MSFC Combustion Devices in 2001

NASA Technical Reports Server (NTRS)

Dexter, Carol; Turner, James (Technical Monitor)

2001-01-01

The objectives of the project detailed in this viewgraph presentation were to reduce thrust assembly weights to create lighter engines and to increase the cycle life and/or operating temperatures. Information is given on material options (metal matrix composites and polymer matrix composites), ceramic matrix composites subscale liners, lightweight linear chambers, lightweight injector development, liquid/liquid preburner tasks, and vortex chamber tasks.

Composite Nozzle/Thrust Chambers Analyzed for Low-Cost Boosters

NASA Technical Reports Server (NTRS)

Sullivan, Roy M.

1999-01-01

The Low Cost Booster Technology Program is an initiative to minimize the cost of future liquid engines by using advanced materials and innovative designs, and by reducing engine complexity. NASA Marshall Space Flight Center s 60K FASTRAC Engine is one example where these design philosophies have been put into practice. This engine burns a liquid kerosene/oxygen mixture. It uses a one-piece, polymer composite thrust chamber/nozzle that is constructed of a tape-wrapped silica phenolic liner, a metallic injector interface ring, and a filament-wound epoxy overwrap. A cooperative effort between NASA Lewis Research Center s Structures Division and Marshall is underway to perform a finite element analysis of the FASTRAC chamber/nozzle under all the loading and environmental conditions that it will experience during its lifetime. The chamber/nozzle is a complex composite structure. Of its three different materials, the two composite components have distinctly different fiber architectures and, consequently, require separate material model descriptions. Since the liner is tape wrapped, it is orthotropic in the nozzle global coordinates; and since the overwrap is filament wound, it is treated as a monoclinic material. Furthermore, the wind angle on the overwrap varies continuously along the length of the chamber/nozzle.

Advanced composite combustor structural concepts program

NASA Technical Reports Server (NTRS)

Sattar, M. A.; Lohmann, R. P.

1984-01-01

An analytical study was conducted to assess the feasibility of and benefits derived from the use of high temperature composite materials in aircraft turbine engine combustor liners. The study included a survey and screening of the properties of three candidate composite materials including tungsten reinforced superalloys, carbon-carbon and silicon carbide (SiC) fibers reinforcing a ceramic matrix of lithium aluminosilicate (LAS). The SiC-LAS material was selected as offering the greatest near term potential primarily on the basis of high temperature capability. A limited experimental investigation was conducted to quantify some of the more critical mechanical properties of the SiC-LAS composite having a multidirection 0/45/-45/90 deg fiber orientation favored for the combustor linear application. Rigorous cyclic thermal tests demonstrated that SiC-LAS was extremely resistant to the thermal fatigue mechanisms that usually limit the life of metallic combustor liners. A thermal design study led to the definition of a composite liner concept that incorporated film cooled SiC-LAS shingles mounted on a Hastelloy X shell. With coolant fluxes consistent with the most advanced metallic liner technology, the calculated hot surface temperatures of the shingles were within the apparent near term capability of the material. Structural analyses indicated that the stresses in the composite panels were low, primarily because of the low coefficient of expansion of the material and it was concluded that the dominant failure mode of the liner would be an as yet unidentified deterioration of the composite from prolonged exposure to high temperature. An economic study, based on a medium thrust size commercial aircraft engine, indicated that the SiC-LAS combustor liner would weigh 22.8N (11.27 lb) less and cost less to manufacture than advanced metallic liner concepts intended for use in the late 1980's.

Fabrication of High Thermal Conductivity NARloy-Z-Diamond Composite Combustion Chamber Liner for Advanced Rocket Engines

NASA Technical Reports Server (NTRS)

Bhat, Biliyar N.; Greene, Sandra E.; Singh, Jogender

2016-01-01

NARloy-Z alloy (Cu-3 percent, Ag-0.5 percent, Zr) is a state of the art alloy currently used for fabricating rocket engine combustion chamber liners. Research conducted at NASA-MSFC and Penn State – Applied Research Laboratory has shown that thermal conductivity of NARloy-Z can be increased significantly by adding diamonds to form a composite (NARloy-Z-D). NARloy-Z-D is also lighter than NARloy-Z. These attributes make this advanced composite material an ideal candidate for fabricating combustion chamber liner for an advanced rocket engine. Increased thermal conductivity will directly translate into increased turbopump power and increased chamber pressure for improved thrust and specific impulse. This paper describes the process development for fabricating a subscale high thermal conductivity NARloy-Z-D combustion chamber liner using Field Assisted Sintering Technology (FAST). The FAST process uses a mixture of NARloy-Z and diamond powders which is sintered under pressure at elevated temperatures. Several challenges were encountered, i.e., segregation of diamonds, machining the super hard NARloy-Z-D composite, net shape fabrication and nondestructive examination. The paper describes how these challenges were addressed. Diamonds coated with copper (CuD) appear to give the best results. A near net shape subscale combustion chamber liner is being fabricated by diffusion bonding cylindrical rings of NARloy-Z-CuD using the FAST process.

High-Energy Space Propulsion Based on Magnetized Target Fusion

NASA Technical Reports Server (NTRS)

Thio, Y. C. F.; Freeze, B.; Kirkpatrick, R. C.; Landrum, B.; Gerrish, H.; Schmidt, G. R.

1999-01-01

A conceptual study is made to explore the feasibility of applying magnetized target fusion (MTF) to space propulsion for omniplanetary travel. Plasma-jet driven MTF not only is highly amenable to space propulsion, but also has a number of very attractive features for this application: 1) The pulsed fusion scheme provides in situ a very dense hydrogenous liner capable of moderating the neutrons, converting more than 97% of the neutron energy into charged particle energy of the fusion plasma available for propulsion. 2) The fusion yield per pulse can be maintained at an attractively low level (< 1 GJ) despite a respectable gain in excess of 70. A compact, low-weight engine is the result. An engine with a jet power of 25 GW, a thrust of 66 kN, and a specific impulse of 77,000 s, can be achieved with an overall engine mass of about 41 metric tons, with a specific power density of 605 kW/kg, and a specific thrust density of 1.6 N/kg. The engine is rep-rated at 40 Hz to provide this power and thrust level. At a practical rep-rate limit of 200 Hz, the engine can deliver 128 GW jet power and 340 kN of thrust, at specific power and thrust density of 1,141 kW/kg and 3 N/kg respectively. 3) It is possible to operate the magnetic nozzle as a magnetic flux compression generator in this scheme, while attaining a high nozzle efficiency of 80% in converting the spherically radial momentum of the fusion plasma to an axial impulse. 4) A small fraction of the electrical energy generated from the flux compression is used directly to recharge the capacitor bank and other energy storage equipment, without the use of a highvoltage DC power supply. A separate electrical generator is not necessary. 5) Due to the simplicity of the electrical circuit and the components, involving mainly inductors, capacitors, and plasma guns, which are connected directly to each other without any intermediate equipment, a high rep-rate (with a maximum of 200 Hz) appears practicable. 6) All fusion related components are within the current state of the art for pulsed power technology. Experimental facilities with the required pulsed power capabilities already exist. 7) The scheme does not require prefabricated fuel target and liner hardware in any esoteric form or state. All necessary fuel and liner material are introduced into the engine in the form of ordinary matter in gaseous state at room temperature, greatly simplifying their handling on board. They are delivered into the fusion reaction chamber in a completely standoff manner.

High Thermal Conductivity NARloy-Z-Diamond Composite Combustion Chamber Liner For Advanced Rocket Engines

NASA Technical Reports Server (NTRS)

Bhat, Biliyar N.; Ellis, David; Singh, Jogender

2014-01-01

Advanced high thermal conductivity materials research conducted at NASA Marshall Space Flight Center (MSFC) with state of the art combustion chamber liner material NARloy-Z showed that its thermal conductivity can be increased significantly by adding diamond particles and sintering it at high temperatures. For instance, NARloy-Z containing 40 vol. percent diamond particles, sintered at 975C to full density by using the Field assisted Sintering Technology (FAST) showed 69 percent higher thermal conductivity than baseline NARloy-Z. Furthermore, NARloy-Z-40vol. percent D is 30 percent lighter than NARloy-Z and hence the density normalized thermal conductivity is 140 percent better. These attributes will improve the performance and life of the advanced rocket engines significantly. By one estimate, increased thermal conductivity will directly translate into increased turbopump power up to 2X and increased chamber pressure for improved thrust and ISP, resulting in an expected 20 percent improvement in engine performance. Follow on research is now being conducted to demonstrate the benefits of this high thermal conductivity NARloy-Z-D composite for combustion chamber liner applications in advanced rocket engines. The work consists of a) Optimizing the chemistry and heat treatment for NARloy-Z-D composite, b) Developing design properties (thermal and mechanical) for the optimized NARloy-Z-D, c) Fabrication of net shape subscale combustion chamber liner, and d) Hot fire testing of the liner for performance. FAST is used for consolidating and sintering NARlo-Z-D. The subscale cylindrical liner with built in channels for coolant flow is also fabricated near net shape using the FAST process. The liner will be assembled into a test rig and hot fire tested in the MSFC test facility to determine performance. This paper describes the development of this novel high thermal conductivity NARloy-Z-D composite material, and the advanced net shape technology to fabricate the combustion chamber liner. Properties of optimized NARloy-Z-D composite material will also be presented.

FY98 Aero Propulsion & Power Technology Area Plan.

DTIC Science & Technology

1997-11-01

controlled area turbine nozzle (HPT & LPT) - second quarter FY98 a Fabrication/test of gamma titanium aluminide exhaust flap/liner - third quarter...both a commercial business jet and an unmanned air vehicle (Dark Star). - "Super-cooled" turbine blade designs permit 3000 F higher gas temperature for...increased thrust, or 30% reduction in blade cooling air for reduced fuel consumption, or two-to four- fold increase in turbine blade life - all at a

Fabrication of High Thermal Conductivity NARloy-Z-Diamond Composite Combustion Chamber Liner for Advanced Rocket Engines

NASA Technical Reports Server (NTRS)

Bhat, Biliyar N.; Greene, Sandra E.; Singh, Jogender

2016-01-01

This paper describes the process development for fabricating a high thermal conductivity NARloy-Z-Diamond composite (NARloy-Z-D) combustion chamber liner for application in advanced rocket engines. The fabrication process is challenging and this paper presents some details of these challenges and approaches used to address them. Prior research conducted at NASA-MSFC and Penn State had shown that NARloy-Z-40%D composite material has significantly higher thermal conductivity than the state of the art NARloy-Z alloy. Furthermore, NARloy-Z-40 %D is much lighter than NARloy-Z. These attributes help to improve the performance of the advanced rocket engines. Increased thermal conductivity will directly translate into increased turbopump power, increased chamber pressure for improved thrust and specific impulse. Early work on NARloy-Z-D composites used the Field Assisted Sintering Technology (FAST, Ref. 1, 2) for fabricating discs. NARloy-Z-D composites containing 10, 20 and 40vol% of high thermal conductivity diamond powder were investigated. Thermal conductivity (TC) data. TC increased with increasing diamond content and showed 50% improvement over pure copper at 40vol% diamond. This composition was selected for fabricating the combustion chamber liner using the FAST technique.

A 1/10 Scale Model Test of a Fixed Chute Mixer-Ejector Nozzle in Unsuppressed Model. Part 1; Test Overview

NASA Technical Reports Server (NTRS)

Wolter, John D.

2007-01-01

This paper discusses a test of a nozzle concept for a high-speed commercial aircraft. While a great deal of effort has been expended to und erstand the noise-suppressed, take-off performance of mixer-ejector n ozzles, little has been done to assess their performance in unsuppressed mode at other flight conditions. To address this, a 1/10th scale m odel mixer-ejector nozzle in unsuppressed mode was tested at conditio ns representing transonic acceleration, supersonic cruise, subsonic cruise, and approach. Various configurations were tested to understand the effects of acoustic liners and several geometric parameters, such as throat area, expansion ratio, and nozzle length on nozzle performance. Thrust, flow, and internal pressures were measured. A statistica l model of the peak thrust coefficient results is presented and discussed.

High-Pressure Lightweight Thrusters

NASA Technical Reports Server (NTRS)

Holmes, Richard; McKechnie, Timothy; Shchetkovskiy, Anatoliy; Smirnov, Alexander

2013-01-01

Returning samples of Martian soil and rock to Earth is of great interest to scientists. There were numerous studies to evaluate Mars Sample Return (MSR) mission architectures, technology needs, development plans, and requirements. The largest propulsion risk element of the MSR mission is the Mars Ascent Vehicle (MAV). Along with the baseline solid-propellant vehicle, liquid propellants have been considered. Similar requirements apply to other lander ascent engines and reaction control systems. The performance of current state-ofthe- art liquid propellant engines can be significantly improved by increasing both combustion temperature and pressure. Pump-fed propulsion is suggested for a single-stage bipropellant MAV. Achieving a 90-percent stage propellant fraction is thought to be possible on a 100-kg scale, including sufficient thrust for lifting off Mars. To increase the performance of storable bipropellant rocket engines, a high-pressure, lightweight combustion chamber was designed. Iridium liner electrodeposition was investigated on complex-shaped thrust chamber mandrels. Dense, uniform iridium liners were produced on chamber and cylindrical mandrels. Carbon/carbon composite (C/C) structures were braided over iridium-lined mandrels and densified by chemical vapor infiltration. Niobium deposition was evaluated for forming a metallic attachment flange on the carbon/ carbon structure. The new thrust chamber was designed to exceed state-of-the-art performance, and was manufactured with an 83-percent weight savings. High-performance C/Cs possess a unique set of properties that make them desirable materials for high-temperature structures used in rocket propulsion components, hypersonic vehicles, and aircraft brakes. In particular, more attention is focused on 3D braided C/Cs due to their mesh-work structure. Research on the properties of C/Cs has shown that the strength of composites is strongly affected by the fiber-matrix interfacial bonding, and that weakening interface realizes pseudo-plastic behavior with significant increase in the tensile strength. The investigation of high-temperature strength of C/Cs under high-rate heating (critical for thrust chambers) shows that tensile and compression strength increases from 70 MPa at room temperature to 110 MPa at 1,773 K, and up to 125 MPa at 2,473 K. Despite these unique properties, the use of C/Cs is limited by its high oxidation rate at elevated temperatures. Lining carbon/carbon chambers with a thin layer of iridium or iridium and rhenium is an innovative way to use proven refractory metals and provide the oxidation barrier necessary to enable the use of carbon/ carbon composites. Due to the lower density of C/Cs as compared to SiC/SiC composites, an iridium liner can be added to the C/C structure and still be below the overall thruster weight. Weight calculations show that C/C, C/C with 50 microns of Ir, and C/C with 100 microns of Ir are of less weight than alternative materials for the same construction.

Fusion Ignition Rocket Engine with Ballistic Ablative Lithium Liner

NASA Technical Reports Server (NTRS)

Martin, Adam; Eskridge, Richard; Fimognari, Peter J., III.

2005-01-01

Thermo-nuclear fusion may be the key to a high Isp, high specific power (low alpha) propulsion system. In a fusion system energy is liberated within, and imparted directly to, the propellant. In principle, this can overcome the performance limitations inherent in systems that require thermal power transfer across a material boundary, and/or multiple power conversion stages (NTR, NEP). A thermo-nuclear propulsion system, which attempts to overcome some of the problems inherent in the ORION concept, is described. A passive tapered liner is launched behind a vehicle, through a hole in a pusher-plate, that is connected to the vehicle by a shock-absorbing mechanism. A dense FRC plasmoid is then accelerated to high velocity (in excess of 1,000 km/s) and shot through the hole into the liner, when it has reached a given point down-range. The kinetic energy of the FRC is converted into thermal and magnetic-field energy, igniting a fusion bum in the magnetically confined plasma. The fusion reaction serves as an ignition source for the liner, which is made out of detonable materials. The energy liberated in this process is converted to thrust by the pusher-plate, as in the classic ORION concept. However with this concept, the vehicle does not carry a magazine of pre-fabricated pulse-units. A magnetic nozzle may also be used, in place of the pusher-plate. Estimates of the conditions needed to achieve a sufficient gain will be presented, along with a description of the driver characteristics. The incorporation of this concept into the propulsion system of a spacecraft will also be discussed.

Conventionally cast and forged copper alloy for high-heat-flux thrust chambers

NASA Technical Reports Server (NTRS)

Kazaroff, John M.; Repas, George A.

1987-01-01

The combustion chamber liner of the space shuttle main engine is made of NARloy-Z, a copper-silver-zirconium alloy. This alloy was produced by vacuum melting and vacuum centrifugal casting; a production method that is currently now available. Using conventional melting, casting, and forging methods, NASA has produced an alloy of the same composition called NASA-Z. This report compares the composition, microstructure, tensile properties, low-cycle fatigue life, and hot-firing life of these two materials. The results show that the materials have similar characteristics.

Aluminum low temperature smelting cell metal collection

DOEpatents

Beck, Theodore R.; Brown, Craig W.

2002-07-16

A method of producing aluminum in an electrolytic cell containing alumina dissolved in an electrolyte. The method comprises the steps of providing a molten salt electrolyte in an electrolytic cell having an anodic liner for containing the electrolyte, the liner having an anodic bottom and walls including at least one end wall extending upwardly from the anodic bottom, the anodic liner being substantially inert with respect to the molten electrolyte. A plurality of non-consumable anodes is provided and disposed vertically in the electrolyte. A plurality of cathodes is disposed vertically in the electrolyte in alternating relationship with the anodes. The anodes are electrically connected to the anodic liner. An electric current is passed through the anodic liner to the anodes, through the electrolyte to the cathodes, and aluminum is deposited on said cathodes. Oxygen bubbles are generated at the anodes and the anodic liner, the bubbles stirring the electrolyte. Molten aluminum is collected from the cathodes into a tubular member positioned underneath the cathodes. The tubular member is in liquid communication with each cathode to collect the molten aluminum therefrom while excluding electrolyte. Molten aluminum is delivered through the tubular member to a molten aluminum reservoir located substantially opposite the anodes and cathodes. The molten aluminum is collected from the cathodes and delivered to the reservoir while avoiding contact of the molten aluminum with the anodic bottom.

Nanoscale CuO solid-electrolyte-based conductive-bridging, random-access memory cell with a TiN liner

NASA Astrophysics Data System (ADS)

Lee, Jong-Sun; Kim, Dong-Won; Kim, Hea-Jee; Jin, Soo-Min; Song, Myung-Jin; Kwon, Ki-Hyun; Park, Jea-Gun; Jalalah, Mohammed; Al-Hajry, Ali

2018-01-01

The Conductive-bridge random-access memory (CBRAM) cell is a promising candidate for a terabit-level non-volatile memory due to its remarkable advantages. We present for the first time TiN as a diffusion barrier in CBRAM cells for enhancing their reliability. CuO solid-electrolyte-based CBRAM cells implemented with a 0.1-nm TiN liner demonstrated better non-volatile memory characteristics such as 106 AC write/erase endurance cycles with 100-μs AC pulse width and a long retention time of 7.4-years at 85 °C. In addition, the analysis of Ag diffusion in the CBRAM cell suggests that the morphology of the Ag filaments in the electrolyte can be effectively controlled by tuning the thickness of the TiN liner. These promising results pave the way for faster commercialization of terabit-level non-volatile memories.

Long-term efficacy of denture cleansers in preventing Candida spp. biofilm recolonization on liner surface.

PubMed

Vieira, Ana Paula Coelho; Senna, Plínio Mendes; Silva, Wander José da; Del Bel Cury, Altair Antoninha

2010-01-01

This study evaluated the long-term efficacy of denture cleansers against Candida spp. biofilm recolonization on liner surface. Specimens were fabricated of a poly(methyl methacrylate)-based denture liner and had their surface roughness evaluated at baseline and after cleansing treatments. C. albicans or C. glabrata biofilms were formed on liner surface for 48 h, and then the specimens were randomly assigned to one of cleaning treatments: two alkaline peroxides (soaking for 3 or 15 min), 0.5% sodium hypochlorite (10 min) or distilled water (control; 15 min). After the treatments, the specimens were sonicated to disrupt the biofilm, and residual cells were counted (cell/mL). Long-term effectiveness of the cleaning processes was determined by submitting a set of cleaned specimens to biofilm growth conditions for 48 h followed by estimation of cell counts. The topography of specimens after cleaning treatments was analyzed by SEM. Data were analyzed by ANOVA and Tukey's test (α; = 0.05). Results of cell count estimation showed significant differences in cleanliness among the treatments (p < 0.001), and it could be observed by SEM. However, no significant difference (p > 0.05) was observed among the Candida species regarding the recolonization condition. Alkaline denture cleansers showed similar cleaning performance and both differed from the control (p < 0.001). Sodium hypochlorite was the only treatment that removed biofilm efficiently, since no viable cells were found after its use. In conclusion, alkaline peroxide denture cleansers were not effective in removing Candida spp. biofilm from denture liner surfaces and preventing biofilm recolonization.

Hydrocarbon-fuel/copper combustion chamber liner compatibility, corrosion prevention, and refurbishment

NASA Technical Reports Server (NTRS)

Rosenberg, S. D.; Gage, M. L.; Homer, G. D.; Franklin, J. E.

1991-01-01

An evaluation is made of combustion product/combustion chamber compatibility in the case of a LOX/liquid hydrocarbon booster engine based on copper-alloy thrust chamber which is regeneratively cooled by the fuel. It is found that sulfur impurities in the fuel are the primary causes of copper corrosion, through formation of Cu2S; sulfur levels as low as 1 ppm can result in sufficiently severe copper corrosion to degrade cooling channel performance. This corrosion can be completely eliminated, however, through the incorporation of an electrodeposited gold coating on the copper cooling-channel walls.

Approaches to consider covers and liners in a low-level waste disposal facility performance assessment

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

Seitz, Roger; Phifer, Mark; Suttora, Linda

2015-03-17

On-site disposal cells are in use and being considered at several USDOE sites as the final disposition for large amounts of waste associated with cleanup of contaminated areas and facilities. These disposal cells are typically regulated by States and/or the USEPA in addition to having to comply with requirements in DOE Order 435.1, Radioactive Waste Management. The USDOE-EM Office of Site Restoration formed a working group to foster improved communication and sharing of information for personnel associated with these Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) disposal cells and work towards more consistent assumptions, as appropriate, for technical andmore » policy considerations related to performance and risk assessments in support of a Record of Decision and Disposal Authorization Statement. One task completed by the working group addressed approaches for considering the performance of covers and liners/leachate collection systems in the context of a performance assessment (PA). A document has been prepared which provides recommendations for a general approach to address covers and liners/leachate collection systems in a PA and how to integrate assessments with defense-in-depth considerations such as design, operations and waste acceptance criteria to address uncertainties. Specific information and references are provided for details needed to address the evolution of individual components of cover and liner/leachate collection systems. This information is then synthesized into recommendations for best practices for cover and liner system design and examples of approaches to address the performance of covers and liners as part of a performance assessment of the disposal system.« less

High Temperature, Long Service Life Fuel Cell Bladder Materials

DTIC Science & Technology

2004-03-01

50 Table 19. Inner Liner Rubber , D471 Results – Fluid Aging in JP8+100 @ 225°F............................. 52 Table 20. Inner Liner Rubber ...Tensile Properties – Fluid Aging in JP8+100 @ 225°F ..................... 52 Table 21. Inner Liner Rubber , Tear Properties – Fluid Aging in JP8+100...samples in accordance with ASTM D 471: Test Method for Rubber Property - Effects of Liquids. Fluid aging experiments were performed in friction

Experimental fatigue life investigation of cylindrical thrust chambers

NASA Technical Reports Server (NTRS)

Quentmeyer, R. J.

1977-01-01

Twenty-two cylindrical test sections of a cylindrical rocket thrust chamber were fabricated and 21 of them were cycled to failure to explore the failure mechanisms, determine the effects of wall temperature on cyclic life, and to rank the material life characteristics for comparison with results from isothermal tests of 12 alloys at 538 C. Cylinder liners were fabricated from OFHC copper, Amzirc, and NAR1loy-Z. Tests were conducted at a chamber pressure of 4.14 MW/sq m using hydrogen-oxygen propellants at an oxidant-fuel ratio of 6.0, which resulted in an average throat heat flux of 54 MW/sq m. The cylinders were cooled with liquid hydrogen at an average rate of 0.91 Kg/sec. All failures were characterized by a thinning of the cooling channel wall at the centerline and eventual failure by tensile rupture. Cyclic life rankings of the materials based on temperature do not agree with published rankings based on uniaxial, isothermal strain tests.

Estimating surface temperature in forced convection nucleate boiling: A simplified method

NASA Technical Reports Server (NTRS)

Hendricks, R. C.; Papell, S. S.

1977-01-01

During a test program to investigate low-cycle thermal fatigue, 21 of 22 cylindrical test sections of a cylindrical rocket thrust chamber were thermally cycled to failure. Cylinder liners were fabricated from OFHC copper, Amzirc, and NARloy-Z. The cylinders were fabricated by milling cooling channels into the liner and closing out the backside with electrodeposited copper. The tests were conducted at a chamber pressure of 4.14 MN/sq m (600 psia) and an oxidant-fuel ratio of 6.0 using hydrogen-oxygen as propellants. The average throat heat flux was 54 MW/sq m (33 Btu/sq in./sec). All of the failures were characterized by a thinning of the cooling channel wall and eventual failure by tensile rupture. The 1/2-hard Amzirc material showed little improvement in cyclic life when compared with OFHC copper; while the NARloy-Z and aged Amzirc materials had the best cyclic life characteristics. One OFHC copper cylinder was thermall cycled 2044 times at a steady-state hot-gas-side wall temperature of 514 K (925 R) without failing.

Thermal Barrier and Protective Coatings to Improve the Durability of a Combustor Under a Pulse Detonation Engine Environment

NASA Technical Reports Server (NTRS)

Ghosn, Louis J.; Zhu, Dongming

2008-01-01

Pulse detonation engine (PDE) concepts are receiving increasing attention for future aeronautic propulsion applications, due to their potential thermodynamic cycle efficiency and higher thrust to density ratio that lead to the decrease in fuel consumption. But the resulting high gas temperature and pressure fluctuation distributions at high frequency generated with every detonation are viewed to be detrimental to the combustor liner material. Experimental studies on a typical metal combustion material exposed to a laser simulated pulse heating showed extensive surface cracking. Coating of the combustor materials with low thermal conductivity ceramics is shown to protect the metal substrate, reduce the thermal stresses, and hence increase the durability of the PDE combustor liner material. Furthermore, the temperature fluctuation and depth of penetration is observed to decrease with increasing the detonation frequency. A crack propagation rate in the coating is deduced by monitoring the variation of the coating apparent thermal conductivity with time that can be utilized as a health monitoring technique for the coating system under a rapid fluctuating heat flux.

Construction, Startup and Operation of a New LLRW Disposal Facility in Andrews County, Texas - 12151

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

Van Vliet, James A.

2012-07-01

During this last year, Waste Control Specialists LLC (WCS) completed construction and achieved start of operations of a new low level radioactive waste (LLRW) disposal facility in Andrews County Texas. Disposal operations are underway for commercial LLRW, and start up evolutions are in progress for disposal of Department of Energy (DOE) LLRW. The overall approach to construction and start up are presented as well as some of the more significant challenges and how they were addressed to achieve initial operations of the first new commercial low level radioactive waste disposal facility in more than 30 years. The WCS disposal facilitymore » consists of two LLRW disposal cells, one for Texas Compact waste, and a separate disposal cell for DOE waste. Both disposal cells have very robust and unique designs. The cells themselves are constructed entirely in very low permeability red bed clay. The cell liners include a 0.91 meter thick clay liner meeting unprecedented permeability limits, 0.3 meter thick reinforced concrete barriers, as well as the standard geo-synthetic liners. Actions taken to meet performance criteria and install these liners will be discussed. Consistent with this highly protective landfill design, WCS chose to install a zero discharge site water management system. The considerations behind the design and construction of this system will be presented. Other activities essential to successful start of LLRW disposal operations included process and procedure development and refinement, staffing and staff development, and training. Mock ups were built and used for important evolutions and functions. Consistent with the extensive regulation of LLRW operations, engagement with the Texas Commission on Environmental Quality (TCEQ) was continuous and highly interactive. This included daily activity conference calls, weekly coordination calls and numerous topical conference calls and meetings. TCEQ staff and consultants frequently observed specific construction evolutions, such as geological feature mapping of designated excavation faces, disposal cell clay liner installation, disposal cell concrete barrier construction, etc. (author)« less

Liner collection cone and pH effects on postthaw motility, staining, and acrosomes of bovine spermatozoa.

PubMed

Smith, J F; Merilan, C P

1991-04-01

Sixteen ejaculates were collected, four each from four bulls, using artificial vaginas with polyethylene or rubber liner collection cones in a crossover design experiment. The ejaculates were diluted with egg yolk-citrate extender at pH 6.4 or 7.2, cooled, glycerolated, equilibrated, packaged in .5-ml French straws, frozen in nitrogen vapor, and stored in liquid nitrogen. Thirty frozen straws from each ejaculate were thawed rapidly (46.5 degrees C for 12 s), pooled, and then incubated at 46.5 degrees C for periodic evaluation of progressive motility, differential staining, and acrosome morphology under thermal stress conditions. The postthaw motility of spermatozoa and percentage of unstained cells were higher both when collected in polyethylene than in rubber and when extended at pH 7.2 vs. 6.4, but no interaction was found between liner collection cone composition and pII for postthaw motility. Retention of spermatozoan motility during incubation under thermal stress was greater for cells collected in polyethylene, but not different due to pH. Neither pH nor composition of liner collection cone had an effect on postthaw acrosomal scores, but the time required for a 50% increase in severely damaged acrosomes was greater for spermatozoa collected in polyethylene than in rubber liner collection cones.

Lightweight bladder lined pressure vessels

DOEpatents

Mitlitsky, Fred; Myers, Blake; Magnotta, Frank

1998-01-01

A lightweight, low permeability liner for graphite epoxy composite compressed gas storage vessels. The liner is composed of polymers that may or may not be coated with a thin layer of a low permeability material, such as silver, gold, or aluminum, deposited on a thin polymeric layer or substrate which is formed into a closed bladder using torispherical or near torispherical end caps, with or without bosses therein, about which a high strength to weight material, such as graphite epoxy composite shell, is formed to withstand the storage pressure forces. The polymeric substrate may be laminated on one or both sides with additional layers of polymeric film. The liner may be formed to a desired configuration using a dissolvable mandrel or by inflation techniques and the edges of the film seamed by heat sealing. The liner may be utilized in most any type of gas storage system, and is particularly applicable for hydrogen, gas mixtures, and oxygen used for vehicles, fuel cells or regenerative fuel cell applications, high altitude solar powered aircraft, hybrid energy storage/propulsion systems, and lunar/Mars space applications, and other applications requiring high cycle life.

Method for forming a bladder for fluid storage vessels

DOEpatents

Mitlitsky, Fred; Myers, Blake; Magnotta, Frank

2000-01-01

A lightweight, low permeability liner for graphite epoxy composite compressed gas storage vessels. The liner is composed of polymers that may or may not be coated with a thin layer of a low permeability material, such as silver, gold, or aluminum, deposited on a thin polymeric layer or substrate which is formed into a closed bladder using torispherical or near torispherical end caps, with or without bosses therein, about which a high strength to weight material, such as graphite epoxy composite shell, is formed to withstand the storage pressure forces. The polymeric substrate may be laminated on one or both sides with additional layers of polymeric film. The liner may be formed to a desired configuration using a dissolvable mandrel or by inflation techniques and the edges of the film seamed by heat sealing. The liner may be utilized in most any type of gas storage system, and is particularly applicable for hydrogen, gas mixtures, and oxygen used for vehicles, fuel cells or regenerative fuel cell applications, high altitude solar powered aircraft, hybrid energy storage/propulsion systems, and lunar/Mars space applications, and other applications requiring high cycle life.

Manufacturing Process Developments for Regeneratively-Cooled Channel Wall Rocket Nozzles

NASA Technical Reports Server (NTRS)

Gradl, Paul; Brandsmeier, Will

2016-01-01

Regeneratively cooled channel wall nozzles incorporate a series of integral coolant channels to contain the coolant to maintain adequate wall temperatures and expand hot gas providing engine thrust and specific impulse. NASA has been evaluating manufacturing techniques targeting large scale channel wall nozzles to support affordability of current and future liquid rocket engine nozzles and thrust chamber assemblies. The development of these large scale manufacturing techniques focus on the liner formation, channel slotting with advanced abrasive water-jet milling techniques and closeout of the coolant channels to replace or augment other cost reduction techniques being evaluated for nozzles. NASA is developing a series of channel closeout techniques including large scale additive manufacturing laser deposition and explosively bonded closeouts. A series of subscale nozzles were completed evaluating these processes. Fabrication of mechanical test and metallography samples, in addition to subscale hardware has focused on Inconel 625, 300 series stainless, aluminum alloys as well as other candidate materials. Evaluations of these techniques are demonstrating potential for significant cost reductions for large scale nozzles and chambers. Hot fire testing is planned using these techniques in the future.

Rapid prototype fabrication processes for high-performance thrust cells

NASA Technical Reports Server (NTRS)

Hunt, K.; Chwiedor, T.; Diab, J.; Williams, R.

1994-01-01

The Thrust Cell Technologies Program (Air Force Phillips Laboratory Contract No. F04611-92-C-0050) is currently being performed by Rocketdyne to demonstrate advanced materials and fabrication technologies which can be utilized to produce low-cost, high-performance thrust cells for launch and space transportation rocket engines. Under Phase 2 of the Thrust Cell Technologies Program (TCTP), rapid prototyping and investment casting techniques are being employed to fabricate a 12,000-lbf thrust class combustion chamber for delivery and hot-fire testing at Phillips Lab. The integrated process of investment casting directly from rapid prototype patterns dramatically reduces design-to-delivery cycle time, and greatly enhances design flexibility over conventionally processed cast or machined parts.

High Temperature Materials for Chemical Propulsion Applications

NASA Technical Reports Server (NTRS)

Elam, Sandra; Hickman, Robert; O'Dell, Scott

2007-01-01

Radiation or passively cooled thrust chambers are used for a variety of chemical propulsion functions including apogee insertion, reaction control for launch vehicles, and primary propulsion for planetary spacecraft. The performance of these thrust chambers is limited by the operating temperature of available materials. Improved oxidation resistance and increased operating temperatures can be achieved with the use of thermal barrier coatings such as zirconium oxide (ZrO2) and hafnium oxide (HfO2). However, previous attempts to include these materials showed cracking and spalling of the oxide layer due to poor bonding. Current research at NASA's Marshall Space Flight Center (MSFC) has generated unique, high temperature material options for in-space thruster designs that are capable of up to 2500 C operating temperatures. The research is focused on fabrication technologies to form low cost Iridium,qF_.henium (Ir/Re) components with a ceramic hot wall created as an integral, functionally graded material (FGM). The goal of this effort is to further de?celop proven technologies for embedding a protective ceramic coating within the Ir/Re liner to form a robust functional gradient material. Current work includes the fabrication and testing of subscale samples to evaluate tensile, creep, thermal cyclic/oxidation, and thermophysical material properties. Larger test articles have also being fabricated and hot-fire tested to demonstrate the materials in prototype thrusters at 1O0 lbf thrust levels.

Acoustic Liner for Turbomachinery Applications

NASA Technical Reports Server (NTRS)

Huff, Dennis L.; Sutliff, Daniel L.; Jones, Michael G.; Hebsur, Mohan G.

2010-01-01

The purpose of this innovation is to reduce aircraft noise in the communities surrounding airports by significantly attenuating the noise generated by the turbomachinery, and enhancing safety by providing a containment barrier for a blade failure. Acoustic liners are used in today's turbofan engines to reduce noise. The amount of noise reduction from an acoustic liner is a function of the treatment area, the liner design, and the material properties, and limited by the constraints of the nacelle or casement design. It is desirable to increase the effective area of the acoustic treatment to increase noise suppression. Modern turbofan engines use wide-chord rotor blades, which means there is considerable treatment area available over the rotor tip. Turbofan engines require containment over the rotors for protection from blade failure. Traditional methods use a material wrap such as Kevlar integrated with rub strips and sometimes metal layers (sandwiches). It is possible to substitute the soft rub-strip material with an open-cell metallic foam that provides noise-reduction benefits and a sacrificial material in the first layer of the containment system. An open-cell foam was evaluated that behaves like a bulk acoustic liner, serves as a tip rub strip, and can be integrated with a rotor containment system. Foams can be integrated with the fan-containment system to provide sufficient safety margins and increased noise attenuation. The major innovation is the integration of the foam with the containment.

Adsorption of oils, heavy metals and dyes by recovered carbon powder from spent pot liner of aluminum smelter plant.

PubMed

Mazumder, B; Devi, Sasmita Rani

2008-07-01

Aluminum smelter plants employ Hall-Heroult electrolysis cells for electrolysis of molten cryolite to recover aluminum metal by electrolysis. These cells use carbon cathode blocks as a lining material inside. At the end of service life of the cells, pot lines are discarded and new carbon blocks are laid for fresh charging. These used carbon cathode blocks, known as spent pot liners, are heavily infested with toxic elements such as fluoride, cyanide, alkali, etc. Therefore, their disposal in open field poses great environmental risk. A simple process has been developed for decontamination of these spent pot liners and to recover its carbon value. The experiments indicated that this carbon, in the form of fine powder (around 20 micron in size) can absorb toxic elements like heavy metals, dyes, oils, etc. to a great extent and thus can be used for mitigating environmental pollution occuring due to various toxic wastes.

Lifecycle Verification of Tank Liner Polymers

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

Anovitz, Lawrence; Smith, Barton

2014-03-01

This report describes a method that was developed for the purpose of assessing the durability of thermoplastic liners used in a Type IV hydrogen storage tank during the tank s expected service life. In the method, a thermoplastic liner specimen is cycled between the maximum and minimum expected working temperatures while it is differentially pressurized with high-pressure hydrogen gas. The number of thermal cycling intervals corresponds to those expected within the tank s design lifetime. At prescribed intervals, hydrogen permeation measurements are done in situ to assess the ability of the liner specimen to maintain its hydrogen barrier properties andmore » to model its permeability over the tank lifetime. Finally, the model is used to assess whether the steady-state leakage rate in the tank could potentially exceed the leakage specification for hydrogen fuel cell passenger vehicles. A durability assessment was performed on a specimen of high-density polyethylene (HDPE) that is in current use as a tank liner. Hydrogen permeation measurements were performed on several additional tank liner polymers as well as novel polymers proposed for use as storage tank liners and hydrogen barrier materials. The following technical barriers from the Fuel Cell Technologies Program MYRDD were addressed by the project: D. Durability of on-board storage systems lifetime of at least 1500 cycles G. Materials of construction vessel containment that is resistant to hydrogen permeation M. Lack of Tank Performance Data and Understanding of Failure Mechanisms And the following technical targets1 for on-board hydrogen storage systems R&D were likewise addressed: Operational cycle life (1/4 tank to full) FY 2017: 1500 cycles; Ultimate: 1500 cycles Environmental health & safety Permeation and leakage: Meets or exceeds applicable standards Loss of useable H2: FY 2017: 0.05 g/h/kg H2; Ultimate: 0.05 g/h/kg H2« less

Lightweight bladder lined pressure vessels

DOEpatents

Mitlitsky, F.; Myers, B.; Magnotta, F.

1998-08-25

A lightweight, low permeability liner is described for graphite epoxy composite compressed gas storage vessels. The liner is composed of polymers that may or may not be coated with a thin layer of a low permeability material, such as silver, gold, or aluminum, deposited on a thin polymeric layer or substrate which is formed into a closed bladder using tori spherical or near tori spherical end caps, with or without bosses therein, about which a high strength to weight material, such as graphite epoxy composite shell, is formed to withstand the storage pressure forces. The polymeric substrate may be laminated on one or both sides with additional layers of polymeric film. The liner may be formed to a desired configuration using a dissolvable mandrel or by inflation techniques and the edges of the film sealed by heat sealing. The liner may be utilized in most any type of gas storage system, and is particularly applicable for hydrogen, gas mixtures, and oxygen used for vehicles, fuel cells or regenerative fuel cell applications, high altitude solar powered aircraft, hybrid energy storage/propulsion systems, and lunar/Mars space applications, and other applications requiring high cycle life. 19 figs.

Compact, Lightweight, Ceramic Matrix Composite (CMC) Based Acoustic Liners for Reducing Subsonic Jet Aircraft Engine Noise

NASA Technical Reports Server (NTRS)

Kiser, J. Douglas; Grady, Joseph E.; Miller, Christopher J.; Hultgren, Lennart S.; Jones, Michael G.

2016-01-01

Recent developments have reduced fan and jet noise contributions to overall subsonic aircraft jet-engine noise. Now, aircraft designers are turning their attention toward reducing engine core noise. The NASA Glenn Research Center and NASA Langley Research Center have teamed to investigate the development of a compact, lightweight acoustic liner based on oxide/oxide ceramic matrix composite (CMC) materials. The NASA team has built upon an existing oxide/oxide CMC sandwich structure concept that provides monotonal noise reduction. Oxide/oxide composites have good high temperature strength and oxidation resistance, which could allow them to perform as core liners at temperatures up to 1000C (1832F), and even higher depending on the selection of the composite constituents. NASA has initiated the evaluation of CMC-based liners that use cells of different lengths (variable-depth channels) or effective lengths to achieve broadband noise reduction. Reducing the overall liner thickness is also a major goal, to minimize the volume occupied by the liner. As a first step toward demonstrating the feasibility of our concepts, an oxide/oxide CMC acoustic testing article with different channel lengths was tested. Our approach, summary of test results, current status, and goals for the future are reported.

Investigation of electroforming techniques, literature analysis report

NASA Technical Reports Server (NTRS)

Malone, G. A.

1975-01-01

A literature analysis is presented of reports, specifications, and documented experiences with the use of electroforming to produce copper and nickel structures for aerospace and other engineering applications. The literature period covered is from 1948 to 1974. Specific effort was made to correlate mechanical property data for the electrodeposited material with known electroforming solution compositions and operating conditions. From this survey, electrolytes are suggested for selection to electroform copper and nickel outer shells on regeneratively cooled thrust chamber liners, and other devices subject to thermal and pressure exposure, based on mechanical properties obtainable, performance under various thermal environments, and ease of process control for product reproducibility. Processes of potential value in obtaining sound bonds between electrodeposited copper and nickel and copper alloy substrates are also discussed.

Advanced Manufacturing Technologies (AMT): Additive Manufactured Hot Fire Planning and Testing in GRC Cell 32 Project

NASA Technical Reports Server (NTRS)

Fikes, John C.

2014-01-01

The objective of this project is to hot fire test an additively manufactured thrust chamber assembly TCA (injector and thrust chamber). GRC will install the additively manufactured Inconel 625 injector, two additively manufactured (SLM) water cooled Cu-Cr thrust chamber barrels and one additively manufactured (SLM) water cooled Cu-Cr thrust chamber nozzle on the test stand in Cell 32 and perform hot fire testing of the integrated TCA.

Consideration of liners and covers in performance assessments

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

Phifer, Mark A.; Seitz, Robert R.; Suttora, Linda C.

2014-09-18

On-site disposal cells are in use and being considered at several United States Department of Energy (USDOE) sites as the final disposition for large amounts of waste associated with cleanup of contaminated areas and facilities. These disposal cells are typically regulated by States and/or the U.S. Environmental Protection Agency under the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) in addition to having to comply with requirements in DOE Order 435.1, Radioactive Waste Management due to the radioactive waste. The USDOE-Environmental Management Office of Site Restoration formed a working group to foster improved communication and sharing of information for personnelmore » associated with these CERCLA disposal cells and work towards more consistent assumptions, as appropriate, for technical and policy considerations related to CERCLA risk assessments and DOE Order 435.1 performance assessments in support of a Record of Decision and Disposal Authorization Statement, respectively. One of the issues considered by the working group, which is addressed in this report, was how to appropriately consider the performance of covers and liners/leachate collections systems in the context of a DOE Order 435.1 performance assessment (PA). This same information may be appropriate for consideration within CERCLA risk assessments for these facilities. These OSDCs are generally developed to meet hazardous waste (HW) disposal design standards under the Resource Conservation and Recovery Act (RCRA) as well as the DOE Order 435.1 performance based standards for disposal of radioactive waste. To meet the standards for HW, the facilities typically include engineered covers and liner/leachate collection systems. Thus, when considering such facilities in the context of a DOE Order 435.1 PA, there is a need to address the evolution of performance of covers and liner/leachate collection systems in the context of meeting a performance standard considering time frames of 1,000 years for compliance and potentially thousands of years based on the wastes to test the robustness of the system. Experience has shown that there are a range of expectations and perspectives from the different regulators involved at different sites when reviewing assumptions related to cover and liner/leachate collection system performance. However for HW disposal alone under RCRA the design standards are typically considered sufficient by the regulators without a requirement to assess long-term performance thus avoiding the need to consider the details addressed in this report. This report provides suggestions for a general approach to address covers and liners/leachate collection systems in a DOE Order 435.1 PA and how to integrate assessments with defense-in-depth considerations such as design, operations, and waste acceptance criteria to address uncertainties. The emphasis is on water balances and management in such assessments. Specific information and references are provided for details needed to address the evolution of individual components of cover and liner/leachate collection systems. This information was then synthesized into suggestions for best practices for cover and liner system design and examples of approaches to address the performance of covers and liners as part of a performance assessment of the disposal system. Numerous references are provided for sources of information to help describe the basis for performance of individual components of cover and liner systems.« less

Derivation of the Data Reduction Equations for the Calibration of the Six-component Thrust Stand in the CE-22 Advanced Nozzle Test Facility

NASA Technical Reports Server (NTRS)

Wong, Kin C.

2003-01-01

This paper documents the derivation of the data reduction equations for the calibration of the six-component thrust stand located in the CE-22 Advanced Nozzle Test Facility. The purpose of the calibration is to determine the first-order interactions between the axial, lateral, and vertical load cells (second-order interactions are assumed to be negligible). In an ideal system, the measurements made by the thrust stand along the three coordinate axes should be independent. For example, when a test article applies an axial force on the thrust stand, the axial load cells should measure the full magnitude of the force, while the off-axis load cells (lateral and vertical) should read zero. Likewise, if a lateral force is applied, the lateral load cells should measure the entire force, while the axial and vertical load cells should read zero. However, in real-world systems, there may be interactions between the load cells. Through proper design of the thrust stand, these interactions can be minimized, but are hard to eliminate entirely. Therefore, the purpose of the thrust stand calibration is to account for these interactions, so that necessary corrections can be made during testing. These corrections can be expressed in the form of an interaction matrix, and this paper shows the derivation of the equations used to obtain the coefficients in this matrix.

ERBS fuel addendum: Pollution reduction technology program small jet aircraft engines, phase 3

NASA Technical Reports Server (NTRS)

Bruce, T. W.; Davis, F. G.; Kuhn, T. E.; Mongia, H. C.

1982-01-01

A Model TFE731-2 engine with a low emission, variable geometry combustion system was tested to compare the effects of operating the engine on Commercial Jet-A aviation turbine fuel and experimental referee broad specification (ERBS) fuels. Low power emission levels were essentially identical while the high power NOx emission indexes were approximately 15% lower with the EBRS fuel. The exhaust smoke number was approximately 50% higher with ERBS at the takeoff thrust setting; however, both values were still below the EPA limit of 40 for the Model TFE731 engine. Primary zone liner wall temperature ran an average of 25 K higher with ERBS fuel than with Jet-A. The possible adoption of broadened proprties fuels for gas turbine applications is suggested.

Fabrication of Composite Combustion Chamber/Nozzle for Fastrac Engine

NASA Technical Reports Server (NTRS)

Lawerence, T.; Beshears, R.; Burlingame, S.; Peters, W.; Prince, M.; Suits, M.; Tillery, S.; Burns, L.; Kovach, M.; Roberts, K.;

Fabrication of Composite Combustion Chamber/Nozzle for Fastrac Engine

NASA Technical Reports Server (NTRS)

Lawrence, T.; Beshears, R.; Burlingame, S.; Peters, W.; Prince, M.; Suits, M.; Tillery, S.; Burns, L.; Kovach, M.; Roberts, K.

2001-01-01

The Fastrac Engine developed by the Marshall Space Flight Center for the X-34 vehicle began as a low cost engine development program for a small booster system. One of the key components to reducing the engine cost was the development of an inexpensive combustion chamber/nozzle. Fabrication of a regeneratively cooled thrust chamber and nozzle was considered too expensive and time consuming. In looking for an alternate design concept, the Space Shuttle's Reusable Solid Rocket Motor Project provided an extensive background with ablative composite materials in a combustion environment. An integral combustion chamber/nozzle was designed and fabricated with a silica/phenolic ablative liner and a carbon/epoxy structural overwrap. This paper describes the fabrication process and developmental hurdles overcome for the Fastrac engine one-piece composite combustion chamber/nozzle.

Performance of a small annular turbojet combustor designed for low cost

NASA Technical Reports Server (NTRS)

Fear, J. S.

1972-01-01

Performance investigations were conducted on a combustor utilizing several cost-reducing innovations and designed for use in a low-cost 4448-N thrust turbojet engine for commercial light aircraft. Low-cost features included simple, air-atomizing fuel injectors; combustor liners of perforated sheet; and the use of inexpensive type 304 stainless-steel material. Combustion efficiencies at the cruise and sea-level-takeoff design points were approximately 97 and 98 percent, respectively. The combustor isothermal pressure loss was 6.3 percent at the cruise-condition diffuser inlet Mach number of 0.34. The combustor exit temperature pattern factor was less than 0.24 at both the cruise and sea-level-takeoff design points. The combustor exit average radial temperature profiles at all conditions were in very good agreement with the design profile.

General Electric I-40 Engine at the Lewis Flight Propulsion Laboratory

NASA Image and Video Library

1946-08-21

A mechanic works on a General Electric I-40 turbojet at the National Advisory Committee for Aeronautics (NACA) Lewis Flight Propulsion Laboratory. The military selected General Electric’s West Lynn facility in 1941 to secretly replicate the centrifugal turbojet engine designed by British engineer Frank Whittle. General Electric’s first attempt, the I-A, was fraught with problems. The design was improved somewhat with the subsequent I-16 engine. It was not until the engine's next reincarnation as the I-40 in 1943 that General Electric’s efforts paid off. The 4000-pound thrust I-40 was incorporated into the Lockheed Shooting Star airframe and successfully flown in June 1944. The Shooting Star became the US’s first successful jet aircraft and the first US aircraft to reach 500 miles per hour. The NACA’s Lewis Flight Propulsion Laboratory studied all of General Electric’s centrifugal turbojets both during World War II and afterwards. The entire Shooting Star aircraft was investigated in the Altitude Wind Tunnel during 1945. The researchers studied the engine compressor performance, thrust augmentation using a water injection, and compared different fuel blends in a single combustor. The mechanic in this photograph is inserting a combustion liner into one of the 14 combustor cans. The compressor, which is not yet installed in this photograph, pushed high pressure air into these combustors. There the air mixed with the fuel and was heated. The hot air was then forced through a rotating turbine that powered the engine before being expelled out the nozzle to produce thrust.

NASA Engineer Examines the Design of a Regeneratively-Cooled Rocket Engine

NASA Image and Video Library

1958-12-21

An engineer at the National Aeronautics and Space Administration (NASA) Lewis Research Center examines a drawing showing the assembly and details of a 20,000-pound thrust regeneratively cooled rocket engine. The engine was being designed for testing in Lewis’ new Rocket Engine Test Facility, which began operating in the fall of 1957. The facility was the largest high-energy test facility in the country that was capable of handling liquid hydrogen and other liquid chemical fuels. The facility’s use of subscale engines up to 20,000 pounds of thrust permitted a cost-effective method of testing engines under various conditions. The Rocket Engine Test Facility was critical to the development of the technology that led to the use of hydrogen as a rocket fuel and the development of lightweight, regeneratively-cooled, hydrogen-fueled rocket engines. Regeneratively-cooled engines use the cryogenic liquid hydrogen as both the propellant and the coolant to prevent the engine from burning up. The fuel was fed through rows of narrow tubes that surrounded the combustion chamber and nozzle before being ignited inside the combustion chamber. The tubes are visible in the liner sitting on the desk. At the time, Pratt and Whitney was designing a 20,000-pound thrust liquid-hydrogen rocket engine, the RL-10. Two RL-10s would be used to power the Centaur second-stage rocket in the 1960s. The successful development of the Centaur rocket and the upper stages of the Saturn V were largely credited to the work carried out Lewis.

Life prediction of thermally highly loaded components: modelling the damage process of a rocket combustion chamber hot wall

NASA Astrophysics Data System (ADS)

Schwarz, W.; Schwub, S.; Quering, K.; Wiedmann, D.; Höppel, H. W.; Göken, M.

2011-09-01

During their operational life-time, actively cooled liners of cryogenic combustion chambers are known to exhibit a characteristic so-called doghouse deformation, pursued by formation of axial cracks. The present work aims at developing a model that quantitatively accounts for this failure mechanism. High-temperature material behaviour is characterised in a test programme and it is shown that stress relaxation, strain rate dependence, isotropic and kinematic hardening as well as material ageing have to be taken into account in the model formulation. From fracture surface analyses of a thrust chamber it is concluded that the failure mode of the hot wall ligament at the tip of the doghouse is related to ductile rupture. A material model is proposed that captures all stated effects. Basing on the concept of continuum damage mechanics, the model is further extended to incorporate softening effects due to material degradation. The model is assessed on experimental data and quantitative agreement is established for all tests available. A 3D finite element thermo-mechanical analysis is performed on a representative thrust chamber applying the developed material-damage model. The simulation successfully captures the observed accrued thinning of the hot wall and quantitatively reproduces the doghouse deformation.

Numerical analysis of the hot-gas-side and coolant-side heat transfer in liquid rocket engine combustors

NASA Technical Reports Server (NTRS)

Wang, Ten-See; Van, Luong

1992-01-01

The objective of this paper are to develop a multidisciplinary computational methodology to predict the hot-gas-side and coolant-side heat transfer and to use it in parametric studies to recommend optimized design of the coolant channels for a regeneratively cooled liquid rocket engine combustor. An integrated numerical model which incorporates CFD for the hot-gas thermal environment, and thermal analysis for the liner and coolant channels, was developed. This integrated CFD/thermal model was validated by comparing predicted heat fluxes with those of hot-firing test and industrial design methods for a 40 k calorimeter thrust chamber and the Space Shuttle Main Engine Main Combustion Chamber. Parametric studies were performed for the Advanced Main Combustion Chamber to find a strategy for a proposed combustion chamber coolant channel design.

Acoustic Treatment Design Scaling Methods. Volume 4; Numerical Simulation of the Nonlinear Acoustic Impedance of a Perforated Plate Single-Degree-of-Freedom Resonator Using a Time-Domain Finite Difference Method

NASA Technical Reports Server (NTRS)

Kraft, R. E.

1999-01-01

Single-degree-of-freedom resonators consisting of honeycomb cells covered by perforated facesheets are widely used as acoustic noise suppression liners in aircraft engine ducts. The acoustic resistance and mass reactance of such liners are known to vary with the intensity of the sound incident upon the panel. Since the pressure drop across a perforated liner facesheet increases quadratically with the flow velocity through the facesheet, this is known as the nonlinear resistance effect. In the past, two different empirical frequency domain models have been used to predict the Sound Pressure Level effect of the incident wave on the perforated liner impedance, one that uses the incident particle velocity in isolated narrowbands, and one that models the particle velocity as the overall velocity. In the absence of grazing flow, neither frequency domain model is entirely accurate in predicting the nonlinear effect that is measured for typical perforated sheets. The time domain model is developed in an attempt to understand and improve the model for the effect of spectral shape and amplitude of multi-frequency incident sound pressure on the liner impedance. A computer code for the time-domain finite difference model is developed and predictions using the models are compared to current frequency-domain models.

