40-10 - Operational requirements.

Code of Federal Regulations, 2014 CFR

2014-10-01

... CARRYING BULK LIQUID HAZARDOUS MATERIAL CARGOES Temperature or Pressure Control Installations § 151.40-10... visual high cargo temperature or high cargo pressure alarm which is discernible at the towboat. The alarm shall operate when either the pressure or the temperature exceeds the operating limits of the system...

46 CFR 151.40-10 - Operational requirements.

Code of Federal Regulations, 2013 CFR

2013-10-01

... CARRYING BULK LIQUID HAZARDOUS MATERIAL CARGOES Temperature or Pressure Control Installations § 151.40-10... visual high cargo temperature or high cargo pressure alarm which is discernible at the towboat. The alarm shall operate when either the pressure or the temperature exceeds the operating limits of the system...

46 CFR 151.40-10 - Operational requirements.

Code of Federal Regulations, 2012 CFR

2012-10-01

... CARRYING BULK LIQUID HAZARDOUS MATERIAL CARGOES Temperature or Pressure Control Installations § 151.40-10... visual high cargo temperature or high cargo pressure alarm which is discernible at the towboat. The alarm shall operate when either the pressure or the temperature exceeds the operating limits of the system...

Thermal stratification in LH2 tank of cryogenic propulsion stage tested in ISRO facility

NASA Astrophysics Data System (ADS)

Xavier, M.; Raj, R. Edwin; Narayanan, V.

2017-02-01

Liquid oxygen and hydrogen are used as oxidizer and fuel respectively in cryogenic propulsion system. These liquids are stored in foam insulated tanks of cryogenic propulsion system and are pressurized using warm pressurant gas supplied for tank pressure maintenance during cryogenic engine operation. Heat leak to cryogenic propellant tank causes buoyancy driven liquid stratification resulting in formation of warm liquid stratum at liquid free surface. This warm stratum is further heated by the admission of warm pressurant gas for tank pressurization during engine operation. Since stratified layer temperature has direct bearing on the cavitation free operation of turbo pumps integrated in cryogenic engine, it is necessary to model the thermal stratification for predicting stratified layer temperature and mass of stratified liquid in tank at the end of engine operation. These inputs are required for estimating the minimum pressure to be maintained by tank pressurization system. This paper describes configuration of cryogenic stage for ground qualification test, stage hot test sequence, a thermal model and its results for a foam insulated LH2 tank subjected to heat leak and pressurization with hydrogen gas at 200 K during liquid outflow at 38 lps for engine operation. The above model considers buoyancy flow in free convection boundary layer caused by heat flux from tank wall and energy transfer from warm pressurant gas etc. to predict temperature of liquid stratum and mass of stratified liquid in tank at the end of engine operation in stage qualification tests carried out in ISRO facility.

Computational analysis of aircraft pressure relief doors

NASA Astrophysics Data System (ADS)

Schott, Tyler

Modern trends in commercial aircraft design have sought to improve fuel efficiency while reducing emissions by operating at higher pressures and temperatures than ever before. Consequently, greater demands are placed on the auxiliary bleed air systems used for a multitude of aircraft operations. The increased role of bleed air systems poses significant challenges for the pressure relief system to ensure the safe and reliable operation of the aircraft. The core compartment pressure relief door (PRD) is an essential component of the pressure relief system which functions to relieve internal pressure in the core casing of a high-bypass turbofan engine during a burst duct over-pressurization event. The successful modeling and analysis of a burst duct event are imperative to the design and development of PRD's to ensure that they will meet the increased demands placed on the pressure relief system. Leveraging high-performance computing coupled with advances in computational analysis, this thesis focuses on a comprehensive computational fluid dynamics (CFD) study to characterize turbulent flow dynamics and quantify the performance of a core compartment PRD across a range of operating conditions and geometric configurations. The CFD analysis was based on a compressible, steady-state, three-dimensional, Reynolds-averaged Navier-Stokes approach. Simulations were analyzed, and results show that variations in freestream conditions, plenum environment, and geometric configurations have a non-linear impact on the discharge, moment, thrust, and surface temperature characteristics. The CFD study revealed that the underlying physics for this behavior is explained by the interaction of vortices, jets, and shockwaves. This thesis research is innovative and provides a comprehensive and detailed analysis of existing and novel PRD geometries over a range of realistic operating conditions representative of a burst duct over-pressurization event. Further, the study provides aircraft manufacturers with valuable insight into the impact that operating conditions and geometric configurations have on PRD performance and how the information can be used to assist future research and development of PRD design.

Integrated electrofluidic circuits: pressure sensing with analog and digital operation functionalities for microfluidics.

PubMed

Wu, Chueh-Yu; Lu, Jau-Ching; Liu, Man-Chi; Tung, Yi-Chung

2012-10-21

Microfluidic technology plays an essential role in various lab on a chip devices due to its desired advantages. An automated microfluidic system integrated with actuators and sensors can further achieve better controllability. A number of microfluidic actuation schemes have been well developed. In contrast, most of the existing sensing methods still heavily rely on optical observations and external transducers, which have drawbacks including: costly instrumentation, professional operation, tedious interfacing, and difficulties of scaling up and further signal processing. This paper reports the concept of electrofluidic circuits - electrical circuits which are constructed using ionic liquid (IL)-filled fluidic channels. The developed electrofluidic circuits can be fabricated using a well-developed multi-layer soft lithography (MSL) process with polydimethylsiloxane (PDMS) microfluidic channels. Electrofluidic circuits allow seamless integration of pressure sensors with analog and digital operation functions into microfluidic systems and provide electrical readouts for further signal processing. In the experiments, the analog operation device is constructed based on electrofluidic Wheatstone bridge circuits with electrical outputs of the addition and subtraction results of the applied pressures. The digital operation (AND, OR, and XOR) devices are constructed using the electrofluidic pressure controlled switches, and output electrical signals of digital operations of the applied pressures. The experimental results demonstrate the designed functions for analog and digital operations of applied pressures are successfully achieved using the developed electrofluidic circuits, making them promising to develop integrated microfluidic systems with capabilities of precise pressure monitoring and further feedback control for advanced lab on a chip applications.

Feasibility Test of a Pulse Modulated Pressurization System for a High Altitude Supersonic Target Vehicle Propulsion System.

DTIC Science & Technology

1976-11-01

pressure switch . The system was tested for stability of operation and accuracy of pressure control, using a High Altitude Supersonic Target (HAST...stable and accurate to approximately the deadband of the pressure switch used, 2 psi. (Author)

Transient Analysis of Pressurization and Pneumatic Subsystems of the X-34 Main Propulsion System

NASA Technical Reports Server (NTRS)

Hedayat, A.; Knight, K. C.; Chamption, R. H., Jr.; Kennedy, Jim W. (Technical Monitor)

2000-01-01

Transient models for the pressurization, vent/relief, and pneumatic subsystems of the X-34 Main Propulsion System are presented and simulation of their operation within prescribed requirements are provided. First, using ROCket Engine Transient Simulation (ROCETS) program, pressurization subsystem operation was simulated and helium requirements and the ullage thermodynamic condition within each propellant tank were calculated. Then, Overpressurization scenarios of propellant tanks and the response of vent/relief valves were evaluated using ROCETS simulation of simultaneous operation of the pressurization and vent/relief subsystems by incorporating the valves data into the model. Finally, the ROCETS simulation of in-flight operation of pneumatic subsystem predicted the overall helium consumption, Inter-Propellant Seal (IPS) purge flowrate and thermodynamic conditions, and Spin Start power.

Single module pressurized fuel cell turbine generator system

DOEpatents

George, Raymond A.; Veyo, Stephen E.; Dederer, Jeffrey T.

2001-01-01

A pressurized fuel cell system (10), operates within a common pressure vessel (12) where the system contains fuel cells (22), a turbine (26) and a generator (98) where preferably, associated oxidant inlet valve (52), fuel inlet valve (56) and fuel cell exhaust valve (42) are outside the pressure vessel.

Combined Pressure and Thermal Window System for Space Vehicles

NASA Technical Reports Server (NTRS)

Svartstrom, Kirk Nils (Inventor)

2015-01-01

A window system for a vehicle comprising a pressure and thermal window pane, a seal system, and a retainer system. The pressure and thermal window pane may be configured to provide desired pressure protection and desired thermal protection when exposed to an environment around the vehicle during operation of the vehicle. The pressure and thermal window pane may have a desired ductility. The seal system may be configured to contact the pressure and thermal window pane to seal the pressure and thermal window pane. The retainer system may be configured to hold the seal system and the pressure and thermal window pane.

Combined Pressure and Thermal Window System for Space Vehicles

NASA Technical Reports Server (NTRS)

Svartstrom, Kirk Nils (Inventor)

2017-01-01

A window system for a vehicle comprising a pressure and thermal window pane, a seal system, and a retainer system. The pressure and thermal window pane may be configured to provide desired pressure protection and desired thermal protection when exposed to an environment around the vehicle during operation of the vehicle. The pressure and thermal window pane may have a desired ductility. The seal system may be configured to contact the pressure and thermal window pane to seal the pressure and thermal window pane. The retainer system may be configured to hold the seal system and the pressure and thermal window pane.

System Design of a Natural Gas PEM Fuel Cell Power Plant for Buildings

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

Joe Ferrall, Tim Rehg, Vesna Stanic

2000-09-30

The following conclusions are made based on this analysis effort: (1) High-temperature PEM data are not available; (2) Stack development effort for Phase II is required; (3) System results are by definition preliminary, mostly due to the immaturity of the high-temperature stack; other components of the system are relatively well defined; (4) The Grotthuss conduction mechanism yields the preferred system characteristics; the Grotthuss conduction mechanism is also much less technically mature than the vehicle mechanism; (5) Fuel processor technology is available today and can be procured for Phase II (steam or ATR); (6) The immaturity of high-temperature membrane technology requiresmore » that a robust system design be developed in Phase II that is capable of operating over a wide temperature and pressure range - (a) Unpressurized or Pressurized PEM (Grotthuss mechanism) at 140 C, Highest temperature most favorable, Lowest water requirement most favorable, Pressurized recommended for base loaded operation, Unpressurized may be preferred for load following; (b) Pressurized PEM (vehicle mechanism) at about 100 C, Pressure required for saturation, Fuel cell technology currently available, stack development required. The system analysis and screening evaluation resulted in the identification of the following components for the most promising system: (1) Steam reforming fuel processor; (2) Grotthuss mechanism fuel cell stack operating at 140 C; (3) Means to deliver system waste heat to a cogeneration unit; (4) Pressurized system utilizing a turbocompressor for a base-load power application. If duty cycling is anticipated, the benefits of compression may be offset due to complexity of control. In this case (and even in the base loaded case), the turbocompressor can be replaced with a blower for low-pressure operation.« less

Combined cold compressor/ejector helium refrigerator

DOEpatents

Brown, D.P.

1984-06-05

A refrigeration apparatus having an ejector operatively connected with a cold compressor to form a two-stage pumping system. This pumping system is used to lower the pressure, and thereby the temperature of a bath of boiling refrigerant (helium). The apparatus as thus arranged and operated has substantially improved operating efficiency when compared to other processes or arrangements for achieving a similar low pressure.

Combined cold compressor/ejector helium refrigerator

DOEpatents

Brown, Donald P.

1985-01-01

A refrigeration apparatus having an ejector operatively connected with a cold compressor to form a two-stage pumping system. This pumping system is used to lower the pressure, and thereby the temperature of a bath of boiling refrigerant (helium). The apparatus as thus arranged and operated has substantially improved operating efficiency when compared to other processes or arrangements for achieving a similar low pressure.

Reactor core isolation cooling system

DOEpatents

Cooke, F.E.

1992-12-08

A reactor core isolation cooling system includes a reactor pressure vessel containing a reactor core, a drywell vessel, a containment vessel, and an isolation pool containing an isolation condenser. A turbine is operatively joined to the pressure vessel outlet steamline and powers a pump operatively joined to the pressure vessel feedwater line. In operation, steam from the pressure vessel powers the turbine which in turn powers the pump to pump makeup water from a pool to the feedwater line into the pressure vessel for maintaining water level over the reactor core. Steam discharged from the turbine is channeled to the isolation condenser and is condensed therein. The resulting heat is discharged into the isolation pool and vented to the atmosphere outside the containment vessel for removing heat therefrom. 1 figure.

Reactor core isolation cooling system

DOEpatents

Cooke, Franklin E.

1992-01-01

A reactor core isolation cooling system includes a reactor pressure vessel containing a reactor core, a drywell vessel, a containment vessel, and an isolation pool containing an isolation condenser. A turbine is operatively joined to the pressure vessel outlet steamline and powers a pump operatively joined to the pressure vessel feedwater line. In operation, steam from the pressure vessel powers the turbine which in turn powers the pump to pump makeup water from a pool to the feedwater line into the pressure vessel for maintaining water level over the reactor core. Steam discharged from the turbine is channeled to the isolation condenser and is condensed therein. The resulting heat is discharged into the isolation pool and vented to the atmosphere outside the containment vessel for removing heat therefrom.

Evaluation of fuel preparation systems for lean premixing-prevaporizing combustors

NASA Technical Reports Server (NTRS)

Dodds, W. J.; Ekstedt, E. E.

1985-01-01

A series of experiments was carried out in order to produce design data for a premixing prevaporizing fuel-air mixture preparation system for aircraft gas turbine engine combustors. The fuel-air mixture uniformity of four different system design concepts was evaluated over a range of conditions representing the cruise operation of a modern commercial turbofan engine. Operating conditions including pressure, temperature, fuel-to-air ratio, and velocity, exhibited no clear effect on mixture uniformity of systems using pressure-atomizing fuel nozzles and large-scale mixing devices. However, the performance of systems using atomizing fuel nozzles and large-scale mixing devices was found to be sensitive to operating conditions. Variations in system design variables were also evaluated and correlated. Mixing uniformity was found to improve with system length, pressure drop, and the number of fuel injection points per unit area. A premixing system capable of providing mixing uniformity to within 15 percent over a typical range of cruise operating conditions is demonstrated.

Low pressure electrospray ionization system and process for effective transmission of ions

DOEpatents

Tang, Keqi [Richland, WA; Page, Jason S [Kennewick, WA; Kelly, Ryan T [West Richland, WA; Smith, Richard D [Richland, WA

2012-05-08

Systems and methods that provide up to complete transmission of ions between coupled stages with low effective ion losses. An "interfaceless" electrospray ionization system is further described that operates an electrospray at a reduced pressure such that standard electrospray sample solutions can be directly sprayed into an electrodynamic ion funnel which provides ion focusing and transmission of ions into a mass analyzer. Furthermore, chambers maintained at different pressures can allow for more optimal operating conditions for an electrospray emitter and an ion guide.

Engineering concepts for inflatable Mars surface greenhouses

NASA Technical Reports Server (NTRS)

Hublitz, I.; Henninger, D. L.; Drake, B. G.; Eckart, P.

2004-01-01

A major challenge of designing a bioregenerative life support system for Mars is the reduction of the mass, volume, power, thermal and crew-time requirements. Structural mass of the greenhouse could be saved by operating the greenhouse at low atmospheric pressure. This paper investigates the feasibility of this concept. The method of equivalent system mass is used to compare greenhouses operated at high atmospheric pressure to greenhouses operated at low pressure for three different lighting methods: natural, artificial and hybrid lighting. c2004 COSPAR. Published by Elsevier Ltd. All rights reserved.

Engineering concepts for inflatable Mars surface greenhouses.

PubMed

Hublitz, I; Henninger, D L; Drake, B G; Eckart, P

2004-01-01

A major challenge of designing a bioregenerative life support system for Mars is the reduction of the mass, volume, power, thermal and crew-time requirements. Structural mass of the greenhouse could be saved by operating the greenhouse at low atmospheric pressure. This paper investigates the feasibility of this concept. The method of equivalent system mass is used to compare greenhouses operated at high atmospheric pressure to greenhouses operated at low pressure for three different lighting methods: natural, artificial and hybrid lighting. c2004 COSPAR. Published by Elsevier Ltd. All rights reserved.

Subsystem Analysis/Optimization for the X-34 Main Propulsion System

NASA Technical Reports Server (NTRS)

McDonald, J. P.; Hedayat, A.; Brown, T. M.; Knight, K. C.; Champion, R. H., Jr.

1998-01-01

The Orbital Sciences Corporation X-34 vehicle demonstrates technologies and operations key to future reusable launch vehicles. The general flight performance goal of this unmanned rocket plane is Mach 8 flight at an altitude of 250,000 feet. The Main Propulsion System (MPS) supplies liquid propellants to the main engine, which provides the primary thrust for attaining mission goals. Major MPS design and operational goals are aircraft-like ground operations, quick turnaround between missions, and low initial/operational costs. Analyses related to optimal MPS subsystem design are reviewed in this paper. A pressurization system trade weighs maintenance/reliability concerns against those for safety in a comparison of designs using pressure regulators versus orifices to control pressurant flow. A propellant dump/feed system analysis weighs the issues of maximum allowable vehicle landing weight, trajectory, and MPS complexity to arrive at a final configuration for propellant dump/feed systems.

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...

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

Glass, George

Pressure Safety Orientation (course #769) introduces workers at Los Alamos National Laboratory (LANL) to the Laboratory Pressure Safety Program and to pressure-related hazards. This course also affords a hands-on exercise involving the assembly of a simple pressure system. This course is required for all LANL personnel who work on or near pressure systems and are exposed to pressure-related hazards. These personnel include pressure-system engineers, designers, fabricators, installers, operators, inspectors, maintainers, and others who work with pressurized fluids and may be exposed to pressure-related hazards.

14 CFR 29.1435 - Hydraulic systems.

Code of Federal Regulations, 2011 CFR

2011-01-01

... hydraulic system must be designed to withstand pressures sufficiently greater than those prescribed in... must be means to indicate the pressure in each main hydraulic power system. (4) There must be means to... detrimental transient (surge) pressures during operation must be considered. (5) Each hydraulic line, fitting...

14 CFR 29.1435 - Hydraulic systems.

Code of Federal Regulations, 2012 CFR

2012-01-01

... hydraulic system must be designed to withstand pressures sufficiently greater than those prescribed in... must be means to indicate the pressure in each main hydraulic power system. (4) There must be means to... detrimental transient (surge) pressures during operation must be considered. (5) Each hydraulic line, fitting...

Oil field management system

DOEpatents

Fincke, James R.

2003-09-23

Oil field management systems and methods for managing operation of one or more wells producing a high void fraction multiphase flow. The system includes a differential pressure flow meter which samples pressure readings at various points of interest throughout the system and uses pressure differentials derived from the pressure readings to determine gas and liquid phase mass flow rates of the high void fraction multiphase flow. One or both of the gas and liquid phase mass flow rates are then compared with predetermined criteria. In the event such mass flow rates satisfy the predetermined criteria, a well control system implements a correlating adjustment action respecting the multiphase flow. In this way, various parameters regarding the high void fraction multiphase flow are used as control inputs to the well control system and thus facilitate management of well operations.

Forward osmosis membrane modular configurations for osmotic dilution of seawater by forward osmosis and reverse osmosis hybrid system.

PubMed

Kim, Jung Eun; Phuntsho, Sherub; Ali, Syed Muztuza; Choi, Joon Young; Shon, Ho Kyong

2018-01-01

This study evaluates various options for full-scale modular configuration of forward osmosis (FO) process for osmotic dilution of seawater using wastewater for simultaneous desalination and water reuse through FO-reverse osmosis (RO) hybrid system. Empirical relationship obtained from one FO membrane element operation was used to simulate the operational performances of different FO module configurations. The main limiting criteria for module operation is to always maintain the feed pressure higher than the draw pressure throughout the housing module for safe operation without affecting membrane integrity. Experimental studies under the conditions tested in this study show that a single membrane housing cannot accommodate more than four elements as the draw pressure exceeds the feed pressure. This then indicates that a single stage housing with eight elements is not likely to be practical for safe FO operation. Hence, six different FO modular configurations were proposed and simulated. A two-stage FO configuration with multiple housings (in parallel) in the second stage using same or larger spacer thickness reduces draw pressure build-up as the draw flow rates are reduced to half in the second stage thereby allowing more than four elements in the second stage housing. The loss of feed pressure (pressure drop) and osmotic driving force in the second stage are compensated by operating under the pressure assisted osmosis (PAO) mode, which helps enhance permeate flux and maintains positive pressure differences between the feed and draw chamber. The PAO energy penalty is compensated by enhanced permeate throughput, reduced membrane area, and plant footprint. The contribution of FO/PAO to total energy consumption was not significant compared to post RO desalination (90%) indicating that the proposed two-stage FO modular configuration is one way of making the FO full-scale operation practical for FO-RO hybrid system. Copyright © 2017 Elsevier Ltd. All rights reserved.

Demonstration of a Packaged Capacitive Pressure Sensor System Suitable for Jet Turbofan Engine Health Monitoring

NASA Technical Reports Server (NTRS)

Scardelletti, Maximilian C.; Jordan, Jennifer L.; Meredith, Roger D.; Harsh, Kevin; Pilant, Evan; Usrey, Michael W.; Beheim, Glenn M.; Hunter, Gary W.; Zorman, Christian A.

2016-01-01

In this paper, the development and characterization of a packaged pressure sensor system suitable for jet engine health monitoring is demonstrated. The sensing system operates from 97 to 117 MHz over a pressure range from 0 to 350 psi and a temperature range from 25 to 500 deg. The sensing system consists of a Clapp-type oscillator that is fabricated on an alumina substrate and is comprised of a Cree SiC MESFET, MIM capacitors, a wire-wound inductor, chip resistors and a SiCN capacitive pressure sensor. The pressure sensor is located in the LC tank circuit of the oscillator so that a change in pressure causes a change in capacitance, thus changing the resonant frequency of the sensing system. The chip resistors, wire-wound inductors and MIM capacitors have all been characterized at temperature and operational frequency, and perform with less than 5% variance in electrical performance. The measured capacitive pressure sensing system agrees very well with simulated results. The packaged pressure sensing system is specifically designed to measure the pressure on a jet turbofan engine. The packaged system can be installed by way of borescope plug adaptor fitted to a borescope port exposed to the gas path of a turbofan engine.

Stability analysis of coupled torsional vibration and pressure in oilwell drillstring system

NASA Astrophysics Data System (ADS)

Toumi, S.; Beji, L.; Mlayeh, R.; Abichou, A.

2018-01-01

To address security issues in oilwell drillstring system, the drilling operation handling which is in generally not autonomous but ensured by an operator may be drill bit destructive or fatal for the machine. To control of stick-slip phenomenon, the drillstring control at the right speed taking only the drillstring vibration is not sufficient as the mud dynamics and the pressure change around the drill pipes cannot be neglected. A coupled torsional vibration and pressure model is presented, and the well-posedness problem is addressed. As a Partial Differential Equation-Ordinary Differential Equation (PDE-ODE) coupled system, and in order to maintain a non destructive downhole pressure, we investigate the control stability with and without the damping term in the wave PDE. In terms of, the torsional variable, the downhole pressure, and the annulus pressure, the coupled system equilibrium is shown to be exponentially stable.

The experimental study of matching between centrifugal compressor impeller and diffuser

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

Tamaki, H.; Nakao, H.; Saito, M.

1999-01-01

the centrifugal compressor for a marine use turbocharger with its design pressure ratio of 3.2 was tested with a vaneless diffuser and various vaned diffusers. Vaned diffusers were chosen to cover impeller operating range as broad as possible. The analysis of the static pressure ratio in the impeller and the diffusing system, consisting of the diffuser and scroll, showed that there were four possible combinations of characteristics of impeller pressure ratio and diffusing system pressure ratio. The flow rate, Q{sub P}, where the impeller achieved maximum static pressure ratio, was surge flow rate of the centrifugal compressor determined by themore » critical flow rate. In order to operate the compressor at a rate lower than Q{sub P}, the diffusing system, whose pressure recovery factor was steep negative slope near Q{sub P}, was needed. When the diffuser throat area was less than a certain value, the compressor efficiency deteriorated; however, the compressor stage pressure ratio was almost constant. In this study, by reducing the diffuser throat area, the compressor could be operated at a flow rate less than 40% of its design flow rate. Analysis of the pressure ratio in the impeller and diffusing systems at design and off-design speeds showed that the irregularities in surge line occurred when the component that controlled the negative slope on the compressor stage pressure ratio changed.« less

A system for automatic analysis of blood pressure data for digital computer entry

NASA Technical Reports Server (NTRS)

Miller, R. L.

1972-01-01

Operation of automatic blood pressure data system is described. Analog blood pressure signal is analyzed by three separate circuits, systolic, diastolic, and cycle defect. Digital computer output is displayed on teletype paper tape punch and video screen. Illustration of system is included.

Hydraulic model of the proposed Water Recovery and Management system for Space Station Freedom

NASA Technical Reports Server (NTRS)

Martin, Charles E.; Bacskay, Allen S.

1991-01-01

A model of the Water Recovery and Management (WRM) system utilizing SINDA '85/FLUINT to determine its hydraulic operation characteristics, and to verify the design flow and pressure drop parameters is presented. The FLUINT analysis package is employed in the model to determine the flow and pressure characteristics when each of the different loop components is operational and contributing to the overall flow pattern. The water is driven in each loop by storage tanks pressurized with cabin air, and is routed through the system to the desired destination.

Systems and methods for detecting a flame in a fuel nozzle of a gas turbine

DOEpatents

Kraemer, Gilbert Otto; Storey, James Michael; Lipinski, John; Mestroni, Julio Enrique; Williamson, David Lee; Marshall, Jason Randolph; Krull, Anthony

2013-05-07

A system may detect a flame about a fuel nozzle of a gas turbine. The gas turbine may have a compressor and a combustor. The system may include a first pressure sensor, a second pressure sensor, and a transducer. The first pressure sensor may detect a first pressure upstream of the fuel nozzle. The second pressure sensor may detect a second pressure downstream of the fuel nozzle. The transducer may be operable to detect a pressure difference between the first pressure sensor and the second pressure sensor.

30 CFR 250.447 - When must I pressure test the BOP system?

Code of Federal Regulations, 2013 CFR

2013-07-01

... THE INTERIOR OFFSHORE OIL AND GAS AND SULPHUR OPERATIONS IN THE OUTER CONTINENTAL SHELF Oil and Gas Drilling Operations Blowout Preventer (bop) System Requirements § 250.447 When must I pressure test the BOP... BOP, and drill-string safety valve): (a) When installed; (b) Before 14 days have elapsed since your...

30 CFR 250.447 - When must I pressure test the BOP system?

Code of Federal Regulations, 2012 CFR

2012-07-01

... THE INTERIOR OFFSHORE OIL AND GAS AND SULPHUR OPERATIONS IN THE OUTER CONTINENTAL SHELF Oil and Gas Drilling Operations Blowout Preventer (bop) System Requirements § 250.447 When must I pressure test the BOP... BOP, and drill-string safety valve): (a) When installed; (b) Before 14 days have elapsed since your...

30 CFR 250.447 - When must I pressure test the BOP system?

Code of Federal Regulations, 2014 CFR

2014-07-01

... THE INTERIOR OFFSHORE OIL AND GAS AND SULPHUR OPERATIONS IN THE OUTER CONTINENTAL SHELF Oil and Gas Drilling Operations Blowout Preventer (bop) System Requirements § 250.447 When must I pressure test the BOP... BOP, and drill-string safety valve): (a) When installed; (b) Before 14 days have elapsed since your...

30 CFR 250.447 - When must I pressure test the BOP system?

Code of Federal Regulations, 2010 CFR

2010-07-01

... OIL AND GAS AND SULPHUR OPERATIONS IN THE OUTER CONTINENTAL SHELF Oil and Gas Drilling Operations... pressure test your BOP system (this includes the choke manifold, kelly valves, inside BOP, and drill-string... performance warrant; and (c) Before drilling out each string of casing or a liner. The District Manager may...

30 CFR 250.447 - When must I pressure test the BOP system?

Code of Federal Regulations, 2011 CFR

2011-07-01

..., DEPARTMENT OF THE INTERIOR OFFSHORE OIL AND GAS AND SULPHUR OPERATIONS IN THE OUTER CONTINENTAL SHELF Oil and Gas Drilling Operations Blowout Preventer (bop) System Requirements § 250.447 When must I pressure... valves, inside BOP, and drill-string safety valve): (a) When installed; (b) Before 14 days have elapsed...

49 CFR 178.345-10 - Pressure relief.

Code of Federal Regulations, 2010 CFR

2010-10-01

... applicable individual specification. The pressure and vacuum relief system must be designed to operate and... resulting from loading, unloading, or from heating and cooling of lading. Pressure relief systems are not required to conform to the ASME Code. (b) Type and construction of relief systems and devices. (1) Each...

40 CFR 63.3556 - How do I establish the emission capture system and add-on control device operating limits during...

Code of Federal Regulations, 2014 CFR

2014-07-01

... capture system and add-on control device operating limits during the performance test? 63.3556 Section 63... system and add-on control device operating limits during the performance test? During the performance... of key parameters of the valve operating system (e.g., solenoid valve operation, air pressure...

40 CFR 63.3546 - How do I establish the emission capture system and add-on control device operating limits during...

Code of Federal Regulations, 2013 CFR

2013-07-01

... system and add-on control device operating limits during the performance test? 63.3546 Section 63.3546... of key parameters of the valve operating system (e.g., solenoid valve operation, air pressure... minimum operating limit for that specific capture device or system of multiple capture devices. The...

40 CFR 63.3546 - How do I establish the emission capture system and add-on control device operating limits during...

Code of Federal Regulations, 2014 CFR

2014-07-01

... capture system and add-on control device operating limits during the performance test? 63.3546 Section 63... of key parameters of the valve operating system (e.g., solenoid valve operation, air pressure... minimum operating limit for that specific capture device or system of multiple capture devices. The...

40 CFR 63.3546 - How do I establish the emission capture system and add-on control device operating limits during...

Code of Federal Regulations, 2012 CFR

2012-07-01

... capture system and add-on control device operating limits during the performance test? 63.3546 Section 63... of key parameters of the valve operating system (e.g., solenoid valve operation, air pressure... minimum operating limit for that specific capture device or system of multiple capture devices. The...

40 CFR 63.3556 - How do I establish the emission capture system and add-on control device operating limits during...

Code of Federal Regulations, 2012 CFR

2012-07-01

... capture system and add-on control device operating limits during the performance test? 63.3556 Section 63... system and add-on control device operating limits during the performance test? During the performance... of key parameters of the valve operating system (e.g., solenoid valve operation, air pressure...

Numerical study on criteria for design and operation of water curtain system in underground oil storage cavern using site descriptive fracture networks

NASA Astrophysics Data System (ADS)

Moon, Jiwon; Yeo, In Wook

2013-04-01

Underground unlined caverns have been constructed in fractured rocks to stockpile oil and petroleum products, where they are hydraulically contained by natural groundwater pressure. However, for the case that natural groundwater pressure is not maintained at the required level, water curtain boreholes, through which water is injected, are often constructed above the cavern as engineering barrier to secure water pressure enough to overwhelm the operational pressure of the cavern. For secure containment of oil and petroleum products inside the cavern, it is essential to keep water pressure around the cavern higher than operational pressure of the cavern using either natural groundwater pressure or engineering barrier. In the Republic of Korea, a number of underground stockpile bases are being operated by Korea National Oil Corporation (KNOC) and private companies, most of which have water curtain system. The criterion that KNOC adopts for water curtain system design and operation such as the vertical distance from the cavern and operational injection rate is based on the Åberg hypothesis that the vertical hydraulic gradient should be larger than one. The criterion has been used for maintaining oil storage cavern without its thorough review. In this study, systematic numerical works have been done for reviewing the Åberg criterion. As groundwater predominantly takes places through fractures in underground caverns, discrete fracture modeling approach is essential for this study. Fracture data, obtained from boreholes drilled at the stage of site investigation at the Yeosu stockpile base in Korea, were statistically analyzed in terms of orientation and intensity, which were used to generate the site descriptive three dimensional fracture networks. Then, groundwater flow modeling has been carried out for the fracture networks. Constant head boundaries were applied along the circumference of the cavern and water curtain boreholes. Main flow channel and hydraulic connectivity between water curtain boreholes and the caverns have been identified, along which hydraulic heads are monitored to find out whether the required hydraulic pressure is maintained around the cavern. The flow modeling has been repeatedly carried out at different constant head boundary conditions to create the criterion for the optimal operation of water curtain system.

A temperature and pressure controlled calibration system for pressure sensors

NASA Technical Reports Server (NTRS)

Chapman, John J.; Kahng, Seun K.

1989-01-01

A data acquisition and experiment control system capable of simulating temperatures from -184 to +220 C and pressures either absolute or differential from 0 to 344.74 kPa is developed to characterize silicon pressure sensor response to temperature and pressure. System software is described that includes sensor data acquisition, algorithms for numerically derived thermal offset and sensitivity correction, and operation of the environmental chamber and pressure standard. This system is shown to be capable of computer interfaced cryogenic testing to within 1 C and 34.47 Pa of single channel or multiplexed arrays of silicon pressure sensors.

A thermodynamic approach for selecting operating conditions in the design of reversible solid oxide cell energy systems

NASA Astrophysics Data System (ADS)

Wendel, Christopher H.; Kazempoor, Pejman; Braun, Robert J.

2016-01-01

Reversible solid oxide cell (ReSOC) systems are being increasingly considered for electrical energy storage, although much work remains before they can be realized, including cell materials development and system design optimization. These systems store electricity by generating a synthetic fuel in electrolysis mode and subsequently recover electricity by electrochemically oxidizing the stored fuel in fuel cell mode. System thermal management is improved by promoting methane synthesis internal to the ReSOC stack. Within this strategy, the cell-stack operating conditions are highly impactful on system performance and optimizing these parameters to suit both operating modes is critical to achieving high roundtrip efficiency. Preliminary analysis shows the thermoneutral voltage to be a useful parameter for analyzing ReSOC systems and the focus of this study is to quantitatively examine how it is affected by ReSOC operating conditions. The results reveal that the thermoneutral voltage is generally reduced by increased pressure, and reductions in temperature, fuel utilization, and hydrogen-to-carbon ratio. Based on the thermodynamic analysis, many different combinations of these operating conditions are expected to promote efficient energy storage. Pressurized systems can achieve high efficiency at higher temperature and fuel utilization, while non-pressurized systems may require lower stack temperature and suffer from reduced energy density.

Automated analysis of blood pressure measurements (Korotkov sound)

NASA Technical Reports Server (NTRS)

Golden, D. P.; Hoffler, G. W.; Wolthuis, R. A.

1972-01-01

Automatic system for noninvasive measurements of arterial blood pressure is described. System uses Korotkov sound processor logic ratios to identify Korotkov sounds. Schematic diagram of system is provided to show components and method of operation.

Pressure-Transducer Simulator

NASA Technical Reports Server (NTRS)

Simon, Richard A.

1987-01-01

Simulation circuit operates under remote, automatic, or manual control to produce electrical outputs similar to pressure transducer. Specific circuit designed for simulations of Space Shuttle main engine. General circuit concept adaptable to other simulation and control systems involving several operating modes. Switches and amplifiers respond to external control signals and panel control settings to vary differential excitation of resistive bridge. Output voltage or passive terminal resistance made to equal pressure transducer in any of four operating modes.

The 12-foot pressure wind tunnel restoration project model support systems

NASA Technical Reports Server (NTRS)

Sasaki, Glen E.

1992-01-01

The 12 Foot Pressure Wind Tunnel is a variable density, low turbulence wind tunnel that operates at subsonic speeds, and up to six atmospheres total pressure. The restoration of this facility is of critical importance to the future of the U.S. aerospace industry. As part of this project, several state of the art model support systems are furnished to provide an optimal balance between aerodynamic and operational efficiency parameters. Two model support systems, the Rear Strut Model Support, and the High Angle of Attack Model Support are discussed. This paper covers design parameters, constraints, development, description, and component selection.

Effect of reference conditions on flow rate, modifier fraction and retention in supercritical fluid chromatography.

PubMed

De Pauw, Ruben; Shoykhet Choikhet, Konstantin; Desmet, Gert; Broeckhoven, Ken

2016-08-12

When using compressible mobile phases such as fluidic CO2, the density, the volumetric flow rates and volumetric fractions are pressure dependent. The pressure and temperature definition of these volumetric parameters (referred to as the reference conditions) may alter between systems, manufacturers and operating conditions. A supercritical fluid chromatography system was modified to operate in two modes with different definition of the eluent delivery parameters, referred to as fixed and variable mode. For the variable mode, the volumetric parameters are defined with reference to the pump operating pressure and actual pump head temperature. These conditions may vary when, e.g. changing the column length, permeability, flow rate, etc. and are thus variable reference conditions. For the fixed mode, the reference conditions were set at 150bar and 30°C, resulting in a mass flow rate and mass fraction of modifier definition which is independent of the operation conditions. For the variable mode, the mass flow rate of carbon dioxide increases with system pump operating pressure, decreasing the fraction of modifier. Comparing the void times and retention factor shows that the deviation between the two modes is almost independent of modifier percentage, but depends on the operating pressure. Recalculating the set volumetric fraction of modifier to the mass fraction results in the same retention behaviour for both modes. This shows that retention in SFC can be best modelled using the mass fraction of modifier. The fixed mode also simplifies method scaling as it only requires matching average column pressure. Copyright © 2016 Elsevier B.V. All rights reserved.

Reactor water cleanup system

DOEpatents

Gluntz, Douglas M.; Taft, William E.

1994-01-01

A reactor water cleanup system includes a reactor pressure vessel containing a reactor core submerged in reactor water. First and second parallel cleanup trains are provided for extracting portions of the reactor water from the pressure vessel, cleaning the extracted water, and returning the cleaned water to the pressure vessel. Each of the cleanup trains includes a heat exchanger for cooling the reactor water, and a cleaner for cleaning the cooled reactor water. A return line is disposed between the cleaner and the pressure vessel for channeling the cleaned water thereto in a first mode of operation. A portion of the cooled water is bypassed around the cleaner during a second mode of operation and returned through the pressure vessel for shutdown cooling.

Pressure system recertification at NASA-Langley Research Center

NASA Technical Reports Server (NTRS)

Hudson, C. M.; Ramsey, J. W., Jr.

1983-01-01

Langley Research Center pressure systems are being recertified to ensure safe operation of these systems. The procedures for recertifying these pressure systems are reviewed. Generally, the analysis and inspection requirements outlined in the appropriate national consensus codes are followed. In some instances where the requirements of these codes are not met. The systems are analyzed further, repaired, modified and/or tested to demonstrate their structural integrity.

46 CFR 154.1836 - Vapor venting as a means of cargo tank pressure and temperature control.

Code of Federal Regulations, 2013 CFR

2013-10-01

... temperature control. 154.1836 Section 154.1836 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY... LIQUEFIED GASES Operations § 154.1836 Vapor venting as a means of cargo tank pressure and temperature... cargo pressure and temperature control system under §§ 154.701 through 154.709 is operating and that...

46 CFR 154.1836 - Vapor venting as a means of cargo tank pressure and temperature control.

Code of Federal Regulations, 2014 CFR

2014-10-01

... temperature control. 154.1836 Section 154.1836 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY... LIQUEFIED GASES Operations § 154.1836 Vapor venting as a means of cargo tank pressure and temperature... cargo pressure and temperature control system under §§ 154.701 through 154.709 is operating and that...

46 CFR 154.1836 - Vapor venting as a means of cargo tank pressure and temperature control.

Code of Federal Regulations, 2012 CFR

2012-10-01

... temperature control. 154.1836 Section 154.1836 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY... LIQUEFIED GASES Operations § 154.1836 Vapor venting as a means of cargo tank pressure and temperature... cargo pressure and temperature control system under §§ 154.701 through 154.709 is operating and that...

46 CFR 154.1836 - Vapor venting as a means of cargo tank pressure and temperature control.

Code of Federal Regulations, 2010 CFR

2010-10-01

... temperature control. 154.1836 Section 154.1836 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY... LIQUEFIED GASES Operations § 154.1836 Vapor venting as a means of cargo tank pressure and temperature... cargo pressure and temperature control system under §§ 154.701 through 154.709 is operating and that...

46 CFR 154.1836 - Vapor venting as a means of cargo tank pressure and temperature control.

Code of Federal Regulations, 2011 CFR

2011-10-01

... temperature control. 154.1836 Section 154.1836 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY... LIQUEFIED GASES Operations § 154.1836 Vapor venting as a means of cargo tank pressure and temperature... cargo pressure and temperature control system under §§ 154.701 through 154.709 is operating and that...

Optimal Design and Operation of Permanent Irrigation Systems

NASA Astrophysics Data System (ADS)

Oron, Gideon; Walker, Wynn R.

1981-01-01

Solid-set pressurized irrigation system design and operation are studied with optimization techniques to determine the minimum cost distribution system. The principle of the analysis is to divide the irrigation system into subunits in such a manner that the trade-offs among energy, piping, and equipment costs are selected at the minimum cost point. The optimization procedure involves a nonlinear, mixed integer approach capable of achieving a variety of optimal solutions leading to significant conclusions with regard to the design and operation of the system. Factors investigated include field geometry, the effect of the pressure head, consumptive use rates, a smaller flow rate in the pipe system, and outlet (sprinkler or emitter) discharge.

Automated Cryocooler Monitor and Control System

NASA Technical Reports Server (NTRS)

Britcliffe, Michael J.; Hanscon, Theodore R.; Fowler, Larry E.

2011-01-01

A system was designed to automate cryogenically cooled low-noise amplifier systems used in the NASA Deep Space Network. It automates the entire operation of the system including cool-down, warm-up, and performance monitoring. The system is based on a single-board computer with custom software and hardware to monitor and control the cryogenic operation of the system. The system provides local display and control, and can be operated remotely via a Web interface. The system controller is based on a commercial single-board computer with onboard data acquisition capability. The commercial hardware includes a microprocessor, an LCD (liquid crystal display), seven LED (light emitting diode) displays, a seven-key keypad, an Ethernet interface, 40 digital I/O (input/output) ports, 11 A/D (analog to digital) inputs, four D/A (digital to analog) outputs, and an external relay board to control the high-current devices. The temperature sensors used are commercial silicon diode devices that provide a non-linear voltage output proportional to temperature. The devices are excited with a 10-microamp bias current. The system is capable of monitoring and displaying three temperatures. The vacuum sensors are commercial thermistor devices. The output of the sensors is a non-linear voltage proportional to vacuum pressure in the 1-Torr to 1-millitorr range. Two sensors are used. One measures the vacuum pressure in the cryocooler and the other the pressure at the input to the vacuum pump. The helium pressure sensor is a commercial device that provides a linear voltage output from 1 to 5 volts, corresponding to a gas pressure from 0 to 3.5 MPa (approx. = 500 psig). Control of the vacuum process is accomplished with a commercial electrically operated solenoid valve. A commercial motor starter is used to control the input power of the compressor. The warm-up heaters are commercial power resistors sized to provide the appropriate power for the thermal mass of the particular system, and typically provide 50 watts of heat. There are four basic operating modes. "Cool " mode commands the system to cool to normal operating temperature. "Heat " mode is used to warm the device to a set temperature near room temperature. "Pump " mode is a maintenance function that allows the vacuum system to be operated alone to remove accumulated contaminants from the vacuum area. In "Off " mode, no power is applied to the system.

A prospective double-blinded randomized controlled trial comparing systemic stress response in Laparoascopic cholecystectomy between low-pressure and standard-pressure pneumoperitoneum.

PubMed

Shoar, Saeed; Naderan, Mohammad; Ebrahimpour, Hossein; Soroush, Ahmadreza; Nasiri, Shirzad; Movafegh, Ali; Khorgami, Zhamak

2016-04-01

Laparoscopic cholecystectomy (LC) has become the gold-standard treatment for gallstone diseases. However, despite huge reduction in operative injury, systemic stress response remains high. This randomized controlled trial (RCT) aimed to compare systemic stress response between 2 different techniques of CO2 pneumoperitoneum. Trough a prospective, double-blinded RCT, serum levels of cortisol, adrenaline, glucose, and C-reactive protein (CRP) were compared between the two groups consisted of 50 patients undergoing LC under low-pressure and standard-pressure CO2 pneimoperitoneum. A total of fifty patients undergoing LC were equally assigned to 2 groups of twenty five patients. Average age was 48 ± 13.8 years (range, 19-74 years). Operative time was similar between standard-pressure group (47.8 ± 16.8 min) and low-pressure group (53.6 ± 25.1). Moreover, intra-operative IV volume administration and urine output did not differ significantly between the 2 groups (p > 0.05). Although the average heart rate and mean arterial pressure were slightly higher in a standard-pressure group compared with a low-pressure group, serial measurements of these parameters were statistically similar between the 2 groups. Serial changes of serum levels of cortisol, glucose, adrenaline, and CRP were compared between surgery day, postoperative 6-h and 1st postoperative day, which did not differ significantly between the standard-pressure and the low-pressure groups (p > 0.05). Our study did not reveal any alteration in systemic stress response with reduction in intra-abdominal pressure of pneumoperitoneum in LC. RCT REGISTRATION: irct.ir ID: IRCT201110072982N5. Copyright © 2016 IJS Publishing Group Limited. Published by Elsevier Ltd. All rights reserved.

Johnson Space Center's regenerative life support systems test bed

NASA Technical Reports Server (NTRS)

Henninger, Donald L.; Tri, Terry O.; Barta, Daniel J.; Stahl, Randal S.

1991-01-01

The Regenerative Life Support System (RLSS) Test Bed at NASA's Johnson Space Center is an atmospherically closed, controlled environment facility for the evaluation of regenerative life support systems using higher plants in conjunction with physicochemical life support systems. When completed, the facility will be comprised of two large scale plant growth chambers, each with approximately 10 m(exp 2) growing area. One of the two chambers, the Variable Pressure Growth Chamber (VPGC), will be capable of operating at lower atmospheric pressures to evaluate a range of environments that may be used in Lunar or Martian habitats; the other chamber, the Ambient Pressure Growth Chamber (APGC) will operate at ambient atmospheric pressure. The root zone in each chamber will be configurable for hydroponic or solid state media systems. Research will focus on: (1) in situ resource utilization for CELSS systems, in which simulated lunar soils will be used in selected crop growth studies; (2) integration of biological and physicochemical air and water revitalization systems; (3) effect of atmospheric pressure on system performance; and (4) monitoring and control strategies.

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

Wireless Capacitive Pressure Sensor Operating up to 400 Celcius from 0 to 100 psi Utilizing Power Scavenging

NASA Technical Reports Server (NTRS)

Scardelletti, Maximilian C.; Ponchak, George E.; Harsh, Kevin; Mackey, Jonathan A.; Meredith, Roger D.; Zorman, Christian A.; Beheim, Glenn M.; Dynys, Frederick W.; Hunter, Gary W.

2014-01-01

In this paper, a wireless capacitive pressure sensor developed for the health monitoring of aircraft engines has been demonstrated. The sensing system is composed of a Clapp-type oscillator that operates at 131 MHz. The Clapp oscillator is fabricated on a alumina substrate and consists of a Cree SiC (silicon carbide) MESFET (Metal Semiconductor Field Effect Transistors), this film inductor, Compex chip capacitors and Sporian Microsystem capacitive pressure sensor. The resonant tank circuit within the oscillator is made up of the pressure sensor and a spiral thin film inductor, which is used to magnetically couple the wireless pressure sensor signal to a coil antenna placed over 1 meter away. 75% of the power used to bias the sensing system is generated from thermoelectric power modules. The wireless pressure sensor is operational at room temperature through 400 C from 0 to 100 psi and exhibits a frequency shift of over 600 kHz.

49 CFR 232.205 - Class I brake test-initial terminal inspection.

Code of Federal Regulations, 2012 CFR

2012-10-01

... test shall be conducted as follows: (A) Charge the air brake system to the pressure at which the train... equivalent pressure maintaining locomotive brake valve, a railroad may use the Air Flow Method Test as an...) Charge the air brake system to the pressure at which the train will be operated, and the pressure at the...

49 CFR 232.205 - Class I brake test-initial terminal inspection.

Code of Federal Regulations, 2014 CFR

2014-10-01

... test shall be conducted as follows: (A) Charge the air brake system to the pressure at which the train... equivalent pressure maintaining locomotive brake valve, a railroad may use the Air Flow Method Test as an...) Charge the air brake system to the pressure at which the train will be operated, and the pressure at the...

49 CFR 232.205 - Class I brake test-initial terminal inspection.

Code of Federal Regulations, 2011 CFR

2011-10-01

... test shall be conducted as follows: (A) Charge the air brake system to the pressure at which the train... equivalent pressure maintaining locomotive brake valve, a railroad may use the Air Flow Method Test as an...) Charge the air brake system to the pressure at which the train will be operated, and the pressure at the...

49 CFR 232.205 - Class I brake test-initial terminal inspection.

Code of Federal Regulations, 2013 CFR

2013-10-01

... test shall be conducted as follows: (A) Charge the air brake system to the pressure at which the train... equivalent pressure maintaining locomotive brake valve, a railroad may use the Air Flow Method Test as an...) Charge the air brake system to the pressure at which the train will be operated, and the pressure at the...

49 CFR 173.5b - Portable and mobile refrigeration systems.

Code of Federal Regulations, 2011 CFR

2011-10-01

... operations. These refrigeration systems are used at field sites to cool (pre-cool) produce before the produce... pressure vessel must be designed, manufactured, and maintained in accordance with applicable requirements... initial pressure test performed after manufacture. Additional pressure tests must be performed after any...