Concept Assessment of a Fission Fragment Rocket Engine (FFRE) Propelled Spacecraft

NASA Technical Reports Server (NTRS)

Werka, Robert; Clark, Rod; Sheldon, Rob; Percy, Tom

2012-01-01

The March, 2012 issue of Aerospace America stated that ?the near-to-medium prospects for applying advanced propulsion to create a new era of space exploration are not very good. In the current world, we operate to the Moon by climbing aboard a Carnival Cruise Lines vessel (Saturn 5), sail from the harbor (liftoff) shedding whole decks of the ship (staging) along the way and, having reached the return leg of the journey, sink the ship (burnout) and return home in a lifeboat (Apollo capsule). Clearly this is an illogical way to travel, but forced on Explorers by today's propulsion technology. However, the article neglected to consider the one propulsion technology, using today's physical principles that offer continuous, substantial thrust at a theoretical specific impulse of 1,000,000 sec. This engine unequivocally can create a new era of space exploration that changes the way spacecraft operate. Today's space Explorers could travel in Cruise Liner fashion using the technology not considered by Aerospace America, the novel Dusty Plasma Fission Fragment Rocket Engine (FFRE). This NIAC study addresses the FFRE as well as its impact on Exploration Spacecraft design and operation. It uses common physics of the relativistic speed of fission fragments to produce thrust. It radiatively cools the fissioning dusty core and magnetically controls the fragments direction to practically implement previously patented, but unworkable designs. The spacecraft hosting this engine is no more complex nor more massive than the International Space Station (ISS) and would employ the successful ISS technology for assembly and check-out. The elements can be lifted in "chunks" by a Heavy Lift Launcher. This Exploration Spacecraft would require the resupply of small amounts of nuclear fuel for each journey and would be an in-space asset for decades just as any Cruise Liner on Earth. This study has synthesized versions of the FFRE, integrated one concept onto a host spacecraft designed for manned travel to Jupiter's moon, Callisto, and assessed that round trip journey. This engine, although unoptimized, produced 10 pounds force of thrust at a delivered specific impulse of 527,000 seconds for the entire 15-year mission while providing enormous amounts of electrical power to the spacecraft. A payload of 60 metric tons, included in the 300 metric ton vehicle, was carried to Callisto and back; the propellant tanks holding the 4 metric tons of fuel were not jettisoned in the process. The study concluded that the engine and spacecraft are within today's technology, could be built, tested, launched on several SLS (Space Launch System) (or similar) launchers, integrated, checked out, moved to an in-space base such as at a Lagrange point and operated for decades.

GEOSYNTHETIC DESIGN GUIDANCE FOR HAZARDOUS WASTE LANDFILL CELLS AND SURFACE IMPOUNDMENTS

EPA Science Inventory

The report provides guidance design procedures for the use of geosynthetic materials in hazardous waste land disposal cells. Primary geosynthetic components include flexible membrane liners (FML) used to limit the flow of leachate, and leachate collection and removal systems (LCR...

Optimized multisectioned acoustic liners

NASA Technical Reports Server (NTRS)

Baumeister, K. J.

1979-01-01

New calculations show that segmenting is most efficient at high frequencies with relatively long duct lengths where the attenuation is low for both uniform and segmented liners. Statistical considerations indicate little advantage in using optimized liners with more than two segments while the bandwidth of an optimized two-segment liner is shown to be nearly equal to that of a uniform liner. Multielement liner calculations show a large degradation in performance due to changes in assumed input modal structure. Computer programs are used to generate theoretical attenuations for a number of liner configurations for liners in a rectangular duct with no mean flow. Overall, the use of optimized multisectioned liners fails to offer sufficient advantage over a uniform liner to warrant their use except in low frequency single mode application.

Evolution of Gas Cell Targets for Magnetized Liner Inertial Fusion Experiments at the Sandia National Laboratories PECOS Test Facility

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

Paguio, R. R.; Smith, G. E.; Taylor, J. L.

Z-Beamlet (ZBL) experiments conducted at the PECOS test facility at Sandia National Laboratories (SNL) investigated the nonlinear processes in laser plasma interaction (or laserplasma instabilities LPI) that complicate the deposition of laser energy by enhanced absorption, backscatter, filamentation and beam-spray that can occur in large-scale laser-heated gas cell targets. These targets and experiments were designed to provide better insight into the physics of the laser preheat stage of the Magnetized Liner Inertial Fusion (MagLIF) scheme being tested on the SNL Z-machine. The experiments aim to understand the tradeoffs between laser spot size, laser pulse shape, laser entrance hole (LEH) windowmore » thickness, and fuel density for laser preheat. Gas cell target design evolution and fabrication adaptations to accommodate the evolving experiment and scientific requirements are also described in this paper.« less

Evolution of Gas Cell Targets for Magnetized Liner Inertial Fusion Experiments at the Sandia National Laboratories PECOS Test Facility

DOE PAGES

Paguio, R. R.; Smith, G. E.; Taylor, J. L.; ...

2017-12-04

Z-Beamlet (ZBL) experiments conducted at the PECOS test facility at Sandia National Laboratories (SNL) investigated the nonlinear processes in laser plasma interaction (or laserplasma instabilities LPI) that complicate the deposition of laser energy by enhanced absorption, backscatter, filamentation and beam-spray that can occur in large-scale laser-heated gas cell targets. These targets and experiments were designed to provide better insight into the physics of the laser preheat stage of the Magnetized Liner Inertial Fusion (MagLIF) scheme being tested on the SNL Z-machine. The experiments aim to understand the tradeoffs between laser spot size, laser pulse shape, laser entrance hole (LEH) windowmore » thickness, and fuel density for laser preheat. Gas cell target design evolution and fabrication adaptations to accommodate the evolving experiment and scientific requirements are also described in this paper.« less

Cu--Ni--Fe anode for use in aluminum producing electrolytic cell

DOEpatents

Bergsma, S. Craig; Brown, Craig W.; Bradford, Donald R; Barnett, Robert J.; Mezner, Michael B.

2006-07-18

A method of producing aluminum in an electrolytic cell containing alumina dissolved in an electrolyte, the method comprising the steps of providing a molten salt electrolyte at a temperature of less than 900.degree. C. having alumina dissolved therein in an electrolytic cell having a liner for containing the electrolyte, the liner having a bottom and walls extending upwardly from said bottom. A plurality of non-consumable Cu--Ni--Fe anodes and cathodes are disposed in a vertical direction in the electrolyte, the cathodes having a plate configuration and the anodes having a flat configuration to compliment the cathodes. The anodes contain apertures therethrough to permit flow of electrolyte through the apertures to provide alumina-enriched electrolyte between the anodes and the cathodes. Electrical current is passed through the anodes and through the electrolyte to the cathodes, depositing aluminum at the cathodes and producing gas at the anodes.

The effect of cyanide compounds, fluorides, aluminum, and inorganic oxides present in spent pot liner on germination and root tip cells of Lactuca sativa.

PubMed

Andrade, L F; Davide, L C; Gedraite, L S

2010-05-01

SPL (spent pot liner) is a solid waste produced by the aluminum industry. This waste has a highly variable composition, consisting of cyanides, fluorides, organics, and metals. The aim of this work was to study the effect of SPL on root tips of Lactuca sativa using current plant bioassays. We observed a decrease in the germination rate with increasing concentrations of SPL. In addition, SPL was found to reduce root growth, which is correlated with a decrease in the mitotic index. Nevertheless, we noticed a significant enhancement in the percentage of stickiness, c-metaphase, anaphase bridges, and laggard chromosomes in dividing cells and also an increase in the number of cells with condensed nuclei. Moreover, SPL was found to alter the root tip surface, resulting in a reduction in the amount of root hair. These results demonstrate that SPL is a toxic agent that leads to cell damage and disturbance. Copyright 2009 Elsevier Inc. All rights reserved.

Liner Optimization Studies Using the Ducted Fan Noise Prediction Code TBIEM3D

NASA Technical Reports Server (NTRS)

Dunn, M. H.; Farassat, F.

1998-01-01

In this paper we demonstrate the usefulness of the ducted fan noise prediction code TBIEM3D as a liner optimization design tool. Boundary conditions on the interior duct wall allow for hard walls or a locally reacting liner with axially segmented, circumferentially uniform impedance. Two liner optimization studies are considered in which farfield noise attenuation due to the presence of a liner is maximized by adjusting the liner impedance. In the first example, the dependence of optimal liner impedance on frequency and liner length is examined. Results show that both the optimal impedance and attenuation levels are significantly influenced by liner length and frequency. In the second example, TBIEM3D is used to compare radiated sound pressure levels between optimal and non-optimal liner cases at conditions designed to simulate take-off. It is shown that significant noise reduction is achieved for most of the sound field by selecting the optimal or near optimal liner impedance. Our results also indicate that there is relatively large region of the impedance plane over which optimal or near optimal liner behavior is attainable. This is an important conclusion for the designer since there are variations in liner characteristics due to manufacturing imprecisions.

Gas turbine combustor

NASA Technical Reports Server (NTRS)

Burd, Steven W. (Inventor); Cheung, Albert K. (Inventor); Dempsey, Dae K. (Inventor); Hoke, James B. (Inventor); Kramer, Stephen K. (Inventor); Ols, John T. (Inventor); Smith, Reid Dyer Curtis (Inventor); Sowa, William A. (Inventor)

2011-01-01

A gas turbine engine has a combustor module including an annular combustor having a liner assembly that defines an annular combustion chamber having a length, L. The liner assembly includes a radially inner liner, a radially outer liner that circumscribes the inner liner, and a bulkhead, having a height, H1, which extends between the respective forward ends of the inner liner and the outer liner. The combustor has an exit height, H3, at the respective aft ends of the inner liner and the outer liner interior. The annular combustor has a ratio H1/H3 having a value less than or equal to 1.7. The annular combustor may also have a ration L/H3 having a value less than or equal to 6.0.

Fabrication of GRCop-84 Rocket Thrust Chambers

NASA Technical Reports Server (NTRS)

Loewenthal, William; Ellis, David

2006-01-01

GRCop-84, a copper alloy, Cu-8 at% Cr-4 at% Nb developed at NASA Glenn Research Center for regenerative1y cooled rocket engine liners has excellent combinations of elevated temperature strength, creep resistance, thermal conductivity and low cycle fatigue. GRCop-84 is produced from pre-alloyed atomized powder and has been fabricated into plate, sheet and tube forms as well as near net shapes. Fabrication processes to produce demonstration rocket combustion chambers will be presented and includes powder production, extruding, rolling, forming, friction stir welding, and metal spinning. GRCop-84 has excellent workability and can be readily fabricated into complex components using conventional powder and wrought metallurgy processes. Rolling was examined in detail for process sensitivity at various levels of total reduction, rolling speed and rolling temperature representing extremes of commercial processing conditions. Results indicate that process conditions can range over reasonable levels without any negative impact to properties.

Fabrication of GRCop-84 Rocket Thrust Chambers

NASA Technical Reports Server (NTRS)

Loewenthal, William S.; Ellis, David L.

2005-01-01

GRCop-84, a copper alloy, Cu-8 at% Cr-4 at% Nb developed at NASA Glenn Research Center for regeneratively cooled rocket engine liners has excellent combinations of elevated temperature strength, creep resistance, thermal conductivity and low cycle fatigue. GRCop-84 is produced from prealloyed atomized powder and has been fabricated into plate, sheet and tube forms as well as near net shapes. Fabrication processes to produce demonstration rocket combustion chambers will be presented and includes powder production, extruding, rolling, forming, friction stir welding, and metal spinning. GRCop-84 has excellent workability and can be readily fabricated into complex components using conventional powder and wrought metallurgy processes. Rolling was examined in detail for process sensitivity at various levels of total reduction, rolling speed and rolling temperature representing extremes of commercial processing conditions. Results indicate that process conditions can range over reasonable levels without any negative impact to properties.

Development of the Algol III solid rocket motor for SCOUT.

NASA Technical Reports Server (NTRS)

Felix, B. R.; Mcbride, N. M.

1971-01-01

The design and performance of a motor developed for the first stage of the NASA SCOUT-D and E launch vehicles are discussed. The motor delivers a 30% higher total impulse and a 35 to 45% higher payload mass capability than its predecessor, the Algol IIB. The motor is 45 in. in diameter, has a length-to-diameter ratio of 8:1 and delivers an average 100,000-lb thrust for an action time of 72 sec. The motor design features a very high volumetrically loaded internal-burning charge of 17% aluminized polybutadiene propellant, a plasma-welded and heat-treated steel alloy case, and an all-ablative plastic nose liner enclosed in a steel shell. The only significant development problem was the grain design tailoring to account for erosive burning effects which occurred in the high-subsonic-Mach-number port. The tests performed on the motor are described.

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

Cochran, C.B.

This patent describes a double nut setting tool and liner hanger assembly. It comprises a tool which is releasably coupled to the liner hanger by a nut means threadedly connected to the liner hanger: upon reaching a desired setting location, hanging the liner hanger in the well to support the weight of the liner and to permit rotation of the liner: manipulating the string of pipe to simultaneously rotate the nut means to a released condition relative to the liner hanger while rotating a lock nut in a clutch housing into a locking position in the clutch housing to engagemore » the clutch housing with the liner; and applying weight to the string of pipe to engage the clutch housing with the liner when the coupling nut is released and the lock nut is in a locking position so that the liner can be rotated by rotation of the string of pipe after the coupling nut is released.« less

Monolithic Cu-Cr-Nb Alloys for High Temperature, High Heat Flux Applications

NASA Technical Reports Server (NTRS)

Ellis, David L.; Locci, Ivan E.; Michal, Gary M.; Humphrey, Derek M.

1999-01-01

Work during the prior four years of this grant has resulted in significant advances in the development of Cu-8 Cr4 Nb and related Cu-Cr-Nb alloys. The alloys are nearing commercial use in the Reusable Launch Vehicle (RLV) where they are candidate materials for the thrust cell liners of the aerospike engines being developed by Rocketdyne. During the fifth and final year of the grant, it is proposed to complete development of the design level database of mechanical and thermophysical properties and transfer it to NASA Glenn Research Center and Rocketdyne. The database development work will be divided into three main areas: Thermophysical Database Augmentation, Mechanical Testing and Metallography and Fractography. In addition to the database development, work will continue that is focussed on the production of alternatives to the powder metallurgy alloys currently used. Exploration of alternative alloys will be aimed at both the development of lower cost materials and higher performance materials. A key element of this effort will be the use of Thermo-Calc software to survey the solubility behavior of a wide range of alloying elements in a copper matrix. The ultimate goals would be to define suitable alloy compositions and processing routes to produce thin sheets of the material at either a lower cost, or, with improved mechanical and thermal properties compared to the current Cu-Cr-Nb powder metallurgy alloys.

46 CFR Appendix A to Part 535 - Information Form and Instructions

Code of Federal Regulations, 2011 CFR

2011-10-01

... units] (B)Utilization [percent] Carrier A [Name] Liner Service 1 [Name] XX,XXX XX Liner Service 2 XX,XXX XX Liner Service 3 XX,XXX XX Etc. . . . Carrier B Liner Service 1 XX,XXX XX Liner Service 2 XX,XXX XX Liner Service 3 XX,XXX XX Etc. . . . Etc. . . . (C) Narrative statement on significant changes in vessel...

46 CFR Appendix A to Part 535 - Information Form and Instructions

Code of Federal Regulations, 2012 CFR

2012-10-01

... units] (B)Utilization [percent] Carrier A [Name] Liner Service 1 [Name] XX,XXX XX Liner Service 2 XX,XXX XX Liner Service 3 XX,XXX XX Etc. . . . Carrier B Liner Service 1 XX,XXX XX Liner Service 2 XX,XXX XX Liner Service 3 XX,XXX XX Etc. . . . Etc. . . . (C) Narrative statement on significant changes in vessel...

46 CFR Appendix A to Part 535 - Information Form and Instructions

Code of Federal Regulations, 2014 CFR

2014-10-01

... units] (B)Utilization [percent] Carrier A [Name] Liner Service 1 [Name] XX,XXX XX Liner Service 2 XX,XXX XX Liner Service 3 XX,XXX XX Etc. . . . Carrier B Liner Service 1 XX,XXX XX Liner Service 2 XX,XXX XX Liner Service 3 XX,XXX XX Etc. . . . Etc. . . . (C) Narrative statement on significant changes in vessel...

46 CFR Appendix A to Part 535 - Information Form and Instructions

Code of Federal Regulations, 2013 CFR

2013-10-01

... units] (B)Utilization [percent] Carrier A [Name] Liner Service 1 [Name] XX,XXX XX Liner Service 2 XX,XXX XX Liner Service 3 XX,XXX XX Etc. . . . Carrier B Liner Service 1 XX,XXX XX Liner Service 2 XX,XXX XX Liner Service 3 XX,XXX XX Etc. . . . Etc. . . . (C) Narrative statement on significant changes in vessel...

46 CFR Appendix A to Part 535 - Information Form and Instructions

Code of Federal Regulations, 2010 CFR

2010-10-01

... units] (B)Utilization [percent] Carrier A [Name] Liner Service 1 [Name] XX,XXX XX Liner Service 2 XX,XXX XX Liner Service 3 XX,XXX XX Etc. . . . Carrier B Liner Service 1 XX,XXX XX Liner Service 2 XX,XXX XX Liner Service 3 XX,XXX XX Etc. . . . Etc. . . . (C) Narrative statement on significant changes in vessel...

Variable volume combustor with a conical liner support

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

Johnson, Thomas Edward; McConnaughhay, Johnie Franklin; Keener, Chrisophter Paul

The present application provides a variable volume combustor for use with a gas turbine engine. The variable volume combustor may include a liner, a number of micro-mixer fuel nozzles positioned within the liner, and a conical liner support supporting the liner.

Geosynthetic clay liners shrinkage under simulated daily thermal cycles.

PubMed

Sarabadani, Hamid; Rayhani, Mohammad T

2014-06-01

Geosynthetic clay liners are used as part of composite liner systems in municipal solid waste landfills and other applications to restrict the escape of contaminants into the surrounding environment. This is attainable provided that the geosynthetic clay liner panels continuously cover the subsoil. Previous case histories, however, have shown that some geosynthetic clay liner panels are prone to significant shrinkage and separation when an overlying geomembrane is exposed to solar radiation. Experimental models were initiated to evaluate the potential shrinkage of different geosynthetic clay liner products placed over sand and clay subsoils, subjected to simulated daily thermal cycles (60°C for 8 hours and 22°C for 16 hours) modelling field conditions in which the liner is exposed to solar radiation. The variation of geosynthetic clay liner shrinkage was evaluated at specified times by a photogrammetry technique. The manufacturing techniques, the initial moisture content, and the aspect ratio (ratio of length to width) of the geosynthetic clay liner were found to considerably affect the shrinkage of geosynthetic clay liners. The particle size distribution of the subsoil and the associated suction at the geosynthetic clay liner-subsoil interface was also found to have significant effects on the shrinkage of the geosynthetic clay liner. © The Author(s) 2014.

Polyurethane gel liner usage in the Oxford Prosthetic Service.

PubMed

Hatfield, A G; Morrison, J D

2001-04-01

The objective was to investigate which lower limb amputees are using Alpha polyurethane gel liners and the effects of these on comfort and suspension of their prosthesis. A retrospective study was carried out of case records of all patients issued with Alpha cushion and locking liners between 1997 and the end of January 1999. The type of liner used was compared with age, sex, level and cause of amputation, time since amputation, comfort and suspension. Modified Stanmore/Harold-Wood mobility grades; duration of use and number of liners issued per patient were recorded. Sixteen (16) patients were identified who had been prescribed Alpha cushion liners. Improved comfort was reported by all. Forty (40) patients were identified who had been prescribed Alpha locking liners. Twenty (20) of these reported improved comfort and 10 improved suspension. The average time since amputation was 18.5 years for those using cushion liners and 14.1 years for locking liner users. Fifty-two (52) of all 56 patients using Alpha cushion and locking liners had mobility grades of 4 or more. Trauma was the most common cause of amputation. This group is a relatively mobile group of amputees. All those using cushion liners reported improved comfort. Some of the locking liner users reported improved comfort and suspension but this was not universally the case.

Segmented Liner to Control Mode Scattering

NASA Technical Reports Server (NTRS)

Gerhold, Carl H.; Jones, Michael G.; Brown, Martha C.

2013-01-01

The acoustic performance of duct liners can be improved by segmenting the treatment. In a segmented liner treatment, one stage of liner reduces the target sound and scatters energy into other acoustic modes, which are attenuated by a subsequent stage. The Curved Duct Test Rig is an experimental facility in which sound incident on the liner can be generated in a specific mode and the scatter of energy into other modes can be quantified. A series of experiments is performed in which the baseline configuration is asymmetric, that is, a liner is on one side wall of the test duct and the wall opposite is acoustically hard. Segmented liner treatment is achieved by progressively replacing sections of the hard wall opposite with liner in the axial direction, from 25% of the wall surface to 100%. It is found that the energy scatter from the (0,0) to the (0,1) mode reduces as the percentage of opposite wall treatment increases, and the frequency of peak attenuation shifts toward higher frequency. Similar results are found when the incident mode is of order (0,1) and scatter is into the (0,0) mode. The propagation code CDUCT-LaRC is used to predict the effect of liner segmenting on liner performance. The computational results show energy scatter and the effect of liner segmentation that agrees with the experimental results. The experiments and computations both show that segmenting the liner treatment is effective to control the scatter of incident mode energy into other modes. CDUCT-LaRC is shown to be a valuable tool to predict trends of liner performance with liner configuration.

Development of Lead Free Energy Absorber for Space Shuttle Blast Container

NASA Technical Reports Server (NTRS)

Balles, Donald; Ingram, Thomas; Novak, Howard; Schricker, Albert

1998-01-01

The Space Shuttle is connected to the mobile launch platform (MLP) by four aft skirt hold down studs on each solid rocket booster (SRB). Prior to lift-off, the frangible nuts inside the aft skirt blast containers are severed into two nut halves by two pyrotechnic booster cartridges. This action releases the Space Shuttle and allows the hold down studs to eject through the aft skirt bore and then down into the MLP. USBI has been tasked to upgrade the blast container for two specific reasons: (1) To eliminate lead for environmental concerns, and (2) To reduce the chance of nut recontact with the holddown stud. Nut recontact with the stud has been identified as a likely contributor to stud hang-ups. This upgrade will replace the lead liner with a unique open cell aluminum foam material, that has commercial and military uses. The aluminum foam used as an energy absorber is a proven design in many other aerospace/defense applications. Additional benefits of using the open cell, energy absorbent aluminum foam in place of the solid lead liner are: (A) Lead handling/exposure and possible contamination, along with hazardous waste disposal, will be eliminated; (B) Approximately 200 lbs. weight savings will be contributed to each Space Shuttle flight by using aluminum foam instead of lead; (C) The new aluminum liner is designed to catch all shrapnel from frangible nuts, thus virtually eliminating chance of debris exiting the HDP and causing potential damage to the vehicle; and (D) Using the lighter aluminum liner instead of lead, allows for easier assembly and disassembly of blast container elements, which also improves safety, operator handling, and the efficiency of operations.

Development of Lead Free Energy Absorber for Space Shuttle Blast Container

NASA Technical Reports Server (NTRS)

Balles, Donald; Ingram, Thomas; Novak, Howard; Schricker, Albert

1999-01-01

The Space Shuttle is connected to the mobile launch platform (MLP) by four aft skirt hold down studs on each solid rocket booster (SRB). Prior to lift-off, the frangible nuts inside the aft skirt blast containers are severed into two nut halves by two pyrotechnic booster cartridges. This action releases the Space Shuttle and allows the hold down studs to eject through the aft skirt bore and then down into the MLP. USBI has been tasked to upgrade the blast container for two specific reasons: (1) To eliminate lead for environmental concerns, and (2) To reduce the chance of nut recontact with the holddown stud. Nut recontact with the stud has been identified as a likely contributor to stud hang-ups. This upgrade will replace the lead liner with a unique open cell aluminum foam material, that has commercial and military uses. The aluminum foam used as an energy absorber is a proven design in many other aerospace/defense applications. Additional benefits of using the open cell, energy absorbent aluminum foam in place of the solid lead liner are: (1) Lead handling / exposure and possible contamination, along with hazardous waste disposal, will be eliminated; (2) Approximately 200 lbs. weight savings will be contributed to each Space Shuttle flight by using aluminum foam instead of lead; (3) The new aluminum liner is designed to catch all shrapnel from frangible nuts, thus virtually eliminating chance of debris exiting the HDP and causing potential damage to the vehicle; (4) Using the lighter aluminum liner instead of lead, allows for easier assembly and disassembly of blast container elements, which also improves safety, operator handling, and the efficiency of operations.

Progress Report on Rotating Liquid Liner Implosion Experiment, 1 June to 31 December 1975.

DTIC Science & Technology

A critical question in the use of imploding liner flux compression for controlled fusion has been the stability of the inner surface of the liner ...To study the problem experimentally, the existing NRL Imploding Liner Facility was modified to allow the implosion of rotating liquid metal liners ...Rotational stabilization of lthe inner surface of a decelerating liquid sodium-potassium liner has been demonstrated, with excellent circularity of the

Bottom head assembly

DOEpatents

Fife, A.B.

1998-09-01

A bottom head dome assembly is described which includes, in one embodiment, a bottom head dome and a liner configured to be positioned proximate the bottom head dome. The bottom head dome has a plurality of openings extending there through. The liner also has a plurality of openings extending there through, and each liner opening aligns with a respective bottom head dome opening. A seal is formed, such as by welding, between the liner and the bottom head dome to resist entry of water between the liner and the bottom head dome at the edge of the liner. In the one embodiment, a plurality of stub tubes are secured to the liner. Each stub tube has a bore extending there through, and each stub tube bore is coaxially aligned with a respective liner opening. A seat portion is formed by each liner opening for receiving a portion of the respective stub tube. The assembly also includes a plurality of support shims positioned between the bottom head dome and the liner for supporting the liner. In one embodiment, each support shim includes a support stub having a bore there through, and each support stub bore aligns with a respective bottom head dome opening. 2 figs.

Comprehensive review of geosynthetic clay liner and compacted clay liner

NASA Astrophysics Data System (ADS)

Shankar, M. Uma; Muthukumar, M.

2017-11-01

Human activity inevitably produces waste materials that must be managed. Some waste can be reused. However many wastes that cannot be used beneficially must be disposed of ensuring environmental safety. One of the common methods of disposal is landfilling. The most common problems of the landfill site are environmental degradation and groundwater contamination caused by leachate produced during the decomposition process of organic material and rainfall. Liner in a landfill is an important component which prevent leachate migration and prevent groundwater contamination. Earthen liners have been widely used to contain waste materials in landfill. Liners and covers for municipal and hazardous waste containment facilities are often constructed with the use of fine-grained, low plasticity soils. Because of low permeability geosynthetic clay liners and compacted clay liners are the main materials used in waste disposal landfills. This paper summaries the important geotechnical characteristics such as hydraulic conductivity, liquid limit and free swell index of geosynthetic clay liner and compacted clay liner based on research findings. This paper also compares geosynthetic clay liner and compacted clay liner based on certain criteria such as thickness, availability of materials, vulnerability to damage etc.

Open apex shaped charge-type explosive device having special disc means with slide surface thereon to influence movement of open apex shaped charge liner during collapse of same during detonation

DOEpatents

Murphy, Michael J.

1993-01-01

An open apex shape charge explosive device is disclosed having an inner liner defining a truncated cone, an explosive charge surrounding the truncated inner liner, a primer charge, and a disc located between the inner liner and the primer charge for directing the detonation of the primer charge around the end edge of the disc means to the explosive materials surrounding the inner liner. The disc comprises a material having one or more of: a higher compressive strength, a higher hardness, and/or a higher density than the material comprising the inner liner, thereby enabling the disc to resist deformation until the liner collapses. The disc has a slide surface thereon on which the end edge of the inner liner slides inwardly toward the vertical axis of the device during detonation of the main explosive surrounding the inner liner, to thereby facilitate the inward collapse of the inner liner. In a preferred embodiment, the geometry of the slide surface is adjusted to further control the collapse or .beta. angle of the inner liner.

Open apex shaped charge-type explosive device having special disc means with slide surface thereon to influence movement of open apex shaped charge liner during collapse of same during detonation

DOEpatents

Murphy, M.J.

1993-10-12

An open apex shape charge explosive device is disclosed having an inner liner defining a truncated cone, an explosive charge surrounding the truncated inner liner, a primer charge, and a disc located between the inner liner and the primer charge for directing the detonation of the primer charge around the end edge of the disc means to the explosive materials surrounding the inner liner. The disc comprises a material having one or more of: a higher compressive strength, a higher hardness, and/or a higher density than the material comprising the inner liner, thereby enabling the disc to resist deformation until the liner collapses. The disc has a slide surface thereon on which the end edge of the inner liner slides inwardly toward the vertical axis of the device during detonation of the main explosive surrounding the inner liner, to thereby facilitate the inward collapse of the inner liner. In a preferred embodiment, the geometry of the slide surface is adjusted to further control the collapse or [beta] angle of the inner liner. 12 figures.

The vulva skin microclimate: influence of panty liners on temperature, humidity and pH.

PubMed

Runeman, Bo; Rybo, Göran; Larkö, Olle; Faergemann, Jan

2003-01-01

Many women use panty liners between menstrual periods. The aim of this study was to investigate whether the use of such products might influence the vulva skin. Twelve healthy women were studied on four occasions with three different product constructions and on one occasion without products. Temperature, surface wetness and surface pH were measured on vulva skin. Mean skin temperature when the women were wearing a conventional panty liner (with a non-breathable back sheet) was 35.9 degrees C, compared to 34.4 degrees C when wearing no panty liner at all (p < 0.01) and 34.5 degrees C when using a panty liner with a breathable (i.e. vapour permeable) back sheet (p < 0.01). Skin humidity was significantly higher when the conventional panty liner was used compared to no panty liner or to the breathable panty liner (both cases p < 0.01). The mean pH value at the exterior aspect of the labium majus was 5.8 with the conventional panty liner, 5.2 with no panty liner and 5.3 with the breathable panty liner (p < 0.001 and p < 0.01, respectively). The results indicate that the conventional panty liner changes the vulva skin microclimate, but that the breathable panty liner to a substantial degree keeps the microclimate at an undisturbed level. The actual effect of these differences on microbiological flora will be addressed in a subsequent study.

An analysis of cross-coupling of a multicomponent jet engine test stand using finite element modeling techniques

NASA Technical Reports Server (NTRS)

Schweikhard, W. G.; Singnoi, W. N.

1985-01-01

A two axis thrust measuring system was analyzed by using a finite a element computer program to determine the sensitivities of the thrust vectoring nozzle system to misalignment of the load cells and applied loads, and the stiffness of the structural members. Three models were evaluated: (1) the basic measuring element and its internal calibration load cells; (2) the basic measuring element and its external load calibration equipment; and (3) the basic measuring element, external calibration load frame and the altitude facility support structure. Alignment of calibration loads was the greatest source of error for multiaxis thrust measuring systems. Uniform increases or decreases in stiffness of the members, which might be caused by the selection of the materials, have little effect on the accuracy of the measurements. It is found that the POLO-FINITE program is a viable tool for designing and analyzing multiaxis thrust measurement systems. The response of the test stand to step inputs that might be encountered with thrust vectoring tests was determined. The dynamic analysis show a potential problem for measuring the dynamic response characteristics of thrust vectoring systems because of the inherently light damping of the test stand.

Pulsed Electric Propulsion Thrust Stand Calibration Method

NASA Technical Reports Server (NTRS)

Wong, Andrea R.; Polzin, Kurt A.; Pearson, J. Boise

2011-01-01

The evaluation of the performance of any propulsion device requires the accurate measurement of thrust. While chemical rocket thrust is typically measured using a load cell, the low thrust levels associated with electric propulsion (EP) systems necessitate the use of much more sensitive measurement techniques. The design and development of electric propulsion thrust stands that employ a conventional hanging pendulum arm connected to a balance mechanism consisting of a secondary arm and variable linkage have been reported in recent publications by Polzin et al. These works focused on performing steady-state thrust measurements and employed a static analysis of the thrust stand response. In the present work, we present a calibration method and data that will permit pulsed thrust measurements using the Variable Amplitude Hanging Pendulum with Extended Range (VAHPER) thrust stand. Pulsed thrust measurements are challenging in general because the pulsed thrust (impulse bit) occurs over a short timescale (typically 1 micros to 1 millisecond) and cannot be resolved directly. Consequently, the imparted impulse bit must be inferred through observation of the change in thrust stand motion effected by the pulse. Pulsed thrust measurements have typically only consisted of single-shot operation. In the present work, we discuss repetition-rate pulsed thruster operation and describe a method to perform these measurements. The thrust stand response can be modeled as a spring-mass-damper system with a repetitive delta forcing function to represent the impulsive action of the thruster.

Beryllium liner implosion experiments on the Z accelerator in preparation for magnetized liner inertial fusiona)

NASA Astrophysics Data System (ADS)

McBride, R. D.; Martin, M. R.; Lemke, R. W.; Greenly, J. B.; Jennings, C. A.; Rovang, D. C.; Sinars, D. B.; Cuneo, M. E.; Herrmann, M. C.; Slutz, S. A.; Nakhleh, C. W.; Ryutov, D. D.; Davis, J.-P.; Flicker, D. G.; Blue, B. E.; Tomlinson, K.; Schroen, D.; Stamm, R. M.; Smith, G. E.; Moore, J. K.; Rogers, T. J.; Robertson, G. K.; Kamm, R. J.; Smith, I. C.; Savage, M.; Stygar, W. A.; Rochau, G. A.; Jones, M.; Lopez, M. R.; Porter, J. L.; Matzen, M. K.

2013-05-01

Multiple experimental campaigns have been executed to study the implosions of initially solid beryllium (Be) liners (tubes) on the Z pulsed-power accelerator. The implosions were driven by current pulses that rose from 0 to 20 MA in either 100 or 200 ns (200 ns for pulse shaping experiments). These studies were conducted in support of the recently proposed Magnetized Liner Inertial Fusion concept [Slutz et al., Phys. Plasmas 17, 056303 (2010)], as well as for exploring novel equation-of-state measurement techniques. The experiments used thick-walled liners that had an aspect ratio (initial outer radius divided by initial wall thickness) of either 3.2, 4, or 6. From these studies, we present three new primary results. First, we present radiographic images of imploding Be liners, where each liner contained a thin aluminum sleeve for enhancing the contrast and visibility of the liner's inner surface in the images. These images allow us to assess the stability of the liner's inner surface more accurately and more directly than was previously possible. Second, we present radiographic images taken early in the implosion (prior to any motion of the liner's inner surface) of a shockwave propagating radially inward through the liner wall. Radial mass density profiles from these shock compression experiments are contrasted with profiles from experiments where the Z accelerator's pulse shaping capabilities were used to achieve shockless ("quasi-isentropic") liner compression. Third, we present "micro-Ḃ" measurements of azimuthal magnetic field penetration into the initially vacuum-filled interior of a shocked liner. Our measurements and simulations reveal that the penetration commences shortly after the shockwave breaks out from the liner's inner surface. The field then accelerates this low-density "precursor" plasma to the axis of symmetry.

Beryllium liner implosion experiments on the Z accelerator in preparation for magnetized liner inertial fusion

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

McBride, R. D.; Martin, M. R.; Lemke, R. W.

Multiple experimental campaigns have been executed to study the implosions of initially solid beryllium (Be) liners (tubes) on the Z pulsed-power accelerator. The implosions were driven by current pulses that rose from 0 to 20 MA in either 100 or 200 ns (200 ns for pulse shaping experiments). These studies were conducted in support of the recently proposed Magnetized Liner Inertial Fusion concept [Slutz et al., Phys. Plasmas 17, 056303 (2010)], as well as for exploring novel equation-of-state measurement techniques. The experiments used thick-walled liners that had an aspect ratio (initial outer radius divided by initial wall thickness) of eithermore » 3.2, 4, or 6. From these studies, we present three new primary results. First, we present radiographic images of imploding Be liners, where each liner contained a thin aluminum sleeve for enhancing the contrast and visibility of the liner's inner surface in the images. These images allow us to assess the stability of the liner's inner surface more accurately and more directly than was previously possible. Second, we present radiographic images taken early in the implosion (prior to any motion of the liner's inner surface) of a shockwave propagating radially inward through the liner wall. Radial mass density profiles from these shock compression experiments are contrasted with profiles from experiments where the Z accelerator's pulse shaping capabilities were used to achieve shockless (“quasi-isentropic”) liner compression. Third, we present “micro-B-dot ” measurements of azimuthal magnetic field penetration into the initially vacuum-filled interior of a shocked liner. Our measurements and simulations reveal that the penetration commences shortly after the shockwave breaks out from the liner's inner surface. The field then accelerates this low-density “precursor” plasma to the axis of symmetry.« less

A Comparative Study of Four Impedance Eduction Methodologies Using Several Test Liners

NASA Technical Reports Server (NTRS)

Watson, Willie R.; Jones, Michael G.

2013-01-01

A comparative study of four commonly used impedance eduction methods is presented for a range of liner structures and test conditions. Two of the methods are restricted to uniform flow while the other two accommodate both uniform and boundary layer flows. Measurements on five liner structures (a rigid-wall insert, a ceramic tubular liner, a wire mesh liner, a low porosity conventional liner, and a high porosity conventional liner) are obtained using the NASA Langley Grazing Flow Impedance Tube. The educed impedance of each liner is presented for forty-two test conditions (three Mach numbers and fourteen frequencies). In addition, the effects of moving the acoustic source from upstream to downstream and the refractive effects of the mean boundary layer on the wire mesh liner are investigated. The primary conclusions of the study are that: (1) more accurate results are obtained for the upstream source, (2) the uniform flow methods produce nearly identical impedance spectra at and below Mach 0.3 but significant scatter in the educed impedance occurs at the higher Mach number, (3) there is better agreement in educed impedance among the methods for the conventional liners than for the rigid-wall insert, ceramic, or wire mesh liner, and (4) the refractive effects of the mean boundary layer on the educed impedance of the wire mesh liner are generally small except at Mach 0.5.

Processing of Niobium-Lined M240 Machine Gun Barrels

DTIC Science & Technology

2014-11-01

different materials (the gun steel and the niobium liner). A large chunk of the niobium liner in barrel 2 was torn away from the end of the liner at...it to increase the frictional bond between the liner and gun steel . The barrels with liners were hammer forged by FN. FN experienced some...

Advanced Nacelle Acoustic Lining Concepts Development

NASA Technical Reports Server (NTRS)

Bielak, G.; Gallman, J.; Kunze, R.; Murray, P.; Premo, J.; Kosanchick, M.; Hersh, A.; Celano, J.; Walker, B.; Yu, J.;

Optimization and Control of Acoustic Liner Impedance with Bias Flow

NASA Technical Reports Server (NTRS)

Wood, Houston; Follet, Jesse

2000-01-01

Because communities are impacted by steady increases in aircraft traffic, aircraft noise continues to be a growing problem for the growth of commercial aviation. Research has focused on improving the design of specific high noise source areas of aircraft and on noise control measures to alleviate noise radiated from aircraft to the surrounding environment. Engine duct liners have long been a principal means of attenuating engine noise. The ability to control in-situ the acoustic impedance of a liner would provide a valuable tool to improve the performance of liners. The acoustic impedance of a liner is directly related to the sound absorption qualities of that liner. Increased attenuation rates, the ability to change liner acoustic impedance to match various operating conditions, or the ability to tune a liner to more precisely match design impedance represent some ways that in-situ impedance control could be useful. With this in mind, the research to be investigated will focus on improvements in the ability to control liner impedance using a mean flow through the liner which is referred to as bias flow.

LINER FOR EXTRUSION BILLET CONTAINERS. Interim Technical Documentary Progress Report, June 5, 1962-September 5, 1962

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

Spachner, S.A.

1962-10-31

A container-sleeve-liner assembly was designed which will provide adequate support for ceramic, ceramic coated metal, or metal liners. The design minimizes mechanical property requirements of liner materials, and permits rapid removal of worn or damaged liners. A high-strength stem was designed and fabricated. Technical literature on high-strength materials was reviewed, and high-strength materials producers were contacted to locate sources and assess applicability of existing materials for refractory metal extrusion liner use. (auth)

An Investigation of Secondary Jetting Phenomena ’Hyperjet’ Shaped Charge.

DTIC Science & Technology

1982-08-01

Hyperjet design. Primarily flash x ray techniques would be used to measure jet velocities resulting from secon- dary collisions. A formal report would be...the liner in time: a- X 2 (t-t1 ) 2 Ph __ Eqns. 2 Where a = Liner acceleration of some point in the liner Pcj = Chapman-Jouget explosive pressure Ps...liner. Since liner accerleration of any point along the liner is known, it is therefore possible to describe the governing equation of motion as: d2R = a

Evaluation of Novel Liner Concepts for Fan and Airframe Noise Reduction

NASA Technical Reports Server (NTRS)

Jones, M. G.; Howerton, B. M.

2016-01-01

This paper presents a review of four novel liner concepts: soft vanes, over-the-rotor liners, external liners, and flap side-edge liners. A number of similarities in the design and evaluation of these concepts emerged during these investigations. Since these were the first attempts to study these particular liner concepts, there was limited information to guide the design process. In all cases, the target frequencies (or frequency range) were known, but the optimum acoustic impedance and optimum liner placement were typically not known. For these cases, the maximum available surface was used and a c-impedance was targeted based on the assumption the sound field impinges on the surface at normal incidence. This choice proved fruitful for every application. An impedance prediction model was used to design variable-depth liner configurations, and a graphical design code (ILIAD) was developed to aid in this process. The ability to build increasingly complex liner configurations via additive manufacturing was key, such that multiple designs could quickly be tested in a normal incidence impedance tube. The Two-Thickness Method was used to evaluate available bulk materials, such that bulk liners could also be considered for each application. These novel liner concepts provide sufficient noise reduction to warrant further investigations.

Development of 1D Liner Compression Code for IDL

NASA Astrophysics Data System (ADS)

Shimazu, Akihisa; Slough, John; Pancotti, Anthony

2015-11-01

A 1D liner compression code is developed to model liner implosion dynamics in the Inductively Driven Liner Experiment (IDL) where FRC plasmoid is compressed via inductively-driven metal liners. The driver circuit, magnetic field, joule heating, and liner dynamics calculations are performed at each time step in sequence to couple these effects in the code. To obtain more realistic magnetic field results for a given drive coil geometry, 2D and 3D effects are incorporated into the 1D field calculation through use of correction factor table lookup approach. Commercial low-frequency electromagnetic fields solver, ANSYS Maxwell 3D, is used to solve the magnetic field profile for static liner condition at various liner radius in order to derive correction factors for the 1D field calculation in the code. The liner dynamics results from the code is verified to be in good agreement with the results from commercial explicit dynamics solver, ANSYS Explicit Dynamics, and previous liner experiment. The developed code is used to optimize the capacitor bank and driver coil design for better energy transfer and coupling. FRC gain calculations are also performed using the liner compression data from the code for the conceptual design of the reactor sized system for fusion energy gains.

Design, Development and Hotfire Testing of Monolithic Copper and Bimetallic Additively Manufactured Combustion Chambers

NASA Technical Reports Server (NTRS)

Gradl, Paul; Barnett, Greg; Brandsmeier, Will; Greene, Sandy Elam; Protz, Chris

2016-01-01

NASA and industry partners are working towards fabrication process development to reduce costs and schedules associated with manufacturing liquid rocket engine components with the goal of reducing overall mission costs. One such technique being evaluated is powder-bed fusion or selective laser melting (SLM) otherwise commonly referred to as additive manufacturing. The NASA Low Cost Upper Stage Propulsion (LCUSP) program was designed to develop processes and material characterization for the GRCop-84 copper-alloy commensurate with powder bed additive manufacturing, evaluate bimetallic deposition and complete testing of a full scale combustion chamber. As part of this development, the process has been transferred to industry partners to enable a long-term supply chain of monolithic copper combustion chambers. As a direct spin off of this program, NASA is working with industry partners to further develop the printing process for the GRCop-84 material in addition to the C-18150 (CuCrZr) material. To advance the process further and allow for optimization with multiple materials, NASA is also investigating the feasibility of bimetallic additively manufactured chambers. A 1.2k sized thrust-chamber was designed and developed to compare the printing process of the GRCop-84 and C-18150 SLM materials. A series of similar MCC liners also completed development with an Inconel 625 jacket bonded to the GRcop-84 liner evaluating direct metal deposition (DMD) laser and arc-based techniques. This paper describes the design, development, manufacturing and testing of these combustion chambers and associated lessons learned throughout the design and development process.

Investigation of the effect of a power feed vacuum gap in solid liner experiments at 1 MA

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

Bott-Suzuki, S. C., E-mail: sbottsuzuki@ucsd.edu, E-mail: sbottsuzuki@p3ucsd.com; Cordaro, S. W.; Caballero Bendixsen, L. S.

We present an experimental study of plasma initiation of a solid metal liner at the 1 MA level. In contrast to previous work, we introduce a vacuum gap at one of the liner connections to the power feed to investigate how this affects plasma initiation and to infer how this may affect the symmetry of the liner in compression experiments. We observed that the vacuum gap causes non-uniform plasma initiation both azimuthally and axially in liners, diagnosed by gated optical imaging. Using magnetic field probes external to the liner, we also determined that the optical emission is strongly linked to themore » current distribution in the liner. The apparent persistent of azimuthal non-uniformities may have implications for fusion-scale liner experiments.« less

Physics Criteria for a Subscale Plasma Liner Experiment

DOE PAGES

Hsu, Scott C.; Thio, Yong C. Francis

2018-02-02

Spherically imploding plasma liners, formed by merging hypersonic plasma jets, are a proposed standoff driver to compress magnetized target plasmas to fusion conditions (Hsu et al. in IEEE Trans Plasma Sci 40:1287, 2012). Here, in this paper, the parameter space and physics criteria are identified for a subscale, plasma-liner-formation experiment to provide data, e.g., on liner ram-pressure scaling and uniformity, that are relevant for addressing scientific issues of full-scale plasma liners required to achieve fusion conditions. Lastly, based on these criteria, we quantitatively estimate the minimum liner kinetic energy and mass needed, which informed the design of a subscale plasmamore » liner experiment now under development.« less

Physics Criteria for a Subscale Plasma Liner Experiment

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

Hsu, Scott C.; Thio, Yong C. Francis

Spherically imploding plasma liners, formed by merging hypersonic plasma jets, are a proposed standoff driver to compress magnetized target plasmas to fusion conditions (Hsu et al. in IEEE Trans Plasma Sci 40:1287, 2012). Here, in this paper, the parameter space and physics criteria are identified for a subscale, plasma-liner-formation experiment to provide data, e.g., on liner ram-pressure scaling and uniformity, that are relevant for addressing scientific issues of full-scale plasma liners required to achieve fusion conditions. Lastly, based on these criteria, we quantitatively estimate the minimum liner kinetic energy and mass needed, which informed the design of a subscale plasmamore » liner experiment now under development.« less

Segmented ceramic liner for induction furnaces

DOEpatents

Gorin, Andrew H.; Holcombe, Cressie E.

1994-01-01

A non-fibrous ceramic liner for induction furnaces is provided by vertically stackable ring-shaped liner segments made of ceramic material in a light-weight cellular form. The liner segments can each be fabricated as a single unit or from a plurality of arcuate segments joined together by an interlocking mechanism. Also, the liner segments can be formed of a single ceramic material or can be constructed of multiple concentric layers with the layers being of different ceramic materials and/or cellular forms. Thermomechanically damaged liner segments are selectively replaceable in the furnace.

Segmented ceramic liner for induction furnaces

DOEpatents

Gorin, A.H.; Holcombe, C.E.

1994-07-26

A non-fibrous ceramic liner for induction furnaces is provided by vertically stackable ring-shaped liner segments made of ceramic material in a light-weight cellular form. The liner segments can each be fabricated as a single unit or from a plurality of arcuate segments joined together by an interlocking mechanism. Also, the liner segments can be formed of a single ceramic material or can be constructed of multiple concentric layers with the layers being of different ceramic materials and/or cellular forms. Thermomechanically damaged liner segments are selectively replaceable in the furnace. 5 figs.

Thrust stand evaluation of engine performance improvement algorithms in an F-15 airplane

NASA Technical Reports Server (NTRS)

Conners, Timothy R.

1992-01-01

An investigation is underway to determine the benefits of a new propulsion system optimization algorithm in an F-15 airplane. The performance seeking control (PSC) algorithm optimizes the quasi-steady-state performance of an F100 derivative turbofan engine for several modes of operation. The PSC algorithm uses an onboard software engine model that calculates thrust, stall margin, and other unmeasured variables for use in the optimization. As part of the PSC test program, the F-15 aircraft was operated on a horizontal thrust stand. Thrust was measured with highly accurate load cells. The measured thrust was compared to onboard model estimates and to results from posttest performance programs. Thrust changes using the various PSC modes were recorded. Those results were compared to benefits using the less complex highly integrated digital electronic control (HIDEC) algorithm. The PSC maximum thrust mode increased intermediate power thrust by 10 percent. The PSC engine model did very well at estimating measured thrust and closely followed the transients during optimization. Quantitative results from the evaluation of the algorithms and performance calculation models are included with emphasis on measured thrust results. The report presents a description of the PSC system and a discussion of factors affecting the accuracy of the thrust stand load measurements.

Evaluation of tensile bond strength of heat cure and autopolymerizing silicone-based resilient denture liners before and after thermocycling.

PubMed

Madan, Nishtha; Datta, Kusum

2012-01-01

To assess the effect of simulated mouth conditions reproduced with thermocycling on the tensile bond strength of two silicone based resilient denture liners with acrylic resin bases. Two silicone-based soft denture liners (Mollosil - Chairside autopolymerization and Molloplast B - Heat polymerization) were tested. For each liner, 30 specimens with a cross-sectional area of 10 Χ 10 mm and thickness 3 mm were processed between two acrylic blocks (Trevalon). Specimens were divided into a control group that was stored for 24 hours in water at 37°C and a test group that was thermocycled (2500 cycles) between baths of 5° and 55°C. Tensile bond strength (kg/cm²) was determined in a universal testing machine using crosshead speed of 5 mm/min. The student t-test was used to determine the significance of the difference in bond strength between the two liners. The mean tensile bond strength for control and thermocycled specimens of the two liners were: Mollosil (6.82 kg/cm² and 8.41 kg/cm²) and Molloplast-B (16.30 kg/cm² and 13.67 kg/cm²), respectively. Comparison of bond strength of control specimens with thermocycled specimens of the liners indicated a significant difference for both Mollosil (P=0.045) and Molloplast-B (P=0.027). Comparison between control specimens of both liners and thermocycled specimens of both liners indicated a highly significant difference (P<0.001). Heat polymerized resilient denture liner Molloplast-B had higher tensile bond strength than autopolymerizing liner Mollosil regardless of thermocycling. The bond strength of Mollosil increased after thermocycling while that of Molloplast-B decreased after thermocycling. Although heat-polymerized denture liners require more processing time than autopolymerizing liners, but they display much better adhesion properties to denture base resin and should thus be preferred when soft liner has to be used for a longer duration of time.

Magnetized Target Fusion Driven by Plasma Liners

NASA Technical Reports Server (NTRS)

Thio, Y. C. Francis; Eskridge, Richard; Smith, James; Lee, Michael; Richeson, Jeff; Schmidt, George; Knapp, Charles E.; Kirkpatrick, Ronald C.; Turchi, Peter J.; Rodgers, Stephen L. (Technical Monitor)

2001-01-01

Magnetized target fusion (MTF) attempts to combine the favorable attributes of magnetic confinement fusion (MCF) for energy confinement with the attributes of inertial confinement fusion (ICF) for efficient compression heating and wall-free containment of the fusing plasma. It uses a material liner to compress and contain a magnetized plasma. For practical applications, standoff drivers to deliver the imploding momentum flux to the target plasma remotely are required. Spherically converging plasma jets have been proposed as standoff drivers for this purpose. The concept involves the dynamic formation of a spherical plasma liner by the merging of plasma jets, and the use of the liner so formed to compress a spheromak or a field reversed configuration (FRC). For the successful implementation of the scheme, plasma jets of the requisite momentum flux density need to be produced. Their transport over sufficiently large distances (a few meters) needs to be assured. When they collide and merge into a liner, relative differences in velocity, density and temperature of the jets could give rise to instabilities in the development of the liner. Variation in the jet properties must be controlled to ensure that the growth rate of the instabilities are not significant over the time scale of the liner formation before engaging with the target plasma. On impact with the target plasma, some plasma interpenetration might occur between the liner and the target. The operating parameter space needs to be identified to ensure that a reasonably robust and conducting contact surface is formed between the liner and the target. A mismatch in the "impedance" between the liner and the target plasma could give rise to undesirable shock heating of the liner leading to increased entropy (thermal losses) in the liner. Any irregularities in the liner will accentuate the Rayleigh-Taylor instabilities during the compression of the target plasma by the liner.

Configuration Effects on Liner Performance

NASA Technical Reports Server (NTRS)

Gerhold, Carl H.; Brown, Martha C.; Jones, Michael G.; Howerton, Brian M.

2012-01-01

The acoustic performance of a duct liner depends not only on the intrinsic properties of the liner but also on the configuration of the duct in which it is used. A series of experiments is performed in the NASA Langley Research Center Curved Duct Test Rig (at Mach 0.275) to evaluate the effect of duct configuration on the acoustic performance of single degree of freedom perforate-over-honeycomb liners. The liners form the sidewalls of the duct's test section. Variations of duct configuration include: asymmetric (liner on one side and hard wall opposite) and symmetric (liner on both sides) wall treatment; inlet and exhaust orientation, in which the sound propagates either against or with the flow; and straight and curved flow path. The effect that duct configuration has on the overall acoustic performance, particularly the shift in frequency and magnitude of peak attenuation, is quantified. The redistribution of incident mode content is shown. The liners constitute the side walls of the liner test section and the scatter of incident horizontal order 1 mode by the asymmetric treatment and order 2 mode by the symmetric treatment into order 0 mode is shown. Scatter of order 0 incident modes into higher order modes is also shown. This redistribution of mode content is significant because it indicates that the liner design can be manipulated such that energy is scattered into more highly attenuated modes, thus enhancing liner performance.

Evaluation of Skin Friction Drag for Liner Applications in Aircraft

NASA Technical Reports Server (NTRS)

Gerhold, Carl H.; Brown, Martha C.; Jasinski, Christopher M.

2016-01-01

A parameter that is gaining significance in the evaluation of acoustic liner performance is the skin friction drag induced by air flow over the liner surface. Estimates vary widely regarding the amount of drag the liner induces relative to a smooth wall, from less than a 20% increase to nearly 100%, and parameters such as face sheet perforate hole diameter, percent open area, and sheet thickness are expected to figure prominently in the skin friction drag. Even a small increase in liner drag can impose an economic penalty, and current research is focused on developing 'low drag' liner concepts, with the goal being to approach the skin friction drag of a smooth wall. The issue of skin friction drag takes on greater significance as airframe designers investigate the feasibility of putting sound absorbing liners on the non-lifting surfaces of the wings and fuselage, for the purpose of reducing engine noise reflected and scattered toward observers on the ground. Researchers at the NASA Langley Research Center have embarked on investigations of liner skin friction drag with the aims of: developing a systematic drag measurement capability, establishing the drag of current liners, and developing liners that produce reduced drag without compromising acoustic performance. This paper discusses the experimental procedures that have been developed to calculate the drag coefficient based on the change in momentum thickness and the companion research program being carried out to measure the drag directly using a force balance. Liner samples that are evaluated include a solid wall with known roughness and conventional liners with perforated facesheets of varying hole diameter and percent open area.

Design and preliminary results of a semitranspiration cooled (Lamilloy) liner for a high-pressure high-temperature combustor

NASA Technical Reports Server (NTRS)

Wear, J. D.; Trout, A. M.; Smith, J. M.; Jones, R. E.

1978-01-01

A Lamilloy combustor liner was designed, fabricated and tested in a combustor at pressures up to 8 atmospheres. The liner was fabricated of a three layer Lamilloy structure and designed to replace a conventional step louver liner. The liner is to be used in a combustor that provides hot gases to a turbine cooling test facility at pressures up to 40 atmospheres. The Lamilloy liner was tested extensively at lower pressures and demonstrated lower metal temperatures than the conventional liner, while at the same time requiring about 40 percent less cooling air flow. Tests conducted at combustor exit temperatures in excess of 2200 K have not indicated any cooling or durability problems with the Lamilloy linear.

Flow Duct Data for Validation of Acoustic Liner Codes for Impedance Eduction

NASA Technical Reports Server (NTRS)

Ahuja, K. K.; Munro, Scott; Gaeta, R. J., Jr.