49 CFR 173.5b - Portable and mobile refrigeration systems.

Code of Federal Regulations, 2014 CFR

2014-10-01

... operations. These refrigeration systems are used at field sites to cool (pre-cool) produce before the produce... pressure vessel must be designed, manufactured, and maintained in accordance with applicable requirements... initial pressure test performed after manufacture. Additional pressure tests must be performed after any...

Impact reactivity of materials at very high oxygen pressure

NASA Technical Reports Server (NTRS)

Connor, H. W.; Minchey, J. G.; Crowder, R.; Davidson, R.

1983-01-01

The requirements for impact testing of materials in an oxygen atmosphere at pressures from 82.7 MPa (12,000 psi) to 172 MPa (25,000 psi) were evaluated. The impact tester system was evaluated for potential pressure increases from 69 MPa (10,000 psi) to 82.7 MPa (12,000 psi). The low pressure oxygen and nitrogen systems, the impact tower, the impact test cell, and the high pressure oxygen system were evaluated individually. Although the structural integrity of the impact test cell and the compressor were sufficient for operation at 82.7 MPa (12,000 psi), studies revealed possible material incompatibility at that pressure and above. It was recommended that if a component should be replaced for 82.7 MPa (12,000 psi) operation the replacement should meet the final objectives of 172 MPa (25,000 psi). Recommended changes in the system include; use of Monel 400 for pressures above 82.7 MPa (12,000 psi), use of bellows to replace the seal in the impact tester, use of a sapphire window attached to a fiber optic for event sensing, and use of a three diaphragm compressor.

Reciprocating Feed System Development Status

NASA Technical Reports Server (NTRS)

Trewek, Mary (Technical Monitor); Blackmon, James B.; Eddleman, David E.

2005-01-01

The reciprocating feed system (RFS) is an alternative means of providing high pressure propellant flow at low cost and system mass, with high fail-operational reliability. The RFS functions by storing the liquid propellants in large, low-pressure tanks and then expelling each propellant through two or three small, high-pressure tanks. Each RFS tank is sequentially filled, pressurized, expelled, vented, and refilled so as to provide a constant, or variable, mass flow rate to the engine. This type of system is much lighter than a conventional pressure fed system in part due to the greatly reduced amount of inert tank weight. The delivered payload for an RFS is superior to that of conventional pressure fed systems for conditions of high total impulse and it is competitive with turbopump systems, up to approximately 2000 psi. An advanced version of the RFS uses autogenous pressurization and thrust augmentation to achieve higher performance. In this version, the pressurization gases are combusted in a small engine, thus making the pressurization system, in effect, part of the propulsion system. The RFS appears to be much less expensive than a turbopump system, due to reduced research and development cost and hardware cost, since it is basically composed of small high- pressure tanks, a pressurization system, and control valves. A major benefit is the high reliability fail-operational mode; in the event of a failure in one of the three tank-systems, it can operate on the two remaining tanks. Other benefits include variable pressure and flow rates, ease of engine restart in micro-gravity, and enhanced propellant acquisition and control under adverse acceleration conditions. We present a system mass analysis tool that accepts user inputs for various design and mission parameters and calculates such output values payload and vehicle weights for the conventional pressure fed system, the RFS, the Autogenous Pressurization Thrust Augmentation (APTA) RFS, and turbopump systems. Using this tool, a preliminary design of a representative crew exploration vehicle (CEV) has been considered. The design parameters selected for a representative system were modeled after the orbital maneuvering system (OMS) on the Shuttle Orbiter, with an increase of roughly a factor of ten in the delta- V capability and a greater thrust (30,000 lbs, vs. 12,000 lbs). Both storable and cryogenic propellants were considered. Results show that a RFS is a low mass alternative to conventional pressure fed systems, with a substantial increase in payload capability and that it is weight-competitive with turbopump systems at low engine pressure (a few hundred psi); at high engine pressures, the APTA RFS appears to offer the highest payload. We also present the status of the RFS test bed fabrication, assembly, and checkout. This test bed is designed to provide flow rates appropriate for engines in the roughly 10,000 to 30,000 lb thrust range.

Development Specification for the Portable Life Support System (PLSS) Thermal Loop Pump

NASA Technical Reports Server (NTRS)

Anchondo, Ian; Campbell, Colin

2017-01-01

The AEMU Thermal Loop Pump Development Specification establishes the requirements for design, performance, and testing of the Water Pump as part of the Thermal System of the Advanced Portable Life Support System (PLSS). It is envisioned that the Thermal Loop Pump is a positive displacement pump that provides a repeatable volume of flow against a given range of back-pressures provided by the various applications. The intention is to operate the pump at a fixed speed for the given application. The primary system is made up of two identical and redundant pumps of which only one is in operation at given time. The Auxiliary Loop Pump is an identical pump design to the primary pumps but is operated at half the flow rate. Inlet positive pressure to the pumps is provided by the upstream Flexible Supply Assembly (FSA-431 and FSA-531) which are physically located inside the suit volume and pressurized by suit pressure. An integrated relief valve, placed in parallel to the pump's inlet and outlet protects the pump and loop from over-pressurization. An integrated course filter is placed upstream of the pump's inlet to provide filtration and prevent potential debris from damaging the pump.

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.

Performance comparison of supersonic ejectors with different motive gas injection schemes applicable for flowing medium gas laser

NASA Astrophysics Data System (ADS)

Singhal, G.; Subbarao, P. M. V.; Mainuddin; Tyagi, R. K.; Dawar, A. L.

2017-05-01

A class of flowing medium gas lasers with low generator pressures employ supersonic flows with low cavity pressure and are primarily categorized as high throughput systems capable of being scaled up to MW class. These include; Chemical Oxygen Iodine Laser (COIL) and Hydrogen (Deuterium) Fluoride (HF/DF). The practicability of such laser systems for various applications is enhanced by exhausting the effluents directly to ambient atmosphere. Consequently, ejector based pressure recovery forms a potent configuration for open cycle operation. Conventionally these gas laser systems require at least two ejector stages with low pressure stage being more critical, since it directly entrains the laser media, and the ensuing perturbation of cavity flow, if any, may affect laser operation. Hence, the choice of plausible motive gas injection schemes viz., peripheral or central is a fluid dynamic issue of interest, and a parametric experimental performance comparison would be beneficial. Thus, the focus is to experimentally characterize the effect of variation in motive gas supply pressure, entrainment ratio, back pressure conditions, nozzle injection position operated together with a COIL device and discern the reasons for the behavior.

ORION Environmental Control and Life Support Systems Suit Loop and Pressure Control Analysis

NASA Technical Reports Server (NTRS)

Eckhardt, Brad; Conger, Bruce; Stambaugh, Imelda C.

2015-01-01

Under NASA's ORION Multi-Purpose Crew Vehicle (MPCV) Environmental Control and Life Support System (ECLSS) Project at Johnson Space Center's (JSC), the Crew and Thermal Systems Division has developed performance models of the air system using Thermal Desktop/FloCAD. The Thermal Desktop model includes an Air Revitalization System (ARS Loop), a Suit Loop, a Cabin Loop, and Pressure Control System (PCS) for supplying make-up gas (N2 and O2) to the Cabin and Suit Loop. The ARS and PCS are designed to maintain air quality at acceptable O2, CO2 and humidity levels as well as internal pressures in the vehicle Cabin and during suited operations. This effort required development of a suite of Thermal Desktop Orion ECLSS models to address the need for various simulation capabilities regarding ECLSS performance. An initial highly detailed model of the ARS Loop was developed in order to simulate rapid pressure transients (water hammer effects) within the ARS Loop caused by events such as cycling of the Pressurized Swing Adsorption (PSA) Beds and required high temporal resolution (small time steps) in the model during simulation. A second ECLSS model was developed to simulate events which occur over longer periods of time (over 30 minutes) where O2, CO2 and humidity levels, as well as internal pressures needed to be monitored in the cabin and for suited operations. Stand-alone models of the PCS and the Negative Pressure relief Valve (NPRV) were developed to study thermal effects within the PCS during emergency scenarios (Cabin Leak) and cabin pressurization during vehicle re-entry into Earth's atmosphere. Results from the Orion ECLSS models were used during Orion Delta-PDR (July, 2014) to address Key Design Requirements (KDR's) for Suit Loop operations for multiple mission scenarios.

High speed hydraulically-actuated operating system for an electric circuit breaker

DOEpatents

Iman, I.

1983-06-07

This hydraulically-actuated operating system comprises a cylinder, a piston movable therein in an opening direction to open a circuit breaker, and an accumulator for supplying pressurized liquid to a breaker-opening piston-actuating space within the cylinder. A normally-closed valve between the accumulator and the actuating space is openable to allow pressurized liquid from the accumulator to flow through the valve into the actuating space to drive the piston in an opening direction. A dashpotting mechanism operating separately from the hydraulic actuating system is provided, thereby reducing flow restriction interference with breaker opening. 3 figs.

High speed hydraulically-actuated operating system for an electric circuit breaker

DOEpatents

Iman, Imdad

1983-06-07

This hydraulically-actuated operating system comprises a cylinder, a piston movable therein in an opening direction to open a circuit breaker, and an accumulator for supplying pressurized liquid to a breaker-opening piston-actuating space within the cylinder. A normally-closed valve between the accumulator and the actuating space is openable to allow pressurized liquid from the accumulator to flow through the valve into the actuating space to drive the piston in an opening direction. A dashpotting mechanism operating separately from the hydraulic actuating system is provided, thereby reducing flow restriction interference with breaker opening.

A novel APPI-MS setup for in situ degradation product studies of atmospherically relevant compounds: capillary atmospheric pressure photo ionization (cAPPI).

PubMed

Kersten, Hendrik; Derpmann, Valerie; Barnes, Ian; Brockmann, Klaus J; O'Brien, Rob; Benter, Thorsten

2011-11-01

We report on the development of a novel atmospheric pressure photoionization setup and its applicability for in situ degradation product studies of atmospherically relevant compounds. A custom miniature spark discharge lamp was embedded into an ion transfer capillary, which separates the atmospheric pressure from the low pressure region in the first differential pumping stage of a conventional atmospheric pressure ionization mass spectrometer. The lamp operates with a continuous argon flow and produces intense light emissions in the VUV. The custom lamp is operated windowless and efficiently illuminates the sample flow through the transfer capillary on an area smaller than 1 mm(2). Limits of detection in the lower ppbV range, a temporal resolution of milliseconds in the positive as well as the quasi simultaneously operating negative ion mode, and a significant reduction of ion transformation processes render this system applicable to real time studies of rapidly changing chemical systems. The method termed capillary atmospheric pressure photo ionization (cAPPI) is characterized with respect to the lamp emission properties as a function of the operating conditions, temporal response, and its applicability for in situ degradation product studies of atmospherically relevant compounds, respectively.

Transient Behavior of Lumped-Constant Systems for Sensing Gas Pressures

NASA Technical Reports Server (NTRS)

Delio, Gene J; Schwent, Glennon V; Cesaro, Richard S

1949-01-01

The development of theoretical equations describing the behavior of a lumped-constant pressure-sensing system under transient operation Is presented with experimental data that show agreement with the equations. A pressure-sensing system 'consisting of a tube terminating in a reservoir is investigated for the transient relation between a presSure disturbance at the open end of the tube and the pressure response in the reservoir. Design parameters are presented that can be adjusted to achieve a desired performance fran such a system when the system is considered as a transfer member of a control loop.

Physics Simulation Software for Autonomous Propellant Loading and Gas House Autonomous System Monitoring

NASA Technical Reports Server (NTRS)

Regalado Reyes, Bjorn Constant

2015-01-01

1. Kennedy Space Center (KSC) is developing a mobile launching system with autonomous propellant loading capabilities for liquid-fueled rockets. An autonomous system will be responsible for monitoring and controlling the storage, loading and transferring of cryogenic propellants. The Physics Simulation Software will reproduce the sensor data seen during the delivery of cryogenic fluids including valve positions, pressures, temperatures and flow rates. The simulator will provide insight into the functionality of the propellant systems and demonstrate the effects of potential faults. This will provide verification of the communications protocols and the autonomous system control. 2. The High Pressure Gas Facility (HPGF) stores and distributes hydrogen, nitrogen, helium and high pressure air. The hydrogen and nitrogen are stored in cryogenic liquid state. The cryogenic fluids pose several hazards to operators and the storage and transfer equipment. Constant monitoring of pressures, temperatures and flow rates are required in order to maintain the safety of personnel and equipment during the handling and storage of these commodities. The Gas House Autonomous System Monitoring software will be responsible for constantly observing and recording sensor data, identifying and predicting faults and relaying hazard and operational information to the operators.

Activation of the E1 Ultra High Pressure Propulsion Test Facility at Stennis Space Center

NASA Technical Reports Server (NTRS)

Messer, Bradley; Messer, Elisabeth; Sewell, Dale; Sass, Jared; Lott, Jeff; Dutreix, Lionel, III

2001-01-01

After a decade of construction and a year of activation the El Ultra High Pressure Propulsion Test Facility at NASA's Stennis Space Center is fully operational. The El UHP Propulsion Test Facility is a multi-cell, multi-purpose component and engine test facility . The facility is capable of delivering cryogenic propellants at low, high, and ultra high pressures with flow rates ranging from a few pounds per second up to two thousand pounds per second. Facility activation is defined as a series of tasks required to transition between completion of construction and facility operational readiness. Activating the El UHP Propulsion Test Facility involved independent system checkouts, propellant system leak checks, fluid and gas sampling, gaseous system blow downs, pressurization and vent system checkouts, valve stability testing, valve tuning cryogenic cold flows, and functional readiness tests.

46 CFR 151.40-10 - Operational requirements.

Code of Federal Regulations, 2010 CFR

2010-10-01

... shall operate when either the pressure or the temperature exceeds the operating limits of the system... Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CERTAIN BULK DANGEROUS CARGOES BARGES... Operational requirements. Control systems, required by Table 151.05 shall be provided with an audible or...

40 CFR 63.3556 - How do I establish the emission capture system and add-on control device operating limits during...

Code of Federal Regulations, 2010 CFR

2010-07-01

... system and add-on control device operating limits during the performance test? 63.3556 Section 63.3556... of key parameters of the valve operating system (e.g., solenoid valve operation, air pressure.../outlet Concentration Option § 63.3556 How do I establish the emission capture system and add-on control...

40 CFR 63.3556 - How do I establish the emission capture system and add-on control device operating limits during...

Code of Federal Regulations, 2011 CFR

2011-07-01

... system and add-on control device operating limits during the performance test? 63.3556 Section 63.3556... of key parameters of the valve operating system (e.g., solenoid valve operation, air pressure.../outlet Concentration Option § 63.3556 How do I establish the emission capture system and add-on control...

40 CFR 63.3556 - How do I establish the emission capture system and add-on control device operating limits during...

Code of Federal Regulations, 2013 CFR

2013-07-01

... system and add-on control device operating limits during the performance test? 63.3556 Section 63.3556... of key parameters of the valve operating system (e.g., solenoid valve operation, air pressure... Control Efficiency/outlet Concentration Option § 63.3556 How do I establish the emission capture system...

Reactor water cleanup system

DOEpatents

Gluntz, D.M.; Taft, W.E.

1994-12-20

A reactor water cleanup system includes a reactor pressure vessel containing a reactor core submerged in reactor water. First and second parallel cleanup trains are provided for extracting portions of the reactor water from the pressure vessel, cleaning the extracted water, and returning the cleaned water to the pressure vessel. Each of the cleanup trains includes a heat exchanger for cooling the reactor water, and a cleaner for cleaning the cooled reactor water. A return line is disposed between the cleaner and the pressure vessel for channeling the cleaned water thereto in a first mode of operation. A portion of the cooled water is bypassed around the cleaner during a second mode of operation and returned through the pressure vessel for shutdown cooling. 1 figure.

Membrane Separation Processes at Low Temperatures

NASA Technical Reports Server (NTRS)

Parrish, Clyde

2002-01-01

The primary focus of Kennedy Space Center's gas separation activities has been for carbon dioxide, nitrogen, and argon used in oxygen production technologies for Martian in-situ resource utilization (ISRU) projects. Recently, these studies were expanded to include oxygen for regenerative life support systems. Since commercial membrane systems have been developed for separation of carbon dioxide, nitrogen, and oxygen, initially the studies focused on these membrane systems, but at lower operating temperatures and pressures. Current investigations art examining immobilized liquids and solid sorbents that have the potential for higher selectivity and lower operating temperatures. The gas separation studies reported here use hollow fiber membranes to separate carbon dioxide, nitrogen, and argon in the temperature range from 230 to 300 K. Four commercial membrane materials were used to obtain data at low feed and permeate pressures. These data were used with a commercial solution-diffusion modeling tool to design a system to prepare a buffer gas from the byproduct of a process to capture Martian carbon dioxide. The system was designed to operate, at 230 K with a production rate 0.1 sLpm; Feed composition 30% CO2, 44% N2, and 26% Ar; Feed pressure 104 kPa (780); and Permeate pressure 1 kPa (6 torr); Product concentration 600 ppm CO2. This new system was compared with a similar system designed to operate at ambient temperatures (298 K). The systems described above, along with data, test apparatus, and models are presented.

Analytical Assessment of the Reciprocating Feed System

NASA Technical Reports Server (NTRS)

Eddleman, David E.; Blackmon, James B.; Morton, Christopher D.

2006-01-01

A preliminary analysis tool has been created in Microsoft Excel to determine deliverable payload mass, total system mass, and performance of spacecraft systems using various types of propellant feed systems. These mass estimates are conducted by inserting into the user interface the basic mission parameters (e.g., thrust, burn time, specific impulse, mixture ratio, etc.), system architecture (e.g., propulsion system type and characteristics, propellants, pressurization system type, etc.), and design properties (e.g., material properties, safety factors, etc.). Different propellant feed and pressurization systems are available for comparison in the program. This gives the user the ability to compare conventional pressure fed, reciprocating feed system (RFS), autogenous pressurization thrust augmentation (APTA RFS), and turbopump systems with the deliverable payload, inert mass, and total system mass being the primary comparison metrics. Analyses of several types of missions and spacecraft were conducted and it was found that the RFS offers a performance improvement, especially in terms of delivered payload, over conventional pressure fed systems. Furthermore, it is competitive with a turbopump system at low to moderate chamber pressures, up to approximately 1,500 psi. Various example cases estimating the system mass and deliverable payload of several types of spacecraft are presented that illustrate the potential system performance advantages of the RFS. In addition, a reliability assessment of the RFS was conducted, comparing it to simplified conventional pressure fed and turbopump systems, based on MIL-STD 756B; these results showed that the RFS offers higher reliability, and thus substantially longer periods between system refurbishment, than turbopump systems, and is competitive with conventional pressure fed systems. This is primarily the result of the intrinsic RFS fail-operational capability with three run tanks, since the system can operate with just two run tanks.

System Would Regulate Low Gas Pressure

NASA Technical Reports Server (NTRS)

Frazer, Robert E.

1994-01-01

System intended to maintain gases in containers at pressures near atmospheric. Includes ballast volume in form of underinflated balloon that communicates with working volume. Balloon housed in rigid chamber not subjected to extremes of temperature of working volume. Pressure in chamber surrounding balloon regulated at ambient atmospheric pressure or at constant small differential pressure above or below ambient. Expansion and contraction of balloon accommodates expansion or contraction of gas during operational heating or cooling in working volume, maintaining pressure in working volume at ambient or constant differential above or below ambient. Gas lost from system due to leakage or diffusion, low-pressure sensor responds, signaling valve actuators to supply more gas to working volume. If pressure rises too high, overpressure relief valve opens before excessive pressure damages system.

High-pressure plastic scintillation detector for measuring radiogenic gases in flow systems

NASA Astrophysics Data System (ADS)

Schell, W. R.; Vives-Batlle, J.; Yoon, S. R.; Tobin, M. J.

1999-02-01

Radioactive gases are emitted into the atmosphere from nuclear electric power and nuclear fuel reprocessing plants, from hospitals discarding xenon used in diagnostic medicine, as well as from nuclear weapons tests. A high-pressure plastic scintillation detector was constructed to measure atmospheric levels of such radioactive gases by detecting the beta and internal conversion (IC) electron decays. Operational tests and calibrations were made that permit integration of the flow detectors into a portable Gas Analysis, Separation and Purification system (GASP). The equipment developed can be used for measuring fission gases released from nuclear reactor sources and/or as part of monitoring equipment for enforcing the Comprehensive Test Ban Treaty. The detector is being used routinely for in-line gas separation efficiency measurements, at the elevated operational pressures used for the high-pressure swing analysis system (2070 kPa) and at flow rates of 5-15 l/min [1, 2]. This paper presents the design features, operational methods, calibration, and detector applications.

Liquid Bismuth Propellant Management System for the Very High Specific Impulse Thruster with Anode Layer

NASA Technical Reports Server (NTRS)

Polzin, K. A.; Markusic, T. E.; Stanojev, B. J.

2007-01-01

Two prototype bismuth propellant feed systems were constructed and operated in conjunction with a propellant vaporizer. One system provided bismuth to a vaporizer using gas pressurization but did not include a means to measure the flow rate. The second system incorporated an electromagnetic pump to provide fine control of the hydrostatic pressure and a new type of in-line flow sensor that was developed for accurate, real-time measurement of the mass flow rate. High-temperature material compatibility was a driving design requirement for the pump and flow sensor, leading to the selection of Macor for the main body of both components. Posttest inspections of both components revealed no degradation of the material. The gas pressurization system demonstrated continuous pressure control over a range from zero to 200 torr. In separate proof-of-concept experiments, the electromagnetic pump produced a linear pressure rise as a function of current that compared favorably with theoretical pump pressure predictions, producing a pressure rise of 10 kPa at 30 A. Preliminary flow sensor operation indicated a bismuth flow rate of 6 mg/s with an uncertainty of plus or minus 6%. An electronics suite containing a real-time controller was successfully used to control the entire system, simultaneously monitoring all power supplies and performing data acquisition duties.

Containment vessel drain system

DOEpatents

Harris, Scott G.

2018-01-30

A system for draining a containment vessel may include a drain inlet located in a lower portion of the containment vessel. The containment vessel may be at least partially filled with a liquid, and the drain inlet may be located below a surface of the liquid. The system may further comprise an inlet located in an upper portion of the containment vessel. The inlet may be configured to insert pressurized gas into the containment vessel to form a pressurized region above the surface of the liquid, and the pressurized region may operate to apply a surface pressure that forces the liquid into the drain inlet. Additionally, a fluid separation device may be operatively connected to the drain inlet. The fluid separation device may be configured to separate the liquid from the pressurized gas that enters the drain inlet after the surface of the liquid falls below the drain inlet.

33 CFR 150.15 - What must the operations manual include?

Code of Federal Regulations, 2014 CFR

2014-07-01

... structure and systems. The operator must include schematics of all applicable systems. Schematics must show the location of valves, gauges, system working pressure, relief settings, monitoring systems, and other pertinent information. (d) Communications system. A description of a comprehensive communications...

33 CFR 150.15 - What must the operations manual include?

Code of Federal Regulations, 2013 CFR

2013-07-01

... structure and systems. The operator must include schematics of all applicable systems. Schematics must show the location of valves, gauges, system working pressure, relief settings, monitoring systems, and other pertinent information. (d) Communications system. A description of a comprehensive communications...

[Oxygen-transporting function of the blood circulation system in sevoflurane anesthesia during myocardial revascularization under extracorporeal circulation].

PubMed

Skopets, A A; Lomivorotov, V V; Karakhalis, N B; Makarov, A A; Duman'ian, E S; Lomivorotova, L V

2009-01-01

The purpose of the study was to evaluate the efficiency of oxygen-transporting function of the circulatory system under sevoflurane anesthesia during myocardial revascularization operations under extracorporeal circulation. Twenty-five patients with coronary heart disease were examined. Mean blood pressure, heart rate, cardiac index, total peripheral vascular resistance index, pulmonary pressure, pulmonary wedge pressure, and central venous pressure were measured. Arterial and mixed venous blood oxygen levels, oxygen delivery and consumption index, arteriovenous oxygen difference, and glucose and lactate concentrations were calculated. The study has demonstrated that sevoflurane is an effective and safe anesthetic for myocardial revascularization operations in patients with coronary heart disease. The use of sevoflurane contributes to steady-state oxygen-transporting function of the circulatory system at all surgical stages.

Pressure and Temperature Sensitive Paint Field System

NASA Technical Reports Server (NTRS)

Sprinkle, Danny R.; Obara, Clifford J.; Amer, Tahani R.; Faulcon, Nettie D.; Carmine, Michael T.; Burkett, Cecil G.; Pritchard, Daniel W.; Oglesby, Donald M.

2004-01-01

This report documents the Pressure and Temperature Sensitive Paint Field System that is used to provide global surface pressure and temperature measurements on models tested in Langley wind tunnels. The system was developed and is maintained by Global Surface Measurements Team personnel of the Data Acquisition and Information Management Branch in the Research Facilities Services Competency. Descriptions of the system hardware and software are presented and operational procedures are detailed.

Optimizing the physical ergonomics indices for the use of partial pressure suits.

PubMed

Ding, Li; Li, Xianxue; Hedge, Alan; Hu, Huimin; Feathers, David; Qin, Zhifeng; Xiao, Huajun; Xue, Lihao; Zhou, Qianxiang

2015-03-01

This study developed an ergonomic evaluation system for the design of high-altitude partial pressure suits (PPSs). A total of twenty-one Chinese males participated in the experiment which tested three types of ergonomics indices (manipulative mission, operational reach and operational strength) were studied using a three-dimensional video-based motion capture system, a target-pointing board, a hand dynamometer, and a step-tread apparatus. In total, 36 ergonomics indices were evaluated and optimized using regression and fitting analysis. Some indices that were found to be linearly related and redundant were removed from the study. An optimal ergonomics index system was established that can be used to conveniently and quickly evaluate the performance of different pressurized/non-pressurized suit designs. The resulting ergonomics index system will provide a theoretical basis and practical guidance for mission planners, suit designers and engineers to design equipment for human use, and to aid in assessing partial pressure suits. Copyright © 2014 Elsevier Ltd and The Ergonomics Society. All rights reserved.

14 CFR 23.1435 - Hydraulic systems.

Code of Federal Regulations, 2012 CFR

2012-01-01

... addition to hydraulic loads. (2) A means to indicate the pressure in each hydraulic system which supplies... maximum operating pressure of that system. (c) Accumulators. A hydraulic accumulator or reservoir may be... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Hydraulic systems. 23.1435 Section 23.1435...

14 CFR 23.1435 - Hydraulic systems.

Code of Federal Regulations, 2010 CFR

2010-01-01

... addition to hydraulic loads. (2) A means to indicate the pressure in each hydraulic system which supplies... maximum operating pressure of that system. (c) Accumulators. A hydraulic accumulator or reservoir may be... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Hydraulic systems. 23.1435 Section 23.1435...

14 CFR 23.1435 - Hydraulic systems.

Code of Federal Regulations, 2011 CFR

2011-01-01

... addition to hydraulic loads. (2) A means to indicate the pressure in each hydraulic system which supplies... maximum operating pressure of that system. (c) Accumulators. A hydraulic accumulator or reservoir may be... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Hydraulic systems. 23.1435 Section 23.1435...

14 CFR 23.1435 - Hydraulic systems.

Code of Federal Regulations, 2013 CFR

2013-01-01

... addition to hydraulic loads. (2) A means to indicate the pressure in each hydraulic system which supplies... maximum operating pressure of that system. (c) Accumulators. A hydraulic accumulator or reservoir may be... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Hydraulic systems. 23.1435 Section 23.1435...

14 CFR 23.1435 - Hydraulic systems.

Code of Federal Regulations, 2014 CFR

2014-01-01

... addition to hydraulic loads. (2) A means to indicate the pressure in each hydraulic system which supplies... maximum operating pressure of that system. (c) Accumulators. A hydraulic accumulator or reservoir may be... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Hydraulic systems. 23.1435 Section 23.1435...

Low-temperature overpressurization protection system setpoint analysis using RETRAN-02/MOD5 for Salem

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

Dodson, R.J.; Feltus, M.A.

The low-temperature overpressurization protection system (LTOPS) is designed to protect the reactor pressure vessel (RPV) from brittle failure during startup and cooldown maneuvers in Westinghouse pressurized water reactors. For the Salem power plants, the power-operated relief valves (PORVs) mitigate pressure increases above a setpoint where an operational startup transient may put the RPV in the embrittlement fracture zone. The Title 10, Part 50, Code of Federal Regulations Appendix G limit, given by plant technical specifications, conservatively bounds the maximum pressure allowed during those transients where the RPV can suffer brittle fracture (usually below 350{degrees}F). The Appendix G limit is amore » pressure versus temperature curve that is more restrictive at lower RPV temperatures and allows for higher pressures as the temperature approaches the upper bounding fracture temperature.« less

30 CFR 250.616 - Blowout preventer system testing, records, and drills.

Code of Federal Regulations, 2011 CFR

2011-07-01

... drills. 250.616 Section 250.616 Mineral Resources BUREAU OF OCEAN ENERGY MANAGEMENT, REGULATION, AND... drills. (a) BOP pressure tests. When you pressure test the BOP system you must conduct a low-pressure... engaged in well-workover operations shall participate in a weekly BOP drill to familiarize crew members...

40 CFR 60.274a - Monitoring of operations.

Code of Federal Regulations, 2010 CFR

2010-07-01

... the equipment that is important to the performance of the total capture system (i.e., pressure sensors... this subpart shall check and record on a once-per-shift basis the furnace static pressure (if DEC system is in use, and a furnace static pressure gauge is installed according to paragraph (f) of this...

Battery management systems with thermally integrated fire suppression

DOEpatents

Bandhauer, Todd M.; Farmer, Joseph C.

2017-07-11

A thermal management system is integral to a battery pack and/or individual cells. It relies on passive liquid-vapor phase change heat removal to provide enhanced thermal protection via rapid expulsion of inert high pressure refrigerant during abnormal abuse events and can be integrated with a cooling system that operates during normal operation. When a thermal runaway event occurs and sensed by either active or passive sensors, the high pressure refrigerant is preferentially ejected through strategically placed passages within the pack to rapidly quench the battery.

Orbital maneuvering subsystem functional path analysis for performance monitoring fault detection and annunciation

NASA Technical Reports Server (NTRS)

Keesler, E. L.

1974-01-01

The functional paths of the Orbital Maneuver Subsystem (OMS) is defined. The operational flight instrumentation required for performance monitoring, fault detection, and annunciation is described. The OMS is a pressure fed rocket engine propulsion subsystem. One complete OMS shares each of the two auxiliary propulsion subsystem pods with a reaction control subsystem. Each OMS is composed of a pressurization system, a propellant tanking system, and a gimbaled rocket engine. The design, development, and operation of the system are explained. Diagrams of the system are provided.

Influence evaluation of loading conditions during pressurized thermal shock transients based on thermal-hydraulics and structural analyses

NASA Astrophysics Data System (ADS)

Katsuyama, Jinya; Uno, Shumpei; Watanabe, Tadashi; Li, Yinsheng

2018-03-01

The thermal hydraulic (TH) behavior of coolant water is a key factor in the structural integrity assessments on reactor pressure vessels (RPVs) of pressurized water reactors (PWRs) under pressurized thermal shock (PTS) events, because the TH behavior may affect the loading conditions in the assessment. From the viewpoint of TH behavior, configuration of plant equipment and their dimensions, and operator action time considerably influence various parameters, such as the temperature and flow rate of coolant water and inner pressure. In this study, to investigate the influence of the operator action time on TH behavior during a PTS event, we developed an analysis model for a typical Japanese PWR plant, including the RPV and the main components of both primary and secondary systems, and performed TH analyses by using a system analysis code called RELAP5. We applied two different operator action times based on the Japanese and the United States (US) rules: Operators may act after 10 min (Japanese rules) and 30 min (the US rules) after the occurrence of PTS events. Based on the results of TH analysis with different operator action times, we also performed structural analyses for evaluating thermal-stress distributions in the RPV during PTS events as loading conditions in the structural integrity assessment. From the analysis results, it was clarified that differences in operator action times significantly affect TH behavior and loading conditions, as the Japanese rule may lead to lower stresses than that under the US rule because an earlier operator action caused lower pressure in the RPV.

Solid polymer electrolyte water electrolysis system development. [to generate oxygen for manned space station applications

NASA Technical Reports Server (NTRS)

1975-01-01

Solid polymer electrolyte technology used in a water electrolysis system (WES) to generate oxygen and hydrogen for manned space station applications was investigated. A four-man rated, low pressure breadboard water electrolysis system with the necessary instrumentation and controls was fabricated and tested. A six man rated, high pressure, high temperature, advanced preprototype WES was developed. This configuration included the design and development of an advanced water electrolysis module, capable of operation at 400 psig and 200 F, and a dynamic phase separator/pump in place of a passive phase separator design. Evaluation of this system demonstrated the goal of safe, unattended automated operation at high pressure and high temperature with an accumulated gas generation time of over 1000 hours.

Fatigue life analysis of cracked gas receiver of emergency cut-off system in gas gathering station

NASA Astrophysics Data System (ADS)

Hu, Junzhi; Zhou, Jiyong; Li, Siyuan

2017-06-01

Small-scale air compressor and gas receiver are used as the driving gas of the emergency cut-off system in gas gathering station. Operation of block valve is ensured by starting and stopping compressor automatically. The frequent start-stop of compressor and the pressure fluctuation pose a threat to the service life of gas receiver, and then affect normal operation of the emergency cut-off system and security of gas gathering station. In this paper, the fatigue life of a pressure vessel with axial semi-elliptical surface crack in the inner wall is analyzed under the varying pressure by means of the theory of fracture mechanics. The influences of the amplitude of pressure fluctuation and the initial crack size on the residual life of gas receiver are discussed. It provides a basis for setting the working parameters of gas receiver of emergency cut-off system and determining the maintenance cycle.

High-pressure cryogenic seals for pressure vessels

NASA Technical Reports Server (NTRS)

Buggele, A. E.

1977-01-01

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

Development, modeling, simulation, and testing of a novel propane-fueled Brayton-Gluhareff cycle acoustically-pressurized ramjet engine

NASA Astrophysics Data System (ADS)

Bramlette, Richard B.

In the 1950s, Eugene Gluhareff built the first working "pressure jet" engine, a variation on the classical ramjet engine with a pressurized inlet system relying on sonic tuning which allowed operation at subsonic speeds. The engine was an unqualified success. Unfortunately, after decades of sales and research, Gluhareff passed away leaving behind no significant published studies of the engine or detailed analysis of its operation. The design was at serious risk of being lost to history. This dissertation is intended to address that risk by studying a novel subscale modification of Gluhareff's original design operating on the same principles. Included is a background of related engine and how the pressure jet is distinct. The preliminary sizing of a pressure jet using closed-form expressions is then discussed followed by a review of propane oxidation modeling, how it integrates into the Computational Fluid Dynamics (CFD) solver, and the modeling of the pressure jet engine cycle with CFD. The simulation was matched to experimental data recorded on a purpose-built test stand recording chamber pressure, exhaust speed (via a Pitot/static system), temperatures, and thrust force. The engine CFD simulation produced a wide range of qualitative results that matched the experimental data well and suggested strong recirculation flows through the engine confirming suspicions about how the engine operates. Engine operating frequency between CFD and experiment also showed good agreement and appeared to be driven by the "Kadenacy Effect." The research effort lastly opens the door for further study of the engine cycle, the use of pressurized intakes to produce static thrust in a ramjet engine, the Gluhareff pressure jet's original geometry, and a wide array of potential applications. A roadmap of further study and applications is detailed including a modeling and testing of larger engines.

Design, fabrication, assembly, and test of a liquid hydrogen acquisition subsystem

NASA Technical Reports Server (NTRS)

Blackman, J. B.

1974-01-01

The development of a cryogenic fluid system to supply liquid hydrogen to a turbopump at flowrates up to 7.5 pounds per second for a period of approximately 5 seconds before refill, is discussed. Refill is accomplished in less than 10 seconds, during which a constant flowrate can be maintained to the pumps. Diagrams are provided to show the configuration of the system. Subsystem acceptance and functional tests, including acquisition subsystem expulsion, pressurization, and refill were performed. The tests included: (1) thermodynamic vent system operation, (2) warm-gas pressurization effects, (3) hydraulic pressure surge effects, (4) screen device operational limitations, (5) feedline vapor control, and (6) two-phase refill.

Experimental and Computational Study of the Hydrodynamics of Trickle Bed Flow Reactor Operating Under Different Pressure Conditions

NASA Astrophysics Data System (ADS)

Rabbani, S.; Ben Salem, I.; Nadeem, H.; Kurnia, J. C.; Shamim, T.; Sassi, M.

2014-12-01

Pressure drop estimation and prediction of liquid holdup play a crucial role in design and operation of trickle bed reactors. Experiments are performed for Light Gas Oil (LGO)-nitrogen system in ambient temperature conditions in an industrial pilot plant with reactor height 0.79 m and diameter of 0.0183 m and pressure ranging from atmospheric to 10 bars. It was found that pressure drop increased with increase in system pressure, superficial gas velocity and superficial liquid velocity. It was demonstrated in the experiments that liquid holdup of the system increases with the increase in superficial liquid velocity and tends to decrease with increase in superficial gas velocity which is in good agreement with existing literature. Similar conditions were also simulated using CFD-software FLUENT. The Volume of Fluid (VoF) technique was employed in combination with "discrete particle approach" and results were compared with that of experiments. The overall pressure drop results were compared with the different available models and a new comprehensive model was proposed to predict the pressure drop in Trickle Bed Flow Reactor.

Systems and methods of monitoring acoustic pressure to detect a flame condition in a gas turbine

DOEpatents

Ziminsky, Willy Steve [Simpsonville, SC; Krull, Anthony Wayne [Anderson, SC; Healy, Timothy Andrew , Yilmaz, Ertan

2011-05-17

A method may detect a flashback condition in a fuel nozzle of a combustor. The method may include obtaining a current acoustic pressure signal from the combustor, analyzing the current acoustic pressure signal to determine current operating frequency information for the combustor, and indicating that the flashback condition exists based at least in part on the current operating frequency information.

40 CFR 63.9916 - What test methods and other procedures must I use to establish and demonstrate initial compliance...

Code of Federal Regulations, 2011 CFR

2011-07-01

... compliance with the operating limits? For a wet scrubber subject to operating limits for pressure drop and scrubber water flow rate in § 63.9890(b), you must establish site-specific operating limits according to... monitoring system (CPMS) required in § 63.9920, measure and record the pressure drop and scrubber water flow...

40 CFR 63.9916 - What test methods and other procedures must I use to establish and demonstrate initial compliance...

Code of Federal Regulations, 2010 CFR

2010-07-01

... compliance with the operating limits? For a wet scrubber subject to operating limits for pressure drop and scrubber water flow rate in § 63.9890(b), you must establish site-specific operating limits according to... monitoring system (CPMS) required in § 63.9920, measure and record the pressure drop and scrubber water flow...

40 CFR 63.9916 - What test methods and other procedures must I use to establish and demonstrate initial compliance...

Code of Federal Regulations, 2012 CFR

2012-07-01

... compliance with the operating limits? For a wet scrubber subject to operating limits for pressure drop and scrubber water flow rate in § 63.9890(b), you must establish site-specific operating limits according to... monitoring system (CPMS) required in § 63.9920, measure and record the pressure drop and scrubber water flow...

40 CFR 63.9916 - What test methods and other procedures must I use to establish and demonstrate initial compliance...

Code of Federal Regulations, 2013 CFR

2013-07-01

... compliance with the operating limits? For a wet scrubber subject to operating limits for pressure drop and scrubber water flow rate in § 63.9890(b), you must establish site-specific operating limits according to... monitoring system (CPMS) required in § 63.9920, measure and record the pressure drop and scrubber water flow...

40 CFR 63.9916 - What test methods and other procedures must I use to establish and demonstrate initial compliance...

Code of Federal Regulations, 2014 CFR

2014-07-01

... compliance with the operating limits? For a wet scrubber subject to operating limits for pressure drop and scrubber water flow rate in § 63.9890(b), you must establish site-specific operating limits according to... monitoring system (CPMS) required in § 63.9920, measure and record the pressure drop and scrubber water flow...

Spontaneous Raman Scattering (SRS) System for Calibrating High-Pressure Flames Became Operational

NASA Technical Reports Server (NTRS)

Nguyen, Quang-Viet

2003-01-01

A high-performance spontaneous Raman scattering (SRS) system for measuring quantitative species concentration and temperature in high-pressure flames is now operational. The system is located in Glenn s Engine Research Building. Raman scattering is perhaps the only optical diagnostic technique that permits the simultaneous (single-shot) measurement of all major species (N2, O2, CO2, H2O, CO, H2, and CH4) as well as temperature in combustion systems. The preliminary data acquired with this new system in a 20-atm hydrogen-air (H2-air) flame show excellent spectral coverage, good resolution, and a signal-to-noise ratio high enough for the data to serve as a calibration standard. This new SRS diagnostic system is used in conjunction with the newly developed High- Pressure Gaseous Burner facility (ref. 1). The main purpose of this diagnostic system and the High-Pressure Gaseous Burner facility is to acquire and establish a comprehensive Raman-scattering spectral database calibration standard for the combustion diagnostic community. A secondary purpose of the system is to provide actual measurements in standardized flames to validate computational combustion models. The High-Pressure Gaseous Burner facility and its associated SRS system will provide researchers throughout the world with new insights into flame conditions that simulate the environment inside the ultra-high-pressure-ratio combustion chambers of tomorrow s advanced aircraft engines.

Operational considerations in monitoring oxygen levels at the National Transonic Facility

NASA Technical Reports Server (NTRS)

Zalenski, M. A.; Rowe, E. L.; Mcphee, J. R.

1985-01-01

Laboratory monitoring of the level of oxygen in sample gas mixtures is a process which can be performed with accurate and repeatable results. Operations at the National Transonic Facility require the storage and pumping of large volumes of liquid nitrogen. To protect against the possibility of a fault resulting in a localized oxygen deficient atmosphere, the facility is equipped with a monitoring system with an array of sensors. During the early operational stages, the system produced recurrent alarms, none of which could be traced to a true oxygen deficiency. A thorough analysis of the system was undertaken with primary emphasis placed on the sensor units. These units sense the partial pressure of oxygen which, after signal conditioning, is presented as a % by volume indication at the system output. It was determined that many of the problems experienced were due to a lack of proper accounting for the partial pressure/% by volume relationship, with a secondary cause being premature sensor failure. Procedures were established to consider atmospherically induced partial pressure variations. Sensor rebuilding techniques were examined, and those elements contributing to premature sensor failure were identified. The system now operates with a high degree of confidence and reliability.

Closed-loop helium circulation system for actuation of a continuously operating heart catheter pump.

PubMed

Karabegovic, Alen; Hinteregger, Markus; Janeczek, Christoph; Mohl, Werner; Gföhler, Margit

2017-06-09

Currently available, pneumatic-based medical devices are operated using closed-loop pulsatile or open continuous systems. Medical devices utilizing gases with a low atomic number in a continuous closed loop stream have not been documented to date. This work presents the construction of a portable helium circulation addressing the need for actuating a novel, pneumatically operated catheter pump. The design of its control system puts emphasis on the performance, safety and low running cost of the catheter pump. Static and dynamic characteristics of individual elements in the circulation are analyzed to ensure a proper operation of the system. The pneumatic circulation maximizes the working range of the drive unit inside the catheter pump while reducing the total size and noise production.Separate flow and pressure controllers position the turbine's working point into the stable region of the pressure creation element. A subsystem for rapid gas evacuation significantly decreases the duration of helium removal after a leak, reaching subatmospheric pressure in the intracorporeal catheter within several milliseconds. The system presented in the study offers an easy control of helium mass flow while ensuring stable behavior of its internal components.

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

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

Straub, AP; Yip, NY; Elimelech, M

2014-01-01

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

30 CFR 250.1610 - Blowout preventer systems and system components.

Code of Federal Regulations, 2011 CFR

2011-07-01

... pressure at least as great as the rated working pressure of the ram-type BOP's or as otherwise approved by..., and including, the choke manifold with a pressure rating at least as great as the rated working...-string operations, the BOP stack shall be equipped with conventional and/or variable-bore pipe rams to...

Hydraulically-activated operating system for an electric circuit breaker

DOEpatents

Imam, Imdad; Barkan, Philip

1979-01-01

This operating system comprises a fluid motor having a piston, a breaker-opening space at one side of the piston, and a breaker-closing space at its opposite side. An accumulator freely communicates with the breaker-opening space for supplying pressurized fluid thereto during a circuit-breaker opening operation. A normally-closed valve located on the breaker-closing-side of the piston is openable to release liquid from the breaker-closing space so that pressurized liquid in the breaker-opening space can drive the piston in an opening direction. Means is provided for restoring the valve to its closed position following the circuit-breaker opening operation. An impeded passage affords communication between the accumulator and the breaker-closing space to allow pressurized liquid to flow from the accumulator to the breaker-closing space and develop a pressure therein substantially equal to accumulator pressure when the valve is restored to closed position following breaker-opening. This passage is so impeded that the flow therethrough from the accumulator into the breaker-closing space is sufficiently low during initial opening motion of the piston through a substantial portion of its opening stroke as to avoid interference with said initial opening motion of the piston.

Measurement of intraosseous pressures generated by the Wand, high-pressure periodontal ligament syringe, and the Stabident system.

PubMed

Shepherd, P A; Eleazer, P D; Clark, S J; Scheetz, J P

2001-06-01

Intraosseous pressure generated by the use of three anesthetic systems-the Wand; a hand-operated high-pressure periodontal ligament (PDL) syringe; and the Stabident system-were studied in fresh mandibles of 14 large swine. The mandibles were drilled and tapped in one area of both the right and left posterior molar regions. Pressure gauges were attached via threaded fittings. Pressures during injection were recorded for the Wand first, then the PDL syringe, and finally Stabident. Results showed averages of 8.3 mm Hg generated by the Wand, 16.3 mm Hg with the high-pressure PDL syringe, and 43.7 mm Hg from the Stabident system. Results were corroborated with data from three human cadaver mandibles.

Engineering approach for cost effective operation of industrial pump systems

NASA Astrophysics Data System (ADS)

Krickis, O.; Oleksijs, R.

2017-10-01

Power plants operators are persuaded to operate the main equipment such as centrifugal pumps in economically effective way. The operation of pump sets of district heating network at power plants should be done according to prescriptions of the original equipment manufacturer with further implementation of these requirements to distributed control system of the plant. In order to operate industrial pump sets with a small number of malfunctions is necessary to control the duty point of pump sets in H-Q coordinates, which could be complex task in some installations. Alternatively, pump operation control could be organized in H-n (head vs rpm) coordinates, utilizing pressure transmitters in pressure pipeline and value of rpm from variable speed driver. Safe operation range of the pump has to be limited with system parabolas, which prevents the duty point location outside of the predefined operation area. The particular study demonstrates the engineering approach for pump’s safe operation control development in MATLAB/Simulink environment, which allows to simulate the operation of the pump at different capacities in hydraulic system with variable characteristic and to predefine the conditions for efficient simultaneous pump operation in parallel connection.

AUTOMATIC CALIBRATING SYSTEM FOR PRESSURE TRANSDUCERS

DOEpatents

Amonette, E.L.; Rodgers, G.W.

1958-01-01

An automatic system for calibrating a number of pressure transducers is described. The disclosed embodiment of the invention uses a mercurial manometer to measure the air pressure applied to the transducer. A servo system follows the top of the mercury column as the pressure is changed and operates an analog- to-digital converter This converter furnishes electrical pulses, each representing an increment of pressure change, to a reversible counterThe transducer furnishes a signal at each calibration point, causing an electric typewriter and a card-punch machine to record the pressure at the instant as indicated by the counter. Another counter keeps track of the calibration points so that a number identifying each point is recorded with the corresponding pressure. A special relay control system controls the pressure trend and programs the sequential calibration of several transducers.

Engineering studies of vectorcardiographs in blood pressure measuring systems, appendix 2

NASA Technical Reports Server (NTRS)

Mark, R. G.

1975-01-01

The development of a cardiovascular monitoring system to noninvasively monitor the blood pressure and heart rate using pulse wave velocity was described. The following topics were covered: (1) pulse wave velocity as a measure of arterial blood pressure, (2) diastolic blood pressure and pulse wave velocity in humans, (3) transducer development for blood pressure measuring device, and (4) cardiovascular monitoring system. It was found, in experiments on dogs, that the pulse wave velocity is linearly related to diastolic blood pressure over a wide range of blood pressure and in the presence of many physiological perturbations. A similar relationship was observed in normal, young human males over a moderate range of pressures. Past methods for monitoring blood pressure and a new method based on pulse wave velocity determination were described. Two systems were tested: a Doppler ultrasonic transducer and a photoelectric plethysmograph. A cardiovascular monitoring system was described, including operating instructions.

Lewis Research Center's coal-fired, pressurized, fluidized-bed reactor test facility

NASA Astrophysics Data System (ADS)

Kobak, J. A.; Rollbuhler, R. J.

1981-10-01

A 200-kilowatt-thermal, pressurized, fluidized-bed (PFB) reactor, research test facility was designed, constructed, and operated as part of a NASA-funded project to assess and evaluate the effect of PFB hot-gas effluent on aircraft turbine engine materials that might have applications in stationary-power-plant turbogenerators. Some of the techniques and components developed for this PFB system are described. One of the more important items was the development of a two-in-one, gas-solids separator that removed 95+ percent of the solids in 1600 F to 1900 F gases. Another was a coal and sorbent feed and mixing system for injecting the fuel into the pressurized combustor. Also important were the controls and data-acquisition systems that enabled one person to operate the entire facility. The solid, liquid, and gas sub-systems all had problems that were solved over the 2-year operating time of the facility, which culminated in a 400-hour, hot-gas, turbine test.