2000-01-01

The objective of the study reported here was to acquire acoustic and flow data with hard and lined duct wall duct sections for validation of a liner prediction code being developed at NASA LaRC. Both the mean flowfield and acoustic flowfields were determined in a cross-plane of the rectangular duct. A flow duct facility with acoustic drivers connected to a rectangular (4.7 x 2.0 inch) source section and a linear acoustic liner mounted downstream of the source section was used in this study. The liner section was designed to allow liner materials to be placed on all 4 walls of the duct. The test liner was of the locally-reacting type and was made from a ceramic material. The material, consisting of a tubular structure, was provided by NASA LaRC. The liner was approximately 8.89 cm (3.5 inches) thick. For the current study, only the two "short" sides of the duct were lined with liner material. The other two sides were hard walls. Two especially built instrumentation sections were attached on either sides of the liner section to allow acoustic and flow measurements to be made upstream and downstream of the liner. The two instrumentation duct sections were built to allow measurement of acoustic and flow properties at planes perpendicular to flow upstream and downstream of the liner section. The instrumentation section was also designed to provide a streamwise gradient in acoustic (complex) pressure from which the acoustic particle velocity, needed for the model validation, can be computed. Flow measurements included pressure, temperature, and velocity profiles upstream of the liner section. The in-flow sound pressure levels and phases were obtained with a microphone probe equipped with a nose cone in two cross planes upstream of the liner and two cross plane downstream of the liner. In addition to the acoustic measurements at the cross planes. axial centerline acoustic data was acquired using an axially traversing microphone probe which was traversed from a location upstream of the liner to some distance downstream of the liner. All probes used here had to be calibrated with respect to a standard microphone equipped with a nose cone to allow for the effects of flow.

Long-term behavior of water content and density in an earthen liner

USGS Publications Warehouse

Frank, T.E.; Krapac, I.G.; Stark, T.D.; Strack, G.D.

2005-01-01

An extensively instrumented compacted earthen liner was constructed at the Illinois State Geological Survey facility in Champaign, III. in 1987. A pond of water 0.31 m deep was maintained on top of the 7.3 m ?? 14.6 m ?? 0.9 m thick liner for 14 years. One of the goals of the project was to evaluate the long-term performance of a compacted earthen liner by monitoring the long-term changes in water content and density. The water content of the earthen liner showed no trend with depth or time. The liner density remained essentially constant from construction through excavation in 2002. The liner did not become fully saturated. Upon excavation of the liner, the degree of saturation was 80.0??6.3% after 14 years of ponding under a hydraulic head of 0.31 m. The results imply that properly designed and constructed earthen liners may reduce the possibility of pollutants leaching from municipal solid waste containment facilities by remaining partially saturated for years and maintaining the placement density. Journal of Geotechnical and Geoenvironmental Engineering ?? ASCE.

Evaluation of a Variable-Impedance Ceramic Matrix Composite Acoustic Liner

NASA Technical Reports Server (NTRS)

Jones, M. G.; Watson, W. R.; Nark, D. M.; Howerton, B. M.

2014-01-01

As a result of significant progress in the reduction of fan and jet noise, there is growing concern regarding core noise. One method for achieving core noise reduction is via the use of acoustic liners. However, these liners must be constructed with materials suitable for high temperature environments and should be designed for optimum absorption of the broadband core noise spectrum. This paper presents results of tests conducted in the NASA Langley Liner Technology Facility to evaluate a variable-impedance ceramic matrix composite acoustic liner that offers the potential to achieve each of these goals. One concern is the porosity of the ceramic matrix composite material, and whether this might affect the predictability of liners constructed with this material. Comparisons between two variable-depth liners, one constructed with ceramic matrix composite material and the other constructed via stereolithography, are used to demonstrate this material porosity is not a concern. Also, some interesting observations are noted regarding the orientation of variable-depth liners. Finally, two propagation codes are validated via comparisons of predicted and measured acoustic pressure profiles for a variable-depth liner.

The Aerodynamic Performance of an Over-the-Rotor Liner With Circumferential Grooves on a High Bypass Ratio Turbofan Rotor

NASA Technical Reports Server (NTRS)

Bozak, Richard F.; Hughes, Christopher E.; Buckley, James

2013-01-01

While liners have been utilized throughout turbofan ducts to attenuate fan noise, additional attenuation is obtainable by placing an acoustic liner over-the-rotor. Previous experiments have shown significant fan performance losses when acoustic liners are installed over-the-rotor. The fan blades induce an oscillating flow in the acoustic liners which results in a performance loss near the blade tip. An over-the-rotor liner was designed with circumferential grooves between the fan blade tips and the acoustic liner to reduce the oscillating flow in the acoustic liner. An experiment was conducted in the W-8 Single-Stage Axial Compressor Facility at NASA Glenn Research Center on a 1.5 pressure ratio fan to evaluate the impact of this over-the-rotor treatment design on fan aerodynamic performance. The addition of a circumferentially grooved over-the-rotor design between the fan blades and the acoustic liner reduced the performance loss, in terms of fan adiabatic efficiency, to less than 1 percent which is within the repeatability of this experiment.

The Aerodynamic Performance of an Over-The-Rotor Liner with Circumferential Grooves on a High Bypass Ratio Turbofan Rotor

NASA Technical Reports Server (NTRS)

Bozak, Rick; Hughes, Christopher; Buckley, James

2013-01-01

While liners have been utilized throughout turbofan ducts to attenuate fan noise, additional attenuation is obtainable by placing an acoustic liner over-the-rotor. Previous experiments have shown significant fan performance losses when acoustic liners are installed over-the-rotor. The fan blades induce an oscillating flow in the acoustic liners which results in a performance loss near the blade tip. An over-the-rotor liner was designed with circumferential grooves between the fan blade tips and the acoustic liner to reduce the oscillating flow in the acoustic liner. An experiment was conducted in the W-8 Single-Stage Axial Compressor Facility at NASA Glenn Research Center on a 1.5 pressure ratio fan to evaluate the impact of this over-the-rotor treatment design on fan aerodynamic performance. The addition of a circumferentially grooved over-the-rotor design between the fan blades and the acoustic liner reduced the performance loss, in terms of fan adiabatic efficiency, to less than 1% which is within the repeatability of this experiment.

Fretting and Corrosion Between a Metal Shell and Metal Liner May Explain the High Rate of Failure of R3 Modular Metal-on-Metal Hips.

PubMed

Ilo, Kevin C; Derby, Emma J; Whittaker, Robert K; Blunn, Gordon W; Skinner, John A; Hart, Alister J

2017-05-01

The R3 acetabular system used with its metal liner has higher revision rates when compared to its ceramic and polyethylene liner. In June 2012, the medical and healthcare products regulatory agency issued an alert regarding the metal liner of the R3 acetabular system. Six retrieved R3 acetabular systems with metal liners underwent detailed visual analysis using macroscopic and microscopic techniques. Visual analysis discovered corrosion on the backside of the metal liners. There was a distinct border to the areas of corrosion that conformed to antirotation tab insertions on the inner surface of the acetabular shell, which are for the polyethylene liner. Scanning electron microscopy indicated evidence of crevice corrosion, and energy-dispersive X-ray analysis confirmed corrosion debris rich in titanium. The high failure rate of the metal liner option of the R3 acetabular system may be attributed to corrosion on the backside of the liner which appear to result from geometry and design characteristics of the acetabular shell. Copyright © 2016 Elsevier Inc. All rights reserved.

Measurement of the current and symmetry of the impact liner on the NTLX experiments

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

Stokes, J. L.; Tabaka, L. J.; Parker, J. V.

A series of four liner implosion experiments, denoted the Near Tern Liner Experiments (NTLX) was recently conducted on the Shiva Star capacitor bank at the Air Force Research Laboratory (AFRL). Measurement of the driving currents in these experiments is required for postshot analysis of the liner implosion and experiments conducted in the target cylinder. A Faraday rotation measurement was fielded on Shiva Star to measure the current and compare with the current measured by a Rogowski coil technique. The Faraday rotation technique measured the 16 MA currents in these experiments with better than 1% precision. In addition, six B-dot probesmore » were fielded at equal angles around a circle in the powerflow channel outside the liner to measure the symmetry of the liner impact on the target cylinder. The B-dot probes measure the local Idot, which has a jump when the liner impacts the target cylinder. A high-pass filter allows one to measure this jump more accurately. From the relative timing of the jump signals, the offset of the liner axis and the circularity of liner are inferred.« less

CCARES: A computer algorithm for the reliability analysis of laminated CMC components

NASA Technical Reports Server (NTRS)

Duffy, Stephen F.; Gyekenyesi, John P.

1993-01-01

Structural components produced from laminated CMC (ceramic matrix composite) materials are being considered for a broad range of aerospace applications that include various structural components for the national aerospace plane, the space shuttle main engine, and advanced gas turbines. Specifically, these applications include segmented engine liners, small missile engine turbine rotors, and exhaust nozzles. Use of these materials allows for improvements in fuel efficiency due to increased engine temperatures and pressures, which in turn generate more power and thrust. Furthermore, this class of materials offers significant potential for raising the thrust-to-weight ratio of gas turbine engines by tailoring directions of high specific reliability. The emerging composite systems, particularly those with silicon nitride or silicon carbide matrix, can compete with metals in many demanding applications. Laminated CMC prototypes have already demonstrated functional capabilities at temperatures approaching 1400 C, which is well beyond the operational limits of most metallic materials. Laminated CMC material systems have several mechanical characteristics which must be carefully considered in the design process. Test bed software programs are needed that incorporate stochastic design concepts that are user friendly, computationally efficient, and have flexible architectures that readily incorporate changes in design philosophy. The CCARES (Composite Ceramics Analysis and Reliability Evaluation of Structures) program is representative of an effort to fill this need. CCARES is a public domain computer algorithm, coupled to a general purpose finite element program, which predicts the fast fracture reliability of a structural component under multiaxial loading conditions.

EVALUATION OF LANDFILL-LINER DESIGNS

EPA Science Inventory

The effectiveness of landfill-liner designs is evaluated in terms of the slope, drainage length, and saturated hydraulic conductivity of the lateral drainage layer, the saturated hydraulic conductivity of the soil liner, and the fraction of the area under a synthetic liner where ...

Small gas turbine combustor experimental study - Compliant metal/ceramic liner and performance evaluation

NASA Technical Reports Server (NTRS)

Acosta, W. A.; Norgren, C. T.

1986-01-01

Combustor research relating to the development of fuel efficient small gas turbine engines capable of meeting future commercial and military aviation needs is currently underway at NASA Lewis. As part of this combustor research, a basic reverse-flow combustor has been used to investigate advanced liner wall cooling techniques. Liner temperature, performance, and exhaust emissions of the experimental combustor utilizing compliant metal/ceramic liners were determined and compared with three previously reported combustors that featured: (1)splash film-cooled liner walls; (2) transpiration cooled liner walls; and (3) counter-flow film cooled panels.

Small gas turbine combustor experimental study: Compliant metal/ceramic liner and performance evaluation

NASA Technical Reports Server (NTRS)

Acosta, W. A.; Norgren, C. T.

1986-01-01

Combustor research relating to the development of fuel efficient small gas turbine engines capable of meeting future commercial and military aviation needs is currently underway at NASA Lewis. As part of this combustor research, a basic reverse-flow combustor has been used to investigate advanced liner wall cooling techniques. Liner temperature, performance, and exhaust emissions of the experimental combustor utilizing compliant metal/ceramic liners were determined and compared with three previously reported combustors that featured: (1) splash film-cooled liner walls; (2) transpiration cooled liner walls; and (3) counter-flow film cooled panels.

RQL Sector Rig Testing of SiC/SiC Combustor Liners

NASA Technical Reports Server (NTRS)

Verrilli, Michael J.; Martin, Lisa C.; Brewer, David N.

2002-01-01

Combustor liners, manufactured from silicon carbide fiber-reinforced silicon carbide (SiC/SiC) were tested for 260 hr using a simulated gas turbine engine cycle. This report documents the results of the last 56 hr of testing. Damage occurred in one of the six different components that make up the combustor liner set, the rich zone liner. Cracks in the rich zone liner initiated at the leading edge due to stresses resulting from the component attachment configuration. Thin film thermocouples and fiber optic pyrometers were used to measure the rich zone liner's temperature and these results are reported.

Filament wound metal lined propellant tanks for future Earth-to-orbit transports

NASA Technical Reports Server (NTRS)

Macconochie, Ian O.; Davis, Robert B.; Freeman, William T., Jr.

1988-01-01

For future Earth-to-orbit transport vehicles, reusability and lighter weights are sought for the main propellant tanks. To achieve this, a filament wound tank with a metal liner and an intermediate layer of foam-filled honeycomb is proposed. A hydrogen tank is used as an example. To accommodate mismatches in the expansion of liner and overwrap a design is proposed wherin the liner is configured so that the extension of the liner under pressure matches the expected contraction of the same liner due to the presence of a cryogen. In operation, the liner is pressurized at a rate such that the pressure strain matches the contraction due to decrease in temperature. As an alternate approach, compressive pre-stress is placed in the liner such that it will not separate from the overwrap. A finite element program is used to show stresses in the liner and overwrap for various tank pressures for the pre-stressed liner concept. A fracture mechanics analysis is made of the liners to determine tank life. The tank concept shown has a similar weight to the Shuttle external hydrogen tank, but the filament wound tank is expected to be reusable. Integration of the propellant tanks into a future transport vehicle is discussed.

Broadband Liner Optimization for the Source Diagnostic Test Fan

NASA Technical Reports Server (NTRS)

Nark, Douglas M.; Jones, Michael G.

2012-01-01

The broadband component of fan noise has grown in relevance with the utilization of increased bypass ratio and advanced fan designs. Thus, while the attenuation of fan tones remains paramount, the ability to simultaneously reduce broadband fan noise levels has become more appealing. This paper describes a broadband acoustic liner optimization study for the scale model Source Diagnostic Test fan. Specifically, in-duct attenuation predictions with a statistical fan source model are used to obtain optimum impedance spectra over a number of flow conditions for three liner locations in the bypass duct. The predicted optimum impedance information is then used with acoustic liner modeling tools to design liners aimed at producing impedance spectra that most closely match the predicted optimum values. Design selection is based on an acceptance criterion that provides the ability to apply increased weighting to specific frequencies and/or operating conditions. Typical tonal liner designs targeting single frequencies at one operating condition are first produced to provide baseline performance information. These are followed by multiple broadband design approaches culminating in a broadband liner targeting the full range of frequencies and operating conditions. The broadband liner is found to satisfy the optimum impedance objectives much better than the tonal liner designs. In addition, the broadband liner is found to provide better attenuation than the tonal designs over the full range of frequencies and operating conditions considered. Thus, the current study successfully establishes a process for the initial design and evaluation of novel broadband liner concepts for complex engine configurations.

User experience of transtibial prosthetic liners: A systematic review.

PubMed

Richardson, Amy; Dillon, Michael P

2017-02-01

The liner is an integral part of a transtibial prosthesis designed to protect the residual limb, enhance comfort and provide suspension. Literature is difficult to interpret and use given the variety of interventions, outcome measures and method designs. Critical appraisal and synthesis of the evidence is needed to help inform decisions about liner prescription based on the user experience. To critically appraise and synthesise research describing the user experience of transtibial prosthetic liners. Systematic review. A comprehensive suite of databases were searched using terms related to amputation level, liner type and user experience. Included studies were in English and measured the first-person experience of using a transtibial liner. Studies were appraised using the McMaster University Critical Review Forms. A total of 18 articles met the inclusion criteria. While the quality of the evidence has improved over time, a number of common issues (e.g. sampling bias, validity of outcome measures, incorrect inferential analysis) reduce our ability to differentiate between the user experience of different transtibial liners. There is insufficient research to differentiate between the user experience of different transtibial liners. High-quality research is needed to inform decisions about liner prescription based on the user experience. Clinical relevance The available evidence suggests that the user experience of commonly reported problems (e.g. sweating) may be very similar between different liners. Aspects of the user experience that differ most between liners (e.g. unwanted noises, rotation within the socket) can help focus attention on what matters most when discussing prescription.

Impedance Eduction in Sound Fields With Peripherally Varying Liners and Flow

NASA Technical Reports Server (NTRS)

Watson, W. R.; Jones, M. G.

2015-01-01

A two-dimensional impedance eduction theory is extended to three-dimensional sound fields and peripherally varying duct liners. The approach is to first measure the acoustic pressure field at a series of flush-mounted wall microphones located around the periphery of the flow duct. The numerical solution for the acoustic pressure field at these microphones is also obtained by solving the three-dimensional convected Helmholtz equation using the finite element method. A quadratic objective function based on the difference between the measured and finite element solution is constructed and the unknown impedance function is obtained by minimizing this objective function. Impedance spectra educed for two uniform-structure liners (a wire-mesh and a conventional liner) and a hard-soft-hard peripherally varying liner (for which the soft segment is that of the conventional liner) are presented. Results are presented at three mean flow Mach numbers and fourteen sound source frequencies. The impedance spectra of the uniform-structure liners are also computed using a two-dimensional impedance eduction theory. The primary conclusions of the study are: 1) when measured data is used with the uniform-structure liners, the three-dimensional theory reproduces the same impedance spectra as the two-dimensional theory except for frequencies corresponding to very low or very high liner attenuation; and 2) good agreement between the educed impedance spectra of the uniform structure conventional liner and the soft segment of the peripherally varying liner is obtained.

ELECTRICAL LEAK LOCATION METHOD FOR GEOMEMBRANE LINERS

EPA Science Inventory

Geomembrane liners are sheets of polymeric materials used to prevent leakage of waste from and infiltration of rainwater into solid waste landfills and surface impoundments. The method described consists of voltage applied between the liner and the earth under the liner which pro...

Foam-Metal Liner Attenuation of Low-Speed Fan Noise

NASA Technical Reports Server (NTRS)

Sutliff, Daniel L.; Jones, Michael G.

2008-01-01

A foam-metal liner for attenuation of fan noise was developed for and tested on a low speed fan. This type of liner represents a significant advance over traditional liners due to the possibility for placement in close proximity to the rotor. An advantage of placing treatment in this region is the modification of the acoustic near field, thereby inhibiting noise generation mechanisms. This can result in higher attenuation levels than can be achieved by liners located in the nacelle inlet. In addition, foam-metal liners could potentially replace the fan rub-strip and containment components, ultimately reducing engine components and thus weight, which can result in a systematic increase in noise reduction and engine performance. Foam-metal liners have the potential to reduce fan noise by 4 dB based on this study.

Water movement through an experimental soil liner

USGS Publications Warehouse

Krapac, I.G.; Cartwright, K.; Panno, S.V.; Hensel, B.R.; Rehfeldt, K.R.; Herzog, B.L.

1991-01-01

A field-scale soil liner was constructed to test whether compacted soil barriers in cover and liner systems could be built to meet the U.S. EPA saturated hydraulic conductivity requirement (???1 x 10-7 cm s-1). The 8 x 15 x 0.9m liner was constructed in 15 cm compacted lifts using a 20,037 kg pad-foot compactor and standard engineering practices. Water infiltration into the liner has been monitored for one year. Monitoring will continue until water break through at the base of the liner occurs. Estimated saturated hydraulic conductivities were 2.5 x 10-9, 4.0 x 10-8, and 5.0 x 10-8 cm s-1 based on measurements of water infiltration into the liner by large- and small-ring infiltrometers and a water balance analysis, respectively. Also investigated in this research was the variability of the liner's hydraulic properties and estimates of the transit times for water and tracers. Small variances exhibited by small-ring flux data suggested that the liner was homogeneous with respect to infiltration fluxes. The predictions of water and tracer breakthrough at the base of the liner ranged from 2.4-12.6 y, depending on the method of calculation and assumptions made. The liner appeared to be saturated to a depth between 18 and 33 cm at the end of the first year of monitoring. Transit time calculations cannot be verified yet, since breakthrough has not occurred. The work conducted so far indicates that compacted soil barriers can be constructed to meet the saturated hydraulic conductivity requirement established by the U.S. EPA.A field-scale soil liner was constructed to test whether compacted soil barriers in cover and liner systems could be built to meet the U.S. EPA saturated hydraulic conductivity requirement (??? 1 ?? 10-7 cm s-1). The 8 ?? 15 ?? 0.9 m liner was constructed in 15 cm compacted lifts using a 20.037 kg pad-foot compactor and standard engineering practices. Water infiltration into the liner has been monitored for one year. Monitoring will continue until water break through at the base of the liner occurs. Estimated saturated hydraulic conductivities were 2.5 ?? 10-9, 4.0 ?? 10-8, and 5.0 ?? 10-8 cm s-1 based on measurements of water infiltration into the liner by large- and small-ring infiltrometers and a water balance analysis, respectively. Also investigated in this research was the variability of the liner's hydraulic properties and estimates of the transit times for water and tracers. Small variances exhibited by small-ring flux data suggested that the liner was homogeneous with respect to infiltration fluxes. The predictions of water and tracer breakthrough at the base of the liner ranged from 2.4-12.6 y, depending on the method of calculation and assumptions made. The liner appeared to be saturated to a depth between 18 and 33 cm at the end of the first year of monitoring. Transit time calculations cannot be verified yet, since breakthrough has not occurred. The work conducted so far indicates that compacted soil barriers can be constructed to meet the saturated hydraulic conductivity requirement established by the U.S. EPA.

The influence of head diameter and wall thickness on deformations of metallic acetabular press-fit cups and UHMWPE liners: a finite element analysis.

PubMed

Goebel, Paul; Kluess, Daniel; Wieding, Jan; Souffrant, Robert; Heyer, Horst; Sander, Manuela; Bader, Rainer

2013-03-01

To increase the range of motion of total hip endoprostheses, prosthetic heads need to be enlarged, which implies that the cup and/or liner thickness must decrease. This may have negative effects on the wear rate, because the acetabular cups and liners could deform during press-fit implantation and hip joint loading. We compared the metal cup and polyethylene liner deformations that occurred when different wall thicknesses were used in order to evaluate the resulting changes in the clearance of the articulating region. A parametric finite element model utilized three cup and liner wall thicknesses to analyze cup and liner deformations after press-fit implantation into the pelvic bone. The resultant hip joint force during heel strike was applied while the femur was fixed, accounting for physiological muscle forces. The deformation behavior of the liner under joint loading was therefore assessed as a function of the head diameter and the resulting clearance. Press-fit implantation showed diametral cup deformations of 0.096, 0.034, and 0.014 mm for cup wall thicknesses of 3, 5, and 7 mm, respectively. The largest deformations (average 0.084 ± 0.003 mm) of liners with thicknesses of 4, 6, and 8 mm occurred with the smallest cup wall thickness (3 mm). The smallest liner deformation (0.011 mm) was obtained with largest cup and liner wall thicknesses. Under joint loading, liner deformations in thin-walled acetabular cups (3 mm) reduced the initial clearance by about 50 %. Acetabular press-fit cups with wall thicknesses of ≤5 mm should only be used in combination with polyethylene liners >6 mm thick in order to minimize the reduction in clearance.

FOAM-IN-PLACE FORM FITTING HELMET LINERS

DTIC Science & Technology

A urethane foam formulation has been developed to produce foamed-in-place helmet liners for Air Force crash or flying helmets. High density urethane...foam helmet liners has been foamed-in-place directly on the flying crew member’s head, producing a perfectly fitting helmet liner with a minimum of...time, labor and inconvenience. These liners were produced at an extremely modest cost. Design and fabrication of a suitable mold in which the helmet

Investigation of Liner Characteristics in the NASA Langley Curved Duct Test Rig

NASA Technical Reports Server (NTRS)

Gerhold, Carl H.; Brown, Martha C.; Watson, Willie R.; Jones, Michael G.

2007-01-01

The Curved Duct Test Rig (CDTR), which is designed to investigate propagation of sound in a duct with flow, has been developed at NASA Langley Research Center. The duct incorporates an adaptive control system to generate a tone in the duct at a specific frequency with a target Sound Pressure Level and a target mode shape. The size of the duct, the ability to isolate higher order modes, and the ability to modify the duct configuration make this rig unique among experimental duct acoustics facilities. An experiment is described in which the facility performance is evaluated by measuring the sound attenuation by a sample duct liner. The liner sample comprises one wall of the liner test section. Sound in tones from 500 to 2400 Hz, with modes that are parallel to the liner surface of order 0 to 5, and that are normal to the liner surface of order 0 to 2, can be generated incident on the liner test section. Tests are performed in which sound is generated without axial flow in the duct and with flow at a Mach number of 0.275. The attenuation of the liner is determined by comparing the sound power in a hard wall section downstream of the liner test section to the sound power in a hard wall section upstream of the liner test section. These experimentally determined attenuations are compared to numerically determined attenuations calculated by means of a finite element analysis code. The code incorporates liner impedance values educed from measured data from the NASA Langley Grazing Incidence Tube, a test rig that is used for investigating liner performance with flow and with (0,0) mode incident grazing. The analytical and experimental results compare favorably, indicating the validity of the finite element method and demonstrating that finite element prediction tools can be used together with experiment to characterize the liner attenuation.

Effects of broadened property fuels on radiant heat flux to gas turbine combustor liners

NASA Technical Reports Server (NTRS)

Haggard, J. B., Jr.

1983-01-01

The effects of fuel type, inlet air pressure, inlet air temperature, and fuel/air ratio on the combustor radiation were investigated. Combustor liner radiant heat flux measurements were made in the spectral region between 0.14 and 6.5 microns at three locations in a modified commercial aviation can combustor. Two fuels, Jet A and a heavier distillate research fuel called ERBS were used. The use of ERBS fuel as opposed to Jet A under similar operating conditions resulted in increased radiation to the combustor liner and hence increased backside liner temperature. This increased radiation resulted in liner temperature increases always less than 73 C. The increased radiation is shown by way of calculations to be the result of increased soot concentrations in the combustor. The increased liner temperatures indicated can substantially affect engine maintenance costs by reducing combustor liner life up to 1/3 because of the rapid decay in liner material properties when operated beyond their design conditions.

The vulvar skin microenvironment: influence of different panty liners on temperature, pH and microflora.

PubMed

Runeman, Bo; Rybo, Göran; Forsgren-Brusk, Ulla; Larkö, Olle; Larsson, Peter; Faergemann, Jan

2004-01-01

The aim of this study was to confirm findings that vapour-impermeable panty liners might impair skin climate, and to assess their impact on the skin microflora. Temperature, surface pH and aerobic microflora were measured on vulvar skin of 102 women. The mean skin temperature was 1.1 degrees C higher when using a vapour-impermeable panty liner compared with not using one. Use of panty liners with vapour-permeable back sheets and acidic cores resulted in skin temperature, pH and microflora levels that were very close to those observed in persons not using liners. The temperature, pH and total number of microorganisms were significantly lower for users of vapour-permeable panty liners than for users of vapour-impermeable ones (p <0.05, p<0.001 and p<0.001, respectively). The microorganism densities were usually higher when using the vapour-impermeable panty liner, but mean differences were minor. The use of panty liners seems not to imply a microbial risk for normal, healthy women.

Evaluation of Geopolymer Concrete for Rocket Test Facility Flame Deflectors

NASA Technical Reports Server (NTRS)

Allgood, Daniel C.; Montes, Carlos; Islam, Rashedul; Allouche, Erez

2014-01-01

The current paper presents results from a combined research effort by Louisiana Tech University (LTU) and NASA Stennis Space Center (SSC) to develop a new alumina-silicate based cementitious binder capable of acting as a high performance refractory material with low heat ablation rate and high early mechanical strength. Such a binder would represent a significant contribution to NASA's efforts to develop a new generation of refractory 'hot face' liners for liquid or solid rocket plume environments. This project was developed as a continuation of on-going collaborations between LTU and SSC, where test sections of a formulation of high temperature geopolymer binder were cast in the floor and walls of Test Stand E-1 Cell 3, an active rocket engine test stand flame trench. Additionally, geopolymer concrete panels were tested using the NASA-SSC Diagnostic Test Facility (DTF) thruster, where supersonic plume environments were generated on a 1ft wide x 2ft long x 6 inch deep refractory panel. The DTF operates on LOX/GH2 propellants producing a nominal thrust of 1,200 lbf and the combustion chamber conditions are Pc=625psig, O/F=6.0. Data collected included high speed video of plume/panel area and surface profiles (depth) of the test panels measured on a 1-inch by 1-inch giving localized erosion rates during the test. Louisiana Tech conducted a microstructure analysis of the geopolymer binder after the testing program to identify phase changes in the material.

High-temperature combustor liner tests in structural component response test facility

NASA Technical Reports Server (NTRS)

Moorhead, Paul E.

1988-01-01

Jet engine combustor liners were tested in the structural component response facility at NASA Lewis. In this facility combustor liners were thermally cycled to simulate a flight envelope of takeoff, cruise, and return to idle. Temperatures were measured with both thermocouples and an infrared thermal imaging system. A conventional stacked-ring louvered combustor liner developed a crack at 1603 cycles. This test was discontinued after 1728 cycles because of distortion of the liner. A segmented or float wall combustor liner tested at the same heat flux showed no significant change after 1600 cycles. Changes are being made in the facility to allow higher temperatures.

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

Randolph, B.

Composite liners have been fabricated for the Los Alamos liner driven HEDP experiments using impactors formed by physical vapor deposition (PVD), electroplating, machining and shrink fitting. Chemical vapor deposition (CVD) has been proposed for some ATLAS liner applications. This paper describes the processes used to fabricate machined and shrink fitted impactors which have been used for copper impactors in 1100 aluminum liners and 6061 T-6 aluminum impactors in 1100 aluminum liners. The most successful processes have been largely empirically developed and rely upon a combination of shrink fitted and light press fitting. The processes used to date will be describedmore » along with some considerations for future composite liners requirements in the HEDP Program.« less

Effect of ceramic coating of JT8D combustor liner on maximum liner temperatures and other combustor performance parameters

NASA Technical Reports Server (NTRS)

Butze, H. F.; Liebert, C. H.

1976-01-01

The effect of ceramic coating of a JT8D combustor liner was investigated at simulated cruise and takeoff conditions with two fuels of widely different aromatic contents. Substantial decreases in maximum liner temperatures and flame radiation values were obtained with the ceramic-coated liner. Small reductions in exhaust gas smoke concentrations were observed with the ceramic-coated liner. Other performance parameters such as combustion efficiency and emissions of unburned hydrocarbons, CO, and NOx were not affected significantly. No deterioration of the ceramic coating was observed after about 6 hours of cyclic operation including several startups and shutdowns.

Effects of Liner Length and Attenuation on NASA Langley Impedance Eduction

NASA Technical Reports Server (NTRS)

Jones, M. G.; Watson, W. R.

2016-01-01

This study explores the effects of liner length and attenuation on the CHE (convected Helmholtz equation) impedance eduction method, in which the surface impedance of an acoustic liner is inferred through an iterative process based on repeated solutions to the convected Helmholtz equation. Wire mesh-over-honeycomb and perforate-over-honeycomb acoustic liners are tested in the NASA Langley Grazing Flow Impedance Tube, and the resultant data are processed using two impedance eduction methods. The first is the CHE method, and the second is a direct method (labeled the KT method) that uses the Kumaresan and Tufts algorithm to compute the impedance directly. The CHE method has been extensively used for acoustic liner evaluation, but experiences anomalous behavior under some test conditions. It is postulated that the anomalies are related to the liner length and/or attenuation. Since the KT method only employs data measured over the length of the liner, it is expected to be unaffected by liner length. A comparison of results achieved with the two impedance eduction methods is used to explore the interactive effects of liner length and attenuation on the CHE impedance eduction method.

Optimization of Variable-Depth Liner Configurations for Increased Broadband Noise Reduction

NASA Technical Reports Server (NTRS)

Jones, M. G.; Watson, W. R.; Nark, D. M.; Schiller, N. H.; Born, J. C.

2016-01-01

This paper employs three acoustic propagation codes to explore variable-depth liner configurations for the NASA Langley Grazing Flow Impedance Tube (GFIT). The initial study demonstrates that a variable impedance can acceptably be treated as a uniform impedance if the spatial extent over which this variable impedance occurs is less than one-third of a wavelength of the incident sound. A constrained optimization study is used to design a variable-depth liner and to select an optimization metric. It also provides insight regarding how much attenuation can be achieved with variable-depth liners. Another optimization study is used to design a liner with much finer chamber depth resolution for the Mach 0.0 and 0.3 test conditions. Two liners are designed based on spatial rearrangement of chambers from this liner to determine whether the order is critical. Propagation code predictions suggest this is not the case. Both liners are fabricated via additive manufacturing and tested in the GFIT for the Mach 0.0 condition. Predicted and measured attenuations compare favorably across the full frequency range. These results clearly suggest that the chambers can be arranged in any order, thus offering the potential for innovative liner designs to minimize depth and weight.

Hybrid Active/Passive Jet Engine Noise Suppression System

NASA Technical Reports Server (NTRS)

Parente, C. A.; Arcas, N.; Walker, B. E.; Hersh, A. S.; Rice, E. J.

1999-01-01

A novel adaptive segmented liner concept has been developed that employs active control elements to modify the in-duct sound field to enhance the tone-suppressing performance of passive liner elements. This could potentially allow engine designs that inherently produce more tone noise but less broadband noise, or could allow passive liner designs to more optimally address high frequency broadband noise. A proof-of-concept validation program was undertaken, consisting of the development of an adaptive segmented liner that would maximize attenuation of two radial modes in a circular or annular duct. The liner consisted of a leading active segment with dual annuli of axially spaced active Helmholtz resonators, followed by an optimized passive liner and then an array of sensing microphones. Three successively complex versions of the adaptive liner were constructed and their performances tested relative to the performance of optimized uniform passive and segmented passive liners. The salient results of the tests were: The adaptive segmented liner performed well in a high flow speed model fan inlet environment, was successfully scaled to a high sound frequency and successfully attenuated three radial modes using sensor and active resonator arrays that were designed for a two mode, lower frequency environment.

Shock wave absorber having a deformable liner

DOEpatents

Youngdahl, C.K.; Wiedermann, A.H.; Shin, Y.W.; Kot, C.A.; Ockert, C.E.

1983-08-26

This invention discloses a shock wave absorber for a piping system carrying liquid. The absorber has a plastically deformable liner defining the normal flow boundary for an axial segment of the piping system, and a nondeformable housing is spaced outwardly from the liner so as to define a gas-tight space therebetween. The flow capacity of the liner generally corresponds to the flow capacity of the piping system line, but the liner has a noncircular cross section and extends axially of the piping system line a distance between one and twenty times the diameter thereof. Gas pressurizes the gas-tight space equal to the normal liquid pressure in the piping system. The liner has sufficient structural capacity to withstand between one and one-half and two times this normal liquid pressures; but at greater pressures it begins to plastically deform initially with respect to shape to a more circular cross section, and then with respect to material extension by circumferentially stretching the wall of the liner. A high energy shock wave passing through the liner thus plastically deforms the liner radially into the gas space and progressively also as needed in the axial direction of the shock wave to minimize transmission of the shock wave beyond the absorber.

MEASUREMENT OF THE CURRENT AND SYMMETRY OF THE IMPACT LINER ON THE NTLX EXPERIMENTS

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

J. STOKES; J. PARKER; ET AL

A series of four liner implosion experiments, denoted the Near Term Liner Experiments (NTLX) was recently conducted on the Shiva Star capacitor bank at the Air Force Research Laboratory (AFRL). Measurement of the driving currents in these experiments is required for post-shot analysis of the liner implosion and experiments conducted in the target cylinder. A Faraday rotation measurement was fielded on Shiva Star to measure the current and compare with the current measured by a Rogowski coil technique. The Faraday rotation technique measured the 16 MA currents in these experiments with better than 1% precision. In addition, six B-dot probesmore » were fielded at equal angles around a circle in the powerflow channel outside the liner to measure the symmetry of the liner impact on the target cylinder. The B-dot probes measure the local I-dot, which has a jump when the liner impacts the target cylinder. A high-pass filter allows one to measure this jump more accurately. From the relative timing of the jump signals, the offset of the liner axis and the circularity of liner are inferred.« less

Do Changes in the Production Process Affect the Outcome of Ceramic Liners: A 3-Year Follow-Up Study.

PubMed

Schmidt-Braekling, Tom; Renner, Lisa; Mintz, Douglas N; Waldstein, Wenzel; Endo, Yoshimi; Boettner, Friedrich

2017-04-01

In 2011, the current liner was withdrawn from the market because of the potential risk for liner fracture secondary to increased pressures used to assemble the metal locking ring. The present study provides a short-term follow-up of patients with this implant. We retrospectively evaluated 63 consecutive hips in 53 patients operated by a single surgeon using a recalled ceramic-on-ceramic bearing. There were 30 women and 23 men with an average age of 50.6 years (range 20.3-63.5 years). The mean follow-up was 36.8 months. Six hips in 6 patients were revised (9.5%) because of a liner-fracture during the follow-up period. All liner fractures were identified on computer tomography imaging. Nine patients had self-reported episodes of squeaking (14.3%). All 6 patients that underwent revision surgery for liner fracture described squeaking before revision. There were no revisions for other causes. Two of the revised patients had a subsequent dislocation (33%). The recalled ceramic liner lots have an increased liner fracture rate. Patients with mechanical symptoms or squeaking should undergo computer tomography to rule out liner facture. Copyright © 2016 Elsevier Inc. All rights reserved.

Advanced liner-cooling techniques for gas turbine combustors

NASA Technical Reports Server (NTRS)

Norgren, C. T.; Riddlebaugh, S. M.

1985-01-01

Component research for advanced small gas turbine engines is currently underway at the NASA Lewis Research Center. As part of this program, a basic reverse-flow combustor geometry was being maintained while different advanced liner wall cooling techniques were investigated. Performance and liner cooling effectiveness of the experimental combustor configuration featuring counter-flow film-cooled panels is presented and compared with two previously reported combustors featuring: splash film-cooled liner walls; and transpiration cooled liner walls (Lamilloy).

A Method for Optimizing Non-Axisymmetric Liners for Multimodal Sound Sources

NASA Technical Reports Server (NTRS)

Watson, W. R.; Jones, M. G.; Parrott, T. L.; Sobieski, J.

2002-01-01

Central processor unit times and memory requirements for a commonly used solver are compared to that of a state-of-the-art, parallel, sparse solver. The sparse solver is then used in conjunction with three constrained optimization methodologies to assess the relative merits of non-axisymmetric versus axisymmetric liner concepts for improving liner acoustic suppression. This assessment is performed with a multimodal noise source (with equal mode amplitudes and phases) in a finite-length rectangular duct without flow. The sparse solver is found to reduce memory requirements by a factor of five and central processing time by a factor of eleven when compared with the commonly used solver. Results show that the optimum impedance of the uniform liner is dominated by the least attenuated mode, whose attenuation is maximized by the Cremer optimum impedance. An optimized, four-segmented liner with impedance segments in a checkerboard arrangement is found to be inferior to an optimized spanwise segmented liner. This optimized spanwise segmented liner is shown to attenuate substantially more sound than the optimized uniform liner and tends to be more effective at the higher frequencies. The most important result of this study is the discovery that when optimized, a spanwise segmented liner with two segments gives attenuations equal to or substantially greater than an optimized axially segmented liner with the same number of segments.

Posttest destructive examination of the steel liner in a 1:6-scale reactor containment model

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

Lambert, L.D.

A 1:6-scale model of a nuclear reactor containment model was built and tested at Sandia National Laboratories as part of research program sponsored by the Nuclear Regulatory Commission to investigate containment overpressure test was terminated due to leakage from a large tear in the steel liner. A limited destructive examination of the liner and anchorage system was conducted to gain information about the failure mechanism and is described. Sections of liner were removed in areas where liner distress was evident or where large strains were indicated by instrumentation during the test. The condition of the liner, anchorage system, and concretemore » for each of the regions that were investigated are described. The probable cause of the observed posttest condition of the liner is discussed.« less

Magnetized Target Fusion Driven by Plasma Liners

NASA Technical Reports Server (NTRS)

Thio, Y. C. Francis; Cassibry, Jason; Eskridge, Richard; Kirkpatrick, Ronald C.; Knapp, Charles E.; Lee, Michael; Martin, Adam; Smith, James; Wu, S. T.; Rodgers, Stephen L. (Technical Monitor)

2001-01-01

For practical applications of magnetized target fusion, standoff drivers to deliver the imploding momentum flux to the target plasma remotely are required. Quasi-spherically converging plasma jets have been proposed as standoff drivers for this purpose. The concept involves the dynamic formation of a quasi-spherical plasma liner by the merging of plasma jets, and the use of the liner so formed to compress a spheromak or a field reversed configuration (FRC). Theoretical analysis and computer modeling of the concept are presented. It is shown that, with the appropriate choice of the flow parameters in the liner and the target, the impact between the liner and the target plasma can be made to be shockless in the liner or to generate at most a very weak shock in the liner. Additional information is contained in the original extended abstract.

Low-Speed Fan Noise Attenuation from a Foam-Metal Liner

NASA Technical Reports Server (NTRS)

Sutliff, Daniel L.; Jones, Michael G.

2011-01-01

A foam-metal liner for attenuation of fan noise was developed for and tested on a low-speed fan. This type of liner represents a significant advance over traditional liners, due to the possibility of placement in close proximity to the rotor. An advantage of placing treatment in this region is that the acoustic near field is modified, thereby inhibiting the noise-generation mechanism. This can result in higher attenuation levels than could be achieved by liners located in the nacelle inlet. In addition, foam-metal liners could potentially replace the fan rub strip and containment components, ultimately reducing engine components and thus weight, which can result in a systematic increase in noise reduction and engine performance. Foam-metal liners have the potential to reduce fan noise by 4 dB based on this study.

75 FR 1596 - Grant of Authority for Subzone Status, Reynolds Packaging LLC (Aluminum Foil Liner Stock...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-01-12

... Status, Reynolds Packaging LLC (Aluminum Foil Liner Stock), Louisville, Kentucky Pursuant to its...-purpose subzone at the aluminum foil liner stock manufacturing and distribution facilities of Reynolds... manufacturing and distribution of aluminum foil liner stock and aluminum foil at the facilities of Reynolds...

TBIEM3D: A Computer Program for Predicting Ducted Fan Engine Noise. Version 1.1

NASA Technical Reports Server (NTRS)

Dunn, M. H.

1997-01-01

This document describes the usage of the ducted fan noise prediction program TBIEM3D (Thin duct - Boundary Integral Equation Method - 3 Dimensional). A scattering approach is adopted in which the acoustic pressure field is split into known incident and unknown scattered parts. The scattering of fan-generated noise by a finite length circular cylinder in a uniform flow field is considered. The fan noise is modeled by a collection of spinning point thrust dipoles. The program, based on a Boundary Integral Equation Method (BIEM), calculates circumferential modal coefficients of the acoustic pressure at user-specified field locations. The duct interior can be of the hard wall type or lined. The duct liner is axisymmetric, locally reactive, and can be uniform or axially segmented. TBIEM3D is written in the FORTRAN programming language. Input to TBIEM3D is minimal and consists of geometric and kinematic parameters. Discretization and numerical parameters are determined automatically by the code. Several examples are presented to demonstrate TBIEM3D capabilities.

Experimental and theoretical investigation of fatigue life in reusable rocket thrust chambers

NASA Technical Reports Server (NTRS)

Hannum, N. P.; Kasper, H. J.; Pavli, A. J.

1976-01-01

During a test program to investigate low-cycle thermal fatigue, 13 rocket combustion chambers were fabricated and cyclically test fired to failure. Six oxygen-free, high-conductivity (OFHC) copper and seven Amzirc chambers were tested. The chamber liners were fabricated of copper or copper alloy and contained milled coolant channels. The chambers were completed by means of an electroformed nickel closeout. The oxidant/fuel ratio for the liquid oxygen and gaseous hydrogen propellants was 6.0. The failures in the OFHC copper chambers were not typical fatigue failures but are described as creep rupture enhanced by ratcheting. The coolant channels bulged toward the chamber centerline, resulting in progressive thinning of the wall during each cycle. The failures in the Amzirc alloy chambers were caused by low-cycle thermal fatigue. The lives were much shorter than were predicted by an analytical structural analysis computer program used in conjunction with fatigue life data from isothermal test specimens, due to the uneven distribution of Zr in the chamber material.

Ultra-high temperature isothermal furnace liners (IFLS) for copper freeze point cells

NASA Astrophysics Data System (ADS)

Dussinger, P. M.; Tavener, J. P.

2013-09-01

Primary Laboratories use large fixed-point cells in deep calibration furnaces utilizing heat pipes to achieve temperature uniformity. This combination of furnace, heat pipe, and cell gives the smallest of uncertainties. The heat pipe, also known as an isothermal furnace liner (IFL), has typically been manufactured with Alloy 600/601 as the envelope material since the introduction of high temperature IFLs over 40 years ago. Alloy 600/601 is a widely available high temperature material, which is compatible with Cesium, Potassium, and Sodium and has adequate oxidation resistance and reasonable high temperature strength. Advanced Cooling Technologies, Inc. (ACT) Alloy 600/Sodium IFLs are rated to 1100°C for approximately 1000 hours of operation (based on creep strength). Laboratories interested in performing calibrations and studies around the copper freezing point (1084.62°C) were frustrated by the 1000 hours at 1100°C limitation and the fact that expensive freeze-point cells were getting stuck and/or crushed inside the IFL. Because of this growing frustration/need, ACT developed an Ultra High Temperature IFL to take advantage of the exceptional high temperature strength properties of Haynes 230.

Microinjector for blasocysts

DOEpatents

Remenyik, Carl J.; Woychik, Richard P.; Patek, David R.; Hawk, James A.; Turner, John C.

1999-01-01

An electromechanical device for driving the tip of a microinjection cannula, or needle, through the outer barrier of a blastocyst, cell, or cell nucleus for the injection of cells or other bioactive materials. Either a flexible frame or a ram moving within a base member is employed. Cannula motion is achieved by means of a piezoelectric stack and spring return system. The thrust motion over a predetermined microscopic distance is achieved without cannula setback prior to the thrust movement. Instead of specially prepared beveled and tipped needles, standard unimproved cannulas or needles can be used.

Microinjector for blasocysts

DOEpatents

Remenyik, C.J.; Woychik, R.P.; Patek, D.R.; Hawk, J.A.; Turner, J.C.

1999-03-02

An electromechanical device is disclosed for driving the tip of a microinjection cannula, or needle, through the outer barrier of a blastocyst, cell, or cell nucleus for the injection of cells or other bioactive materials. Either a flexible frame or a ram moving within a base member is employed. Cannula motion is achieved by means of a piezoelectric stack and spring return system. The thrust motion over a predetermined microscopic distance is achieved without cannula setback prior to the thrust movement. Instead of specially prepared beveled and tipped needles, standard unimproved cannulas or needles can be used. 6 figs.

Statistically Based Approach to Broadband Liner Design and Assessment

NASA Technical Reports Server (NTRS)

Jones, Michael G. (Inventor); Nark, Douglas M. (Inventor)

2016-01-01

A broadband liner design optimization includes utilizing in-duct attenuation predictions with a statistical fan source model to obtain optimum impedance spectra over a number of flow conditions for one or more liner locations in a bypass duct. The predicted optimum impedance information is then used with acoustic liner modeling tools to design liners having impedance spectra that most closely match the predicted optimum values. Design selection is based on an acceptance criterion that provides the ability to apply increasing weighting to specific frequencies and/or operating conditions. One or more broadband design approaches are utilized to produce a broadband liner that targets a full range of frequencies and operating conditions.

21 CFR 872.3250 - Calcium hydroxide cavity liner.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Calcium hydroxide cavity liner. 872.3250 Section... (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3250 Calcium hydroxide cavity liner. (a) Identification. A calcium hydroxide cavity liner is a device material intended to be applied to the interior of a...

21 CFR 872.3250 - Calcium hydroxide cavity liner.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Calcium hydroxide cavity liner. 872.3250 Section... (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3250 Calcium hydroxide cavity liner. (a) Identification. A calcium hydroxide cavity liner is a device material intended to be applied to the interior of a...

30 CFR 250.425 - What are the requirements for pressure testing liners?

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 Casing and Cementing Requirements § 250.425 What are the requirements for pressure testing liners? (a) You must test each drilling liner (and liner-lap) to a pressure...

21 CFR 872.3250 - Calcium hydroxide cavity liner.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Calcium hydroxide cavity liner. 872.3250 Section... (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3250 Calcium hydroxide cavity liner. (a) Identification. A calcium hydroxide cavity liner is a device material intended to be applied to the interior of a...

21 CFR 872.3250 - Calcium hydroxide cavity liner.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Calcium hydroxide cavity liner. 872.3250 Section... (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3250 Calcium hydroxide cavity liner. (a) Identification. A calcium hydroxide cavity liner is a device material intended to be applied to the interior of a...

21 CFR 872.3250 - Calcium hydroxide cavity liner.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Calcium hydroxide cavity liner. 872.3250 Section... (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3250 Calcium hydroxide cavity liner. (a) Identification. A calcium hydroxide cavity liner is a device material intended to be applied to the interior of a...

Azimuthal Current Density Distribution Resulting from a Power Feed Vacuum Gap in Metallic Liner Experiments at 1 MA

NASA Astrophysics Data System (ADS)

Bott-Suzuki, Simon; Cordaro, S. W.; Caballero Bendixsen, L. S.; Atoyan, L.; Byvank, T.; Potter, W.; Kusse, B. R.; Greenly, J. B.; Hammer, D. A.; Chittenden, J. P.; Jennings, C. A.

2015-11-01

We present a study investigating the initiation of plasma in solid, metallic liners where the liner thickness is large compared to the collisionless skin depth. A vacuum gap is introduced in the power feed and we investigate the effect of this on the azimuthal initiation of plasma in the liner. We present optical emission data from aluminum liners on the 1 MA, 100ns COBRA generator. We use radial and axial gated imaging and streak photography, which show a dependence of onset of emission with the size of a small power-feed vacuum gap. The evolution of ``hot-spots'' generated from breakdown vacuum gap evolves relatively slowly and azimuthal uniformity is not observed on the experimental time-scale. We also show measurements of the B-field both outside and inside the liner, using miniature Bdot probes, which show a dependence on the liner diameter and thickness, and a correlation to the details of the breakdown. These data will be compared to magneto-hydrodynamic simulations to infer how such non-uniformities may affect full liner implosion experiments.

Acoustic Characteristics of Various Treatment Panel Designs Specific to HSCT Mixer-Ejector Application

NASA Technical Reports Server (NTRS)

Salikuddin, M.; Kinzie, K.; Vu, D. D.; Langenbrunner, L. E.; Szczepkowski, G. T.

2006-01-01

The development process of liner design methodology is described in several reports. The results of the initial effort of concept development, screening, laboratory testing of various liner concepts, and preliminary correlation (generic data) are presented in a report Acoustic Characteristics of Various Treatment Panel Designs for HSCT Ejector Liner Acoustic Technology Development Program. The second phase of laboratory test results of more practical concepts and their data correlations are presented in this report (product specific). In particular, this report contains normal incidence impedance measurements of several liner types in both a static rig and in a high temperature flow duct rig. The flow duct rig allows for temperatures up to 400 F with a grazing flow up to Mach 0.8. Measurements of impedance, DC flow resistance, and in the flow rig cases, impact of the liner on boundary layer profiles are documented. In addition to liner rig tests, a limited number of tests were made on liners installed in a mixer-Ejector nozzle to confirm the performance of the liner prediction in an installed configuration.

Evaluation of Variable-Depth Liner Configurations for Increased Broadband Noise Reduction

NASA Technical Reports Server (NTRS)

Jones, M. G.; Watson, W. R.; Nark, D. M.; Howerton, B. M.

2015-01-01

This paper explores the effects of variable-depth geometry on the amount of noise reduction that can be achieved with acoustic liners. Results for two variable-depth liners tested in the NASA Langley Grazing Flow Impedance Tube demonstrate significant broadband noise reduction. An impedance prediction model is combined with two propagation codes to predict corresponding sound pressure level profiles over the length of the Grazing Flow Impedance Tube. The comparison of measured and predicted sound pressure level profiles is sufficiently favorable to support use of these tools for investigation of a number of proposed variable-depth liner configurations. Predicted sound pressure level profiles for these proposed configurations reveal a number of interesting features. Liner orientation clearly affects the sound pressure level profile over the length of the liner, but the effect on the total attenuation is less pronounced. The axial extent of attenuation at an individual frequency continues well beyond the location where the liner depth is optimally tuned to the quarter-wavelength of that frequency. The sound pressure level profile is significantly affected by the way in which variable-depth segments are distributed over the length of the liner. Given the broadband noise reduction capability for these liner configurations, further development of impedance prediction models and propagation codes specifically tuned for this application is warranted.

Modeling of Broadband Liners Applied to the Advanced Noise Control Fan

NASA Technical Reports Server (NTRS)

Nark, Douglas M.; Jones, Michael G.; Sutliff, Daniel L.

2015-01-01

The broadband component of fan noise has grown in relevance with an increase in bypass ratio and incorporation of advanced fan designs. Therefore, while the attenuation of fan tones remains a major factor in engine nacelle acoustic liner design, the simultaneous reduction of broadband fan noise levels has received increased interest. As such, a previous investigation focused on improvements to an established broadband acoustic liner optimization process using the Advanced Noise Control Fan (ANCF) rig as a demonstrator. Constant-depth, double-degree of freedom and variable-depth, multi-degree of freedom liner designs were carried through design, fabrication, and testing. This paper addresses a number of areas for further research identified in the initial assessment of the ANCF study. Specifically, incident source specification and uncertainty in some aspects of the predicted liner impedances are addressed. This information is incorporated in updated predictions of the liner performance and comparisons with measurement are greatly improved. Results illustrate the value of the design process in concurrently evaluating the relative costs/benefits of various liner designs. This study also provides further confidence in the integrated use of duct acoustic propagation/radiation and liner modeling tools in the design and evaluation of novel broadband liner concepts for complex engine configurations.

ONERA-NASA Cooperative Effort on Liner Impedance Eduction

NASA Technical Reports Server (NTRS)

Primus, Julien; Piot, Estelle; Simon, Frank; Jones, Michael G.; Watson, Willie R

2013-01-01

As part of a cooperation between ONERA and NASA, the liner impedance eduction methods developed by the two research centers are compared. The NASA technique relies on an objective function built on acoustic pressure measurements located on the wall opposite the test liner, and the propagation code solves the convected Helmholtz equation in uniform ow using a finite element method that implements a continuous Galerkin discretization. The ONERA method uses an objective function based either on wall acoustic pressure or on acoustic velocity acquired above the liner by Laser Doppler Anemometry, and the propagation code solves the linearized Euler equations by a discontinuous Galerkin discretization. Two acoustic liners are tested in both ONERA and NASA ow ducts and the measured data are treated with the corresponding impedance eduction method. The first liner is a wire mesh facesheet mounted onto a honeycomb core, designed to be linear with respect to incident sound pressure level and to grazing ow velocity. The second one is a conventional, nonlinear, perforate-over-honeycomb single layer liner. Configurations without and with ow are considered. For the nonlinear liner, the comparison of liner impedance educed by NASA and ONERA shows a sensitivity to the experimental conditions, namely to the nature of the source and to the sample width.

Status of Duct Liner Technology for Application to Aircraft Engine Nacelles

NASA Technical Reports Server (NTRS)

Parrott, Tony L.; Jones, Michael G.; Watson, Willie R.

2005-01-01

Grazing flows and high acoustic intensities impose unusual design requirements on acoustic liner treatments used in aircraft engine nacelles. Increased sound absorption efficiency (requiring increased accuracy of liner impedance specification) is particularly critical in the face of ever decreasing nacelle wall area available for liner treatments in modern, high-bypass ratio engines. This paper reviews the strategy developed at Langley Research Center for achieving a robust measurement technology that is crucial for validating impedance models for aircraft liners. Specifically, the paper describes the current status of computational and data acquisition technologies for reducing impedance in a flow duct. Comparisons of reduced impedances for a "validation liner" using 1980's and 2000's measurement technology are consistent, but show significant deviations (up to 0.5 c exclusive of liner anti-resonance region) from a first principles impedance prediction model as grazing flow centerline Mach numbers increase up to 0.5. The deviations, in part, are believed related to uncertainty in the choice of grazing flow parameters (e.g. cross-section averaged, core-flow averaged, or centerline Mach number?). Also, there may be an issue with incorporating the impedance discontinuities corresponding to the hard wall to liner interface (i.e. leading and trailing edge of test liner) within the discretized finite element model.

Development of a Multifidelity Approach to Acoustic Liner Impedance Eduction

NASA Technical Reports Server (NTRS)

Nark, Douglas M.; Jones, Michael G.

2017-01-01

The use of acoustic liners has proven to be extremely effective in reducing aircraft engine fan noise transmission/radiation. However, the introduction of advanced fan designs and shorter engine nacelles has highlighted a need for novel acoustic liner designs that provide increased fan noise reduction over a broader frequency range. To achieve aggressive noise reduction goals, advanced broadband liner designs, such as zone liners and variable impedance liners, will likely depart from conventional uniform impedance configurations. Therefore, educing the impedance of these axial- and/or spanwise-variable impedance liners will require models that account for three-dimensional effects, thereby increasing computational expense. Thus, it would seem advantageous to investigate the use of multifidelity modeling approaches to impedance eduction for these advanced designs. This paper describes an extension of the use of the CDUCT-LaRC code to acoustic liner impedance eduction. The proposed approach is applied to a hardwall insert and conventional liner using simulated data. Educed values compare well with those educed using two extensively tested and validated approaches. The results are very promising and provide justification to further pursue the complementary use of CDUCT-LaRC with the currently used finite element codes to increase the efficiency of the eduction process for configurations involving three-dimensional effects.

Variable-Depth Liner Evaluation Using Two NASA Flow Ducts

NASA Technical Reports Server (NTRS)

Jones, M. G.; Nark, D. M.; Watson, W. R.; Howerton, B. M.

2017-01-01

Four liners are investigated experimentally via tests in the NASA Langley Grazing Flow Impedance Tube. These include an axially-segmented liner and three liners that use reordering of the chambers. Chamber reordering is shown to have a strong effect on the axial sound pressure level profiles, but a limited effect on the overall attenuation. It is also shown that bent chambers can be used to reduce the liner depth with minimal effects on the attenuation. A numerical study is also conducted to explore the effects of a planar and three higher-order mode sources based on the NASA Langley Curved Duct Test Rig geometry. A four-segment liner is designed using the NASA Langley CDL code with a Python-based optimizer. Five additional liner designs, four with rearrangements of the first liner segments and one with a redistribution of the individual chambers, are evaluated for each of the four sources. The liner configuration affects the sound pressure level profile much more than the attenuation spectra for the planar and first two higher-order mode sources, but has a much larger effect on the SPL profiles and attenuation spectra for the last higher-order mode source. Overall, axially variable-depth liners offer the potential to provide improved fan noise reduction, regardless of whether the axially variable depths are achieved via a distributed array of chambers (depths vary from chamber to chamber) or a group of zones (groups of chambers for which the depth is constant).

Survivorship of Total Hip Joint Replacements Following Isolated Liner Exchange for Wear.

PubMed

Vadei, Leone; Kieser, David C; Frampton, Chris; Hooper, Gary

2017-11-01

Liner exchange for articular component wear in total hip joint replacements (THJRs) is a common procedure, often thought to be benign with reliable outcomes. Recent studies, however, suggest high failure rates of liner exchange revisions with significant complications. The primary aim of this study was, therefore, to analyze the survivorship of isolated liner exchange for articular component wear, and secondarily to assess the influence of patient demographics (gender, age, and American Society of Anaesthesiologists [ASA] ratings) on rerevisions following isolated liner exchange for wear. A retrospective review of the 15-year New Zealand Joint Registry (1999-2014) was performed, analyzing the outcomes of isolated liner exchange for articular component wear. The survivorship as defined as rerevision with component exchange was determined and 10-year Kaplan-Meier survivorship curves were constructed. These revision rates were compared to age, gender, and ASA rating groups using a log-rank test. The 10-year survivorship of THJR following liner exchange revision for liner wear was 75.3%. If a rerevision was required, the median time to rerevision was 1.33 years with a rerevision rate of 3.33 per 100 component years (95% confidence interval 2.68-4.08/100 component years). The principle reasons for rerevision were dislocation (48.4%) and acetabular component loosening (20.9%). There was no statistically significant difference in rerevision rates based on gender, age categories, or ASA scores. THJR isolated liner exchange for liner wear is not a benign procedure with a survivorship of 75.3% at 10 years. Surgeons contemplating liner exchange revisions should be cognisant of this risk and should adequately assess component position and stability preoperatively. Copyright © 2017 Elsevier Inc. All rights reserved.

Analysis of Dual Mobility Liner Rim Damage Using Retrieved Components and Cadaver Models.

PubMed

Nebergall, Audrey K; Freiberg, Andrew A; Greene, Meridith E; Malchau, Henrik; Muratoglu, Orhun; Rowell, Shannon; Zumbrunn, Thomas; Varadarajan, Kartik M

2016-07-01

The objective of this study was to assess the retentive rim of retrieved dual mobility liners for visible evidence of deformation from femoral neck contact and to use cadaver models to determine if anterior soft tissue impingement could contribute to such deformation. Fifteen surgically retrieved polyethylene liners were assessed for evidence of rim deformation. The average time in vivo was 31.4 months, and all patients were revised for reasons other than intraprosthetic dislocation. Liner interaction with the iliopsoas was studied visually and with fluoroscopy in cadaver specimens using a dual mobility system different than the retrieval study. For fluoroscopic visualization, a metal wire was sutured to the iliopsoas and wires were also embedded into grooves on the outer surface of the liner and the inner head. All retrievals showed evidence of femoral neck contact. The cadaver experiments showed that liner motion was impeded by impingement with the iliopsoas tendon in low flexion angles. When observing the hip during maximum hyperextension, 0°, 15°, and 30° of flexion, there was noticeable tenting of the iliopsoas caused by impingement with the liner. Liner rim deformation resulting from contact with the femoral neck likely begins during early in vivo function. The presence of deformation is indicative of a mechanism inhibiting mobility of the liner. The cadaver studies showed that liner motion could be impeded because of its impingement with the iliopsoas. Such soft tissue impingement may be one mechanism by which liner motion is routinely inhibited, which can result in load transfer from the neck to the rim. Copyright © 2015 Elsevier Inc. All rights reserved.

Measurement of telomerase activity in dog tumors.

PubMed

Yazawa, M; Okuda, M; Setoguchi, A; Nishimura, R; Sasaki, N; Hasegawa, A; Watari, T; Tsujimoto, H

1999-10-01

Telomeres are specific structures present at the end of liner chromosomes. DNA polymerase can not synthesize the end of liner DNA and, as a result, the telomeres become progressively shortened by successive cell divisions. To overcome the end replication problem, telomerase adds new telomeric sequences to the end of chromosomal DNA. The enzyme activity is undetectable in most normal human adult somatic cells, in which shortening of the telomere is thought to limit the somatic-cell life span. In contrast to normal somatic cells, many human tumors possess telomerase activity. The present study looked at whether telomerase activity might serve as a marker for canine tumors. Telomerase activity was measured using the telomeric repeat amplification protocol assay. Normal dog somatic tissues showed little or no telomerase activity, while normal testis exhibited a high level of telomerase activity. We measured telomerase activity in tumor samples from 45 dogs; 21 mammary gland tumors, 16 tumors developed in the skin and oral cavity, 7 vascular tumors and 1 Sertoli cell tumor. Greater than 95% of the tumor samples contained telomerase activity (3-924 U/2 micrograms protein). The results obtained in this study indicated that telomerase should be a useful diagnostic marker for a variety of dog tumors, and it may serve as a target for antitumor chemotherapy.

Extent of fungal growth on fiberglass duct liners with and without biocides under challenging environmental conditions.

PubMed

Samimi, Behzad S; Ross, Kristen

2003-03-01

Eight brands of fiberglass duct liners, including three that contained biocides, were exposed to challenging environmental conditions that would promote fungal growth. Twenty-four rectangular sheet metal ducts in three groups of eight ducts per group were lined with the eight selected liners. Each group of ducts was exposed to one of the three test conditions within an environmental chamber for a period of 15 days. These conditions were a) 75 percent RH, b) 75 percent RH plus water spray, c) 75 percent RH plus dry nutrient, and d) 75 percent RH plus water plus nutrient. Viable spores of Aspergillus niger were aerosolized into each duct as seed. On the 16th day, air and surface samples for fungal spores were collected from inside ducts. The results of air sampling using N6 sampler and visual inspection indicated that two out of three biocide-containing liners, Permacote and Toughgard, inhibited fungal growth but only under condition A. The third biocide-containing liner, Aeroflex Plus, was effective even when it was wet (conditions A and B). All three biocide-containing liners failed to inhibit fungal growth under conditions C and D. Among the five other types of liners that did not contain biocides, ATCO Flex with a smooth Mylar coating was more preferable, exhibiting lower fungal activity during conditions A, B, and C. All liners failed under condition D when nutrient and water were added together. Surface sampling using adhesive tape failed to produce representative results, apparently due to rough/porous surface of duct liners. It was concluded that duct liners with biocide treatment could be less promoting to microbial growth under high humidity as long as their surfaces remain clean and water-free. A liner with an impermeable and smooth surface seems to be less subject to microbial growth under most conditions than biocide-containing liners having porous and/or rough surfaces.

Effect of flowable composite liner and glass ionomer liner on class II gingival marginal adaptation of direct composite restorations with different bonding strategies.

PubMed

Aggarwal, Vivek; Singla, Mamta; Yadav, Suman; Yadav, Harish

2014-05-01

The purpose of the present study was to comparatively evaluate the effect of flowable composite resin liner and resin modified glass ionomer liner on gingival marginal adaptation of class II cavities restored using three bonding agents (Single Bond 3M ESPE, One Coat Self Etching Bond Coltene Whaledent; Adper Easy Bond Self-Etch Adhesive 3M ESPE) and respective composite resins, under cyclic loading. The marginal adaptation was evaluated in terms of 'continuous margin' (CM) at the gingival margin. Ninety class II cavities with margins extending 1mm below the cement-enamel junction were prepared in extracted mandibular third molars. The samples were divided into three groups: no liner placement; 0.5-1mm thick flowable resin liner placement (Filtek Z350 XT flowable resin) on gingival floor and; light cure glass ionomer (Ketac N100) liner. The groups were further subdivided into three sub-groups on the basis of the bonding agents used. Cavities were restored with composite resins (Z350 for Single Bond and Adper Easy Bond; and Synergy D6 Universal, for One Coat Self Etching Bond) in 2mm increments and the samples were mechanically loaded (60N, 1,50,000 cycles). Marginal adaptation was evaluated using a low vacuum scanning electron microscope. Statistical analysis was done with two way ANOVA with Holm-Sidak's correction for multiple comparisons. Placement of flowable composite liner significantly improved the CM values of Single Bond (78±11%) and One Coat Self Etching Bond (77±9%) compared with no liner group, but the values of CM of Adper Easy Bond were not improved (61±12%). Placement of glass ionomer liner significantly improved the values of CM in all the sub-groups (78±9%, 72±10% and 77±10% for Single Bond, One Coat Self Etching Bond & Adper Easy Bond respectively) compared with no liner group. Placement of liners improved the values of 'continuous margin' in the gingival floor of the proximal cavities restored with composite resins using different bonding agent. Placement of flowable composite liner or glass ionomer liner will improve the marginal integrity of composite restorations using etch-and-rinse and two bottle-two step self etch adhesives. To improve the marginal integrity of a single bottle adhesive, glass ionomer liner should be applied. Copyright © 2014 Elsevier Ltd. All rights reserved.

Effect of ultra-thin liner materials on copper nucleation/wetting and copper grain growth

NASA Astrophysics Data System (ADS)

Mueller, Justin E.

One of the key challenges facing future integrated circuit copper (Cu) interconnect manufacturing is to achieve uniform coverage of PVD Cu seed layer at minimum thickness on a liner and barrier. We have therefore characterized the nucleation and wetting of PVD Cu on various liner surfaces by monitoring in-situ the film's electrical conductance during the initial stages of deposition (0 to 25 nm). Our results showed that the Cu wetting is sensitive to the Cu/liner interfacial properties, while the nucleation depends on the liner microstructure. It was found that a ruthenium (Ru) liner has a good Cu wetting characteristic and allows at the onset nearly layer by layer Cu growth. Because of good wetting, Cu growth is not significantly affected by Ru liner grain size. Tantalum (Ta), however, exhibits poor Cu wetting, which results in an initial stage of three dimensional island growth of Cu. In this case, Cu island coalescing occurs sooner, at a smaller Cu film thickness, when the nucleation site density is increased with a smaller grain size Ta liner. To optimize the seed layer's conductance and step coverage, a liner with combined properties of Ta (for adhesion and barrier formation) and Ru (for wetting and grain growth) may be desired. A hybrid magnetron target has been developed for depositing TaRu liner films at various compositions. The microstructure of the compound liners and their effects on the overgrown Cu seed layer over a wide range of TaRu composition is presented. It was found that below 80% Ru concentration, TaRu films are amorphous. An amorphous liner results in poor Cu nucleation as compared with a crystalline Ta or Ru liner. A comparison of the microstructure of thin Cu films deposited on bcc alpha-Ta and tetragonal beta-Ta surfaces has been carried out. Cu resistivity is lower by 10-15%, accompanied by larger Cu grain size, in as-deposited Cu films of various thickness' (30-120 nm) on beta-Ta as compared to those deposited on alpha-Ta. This is due to the presence of an epitaxial relationship between Cu (111) and beta-Ta (002) planes. After annealing, the difference was only seen in films thinner than 60 nm. Results were confirmed when Cu film resistance was measured in-situ during deposition on each phase of Ta liner. Serpentine interconnect line structures of various line widths and aspect ratios were fabricated using either alpha- or beta-Ta liners, and subjected to a similar heat treatment. Results showed a similar ˜10% lower resistivity in the thinnest interconnects (˜40 nm) when a beta-Ta liner was used.

30 CFR 250.425 - What are the requirements for pressure testing liners?

Code of Federal Regulations, 2014 CFR

2014-07-01

..., DEPARTMENT OF THE INTERIOR OFFSHORE OIL AND GAS AND SULPHUR OPERATIONS IN THE OUTER CONTINENTAL SHELF Oil and Gas Drilling Operations Casing and Cementing Requirements § 250.425 What are the requirements for pressure testing liners? (a) You must test each drilling liner (and liner-lap) to a pressure at least equal...

30 CFR 250.425 - What are the requirements for pressure testing liners?

Code of Federal Regulations, 2013 CFR

2013-07-01

..., DEPARTMENT OF THE INTERIOR OFFSHORE OIL AND GAS AND SULPHUR OPERATIONS IN THE OUTER CONTINENTAL SHELF Oil and Gas Drilling Operations Casing and Cementing Requirements § 250.425 What are the requirements for pressure testing liners? (a) You must test each drilling liner (and liner-lap) to a pressure at least equal...

30 CFR 250.425 - What are the requirements for pressure testing liners?

Code of Federal Regulations, 2012 CFR

2012-07-01

..., DEPARTMENT OF THE INTERIOR OFFSHORE OIL AND GAS AND SULPHUR OPERATIONS IN THE OUTER CONTINENTAL SHELF Oil and Gas Drilling Operations Casing and Cementing Requirements § 250.425 What are the requirements for pressure testing liners? (a) You must test each drilling liner (and liner-lap) to a pressure at least equal...

Low thermal flux glass-fiber tubing for cryogenic service

NASA Technical Reports Server (NTRS)

Hall, C. A.; Spond, D. E.

1977-01-01

This paper describes analytical techniques, fabrication development, and test results for composite tubing that has many applications in aerospace and commercial cryogenic installations. Metal liner fabrication is discussed in detail with attention given to resistance-welded liners, fusion-welded liners, chem-milled tubing liners, joining tube liners and end fittings, heat treatment and leak checks. Composite overwrapping, a second method of tubing fabrication, is also discussed. Test programs and analytical correlation are considered along with composite tubing advantages such as minimum weight, thermal efficiency and safety and reliability.

One-dimensional magnetohydrodynamics of a cylindrical liner imploded by an azimuthal magnetic field and compressing an axial field

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

Hamann, F., E-mail: franck.hamann@cea.fr; Combis, P.; Videau, L.

The one-dimensional magnetohydrodynamics of a plasma cylindrical liner is addressed in the case of a two components magnetic field. The azimuthal component is responsible for the implosion of the liner and the axial field is compressed inside the liner. A complete set of analytical profiles for the magnetic field components, the density, and the local velocity are proposed at the scale of the liner thickness. Numerical simulations are also presented to test the validity of the analytical formulas.

Wheel liner design for improved sound and structural performances

NASA Astrophysics Data System (ADS)

Oltean, Alexandru; Diaconescu, Claudiu; Tabacu, Ştefan

2017-10-01

Vehicle noise is composed mainly of wheel-road noise and noise from the power unit. At low speeds power unit noise dominates while at high speeds wheel-road noise dominates as wheel-road noise level increases approximately logarithmically with speed. The wheel liner is designed as a component of the vehicle that has a multiple role. It has to prevent the dirt or water from the road surface that are engaged by the wheel to access the engine/front bay. Same time it has the important role to reduce perceived noised in the passenger’s compartment that comes from the wheel-road interaction. Progress in plastic injection moulding technology allowed for new structures to be developed - nonwoven materials in combination with a PP based carrier structure which benefits from a cell structure caused by MuCell injection moulding. The results are light parts with increased sound absorption performances. An adapted combination of materials and production processes can provide the solution for stiff yet soundproofing structures valued for modern vehicles. Sound absorption characteristics of materials used for wheel liners applications were reported in this study. Different polypropylene and polyester fibre-based thermally bonded nonwovens varying in weight and thickness were investigated. Having as a background the performances of the nonwoven material the microcellular structure was part of the analysis. Acoustical absorptive behaviour was explained by analysing the results obtained using the impedance tube and correlating with the knowledge of materials structure.

Experimental Validation of Numerical Simulations for an Acoustic Liner in Grazing Flow

NASA Technical Reports Server (NTRS)

Tam, Christopher K. W.; Pastouchenko, Nikolai N.; Jones, Michael G.; Watson, Willie R.

2013-01-01

A coordinated experimental and numerical simulation effort is carried out to improve our understanding of the physics of acoustic liners in a grazing flow as well our computational aeroacoustics (CAA) method prediction capability. A numerical simulation code based on advanced CAA methods is developed. In a parallel effort, experiments are performed using the Grazing Flow Impedance Tube at the NASA Langley Research Center. In the experiment, a liner is installed in the upper wall of a rectangular flow duct with a 2 inch by 2.5 inch cross section. Spatial distribution of sound pressure levels and relative phases are measured on the wall opposite the liner in the presence of a Mach 0.3 grazing flow. The computer code is validated by comparing computed results with experimental measurements. Good agreements are found. The numerical simulation code is then used to investigate the physical properties of the acoustic liner. It is shown that an acoustic liner can produce self-noise in the presence of a grazing flow and that a feedback acoustic resonance mechanism is responsible for the generation of this liner self-noise. In addition, the same mechanism also creates additional liner drag. An estimate, based on numerical simulation data, indicates that for a resonant liner with a 10% open area ratio, the drag increase would be about 4% of the turbulent boundary layer drag over a flat wall.

The effect of accelerated ageing on colour stability of visible light-cured (VLC) chairside denture liners.

PubMed

Kostoulas, Ioannis; Polyzois, Gregory; Mitsoudis, Anastasios; Kavoura, Victoria; Frangou, Maria

2012-06-01

The purpose of this study was to assess the colour stability of seven visible light-cured (VLC) hard and soft denture liners by an in vitro accelerated ageing test and compare them with two autopolymerised hard and soft liners. Ten specimens of each material were fabricated. The initial colour was measured with a tri-stimulus colorimeter. One set of five specimens was placed in distilled water at 37°C in the dark for 15 days, while the remaining were subjected to UV/visible light-accelerated ageing initially for 24 h and then for 144 h. Colour change (ΔΕ) was calculated. Data were statistically analysed by anova, Tukey and t-tests at α = 0.05. All the liners showed clinically acceptable colour change (ΔΕ ≤ 6.8) in distilled water. The colour changes after ageing for Triad DuaLine, Lightdon U, Ufi Gel H and Light Liner Hard were clinically unacceptable (ΔΕ ≥ 6.8), whereas LightLiner Soft, Astron LC Soft, Triad Resiline and Flexacryl Soft presented slighter and clinically acceptable colour change (ΔΕ ≤ 6.8). Accelerated ageing affected significantly the colour stability of all denture liners tested except Astron LC Soft. Soft VLC denture liners were more colour-stable than hard VLC liners. © 2011 The Gerodontology Society and John Wiley & Sons A/S.

Evaluation of Parallel-Element, Variable-Impedance, Broadband Acoustic Liner Concepts

NASA Technical Reports Server (NTRS)

Jones, Michael G.; Howerton, Brian M.; Ayle, Earl

2012-01-01

Recent trends in aircraft engine design have highlighted the need for acoustic liners that provide broadband sound absorption with reduced liner thickness. Three such liner concepts are evaluated using the NASA normal incidence tube. Two concepts employ additive manufacturing techniques to fabricate liners with variable chamber depths. The first relies on scrubbing losses within narrow chambers to provide acoustic resistance necessary for sound absorption. The second employs wide chambers that provide minimal resistance, and relies on a perforated sheet to provide acoustic resistance. The variable-depth chambers used in both concepts result in reactance spectra near zero. The third liner concept employs mesh-caps (resistive sheets) embedded at variable depths within adjacent honeycomb chambers to achieve a desired impedance spectrum. Each of these liner concepts is suitable for use as a broadband sound absorber design, and a transmission line model is presented that provides good comparison with their respective acoustic impedance spectra. This model can therefore be used to design acoustic liners to accurately achieve selected impedance spectra. Finally, the effects of increasing the perforated facesheet thickness are demonstrated, and the validity of prediction models based on lumped element and wave propagation approaches is investigated. The lumped element model compares favorably with measured results for liners with thin facesheets, but the wave propagation model provides good comparisons for a wide range of facesheet thicknesses.

High pressure storage vessel

DOEpatents

Liu, Qiang

2013-08-27

Disclosed herein is a composite pressure vessel with a liner having a polar boss and a blind boss a shell is formed around the liner via one or more filament wrappings continuously disposed around at least a substantial portion of the liner assembly combined the liner and filament wrapping have a support profile. To reduce susceptible to rupture a locally disposed filament fiber is added.

76 FR 45541 - Procurement List; Additions

Federal Register 2010, 2011, 2012, 2013, 2014

2011-07-29

...-1309--Can Liner, Low Density, Gusset Cut, Clear, 12x8x22. NSN: 8105-00-NIB-1322--Can Liner, Low Density, Star Seal, Clear, 24x33. NSN: 8105-00-NIB-1323--Can Liner, Low Density, Star Seal, Clear, 33x44. NSN: 8105-00-NIB-1324--Can Liner, Low Density, Star Seal, Clear, 40x48. NPA: Envision, Inc., Wichita, KS...

Color Stability of Silicone or Acrylic Denture Liners: An in Vitro Investigation

PubMed Central

Ergun, Gulfem; Nagas, Isil Cekic

2007-01-01

Objectives The aim of this study was to compare the color stability of three acrylic based hard liners (Ufi gel hard, Dura-Liner II, Tokuso Rebase) and two silicone based soft liners (Ufi gel permanent, Molloplast B) by using the colorimeter. Methods Sixty disc-shaped samples, with uniform size of 10 mm diameter and 2 mm in thickness were fabricated for each material. Thirty samples were made as control group in distilled water and the remaining thirty samples were weathered in accelerated aging chamber. Color measurements were made before and after distilled water and aging. Data were statistically analyzed using nonparametric Kruskal-Wallis and Mann-Whitney U tests. Results Data showed that there are significant differences among materials in both after distilled water and aging treatments (P<.001). These results indicated that the most discolored liner material was Dura Liner II after aging (ΔE*=16.30) and the least discolored material was Ufi gel permanent after distilled water (ΔE*=0.41). Conclusions Based on the results of this study, silicone based liner materials are considered to be more color stable than acrylic based liner materials. PMID:19212558

Further Development and Assessment of a Broadband Liner Optimization Process

NASA Technical Reports Server (NTRS)

Nark, Douglas M.; Jones, Michael G.; Sutliff, Daniel L.

2016-01-01

The utilization of advanced fan designs (including higher bypass ratios) and shorter engine nacelles has highlighted a need for increased fan noise reduction over a broader frequency range. Thus, improved broadband liner designs must account for these constraints and, where applicable, take advantage of advanced manufacturing techniques that have opened new possibilities for novel configurations. This work focuses on the use of an established broadband acoustic liner optimization process to design a variable-depth, multi-degree of freedom liner for a high speed fan. Specifically, in-duct attenuation predictions with a statistical source model are used to obtain optimum impedance spectra over the conditions of interest. The predicted optimum impedance information is then used with acoustic liner modeling tools to design a liner aimed at producing impedance spectra that most closely match the predicted optimum values. The multi-degree of freedom design is carried through design, fabrication, and testing. In-duct attenuation predictions compare well with measured data and the multi-degree of freedom liner is shown to outperform a more conventional liner over a range of flow conditions. These promising results provide further confidence in the design tool, as well as the enhancements made to the overall design process.

Energy transfer through a multi-layer liner for shaped charges

DOEpatents

Skolnick, Saul; Goodman, Albert

1985-01-01

This invention relates to the determination of parameters for selecting materials for use as liners in shaped charges to transfer the greatest amount of energy to the explosive jet. Multi-layer liners constructed of metal in shaped charges for oil well perforators or other applications are selected in accordance with the invention to maximize the penetrating effect of the explosive jet by reference to four parameters: (1) Adjusting the explosive charge to liner mass ratio to achieve a balance between the amount of explosive used in a shaped charge and the areal density of the liner material; (2) Adjusting the ductility of each layer of a multi-layer liner to enhance the formation of a longer energy jet; (3) Buffering the intermediate layers of a multi-layer liner by varying the properties of each layer, e.g., composition, thickness, ductility, acoustic impedance and areal density, to protect the final inside layer of high density material from shattering upon impact of the explosive force and, instead, flow smoothly into a jet; and (4) Adjusting the impedance of the layers in a liner to enhance the transmission and reduce the reflection of explosive energy across the interface between layers.

Hard X-Ray Emission and the Ionizing Source in LINERs

NASA Technical Reports Server (NTRS)

Terashima, Yuichi; Ho, Luis C.; Ptak, Andrew F.

2000-01-01

We report X-ray fluxes in the 2-10 keV band from LINERs (low-ionization nuclear emission-line regions) and low-luminosity Seyfert galaxies obtained with the ASCA satellite. Observed X-ray luminosities are in the range between 4 x 10(exp 39) and 5 x 10(exp 41) ergs/s, which are significantly smaller than that of the "classical" low-luminosity Seyfert 1 galaxy NGC 4051. We found that X-ray luminosities in 2-10 keV of LINERs with broad H.alpha emission in their optical spectra (LINER 1s) are proportional to their Ha luminosities. This correlation strongly supports the hypothesis that the dominant ionizing source in LINER 1s is photoionization by hard photons from low-luminosity AGNs. On the other hand, the X-ray luminosities of most LINERs without broad H.alpha emission (LINER 2s) in our sample are lower than LINER 1s at a given H.alpha luminosity. The observed X-ray luminosities in these objects are insufficient to power their H.alpha luminosities, suggesting that their primary ionizing source is other than an AGN, or that an AGN, if present, is obscured even at energies above 2 keV.

Early time studies of cylindrical liner implosions at 1 MA on COBRA

NASA Astrophysics Data System (ADS)

Atoyan, L.; Byvank, T.; Cahill, A. D.; Hoyt, C. L.; de Grouchy, P. W. L.; Potter, W. M.; Kusse, B. R.; Hammer, D. A.

2014-12-01

Tests of the magnetized liner inertial fusion (MagLIF) concept will make use of the 27 MA Z machine at Sandia National Laboratories, Albuquerque, to implode a cylindrical metal liner to compress and heat preheated, magnetized plasma contained within it. While most pulsed power machines produce much lower currents than the Z-machine, there are issues that can still be addressed on smaller scale facilities. Recent work on the Cornell Beam Research Accelerator (COBRA) has made use of 10 mm long and 4 mm diameter metal liners having different wall thicknesses to study the initiation of plasma on the liner's surface as well as axial magnetic field compression [P.-A. Gourdain et al., Nucl. Fusion 53, 083006 (2013)]. This report presents experimental results with non-imploding liners, investigating the impact the liner's surface structure has on initiation and ablation. Extreme ultraviolet (XUV) imaging and optical 12 frame camera imaging were used to observe and assess emission non-uniformities as they developed. Axial and side-on interferometry was used to determine the distribution of plasma near the liner surface, including the impact of non-uniformities during the plasma initiation and ablation phases of the experiments.

Design of thermal protection system for 8 foot HTST combustor

NASA Technical Reports Server (NTRS)

Moskowitz, S.

1973-01-01

The combustor in the 8-foot high temperature structures tunnel at the NASA-Langley Research Center has encountered cracking over a period of 50-250 tunnel tests within a limited range of the required operating envelope. A program was conducted which analyzed the failed combustor liner hardware and determined that the mechanism of failure was vibratory fatigue. A vibration damper system using wave springs located axially between the liner T-bar and the liner support was designed as an intermediate solution to extend the life of the current two-pass regenerative air-cooled liner. The effects of liner wall thickness, cooling air passage height, stiffener ring geometry, reflective coatings, and liner material selection were investigated for these designs. Preliminary layout design arrangements including the external water-cooling system requirements, weight estimates, installation requirements and preliminary estimates of manufacturing costs were prepared for the most promissing configurations. A state-of-the-art review of thermal barrier coatings and an evaluation of reflective coatings for the gasside surface of air-cooled liners are included.

A framework for a decision support system for municipal solid waste landfill design.

PubMed

Verge, Ashley; Rowe, R Kerry

2013-12-01

A decision support system (Landfill Advisor or LFAdvisor) was developed to integrate current knowledge of barrier systems into a computer application to assist in landfill design. The program was developed in Visual Basic and includes an integrated database to store information. LFAdvisor presents the choices available for each liner component (e.g. leachate collection system, geomembrane liner, clay liners) and provides advice on their suitability for different situations related to municipal solid waste landfills (e.g. final cover, base liner, lagoon liner). Unique to LFAdvisor, the service life of each engineered component is estimated based on results from the latest research. LFAdvisor considers the interactions between liner components, operating conditions, and the existing site environment. LFAdvisor can be used in the initial stage of design to give designers a good idea of what liner components will likely be required, while alerting them to issues that are likely to arise. A systems approach is taken to landfill design with the ultimate goal of maximising long-term performance and service life.

A Conventional Liner Acoustic/Drag Interaction Benchmark Database

NASA Technical Reports Server (NTRS)

Howerton, Brian M.; Jones, Michael G.

2017-01-01

The aerodynamic drag of acoustic liners has become a significant topic in the design of such for aircraft noise applications. In order to evaluate the benefits of concepts designed to reduce liner drag, it is necessary to establish the baseline performance of liners employing the typical design features of conventional configurations. This paper details a set of experiments in the NASA Langley Grazing Flow Impedance Tube to quantify the relative drag of a number of perforate-over-honeycomb liner configurations at flow speeds of M=0.3 and 0.5. These conventional liners are investigated to determine their resistance factors using a static pressure drop approach. Comparison of the resistance factors gives a relative measurement of liner drag. For these same flow conditions, acoustic measurements are performed with tonal excitation from 400 to 3000 Hz at source sound pressure levels of 140 and 150 dB. Educed impedance and attenuation spectra are used to determine the interaction between acoustic performance and drag.

Energy efficient engine pin fin and ceramic composite segmented liner combustor sector rig test report

NASA Technical Reports Server (NTRS)

Dubiel, D. J.; Lohmann, R. P.; Tanrikut, S.; Morris, P. M.

1986-01-01

Under the NASA-sponsored Energy Efficient Engine program, Pratt and Whitney has successfully completed a comprehensive test program using a 90-degree sector combustor rig that featured an advanced two-stage combustor with a succession of advanced segmented liners. Building on the successful characteristics of the first generation counter-parallel Finwall cooled segmented liner, design features of an improved performance metallic segmented liner were substantiated through representative high pressure and temperature testing in a combustor atmosphere. This second generation liner was substantially lighter and lower in cost than the predecessor configuration. The final test in this series provided an evaluation of ceramic composite liner segments in a representative combustor environment. It was demonstrated that the unique properties of ceramic composites, low density, high fracture toughness, and thermal fatigue resistance can be advantageously exploited in high temperature components. Overall, this Combustor Section Rig Test program has provided a firm basis for the design of advanced combustor liners.

Pocketing mechanics of SRM nozzle liner

NASA Technical Reports Server (NTRS)

Verderaime, V. S.

1986-01-01

A systems approach was adopted to study the pocketing phenomena on a solid rocket nozzle liner. The classical thermoelastic analysis was used to identify marginally strained regions on the composite liner erosion surface and at a depth coincident with the peak value of the across ply coefficient of thermal expansion. A failure criterion was introduced which included a thermal term and permitted failure assessment over the charred liner. The method was verified by satisfactory application to a reported related experiment. Liner pocketing mechanism was attributed to very localized material degradation caused during manufacturing process either by reduction of fiber strength and/or by concentration of resin volume fraction. Pocketing scenario over the degraged material was constructed with supporting formulation to predict size of fissures with respect to degraded material size and location in the liner and with burn time. Sensitivities of liner material parameters were determined to influence test programs designed to update mechanical data base of carbon cloth phenolic over the char temperature range.

The Nature of the Energy Source in LINER's

NASA Technical Reports Server (NTRS)

Colina, L.; Koratkar, Anuradha

1996-01-01

LINER's (low-ionization nuclear emission-line regions) are found in about 30% of all bright galaxies, including luminous infrared galaxies. They form a heterogeneous class powered by a variety of ionizing mechanisms such as low-luminosity AGNs (active galactic nuclei), starbursts, shocks, or any combination of these. In early-type spirals, LINER's are powered by a low-luminosity AGN, or by an AGN surrounded by circumnuclear star-forming regions. In luminous infrared galaxies, LINER's are powered by starbursts with associated wind-related extended shocks, and an AGN may play a minor role, if any. LINER's in some FR I radio galaxies show strong evidence for the presence of a massive central black hole, and there are indications for the existence of shocks in the nuclear disks of these galaxies. Yet, the dominant ionizing mechanism for LINER's in radio-quiet ellipticals and FR I host galaxies is still unclear. Multifrequency high spatial resolution imaging and spectroscopy are essential to discriminate among the different ionizing mechanisms present in LINER's.

Correlating shaped charge performance with processing conditions and microstructure of an aluminum alloy 1100 liner enabled by a new method to arrest nascent jet formation

NASA Astrophysics Data System (ADS)

Scheid, James Eric

Aluminum-lined shaped charges are used in special applications where jet and / or slug residue in the target is undesired. The three different microstructures of the aluminum liners studied herein resulted from three different manufacturing interpretations of the same design. One interpretation was completely machining the liners from best available annealed round stock. The second was to cold-forge the liners from annealed round-stock in an open-die forge to near-final dimensions, and then machine the liners to the final dimensions. The third variant in this study was to use the above forged liner, but with annealing after the machining. These three manufacturing choices resulted in significant variations in shaped charge performance. The goal of this research was to clarify the relationships between the liner metal microstructure and properties, and the corresponding shaped charge dynamic flow behavior. What began as an investigation into user-reported performance problems associated inherently with liner manufacturing processes and resultant microstructure, resolved into new understandings of the relationships between aluminum liner microstructure and shaped charge collapse kinetics. This understanding was achieved through an extensive literature review and the comprehensive characterization of the material properties of three variants of an 1100 aluminum shaped charge liner with a focus on collapse and nascent jet formation. The machined liner had a microstructure with large millimeter-sized grains and fine particles aligned in bands parallel to the charge axis. The forged liner microstructure consisted of very small one micrometer-sized (1 mum) subgrains and fine particles aligned largely in bands elongated parallel to the liner contour. The annealed liner was characterized by ten micrometer (10 mum) sized equiaxed grains with residual fine particles in the forged alignment. This characterization was enabled by the development, execution and validation of a custom explosive experiment that delivered meaningful, full-scale shock deformed samples for analysis. The experiment arrested the collapse of actual, as-fabricated liners in the first microseconds of development. This experiment, performed with only 2% of the explosive mass of the full charge, revealed new insights into material-dependent variations in liner collapse including a striking image of the formation of a shaped charge jet axial hole. The highly strain-hardened and elongated forged liner was the best performer of the three. Less energy from the explosive was dissipated by dislocation generation. This translated to more efficient flow whereas the softer materials behaved as shock absorbers delaying flow. A set of hypotheses was formulated and critiqued based on these observations. The key findings were the effects of grain size, and shear bands induced in the microstructure through cold work enabled efficient liner flow. These bands provide highly localized dislocation highways enabling the matrix adjacent to the bands to deform plastically at higher velocity. Where such bands are unavailable, the pressure must first develop bands of smaller grains, thus decreasing energy available for flow. Collapse velocities were then associated with the number of shear bands, the organization of mobile dislocations, material strain, and liner geometry. Microstructures with the ability to deform with the direction of liner collapse at lower stresses will form jets with a higher velocity and elongate earlier. The effect is higher performance at shorter standoffs. This relationship can be used to predict material behavior under explosive load, guiding engineering choices while designing with respect to anticipated shock loading. The explosive experiment designed here has obvious application in refining the performance of other warheads, and in the hydrodynamic modeling of material properties.

Combustor for a low-emissions gas turbine engine

DOEpatents

Glezer, Boris; Greenwood, Stuart A.; Dutta, Partha; Moon, Hee-Koo

2000-01-01

Many government entities regulated emission from gas turbine engines including CO. CO production is generally reduced when CO reacts with excess oxygen at elevated temperatures to form CO2. Many manufactures use film cooling of a combustor liner adjacent to a combustion zone to increase durability of the combustion liner. Film cooling quenches reactions of CO with excess oxygen to form CO2. Cooling the combustor liner on a cold side (backside) away from the combustion zone reduces quenching. Furthermore, placing a plurality of concavities on the cold side enhances the cooling of the combustor liner. Concavities result in very little pressure reduction such that air used to cool the combustor liner may also be used in the combustion zone. An expandable combustor housing maintains a predetermined distance between the combustor housing and combustor liner.

Modular liquid-cooled helmet liner for thermal comfort

NASA Technical Reports Server (NTRS)

Williams, B. A.; Shitzer, A.

1974-01-01

A modular liquid-cooled helmet liner made of eight form-fitting neoprene patches was constructed. The liner was integrated into the sweatband of an Army SPH-4 helicopter aircrew helmet. This assembly was tested on four subjects seated in a hot (47 C), humid (40%) environment. Results indicate a marked reduction in the rate of increase of physiological body functions. Rectal temperature, weight loss, heart rate, and strain indices are all reduced to approximately 50% of uncooled levels. The cooling liner removed from 10% to 30% of total metabolic heat produced. This study also demonstrated the technical feasilibity of using a cooling liner in conjunction with a standard hard helmet. Potential applications of the cooling liner in thermally stressful environments are numerous, notably for helicopter and other aircrews.

Comparison of primary zone combustor liner wall temperatures with calculated predictions

NASA Technical Reports Server (NTRS)

Norgren, C. T.

1973-01-01

Calculated liner temperatures based on a steady-state radiative and convective heat balance at the liner wall were compared with experimental values. Calculated liner temperatures were approximately 8 percent higher than experimental values. A radiometer was used to experimentally determine values of flame temperature and flame emissivity. Film cooling effectiveness was calculated from an empirical turbulent mixing expression assuming a turbulent mixing level of 2 percent. Liner wall temperatures were measured in a rectangular combustor segment 6 by 12 in. and tested at pressures up to 26.7 atm and inlet temperatures up to 922 K.

Comparison of Acoustic Impedance Eduction Techniques for Locally-Reacting Liners

NASA Technical Reports Server (NTRS)

Jones, M. G.; Parrott, T. L.; Watson, W. R.

2003-01-01

Typical acoustic liners used in current aircraft inlets and aft-fan ducts consist of some type of perforated facesheet bonded to a honeycomb core. A number of techniques for determining the acoustic impedance of these locallyreacting liners have been developed over the last five decades. In addition, a number of models have been developed to predict the acoustic impedance of locallyreacting liners in the presence of grazing flow, and to use that information together with aeroacoustic propagation codes to assess the noise absorption provided by these liners. These prediction models have incorporated the results from databases acquired with specific impedance eduction techniques. Thus, while these prediction models are acceptable for liners that are similar to those tested in these databases, their application to new liner configurations must be viewed with caution. The primary purpose of this paper is to provide a comparison of impedance eduction techniques that have been implemented at various aerospace research laboratories in the United States (NASA Langley Research Center, General Electric Aircraft Engines, B. F. Goodrich and Boeing). A secondary purpose is to provide data for liner configurations that extend the porosity range beyond that which has been previously used in common aircraft engine nacelles. Two sets of liners were designed to study the effects of three parameters: perforate hole diameter, facesheet thickness and porosity. These two sets of liners were constructed for testing in each of the laboratories listed above. The first set of liners was designed to fit into the NASA Langley and Boeing test facilities. The second set was designed to fit into the General Electric Aircraft Engines and B. F. Goodrich test facilities. By using the same parent material, both sets of liners were identical to within the limits of material and fabrication variability. Baseline data were obtained in the normal incidence impedance tubes at NASA Langley and B. F. Goodrich. The results were found to compare extremely well. The samples were then tested in the grazing flow ducts of each of the four laboratories. Perhaps the most significant result of these comparisons is that the educed acoustic resistances for the liners used in this study increase as the mean flow profile is modified from uniform to 3-D shear. This realization has demonstrated the need for an frequency-dependent impedance eduction technique that incorporates 3-D shear flow and is efficient.

The effect of release liner materials on adhesive contaminants, paper recycling and recycled paper properties

Treesearch

Richard Venditti; Richard Gilbert; Andy Zhang; Said Abubakr

2000-01-01

Release liner waste material is found in post-consumer waste streams and is also a significant component of the preconsumer waste stream generated in the manufacturing of adhesive products. To date, very little has been reported pertaining to the behavior of release liner in paper recycling. In this study, the effect of the release liner material on the behavior of...

LINER FOR EXTRUSION BILLET CONTAINERS

DTIC Science & Technology

Shrink-fit assembly device for buildup of ceramic-coated liner and sleeve assemblies was tested and modified to develop desired temperatures and...preliminary evaluation of suitability for extrusion liner use. Procedures were developed for welding short, hollow ceramic cylinders of high-strength metal...carbides and borides to form a ceramic extrusion liner of suitable length. Disassembly tooling for rapid separation of shrink-fitted sleeves from a worn

Molding Helmet Liners from Nylon Cloth Made from 1050 Denier Type 700 Nylon Yarns

DTIC Science & Technology

Helmet liners were satisfactorily molded from 14 ounce, 2 x 2 basket- weave nylon fabric made of 1050 denier, 168 filaments, 3 to 4 Z turns per inch...type 700 nylon yarn. These helmets liners satisfied the autoclave and the ballistics resistant requirements of Military Specification MIL-L-41800, Liner , Soldier’s Steel Helmet, 1 May 1961.

Megagauss-level magnetic field production in cm-scale auto-magnetizing helical liners pulsed to 500 kA in 125 ns

DOE PAGES

Shipley, Gabriel A.; Awe, Thomas James; Hutsel, Brian Thomas; ...

2018-05-03

We present Auto-magnetizing (AutoMag) liners [Slutz et al., Phys. Plasmas 24, 012704 (2017)] are designed to generate up to 100 T of axial magnetic field in the fuel for Magnetized Liner Inertial Fusion [Slutz et al., Phys. Plasmas 17, 056303 (2010)] without the need for external field coils. AutoMag liners (cylindrical tubes) are composed of discrete metallic helical conduction paths separated by electrically insulating material. Initially, helical current in the AutoMag liner produces internal axial magnetic field during a long (100 to 300 ns) current prepulse with an average current rise rate dI/dt=5 kA/ns. After the cold fuel is magnetized,more » a rapidly rising current (200 kA/ns) generates a calculated electric field of 64 MV/m between the helices. Such field is sufficient to force dielectric breakdown of the insulating material after which liner current is reoriented from helical to predominantly axial which ceases the AutoMag axial magnetic field production mechanism and the z-pinch liner implodes. Proof of concept experiments have been executed on the Mykonos linear transformer driver to measure the axial field produced by a variety of AutoMag liners and to evaluate what physical processes drive dielectric breakdown. Lastly, a range of field strengths have been generated in various cm-scale liners in agreement with magnetic transient simulations including a measured field above 90 T at I = 350 kA. By varying the helical pitch angle, insulator material, and insulator geometry, favorable liner designs have been identified for which breakdown occurs under predictable and reproducible field conditions.« less

Megagauss-level magnetic field production in cm-scale auto-magnetizing helical liners pulsed to 500 kA in 125 ns

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

Shipley, Gabriel A.; Awe, Thomas James; Hutsel, Brian Thomas

We present Auto-magnetizing (AutoMag) liners [Slutz et al., Phys. Plasmas 24, 012704 (2017)] are designed to generate up to 100 T of axial magnetic field in the fuel for Magnetized Liner Inertial Fusion [Slutz et al., Phys. Plasmas 17, 056303 (2010)] without the need for external field coils. AutoMag liners (cylindrical tubes) are composed of discrete metallic helical conduction paths separated by electrically insulating material. Initially, helical current in the AutoMag liner produces internal axial magnetic field during a long (100 to 300 ns) current prepulse with an average current rise rate dI/dt=5 kA/ns. After the cold fuel is magnetized,more » a rapidly rising current (200 kA/ns) generates a calculated electric field of 64 MV/m between the helices. Such field is sufficient to force dielectric breakdown of the insulating material after which liner current is reoriented from helical to predominantly axial which ceases the AutoMag axial magnetic field production mechanism and the z-pinch liner implodes. Proof of concept experiments have been executed on the Mykonos linear transformer driver to measure the axial field produced by a variety of AutoMag liners and to evaluate what physical processes drive dielectric breakdown. Lastly, a range of field strengths have been generated in various cm-scale liners in agreement with magnetic transient simulations including a measured field above 90 T at I = 350 kA. By varying the helical pitch angle, insulator material, and insulator geometry, favorable liner designs have been identified for which breakdown occurs under predictable and reproducible field conditions.« less

Megagauss-level magnetic field production in cm-scale auto-magnetizing helical liners pulsed to 500 kA in 125 ns

NASA Astrophysics Data System (ADS)

Shipley, G. A.; Awe, T. J.; Hutsel, B. T.; Slutz, S. A.; Lamppa, D. C.; Greenly, J. B.; Hutchinson, T. M.

2018-05-01

Auto-magnetizing (AutoMag) liners [Slutz et al., Phys. Plasmas 24, 012704 (2017)] are designed to generate up to 100 T of axial magnetic field in the fuel for Magnetized Liner Inertial Fusion [Slutz et al., Phys. Plasmas 17, 056303 (2010)] without the need for external field coils. AutoMag liners (cylindrical tubes) are composed of discrete metallic helical conduction paths separated by electrically insulating material. Initially, helical current in the AutoMag liner produces internal axial magnetic field during a long (100 to 300 ns) current prepulse with an average current rise rate d I / d t = 5 k A / n s . After the cold fuel is magnetized, a rapidly rising current ( 200 k A / n s ) generates a calculated electric field of 64 M V / m between the helices. Such field is sufficient to force dielectric breakdown of the insulating material after which liner current is reoriented from helical to predominantly axial which ceases the AutoMag axial magnetic field production mechanism and the z-pinch liner implodes. Proof of concept experiments have been executed on the Mykonos linear transformer driver to measure the axial field produced by a variety of AutoMag liners and to evaluate what physical processes drive dielectric breakdown. A range of field strengths have been generated in various cm-scale liners in agreement with magnetic transient simulations including a measured field above 90 T at I = 350 kA. By varying the helical pitch angle, insulator material, and insulator geometry, favorable liner designs have been identified for which breakdown occurs under predictable and reproducible field conditions.

Liner for extrusion billet containers. Interim Technical Documentary Progress Report, February 1--April 30, 1963

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

Spachner, S. A.

1963-05-01

A shrink-fit assembly device for buildup of ceramiccoated liner and sleeve assemblies was tested and modified to develop desired temperatures and suitable heat distribution in sleeves, which were heated. Nine different compositions of fiber metal reinforced ceramic compacts were produced for preliminary evaluation of suitability for extrusion liner use. Procedures were developed for welding short, hollow ceramic cylinders of high-strength metal carbides and borides to form a ceramic extrusion liner of suitable length. Dissassembly tooling for rapid separation of shrink-fitted sleeves from a worn liner was designed, fabricated, and tested. Preliminary extrusion testing of an alumina-coated liner was carried out,more » using SAE 4340 steel billets extruded to rod at 12 : 1 and 16 : 1 ratios. No coating wear was noted after extrusion of 3 billets. (auth)« less

A finite element simulation of sound attenuation in a finite duct with a peripherally variable liner

NASA Technical Reports Server (NTRS)

Watson, W. R.

1977-01-01

Using multimodal analysis, a variational finite element method is presented for analyzing sound attenuation in a three-dimensional finite duct with a peripherally variable liner in the absence of flow. A rectangular element, with cubic shaped functions, is employed. Once a small portion of a peripheral liner is removed, the attenuation rate near the frequency where maximum attenuation occurs drops significantly. The positioning of the liner segments affects the attenuation characteristics of the liner. Effects of the duct termination are important in the low frequency ranges. The main effect of peripheral variation of the liner is a broadening of the attenuation characteristics in the midfrequency range. Because of matrix size limitations of the presently available computer program, the eigenvalue equations should be solved out of core in order to handle realistic sources.

Effect of Different Liners on Fracture Resistance of Premolars Restored with Conventional and Short Fiber-Reinforced Composite Resins.

PubMed

Shafiei, Fereshteh; Doozandeh, Maryam; Ghaffaripour, Dordaneh

2018-01-11

To see whether applying four different liners under short fiber-reinforced composite (SFRC), everX Posterior, compared to conventional composite resin, Z250, affected their strengthening property in premolar MOD cavities. Mesio-occluso-distal (MOD) cavities were prepared in 120 sound maxillary premolars divided into 10 groups (n = 12) in terms of two composite resin types and 4 liners or no liner. For each composite resin, in 5 groups no liner, resin-modified glass ionomer (RMGI), conventional flowable composite (COFL), self-adhesive flowable composite resin (SAFL), and self-adhesive resin cement (SARC) were applied prior to restoring incrementally. After water storage and thermocycling, static fracture resistance was tested. Data (in Newtons) were analyzed using two-way ANOVA (α = 0.05). Fracture resistance was significantly affected by composite resin type (p = 0.02), but not by the liner (p > 0.05). The interaction of the two factors was not statistically significant (p > 0.05). SFRC exhibited higher fracture strength (1470 ± 200 N) compared to conventional composite resin (1350 ± 290), irrespective of the application of liners. Application of SARC and SAFL liners led to a higher number of restorable fractures for both composite resins. The four liners can be used without interfering with the higher efficacy of SFRC, compared to conventional composite resins, to improve the fracture strength of premolar MOD cavities. © 2018 by the American College of Prosthodontists.

Development of Standardized Material Testing Protocols for Prosthetic Liners

PubMed Central

Cagle, John C.; Reinhall, Per G.; Hafner, Brian J.; Sanders, Joan E.

2017-01-01

A set of protocols was created to characterize prosthetic liners across six clinically relevant material properties. Properties included compressive elasticity, shear elasticity, tensile elasticity, volumetric elasticity, coefficient of friction (CoF), and thermal conductivity. Eighteen prosthetic liners representing the diverse range of commercial products were evaluated to create test procedures that maximized repeatability, minimized error, and provided clinically meaningful results. Shear and tensile elasticity test designs were augmented with finite element analysis (FEA) to optimize specimen geometries. Results showed that because of the wide range of available liner products, the compressive elasticity and tensile elasticity tests required two test maxima; samples were tested until they met either a strain-based or a stress-based maximum, whichever was reached first. The shear and tensile elasticity tests required that no cyclic conditioning be conducted because of limited endurance of the mounting adhesive with some liner materials. The coefficient of friction test was based on dynamic coefficient of friction, as it proved to be a more reliable measurement than static coefficient of friction. The volumetric elasticity test required that air be released beneath samples in the test chamber before testing. The thermal conductivity test best reflected the clinical environment when thermal grease was omitted and when liner samples were placed under pressure consistent with load bearing conditions. The developed procedures provide a standardized approach for evaluating liner products in the prosthetics industry. Test results can be used to improve clinical selection of liners for individual patients and guide development of new liner products. PMID:28233885

Inductively Driven, 3D Liner Compression of a Magnetized Plasma to Megabar Energy Densities

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

Slough, John

To take advantage of the smaller scale, higher density regime of fusion an efficient method for achieving the compressional heating required to reach fusion gain conditions must be found. What is proposed is a more flexible metallic liner compression scheme that minimizes the kinetic energy required to reach fusion. It is believed that it is possible to accomplish this at sub-megajoule energies. This however will require operation at very small scale. To have a realistic hope of inexpensive, repetitive operation, it is essential to have the liner kinetic energy under a megajoule which allows for the survivability of the vacuummore » and power systems. At small scale the implosion speed must be reasonably fast to maintain the magnetized plasma (FRC) equilibrium during compression. For limited liner kinetic energy, it becomes clear that the thinnest liner imploded to the smallest radius consistent with the requirements for FRC equilibrium lifetime is desired. The proposed work is directed toward accomplishing this goal. Typically an axial (Z) current is employed for liner compression. There are however several advantages to using a θ-pinch coil. With the θ-pinch the liner currents are inductively driven which greatly simplifies the apparatus and vacuum system, and avoids difficulties with the post implosion vacuum integrity. With fractional flux leakage, the foil liner automatically provides for the seed axial compression field. To achieve it with optimal switching techniques, and at an accelerated pace however will require additional funding. This extra expense is well justified as the compression technique that will be enabled by this funding is unique in the ability to implode individual segments of the liner at different times. This is highly advantageous as the liner can be imploded in a manner that maximizes the energy transfer to the FRC. Production of shaped liner implosions for additional axial compression can thus be readily accomplished with the modified power modules. The additional energy and switching capability proposed will thus provide for optimal utilization of the liner energy. The following tasks were outlined for the three year effort: (1) Design and assemble the foil liner compression test structure and chamber including the compression bank and test foils [Year 1]. (2) Perform foil liner compression experiments and obtain performance data over a range on liner dimensions and bank parameters [Year 2]. (3) Carry out compression experiments of the FRC plasma to Megagauss fields and measure key fusion parameters [Year 3]. (4) Develop numerical codes and analyze experimental results, and determine the physics and scaling for future work [Year 1-3]. The principle task of the project was to design and assemble the foil liner FRC formation chamber, the full compression test structure and chamber including the compression bank. This task was completed successfully. The second task was to test foils in the test facility constructed in year one and characterize the performance obtained from liner compression. These experimental measurements were then compared with analytical predictions, and numerical code results. The liner testing was completed and compared with both the analytical results as well as the code work performed with the 3D structural dynamics package of ANSYS Metaphysics®. This code is capable of modeling the dynamic behavior of materials well into the non-linear regime (e.g. a bullet hit plate glass). The liner dynamic behavior was found to be remarkably close to that predicted by the 3D structural dynamics results. Incorporating a code that can also include the magnetics and plasma physics has also made significant progress at the UW. The remaining test bed construction and assembly task is was completed, and the FRC formation and merging experiments were carried out as planned. The liner compression of the FRC to Megagauss fields was not performed due to not obtaining a sufficiently long lived FRC during the final year of the grant. Modifications planned to correct this deficiency included a larger FRC source as well as a much larger liner driver energy storage system. Due to discontinuation of the grant neither of these improvements were carried out.« less

An inventory of aeronautical ground research facilities. Volume 2: Air breathing engine test facilities

NASA Technical Reports Server (NTRS)

Pirrello, C. J.; Hardin, R. D.; Heckart, M. V.; Brown, K. R.

1971-01-01

The inventory covers free jet and direct connect altitude cells, sea level static thrust stands, sea level test cells with ram air, and propulsion wind tunnels. Free jet altitude cells and propulsion wind tunnels are used for evaluation of complete inlet-engine-exhaust nozzle propulsion systems under simulated flight conditions. These facilities are similar in principal of operation and differ primarily in test section concept. The propulsion wind tunnel provides a closed test section and restrains the flow around the test specimen while the free jet is allowed to expand freely. A chamber of large diameter about the free jet is provided in which desired operating pressure levels may be maintained. Sea level test cells with ram air provide controlled, conditioned air directly to the engine face for performance evaluation at low altitude flight conditions. Direct connect altitude cells provide a means of performance evaluation at simulated conditions of Mach number and altitude with air supplied to the flight altitude conditions. Sea level static thrust stands simply provide an instrumented engine mounting for measuring thrust at zero airspeed. While all of these facilities are used for integrated engine testing, a few provide engine component test capability.