Lewis Research Center's coal-fired, pressurized, fluidized-bed reactor test facility

NASA Technical Reports Server (NTRS)

Kobak, J. A.; Rollbuhler, R. J.

1981-01-01

A 200-kilowatt-thermal, pressurized, fluidized-bed (PFB) reactor, research test facility was designed, constructed, and operated as part of a NASA-funded project to assess and evaluate the effect of PFB hot-gas effluent on aircraft turbine engine materials that might have applications in stationary-power-plant turbogenerators. Some of the techniques and components developed for this PFB system are described. One of the more important items was the development of a two-in-one, gas-solids separator that removed 95+ percent of the solids in 1600 F to 1900 F gases. Another was a coal and sorbent feed and mixing system for injecting the fuel into the pressurized combustor. Also important were the controls and data-acquisition systems that enabled one person to operate the entire facility. The solid, liquid, and gas sub-systems all had problems that were solved over the 2-year operating time of the facility, which culminated in a 400-hour, hot-gas, turbine test.

Occupational exposure to nitrous oxide - the role of scavenging and ventilation systems in reducing the exposure level in operating rooms.

PubMed

Krajewski, Wojciech; Kucharska, Malgorzata; Wesolowski, Wiktor; Stetkiewicz, Jan; Wronska-Nofer, Teresa

2007-03-01

The aim of this study was to assess the level of occupational exposure to nitrous oxide (N(2)O) in operating rooms (ORs), as related to different ventilation and scavenging systems used to remove waste anaesthetic gases from the work environment. The monitoring of N(2)O in the air covered 35 ORs in 10 hospitals equipped with different systems for ventilation and anaesthetic scavenging. The examined systems included: natural ventilation with supplementary fresh air provided by a pressure ventilation system (up to 6 air changes/h); pressure and exhaust ventilation systems equipped with ventilation units supplying fresh air to and discharging contaminated air outside the working area (more than 10 air changes/h); complete air-conditioning system with laminar air flow (more than 15 air changes/h). The measurements were carried out during surgical procedures (general anaesthesia induced intravenously and maintained with inhaled N(2)O and sevofluran delivered through cuffed endotracheal tubes) with connected or disconnected air scavenging. Air was collected from the breathing zone of operating personnel continuously through the whole time of anaesthesia to Tedlar((R)) bags, and N(2)O concentrations in air samples were analyzed by adsorption gas chromatography/mass spectrometry. N(2)O levels in excess of the occupational exposure limit (OEL) value of 180mg/m(3) were registered in all ORs equipped with ventilation systems alone. The OEL value was exceeded several times in rooms with natural ventilation plus supplementary pressure ventilations and twice or less in those with pressure/exhaust ventilation systems or air conditioning. N(2)O levels below or within the OEL value were observed in rooms where the system of air conditioning or pressure/exhaust ventilation was combined with scavenging systems. Systems combining natural/pressure ventilation with scavenging were inadequate to maintain N(2)O concentration below the OEL value. Air conditioning and an efficient pressure/exhaust ventilation (above 12 air exchanges/h) together with efficient active scavenging systems are sufficient to sustain N(2)O exposure in ORs at levels below or within the OEL value of 180mg/m(3).

Operator’s Manual. Prototype Heavy Rescue/Fire Fighting Vehicle

DTIC Science & Technology

1980-09-01

system for emergency operation if pressure is lost in either parking or service brake systems . The system is operational automatically and is...controlled by the foot treadle ’sive. It will provide for TWO full brake applications and ONE release. ELECTRICAL SYSTEM A dual battery system is utilized for...cleaner. * Lubricate chassis. . Repack wheel bearings. . Inspect brake system and adjust brakes . . Replace fuel filter. . Check high and low idle.

Verifying Data Integrity of Electronically Scanned Pressure Systems at the NASA Glenn Research Center

NASA Technical Reports Server (NTRS)

Panek, Joseph W.

2001-01-01

The proper operation of the Electronically Scanned Pressure (ESP) System critical to accomplish the following goals: acquisition of highly accurate pressure data for the development of aerospace and commercial aviation systems and continuous confirmation of data quality to avoid costly, unplanned, repeat wind tunnel or turbine testing. Standard automated setup and checkout routines are necessary to accomplish these goals. Data verification and integrity checks occur at three distinct stages, pretest pressure tubing and system checkouts, daily system validation and in-test confirmation of critical system parameters. This paper will give an overview of the existing hardware, software and methods used to validate data integrity.

Development of system design information for carbon dioxide using an amine type sorber

NASA Technical Reports Server (NTRS)

Rankin, R. L.; Roehlich, F.; Vancheri, F.

1971-01-01

Development work on system design information for amine type carbon dioxide sorber is reported. Amberlite IR-45, an aminated styrene divinyl benzene matrix, was investigated to determine the influence of design parameters of sorber particle size, process flow rate, CO2 partial pressure, total pressure, and bed designs. CO2 capacity and energy requirements for a 4-man size system were related mathematically to important operational parameters. Some fundamental studies in CO2 sorber capacity, energy requirements, and process operation were also performed.

Evaluation of the Physiological and Operative Severity Score for the Enumeration of Mortality and Morbidity (POSSUM) scoring system in elderly patients with pressure sores undergoing fasciocutaneous flap-reconstruction.

PubMed

Mizumoto, Kazuo; Morita, Eishin

2009-01-01

The aim of the present study was to predict operative morbidity in elderly patients with deep pressure sores by using the Physiological and Operative Severity Score for the Enumeration of Mortality and Morbidity (POSSUM) scoring system. Fifteen patients over 70 years old were retrospectively reviewed who had undergone gluteus maximus fasciocutaneous flap-reconstruction for pressure sores of the sacral region from 1 April 2005 to 31 March 2007. Complications were seen in six cases (40%) after operation. Four were wound infection, one was chest infection and another was septicemia. The subjects were divided into two groups by the presence (complicated group) or absence (non-complicated group) of postoperative complications. Each item of physiological scores, physiological score (PS), operative severity score (OS) and predicted morbidity rate (R) were calculated and compared between two groups. As a result, hemoglobin (P = 0.0276), PS (P = 0.0023) and R (P = 0.0078) differed significantly between the two groups. It is noteworthy that the PS were over 25 in all of the complicated group, but in only one of nine in the non-complicated group (P = 0.0014). Our study suggests that, for pressure sores in the sacral region in elderly patients, gluteus maximus fasciocutaneous flap-reconstruction can be employed in patients whose PS are under 24 in the POSSUM scoring system.

Cryogenic Pressure Calibrator for Wide Temperature Electronically Scanned (ESP) Pressure Modules

NASA Technical Reports Server (NTRS)

Faulcon, Nettie D.

2001-01-01

Electronically scanned pressure (ESP) modules have been developed that can operate in ambient and in cryogenic environments, particularly Langley's National Transonic Facility (NTF). Because they can operate directly in a cryogenic environment, their use eliminates many of the operational problems associated with using conventional modules at low temperatures. To ensure the accuracy of these new instruments, calibration was conducted in a laboratory simulating the environmental conditions of NTF. This paper discusses the calibration process by means of the simulation laboratory, the system inputs and outputs and the analysis of the calibration data. Calibration results of module M4, a wide temperature ESP module with 16 ports and a pressure range of +/- 4 psid are given.

Real-Time Model-Based Leak-Through Detection within Cryogenic Flow Systems

NASA Technical Reports Server (NTRS)

Walker, M.; Figueroa, F.

2015-01-01

The timely detection of leaks within cryogenic fuel replenishment systems is of significant importance to operators on account of the safety and economic impacts associated with material loss and operational inefficiencies. Associated loss in control of pressure also effects the stability and ability to control the phase of cryogenic fluids during replenishment operations. Current research dedicated to providing Prognostics and Health Management (PHM) coverage of such cryogenic replenishment systems has focused on the detection of leaks to atmosphere involving relatively simple model-based diagnostic approaches that, while effective, are unable to isolate the fault to specific piping system components. The authors have extended this research to focus on the detection of leaks through closed valves that are intended to isolate sections of the piping system from the flow and pressurization of cryogenic fluids. The described approach employs model-based detection of leak-through conditions based on correlations of pressure changes across isolation valves and attempts to isolate the faults to specific valves. Implementation of this capability is enabled by knowledge and information embedded in the domain model of the system. The approach has been used effectively to detect such leak-through faults during cryogenic operational testing at the Cryogenic Testbed at NASA's Kennedy Space Center.

49 CFR 195.428 - Overpressure safety devices and overfill protection systems.

Code of Federal Regulations, 2010 CFR

2010-10-01

... months, but at least twice each calendar year, inspect and test each pressure limiting device, relief... reliability of operation for the service in which it is used. (b) In the case of relief valves on pressure breakout tanks containing highly volatile liquids, each operator shall test each valve at intervals not...

33 CFR 154.850 - Operational requirements.

Code of Federal Regulations, 2010 CFR

2010-07-01

... system that meets the requirements of 46 CFR 39.20-9(b) must not be connected to an overfill sensor... by § 154.810(a) of this subpart must not be opened until the pressure at the facility vapor connection exceeds the pressure on the downstream side of the remotely operated cargo vapor shutoff valve. (f...

Pressure Swing Adsorption in the Unit Operations Laboratory

ERIC Educational Resources Information Center

Ganley, Jason

2018-01-01

This paper describes a student laboratory in the Unit Operations Laboratory at the Colorado School of Mines: air separation by pressure swing adsorption. The flexibility of the system enables students to study the production of enriched nitrogen or oxygen streams. Automatic data acquisition permits the study of cycle steps and performance.…

Automated Cryocooler Monitor and Control System Software

NASA Technical Reports Server (NTRS)

Britchcliffe, Michael J.; Conroy, Bruce L.; Anderson, Paul E.; Wilson, Ahmad

2011-01-01

This software is used in an automated cryogenic control system developed to monitor and control the operation of small-scale cryocoolers. The system was designed to automate the cryogenically cooled low-noise amplifier system described in "Automated Cryocooler Monitor and Control System" (NPO-47246), NASA Tech Briefs, Vol. 35, No. 5 (May 2011), page 7a. The software contains algorithms necessary to convert non-linear output voltages from the cryogenic diode-type thermometers and vacuum pressure and helium pressure sensors, to temperature and pressure units. The control function algorithms use the monitor data to control the cooler power, vacuum solenoid, vacuum pump, and electrical warm-up heaters. The control algorithms are based on a rule-based system that activates the required device based on the operating mode. The external interface is Web-based. It acts as a Web server, providing pages for monitor, control, and configuration. No client software from the external user is required.

Performance of the active sidewall boundary-layer removal system for the Langley 0.3-meter Transonic Cryogenic Tunnel

NASA Technical Reports Server (NTRS)

Balakrishna, S.; Kilgore, W. Allen; Murthy, A. V.

1989-01-01

A performance evaluation of an active sidewall boundary-layer removal system for the Langley 0.3-m Transonic Cryogenic Tunnel (TCT) was evaluated in 1988. This system uses a compressor and two throttling digital valves to control the boundary-layer mass flow removal from the tunnel. The compressor operates near the maximum pressure ratio for all conditions. The system uses a surge prevention and flow recirculation scheme. A microprocessor based controller is used to provide the necessary mass flow and compressor pressure ratio control. Initial tests on the system indicated problems in realizing smooth mass flow control while running the compressor at high speed and high pressure ratios. An alternate method has been conceived to realize boundary-layer mass flow control which avoids the recirculation of the compressor mass flow and operation near the compressor surge point. This scheme is based on varying the speed of the compressor for a sufficient pressure ratio to provide needed mass flow removal. The system has a mass flow removal capability of about 10 percent of test section flow at M = 0.3 and 4 percent at M = 0.8. The system performance has been evaluated in the form of the compressor map, and compressor tunnel interface characteristics covering most of the 0.3-m TCT operational envelope.

An on-line monitoring system for oil-film, pressure and temperature distributions in large-scale hydro-generator bearings

NASA Astrophysics Data System (ADS)

Höbel, M.; Haffner, K.

1999-05-01

Instrumentation that allows the behaviour of a hydro-generator thrust bearing to be monitored during operation is described. The measurement system was developed at the Asea Brown Boveri corporate research centre in Switzerland and was tested under realistic operating conditions at the Harbin Electric Machinery Company bearing-testing facility in the People's Republic of China. Newly developed fibre-optical proximity probes were used for the on-line monitoring of the thin oil film between the static and rotating parts of the bearing. These sensors are based on a back-reflection technique and can be used for various target materials such as Babbitt and Teflon. The monitoring system comprises about 120 temperature sensors, four pressure sensors and five optical oil-film thickness sensors. Temperature sensors are installed at specific static locations, whereas pressure and oil-film sensors are positioned in the runner and generate data during rotation. A special feature of the monitoring equipment is its on-line processing capability. Digital signal processors operating in parallel handle pressure and oil-film thickness data. Important measurement parameters such as the maximum pressure, maximum temperature and minimum oil-film thickness are displayed on-line. Detailed three-dimensional temperature information on one of the load segments can be obtained from subsequent off-line data analysis. The system also calculates two-dimensional plots of the oil-film thickness and pressure for most of the 12 load segments.

High Pressure Coolant Injection (HPCI) System Risk-Based Inspection Guide for Browns Ferry Nuclear Power Station

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

Wong, S.; DiBiasio, A.; Gunther, W.

1993-09-01

The High Pressure Coolant Injection (HPCI) system has been examined from a risk perspective. A System Risk-Based Inspection Guide (S-RIG) has been developed as an aid to HPCI system inspections at the Browns Ferry Nuclear Power Plant, Units 1, 2 and 3. The role of. the HPCI system in mitigating accidents is discussed in this S-RIG, along with insights on identified risk-based failure modes which could prevent proper operation of the system. The S-RIG provides a review of industry-wide operating experience, including plant-specific illustrative examples to augment the PRA and operational considerations in identifying a catalogue of basic PRA failuremore » modes for the HPCI system. It is designed to be used as a reference for routine inspections, self-initiated safety system functional inspections (SSFIs), and the evaluation of risk significance of component failures at the nuclear power plant.« less

Pilot Emergency Tutoring System for F-4 Aircraft Fuel System Malfunction Using Means-Ends Analysis

DTIC Science & Technology

1990-06-01

pulled , and wing transfer pressure is normal. What operator do you choose? For example: type look_at INDICATOR for looked_at(INDICATOR) type set...cb internal wing transfer is pulled , and wing transfer pressure is normal. What operator do you choose? For example: type look_at INDICATOR for...at, external transfer is off, internal wing transfer is stop trans, refuel probe is extended, cb internal wing transfer is pulled ,and wing

Fiber Optic Handpiece Illumination Systems

DTIC Science & Technology

1989-01-01

only available from the manufacturer. Method of Light Activation Three systems are currently employed: 1. Handpiece Air Pressure Switch . The...Average Easy 3. Type of lamp (note brand and part #): 4. Method of light activation: Touch Air pressure Switch 5. Will it activate while the operator

Hydraulic Evaluation of Marmet Lock Filling and Emptying System, Kanawha River, West Virginia

DTIC Science & Technology

2015-04-01

the culvert system was considered important because the lock design is a new In-chamber Longitudinal Culvert System (ILCS) that is found only on...emptying system during locking operations. A numerical model of the lock culvert system was developed to provide velocity and pressure information...35 6.1.3 Pressure on Inside of Culvert Bend

Johnson Space Center's Regenerative Life Support Systems Test Bed

NASA Technical Reports Server (NTRS)

Barta, D. J.; Henninger, D. L.

1996-01-01

The Regenerative Life Support Systems (RLSS) Test Bed at NASA's Johnson Space Center is an atmospherically closed, controlled environment facility for human testing of regenerative life support systems using higher plants in conjunction with physicochemical life support systems. The facility supports NASA's Advanced Life Support (ALS) Program. The facility is comprised of two large scale plant growth chambers, each with approximately 11 m2 growing area. The root zone in each chamber is configurable for hydroponic or solid media plant culture systems. One of the two chambers, the Variable Pressure Growth Chamber (VPGC), is capable of operating at lower atmospheric pressures to evaluate a range of environments that may be used in a planetary surface habitat; the other chamber, the Ambient Pressure Growth Chamber (APGC) operates at ambient atmospheric pressure. The air lock of the VPGC is currently being outfitted for short duration (1 to 15 day) human habitation at ambient pressures. Testing with and without human subjects will focus on 1) integration of biological and physicochemical air and water revitalization systems; 2) effect of atmospheric pressure on system performance; 3) planetary resource utilization for ALS systems, in which solid substrates (simulated planetary soils or manufactured soils) are used in selected crop growth studies; 4) environmental microbiology and toxicology; 5) monitoring and control strategies; and 6) plant growth systems design. Included are descriptions of the overall design of the test facility, including discussions of the atmospheric conditioning, thermal control, lighting, and nutrient delivery systems.

Johnson Space Center's Regenerative Life Support Systems Test Bed

NASA Astrophysics Data System (ADS)

Barta, D. J.; Henninger, D. L.

1996-01-01

The Regenerative Life Support Systems (RLSS) Test Bed at NASA's Johnson Space Center is an atmospherically closed, controlled environment facility for human testing of regenerative life support systems using higher plants in conjunction with physicochemical life support systems. The facility supports NASA's Advanced Life Support (ALS) Program. The facility is comprised of two large scale plant growth chambers, each with approximately 11 m^2 growing area. The root zone in each chamber is configurable for hydroponic or solid media plant culture systems. One of the two chambers, the Variable Pressure Growth Chamber (VPGC), is capable of operating at lower atmospheric pressures to evaluate a range of environments that may be used in a planetary surface habitat; the other chamber, the Ambient Pressure Growth Chamber (APGC) operates at ambient atmospheric pressure. The air lock of the VPGC is currently being outfitted for short duration (1 to 15 day) human habitation at ambient pressures. Testing with and without human subjects will focus on 1) integration of biological and physicochemical air and water revitalization systems; 2) effect of atmospheric pressure on system performance; 3) planetary resource utilization for ALS systems, in which solid substrates (simulated planetary soils or manufactured soils) are used in selected crop growth studies; 4) environmental microbiology and toxicology; 5) monitoring and control strategies; and 6) plant growth systems design. Included are descriptions of the overall design of the test facility, including discussions of the atmospheric conditioning, thermal control, lighting, and nutrient delivery systems.

A modernized high-pressure heater protection system for nuclear and thermal power stations

NASA Astrophysics Data System (ADS)

Svyatkin, F. A.; Trifonov, N. N.; Ukhanova, M. G.; Tren'kin, V. B.; Koltunov, V. A.; Borovkov, A. I.; Klyavin, O. I.

2013-09-01

Experience gained from operation of high-pressure heaters and their protection systems serving to exclude ingress of water into the turbine is analyzed. A formula for determining the time for which the high-pressure heater shell steam space is filled when a rupture of tubes in it occurs is analyzed, and conclusions regarding the high-pressure heater design most advisable from this point of view are drawn. A typical structure of protection from increase of water level in the shell of high-pressure heaters used in domestically produced turbines for thermal and nuclear power stations is described, and examples illustrating this structure are given. Shortcomings of components used in the existing protection systems that may lead to an accident at the power station are considered. A modernized protection system intended to exclude the above-mentioned shortcomings was developed at the NPO Central Boiler-Turbine Institute and ZioMAR Engineering Company, and the design solutions used in this system are described. A mathematical model of the protection system's main elements (the admission and check valves) has been developed with participation of specialists from the St. Petersburg Polytechnic University, and a numerical investigation of these elements is carried out. The design version of surge tanks developed by specialists of the Central Boiler-Turbine Institute for excluding false operation of the high-pressure heater protection system is proposed.

Pressure-relieving properties of a intra-operative warming device.

PubMed

Baker, E A; Leaper, D J

2003-04-01

The primary objective of this study was to determine differences in interface pressure between four mattress combinations: a standard operating table mattress, a pressure-relieving gel pad and an under-patient warming device set at 38 degrees C (Pegasus Inditherm System) and at ambient temperature. The secondary objective was to determine whether the warming device remains stable in extreme surgical positions. Interface pressures obtained with all four combinations were measured in 10 healthy volunteers using force sensing array technology. The warming device demonstrated better or equivalent pressure relief when compared with the standard gel pad. There was no significant difference in subject position 'shift' between the mattress, the gel pad and the warming device for either the Trendelenberg or reverse Trendelenberg positions. Both pressure-relieving mattresses and warming reduce intra-operative pressure damage. A mattress with both properties may further reduce pressure damage postoperatively. The warming device used in this study appears stable--subject 'slippage' was minimal in extreme positions. Research needs to be conducted among real anaesthetised patients to support these conclusions.

40 CFR 63.3546 - How do I establish the emission capture system and add-on control device operating limits during...

Code of Federal Regulations, 2010 CFR

2010-07-01

... system and add-on control device operating limits during the performance test? 63.3546 Section 63.3546... device or system of multiple capture devices. The average duct static pressure is the maximum operating... Add-on Controls Option § 63.3546 How do I establish the emission capture system and add-on control...

40 CFR 63.3546 - How do I establish the emission capture system and add-on control device operating limits during...

Code of Federal Regulations, 2011 CFR

2011-07-01

... system and add-on control device operating limits during the performance test? 63.3546 Section 63.3546... device or system of multiple capture devices. The average duct static pressure is the maximum operating... Add-on Controls Option § 63.3546 How do I establish the emission capture system and add-on control...

Program operational summary: Operational 90 day manned test of a regenerative life support system

NASA Technical Reports Server (NTRS)

Jackson, J. K.; Wamsley, J. R.; Bonura, M. S.; Seeman, J. S.

1972-01-01

An operational 90-day manned test of a regenerative life support system was successfully completed. This test was performed with a crew of four carefully selected and trained men in a space station simulator (SSS) which had a two gas atmosphere maintained at a total pressure of 68.9, 10 psia, and composed of oxygen at a partial pressure of 3.05 psia with nitrogen as the diluent. The test was planned to provide data on regenerative life support subsystems and on integrated system operations in a closed ecology, similar to that of a space station. All crew equipment and expendables were stored onboard at the start of the mission to eliminate the need for pass-in operations. The significant accomplishments of the test, some of the pertinent test results, some of the problem areas, and conclusions are presented.

The optimization of design parameters for surge relief valve for pipeline systems

NASA Astrophysics Data System (ADS)

Kim, Hyunjun; Hur, Jisung; Kim, Sanghyun

2017-06-01

Surge is an abnormal pressure which induced by rapid changes of flow rate in pipeline systems. In order to protect pipeline system from the surge pressure, various hydraulic devices have been developed. Surge-relief valve(SRV) is one of the widely applied devices to control surge due to its feasibility in application, efficiency and cost-effectiveness. SRV is designed to automatically open under abnormal pressure and discharge the flow and makes pressure of the system drop to the allowable level. The performance of the SRV is influenced by hydraulics. According to previous studies, there are several affecting factors which determine performance of the PRV such as design parameters (e.g. size of the valve), system parameters (e.g. number of the valves and location of the valve), and operation parameters (e.g. set point and operation time). Therefore, the systematic consideration for factors affecting performance of SRV is required for the proper installation of SRV in the system. In this study, methodology for finding optimum parameters of the SRV is explored through the integration of Genetic Algorithm(GA) into surge analysis.

Airborne particle dispersion to an operating room environment during sliding and hinged door opening.

PubMed

Sadrizadeh, Sasan; Pantelic, Jovan; Sherman, Max; Clark, Jordan; Abouali, Omid

2018-03-08

Operating rooms (ORs) are usually over-pressurized in order to prevent the penetration of contaminated air and the consequent risk of surgical site infection. However, a door-opening can result in the rapid disappearance of pressure and contaminants can then easily penetrate into the surgical zone. Therefore, a broad knowledge and understanding of OR ventilation systems and their protective potential is essential for optimizing the surgical environment. This study investigated the air quality and level of airborne particles during a single and multiple door-opening cycles in an operating room supplied by a turbulent-mixing ventilation system. The exploration was carried out numerically using computational fluid dynamics. Model validation was performed to ensure the validity of the achieved results. The OR was initially over-pressurized by approximately 15Pa, relative to the adjacent corridors. Both sliding and hinged doors were simulated and compared. Penetration of bacteria carrying particles from the corridors to the OR can be successfully restricted by using a positive-pressure system. However, the results clearly indicate that frequent door opening can interfere with airflow ventilation systems, alter the pressure gradient, and increase the infection risk for the patient undergoing surgical intervention. Door-opening disturbs the airflow field and could result in containment failure. Copyright © 2018 The Authors. Published by Elsevier Ltd.. All rights reserved.

Transient analysis of gas transport in anode channel of a polymer electrolyte membrane fuel cell with dead-ended anode under pressure swing operation

NASA Astrophysics Data System (ADS)

Ichikawa, Yasushi; Oshima, Nobuyuki; Tabuchi, Yuichiro; Ikezoe, Keigo

2014-12-01

Further cost reduction is a critical issue for commercialization of fuel-cell electric vehicles (FCEVs) based on polymer electrolyte fuel cells (PEFCs). The cost of the fuel-cell system is driven by the multiple parts required to maximize stack performance and maintain durability and robustness. The fuel-cell system of the FCEV must be simplified while maintaining functionality. The dead-ended anode is considered as a means of simplification in this study. Generally, if hydrogen is supplied under constant pressure during dead-ended operation, stable power generation is impossible because of accumulation of liquid water produced by power generation and of nitrogen via leakage from the cathode through the membrane. Herein, pressure oscillation is applied to address this issue. Empirical and CFD data are employed to elucidate the mechanism of stable power generation using the pressure swing supply. Simultaneous and time-continuous measurements of the current distribution and gas concentration distribution are also conducted. The results demonstrate that the nitrogen concentration in the anode channel under pressure constant operation differs from that under pressure swing supply conditions. The transient two-dimensional CFD results indicate that oscillatory flow is generated by pressure swing supply, which periodically sweeps out nitrogen from the active area, resulting in stable power generation.

Bidirectional Pressure-Regulator System

NASA Technical Reports Server (NTRS)

Burke, Kenneth; Miller, John R.

2008-01-01

A bidirectional pressure-regulator system has been devised for use in a regenerative fuel cell system. The bidirectional pressure-regulator acts as a back-pressure regulator as gas flows through the bidirectional pressure-regulator in one direction. Later, the flow of gas goes through the regulator in the opposite direction and the bidirectional pressure-regulator operates as a pressure- reducing pressure regulator. In the regenerative fuel cell system, there are two such bidirectional regulators, one for the hydrogen gas and another for the oxygen gas. The flow of gases goes from the regenerative fuel cell system to the gas storage tanks when energy is being stored, and reverses direction, flowing from the storage tanks to the regenerative fuel cell system when the stored energy is being withdrawn from the regenerative fuel cell system. Having a single bidirectional regulator replaces two unidirectional regulators, plumbing, and multiple valves needed to reverse the flow direction. The term "bidirectional" refers to both the bidirectional nature of the gas flows and capability of each pressure regulator to control the pressure on either its upstream or downstream side, regardless of the direction of flow.

Test Data Analysis of a Spray Bar Zero-Gravity Liquid Hydrogen Vent System for Upper Stages

NASA Technical Reports Server (NTRS)

Hedayat, A.; Bailey, J. W.; Hastings, L. J.; Flachbart, R. H.

2003-01-01

To support development of a zero-gravity pressure control capability for liquid hydrogen (LH2), a series of thermodynamic venting system (TVS) tests was conducted in 1996 and 1998 using the Marshall Space Flight Center (MSFC) multipurpose hydrogen test bed (MHTB). These tests were performed with ambient heat leaks =20 and 50 W for tank fill levels of 90%, 50%, and 25%. TVS performance testing revealed that the spray bar was highly effective in providing tank pressure control within a 7-kPa band (131-138 Wa), and complete destratification of the liquid and the ullage was achieved with all test conditions. Seven of the MHTB tests were correlated with the TVS performance analytical model. The tests were selected to encompass the range of tank fill levels, ambient heat leaks, operational modes, and ullage pressurants. The TVS model predicted ullage pressure and temperature and bulk liquid saturation pressure and temperature obtained from the TVS model were compared with the test data. During extended self-pressurization periods, following tank lockup, the model predicted faster pressure rise rates than were measured. However, once the system entered the cyclic mixing/venting operational mode, the modeled and measured data were quite similar.

System for detecting operating errors in a variable valve timing engine using pressure sensors

DOEpatents

Wiles, Matthew A.; Marriot, Craig D

2013-07-02

A method and control module includes a pressure sensor data comparison module that compares measured pressure volume signal segments to ideal pressure volume segments. A valve actuation hardware remedy module performs a hardware remedy in response to comparing the measured pressure volume signal segments to the ideal pressure volume segments when a valve actuation hardware failure is detected.

[SURGICAL TACTICS IN CHRONIC PANCREATITIS WITH SIGNS OF BILIARY HYPERTENSION].

PubMed

Usenko, O Yu; Kopchak, V M; Pylypchuk, V I; Kopchak, K V; Andronik, S V

2015-08-01

The results of treatment of 84 patients for chronic pancreatitis with the biliary hypertension signs were depicted. In 83 patients operative interventions were performed, and in 1--positive results were achieved after pancreatic cyst puncture under ultrasonographic control. In 51 patients the conduction of Frey operation have permitted to achieve a lower pressure inside biliary system, in 25--the additional procedures were applied for a biliary hypertension elimination. In 20 patients a method of pressure measurement in biliary system was used.

Combustion performance and heat transfer characterization of LOX/hydrocarbon type propellants. Task 3: Data dump

NASA Technical Reports Server (NTRS)

Hart, S. W.

1982-01-01

A preliminary characterization of Orbital Maneuvering System (OMS) and Reaction Control System (RCS) engine point designs over a range of thrust and chamber pressure for several hydrocarbon fuels is reported. OMS and RCS engine point designs were established in two phases comprising baseline and parametric designs. Interface pressures, performance and operating parameters, combustion chamber cooling and turboprop requirements, component weights and envelopes, and propellant conditioning requirements for liquid to vapor phase engine operation are defined.

Calibrating pressure switch

NASA Technical Reports Server (NTRS)

Smith, N. J. (Inventor)

1968-01-01

A pressure switch assembly comprising a body portion and a switch mechanism having a contact element operable between opposite limit positions is described. A diaphragm chamber is provided in the body portion which mounts therein a system diaphragm and a calibration diaphragm which are of generally the same configuration and having outer faces conforming to the inner and outer walls of the diaphragm chamber. The space between the inner faces of the diaphragms defines a first chamber section and the space between the outer face of one of the diaphragms and the outer wall of the diaphragm chamber defines a second chamber section. The body portion includes a system pressure port communicating with one of the chamber sections and a calibration pressure port communicating with the other chamber section. An actuator connected to one of the diaphragms and the contact element of the switch operates upon pressure change in the diaphragm sections to move said contact element between limit positions.

Hydrogasification reactor and method of operating same

DOEpatents

Hobbs, Raymond; Karner, Donald; Sun, Xiaolei; Boyle, John; Noguchi, Fuyuki

2013-09-10

The present invention provides a system and method for evaluating effects of process parameters on hydrogasification processes. The system includes a hydrogasification reactor, a pressurized feed system, a hopper system, a hydrogen gas source, and a carrier gas source. Pressurized carbonaceous material, such as coal, is fed to the reactor using the carrier gas and reacted with hydrogen to produce natural gas.

Simulation of Unique Pressure Changing Steps and Situations in Psa Processes

NASA Technical Reports Server (NTRS)

Ebner, Armin D.; Mehrotra, Amal; Knox, James C.; LeVan, Douglas; Ritter, James A.

2007-01-01

A more rigorous cyclic adsorption process simulator is being developed for use in the development and understanding of new and existing PSA processes. Unique features of this new version of the simulator that Ritter and co-workers have been developing for the past decade or so include: multiple absorbent layers in each bed, pressure drop in the column, valves for entering and exiting flows and predicting real-time pressurization and depressurization rates, ability to account for choked flow conditions, ability to pressurize and depressurize simultaneously from both ends of the columns, ability to equalize between multiple pairs of columns, ability to equalize simultaneously from both ends of pairs of columns, and ability to handle very large pressure ratios and hence velocities associated with deep vacuum systems. These changes to the simulator now provide for unique opportunities to study the effects of novel pressure changing steps and extreme process conditions on the performance of virtually any commercial or developmental PSA process. This presentation will provide an overview of the cyclic adsorption process simulator equations and algorithms used in the new adaptation. It will focus primarily on the novel pressure changing steps and their effects on the performance of a PSA system that epitomizes the extremes of PSA process design and operation. This PSA process is a sorbent-based atmosphere revitalization (SBAR) system that NASA is developing for new manned exploration vehicles. This SBAR system consists of a 2-bed 3-step 3-layer system that operates between atmospheric pressure and the vacuum of space, evacuates from both ends of the column simultaneously, experiences choked flow conditions during pressure changing steps, and experiences a continuously changing feed composition, as it removes metabolic CO2 and H20 from a closed and fixed volume, i.e., the spacecraft cabin. Important process performance indicators of this SBAR system are size, and the corresponding CO2 and H20 removal efficiencies, and N2 and O2 loss rates. Results of the fundamental behavior of this PSA process during extreme operating conditions will be presented and discussed.

Enhanced methods for operating refueling station tube-trailers to reduce refueling cost

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

Elgowainy, Amgad; Reddi, Krishna

A method and apparatus are provided for operating a refueling station including source tube-trailers and at least one compressor to reduce refueling cost. The refueling station includes a gaseous fuel supply source including a plurality of tanks on a tube trailer coupled to a first control unit, and high pressure buffer storage having predefined capacity coupled to a second control unit and the first tanks by a pressure control valve and the first control unit, and at least one compressor. The refueling station is operated at different modes depending on a state of the refueling station at the beginning ofmore » each operational mode. The refueling system is assessed at the end of each operational mode to identify the state of the system and select a next mode of operation. The operational modes include consolidating hydrogen, or any gaseous fuel, within the tubes mounted on the trailer.« less

Control system for an artificial heart

NASA Technical Reports Server (NTRS)

Gebben, V. D.; Webb, J. A., Jr.

1970-01-01

Inexpensive industrial pneumatic components are combined to produce control system to drive sac-type heart-assistance blood pump with controlled pulsatile pressure that makes pump rate of flow sensitive to venous /atrial/ pressure, while stroke is centered about set operating point and pump is synchronized with natural heart.

High Pressure Coolant Injection system risk-based inspection guide for Hatch Nuclear Power Station

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

DiBiasio, A.M.

1993-05-01

A review of the operating experience for the High Pressure Coolant Injection (HPCI) system at the Hatch Nuclear Power Station, Units 1 and 2, is described in this report. The information for this review was obtained from Hatch Licensee Event Reports (LERs) that were generated between 1980 and 1992. These LERs have been categorized into 23 failure modes that have been prioritized based on probabilistic risk assessment considerations. In addition, the results of the Hatch operating experience review have been compared with the results of a similar, industry wide operating, experience review. This comparison provides an indication of areas inmore » the Hatch HPCI system that should be given increased attention in the prioritization of inspection resources.« less

Cell module and fuel conditioner development

NASA Technical Reports Server (NTRS)

Feret, J. M.

1981-01-01

A phosphoric acid fuel cell (PAFC) stack design having a 10 kW power rating for operation at higher than atmospheric pressure based on the existing Mark II design configuration is described. Functional analysis, trade studies and thermodynamic cycle analysis for requirements definition and system operating parameter selection purposes were performed. Fuel cell materials and components, and performance testing and evaluation of the repeating electrode components were characterized. The state of the art manufacturing technology for all fuel cell components and the fabrication of short stacks of various sites were established. A 10 kW PAFC stack design for higher pressure operation utilizing the top down systems engineering aproach was developed.

Electrical Pressurization Concept for the Orion MPCV European Service Module Propulsion System

NASA Technical Reports Server (NTRS)

Meiss, Jan-Hendrik; Weber, Jorg; Ierardo, Nicola; Quinn, Frank D.; Paisley, Jonathan

2015-01-01

The paper presents the design of the pressurization system of the European Service Module (ESM) of the Orion Multi-Purpose Crew Vehicle (MPCV). Being part of the propulsion subsystem, an electrical pressurization concept is implemented to condition propellants according to the engine needs via a bang-bang regulation system. Separate pressurization for the oxidizer and the fuel tank permits mixture ratio adjustments and prevents vapor mixing of the two hypergolic propellants during nominal operation. In case of loss of pressurization capability of a single side, the system can be converted into a common pressurization system. The regulation concept is based on evaluation of a set of tank pressure sensors and according activation of regulation valves, based on a single-failure tolerant weighting of three pressure signals. While regulation is performed on ESM level, commanding of regulation parameters as well as failure detection, isolation and recovery is performed from within the Crew Module, developed by Lockheed Martin Space System Company. The overall design and development maturity presented is post Preliminary Design Review (PDR) and reflects the current status of the MPCV ESM pressurization system.

Experimental Assessment of the Reciprocating Feed System

NASA Technical Reports Server (NTRS)

Eddleman, David E.; Blackmon, James B.; Morton, Christopher D.

2006-01-01

The primary goal of this project was to design, construct, and test a full scale, high pressure simulated propellant feed system test bed that could evaluate the ability of the Reciprocating Feed System (RFS) to provide essentially constant flow rates and pressures to a rocket engine. The two key issues addressed were the effects of the transition of the drain cycle from tank to tank and the benefits of other hardware such as accumulators to provide a constant pressure flow rate out of the RFS. The test bed provided 500 psi flow at rates of the order of those required for engines in the 20,000 lbf thrust class (e.g., 20 to 40 lb/sec). A control system was developed in conjunction with the test article and automated system operation was achieved. Pre-test planning and acceptance activities such as a documented procedure and hazard analysis were conducted and the operation of the test article was approved by, and conducted in coordination with, appropriate NASA Marshall Space Flight Center personnel under a Space Act Agreement. Tests demonstrated successful control of flow rates and pressures.

Indirect-fired gas turbine dual fuel cell power cycle

DOEpatents

Micheli, Paul L.; Williams, Mark C.; Sudhoff, Frederick A.

1996-01-01

A fuel cell and gas turbine combined cycle system which includes dual fuel cell cycles combined with a gas turbine cycle wherein a solid oxide fuel cell cycle operated at a pressure of between 6 to 15 atms tops the turbine cycle and is used to produce CO.sub.2 for a molten carbonate fuel cell cycle which bottoms the turbine and is operated at essentially atmospheric pressure. A high pressure combustor is used to combust the excess fuel from the topping fuel cell cycle to further heat the pressurized gas driving the turbine. A low pressure combustor is used to combust the excess fuel from the bottoming fuel cell to reheat the gas stream passing out of the turbine which is used to preheat the pressurized air stream entering the topping fuel cell before passing into the bottoming fuel cell cathode. The CO.sub.2 generated in the solid oxide fuel cell cycle cascades through the system to the molten carbonate fuel cell cycle cathode.

NEXT Propellant Management System Integration With Multiple Ion Thrusters

NASA Technical Reports Server (NTRS)

Sovey, James S.; Soulas, George C.; Herman, Daniel A.

2011-01-01

As a critical part of the NEXT test validation process, a multiple-string integration test was performed on the NEXT propellant management system and ion thrusters. The objectives of this test were to verify that the PMS is capable of providing stable flow control to multiple thrusters operating over the NEXT system throttling range and to demonstrate to potential users that the NEXT PMS is ready for transition to flight. A test plan was developed for the sub-system integration test for verification of PMS and thruster system performance and functionality requirements. Propellant management system calibrations were checked during the single and multi-thruster testing. The low pressure assembly total flow rates to the thruster(s) were within 1.4 percent of the calibrated support equipment flow rates. The inlet pressures to the main, cathode, and neutralizer ports of Thruster PM1R were measured as the PMS operated in 1-thruster, 2-thruster, and 3-thruster configurations. It was found that the inlet pressures to Thruster PM1R for 2-thruster and 3-thruster operation as well as single thruster operation with the PMS compare very favorably indicating that flow rates to Thruster PM1R were similar in all cases. Characterizations of discharge losses, accelerator grid current, and neutralizer performance were performed as more operating thrusters were added to the PMS. There were no variations in these parameters as thrusters were throttled and single and multiple thruster operations were conducted. The propellant management system power consumption was at a fixed voltage to the DCIU and a fixed thermal throttle temperature of 75 C. The total power consumed by the PMS was 10.0, 17.9, and 25.2 W, respectively, for single, 2-thruster, and 3-thruster operation with the PMS. These sub-system integration tests of the PMS, the DCIU Simulator, and multiple thrusters addressed, in part, the NEXT PMS and propulsion system performance and functionality requirements.

46 CFR 28.405 - Hydraulic equipment.

Code of Federal Regulations, 2013 CFR

2013-10-01

... than four times the system maximum operating pressure. (c) Each hydraulic system must be equipped with... 46 Shipping 1 2013-10-01 2013-10-01 false Hydraulic equipment. 28.405 Section 28.405 Shipping... Operate With More Than 16 Individuals on Board § 28.405 Hydraulic equipment. (a) Each hydraulic system...

46 CFR 28.405 - Hydraulic equipment.

Code of Federal Regulations, 2010 CFR

2010-10-01

... than four times the system maximum operating pressure. (c) Each hydraulic system must be equipped with... 46 Shipping 1 2010-10-01 2010-10-01 false Hydraulic equipment. 28.405 Section 28.405 Shipping... Operate With More Than 16 Individuals on Board § 28.405 Hydraulic equipment. (a) Each hydraulic system...

46 CFR 28.405 - Hydraulic equipment.

Code of Federal Regulations, 2014 CFR

2014-10-01

... than four times the system maximum operating pressure. (c) Each hydraulic system must be equipped with... 46 Shipping 1 2014-10-01 2014-10-01 false Hydraulic equipment. 28.405 Section 28.405 Shipping... Operate With More Than 16 Individuals on Board § 28.405 Hydraulic equipment. (a) Each hydraulic system...

46 CFR 28.405 - Hydraulic equipment.

Code of Federal Regulations, 2011 CFR

2011-10-01

... than four times the system maximum operating pressure. (c) Each hydraulic system must be equipped with... 46 Shipping 1 2011-10-01 2011-10-01 false Hydraulic equipment. 28.405 Section 28.405 Shipping... Operate With More Than 16 Individuals on Board § 28.405 Hydraulic equipment. (a) Each hydraulic system...

46 CFR 28.405 - Hydraulic equipment.

Code of Federal Regulations, 2012 CFR

2012-10-01

... than four times the system maximum operating pressure. (c) Each hydraulic system must be equipped with... 46 Shipping 1 2012-10-01 2012-10-01 false Hydraulic equipment. 28.405 Section 28.405 Shipping... Operate With More Than 16 Individuals on Board § 28.405 Hydraulic equipment. (a) Each hydraulic system...

Pressure Pulsation in a High Head Francis Turbine Operating at Variable Speed

NASA Astrophysics Data System (ADS)

Sannes, D. B.; Iliev, I.; Agnalt, E.; Dahlhaug, O. G.

2018-06-01

This paper presents the preliminary work of the master thesis of the author, written at the Norwegian University of Science and Technology. Today, many Francis turbines experience formations of cracks in the runner due to pressure pulsations. This can eventually cause failure. One way to reduce this effect is to change the operation point of the turbine, by utilizing variable speed technology. This work presents the results from measurements of the Francis turbine at the Waterpower Laboratory at NTNU. Measurements of pressure pulsations and efficiency were done for the whole operating range of a high head Francis model turbine. The results will be presented in a similar diagram as the Hill Chart, but instead of constant efficiency curves there will be curves of constant peak-peak values. This way, it is possible to find an optimal operation point for the same power production, were the pressure pulsations are at its lowest. Six points were chosen for further analysis to instigate the effect of changing the speed by ±50 rpm. The analysis shows best results for operation below BEP when the speed was reduced. The change in speed also introduced the possibility to have other frequencies in the system. It is therefore important avoid runner speeds that can cause resonance in the system.

Management of idiopathic intracranial hypertension with a programmable lumboperitoneal shunt: Early experience.

PubMed

Alkherayf, Fahad; Abou Al-Shaar, Hussam; Awad, Michael

2015-09-01

To evaluate the clinical outcomes and complications rate among idiopathic intracranial hypertension (IIH) patients who underwent lumboperitoneal (LP) shunt insertion with a programmable Strata valve. We retrospectively evaluated patients who underwent LP shunt with a programmable Strata valve insertion at the University of Ottawa Civic Hospital from November 2012 to June 2013. The demographic data, clinical symptoms, opening pressure, pre-operative and post-operative visual fields, neuroimaging, visual acuity, disc status, and complications were recorded and analyzed. Seven female patients with IIH underwent insertion of an LP shunt with a programmable Strata valve. The mean opening pressure was 35.8 cm H2O. The initial valve setting was 1.5, and four patients required post-operative valve pressure adjustment. All patients showed significant improvement in objective visual testing at follow-up as well as less frequent headaches. None of the patients developed intra- or post-operative complications. LP shunts with programmable Strata valve systems are a potential alternative to conventional LP and programmable ventriculoperitoneal shunt systems as well as optic nerve sheath fenestration, due to their potential in avoiding brain injury, lower failure and complication rates, lower intracranial hypotension incidence, and flexibility in adjusting valve pressure settings post-operatively evading under- and overdrainage complications. They should be considered for the management of IIH instead of early design LP systems and VP shunts. A randomized multi-center trial should be conducted to compare the efficacy of these surgical techniques. Copyright © 2015 Elsevier B.V. All rights reserved.

Torsional ultrasonic wave based level measurement system

DOEpatents

Holcomb, David E [Oak Ridge, TN; Kisner, Roger A [Knoxville, TN

2012-07-10

A level measurement system suitable for use in a high temperature and pressure environment to measure the level of coolant fluid within the environment, the system including a volume of coolant fluid located in a coolant region of the high temperature and pressure environment and having a level therein; an ultrasonic waveguide blade that is positioned within the desired coolant region of the high temperature and pressure environment; a magnetostrictive electrical assembly located within the high temperature and pressure environment and configured to operate in the environment and cooperate with the waveguide blade to launch and receive ultrasonic waves; and an external signal processing system located outside of the high temperature and pressure environment and configured for communicating with the electrical assembly located within the high temperature and pressure environment.

Small-volume, ultrahigh-vacuum-compatible high-pressure reaction cell for combined kinetic and in situ IR spectroscopic measurements on planar model catalysts

NASA Astrophysics Data System (ADS)

Zhao, Z.; Diemant, T.; Häring, T.; Rauscher, H.; Behm, R. J.

2005-12-01

We describe the design and performance of a high-pressure reaction cell for simultaneous kinetic and in situ infrared reflection (IR) spectroscopic measurements on model catalysts at elevated pressures, between 10-3 and 103mbars, which can be operated both as batch reactor and as flow reactor with defined gas flow. The cell is attached to an ultrahigh-vacuum (UHV) system, which is used for sample preparation and also contains facilities for sample characterization. Specific for this design is the combination of a small cell volume, which allows kinetic measurements with high sensitivity under batch or continuous flow conditions, the complete isolation of the cell from the UHV part during UHV measurements, continuous temperature control during both UHV and high-pressure operation, and rapid transfer between UHV and high-pressure stage. Gas dosing is performed by a designed gas-handling system, which allows operation as flow reactor with calibrated gas flows at adjustable pressures. To study the kinetics of reactions on the model catalysts, a quadrupole mass spectrometer is connected to the high-pressure cell. IR measurements are possible in situ by polarization-modulation infrared reflection-absorption spectroscopy, which also allows measurements at elevated pressures. The performance of the setup is demonstrated by test measurements on the kinetics for CO oxidation and the CO adsorption on a Au /TiO2/Ru(0001) model catalyst film at 1-50 mbar total pressure.

30 CFR 250.617 - Blowout preventer system testing, records, and drills.

Code of Federal Regulations, 2014 CFR

2014-07-01

... drills. 250.617 Section 250.617 Mineral Resources BUREAU OF SAFETY AND ENVIRONMENTAL ENFORCEMENT... Gas Well-Workover Operations § 250.617 Blowout preventer system testing, records, and drills. (a) BOP... disconnecting a pressure seal in the assembly, the affected seal will be pressure tested. (c) Drills. All...

30 CFR 250.616 - Blowout preventer system testing, records, and drills.

Code of Federal Regulations, 2012 CFR

2012-07-01

... drills. 250.616 Section 250.616 Mineral Resources BUREAU OF SAFETY AND ENVIRONMENTAL ENFORCEMENT... Gas Well-Workover Operations § 250.616 Blowout preventer system testing, records, and drills. (a) BOP... disconnecting a pressure seal in the assembly, the affected seal will be pressure tested. (c) Drills. All...

30 CFR 250.617 - Blowout preventer system testing, records, and drills.

Code of Federal Regulations, 2013 CFR

2013-07-01

... drills. 250.617 Section 250.617 Mineral Resources BUREAU OF SAFETY AND ENVIRONMENTAL ENFORCEMENT... Gas Well-Workover Operations § 250.617 Blowout preventer system testing, records, and drills. (a) BOP... disconnecting a pressure seal in the assembly, the affected seal will be pressure tested. (c) Drills. All...

Flow analysis of airborne particles in a hospital operating room

NASA Astrophysics Data System (ADS)

Faeghi, Shiva; Lennerts, Kunibert

2016-06-01

Preventing airborne infections during a surgery has been always an important issue to deliver effective and high quality medical care to the patient. One of the important sources of infection is particles that are distributed through airborne routes. Factors influencing infection rates caused by airborne particles, among others, are efficient ventilation and the arrangement of surgical facilities inside the operating room. The paper studies the ventilation airflow pattern in an operating room in a hospital located in Tehran, Iran, and seeks to find the efficient configurations with respect to the ventilation system and layout of facilities. This study uses computational fluid dynamics (CFD) and investigates the effects of different inflow velocities for inlets, two pressurization scenarios (equal and excess pressure) and two arrangements of surgical facilities in room while the door is completely open. The results show that system does not perform adequately when the door is open in the operating room under the current conditions, and excess pressure adjustments should be employed to achieve efficient results. The findings of this research can be discussed in the context of design and controlling of the ventilation facilities of operating rooms.