Perforating devices for use in wells

DOEpatents

Jacoby, Jerome J.; Brooks, James E.; Aseltine, Clifford L.

2002-01-01

The perforating device for use in completing a well includes a case, an explosive charge contained in the case, and a generally bowl-shaped liner. The liner is positioned adjacent the explosive charge and has non-uniforrn thickness along its length. The liner further includes a protruding portion near its tip. In another configuration, the liner includes a hole near its tip to expose a portion of the explosive charge.

Shaped Charge Liner Materials: Resources, Processes, Properties, Costs, and Applications

DTIC Science & Technology

1991-02-01

SUBTITLE 5. FUNDING NUMBERS Shaped Charge Liner Materials: Resources, Processes, Properties, Costs, and Applications 2 6. AUTHOC Steven M. Buc 7...summaries of the mineral availability, Cq prmarymetal refinement processeb, material costs in raw form and as finished shaped charge liners , relevant... liner materials. 94-11479 gI 14, SUBJECT TERMS iSt NUMBER OF PAGIS 13chrg wrhad :xplosively formed penetrators material R. PRCE COEV" processing

Graphical Acoustic Liner Design and Analysis Tool

NASA Technical Reports Server (NTRS)

Howerton, Brian M. (Inventor); Jones, Michael G. (Inventor)

2016-01-01

An interactive liner design and impedance modeling tool comprises software utilized to design acoustic liners for use in constrained spaces, both regularly and irregularly shaped. A graphical user interface allows the acoustic channel geometry to be drawn in a liner volume while the surface impedance calculations are updated and displayed in real-time. A one-dimensional transmission line model may be used as the basis for the impedance calculations.

DoD Standard Design for Vertical ASTs

DTIC Science & Technology

2015-04-27

Roofs May-2012 33 56 13.15 Undertank Interstitial Space May-2012 33 56 63 Fuel Impermeable Liner System Apr-2006 32 13 15.20 Concrete Pavement ... Flexible Membrane Liner (FML) or  60 Mil HDPE Liner • NOT Concrete Surface • NOT Clay / Bentonite  Non-Woven Geotextile (Protective Layer...Required Flexible Membrane Liner 30  Non-Reinforced 60 mil High Density Polyethylene  Susceptible to Thermal Expansion and Degradation from

Skin-Inspired Hydrogel-Elastomer Composite with Application in a Moisture Permeable Prosthetic Limb Liner

NASA Astrophysics Data System (ADS)

Ruiz, Esteban

Recent advances in fields such as 3D printing, and biomaterials, have enabled the development of a moisture permeable prosthetic liner. This project demonstrates the feasibility of the invention by addressing the three primary areas of risk including the mechanical strength, the permeability, and the ability to manufacture. The key enabling technology which allows the liner to operate is the skin inspired hydrogel elastomer composite. The skin inspiration is reflected in the molecular arrangement of the double network of polymers which mimics collagen-elastin toughening in the natural epidermis. A custom formulation for a novel tough double network nanocomposite reinforced hydrogel was developed to improve manufacturability of the liner. The liner features this double network nanocomposite reinforced hydrogel as a permeable membrane which is reinforced on either side by perforated silicone layers manufactured by 3d printing assisted casting. Uniaxial compression tests were conducted on the individual hydrogels, as well as a representative sample of off the shelf prosthetic liners for comparison. Permeability testing was also done on the same set of materials and compared to literature values for traditional hydrogels. This work led to the manufacture of three generations of liner prototypes, with the second and third liner prototype being tested with human participants.

Thermographic inspection of pipes, tanks, and containment liners

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

Renshaw, Jeremy B., E-mail: jrenshaw@epri.com; Muthu, Nathan; Lhota, James R.

2015-03-31

Nuclear power plants are required to operate at a high level of safety. Recent industry and license renewal commitments aim to further increase safety by requiring the inspection of components that have not traditionally undergone detailed inspected in the past, such as tanks and liners. NEI 09-14 requires the inspection of buried pipes and tanks while containment liner inspections are required as a part of license renewal commitments. Containment liner inspections must inspect the carbon steel liner for defects - such as corrosion - that could threaten the pressure boundary and ideally, should be able to inspect the surrounding concretemore » for foreign material that could be in contact with the steel liner and potentially initiate corrosion. Such an inspection requires a simultaneous evaluation of two materials with very different material properties. Rapid, yet detailed, inspection results are required due to the massive size of the tanks and containment liners to be inspected. For this reason, thermal NDE methods were evaluated to inspect tank and containment liner mockups with simulated defects. Thermographic Signal Reconstruction (TSR) was utilized to enhance the images and provide detailed information on the sizes and shapes of the observed defects. The results show that thermographic inspection is highly sensitive to the defects of interest and is capable of rapidly inspecting large areas.« less

Backside Wear Analysis of Retrieved Acetabular Liners with a Press-Fit Locking Mechanism in Comparison to Wear Simulation In Vitro.

PubMed

Puente Reyna, Ana Laura; Jäger, Marcus; Floerkemeier, Thilo; Frecher, Sven; Delank, Karl-Stefan; Schilling, Christoph; Grupp, Thomas M

2016-01-01

Backside wear due to micromotion and poor conformity between the liner and its titanium alloy shell may contribute to the high rates of retroacetabular osteolysis and consequent aseptic loosening. The purpose of our study was to understand the wear process on the backside of polyethylene liners from two acetabular cup systems, whose locking mechanism is based on a press-fit cone in combination with a rough titanium conical inner surface on the fixation area. A direct comparison between in vitro wear simulator tests (equivalent to 3 years of use) and retrieved liners (average 13.1 months in situ) was done in order to evaluate the backside wear characteristics and behavior of these systems. Similar wear scores between in vitro tested and retrieved liners were observed. The results showed that this locking mechanism did not significantly produce wear marks at the backside of the polyethylene liners due to micromotion. In all the analyzed liners, the most common wear modes observed were small scratches at the cranial fixation zone directly below the rough titanium inner surface of the shell. It was concluded that most of the wear marks were produced during the insertion and removal of the liner, rather than during its time in situ.

One-dimensional MHD simulations of MTF systems with compact toroid targets and spherical liners

NASA Astrophysics Data System (ADS)

Khalzov, Ivan; Zindler, Ryan; Barsky, Sandra; Delage, Michael; Laberge, Michel

2017-10-01

One-dimensional (1D) MHD code is developed in General Fusion (GF) for coupled plasma-liner simulations in magnetized target fusion (MTF) systems. The main goal of these simulations is to search for optimal parameters of MTF reactor, in which spherical liquid metal liner compresses compact toroid plasma. The code uses Lagrangian description for both liner and plasma. The liner is represented as a set of spherical shells with fixed masses while plasma is discretized as a set of nested tori with circular cross sections and fixed number of particles between them. All physical fields are 1D functions of either spherical (liner) or small toroidal (plasma) radius. Motion of liner and plasma shells is calculated self-consistently based on applied forces and equations of state. Magnetic field is determined by 1D profiles of poloidal and toroidal fluxes - they are advected with shells and diffuse according to local resistivity, this also accounts for flux leakage into the liner. Different plasma transport models are implemented, this allows for comparison with ongoing GF experiments. Fusion power calculation is included into the code. We performed a series of parameter scans in order to establish the underlying dependencies of the MTF system and find the optimal reactor design point.

The Fusion Gain Analysis of the Inductively Driven Liner Compression Based Fusion

NASA Astrophysics Data System (ADS)

Shimazu, Akihisa; Slough, John

2016-10-01

An analytical analysis of the fusion gain expected in the inductively driven liner compression (IDLC) based fusion is conducted to identify the fusion gain scaling at various operating conditions. The fusion based on the IDLC is a magneto-inertial fusion concept, where a Field-Reversed Configuration (FRC) plasmoid is compressed via the inductively-driven metal liner to drive the FRC to fusion conditions. In the past, an approximate scaling law for the expected fusion gain for the IDLC based fusion was obtained under the key assumptions of (1) D-T fuel at 5-40 keV, (2) adiabatic scaling laws for the FRC dynamics, (3) FRC energy dominated by the pressure balance with the edge magnetic field at the peak compression, and (4) the liner dwell time being liner final diameter divided by the peak liner velocity. In this study, various assumptions made in the previous derivation is relaxed to study the change in the fusion gain scaling from the previous result of G ml1 / 2 El11 / 8 , where ml is the liner mass and El is the peak liner kinetic energy. The implication from the modified fusion gain scaling on the performance of the IDLC fusion reactor system is also explored.

Experimental Evaluation of Acoustic Engine Liner Models Developed with COMSOL Multiphysics

NASA Technical Reports Server (NTRS)

Schiller, Noah H.; Jones, Michael G.; Bertolucci, Brandon

2017-01-01

Accurate modeling tools are needed to design new engine liners capable of reducing aircraft noise. The purpose of this study is to determine if a commercially-available finite element package, COMSOL Multiphysics, can be used to accurately model a range of different acoustic engine liner designs, and in the process, collect and document a benchmark dataset that can be used in both current and future code evaluation activities. To achieve these goals, a variety of liner samples, ranging from conventional perforate-over-honeycomb to extended-reaction designs, were installed in one wall of the grazing flow impedance tube at the NASA Langley Research Center. The liners were exposed to high sound pressure levels and grazing flow, and the effect of the liner on the sound field in the flow duct was measured. These measurements were then compared with predictions. While this report only includes comparisons for a subset of the configurations, the full database of all measurements and predictions is available in electronic format upon request. The results demonstrate that both conventional perforate-over-honeycomb and extended-reaction liners can be accurately modeled using COMSOL. Therefore, this modeling tool can be used with confidence to supplement the current suite of acoustic propagation codes, and ultimately develop new acoustic engine liners designed to reduce aircraft noise.

Thermographic inspection of pipes, tanks, and containment liners

NASA Astrophysics Data System (ADS)

Renshaw, Jeremy B.; Lhota, James R.; Muthu, Nathan; Shepard, Steven M.

2015-03-01

Nuclear power plants are required to operate at a high level of safety. Recent industry and license renewal commitments aim to further increase safety by requiring the inspection of components that have not traditionally undergone detailed inspected in the past, such as tanks and liners. NEI 09-14 requires the inspection of buried pipes and tanks while containment liner inspections are required as a part of license renewal commitments. Containment liner inspections must inspect the carbon steel liner for defects - such as corrosion - that could threaten the pressure boundary and ideally, should be able to inspect the surrounding concrete for foreign material that could be in contact with the steel liner and potentially initiate corrosion. Such an inspection requires a simultaneous evaluation of two materials with very different material properties. Rapid, yet detailed, inspection results are required due to the massive size of the tanks and containment liners to be inspected. For this reason, thermal NDE methods were evaluated to inspect tank and containment liner mockups with simulated defects. Thermographic Signal Reconstruction (TSR) was utilized to enhance the images and provide detailed information on the sizes and shapes of the observed defects. The results show that thermographic inspection is highly sensitive to the defects of interest and is capable of rapidly inspecting large areas.

Numerical Investigation of the Acoustic Damping of Plane Acoustic Waves by Perforated Liners with Bias Flow

NASA Astrophysics Data System (ADS)

Zhao, Dan; Zhong, Zhi Yuan

Perforated liners are extensively used in aero-engines and gas turbine combustors to suppress combustion instabilities. These liners, typically subjected to a low Mach number bias flow (a cooling flow through perforated holes), are fitted along the bounding walls of a combustor to convert acoustic energy into flow energy by generating vorticity at the rims of the perforated apertures. To investigate the acoustic damping of such liners with bias flow on plane acoustic waves, a time-domain numerical model is developed to compute acoustic wave propagation in a cylindrical duct with a single-layer liner attached. The damping mechanism of the liner is characterized in real-time by using a 'compliance', developed especially for this work. It is a rational function representation of the frequency-domain homogeneous compliance adapted from the Rayleigh conductivity of a single aperture with mean bias flow in the z-domain. The liner 'compliance' model is then incorporated into partial differential equations of the duct system, which are solved by using the method of lines. The numerical results are then evaluated by comparing with the numerical results of Eldredge and Dowling's frequency-domain model. Good agreement is observed. This confirms that the model and the approach developed are suitable for real-time characterizing the acoustic damping of perforated liners.

Construction and performance of a long-term earthen liner experiment

USGS Publications Warehouse

Cartwright, Keros; Krapac, Ivan G.; Bonaparte, Rudolph

1990-01-01

In land burial schemes, compacted soil barriers with low hydraulic conductivity are commonly used in cover and liner systems to control the movement of liquids and prevent groundwater contamination. An experimental liner measuring 8 x 15 x 0.9 m was constructed with design criteria and equipment to simulate construction of soil liners built at waste disposal facilities. The surface of the liner was flooded with a 29.5 cm deep pond on April 12, 1988. Infiltration of water into the liner has been monitored for two years using 4 large-ring (1.5 m OD) and 32 small-ring (0.28 m OD) infiltrometers, and a water-balance that accounts for total infiltration and evaporation. Average long-term infiltration fluxes based on two years of monitoring are 5.8 x 10-9 cm/s, 6.0 x 10-8 cm/s and 5.6 x 10-8 for the large-ring, small-ring, and water-balance data, respectively. The saturated hydraulic conductivity of the liner based on small-ring data, estimated using Darcy's Law and the Green-Ampt Approximation, is 3 x 10-8 and 4 x 10-8 cm/s, respectively. All sets of data indicate that the liner's performance exceed that which is required by the U.S. EPA.

Liner mounting assembly

NASA Technical Reports Server (NTRS)

Halila, Ely E. (Inventor)

1994-01-01

A mounting assembly includes an annular supporting flange disposed coaxially about a centerline axis which has a plurality of circumferentially spaced apart supporting holes therethrough. An annular liner is disposed coaxially with the supporting flange and includes a plurality of circumferentially spaced apart mounting holes aligned with respective ones of the supporting holes. Each of a plurality of mounting pins includes a proximal end fixedly joined to the supporting flange through a respective one of the supporting holes, and a distal end disposed through a respective one of the liner mounting holes for supporting the liner to the supporting flange while unrestrained differential thermal movement of the liner relative to the supporting flange.

Testing and Characterization of CMC Combustor Liners

NASA Technical Reports Server (NTRS)

Robinson, R. Craig; Verrilli, Michael J.

2003-01-01

Multiple combustor liner applications, both segmented and fully annular designs, have been configured for exposure in NASA's High Pressure Burner Rig (HPBR). The segmented liners were attached to the rig structure with SiC/SiC fasteners and exposed to simulated gas turbine conditions for nearly 200 hours. Test conditions included pressures of 6 atm., gas velocity of 42 m/s, and gas temperatures near 1450 C. The temperatures of both the cooled and combustion flow sides of the liners were measured using optical and contact measurement techniques. Minor weight loss was observed, but the liners remained structural sound, although damage was noted in some fasteners.

Ceramic coating effect on liner metal temperatures of film-cooled annular combustor

NASA Technical Reports Server (NTRS)

Claus, R. W.; Wear, J. D.; Liebert, C. H.

1979-01-01

An experimental and analytical investigation was conducted to determine the effect of a ceramic coating on the average metal temperatures of full annular, film cooled combustion chamber liner. The investigation was conducted at pressures from 0.50 to 0.062. At all test conditions, experimental results indicate that application of a ceramic coating will result in significantly lower wall temperatures. In a simplified heat transfer analysis, agreement between experimental and calculated liner temperatures was achieved. Simulated spalling of a small portion of the ceramic coating resulted in only small increases in liner temperature because of the thermal conduction of heat from the hotter, uncoated liner metal.

Aerogel Use as a Skin Protective Liner In Space Suits and Prosthetic Limbs Project

NASA Technical Reports Server (NTRS)

Roberson, Luke Bennett

2014-01-01

Existing materials for prosthetic liners tend to be thick and airtight, causing perspiration to accumulate inside the liner and potentially causing infection and injury. The purpose of this project was to examine the suitability of aerogel for prosthetic liner applications for use in space suits and orthopedics. Three tests were performed on several types of aerogel to assess the properties of each material, and our initial findings demonstrated that these materrials would be excellent candidates for liner applications for prosthetics and space suits. The project is currently on hold until additional funding is obtained for application testing at the VH Hospitals in Tampa

Surface treatment using metal foil liner

NASA Technical Reports Server (NTRS)

Garvey, Ray

1989-01-01

A metal foil liner can be used to seal large area surfaces. Characteristics of the two-layer foil liner are discussed. Micrographs for foil-to-foil, foil-to-composite, visible seams, and hidden seams are examined.

LEO-to-GEO low thrust chemical propulsion

NASA Technical Reports Server (NTRS)

Shoji, J. M.

1980-01-01

One approach being considered for transporting large space structures from low Earth orbit (LEO) to geosynchronous equatorial orbit (GEO) is the use of low thrust chemical propulsion systems. A variety of chemical rocket engine cycles evaluated for this application for oxygen/hydrogen and oxygen/hydrocarbon propellants (oxygen/methane and oxygen/RF-1) are discussed. These cycles include conventional propellant turbine drives, turboalternator/electric motor pump drive, and fuel cell/electric motor pump drive as well as pressure fed engines. Thrust chamber cooling analysis results are presented for regenerative/radiation and film/radiation cooling.

Shock Mounting for Heavy Machines

NASA Technical Reports Server (NTRS)

Thompson, A. R.

1984-01-01

Elastomeric bearings eliminate extraneous forces. Rocket thrust transmitted from motor to load cells via support that absorbs extraneous forces so they do not affect accuracy of thrust measurements. Adapter spoked cone fits over forward end of rocket motor. Shock mounting developed for rocket engines under test used as support for heavy machines, bridges, or towers.

Computer method for design of acoustic liners for turbofan engines

NASA Technical Reports Server (NTRS)

Minner, G. L.; Rice, E. J.

1976-01-01

A design package is presented for the specification of acoustic liners for turbofans. An estimate of the noise generation was made based on modifications of existing noise correlations, for which the inputs are basic fan aerodynamic design variables. The method does not predict multiple pure tones. A target attenuation spectrum was calculated which was the difference between the estimated generation spectrum and a flat annoyance-weighted goal attenuated spectrum. The target spectrum was combined with a knowledge of acoustic liner performance as a function of the liner design variables to specify the acoustic design. The liner design method at present is limited to annular duct configurations. The detailed structure of the liner was specified by combining the required impedance (which is a result of the previous step) with a mathematical model relating impedance to the detailed structure. The design procedure was developed for a liner constructed of perforated sheet placed over honeycomb backing cavities. A sample calculation was carried through in order to demonstrate the design procedure, and experimental results presented show good agreement with the calculated results of the method.

A systematic review of the effect of daily panty liner use on the vulvovaginal environment.

PubMed

Pontes, Ana C; Amaral, Rose L G; Giraldo, Paulo C; Beghini, Joziani; Giraldo, Helena P D; Cordeiro, Etienne S

2014-10-01

Whether panty liners predispose to vulvovaginitis is unclear. To clarify the effects of the use of panty liners on the female genital tract. Several electronic databases (including PubMed and Embase) were searched to identify studies published in English before May 3, 2012. Case-control studies, randomized controlled trials, and cohort studies comparing young women who did and did not use panty liners in the intermenstrual period were included. The quality of the studies was assessed using the Newcastle-Ottawa Scale or the Jadad Scale. Data from suitable studies were extracted for analysis. Five articles met the inclusion criteria. Four studies-all of which included only healthy women-found no significant clinical implications arising from the use of panty liners. The fifth study was of women with recurrent candidiasis and showed that use of panty liners was associated with new candidiasis episodes. The intermenstrual use of panty liners does not seem to have a negative effect on the vulvovaginal area. Copyright © 2014 International Federation of Gynecology and Obstetrics. Published by Elsevier Ireland Ltd. All rights reserved.

Hazardous waste treatment for spent pot liner

NASA Astrophysics Data System (ADS)

Zhao, Xia; Ma, Lei

2018-01-01

The spent pot liner is the largest solid waste produced by the electrolytic aluminum industry, composed of a series of substances that accumulate in the containers with reduced aluminum during the process of bauxite purification and refining. More and more spent pot liner is accumulated and needs to be dealt with. This paper discusses the composition and harm of solid waste. This paper expounds the comprehensive utilization value and disposition of the waste pot liner.

Duct Liner Optimization for Turbomachinery Noise Sources

DTIC Science & Technology

1975-11-01

AD-A279 441lIIIflhIh* NASA TECHNICAL NASA TMA X-72789 MEMORANDUM oo £ 00 r-:. DUCT LINER OPTIMIZATION FOR TURBOMACHINERY w NOISE SOURCES By Harold C...Recipient’s r.atalog No. NASA TM X-72789! 4 Title diid Subtitle 5. Rewrt Date Duct Liner Optimization for Turbomachinery Noise Sources November 1975...profiles is combined wit., a numerical minimization algorithm to predict optimal liner configurations having one, two, and three sections. Source models

Evaluating the accuracy of wear formulae for acetabular cup liners.

PubMed

Wu, James Shih-Shyn; Hsu, Shu-Ling; Chen, Jian-Horng

2010-02-01

This study proposes two methods for exploring the wear volume of a worn liner. The first method is a numerical method, in which SolidWorks software is used to create models of the worn out regions of liners at various wear directions and depths. The second method is an experimental one, in which a machining center is used to mill polyoxymethylene to manufacture worn and unworn liner models, then the volumes of the models are measured. The results show that the SolidWorks software is a good tool for presenting the wear pattern and volume of a worn liner. The formula provided by Ilchmann is the most suitable for computing liner volume loss, but is not accurate enough. This study suggests that a more accurate wear formula is required. This is crucial for accurate evaluation of the performance of hip components implanted in patients, as well as for designing new hip components.

Stabilized Liner Compressor: The Return of Linus

NASA Astrophysics Data System (ADS)

Turchi, Peter; Frese, Sherry; Frese, Michael; Mielke, Charles; Hinrichs, Mark; Nguyen, Doan

2015-11-01

To access the lower cost regime of magneto-inertial fusion at megagauss magnetic field-levels requires the use of dynamic conductors in the form of imploding cylindrical shells, aka, liners. Such liner implosions can compress magnetic flux and plasma to attain fusion conditions, but are subject to Rayleigh-Taylor instabilities, both in the launch and recovery of the liner material and in the final few diameters of implosion. These instabilities were overcome in the Linus program at the Naval Research Laboratory, c. 1979, providing the experimentally-demonstrated basis for repetitive operation and leading to an economical reactor concept at low fusion gain. The recent ARPA-E program for low-cost fusion technology has revived interest in this approach. We shall discuss progress in modeling and design of a Stabilized Liner Compressor (SLC) that extends the earlier work to higher pressures and liner speeds appropriate to potential plasma targets. Sponsored by ARPA-E ALPHA Program.

Modeling the interactions between a prosthetic socket, polyurethane liners and the residual limb in transtibial amputees using non-linear finite element analysis.

PubMed

Simpson, G; Fisher, C; Wright, D K

2001-01-01

Continuing earlier studies into the relationship between the residual limb, liner and socket in transtibial amputees, we describe a geometrically accurate non-linear model simulating the donning of a liner and then a socket. The socket is rigid and rectified and the liner is a polyurethane geltype which is accurately described using non-linear (Mooney-Rivlin) material properties. The soft tissue of the residual limb is modelled as homogeneous, non-linear and hyperelastic and the bone structure within the residual limb is taken as rigid. The work gives an indication of how the stress induced by the process of donning the rigid socket is redistributed by the liner. Ultimately we hope to understand how the liner design might be modified to reduce discomfort. The ANSYS finite element code, version 5.6 is used.

Technique for fabrication of ultrathin foils in cylindrical geometry for liner-plasma implosion experiments with sub-megaampere currents

DOE PAGES

Yager-Elorriaga, D. A.; Steiner, A. M.; Patel, S. G.; ...

2015-11-19

In this study, we describe a technique for fabricating ultrathin foils in cylindrical geometry for liner-plasma implosion experiments using sub-MA currents. Liners are formed by wrapping a 400 nm, rectangular strip of aluminum foil around a dumbbell-shaped support structure with a non-conducting center rod, so that the liner dimensions are 1 cm in height, 6.55 mm in diameter, and 400 nm in thickness. The liner-plasmas are imploded by discharging ~600 kA with ~200 ns rise time using a 1 MA linear transformer driver, and the resulting implosions are imaged four times per shot using laser-shadowgraphy at 532 nm. As amore » result, this technique enables the study of plasma implosion physics, including the magneto Rayleigh-Taylor, sausage, and kink instabilities on initially solid, imploding metallic liners with university-scale pulsed power machines.« less

Technique for fabrication of ultrathin foils in cylindrical geometry for liner-plasma implosion experiments with sub-megaampere currents

NASA Astrophysics Data System (ADS)

Yager-Elorriaga, D. A.; Steiner, A. M.; Patel, S. G.; Jordan, N. M.; Lau, Y. Y.; Gilgenbach, R. M.

2015-11-01

In this work, we describe a technique for fabricating ultrathin foils in cylindrical geometry for liner-plasma implosion experiments using sub-MA currents. Liners are formed by wrapping a 400 nm, rectangular strip of aluminum foil around a dumbbell-shaped support structure with a non-conducting center rod, so that the liner dimensions are 1 cm in height, 6.55 mm in diameter, and 400 nm in thickness. The liner-plasmas are imploded by discharging ˜600 kA with ˜200 ns rise time using a 1 MA linear transformer driver, and the resulting implosions are imaged four times per shot using laser-shadowgraphy at 532 nm. This technique enables the study of plasma implosion physics, including the magneto Rayleigh-Taylor, sausage, and kink instabilities on initially solid, imploding metallic liners with university-scale pulsed power machines.

Fractures of a single design of highly cross-linked polyethylene acetabular liners: an analysis of voluntary reports to the United States Food and Drug Administration.

PubMed

Ast, Michael P; John, Thomas K; Labbisiere, Anthony; Robador, Nicolas; Valle, Alejandro Gonzalez Della

2014-06-01

Polyethylene liner fracture is a risk associated with the use of highly cross-linked UHMWPE. We performed a review of the voluntary reports of fractured liners to the US Food and Drug Administration to determine if any risk factors could be identified. There have been 74 reports of fractured Trilogy, Longevity liners to the US Food and Drug Administration since 1999. Most cases utilized small acetabular shells (≤54 mm) combined with large diameter heads (≥36 mm). Liners less than 7 mm thick at the weight bearing or 4.8 mm thick at the rim should be used with caution. At revision surgery, malpositioned shells should be revised and the use of a thin liner should be avoided. Copyright © 2014 Elsevier Inc. All rights reserved.

Technique for fabrication of ultrathin foils in cylindrical geometry for liner-plasma implosion experiments with sub-megaampere currents

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

Yager-Elorriaga, D. A.; Steiner, A. M.; Patel, S. G.

In this study, we describe a technique for fabricating ultrathin foils in cylindrical geometry for liner-plasma implosion experiments using sub-MA currents. Liners are formed by wrapping a 400 nm, rectangular strip of aluminum foil around a dumbbell-shaped support structure with a non-conducting center rod, so that the liner dimensions are 1 cm in height, 6.55 mm in diameter, and 400 nm in thickness. The liner-plasmas are imploded by discharging ~600 kA with ~200 ns rise time using a 1 MA linear transformer driver, and the resulting implosions are imaged four times per shot using laser-shadowgraphy at 532 nm. As amore » result, this technique enables the study of plasma implosion physics, including the magneto Rayleigh-Taylor, sausage, and kink instabilities on initially solid, imploding metallic liners with university-scale pulsed power machines.« less

Staged Z-pinch for the production of high-flux neutrons and net energy

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

Wessel, Frank J.; Rahman, Hafiz Ur; Rostoker, Norman

A fusible target is embedded in a high Z liner, ohmically heated and then shock wave heated by implosion of an enveloping high Z liner. The target is adiabatically heated by compression, fusibly ignited and charged-particle heated as it is being ignited. A shock front forms as the liner implodes which shock front detaches from the more slowly moving liner, collides with the outer surface of the target, accelerates inward, rapidly heating the target, adiabatically compressing the target and liner and amplifying the current to converge the liner mass toward a central axis thereby compressing the target to a fusionmore » condition when it begins to ignite and produce charged particles. The charged particles are trapped in a large magnetic field surrounding the target. The energy of the charged particles is deposited into the target to further heat the target to produce an energy gain.« less

The photoionization mechanism of LINERs - Stellar and nonstellar

NASA Technical Reports Server (NTRS)

Ho, Luis C.; Filippenko, Alexei V.

1993-01-01

We present high quality spectroscopic observations of a sample of 14 LINERs. Starlight removal is achieved by the subtraction of a suitable absorption-line 'template' galaxy, allowing accurate measurements of emission lines. We use these line fluxes to examine the possible excitation mechanisms of LINERs. We suggest that LINERs with weak forbidden O I 6300-A emission may be H II regions photoionized by unusually hot O-type stars. LINERs with forbidden O I/H-alpha approximately greater than 1/6 may be powered by photoionization from a nonstellar continuum. This is supported by the detection of broad H-alpha emission, a correlation between line width and critical density, and pointlike X-ray emission in several of these objects.

Experimental demonstration of the stabilizing effect of dielectric coatings on magnetically accelerated imploding metallic liners

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

Awe, Thomas James; Peterson, Kyle J.; Yu, Edmund P.

Enhanced implosion stability has been experimentally demonstrated for magnetically accelerated liners that are coated with 70 μm of dielectric. The dielectric tamps liner-mass redistribution from electrothermal instabilities and also buffers coupling of the drive magnetic field to the magneto-Rayleigh-Taylor instability. A dielectric-coated and axially premagnetized beryllium liner was radiographed at a convergence ratio [CR=R in,0/R in(z,t)] of 20, which is the highest CR ever directly observed for a strengthless magnetically driven liner. Lastly, the inner-wall radius R in(z,t) displayed unprecedented uniformity, varying from 95 to 130 μm over the 4.0 mm axial height captured by the radiograph.

Experimental demonstration of the stabilizing effect of dielectric coatings on magnetically accelerated imploding metallic liners

DOE PAGES

Awe, Thomas James; Peterson, Kyle J.; Yu, Edmund P.; ...

2016-02-10

Enhanced implosion stability has been experimentally demonstrated for magnetically accelerated liners that are coated with 70 μm of dielectric. The dielectric tamps liner-mass redistribution from electrothermal instabilities and also buffers coupling of the drive magnetic field to the magneto-Rayleigh-Taylor instability. A dielectric-coated and axially premagnetized beryllium liner was radiographed at a convergence ratio [CR=R in,0/R in(z,t)] of 20, which is the highest CR ever directly observed for a strengthless magnetically driven liner. Lastly, the inner-wall radius R in(z,t) displayed unprecedented uniformity, varying from 95 to 130 μm over the 4.0 mm axial height captured by the radiograph.

Experimental Impedance of Single Liner Elements with Bias Flow

NASA Technical Reports Server (NTRS)

Follet, J. I.; Betts, J. F.; Kelly, Jeffrey J.; Thomas, Russell H.

2000-01-01

An experimental investigation was conducted to generate a high quality database, from which the effects of a mean bias flow on the acoustic impedance of lumped-element single-degree-of-freedom liners was determined. Acoustic impedance measurements were made using the standard two-microphone method in the NASA Langley Normal Incidence Tube. Each liner consisted of a perforated sheet with a constant-area cavity. Liner resistance was shown to increase and to become less frequency and sound pressure level dependent as the bias flow was increased. The resistance was also consistently lower for a negative bias flow (suction) than for a positive bias flow (blowing) of equal magnitude. The slope of the liner reactance decreased with increased flow.

Numerical study on non-locally reacting behavior of nacelle liners incorporating drainage slots

NASA Astrophysics Data System (ADS)

Chen, Chao; Li, Xiaodong; Thiele, Frank

2018-06-01

For acoustic liners used in current commercial nacelles, in order to prevent any liquid accumulating in the resonators, drainage slots are incorporated on the partition walls between closely packed cavities. Recently, an experimental study conducted by Busse-Gerstengarbe et al. shown that the cell interaction introduced by drainage slots causes an additional dissipation peak which increases with the size of the slot. However, the variation of damping process due to drainage slots is still not fully understood. Therefore, a numerical study based on computational aeroacoustic methods is carried out to investigate the mechanism of the changed attenuation characteristics due to drainage slots in presence of grazing incident sound waves with low or high intensities. Different slot configurations are designed based on the generic non-locally reacting liner model adopted in the experimental investigation. Both 2-D and 3-D numerical simulations of only slit resonators are carried out. Numerical results indicate that the extra peak is a result of a resonance excited in the second cavity at specific frequency. Under high sound pressure level incoming waves, the basic characteristics of the acoustic performance remain. However, vortex shedding transpires at the resonances around both the slits and the drainage slot. Vorticity contours show that the connection of two coupled cavities decreases the strength of vortex shedding around the basic Helmholtz resonance due to a higher energy reflection. Meanwhile, the cell interaction significantly increases the vorticity magnitude near the extra resonant frequency. Finally, a semi-empirical model is derived to predict the extra attenuation peak frequency.

Comparative evaluation of tensile bond strength of a polyvinyl acetate-based resilient liner following various denture base surface pre-treatment methods and immersion in artificial salivary medium: An in vitro study.

PubMed

Philip, Jacob M; Ganapathy, Dhanraj M; Ariga, Padma

2012-07-01

This study was formulated to evaluate and estimate the influence of various denture base resin surface pre-treatments (chemical and mechanical and combinations) upon tensile bond strength between a poly vinyl acetate-based denture liner and a denture base resin. A universal testing machine was used for determining the bond strength of the liner to surface pre-treated acrylic resin blocks. The data was analyzed by one-way analysis of variance and the t-test (α =.05). This study infers that denture base surface pre-treatment can improve the adhesive tensile bond strength between the liner and denture base specimens. The results of this study infer that chemical, mechanical, and mechano-chemical pre-treatments will have different effects on the bond strength of the acrylic soft resilient liner to the denture base. Among the various methods of pre-treatment of denture base resins, it was inferred that the mechano-chemical pre-treatment method with air-borne particle abrasion followed by monomer application exhibited superior bond strength than other methods with the resilient liner. Hence, this method could be effectively used to improve bond strength between liner and denture base and thus could minimize delamination of liner from the denture base during function.

A Finite Element Theory for Predicting the Attenuation of Extended-Reacting Liners

NASA Technical Reports Server (NTRS)

Watson, W. R.; Jones, M. G.

2009-01-01

A non-modal finite element theory for predicting the attenuation of an extended-reacting liner containing a porous facesheet and located in a no-flow duct is presented. The mathematical approach is to solve separate wave equations in the liner and duct airway and to couple these two solutions by invoking kinematic constraints at the facesheet that are consistent with a continuum theory of fluid motion. Given the liner intrinsic properties, a weak Galerkin finite element formulation with cubic polynomial basis functions is used as the basis for generating a discrete system of acoustic equations that are solved to obtain the coupled acoustic field. A state-of-the-art, asymmetric, parallel, sparse equation solver is implemented that allows tens of thousands of grid points to be analyzed. A grid refinement study is presented to show that the predicted attenuation converges. Excellent comparison of the numerically predicted attenuation to that of a mode theory (using a Haynes 25 metal foam liner) is used to validate the computational approach. Simulations are also presented for fifteen porous plate, extended-reacting liners. The construction of some of the porous plate liners suggest that they should behave as resonant liners while the construction of others suggest that they should behave as broadband attenuators. In each case the finite element theory is observed to predict the proper attenuation trend.

LINER galaxy properties and the local environment

NASA Astrophysics Data System (ADS)

Coldwell, Georgina V.; Alonso, Sol; Duplancic, Fernanda; Mesa, Valeria

2018-05-01

We analyse the properties of a sample of 5560 low-ionization nuclear emission-line region (LINER) galaxies selected from SDSS-DR12 at low red shift, for a complete range of local density environments. The host LINER galaxies were studied and compared with a well-defined control sample of 5553 non-LINER galaxies matched in red shift, luminosity, morphology and local density. By studying the distributions of galaxy colours and the stellar age population, we find that LINERs are redder and older than the control sample over a wide range of densities. In addition, LINERs are older than the control sample, at a given galaxy colour, indicating that some external process could have accelerated the evolution of the stellar population. The analysis of the host properties shows that the control sample exhibits a strong relation between colours, ages and the local density, while more than 90 per cent of the LINERs are redder and older than the mean values, independently of the neighbourhood density. Furthermore, a detailed study in three local density ranges shows that, while control sample galaxies are redder and older as a function of stellar mass and density, LINER galaxies mismatch the known morphology-density relation of galaxies without low-ionization features. The results support the contribution of hot and old stars to the low-ionization emission although the contribution of nuclear activity is not discarded.

ELECTRICAL RESISTIVITY TECHNIQUE TO ASSESS THE INTEGRITY OF GEOMEMBRANE LINERS

EPA Science Inventory

Two-dimensional electrical modeling of a liner system was performed using computer techniques. The modeling effort examined the voltage distributions in cross sections of lined facilities with different leak locations. Results confirmed that leaks in the liner influenced voltage ...

Formed platelet combustor liner construction feasibility, phase A

NASA Technical Reports Server (NTRS)

Hayes, W. A.; Janke, D. E.

1992-01-01

Environments generated in high pressure liquid rocket engines impose severe requirements on regeneratively cooled combustor liners. Liners fabricated for use in high chamber pressures using conventional processes suffer from limitations that can impair operational cycle life and can adversely affect wall compatibility. Chamber liners fabricated using formed platelet technology provide an alternative to conventional regeneratively cooled liners (an alternative that has many attractive benefits). A formed platelet liner is made from a stacked assembly of platelets with channel features. The assembly is diffusion bonded into a flat panel and then three-dimensionally formed into a section of a chamber. Platelet technology permits the liner to have very precisely controlled and thin hot gas walls and therefore increased heat transfer efficiency. Further cooling efficiencies can be obtained through enhanced design flexibility. These advantages translate into increased cycle life and enhanced wall compatibility. The increased heat transfer efficiency can alternately be used to increase engine performance or turbopump life as a result of pressure drop reductions within the regeneratively cooled liner. Other benefits can be obtained by varying the materials of construction within the platelet liner to enhance material compatibility with operating environment or with adjoining components. Manufacturing cost savings are an additional benefit of a formed platelet liner. This is because of reduced touch labor and reduced schedule when compared to conventional methods of manufacture. The formed platelet technology is not only compatible with current state-of-the art combustion chamber structural support and manifolding schemes, it is also an enabling technology that allows the use of other high performance and potentially low cost methods of construction for the entire combustion chamber assembly. The contract under which this report is submitted contains three phases: (1) phase A - feasibility study and technology development; (2) phase B - sub-scale fabrication feasibility; and (3) phase C - large scale fabrication validation. This report covers the Phase A activities, which began in December of 1988.

ACOUSTIC LINERS FOR TURBOFAN ENGINES

NASA Technical Reports Server (NTRS)

Minner, G. L.

1994-01-01

This program was developed to design acoustic liners for turbofan engines. This program combines results from theoretical models of wave alternation in acoustically treated passages with experimental data from full-scale fan noise suppressors. By including experimentally obtained information, the program accounts for real effects such as wall boundary layers, duct terminations, and sound modal structure. The program has its greatest use in generating a number of design specifications to be used for evaluation of trade-offs. The program combines theoretical and empirical data in designing annular acoustic liners. First an estimate of the noise output of the fan is made based on basic fan aerodynamic design variables. Then, using a target noise spectrum after alternation and the estimated fan noise spectrum, a design spectrum is calculated as their difference. Next, the design spectrum is combined with knowledge of acoustic liner performance and the liner design variables to specify the acoustic design. Details of the liner design are calculated by combining the required acoustic impedance with a mathematical model relating acoustic impedance to the physical structure of the liner. Input to the noise prediction part of the program consists of basic fan operating parameters, distance that the target spectrum is to be measured and the target spectrum. The liner design portion of the program requires the required alternation spectrum, desired values of length to height and several option selection parameters. Output from the noise prediction portion is a noise spectrum consisting of discrete tones and broadband noise. This may be used as input to the liner design portion of the program. The liner design portion of the program produces backing depths, open area ratios, and face plate thicknesses. This program is written in FORTRAN V and has been implemented in batch mode on a UNIVAC 1100 series computer with a central memory requirement of 12K (decimal) of 36 bit words.

Development of a combustor liner composed of ceramic matrix composite (CMC)

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

Nishio, K.; Igashira, K.I.; Take, K.

The Research Institute of Advanced Materials Gas-Generator (AMG), which is a joint effort by the Japan Key Technology Center and 14 firms in Japan, has, since fiscal year 1992, been conducting technological studies on an innovative gas generator that will use 20% less fuel, weight 50% less, and emit 70% less NO{sub x} than the conventional gas generator through the use of advanced materials. Within this project, there is an R and D program for applying ceramic matrix composite (CMC) liners to the combustor, which is a major component of the gas generator. In the course of R and D,more » continuous SiC fiber-reinforced SiC composite (SiC{sup F}/SiC) was selected as the most suitable CMD for the combustor liner because of its thermal stability and formability. An evaluation of the applicability of the SiC{sup F}/SiC composite to the combustor liner on the basis of an evaluation of its mechanical properties and stress analysis of a SiC{sup F}/SiC combustor liner was carried out, and trial SiC{sup F}/SiC combustor liners, the largest of which was 500-mm in diameter, were fabricated by the filament winding and PIP (polymer impregnation and pyrolysis) method. Using a SiC{sup F}/SiC liner built to the actual dimensions, a noncooling combustion test was carried out and even when the gas temperature was raised to 1873K at outlet of the liner, no damage was observed after the test. Through their studies, the authors have confirmed the applicability of the selected SiC{sup F}/SiC composite as a combustor liner. In this paper, the authors describe the present state of the R and D of a CMC combustor liner.« less

The PLX- α Project: Progress and Plans

NASA Astrophysics Data System (ADS)

Hsu, S.; Witherspoon, F. D.; Cassibry, J.; Gilmore, M.; Samulyak, R.; Stoltz, P.; PLX-α Team

2016-10-01

The Plasma Liner Experiment-ALPHA (PLX- α) project aims to demonstrate the viability of spherically imploding plasma liners as a standoff driver for plasma-jet-driven magneto-inertial fusion (PJMIF). In the past year, progress has been made in designing and testing new contoured-gap coaxial guns, 3D model development and simulations (via Eulerian and Lagrangian hydrocodes) of PLX- α-relevant plasma-liner formation/implosion via up to 60 plasma jets ( 100 kJ of liner kinetic energy), 1D semi-analytic and numerical modeling of reactor-scale PJMIF (10s of MJ of liner kinetic energy), and preparation/upgrade of the PLX facility/diagnostics. The design goal for the coaxial guns is to form plasma jets of up to initial n 2 ×1016 cm-3, mass 5 mg, Vjet 50 km/s, rjet = 4 cm, and length 10 cm. The modeling research is assessing ram-pressure amplification and Mach-number degradation during liner convergence, evolution of liner non-uniformity amplitude and mode number, and exploration of PJMIF configurations with promising 1D and 2D fusion gains. Conical multi-jet-merging and full-4 π experiments will commence in Fall, 2016 and late 2017, respectively. Supported by the ARPA-E ALPHA Program.

The impact of different types of textile liners used in protective footwear on the subjective sensations of firefighters.

PubMed

Irzmańska, Emilia

2015-03-01

The paper presents ergonomic evaluation of footwear used with three types of textile liners differing in terms of design and material composition. Two novel textile composite liners with enhanced hygienic properties were compared with a standard liner used in firefighter boots. The study involved 45 healthy firefighters from fire and rescue units who wore protective footwear with one of the three types of liners. The study was conducted in a laboratory under a normal atmosphere. The ergonomic properties of the protective footwear and liners were evaluated according to the standard EN ISO 20344:2012 as well as using an additional questionnaire concerning the thermal and moisture sensations experienced while wearing the footwear. The study was conducted on a much larger group of subjects (45) than that required by the ISO standard (3) to increase the reliability of subjective evaluations. Some statistically significant differences were found between the different types of textile liners used in firefighter boots. It was confirmed that the ergonomic properties of protective footwear worn in the workplace may be improved by the use of appropriate textile components. Copyright © 2014 Elsevier Ltd and The Ergonomics Society. All rights reserved.

Method of lining a vertical mine shaft with concrete

DOEpatents

Eklund, James D.; Halter, Joseph M.; Rasmussen, Donald E.; Sullivan, Robert G.; Moffat, Robert B.

1981-01-01

The apparatus includes a cylindrical retainer form spaced inwardly of the wall of the shaft by the desired thickness of the liner to be poured and having overlapping edges which seal against concrete flow but permit the form to be contracted to a smaller circumference after the liner has hardened and is self-supporting. A curb ring extends downwardly and outwardly toward the shaft wall from the bottom of the retainer form to define the bottom surface of each poured liner section. An inflatable toroid forms a seal between the curb ring and the shaft wall. A form support gripper ring having gripper shoes laterally extendable under hydraulic power to engage the shaft wall supports the retainer form, curb ring and liner until the newly poured liner section becomes self-supporting. Adjusting hydraulic cylinders permit the curb ring and retainer form to be properly aligned relative to the form support gripper ring. After a liner section is self-supporting, an advancing system advances the retainer form, curb ring and form support gripper ring toward a shaft boring machine above which the liner is being formed. The advancing system also provides correct horizontal alignment of the form support gripper ring.

Formation of Imploding Plasma Liners for HEDP and MIF Applications - Diagnostics

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

Gilmore, Mark; Hsu, Scott; Witherspoon, F. Douglas

The goal of the plasma liner experiment (PLX) was to explore and demonstrate the feasibility of forming imploding spherical plasma liners that can reach High Energy Density (HED)-relevant (~ 0.1 Mbar) pressures upon stagnation. The plasma liners were to be formed by a spherical array of 30 – 36 railgun-driven hypervelocity plasma jets (Mach 10 – 50). Due to funding and project scope reductions in year two of the project, this initial goal was revised to focus on studies of individual jet propagation, and on two jet merging physics. PLX was a collaboration between a number of partners including Losmore » Alamos National Laboratory, HyperV Technologies, University of New Mexico (UNM), University of Alabama, Huntsville, and University of Nevada, Reno. UNM’s part in the collaboration was primary responsibility for plasma diagnostics. Though full plasma liner experiments could not be performed, the results of single and two jet experiments nevertheless laid important groundwork for future plasma liner investigations. Though challenges were encountered, the results obtained with one and two jets were overwhelmingly positive from a liner formation point of view, and were largely in agreement with predictions of hydrodynamic models.« less

FIELD VERIFICATION OF LINERS FROM SANITARY LANDFILLS

EPA Science Inventory

Liner specimens from three existing landfill sites were collected and examined to determine the changes in their physical properties over time and to validate data being developed through laboratory research. Samples examined included a 15-mil PVC liner from a sludge lagoon in Ne...

49 CFR 193.2187 - Nonmetallic membrane liner.

Code of Federal Regulations, 2010 CFR

2010-10-01

... MATERIALS SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) PIPELINE SAFETY LIQUEFIED NATURAL GAS FACILITIES: FEDERAL SAFETY STANDARDS Design Lng Storage Tanks § 193.2187 Nonmetallic membrane liner. A flammable nonmetallic membrane liner may not be used as an inner container in a storage tank...

Manufacturing Complicated Shells And Liners

NASA Technical Reports Server (NTRS)

Sobol, Paul J.; Faucher, Joseph E.

1993-01-01

Explosive forming, wax filling, and any one of welding, diffusion bonding, or brazing used in method of manufacturing large, complicated shell-and-liner vessels or structures. Method conceived for manufacture of film-cooled rocket nozzles but applicable to joining large coaxial shells and liners in general.

Ground Runup Noise Suppression Program. Part 3. Dry Suppressor Technology Base.

DTIC Science & Technology

1982-06-20

ref 7) used mineral wool to fill the bays. A facing of corrugated metal liner supports the mineral wool . During operation two types of problems...1978 52 tube. The hot jet velocity exhaust flow shifted/decinerated the mineral wool and caused the metal liner to crack/break off. Programs were...PREDICTED) 0 MINERAL WOOL FIBROUS LINER 315 630 1250 2500 5000 10000 20000 1/15 SCALE FREQUENCY Figure 2-30. Noise attenuation of liners in augmenter. K

Waste gas storage

NASA Technical Reports Server (NTRS)

Vickers, Brian D. (Inventor)

1994-01-01

Method for storing a waste gas mixture comprised of nitrogen, oxygen, carbon dioxide, and inert gases, the gas mixture containing corrosive contaminants including inorganic acids and bases and organic solvents, and derived from space station operations. The gas mixture is stored under pressure in a vessel formed of a filament wound composite overwrap on a metal liner, the metal liner being pre-stressed in compression by the overwrap, thereby avoiding any tensile stress in the liner, and preventing stress corrosion cracking of the liner during gas mixture storage.

Cost Estimate for Gun Liner Emplacement

DTIC Science & Technology

2011-08-01

material. The M2 machine gun has a Stellite 21 liner that covers only about one-half of the barrel length. It has been successful in reducing the...Michael R. M2 Machine Gun Barrel Wear with SLAP Ammunition. To be published in Journal of Materials and Manufacturing Processes. 8. Miller, Mark D...case in point is the use of a Stellite 21 liner in the M2 0.50-cal machine gun . However, liners have generally been difficult to place into gun tubes

Subscale Fast Cookoff Testing and Modeling for the Hazard Assessment of Large Rocket Motors

DTIC Science & Technology

2001-03-01

41 LIST OF TABLES Table 1 Heats of Vaporization Parameter for Two-liner Phase Transformation - Complete Liner Sublimation and/or Combined Liner...One-dimensional 2-D Two-dimensional ALE3D Arbitrary-Lagrange-Eulerian (3-D) Computer Code ALEGRA 3-D Arbitrary-Lagrange-Eulerian Computer Code for...case-liner bond areas and in the grain inner bore to explore the pre-ignition and ignition phases , as well as burning evolution in rocket motor fast

Optimization simulated injection molding process for ultrahigh molecular weight polyethylene nanocomposite hip liner using response surface methodology and simulation of mechanical behavior.

PubMed

Heidari, Behzad Shiroud; Davachi, Seyed Mohammad; Moghaddam, Amin Hedayati; Seyfi, Javad; Hejazi, Iman; Sahraeian, Razi; Rashedi, Hamid

2018-05-01

In this study, injection molding process of ultrahigh molecular weight polyethylene (UHMWPE) reinforced with nano-hydroxyapatite (nHA) was simulated and optimized through minimizing the shrinkage and warpage of the hip liners as an essential part of a hip prosthesis. Fractional factorial design (FFD) was applied to the design of the experiment, modeling, and optimizing the shrinkage and warpage of UHMWPE/nHA composite liners. The Analysis of variance (ANOVA) was applied to find the importance of operative parameters and their effects. In this experiment, seven input parameters were surveyed, including mold temperature (A), melt temperature (B), injection time (C), packing time (D), packing pressure (E), coolant temperature (F), and type of liner (G). Two models were capable of predicting warpage and volumetric shrinkage (%) in different conditions with R 2 of 0.9949 and 0.9989, respectively. According to the models, the optimized values of warpage and volumetric shrinkage are 0.287222 mm and 13.6613%, respectively. Meanwhile, a finite element analysis (FE analysis) was also carried out to examine the stress distribution in liners under the force values of demanding and daily activities. The Von-Mises stress distribution showed that both of the liners can be applied to all activities with no failure. However, UHMWPE/nHA liner is more resistant to the highest loads than UHMWPE liner due to the effect of nHA in the nanocomposite. Finally, according to the results of injection molding simulations, optimization, structural analysis as well as the tensile strength and wear resistance, UHMWPE/nHA liner is recommended for the production of a hip prosthesis. Copyright © 2018 Elsevier Ltd. All rights reserved.

Evaluation of a new methodology to simulate damage and wear of polyethylene hip replacements subjected to edge loading in hip simulator testing.

PubMed

Partridge, Susan; Tipper, Joanne L; Al-Hajjar, Mazen; Isaac, Graham H; Fisher, John; Williams, Sophie

2018-05-01

Wear and fatigue of polyethylene acetabular cups have been reported to play a role in the failure of total hip replacements. Hip simulator testing under a wide range of clinically relevant loading conditions is important. Edge loading of hip replacements can occur following impingement under extreme activities and can also occur during normal gait, where there is an offset deficiency and/or joint laxity. This study evaluated a hip simulator method that assessed wear and damage in polyethylene acetabular liners that were subjected to edge loading. The liners tested to evaluate the method were a currently manufactured crosslinked polyethylene acetabular liner and an aged conventional polyethylene acetabular liner. The acetabular liners were tested for 5 million standard walking cycles and following this 5 million walking cycles with edge loading. Edge loading conditions represented a separation of the centers of rotation of the femoral head and the acetabular liner during the swing phase, leading to loading of the liner rim on heel strike. Rim damage and cracking was observed in the aged conventional polyethylene liner. Steady-state wear rates assessed gravimetrically were lower under edge loading compared to standard loading. This study supports previous clinical findings that edge loading may cause rim cracking in liners, where component positioning is suboptimal or where material degradation is present. The simulation method developed has the potential to be used in the future to test the effect of aging and different levels of severity of edge loading on a range of cross-linked polyethylene materials. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 106B: 1456-1462, 2018. © 2017 Wiley Periodicals, Inc.

The effectiveness of cut-proof glove liners: cut and puncture resistance, dexterity, and sensibility.

PubMed

Salkin, J A; Stuchin, S A; Kummer, F J; Reininger, R

1995-11-01

Five types of commercial glove liners (within double latex gloves) were compared to single and double latex gloves for cut and puncture resistance and for relative manual dexterity and degree of sensibility. An apparatus was constructed to test glove-pseudofinger constructs in either a cutting or puncture mode. Cutting forces, cutting speed, and type of blade (serrated or scalpel blade) were varied and the time to cut-through measured by an electrical conductivity circuit. Penetration forces were similarly determined with a scalpel blade and a suture needle using a spring scale loading apparatus. Dexterity was measured with an object placement task among a group of orthopedic surgeons. Sensibility was assessed with Semmes-Weinstein monofilaments, two-point discrimination, and vibrametry using standard techniques and rating scales. A subjective evaluation was performed at the end of testing. Time to cut-through for the liners ranged from 2 to 30 seconds for a rapid oscillating scalpel and 4 to 40 seconds for a rapid oscillating serrated knife under minimal loads. When a 1 kg load was added, times to cut-through ranged from 0.4 to 1.0 second. In most cases, the liners were superior to double latex. On average, 100% more force was required to penetrate the liners with a scalpel and 50% more force was required to penetrate the liners with a suture needle compared to double latex. Object placement task times were not significantly liners compared to double latex gloves. Semmes-Weinstein monofilaments, two-point discrimination, and vibrametry showed no difference in sensibility among the various liners and double latex gloves. Subjects felt that the liners were minimally to moderately impairing. An acclimation period may be required for their effective use.

Spacing of Imbricated Thrust Faults and the Strength of Thrust-Belts and Accretionary Wedges

NASA Astrophysics Data System (ADS)

Ito, G.; Regensburger, P. V.; Moore, G. F.

2017-12-01

The pattern of imbricated thrust blocks is a prominent characteristic of the large-scale structure of thrust-belts and accretionary wedges around the world. Mechanical models of these systems have a rich history from laboratory analogs, and more recently from computational simulations, most of which, qualitatively reproduce the regular patterns of imbricated thrusts seen in nature. Despite the prevalence of these patterns in nature and in models, our knowledge of what controls the spacing of the thrusts remains immature at best. We tackle this problem using a finite difference, particle-in-cell method that simulates visco-elastic-plastic deformation with a Mohr-Coulomb brittle failure criterion. The model simulates a horizontal base that moves toward a rigid vertical backstop, carrying with it an overlying layer of crust. The crustal layer has a greater frictional strength than the base, is cohesive, and is initially uniform in thickness. As the layer contracts, a series of thrust blocks immerge sequentially and form a wedge having a mean taper consistent with that predicted by a noncohesive, critical Coulomb wedge. The widths of the thrust blocks (or spacing between adjacent thrusts) are greatest at the front of the wedge, tend to decrease with continued contraction, and then tend toward a pseudo-steady, minimum width. Numerous experiments show that the characteristic spacing of thrusts increases with the brittle strength of the wedge material (cohesion + friction) and decreases with increasing basal friction for low (<8°) taper angles. These relations are consistent with predictions of the elastic stresses forward of the frontal thrust and at what distance the differential stress exceeds the brittle threshold to form a new frontal thrust. Hence the characteristic spacing of the thrusts across the whole wedge is largely inherited at the very front of the wedge. Our aim is to develop scaling laws that will illuminate the basic physical processes controlling systems, as well as allow researchers to use observations of thrust spacing as an independent constraint on the brittle strength of wedges as well as their bases.