Fast pressure-sensor system

NASA Technical Reports Server (NTRS)

Gross, C.

1976-01-01

Miniature silicon-diaphragm sensors and signal multiplexer are mounted to ganged zero-operate-calibrate pressure selector switches. Device allows in-situ calibration, can be computer controlled, and measures at approximately 10,000 readings per second.

40 CFR Table 3 to Subpart Jjjjjj... - Operating Limits for Boilers With Emission Limits

Code of Federal Regulations, 2011 CFR

2011-07-01

... system alarm does not sound more than 5 percent of the operating time during each 6-month period. 2... the pressure drop at or above the lowest 1-hour average pressure drop across the wet scrubber and the... recent performance stack test. 8. Continuous Oxygen Monitor Maintain the oxygen level at or above the...

Vehicle having hydraulic and power steering systems using a single high pressure pump

DOEpatents

Bartley, Bradley E.; Blass, James R.; Gibson, Dennis H.

2001-06-22

A vehicle comprises a plurality of wheels attached to a vehicle housing. Also attached to the vehicle housing is a power steering system, including a fluid flow circuit, which is operably coupled to a number of the wheels. An internal combustion engine attached to the vehicle housing is connected to a hydraulically actuated system that includes a high pressure pump. An outlet of the high pressure pump is in fluid communication with the fluid flow circuit.

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

NASA Technical Reports Server (NTRS)

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

2003-01-01

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

Assessment of diffuser pressure loss on WWTPs in Baden-Württemberg.

PubMed

Krampe, J

2011-01-01

Aeration of activated sludge is a critical treatment step for the operation of activated sludge plants. To achieve a cost effective treatment process, assessing and benchmarking of aeration system performance are important measures. A simple means of gauging the relative condition of a fine bubble diffused aeration system is to evaluate the pressure loss of the diffusers as oxygen transfer tests are rarely applied during the lifetime of an aeration system. This paper shows an assessment of fine bubble diffuser systems in Baden-Württemberg, Germany, based on the results of a questionnaire sent to 941 WWTPs. Apart from the results with regards to the diffuser pressure loss, this paper also presents information on the current state of diffuser technology such as types and materials as well as the diffuser cleaning methods used in Baden-Württemberg. The majority of the WWTPs were equipped with tube diffusers (71%) with 50% of all plants having EPDM membranes installed. Regular mechanical cleaning is the most common cleaning method followed by regular pressure release/air-bumping programs during operations. With regard to the diffuser pressure loss it was found that 50% of the evaluated plants had a diffuser pressure loss that was twice as high as measured for new diffusers.

Bipropellant propulsion with reciprocating pumps

NASA Astrophysics Data System (ADS)

Whitehead, John C.

1993-06-01

A pressure regulated gas generator rocket cycle with alternately pressurized pairs of reciprocating pumps offers thrust-on-demand operation with significantly lower inert mass than conventional spacecraft liquid propulsion systems. The operation of bipropellant feed systems with reciprocating pumps is explained, with consideration for both short and long term missions. There are several methods for startup and shutdown of this self-starting pump-fed system, with preference determined by thrust duty cycle and mission duration. Progress to date includes extensive development testing of components unique to this type of system, and several live tests with monopropellant hydrazine. Pneumatic pump control valves which render pistons and bellows automatically responsive to downstream liquid demand are significantly simpler than those described previously. A compact pumpset mounted to central liquid manifolds has a pair of oxidizer pumps pneumatically slaved to a pair of fuel pumps to reduce vibration. A warm gas pressure reducer for tank expulsion can eliminate any remaining need for inert gas storage.

Thermodynamic performance testing of the orbiter flash evaporator system

NASA Technical Reports Server (NTRS)

Jaax, J. R.; Melgares, M. A.; Frahm, J. P.

1980-01-01

System level testing of the space shuttle orbiter's development flash evaporator system (FES) was performed in a thermal vacuum chamber capable of simulating ambient ascent, orbital, and entry temperature and pressure profiles. The test article included the evaporator assembly, high load and topping exhaust duct and nozzle assemblies, and feedwater supply assembly. Steady state and transient heat load, water pressure/temperature and ambient pressure/temperature profiles were imposed by especially designed supporting test hardware. Testing in 1978 verified evaporator and duct heater thermal design, determined FES performance boundaries, and assessed topping evaporator plume characteristics. Testing in 1979 combined the FES with the other systems in the orbiter active thermal control subsystem (ATCS). The FES met or exceeded all nominal and contingency performance requirements during operation with the integrated ATCS. During both tests stability problems were encountered during steady state operations which resulted in subsequent design changes to the water spray nozzle and valve plate assemblies.

Advanced spacecraft fuel cell systems

NASA Technical Reports Server (NTRS)

Thaller, L. H.

1972-01-01

The development and characteristics of advanced spacecraft fuel cell systems are discussed. The system is designed to operate on low pressure, propulsion grade hydrogen and oxygen. The specific goals are 10,000 hours of operation with refurbishment, 20 pounds per kilowatt at a sustained power of 7 KW, and 21 KW peaking capability for durations of two hours. The system rejects waste heat to the spacecraft cooling system at power levels up to 7 KW. At higher powers, the system automatically transfers to open cycle operation with overboard steam venting.

Effects of Injection Scheme on Rotating Detonation Engine Operation

NASA Astrophysics Data System (ADS)

Chacon, Fabian; Duvall, James; Gamba, Mirko

2017-11-01

In this work, we experimentally investigate the operation and performance characteristics of a rotating detonation engine (RDE) operated with different fuel injection schemes and operating conditions. In particular, we investigate the detonation and operation characteristics produced with an axial flow injector configuration and semi-impinging injector configurations. These are compared to the characteristics produced with a canonical radial injection system (AFRL injector). Each type produces a different flowfield and mixture distribution, leading to a different detonation initiation, injector dynamic response, and combustor pressure rise. By using a combination of diagnostics, we quantify the pressure loses and gains in the system, the ability to maintain detonation over a range of operating points, and the coupling between the detonation and the air/fuel feed lines. We particularly focus on how this coupling affects both the stability and the performance of the detonation wave. This work is supported by the DOE/UTSR program under project DE-FE0025315.

Operability of an Ejector Enhanced Pulse Combustor in a Gas Turbine Environment

NASA Technical Reports Server (NTRS)

Paxson, Daniel E.; Dougherty, Kevin

2008-01-01

A pressure-gain combustor comprised of a mechanically valved, liquid fueled pulsejet, an ejector, and an enclosing shroud, was coupled to a small automotive turbocharger to form a self-aspirating, thrust producing gas turbine engine. The system was constructed in order to investigate issues associated with the interaction of pulsed combustion devices and turbomachinery. Installed instrumentation allowed for sensing of distributed low frequency pressure and temperature, high frequency pressure in the shroud, fuel flow rate, rotational speed, thrust, and laboratory noise. The engine ran successfully and reliably, achieving a sustained thrust of 5 to 6 lbf, and maintaining a rotor speed of approximately 90,000 rpm, with a combustor pressure gain of approximately 4 percent. Numerical simulations of the system without pressure-gain combustion indicated that the turbocharger would not operate. Thus, the new combustor represented a substantial improvement in system performance. Acoustic measurements in the shroud and laboratory indicated turbine stage sound pressure level attenuation of 20 dB. This is consistent with published results from detonative combustion experiments. As expected, the mechanical reed valves suffered considerable damage under the higher pressure and thermal loading characteristics of this system. This result underscores the need for development of more robust valve systems for this application. The efficiency of the turbomachinery components did not appear to be significantly affected by unsteadiness associated with pulsed combustion, though the steady component efficiencies were already low, and thus not expected to be particularly sensitive.

Solar Thermal Upper Stage Cryogen System Engineering Checkout Test

NASA Technical Reports Server (NTRS)

Olsen, A. D; Cady, E. C.; Jenkins, D. S.

1999-01-01

The Solar Thermal Upper Stage technology (STUSTD) program is a solar thermal propulsion technology program cooperatively sponsored by a Boeing led team and by NASA MSFC. A key element of its technology program is development of a liquid hydrogen (LH2) storage and supply system which employs multi-layer insulation, liquid acquisition devices, active and passive thermodynamic vent systems, and variable 40W tank heaters to reliably provide near constant pressure H2 to a solar thermal engine in the low-gravity of space operation. The LH2 storage and supply system is designed to operate as a passive, pressure fed supply system at a constant pressure of about 45 psia. During operation of the solar thermal engine over a small portion of the orbit the LH2 storage and supply system propulsively vents through the enjoy at a controlled flowrate. During the long coast portion of the orbit, the LH2 tank is locked up (unvented). Thus, all of the vented H2 flow is used in the engine for thrust and none is wastefully vented overboard. The key to managing the tank pressure and therefore the H2 flow to the engine is to manage and balance the energy flow into the LH2 tank with the MLI and tank heaters with the energy flow out of the LH2 tank through the vented H2 flow. A moderate scale (71 cu ft) LH2 storage and supply system was installed and insulated at the NASA MSFC Test Area 300. The operation of the system is described in this paper. The test program for the LH2 system consisted of two parts: 1) a series of engineering tests to characterize the performance of the various components in the system: and 2) a 30-day simulation of a complete LEO and GEO transfer mission. This paper describes the results of the engineering tests, and correlates these results with analytical models used to design future advanced Solar Orbit Transfer Vehicles.

Pressurization, Pneumatic, and Vent Subsystems of the X-34 Main Propulsion System

NASA Technical Reports Server (NTRS)

Hedayat, A.; Steadman, T. E.; Brown, T. M.; Knight, K. C.; White, C. E., Jr.; Champion, R. H., Jr.

1998-01-01

In pressurization systems, regulators and orifices are use to control the flow of the pressurant. For the X-34 Main Propulsion System, three pressurization subsystem design configuration options were considered. In the first option, regulators were used while in the other options, orifices were considered. In each design option, the vent/relief system must be capable of relieving the pressurant flow without allowing the tank pressure to rise above proof, therefore, impacts on the propellant tank vent system were investigated and a trade study of the pressurization system was conducted. The analysis indicated that design option using regulators poses least risk. Then, a detailed transient thermal/fluid analysis of the recommended pressurization system was performed. Helium usage, thermodynamic conditions, and overpressurization of each propellant tank were evaluated. The pneumatic and purge subsystem is used for pneumatic valve actuation, Inter-Propellant Seal purges, Engine Spin Start, and engine purges at the required interface pressures, A transient analysis of the pneumatic and purge subsystem provided helium usage and flow rates to Inter-Propellant Seal and engine interfaces. Fill analysis of the helium bottles of pressurization and pneumatic subsystems during ground operation was performed. The required fill time and the stored

Intermittent operation of ultra-low pressure ultrafiltration for decentralized drinking water treatment.

PubMed

Peter-Varbanets, Maryna; Gujer, Willi; Pronk, Wouter

2012-06-15

River water was treated by ultrafiltration at a relatively low transmembrane pressure (40 mbar). As observed before, flux stabilization occurred after several days of operation although no back-flushing or cross flow was applied. Interruptions in flux were applied by temporary offset of the transmembrane pressure. After restoration of the transmembrane pressure, the initial flux was higher than the stable flux level, and the flux recovery depended on the standstill time. Furthermore, if a short cross flow was applied after standstill, the flux was restored to an even higher level. In all cases, the flux decreased again during operation to reach finally the same stable level as before standstill. In order to evaluate the influence of intermittent operation as practiced for water treatment on a household level, daily interruptions of flux were applied. An optimum of total daily water production rate was obtained at 21 h of operation and 3 h of standstill per day. A model was developed which can describe the impact of intermittent operation on the flux depending on the duration of the standstill and operating periods. This enables the prediction of production capacity of the system operated intermittently. The flux increase during standstill could be explained by a relaxation and expansion of the biofouling layer, while the higher flux after forward-flushing was caused by this layer being partially sloughed off. Household water treatment with the process presented here will generally be operated on a discontinuous basis. The results show that such operation schemes do not compromise the permeability of the system, but actually lead to higher fluxes after standstill. Copyright © 2012 Elsevier Ltd. All rights reserved.

Development of CNG direct injection (CNGDI) clean fuel system for extra power in small engine

NASA Astrophysics Data System (ADS)

Ali, Yusoff; Shamsudeen, Azhari; Abdullah, Shahrir; Mahmood, Wan Mohd Faizal Wan

2012-06-01

A new design of fuel system for CNG engine with direct injection (CNGDI) was developed for a demonstration project. The development of the fuel system was done on the engine with cylinder head modifications, for fuel injector and spark plug openings included in the new cylinder head. The piston was also redesigned for higher compression ratio. The fuel rails and the regulators are also designed for the direct injection system operating at higher pressure about 2.0 MPa. The control of the injection timing for the direct injectors are also controlled by the Electronic Control Unit specially designed for DI by another group project. The injectors are selected after testing with the various injection pressures and spray angles. For the best performance of the high-pressure system, selection is made from the tests on single cylinder research engine (SCRE). The components in the fuel system have to be of higher quality and complied with codes and standards to secure the safety of engine for high-pressure operation. The results of the CNGDI have shown that better power output is produced and better emissions were achieved compared to the aspirated CNG engine.

High Temperature Capacitive Pressure Sensor Employing a SiC Based Ring Oscillator

NASA Technical Reports Server (NTRS)

Meredith, Roger D.; Neudeck, Philip G.; Ponchak, George E.; Beheim, Glenn M.; Scardelletti, Maximilian; Jordan, Jennifer L.; Chen, Liang-Yu; Spry, David J.; Krawowski, Michael J.; Hunter, Gary W.

2011-01-01

In an effort to develop harsh environment electronic and sensor technologies for aircraft engine safety and monitoring, we have used capacitive-based pressure sensors to shift the frequency of a SiC-electronics-based oscillator to produce a pressure-indicating signal that can be readily transmitted, e.g. wirelessly, to a receiver located in a more benign environment. Our efforts target 500 C, a temperature well above normal operating conditions of commercial circuits but within areas of interest in aerospace engines, deep mining applications and for future missions to the Venus atmosphere. This paper reports for the first time a ring oscillator circuit integrated with a capacitive pressure sensor, both operating at 500 C. This demonstration represents a significant step towards a wireless pressure sensor that can operate at 500 C and confirms the viability of 500 C electronic sensor systems.

Approximating Fluid Flow from Ambient to Very Low Pressures: Modeling ISS Experiments that Vent to Vacuum

NASA Technical Reports Server (NTRS)

Minor, Robert

2002-01-01

Two ISS (International Space Station) experiment payloads will vent a volume of gas overboard via either the ISS Vacuum Exhaust System or the Vacuum Resource System. A system of ducts, valves and sensors, under design, will connect the experiments to the ISS systems. The following tasks are required: Create an analysis tool that will verify the rack vacuum system design with respect to design requirements, more specifically approximate pressure at given locations within the vacuum systems; Determine the vent duration required to achieve desired pressure within the experiment modules; Update the analysis as systems and operations definitions mature.

Monitoring Welding-Gas Quality

NASA Technical Reports Server (NTRS)

Huddleston, Kevin L.

1988-01-01

System monitors welding gas to ensure characteristics within predetermined values. Responds to changes that might go unnoticed by human operator and acts quickly to prevent weld defects. Electronic pressure controller employs various amounts of gain, equalization, and compensation to respond to changes in gas-supply pressure. Works in conjuction with pressure/oxygen/moisture monitor.

40 CFR 63.1657 - Monitoring requirements.

Code of Federal Regulations, 2011 CFR

2011-07-01

... pressure drop across each baghouse cell, or across the baghouse if it is not possible to monitor each cell individually, to ensure the pressure drop is within the normal operating range identified in the baghouse... detection system if the furnace primary and/or tapping emissions are ducted to a negative pressure baghouse...

High- and low-pressure pneumotachometers measure respiration rates accurately in adverse environments

NASA Technical Reports Server (NTRS)

Fagot, R. J.; Mc Donald, R. T.; Roman, J. A.

1968-01-01

Respiration-rate transducers in the form of pneumotachometers measure respiration rates of pilots operating high performance research aircraft. In each low pressure or high pressure oxygen system a sensor is placed in series with the pilots oxygen supply line to detect gas flow accompanying respiration.

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...

49 CFR 229.49 - Main reservoir system.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 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...

Stronger at Depth: Jamming Grippers as Deep Sea Sampling Tools.

PubMed

Licht, Stephen; Collins, Everett; Mendes, Manuel Lopes; Baxter, Christopher

2017-12-01

In this work we experimentally demonstrate (a) that the holding strength of universal jamming grippers increases as a function of the jamming pressure to greater than three atmospheres, and (b) that jamming grippers can be operated in the deep sea in ambient pressures exceeding one hundred atmospheres, where such high jamming pressures can be readily achieved. Laboratory experiments in a pressurized, water-filled test cell are used to measure the holding force of a "universal" style jamming gripper as a function of the pressure difference between internal membrane pressure and ambient pressure. Experiments at sea are used to demonstrate that jamming grippers can be installed on, and operated from, remotely operated vehicles at depths in excess of 1200 m. In both experiments, the jamming gripper consists of a latex balloon filled with a mixture of fresh water and ∼200 μm glass beads, which are cheaply available in large quantities as sand blasting media. The use of a liquid, rather than a gas, as the fluid media allows operation of the gripper with a closed-loop fluid system; jamming pressure is controlled with an electrically driven water hydraulic cylinder in the laboratory and with an oil hydraulic-driven large-bore water hydraulic cylinder at sea.

Loss of control air at Browns Ferry Unit One: accident sequence analysis

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

Harrington, R.M.; Hodge, S.A.

1986-04-01

This study describes the predicted response of the Browns Ferry Nuclear Plant to a postulated complete failure of plant control air. The failure of plant control air cascades to include the loss of drywell control air at Units 1 and 2. Nevertheless, this is a benign accident unless compounded by simultaneous failures in the turbine-driven high pressure injection systems. Accident sequence calculations are presented for Loss of Control Air sequences with assumed failure upon demand of the Reactor Core Isolation Cooling (RCIC) and the High Pressure Coolant Injection (HPCI) at Unit 1. Sequences with and without operator action are considered.more » Results show that the operators can prevent core uncovery if they take action to utilize the Control Rod Drive Hydraulic System as a backup high pressure injection system.« less

High Pressure Electrolyzer System Evaluation

NASA Technical Reports Server (NTRS)

Prokopius, Kevin; Coloza, Anthony

2010-01-01

This report documents the continuing efforts to evaluate the operational state of a high pressure PEM based electrolyzer located at the NASA Glenn Research Center. This electrolyzer is a prototype system built by General Electric and refurbished by Hamilton Standard (now named Hamilton Sunstrand). It is capable of producing hydrogen and oxygen at an output pressure of 3000 psi. The electrolyzer has been in storage for a number of years. Evaluation and testing was performed to determine the state of the electrolyzer and provide an estimate of the cost for refurbishment. Pressure testing was performed using nitrogen gas through the oxygen ports to ascertain the status of the internal membranes and seals. It was determined that the integrity of the electrolyzer stack was good as there were no appreciable leaks in the membranes or seals within the stack. In addition to the integrity testing, an itemized list and part cost estimate was produced for the components of the electrolyzer system. An evaluation of the system s present state and an estimate of the cost to bring it back to operational status was also produced.

Recent modifications and calibration of the Langley low-turbulence pressure tunnel

NASA Technical Reports Server (NTRS)

Mcghee, R. J.; Beasley, W. D.; Foster, J. M.

1984-01-01

Modifications to the Langley Low-Turbulence Pressure Tunnel are presented and a calibration of the mean flow parameters in the test section is provided. Also included are the operational capability of the tunnel and typical test results for both single-element and multi-element airfoils. Modifications to the facility consisted of the following: replacement of the original cooling coils and antiturbulence screens and addition of a tunnel-shell heating system, a two dimensional model-support and force-balance system, a sidewall boundary layer control system, a remote-controlled survey apparatus, and a new data acquisition system. A calibration of the mean flow parameters in the test section was conducted over the complete operational range of the tunnel. The calibration included dynamic-pressure measurements, Mach number distributions, flow-angularity measurements, boundary-layer characteristics, and total-pressure profiles. In addition, test-section turbulence measurements made after the tunnel modifications have been included with these calibration data to show a comparison of existing turbulence levels with data obtained for the facility in 1941 with the original screen installation.

Power generation systems and methods

NASA Technical Reports Server (NTRS)

Jones, Jack A. (Inventor); Chao, Yi (Inventor)

2011-01-01

A power generation system includes a plurality of submerged mechanical devices. Each device includes a pump that can be powered, in operation, by mechanical energy to output a pressurized output liquid flow in a conduit. Main output conduits are connected with the device conduits to combine pressurized output flows output from the submerged mechanical devices into a lower number of pressurized flows. These flows are delivered to a location remote of the submerged mechanical devices for power generation.

User manual for NASA Lewis 10 by 10 foot supersonic wind tunnel. Revised

NASA Technical Reports Server (NTRS)

Soeder, Ronald H.

1995-01-01

This manual describes the 10- by 10-Foot Supersonic Wind Tunnel at the NASA Lewis Research Center and provides information for users who wish to conduct experiments in this facility. Tunnel performance operating envelopes of altitude, dynamic pressure, Reynolds number, total pressure, and total temperature as a function of test section Mach number are presented. Operating envelopes are shown for both the aerodynamic (closed) cycle and the propulsion (open) cycle. The tunnel test section Mach number range is 2.0 to 3.5. General support systems, such as air systems, hydraulic system, hydrogen system, fuel system, and Schlieren system, are described. Instrumentation and data processing and acquisition systems are also described. Pretest meeting formats and schedules are outlined. Tunnel user responsibility and personnel safety are also discussed.

Final Engineering Report - Phase I HYCOS (Hydraulic Check Out System)

DTIC Science & Technology

1976-07-30

34 Shock Strut Pressure/Level Concept 37 35 Pressure vs Temperature Variation 40 36 Temperature Compensated Pressure Switch (Concept) 41 37...Temperature Compensated Pressure Switch (NEO-DYNE) ... 42 38 Deslccant Saturation Monitor 43 39 HIAC Model PC-120 Contamination Monitor 44 40...variables. If a thermal compensated pressure switch is utilized which has the same operating slope as the ideal gaa, then a low charge can be

Gas-Liquid Flows and Phase Separation

NASA Technical Reports Server (NTRS)

McQuillen, John

2004-01-01

Common issues for space system designers include:Ability to Verify Performance in Normal Gravity prior to Deployment; System Stability; Phase Accumulation & Shedding; Phase Separation; Flow Distribution through Tees & Manifolds Boiling Crisis; Heat Transfer Coefficient; and Pressure Drop.The report concludes:Guidance similar to "A design that operates in a single phase is less complex than a design that has two-phase flow" is not always true considering the amount of effort spent on pressurizing, subcooling and phase separators to ensure single phase operation. While there is still much to learn about two-phase flow in reduced gravity, we have a good start. Focus now needs to be directed more towards system level problems .

Pressure control and analysis report: Hydrogen Thermal Test Article (HTTA)

NASA Technical Reports Server (NTRS)

1971-01-01

Tasks accomplished during the HTTA Program study period included: (1) performance of a literature review to provide system guidelines; (2) development of analytical procedures needed to predict system performance; (3) design and analysis of the HTTA pressurization system considering (a) future utilization of results in the design of a spacecraft maneuvering system propellant package, (b) ease of control and operation, (c) system safety, and (d) hardware cost; and (4) making conclusions and recommendations for systems design.

A high-temperature wideband pressure transducer

NASA Technical Reports Server (NTRS)

Zuckerwar, A. J.

1975-01-01

Progress in the development of a pressure transducer for measurement of the pressure fluctuations in the high temperature environment of a jet exhaust is reported. A condenser microphone carrier system was adapted to meet the specifications. A theoretical analysis is presented which describes the operation of the condenser microphone in terms of geometry, materials, and other physical properties. The analysis was used as the basis for design of a prototype high temperature microphone. The feasibility of connecting the microphone to a converter over a high temperature cable operating as a half-wavelength transmission line was also examined.

Checkout and Standard Use Procedures for the Mark III Space Suit Assembly

NASA Technical Reports Server (NTRS)

Valish, Dana J.

2012-01-01

The operational pressure range is the range to which the suit can be nominally operated for manned testing. The top end of the nominal operational pressure range is equivalent to 1/2 the proof pressure. Structural pressure is 1.5 times the specified test pressure for any given test. Proof pressure is the maximum unmanned pressure to which the suit was tested by the vendor prior to delivery. The maximum allowable working pressure (MAWP) is 90% of the proof pressure. The pressure systems RVs are set to keep components below their MAWPs. If the suit is pressurized over its MAWP, the suit will be taken out of service and an in-depth inspection/review of the suit will be performed before the suit is put back in service. The procedures outlined in this document should be followed as written. However, the suit test engineer (STE) may make redline changes real-time, provided those changes are recorded in the anomaly section of the test data sheet. If technicians supporting suit build-up, check-out, and/or test execution believe that a procedure can be improved, they should notify their lead. If procedures are incorrect to the point of potentially causing hardware damage or affecting safety, bring the problem to the technician lead and/or STE s attention and stop work until a solution (temporary or permanent) is authorized. Certain steps in the procedure are marked with a DV , for Designated Verifier. The Designated Verifier for this procedure is an Advanced Space Suit Technology Development Laboratory technician, not directly involved in performing the procedural steps, who will verify that the step was performed as stated. The steps to be verified by the DV were selected based on one or more of the following criteria: the step was deemed significant in ensuring the safe performance of the test, the data recorded in the step is of specific interest in monitoring the suit system operation, or the step has a strong influence on the successful completion of test objectives. Prior to all manned test activities, Advanced Suit Test Data Sheet (TDS) Parts A-E shall be completed to verify system and team are ready for test. Advanced Suit TDS Parts F-G shall be completed at the end of the suited activity. Appendix B identifies tha appropriate Mark III suit emergency event procedures.

Process optimization of helium cryo plant operation for SST-1 superconducting magnet system

NASA Astrophysics Data System (ADS)

Panchal, P.; Panchal, R.; Patel, R.; Mahesuriya, G.; Sonara, D.; Srikanth G, L. N.; Garg, A.; Christian, D.; Bairagi, N.; Sharma, R.; Patel, K.; Shah, P.; Nimavat, H.; Purwar, G.; Patel, J.; Tanna, V.; Pradhan, S.

2017-02-01

Several plasma discharge campaigns have been carried out in steady state superconducting tokamak (SST-1). SST-1 has toroidal field (TF) and poloidal field (PF) superconducting magnet system (SCMS). The TF coils system is cooled to 4.5 - 4.8 K at 1.5 - 1.7 bar(a) under two phase flow condition using 1.3 kW helium cryo plant. Experience revealed that the PF coils demand higher pressure heads even at lower temperatures in comparison to TF coils because of its longer hydraulic path lengths. Thermal run away are observed within PF coils because of single common control valve for all PF coils in distribution system having non-uniform lengths. Thus it is routine practice to stop the cooling of PF path and continue only TF cooling at SCMS inlet temperature of ˜ 14 K. In order to achieve uniform cool down, different control logic is adopted to make cryo stable system. In adopted control logic, the SCMS are cooled down to 80 K at constant inlet pressure of 9 bar(a). After authorization of turbine A/B, the SCMS inlet pressure is gradually controlled by refrigeration J-T valve to achieve stable operation window for cryo system. This paper presents process optimization for cryo plant operation for SST-1 SCMS.

Design and performance of vacuum system for high heat flux test facility

NASA Astrophysics Data System (ADS)

Swamy Kidambi, Rajamannar; Mokaria, Prakash; Khirwadkar, Samir; Belsare, Sunil; Khan, M. S.; Patel, Tushar; Krishnan, Deepu S.

2017-04-01

High heat flux test facility (HHFTF) at IPR is used for testing thermal performance of plasma facing materials or components. It consists of various subsystems like vacuum system, high power electron beam system, diagnostic and calibration system, data acquisition and control system and high pressure high temperature water circulation system. Vacuum system consists of large D-shaped chamber, target handling system, pumping systems and support structure. The net volume of vacuum chamber is 5 m3 was maintained at the base pressure of the order of 10-6 mbar for operation of electron gun with minimum beam diameter which is achieved with turbo-molecular pump (TMP) and cryo pump. A variable conductance gate valve is used for maintaining required vacuum in the chamber. Initial pumping of the chamber was carried out by using suitable rotary and root pumps. PXI and PLC based faster real time data acquisition and control system is implemented for performing the various operations like remote operation, online vacuum data measurements, display and status indication of all vacuum equipments. This paper describes in detail the design and implementation of various vacuum system for HHFTF.

Thrust Measurements of an Underexpanded Orifice in the Transitional Regime

NASA Astrophysics Data System (ADS)

Ketsdever, Andrew D.

2003-05-01

The popularity of micropropulsion system development has led to renewed interest in the determination of propulsive properties of orifice flows since micronozzle expansions may suffer high viscous losses at low pressure operation. The mass flow and relative thrust for an under expanded orifice is measured as a function of orifice stagnation pressure from 0.1 to 3.5 Torr. Nitrogen, argon, and helium propellant gases are passed through a 1.0 mm diameter orifice with a wall thickness of 0.015 mm . Near-free molecule, transitional and continuum flow regimes are studied. The relative thrust is determined by a novel thrust stand designed primarily for low operating pressure, micropropulsion systems. It is shown that the thrust indications obtained from the stand are a function of the facility background pressure, and corrections are made to determine the indicated thrust for a zero background pressure with nitrogen as propellant. Highly repeatable (within 1 %) indicated thrust measurements are obtained in the thrust range from 5 to 500 μN.

30 CFR 250.1630 - Safety-system testing and records.

Code of Federal Regulations, 2010 CFR

2010-07-01

... AND GAS AND SULPHUR OPERATIONS IN THE OUTER CONTINENTAL SHELF Sulphur Operations § 250.1630 Safety... components, and the following: (1) Safety relief valves on the natural gas feed system for power plant... source. (2) The following safety devices (excluding electronic pressure transmitters and level sensors...

40 CFR 65.84 - Operating requirements.

Code of Federal Regulations, 2010 CFR

2010-07-01

...) CONSOLIDATED FEDERAL AIR RULE Transfer Racks § 65.84 Operating requirements. (a) Closed vent systems or process piping. An owner or operator of a transfer rack shall operate it in such a manner that emissions are... per square inch). (d) Pressure relief device. The owner or operator of a transfer rack subject to the...

System for pressure letdown of abrasive slurries

DOEpatents

Kasper, Stanley

1991-01-01

A system and method for releasing erosive slurries from containment at high pressure without subjecting valves to highly erosive slurry flow. The system includes a pressure letdown tank disposed below the high-pressure tank, the two tanks being connected by a valved line communicating the gas phases and a line having a valve and choke for a transfer of liquid into the letdown tank. The letdown tank has a valved gas vent and a valved outlet line for release of liquid. In operation, the gas transfer line is opened to equalize pressure between tanks so that a low level of liquid flow occurs. The letdown tank is then vented, creating a high-pressure differential between the tanks. At this point, flow between tanks is controlled by the choke. High-velocity, erosive flow through a high-pressure outlet valve is prevented by equalizing the start up pressure and thereafter limiting flow with the choke.

Simulation Analysis of Computer-Controlled pressurization for Mixture Ratio Control

NASA Technical Reports Server (NTRS)

Alexander, Leslie A.; Bishop-Behel, Karen; Benfield, Michael P. J.; Kelley, Anthony; Woodcock, Gordon R.

2005-01-01

A procedural code (C++) simulation was developed to investigate potentials for mixture ratio control of pressure-fed spacecraft rocket propulsion systems by measuring propellant flows, tank liquid quantities, or both, and using feedback from these measurements to adjust propellant tank pressures to set the correct operating mixture ratio for minimum propellant residuals. The pressurization system eliminated mechanical regulators in favor of a computer-controlled, servo- driven throttling valve. We found that a quasi-steady state simulation (pressure and flow transients in the pressurization systems resulting from changes in flow control valve position are ignored) is adequate for this purpose. Monte-Carlo methods are used to obtain simulated statistics on propellant depletion. Mixture ratio control algorithms based on proportional-integral-differential (PID) controller methods were developed. These algorithms actually set target tank pressures; the tank pressures are controlled by another PID controller. Simulation indicates this approach can provide reductions in residual propellants.

Demand thrust pumped propulsion with automatic warm gas valving

NASA Astrophysics Data System (ADS)

Whitehead, J. C.

1992-06-01

Operation of a thrust-on-demand, monopropellant rocket propulsion system which uses lightweight low-pressure tankage, free-piston pumps, and a small high-pressure thrust chamber, is explained. The pump intake-exhaust valves use warm gas pneumatic signals to ensure that two reciprocating pumps are alternately pressurized, with overlap during switchover to permit uninterrupted propellant flow. Experiments demonstrate that the miniature pumps operate at any speed depending on downstream demand, and can deliver nearly their own mass in hydrazine per second, at 7 MPa (1000 psi). The valves, which use the alternating layers of metal and graphite to mitigate the effects of differential thermal expansion, have been warm-gas tested for thousands of cycles. For biopropellant operation, a pair of reciprocating oxidizer pumps would be slaved to the fuel pumps' pneumatic oscillator, to provide for pulsed or continuous demand-driven flow of both liquids. Mass ratios and thrust-to-weight ratios of demand-thrust pumped propulsion systems compare quite favorably to those of pressure-fed and turbo-pumped systems. Due to the relatively high densities of storable propellants, liquid mass fractions greater than 0.95 are attainable with these novel pumps, with thrust/weight ratios above 10. The high performance potential of small propulsion systems which use reciprocating pumps suggests that this technology can significantly increase the capability of many types of small spacecraft.

Pressure and temperature fluctuation simulation of J-PARC cryogenic hydrogen system

NASA Astrophysics Data System (ADS)

Tatsumoto, H.; Ohtsu, K.; Aso, T.; Kawakami, Y.

2015-12-01

The J-PARC cryogenic hydrogen system provides supercritical cryogenic hydrogen to the moderators at a pressure of 1.5 MPa and temperature of 18 K and removes 3.8 kW of nuclear heat from the 1 MW proton beam operation. We prepared a heater for thermal compensation and an accumulator, with a bellows structure for volume control, to mitigate the pressure fluctuation caused by switching the proton beam on and off. In this study, a 1-D simulation code named DiSC-SH2 was developed to understand the propagation of pressure and temperature propagations through the hydrogen loop due to on and off switching of the proton beam. We confirmed that the simulated dynamic behaviors in the hydrogen loop for 300-kW and 500-kW proton beam operations agree well with the experimental data under the same conditions.

Gasometer: An inexpensive device for continuous monitoring of dissolved gases and supersaturation

USGS Publications Warehouse

Bouck, G.R.

1982-01-01

The “gasometer” is a device that measures differential dissolved-gas pressures (δP) in water relative to barometric pressure (as does the “Weiss saturometer”), but operates continuously without human attention. The gasometer can be plumbed into a water-supply system and requires 8 liters/minute of water or more at 60 kilopascals. The gasometer's surfaces are nontoxic, and flow-through water can be used for fish culture. The gasometer may be connected to a small submersible pump and operated as a portable unit. The gasometer can activate an alarm system and thus protect fish from hyperbaric (supersaturation) or hypobaric gas pressures (usually due to low dissolved oxygen). Instructions are included for calculating and reporting data including the pressure and saturation of individual gases. Construction and performance standards are given for the gasometer. Occasional cleaning is required to remove biofouling from the gas-permeable tubing.PDF

Performance Study of Salt Cavern Air Storage Based Non-Supplementary Fired Compressed Air Energy Storage System

NASA Astrophysics Data System (ADS)

Chen, Xiaotao; Song, Jie; Liang, Lixiao; Si, Yang; Wang, Le; Xue, Xiaodai

2017-10-01

Large-scale energy storage system (ESS) plays an important role in the planning and operation of smart grid and energy internet. Compressed air energy storage (CAES) is one of promising large-scale energy storage techniques. However, the high cost of the storage of compressed air and the low capacity remain to be solved. This paper proposes a novel non-supplementary fired compressed air energy storage system (NSF-CAES) based on salt cavern air storage to address the issues of air storage and the efficiency of CAES. Operating mechanisms of the proposed NSF-CAES are analysed based on thermodynamics principle. Key factors which has impact on the system storage efficiency are thoroughly explored. The energy storage efficiency of the proposed NSF-CAES system can be improved by reducing the maximum working pressure of the salt cavern and improving inlet air pressure of the turbine. Simulation results show that the electric-to-electric conversion efficiency of the proposed NSF-CAES can reach 63.29% with a maximum salt cavern working pressure of 9.5 MPa and 9 MPa inlet air pressure of the turbine, which is higher than the current commercial CAES plants.

System for controlling the flow of gas into and out of a gas laser

DOEpatents

Alger, Terry; Uhlich, Dennis M.; Benett, William J.; Ault, Earl R.

1994-01-01

A modularized system for controlling the gas pressure within a copper vapor or like laser is described herein. This system includes a gas input assembly which serves to direct gas into the laser in a controlled manner in response to the pressure therein for maintaining the laser pressure at a particular value, for example 40 torr. The system also includes a gas output assembly including a vacuum pump and a capillary tube arrangement which operates within both a viscous flow region and a molecular flow region for drawing gas out of the laser in a controlled manner.

Electronic scanning pressure measuring system and transducer package

NASA Technical Reports Server (NTRS)

Coe, C. F. (Inventor); Parra, G. T.

1984-01-01

An electronic scanning pressure system that includes a plurality of pressure transducers is examined. A means obtains an electrical signal indicative of a pressure measurement from each of the plurality of pressure transducers. A multiplexing means is connected for selectivity supplying inputs from the plurality of pressure transducers to the signal obtaining means. A data bus connects the plurality of pressure transducers to the multiplexing means. A latch circuit is connected to supply control inputs to the multiplexing means. An address bus is connected to supply an address signal of a selected one of the plurality of pressure transducers to the latch circuit. In operation, each of the pressure transducers is successively scanned by the multiplexing means in response to address signals supplied on the address bus to the latch circuit.

Design and development of the Waukesha Custom Engine Control Air/Fuel Module

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

Moss, D.W.

1996-12-31

The Waukesha Custom Engine Control Air/Fuel Module (AFM) is designed to control the air-fuel ratio for all Waukesha carbureted, gaseous fueled, industrial engine. The AFM is programmed with a personal computer to run in one of four control modes: catalyst, best power, best economy, or lean-burn. One system can control naturally aspirated, turbocharged, in-line or vee engines. The basic system consists of an oxygen sensing system, intake manifold pressure transducer, electronic control module, actuator and exhaust thermocouple. The system permits correct operation of Waukesha engines in spite of changes in fuel pressure or temperature, engine load or speed, and fuelmore » composition. The system utilizes closed loop control and is centered about oxygen sensing technology. An innovative approach to applying oxygen sensors to industrial engines provides very good performance, greatly prolongs sensor life, and maintains sensor accuracy. Design considerations and operating results are given for application of the system to stationary, industrial engines operating on fuel gases of greatly varying composition.« less

40 CFR 60.274 - Monitoring of operations.

Code of Federal Regulations, 2010 CFR

2010-07-01

... that is important to the performance of the total capture system (i.e., pressure sensors, dampers, and... under paragraph (d) of this section; and (4) All pressure data obtained under paragraph (f) of this... provisions of this subpart shall check and record on a once-per-shift basis furnace static pressure (if a DEC...

40 CFR 62.14460 - What records must I maintain?

Code of Federal Regulations, 2010 CFR

2010-07-01

... recorded during each minute of operation; (8) Liquor flow rate to the wet scrubber inlet during each minute of operation, as applicable, (9) Horsepower or amperage to the wet scrubber during each minute of operation, as applicable; (10) Pressure drop across the wet scrubber system during each minute of operation...

40 CFR 62.14460 - What records must I maintain?

Code of Federal Regulations, 2011 CFR

2011-07-01

... recorded during each minute of operation; (8) Liquor flow rate to the wet scrubber inlet during each minute of operation, as applicable, (9) Horsepower or amperage to the wet scrubber during each minute of operation, as applicable; (10) Pressure drop across the wet scrubber system during each minute of operation...

OBSAPS Data Acquisition System: Operator’s Manual and System Overview

DTIC Science & Technology

2011-05-01

Explanation of Druck Voltage to Depth Conversion used during OBSAPS (April-May’11)   25   Druck  Pressure  sensor  conversion  from...for H-91, PA Voltage, PA Current and Sonobuoy and Druck pressure sensor analog inputs. 6. Software settable thresholds for H-91, PA Voltage, PA...17. Custom dry side box for Druck Pressure Sensor supply voltage and dropping resistor. 18. Battery 9-30VDC for supplying Druck power 19. Druck PTX

[Program for lowering the incidence of pressure sores in neurosurgical patients].

PubMed

Chang, Chau-Hui; Chen, Hui-Ling; Chen, Hsiang-Chi

2007-12-01

Pressure sores are one of the well known problems that occur in hospitals. As the literature on the subject indicates, a lot of money is expended in managing this problem every year, and 12-66% of pressure sores are caused during surgery. Patients who undergo neurosurgical procedures are susceptible to pressure sores because of lengthy operations. We collected data on patients with pressure sores who underwent surgery between May 2004 and August 2004, and found that the incidence of pressure sore in neurosurgical patients was 9.5%, which was the highest among all surgical patients. This project was developed to solve the problem of pressure sores by setting up standard preventive procedures, a nursing follow up system and continuing education courses, and utilizing cotton rolls to pad sites of pressure sores. The incidence of pressure sore in neurosurgical patients was reduced from 9.5% to 7% after the improvement project was carried out. The more concerned nurses are about pressure sores, the better the quality of operative nursing care.

Monodisperse alginate microgel formation in a three-dimensional microfluidic droplet generator.

PubMed

Lian, Meng; Collier, C Patrick; Doktycz, Mitchel J; Retterer, Scott T

2012-01-01

Droplet based microfluidic systems provide an ideal platform for partitioning and manipulating aqueous samples for analysis. Identifying stable operating conditions under which droplets are generated is challenging yet crucial for real-world applications. A novel three-dimensional microfluidic platform that facilitates the consistent generation and gelation of alginate-calcium hydrogel microbeads for microbial encapsulation, over a broad range of input pressures, in the absence of surfactants is described. The unique three-dimensional design of the fluidic network utilizes a height difference at the junction between the aqueous sample injection and organic carrier channels to induce droplet formation via a surface tension enhanced self-shearing mechanism. Combined within a flow-focusing geometry, under constant pressure control, this arrangement facilitates predictable generation of droplets over a much broader range of operating conditions than that of conventional two-dimensional systems. The impact of operating pressures and geometry on droplet gelation, aqueous and organic material flow rates, microbead size, and bead generation frequency are described. The system presented provides a robust platform for encapsulating single microbes in complex mixtures into individual hydrogel beads, and provides the foundation for the development of a complete system for sorting and analyzing microbes at the single cell level.

Monodisperse alginate microgel formation in a three-dimensional microfluidic droplet generator

PubMed Central

Lian, Meng; Collier, C. Patrick; Doktycz, Mitchel J.; Retterer, Scott T.

2012-01-01

Droplet based microfluidic systems provide an ideal platform for partitioning and manipulating aqueous samples for analysis. Identifying stable operating conditions under which droplets are generated is challenging yet crucial for real-world applications. A novel three-dimensional microfluidic platform that facilitates the consistent generation and gelation of alginate-calcium hydrogel microbeads for microbial encapsulation, over a broad range of input pressures, in the absence of surfactants is described. The unique three-dimensional design of the fluidic network utilizes a height difference at the junction between the aqueous sample injection and organic carrier channels to induce droplet formation via a surface tension enhanced self-shearing mechanism. Combined within a flow-focusing geometry, under constant pressure control, this arrangement facilitates predictable generation of droplets over a much broader range of operating conditions than that of conventional two-dimensional systems. The impact of operating pressures and geometry on droplet gelation, aqueous and organic material flow rates, microbead size, and bead generation frequency are described. The system presented provides a robust platform for encapsulating single microbes in complex mixtures into individual hydrogel beads, and provides the foundation for the development of a complete system for sorting and analyzing microbes at the single cell level. PMID:24198865

The Design and Operation of a Slowfall AXCP (Air-Deployed Expendable Current Profiler).

DTIC Science & Technology

1988-05-01

Control Sensors pressure switch , P/N 607G6 .................................................... 13 Figure 8. Two-dimensional, free-body diagram of the...surface as well as a release mechanism. We then considered using an inexpensive pressure switch to trip the release mechanism. After a market survey...guillotine and pressure switch from the 250 to 300 psi pressure of seawater without resorting to a high precision 0-ring sealing system and pressure

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

NASA Technical Reports Server (NTRS)

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

2006-01-01

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

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.

46 CFR 38.05-3 - Design and construction of pressure vessel type cargo tanks-TB/ALL.

Code of Federal Regulations, 2010 CFR

2010-10-01

... will, by themselves, constitute the cargo containment system and usually will not require a secondary... tanks by their support due to static and dynamic forces under operating conditions or during testing... percent of the vapor pressure corresponding to the temperature of the liquid at which the system is...

40 CFR 63.7113 - What are my monitoring installation, operation, and maintenance requirements?

Code of Federal Regulations, 2010 CFR

2010-07-01

... continuity, and all mechanical connections for leakage. (d) For each bag leak detection system (BLDS), you... mechanical connections for leakage. (c) For each pressure measurement device, you must meet the requirements... instrumentation and alarm. (6) Bag leak detection systems must be installed, operated, adjusted, and maintained...

14 CFR 31.49 - Control systems.

Code of Federal Regulations, 2014 CFR

2014-01-01

.... (c) Each balloon using a captive gas as the lifting means must have an automatic valve or appendix... STANDARDS: MANNED FREE BALLOONS Design Construction § 31.49 Control systems. (a) Each control must operate... minute when the balloon is at its maximum operating pressure. (d) Each hot air balloon must have a means...

14 CFR 31.49 - Control systems.

Code of Federal Regulations, 2013 CFR

2013-01-01

.... (c) Each balloon using a captive gas as the lifting means must have an automatic valve or appendix... STANDARDS: MANNED FREE BALLOONS Design Construction § 31.49 Control systems. (a) Each control must operate... minute when the balloon is at its maximum operating pressure. (d) Each hot air balloon must have a means...

14 CFR 31.49 - Control systems.

Code of Federal Regulations, 2011 CFR

2011-01-01

.... (c) Each balloon using a captive gas as the lifting means must have an automatic valve or appendix... STANDARDS: MANNED FREE BALLOONS Design Construction § 31.49 Control systems. (a) Each control must operate... minute when the balloon is at its maximum operating pressure. (d) Each hot air balloon must have a means...

14 CFR 31.49 - Control systems.

Code of Federal Regulations, 2012 CFR

2012-01-01

.... (c) Each balloon using a captive gas as the lifting means must have an automatic valve or appendix... STANDARDS: MANNED FREE BALLOONS Design Construction § 31.49 Control systems. (a) Each control must operate... minute when the balloon is at its maximum operating pressure. (d) Each hot air balloon must have a means...

Pneumatic binary encoder replaces multiple solenoid system

NASA Technical Reports Server (NTRS)

1966-01-01

Pneumatic binary encoder replaces solenoid system in the pilot stage of a digital actuator. The encoder operates in flip-flop manner to valve gas at either high or low pressures. By rotating the disk in a pinion-to-encoding gear ratio, six to eight adder circuits may be operated from single encoder.

Hypothesis: the regulation of the partial pressure of oxygen by the serotonergic nervous system in hypoxia.

PubMed

Devereux, Diana; Ikomi-Kumm, Julie

2013-03-01

The regulation of the partial pressure of oxygen by the serotonergic nervous system in hypoxia is a hypothesis, which proposes an inherent operative system in homo sapiens that allows central nervous system and endocrine-mediated vascular system adaption to variables in partial pressure of oxygen, pH and body composition, while maintaining sufficient oxygen saturation for the immune system and ensuring protection of major organs in hypoxic and suboptimal conditions. While acknowledging the importance of the Henderson-Hasselbalch equation in the regulation of acid base balance, the hypothesis seeks to define the specific neuroendocrine/vascular mechanisms at work in regulating acid base balance in hypoxia and infection. The SIA (serotonin-immune-adrenergic) system is proposed as a working model, which allows central nervous system and endocrine-mediated macro- and micro vascular 'fine tuning'. The neurotransmitter serotonin serves as a 'hypoxic sensor' in concert with other operators to orchestrate homeostatic balance in normal and pathological states. The SIA system finely regulates oxygen, fuel and metabolic buffering systems at local sites to ensure optimum conditions for the immune response. The SIA system is fragile and its operation may be affected by infection, stress, diet, environmental toxins and lack of exercise. The hypothesis provides new insight in the area of neuro-gastroenterology, and emphasizes the importance of diet and nutrition as a complement in the treatment of infection, as well as the normalization of intestinal flora following antibiotic therapy. Copyright © 2012 Elsevier Ltd. All rights reserved.

A compact nanopower low output impedance CMOS operational amplifier for wireless intraocular pressure recordings.

PubMed

Dresher, Russell P; Irazoqui, Pedro P

2007-01-01

Wireless sensing has shown potential benefits for the continuous-time measurement of physiological data. One such application is the recording of intraocular pressure (IOP) for patients with glaucoma. Ultra-low-power circuits facilitate the use of inductively-coupled power for implantable wireless systems. Compact circuit size is also desirable for implantable systems. As a first step towards the realization of such circuits, we have designed a compact, ultra-low-power operational amplifier which can be used to record IOP. This paper presents the measured results of a CMOS operational amplifier that can be incorporated with a wireless IOP monitoring system or other low-power application. It has a power consumption of 736 nW, chip area of 0.023 mm2, and output impedance of 69 Omega to drive low-impedance loads.

Method for automatically scramming a nuclear reactor

DOEpatents

Ougouag, Abderrafi M.; Schultz, Richard R.; Terry, William K.

2005-12-27

An automatically scramming nuclear reactor system. One embodiment comprises a core having a coolant inlet end and a coolant outlet end. A cooling system operatively associated with the core provides coolant to the coolant inlet end and removes heated coolant from the coolant outlet end, thus maintaining a pressure differential therebetween during a normal operating condition of the nuclear reactor system. A guide tube is positioned within the core with a first end of the guide tube in fluid communication with the coolant inlet end of the core, and a second end of the guide tube in fluid communication with the coolant outlet end of the core. A control element is positioned within the guide tube and is movable therein between upper and lower positions, and automatically falls under the action of gravity to the lower position when the pressure differential drops below a safe pressure differential.

Blade pressure measurements

NASA Astrophysics Data System (ADS)

Chivers, J. W. H.

Three measurement techniques which enable rotating pressures to be measured during the normal operation of a gas turbine or a component test rig are described. The first technique was developed specifically to provide steady and transient blade surface pressure data to aid both fan flutter research and general fan performance development. This technique involves the insertion of miniature high frequency response pressure transducers into the fan blades of a large civil gas turbine. The other two techniques were developed to measure steady rotating pressures inside and on the surface of engine or rig turbine blades and also rotating pressures in cooling feed systems. These two low frequency response systems are known as the "pressure pineapple' (a name which resulted from the shape of the original prototype) and the rotating scanivalve.

A wall interference assessment/correction interface measurement system for the NASA/ARC 12-ft PWT

NASA Technical Reports Server (NTRS)

1989-01-01

Development of complex air vehicle configurations is placing increasing demands on wind tunnel testing capabilities. A major area of concern is wall induced interference. Recent developments in wall interference technology provide a means for assessing and correcting for the wall induced interference using information contained in the distribution of flow variables measured at, or near, the wall. The restoration of the NASA-ARC 12-ft pressure wind tunnel (PWT) provides an opportunity to incorporate a measurement system with which wall interference assessment/correction (WIAC) technology can be applied. In this first phase of the development of a WIAC system for the PWT, the design criteria for the placement and the geometry of wall static pressure orifices were determined with a three step approach. First, the operational environment of the PWT was analyzed as to the requirements for the WIAC system. Second, appropriate wall interference theories were evaluated against the requirements determined from the operational environment. Third, the flow about representative models in the PWT was calculated and, specifically, the pressure signatures at the location of the test section wall were obtained. The number of discrete pressure measurements and their locations were determined by curve fitting the pressure distribution through the discrete measurements and evaluating the resulting error.

Using CONFIG for Simulation of Operation of Water Recovery Subsystems for Advanced Control Software Evaluation

NASA Technical Reports Server (NTRS)

Malin, Jane T.; Flores, Luis; Fleming, Land; Throop, Daiv

2002-01-01

A hybrid discrete/continuous simulation tool, CONFIG, has been developed to support evaluation of the operability life support systems. CON FIG simulates operations scenarios in which flows and pressures change continuously while system reconfigurations occur as discrete events. In simulations, intelligent control software can interact dynamically with hardware system models. CONFIG simulations have been used to evaluate control software and intelligent agents for automating life support systems operations. A CON FIG model of an advanced biological water recovery system has been developed to interact with intelligent control software that is being used in a water system test at NASA Johnson Space Center

Thermodynamic Vent System Test in a Low Earth Orbit Simulation

NASA Technical Reports Server (NTRS)

VanOverbeke, Thomas J.

2004-01-01

A thermodynamic vent system for a cryogenic nitrogen tank was tested in a vacuum chamber simulating oxygen storage in low earth orbit. The nitrogen tank was surrounded by a cryo-shroud at -40 F. The tank was insulated with two layers of multi-layer insulation. Heat transfer into cryogenic tanks causes phase change and increases tank pressure which must be controlled. A thermodynamic vent system was used to control pressure as the location of vapor is unknown in low gravity and direct venting would be wasteful. The thermodynamic vent system consists of a Joule-Thomson valve and heat exchanger installed on the inlet side of the tank mixer-pump. The combination is used to extract thermal energy from the tank fluid, reducing temperature and ullage pressure. The system was sized so that the tank mixer-pump operated a small fraction of the time to limit motor heating. Initially the mixer used sub-cooled liquid to cool the liquid-vapor interface inducing condensation and pressure reduction. Later, the thermodynamic vent system was used. Pressure cycles were performed until steady-state operation was demonstrated. Three test runs were conducted at tank fills of 97, 80, and 63 percent. Each test was begun with a boil-off test to determine heat transfer into the tank. The lower tank fills had time averaged vent rates very close to steady-state boil-off rates showing the thermodynamic vent system was nearly as efficient as direct venting in normal gravity.

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

PubMed

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

2016-11-18

The limits in operating pressures are extended for narrow-bore columns in gradient elution up to 2000bar. As the required pumps for these pressures are incompatible with common chromatographic solvents and are not suitable to apply a mobile phase composition gradient, a mobile phase delivery and injection system is described and experimentally validated which allows to use any possible chromatographic solvent in isocratic and gradient elution. The mobile phase delivery and injection system also allows to perform multiple separations without the need to depressurize the column. This system consists out of 5 dual on/off valves and two large volume loops in which the gradient and equilibration volume of initial mobile phase are loaded by a commercial liquid chromatography pump. The loops are then flushed toward the column at extreme pressures. The mobile phase delivery and injection system is first evaluated in isocratic elution and shows a comparable performance to a state-of-the-art commercial flow-through-needle injector but with twice the pressure rating. Distortion of the loaded gradient by dispersion in the gradient storage loop is studied. The effect of the most important parameters (such as flow rate, pressure and gradient steepness) is experimentally investigated. Different gradient steepnesses and volumes can be applied at different flow rates and operating pressures with a good repeatability. Due to the isobaric operation of the pumps, the gradient is monitored in real-time by a mass flow meter installed at the detector outlet. The chromatograms are then converted from time to volume-base. A separation of a 19-compound sample is performed on a 300×2.1mm column at 1000bar and on a 600×2.1mm column at 2000bar. The peak capacity was found to increase from 141 to 199 and thus scales with L as is predicted by theory. This allows to conclude that the inlet pressure for narrow-bore columns in gradient elution can be increased up to 2000bar without fundamental pressure-induced limitations. Copyright © 2016 Elsevier B.V. All rights reserved.

Subsea approach to work systems development

NASA Technical Reports Server (NTRS)

Gernhardt, M. L.; Frisbie, F. R.; Brown, C. E.

1988-01-01

Self-contained undersea working environments with applications to space station EVA environments are discussed. Physiological limitations include decompression, inert gas narcosis, high-pressure nervous system, gas toxicity, and thermal limitations. Work task requirements include drilling support, construction, inspection, and repair. Work systems include hyperbaric diving, atmospheric work systems, tele-operated work systems, and hybrid systems. Each type of work system is outlined in terms of work capabilities, special interface requirements, and limitations. Various operational philosophies are discussed. The evolution of work systems in the subsea industry has been the result of direct operational experience in a competitive market.

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.

Optical fiber pressure sensors for adaptive wings

NASA Astrophysics Data System (ADS)

Duncan, Paul G.; Jones, Mark E.; Shinpaugh, Kevin A.; Poland, Stephen H.; Murphy, Kent A.; Claus, Richard O.

1997-06-01

Optical fiber pressure sensors have been developed for use on a structurally-adaptive `smart wing'; further details of the design, fabrication and testing of the smart wing concept are presented in companion papers. This paper describes the design, construction, and performance of the pressure sensor and a combined optical and electronic signal processing system implemented to permit the measurement of a large number of sensors distributed over the control surfaces of a wing. Optical fiber pressure sensors were implemented due to anticipated large electromagnetic interference signals within the operational environment. The sensors utilized the principle of the extrinsic Fabry-Perot interferometer (EFPI) already developed for the measurement of strain and temperature. Here, the cavity is created inside a micromachined hollow-core tube with a silicon diaphragm at one end. The operation of the sensor is similar to that of the EFPI strain gage also discussed in several papers at this conference. The limitations placed upon the performance of the digital signal processing system were determined by the required pressure range of the sensors and the cycle time of the control system used to adaptively modify the shape of the wing. Sensor calibration and the results of testing performed are detailed.

A study on flow development in an APU-style inlet and its effect on centrifugal compressor performance

NASA Astrophysics Data System (ADS)

Lou, Fangyuan

The objectives of this research were to investigate the flow development inside an APU-style inlet and its effect on centrifugal compressor performance. The motivation arises from the increased applications of gas turbine engines installed with APU-style inlets such as unmanned aerial vehicles, auxiliary power units, and helicopters. The inlet swirl distortion created from these complicated inlet systems has become a major performance and operability concern. To improve the integration between the APU-style inlet and gas turbine engines, better understanding of the flow field in the APU-style inlet and its effect on gas turbine is necessary. A research facility for the purpose of performing an experimental investigation of the flow field inside an APU-style inlet was developed. A subcritical air ejector is used to continuously flow the inlet at desired corrected mass flow rates. The facility is capable of flowing the APU inlet over a wide range of corrected mass flow rate that matches the same Mach numbers as engine operating conditions. Additionally, improvement in the system operational steadiness was achieved by tuning the pressure controller using a PID control method and utilizing multi-layer screens downstream of the APU inlet. Less than 1% relative unsteadiness was achieved for full range operation. The flow field inside the rectangular-sectioned 90? bend of the APU-style inlet was measured using a 3-Component LDV system. The structures for both primary flow and the secondary flow inside the bend were resolved. Additionally, the effect of upstream geometry on the flow development in the downstream bend was also investigated. Furthermore, a Single Stage Centrifugal Compressor research facility was developed at Purdue University in collaboration with Honeywell to operate the APU-style inlet at engine conditions with a compressor. To operate the facility, extensive infrastructure for facility health monitoring and performance control (including lubrication systems, secondary air systems, a throttle system, and different inlet configurations) were built. Additionally, three Labview programs were developed for acquiring the compressor health monitoring, steady and unsteady pressure and strain data. The baseline, steady aerodynamic performance map was established. Additionally, the unsteady pressure field in the compressor was investigated. Steady performance data have been acquired from choke to near surge at three different corrected speeds from 90% to 100% corrected speed in 5% increments. The performance of the compressor stage was characterized using total pressure ratio (TPR), total temperature ratio (TTR), and isentropic efficiency. The impeller alone and diffuser along performance were also investigated, and the high loss regions in the compressor were identified. At last, the compressor unsteady shroud pressure was investigated at 100% corrected speed in both the time domain and frequency domain. Results show strong pressure components in relation to the shaft frequency (SF). The impeller has 17 main blades and 17 splitter blades, and introduces pressure fluctuations at 17SF and its harmonics. Additionally, the diffuser has a vane count of 25 and results in pressure spectra of 59SF (17+17+25) due to the interactions between the impeller and diffuser.

Steam dispatching control system demonstration at Fort Benjamin Harrison. Final technical report

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

Diks, C.L.; Moshage, R.E.; Lin, M.C.

1993-07-01

Currently most Army Central steam heating systems operate by maintaining a constant steam pressure regardless of actual steam demand. This method offers some operational convenience, but is often the cause of significant energy losses. Researchers at the U.S. Army Construction Engineering Research Laboratories (USACERL) have investigated the Steam Dispatching Control System (SDCS), a control system that lowers supply steam pressure-and therefore steam temperature-to slightly above the amount needed to meet the steam demand. The lower Steam temperature and reduction in steam loss (from leaks and faulty traps) result in lower heat losses and higher energy savings. Limiting steam pressure canmore » diminish the amount of excess heat loss in the distribution system while still meeting the demand. The Army's Facilities Engineering Applications Program (FEAP) chose Fort Benjamin Harrison, IN, as the Army demonstration site for SDCS. Researchers found that use of SDCS is technically and economically viable improvement over current operating procedures. Analysis based on demonstration results show that the simple payback for SDCS is less than 1 year. The results of this demonstration are generally applicable to installations with a large central heating plant and a substantial steam distribution system. Findings, indicate that energy savings form SDCS are significant regardless of what type of fuel powers the boiler. The authors note that, during the initial evaluation of a potential SDCS application, attention must be paid to the condensate return to ensure that it will operate properly. Fort Benjamin Harrison, IN, Steam Dispatching Control System(SDCS), Central heating plants, energy conservation.« less

Operating Characteristics of the Multiple Critical Venturi System and Secondary Calibration Nozzles Used for Weight-Flow Measurements in the Langley 16-Foot Transonic Tunnel

NASA Technical Reports Server (NTRS)

Berrier, B. L.; Leavitt, L. D.; Bangert, L. S.

1985-01-01

An investigation has been conducted in the Langley 16 Foot Transonic Tunnel to determine the weight flow measurement characteristics of a multiple critical Venturi system and the nozzle discharge coefficient characteristics of a series of convergent calibration nozzles. The effects on model discharge coefficient of nozzle throat area, model choke plate open area, nozzle pressure ratio, jet total temperature, and number and combination of operating Venturis were investigated. Tests were conducted at static conditions (tunnel wind off) at nozzle pressure ratios from 1.3 to 7.0.

New Compressor Added to Glenn's 450- psig Combustion Air System

NASA Technical Reports Server (NTRS)

Swan, Jeffrey A.

2000-01-01

In September 1999, the Central Process Systems Engineering Branch and the Maintenance and the Central Process Systems Operations Branch, released for service a new high pressure compressor to supplement the 450-psig Combustion Air System at the NASA Glenn Research Center at Lewis Field. The new compressor, designated C-18, is located in Glenn s Central Air Equipment Building and is remotely operated from the Central Control Building. C-18 can provide 40 pounds per second (pps) of airflow at pressure to our research customers. This capability augments our existing system capacity (compressors C 4 at 38 pps and C-5 at 32 pps), which is generated from Glenn's Engine Research Building. The C-18 compressor was originally part of Glenn's 21-Inch Hypersonic Tunnel, which was transferred from the Jet Propulsion Laboratory to Glenn in the mid-1980's. With the investment of construction of facilities funding, the compressor was modified, new mechanical and electrical support equipment were purchased, and the unit was installed in the basement of the Central Air Equipment Building. After several weeks of checkout and troubleshooting, the new compressor was ready for long-term, reliable operations. With a total of 110 pps in airflow now available, Glenn is well positioned to support the high-pressure air test requirements of our research customers.

System Mass Variation and Entropy Generation in 100k We Closed-Brayton-Cycle Space Power Systems

NASA Technical Reports Server (NTRS)

Barrett, Michael J.; Reid, Bryan M.

2004-01-01

State-of-the-art closed-Brayton-cycle (CBC) space power systems were modeled to study performance trends in a trade space characteristic of interplanetary orbiters. For working-fluid molar masses of 48.6, 39.9, and 11.9 kg/kmol, peak system pressures of 1.38 and 3.0 MPa and compressor pressure ratios ranging from 1.6 to 2.4, total system masses were estimated. System mass increased as peak operating pressure increased for all compressor pressure ratios and molar mass values examined. Minimum mass point comparison between 72 percent He at 1.38 MPa peak and 94 percent He at 3.0 MPa peak showed an increase in system mass of 14 percent. Converter flow loop entropy generation rates were calculated for 1.38 and 3.0 MPa peak pressure cases. Physical system behavior was approximated using a pedigreed NASA Glenn modeling code, Closed Cycle Engine Program (CCEP), which included realistic performance prediction for heat exchangers, radiators and turbomachinery.

System Mass Variation and Entropy Generation in 100-kWe Closed-Brayton-Cycle Space Power Systems

NASA Technical Reports Server (NTRS)

Barrett, Michael J.; Reid, Bryan M.

2004-01-01

State-of-the-art closed-Brayton-cycle (CBC) space power systems were modeled to study performance trends in a trade space characteristic of interplanetary orbiters. For working-fluid molar masses of 48.6, 39.9, and 11.9 kg/kmol, peak system pressures of 1.38 and 3.0 MPa and compressor pressure ratios ranging from 1.6 to 2.4, total system masses were estimated. System mass increased as peak operating pressure increased for all compressor pressure ratios and molar mass values examined. Minimum mass point comparison between 72 percent He at 1.38 MPa peak and 94 percent He at 3.0 MPa peak showed an increase in system mass of 14 percent. Converter flow loop entropy generation rates were calculated for 1.38 and 3.0 MPa peak pressure cases. Physical system behavior was approximated using a pedigreed NASA Glenn modeling code, Closed Cycle Engine Program (CCEP), which included realistic performance prediction for heat exchangers, radiators and turbomachinery.

Cell module and fuel conditioner development

NASA Technical Reports Server (NTRS)

Feret, J. M.

1982-01-01

The efforts performed to develop a phosphoric acid fuel cell (PAFC) stack design having a 10 kW power rating for operation at higher than atmospheric pressure based on the existing Mark II design configuration are described. The work involves: (1) Performance of pertinent functional analysis, trade studies and thermodynamic cycle analysis for requirements definition and system operating parameter selection purposes, (2) characterization of fuel cell materials and components, and performance testing and evaluation of the repeating electrode components, (3) establishment of the state-of-the-art manufacturing technology for all fuel cell components at Westinghouse and the fabrication of short stacks of various sites, and (4) development of a 10 kW PAFC stack design for higher pressure operation utilizing the top down systems engineering approach.

Low pressure electrospray ionization system and process for effective transmission of ions

DOEpatents

Tang, Keqi [Richland, WA; Page, Jason S [Kennewick, WA; Kelly, Ryan T [Wet Richland, WA; Smith, Richard D [Richland, WA

2010-03-02

A system and method are disclosed that provide up to complete transmission of ions between coupled stages with low effective ion losses. A novel "interfaceless" electrospray ionization system is further described that operates the electrospray at a reduced pressure such that standard electrospray sample solutions can be directly sprayed into an electrodynamic ion funnel which provides ion focusing and transmission of ions into a mass analyzer.

ORCHID - a computer simulation of the reliability of an NDE inspection system

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

Moles, M.D.C.

1987-03-01

CANDU pressurized heavy water reactors contain several hundred horizontally-mounted zirconium alloy pressure tubes. Following a pressure tube failure, a pressure tube inspection system called CIGARette was rapidly designed, manufactured and put in operation. Defects called hydride blisters were found to be the cause of the failure, and were detected using a combination of eddy current and ultrasonic scans. A number of improvements were made to CIGARette during the inspection period. The ORCHID computer program models the operation of the delivery system, eddy current and ultrasonic systems by imitating the on-reactor decision-making procedure. ORCHID predicts that during the early stage ofmore » development, less than one blistered tube in three would be detected, while less than one in two would be detected in the middle development stage. However, ORCHID predicts that during the late development stage, probability of detection will be over 90%, primarily due to the inclusion of axial ultrasonic scans (a procedural modification). Rotational and axial slip could severely reduce probability of detection. Comparison of CIGARette's inspection data with ORCHID's predictions indicate that the latter are compatible with the actual inspection results, through the numbers are small and data uncertain. It should be emphasized that the CIGARette system has been essentially replaced with the much more reliable CIGAR system.« less

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

NASA Technical Reports Server (NTRS)

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

2007-01-01

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

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

Morishita, Sadaharu; Goto, Tetsuya; Nagase, Masaaki

Multiprocesses in a single plasma process chamber with high throughput require precise, sequential, high-speed alteration of partial pressures of multiple gas species. A conventional gas-distribution system cannot realize this because the system seriously overshoots gas pressure immediately following valve operation. Furthermore, chamber volume and conductance of gas piping between the system and chamber should both be considered because they delay the stabilizing time of gas pressure. Therefore, the authors proposed a new gas-distribution system without overshoot by controlling gas flow rate based on pressure measurement, as well as a method of pulse-controlled gas injection immediately following valve operation. Time variationmore » of measured partial pressure agrees well with a calculation based on an equivalent-circuit model that represents the chamber and gas piping between the system and chamber. Using pulse-controlled gas injection, the stabilizing time can be reduced drastically to 0.6 s for HBr added to pure Ar plasma, and 0.7 s for O{sub 2} added to Ar/HBr plasma; without the pulse control, the stabilizing times are 3 and 7 s, respectively. In the O{sub 2} addition case, rapid stabilization can be achieved during the period of line/space pattern etching of poly-Si on a thin SiO{sub 2} film. This occurs without anomalous etching of the underlying SiO{sub 2} film or the Si substrate near the sidewall, thus obtaining a wide process margin with high throughput.« less

Investigation of the Effects of Facility Background Pressure on the Performance and Voltage-Current Characteristics of the High Voltage Hall Accelerator

NASA Technical Reports Server (NTRS)

Kamhawi, Hani; Huang, Wensheng; Haag, Thomas; Spektor, Rostislav

2014-01-01

The National Aeronautics and Space Administration (NASA) Science Mission Directorate In-Space Propulsion Technology office is sponsoring NASA Glenn Research Center to develop a 4 kW-class Hall thruster propulsion system for implementation in NASA science missions. A study was conducted to assess the impact of varying the facility background pressure on the High Voltage Hall Accelerator (HiVHAc) thruster performance and voltage-current characteristics. This present study evaluated the HiVHAc thruster performance in the lowest attainable background pressure condition at NASA GRC Vacuum Facility 5 to best simulate space-like conditions. Additional tests were performed at selected thruster operating conditions to investigate and elucidate the underlying physics that change during thruster operation at elevated facility background pressure. Tests were performed at background pressure conditions that are three and ten times higher than the lowest realized background pressure. Results indicated that the thruster discharge specific impulse and efficiency increased with elevated facility background pressure. The voltage-current profiles indicated a narrower stable operating region with increased background pressure. Experimental observations of the thruster operation indicated that increasing the facility background pressure shifted the ionization and acceleration zones upstream towards the thrusters anode. Future tests of the HiVHAc thruster are planned at background pressure conditions that are expected to be two to three times lower than what was achieved during this test campaign. These tests will not only assess the impact of reduced facility background pressure on thruster performance, voltage-current characteristics, and plume properties; but will also attempt to quantify the magnitude of the ionization.

Experimental and Analytical Determination of the Motion of Hydraulically Operated Valve Stems in Oil Engine Injection Systems

NASA Technical Reports Server (NTRS)

Gelalles, A G; Rothrock, A M

1930-01-01

This research on the pressure variations in the injection system of the N.A.C.A. Spray Photography Equipment and on the effects of these variations on the motion of the timing valve stem was undertaken in connection with the study of fuel injection systems for high-speed oil engines. The methods of analysis of the pressure variations and the general equation for the motion of the spring-loaded stem for the timing valve are applicable to a spring-loaded automatic injection valve, and in general to all hydraulically operated valves. A sample calculation for a spring-loaded automatic injection valve is included.

Study of cryogenic propellant systems for loading the space shuttle

NASA Technical Reports Server (NTRS)

Voth, R. O.; Steward, W. G.; Hall, W. J.

1974-01-01

Computer programs were written to model the liquid oxygen loading system for the space shuttle. The programs allow selection of input data through graphic displays which schematically depict the part of the system being modeled. The computed output is also displayed in the form of graphs and printed messages. Any one of six computation options may be selected. The first four of these pertain to thermal stresses, pressure surges, cooldown times, flow rates and pressures during cooldown. Options five and six deal with possible water hammer effects due to closing of valves, steady flow and transient response to changes in operating conditions after cooldown. Procedures are given for operation of the graphic display unit and minicomputer.

Safety management of complex research operators

NASA Technical Reports Server (NTRS)

Brown, W. J.

1981-01-01

Complex research and technology operations present varied potential hazards which are addressed in a disciplined, independent safety review and approval process. Potential hazards vary from high energy fuels to hydrocarbon fuels, high pressure systems to high voltage systems, toxic chemicals to radioactive materials and high speed rotating machinery to high powered lasers. A Safety Permit System presently covers about 600 potentially hazardous operations. The Safety Management Program described is believed to be a major factor in maintaining an excellent safety record.

Effect of operation parameters on the flux stabilization of gravity-driven membrane (GDM) filtration system for decentralized water supply.

PubMed

Tang, Xiaobin; Ding, An; Qu, Fangshu; Jia, Ruibao; Chang, Haiqing; Cheng, Xiaoxiang; Liu, Bin; Li, Guibai; Liang, Heng

2016-08-01

A pilot-scale gravity-driven membrane (GDM) filtration system under low gravitational pressure without any pre-treatment, backwash, flushing, or chemical cleaning was carried out to investigate the effect of operation parameters (including operation pressure, aeration mode, and intermittent filtration) on the effluent quality and permeability development. The results revealed that GDM system exhibited an efficient performance for the removal of suspended substances and organic compounds. The stabilization of flux occurred and the average values of stable flux were 6.6, 8.1, and 8.6 Lm(-2) h(-1) for pressures of 65, 120, and 200 mbar, respectively. In contrast, flux stabilization was not observed under continuous and intermittent aeration conditions. However, aeration (especially continuous aeration) was effective to improve flux and alleviate membrane fouling during 1-month operation. Moreover, intermittent filtration would influence the stabilization of permeate flux, resulting in a higher stable flux (ranging from 6 to 13 Lm(-2) h(-1)). The stable flux significantly improved with the increase of intermittent period. Additionally, GDM systems exhibited an efficient recovery of flux after simple physical cleaning and the analyses of resistance reversibility demonstrated that most of the total resistance was hydraulic reversible resistance (50-75 %). Therefore, it is expected that the results of this study can develop strategies to increase membrane permeability and reduce energy consumption in GDM systems for decentralized water supply.

46 CFR 39.30-1 - Operational requirements-TB/ALL.

Code of Federal Regulations, 2010 CFR

2010-10-01

... oxygen content of each area of that tank formed by each partial bulkhead must be measured at a point one... the requirements of this part. (b) The pressure drop through the vapor collection system from the most... rate versus the pressure drop. (c) If a vessel carries vapor hoses, the pressure drop through the hoses...

Space Operations Center system analysis study extension. Volume 1: Executive summary

NASA Technical Reports Server (NTRS)

1982-01-01

The analysis fo Space Operations Center (SOC) systems is summarized. Design considerations, configurations of the manned orbital space station, planned operational and research missions, and subsystem tradeoffs are considered. Integration into the space transportation system is discussed. A modular design concept permitting growth of the SOC as its functions are expanded is described. Additional considerations are special requirements for habitat modules, design modifications needed to operate in geosynchronous orbits, and use of the external tank for cryogenic propellant storage or as a pressurized hangar. A cost summary is presented.

Electronic field permeameter

DOEpatents

Chandler, Mark A.; Goggin, David J.; Horne, Patrick J.; Kocurek, Gary G.; Lake, Larry W.

1989-01-01

For making rapid, non-destructive permeability measurements in the field, a portable minipermeameter of the kind having a manually-operated gas injection tip is provided with a microcomputer system which operates a flow controller to precisely regulate gas flow rate to a test sample, and reads a pressure sensor which senses the pressure across the test sample. The microcomputer system automatically turns on the gas supply at the start of each measurement, senses when a steady-state is reached, collects and records pressure and flow rate data, and shuts off the gas supply immediately after the measurement is completed. Preferably temperature is also sensed to correct for changes in gas viscosity. The microcomputer system may also provide automatic zero-point adjustment, sensor calibration, over-range sensing, and may select controllers, sensors, and set-points for obtaining the most precise measurements. Electronic sensors may provide increased accuracy and precision. Preferably one microcomputer is used for sensing instrument control and data collection, and a second microcomputer is used which is dedicated to recording and processing the data, selecting the sensors and set-points for obtaining the most precise measurements, and instructing the user how to set-up and operate the minipermeameter. To provide mass data collection and user-friendly operation, the second microcomputer is preferably a lap-type portable microcomputer having a non-volatile or battery-backed CMOS memory.

Methods and apparatus of suppressing tube waves within a bore hole and seismic surveying systems incorporating same

DOEpatents

West, Phillip B.; Haefner, Daryl

2004-08-17

Methods and apparatus for attenuating waves in a bore hole, and seismic surveying systems incorporating the same. In one embodiment, an attenuating device includes a soft compliant bladder coupled to a pressurized gas source. A pressure regulating system reduces the pressure of the gas from the gas source prior to entering the bladder and operates in conjunction with the hydrostatic pressure of the fluid in a bore hole to maintain the pressure of the bladder at a specified pressure relative to the surrounding bore hole pressure. Once the hydrostatic pressure of the bore hole fluid exceeds that of the gas source, bore hole fluid may be admitted into a vessel of the gas source to further compress and displace the gas contained therein. In another embodiment, a water-reactive material may be used to provide gas to the bladder wherein the amount of gas generated by the water-reactive material may depend on the hydrostatic pressure of the bore hole fluid.

Methods and apparatus of suppressing tube waves within a bore hole and seismic surveying systems incorporating same

DOEpatents

West, Phillip B.; Haefner, Daryl

2005-12-13

Methods and apparatus for attenuating waves in a bore hole, and seismic surveying systems incorporating the same. In one embodiment, an attenuating device includes a soft compliant bladder coupled to a pressurized gas source. A pressure regulating system reduces the pressure of the gas from the gas source prior to entering the bladder and operates in conjunction with the hydrostatic pressure of the fluid in a bore hole to maintain the pressure of the bladder at a specified pressure relative to the surrounding bore hole pressure. Once the hydrostatic pressure of the bore hole fluid exceeds that of the gas source, bore hole fluid may be admitted into a vessel of the gas source to further compress and displace the gas contained therein. In another embodiment, a water-reactive material may be used to provide gas to the bladder wherein the amount of gas generated by the water-reactive material may depend on the hydrostatic pressure of the bore hole fluid.

Packaged Capacitive Pressure Sensor System for Aircraft Engine Health Monitoring

NASA Technical Reports Server (NTRS)

Scardelletti, Maximilian C.; Zorman, Christian A.

2016-01-01

This paper describes the development of a packaged silicon carbide (SiC) based MEMS pressure sensor system designed specifically for a conventional turbofan engine. The electronic circuit is based on a Clapp-type oscillator that incorporates a 6H-SiC MESFET, a SiCN MEMS capacitive pressure sensor, titanate MIM capacitors, wirewound inductors, and thick film resistors. The pressure sensor serves as the capacitor in the LC tank circuit, thereby linking pressure to the resonant frequency of the oscillator. The oscillator and DC bias circuitry were fabricated on an alumina substrate and secured inside a metal housing. The packaged sensing system reliably operates at 0 to 350 psi and 25 to 540C. The system has a pressure sensitivity of 6.8 x 10E-2 MHzpsi. The packaged system shows negligible difference in frequency response between 25 and 400C. The fully packaged sensor passed standard benchtop acceptance tests and was evaluated on a flight-worthy engine.

Study of Stage-wise Pressure Pulsation in an Electric Submersible Pump under Variable Frequency Operation at Shut-off Condition

NASA Astrophysics Data System (ADS)

Dhanasekaran, A.; Kumaraswamy, S.

2018-01-01

Pressure pulsation causes vibration in the Electric Submersible Pump (ESP) and affects the life and performance of its system. ESP systems are installed at depths ranging from a few meters to several hundred meters. Unlike pumps used on the surface, once they are installed they become inaccessible for maintenance or for any kind of diagnostic measurement that might be taken directly on them. Therefore a detailed knowledge of mean and fluctuating pressures is required to achieve an optimal pressure distribution inside the ESP. This paper presents the results of an experimental investigation of the stage-wise pulsating pressure in ESP at shut-off condition at different speeds. Experiments were conducted on a pump having five stages. A variable frequency drive was used to operate the pump at five different speeds. Piezoresistive transducers were mounted at each stage of ESP to capture the unsteady pressure signals. Fast Fourier Transformation was carried out on the pressure signals to convert into frequency domain and the spectra of pressure pulsation signals were analyzed. The obtained results indicated the existence of fundamental frequency corresponding to the speed of rotation times the number of impeller blades and of the whole series of harmonics of higher frequencies.

Pressure-Fed LOX/LCH4 Reaction Control System for Spacecraft: Transient Modeling and Thermal Vacuum Hotfire Test Results

NASA Technical Reports Server (NTRS)

Atwell, Matthew J.; Hurlbert, Eric A.; Melcher, J. C.; Morehead, Robert L.

2017-01-01

An integrated cryogenic liquid oxygen, liquid methane (LOX/LCH4) reaction control system (RCS) was tested at NASA Glenn Research Center's Plum Brook Station in the Spacecraft Propulsion Research Facility (B-2) under vacuum and thermal vacuum conditions. The RCS is a subsystem of the Integrated Cryogenic Propulsion Test Article (ICPTA), a pressure-fed LOX/LCH4 propulsion system composed of a single 2,800 lbf main engine, two 28 lbf RCS engines, and two 7 lbf RCS engines. Propellants are stored in four 48 inch diameter 5083 aluminum tanks that feed both the main engine and RCS engines in parallel. Helium stored cryogenically in a composite overwrapped pressure vessel (COPV) flows through a heat exchanger on the main engine before being used to pressurize the propellant tanks to a design operating pressure of 325 psi. The ICPTA is capable of simultaneous main engine and RCS operation. The RCS engines utilize a coil-on-plug (COP) ignition system designed for operation in a vacuum environment, eliminating corona discharge issues associated with a high voltage lead. There are two RCS pods on the ICPTA, with two engines on each pod. One of these two engines is a heritage flight engine from Project Morpheus. Its sea level nozzle was removed and replaced by an 85:1 nozzle machined using Inconel 718, resulting in a maximum thrust of 28 lbf under altitude conditions. The other engine is a scaled down version of the 28 lbf engine, designed to match the core and overall mixture ratios as well as other injector characteristics. This engine can produce a maximum thrust of 7 lbf with an 85:1 nozzle that was additively manufactured using Inconel 718. Both engines are film-cooled and capable of limited duration gas-gas and gas-liquid operation, as well as steady-state liquid-liquid operation. Each pod contains one of each version, such that two engines of the same thrust level can be fired as a couple on opposite pods. The RCS feed system is composed of symmetrical 3/8 inch lines that tap off of the main propellant manifold to send LOX and LCH4 outboard to the RCS pods. A Thermodynamic Vent System (TVS) is used to condition propellants at each pod by venting through an orifice and then routing the cold expansion products back through tubing that is welded along a large portion of the main RCS feed lines. Prior to final installation on the ICPTA, the RCS engines were tested in a small vacuum chamber at the Johnson Space Center (JSC) Energy Systems Test Area (ESTA) to verify functionality of the new COP ignition system and check out operation of the vacuum nozzles. After engine-level testing, the RCS engines were installed on the vehicle and a series of integrated hot-fire tests were performed at JSC consisting of various pulsing and steady-state firings as well as integrated main engine/RCS operation. The ICPTA was then integrated into the Plum Brook B-2 facility for vacuum and thermal/vacuum testing. Testing in the B-2 facility was composed of multiple thermal and pressure environments. The first set of tests were performed under ambient temperature and altitude pressure conditions. These tests consisted of a range of minimum impulse bit (MIB) pulsing sequences with low duty cycle, analogous to a coast phase in which the RCS is primarily used for station keeping. The primary goal of this sequence is to understand how propellant conditions were effected without an active TVS. In this scenario, consistent gas-gas operation is desirable since it results in a smaller MIB and more efficient propellant consumption. Multiple skin thermocouples are mounted on the feedlines, in addition to a submerged thermocouple on each commodity, in order to gather thermal data on the system. Higher duty cycle pulsing tests were then performed, analogous to an ascent or landing mission phase. The primary goal of this sequence was to examine how well the engines self-conditioned without active TVS when starting from a quiescent state. The TVS was then activated during some tests to demonstrate the capability to quickly condition the engines for higher pulsing demand scenarios. A thermocouple at the TVS outlet allows for the calculation of energy absorbed by the vented propellant. Lastly, tests with longer pulses and multiple engines firing either in sequence or simultaneously were run in order to gather transient system response data on waterhammer. Six total high-speed pressure transducers are installed on the RCS system, one sensor at the end of each propellant manifold line on the pods, and one at the tap-off location for each commodity. This will allow for the accurate characterization of waterhammer in the system under various propellant conditions and firing sequences. Other instrumentation for this test series includes nozzle throat thermocouples, chamber pressure measurement, heat soakback measurement, and tank wall plume impingement temperature measurement. The next set of tests were performed to demonstrate simultaneous main engine and RCS operation. Data from this test will be used to examine if there is any change to nominal operation of the RCS as a result of feed system interaction or other phenomenon. Some of these tests began under high vacuum conditions (target ambient pressure less than 1x10(exp -3) torr) and others began at altitude conditions. The last set of tests were performed with the B-2 cold wall active. Under these tests, many of the same low duty cycle MIB tests were repeated in order to characterize how propellant conditions changed with the lower heat leak. In this scenario the RCS manifold experiences much less heat leak, resulting in a change to how well the engines self-condition. As a result, an increase in maximum waterhammer pressures and a change in natural frequency of the system was expected due to higher density propellants. The lower heat leak should also result in a change to the MIB pulse profile, and data will be examined to understand how MIB repeatability is affected in the different operating environments. Parallel to the test efforts, a set of transient model development efforts were made to predict RCS performance. The primary effort was aimed at producing a SINDA/FLUINT model to predict propellant conditioning up to the engine inlet as a function of different environmental and operating parameters, with the goal of predicting chamber pressure, TVS performance, and propellant consumption over time. Preliminary results for this effort will be presented in comparison with test data. Additional modeling efforts were made using SINDA/FLUINT to predict waterhammer in the system since the software is capable of handling multiphase transient fluid dynamics. These results will be compared with the high-speed pressure transducer test data for validation purposes.

Compressed air energy storage system

DOEpatents

Ahrens, F.W.; Kartsounes, G.T.

An internal combustion reciprocating engine is operable as a compressor during slack demand periods utilizing excess power from a power grid to charge air into an air storage reservoir and as an expander during peak demand periods to feed power into the power grid utilizing air obtained from the air storage reservoir together with combustion reciprocating engine is operated at high pressure and a low pressure turbine and compressor are also employed for air compression and power generation.

Study on safety operation for large hydroelectric generator unit

NASA Astrophysics Data System (ADS)

Yan, Z. G.; Cui, T.; Zhou, L. J.; Zhi, F. L.; Wang, Z. W.

2012-11-01

Hydroelectric generator unit is a complex mechanical system which is composed of hydraulic turbine and electric generator. Rotary system is supported by the bearing bracket and the reinforced concrete structures, and vibration problem can't be avoided in the process of operating. Many large-scale hydroelectric units have been damaged because of the vibration problem in recent years. As the increase of the hydraulic turbine unit capacity and water head, the safe operation of hydraulic turbine has become a focus research in many countries. The operating characteristics of the hydraulic turbine have obvious differences at different working conditions. Based on the combination of field measurement and theoretical calculation, this paper shows a deep research on the safe operation of a large-scale Francis turbine unit. Firstly, the measurements of vibration, swing, pressure fluctuation and noise were carried out at 4 different heads. And also the relationships between vibrations and pressure fluctuations at different heads and working conditions were analysed deeply. Then the scientific prediction of safe operation for the unit at high head were done based on the CFD numerical calculation. Finally, this paper shows the division of the operating zone for the hydroelectric unit. According to the experimental results (vibrations, swings, pressure fluctuations and noise) as well as the theoretical results, the operating zone of the unit has been divided into three sections: prohibited operating zone, transition operating zone and safe operating zone. After this research was applied in the hydropower station, the security and economic efficiency of unit increased greatly, and enormous economic benefits and social benefits have been obtained.

Control method for mixed refrigerant based natural gas liquefier

DOEpatents

Kountz, Kenneth J.; Bishop, Patrick M.

2003-01-01

In a natural gas liquefaction system having a refrigerant storage circuit, a refrigerant circulation circuit in fluid communication with the refrigerant storage circuit, and a natural gas liquefaction circuit in thermal communication with the refrigerant circulation circuit, a method for liquefaction of natural gas in which pressure in the refrigerant circulation circuit is adjusted to below about 175 psig by exchange of refrigerant with the refrigerant storage circuit. A variable speed motor is started whereby operation of a compressor is initiated. The compressor is operated at full discharge capacity. Operation of an expansion valve is initiated whereby suction pressure at the suction pressure port of the compressor is maintained below about 30 psig and discharge pressure at the discharge pressure port of the compressor is maintained below about 350 psig. Refrigerant vapor is introduced from the refrigerant holding tank into the refrigerant circulation circuit until the suction pressure is reduced to below about 15 psig, after which flow of the refrigerant vapor from the refrigerant holding tank is terminated. Natural gas is then introduced into a natural gas liquefier, resulting in liquefaction of the natural gas.

Space shuttle pogo studies. [systems stability

NASA Technical Reports Server (NTRS)

Coppolino, R. N.; Lock, M. H.; Rubin, S.

1977-01-01

Topics covered include: (1) pogo suppression for main propulsion subsystem operation; (2) application of quarter-scale low pressure oxidizer turbopump transfer functions; (3) pogo stability during orbital maneuvering subsystem operation; and (4) errors in frequency response measurements.

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

Code of Federal Regulations, 2012 CFR

2012-07-01

... OF THE INTERIOR OFFSHORE OIL AND GAS AND SULPHUR OPERATIONS IN THE OUTER CONTINENTAL SHELF Oil and Gas Drilling Operations Blowout Preventer (bop) System Requirements § 250.448 What are the BOP...

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

Code of Federal Regulations, 2013 CFR

2013-07-01

... OF THE INTERIOR OFFSHORE OIL AND GAS AND SULPHUR OPERATIONS IN THE OUTER CONTINENTAL SHELF Oil and Gas Drilling Operations Blowout Preventer (bop) System Requirements § 250.448 What are the BOP...

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

Code of Federal Regulations, 2014 CFR

2014-07-01

... OF THE INTERIOR OFFSHORE OIL AND GAS AND SULPHUR OPERATIONS IN THE OUTER CONTINENTAL SHELF Oil and Gas Drilling Operations Blowout Preventer (bop) System Requirements § 250.448 What are the BOP...

Impact of air conditioning system operation on increasing gases emissions from automobile

NASA Astrophysics Data System (ADS)

Burciu, S. M.; Coman, G.

2016-08-01

The paper presents a study concerning the influence of air conditioning system operation on the increase of gases emissions from cars. The study focuses on urban operating regimes of the automobile, regimes when the engines have low loads or are operating at idling. Are presented graphically the variations of pollution emissions (CO, CO2, HC) depending of engine speed and the load on air conditioning system. Additionally are presented, injection duration, throttle position, the mechanical power required by the compressor of air conditioning system and the refrigerant pressure variation on the discharge path, according to the stage of charging of the air conditioning system.

Shock-operated valve would automatically protect fluid systems

NASA Technical Reports Server (NTRS)

Branum, L. W.; Wells, G. H.

1966-01-01

Glandless valve shuts down high-pressure fluid systems when severe shock from an explosion or earthquake occurs. The valve uses a pendulum to support the valve closure plug in the open position. When jarred, the valve body is moved relative to the pendulum and the plug support is displaced, allowing the plug to seat and be held by spring pressure.

System for operating solid oxide fuel cell generator on diesel fuel

NASA Technical Reports Server (NTRS)

Singh, Prabhu (Inventor); George, Raymond A. (Inventor)

1997-01-01

A system is provided for operating a solid oxide fuel cell generator on diesel fuel. The system includes a hydrodesulfurizer which reduces the sulfur content of commercial and military grade diesel fuel to an acceptable level. Hydrogen which has been previously separated from the process stream is mixed with diesel fuel at low pressure. The diesel/hydrogen mixture is then pressurized and introduced into the hydrodesulfurizer. The hydrodesulfurizer comprises a metal oxide such as ZnO which reacts with hydrogen sulfide in the presence of a metal catalyst to form a metal sulfide and water. After desulfurization, the diesel fuel is reformed and delivered to a hydrogen separator which removes most of the hydrogen from the reformed fuel prior to introduction into a solid oxide fuel cell generator. The separated hydrogen is then selectively delivered to the diesel/hydrogen mixer or to a hydrogen storage unit. The hydrogen storage unit preferably comprises a metal hydride which stores hydrogen in solid form at low pressure. Hydrogen may be discharged from the metal hydride to the diesel/hydrogen mixture at low pressure upon demand, particularly during start-up and shut-down of the system.

Dynamics of the precessing vortex rope and its interaction with the system at Francis turbines part load operating conditions

NASA Astrophysics Data System (ADS)

Favrel, A.; Müller, A.; Landry, C.; Gomes, J.; Yamamoto, K.; Avellan, F.

2017-04-01

At part load conditions, Francis turbines experience the formation of a cavitation vortex rope at the runner outlet whose precession acts as a pressure excitation source for the hydraulic circuit. This can lead to hydro-acoustic resonances characterized by high pressure pulsations, as well as torque and output power fluctuations. This study highlights the influence of the discharge factor on both the vortex parameters and the pressure excitation source by performing Particle Image Velocimetry (PIV) and pressure measurements. Moreover, it is shown that the occurrence of hydro-acoustic resonances in cavitation conditions mainly depend on the swirl degree of the flow independently of the speed factor. Empirical laws linking both natural and precession frequencies with the operating parameters of the machine are, then, derived, enabling the prediction of resonance conditions on the complete part load operating range of the turbine.

Pressurization System Modeling for a Generic Bimese Two- Stage-to-Orbit Reusable Launch Vehicle

NASA Technical Reports Server (NTRS)

Mazurkivich, Pete; Chandler, Frank; Nguyen, Han

2005-01-01

A pressurization system model was developed for a generic bimese Two-Stage-to-orbit Reusable Launch Vehicle using a cross-feed system and operating with densified propellants. The model was based on the pressurization system model for a crossfeed subscale water test article and was validated with test data obtained from the test article. The model consists of the liquid oxygen and liquid hydrogen pressurization models, each made up of two submodels, Booster and Orbiter tank pressurization models. The tanks are controlled within a 0.2-psi band and pressurized on the ground with ambient helium and autogenously in flight with gaseous oxygen and gaseous hydrogen. A 15-psi pressure difference is maintained between the Booster and Orbiter tanks to ensure crossfeed check valve closure before Booster separation. The analysis uses an ascent trajectory generated for a generic bimese vehicle and a tank configuration based on the Space Shuttle External Tank. It determines the flow rates required to pressurize the tanks on the ground and in flight, and demonstrates the model's capability to analyze the pressurization system performance of a full-scale bimese vehicle with densified propellants.

Rotating pressure measurement system using an on board calibration standard

NASA Technical Reports Server (NTRS)

Senyitko, Richard G.; Blumenthal, Philip Z.; Freedman, Robert J.

1991-01-01

A computer-controlled multichannel pressure measurement system was developed to acquire detailed flow field measurements on board the Large Low Speed Centrifugal Compressor Research Facility at the NASA Lewis Research Center. A pneumatic slip ring seal assembly is used to transfer calibration pressures to a reference standard transducer on board the compressor rotor in order to measure very low differential pressures with the high accuracy required. A unique data acquisition system was designed and built to convert the analog signal from the reference transducer to the variable frequency required by the multichannel pressure measurement system and also to provide an output for temperature control of the reference transducer. The system also monitors changes in test cell barometric pressure and rotating seal leakage and provides an on screen warning to the operator if limits are exceeded. The methods used for the selection and testing of the the reference transducer are discussed, and the data acquisition system hardware and software design are described. The calculated and experimental data for the system measurement accuracy are also presented.

14 CFR 31.49 - Control systems.

Code of Federal Regulations, 2010 CFR

2010-01-01

... minute when the balloon is at its maximum operating pressure. (d) Each hot air balloon must have a means to allow the controlled release of hot air during flight. (e) Each hot air balloon must have a means... STANDARDS: MANNED FREE BALLOONS Design Construction § 31.49 Control systems. (a) Each control must operate...

40 CFR 63.9804 - What are my monitoring system installation, operation, and maintenance requirements?

Code of Federal Regulations, 2012 CFR

2012-07-01

..., wiring, power supply, and data acquisition and recording system that are compatible with the output... temperature CPMS that is used to monitor the combustion chamber temperature of a thermal oxidizer or the... where it is easily recognized by plant operating personnel. (6) For positive pressure fabric filter...

49 CFR 393.48 - Brakes to be operative.

Code of Federal Regulations, 2010 CFR

2010-10-01

... motor vehicle may be equipped with a device to reduce the front wheel braking effort (or in the case of... operable by the driver except upon application of the control that activates the braking system. The device... with air brakes) or 85 percent of the maximum system pressure (for vehicles which are not equipped with...

A high-temperature wideband pressure transducer

NASA Technical Reports Server (NTRS)

Zuckerwar, A. J.

1976-01-01

The problem of operating a condenser microphone as a terminal element of a half wavelength transmission line was dealt with; the environment in which the microphone operates necessitates a 25 foot separation from its supporting electronics. A theoretical analysis of the microphone-cable system, substantiated by laboratory tests, provided criteria to optimize system gain.