Machine Gun Liner Bond Strength

DTIC Science & Technology

2007-08-01

explosive bonding of pure tantalum, several tantalum alloys, and Stellite 25 (an alloy of cobalt, chrome , nickel, and tungsten) in a liner...smoothly as elastic stresses increase in the plug and liner. At a certain level of displacement, the load reaches a peak and then drops sharply. The

LOCATING AND REPAIRING LEAKS IN LANDFILL/IMPOUNDMENT FLEXIBLE MEMBRANE LINERS

EPA Science Inventory

In the United States, the large quantities of solid and hazardous wastes generated each year are commonly disposed of in landfills and surface impoundments. Geomembrane liners (flexible membrane liners, FMLs) are often used to form an impermeable barrier to prevent migration of c...

40 CFR 258.41 - Project XL Bioreactor Landfill Projects.

Code of Federal Regulations, 2010 CFR

2010-07-01

... footprint of the landfill cell. (B) Water collected on the leak detection liner shall be monitored at least... this section is leachate or gas condensate derived from the MSWLF, which may be supplemented with water... determined by the Standard Test Method for Laboratory Determination of Water (Moisture) Content of Soil and...

Design, engineering and evaluation of refractory liners for slagging gasifiers. Final report

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

deTineo, B J; Booth, G; Firestone, R F

1982-08-01

The contract for this program was awarded at the end of September 1978. Work was started on 1 October 1978, on Tasks A, B, and E. Task A, Conceptual Liner Designs, and Task B, Test System Design and Construction, were completed. Task C, Liner Tests, and Task D, Liner Design Evaluation, were to begin upon completion of Task B. Task E, Liner Model Development, is inactive after an initial data compilation and theoretical model development effort. It was to be activated as soon as data were available from Task D. Task F, Liner Design Handbook, was active along with Taskmore » A since the reports of both tasks were to use the same format. At this time, Tasks C, D, and F are not to be completed since funding of this project was phased out by DOE directive. The refractory text facility, which was constructed, was tested and found to perform satisfactorily. It is described in detail, including a hazard analysis which was performed. (LTN)« less

Grazing incidence modeling of a metamaterial-inspired dual-resonance acoustic liner

NASA Astrophysics Data System (ADS)

Beck, Benjamin S.

2014-03-01

To reduce the noise emitted by commercial aircraft turbofan engines, the inlet and aft nacelle ducts are lined with acoustic absorbing structures called acoustic liners. Traditionally, these structures consist of a perforated facesheet bonded on top of a honeycomb core. These traditional perforate over honeycomb core (POHC) liners create an absorption spectra where the maximum absorption occurs at a frequency that is dictated by the depth of the honeycomb core; which acts as a quarter-wave resonator. Recent advances in turbofan engine design have increased the need for thin acoustic liners that are effective at low frequencies. One design that has been developed uses an acoustic metamaterial architecture to improve the low frequency absorption. Specifically, the liner consists of an array of Helmholtz resonators separated by quarter-wave volumes to create a dual-resonance acoustic liner. While previous work investigated the acoustic behavior under normal incidence, this paper outlines the modeling and predicted transmission loss and absorption of a dual-resonance acoustic metamaterial when subjected to grazing incidence sound.

Effect of long-time immersion of soft denture liners in water on viscoelastic properties.

PubMed

Iwasaki, Naohiko; Yamaki, Chisato; Takahashi, Hidekazu; Oki, Meiko; Suzuki, Tetsuya

2017-09-26

Aim of this study was to investigate the effect of long-time immersion of soft denture liners in 37°C water on viscoelastic properties. Six silicone-based and two acrylic resin-based soft denture liners were selected. Cylindrical specimens were stored in distilled water at 37°C for 6 months. Viscoelastic properties, which were instantaneous and delayed elastic displacements, viscous flow, and residual displacement, were determined using a creep meter, and analyzed with 2-way analysis of variance and Tukey's comparison (α=0.05). Viscoelastic properties and their time-dependent changes were varied among materials examined. The observed viscoelastic properties of three from six silicone-based liners did not significantly change after 6-month immersion, but those of two acrylic resin-based liners significantly changed with the increase of immersion time. However, the sum of initial instantaneous elastic displacement and delayed elastic displacement of two acrylic resin-based liners during 6-month immersion changed less than 10%, which might indicate clinically sufficient elastic performance.

High-performance fiber/epoxy composite pressure vessels

NASA Technical Reports Server (NTRS)

Chiao, T. T.; Hamstad, M. A.; Jessop, E. S.; Toland, R. H.

1978-01-01

Activities described include: (1) determining the applicability of an ultrahigh-strength graphite fiber to composite pressure vessels; (2) defining the fatigue performance of thin-titanium-lined, high-strength graphite/epoxy pressure vessel; (3) selecting epoxy resin systems suitable for filament winding; (4) studying the fatigue life potential of Kevlar 49/epoxy pressure vessels; and (5) developing polymer liners for composite pressure vessels. Kevlar 49/epoxy and graphite fiber/epoxy pressure vessels, 10.2 cm in diameter, some with aluminum liners and some with alternation layers of rubber and polymer were fabricated. To determine liner performance, vessels were subjected to gas permeation tests, fatigue cycling, and burst tests, measuring composite performance, fatigue life, and leak rates. Both the metal and the rubber/polymer liner performed well. Proportionately larger pressure vessels (20.3 and 38 cm in diameter) were made and subjected to the same tests. In these larger vessels, line leakage problems with both liners developed the causes of the leaks were identified and some solutions to such liner problems are recommended.

Effects of state recovery on creep buckling under variable loading

NASA Technical Reports Server (NTRS)

Robinson, D. N.; Arnold, S. M.

1986-01-01

Structural alloys embody internal mechanisms that allow recovery of state with varying stress and elevated temperature, i.e., they can return to a softer state following periods of hardening. Such material behavior is known to strongly influence structural response under some important thermomechanical loadings, for example, that involving thermal ratchetting. The influence of dynamic and thermal recovery on the creep buckling of a column under variable loading is investigated. The column is taken as the idealized (Shanley) sandwich column. The constitutive model, unlike the commonly employed Norton creep model, incorporates a representation of both dynamic and thermal (state) recovery. The material parameters of the constitutive model are chosen to characterize Narloy Z, a representative copper alloy used in thrust nozzle liners of reusable rocket engines. Variable loading histories include rapid cyclic unloading/reloading sequences and intermittent reductions of load for extended periods of time; these are superimposed on a constant load. The calculated results show that state recovery significantly affects creep buckling under variable loading. Structural alloys embody internal mechanisms that allow recovery of state with varying stress and time.

Mathematical Modelling of Liner Piston Maintenance Activity using Field Data to Minimize Overhauling Time and Human Energy Consumption

NASA Astrophysics Data System (ADS)

Belkhode, Pramod Namdeorao

2017-06-01

Field data based model is proposed to reduce the overhauling time and human energy consumed in liner piston maintenance activity so as to increase the productivity of liner piston maintenance activity. The independent variables affecting the phenomenon such as anthropometric parameters of workers (Eastman Kodak Co. Ltd in Section VIA Appendix-A: Anthropometric Data. Ergonomic Design for People at Work, Van Nostrans Reinhold, New York, 1), workers parameters, specification of liner piston data, specification of tools used in liner piston maintenance activity, specification of solvents, axial clearance of big end bearing and bolt elongation, workstation data (Eastman Kodak Co. Ltd in Work Place Ergonomic Design for People at Work, Van Nostrans Reinhold, New York, 2) and extraneous variables, namely, temperature, humidity at workplace, illumination at workplace and noise at workplace (Eastman Kodak Co. Ltd in Chapter V Environment Ergonomic Design for People at Work, Van Nostrans Reinhold, New York, 3) are taken into account. The model is formulated for dependent variables of liner piston maintenance activity to minimize the overhauling time and human energy consumption so as to improve the productivity of liner piston maintenance activity. The developed model can predict the performance of liner piston maintenance activity which involves man and machine system (Schenck in Theories of Engineering Experimentation, Mc-Graw Hill, New York 4). The model is then optimized by optimization technique and the sensitivity analysis of the model has also been estimated.

Performance evaluation of a newly developed variable rate sprayer for nursery liner applications

USDA-ARS?s Scientific Manuscript database

An experimental variable-rate sprayer designed for liner applications was tested by comparing its spray deposit, coverage, and droplet density inside canopies of six nursery liner varieties with constant-rate applications. Spray samplers, including water sensitive papers (WSP) and nylon screens, wer...

Optimal Spray Application Rates for Ornamental Nursery Liner Production

USDA-ARS?s Scientific Manuscript database

Spray deposition and coverage at different application rates for nursery liners of different sizes were investigated to determine the optimal spray application rates. Experiments were conducted on two and three-year old red maple liners. A traditional hydraulic sprayer with vertical booms was used t...

40 CFR 503.23 - Pollutant limits (other than domestic septage).

Code of Federal Regulations, 2011 CFR

2011-07-01

... limits (other than domestic septage). (a) Active sewage sludge unit without a liner and leachate... Concentrations—Active Sewage Sludge Unit Without a Liner and Leachate Collection Pollutant Concentration... Without a Liner and Leachate Collection System That Has a Unit Boundary to Property Line Distance Less...

40 CFR 503.23 - Pollutant limits (other than domestic septage).

Code of Federal Regulations, 2010 CFR

2010-07-01

... limits (other than domestic septage). (a) Active sewage sludge unit without a liner and leachate... Concentrations—Active Sewage Sludge Unit Without a Liner and Leachate Collection Pollutant Concentration... Without a Liner and Leachate Collection System That Has a Unit Boundary to Property Line Distance Less...

40 CFR 503.23 - Pollutant limits (other than domestic septage).

Code of Federal Regulations, 2013 CFR

2013-07-01

... limits (other than domestic septage). (a) Active sewage sludge unit without a liner and leachate... Concentrations—Active Sewage Sludge Unit Without a Liner and Leachate Collection Pollutant Concentration... Without a Liner and Leachate Collection System That Has a Unit Boundary to Property Line Distance Less...

40 CFR 503.23 - Pollutant limits (other than domestic septage).

Code of Federal Regulations, 2012 CFR

2012-07-01

... limits (other than domestic septage). (a) Active sewage sludge unit without a liner and leachate... Concentrations—Active Sewage Sludge Unit Without a Liner and Leachate Collection Pollutant Concentration... Without a Liner and Leachate Collection System That Has a Unit Boundary to Property Line Distance Less...

40 CFR 503.23 - Pollutant limits (other than domestic septage).

Code of Federal Regulations, 2014 CFR

2014-07-01

... limits (other than domestic septage). (a) Active sewage sludge unit without a liner and leachate... Concentrations—Active Sewage Sludge Unit Without a Liner and Leachate Collection Pollutant Concentration... Without a Liner and Leachate Collection System That Has a Unit Boundary to Property Line Distance Less...

HYDRAULIC CONDUCTIVITY OF THREE GEOSYNTHETIC CLAY LINERS

EPA Science Inventory

The hydraulic conductivity of three 2.9 m² (32 sq ft) geosynthetic clay liners (GCLs) was measured. Tests were performed on individual sheets of the GCLs, on overlapped pieces of GCLs, and on composite liners consisting of a punctured geomembrane overlying a GCL. Hyd...

Variable volume combustor

DOEpatents

Ostebee, Heath Michael; Ziminsky, Willy Steve; Johnson, Thomas Edward; Keener, Christopher Paul

2017-01-17

The present application provides a variable volume combustor for use with a gas turbine engine. The variable volume combustor may include a liner, a number of micro-mixer fuel nozzles positioned within the liner, and a linear actuator so as to maneuver the micro-mixer fuel nozzles axially along the liner.

Evaluate the Effect of Commercially Available Denture Cleansers on Surface Hardness and Roughness of Denture Liners at Various Time Intervals

PubMed Central

Mohammed, Hilal S.; Singh, Sumeet; Hari, Prasad A.; Amarnath, G. S.; Kundapur, Vinaya; Pasha, Naveed; Anand, M.

2016-01-01

Background and objective: Chemical cleansing by denture cleansers is first choice for denture plaque control. The most common problems while using denture cleansers are hardening, porosity, odor sorption, water sorption, solubility, and colour change, bacterial and fungal growth. Chemical cleansing procedures have been found to have an effect on the physical and mechanical properties of denture liners. Thus, this study was conducted to evaluate the effect of commercially available denture cleansers on surface hardness and roughness of acrylic and silicon based denture liners at various time interval. Method: Two autopolymerising denture liners Kooliner (acrylic) and GC reline soft (silicon) were tested with two commercially available denture cleansers, polident and efferdent plus. Total of 120 specimens were prepared and all the specimens were divided into six groups based on the relining materials and denture cleansers used. Surface hardness and surface roughness was tested using Shore A durometer and profilometer respectively at the end of day 1, day 7, day 30 and day 90. All the specimens were stored in artificial saliva throughout the study. Cleanser solution was prepared daily by adding Polident and Efferdent plus denture cleanser tablet into 250ml of enough very warm (not hot) water. Acrylic and silicon liner groups were cleansed in a solution of denture cleanser and water for 15 minutes daily, rinsed with water and stored in artificial saliva at room temperature. The data was analyzed with one way ANOVA and independent t-test. Result: The acrylic soft lining showed gradual hardening and increase in surface roughness after immersion in denture cleanser and also with time. Acrylic liner material showed maximum hardness and roughness with Polident followed by Efferdent plus and water (control group). Silicone lining material showed a slight difference in hardness and roughness between the test group and control group. There was a slight increase in hardness in all the groups with time. Very slight increase in mean surface roughness of all the silicon liner groups from day 1 to day 90 was observed. A statistically significant change was noted between and within the all silicon liner groups on day 7, day 30 and day 90. Conclusion: The average surface hardness and surface roughness were lower in silicon liner material than acrylic liner material. Maximum surface roughness was noted by Polident followed by Efferdent Plus and Water for both acrylic liner group and silicon liner group. PMID:28190983

USER'S GUIDE TO FLEXIBLE MEMBRANE LINER ADVISORY EXPERT SYSTEM: FLEX VERSION 3.0

EPA Science Inventory

The guide is a user manual for the Flexible Membrane Liner Advisory Expert System (FLEX). The system assists in determining if a proposed synthetic liner material will be chemically resistant to a proposed or anticipated leachate from a hazardous waste land disposal site. More sp...

76 FR 63571 - Airworthiness Directives; Eclipse Aerospace, Inc. Airplanes Equipped With Pratt & Whitney Canada...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-10-13

... design change for the combustion chamber liner assembly. This proposed AD would retain the requirements... design change to the combustion chamber liner assembly. The current design of the combustion chamber liner assembly is a one- piece configuration. The new design change involves replacing the combustion...

Review and Evaluation of Analyses on the Economic Impact of Rate and Service Cooperation by Ocean Liner Companies

DOT National Transportation Integrated Search

1984-03-01

The literature on liner shipping companies is reviewed and discussed. The first section of the report examines the argument that liner shipping has unique characteristics that require a special public policy as regards monopoly and anti-trust legisla...

CONSTRUCTION, MONITORING, AND PERFORMANCE OF TWO SOIL LINERS

EPA Science Inventory

A prototype soil liner and a field-scale soil liner were constructed to test whether compacted soil barrier systems could be built to meet the standard set by the U.S. Environmental Protection Agency (EPA) for saturated hydraulic conductivity (< 1 x 10'7 cm/s). In situ ponded inf...

Method and Apparatus for Monitoring the Integrity of a Geomembrane Liner using time Domain Reflectometry

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

Morris, John L.

1998-11-09

Leaks are detected in a multi-layered geomembrane liner by a two-dimensional time domain reflectometry (TDR) technique. The TDR geomembrane liner is constructed with an electrically conductive detection layer positioned between two electrically non-conductive dielectric layers, which are each positioned between the detection layer and an electrically conductive reference layer. The integrity of the TDR geomembrane liner is determined by generating electrical pulses within the detection layer and measuring the time delay for any reflected electrical energy caused by absorption of moisture by a dielectric layer.

Tokamak with mechanical compression of toroidal magnetic field

DOEpatents

Ohkawa, Tihiro

1981-01-01

A tokamak apparatus includes a pressure vessel for defining a reservoir and confining liquid therein. A collapsible toroidal liner disposed within the pressure vessel defines a toroidal space within the liner. Liquid metal fills the reservoir outside said liner. A toroidal magnetic field is developed within the toroidal space about the major axis thereof. A toroidal plasma is developed within the toroidal space about the major axis thereof. Pressure is applied to the liquid metal to collapse the liner and reduce the volume of the toroidal space, thereby increasing the toroidal magnetic flux density therein.

Method and apparatus for monitoring the integrity of a geomembrane liner using time domain reflectometry

DOEpatents

Morrison, John L [Idaho Falls, ID

2001-04-24

Leaks are detected in a multi-layered geomembrane liner by a two-dimensional time domain reflectometry (TDR) technique. The TDR geomembrane liner is constructed with an electrically conductive detection layer positioned between two electrically non-conductive dielectric layers, which are each positioned between the detection layer and an electrically conductive reference layer. The integrity of the TDR geomembrane liner is determined by generating electrical pulses within the detection layer and measuring the time delay for any reflected electrical energy caused by absorption of moisture by a dielectric layer.

Nondestructive evaluation of ceramic matrix composite combustor components.

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

Sun, J. G.; Verrilli, M. J.; Stephan, R.

Combustor liners fabricated from a SiC/SiC composite were nondestructively interrogated before and after combustion rig testing. The combustor liners were inspected by X-ray, ultrasonic and thermographic techniques. In addition, mechanical test results were obtained from witness coupons, representing the as-manufactured liners, and from coupons machined from the components after combustion exposure. Thermography indications were found to correlate with reduced material properties obtained after rig testing. Microstructural examination of the SiC/SiC liners revealed the thermography indications to be delaminations and damaged fiber tows.

Matching an Inductive Accumulator and a System of Acceleration of a Liner with Limitation of the Breaking Voltage,

DTIC Science & Technology

In this work calculations are made of the efficiencies of acceleration of a liner from an inductive accumulator in the mode theta-pinch and Z-pinch...to the speed of the liner . Estimations have been made of the necessary power at the moment of switching the current on the basis of considerations of...the stability of the pinch effect of the liner . The level of energies necessary for the creation of a thermonuclear reactor on the basis of theta

Failure mechanisms and closed reduction of a constrained tripolar acetabular liner.

PubMed

Robertson, William J; Mattern, Christopher J; Hur, John; Su, Edwin P; Pellicci, Paul M

2009-02-01

Unlike traditional bipolar constrained liners, the Osteonics Omnifit constrained acetabular insert is a tripolar device, consisting of an inner bipolar bearing articulating within an outer, true liner. Every reported failure of the Omnifit tripolar implant has been by failure at the shell-bone interface (Type I failure), failure at the shell-liner interface (Type II failure), or failure of the locking mechanism resulting in dislocation of the bipolar-liner interface (Type III failure). In this report we present two cases of failure of the Omnifit tripolar at the bipolar-femoral head interface. To our knowledge, these are the first reported cases of failure at the bipolar-femoral head interface (Type IV failure). In addition, we described the first successful closed reduction of a Type IV failure.

Design of crusher liner based on time - varying uncertainty theory

NASA Astrophysics Data System (ADS)

Tang, J. C.; Shi, B. Q.; Yu, H. J.; Wang, R. J.; Zhang, W. Y.

2017-09-01

This article puts forward the time-dependent design method considering the load fluctuation factors for the liner based on the time-varying uncertainty theory. In this method, the time-varying uncertainty design model of liner is constructed by introducing the parameters that affect the wear rate, the volatility and the drift rate. Based on the design example, the timevarying design outline of the moving cone liner is obtained. Based on the theory of minimum wear, the gap curve of wear resistant cavity is designed, and the optimized cavity is obtained by the combination of the thickness of the cone and the cavity gap. Taking the PYGB1821 multi cylinder hydraulic cone crusher as an example, it is proved that the service life of the new liner is improved by more than 14.3%.

On the attenuation of sound by three-dimensionally segmented acoustic liners in a rectangular duct

NASA Technical Reports Server (NTRS)

Koch, W.

1979-01-01

Axial segmentation of acoustically absorbing liners in rectangular, circular or annual duct configurations is a very useful concept for obtaining higher noise attenuation with respect to the bandwidth of absorption as well as the maximum attenuation. As a consequence, advanced liner concepts are proposed which induce a modal energy transfer in both cross-sectional directions to further reduce the noise radiated from turbofan engines. However, these advanced liner concepts require three-dimensional geometries which are difficult to treat theoretically. A very simple three-dimensional problem is investigated analytically. The results show a strong dependence on the positioning of the liner for some incident source modes while the effect of three-dimensional segmentation appears to be negligible over the frequency range considered.

Aerodynamic design of the contoured wind-tunnel liner for the NASA supercritical, laminar-flow-control, swept-wing experiment

NASA Technical Reports Server (NTRS)

Newman, P. A.; Anderson, E. C.; Peterson, J. B., Jr.

1984-01-01

An overview is presented of the entire procedure developed for the aerodynamic design of the contoured wind tunnel liner for the NASA supercritical, laminar flow control (LFC), swept wing experiment. This numerical design procedure is based upon the simple idea of streamlining and incorporates several transonic and boundary layer analysis codes. The liner, presently installed in the Langley 8 Foot Transonic Pressure Tunnel, is about 54 ft long and extends from within the existing contraction cone, through the test section, and into the diffuser. LFC model testing has begun and preliminary results indicate that the liner is performing as intended. The liner design results presented in this paper, however, are examples of the calculated requirements and the hardware implementation of them.

Plasma-Jet-Driven Magneto-Inertial Fusion (PJMIF): Physics and Design for a Plasma Liner Formation Experiment

NASA Astrophysics Data System (ADS)

Hsu, Scott; Cassibry, Jason; Witherspoon, F. Douglas

2014-10-01

Spherically imploding plasma liners are a potential standoff compression driver for magneto-inertial fusion, which is a hybrid of and operates in an intermediate density between those of magnetic and inertial fusion. We propose to use an array of merging supersonic plasma jets to form a spherically imploding plasma liner. The jets are to be formed by pulsed coaxial guns with contoured electrodes that are placed sufficiently far from the location of target compression such that no hardware is repetitively destroyed. As such, the repetition rate can be higher (e.g., 1 Hz) and ultimately the power-plant economics can be more attractive than most other MIF approaches. During the R&D phase, a high experimental shot rate at reasonably low cost (e.g., < 1 k/shot) may be achieved with excellent diagnostic access, thus enabling a rapid learning rate. After some background on PJMIF and its prospects for reactor-relevant energy gain, this poster describes the physics objectives and design of a proposed 60-gun plasma-liner-formation experiment, which will provide experimental data on: (i) scaling of peak liner ram pressure versus initial jet parameters, (ii) liner non-uniformity characterization and control, and (iii) control of liner profiles for eventual gain optimization.

Acoustic Characteristics of Various Treatment Panel Designs for HSCT Ejector Liner Acoustic Technology Development Program

NASA Technical Reports Server (NTRS)

Salikuddin, M.; Kraft, R. E.; Syed, A. a.; Vu, D. D.; Mungur, P.; Langenbrunner, L. E.; Majjigi, R. K.

2006-01-01

The objectives of the initial effort (Phase I) of HSR Liner Technology Program, the selection of promising liner concepts, design and fabrication of these concepts for laboratory tests, testing these liners in the laboratory by using impedance tube and flow ducts, and developing empirical impedance/suppression correlation, are successfully completed. Acoustic and aerodynamic criteria for the liner design are established. Based on these criteria several liners are designed. The liner concepts designed and fabricated include Single-Degree-of-Freedom (SDOF), Two-Degree-of-Freedom (2DOF), and Bulk Absorber. Two types of SDOF treatment are fabricated, one with a perforated type face plate and the other with a wiremesh (woven) type faceplate. In addition, special configurations of these concepts are also included in the design. Several treatment panels are designed for parametric study. In these panels the facesheets of different porosity, hole diameter, and sheet thickness are utilized. Several deep panels (i.e., 1 in. deep) are designed and instrumented to measure DC flow resistance and insitu impedance in the presence of grazing flow. Basic components of these panels (i.e., facesheets, bulk materials, etc.) are also procured and tested. The results include DC flow resistance, normal impedance, and insertion loss.

Numerical study on the lubrication performance of compression ring-cylinder liner system with spherical dimples

PubMed Central

Liu, Cheng; Zhang, Yong-Fang; Li, Sha; Müller, Norbert

2017-01-01

The effects of surface texture on the lubrication performance of a compression ring-cylinder liner system are studied in this paper. By considering the surface roughness of the compression ring and cylinder liner, a mixed lubrication model is presented to investigate the tribological behaviors of a barrel-shaped compression ring-cylinder liner system with spherical dimples on the liner. In order to determine the rupture and reformulation positions of fluid film accurately, the Jacoboson-Floberg-Olsson (JFO) cavitation boundary condition is applied to the mixed lubrication model for ensuring the mass-conservative law. On this basis, the minimum oil film thickness and average friction forces in the compression ring-cylinder liner system are investigated under the engine-like conditions by changing the dimple area density, radius, and depth. The wear load, average friction forces, and power loss of the compression ring-cylinder liner system with and without dimples are also compared for different compression ring face profiles. The results show that the spherical dimples can produce a larger reduction of friction in mixed lubrication region, and reduce power loss significantly in the middle of the strokes. In addition, higher reduction percentages of average friction forces and wear are obtained for smaller crown height or larger axial width. PMID:28732042

The Usability of a Pressure-Indicating Film to Measure the Teat Load Caused by a Collapsing Liner

PubMed Central

Demba, Susanne; Elsholz, Sabrina; Ammon, Christian; Rose-Meierhöfer, Sandra

2016-01-01

Prevention of damage to the teat and mastitis requires determination of the teat load caused by a collapsing liner. The aim of this study was to test a pressure-indicating film designed to measure the pressure between a collapsing liner and artificial teats. The Ultra Super Low and the Extreme Low pressure-indicating films were tested on two types of artificial teat. The experiments were performed with a conventional milking cluster equipped with round silicone liners. For each teat and film type, 30 repetitions were performed. Each repetition was performed with a new piece of film. Kruskal-Wallis tests were performed to detect differences between the pressure values for the different teats. The area of regions where pressure-indication color developed was calculated to determine the most suitable film type. Both film types measured the pressure applied to both artificial teats by the teat cup liner. Thus, the pressure-indicating films can be used to measure the pressure between a collapsing liner and an artificial teat. Based on the results of the present investigation, a pressure-indicating film with the measurement ranges of both film types combined would be an optimal tool to measure the overall pressure between an artificial teat and a collapsing liner. PMID:27690033

FGD liner experiments with wetlands

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

Mitsch, W.J.; Ahn, C.; Wolfe, W.E.

1999-07-01

The construction of artificial wetlands for wastewater treatment often requires impermeable liners not only to protect groundwater resources but also to ensure that there is adequate water in the wetland to support appropriate aquatic life, particularly wetland vegetation. Liners or relatively impervious site soils are very important to the success of constructed treatment wetlands in areas where ground water levels are typically close to the ground surface. This study, carried out at the Olentangy River Wetland Research Park, investigated the use of FGD material from sulfur scrubbers as a possible liner material for constructed wetlands. While several studies have investigatedmore » the use of FGD material to line ponds, no studies have investigated the use of this material as a liner for constructed wetlands. They used experimental mesocosms to see the effect of FGD liner materials in constructed wetlands on water quality and on wetland plant growth. This paper presents the results of nutrient analyses and physicochemical investigation of leachate and surface outflow water samples collected from the mesocosms. Plant growth and biomass of wetland vegetation are also included in this paper. First two year results are reported by Ahn et al. (1998, 1999). The overall goal of this study is the identification of advantages and disadvantages of using FGD by-product as an artificial liner in constructed wetlands.« less

Suppression of Helmholtz resonance using inside acoustic liner

NASA Astrophysics Data System (ADS)

Hong, Zhiliang; Dai, Xiwen; Zhou, Nianfa; Sun, Xiaofeng; Jing, Xiaodong

2014-08-01

When a Helmholtz resonator is exposed to grazing flow, an unstable shear layer at the opening can cause the occurrence of acoustic resonance under appropriate conditions. In this paper, in order to suppress the flow-induced resonance, the effects of inside acoustic liners placed on the side wall or the bottom of a Helmholtz resonator are investigated. Based on the one-dimensional sound propagation theory, the time domain impedance model of a Helmholtz resonator with inside acoustic liner is derived, and then combined with a discrete vortex model the resonant behavior of the resonator under grazing flow is simulated. Besides, an experiment is conducted to validate the present model, showing significant reduction of the peak sound pressure level achieved by the use of the side-wall liners. And the simulation results match reasonably well with the experimental data. The present results reveal that the inside acoustic liner can not only absorb the resonant sound pressure, but also suppress the fluctuation motion of the shear layer over the opening of the resonator. In all, the impact of the acoustic liners is to dampen the instability of the flow-acoustic coupled system. This demonstrates that it is a convenient and effective method for suppressing Helmholtz resonance by using inside acoustic liner.

Impact of landfill liner time-temperature history on the service life of HDPE geomembranes.

PubMed

Rowe, R Kerry; Islam, M Z

2009-10-01

The observed temperatures in different landfills are used to establish a number of idealized time-temperature histories for geomembrane liners in municipal solid waste (MSW) landfills. These are then used for estimating the service life of different HDPE geomembranes. The predicted antioxidant depletion times (Stage I) are between 7 and 750 years with the large variation depending on the specific HDPE geomembrane product, exposure conditions, and most importantly, the magnitude and duration of the peak liner temperature. The higher end of the range corresponds to data from geomembranes aged in simulated landfill liner tests and a maximum liner temperature of 37 degrees C. The lower end of the range corresponds to a testing condition where geomembranes were immersed in a synthetic leachate and a maximum liner temperature of 60 degrees C. The total service life of the geomembranes was estimated to be between 20 and 3300 years depending on the time-temperature history examined. The range illustrates the important role that time-temperature history could play in terms of geomembrane service life. The need for long-term monitoring of landfill liner temperature and for geomembrane ageing studies that will provide improved data for assessing the likely long-term performance of geomembranes in MSW landfills are highlighted.

Acoustic properties and durability of liner materials at non-standard atmospheric conditions

NASA Technical Reports Server (NTRS)

Ahuja, K. K.; Gaeta, R. J., Jr.; Hsu, J. S.

1994-01-01

This report documents the results of an experimental study on how acoustic properties of certain absorbing liner materials are affected by nonstandard atmospheric conditions. This study was motivated by the need to assess risks associated with incorporating acoustic testing capability in wind tunnels with semicryogenic high Reynolds number aerodynamic and/or low pressure capabilities. The study consisted of three phases: 1) measurement of acoustic properties of selected liner materials at subatmospheric pressure conditions, 2) periodic cold soak and high pressure exposure of liner materials for 250 cycles, and 3) determination of the effect of periodic cold soak on the acoustic properties of the liner materials at subatmospheric conditions and the effect on mechanical resiliency. The selected liner materials were Pyrell foam, Fiberglass, and Kevlar. A vacuum facility was used to create the subatmospheric environment in which an impedance tube was placed to measure acoustic properties of the test materials. An automated cryogenic cooling system was used to simulate periodic cold soak and high pressure exposure. It was found that lower ambient pressure reduced the absorption effectiveness of the liner materials to varying degrees. Also no significant change in the acoustic properties occurred after the periodic cold soak. Furthermore, mechanical resiliency tests indicated no noticeable change.

An explosion of a CNG fuel vessel in an urban bus.

PubMed

Park, Chan-Seong; Jeon, Seung-Won; Moon, Jung-Eun; Lee, Kyu-Jung

2010-03-01

An investigation is presented of the explosion of a CNG (compressed natural gas) fuel vessel, called a liner, in an urban bus. The explosion happened at a gas station 10 min after filling was completed. There were no traces of soot and flames at the failed liner, which would be indicative of explosion by ignition of the gas. The filling process of the station was automatically monitored and recorded in a computer. There was no unusual record of the filling system that indicated excess pressure at the time of the accident. There were cracks on the liner that were initiated at the outer surface of the cylindrical shell located at a point 4 cm above the lower dome where cracks did not originate easily as a result of overload. Chemical analysis was performed on a specimen that was cut from the liner, and there was no peculiarity in the mix. Mechanical analysis was performed on the specimens and showed that the hardness was not in the specified range because of inadequate heat treatment of the metal. The hardness of the liner was strictly controlled in the manufacturing process. All the liners that were manufactured at the same period with the failed liner were recalled for examination.

INTERNAL REPAIR OF PIPELINES

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

Bill Bruce; Nancy Porter; George Ritter

2005-07-20

The two broad categories of fiber-reinforced composite liner repair and deposited weld metal repair technologies were reviewed and evaluated for potential application for internal repair of gas transmission pipelines. Both are used to some extent for other applications and could be further developed for internal, local, structural repair of gas transmission pipelines. Principal conclusions from a survey of natural gas transmission industry pipeline operators can be summarized in terms of the following performance requirements for internal repair: (1) Use of internal repair is most attractive for river crossings, under other bodies of water, in difficult soil conditions, under highways, undermore » congested intersections, and under railway crossings. (2) Internal pipe repair offers a strong potential advantage to the high cost of horizontal direct drilling when a new bore must be created to solve a leak or other problem. (3) Typical travel distances can be divided into three distinct groups: up to 305 m (1,000 ft.); between 305 m and 610 m (1,000 ft. and 2,000 ft.); and beyond 914 m (3,000 ft.). All three groups require pig-based systems. A despooled umbilical system would suffice for the first two groups which represents 81% of survey respondents. The third group would require an onboard self-contained power unit for propulsion and welding/liner repair energy needs. (4) The most common size range for 80% to 90% of operators surveyed is 508 mm (20 in.) to 762 mm (30 in.), with 95% using 558.8 mm (22 in.) pipe. Evaluation trials were conducted on pipe sections with simulated corrosion damage repaired with glass fiber-reinforced composite liners, carbon fiber-reinforced composite liners, and weld deposition. Additional un-repaired pipe sections were evaluated in the virgin condition and with simulated damage. Hydrostatic failure pressures for pipe sections repaired with glass fiber-reinforced composite liner were only marginally greater than that of pipe sections without liners, indicating that this type of liner is only marginally effective at restoring the pressure containing capabilities of pipelines. Failure pressures for larger diameter pipe repaired with a semi-circular patch of carbon fiber-reinforced composite lines were also marginally greater than that of a pipe section with un-repaired simulated damage without a liner. These results indicate that fiber reinforced composite liners have the potential to increase the burst pressure of pipe sections with external damage Carbon fiber based liners are viewed as more promising than glass fiber based liners because of the potential for more closely matching the mechanical properties of steel. Pipe repaired with weld deposition failed at pressures lower than that of un-repaired pipe in both the virgin and damaged conditions, indicating that this repair technology is less effective at restoring the pressure containing capability of pipe than a carbon fiber-reinforced liner repair. Physical testing indicates that carbon fiber-reinforced liner repair is the most promising technology evaluated to-date. In lieu of a field installation on an abandoned pipeline, a preliminary nondestructive testing protocol is being developed to determine the success or failure of the fiber-reinforced liner pipeline repairs. Optimization and validation activities for carbon-fiber repair methods are ongoing.« less

Construction and evaluation of simulated pilot scale landfill lysimeter in Bangladesh.

PubMed

Rafizul, Islam M; Howlader, Milon Kanti; Alamgir, Muhammed

2012-11-01

This research concentrates the design, construction and evaluation of simulated pilot scale landfill lysimeter at KUET campus, Khulna, Bangladesh. Both the aerobic and anaerobic conditions having a base liner and two different types of cap liner were simulated. After the design of a reference cell, the construction of landfill lysimeter was started in January 2008 and completed in July 2008. In all construction process locally available civil construction materials were used. The municipal solid waste (MSW) of 2800-2985 kg having the total volume of 2.80 m(3) (height 1.6 m) and moisture content of 65% was deposited in each lysimeter by applying required compaction energy. In contrast, both the composition in terms of methane (CH(4)), carbon dioxide (CO(2)) and oxygen (O(2)) as well as the flow rate of landfill gas (LFG) generated from MSW in landfill lysimeter were measured and varied significantly in relation to the variation of lysimeter operational condition. Moreover, anaerobic lysimeter-C shows the highest composition of LFG in compare to the anaerobic lysimeter-B due to the providing of lower compaction of cap liner in anaerobic lysimeter-C. Here, it is interesting to note that in absence of compacted clay liner (CCL) and hence percolation of rainwater that facilitates rapid degradation of MSW in aerobic lysimeter-A has resulted in the highest settlement than that of anaerobic landfill lysimeter-B and C. Moreover, in case of anaerobic lysimeter-B and C, the leachate generation was lower than that of aerobic lysimeter-A due to the providing of cap liner in anaerobic lysimeter-B and C, played an important role to reduce the percolation of rainwater. The study also reveals that the leachate pollution index (LPI) has decreased in relation to the increasing of elapsed period as well as the LPI for collection system of aerobic lysimeter-A was higher than that of the collection system of anaerobic lysimeter-B and C. Finally, it can be depicted that LPI for lysimeter was significantly high and proper treatment will be necessary before discharging the lysimeter leachate into the water bodies. Copyright © 2012 Elsevier Ltd. All rights reserved.

Advanced Computational and Experimental Techniques for Nacelle Liner Performance Evaluation

NASA Technical Reports Server (NTRS)

Gerhold, Carl H.; Jones, Michael G.; Brown, Martha C.; Nark, Douglas

2009-01-01

The Curved Duct Test Rig (CDTR) has been developed to investigate sound propagation through a duct of size comparable to the aft bypass duct of typical aircraft engines. The axial dimension of the bypass duct is often curved and this geometric characteristic is captured in the CDTR. The semiannular bypass duct is simulated by a rectangular test section in which the height corresponds to the circumferential dimension and the width corresponds to the radial dimension. The liner samples are perforate over honeycomb core and are installed on the side walls of the test section. The top and bottom surfaces of the test section are acoustically rigid to simulate a hard wall bifurcation or pylon. A unique feature of the CDTR is the control system that generates sound incident on the liner test section in specific modes. Uniform air flow, at ambient temperature and flow speed Mach 0.275, is introduced through the duct. Experiments to investigate configuration effects such as curvature along the flow path on the acoustic performance of a sample liner are performed in the CDTR and reported in this paper. Combinations of treated and acoustically rigid side walls are investigated. The scattering of modes of the incident wave, both by the curvature and by the asymmetry of wall treatment, is demonstrated in the experimental results. The effect that mode scattering has on total acoustic effectiveness of the liner treatment is also shown. Comparisons of measured liner attenuation with numerical results predicted by an analytic model based on the parabolic approximation to the convected Helmholtz equation are reported. The spectra of attenuation produced by the analytic model are similar to experimental results for both walls treated, straight and curved flow path, with plane wave and higher order modes incident. The numerical model is used to define the optimized resistance and reactance of a liner that significantly improves liner attenuation in the frequency range 1900-2400 Hz. A liner impedance descriptor is used to determine the liner parameters that achieve the optimum impedance.

Cytotoxic and phytotoxic effects of the main chemical components of spent pot-liner: a comparative approach.

PubMed

Palmieri, Marcel José; Luber, Jaquelini; Andrade-Vieira, Larissa Fonseca; Davide, Lisete Chamma

2014-03-15

Spent pot-liner (SPL) is a hazardous solid waste produced by the aluminum industry. Although its composition may vary, fluoride and cyanide salts as well as aluminum are predominant components. A seed-germination and root-elongation test was performed with Lactuca sativa seeds as a test system. SPL induced decrease of seed germination rate and root elongation. The concentration of 26.5g/L SPL was established from a regression curve as the IC50 (inhibition concentration 50%). Through chemical analyses, the concentrations of fluoride, cyanide and aluminum in SPL solutions of 26.5g/L (IC50), 39.75g/L (1.5IC50) and 13.25g/L (0.5IC50) were determined. Further, a cell-cycle test was conducted with root tips of L. sativa exposed to these same SPL solutions. All test chemicals presented toxic effects on meristematic cells of L. sativa. Aluminum was identified as the SPL component mainly responsible for reduction of the mitotic index. Chromosomal alterations resulted from the interactions among the three main chemical components of SPL, without a clear predominantly responsible agent. Induction of condensed nuclei was mainly due to effects of aluminum and fluoride, and may serve as an indicator of induced cell death. Copyright © 2014 Elsevier B.V. All rights reserved.

Laboratory development and field demonstration of self-sealing/self-healing landfill liner.

PubMed

Shi, Caijun; Booth, Rob

2005-01-01

The self-sealing/self-healing (SS/SH) barrier concept is based on the principle that two or more parent materials placed in vertical or horizontal layers will react at their interfaces to form insoluble reaction products. These products constitute a seamless impermeable seal, which is resistant to the transmission of leachate and contaminants. A SS/SH liner formulation was developed in the laboratory and demonstrated at the Sudokwon landfill site in South Korea. Laboratory testing results indicated that a seal with a hydraulic conductivity less than 10(-9) m/s formed after two to four weeks of curing at room temperature, and the seal healed itself after it was fractured. The use of the soil from the Sudokwon landfill site instead of sand as the matrix of the parent materials in the SS/SH liner retarded the sealing and healing of the seal, but did not show an obvious effect on the overall sealing and healing capacity of the seal at early stages. The construction and installation of the field demonstration SS/SH liner were carried out in the same way as for a soil cement liner. The quality of the liner was ensured by the enforcement of quality analysis/quality control procedures during installation. A single sealed ring infiltration test was performed on the field demonstration liner 36 days after the installation was completed. The measurement of water infiltration rate indicated that the liner healed after it was fractured. However, the long-term sealing and healing capacity needs to be further investigated.

In vivo and ex vivo measurement of polyethylene wear in total hip arthroplasty: comparison of measurements using a CT algorithm, a coordinate-measuring machine, and a micrometer.

PubMed

Goldvasser, Dov; Hansen, Viktor J; Noz, Marilyn E; Maguire, Gerald Q; Zeleznik, Michael P; Olivecrona, Henrik; Bragdon, Charles R; Weidenhielm, Lars; Malchau, Henrik

2014-06-01

Determination of the amount of wear in a polyethylene liner following total hip arthroplasty (THA) is important for both the clinical care of individual patients and the development of new types of liners. We measured in vivo wear of the polyethylene liner using computed tomography (CT) (obtained in the course of regular clinical care) and compared it to coordinate-measuring machine (CMM) readings. Also, changes in liner thickness of the same retrieved polyethylene liner were measured using a micrometer, and were compared to CT and CMM measurements. The distance between the centers of the acetabular cup and femoral head component was measured in 3D CT, using a semi-automatic analysis method. CMM readings were performed on each acetabular liner and data were analyzed using 3D computer-aided design software. Micrometer readings compared the thickest and thinnest regions of the liner. We analyzed 10 THA CTs and retrievals that met minimal requirements for CT slice thickness and explanted cup condition. RESULTS - For the 10 cups, the mean difference between the CT readings and the CMM readings was -0.09 (-0.38 to 0.20) mm. This difference was not statistically significant (p = 0.6). Between CT and micrometer, the mean difference was 0.11 (-0.33 to 0.55) mm. This difference was not statistically significant (p = 0.6). INTERPRETATION - Our results show that CT imaging is ready to be used as a tool in clinical wear measurement of polyethylene liners used in THA.

High Thermal Conductivity NARloy-Z-Diamond Composite Liner for Advanced Rocket Engines

NASA Technical Reports Server (NTRS)

Bhat, Biliyar; Greene, Sandra

2015-01-01

NARloy-Z (Cu-3Ag-0.5Zr) alloy is state-of-the-art combustion chamber liner material used in liquid propulsion engines such as the RS-68 and RS-25. The performance of future liquid propulsion systems can be improved significantly by increasing the heat transfer through the combustion chamber liner. Prior work1 done at NASA Marshall Space Flight Center (MSFC) has shown that the thermal conductivity of NARloy-Z alloy can be improved significantly by embedding high thermal conductivity diamond particles in the alloy matrix to form NARloy-Z-diamond composite (fig. 1). NARloy-Z-diamond composite containing 40vol% diamond showed 69% higher thermal conductivity than NARloy-Z. It is 24% lighter than NARloy-Z and hence the density normalized thermal conductivity is 120% better. These attributes will improve the performance and life of the advanced rocket engines significantly. The research work consists of (a) developing design properties (thermal and mechanical) of NARloy-Z-D composite, (b) fabrication of net shape subscale combustion chamber liner, and (c) hot-fire testing of the liner to test performance. Initially, NARloy-Z-D composite slabs were made using the Field Assisted Sintering Technology (FAST) for the purpose of determining design properties. In the next step, a cylindrical shape was fabricated to demonstrate feasibility (fig. 3). The liner consists of six cylinders which are sintered separately and then stacked and diffusion bonded to make the liner (fig. 4). The liner will be heat treated, finish-machined, and assembled into a combustion chamber and hot-fire tested in the MSFC test facility (TF 115) to determine perform.

Interface toughness of a zirconia-veneer system and the effect of a liner application.

PubMed

Wang, Gaoqi; Zhang, Song; Bian, Cuirong; Kong, Hui

2014-09-01

Chipping of veneering porcelain and delamination of a zirconia-veneer interface are 2 common clinical failure modes for zirconia-based restorations and may be partially due to weak interface bonding. The effect of liner on the bond strength of the interface has not been clearly identified. The purpose of the research was to evaluate the interface toughness between the zirconia core and veneering porcelain by means of a fracture mechanics test and to assess the effect of liner on the bond strength of the interface. Thirty bilayered beam-shape specimens were prepared and divided into 2 groups according to liner application. The specimens in each group were subdivided into 3 subgroups in accordance with 3 different veneer thicknesses. A fracture mechanics test was used on each specimen, and the energy release rate, G, and phase angle, ψ, were calculated according to the experimental results. A video microscope was used to monitor the crack propagation, and a scanning electron microscope was used to identify the fracture mode after testing. Two-way ANOVA and the Tukey honestly significant difference test were performed to analyze the experimental data (α=.05) . At each phase angle, the interfaces without a liner had higher mean G values than the interfaces with a liner. Both of the interfaces showed mixed failure mode with thin layers of a veneer or a liner that remained on the zirconia surfaces. Liner application before veneering reduced the interface toughness between zirconia and veneer. Copyright © 2014 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

30 CFR 250.425 - What are the requirements for pressure testing liners?

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...) You must test each drilling liner (and liner-lap) to a pressure at least equal to the anticipated... drilling or other down-hole operations until you obtain a satisfactory pressure test. If the pressure...

40 CFR 265.301 - Design and operating requirements.

Code of Federal Regulations, 2012 CFR

2012-07-01

... landfill unit must install two or more liners and a leachate collection and removal system above and between such liners, and operate the leachate collection and removal system, in accordance with § 264.301... case of any unit in which the liner and leachate collection system has been installed pursuant to the...

40 CFR 265.301 - Design and operating requirements.

Code of Federal Regulations, 2011 CFR

2011-07-01

... landfill unit must install two or more liners and a leachate collection and removal system above and between such liners, and operate the leachate collection and removal system, in accordance with § 264.301... case of any unit in which the liner and leachate collection system has been installed pursuant to the...

40 CFR 265.301 - Design and operating requirements.

Code of Federal Regulations, 2013 CFR

2013-07-01

... landfill unit must install two or more liners and a leachate collection and removal system above and between such liners, and operate the leachate collection and removal system, in accordance with § 264.301... case of any unit in which the liner and leachate collection system has been installed pursuant to the...

40 CFR 265.301 - Design and operating requirements.

Code of Federal Regulations, 2014 CFR

2014-07-01

... landfill unit must install two or more liners and a leachate collection and removal system above and between such liners, and operate the leachate collection and removal system, in accordance with § 264.301... case of any unit in which the liner and leachate collection system has been installed pursuant to the...

40 CFR 265.301 - Design and operating requirements.

Code of Federal Regulations, 2010 CFR

2010-07-01

... landfill unit must install two or more liners and a leachate collection and removal system above and between such liners, and operate the leachate collection and removal system, in accordance with § 264.301... case of any unit in which the liner and leachate collection system has been installed pursuant to the...

CALUTRON

DOEpatents

Brobeck, W.M.; Lofgren, E.J.; Thornton, R.L.

1959-06-01

A calutron improved in liner and capacity is offered. The liner is a hollow insulated structure at high negative potential with respect to the vessel. The liner has delimiting vanes to prevent ions from one beam scattering into the receiver from another beam. The double beam-double receiver feature is thus made possible, increasing the capacity of the calutron. (T.R.H.)

78 FR 15870 - Airworthiness Directives; Bombardier, Inc. Airplanes

Federal Register 2010, 2011, 2012, 2013, 2014

2013-03-13

... the old style liners (paragraph (i) of the NPRM (77 FR 42457, July 19, 2012)) from the effective date... needs to have the flexibility to install the old style liners when replacing any that might become damaged. We agree to change the date of the prohibition of the installation of the old style liners for...

LINER FOR EXTRUSION BILLET CONTAINERS

DTIC Science & Technology

Rokide-process alumina and zirconia coatings and a Udimet 700 superalloy liner were evaluated by extrusion of 3 1/2-in. billets of Inconel 713C...One coating did with stand extrusion at 3450 F without apparent wear. The Udimet 700 liner did not show wear at 2000 F, but did react with the TZM

Autofrettage to Counteract Coefficient of Thermal Expansion Mismatch in Cryogenic Pressurized Pipes with Metallic Liners

NASA Technical Reports Server (NTRS)

Wen, Ed; Barbero, Ever; Tygielski, Phlip; Turner, James E. (Technical Monitor)

2001-01-01

Composite feedlines with metal liners have the potential to reduce weight/cost while providing the same level of permeation resistance and material compatibility of all-metal feedlines carrying cryogenic propellants in spacecraft. The major technical challenges are the large difference in Coefficient of Thermal Expansion between the liner and the composite, and the manufacturing method required to make a very thin liner with the required strength and dimensional tolerance. This study investigates the use of autofrettage (compressive preload) to counteract Coefficient of Thermal Expansion when pre-pressurization procedures cannot be used to solve this problem. Promising materials (aluminum 2219, Inconel 718, nickel, nickel alloy) and manufacturing techniques (chemical milling, electroplating) are evaluated to determine the best liner candidates. Robust, autofrettaged feedlines with a low Coefficient of Thermal Expansion liner (Inconel 718 or nickel alloy) are shown to successfully counteract mismatch at LOX temperature. A new concept, autofrettage by temperature, is introduced for high Coefficient of Thermal Expansion materials (aluminum and pure nickel) where pressure cannot be used to add compressive preload.

The electro-thermal stability of tantalum relative to aluminum and titanium in cylindrical liner ablation experiments at 550 kA

NASA Astrophysics Data System (ADS)

Steiner, Adam M.; Campbell, Paul C.; Yager-Elorriaga, David A.; Cochrane, Kyle R.; Mattsson, Thomas R.; Jordan, Nicholas M.; McBride, Ryan D.; Lau, Y. Y.; Gilgenbach, Ronald M.

2018-03-01

Presented are the results from the liner ablation experiments conducted at 550 kA on the Michigan Accelerator for Inductive Z-Pinch Experiments. These experiments were performed to evaluate a hypothesis that the electrothermal instability (ETI) is responsible for the seeding of magnetohydrodynamic instabilities and that the cumulative growth of ETI is primarily dependent on the material-specific ratio of critical temperature to melting temperature. This ratio is lower in refractory metals (e.g., tantalum) than in non-refractory metals (e.g., aluminum or titanium). The experimental observations presented herein reveal that the plasma-vacuum interface is remarkably stable in tantalum liner ablations. This stability is particularly evident when contrasted with the observations from aluminum and titanium experiments. These results are important to various programs in pulsed-power-driven plasma physics that depend on liner implosion stability. Examples include the magnetized liner inertial fusion (MagLIF) program and the cylindrical dynamic material properties program at Sandia National Laboratories, where liner experiments are conducted on the 27-MA Z facility.

Demonstration of a wireless, self-powered, electroacoustic liner system.

PubMed

Phipps, Alex; Liu, Fei; Cattafesta, Louis; Sheplak, Mark; Nishida, Toshikazu

2009-02-01

This paper demonstrates the system operation of a self-powered active liner for the suppression of aircraft engine noise. The fundamental element of the active liner system is an electromechanical Helmholtz resonator (EMHR), which consists of a Helmholtz resonator with one of its rigid walls replaced with a circular piezoceramic composite plate. For this system demonstration, two EMHR elements are used, one for acoustic impedance tuning and one for energy harvesting. The EMHR used for acoustic impedance tuning is shunted with a variable resistive load, while the EMHR used for energy harvesting is shunted to a flyback power converter and storage element. The desired acoustic impedance conditions are determined externally, and wirelessly transmitted to the liner system. The power for the receiver and the impedance tuning circuitry in the liner are supplied by the harvested energy. Tuning of the active liner is demonstrated at three different sound pressure levels (148, 151, and 153 dB) in order to show the robustness of the energy harvesting and storage system. An acoustic tuning range of approximately 200 Hz is demonstrated for each of the three available power levels.

A User''s Guide to the Zwikker-Kosten Transmission Line Code (ZKTL)

NASA Technical Reports Server (NTRS)

Kelly, J. J.; Abu-Khajeel, H.

1997-01-01

This user's guide documents updates to the Zwikker-Kosten Transmission Line Code (ZKTL). This code was developed for analyzing new liner concepts developed to provide increased sound absorption. Contiguous arrays of multi-degree-of-freedom (MDOF) liner elements serve as the model for these liner configurations, and Zwikker and Kosten's theory of sound propagation in channels is used to predict the surface impedance. Transmission matrices for the various liner elements incorporate both analytical and semi-empirical methods. This allows standard matrix techniques to be employed in the code to systematically calculate the composite impedance due to the individual liner elements. The ZKTL code consists of four independent subroutines: 1. Single channel impedance calculation - linear version (SCIC) 2. Single channel impedance calculation - nonlinear version (SCICNL) 3. Multi-channel, multi-segment, multi-layer impedance calculation - linear version (MCMSML) 4. Multi-channel, multi-segment, multi-layer impedance calculation - nonlinear version (MCMSMLNL) Detailed examples, comments, and explanations for each liner impedance computation module are included. Also contained in the guide are depictions of the interactive execution, input files and output files.

Liner-less Tanks for Space Application - Design and Manufacturing Considerations

NASA Technical Reports Server (NTRS)

Jones, Brian H.; Li, Min-Chung

2003-01-01

Composite pressure vessels, used extensively for gas and fuel containment in space vehicles, are generally constructed with a metallic liner, while the fiber reinforcement carries the major portion of the pressure-induced load. The design is dominated by the liner s low strain at yield since the reinforcing fibers cannot operate at their potential load-bearing capability without resorting to pre-stressing (or autofrettaging). An ultra high-efficiency pressure vessel, which operates at the optimum strain capability of the fibers, can be potentially achieved with a liner-less construction. This paper discusses the design and manufacturing challenges to be overcome in the development of such a pressure vessel. These include: (1) gas/liquid containment and permeation, (2) design and structural analysis, and (3) manufacturing process development. The paper also presents the development and validation tests on a liner-less pressure vessel developed by Kaiser Compositek Inc. (KCI). It should be noted that KCI s liner-less tank exhibits a highly controlled leak-before-burst mode. This feature results in a structure having the highest level of safety.

Micro- and Macro-Fluid Dynamics and Acoustics of Resonant Liners

NASA Technical Reports Server (NTRS)

Tam, Christopher K. W.; Watson, Willie (Technical Monitor)

2002-01-01

The objectives of this project are to perform direct numerical simulation of the micro-fluid and acoustic fields of a resonant acoustic liner and to investigate the physical processes by which incident sound waves are damped by the acoustic liner. We would like to report that our research work and results have fulfilled both objectives of the grant. The following is a summary of the important accomplishments: (1) Two dimensional direct numerical simulation of the flow and acoustic field around the cavity of resonant liner were successfully carried out; (2) The simulations of (1) were extended to include a laminar grazing flow; (3) The numerical simulations provided strong evidence that there are two principal mechanisms by which a resonant liner damps out an incident acoustic wave; (4) A validation test was performed by comparing the computed dissipation coefficients (not impedance) with impedance tube measurements done at GTRI; and (5) Some resources of this grant were used to support the development of new CAA methods. (Our work on numerical simulation of acoustic liners has benefited by the availability of these improved methods).

Transition duct system with metal liners for delivering hot-temperature gases in a combustion turbine engine

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

Wiebe, David J.

A transition duct system (10) for delivering hot-temperature gases from a plurality of combustors in a combustion turbine engine is provided. The system includes an exit piece (16) for each combustor. The exit piece may include a straight path segment (26) and an arcuate connecting segment (36). A respective straight metal liner (92) and an arcuate metal liner (94) may be each inwardly disposed onto a metal outer shell (38) along the straight path segment and the arcuate connecting segment (36) of the exit piece. Structural arrangements are provided to securely attach the respective liners in the presence of substantialmore » flow path pressurization. Cost-effective serviceability of the transition duct systems is realizable since the liners can be readily removed and replaced as needed.« less

Combustor assembly in a gas turbine engine

DOEpatents

Wiebe, David J; Fox, Timothy A

2015-04-28

A combustor assembly in a gas turbine engine includes a combustor device, a fuel injection system, a transition duct, and an intermediate duct. The combustor device includes a flow sleeve for receiving pressurized air and a liner surrounded by the flow sleeve. The fuel injection system provides fuel to be mixed with the pressurized air and ignited in the liner to create combustion products. The intermediate duct is disposed between the liner and the transition duct so as to define a path for the combustion products to flow from the liner to the transition duct. The intermediate duct is associated with the liner such that movement may occur therebetween, and the intermediate duct is associated with the transition duct such that movement may occur therebetween. The flow sleeve includes structure that defines an axial stop for limiting axial movement of the intermediate duct.

Development of Lead Free Energy Absorber for Space Shuttle Blast Container

NASA Technical Reports Server (NTRS)

Ingram, T.; Balles, D.; Schricker, A.; Novak, H.

1998-01-01

The Space Shuttle vehicle (SSV) is connected to the mobile launch platform (MLP) by four aft skirt hold down studs on each solid rocket booster (SRB). Prior to lift-off, the frangible nuts inside the aft skirt blast containers (BC) are severed into two nut halves by two pyrotechnic booster cartridges. This action releases the SSV and allows the hold down studs to eject through the aft skirt bore and then down into the MLP. USBI has been tasked to upgrade the BC for two specific reasons; 1. to eliminate lead for environmental concerns, and 2. to reduce the chance of nut recontact with the holddown stud. Nut recontact with the stud has been identified as a likely contributor to stud hangups. This upgrade will replace the lead liner with an aluminum foam material. The aluminum foam used as a energy absorber is a proven design in many other aerospace/defense applications. Additional benefits of using the open cell, energy absorbent aluminum foam in place of the solid lead liner are: A. Lead handling/ exposure, and possible contamination, along with hazardous waste disposal will be eliminated; B. Approximately 200 lbs. weight savings will be contributed to each Space Shuttle flight by using aluminum foam over lead; C. The new aluminum liner is designed to catch all shrapnel from frangible nuts thus virtually eliminating chance of foreign object debris (FOD) exiting the HDP, and causing potential damage to the vehicle; D. Potential of using the lighter aluminum liner over lead, allows for easier assembly and disassembly of blast container elements, also allowing for improvements in safety, operator handling, and efficiency of operations. Six BC firing tests will be required to determine if the new liner material will perform in a way to decrease the chance of stud hangups and enhance the ability of the BC to retain blast debris. Testing will be performed at the Kennedy Space Center (KSC) facility known as the Launch Equipment Test Facility (LETF), and will simulate the SRB hold- down post, with actual BC hardware and pyrotechnics assembled, and then test fired. Initial testing was performed in 1997 using a frangible nut in a static drop test over lead and aluminum foam sheet materials. The aluminum foam showed a dramatic improvement of energy absorption over the lead liner material. Proof-of-Principle testing at the KSC-LETF commenced in May, 1998, and is expected to be completed by June, 1998.

Integrated High Payoff Rocket Propulsion Technology (IHPRPT) SiC Recession Model

NASA Technical Reports Server (NTRS)

Opila, E. J.

2009-01-01

SiC stability and recession rates were modeled in hydrogen/oxygen combustion environments for the Integrated High Payoff Rocket Propulsion Technology (IHPRPT) program. The IHPRPT program is a government and industry program to improve U.S. rocket propulsion systems. Within this program SiC-based ceramic matrix composites are being considered for transpiration cooled injector faceplates or rocket engine thrust chamber liners. Material testing under conditions representative of these environments was conducted at the NASA Glenn Research Center, Cell 22. For the study described herein, SiC degradation was modeled under these Cell 22 test conditions for comparison to actual test results: molar mixture ratio, MR (O2:H2) = 6, material temperatures to 1700 C, combustion gas pressures between 0.34 and 2.10 atm, and gas velocities between 8,000 and 12,000 fps. Recession was calculated assuming rates were controlled by volatility of thermally grown silica limited by gas boundary layer transport. Assumptions for use of this model were explored, including the presence of silica on the SiC surface, laminar gas boundary layer limited volatility, and accuracy of thermochemical data for volatile Si-O-H species. Recession rates were calculated as a function of temperature. It was found that at 1700 C, the highest temperature considered, the calculated recession rates were negligible, about 200 m/h, relative to the expected lifetime of the material. Results compared favorably to testing observations. Other mechanisms contributing to SiC recession are briefly described including consumption of underlying carbon and pitting. A simple expression for liquid flow on the material surface was developed from a one-dimensional treatment of the Navier-Stokes Equation. This relationship is useful to determine under which conditions glassy coatings or thermally grown silica would flow on the material surface, removing protective layers by shear forces. The velocity of liquid flow was found to depend on the gas velocity, the viscosity of gas and liquid, as well as the thickness of the gas boundary layer and the liquid layer. Calculated flow rates of a borosilicate glass coating compared well to flow rates observed for this coating tested on a SiC panel in Cell 22.

High temperature lined conduits, elbows and tees

DOEpatents

De Feo, Angelo; Drewniany, Edward

1982-01-01

A high temperature lined conduit comprising, a liner, a flexible insulating refractory blanket around and in contact with the liner, a pipe member around the blanket and spaced therefrom, and castable rigid refractory material between the pipe member and the blanket. Anchors are connected to the inside diameter of the pipe and extend into the castable material. The liner includes male and female slip joint ends for permitting thermal expansion of the liner with respect to the castable material and the pipe member. Elbows and tees of the lined conduit comprise an elbow liner wrapped with insulating refractory blanket material around which is disposed a spaced elbow pipe member with castable refractory material between the blanket material and the elbow pipe member. A reinforcing band is connected to the elbow liner at an intermediate location thereon from which extend a plurality of hollow tubes or pins which extend into the castable material to anchor the lined elbow and permit thermal expansion. A method of fabricating the high temperature lined conduit, elbows and tees is also disclosed which utilizes a polyethylene layer over the refractory blanket after it has been compressed to maintain the refractory blanket in a compressed condition until the castable material is in place. Hot gases are then directed through the interior of the liner for evaporating the polyethylene and setting the castable material which permits the compressed blanket to come into close contact with the castable material.

Optimization of Tape Winding Process Parameters to Enhance the Performance of Solid Rocket Nozzle Throat Back Up Liners using Taguchi's Robust Design Methodology

NASA Astrophysics Data System (ADS)

Nath, Nayani Kishore

2017-08-01

The throat back up liners is used to protect the nozzle structural members from the severe thermal environment in solid rocket nozzles. The throat back up liners is made with E-glass phenolic prepregs by tape winding process. The objective of this work is to demonstrate the optimization of process parameters of tape winding process to achieve better insulative resistance using Taguchi's robust design methodology. In this method four control factors machine speed, roller pressure, tape tension, tape temperature that were investigated for the tape winding process. The presented work was to study the cogency and acceptability of Taguchi's methodology in manufacturing of throat back up liners. The quality characteristic identified was Back wall temperature. Experiments carried out using L 9 ' (34) orthogonal array with three levels of four different control factors. The test results were analyzed using smaller the better criteria for Signal to Noise ratio in order to optimize the process. The experimental results were analyzed conformed and successfully used to achieve the minimum back wall temperature of the throat back up liners. The enhancement in performance of the throat back up liners was observed by carrying out the oxy-acetylene tests. The influence of back wall temperature on the performance of throat back up liners was verified by ground firing test.

Improved Broadband Liner Optimization Applied to the Advanced Noise Control Fan

NASA Technical Reports Server (NTRS)

Nark, Douglas M.; Jones, Michael G.; Sutliff, Daniel L.; Ayle, Earl; Ichihashi, Fumitaka

2014-01-01

The broadband component of fan noise has grown in relevance with the utilization of increased bypass ratio and advanced fan designs. Thus, while the attenuation of fan tones remains paramount, the ability to simultaneously reduce broadband fan noise levels has become more desirable. This paper describes improvements to a previously established broadband acoustic liner optimization process using the Advanced Noise Control Fan rig as a demonstrator. Specifically, in-duct attenuation predictions with a statistical source model are used to obtain optimum impedance spectra over the conditions of interest. The predicted optimum impedance information is then used with acoustic liner modeling tools to design liners aimed at producing impedance spectra that most closely match the predicted optimum values. Design selection is based on an acceptance criterion that provides the ability to apply increased weighting to specific frequencies and/or operating conditions. Constant-depth, double-degree of freedom and variable-depth, multi-degree of freedom designs are carried through design, fabrication, and testing to validate the efficacy of the design process. Results illustrate the value of the design process in concurrently evaluating the relative costs/benefits of these liner designs. This study also provides an application for demonstrating the integrated use of duct acoustic propagation/radiation and liner modeling tools in the design and evaluation of novel broadband liner concepts for complex engine configurations.

Credit PSR. View looks west southwest (238°) at the north ...

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

Credit PSR. View looks west southwest (238°) at the north and east elevations of the liner lab. Solid rocket motor casings receive specially formulated rubber insulating liners that protect the casings from the heat generated by burning solid motors - Jet Propulsion Laboratory Edwards Facility, Liner Laboratory, Edwards Air Force Base, Boron, Kern County, CA

Conceptual Inflatable Fabric Structures for Protective Crew Quarters Systems in Space Vehicles and Space Habitat Structures

DTIC Science & Technology

2015-11-30

Membrane Liner FEA Model ........................................................15 Rectangular PCQS with Embedded Air Beams FEA Model...2 2 Component Air Volumes of the Rectangular PCQS Concept with Inner Membrane Liner ...GCR Galactic cosmic rays or radiation HPF High-performance fibers IML Inner membrane liner K Degree Kelvin LaRC Langley Research Center m Mass

Recyclability of mixed office waste papers containing pressure sensitive adhesives and silicone release liners

Treesearch

Julie Hess; Roberta Sena-Gomes; Lisa Davie; Marguerite Sykes

2001-01-01

Increased use of pressure sensitive adhesives for labels and stamps has introduced another contaminant into the office paper stream: silicone- coated release liners. This study examines methods and conditions for removal of contaminants, including these liners, from a typical batch of discarded office papers. Removal of contaminants contained in the furnish were...

Evaluation of the head-helmet sliding properties in an impact test.

PubMed

Trotta, Antonia; Ní Annaidh, Aisling; Burek, Roy Owen; Pelgrims, Bart; Ivens, Jan

2018-05-18

The scalp plays a crucial role in head impact biomechanics, being the first tissue involved in the impact and providing a sliding interface between the impactor and/or helmet and the skull. It is important to understand both the scalp-skull and the scalp-helmet sliding in order to determine the head response due to an impact. However, experimental data on the sliding properties of the scalp is lacking. The aim of this work was to identify the sliding properties of the scalp using cadaver heads, in terms of scalp-skull and scalp-liner (internal liner of the helmet) friction and to compare these values with that of widely used artificial headforms (HIII and magnesium EN960). The effect of the hair, the direction of sliding, the speed of the test and the normal load were considered. The experiments revealed that the sliding behaviour of the scalp under impact loading is characterised by three main phases: (1) the low friction sliding of the scalp over the skull (scalp-skull friction), (2) the tensioning effect of the scalp and (3) the sliding of the liner fabric over the scalp (scalp-liner friction). Results showed that the scalp-skull coefficient of friction (COF) is very low (0.06 ± 0.048), whereas the scalp-liner COF is 0.29 ± 0.07. The scalp-liner COF is statistically different from the value of the HIII-liner (0.75 ± 0.06) and the magnesium EN960-liner (0.16 ± 0.026). These data will lead to the improvement of current headforms for head impact standard tests, ultimately leading to more realistic head impact simulations and the optimization of helmet designs. Copyright © 2018 Elsevier Ltd. All rights reserved.

Report on Recent Upgrades to the Curved Duct Test Rig at NASA Langley Research Center

NASA Technical Reports Server (NTRS)

Gerhold, Carl H.; Brown, Martha C.; Jones, Michael G.; Howerton, Brian M.

2011-01-01

The Curved Duct Test Rig (CDTR) is an experimental facility that is designed to assess the acoustic and aerodynamic performance of aircraft engine nacelle liners in close to full scale. The test section is between 25% and 100% of the scale of aft bypass ducts of aircraft engines ranging in size from business jet to large commercial passenger jet. The CDTR has been relocated and now shares space with the Grazing Flow Impedance Tube in the Liner Technology Facility at NASA Langley Research Center. As a result of the relocation, research air is supplied to the CDTR from a 50,000 cfm centrifugal fan. This new air supply enables testing of acoustic liner samples at up to Mach 0.500. This paper documents experiments and analysis on a baseline liner sample, which the authors had analyzed and reported on prior to the move to the new facility. In the present paper, the experimental results are compared to those obtained previously in order to ensure continuity of the experimental capability. Experiments that take advantage of the facility s expanded capabilities are also reported. Data analysis features that enhance understanding of the physical properties of liner performance are introduced. The liner attenuation is shown to depend on the mode that is incident on the liner test section. The relevant parameter is the mode cut-on ratio, which determines the angle at which the sound wave is incident on the liner surface. The scattering of energy from the incident mode into higher order, less attenuated modes is demonstrated. The configuration of the acoustic treatment, in this case lined on one surface and hard wall on the opposite surface, is shown to affect the mode energy redistribution.

A review of bias flow liners for acoustic damping in gas turbine combustors

NASA Astrophysics Data System (ADS)

Lahiri, C.; Bake, F.

2017-07-01

The optimized design of bias flow liner is a key element for the development of low emission combustion systems in modern gas turbines and aero-engines. The research of bias flow liners has a fairly long history concerning both the parameter dependencies as well as the methods to model the acoustic behaviour of bias flow liners under the variety of different bias and grazing flow conditions. In order to establish an overview over the state of the art, this paper provides a comprehensive review about the published research on bias flow liners and modelling approaches with an extensive study of the most relevant parameters determining the acoustic behaviour of these liners. The paper starts with a historical description of available investigations aiming on the characterization of the bias flow absorption principle. This chronological compendium is extended by the recent and ongoing developments in this field. In a next step the fundamental acoustic property of bias flow liner in terms of the wall impedance is introduced and the different derivations and formulations of this impedance yielding the different published model descriptions are explained and compared. Finally, a parametric study reveals the most relevant parameters for the acoustic damping behaviour of bias flow liners and how this is reflected by the various model representations. Although the general trend of the investigated acoustic behaviour is captured by the different models fairly well for a certain range of parameters, in the transition region between the resonance dominated and the purely bias flow related regime all models lack the correct damping prediction. This seems to be connected to the proper implementation of the reactance as a function of bias flow Mach number.

Incidence of Ceramic Liner Malseating After Ceramic-on-Ceramic Total Hip Arthroplasty Associated With Osteolysis: A 5- to 15-Year Follow-Up Study.

PubMed

Higuchi, Yoshitoshi; Hasegawa, Yukiharu; Komatsu, Daigo; Seki, Taisuke; Ishiguro, Naoki

2017-05-01

The aim of our study was to evaluate the clinical and radiographic outcomes of malseating of the acetabular liner in ceramic-on-ceramic total hip arthroplasty (THA). Outcomes for 160 ceramic-on-ceramic THAs, contributed by 116 women and 39 men, were evaluated. Clinical and radiographic measurements were obtained over a 5- to 15-year follow-up for analysis. Liner malseating was identified in 20% of cases. Outcomes for 32 cases with liner malseating (group A) were compared to outcomes for 128 joints with correct liner seating (group B). The Harris hip score at the last follow-up was 90.1 for group A and 89.6 for group B. Osteolysis was identified in 5 cases in group A (15.6%), compared to 3 cases in group B (P < .001). No significant between-group differences were identified with regard to ceramic fracture, audible squeaking, loosening of components, and revision THA. The mean annual liner wear rate was comparable between groups, 0.0045 mm/y for group A and 0.0039 mm/y for group B. The 10-year Kaplan-Meier survivorship, based on an end point of revision THA, was 100% for group A and 99.0% for group B. Over a moderate-length follow-up of 5-15 years, malseating of the acetabular liner was not associated with negative clinical outcomes or THA survivorship. Malseating did increase the incidence of osteolysis, a risk factor for adverse effects. Long-term follow-up studies are needed to fully quantify the effects of malseating of the acetabular liner. Copyright © 2016 Elsevier Inc. All rights reserved.

The effect of denture base surface pretreatments on bond strengths of two long term resilient liners

PubMed Central

Parkhedkar, Rambhau

2011-01-01

PURPOSE Purpose of this study was to evaluate effect of two surface treatments, sandblasting and monomer treatment, on tensile bond strength between two long term resilient liners and poly (methyl methacrylate) denture base resin. MATERIALS AND METHODS Two resilient liners Super-Soft and Molloplast-B were selected.Sixty acrylic resin (Trevalon) specimens with cross sectional area of 10×10 mm were prepared and divided into two groups of 30 specimens each. Each group was surface treated (n = 10) by sandblasting (250 µ alumina particles), monomer treatment (for 180 sec) and control (no surface treatment). Resilient liners were processed between 2 poly(methyl methacrylate) surfaces, in the dimensions of 10×10×3 mm. Tensile strength was determined with Instron Universal testing machine, at a crosshead speed of 5 mm/min; and the modes of failure (adhesive, cohesive or mixed) were recorded. The data were analyzed using one-way ANOVA, followed by Tukey HSD test (α = 0.05). RESULTS Monomer pretreatment of acrylic resin produced significantly higher bond strengths when compared to sandblasting and control for both resilient liners (P < .001). Sandblasting significantly decreased the bond strength for both the liners when compared to monomer pretreatment and control (P < .001). Mean bond strength of Super-Soft lined specimens was significantly higher than Molloplast-B in various surface treatment groups (P < .05). CONCLUSION Surface pretreatment of the acrylic resin with monomer prior to resilient liner application is an effective method to increase bond strength between the base and soft liner. Sandblasting, on the contrary, is not recommended as it weakens the bond between the two. PMID:21503188

In vivo degradation of polyethylene liners after gamma sterilization in air.

PubMed

Kurtz, Steven M; Rimnac, Clare M; Hozack, William J; Turner, Joseph; Marcolongo, Michele; Goldberg, Victor M; Kraay, Matthew J; Edidin, Avram A

2005-04-01

Ultra-high molecular weight polyethylene degrades during storage in air following gamma sterilization, but the extent of in vivo degradation remains unclear. The purpose of this study was to quantify the extent to which the mechanical properties and oxidation of conventional polyethylene acetabular liners treated with gamma sterilization in air change in vivo. Fourteen modular cementless acetabular liners were revised at an average of 10.3 years (range, 5.9 to 13.5 years) after implantation. All liners, which had been machined from GUR 415 resin, had been gamma-sterilized in air; the average shelf life was 0.3 year (range, 0.0 to 0.8 year). After removal, the components were expeditiously frozen to minimize ex vivo changes to the polyethylene prior to characterization. The average duration between freezing and testing was 0.6 year. Mechanical properties and oxidation were measured with use of the small-punch test and Fourier transform infrared spectroscopy, respectively, in the loaded and unloaded regions of the liners. There was substantial regional variation in the mechanical properties and oxidation of the retrieved liners. The ultimate load was observed to vary by >90% near the surface. On the average, the rim and the unloaded bearing showed evidence of severe oxidation near the surface after long-term in vivo aging, but these trends were not typically observed on the loaded bearing surface or near the backside of the liners. The mechanical properties of polyethylene that has been gamma-sterilized in air may decrease substantially in vivo, depending on the location in the liner. The most severe oxidation was observed at the rim, suggesting that the femoral head inhibits access of oxygen-containing body fluids to the bearing surface. This is perhaps why in vivo oxidation has not been associated with clinical performance to date.

Study of Plasma Liner Driven Magnetized Target Fusion Via Advanced Simulations

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

Samulyak, Roman V.; Brookhaven National Lab.; Parks, Paul

The feasibility of the plasma liner driven Magnetized Target Fusion (MTF) via terascale numerical simulations will be assessed. In the MTF concept, a plasma liner, formed by merging of a number (60 or more) of radial, highly supersonic plasma jets, implodes on the target in the form of two compact plasma toroids, and compresses it to conditions of the fusion ignition. By avoiding major difficulties associated with both the traditional laser driven inertial confinement fusion and solid liner driven MTF, the plasma liner driven MTF potentially provides a low-cost and fast R&D path towards the demonstration of practical fusion energy.more » High fidelity numerical simulations of full nonlinear models associated with the plasma liner MTF using state-of-art numerical algorithms and terascale computing are necessary in order to resolve uncertainties and provide guidance for future experiments. At Stony Brook University, we have developed unique computational capabilities that ideally suite the MTF problem. The FronTier code, developed in collaboration with BNL and LANL under DOE funding including SciDAC for the simulation of 3D multi-material hydro and MHD flows, has beenbenchmarked and used for fundamental and engineering problems in energy science applications. We have performed 3D simulations of converging supersonic plasma jets, their merger and the formation of the plasma liner, and a study of the corresponding oblique shock problem. We have studied the implosion of the plasma liner on the magnetized plasma target by resolving Rayleigh-Taylor instabilities in 2D and 3D and other relevant physics and estimate thermodynamic conditions of the target at the moment of maximum compression and the hydrodynamic efficiency of the method.« less

Heat pipe cooling for scramjet engines

NASA Technical Reports Server (NTRS)

Silverstein, Calvin C.

1986-01-01

Liquid metal heat pipe cooling systems have been investigated for the combustor liner and engine inlet leading edges of scramjet engines for a missile application. The combustor liner is cooled by a lithium-TZM molybdenum annular heat pipe, which incorporates a separate lithium reservoir. Heat is initially absorbed by the sensible thermal capacity of the heat pipe and liner, and subsequently by the vaporization and discharge of lithium to the atmosphere. The combustor liner temperature is maintained at 3400 F or less during steady-state cruise. The engine inlet leading edge is fabricated as a sodium-superalloy heat pipe. Cooling is accomplished by radiation of heat from the aft surface of the leading edge to the atmosphere. The leading edge temperature is limited to 1700 F or less. It is concluded that heat pipe cooling is a viable method for limiting scramjet combustor liner and engine inlet temperatures to levels at which structural integrity is greatly enhanced.

Experiment to Form and Characterize a Section of a Spherically Imploding Plasma Liner

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

Hsu, S. C.; Langendorf, S. J.; Yates, K. C.

Here, we describe an experiment to form and characterize a section of a spherically imploding plasma liner by merging six supersonic plasma jets that are launched by newly designed contoured-gap coaxial plasma guns. This experiment is a prelude to forming a fully spherical imploding plasma liner using many dozens of plasma guns, as a standoff driver for plasma-jet-driven magneto-inertial fusion. The objectives of the six-jet experiments are to assess the evolution and scalings of liner Mach number and uniformity, which are important metrics for spherically imploding plasma liners to compress magnetized target plasmas to fusion conditions. Lastly, this article describesmore » the design of the coaxial plasma guns, experimental characterization of the plasma jets, six-jet experimental setup and diagnostics, initial diagnostic data from three- and six-jet experiments, and the high-level objectives of associated numerical modeling.« less

Experiment to Form and Characterize a Section of a Spherically Imploding Plasma Liner

DOE PAGES

Hsu, S. C.; Langendorf, S. J.; Yates, K. C.; ...

2017-12-18

Here, we describe an experiment to form and characterize a section of a spherically imploding plasma liner by merging six supersonic plasma jets that are launched by newly designed contoured-gap coaxial plasma guns. This experiment is a prelude to forming a fully spherical imploding plasma liner using many dozens of plasma guns, as a standoff driver for plasma-jet-driven magneto-inertial fusion. The objectives of the six-jet experiments are to assess the evolution and scalings of liner Mach number and uniformity, which are important metrics for spherically imploding plasma liners to compress magnetized target plasmas to fusion conditions. Lastly, this article describesmore » the design of the coaxial plasma guns, experimental characterization of the plasma jets, six-jet experimental setup and diagnostics, initial diagnostic data from three- and six-jet experiments, and the high-level objectives of associated numerical modeling.« less

Drapery assembly including insulated drapery liner

DOEpatents

Cukierski, Gwendolyn

1983-01-01

A drapery assembly is disclosed for covering a framed wall opening, the assembly including drapery panels hung on a horizontal traverse rod, the rod having a pair of master slides and means for displacing the master slides between open and closed positions. A pair of insulating liner panels are positioned behind the drapery, the remote side edges of the liner panels being connected with the side portions of the opening frame, and the adjacent side edges of the liner panels being connected with a pair of vertically arranged center support members adapted for sliding movement longitudinally of a horizontal track member secured to the upper horizontal portion of the opening frame. Pivotally arranged brackets connect the center support members with the master slides of the traverse rod whereby movement of the master slides to effect opening and closing of the drapery panels effects simultaneous opening and closing of the liner panels.

Duct wall impedance control as an advanced concept for acoustic suppression enhancement. [engine noise reduction

NASA Technical Reports Server (NTRS)

Dean, P. D.

1978-01-01

A systems concept procedure is described for the optimization of acoustic duct liner design for both uniform and multisegment types. The concept was implemented by the use of a double reverberant chamber flow duct facility coupled with sophisticated computer control and acoustic analysis systems. The optimization procedure for liner insertion loss was based on the concept of variable liner impedance produced by bias air flow through a multilayer, resonant cavity liner. A multiple microphone technique for in situ wall impedance measurements was used and successfully adapted to produce automated measurements for all liner configurations tested. The complete validation of the systems concept was prevented by the inability to optimize the insertion loss using bias flow induced wall impedance changes. This inability appeared to be a direct function of the presence of a higher order energy carrying modes which were not influenced significantly by the wall impedance changes.

Evaluation of two polyimides and of an improved liner retention design for self-lubricating bushings

NASA Technical Reports Server (NTRS)

Sliney, H. E.

1984-01-01

Two different polyimide polymers were studied and the effectiveness of a design feature to improve retention of the self lubricating composite liners under high load was evaluated. The basic bearing design consisted of a molded layer of chopped graphite-fiber-reinforced-polyimide (GFRP) composite bonded to the bore of a steel bushing. The friction, wear, and load carrying ability of the bushings were determined in oscillating tests at 25, 260 and 315 C at radial unit loads up to 260 MPa. Friction coefficients were typically 0.15 to 0.25. Bushings with liners containing a new partially fluorinated polymer were functional, but had a lower load capacity and higher wear rate than those containing a more conventional, high temperature polyimide. The liner retention design feature reduced the tendency of the liners to crack and work out of the contact zone under high oscillating loads.

Acoustic Liner Drag: A Parametric Study of Conventional Configurations

NASA Technical Reports Server (NTRS)

Howerton, Brian M.; Jones, Michael G.

2015-01-01

Interest in the characterization of the aerodynamic drag performance of acoustic liners has increased in the past several years. This paper details experiments in NASA Langley's Grazing Flow Impedance Tube to quantify the relative drag of several conventional perforate-over-honeycomb liner configurations. For a fixed porosity, facesheet hole diameter and cavity depth are varied to study the effect of each. These configurations are selected to span the range of conventional liner geometries used in commercial aircraft engines. Detailed static pressure and acoustic measurements are made for grazing flows up to M=0.5 at 140 dB SPL for tones between 400 and 2800 Hz. These measurements are used to calculate a resistance factor (?) for each configuration. Analysis shows a correlation between perforate hole size and the resistance factor but cavity depth seems to have little influence. Acoustic effects on liner drag are observed to be limited to the lower Mach numbers included in this investigation.

Direct numerical simulation of turbulent flow with an impedance condition

NASA Astrophysics Data System (ADS)

Olivetti, Simone; Sandberg, Richard D.; Tester, Brian J.

2015-05-01

DNS solutions for a pipe/jet configuration are re-computed with the pipe alone to investigate suppression of previously identified internal noise source(s) with an acoustic liner, using a time domain acoustic liner model developed by Tam and Auriault (AIAA Journal, 34 (1996) 913-917). Liner design parameters are chosen to achieve up to 30 dB attenuation of the broadband pressure field over the pipe length without affecting the velocity field statistics. To understand the effect of the liner on the acoustic and turbulent components of the unsteady wall pressure, an azimuthal/axial Fourier transform is applied and the acoustic and turbulent wavenumber regimes clearly identified. It is found that the spectral component occupying the turbulent wavenumber range is unaffected by the liner whereas the acoustic wavenumber components are strongly attenuated, with individual radial modes being evident as each cuts on with increasing Strouhal number.

Adaptive Back Sheet Material for Acoustic Liner Applications-ARMD Seedling Fund Phase I Final Report

NASA Technical Reports Server (NTRS)

Gerhold, Carl H.; Jones, Michael G.; Farrar, Dawnielle

2014-01-01

A recently developed piezo-electric composite film is evaluated for its usefulness in application in acoustic liners. Researchers at the NASA Langley Research Center Liner Technology Facility developed experiments to measure the electrical response of the material to acoustic excitation and the vibrational response of the material to electrical excitation. The robustness of the piezo-electric film was also assessed. The material's electrical response to acoustic excitation is found to be comparable to a commercial microphone in the range of frequencies from 500 to 3000 Hz. However, the vibrational response to electrical excitation in the frequency range of interest is an order of magnitude less than may be necessary for application to acoustic liners. Nevertheless, experimental results indicate that the potential exists for the material to produce a measurable change in the impedance spectrum of a liner. Work continues to improve the authority of the piezo-electric film.

Combustor assembly in a gas turbine engine

DOEpatents

Wiebe, David J; Fox, Timothy A

2013-02-19

A combustor assembly in a gas turbine engine. The combustor assembly includes a combustor device coupled to a main engine casing, a first fuel injection system, a transition duct, and an intermediate duct. The combustor device includes a flow sleeve for receiving pressurized air and a liner disposed radially inwardly from the flow sleeve. The first fuel injection system provides fuel that is ignited with the pressurized air creating first working gases. The intermediate duct is disposed between the liner and the transition duct and defines a path for the first working gases to flow from the liner to the transition duct. An intermediate duct inlet portion is associated with a liner outlet and allows movement between the intermediate duct and the liner. An intermediate duct outlet portion is associated with a transition duct inlet section and allows movement between the intermediate duct and the transition duct.

INTERNAL REPAIR OF PIPELINES

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

Robin Gordon; Bill Bruce; Ian Harris

2004-12-31

The two broad categories of fiber-reinforced composite liner repair and deposited weld metal repair technologies were reviewed and evaluated for potential application for internal repair of gas transmission pipelines. Both are used to some extent for other applications and could be further developed for internal, local, structural repair of gas transmission pipelines. Principal conclusions from a survey of natural gas transmission industry pipeline operators can be summarized in terms of the following performance requirements for internal repair: (1) Use of internal repair is most attractive for river crossings, under other bodies of water, in difficult soil conditions, under highways, undermore » congested intersections, and under railway crossings. (2) Internal pipe repair offers a strong potential advantage to the high cost of horizontal direct drilling when a new bore must be created to solve a leak or other problem. (3) Typical travel distances can be divided into three distinct groups: up to 305 m (1,000 ft.); between 305 m and 610 m (1,000 ft. and 2,000 ft.); and beyond 914 m (3,000 ft.). All three groups require pig-based systems. A despooled umbilical system would suffice for the first two groups which represents 81% of survey respondents. The third group would require an onboard self-contained power unit for propulsion and welding/liner repair energy needs. (4) The most common size range for 80% to 90% of operators surveyed is 508 mm (20 in.) to 762 mm (30 in.), with 95% using 558.8 mm (22 in.) pipe. Evaluation trials were conducted on pipe sections with simulated corrosion damage repaired with glass fiber-reinforced composite liners, carbon fiber-reinforced composite liners, and weld deposition. Additional un-repaired pipe sections were evaluated in the virgin condition and with simulated damage. Hydrostatic failure pressures for pipe sections repaired with glass fiber-reinforced composite liner were only marginally greater than that of pipe sections without liners, indicating that this type of liner is only marginally effective at restoring the pressure containing capabilities of pipelines. Failure pressures for larger diameter pipe repaired with a semi-circular patch of carbon fiber-reinforced composite lines were also marginally greater than that of a pipe section with un-repaired simulated damage without a liner. These results indicate that fiber reinforced composite liners have the potential to increase the burst pressure of pipe sections with external damage Carbon fiber based liners are viewed as more promising than glass fiber based liners because of the potential for more closely matching the mechanical properties of steel. Pipe repaired with weld deposition failed at pressures lower than that of un-repaired pipe in both the virgin and damaged conditions, indicating that this repair technology is less effective at restoring the pressure containing capability of pipe than a carbon fiber-reinforced liner repair. Physical testing indicates that carbon fiber-reinforced liner repair is the most promising technology evaluated to-date. The first round of optimization and validation activities for carbon-fiber repairs are complete. Development of a comprehensive test plan for this process is recommended for use in the field trial portion of this program.« less

INTERNAL REPAIR OF PIPELINES

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

Robin Gordon; Bill Bruce; Ian Harris

2004-08-17

The two broad categories of fiber-reinforced composite liner repair and deposited weld metal repair technologies were reviewed and evaluated for potential application for internal repair of gas transmission pipelines. Both are used to some extent for other applications and could be further developed for internal, local, structural repair of gas transmission pipelines. Principal conclusions from a survey of natural gas transmission industry pipeline operators can be summarized in terms of the following performance requirements for internal repair: (1) Use of internal repair is most attractive for river crossings, under other bodies of water, in difficult soil conditions, under highways, undermore » congested intersections, and under railway. (2) Internal pipe repair offers a strong potential advantage to the high cost of horizontal direct drilling when a new bore must be created to solve a leak or other problem. (3) Typical travel distances can be divided into three distinct groups: up to 305 m (1,000 ft.); between 305 m and 610 m (1,000 ft. and 2,000 ft.); and beyond 914 m (3,000 ft.). All three groups require pig-based systems. A despooled umbilical system would suffice for the first two groups which represents 81% of survey respondents. The third group would require an onboard self-contained power unit for propulsion and welding/liner repair energy needs. (4) The most common size range for 80% to 90% of operators surveyed is 508 mm (20 in.) to 762 mm (30 in.), with 95% using 558.8 mm (22 in.) pipe. Evaluation trials were conducted on pipe sections with simulated corrosion damage repaired with glass fiber-reinforced composite liners, carbon fiber-reinforced composite liners, and weld deposition. Additional un-repaired pipe sections were evaluated in the virgin condition and with simulated damage. Hydrostatic failure pressures for pipe sections repaired with glass fiber-reinforced composite liner were only marginally greater than that of pipe sections without liners, indicating that this type of liner is only marginally effective at restoring the pressure containing capabilities of pipelines. Failure pressures for larger diameter pipe repaired with a semi-circular patch of carbon fiber-reinforced composite lines were also marginally greater than that of a pipe section with un-repaired simulated damage without a liner. These results indicate that fiber reinforced composite liners have the potential to increase the burst pressure of pipe sections with external damage Carbon fiber based liners are viewed as more promising than glass fiber based liners because of the potential for more closely matching the mechanical properties of steel. Pipe repaired with weld deposition failed at pressures lower than that of un-repaired pipe in both the virgin and damaged conditions, indicating that this repair technology is less effective at restoring the pressure containing capability of pipe than a carbon fiber-reinforced liner repair. Physical testing indicates that carbon fiber-reinforced liner repair is the most promising technology evaluated to-date. Development of a comprehensive test plan for this process is recommended for use in the field trial portion of this program.« less

The General Isothermal Oxidation Behavior of Cu-8Cr-4Nb

NASA Technical Reports Server (NTRS)

Thomas-Ogbuji, L. U.; Gray, Hugh R. (Technical Monitor)

2002-01-01

Oxidation kinetics of Cu-8Cr-4Nb was investigated by TGA (thermogravimetric) exposures between 500 and 900-C (at 25-50 C intervals) and the oxide scale morphologies examined by microscopy and micro-analysis. Because Cu-8Cr-4Nb is comprised of fine Cr2Nb precipitates in a Cu matrix, the results were interpreted by comparison with the behavior of copper (OFHC) and 'NARloy-Z' (a rival candidate material for thrust cell liner applications in advanced rocket engines) under the same conditions. While NARloy-Z and Cu exhibited identical oxidation behavior, Cu-8Cr-4Nb differed markedly in several respects: below approx. 700 C its oxidation rates were significantly lower than those of Cu; At higher temperatures its oxidation rates fell into two categories: an initial rate exceeding that of Cu, and a terminal rate comparable to that of Cu. Differences in oxide morphologies paralleled the kinetic differences at higher temperature: While NARloy-Z and Cu produced a uniform oxide scale of Cu2O inner layer and CuO outer layer, the inner (Cu2O) layer on Cu-8Cr-4Nb was stratified, with a highly porous/spongy inner stratum (responsible for the fast initial kinetics) and a dense/blocky outer stratum (corresponding to the slow terminal kinetics). Single and spinel oxides of Nb and Cr were found at the interface between the oxide scale and Cu-8Cr-4Nb substrate and it appears that these oxides were responsible for its suppressed oxidation rates at the intermediate temperatures. No difference was found between Cu-8Cr-4Nb oxidation in air and in oxygen at 1.0 atm.

The Behavior of Shaped Charges with Open-Poled Hemispherical Liners

DTIC Science & Technology

1990-11-01

Racketenpanzcrbuchse .................................. 14 8. The Japanese SAKURA Bomb .................................... 15 9 . ERF-16’s I-MeV Test...84 A- 9 . Liner and Plug Design for Rounds 4134 and 4146 ....................... 85 A-10. Liner and Plug Design for Round 4141...km/see) .......... 50 8. Cumulative Momentum and Energy (Cutoff Velocity = 3.5 km/sec) .......... 50 9 . Measured Tip Mass and Velocity

Solvent Recycling for Shipyards

DTIC Science & Technology

1993-05-01

Suvey results are included in Section 5) Survey manufacturers and compile information on available equipment and features . (Data is summarized in Section...should be placed on safety features . Important safety features include explosion-proof electricals and grounding protection, overpressure relief valves...solvent can dissolve a polymer plastic liner, or extract water from a clay liner, resulting in liner leakage. The threat is compounded by the ability

Spin-rolling, welding, and heat treatment of aluminium 2219 for Ariane 5 GAM high pressure vessel liners

NASA Astrophysics Data System (ADS)

Radtke, W.

1992-10-01

Cylindrical liners made of Al 2219 may be spinrolled if both recrystallization and metastable precipitates can be avoided during forging or preparatory heat treatment. So welding is to be limited to circumferential joints. Pore-free welds are attainable immediately after hydroxide layer removal by diamond cutting without grease application. The EB vacuum is favorable to porosity suppression. A complete heat treatment of the liner incorporating solutionizing, water quenching and ageing leads to 100 percent weld efficiency. Pressure stabilization avoids buckling. Subsequent carbon fiber winding, curing and plastic prestressing of the liner results in an efficient high pressure vessel for hydrogen service.

Development and Validation of an Interactive Liner Design and Impedance Modeling Tool

NASA Technical Reports Server (NTRS)

Howerton, Brian M.; Jones, Michael G.; Buckley, James L.

2012-01-01

The Interactive Liner Impedance Analysis and Design (ILIAD) tool is a LabVIEW-based software package used to design the composite surface impedance of a series of small-diameter quarter-wavelength resonators incorporating variable depth and sharp bends. Such structures are useful for packaging broadband acoustic liners into constrained spaces for turbofan engine noise control applications. ILIAD s graphical user interface allows the acoustic channel geometry to be drawn in the liner volume while the surface impedance and absorption coefficient calculations are updated in real-time. A one-dimensional transmission line model serves as the basis for the impedance calculation and can be applied to many liner configurations. Experimentally, tonal and broadband acoustic data were acquired in the NASA Langley Normal Incidence Tube over the frequency range of 500 to 3000 Hz at 120 and 140 dB SPL. Normalized impedance spectra were measured using the Two-Microphone Method for the various combinations of channel configurations. Comparisons between the computed and measured impedances show excellent agreement for broadband liners comprised of multiple, variable-depth channels. The software can be used to design arrays of resonators that can be packaged into complex geometries heretofore unsuitable for effective acoustic treatment.

The PLX- α project: demonstrating the viability of spherically imploding plasma liners as an MIF driver

NASA Astrophysics Data System (ADS)

Hsu, S. C.; Witherspoon, F. D.; Cassibry, J. T.; Gilmore, M.; Samulyak, R.; Stoltz, P.; the PLX-α Team

2015-11-01

Under ARPA-E's ALPHA program, the Plasma Liner Experiment-ALPHA (PLX- α) project aims to demonstrate the viability and scalability of spherically imploding plasma liners as a standoff, high-implosion-velocity magneto-inertial-fusion (MIF) driver that is potentially compatible with both low- and high- β targets. The project has three major objectives: (a) advancing existing contoured-gap coaxial-gun technology to achieve higher operational reliability/precision and better control/reproducibility of plasma-jet properties and profiles; (2) conducting ~ π / 2 -solid-angle plasma-liner experiments with 9 guns to demonstrate (along with extrapolations from modeling) that the jet-merging process leads to Mach-number degradation and liner uniformity that are acceptable for MIF; and (3) conducting 4 π experiments with up to 60 guns to demonstrate the formation of an imploding spherical plasma liner for the first time, and to provide empirical ram-pressure and uniformity scaling data for benchmarking our codes and informing us whether the scalings justify further development beyond ALPHA. This talk will provide an overview of the PLX- α project as well as key research results to date. Supported by ARPA-E's ALPHA program; original PLX construction supported by DOE Fusion Energy Sciences.

Analysis of staged Z-pinch implosion trajectories from experiments on Zebra

NASA Astrophysics Data System (ADS)

Ross, Mike P.; Conti, F.; Darling, T. W.; Ruskov, E.; Valenzuela, J.; Wessel, F. J.; Beg, F.; Narkis, J.; Rahman, H. U.

2017-10-01

The Staged Z-pinch plasma confinement concept relies on compressing an annular liner of high-Z plasma onto a target plasma column of deuterium fuel. The interface between the liner and target is stable against the Magneto-Rayleigh-Taylor Instability, which leads to effective fuel compression and makes the concept interesting as a potential fusion reactor. The liner initiates as a neutral gas puff, while the target plasma is a partially ionized (Zeff < 10 percent column ejected from a coaxial plasma gun. The Zebra pulsed power generator (1 MA peak current, 100 ns rise time) provides the discharge that ionizes the liner and drives the Z-pinch implosion. Diverse diagnostics observe the 100-300 km/s implosions including silicon diodes, photo-conducting detectors (PCDs), laser shadowgraphy, an XUV framing camera, and a visible streak camera. The imaging diagnostics track instabilities smaller than 0.1 mm, and Z-pinch diameters below 2.5 mm are seen at peak compression. This poster correlates the data from these diagnostics to elucidate implosion behavior dependencies on liner gas, liner pressure, target pressure, and applied, axial-magnetic field. Funded by the Advanced Research Projects Agency - Energy, DE-AR0000569.

Experimental Study of Magnetic Field Production and Dielectric Breakdown of Auto-Magnetizing Liners

NASA Astrophysics Data System (ADS)

Shipley, Gabriel; Awe, Thomas; Hutchinson, Trevor; Hutsel, Brian; Slutz, Stephen; Lamppa, Derek

2017-10-01

AutoMag liners premagnetize the fuel in MagLIF targets and provide enhanced x-ray diagnostic access and increased current delivery without requiring external field coils. AutoMag liners are composite liners made with discrete metallic helical conduction paths separated by insulating material. First, a low dI/dt ``foot'' current pulse (1 MA in 100 ns) premagnetizes the fuel. Next, a higher dI/dt pulse with larger induced electric field initiates breakdown on the composite liner's; surface, switching the current from helical to axial to implode the liner. Experiments on MYKONOS have tested the premagnetization and breakdown phases of AutoMag and demonstrate axial magnetic fields above 90 Tesla for a 550 kA peak current pulse. Electric fields of 17 MV/m have been generated before breakdown. AutoMag may enhance MagLIF performance by increasing the premagnetization strength significantly above 30 T, thus reducing thermal-conduction losses and mitigating anomalous diffusion of magnetic field out of hotter fuel regions, by, for example, the Nernst thermoelectric effect. This project was funded in part by Sandia's Laboratory Directed Research and Development Program (Projects No. 200169 and 195306).

Modeling of Passive Acoustic Liners from High Fidelity Numerical Simulations

NASA Astrophysics Data System (ADS)

Ferrari, Marcello do Areal Souto

Noise reduction in aviation has been an important focus of study in the last few decades. One common solution is setting up acoustic liners in the internal walls of the engines. However, measurements in the laboratory with liners are expensive and time consuming. The present work proposes a nonlinear physics-based time domain model to predict the acoustic behavior of a given liner in a defined flow condition. The parameters of the model are defined by analysis of accurate numerical solutions of the flow obtained from a high-fidelity numerical code. The length of the cavity is taken into account by using an analytical procedure to account for internal reflections in the interior of the cavity. Vortices and jets originated from internal flow separations are confirmed to be important mechanisms of sound absorption, which defines the overall efficiency of the liner. Numerical simulations at different frequency, geometry and sound pressure level are studied in detail to define the model parameters. Comparisons with high-fidelity numerical simulations show that the proposed model is accurate, robust, and can be used to define a boundary condition simulating a liner in a high-fidelity code.

Theory of formation of helical structures in a perfectly conducting, premagnetized Z-pinch liner

NASA Astrophysics Data System (ADS)

Yu, Edmund; Velikovich, Alexander; Peterson, Kyle

2014-10-01

The magnetized liner inertial fusion (MagLIF) concept uses an azimuthal magnetic field to collapse a thick metallic liner containing preheated fusion fuel. A critical component of the concept is an axial magnetic field, permeating both the fuel and surrounding liner, which reduces the compression necessary to achieve fusion conditions. Recent experiments demonstrate that a liner premagnetized with a 10 T axial field develops helical structures with a pitch significantly larger than an estimate of Bz /Bθ would suggest. The cause of the helical perturbations is still not understood. In this work, we present an analytic, linear theory in which we model the liner as a perfectly conducting metal, and study how bumps and divots on its surface redirect current flow, resulting in perturbations to B as well as j × B . We show that in the presence of axial and azimuthal magnetic field, the theory predicts divots will grow and deform at an angle determined by the magnetic field. We compare theoretical results with three dimensional, resistive MHD simulations. Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the National Nuclear Security Administration under DE-AC04-94AL85000.

Microstructural change in electroformed copper liners of shaped charges upon plastic deformation at ultra-high strain rate

NASA Astrophysics Data System (ADS)

Tian, W. H.; Hu, S. L.; Fan, A. L.; Wang, Z.

2002-01-01

Transmission electron microscopy (TEM) observations were carried out for examining the as-formed and post-deformed microstructures in a variety of electroformed copper liners of shaped charges. The deformation was carried out at an ultra-high strain rate. Specifically, the electron backscattering Kikuchi pattern (EBSP) technique was utilized to examine the micro-texture of these materials. TEM observations revealed that these electroformed copper liners of shaped charges have a grain size of about 1-3 mum, EBSP analysis demonstrated that the as-grown copper liners of shaped charges exhibit a l 10) fiber micro-texture which is parallel to the normal direction of the surface of the liners of shaped charges. Having undergone plastic deformation at ultra-high strain rate (10(7) s(-1)), the specimens which were recovered from the copper slugs were found to have grain size of the same order as that before deformation. EBSP analysis revealed that the (110) fiber texture existed in the as-formed copper liners disappears in the course of deformation. TEM examination results indicate that dynamic recovery and recrystallization play a significant role in this deformation process.

Early time studies of cylindrical liner implosions at 1 MA on COBRA

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

Atoyan, L., E-mail: la296@cornell.edu; Byvank, T., E-mail: la296@cornell.edu; Cahill, A. D., E-mail: la296@cornell.edu

Tests of the magnetized liner inertial fusion (MagLIF) concept will make use of the 27 MA Z machine at Sandia National Laboratories, Albuquerque, to implode a cylindrical metal liner to compress and heat preheated, magnetized plasma contained within it. While most pulsed power machines produce much lower currents than the Z-machine, there are issues that can still be addressed on smaller scale facilities. Recent work on the Cornell Beam Research Accelerator (COBRA) has made use of 10 mm long and 4 mm diameter metal liners having different wall thicknesses to study the initiation of plasma on the liner’s surface asmore » well as axial magnetic field compression [P.-A. Gourdain et al., Nucl. Fusion 53, 083006 (2013)]. This report presents experimental results with non-imploding liners, investigating the impact the liner’s surface structure has on initiation and ablation. Extreme ultraviolet (XUV) imaging and optical 12 frame camera imaging were used to observe and assess emission non-uniformities as they developed. Axial and side-on interferometry was used to determine the distribution of plasma near the liner surface, including the impact of non-uniformities during the plasma initiation and ablation phases of the experiments.« less

Development of Lightweight, Compact, Structurally-Integrated Acoustic Liners for Broadband Low-Frequency Noise Mitigation

NASA Astrophysics Data System (ADS)

Chambers, Andrew T.

Airborne noise with a low dominant frequency content (< 500 Hz) has detrimental effects in many applications, but is as yet beyond the scope of conventional acoustic noise mitigation techniques using liners, foams or claddings owing to mass and volume considerations. Its low evanescence contributes significantly to environmental noise pollution, and unwanted structural vibrations causing diminished efficiency, comfort, payload integrity and mission capabilities. An alternative approach using liner configurations with realistic mass and volume constraints having innovative 'folded' core geometries is investigated to ascertain its low-frequency noise absorption characteristics. In contrast to mass-driven approaches, the folded core approach relies on tailoring interactions between acoustic resonances to tune the liner's impedance to suit the dominant low-frequency content of the source. This allows to keep non-structural mass-addition to a minimum, while retaining an overall thickness comparable to conventional liners for these low-frequency liner designs. The relative acoustic performance of various candidate folded core designs is evaluated by means of a new composite metric termed the Low-Frequency Performance (LFP) factor, which is educed from the absorption coefficient spectrum obtained using Zwikker-Kosten Transmission Line (ZKTL) theory-based numerical studies. An LFP-based software tool is developed to determine optimal 3D cavity packing for a prescribed liner volume and target frequency range. ZKTL-based parametric studies on core dimensions and face sheet porosity are utilized for detailed design of test articles. Experimental verification of absorption coefficient spectra conducted using 3D printed test articles in a normal incidence acoustic impedance tube yield good correlation with simulations. More than 100 Hz of continuous bandwidth with an absorption coefficient greater than 0.6 is shown to be possible in the 300 to 400 Hz range with a 38.1-mm (1.5-inch) thick liner. Further, the influence of face sheet type, Mach number, and sound pressure level on the attenuation across folded core liners is evaluated using grazing flow impedance tube tests. Up to 20 dB of attenuation is observed in the targeted frequency range in these tests indicating potential for performance retention in an operational scenario. With current additive and hybrid manufacturing techniques attaining critical commercial maturity, lightweight and compact acoustic liners employing folded cores could provide a promising practical solution to mitigate low-frequency airborne noise, especially in aerospace applications.

Cavity Adaptation of Water-Based Restoratives Placed as Liners under a Resin Composite

PubMed Central

Gaintantzopoulou, Maria D.; Eliades, George

2017-01-01

Purpose. To investigate the cavity adaptation of mineral trioxide (ProRoot MTA/MT), tricalcium silicate (Biodentine/BD), and glass ionomer (Equia Fil/EF) cements used as liners and the interfacial integrity between those liners and a composite resin placed as the main restorative material. Materials and Methods. Standardized class I cavities (n: 8 per group) were prepared in upper premolars. Cavities were lined with a 1 mm thick layer of each of the tested materials and restored with Optibond FL adhesive and Herculite Precis composite resin. Cavity adaptation of the restorations was investigated by computerized X-ray microtomography. The regions of interest (ROI) were set at the cavity-liner (CL) interface and the liner-resin (LR) interface. The percentage void volume fraction (%VVF) in the ROI was calculated. The specimens were then sectioned and the interfaces were evaluated by reflection optical microscopy, to measure the % length (%LD) of the interfacial gaps. Selected samples were further evaluated by scanning electron microscopy. Statistical analysis was performed by two-way ANOVA and Student-Newman-Keuls multiple comparison test (a = 0.05). Results. MT showed significantly higher %VVF and %LD values in CL interfaces than BD and EF (p < 0.05). No significant differences were found among the materials for the same values at the LR interfaces. Conclusions. When used as a composite liner, ProRoot MTA showed inferior cavity adaptation at dentin/liner interface when compared to Biodentine and Equia Fil. PMID:28465685

Labial and Vaginal Microbiology: Effects of Extended Panty Liner Use

PubMed Central

Enane, N. A.; Baldwin, S.; Berg, R. W.

1997-01-01

Objective: The goals of this study were 1) to better define the labial microflora and 2) to evaluate whether extended non-menstrual use of panty liners would increase genital carriage of undesirable bacteria and predispose to infection. Methods: Healthy female volunteers (224) were prospectively randomized into panty liner wear groups A (Always® deodorant) and B (Always® non-deodorant) and into a control group C (no panty liner wear) with instructions for non-menstrual ± menstrual use ≥5 h daily for 6 months. Selected aerobic bacteria were semiquantitatively cultured from the inner labial groove, the posterior fornix of the vagina, and the cervix pre-study and post-study. Used panty liners were quantitatively cultured, and vaginal secretions were examined by gas chromatography for fatty acid ratios as a measure of microbial flora shifts. Results: At the pre-study, labial microflora in this study population contained significantly higher frequencies of Staphylococcus, coliforms, other gram-negative rods, and enterococci, and a decreased frequency of Gardnerella vaginalis relative to the vaginal microflora. After 6 months use of panty liners the frequencies (and densities) of the selected microorganisms in these two sites had not changed compared to controls, and fatty acid analyses of vaginal secretions gave no evidence of shifts in the microbial flora. Conclusions: Frequencies of selected genital microflora were different for the labia compared to the vagina. No increased carriage of medically important species was detected for either site after 6 months of daily (average 7.8 h) panty liner use. PMID:18476146

PORTSMOUTH ON-SITE DISPOSAL CELL HIGH DENSITY POLYETHYLENE GEOMEMBRANE LONGEVITY

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

Phifer, M.

It is anticipated that high density polyethylene (HDPE) geomembranes will be utilized within the liner and closure cap of the proposed On-Site Disposal Cell (OSDC) at the Portsmouth Gaseous Diffusion Plant. The likely longevity (i.e. service life) of HDPE geomembranes in OSDC service is evaluated within the following sections of this report: (1) Section 2.0 provides an overview of HDPE geomembranes, (2) Section 3.0 outlines potential HDPE geomembranes degradation mechanisms, (3) Section 4.0 evaluates the applicability of HDPE geomembrane degradation mechanisms to the Portsmouth OSDC, (4) Section 5.0 provides a discussion of the current state of knowledge relative to themore » longevity (service life) of HDPE geomembranes, including the relation of this knowledge to the Portsmouth OSDC, and (5) Section 6.0 provides summary and conclusions relative to the anticipated service life of HDPE geomembranes in OSDC service. Based upon this evaluation it is anticipated that the service life of HDPE geomembranes in OSDC service would be significantly greater than the 200 year service life assumed for the OSDC closure cap and liner HDPE geomembranes. That is, a 200 year OSDC HDPE geomembrane service life is considered a conservative assumption.« less

Cu-Cr-Nb-Zr Alloy for Rocket Engines and Other High-Heat- Flux Applications

NASA Technical Reports Server (NTRS)

Ellis, David L.