Approach for Mitigating Pressure Garment Design Risks in a Mobile Lunar Surface Systems Architecture

NASA Technical Reports Server (NTRS)

Aitchison, Lindsay

2009-01-01

The stated goals of the 2004 Vision for Space Exploration focus on establishing a human presence throughout the solar system beginning with the establishment of a permanent human presence on the Moon. However, the precise objectives to be accomplished on the lunar surface and the optimal system architecture to achieve those objectives have been a topic of much debate since the inception of the Constellation Program. There are two basic styles of system architectures being traded at the Programmatic level: a traditional large outpost that would focus on techniques for survival off our home planet and a greater depth of exploration within one area, or a mobile approach- akin to a series of nomadic camps- that would allow greater breadth of exploration opportunities. The traditional outpost philosophy is well within the understood pressure garment design space with respect to developing interfaces and operational life cycle models. The mobile outpost, however, combines many unknowns with respect to pressure garment performance and reliability that could dramatically affect the cost and schedule risks associated with the Constellation space suit system. This paper provides an overview of the concepts being traded for a mobile architecture from the operations and hardware implementation perspective, describes the primary risks to the Constellation pressure garment associated with each of the concepts, and summarizes the approach necessary to quantify the pressure garment design risks to enable the Constellation Program to make informed decisions when deciding on an overall lunar surface systems architecture.

40 CFR 265.195 - Inspections.

Code of Federal Regulations, 2012 CFR

2012-07-01

... of hazardous waste (e.g., wet spots, dead vegetation). (c) Owners or operators of tank systems that... operating day, data gathered from monitoring and leak detection equipment (e.g., pressure or temperature... must inspect at least once each operating day: (1) Overfill/spill control equipment (e.g., waste-feed...

40 CFR 265.195 - Inspections.

Code of Federal Regulations, 2010 CFR

2010-07-01

... of hazardous waste (e.g., wet spots, dead vegetation). (c) Owners or operators of tank systems that... operating day, data gathered from monitoring and leak detection equipment (e.g., pressure or temperature... must inspect at least once each operating day: (1) Overfill/spill control equipment (e.g., waste-feed...

40 CFR 265.195 - Inspections.

Code of Federal Regulations, 2013 CFR

2013-07-01

... of hazardous waste (e.g., wet spots, dead vegetation). (c) Owners or operators of tank systems that... operating day, data gathered from monitoring and leak detection equipment (e.g., pressure or temperature... must inspect at least once each operating day: (1) Overfill/spill control equipment (e.g., waste-feed...

40 CFR 265.195 - Inspections.

Code of Federal Regulations, 2014 CFR

2014-07-01

... of hazardous waste (e.g., wet spots, dead vegetation). (c) Owners or operators of tank systems that... operating day, data gathered from monitoring and leak detection equipment (e.g., pressure or temperature... must inspect at least once each operating day: (1) Overfill/spill control equipment (e.g., waste-feed...

40 CFR 265.195 - Inspections.

Code of Federal Regulations, 2011 CFR

2011-07-01

... of hazardous waste (e.g., wet spots, dead vegetation). (c) Owners or operators of tank systems that... operating day, data gathered from monitoring and leak detection equipment (e.g., pressure or temperature... must inspect at least once each operating day: (1) Overfill/spill control equipment (e.g., waste-feed...

Investigation of the Effects of Facility Background Pressure on the Performance and Voltage-Current Characteristics of the High Voltage Hall Accelerator

NASA Technical Reports Server (NTRS)

Kamhawi, Hani; Huang, Wensheng; Haag, Thomas; Spektor, Rostislav

2014-01-01

The National Aeronautics and Space Administration (NASA) Science Mission Directorate In-Space Propulsion Technology office is sponsoring NASA Glenn Research Center to develop a 4 kW-class Hall thruster propulsion system for implementation in NASA science missions. A study was conducted to assess the impact of varying the facility background pressure on the High Voltage Hall Accelerator (HiVHAc) thruster performance and voltage-current characteristics. This present study evaluated the HiVHAc thruster performance in the lowest attainable background pressure condition at NASA GRC Vacuum Facility 5 to best simulate space-like conditions. Additional tests were performed at selected thruster operating conditions to investigate and elucidate the underlying physics that change during thruster operation at elevated facility background pressure. Tests were performed at background pressure conditions that are three and ten times higher than the lowest realized background pressure. Results indicated that the thruster discharge specific impulse and efficiency increased with elevated facility background pressure. The voltage-current profiles indicated a narrower stable operating region with increased background pressure. Experimental observations of the thruster operation indicated that increasing the facility background pressure shifted the ionization and acceleration zones upstream towards the thruster's anode. Future tests of the HiVHAc thruster are planned at background pressure conditions that are expected to be two to three times lower than what was achieved during this test campaign. These tests will not only assess the impact of reduced facility background pressure on thruster performance, voltage-current characteristics, and plume properties; but will also attempt to quantify the magnitude of the ionization and acceleration zones upstream shifting as a function of increased background pressure.

Device to lower NOx in a gas turbine engine combustion system

DOEpatents

Laster, Walter R; Schilp, Reinhard; Wiebe, David J

2015-02-24

An emissions control system for a gas turbine engine including a flow-directing structure (24) that delivers combustion gases (22) from a burner (32) to a turbine. The emissions control system includes: a conduit (48) configured to establish fluid communication between compressed air (22) and the combustion gases within the flow-directing structure (24). The compressed air (22) is disposed at a location upstream of a combustor head-end and exhibits an intermediate static pressure less than a static pressure of the combustion gases within the combustor (14). During operation of the gas turbine engine a pressure difference between the intermediate static pressure and a static pressure of the combustion gases within the flow-directing structure (24) is effective to generate a fluid flow through the conduit (48).

Generation and delivery device for ozone gas and ozone dissolved in water

NASA Technical Reports Server (NTRS)

Andrews, Craig C. (Inventor); Murphy, Oliver J. (Inventor)

2006-01-01

The present invention provides an ozone generation and delivery system that lends itself to small scale applications and requires very low maintenance. The system includes an anode reservoir and a cathode phase separator each having a hydrophobic membrane to allow phase separation of produced gases from water. The system may be configured to operate passively with no moving parts or in a self-pressurizing manner with the inclusion of a pressure controlling device or valve in the gas outlet of the anode reservoir. The hydrogen gas, ozone gas and water containing ozone may be delivered under pressure.

Generation and delivery device for ozone gas and ozone dissolved in water

NASA Technical Reports Server (NTRS)

Andrews, Craig C. (Inventor); Rogers, Thomas D. (Inventor); Murphy, Oliver J. (Inventor)

1999-01-01

The present invention provides an ozone generation and delivery system that lends itself to small scale applications and requires very low maintenance. The system includes an anode reservoir and a cathode phase separator each having a hydrophobic membrane to allow phase separation of produced gases from water. The system may be configured to operate passively with no moving parts or in a self-pressurizing manner with the inclusion of a pressure controlling device or valve in the gas outlet of the anode reservoir. The hydrogen gas, ozone gas and water containing ozone may be delivered under pressure.

Design and adaptation of a novel supercritical extraction facility for operation in a glove box for recovery of radioactive elements

NASA Astrophysics Data System (ADS)

Kumar, V. Suresh; Kumar, R.; Sivaraman, N.; Ravisankar, G.; Vasudeva Rao, P. R.

2010-09-01

The design and development of a novel supercritical extraction experimental facility adapted for safe operation in a glove box for the recovery of radioactive elements from waste is described. The apparatus incorporates a high pressure extraction vessel, reciprocating pumps for delivering supercritical fluid and reagent, a back pressure regulator, and a collection chamber. All these components of the system have been specially designed for glove box adaptation and made modular to facilitate their replacement. Confinement of these materials must be ensured in a glove box to protect the operator and prevent contamination to the work area. Since handling of radioactive materials under high pressure (30 MPa) and temperature (up to 333 K) is involved in this process, the apparatus needs elaborate safety features in the design of the equipment, as well as modification of a standard glove box to accommodate the system. As a special safety feature to contain accidental leakage of carbon dioxide from the extraction vessel, a safety vessel has been specially designed and placed inside the glove box. The extraction vessel was enclosed in the safety vessel. The safety vessel was also incorporated with pressure sensing and controlling device.

Surface Pressure Dependencies in the GEOS-Chem-Adjoint System and the Impact of the GEOS-5 Surface Pressure on CO2 Model Forecast

NASA Technical Reports Server (NTRS)

Lee, Meemong; Weidner, Richard

2016-01-01

In the GEOS-Chem Adjoint (GCA) system, the total (wet) surface pressure of the GEOS meteorology is employed as dry surface pressure, ignoring the presence of water vapor. The Jet Propulsion Laboratory (JPL) Carbon Monitoring System (CMS) research team has been evaluating the impact of the above discrepancy on the CO2 model forecast and the CO2 flux inversion. The JPL CMS research utilizes a multi-mission assimilation framework developed by the Multi-Mission Observation Operator (M2O2) research team at JPL extending the GCA system. The GCA-M2O2 framework facilitates mission-generic 3D and 4D-variational assimilations streamlining the interfaces to the satellite data products and prior emission inventories. The GCA-M2O2 framework currently integrates the GCA system version 35h and provides a dry surface pressure setup to allow the CO2 model forecast to be performed with the GEOS-5 surface pressure directly or after converting it to dry surface pressure.

Surface Pressure Dependencies in the Geos-Chem-Adjoint System and the Impact of the GEOS-5 Surface Pressure on CO2 Model Forecast

NASA Technical Reports Server (NTRS)

Lee, Meemong; Weidner, Richard

2016-01-01

In the GEOS-Chem Adjoint (GCA) system, the total (wet) surface pressure of the GEOS meteorology is employed as dry surface pressure, ignoring the presence of water vapor. The Jet Propulsion Laboratory (JPL) Carbon Monitoring System (CMS) research team has been evaluating the impact of the above discrepancy on the CO2 model forecast and the CO2 flux inversion. The JPL CMS research utilizes a multi-mission assimilation framework developed by the Multi-Mission Observation Operator (M2O2) research team at JPL extending the GCA system. The GCA-M2O2 framework facilitates mission-generic 3D and 4D-variational assimilations streamlining the interfaces to the satellite data products and prior emission inventories. The GCA-M2O2 framework currently integrates the GCA system version 35h and provides a dry surface pressure setup to allow the CO2 model forecast to be performed with the GEOS-5 surface pressure directly or after converting it to dry surface pressure.

Numerical prediction of micro-channel LD heat sink operated with antifreeze based on CFD method

NASA Astrophysics Data System (ADS)

Liu, Gang; Liu, Yang; Wang, Chao; Wang, Wentao; Wang, Gang; Tang, Xiaojun

2014-12-01

To theoretically study the feasibility of antifreeze coolants applied as cooling fluids for high power LD heat sink, detailed Computational Fluid Dynamics (CFD) analysis of liquid cooled micro-channels heat sinks is presented. The performance operated with antifreeze coolant (ethylene glycol aqueous solution) compared with pure water are numerical calculated for the heat sinks with the same micro-channels structures. The maximum thermal resistance, total pressure loss (flow resistance), thermal resistance vs. flow-rate, and pressure loss vs. flow-rate etc. characteristics are numerical calculated. The results indicate that the type and temperature of coolants plays an important role on the performance of heat sinks. The whole thermal resistance and pressure loss of heat sinks increase significantly with antifreeze coolants compared with pure water mainly due to its relatively lower thermal conductivity and higher fluid viscosity. The thermal resistance and pressure loss are functions of the flow rate and operation temperature. Increasing of the coolant flow rate can reduce the thermal resistance of heat sinks; meanwhile increase the pressure loss significantly. The thermal resistance tends to a limit with increasing flow rate, while the pressure loss tends to increase exponentially with increasing flow rate. Low operation temperature chiefly increases the pressure loss rather than thermal resistance due to the remarkable increasing of fluid viscosity. The actual working point of the cooling circulation system can be determined on the basis of the pressure drop vs. flow rate curve for the micro-channel heat sink and that for the circulation system. In the same system, if the type or/and temperature of the coolant is changed, the working point is accordingly influenced, that is, working flow rate and pressure is changed simultaneously, due to which the heat sink performance is influenced. According to the numerical simulation results, if ethylene glycol aqueous solution is applied instead of pure water as the coolant under the same or a higher working temperature, the available output of optical power will decrease due to the worse heat sink performance; if applied under a lower working temperature(0 °C, －20 °C), although the heat sink performance become worse, however the temperature difference of heat transfer rises more significantly, the available output of optical power will increase on the contrary.

Flow-rate independent gas-mixing system for drift chambers, using solenoid valves

NASA Astrophysics Data System (ADS)

Sugano, K.

1991-03-01

We describe an inexpensive system for mixing argon and ethane gas for drift chambers which was used for an experiment at Fermilab. This system is based on the idea of intermittent mixing of gases with fixed mixing flow rates. A dual-action pressure switch senses the pressure in a mixed gas reservoir tank and operates solenoid valves to control mixing action and regulate reservoir pressure. This system has the advantages that simple controls accurately regulate the mixing ratio and that the mixing ratio is nearly flow-rate independent without readjustments. We also report the results of the gas analysis of various samplings, and the reliability of the system in long-term running.

Calibration of the Total and Static Pressure Transducers in the DSTO Transonic Wind Tunnel

DTIC Science & Technology

2010-08-01

handled by the ActiveX control MSCOMM32.OCX which is not part of the Microsoft Windows operating system. It is, however, included as part of the...implemented new measures to register ActiveX controls in its Windows suite of operating systems, which has made the above file obsolete and it could no...longer be used if the Windows operating system were updated. If this is the case, then the new version of ActiveX control files can be installed using

Renewable energy powered membrane technology. 1. Development and characterization of a photovoltaic hybrid membrane system.

PubMed

Schäfer, A I; Broeckmann, A; Richards, B S

2007-02-01

In isolated communities where potable water sources as well as energy grids are limited or nonexistent, treating brackish groundwater aquifers with small-scale desalination systems can be a viable alternative to existing water infrastructures. Given the unavailability of power in many such situations, renewable energy is an obvious solution to power such systems. However, renewable energy is an intermittent power supply and with regards to the performance of intermittently operated desalination systems, only very limited experience exists, both with regards to efficiency as well as water quality. In this paper, this lack of knowledge is addressed by evaluating a system operated with varying parameters (pressure and flow) with constant power as a step toward defining a safe operating window, and they provide a basis for interpreting future data obtained with a renewable energy source. Field trials were performed on a brackish (5300 mg/L TDS; 8290 microS/cm) bore in Central Australia with a photovoltaic-powered membrane filtration (PV-membrane) system. Four nanofiltration and reverse osmosis membranes (BW30, ESPA4, NF90, TFC-S) and a number of operation parameter combinations (transmembrane pressure, feed flow, TFC-S) and operating parameters transmembrane pressure and feed flow were investigated to find the best operating conditions for maximum drinking water production and minimum specific energy consumption (SEC). The ESPA4 membrane performed best for this brackish source, producing 250 L/h of excellent drinking water (257 mg/L TDS; 400 microS/ cm) at an SEC of 1.2 kWh/m3. The issue of brine disposal or reuse is also discussed and the article compares the salinity of the produced brine with livestock water. Since the feedwater is disinfected physically using ultrafiltration (UF), the brine is free from bacteria and most viruses and hence can be seen more as a reusable product stream than a waste stream with a disposal problem.

Pressure activated interconnection of micro transfer printed components

NASA Astrophysics Data System (ADS)

Prevatte, Carl; Guven, Ibrahim; Ghosal, Kanchan; Gomez, David; Moore, Tanya; Bonafede, Salvatore; Raymond, Brook; Trindade, António Jose; Fecioru, Alin; Kneeburg, David; Meitl, Matthew A.; Bower, Christopher A.

2016-05-01

Micro transfer printing and other forms of micro assembly deterministically produce heterogeneously integrated systems of miniaturized components on non-native substrates. Most micro assembled systems include electrical interconnections to the miniaturized components, typically accomplished by metal wires formed on the non-native substrate after the assembly operation. An alternative scheme establishing interconnections during the assembly operation is a cost-effective manufacturing method for producing heterogeneous microsystems, and facilitates the repair of integrated microsystems, such as displays, by ex post facto addition of components to correct defects after system-level tests. This letter describes pressure-concentrating conductor structures formed on silicon (1 0 0) wafers to establish connections to preexisting conductive traces on glass and plastic substrates during micro transfer printing with an elastomer stamp. The pressure concentrators penetrate a polymer layer to form the connection, and reflow of the polymer layer bonds the components securely to the target substrate. The experimental yield of series-connected test systems with >1000 electrical connections demonstrates the suitability of the process for manufacturing, and robustness of the test systems against exposure to thermal shock, damp heat, and mechanical flexure shows reliability of the resulting bonds.

An integrated exhaust gas analysis system with self-contained data processing and automatic calibration

NASA Technical Reports Server (NTRS)

Anderson, R. C.; Summers, R. L.

1981-01-01

An integrated gas analysis system designed to operate in automatic, semiautomatic, and manual modes from a remote control panel is described. The system measures the carbon monoxide, oxygen, water vapor, total hydrocarbons, carbon dioxide, and oxides of nitrogen. A pull through design provides increased reliability and eliminates the need for manual flow rate adjustment and pressure correction. The system contains two microprocessors to range the analyzers, calibrate the system, process the raw data to units of concentration, and provides information to the facility research computer and to the operator through terminal and the control panels. After initial setup, the system operates for several hours without significant operator attention.

Solenoid Driven Pressure Valve System: Toward Versatile Fluidic Control in Paper Microfluidics.

PubMed

Kim, Taehoon H; Hahn, Young Ki; Lee, Jungmin; van Noort, Danny; Kim, Minseok S

2018-02-20

As paper-based diagnostics has become predominantly driven by more advanced microfluidic technology, many of the research efforts are still focused on developing reliable and versatile fluidic control devices, apart from improving sensitivity and reproducibility. In this work, we introduce a novel and robust paper fluidic control system enabling versatile fluidic control. The system comprises a linear push-pull solenoid and an Arduino Uno microcontroller. The precisely controlled pressure exerted on the paper stops the flow. We first determined the stroke distance of the solenoid to obtain a constant pressure while examining the fluidic time delay as a function of the pressure. Results showed that strips of grade 1 chromatography paper had superior reproducibility in fluid transport. Next, we characterized the reproducibility of the fluidic velocity which depends on the type and grade of paper used. As such, we were able to control the flow velocity on the paper and also achieve a complete stop of flow with a pressure over 2.0 MPa. Notably, after the actuation of the pressure driven valve (PDV), the previously pressed area regained its original flow properties. This means that, even on a previously pressed area, multiple valve operations can be successfully conducted. To the best of our knowledge, this is the first demonstration of an active and repetitive valve operation in paper microfluidics. As a proof of concept, we have chosen to perform a multistep detection system in the form of an enzyme-linked immunosorbent assay with mouse IgG as the target analyte.

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

Code of Federal Regulations, 2011 CFR

2011-07-01

... ENFORCEMENT, DEPARTMENT OF THE INTERIOR OFFSHORE OIL AND GAS AND SULPHUR OPERATIONS IN THE OUTER CONTINENTAL SHELF Oil and Gas Drilling Operations Blowout Preventer (bop) System Requirements § 250.448 What are the...

Sample preparation system for microfluidic applications

DOEpatents

Mosier, Bruce P [San Francisco, CA; Crocker, Robert W [Fremont, CA; Patel, Kamlesh D [Dublin, CA; Harnett, Cindy K [Livermore, CA

2007-05-08

An apparatus that couples automated injection with flow feedback to provide nanoliter accuracy in controlling microliter volumes. The apparatus comprises generally a source of hydraulic fluid pressure, a fluid isolator joined to the outlet of the hydraulic pressure source and a flow sensor to provide pressure-driven analyte metering. For operation generally and particularly in microfluidic systems the hydraulic pressure source is typically an electrokinetic (EK) pump that incorporates gasless electrodes. The apparatus is capable of metering sub-microliter volumes at flowrates of 1 100 .mu.L/min into microsystem load pressures of up to 1000 50 psi, respectively. Flowrates can be specified within 0.5 .mu.L/min and volumes as small as 80 nL can be metered.

The Development and Implementation of a Cryogenic Pressure Sensitive Paint System in the National Transonic Facility

NASA Technical Reports Server (NTRS)

Watkins, A. Neal; Leighty, Bradley D.; Lipford, William E.; Oglesby, Donald M.; Goodman, Kyle Z.; Goad, William K.; Goad, Linda R.; Massey, Edward A.

2009-01-01

The Pressure Sensitive Paint (PSP) method was used to measure global surface pressures on a model at full-scale flight Reynolds numbers. In order to achieve these conditions, the test was carried out at the National Transonic Facility (NTF) operating under cryogenic conditions in a nitrogen environment. The upper surface of a wing on a full-span 0.027 scale commercial transport was painted with a porous PSP formulation and tested at 120K. Data was acquired at Mach 0.8 with a total pressure of 200 kPa, resulting in a Reynolds number of 65 x 106/m. Oxygen, which is required for PSP operation, was injected using dry air so that the oxygen concentration in the flow was approximately 1535 ppm. Results show qualitative agreement with expected results. This preliminary test is the first time that PSP has been successfully deployed to measure global surface pressures at cryogenic condition in the NTF. This paper will describe the system as installed, the results obtained from the test, as well as proposed upgrades and future tests.

Gas loading apparatus for the Paris-Edinburgh press

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

Bocian, A.; Kamenev, K. V.; Bull, C. L.

2010-09-15

We describe the design and operation of an apparatus for loading gases into the sample volume of the Paris-Edinburgh press at room temperature and high pressure. The system can be used for studies of samples loaded as pure or mixed gases as well as for loading gases as pressure-transmitting media in neutron-scattering experiments. The apparatus consists of a high-pressure vessel and an anvil holder with a clamp mechanism. The vessel, designed to operate at gas pressures of up to 150 MPa, is used for applying the load onto the anvils located inside the clamp. This initial load is sufficient formore » sealing the pressurized gas inside the sample containing gasket. The clamp containing the anvils and the sample is then transferred into the Paris-Edinburgh press by which further load can be applied to the sample. The clamp has apertures for scattered neutron beams and remains in the press for the duration of the experiment. The performance of the gas loading system is illustrated with the results of neutron-diffraction experiments on compressed nitrogen.« less

Scanning tunneling microscope assembly, reactor, and system

DOEpatents

Tao, Feng; Salmeron, Miquel; Somorjai, Gabor A

2014-11-18

An embodiment of a scanning tunneling microscope (STM) reactor includes a pressure vessel, an STM assembly, and three spring coupling objects. The pressure vessel includes a sealable port, an interior, and an exterior. An embodiment of an STM system includes a vacuum chamber, an STM reactor, and three springs. The three springs couple the STM reactor to the vacuum chamber and are operable to suspend the scanning tunneling microscope reactor within the interior of the vacuum chamber during operation of the STM reactor. An embodiment of an STM assembly includes a coarse displacement arrangement, a piezoelectric fine displacement scanning tube coupled to the coarse displacement arrangement, and a receiver. The piezoelectric fine displacement scanning tube is coupled to the coarse displacement arrangement. The receiver is coupled to the piezoelectric scanning tube and is operable to receive a tip holder, and the tip holder is operable to receive a tip.

Liquid crystalline fiber optic colorimeter for hydrostatic pressure measurement

NASA Astrophysics Data System (ADS)

Wolinski, Tomasz R.; Bajdecki, Waldemar K.; Domanski, Andrzej W.; Karpierz, Miroslaw A.; Konopka, Witold; Nasilowski, T.; Sierakowski, Marek W.; Swillo, Marcin; Dabrowski, Roman S.; Nowinowski-Kruszelnicki, Edward; Wasowski, Janusz

2001-08-01

This paper presents results of tests performed on a fiber optic system of liquid crystalline transducer for hydrostatic pressure monitoring based on properties of colorimetry. The system employs pressure-induced deformations occurring in liquid crystalline (LC) cells configured in a homogeneous Frederiks geometry. The sensor is compared of a round LC cell placed inside a specially designed pressure chamber. As a light source we used a typical diode operating at red wavelength and modulated using standard techniques. The pressure transducer was connected to a computer with a specially designed interface built on the bas of advanced ADAM modules. Results indicate that the system offers high response to pressure with reduced temperature sensitivity and, depending on the LC cell used, can be adjusted for monitoring of low hydrostatic pressures up to 6 MPa. These studies have demonstrated the feasibility of fiber optic liquid crystal colorimeter for hydrostatic pressure sensing specially dedicated to pipe- lines, mining instrumentation, and process-control technologies.

Design of a Sensor System for On-Line Monitoring of Contact Pressure in Chalcographic Printing.

PubMed

Jiménez, José Antonio; Meca, Francisco Javier; Santiso, Enrique; Martín, Pedro

2017-09-05

Chalcographic printer is the name given to a specific type of press which is used to transfer the printing of a metal-based engraved plate onto paper. The printing system consists of two rollers for pressing and carrying a metal plate onto which an engraved inked plate is placed. When the driving mechanism is operated, the pressure exerted by the rollers, also called contact pressure, allows the engraved image to be transferred into paper, thereby obtaining the final image. With the aim of ensuring the quality of the result, in terms of good and even transfer of ink, the contact pressure must be uniform. Nowadays, the strategies utilized to measure the pressure are implemented off-line, i.e., when the press machines are shut down for maintenance, which poses limitations. This paper proposes a novel sensor system aimed at monitoring the pressure exerted by the rollers on the engraved plate while chalcographic printer is operating, i.e., on-line. The purpose is two-fold: firstly, real-time monitoring reduces the number of breakdown repairs required, reduces machine downtime and reduces the number of low-quality engravings, which increases productivity and revenues; and secondly, the on-line monitoring and register of the process parameters allows the printing process to be reproducible even with changes in the environmental conditions or other factors such as the wear of the parts that constitute the mechanical system and a change in the dimensions of the printing materials. The proposed system consists of a strain gauge-based load cell and conditioning electronics to sense and treat the signals.

Design of a Sensor System for On-Line Monitoring of Contact Pressure in Chalcographic Printing

PubMed Central

Jiménez, José Antonio; Meca, Francisco Javier; Santiso, Enrique; Martín, Pedro

2017-01-01

Chalcographic printer is the name given to a specific type of press which is used to transfer the printing of a metal-based engraved plate onto paper. The printing system consists of two rollers for pressing and carrying a metal plate onto which an engraved inked plate is placed. When the driving mechanism is operated, the pressure exerted by the rollers, also called contact pressure, allows the engraved image to be transferred into paper, thereby obtaining the final image. With the aim of ensuring the quality of the result, in terms of good and even transfer of ink, the contact pressure must be uniform. Nowadays, the strategies utilized to measure the pressure are implemented off-line, i.e., when the press machines are shut down for maintenance, which poses limitations. This paper proposes a novel sensor system aimed at monitoring the pressure exerted by the rollers on the engraved plate while chalcographic printer is operating, i.e., on-line. The purpose is two-fold: firstly, real-time monitoring reduces the number of breakdown repairs required, reduces machine downtime and reduces the number of low-quality engravings, which increases productivity and revenues; and secondly, the on-line monitoring and register of the process parameters allows the printing process to be reproducible even with changes in the environmental conditions or other factors such as the wear of the parts that constitute the mechanical system and a change in the dimensions of the printing materials. The proposed system consists of a strain gauge-based load cell and conditioning electronics to sense and treat the signals. PMID:28872583

Design of the liquefied natural gas (LNG) vehicle gas cylinder filling semi-physical simulation training and assessment system

NASA Astrophysics Data System (ADS)

Gao, Jie; Zheng, Jianrong; Zhao, Yinghui

2017-08-01

With the rapid development of LNG vehicle in China, the operator's training and assessment of the operating skills cannot operate on material objects, because of Vehicle Gas Cylinder's high pressure, flammable and explosive characteristics. LNG Vehicle Gas Cylinder's filling simulation system with semi-physical simulation technology presents the overall design and procedures of the simulation system, and elaborates the realization of the practical analog machine, data acquisition and control system and the computer software, and introduces the design process of equipment simulation model in detail. According to the designed assessment system of the Vehicle Gas Cylinder, it can obtain the operation on the actual cylinder filling and visual effects for the operator, and automatically record operation, the results of real operation with its software, and achieve the operators' training and assessment of operating skills on mobile special equipment.

High Pressure and Temperature Effects in Polymers

NASA Astrophysics Data System (ADS)

Bucknall, David; Arrighi, Valeria; Johnston, Kim; Condie, Iain

Elastomers are widely exploited as the basis for seals in gas and fluid pipelines. The underlying behaviour of these elastomer at the high pressure, elevated temperatures they experience in operation is poorly understood. Consequently, the duty cycle of these materials is often deliberately limited to a few hours, and in order to prevent failure, production is stopped in order to change the seals in critical joints. The result is significant time lost due to bringing down production to change the seals as well as knock on financial costs. In order to address the fundamental nature of the elastomers at their intended operating conditions, we are studying the gas permeation behaviour of hydrogenated natural butyl rubber (HNBR) and fluorinated elastomers (FKM) at a high pressure and elevated temperature. We have developed a pressure system that permits gas permeation studies at gas pressures of up to 5000 psi and operating temperatures up to 150° C. In this paper, we will discuss the nature of the permeation behaviour at these extreme operating conditions, and how this relates to the changes in the polymer structure. We will also discuss the use of graphene-polymer thin layer coatings to modify the gas permeation behaviour of the elastomers.

The conceptual design of high temporal resolution HCN interferometry for atmospheric pressure air plasmas

NASA Astrophysics Data System (ADS)

Zhang, J. B.; Liu, H. Q.; Jie, Y. X.; Wei, X. C.; Hu, L. Q.

2018-01-01

A heterodyne interferometer operating at the frequency f = 890 GHz has been designed for measuring the electron density of atmospheric pressure air plasmas, it's density range is from 1015 to 3×1019 m-3 and the pressure range is from 1 Pa to 20 kPa. The system is configured as a Mach\

Development of Clinically Relevant Implantable Pressure Sensors: Perspectives and Challenges

PubMed Central

Clausen, Ingelin; Glott, Thomas

2014-01-01

This review describes different aspects to consider when developing implantable pressure sensor systems. Measurement of pressure is in general highly important in clinical practice and medical research. Due to the small size, light weight and low energy consumption Micro Electro Mechanical Systems (MEMS) technology represents new possibilities for monitoring of physiological parameters inside the human body. Development of clinical relevant sensors requires close collaboration between technological experts and medical clinicians. Site of operation, size restrictions, patient safety, and required measurement range and resolution, are only some conditions that must be taken into account. An implantable device has to operate under very hostile conditions. Long-term in vivo pressure measurements are particularly demanding because the pressure sensitive part of the sensor must be in direct or indirect physical contact with the medium for which we want to detect the pressure. New sensor packaging concepts are demanded and must be developed through combined effort between scientists in MEMS technology, material science, and biology. Before launching a new medical device on the market, clinical studies must be performed. Regulatory documents and international standards set the premises for how such studies shall be conducted and reported. PMID:25248071

Development of clinically relevant implantable pressure sensors: perspectives and challenges.

PubMed

Clausen, Ingelin; Glott, Thomas

2014-09-22

This review describes different aspects to consider when developing implantable pressure sensor systems. Measurement of pressure is in general highly important in clinical practice and medical research. Due to the small size, light weight and low energy consumption Micro Electro Mechanical Systems (MEMS) technology represents new possibilities for monitoring of physiological parameters inside the human body. Development of clinical relevant sensors requires close collaboration between technological experts and medical clinicians.  Site of operation, size restrictions, patient safety, and required measurement range and resolution, are only some conditions that must be taken into account. An implantable device has to operate under very hostile conditions. Long-term in vivo pressure measurements are particularly demanding because the pressure sensitive part of the sensor must be in direct or indirect physical contact with the medium for which we want to detect the pressure. New sensor packaging concepts are demanded and must be developed through combined effort between scientists in MEMS technology, material science, and biology. Before launching a new medical device on the market, clinical studies must be performed. Regulatory documents and international standards set the premises for how such studies shall be conducted and reported.

Factors defining value and direction of thermal pressure between the mine shafts and impact of the general mine natural draught on ventilation process of underground mining companies

NASA Astrophysics Data System (ADS)

Nikolaev, A. V.; Alymenko, N. I.; Kamenskikh, A. A.; Alymenko, D. N.; Nikolaev, V. A.; Petrov, A. I.

2017-10-01

The article specifies measuring data of air parameters and its volume flow in the shafts and on the surface, collected in BKPRU-2 (Berezniki potash plant and mine 2) («Uralkali» PJSC) in normal operation mode, after shutdown of the main mine fan (GVU) and within several hours. As a result of the test it has been established that thermal pressure between the mine shafts is active continuously regardless of the GVU operation mode or other draught sources. Also it has been discovered that depth of the mine shafts has no impact on thermal pressure value. By the same difference of shaft elevation marks and parameters of outer air between the shafts, by their different depth, thermal pressure of the same value will be active. Value of the general mine natural draught defined as an algebraic sum of thermal pressure values between the shafts depends only on the difference of temperature and pressure of outer air and air in the shaft bottoms on condition of shutdown of the air handling system (unit-heaters, air conditioning systems).

Enhancement of Arterial Pressure Pulsatility by Controlling Continuous-Flow Left Ventricular Assist Device Flow Rate in Mock Circulatory System.

PubMed

Bozkurt, Selim; van de Vosse, Frans N; Rutten, Marcel C M

Continuous-flow left ventricular assist devices (CF-LVADs) generally operate at a constant speed, which reduces pulsatility in the arteries and may lead to complications such as functional changes in the vascular system, gastrointestinal bleeding, or both. The purpose of this study is to increase the arterial pulse pressure and pulsatility by controlling the CF-LVAD flow rate. A MicroMed DeBakey pump was used as the CF-LVAD. A model simulating the flow rate through the aortic valve was used as a reference model to drive the pump. A mock circulation containing two synchronized servomotor-operated piston pumps acting as left and right ventricles was used as a circulatory system. Proportional-integral control was used as the control method. First, the CF-LVAD was operated at a constant speed. With pulsatile-speed CF-LVAD assistance, the pump was driven such that the same mean pump output was generated. Continuous and pulsatile-speed CF-LVAD assistance provided the same mean arterial pressure and flow rate, while the index of pulsatility increased significantly for both arterial pressure and pump flow rate signals under pulsatile speed pump support. This study shows the possibility of improving the pulsatility of CF-LVAD support by regulating pump speed over a cardiac cycle without reducing the overall level of support.

Putting Safety First in the Sky

NASA Technical Reports Server (NTRS)

2003-01-01

As a result of technology developed at NASA s Kennedy Space Center, pilots now have a hand-held personal safety device to warn them of potentially dangerous or deteriorating cabin pressure altitude conditions before hypoxia becomes a threat. The Personal Cabin Pressure Altitude Monitor and Warning System monitors cabin pressure to determine when supplemental oxygen should be used according to Federal Aviation Regulations. The device benefits both pressurized and nonpressurized aircraft operations - warning pressurized aircraft when the required safe cabin pressure altitude is compromised, and reminding nonpressurized aircraft when supplemental oxygen is needed.

Long life reference electrode

DOEpatents

Yonco, R.M.; Nagy, Z.

1987-07-30

An external, reference electrode is provided for long term use with a high temperature, high pressure system. The electrode is arranged in a vertical, electrically insulative tube with an upper portion serving as an electrolyte reservoir and a lower portion in electrolytic communication with the system to be monitored. The lower end portion includes a flow restriction such as a porous plug to limit the electrolyte release into the system. A piston equalized to the system pressure is fitted into the upper portion of the tube to impart a small incremental pressure to the electrolyte. The piston is selected of suitable size and weight to cause only a slight flow of electrolyte through the porous plug into the high pressure system. This prevents contamination of the electrolyte but is of such small flow rate that operating intervals of a month or more can be achieved. 2 figs.

Proportional assist ventilation system based on proportional solenoid valve control.

PubMed

Lua, A C; Shi, K C; Chua, L P

2001-07-01

A new proportional assist ventilation (PAV) method using a proportional solenoid valve (PSV) to control air supply to patients suffering from respiratory disabilities, was studied. The outlet flow and pressure from the proportional solenoid valve at various air supply pressures were tested and proven to be suitable for pressure and flow control in a PAV system. In vitro tests using a breathing simulator, which has been proven to possess the general characteristics of human respiratory system in spontaneous breathing tests, were conducted and the results demonstrated the viability of this PAV system in normalizing the breathing patterns of patients with abnormally high resistances and elastances as well as neuromuscular weaknesses. With a back-up safety mechanism incorporated in the control program, pressure "run-away" can be effectively prevented and safe operation of the system can be guaranteed.

Long life reference electrode

DOEpatents

Yonco, R.M.; Nagy, Z.

1989-04-04

An external, reference electrode is provided for long term use with a high temperature, high pressure system. The electrode is arranged in a vertical, electrically insulative tube with an upper portion serving as an electrolyte reservoir and a lower portion in electrolytic communication with the system to be monitored. The lower end portion includes a flow restriction such as a porous plug to limit the electrolyte release into the system. A piston equalized to the system pressure is fitted into the upper portion of the tube to impart a small incremental pressure to the electrolyte. The piston is selected of suitable size and weight to cause only a slight flow of electrolyte through the porous plug into the high pressure system. This prevents contamination of the electrolyte but is of such small flow rate that operating intervals of a month or more can be achieved. 2 figs.

Long life reference electrode

DOEpatents

Yonco, Robert M.; Nagy, Zoltan

1989-01-01

An external, reference electrode is provided for long term use with a high temperature, high pressure system. The electrode is arranged in a vertical, electrically insulative tube with an upper portion serving as an electrolyte reservior and a lower portion in electrolytic communication with the system to be monitored. The lower end portion includes a flow restriction such as a porous plug to limit the electrolyte release into the system. A piston equalized to the system pressure is fitted into the upper portion of the tube to impart a small incremental pressure to the electrolyte. The piston is selected of suitable size and weight to cause only a slight flow of electrolyte through the porous plug into the high pressure system. This prevents contamination of the electrolyte but is of such small flow rate that operating intervals of a month or more can be achieved.

Flowmeter evaluation for on-orbit operations

NASA Technical Reports Server (NTRS)

Baird, R. S.

1988-01-01

Various flowmetering concepts were flow tested to characterize the relative capabilities and limitations for on-orbit fluid-transfer operations. Performance results and basic operating principles of each flowmetering concept tested are summarized, and basic considerations required to select the best flowmeter(s) for fluid system application are discussed. Concepts tested were clamp-on ultrasonic, area averaging ultrasonic, offset ultrasonic, coriolis mass, vortex shedding, universal venturi tube, turbine, bearingless turbine, turbine/turbine differential-pressure hybrid, dragbody, and dragbody/turbine hybrid flowmeters. Fluid system flowmeter selection considerations discussed are flowmeter performance, fluid operating conditions, systems operating environments, flowmeter packaging, flowmeter maintenance, and flowmeter technology. No one flowmetering concept tested was shown to be best for all on-orbit fluid systems.

Apparatus for gas sorption measurement with integrated gas composition measurement device and gas mixing

DOEpatents

Micklash. II, Kenneth James; Dutton, Justin James; Kaye, Steven

2014-06-03

An apparatus for testing of multiple material samples includes a gas delivery control system operatively connectable to the multiple material samples and configured to provide gas to the multiple material samples. Both a gas composition measurement device and pressure measurement devices are included in the apparatus. The apparatus includes multiple selectively openable and closable valves and a series of conduits configured to selectively connect the multiple material samples individually to the gas composition device and the pressure measurement devices by operation of the valves. A mixing system is selectively connectable to the series of conduits and is operable to cause forced mixing of the gas within the series of conduits to achieve a predetermined uniformity of gas composition within the series of conduits and passages.

Extravehicular mobility unit subcritical liquid oxygen storage and supply system

NASA Technical Reports Server (NTRS)

Anderson, John; Martin, Timothy; Hodgson, ED

1992-01-01

The storage of life support oxygen in the Extravehicular Mobility Unit in the liquid state offers some advantages over the current method of storing the oxygen as a high pressure gas. Storage volume is reduced because of the increased density associated with liquid. The lower storage and operating pressures also reduce the potential for leakage or bursting of the storage tank. The potential for combustion resulting from adiabatic combustion of the gas within lines and components is substantially reduced. Design constraints on components are also relaxed due to the lower system pressures. A design study was performed to determine the requirements for a liquid storage system and prepare a conceptual design. The study involved four tasks. The first was to identify system operating requirements that influence or direct the design of the system. The second was to define candidate storage system concepts that could possibly satisfy the requirements. An evaluation and comparison of the candidate concepts was conducted in the third task. The fourth task was devoted to preparing a conceptual design of the recommended storage system and to evaluate concerns with integration of the concept into the EMU. The results are presented.

Energy efficient fluid powered linear actuator with variable area

DOEpatents

Lind, Randall F.; Love, Lonnie J.

2016-09-13

Hydraulic actuation systems having variable displacements and energy recovery capabilities include cylinders with pistons disposed inside of barrels. When operating in energy consuming modes, high speed valves pressurize extension chambers or retraction chambers to provide enough force to meet or counteract an opposite load force. When operating in energy recovery modes, high speed valves return a working fluid from extension chambers or retraction chambers, which are pressurized by a load, to an accumulator for later use.

Fuel cell system shutdown with anode pressure control

DOEpatents

Clingerman, Bruce J.; Doan, Tien M.; Keskula, Donald H.

2002-01-01

A venting methodology and pressure sensing and vent valving arrangement for monitoring anode bypass valve operating during the normal shutdown of a fuel cell apparatus of the type used in vehicle propulsion systems. During a normal shutdown routine, the pressure differential between the anode inlet and anode outlet is monitored in real time in a period corresponding to the normal closing speed of the anode bypass valve and the pressure differential at the end of the closing cycle of the anode bypass valve is compared to the pressure differential at the beginning of the closing cycle. If the difference in pressure differential at the beginning and end of the anode bypass closing cycle indicates that the anode bypass valve has not properly closed, a system controller switches from a normal shutdown mode to a rapid shutdown mode in which the anode inlet is instantaneously vented by rapid vents.

Establishing operational stability--developing human infrastructure.

PubMed

Gomez, Max A; Byers, Ernest J; Stingley, Preston; Sheridan, Robert M; Hirsch, Joshua A

2010-12-01

Over the past year, Toyota has come under harsh scrutiny as a result of several recalls. These well publicized mishaps have not only done damage to Toyota's otherwise sterling reputation for quality but have also called into question the assertions from a phalanx of followers that Toyota's production system (generically referred to as TPS or Lean) is the best method by which to structure one's systems of operation. In this article, we discuss how Toyota, faced with the pressure to grow its business, did not appropriately cadence this growth with the continued development and maintenance of the process capabilities (vis a vis the development of human infrastructure) needed to adequately support that growth. We draw parallels between the pressure Toyota faced to grow its business and the pressure neurointerventional practices face to grow theirs, and offer a methodology to support that growth without sacrificing quality.

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

Wichman, K.; Tsao, J.; Mayfield, M.

The regulatory application of leak before break (LBB) for operating and advanced reactors in the U.S. is described. The U.S. Nuclear Regulatory Commission (NRC) has approved the application of LBB for six piping systems in operating reactors: reactor coolant system primary loop piping, pressurizer surge, safety injection accumulator, residual heat removal, safety injection, and reactor coolant loop bypass. The LBB concept has also been applied in the design of advanced light water reactors. LBB applications, and regulatory considerations, for pressurized water reactors and advanced light water reactors are summarized in this paper. Technology development for LBB performed by the NRCmore » and the International Piping Integrity Research Group is also briefly summarized.« less

An Approach to Detect and Mitigate Ice Particle Accretion in Aircraft Engine Compression Systems

NASA Technical Reports Server (NTRS)

May, Ryan D.; Guo, Ten-Huei; Simon, Donald L.

2013-01-01

The accretion of ice in the compression system of commercial gas turbine engines operating in high ice water content conditions is a safety issue being studied by the aviation sector. While most of the research focuses on the underlying physics of ice accretion and the meteorological conditions in which accretion can occur, a systems-level perspective on the topic lends itself to potential near-term operational improvements. This work focuses on developing an accurate and reliable algorithm for detecting the accretion of ice in the low pressure compressor of a generic 40,000 lbf thrust class engine. The algorithm uses only the two shaft speed sensors and works regardless of engine age, operating condition, and power level. In a 10,000-case Monte Carlo simulation, the detection approach was found to have excellent capability at determining ice accretion from sensor noise with detection occurring when ice blocks an average of 6.8 percent of the low pressure compressor area. Finally, an initial study highlights a potential mitigation strategy that uses the existing engine actuators to raise the temperature in the low pressure compressor in an effort to reduce the rate at which ice accretes.

An Approach to Detect and Mitigate Ice Particle Accretion in Aircraft Engine Compression Systems

NASA Technical Reports Server (NTRS)

May, Ryan D.; Guo, Ten-Huei; Simon, Donald L.

2013-01-01

The accretion of ice in the compression system of commercial gas turbine engines operating in high ice water content conditions is a safety issue being studied by the aviation sector. While most of the research focuses on the underlying physics of ice accretion and the meteorological conditions in which accretion can occur, a systems-level perspective on the topic lends itself to potential near-term operational improvements. This work focuses on developing an accurate and reliable algorithm for detecting the accretion of ice in the low pressure compressor of a generic 40,000 lbf thrust class engine. The algorithm uses only the two shaft speed sensors and works regardless of engine age, operating condition, and power level. In a 10,000-case Monte Carlo simulation, the detection approach was found to have excellent capability at determining ice accretion from sensor noise with detection occurring when ice blocks an average of 6.8% of the low pressure compressor area. Finally, an initial study highlights a potential mitigation strategy that uses the existing engine actuators to raise the temperature in the low pressure compressor in an effort to reduce the rate at which ice accretes.

A Systems-Level Perspective on Engine Ice Accretion

NASA Technical Reports Server (NTRS)

May, Ryan D.; Guo, Ten-Huei; Simon, Donald L.

2013-01-01

The accretion of ice in the compression system of commercial gas turbine engines operating in high ice water content conditions is a safety issue being studied by the aviation sector. While most of the research focuses on the underlying physics of ice accretion and the meteorological conditions in which accretion can occur, a systems-level perspective on the topic lends itself to potential near-term operational improvements. This work focuses on developing an accurate and reliable algorithm for detecting the accretion of ice in the low pressure compressor of a generic 40,000 lbf thrust class engine. The algorithm uses only the two shaft speed sensors and works regardless of engine age, operating condition, and power level. In a 10,000-case Monte Carlo simulation, the detection approach was found to have excellent capability at determining ice accretion from sensor noise with detection occurring when ice blocks an average of 6.8% of the low pressure compressor area. Finally, an initial study highlights a potential mitigation strategy that uses the existing engine actuators to raise the temperature in the low pressure compressor in an effort to reduce the rate at which ice accretes.

Radiation-transparent windows, method for imaging fluid transfers

DOEpatents

Shu, Deming [Darien, IL; Wang, Jin [Burr Ridge, IL

2011-07-26

A thin, x-ray-transparent window system for environmental chambers involving pneumatic pressures above 40 bar is presented. The window allows for x-ray access to such phenomena as fuel sprays injected into a pressurized chamber that mimics realistic internal combustion engine cylinder operating conditions.

The balloon and the airship technological heritage

NASA Technical Reports Server (NTRS)

Mayer, N. J.

1981-01-01

The balloon and the airship are discussed with emphasis on the identification of commonalities and distinctions. The aerostat technology behind the shape and structure of the vehicles is reviewed, including a discussion of structural weight, internal pressure, buckling, and the development of a stable tethered balloon system. Proper materials for the envelope are considered, taking elongation and stress into account, and flight operation and future developments are reviewed. Airships and tethered balloons which are designed to carry high operating pressure with low gas loss characteristics are found to share similar problems in low speed flight operations, while possessing interchangeable technologies.

Ice Crystal Icing Engine Testing in the NASA Glenn Research Center's Propulsion Systems Laboratory: Altitude Investigation

NASA Technical Reports Server (NTRS)

Oliver, Michael J.

2014-01-01

The National Aeronautics and Space Administration (NASA) conducted a full scale ice crystal icing turbofan engine test using an obsolete Allied Signal ALF502-R5 engine in the Propulsion Systems Laboratory (PSL) at NASA Glenn Research Center. The test article used was the exact engine that experienced a loss of power event after the ingestion of ice crystals while operating at high altitude during a 1997 Honeywell flight test campaign investigating the turbofan engine ice crystal icing phenomena. The test plan included test points conducted at the known flight test campaign field event pressure altitude and at various pressure altitudes ranging from low to high throughout the engine operating envelope. The test article experienced a loss of power event at each of the altitudes tested. For each pressure altitude test point conducted the ambient static temperature was predicted using a NASA engine icing risk computer model for the given ambient static pressure while maintaining the engine speed.

Optimal pressure regulation of the pneumatic ventricular assist device with bellows-type driver.

PubMed

Lee, Jung Joo; Kim, Bum Soo; Choi, Jaesoon; Choi, Hyuk; Ahn, Chi Bum; Nam, Kyoung Won; Jeong, Gi Seok; Lim, Choon Hak; Son, Ho Sung; Sun, Kyung

2009-08-01

The bellows-type pneumatic ventricular assist device (VAD) generates pneumatic pressure with compression of bellows instead of using an air compressor. This VAD driver has a small volume that is suitable for portable devices. However, improper pneumatic pressure setup can not only cause a lack of adequate flow generation, but also cause durability problems. In this study, a pneumatic pressure regulation system for optimal operation of the bellows-type VAD has been developed. The optimal pneumatic pressure conditions according to various afterload conditions aiming for optimal flow rates were investigated, and an afterload estimation algorithm was developed. The developed regulation system, which consists of a pressure sensor and a two-way solenoid valve, estimates the current afterload and regulates the pneumatic pressure to the optimal point for the current afterload condition. Experiments were performed in a mock circulation system. The afterload estimation algorithm showed sufficient performance with the standard deviation of error, 8.8 mm Hg. The flow rate could be stably regulated with a developed system under various afterload conditions. The shortcoming of a bellows-type VAD could be handled with this simple pressure regulation system.

14 CFR 25.1107 - Inter-coolers and after-coolers.

Code of Federal Regulations, 2010 CFR

2010-01-01

... AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES Powerplant Induction System § 25.1107 Inter..., inertia, and air pressure load to which it would be subjected in operation. Exhaust System ...

High Pressure Earth Storable Rocket Technology Program: Basic Program

NASA Technical Reports Server (NTRS)

Chazen, M. L.; Sicher, D.; Huang, D.; Mueller, T.

1995-01-01

The HIPES Program was conducted for NASA-LeRC by TRW. The Basic Program consisted of system studies, design of testbed engine, fabrication and testing of engine. Studies of both pressure-fed and pump-fed systems were investigated for N2O4 and both MMH and N2H4 fuels with the result that N2H4 provides the maximum payload for all satellites over MMH. The higher pressure engine offers improved performance with smaller envelope and associated weight savings. Pump-fed systems offer maximum payload for large and medium weight satellites while pressure-fed systems offer maximum payload for small light weight satellites. The major benefits of HIPES are high performance within a confined length maximizing payload for lightsats which are length (volume) constrained. Three types of thrust chambers were evaluated -- Copper heatsink at 400, 500 and 600 psia chamber pressures for performance/thermal; water cooled to determine heat absorbed to predict rhenium engine operation; and rhenium to validate the concept. The HIPES engine demonstrated very high performance at 50 lbf thrust (epsilon = 150) and Pc = 500 psia with both fuels: Isp = 337 sec using N2O4-N2H4 and ISP = 327.5 sec using N2O4-MMH indicating combustion efficiencies greater than 98%. A powder metallurgy rhenium engine demonstrated operation with high performance at Pc = 500 psia which indicated the viability of the concept.

High concentration biotherapeutic formulation and ultrafiltration: Part 1 pressure limits.

PubMed

Lutz, Herb; Arias, Joshua; Zou, Yu

2017-01-01

High therapeutic dosage requirements and the desire for ease of administration drive the trend to subcutaneous administration using delivery systems such as subcutaneous pumps and prefilled syringes. Because of dosage volume limits, prefilled syringe administration requires higher concentration liquid formulations, limited to about 30 cP or roughly 100-300 g L -1 for mAb's. Ultrafiltration (UF) processes are routinely used to formulate biological therapeutics. This article considers pressure constraints on the UF process that may limit its ability to achieve high final product concentrations. A system hardware analysis shows that the ultrafiltration cassette pressure drop is the major factor limiting UF systems. Additional system design recommendations are also provided. The design and performance of a new cassette with a lower feed channel flow resistance is described along with 3D modeling of feed channel pressure drop. The implications of variations in cassette flow channel resistance for scaling up and setting specifications are considered. A recommendation for a maximum pressure specification is provided. A review of viscosity data and theory shows that molecular engineering, temperature, and the use of viscosity modifying excipients including pH adjustment can be used to achieve higher concentrations. The combined use of a low pressure drop cassette with excipients further increased final concentrations by 35%. Guidance is provided on system operation to control hydraulics during final concentration. These recommendations should allow one to design and operate systems to routinely achieve the 30 cP target final viscosity capable of delivery using a pre-filled syringe. © 2016 American Institute of Chemical Engineers Biotechnol. Prog., 33:113-124, 2017. © 2016 American Institute of Chemical Engineers.

Neural Regulation of Cardiovascular Response to Exercise: Role of Central Command and Peripheral Afferents

PubMed Central

Nobrega, Antonio C. L.; O'Leary, Donal; Silva, Bruno Moreira; Piepoli, Massimo F.; Crisafulli, Antonio

2014-01-01

During dynamic exercise, mechanisms controlling the cardiovascular apparatus operate to provide adequate oxygen to fulfill metabolic demand of exercising muscles and to guarantee metabolic end-products washout. Moreover, arterial blood pressure is regulated to maintain adequate perfusion of the vital organs without excessive pressure variations. The autonomic nervous system adjustments are characterized by a parasympathetic withdrawal and a sympathetic activation. In this review, we briefly summarize neural reflexes operating during dynamic exercise. The main focus of the present review will be on the central command, the arterial baroreflex and chemoreflex, and the exercise pressure reflex. The regulation and integration of these reflexes operating during dynamic exercise and their possible role in the pathophysiology of some cardiovascular diseases are also discussed. PMID:24818143

Water cycle and its management for plant habitats at reduced pressures

NASA Technical Reports Server (NTRS)

Rygalov, Vadim Y.; Fowler, Philip A.; Wheeler, Raymond M.; Bucklin, Ray A.

2004-01-01

Experimental and mathematical models were developed for describing and testing temperature and humidity parameters for plant production in bioregenerative life support systems. A factor was included for analyzing systems operating at low (10-101.3 kPa) pressure to reduce gas leakage and structural mass (e.g., inflatable greenhouses for space application). The expected close relationship between temperature and relative humidity was observed, along with the importance of heat exchanger coil temperature and air circulation rate. The presence of plants in closed habitats results in increased water flux through the system. Changes in pressure affect gas diffusion rates and surface boundary layers, and change convective transfer capabilities and water evaporation rates. A consistent observation from studies with plants at reduced pressures is increased evapotranspiration rates, even at constant vapor pressure deficits. This suggests that plant water status is a critical factor for managing low-pressure production systems. The approach suggested should help space mission planners design artificial environments in closed habitats.

Water cycle and its management for plant habitats at reduced pressures.

PubMed

Rygalov, Vadim Y; Fowler, Philip A; Wheeler, Raymond M; Bucklin, Ray A

2004-01-01

Experimental and mathematical models were developed for describing and testing temperature and humidity parameters for plant production in bioregenerative life support systems. A factor was included for analyzing systems operating at low (10-101.3 kPa) pressure to reduce gas leakage and structural mass (e.g., inflatable greenhouses for space application). The expected close relationship between temperature and relative humidity was observed, along with the importance of heat exchanger coil temperature and air circulation rate. The presence of plants in closed habitats results in increased water flux through the system. Changes in pressure affect gas diffusion rates and surface boundary layers, and change convective transfer capabilities and water evaporation rates. A consistent observation from studies with plants at reduced pressures is increased evapotranspiration rates, even at constant vapor pressure deficits. This suggests that plant water status is a critical factor for managing low-pressure production systems. The approach suggested should help space mission planners design artificial environments in closed habitats.

78 FR 57455 - Pipeline Safety: Information Collection Activities

Federal Register 2010, 2011, 2012, 2013, 2014

2013-09-18

... ``. . . system-specific information, including pipe diameter, operating pressure, product transported, and...) must provide contact information and geospatial data on their pipeline system. This information should... Mapping System (NPMS) to support various regulatory programs, pipeline inspections, and authorized...

40 CFR 63.7525 - What are my monitoring, installation, operation, and maintenance requirements?

Code of Federal Regulations, 2010 CFR

2010-07-01

... tolerance of 1.27 centimeters of water or a transducer with a minimum tolerance of 1 percent of the pressure... use a fabric filter bag leak detection system to comply with the requirements of this subpart, you must install, calibrate, maintain, and continuously operate a bag leak detection system as specified in...

Pressure-Volume-Temperature (PVT) Gauging of an Isothermal Cryogenic Propellant Tank Pressurized with Gaseous Helium

NASA Technical Reports Server (NTRS)

VanDresar, Neil T.; Zimmerli, Gregory A.

2014-01-01

Results are presented for pressure-volume-temperature (PVT) gauging of a liquid oxygen/liquid nitrogen tank pressurized with gaseous helium that was supplied by a high-pressure cryogenic tank simulating a cold helium supply bottle on a spacecraft. The fluid inside the test tank was kept isothermal by frequent operation of a liquid circulation pump and spray system, and the propellant tank was suspended from load cells to obtain a high-accuracy reference standard for the gauging measurements. Liquid quantity gauging errors of less than 2 percent of the tank volume were obtained when quasi-steady-state conditions existed in the propellant and helium supply tanks. Accurate gauging required careful attention to, and corrections for, second-order effects of helium solubility in the liquid propellant plus differences in the propellant/helium composition and temperature in the various plumbing lines attached to the tanks. On the basis of results from a helium solubility test, a model was developed to predict the amount of helium dissolved in the liquid as a function of cumulative pump operation time. Use of this model allowed correction of the basic PVT gauging calculations and attainment of the reported gauging accuracy. This helium solubility model is system specific, but it may be adaptable to other hardware systems.

Controlling Gas-Flow Mass Ratios

NASA Technical Reports Server (NTRS)

Morris, Brian G.

1990-01-01

Proposed system automatically controls proportions of gases flowing in supply lines. Conceived for control of oxidizer-to-fuel ratio in new gaseous-propellant rocket engines. Gas-flow control system measures temperatures and pressures at various points. From data, calculates control voltages for electronic pressure regulators for oxygen and hydrogen. System includes commercially available components. Applicable to control of mass ratios in such gaseous industrial processes as chemical-vapor depostion of semiconductor materials and in automotive engines operating on compressed natural gas.

Method of air preheating for combustion power plant and systems comprising the same

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

Zhang, Wei

Disclosed herein is a heat exchanger for transferring heat between a first gas flow and a second gas flow, the heat exchanger comprising at least two sectors; a first sector that is operative to receive a combustion air stream; and a second sector that is opposed to the first sector and that is operative to receive either a reducer gas stream or an oxidizer gas stream, and a pressurized layer disposed between the first sector and the second sector; where the pressurized layer is at a higher pressure than combustion air stream, the reducer gas stream and the oxidizer gasmore » stream.« less

Evaluation of Agency Non-Code Layered Pressure Vessels (LPVs) . Volume 2; Appendices

NASA Technical Reports Server (NTRS)

Prosser, William H.

2014-01-01

In coordination with the Office of Safety and Mission Assurance and the respective Center Pressure System Managers (PSMs), the NASA Engineering and Safety Center (NESC) was requested to formulate a consensus draft proposal for the development of additional testing and analysis methods to establish the technical validity, and any limitation thereof, for the continued safe operation of facility non-code layered pressure vessels. The PSMs from each NASA Center were asked to participate as part of the assessment team by providing, collecting, and reviewing data regarding current operations of these vessels. This document contains the appendices to the main report.

Pressure Dome for High-Pressure Electrolyzer

NASA Technical Reports Server (NTRS)

Norman, Timothy; Schmitt, Edwin

2012-01-01

A high-strength, low-weight pressure vessel dome was designed specifically to house a high-pressure [2,000 psi (approx. = 13.8 MPa)] electrolyzer. In operation, the dome is filled with an inert gas pressurized to roughly 100 psi (approx. = 690 kPa) above the high, balanced pressure product oxygen and hydrogen gas streams. The inert gas acts to reduce the clamping load on electrolyzer stack tie bolts since the dome pressure acting axially inward helps offset the outward axial forces from the stack gas pressure. Likewise, radial and circumferential stresses on electrolyzer frames are minimized. Because the dome is operated at a higher pressure than the electrolyzer product gas, any external electrolyzer leak prevents oxygen or hydrogen from leaking into the dome. Instead the affected stack gas stream pressure rises detectably, thereby enabling a system shutdown. All electrical and fluid connections to the stack are made inside the pressure dome and require special plumbing and electrical dome interfaces for this to be accomplished. Further benefits of the dome are that it can act as a containment shield in the unlikely event of a catastrophic failure. Studies indicate that, for a given active area (and hence, cell ID), frame outside diameter must become ever larger to support stresses at higher operating pressures. This can lead to a large footprint and increased costs associated with thicker and/or larger diameter end-plates, tie-rods, and the frames themselves. One solution is to employ rings that fit snugly around the frame. This complicates stack assembly and is sometimes difficult to achieve in practice, as its success is strongly dependent on frame and ring tolerances, gas pressure, and operating temperature. A pressure dome permits an otherwise low-pressure stack to operate at higher pressures without growing the electrolyzer hardware. The pressure dome consists of two machined segments. An O-ring is placed in an O-ring groove in the flange of the bottom segment and is trapped by the flange on the top dome segment when these components are bolted together with high-strength bolts. The pressure dome has several unique features. It is made (to ASME Pressure Vessel guidelines) in a high-strength aluminum alloy with the strength of stainless steel and the weight benefits of aluminum. The flange of the upper dome portion contains specially machined flats for mounting the dome, and other flats dedicated to the special feedthroughs for electrical connections. A pressure dome can be increased in length to house larger stacks (more cells) of the same diameter with the simple addition of a cylindrical segment. To aid in dome assembly, two stainless steel rings are employed. One is used beneath the heads of the high-strength bolts in lieu of individual hardened washers, and another is used instead of individual nuts. Like electrolyzers could be operated at low or high pressures simply by operating the electrolyzer outside or inside a pressurized dome.

Quantification of peripheral and central blood pressure variability using a time-frequency method.

PubMed

Kouchaki, Z; Butlin, M; Qasem, A; Avolio, A P

2016-08-01

Systolic blood pressure variability (BPV) is associated with cardiovascular events. As the beat-to-beat variation of blood pressure is due to interaction of several cardiovascular control systems operating with different response times, assessment of BPV by spectral analysis using the continuous measurement of arterial pressure in the finger is used to differentiate the contribution of these systems in regulating blood pressure. However, as baroreceptors are centrally located, this study considered applying a continuous aortic pressure signal estimated noninvasively from finger pressure for assessment of systolic BPV by a time-frequency method using Short Time Fourier Transform (STFT). The average ratio of low frequency and high frequency power band (LF PB /HF PB ) was computed by time-frequency decomposition of peripheral systolic pressure (pSBP) and derived central aortic systolic blood pressure (cSBP) in 30 healthy subjects (25-62 years) as a marker of balance between cardiovascular control systems contributing in low and high frequency blood pressure variability. The results showed that the BPV assessed from finger pressure (pBPV) overestimated the BPV values compared to that assessed from central aortic pressure (cBPV) for identical cardiac cycles (P<;0.001), with the overestimation being greater at higher power.

Fluid dynamic modelling of renal pelvic pressure during endoscopic stone removal

NASA Astrophysics Data System (ADS)

Oratis, Alexandros; Subasic, John; Bird, James; Eisner, Brian

2015-11-01

Endoscopic kidney stone removal procedures are known to increase internal pressure in the renal pelvis, the kidney's urinary collecting system. High renal pelvic pressure incites systemic absorption of irrigation fluid, which can increase the risk of postoperative fever and sepsis or the unwanted absorption of electrolytes. Urologists choose the appropriate surgical procedure based on patient history and kidney stone size. However, no study has been conducted to compare the pressure profiles of each procedure, nor is there a precise sense of how the renal pelvic pressure scales with various operational parameters. Here we develop physical models for the flow rates and renal pelvic pressure for various procedures. We show that the results of our models are consistent with existing urological data on each procedure and that the models can predict pressure profiles where data is unavailable.

Structural Integrity of Gas-Filled Composite Overwrapped Pressure Vessels Subjected to Orbital Debris Impact

NASA Astrophysics Data System (ADS)

Telichev, Igor; Cherniaev, Aleksandr

Gas-filled pressure vessels are extensively used in spacecraft onboard systems. During operation on the orbit they exposed to the space debris environment. Due to high energies they contain, pressure vessels have been recognized as the most critical spacecraft components requiring protection from orbital debris impact. Major type of pressurized containers currently used in spacecraft onboard systems is composite overwrapped pressure vessels (COPVs) manufactured by filament winding. In the present work we analyze the structural integrity of vessels of this kind in case of orbital debris impact at velocities ranging from 2 to 10 km/s. Influence of such parameters as projectile energy, shielding standoff, internal pressure and filament winding pattern on COPVs structural integrity has been investigated by means of numerical and physical experiments.

A novel solar bi-ejector refrigeration system and the performance of the added injector with different structures and operation parameters

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

Wang, Fei; Shen, Shengqiang

2009-12-15

A novel solar bi-ejector refrigeration system was investigated, whose difference compared to the traditional system is that the circulation pump is replaced by a thermal injector. The new system works more stably and needs less maintenance work than the old one, and the whole system can more fully utilize the solar energy. The mathematical models for calculating the performance of the injector and the whole solar refrigeration system were established. The pressure rise performance of injector under different structure and operation parameters and the performance of solar bi-ejector refrigeration system were studied with R123. The results show that the dischargedmore » pressure of injector is affected by structure dimensions of injector and operation conditions. With increasing generation temperature, the entrainment ratio of ejector becomes better while that of injector becomes worse and the overall thermal efficiency of the solar bi-ejector refrigeration system first increases and then decreases with an optimum value of 0.132 at generation temperature of 105 C, condensation temperature of 35 C and evaporation temperature of 10 C. (author)« less

Preliminary Engineering Design Package for the Basin A Neck Groundwater Intercept and Treatment System Interim Response Action

DTIC Science & Technology

1989-02-01

INDICATOR pPOST-FILTERED VITER RPUESIC POST-FILTRATION POLYMER SOLUTION MCUUM BREAKER FILTRATION POLYMER D*+RENTALkL PRESSURE SWITCH FEED PUMPS POLYMER...differential pressure switch signals the need for backwash of the operating filter. At this time, flow is S automatically switched to the standby filter...filter is undergoing backwash or on standby. High differential pressure across the filter bed, as sensed by a differential pressure switch , signals

Mobile communication devices causing interference in invasive and noninvasive ventilators.

PubMed

Dang, Bao P; Nel, Pierre R; Gjevre, John A

2007-06-01

The aim of this study was to assess if common mobile communication systems would cause significant interference on mechanical ventilation devices and at what distances would such interference occur. We tested all the invasive and noninvasive ventilatory devices used within our region. This consisted of 2 adult mechanical ventilators, 1 portable ventilator, 2 pediatric ventilators, and 2 noninvasive positive pressure ventilatory devices. We operated the mobile devices from the 2 cellular communication systems (digital) and 1 2-way radio system used in our province at varying distances from the ventilators and looked at any interference they created. We tested the 2-way radio system, which had a fixed operation power output of 3.0 watts, the Global Systems for Mobile Communication cellular system, which had a maximum power output of 2.0 watts and the Time Division Multiple Access cellular system, which had a maximum power output of 0.2 watts on our ventilators. The ventilators were ventilating a plastic lung at fixed settings. The mobile communication devices were tested at varying distances starting at zero meter from the ventilator and in all operation modes. The 2-way radio caused the most interference on some of the ventilators, but the maximum distance of interference was 1.0 m. The Global Systems for Mobile Communication system caused significant interference only at 0 m and minor interference at 0.5 m on only 1 ventilator. The Time Division Multiple Access system caused no interference at all. Significant interference consisted of a dramatic rise and fluctuation of the respiratory rate, pressure, and positive end-expiratory pressure of the ventilators with no normalization when the mobile device was removed. From our experiment on our ventilators with the communication systems used in our province, we conclude that mobile communication devices such as cellular phones and 2-way radios are safe and cause no interference unless operated at very close distances of less than 1 meter.

Ignition of PTFE-lined flexible hoses by rapid pressurization with oxygen

NASA Technical Reports Server (NTRS)

Janoff, Dwight; Bamford, Larry J.; Newton, Barry E.; Bryan, Coleman J.

1989-01-01

A high-volume pneumatic-impact system has been used to test PTFE-lined stainless steel braided hoses, in order to characterize the roles played in the mechanism of oxygen-induced ignition by impact pressure, pressurization rate, and upstream and downstream volumes of the hose. Ignitions are noted to have occurred at impact pressures well below the working pressure of the hoses, as well as at pressurization rates easily obtainable through manual operation of valves. The use of stainless steel hardlines downstream of the hose prevented ignitions at all pressures and pressurization rates; internal observations have shown evidence of shock ionization in the oxygen prior to ignition.

Ignition of PTFE-lined flexible hoses by rapid pressurization with oxygen

NASA Astrophysics Data System (ADS)

Janoff, Dwight; Bamford, Larry J.; Newton, Barry E.; Bryan, Coleman J.

A high-volume pneumatic-impact system has been used to test PTFE-lined stainless steel braided hoses, in order to characterize the roles played in the mechanism of oxygen-induced ignition by impact pressure, pressurization rate, and upstream and downstream volumes of the hose. Ignitions are noted to have occurred at impact pressures well below the working pressure of the hoses, as well as at pressurization rates easily obtainable through manual operation of valves. The use of stainless steel hardlines downstream of the hose prevented ignitions at all pressures and pressurization rates; internal observations have shown evidence of shock ionization in the oxygen prior to ignition.

An occultation satellite system for determining pressure levels in the atmosphere

NASA Technical Reports Server (NTRS)

Ungar, S. G.; Lusignan, B. B.

1972-01-01

An operational two-satellite microwave occultation system will establish a pressure reference level to be used in fixing the temperature-pressure profile generated by the SIRS infrared sensor as a function of altitude. In the final error analysis, simulated data for the SIRS sensor were used to test the performance of the occultation system. The results of this analysis indicate that the occultation system is capable of measuring the altitude of the 300-mb level to within 24 mrms, given a maximum error of 2 K in the input temperature profile. The effects of water vapor can be corrected by suitable climatological profiles, and improvements in the accuracy of the SIRS instrument should yield additional improvements in the performance of the occultation system.

Application of an automation system and a supervisory control and data acquisition (SCADA) system for the optimal operation of a membrane adsorption hybrid system.

PubMed

Smith, P J; Vigneswaran, S; Ngo, H H; Nguyen, H T; Ben-Aim, R

2006-01-01

The application of automation and supervisory control and data acquisition (SCADA) systems to municipal water and wastewater treatment plants is rapidly increasing. However, the application of these systems is less frequent in the research and development phases of emerging treatment technologies used in these industries. This study involved the implementation of automation and a SCADA system to the submerged membrane adsorption hybrid system for use in a semi-pilot scale research project. An incremental approach was used in the development of the automation and SCADA systems, leading to the development of two new control systems. The first system developed involved closed loop control of the backwash initiation, based upon a pressure increase, leading to productivity improvements as the backwash is only activated when required, not at a fixed time. This system resulted in a 40% reduction in the number of backwashes required and also enabled optimised operations under unsteady concentrations of wastewater. The second system developed involved closed loop control of the backwash duration, whereby the backwash was terminated when the pressure reached a steady state. This system resulted in a reduction of the duration of the backwash of up to 25% and enabled optimised operations as the foulant build-up within the reactor increased.

Circumferential distortion modeling of the TF30-P-3 compression system

NASA Technical Reports Server (NTRS)

Mazzawy, R. S.; Banks, G. A.

1977-01-01

Circumferential inlet pressure and temperature distortion testing of the TF30 P-3 turbofan engine was conducted. The compressor system at the test conditions run was modelled according to a multiple segment parallel compressor model. Aspects of engine operation and distortion configuration modelled include the effects of compressor bleeds, relative pressure-temperature distortion alignment and circumferential distortion extent. Model predictions for limiting distortion amplitudes and flow distributions within the compression system were compared with test results in order to evaluate predicted trends. Relatively good agreement was obtained. The model also identified the low pressure compressor as the stall-initiating component, which was in agreement with the data.

Energy efficient fluid powered linear actuator with variable area and concentric chambers

DOEpatents

Lind, Randall F.; Love, Lonnie J.

2016-11-15

Hydraulic actuation systems having concentric chambers, variable displacements and energy recovery capabilities include cylinders with pistons disposed inside of barrels. When operating in energy consuming modes, high speed valves pressurize extension chambers or retraction chambers to provide enough force to meet or counteract an opposite load force. When operating in energy recovery modes, high speed valves return a working fluid from extension chambers or retraction chambers, which are pressurized by a load, to an accumulator for later use.

Compressed air energy storage system

DOEpatents

Ahrens, Frederick W.; Kartsounes, George T.

1981-01-01

An internal combustion reciprocating engine is operable as a compressor during slack demand periods utilizing excess power from a power grid to charge air into an air storage reservoir and as an expander during peak demand periods to feed power into the power grid utilizing air obtained from the air storage reservoir together with combustible fuel. Preferably the internal combustion reciprocating engine is operated at high pressure and a low pressure turbine and compressor are also employed for air compression and power generation.

ASRDI Oxygen Technological Survey. Volume 9; Oxygen Systems Engineering Review

NASA Technical Reports Server (NTRS)

Schmidt, H. W.; Forney, D. E.

1975-01-01

The design and safe operation of O2 systems at high pressures and temperatures are discussed. Data cover O2 reactivity with system materials, environmental limits, flow rate, contamination, and physical and chemical stresses of materials.

Absorption machine with desorber-resorber

DOEpatents

Biermann, Wendell J.

1985-01-01

An absorption refrigeration system utilizing a low temperature desorber and intermediate temperature resorber. The system operates at three temperatures and three pressures to increase the efficiency of the system and is capable of utilizing a lower generator temperature than previously used.

30 CFR 250.433 - What are the diverter actuation and testing requirements?

Code of Federal Regulations, 2010 CFR

2010-07-01

... OFFSHORE OIL AND GAS AND SULPHUR OPERATIONS IN THE OUTER CONTINENTAL SHELF Oil and Gas Drilling Operations...-control systems and control stations. You must also flow-test the vent lines. (a) For drilling operations... must conduct subsequent pressure tests within 7 days after the previous test. (b) For floating drilling...

40 CFR 62.14700 - What records must I keep?

Code of Federal Regulations, 2010 CFR

2010-07-01

... charge rates. (2) Liquor flow rate to the wet scrubber inlet every 15 minutes of operation, as applicable. (3) Pressure drop across the wet scrubber system every 15 minutes of operation or amperage to the wet scrubber every 15 minutes of operation, as applicable. (4) Liquor pH as introduced to the wet scrubber...

40 CFR 62.14700 - What records must I keep?

Code of Federal Regulations, 2011 CFR

2011-07-01

... charge rates. (2) Liquor flow rate to the wet scrubber inlet every 15 minutes of operation, as applicable. (3) Pressure drop across the wet scrubber system every 15 minutes of operation or amperage to the wet scrubber every 15 minutes of operation, as applicable. (4) Liquor pH as introduced to the wet scrubber...

Wideband EMG telemetry system

NASA Technical Reports Server (NTRS)

Rosatino, S. A.; Westbrook, R. M.

1979-01-01

Miniature, individual crystal-controlled RF transmitters located in EMG pressure sensors simplifies multichannel EMG telemetry for electronic gait monitoring. Transmitters which are assigned operating frequencies within 174 - 216 MHz band have linear frequency response from 20 - 2000 Hz and operate over range of 15 m.

Evaluation of an Integrated Gas-Cooled Reactor Simulator and Brayton Turbine-Generator

NASA Technical Reports Server (NTRS)

Hissam, David Andy; Stewart, Eric T.

2006-01-01

A closed-loop brayton cycle, powered by a fission reactor, offers an attractive option for generating both planetary and in-space electric power. Non-nuclear testing of this type of system provides the opportunity to safely work out integration and system control challenges for a modest investment. Recognizing this potential, a team at Marshall Space Flight Center has evaluated the viability of integrating and testing an existing gas-cooled reactor simulator and a modified commercially available, off-the-shelf, brayton turbine-generator. Since these two systems were developed independently of one another, this evaluation had to determine if they could operate together at acceptable power levels, temperatures, and pressures. Thermal, fluid, and structural analyses show that this combined system can operate at acceptable power levels and temperatures. In addition, pressure drops across the reactor simulator, although higher than desired, are also viewed as acceptable. Three potential working fluids for the system were evaluated: N2, He/Ar, and He/Xe. Other potential issues, such as electrical breakdown in the generator and the operation of the brayton foil bearings using various gas mixtures, were also investigated.

Analysis of pressure spectra measurements in a ducted combustion system. Ph.D. Thesis - Toledo Univ.

NASA Technical Reports Server (NTRS)

Miles, J. H.

1980-01-01

Combustion noise propagation in an operating ducted liquid fuel combustion system is studied in relation to the development of combustion noise prediction and suppression techniques. The presence of combustor emissions in the duct is proposed as the primary mechanism producing the attenuation and dispersion of combustion noise propagating in an operating liquid fuel combustion system. First, a complex mathematical model for calculating attenuation and dispersion taking into account mass transfer, heat transfer, and viscosity effects due to the presence of liquid fuel droplets or solid soot particles is discussed. Next, a simpler single parameter model for calculating pressure auto-spectra and cross-spectra which takes into account dispersion and attenuation due to heat transfer between solid soot particles and air is developed. Then, auto-spectra and cross-spectra obtained from internal pressure measurements in a combustion system consisting of a J-47 combustor can, a spool piece, and a long duct are presented. Last, analytical results obtained with the single parameter model are compared with the experimental measurements. The single parameter model results are shown to be in excellent agreement with the measurements.

Modeling and Analysis of Alternative Concept of ITER Vacuum Vessel Primary Heat Transfer System

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

Carbajo, Juan J; Yoder Jr, Graydon L; Dell'Orco, Giovanni

2010-01-01

A RELAP5-3D model of the ITER (Latin for the way ) vacuum vessel (VV) primary heat transfer system has been developed to evaluate a proposed design change that relocates the heat exchangers (HXs) from the exterior of the tokamak building to the interior. This alternative design protects the HXs from external hazards such as wind, tornado, and aircraft crash. The proposed design integrates the VV HXs into a VV pressure suppression system (VVPSS) tank that contains water to condense vapour in case of a leak into the plasma chamber. The proposal is to also use this water as the ultimatemore » sink when removing decay heat from the VV system. The RELAP5-3D model has been run under normal operating and abnormal (decay heat) conditions. Results indicate that this alternative design is feasible, with no effects on the VVPSS tank under normal operation and with tank temperature and pressure increasing under decay heat conditions resulting in a requirement to remove steam generated if the VVPSS tank low pressure must be maintained.« less

Analysis of pressure spectra measurements in a ducted combustion system

NASA Astrophysics Data System (ADS)

Miles, J. H.

1980-11-01

Combustion noise propagation in an operating ducted liquid fuel combustion system is studied in relation to the development of combustion noise prediction and suppression techniques. The presence of combustor emissions in the duct is proposed as the primary mechanism producing the attenuation and dispersion of combustion noise propagating in an operating liquid fuel combustion system. First, a complex mathematical model for calculating attenuation and dispersion taking into account mass transfer, heat transfer, and viscosity effects due to the presence of liquid fuel droplets or solid soot particles is discussed. Next, a simpler single parameter model for calculating pressure auto-spectra and cross-spectra which takes into account dispersion and attenuation due to heat transfer between solid soot particles and air is developed. Then, auto-spectra and cross-spectra obtained from internal pressure measurements in a combustion system consisting of a J-47 combustor can, a spool piece, and a long duct are presented. Last, analytical results obtained with the single parameter model are compared with the experimental measurements. The single parameter model results are shown to be in excellent agreement with the measurements.

Static Feed Water Electrolysis Subsystem Testing and Component Development

NASA Technical Reports Server (NTRS)

Koszenski, E. P.; Schubert, F. H.; Burke, K. A.

1983-01-01

A program was carried out to develop and test advanced electrochemical cells/modules and critical electromechanical components for a static feed (alkaline electrolyte) water electrolysis oxygen generation subsystem. The accomplishments were refurbishment of a previously developed subsystem and successful demonstration for a total of 2980 hours of normal operation; achievement of sustained one-person level oxygen generation performance with state-of-the-art cell voltages averaging 1.61 V at 191 ASF for an operating temperature of 128F (equivalent to 1.51V when normalized to 180F); endurance testing and demonstration of reliable performance of the three-fluid pressure controller for 8650 hours; design and development of a fluid control assembly for this subsystem and demonstration of its performance; development and demonstration at the single cell and module levels of a unitized core composite cell that provides expanded differential pressure tolerance capability; fabrication and evaluation of a feed water electrolyte elimination five-cell module; and successful demonstration of an electrolysis module pressurization technique that can be used in place of nitrogen gas during the standby mode of operation to maintain system pressure and differential pressures.

Multi-objective control of nonlinear boiler-turbine dynamics with actuator magnitude and rate constraints.

PubMed

Chen, Pang-Chia

2013-01-01

This paper investigates multi-objective controller design approaches for nonlinear boiler-turbine dynamics subject to actuator magnitude and rate constraints. System nonlinearity is handled by a suitable linear parameter varying system representation with drum pressure as the system varying parameter. Variation of the drum pressure is represented by suitable norm-bounded uncertainty and affine dependence on system matrices. Based on linear matrix inequality algorithms, the magnitude and rate constraints on the actuator and the deviations of fluid density and water level are formulated while the tracking abilities on the drum pressure and power output are optimized. Variation ranges of drum pressure and magnitude tracking commands are used as controller design parameters, determined according to the boiler-turbine's operation range. Copyright © 2012 ISA. Published by Elsevier Ltd. All rights reserved.

Solar-Power System Produces High-Pressure Steam

NASA Technical Reports Server (NTRS)

Lansing, F. L.

1985-01-01

Combination of three multistaged solar collectors produces highpressure steam for large-scale continuously operating turbines for generating mechanical or electrical energy. Superheated water vapor drives turbines, attaining an overall system efficiency about 22 percent.

Acoustic leak-detection system for railroad transportation security

NASA Astrophysics Data System (ADS)

Womble, P. C.; Spadaro, J.; Harrison, M. A.; Barzilov, A.; Harper, D.; Hopper, L.; Houchins, E.; Lemoff, B.; Martin, R.; McGrath, C.; Moore, R.; Novikov, I.; Paschal, J.; Rogers, S.

2007-04-01

Pressurized rail tank cars transport large volumes of volatile liquids and gases throughout the country, much of which is hazardous and/or flammable. These gases, once released in the atmosphere, can wreak havoc with the environment and local populations. We developed a system which can non-intrusively and non-invasively detect and locate pinhole-sized leaks in pressurized rail tank cars using acoustic sensors. The sound waves from a leak are produced by turbulence from the gas leaking to the atmosphere. For example, a 500 μm hole in an air tank pressurized to 689 kPa produces a broad audio frequency spectrum with a peak near 40 kHz. This signal is detectable at 10 meters with a sound pressure level of 25 dB. We are able to locate a leak source using triangulation techniques. The prototype of the system consists of a network of acoustic sensors and is located approximately 10 meters from the center of the rail-line. The prototype has two types of acoustic sensors, each with different narrow frequency response band: 40 kHz and 80 kHz. The prototype is connected to the Internet using WiFi (802.11g) transceiver and can be remotely operated from anywhere in the world. The paper discusses the construction, operation and performance of the system.

Quantitative assessment of resilience of a water supply system under rainfall reduction due to climate change

NASA Astrophysics Data System (ADS)

Amarasinghe, Pradeep; Liu, An; Egodawatta, Prasanna; Barnes, Paul; McGree, James; Goonetilleke, Ashantha

2016-09-01

A water supply system can be impacted by rainfall reduction due to climate change, thereby reducing its supply potential. This highlights the need to understand the system resilience, which refers to the ability to maintain service under various pressures (or disruptions). Currently, the concept of resilience has not yet been widely applied in managing water supply systems. This paper proposed three technical resilience indictors to assess the resilience of a water supply system. A case study analysis was undertaken of the Water Grid system of Queensland State, Australia, to showcase how the proposed indicators can be applied to assess resilience. The research outcomes confirmed that the use of resilience indicators is capable of identifying critical conditions in relation to the water supply system operation, such as the maximum allowable rainfall reduction for the system to maintain its operation without failure. Additionally, resilience indicators also provided useful insight regarding the sensitivity of the water supply system to a changing rainfall pattern in the context of climate change, which represents the system's stability when experiencing pressure. The study outcomes will help in the quantitative assessment of resilience and provide improved guidance to system operators to enhance the efficiency and reliability of a water supply system.

14 CFR 31.47 - Burners.

Code of Federal Regulations, 2012 CFR

2012-01-01

... emergency operation. (d) The burner system (including the burner unit, controls, fuel lines, fuel cells...) Five hours at the maximum fuel pressure for which approval is sought, with a burn time for each one... intermediate fuel pressure, with a burn time for each one minute cycle of three to ten seconds. An intermediate...

14 CFR 31.47 - Burners.

Code of Federal Regulations, 2013 CFR

2013-01-01

... emergency operation. (d) The burner system (including the burner unit, controls, fuel lines, fuel cells...) Five hours at the maximum fuel pressure for which approval is sought, with a burn time for each one... intermediate fuel pressure, with a burn time for each one minute cycle of three to ten seconds. An intermediate...

14 CFR 31.47 - Burners.

Code of Federal Regulations, 2010 CFR

2010-01-01

... emergency operation. (d) The burner system (including the burner unit, controls, fuel lines, fuel cells...) Five hours at the maximum fuel pressure for which approval is sought, with a burn time for each one... intermediate fuel pressure, with a burn time for each one minute cycle of three to ten seconds. An intermediate...

14 CFR 31.47 - Burners.

Code of Federal Regulations, 2011 CFR

2011-01-01

... emergency operation. (d) The burner system (including the burner unit, controls, fuel lines, fuel cells...) Five hours at the maximum fuel pressure for which approval is sought, with a burn time for each one... intermediate fuel pressure, with a burn time for each one minute cycle of three to ten seconds. An intermediate...

14 CFR 31.47 - Burners.

Code of Federal Regulations, 2014 CFR

2014-01-01

... emergency operation. (d) The burner system (including the burner unit, controls, fuel lines, fuel cells...) Five hours at the maximum fuel pressure for which approval is sought, with a burn time for each one... intermediate fuel pressure, with a burn time for each one minute cycle of three to ten seconds. An intermediate...

Detection of boundary-layer transitions in wind tunnels

NASA Technical Reports Server (NTRS)

Wood, W. R.; Somers, D. M.

1978-01-01

Accelerometer replaces stethoscope in technique for detection of laminar-to-turbulent boundary-layer transitions on wind-tunnel models. Technique allows measurements above or below atmospheric pressure because human operator is not required within tunnel. Data may be taken from accelerometer, and pressure transducer simultaneously, and delivered to systems for analysis.

49 CFR 393.50 - Reservoirs required.

Code of Federal Regulations, 2014 CFR

2014-10-01

... pressure or vacuum below 70 percent of that indicated by the air or vacuum gauge immediately before the.... Each service reservoir system on a motor vehicle shall be protected against a loss of air pressure or... NECESSARY FOR SAFE OPERATION Brakes § 393.50 Reservoirs required. (a) Reservoir capacity for air-braked...

49 CFR 393.50 - Reservoirs required.

Code of Federal Regulations, 2012 CFR

2012-10-01

... pressure or vacuum below 70 percent of that indicated by the air or vacuum gauge immediately before the.... Each service reservoir system on a motor vehicle shall be protected against a loss of air pressure or... NECESSARY FOR SAFE OPERATION Brakes § 393.50 Reservoirs required. (a) Reservoir capacity for air-braked...

49 CFR 393.50 - Reservoirs required.

Code of Federal Regulations, 2013 CFR

2013-10-01

... pressure or vacuum below 70 percent of that indicated by the air or vacuum gauge immediately before the.... Each service reservoir system on a motor vehicle shall be protected against a loss of air pressure or... NECESSARY FOR SAFE OPERATION Brakes § 393.50 Reservoirs required. (a) Reservoir capacity for air-braked...

The influence of central command on baroreflex resetting during exercise

NASA Technical Reports Server (NTRS)

Raven, Peter B.; Fadel, Paul J.; Smith, Scott A.

2002-01-01

The arterial baroreflex functions as a negative feedback system regulating blood pressure around an established operating point. Paradoxically, a parallel increase in heart rate and blood pressure manifests during exercise. Experimental evidence suggests these events are caused, in part, by a rapid resetting of the baroreflex by central command.

Development of a Linear Stirling System Model with Varying Heat Inputs

NASA Technical Reports Server (NTRS)

Regan, Timothy F.; Lewandowski, Edward J.

2007-01-01

The linear model of the Stirling system developed by NASA Glenn Research Center (GRC) has been extended to include a user-specified heat input. Previously developed linear models were limited to the Stirling convertor and electrical load. They represented the thermodynamic cycle with pressure factors that remained constant. The numerical values of the pressure factors were generated by linearizing GRC's nonlinear System Dynamic Model (SDM) of the convertor at a chosen operating point. The pressure factors were fixed for that operating point, thus, the model lost accuracy if a transition to a different operating point were simulated. Although the previous linear model was used in developing controllers that manipulated current, voltage, and piston position, it could not be used in the development of control algorithms that regulated hot-end temperature. This basic model was extended to include the thermal dynamics associated with a hot-end temperature that varies over time in response to external changes as well as to changes in the Stirling cycle. The linear model described herein includes not only dynamics of the piston, displacer, gas, and electrical circuit, but also the transient effects of the heater head thermal inertia. The linear version algebraically couples two separate linear dynamic models, one model of the Stirling convertor and one model of the thermal system, through the pressure factors. The thermal system model includes heat flow of heat transfer fluid, insulation loss, and temperature drops from the heat source to the Stirling convertor expansion space. The linear model was compared to a nonlinear model, and performance was very similar. The resulting linear model can be implemented in a variety of computing environments, and is suitable for analysis with classical and state space controls analysis techniques.

Hydraulic Control Method for Heating Systems of High-Rise Buildings

NASA Astrophysics Data System (ADS)

Makarov, D.; Chernenkov, V.; Likhachev, I.

2017-11-01

The following article reflects the ideas of possibility to increase energy efficiency of heating systems in high-rise buildings. The article also includes the principle ways of high-rise building heating systems operation as well as traditional engineering decisions aimed at the elimination of the increased pressure effect in heaters. The main disadvantages of such decisions are also presented for the reader. Moreover, the article offers the way of operation for the above-mentioned systems together with the equipment that implements this operation. An economic impact from such energy-saving technology application has been also evaluated.

Automated Pressure Injury Risk Assessment System Incorporated Into an Electronic Health Record System.

PubMed

Jin, Yinji; Jin, Taixian; Lee, Sun-Mi

Pressure injury risk assessment is the first step toward preventing pressure injuries, but traditional assessment tools are time-consuming, resulting in work overload and fatigue for nurses. The objectives of the study were to build an automated pressure injury risk assessment system (Auto-PIRAS) that can assess pressure injury risk using data, without requiring nurses to collect or input additional data, and to evaluate the validity of this assessment tool. A retrospective case-control study and a system development study were conducted in a 1,355-bed university hospital in Seoul, South Korea. A total of 1,305 pressure injury patients and 5,220 nonpressure injury patients participated for the development of a risk scoring algorithm: 687 and 2,748 for the validation of the algorithm and 237 and 994 for validation after clinical implementation, respectively. A total of 4,211 pressure injury-related clinical variables were extracted from the electronic health record (EHR) systems to develop a risk scoring algorithm, which was validated and incorporated into the EHR. That program was further evaluated for predictive and concurrent validity. Auto-PIRAS, incorporated into the EHR system, assigned a risk assessment score of high, moderate, or low and displayed this on the Kardex nursing record screen. Risk scores were updated nightly according to 10 predetermined risk factors. The predictive validity measures of the algorithm validation stage were as follows: sensitivity = .87, specificity = .90, positive predictive value = .68, negative predictive value = .97, Youden index = .77, and the area under the receiver operating characteristic curve = .95. The predictive validity measures of the Braden Scale were as follows: sensitivity = .77, specificity = .93, positive predictive value = .72, negative predictive value = .95, Youden index = .70, and the area under the receiver operating characteristic curve = .85. The kappa of the Auto-PIRAS and Braden Scale risk classification result was .73. The predictive performance of the Auto-PIRAS was similar to Braden Scale assessments conducted by nurses. Auto-PIRAS is expected to be used as a system that assesses pressure injury risk automatically without additional data collection by nurses.

BWR zero pressure containment

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

Dillmann, C.W.; Townsend, H.E.; Nesbitt, L.B.

1992-02-25

This patent describes the operation of a nuclear reactor system, the system including a containment defining a drywall space wherein a nuclear reactor is disposed, there being a suppression pool in the containment with the suppression pool having a wetwell space above a level of the pool to which an non-condensable gases entering the suppression pool can vent. It comprises: continuously exhausting the wetwell space to remove gas mixture therefrom while admitting inflow of air from an atmospheric source thereof to the wetwell during normal operation by blocking off the inflow during a loss-of-coolant-accident whenever a pressure in the wetwellmore » space is above a predetermined value, and subjecting the gas subsequent to its removal from the wetwell to a treatment operation to separate any particulate material entrained therein from the gas mixture.« less

Vaccum drainage system application in the management of operation-related non-regional epidural hematoma

PubMed Central

2013-01-01

Background Epidural intracranial hematoma is one of the most common complications of surgeries for intracranial tumors. The non-regional epidural hematoma is related to severe fluctuation of the intracranial pressure during the operation. The traditional management of hematoma evacuation through craniotomy is time-consuming and may aggravate intracranial pressure imbalance, which causes further complications. We designed a method using vaccum epidural drainage system, and tried to evaluate advantage and the disadvantage of this new technique. Methods Seven patients of intracranial tumors were selected. All of the patients received tumor resection and intra-operative non-regional epidural hematoma was confirmed through intra-operative ultrasound or CT scan. The vaccum drainage system was applied. Another ten patients who received craniotomy for intra-operative non-regional epidural hematoma evacuation were selected as comparison. Regular tests, like serial CT scan, were performed afterward to evaluate the effectiveness and to help deciding when to remove the drainage system. Results The vaccum drainage method was effective in epidual hemotoma clearance and prevented recurrent epidural hemorrhage. The drainage systems were removed within 4 days. All of the patients recovered well. No complications related to the drainage system were observed. Conclusions Compared to the traditional craniotomy, the new method of epidural hemoatoma management using vaccum epidural drainage system proved to be as effective in hematoma clearance, and was less-invasive and easier to perform, with less complication, shorter hospitalization, less economic burden, and better prognosis. PMID:23842198

Behavior of aircraft antiskid braking systems on dry and wet runway surfaces. A slip-velocity-controlled, pressure-bias-modulated system

NASA Technical Reports Server (NTRS)

Stubbs, S. M.; Tanner, J. A.; Smith, E. G.

1979-01-01

The braking and cornering response of a slip velocity controlled, pressure bias modulated aircraft antiskid braking system is investigated. The investigation, conducted on dry and wet runway surfaces, utilized one main gear wheel, brake, and tire assembly of a McDonnell Douglas DC 9 series 10 airplane. The landing gear strut was replaced by a dynamometer. The parameters, which were varied, included the carriage speed, tire loading, yaw angle, tire tread condition, brake system operating pressure, and runway wetness conditions. The effects of each of these parameters on the behavior of the skid control system is presented. Comparisons between data obtained with the skid control system and data obtained from single cycle braking tests without antiskid protection are examined.

Imitative modeling automatic system Control of steam pressure in the main steam collector with the influence on the main Servomotor steam turbine

NASA Astrophysics Data System (ADS)

Andriushin, A. V.; Zverkov, V. P.; Kuzishchin, V. F.; Ryzhkov, O. S.; Sabanin, V. R.

2017-11-01

The research and setting results of steam pressure in the main steam collector “Do itself” automatic control system (ACS) with high-speed feedback on steam pressure in the turbine regulating stage are presented. The ACS setup is performed on the simulation model of the controlled object developed for this purpose with load-dependent static and dynamic characteristics and a non-linear control algorithm with pulse control of the turbine main servomotor. A method for tuning nonlinear ACS with a numerical algorithm for multiparametric optimization and a procedure for separate dynamic adjustment of control devices in a two-loop ACS are proposed and implemented. It is shown that the nonlinear ACS adjusted with the proposed method with the regulators constant parameters ensures reliable and high-quality operation without the occurrence of oscillations in the transient processes the operating range of the turbine loads.

Reactivation and upgrade of the NASA Ames 16-Inch Shock Tunnel - Status report

NASA Technical Reports Server (NTRS)

Bogdanoff, David W.; Zambrana, Horacio A.; Cavolowsky, John A.; Newfield, Mark E.; Cornelison, Charles J.; Miller, Robert J.

1992-01-01

The NASA Ames 16-Inch Shock Tunnel has been reactivated after seventeen years of inactivity. In the years before deactivating the facility, it was operated at enthalpies of 4,700 J/gm and pressures up to 260 atm or at enthalpies of 1900 J/gm over a wide pressure range. Since reactivating, the facility has been operated at enthalpies up to 12,000 J/gm and pressures up to 408 atm. The present paper describes the steps taken in upgrading the facility and summarizes the currently achievable conditions. The selection of the driver gas, the steps taken to improve the driver burn, and the diaphragm opening techniques are described. The pressure and heat flux instrumentation, the optical diagnostics and the data acquisition system are also described.

Pressurized reactor system and a method of operating the same

DOEpatents

Isaksson, J.M.

1996-06-18

A method and apparatus are provided for operating a pressurized reactor system in order to precisely control the temperature within a pressure vessel in order to minimize condensation of corrosive materials from gases on the surfaces of the pressure vessel or contained circulating fluidized bed reactor, and to prevent the temperature of the components from reaching a detrimentally high level, while at the same time allowing quick heating of the pressure vessel interior volume during start-up. Super-atmospheric pressure gas is introduced from the first conduit into the fluidized bed reactor and heat derived reactions such as combustion and gasification are maintained in the reactor. Gas is exhausted from the reactor and pressure vessel through a second conduit. Gas is circulated from one part of the inside volume to another to control the temperature of the inside volume, such as by passing the gas through an exterior conduit which has a heat exchanger, control valve, blower and compressor associated therewith, or by causing natural convection flow of circulating gas within one or more generally vertically extending gas passages entirely within the pressure vessel (and containing heat exchangers, flow rate control valves, or the like therein). Preferably, inert gas is provided as a circulating gas, and the inert gas may also be used in emergency shut-down situations. In emergency shut-down reaction gas being supplied to the reactor is cut off, while inert gas from the interior gas volume of the pressure vessel is introduced into the reactor. 2 figs.

Pressurized reactor system and a method of operating the same

DOEpatents

Isaksson, Juhani M.

1996-01-01

A method and apparatus are provided for operating a pressurized reactor system in order to precisely control the temperature within a pressure vessel in order to minimize condensation of corrosive materials from gases on the surfaces of the pressure vessel or contained circulating fluidized bed reactor, and to prevent the temperature of the components from reaching a detrimentally high level, while at the same time allowing quick heating of the pressure vessel interior volume during start-up. Superatmospheric pressure gas is introduced from the first conduit into the fluidized bed reactor and heat derived reactions such as combustion and gassification are maintained in the reactor. Gas is exhausted from the reactor and pressure vessel through a second conduit. Gas is circulated from one part of the inside volume to another to control the temperature of the inside volume, such as by passing the gas through an exterior conduit which has a heat exchanger, control valve, blower and compressor associated therewith, or by causing natural convection flow of circulating gas within one or more generally vertically extending gas passages entirely within the pressure vessel (and containing heat exchangers, flow rate control valves, or the like therein). Preferably, inert gas is provided as a circulating gas, and the inert gas may also be used in emergency shut-down situations. In emergency shut-down reaction gas being supplied to the reactor is cut off, while inert gas from the interior gas volume of the pressure vessel is introduced into the reactor.

Combustion Instability in an Acid-Heptane Rocket with a Pressurized-Gas Propellant Pumping System

NASA Technical Reports Server (NTRS)

Tischler, Adelbert O.; Bellman, Donald R.

1951-01-01

Results of experimental measurements of low-frequency combustion instability of a 300-pound thrust acid-heptane rocket engine were compared to the trends predicted by an analysis of combustion instability in a rocket engine with a pressurized-gas propellant pumping system. The simplified analysis, which assumes a monopropellant model, was based on the concept of a combustion the delay occurring from the moment of propellant injection to the moment of propellant combustion. This combustion time delay was experimentally measured; the experimental values were of approximately half the magnitude predicted by the analysis. The pressure-fluctuation frequency for a rocket engine with a characteristic length of 100 inches and operated at a combustion-chamber pressure of 280 pounds per square inch absolute was 38 cycles per second; the analysis indicated. a frequency of 37 cycles per second. Increasing combustion-chamber characteristic length decreased the pressure-fluctuation frequency, in conformity to the analysis. Increasing the chamber operating pressure or increasing the injector pressure drop increased the frequency. These latter two effects are contrary to the analysis; the discrepancies are attributed to the conflict between the assumptions made to simplify the analysis and the experimental conditions. Oxidant-fuel ratio had no apparent effect on the experimentally measured pressure-fluctuation frequency for acid-heptane ratios from 3.0 to 7.0. The frequencies decreased with increased amplitude of the combustion-chamber pressure variations. The analysis indicated that if the combustion time delay were sufficiently short, low-frequency combustion instability would be eliminated.

Low-Cost Cold-Gas RCS for the Sloshsat Small Satellite

NASA Astrophysics Data System (ADS)

Adler, S.; Warshavsky, A.; Peretz, A.

2002-01-01

Cold gas thrusters usually provide an inexpensive, highly reliable, low-power consuming, non contaminating, and safe auxiliary propulsion means for small spacecraft. A low-cost cold-gas Reaction Control System (RCS) has been designed and developed to provide linear acceleration and rotation control of the SLOSHSAT satellite for liquid-slosh experimentation. This ESA-sponsored mini-spacecraft will be launched by the Space Shuttle and ejected into space from its hitchhiker bay. The RCS was designed and developed according to man rated safety standards, as required by NASA. The RCS comprises four identical spherical carbon/epoxy-wound stainless steel tanks, which store 1.6 kg of nitrogen at 600 bars, corresponding to a maximum rated temperature of 70°C. The relatively high pressure enables economic utilization of the limited space available in small satellites. The tanks are of a "leak before burst" design, which was subjected to a comprehensive finite-element stress analysis. They were developed and tested in accordance with MIL-STD-1522A, with a proof pressure and a minimum burst pressure of 1000 and 1700 bars, respectively. Each tank has an internal volume of 0.97 l, and is equipped with an attached accessories assembly, that includes a pyrovalve and a filter. The RCS was supplied with the tanks prepressurized and sealed to 473 bars (at 20°C). The whole system is pressurized only after the satellite is in its orbit, by activating the tank's pyrovalve. This unique approach enables to supply a sealed RCS system and propellant loading activities are not necessary before launch. Additionally, this approach has safety advantages that were meaningful to meet the NASA safety requirements. The pyrovalve includes a RAFAEL-developed initiator, which complies with MIL-STD-1576, and passed all required testing, including ESD tests with the resistor removed, as demanded by NASA for approval. The pyrovalve is of a "self seal" design, which includes a sealing mechanism, that seals the system from contamination during the pyrovalve actuation. The test port valve allows proof-pressure and leakage testing of the assembled system. The tanks and their accessories were subjected to extensive qualification testing and met the requirements of a stringent acceptance test procedure. The N2 propellant is supplied to twelve 0.8-N thrusters, at a steady regulated pressure of 15.5 bars. Accurate regulated pressure is obtained by a two stage regulating system, which accepts pressure input range of 600 to 40 bar. The thrusters were especially developed to meet the specific program requirements. They will normally be operated in pairs. For safety reasons and redundancy two relief valves are mounted downstream of the regulators. Each valve can handle the total flow with a minimum pressure rise, which defines the Maximum Operating Pressure (MEOP) in the low-pressure section of the system. The pressure surge phenomenon that follows the pyrovalve actuation was precisely analyzed, and tested in simulated conditions. A surge damper is successfully applied to the gas pipeline, significantly lowering the pressure surge. The sensitivity of the regulated pressure to the pulse modulation of the thrusters was examined. Due to the lock pressure of the regulators, and the difference between the static and dynamic regulated pressure levels, the average pressure was found to depend on the pulse duty cycle. This phenomenon was investigated and a model that predicts the pressure level according to the mass flow rate and pulse modulation was established. A breadboard test system, that completely simulates the pneumatic nature of the SLOSHSAT RCS, was constructed and used for ground test evaluation of the RCS performance in various modes of operation (continuous and pulses of various duty cycles). Computerized data acquisition and data reduction was used for pressure, temperature and mass flow measurements at several locations in the system. The breadboard system was also used for development experiments and investigation of various transient and steady state phenomena to enable successful performance prediction for operation in space. In order to establish appropriate assembly procedures for the RCS in the limited space allocated for it in the SLOSHSAT, a mock-up of the final satellite configuration, an Assembly and Testing System (ATS), was constructed. The complete RCS integrated in the ATS was subjected to vibration tests, followed by proof pressure, leakage and performance tests, as a part of the RCS qualification. All RCS components, except for the thrusters, are off-the-shelf items, adapted for space application by meeting stringent NASA/ESA man-rated mission requirements. A cooperative effort between FOKKER-SPACE and NLR of the Netherlands and RAFAEL of Israel enabled a very efficient RCS architecture that satisfies the limiting volume constraints. This approach made it possible to attain a man-rated, space-qualified cold-gas propulsion system with low-cost and safety and high- reliability attributes.

Space Shuttle life support systems - A status report

NASA Technical Reports Server (NTRS)

Faget, M. A.; Guy, W. W.

1981-01-01

The Space Shuttle Program has two independent life support systems. One provides the basic environmental control for the Orbiter cabin while the second enables the crewmen to function outside the spacecraft for extravehicular operation. Although both of these systems were developed and fabricated under contract to NASA, all system-level testing was conducted at the Johnson Space Center. The paper will discuss the results of this testing which, in part, includes: (1) certification of the Orbiter cabin atmospheric pressure and composition control system at three operational pressures (8 psia, 9 psia and 14.7 psia); (2) certification of the Orbiter atmospheric revitalization system at 9 psia and 14.7 psia; (3) manrating of the Orbiter airlock at 14.7 psia, 9 psia and vacuum; and (4) certification of the space suit/life support system in the airlock and at deep space thermal/vacuum conditions. In addition, pertinent flight information from the on-orbit performance of the Shuttle life support systems will be presented.

Multi-Element Unstructured Analyses of Complex Valve Systems

NASA Technical Reports Server (NTRS)

Sulyma, Peter (Technical Monitor); Ahuja, Vineet; Hosangadi, Ashvin; Shipman, Jeremy

2004-01-01

The safe and reliable operation of high pressure test stands for rocket engine and component testing places an increased emphasis on the performance of control valves and flow metering devices. In this paper, we will present a series of high fidelity computational analyses of systems ranging from cryogenic control valves and pressure regulator systems to cavitating venturis that are used to support rocket engine and component testing at NASA Stennis Space Center. A generalized multi-element framework with sub-models for grid adaption, grid movement and multi-phase flow dynamics has been used to carry out the simulations. Such a framework provides the flexibility of resolving the structural and functional complexities that are typically associated with valve-based high pressure feed systems and have been difficult to deal with traditional CFD methods. Our simulations revealed a rich variety of flow phenomena such as secondary flow patterns, hydrodynamic instabilities, fluctuating vapor pockets etc. In the paper, we will discuss performance losses related to cryogenic control valves, and provide insight into the physics of the dominant multi-phase fluid transport phenomena that are responsible for the choking like behavior in cryogenic control elements. Additionally, we will provide detailed analyses of the modal instability that is observed in the operation of the dome pressure regulator valve. Such instabilities are usually not localized and manifest themselves as a system wide phenomena leading to an undesirable chatter at high flow conditions.

A Study to Determine the Evolution of Advances in Medical Technology Expected in the Next 25 Years and Possible Impacts on Coast Guard Operations and Support Programs.

DTIC Science & Technology

1980-05-01

abnormalities in pressure tracings of the systemic, the central venous or pulmonary arterial circulation. At some sites (especially the Latter-Day Saints...accurate measurement of central venous pressure has been by direct venous cannulation. However, a group of Swiss doctors has extended the principle of... venous stop flow pressure to develop a noninvasive method of measuring central venous pressure. The method consists of venous auscultation at the thoracic

A data base and analysis program for shuttle main engine dynamic pressure measurements. Appendix F: Data base plots for SSME tests 750-120 through 750-200

NASA Technical Reports Server (NTRS)

Coffin, T.

1986-01-01

A dynamic pressure data base and data base management system developed to characterize the Space Shuttle Main Engine (SSME) dynamic pressure environment is presented. The data base represents dynamic pressure measurements obtained during single engine hot firing tests of the SSME. Software is provided to permit statistical evaluation of selected measurements under specified operating conditions. An interpolation scheme is also included to estimate spectral trends with SSME power level.

120 Hz pulse tube cryocooler for fast cooldown to 50 K

NASA Astrophysics Data System (ADS)

Vanapalli, Srinivas; Lewis, Michael; Gan, Zhihua; Radebaugh, Ray

2007-02-01

A pulse tube cryocooler operating at 120Hz with 3.5MPa average pressure achieved a no-load temperature of about 49.9K and a cooldown time to 80K of 5.5min. The net refrigeration power at 80K was 3.35W with an efficiency of 19.7% of Carnot when referred to input pressure-volume (PV or acoustic) power. Such low temperatures have not been previously achieved for operating frequencies above 100Hz. The high frequency operation leads to reduced cryocooler volume for a given refrigeration power, which is important to many applications and can enable development of microcryocoolers for microelectromechanical system applications.

Sensor and methods of detecting target materials and situations in closed systems

DOEpatents

Mee, David K.; Ripley, Edward B.; Nienstedt, Zachary C.; Nienstedt, Alex W.; Howell, Jr., Layton N.

2018-03-13

Disclosed is a passive, in-situ pressure sensor. The sensor includes a sensing element having a ferromagnetic metal and a tension inducing mechanism coupled to the ferromagnetic metal. The tension inducing mechanism is operable to change a tensile stress upon the ferromagnetic metal based on a change in pressure in the sensing element. Changes in pressure are detected based on changes in the magnetic switching characteristics of the ferromagnetic metal when subjected to an alternating magnetic field caused by the change in the tensile stress. The sensing element is embeddable in a closed system for detecting pressure changes without the need for any penetrations of the system for power or data acquisition by detecting changes in the magnetic switching characteristics of the ferromagnetic metal caused by the tensile stress.

Flight evaluation of a pneumatic system for unsteady pressure measurements using conventional sensors

NASA Technical Reports Server (NTRS)

Curry, Robert E.; Gilyard, Glenn B.

1989-01-01

A flight experiment was conducted to evaluate a pressure measurement system which uses pneumatic tubing and remotely located electronically scanned pressure transducer modules for in-flight unsteady aerodynamic studies. A parametric study of tubing length and diameter on the attenuation and lag of the measured signals was conducted. The hardware was found to operate satisfactorily at rates of up to 500 samples/sec per port in flight. The signal attenuation and lag due to tubing were shown to increase with tubing length, decrease with tubing diameter, and increase with altitude over the ranges tested. Measurable signal levels were obtained for even the longest tubing length tested, 4 ft, at frequencies up to 100 Hz. This instrumentation system approach provides a practical means of conducting detailed unsteady pressure surveys in flight.

Excess air during aquifer storage and recovery in an arid basin (Las Vegas Valley, USA)

NASA Astrophysics Data System (ADS)

Solomon, D. Kip; Cole, Erin; Leising, Joseph F.

2011-02-01

The Las Vegas Valley Water District in Nevada, USA, has operated an artificial recharge (AR) program since 1989. In summer 2001, observations of gas exsolving from tap water prompted a study that revealed total dissolved gas (TDG) pressures approaching 2 atm with a gas composition that it is predominantly air. Measurements of TDG pressure at well heads and in the distribution system indicated two potential mechanisms for elevated TDG pressures: (1) air entrainment during AR operations, and (2) temperature changes between the winter recharge season and the summer withdrawal season. Air entrainment during pumping was investigated by intentionally allowing the forebay (upstream reservoir) of a large pumping station to drawdown to the point of vortex formation. This resulted in up to a 0.7 atm increase in TDG pressure. In general, the solubility of gases in water decreases as the temperature increases. In the Las Vegas Valley, water that acquired a modest amount of dissolved gas during winter artificial recharge operations experienced an increase in dissolved gas pressure (0.04 atm/°C) as the water warmed in the subsurface. A combination of air entrainment during AR operations and its amplification by temperature increase after recharge can account for most of the observed amounts of excess gas at this site.

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...

Battery-Free Smart Sock for Abnormal Relative Plantar Pressure Monitoring.

PubMed

Lin, Xiaoyou; Seet, Boon-Chong

2017-04-01

This paper presents a new design of a wearable plantar pressure monitoring system in the form of a smart sock for sensing abnormal relative pressure changes. One advantage of this approach is that with a battery-free design, this system can be powered solely by radio frequency (RF) energy harvested from a radio frequency identification (RFID) reader unit hosted on a smartphone of the wearer. At the same time, this RFID reader can read foot pressure values from an embedded sensor-tag in the sock. A pressure sensing matrix made of conductive fabric and flexible piezo-resistive material is integrated into the sock during the knitting process. Sensed foot pressures are digitized and stored in the memory of a sensor-tag, thus allowing relative foot pressure values to be tracked. The control unit of the smart sock is assembled on a flexible printed circuit board (FPC) that can be strapped to the lower limb and detached easily when it is not in use. Experiments show that the system can operate reliably in both tasks of RF energy harvesting and pressure measurement.

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

NASA Technical Reports Server (NTRS)

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

2005-01-01

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

An implantable blood pressure and flow transmitter.

NASA Technical Reports Server (NTRS)

Rader, R. D.; Meehan, J. P.; Henriksen, J. K. C.

1973-01-01

A miniature totally implantable FM/FM telemetry system has been developed to simultaneously measure blood pressure and blood flow, thus providing an appreciation of the hemodynamics of the circulation to the entire body or to a particular organ. Developed for work with animal subjects, the telemetry system's transmission time is controlled by an RF signal that permits an operating life of several months. Pressure is detected by a miniature intravascular transducer and flow is detected by an extravascular interferometric ultrasonic technique. Both pressure and flow are calibrated prior to implanting. The pressure calibration can be checked after the implanting by cannulation; flow calibration can be verified only at the end of the experiment by determining the voltage output from the implanted sensing system as a function of several measured flow rates. The utility of this device has been established by its use in investigating canine renal circulation during exercise, emotional encounters, administration of drugs, and application of accelerative forces.

Innovative Method for Developing a Helium Pressurant Tank Suitable for the Upper Stage Flight Experiment

NASA Technical Reports Server (NTRS)

DeLay, Tom K.; Munafo, Paul (Technical Monitor)

2001-01-01

The AFRL USFE project is an experimental test bed for new propulsion technologies. It will utilize ambient temperature fuel and oxidizers (Kerosene and Hydrogen peroxide). The system is pressure fed, not pump fed, and will utilize a helium pressurant tank to drive the system. Mr. DeLay has developed a method for cost effectively producing a unique, large pressurant tank that is not commercially available. The pressure vessel is a layered composite structure with an electroformed metallic permeation barrier. The design/process is scalable and easily adaptable to different configurations with minimal cost in tooling development 1/3 scale tanks have already been fabricated and are scheduled for testing. The full-scale pressure vessel (50" diameter) design will be refined based on the performance of the sub-scale tank. The pressure vessels have been designed to operate at 6,000 psi. a PV/W of 1.92 million is anticipated.

Relationship of new-onset systemic hypertension and normal pressure hydrocephalus.

PubMed

Mysiw, W J; Jackson, R D

1990-01-01

Communicating normal pressure hydrocephalus (NPH) is an important remote complication of traumatic brain injury (TBI). The diagnosis of this hydrocephalus depends largely on clinical signs and symptoms, including cognitive deterioration, gait changes and incontinence. However, many of these signs are also seen during post-traumatic amnesia, making early recognition of this syndrome difficult. A case study of one man post-TBI, who presented with new-onset hypertension as a sign of NPH, prompted a retrospective chart review of all patients admitted over a 2-year period with a diagnosis of NPH. Ninety per cent of patients had one or more of the classic triad of NPH and 25% of patients had symptoms suggestive of raised intracranial pressure (unexplained nausea, headache and visual disturbance). Mean systolic and diastolic blood pressures among the 20 subjects for six consecutive days pre-operatively compared with those for days 8-14 and 15-21 post-operatively showed no significant differences; a subgroup of five patients (25%), however, demonstrated a significant change in blood pressure temporally related to shunting. We suggest that demonstration of new-onset systemic hypertension may also be a clinical sign suggestive of NPH useful in the evaluation of the TBI patient.

Micromachined Joule-Thomson coolers for cooling low-temperature detectors and electronics

NASA Astrophysics Data System (ADS)

ter Brake, Marcel; Lerou, P. P. P. M.; Burger, J. F.; Holland, H. J.; Derking, J. H.; Rogalla, H.

2017-11-01

The performance of electronic devices can often be improved by lowering the operating temperature resulting in lower noise and larger speed. Also, new phenomena can be applied at low temperatures, as for instance superconductivity. In order to fully exploit lowtemperature electronic devices, the cryogenic system (cooler plus interface) should be `invisible' to the user. It should be small, low-cost, low-interference, and above all very reliable (long-life). The realization of cryogenic systems fulfilling these requirements is the topic of research of the Cooling and Instrumentation group at the University of Twente. A MEMS-based cold stage was designed and prototypes were realized and tested. The cooler operates on basis of the Joule-Thomson effect. Here, a high-pressure gas expands adiabatically over a flow restriction and thus cools and liquefies. Heat from the environment (e.g., an optical detector) can be absorbed in the evaporation of the liquid. The evaporated working fluid returns to the low-pressure side of the system via a counter-flow heat exchanger. In passing this heat exchanger, it takes up heat from the incoming high-pressure gas that thus is precooled on its way to the restriction. The cold stage consists of a stack of three glass wafers. In the top wafer, a high-pressure channel is etched that ends in a flow restriction with a height of typically 300 nm. An evaporator volume crosses the center wafer into the bottom wafer. This bottom wafer contains the lowpressure channel thus forming a counter-flow heat exchanger. A design aiming at a net cooling power of 10 mW at 96 K and operating with nitrogen as the working fluid was optimized based on the minimization of entropy production. The optimum cold finger measures 28 mm x 2.2 mm x 0.8 mm operating with a nitrogen flow of 1 mg/s at a high pressure of 80 bar and a low pressure of 6 bar. The design and fabrication of the coolers will be discussed along with experimental results.

40 CFR Table 3 to Subpart Ddddd of... - Operating Limits for Boilers and Process Heaters With Mercury Emission Limits and Boilers and...

Code of Federal Regulations, 2010 CFR

2010-07-01

... minimum pressure drop and liquid flow-rate at or above the operating levels established during the... leak detection system alarm does not sound more than 5 percent of the operating time during a 6-month... control Maintain the minimum sorbent or carbon injection rate at or above the operating levels established...

40 CFR Table 3 to Subpart Ddddd of... - Operating Limits for Boilers and Process Heaters With Mercury Emission Limits and Boilers and...

Code of Federal Regulations, 2011 CFR

2011-07-01

... minimum pressure drop and liquid flow-rate at or above the operating levels established during the... leak detection system alarm does not sound more than 5 percent of the operating time during a 6-month... control Maintain the minimum sorbent or carbon injection rate at or above the operating levels established...

Investigation of noise sources and propagation in external gear pumps

NASA Astrophysics Data System (ADS)

Opperwall, Timothy J.

Oil hydraulics is widely accepted as the best technology for transmitting power in many engineering applications due to its advantages in power density, control, layout flexibility, and efficiency. Due to these advantages, hydraulic systems are present in many different applications including construction, agriculture, aerospace, automotive, forestry, medical, and manufacturing, just to identify a few. Many of these applications involve the systems in close proximity to human operators and passengers where noise is one of the main constraints to the acceptance and spread of this technology. As a key component in power transfer, displacement machines can be major sources of noise in hydraulic systems. Thus, investigation into the sources of noise and discovering strategies to reduce noise is a key part of applying fluid power systems to a wider range of applications, as well as improving the performance of current hydraulic systems. The present research aims to leverage previous efforts and develop new models and experimental techniques in the topic of noise generation caused by hydrostatic units. This requires challenging and surpassing current accepted methods in the understanding of noise in fluid power systems. This research seeks to expand on the previous experimental and modeling efforts by directly considering the effect that system and component design changes apply on the total sound power and the sound frequency components emitted from displacement machines and the attached lines. The case of external gear pumps is taken as reference for a new model to understand the generation and transmission of noise from the sources out to the environment. The lumped parameter model HYGESim (HYdraulic GEar machine Simulator) was expanded to investigate the dynamic forces on the solid bodies caused by the pump operation and to predict interactions with the attached system. Vibration and sound radiation were then predicted using a combined finite element and boundary element vibro-acoustic model as well as the influence of additional models for system components to better understand the essential problems of noise generation in hydraulic systems. This model is a step forward for the field due to the coupling of an advanced internal model of pump operation coupled to a detailed vibro-acoustic model. Several experimental studies were also completed in order to advance the current science. The first study validated the pump model in terms of outlet pressure ripple prediction through comparison to experimentally measured results for the reference pump as well as prototype pumps designed for low outlet pressure ripple. The second study focused on the air-borne noise through sound pressure and intensity measurements on reference and prototype pumps at steady-state operating conditions. A third study over a wide range of operating speeds and pressures was completed to explore the impact of operating condition and system design to greater detail through measuring noise and vibration in the working fluid, the system structures, and the air. Applying the knowledge gained through experimental and simulation studies has brought new advances in the understanding of the physics of noise generation and propagation in hydraulic components and systems. The focus of the combined simulation and modeling approach is to clearly understand the different contributions from noise sources and surpasses the previous methods that focus on the outlet pressure ripple alone as a source of noise. The application of the new modeling and experimental approach allows for new advances which directly contribute to advancing the science of noise in hydraulic applications and the design of new quieter hydrostatic units and hydraulic systems.

Modernization and Activation of the NASA Ames 11- by 11-Foot Transonic Wind Tunnel

NASA Technical Reports Server (NTRS)

Kmak, Frank J.

2000-01-01

The Unitary Plan Wind Tunnel (UPWT) was modernized to improve performance, capability, productivity, and reliability. Automation systems were installed in all three UPWT tunnel legs and the Auxiliaries facility. Major improvements were made to the four control rooms, model support systems, main drive motors, and main drive speed control. Pressure vessel repairs and refurbishment to the electrical distribution system were also completed. Significant changes were made to improve test section flow quality in the 11-by 11-Foot Transonic leg. After the completion of the construction phase of the project, acceptance and checkout testing was performed to demonstrate the capabilities of the modernized facility. A pneumatic test of the tunnel circuit was performed to verify the structural integrity of the pressure vessel before wind-on operations. Test section turbulence, flow angularity, and acoustic parameters were measured throughout the tunnel envelope to determine the effects of the tunnel flow quality improvements. The new control system processes were thoroughly checked during wind-off and wind-on operations. Manual subsystem modes and automated supervisory modes of tunnel operation were validated. The aerodynamic and structural performance of both the new composite compressor rotor blades and the old aluminum rotor blades was measured. The entire subsonic and supersonic envelope of the 11-by 11-Foot Transonic leg was defined up to the maximum total pressure.

Investigation of a para-ortho hydrogen reactor for application to spacecraft sensor cooling

NASA Technical Reports Server (NTRS)

Nast, T. C.

1983-01-01

The utilization of solid hydrogen in space for sensor and instrument cooling is a very efficient technique for long term cooling or for cooling at high heat rates. The solid hydrogen can provide temperatures as low as 7 to 8 K to instruments. Vapor cooling is utilized to reduce parasitic heat inputs to the 7 to 8 K stage and is effective in providing intermediate cooling for instrument components operating at higher temperatures. The use of solid hydrogen in place of helium may lead to weight reductions as large as a factor of ten and an attendent reduction in system volume. The results of an investigation of a catalytic reactor for use with a solid hydrogen cooling system is presented. Trade studies were performed on several configurations of reactor to meet the requirements of high reactor efficiency with low pressure drop. Results for the selected reactor design are presented for both liquid hydrogen systems operating at near atmospheric pressure and the solid hydrogen cooler operating as low as 1 torr.

Evaluation of Agency Non-Code Layered Pressure Vessels (LPVs)

NASA Technical Reports Server (NTRS)

Prosser, William H.

2014-01-01

In coordination with the Office of Safety and Mission Assurance and the respective Center Pressure System Managers (PSMs), the NASA Engineering and Safety Center (NESC) was requested to formulate a consensus draft proposal for the development of additional testing and analysis methods to establish the technical validity, and any limitation thereof, for the continued safe operation of facility non-code layered pressure vessels. The PSMs from each NASA Center were asked to participate as part of the assessment team by providing, collecting, and reviewing data regarding current operations of these vessels. This report contains the outcome of the assessment and the findings, observations, and NESC recommendations to the Agency and individual NASA Centers.

Evaluation of Agency Non-Code Layered Pressure Vessels (LPVs). Corrected Copy, Aug. 25, 2014

NASA Technical Reports Server (NTRS)

Prosser, William H.

2014-01-01

In coordination with the Office of Safety and Mission Assurance and the respective Center Pressure System Managers (PSMs), the NASA Engineering and Safety Center (NESC) was requested to formulate a consensus draft proposal for the development of additional testing and analysis methods to establish the technical validity, and any limitation thereof, for the continued safe operation of facility non-code layered pressure vessels. The PSMs from each NASA Center were asked to participate as part of the assessment team by providing, collecting, and reviewing data regarding current operations of these vessels. This report contains the outcome of the assessment and the findings, observations, and NESC recommendations to the Agency and individual NASA Centers.

An Optical Fibre Depth (Pressure) Sensor for Remote Operated Vehicles in Underwater Applications

PubMed Central

Duraibabu, Dinesh Babu; Poeggel, Sven; Omerdic, Edin; Capocci, Romano; Lewis, Elfed; Newe, Thomas; Leen, Gabriel; Toal, Daniel; Dooly, Gerard

2017-01-01

A miniature sensor for accurate measurement of pressure (depth) with temperature compensation in the ocean environment is described. The sensor is based on an optical fibre Extrinsic Fabry-Perot interferometer (EFPI) combined with a Fibre Bragg Grating (FBG). The EFPI provides pressure measurements while the Fibre Bragg Grating (FBG) provides temperature measurements. The sensor is mechanically robust, corrosion-resistant and suitable for use in underwater applications. The combined pressure and temperature sensor system was mounted on-board a mini remotely operated underwater vehicle (ROV) in order to monitor the pressure changes at various depths. The reflected optical spectrum from the sensor was monitored online and a pressure or temperature change caused a corresponding observable shift in the received optical spectrum. The sensor exhibited excellent stability when measured over a 2 h period underwater and its performance is compared with a commercially available reference sensor also mounted on the ROV. The measurements illustrates that the EFPI/FBG sensor is more accurate for depth measurements (depth of ~0.020 m). PMID:28218727

HVAC SYSTEMS IN THE CURRENT STOCK OF US K-12 SCHOOLS

EPA Science Inventory

The report summarizes information on heating, ventilating, an air- conditioning (HVAC) systems commonly found in U. S. school buildings and the effect that operating these systems has on indoor radon levels. The report describes the ability of various HVAC systems to pressurize a...

HVAC SYSTEMS IN THE CURRENT STOCK OF U.S. K-12 SCHOOLS

EPA Science Inventory

The report summarizes information on heating, ventilating, an air- conditioning (HVAC) systems commonly found in U. S. school buildings and the effect that operating these systems has on indoor radon levels. The report describes the ability of various HVAC systems to pressurize a...

A Low-Pressure Oxygen Storage System for Oxygen Supply in Low-Resource Settings.

PubMed

Rassool, Roger P; Sobott, Bryn A; Peake, David J; Mutetire, Bagayana S; Moschovis, Peter P; Black, Jim Fp

2017-12-01

Widespread access to medical oxygen would reduce global pneumonia mortality. Oxygen concentrators are one proposed solution, but they have limitations, in particular vulnerability to electricity fluctuations and failure during blackouts. The low-pressure oxygen storage system addresses these limitations in low-resource settings. This study reports testing of the system in Melbourne, Australia, and nonclinical field testing in Mbarara, Uganda. The system included a power-conditioning unit, a standard oxygen concentrator, and an oxygen store. In Melbourne, pressure and flows were monitored during cycles of filling/emptying, with forced voltage fluctuations. The bladders were tested by increasing pressure until they ruptured. In Mbarara, the system was tested by accelerated cycles of filling/emptying and then run on grid power for 30 d. The low-pressure oxygen storage system performed well, including sustaining a pressure approximately twice the standard working pressure before rupture of the outer bag. Flow of 1.2 L/min was continuously maintained to a simulated patient during 30 d on grid power, despite power failures totaling 2.9% of the total time, with durations of 1-176 min (mean 36.2, median 18.5). The low-pressure oxygen storage system was robust and durable, with accelerated testing equivalent to at least 2 y of operation revealing no visible signs of imminent failure. Despite power cuts, the system continuously provided oxygen, equivalent to the treatment of one child, for 30 d under typical power conditions for sub-Saharan Africa. The low-pressure oxygen storage system is ready for clinical field trials. Copyright © 2017 by Daedalus Enterprises.

Zero Gravity Cryogenic Vent System Concepts for Upper Stages

NASA Astrophysics Data System (ADS)

Ravex, Alain; Flachbart, Robin; Holt, Barney

The capability to vent in zero gravity without resettling is a technology need that involves practically all uses of sub-critical cryogenics in space. Venting without resettling would extend cryogenic orbital transfer vehicle capabilities. However, the lack of definition regarding liquid/ullage orientation coupled with the somewhat random nature of the thermal stratification and resulting pressure rise rates, lead to significant technical challenges. Typically a zero gravity vent concept, termed a thermodynamic vent system (TVS), consists of a tank mixer to destratify the propellant, combined with a Joule-Thomson (J-T) valve to extract thermal energy from the propellant. Marshall Space Flight Center's (MSFC's) Multipurpose Hydrogen Test Bed (MHTB) was used to test both spray bar and axial jet TVS concepts. The axial jet system consists of a recirculation pump heat exchanger unit. The spray bar system consists of a recirculation pump, a parallel flow concentric tube, heat exchanger, and a spray bar positioned close to the longitudinal axis of the tank. The operation of both concepts is similar. In the mixing mode, the recirculation pump withdraws liquid from the tank and sprays it into the tank liquid, ullage, and exposed tank surfaces. When energy extraction is required, a small portion of the recirculated liquid is passed sequentially through the J-T expansion valve, the heat exchanger, and is vented overboard. The vented vapor cools the circulated bulk fluid, thereby removing thermal energy and reducing tank pressure. The pump operates alone, cycling on and off, to destratify the tank liquid and ullage until the liquid vapor pressure reaches the lower set point. At that point, the J-T valve begins to cycle on and off with the pump. Thus, for short duration missions, only the mixer may operate, thus minimizing or even eliminating boil-off losses. TVS performance testing demonstrated that the spray bar was effective in providing tank pressure control within a 6.89 kPa (1psi) band for fill levels of 90%, 50%, and 25%. Complete destratification of the liquid and ullage was achieved at these fill levels. The axial jet was effective in providing tank pressure control within the same pressure control band at the 90% fill level. However, at the 50% level, the system reached a point at which it was unable to extract enough energy to keep up with the heat leak into the tank. Due to a hardware problem, the recirculation pump operated well below the axial jet design flow rate. Therefore, it is likely that the performance of the axial jet would have improved had the pump operated at the proper flow rate. A CFD model is being used to determine if the desired axial jet performance would be achieved if a higher pump flow rate were available. Testing conducted thus far has demonstrated that both TVS concepts can be effective in destratifying a propellant tank, rejecting stored heat energy, and thus, controlling tank pressure.

A review of acoustic dampers applied to combustion chambers in aerospace industry

NASA Astrophysics Data System (ADS)

Zhao, Dan; Li, X. Y.

2015-04-01

In engine combustion systems such as rockets, aero-engines and gas turbines, pressure fluctuations are always present, even during normal operation. One of design prerequisites for the engine combustors is stable operation, since large-amplitude self-sustained pressure fluctuations (also known as combustion instability) have the potential to cause serious structural damage and catastrophic engine failure. To dampen pressure fluctuations and to reduce noise, acoustic dampers are widely applied as a passive control means to stabilize combustion/engine systems. However, they cannot respond to the dynamic changes of operating conditions and tend to be effective over certain narrow range of frequencies. To maintain their optimum damping performance over a broad frequency range, extensive researches have been conducted during the past four decades. The present work is to summarize the status, challenges and progress of implementing such acoustic dampers on engine systems. The damping effect and mechanism of various acoustic dampers, such as Helmholtz resonators, perforated liners, baffles, half- and quarter-wave tube are introduced first. A summary of numerical, experimental and theoretical studies are then presented to review the progress made so far. Finally, as an alternative means, ';tunable acoustic dampers' are discussed. Potential, challenges and issues associated with the dampers practical implementation are highlighted.

Control apparatus for hot gas engine

DOEpatents

Stotts, Robert E.

1986-01-01

A mean pressure power control system for a hot gas (Stirling) engine utilizing a plurality of supply tanks for storing a working gas at different pressures. During pump down operations gas is bled from the engine by a compressor having a plurality of independent pumping volumes. In one embodiment of the invention, a bypass control valve system allows one or more of the compressor volumes to be connected to the storage tanks. By selectively sequencing the bypass valves, a capacity range can be developed over the compressor that allows for lower engine idle pressures and more rapid pump down rates.

Remote sensing of atmospheric pressure and sea state using laser altimeters

NASA Technical Reports Server (NTRS)

Gardner, C. S.

1985-01-01

Short-pulse multicolor laser ranging systems are currently being developed for satellite ranging applications. These systems use Q-switched pulsed lasers and streak-tube cameras to provide timing accuracies approaching a few picoseconds. Satellite laser ranging systems have been used to evaluate many important geophysical phenomena such as fault motion, polar motion and solid earth tides, by measuring the orbital perturbations of retroreflector equipped satellites. Some existing operational systems provide range resolution approaching a few millimeters. There is currently considerable interest in adapting these highly accurate systems for use as airborne and satellite based altimeters. Potential applications include the measurement of sea state, ground topography and atmospheric pressure. This paper reviews recent progress in the development of multicolor laser altimeters for use in monitoring sea state and atmospheric pressure.

46 CFR 176.810 - Fire protection.

Code of Federal Regulations, 2013 CFR

2013-10-01

... systems, including sensors and alarms. (b) The owner, managing operator, or a qualified servicing facility... satisfaction of the Coast Guard inspector. Dry chemical (cartridge operated) Examine pressure cartridge and... and nozzle to see if they are clear. Insert charged cartridge. Ensure dry chemical is free flowing...

46 CFR 176.810 - Fire protection.

Code of Federal Regulations, 2012 CFR

2012-10-01

... systems, including sensors and alarms. (b) The owner, managing operator, or a qualified servicing facility... satisfaction of the Coast Guard inspector. Dry chemical (cartridge operated) Examine pressure cartridge and... and nozzle to see if they are clear. Insert charged cartridge. Ensure dry chemical is free flowing...

46 CFR 176.810 - Fire protection.

Code of Federal Regulations, 2014 CFR

2014-10-01

... systems, including sensors and alarms. (b) The owner, managing operator, or a qualified servicing facility... satisfaction of the Coast Guard inspector. Dry chemical (cartridge operated) Examine pressure cartridge and... and nozzle to see if they are clear. Insert charged cartridge. Ensure dry chemical is free flowing...

Neural net controller for inlet pressure control of rocket engine testing

NASA Technical Reports Server (NTRS)

Trevino, Luis C.

1994-01-01

Many dynamic systems operate in select operating regions, each exhibiting characteristic modes of behavior. It is traditional to employ standard adjustable gain proportional-integral-derivative (PID) loops in such systems where no apriori model information is available. However, for controlling inlet pressure for rocket engine testing, problems in fine tuning, disturbance accommodation, and control gains for new profile operating regions (for research and development) are typically encountered. Because of the capability of capturing I/O peculiarities, using NETS, a back propagation trained neural network is specified. For select operating regions, the neural network controller is simulated to be as robust as the PID controller. For a comparative analysis, the higher order moment neural array (HOMNA) method is used to specify a second neural controller by extracting critical exemplars from the I/O data set. Furthermore, using the critical exemplars from the HOMNA method, a third neural controller is developed using NETS back propagation algorithm. All controllers are benchmarked against each other.

Test Rig for Evaluating Active Turbine Blade Tip Clearance Control Concepts

NASA Technical Reports Server (NTRS)

Lattime, Scott B.; Steinetz, Bruce M.; Robbie, Malcolm G.

2003-01-01

Improved blade tip sealing in the high pressure compressor and high pressure turbine can provide dramatic improvements in specific fuel consumption, time-on-wing, compressor stall margin and engine efficiency as well as increased payload and mission range capabilities of both military and commercial gas turbine engines. The preliminary design of a mechanically actuated active clearance control (ACC) system for turbine blade tip clearance management is presented along with the design of a bench top test rig in which the system is to be evaluated. The ACC system utilizes mechanically actuated seal carrier segments and clearance measurement feedback to provide fast and precise active clearance control throughout engine operation. The purpose of this active clearance control system is to improve upon current case cooling methods. These systems have relatively slow response and do not use clearance measurement, thereby forcing cold build clearances to set the minimum clearances at extreme operating conditions (e.g., takeoff, re-burst) and not allowing cruise clearances to be minimized due to the possibility of throttle transients (e.g., step change in altitude). The active turbine blade tip clearance control system design presented herein will be evaluated to ensure that proper response and positional accuracy is achievable under simulated high-pressure turbine conditions. The test rig will simulate proper seal carrier pressure and temperature loading as well as the magnitudes and rates of blade tip clearance changes of an actual gas turbine engine. The results of these evaluations will be presented in future works.

Review of a Metdology for Tracking the Neutron Exposure of Pwr Pressure Vessels during the License Renewal Period

NASA Astrophysics Data System (ADS)

Anderson, Stan L.; Fero, Arnold H.; Roberts, George K.

2003-06-01

The neutron fluence associated with each material in the pressure vessel beltline region is determined on a plant specific basis at each surveillance capsule withdrawal. Based on an assumed mode of operation, fluence projections to account for future operation are then made for use in vessel integrity evaluations. The applicability of these assumed projections is normally verified and updated, if necessary, at each subsequent surveillance capsule withdrawal. However, following the last scheduled withdrawal of a surveillance capsule, there is generally no formal mechanism in place to assure that fluence projections for the remainder of plant operating lifetime remain valid. This paper provides a review of a methodology that can be efficiently used in conjunction with future fuel loading patterns or on-line core power distribution monitoring systems to track the actual fluence accrued by each of the pressure vessel beltline materials in the operating period following the last capsule withdrawal.

Development of a Portable Oxygen Monitoring System for Operations in the International Space Station Airlock

NASA Technical Reports Server (NTRS)

Graf, John

2009-01-01

NASA is currently engaged in an activity to facilitate effective operations on the International Space Station (ISS) after the Space Shuttle retires. Currently, the Space Shuttle delivers crew and cargo to and from ISS. The Space Shuttle provides the only large scale method of hardware return from ISS to the ground. Hardware that needs to be periodically repaired, refurbished, or recalibrated must come back from ISS on the Shuttle. One example of NASA flight hardware that is used on ISS and refurbished on the ground is the Compound Specific Analyzer for Oxygen (CSA-O2). The CSA-O2 is an electrochemical sensor that is used on orbit for about 12 months (depending on Shuttle launch schedules), then returned to the ground for sensor replacement. The shuttle is scheduled to retire in 2010, and the ISS is scheduled to operate until 2016. NASA needs a hand held sensor that measures oxygen in the ISS environment and has a 5-10 year service life. After conducting a survey of oxygen sensor systems, NASA selected a Tunable Diode Laser Absorption Spectrometer (TDLAS) as the method of measurement that best addresses the needs for ISS. These systems are compact, meet ISS accuracy requirements, and because they use spectroscopic techniques, the sensors are not consumed or altered after making a measurement. TDLAS systems have service life ratings of 5-10 years, based on the lifetime of the laser. NASA is engaged in modifying a commercially available sensor, the Vaisala OMT 355, for the ISS application. The Vaisala OMT 355 requires three significant modifications to meet ISS needs. The commercial sensor uses a wall mount power supply, and the ISS sensor needs to use a rechargeable battery as its source of power. The commercial sensor has a pressure correction setpoint: the sensor can be adjusted to operate at reduced pressure conditions, but the sensor does not self correct dynamically and automatically. The ISS sensor needs to operate in the airlock, and make accurate measurements in an environment that can change from 14.7 psia to 10.2 psia in 15 minutes. The commercial sensor needs to be repackaged into a configuration that is more compact, and better suited for ISS airlock operations. NASA has recently completed a prototype of the reconfigured system. The unit has been repackaged in a way that the optical path of the spectrometer is unchanged, but the electronics has been integrated into a case measuring 10.7 X 7.2 X 3.0 inches. Two flight qualified rechargeable batteries have been integrated into system. The batteries can power the sensor for 10 hours on a single charge. A pressure sensor has been added to the system. The modified unit automatically compensates for changes in pressure, and meets 0.2% accuracy requirements for oxygen measurements in an environment with 18 to 32% oxygen across a pressure range of 10.0 to 15.0 psia.

On the possibility of connecting a non-operating main circulation pump with three pumps in operation without preliminary coast-down of power-generating unit No. 5 in the Novovoronezh nuclear power plant

NASA Astrophysics Data System (ADS)

Vitkovskii, I. L.; Nikonov, S. P.; Ryasnyi, S. I.

2014-02-01

The subject of this paper is a transient caused by connection of a standby loop to three operating circulation pumps at the initial reactor heat rate equal to 70% of the rated value without preliminarily reducing it to 30% of the rated level as required by the safe operation regulations. Failure of the following normal operation systems is supposed: the first- and the second-type warning protection systems, all quick-acting reducing devices releasing steam into the auxiliary manifold, the electric heaters of the pressurizer, the pressurizer injection system, the primary cooling circuit fluid makeup/blow-through systems, and the blocking systems to shut down the main circulation pump after the level in the steam generator is exceeded. In addition, it is supposed that, under transient conditions, the valves of the turbine regulation system will be in the position in which they were at the moment of the initial event until generation of the signal for positive closing of the turbine stop valves. The first signal to actuate the reactor emergency protection system (EPS) is skipped. The failure of all quick-acting reducing devices releasing steam into the atmosphere is assumed. In addition to equipment failure, at the moment when the main circulation pump is connected, the operator erroneously puts in a new setting to maintain the power allowable for four pumps in operation-in the calculations it was taken equal to 104% of the rated level at most considering the accuracy of evaluating and maintaining the reactor heat rate-and the working group of the reactor protection and control system (P&CS) starts moving upward. On reaching the set power level, the automatic reactor power regulator stops operating and the P&CS elements remain in the position in which they are at the moment. Compliance with the design safety criteria for the adopted scenario of the transient is demonstrated.

Wireless Capacitive Pressure Sensor With Directional RF Chip Antenna for High Temperature Environments

NASA Technical Reports Server (NTRS)

Scardelletti, M. C.; Jordan, J. L.; Ponchak, G. E.; Zorman, C. A.

2015-01-01

This paper presents the design, fabrication and characterization of a wireless capacitive pressure sensor with directional RF chip antenna that is envisioned for the health monitoring of aircraft engines operating in harsh environments. The sensing system is characterized from room temperature (25 C) to 300 C for a pressure range from 0 to 100 psi. The wireless pressure system consists of a Clapp-type oscillator design with a capacitive MEMS pressure sensor located in the LC-tank circuit of the oscillator. Therefore, as the pressure of the aircraft engine changes, so does the output resonant frequency of the sensing system. A chip antenna is integrated to transmit the system output to a receive antenna 10 m away.The design frequency of the wireless pressure sensor is 127 MHz and a 2 increase in resonant frequency over the temperature range of 25 to 300 C from 0 to 100 psi is observed. The phase noise is less than minus 30 dBcHz at the 1 kHz offset and decreases to less than minus 80 dBcHz at 10 kHz over the entire temperature range. The RF radiation patterns for two cuts of the wireless system have been measured and show that the system is highly directional and the MEMS pressure sensor is extremely linear from 0 to 100 psi.

Inertial motion capture system for biomechanical analysis in pressure suits

NASA Astrophysics Data System (ADS)

Di Capua, Massimiliano

A non-invasive system has been developed at the University of Maryland Space System Laboratory with the goal of providing a new capability for quantifying the motion of the human inside a space suit. Based on an array of six microprocessors and eighteen microelectromechanical (MEMS) inertial measurement units (IMUs), the Body Pose Measurement System (BPMS) allows the monitoring of the kinematics of the suit occupant in an unobtrusive, self-contained, lightweight and compact fashion, without requiring any external equipment such as those necessary with modern optical motion capture systems. BPMS measures and stores the accelerations, angular rates and magnetic fields acting upon each IMU, which are mounted on the head, torso, and each segment of each limb. In order to convert the raw data into a more useful form, such as a set of body segment angles quantifying pose and motion, a series of geometrical models and a non-linear complimentary filter were implemented. The first portion of this works focuses on assessing system performance, which was measured by comparing the BPMS filtered data against rigid body angles measured through an external VICON optical motion capture system. This type of system is the industry standard, and is used here for independent measurement of body pose angles. By comparing the two sets of data, performance metrics such as BPMS system operational conditions, accuracy, and drift were evaluated and correlated against VICON data. After the system and models were verified and their capabilities and limitations assessed, a series of pressure suit evaluations were conducted. Three different pressure suits were used to identify the relationship between usable range of motion and internal suit pressure. In addition to addressing range of motion, a series of exploration tasks were also performed, recorded, and analysed in order to identify different motion patterns and trajectories as suit pressure is increased and overall suit mobility is reduced. The focus of these evaluations was to quantify the reduction in mobility when operating in any of the evaluated pressure suits. This data should be of value in defining new low cost alternatives for pressure suit performance verification and evaluation. This work demonstrates that the BPMS technology is a viable alternative or companion to optical motion capture; while BPMS is the first motion capture system that has been designed specifically to measure the kinematics of a human in a pressure suit, its capabilities are not constrained to just being a measurement tool. The last section of the manuscript is devoted to future possible uses for the system, with a specific focus on pressure suit applications such in the use of BPMS as a master control interface for robot teleoperation, as well as an input interface for future robotically augmented pressure suits.

Screening reactor steam/water piping systems for water hammer

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

Griffith, P.

1997-09-01

A steam/water system possessing a certain combination of thermal, hydraulic and operational states, can, in certain geometries, lead to a steam bubble collapse induced water hammer. These states, operations, and geometries are identified. A procedure that can be used for identifying whether an unbuilt reactor system is prone to water hammer is proposed. For the most common water hammer, steam bubble collapse induced water hammer, six conditions must be met in order for one to occur. These are: (1) the pipe must be almost horizontal; (2) the subcooling must be greater than 20 C; (3) the L/D must be greatermore » than 24; (4) the velocity must be low enough so that the pipe does not run full, i.e., the Froude number must be less than one; (5) there should be void nearby; (6) the pressure must be high enough so that significant damage occurs, that is the pressure should be above 10 atmospheres. Recommendations on how to avoid this kind of water hammer in both the design and the operation of the reactor system are made.« less

Space and Air Force: Rhetoric or Reality

DTIC Science & Technology

1999-04-01

1997, (introduction). 11 Ibid., 18. 12 Ibid., 17. 13 Notes 13 Joint Operations Coursebook , “Joint Strategic Planning System: CJCS Instruction 3100.01...infrastructures as “the physical and information systems essential to the operations of the economy and government.”22 The NSS also specifies, “but...advances in information technology and competitive pressure to improve efficiency and productivity have created new vulnerabilities to both physical