2013-01-01

Rocket-engine main combustion chamber liners are used to contain the burning of fuel and oxidizer and provide a stream of high-velocity gas for propulsion. The liners in engines such as the Space Shuttle Main Engine are regeneratively cooled by flowing fuel, e.g., cryogenic hydrogen, through cooling channels in the back side of the liner. The heat gained by the liner from the flame and compression of the gas in the throat section is transferred to the fuel by the liner. As a result, the liner must either have a very high thermal conductivity or a very high operating temperature. In addition to the large heat flux (>10 MW/sq m), the liners experience a very large thermal gradient, typically more than 500 C over 1 mm. The gradient produces thermally induced stresses and strains that cause low cycle fatigue (LCF). Typically, a liner will experience a strain differential in excess of 1% between the cooling channel and the hot wall. Each time the engine is fired, the liner undergoes an LCF cycle. The number of cycles can be as few as one for an expendable booster engine, to as many as several thousand for a reusable launch vehicle or reaction control system. Finally, the liners undergo creep and a form of mechanical degradation called thermal ratcheting that results in the bowing out of the cooling channel into the combustion chamber, and eventual failure of the liner. GRCop-84, a Cu-Cr-Nb alloy, is generally recognized as the best liner material available at the time of this reporting. The alloy consists of 14% Cr2Nb precipitates in a pure copper matrix. Through experimental work, it has been established that the Zr will not participate in the formation of Laves phase precipitates with Cr and Nb, but will instead react with Cu to form the desired Cu-Zr compounds. It is believed that significant improvements in the mechanical properties of GRCop-84 will be realized by adding Zr. The innovation is a Cu-Cr-Nb-Zr alloy covering the composition range of 0.8 to 8.1 weight percent Cr, 0.7 to 7.2 weight percent Nb, 0.1 to 1.5 weight percent Zr, and balance Cu. The alloy combines two known strengthening mechanisms - dispersion strengthening by Cr2Nb precipitates (GRCop-84), and precipitation strengthening by CuxZr (AMZIRC) - to produce a synergistic increase in the capabilities of the alloy with the goal of achieving properties greater than either of the methods could achieve alone. The anticipated advantages of the alloy are higher strength at temperatures up to 700 C, improved creep strength, and significantly higher LCF lives relative to GRCop-84. The thermal expansion, thermal conductivity, and processing of the alloy are anticipated to remain largely unchanged relative to GRCop-84.

Thrust stand evaluation of engine performance improvement algorithms in an F-15 airplane

NASA Technical Reports Server (NTRS)

Conners, Timothy R.

1992-01-01

Results are presented from the evaluation of the performance seeking control (PSC) optimization algorithm developed by Smith et al. (1990) for F-15 aircraft, which optimizes the quasi-steady-state performance of an F100 derivative turbofan engine for several modes of operation. The PSC algorithm uses onboard software engine model that calculates thrust, stall margin, and other unmeasured variables for use in the optimization. Comparisons are presented between the load cell measurements, PSC onboard model thrust calculations, and posttest state variable model computations. Actual performance improvements using the PSC algorithm are presented for its various modes. The results of using PSC algorithm are compared with similar test case results using the HIDEC algorithm.

Using 25 Percent / 75 Percent ATJ/JP-8 Blend Rotary Fuel Injection Pump Wear Testing at Elevated Temperature

DTIC Science & Technology

2015-09-01

Transfer Pump Liner before Testing with 25/75 ATJ/JP-8 Fuel with 9-ppm CI/LI...46 Figure 26. Pump SN:16756534 Transfer Pump Liner with 251-hours Testing with 25/75 ATJ/JP-8 Fuel...Transfer Pump Liner before Testing with 25/75 ATJ/JP-8 Fuel with 9-ppm CI/LI

[Comparative study of the antimicrobial effect of various cavity liners used in conservative dentistry].

PubMed

Pumarola Suñé, J; Espias Gómez, A; Canalda Sahli, C

1989-01-01

We have compared the microbiological activity of the following cavity liners: Life, Dycal II, Calcipulpe, Pure calcium hydroxide and Cavitec; against five different bacterial strains: Veillonella parvula, Bacteroides fragilis, Peptococcus s.p., Staphylococcus aureus, and Streptococcus beta hemolytic: The results demonstrate the higher antimicrobial activity of the manufactured cavity liners with calcium hydroxide base in comparison with the pure calcium hydroxide.

The Submarine, 1776-1918

DTIC Science & Technology

2004-01-01

destruction of many civilian lives in sunken passenger ships—notably the Cunard liner Lusitania , attacked in May 1915 with a loss of 1,200 lives, 128...former Ger- man passenger liners interned by their owners in American harbors in order to avoid capture by blockading British cruisers. Eventually there...submarines torpedoed merchant ships, including passenger liners , without warning. Then, because they had no way of rescuing those who had survived the

Effect of beverages on the hardness and tensile bond strength of temporary acrylic soft liners to acrylic resin denture base.

PubMed

Safari, A; Vojdani, M; Mogharrabi, S; Iraji Nasrabadi, N; Derafshi, R

2013-12-01

Two potential problems commonly identified with a denture base incorporating a resilient liner are failure of the bond between acrylic resin and soft liner material, and loss of resiliency of the soft liner over time. Since patients may drink different beverages, it is important to evaluate their effects on physical properties of soft lining materials. The objective of this in vitro study was to evaluate the effect of different beverages on the hardness of two temporary acrylic-based soft lining materials and their bond strength to the denture base resin. For the hardness test; a total of 80 rectangular specimens (40mm×10mm×3mm) were fabricated from a heat-polymerized polymethylmethacrylate. Two commercially auto-polymerized acrylic resin-based resilient liners; Coe-Soft and Visco-gel were prepared according to the manufacturers' instructions and applied on the specimens. For the tensile test, 160 cylindrical specimens (30mm×10mm) were prepared. The liners were added between specimens with a thickness of 3 mm. The specimens of both soft liners were divided into 4 groups (n=10) and immersed in distilled water as the control group, Coca-Cola, 8% and 50% ethanol. All groups were stored in separate containers at 37(o)C for 12 days. All beverages were changed daily. The hardness was determined using a Shore A durometer and tensile bond strength was determined in a ZwickRoell testing machine at a cross-head speed of 5mm/min. The results were analyzed using two-way ANOVA. There was no significant interaction between the soft liners and the drinks for both hardness (p= 0.748) and bond strength (p= 0.902). There were statistically significant differences between all drinks for both hardness (p< 0.001) and bond strength (p< 0.05). Within the limitations of this study, it seems that drinking Coca-Cola and alcoholic beverages would not be potentially causing any problems for the temporary acrylic soft liners.

Optimization of Acoustic Pressure Measurements for Impedance Eduction

NASA Technical Reports Server (NTRS)

Jones, M. G.; Watson, W. R.; Nark, D. M.

2007-01-01

As noise constraints become increasingly stringent, there is continued emphasis on the development of improved acoustic liner concepts to reduce the amount of fan noise radiated to communities surrounding airports. As a result, multiple analytical prediction tools and experimental rigs have been developed by industry and academia to support liner evaluation. NASA Langley has also placed considerable effort in this area over the last three decades. More recently, a finite element code (Q3D) based on a quasi-3D implementation of the convected Helmholtz equation has been combined with measured data acquired in the Langley Grazing Incidence Tube (GIT) to reduce liner impedance in the presence of grazing flow. A new Curved Duct Test Rig (CDTR) has also been developed to allow evaluation of liners in the presence of grazing flow and controlled, higher-order modes, with straight and curved waveguides. Upgraded versions of each of these two test rigs are expected to begin operation by early 2008. The Grazing Flow Impedance Tube (GFIT) will replace the GIT, and additional capabilities will be incorporated into the CDTR. The current investigation uses the Q3D finite element code to evaluate some of the key capabilities of these two test rigs. First, the Q3D code is used to evaluate the microphone distribution designed for the GFIT. Liners ranging in length from 51 to 610 mm are investigated to determine whether acceptable impedance eduction can be achieved with microphones placed on the wall opposite the liner. This analysis indicates the best results are achieved for liner lengths of at least 203 mm. Next, the effects of moving this GFIT microphone array to the wall adjacent to the liner are evaluated, and acceptable results are achieved if the microphones are placed off the centerline. Finally, the code is used to investigate potential microphone placements in the CDTR rigid wall adjacent to the wall containing an acoustic liner, to determine if sufficient fidelity can be achieved with 32 microphones available for this purpose. Initial results indicate 32 microphones can provide acceptable measurements to support impedance eduction with this test rig.

Interface ring for gas turbine fuel nozzle assemblies

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

Fox, Timothy A.; Schilp, Reinhard

A gas turbine combustor assembly including a combustor liner and a plurality of fuel nozzle assemblies arranged in an annular array extending within the combustor liner. The fuel nozzle assemblies each include fuel nozzle body integral with a swirler assembly, and the swirler assemblies each include a bellmouth structure to turn air radially inwardly for passage into the swirler assemblies. A radially outer removed portion of each of the bellmouth structures defines a periphery diameter spaced from an inner surface of the combustor liner, and an interface ring is provided extending between the combustor liner and the removed portions ofmore » the bellmouth structures at the periphery diameter.« less

Drag Measurements of Porous Plate Acoustic Liners

NASA Technical Reports Server (NTRS)

Wolter, John D.

2005-01-01

This paper presents the results of direct drag measurements on a variety of porous plate acoustic liners. The existing literature describes numerous studies of drag on porous walls with injection or suction, but relatively few of drag on porous plates with neither injection nor suction. Furthermore, the porosity of the porous plate in existing studies is much lower than typically used in acoustic liners. In the present work, the acoustic liners consisted of a perforated face sheet covering a bulk acoustic absorber material. Factors that were varied in the experiment were hole diameter, hole pattern, face sheet thickness, bulk material type, and size of the gap (if any) between the face sheet and the absorber material.

Cryogenic glass-filament-wound tank evaluation

NASA Technical Reports Server (NTRS)

Morris, E. E.; Landes, R. E.

1971-01-01

High-pressure glass-filament-wound fluid storage vessels with thin aluminum liners were designed, fabricated, and tested at ambient and cryogenic temperatures which demonstrated the feasibility of producing such vessels as well as high performance and light weight. Significant developments and advancements were made in solving problems associated with the thin metal liners in the tanks, including liner bonding to the overwrap and high strain magnification at the vessel polar bosses. The vessels had very high burst strengths, and failed in cyclic fatigue tests by local liner fracture and leakage without structural failure of the composite tank wall. The weight of the tanks was only 40 to 55% of comparable 2219-T87 aluminum and Inconel 718 tanks.

Transition duct system with arcuate ceramic liner for delivering hot-temperature gases in a combustion turbine engine

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

Wiebe, David J.

A transition duct system (10) for delivering hot-temperature gases from a plurality of combustors in a combustion turbine engine is provided. The system includes an exit piece (16) for each combustor. The exit piece may include an arcuate connecting segment (36). An arcuate ceramic liner (60) may be inwardly disposed onto a metal outer shell (38) along the arcuate connecting segment of the exit piece. Structural arrangements are provided to securely attach the ceramic liner in the presence of substantial flow path pressurization. Cost-effective serviceability of the transition duct systems is realizable since the liner can be readily removed andmore » replaced as needed.« less

Epitaxial CoSi2 on MOS devices

DOEpatents

Lim, Chong Wee; Shin, Chan Soo; Petrov, Ivan Georgiev; Greene, Joseph E.

2005-01-25

An Si.sub.x N.sub.y or SiO.sub.x N.sub.y liner is formed on a MOS device. Cobalt is then deposited and reacts to form an epitaxial CoSi.sub.2 layer underneath the liner. The CoSi.sub.2 layer may be formed through a solid phase epitaxy or reactive deposition epitaxy salicide process. In addition to high quality epitaxial CoSi.sub.2 layers, the liner formed during the invention can protect device portions during etching processes used to form device contacts. The liner can act as an etch stop layer to prevent excessive removal of the shallow trench isolation, and protect against excessive loss of the CoSi.sub.2 layer.

Progress In Magnetized Target Fusion Driven by Plasma Liners

NASA Technical Reports Server (NTRS)

Thio, Francis Y. C.; Kirkpatrick, Ronald C.; Knapp, Charles E.; Cassibry, Jason; Eskridge, Richard; Lee, Michael; Smith, James; Martin, Adam; Wu, S. T.; Schmidt, George;

Friction Stir Welding of GR-Cop 84 for Combustion Chamber Liners

NASA Technical Reports Server (NTRS)

Russell, Carolyn K.; Carter, Robert; Ellis, David L.; Goudy, Richard

2004-01-01

GRCop-84 is a copper-chromium-niobium alloy developed by the Glenn Research Center for liquid rocket engine combustion chamber liners. GRCop-84 exhibits superior properties over conventional copper-base alloys in a liquid hydrogen-oxygen operating environment. The Next Generation Launch Technology program has funded a program to demonstrate scale-up production capabilities of GR-Cop 84 to levels suitable for main combustion chamber production for the prototype rocket engine. This paper describes a novel method of manufacturing the main combustion chamber liner. The process consists of several steps: extrude the GR-Cop 84 powder into billets, roll the billets into plates, bump form the plates into cylinder halves and friction stir weld the halves into a cylinder. The cylinder is then metal spun formed to near net liner dimensions followed by finish machining to the final configuration. This paper describes the friction stir weld process development including tooling and non-destructive inspection techniques, culminating in the successful production of a liner preform completed through spin forming.

Three Year RSA Evaluation of Vitamin E Diffused Highly Cross-linked Polyethylene Liners and Cup Stability.

PubMed

Sillesen, Nanna H; Greene, Meridith E; Nebergall, Audrey K; Nielsen, Poul T; Laursen, Mogens B; Troelsen, Anders; Malchau, Henrik

2015-07-01

Vitamin E diffusion into highly cross-linked polyethylene (E-XLPE) is a method for enhancing oxidative stability of acetabular liners. The purpose of this study was to evaluate in vivo penetration of E-XLPE using radiostereometric analysis (RSA). Eighty-four hips were recruited into a prospective 10-year RSA. This is the first evaluation of the multicenter cohort after 3-years. All patients received E-XLPE liners (E1, Biomet) and porous-titanium coated cups (Regenerex, Biomet). There was no difference (P=0.450) in median femoral head penetration into the E-XLPE liners at 3-years comparing cobalt-chrome heads (-0.028mm; inter-quartile range (IQR) - 0.065 to 0.047) with ceramic heads (-0.043mm, IQR - 0.143to0.042). The 3-year follow-up indicates minimal E-XLPE liner penetration regardless of head material and minimal early cup movement. Copyright © 2015 Elsevier Inc. All rights reserved.

Performance of a Liner-on-Target Injector for Staged Z-Pinch Experiments

NASA Astrophysics Data System (ADS)

Conti, F.; Valenzuela, J. C.; Narkis, J.; Krasheninnikov, I.; Beg, F.; Wessel, F. J.; Ruskov, E.; Rahman, H. U.; McGee, E.

2016-10-01

We present the design and characterization of a compact liner-on-target injector, used in the Staged Z-pinch experiments conducted on the UNR-NTF Zebra Facility. Previous experiments and analysis indicate that high-Z gas liners produce a uniform and efficient implosion on a low-Z target plasma. The liner gas shell is produced by an annular solenoid valve and a converging-diverging nozzle designed to achieve a collimated, supersonic, Mach-5 flow. The on-axis target is produced by a coaxial plasma gun, where a high voltage pulse is applied to ionize neutral gas and accelerate the plasma by the J-> × B-> force. Measurements of the liner and target dynamics, resolved by interferometry in space and time, fast imaging, and collection of the emitted light, are presented. The results are compared to the predictions from Computational Fluid Dynamics and MHD simulations that model the injector. Optimization of the design parameters, for upcoming Staged Z-pinch experiments, will be discussed. Advanced Research Projects Agency - Energy, DE-AR0000569.

The Performance of Four Different Mineral Liners on the Transportation of Chlorinated Phenolic Compounds to Groundwater in Landfills

PubMed Central

Adar, Elanur; Bilgili, Mehmet Sinan

2015-01-01

The aim of this study was to investigate the efficiency of four different mineral liners (clay, bentonite, kaoline, and zeolite) which could be utilized to prevent the transport of phenolic compounds to groundwater through alternative liner systems. Four laboratory-scale HDPE reactors with 80 cm height and 40 cm inner diameter were operated for a period of 180 days. Results indicated that the transport of mono- or dichlorophenols is significantly prevented by the liner systems used, while the transport of highly chlorinated phenolic compounds cannot be prevented by the landfill liner system effectively. Highly chlorinated phenolic compounds in groundwater can be found in higher concentrations than the leachate, as a result of the degradation and transformation of these compounds. Thus, the analysis of highly chlorinated phenolic compounds such as 2,4,6-TCP, 2,3,6-TCP, 3,4,5-TCP, and PCP is of great significance for the studies to be conducted on the contamination of groundwater around landfills. PMID:26759828

Uncertainty Analysis of the Grazing Flow Impedance Tube

NASA Technical Reports Server (NTRS)

Brown, Martha C.; Jones, Michael G.; Watson, Willie R.

2012-01-01

This paper outlines a methodology to identify the measurement uncertainty of NASA Langley s Grazing Flow Impedance Tube (GFIT) over its operating range, and to identify the parameters that most significantly contribute to the acoustic impedance prediction. Two acoustic liners are used for this study. The first is a single-layer, perforate-over-honeycomb liner that is nonlinear with respect to sound pressure level. The second consists of a wire-mesh facesheet and a honeycomb core, and is linear with respect to sound pressure level. These liners allow for evaluation of the effects of measurement uncertainty on impedances educed with linear and nonlinear liners. In general, the measurement uncertainty is observed to be larger for the nonlinear liners, with the largest uncertainty occurring near anti-resonance. A sensitivity analysis of the aerodynamic parameters (Mach number, static temperature, and static pressure) used in the impedance eduction process is also conducted using a Monte-Carlo approach. This sensitivity analysis demonstrates that the impedance eduction process is virtually insensitive to each of these parameters.

Diagnostics for the plasma liner experiment.

PubMed

Lynn, A G; Merritt, E; Gilmore, M; Hsu, S C; Witherspoon, F D; Cassibry, J T

2010-10-01

The goal of the Plasma Liner Experiment (PLX) is to explore and demonstrate the feasibility of forming imploding spherical "plasma liners" via merging high Mach number plasma jets to reach peak liner pressures of ∼0.1 Mbar using ∼1.5 MJ of initial stored energy. Such a system would provide HED plasmas for a variety of fundamental HEDLP, laboratory astrophysics, and materials science studies, as well as a platform for experimental validation of rad-hydro and rad-MHD simulations. It could also prove attractive as a potential standoff driver for magnetoinertial fusion. Predicted parameters from jet formation to liner stagnation cover a large range of plasma density and temperature, varying from n(i)∼10(16) cm(-3), T(e)≈T(i)∼1 eV at the plasma gun mouth to n(i)>10(19) cm(-3), T(e)≈T(i)∼0.5 keV at stagnation. This presents a challenging problem for the plasma diagnostics suite which will be discussed.

Simulation Study of Structure and Properties of Plasma Liners for the PLX- α Project

NASA Astrophysics Data System (ADS)

Samulyak, Roman; Shih, Wen; Hsu, Scott; PLX-Alpha Team

2017-10-01

Detailed numerical studies of the propagation and merger of high-Mach-number plasma jets and the formation and implosion of plasma liners have been performed using the FronTier code in support of the Plasma Liner Experiment-ALPHA (PLX- α) project. Physics models include radiation, physical diffusion, plasma-EOS models, and an anisotropic diffusion model that mimics deviations from fully collisional hydrodynamics in outer layers of plasma jets. Detailed structure and non-uniformity of plasma liners of due to primary and secondary shock waves have been studies as well as averaged quantities of ram pressure and Mach number. Synthetic data from simulations have been compared with available experimental data from a multi-chord interferometer and survey and high-resolution spectrometers. Numerical studies of the sensitivity of liner properties to experimental errors in the initial masses of jets and the synchronization of plasma gun valves have also been performed. Supported by the ARPA-E ALPHA program.

Numerical and Physical Modeling of the Response of Resonator Liners to Intense Sound and Grazing Flow

NASA Technical Reports Server (NTRS)

Hersh, Alan S.; Tam, Christopher

2009-01-01

Two significant advances have been made in the application of computational aeroacoustics methodology to acoustic liner technology. The first is that temperature effects for discrete sound are not the same as for broadband noise. For discrete sound, the normalized resistance appears to be insensitive to temperature except at high SPL. However, reactance is lower, significantly lower in absolute value, at high temperature. The second is the numerical investigation the acoustic performance of a liner by direct numerical simulation. Liner impedance is affected by the non-uniformity of the incident sound waves. This identifies the importance of pressure gradient. Preliminary design one and two-dimensional impedance models were developed to design sound absorbing liners in the presence of intense sound and grazing flow. The two-dimensional model offers the potential to empirically determine incident sound pressure face-plate distance from resonator orifices. This represents an important initial step in improving our understanding of how to effectively use the Dean Two-Microphone impedance measurement method.

Formation of metal and dielectric liners using a solution process for deep trench capacitors.

PubMed

Ham, Yong-Hyun; Kim, Dong-Pyo; Baek, Kyu-Ha; Park, Kun-Sik; Kim, Moonkeun; Kwon, Kwang-Ho; Shin, Hong-Sik; Lee, Kijun; Do, Lee-Mi

2012-07-01

We demonstrated the feasibility of metal and dielectric liners using a solution process for deep trench capacitor application. The deep Si trench via with size of 10.3 microm and depth of 71 microm were fabricated by Bosch process in deep reactive ion etch (DRIE) system. The aspect ratio was about 7. Then, nano-Ag ink and poly(4-vinylphenol) (PVPh) were used to form metal and dielectric liners, respectively. The thicknesses of the Ag and PVPh liners were about 144 and 830 nm, respectively. When the curing temperature of Ag film increased from 120 to 150 degrees C, the sheet resistance decreased rapidly from 2.47 to 0.72 Omega/sq and then slightly decreased to 0.6 Omega/sq with further increasing the curing temperature beyond 150 degrees C. The proposed liner formation method using solution process is a simple and cost effective process for the high capacity of deep trench capacitor.

Ram-pressure scaling and non-uniformity characterization of a spherically imploding liner formed by hypervelocity plasma jets

NASA Astrophysics Data System (ADS)

Cassibry, Jason; Dougherty, Jesse; Thompson, Seth; Hsu, Scott; Witherspoon, F. D.; University of AL in Huntsville Team; Los Alamos National Laboratory Team; HyperV Technologies Corp. Team

2014-10-01

Three-dimensional modeling of plasma liner formation and implosion is performed using the Smoothed Particle Hydrodynamics Code (SPHC) with radiation, thermal transport, and tabular equations of state (EOS), accounting for ionization, in support of a proposed 60-gun plasma liner formation experiment for plasma-jet driven magneto-inertial fusion (PJMIF). Previous SPHC modeling showed that ideal gas law scaling of peak stagnation pressure increased linearly with density and number of jets, quadratically with jet radius and velocity, and inversely with the initial jet length, while results with tabular EOS, thermal transport, and radiation have greater sensitivity to the initial jet distribution. A series of simulations are conducted to study the effects of initial jet conditions on peak ram pressure and liner non-uniformity during plasma liner implosion. The growth rate of large-amplitude density perturbations introduced by the discrete jets are computed and compared with predictions by the Bell-Plesset equation.

Conductivity and transit time estimates of a soil liner

USGS Publications Warehouse

Krapac, I.G.; Cartwright, K.; Panno, S.V.; Hensel, B.R.; Rehfeldt, K.H.; Herzog, B.L.

1990-01-01

A field-scale soil linear was built to assess the feasibilty of constructing a liner to meet the saturated hydraulic conductivity requirement of the U.S. EPA (i.e., less than 1 ?? 10-7 cm/s), and to determine the breakthrough and transit times of water and tracers through the liner. The liner, 8 ?? 15 ?? 0.9 m, was constructed in 15-cm compacted lifts using a 20,037-kg pad-foot compactor and standard engineering practices. Estimated saturated hydraulic conductivities were 2.4 ?? 10-9 cm/s, based on data from large-ring infiltrometers; 4.0 ?? 10-8 cm/s from small-ring infiltrometers; and 5.0 ?? 10-8 cm/s from a water-balance analysis. These estimates were derived from 1 year of monitoring water infiltration into the linear. Breakthrough of tracers at the base of the liner was estimated to be between 2 and 13 years, depending on the method of calculation and the assumptions used in the calculation.

Applied algorithm in the liner inspection of solid rocket motors

NASA Astrophysics Data System (ADS)

Hoffmann, Luiz Felipe Simões; Bizarria, Francisco Carlos Parquet; Bizarria, José Walter Parquet

2018-03-01

In rocket motors, the bonding between the solid propellant and thermal insulation is accomplished by a thin adhesive layer, known as liner. The liner application method involves a complex sequence of tasks, which includes in its final stage, the surface integrity inspection. Nowadays in Brazil, an expert carries out a thorough visual inspection to detect defects on the liner surface that may compromise the propellant interface bonding. Therefore, this paper proposes an algorithm that uses the photometric stereo technique and the K-nearest neighbor (KNN) classifier to assist the expert in the surface inspection. Photometric stereo allows the surface information recovery of the test images, while the KNN method enables image pixels classification into two classes: non-defect and defect. Tests performed on a computer vision based prototype validate the algorithm. The positive results suggest that the algorithm is feasible and when implemented in a real scenario, will be able to help the expert in detecting defective areas on the liner surface.

Landing Gear Door Liners for Airframe Noise Reduction

NASA Technical Reports Server (NTRS)

Jones, Michael G. (Inventor); Howerton, Brian M. (Inventor); Van De Ven, Thomas (Inventor)

2014-01-01

A landing gear door for retractable landing gear of aircraft includes an acoustic liner. The acoustic liner includes one or more internal cavities or chambers having one or more openings that inhibit the generation of sound at the surface and/or absorb sound generated during operation of the aircraft. The landing gear door may include a plurality of internal chambers having different geometries to thereby absorb broadband noise.

Strain Measurement during Stress Rupture of Composite Over-Wrapped Pressure Vessel with Fiber Bragg Gratings Sensors

NASA Technical Reports Server (NTRS)

Banks, Curtis E.; Grant, Joseph; Russell, Sam; Arnett, Shawn

2008-01-01

Fiber optic Bragg gratings were used to measure strain fields during Stress Rupture (SSM) test of Kevlar Composite Over-Wrapped Pressure Vessels (COPV). The sensors were embedded under the over-wrapped attached to the liner released from the Kevlar and attached to the Kevlar released from the liner. Additional sensors (foil gages and fiber bragg gratings) were surface mounted on the COPY liner.

Helium High Pressure Tanks at EADS Space Transportation New Technology with Thermoplastic Liner

DTIC Science & Technology

2005-07-13

l’art actuel pour l’application d’un liner thermoplastique sur le réservoir hélium 300 litres pour le lanceur ARIANE 5, réservoir actuellement réalisé à...L à liner thermoplastique ont complètement démontré le respect aux exigences majeures demandées pour le lanceur A5. Ces travaux finalisent la phase

In situ reactor

DOEpatents

Radtke, Corey William; Blackwelder, David Bradley

2004-01-27

An in situ reactor for use in a geological strata, is described and which includes a liner defining a centrally disposed passageway and which is placed in a borehole formed in the geological strata; and a sampling conduit is received within the passageway defined by the liner and which receives a geological specimen which is derived from the geological strata, and wherein the sampling conduit is in fluid communication with the passageway defined by the liner.

Military Geography for Professionals and the Public

DTIC Science & Technology

1998-03-01

Cunard ocean liner Lusitania with I, 1 98 men, women, and children aboard. Submarines and antisubmarine warfare (ASW) forces have played...34 luxury liner took a one-way trip to Davy Jones’ locker. Glacial tongues of 52 PART ONE: PIIYSICAL GEOGRAPHY Figure 9. Ocean Wave Motions and Measurements...winds dictate the orientation of these fields. No ocean liner or cruise ship ever deliberately heads toward a storm, as carrier commanding officers

Failure Surfaces for the Design of Ceramic-Lined Gun Tubes

DTIC Science & Technology

2004-12-01

density than steel making them attractive candidates as gun tube liners . A new design approach is necessary to address the large variability in strength...systems. Having established the failure criterion for the ceramic liner as the Weibull probability of failure, the need for a suitable failure...Report AMMRC SP-82-1, Materials Technology Laboratory, Watertown, Massachusetts, 1982. 7 R. Katz, Ceramic Gun Barrel Liners : Retrospect and Prospect

Optimisation of micro-perforated cylindrical silencers in linear and nonlinear regimes

NASA Astrophysics Data System (ADS)

Bravo, Teresa; Maury, Cédric; Pinhède, Cédric

2016-02-01

This paper describes analytical and experimental studies conducted to understand the potential of lightweight non-fibrous alternatives to dissipative mufflers for in-duct noise control problems, especially under high sound pressure levels (SPLs) and in the low frequency domain. The cost-efficient multi-modal propagation method has been extended to predict nonlinear effects in the dissipation and the transmission loss (TL) of micro-perforated cylindrical liners with sub-millimetric holes diameter. A validation experiment was performed in a standing wave tube to measure the power dissipated and transmitted by a nonlocally reacting liner under moderate and high SPLs. Although nonlinear effects significantly reduce the dissipation and TL around the liner maximum damping frequency, these power quantities may be enhanced below the half-bandwidth resonance. An optimal value of the in-hole peak particle velocity has been found that maximizes the TL of locally reacting liners at low frequencies. Optimisation studies based on dissipation or TL maximization showed the sensitivity of the liner constituting parameters to variations in the design target range such as the center frequency, the levels of acoustic excitation and the nature of the surface impedance (locally or nonlocally reacting). An analysis is proposed of the deviation observed at low frequencies between the optimum impedance of the locally reacting liner under moderate SPLs and Cremer's optimum impedances.

Large Engine Technology Program. Task 21: Rich Burn Liner for Near Term Experimental Evaluations

NASA Technical Reports Server (NTRS)

Hautman, D. J.; Padget, F. C.; Kwoka, D.; Siskind, K. S.; Lohmann, R. P.

2005-01-01

The objective of the task reported herein, which was conducted as part of the NASA sponsored Large Engine Technology program, was to define and evaluate a near-term rich-zone liner construction based on currently available materials and fabrication processes for a Rich-Quench-Lean combustor. This liner must be capable of operation at the temperatures and pressures of simulated HSCT flight conditions but only needs sufficient durability for limited duration testing in combustor rigs and demonstrator engines in the near future. This must be achieved at realistic cooling airflow rates since the approach must not compromise the emissions, performance, and operability of the test combustors, relative to the product engine goals. The effort was initiated with an analytical screening of three different liner construction concepts. These included a full cylinder metallic liner and one with multiple segments of monolithic ceramic, both of which incorporated convective cooling on the external surface using combustor airflow that bypassed the rich zone. The third approach was a metallic platelet construction with internal convective cooling. These three metal liner/jacket combinations were tested in a modified version of an existing Rich-Quench-Lean combustor rig to obtain data for heat transfer model refinement and durability verification.

Purpose-built PDC bit successfully drills 7-in liner equipment and formation: An integrated solution

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

Puennel, J.G.A.; Huppertz, A.; Huizing, J.

1996-12-31

Historically, drilling out the 7-in, liner equipment has been a time consuming operation with a limited success ratio. The success of the operation is highly dependent on the type of drill bit employed. Tungsten carbide mills and mill tooth rock bits required from 7.5 to 11.5 hours respectively to drill the pack-off bushings, landing collar, shoe track and shoe. Rates of penetration dropped dramatically when drilling the float equipment. While conventional PDC bits have drilled the liner equipment successfully (averaging 9.7 hours), severe bit damage invariably prevented them from continuing to drill the formation at cost-effective penetration rates. This papermore » describes the integrated development and application of an IADC M433 Class PDC bit, which was designed specifically to drill out the 7-in. liner equipment and continue drilling the formation at satisfactory penetration rates. The development was the result of a joint investigation There the operator and bit/liner manufacturers shared their expertise in solving a drilling problem, The heavy-set bit was developed following drill-off tests conducted to investigate the drillability of the 7-in. liner equipment. Key features of the new bit and its application onshore The Netherlands will be presented and analyzed.« less

Boundary layer effects on liners for aircraft engines

NASA Astrophysics Data System (ADS)

Gabard, Gwénaël

2016-10-01

The performance of acoustic treatments installed on aircraft engines is strongly influenced by the boundary layer of the grazing flow on the surface of the liner. The parametric study presented in this paper illustrates the extent of this effect and identifies when it is significant. The acoustic modes of a circular duct with flow are calculated using a finite difference method. The parameters are representative of the flow conditions, liners and sound fields found in current turbofan engines. Both the intake and bypass ducts are considered. Results show that there is a complex interplay between the boundary layer thickness, the direction of propagation and the liner impedance and that the boundary layer can have a strong impact on liner performance for typical configurations (including changes of the order of 30 dB on the attenuation of modes associated with tonal fan noise). A modified impedance condition including the effect of a small but finite boundary layer thickness is considered and compared to the standard Myers condition based on an infinitely thin boundary layer. We show how this impedance condition can be implemented in a mode calculation method by introducing auxiliary variables. This condition is able to capture the trends associated with the boundary layer effects and in most cases provides improved predictions of liner performance.

Shock formation in Ne, Ar, Kr, and Xe on deuterium gas puff implosions

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

Narkis, J.; Rahman, H. U.; Ney, P.

2016-12-29

1- and 2-D simulations of 1-cm radius, gas-puff liners of Ne, Ar, Kr, and Xe imploding onto a deuterium target are conducted using the discharge parameters for the Zebra (1 MA, 130 ns) driver using the resistive MHD code MACH2. This is an implementation of the Staged Z-pinch concept, in which the target is driven to high-energy-density first by shock compression launched by a diffused azimuthal magnetic field (J×B force), and then by the adiabatic compression as the liner converges on axis. During the run-in phase, the initial shock heating preheats the deuterium plasma, with a subsequent stable, adiabatic compressionmore » heating the target to high energy density. Shock compression of the target coincides with the development of a J×B force at the target/liner interface. Stronger B-field transport and earlier shock compression increases with higher-Z liners, which results in an earlier shock arrival on axis. As a result, delayed shock formation in lower-Z liners yields a relative increase in shock heating, however, the 2-D simulations show an increased target isolation from magneto-Rayleigh-Taylor instability penetration, suggesting that an optimal balance between these two effects is reached in an Ar or Kr liner, rather than with Xe.« less

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

Awe, T. J., E-mail: tjawe@sandia.gov; Jennings, C. A.; McBride, R. D.

Recent experiments at the Sandia National Laboratories Z Facility have, for the first time, studied the implosion dynamics of magnetized liner inertial fusion (MagLIF) style liners that were pre-imposed with a uniform axial magnetic field. As reported [T. J. Awe et al., Phys. Rev. Lett. 111, 235005 (2013)] when premagnetized with a 7 or 10 T axial field, these liners developed 3D-helix-like hydrodynamic instabilities; such instabilities starkly contrast with the azimuthally correlated magneto-Rayleigh-Taylor (MRT) instabilities that have been consistently observed in many earlier non-premagnetized experiments. The helical structure persisted throughout the implosion, even though the azimuthal drive field greatly exceeded themore » expected axial field at the liner's outer wall for all but the earliest stages of the experiment. Whether this modified instability structure has practical importance for magneto-inertial fusion concepts depends primarily on whether the modified instability structure is more stable than standard azimuthally correlated MRT instabilities. In this manuscript, we discuss the evolution of the helix-like instability observed on premagnetized liners. While a first principles explanation of this observation remains elusive, recent 3D simulations suggest that if a small amplitude helical perturbation can be seeded on the liner's outer surface, no further influence from the axial field is required for the instability to grow.« less

Modelling the impact of liner shipping network perturbations on container cargo routing: Southeast Asia to Europe application.

PubMed

Achurra-Gonzalez, Pablo E; Novati, Matteo; Foulser-Piggott, Roxane; Graham, Daniel J; Bowman, Gary; Bell, Michael G H; Angeloudis, Panagiotis

2016-06-03

Understanding how container routing stands to be impacted by different scenarios of liner shipping network perturbations such as natural disasters or new major infrastructure developments is of key importance for decision-making in the liner shipping industry. The variety of actors and processes within modern supply chains and the complexity of their relationships have previously led to the development of simulation-based models, whose application has been largely compromised by their dependency on extensive and often confidential sets of data. This study proposes the application of optimisation techniques less dependent on complex data sets in order to develop a quantitative framework to assess the impacts of disruptive events on liner shipping networks. We provide a categorization of liner network perturbations, differentiating between systemic and external and formulate a container assignment model that minimises routing costs extending previous implementations to allow feasible solutions when routing capacity is reduced below transport demand. We develop a base case network for the Southeast Asia to Europe liner shipping trade and review of accidents related to port disruptions for two scenarios of seismic and political conflict hazards. Numerical results identify alternative routing paths and costs in the aftermath of port disruptions scenarios and suggest higher vulnerability of intra-regional connectivity. Copyright © 2016 Elsevier Ltd. All rights reserved.

Strength, Fatigue, and Fracture Toughness of Ti-6Al-4V Liner from a Composite Over-Wrapped Pressure Vessel

NASA Technical Reports Server (NTRS)

Salem, Jonathan A.; Lerch, Brad; Thesken, John C.; Sutter, Jim; Russell, Richard

2008-01-01

It was demonstrated by way of experiment that Composite Over-wrapped Pressure Vessel (COPV) Ti-6Al-4V liner material can sustain the expected service loads and cycles. The experiments were performed as part of investigations on the residual life of COPV tanks being used in Space Shuttle Orbiters. Measured properties included tensile strength, compressive strength, reversed loading cycles to simulate liner proof strains, and cyclic fatigue loading to demonstrate the ability to sustain 1000 cycles after liner buckling. The liner material came from a salvaged 40 in. Columbia (orbiter 102) tank (SN029), and tensile strength measurements were made on both boss-transition (thick) and membrane regions (thin). The average measured yield strength was 131 ksi in the boss-transition and membrane regions, in good agreement with measurements made on 1970 s vintage forged plate stock. However, Young s modulus was 17.4+/-0.3 Msi, somewhat higher than typical handbook values (approx.16 Msi). The fracture toughness, as estimated from a failed fatigue specimen, was 74 ksi/sq in, in reasonable agreement with standardized measurements made on 1970 s vintage forged plate stock. Low cycle fatigue of a buckled test specimen implied that as-imprinted liners can sustain over 4000 load cycles.

Analytical and experimental studies of an optimum multisegment phased liner noise suppression concept

NASA Technical Reports Server (NTRS)

Sawdy, D. T.; Beckemeyer, R. J.; Patterson, J. D.

1976-01-01

Results are presented from detailed analytical studies made to define methods for obtaining improved multisegment lining performance by taking advantage of relative placement of each lining segment. Properly phased liner segments reflect and spatially redistribute the incident acoustic energy and thus provide additional attenuation. A mathematical model was developed for rectangular ducts with uniform mean flow. Segmented acoustic fields were represented by duct eigenfunction expansions, and mode-matching was used to ensure continuity of the total field. Parametric studies were performed to identify attenuation mechanisms and define preliminary liner configurations. An optimization procedure was used to determine optimum liner impedance values for a given total lining length, Mach number, and incident modal distribution. Optimal segmented liners are presented and it is shown that, provided the sound source is well-defined and flow environment is known, conventional infinite duct optimum attenuation rates can be improved. To confirm these results, an experimental program was conducted in a laboratory test facility. The measured data are presented in the form of analytical-experimental correlations. Excellent agreement between theory and experiment verifies and substantiates the analytical prediction techniques. The results indicate that phased liners may be of immediate benefit in the development of improved aircraft exhaust duct noise suppressors.

Advanced Turbofan Duct Liner Concepts

NASA Technical Reports Server (NTRS)

Bielak, Gerald W.; Premo, John W.; Hersh, Alan S.

1999-01-01

The Advanced Subsonic Technology Noise Reduction Program goal is to reduce aircraft noise by 10 EPNdB by the year 2000 relative, to 1992 technology. The improvement goal for nacelle attenuation is 25% relative to 1992 technology by 1997 and 50% by 2000. The Advanced Turbofan Duct Liner Concepts Task work by Boeing presented in this document was in support of these goals. The basis for the technical approach was a Boeing study conducted in 1993-94 under NASA/FAA contract NAS1-19349, Task 6, investigating broadband acoustic liner concepts. As a result of this work, it was recommended that linear double layer, linear and perforate triple layer, parallel element, and bulk absorber liners be further investigated to improve nacelle attenuations. NASA LaRC also suggested that "adaptive" liner concepts that would allow "in-situ" acoustic impedance control also be considered. As a result, bias flow and high-temperature liner concepts were also added to the investigation. The major conclusion from the above studies is that improvements in nacelle liner average acoustic impedance characteristics alone will not result in 25% increased nacelle noise reduction relative to 1992 technology. Nacelle design advancements currently being developed by Boeing are expected to add 20-40% more acoustic lining to hardwall regions in current inlets, which is predicted to result in and additional 40-80% attenuation improvement. Similar advancements are expected to allow 10-30% more acoustic lining in current fan ducts with 10-30% more attenuation expected. In addition, Boeing is currently developing a scarf inlet concept which is expected to give an additional 40-80% attenuation improvement for equivalent lining areas.

Axial magnetic field injection in magnetized liner inertial fusion

NASA Astrophysics Data System (ADS)

Gourdain, P.-A.; Adams, M. B.; Davies, J. R.; Seyler, C. E.

2017-10-01

MagLIF is a fusion concept using a Z-pinch implosion to reach thermonuclear fusion. In current experiments, the implosion is driven by the Z-machine using 19 MA of electrical current with a rise time of 100 ns. MagLIF requires an initial axial magnetic field of 30 T to reduce heat losses to the liner wall during compression and to confine alpha particles during fusion burn. This field is generated well before the current ramp starts and needs to penetrate the transmission lines of the pulsed-power generator, as well as the liner itself. Consequently, the axial field rise time must exceed hundreds of microseconds. Any coil capable of being submitted to such a field for that length of time is inevitably bulky. The space required to fit the coil near the liner, increases the inductance of the load. In turn, the total current delivered to the load decreases since the voltage is limited by driver design. Yet, the large amount of current provided by the Z-machine can be used to produce the required 30 T field by tilting the return current posts surrounding the liner, eliminating the need for a separate coil. However, the problem now is the field penetration time, across the liner wall. This paper discusses why skin effect arguments do not hold in the presence of resistivity gradients. Numerical simulations show that fields larger than 30 T can diffuse across the liner wall in less than 60 ns, demonstrating that external coils can be replaced by return current posts with optimal helicity.

SDU6 Interior Liner Testing & Evaluation

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

Skidmore, T. E.

Two liner materials (Marseal® M-3500 and REMA Chemoline® 4CN) proposed for use as a liner inside the Saltstone Disposal Unit 6 (SDU6) were subjected to specific ASTM tests (tensile and lap-shear) after immersion in 50% and 100% simulant solutions for 1000 hours at the Savannah River Ecology Laboratory. Both liner materials exhibited good resistance to the simulant chemistry, at least based on the tests performed and the test duration/conditions imposed. In lap-shear tests, both materials failed in the base material rather than peeling apart, confirming good adhesion. The REMA 4CN bromobutyl elastomer showed superior bonding characteristics and absence of warpingmore » or delamination at the conditions tested. The Marseal M-3500 material (PVC/EVA blend with polyester reinforcement) exhibited deformation and debonding in some locations. The cause of the deformation and delamination observed in the Marseal M-3500 material is not fully known, but possibly attributed to thermomechanical stress at immersion temperatures, and the thermoplastic nature of the material. The immersion temperature (68 °C) is slightly greater than the maximum use temperature limit quoted for the Marseal M- 3500 liner (65 °C), though the basis for the service limit is unknown. The testing performed was limited in scope and only for these two liner materials. These tests were primarily performed to screen for severe incompatibility or short-term degradation in Saltstone bleedwater simulants at bounding solution temperatures. Additional testing is recommended to assess long-term performance and the overall service life of the liner.« less

Tests for the evaluation of ammonium attenuation in MSW landfill leachate by adsorption into bentonite in a landfill liner.

PubMed

Pivato, A; Raga, R

2006-01-01

Uncontrolled leachate emissions are one of the key factors in the environmental impact of municipal solid waste (MSW) landfills. The concentration of ammonium, given the anaerobic conditions in traditional landfills, can remain significantly high for a very long period of time, as degradation does not take place and volatilisation is not significant (the pH is not high enough to considerably shift the equilibrium towards un-ionised ammonia). Recent years have witnessed a continuous enhancement of landfill technology in order to minimize uncontrolled emissions into the environment; bottom lining systems have been improved and more attention has been devoted to the study of the attenuation of the different chemicals in leachate in case of migration through the mineral barrier. Different natural materials have been considered for use as components of landfill liners in the last years and tested in order to evaluate the performance of the different alternatives. Among those materials, bentonite is often used, coupled with other materials in two different ways: in addition to in situ soil or in geocomposite clay liner (GCL). A lab-scale test was carried out in order to further investigate the influence of bentonite on the attenuation of ammonium in leachate passing through a landfill liner. Two different tests were conducted: a standardized batch test with pulverized bentonite and a batch test with compacted bentonite. The latter was proposed in order to better simulate the real conditions in a landfill liner. The two tests produced values for the partition coefficient K(d) higher than the average measured for other natural materials usually utilized as components of landfill liners. Moreover, the two tests showed similar results, thus providing a further validation of the suitability of the standard batch test with pulverized bentonite. A thorough knowledge of attenuation processes of ammonium in landfill liners is the basis for the application of risk analysis models for the evaluation of the failure of bottom liners or their components.

Mass ablation and magnetic flux losses through a magnetized plasma-liner wall interface

NASA Astrophysics Data System (ADS)

García-Rubio, F.; Sanz, J.

2017-07-01

The understanding of energy and magnetic flux losses in a magnetized plasma medium confined by a cold wall is of great interest in the success of magnetized liner inertial fusion (MagLIF). In a MagLIF scheme, the fuel is magnetized and subsonically compressed by a cylindrical liner. Magnetic flux conservation is degraded by the presence of gradient-driven transport processes such as thermoelectric effects (Nernst) and magnetic field diffusion. In previous publications [Velikovich et al., Phys. Plasmas 22, 042702 (2015)], the evolution of a hot magnetized plasma in contact with a cold solid wall (liner) was studied using the classical collisional Braginskii's plasma transport equations in one dimension. The Nernst term degraded the magnetic flux conservation, while both thermal energy and magnetic flux losses were reduced with the electron Hall parameter ωeτe with a power-law asymptotic scaling (ωeτe)-1/2. In the analysis made in the present paper, we consider a similar situation, but with the liner being treated differently. Instead of a cold solid wall acting as a heat sink, we model the liner as a cold dense plasma with low thermal conduction (that could represent the cryogenic fuel layer added on the inner surface of the liner in a high-gain MagLIF configuration). Mass ablation comes into play, which adds notably differences to the previous analysis. The direction of the plasma motion is inverted, but the Nernst term still convects the magnetic field towards the liner. Magnetization suppresses the Nernst velocity and improves the magnetic flux conservation. Thermal energy in the hot plasma is lost in heating the ablated material. When the electron Hall parameter is large, mass ablation scales as (ωeτe)-3/10, while both the energy and magnetic flux losses are reduced with a power-law asymptotic scaling (ωeτe)-7/10.

Simulation studies of hydrodynamic aspects of magneto-inertial fusion and high order adaptive algorithms for Maxwell equations

NASA Astrophysics Data System (ADS)

Wu, Lingling

Three-dimensional simulations of the formation and implosion of plasma liners for the Plasma Jet Induced Magneto Inertial Fusion (PJMIF) have been performed using multiscale simulation technique based on the FronTier code. In the PJMIF concept, a plasma liner, formed by merging of a large number of radial, highly supersonic plasma jets, implodes on the target in the form of two compact plasma toroids, and compresses it to conditions of the nuclear fusion ignition. The propagation of a single jet with Mach number 60 from the plasma gun to the merging point was studied using the FronTier code. The simulation result was used as input to the 3D jet merger problem. The merger of 144, 125, and 625 jets and the formation and heating of plasma liner by compression waves have been studied and compared with recent theoretical predictions. The main result of the study is the prediction of the average Mach number reduction and the description of the liner structure and properties. We have also compared the effect of different merging radii. Spherically symmetric simulations of the implosion of plasma liners and compression of plasma targets have also been performed using the method of front tracking. The cases of single deuterium and xenon liners and double layer deuterium - xenon liners compressing various deuterium-tritium targets have been investigated, optimized for maximum fusion energy gains, and compared with theoretical predictions and scaling laws of [P. Parks, On the efficacy of imploding plasma liners for magnetized fusion target compression, Phys. Plasmas 15, 062506 (2008)]. In agreement with the theory, the fusion gain was significantly below unity for deuterium - tritium targets compressed by Mach 60 deuterium liners. In the most optimal setup for a given chamber size that contained a target with the initial radius of 20 cm compressed by 10 cm thick, Mach 60 xenon liner, the target ignition and fusion energy gain of 10 was achieved. Simulations also showed that composite deuterium - xenon liners reduce the energy gain due to lower target compression rates. The effect of heating of targets by alpha particles on the fusion energy gain has also been investigated. The study of the dependence of the ram pressure amplification on radial compressibility showed a good agreement with the theory. The study concludes that a liner with higher Mach number and lower adiabatic index gamma (the radio of specific heats) will generate higher ram pressure amplification and higher fusion energy gain. We implemented a second order embedded boundary method for the Maxwell equations in geometrically complex domains. The numerical scheme is second order in both space and time. Comparing to the first order stair-step approximation of complex geometries within the FDTD method, this method can avoid spurious solution introduced by the stair step approximation. Unlike the finite element method and the FE-FD hybrid method, no triangulation is needed for this scheme. This method preserves the simplicity of the embedded boundary method and it is easy to implement. We will also propose a conservative (symplectic) fourth order scheme for uniform geometry boundary.

Cooling Duct Analysis for Transpiration/Film Cooled Liquid Propellant Rocket Engines

NASA Technical Reports Server (NTRS)

Micklow, Gerald J.

1996-01-01

The development of a low cost space transportation system requires that the propulsion system be reusable, have long life, with good performance and use low cost propellants. Improved performance can be achieved by operating the engine at higher pressure and temperature levels than previous designs. Increasing the chamber pressure and temperature, however, will increase wall heating rates. This necessitates the need for active cooling methods such as film cooling or transpiration cooling. But active cooling can reduce the net thrust of the engine and add considerably to the design complexity. Recently, a metal drawing process has been patented where it is possible to fabricate plates with very small holes with high uniformity with a closely specified porosity. Such a metal plate could be used for an inexpensive transpiration/film cooled liner to meet the demands of advanced reusable rocket engines, if coolant mass flow rates could be controlled to satisfy wall cooling requirements and performance. The present study investigates the possibility of controlling the coolant mass flow rate through the porous material by simple non-active fluid dynamic means. The coolant will be supplied to the porous material by series of constant geometry slots machined on the exterior of the engine.

Pratt & Whitney 2D Model in LeRC 9 ft x 15 ft Acoustics

NASA Technical Reports Server (NTRS)

Bridges, James; Marino, Jodilyn

1999-01-01

The theory of mixer-ejectors for noise suppression is illustrated in this cartoon. Since jet noise SPL scales as velocity to the eighth power and diameter squared, increasing the jet diameter while lowering its velocity and keeping thrust constant decreases the noise. However, in supersonic craft, the drag penalty for increasing diameter at supersonic cruise makes this option very expensive. One would like to have a large engine during takeoff which could be shrunk during cruise. The retractable ejector is such an expandable engine. If the mixer flow can be expanded to the size of the ejector exit, the noise generated downstream of the ejector will be much less than the small diameter mixer nozzle alone. Of course, this also requires that the noise created in expanding the flow to fill the ejector be absorbed by a liner in the ejector walls so that none of this noise is heard. Since this mixing of internal hot gas and external cold air must take place in as short a distance as possible, the mixer must be very effective and therefore probably much noisier than a simple nozzle.

Shock Tube Test for Energy Absorbing Materials

DTIC Science & Technology

2013-09-13

rigid and lightweight foam material with a closed-cell structure, and a very high strength-to-weight ratio (7). It is commonly used as a sandwich...including application in helmet liners (8). Zorbium™ is the viscoelastic polyurethane foam used in military helmet suspension system pads (9). 8...viscoelastic polyurethane foam which shows strain rate dependent behavior when compressed. This is displayed by the significant difference in response

The Experimental Study about the Effect of Operating Conditions on Multi-tube Pulse Detonation Engine Performance

NASA Astrophysics Data System (ADS)

Kim, Jung-Min; Han, Hyung-Seok; Choi, Jeong-Yeol

2018-04-01

This study examines a multi-tube pulse detonation engine (PDE) which has a type of constant volume combustion. We designed and made the multi-tube PDE and then conducted an experiment in various operating frequencies and equivalence ratios. First, experiments with operating frequencies of 40, 80, 120, 160, and 200 Hz resulted in an average thrust and specific impulse 23.14 N and 42.34 s. The next experiment resulted in the equivalence ratio varying from 0.81 to 1.38, which resulted in an average thrust and specific impulse 22.36 N and 40.11 s. The average detonation velocity was 8% lower than that calculated according to C-J theory. The incidence ratios of the detonation wave were stable with the exception of the operating frequency of 200 Hz. However, at 200 Hz, the incidence ratio was less than 50%. We assumed that a low fill fraction occurred for this problem. The thrust of the PDE increased with the operating frequency. However, the thrust increase was at a lower rate than in previous studies, because of a lost thrust output result from the slow response time of the load cell amplifier.

Measurement of plasma momentum exerted on target by a small helicon plasma thruster and comparison with direct thrust measurement.

PubMed

Takahashi, Kazunori; Komuro, Atsushi; Ando, Akira

2015-02-01

Momentum, i.e., force, exerted from a small helicon plasma thruster to a target plate is measured simultaneously with a direct thrust measurement using a thrust balance. The calibration coefficient relating a target displacement to a steady-state force is obtained by supplying a dc to a calibration coil mounted on the target, where a force acting to a small permanent magnet located near the coil is directly measured by using a load cell. As the force exerted by the plasma flow to the target plate is in good agreement with the directly measured thrust, the validity of the target technique is demonstrated under the present operating conditions, where the thruster is operated in steady-state. Furthermore, a calibration coefficient relating a swing amplitude of the target to an impulse bit is also obtained by pulsing the calibration coil current. The force exerted by the pulsed plasma, which is estimated from the measured impulse bit and the pulse width, is also in good agreement with that obtained for the steady-state operation; hence, the thrust assessment of the helicon plasma thruster by the target is validated for both the steady-state and pulsed operations.

Experimental study on thrust and power of flapping-wing system based on rack-pinion mechanism.

PubMed

Nguyen, Tuan Anh; Vu Phan, Hoang; Au, Thi Kim Loan; Park, Hoon Cheol

2016-06-20

This experimental study investigates the effect of three parameters: wing aspect ratio (AR), wing offset, and flapping frequency, on thrust generation and power consumption of a flapping-wing system based on a rack-pinion mechanism. The new flapping-wing system is simple but robust, and is able to create a large flapping amplitude. The thrust measured by a load cell reveals that for a given power, the flapping-wing system using a higher wing AR produces larger thrust and higher flapping frequency at the wing offset of 0.15[Formula: see text] or 0.20[Formula: see text] ([Formula: see text] is the mean chord) than other wing offsets. Of the three parameters, the flapping frequency plays a more significant role on thrust generation than either the wing AR or the wing offset. Based on the measured thrusts, an empirical equation for thrust prediction is suggested, as a function of wing area, flapping frequency, flapping angle, and wing AR. The difference between the predicted and measured thrusts was less than 7%, which proved that the empirical equation for thrust prediction is reasonable. On average, the measured power consumption to flap the wings shows that 46.5% of the input power is spent to produce aerodynamic forces, 14.0% to overcome inertia force, 9.5% to drive the rack-pinion-based flapping mechanism, and 30.0% is wasted as the power loss of the installed motor. From the power analysis, it is found that the wing with an AR of 2.25 using a wing offset of 0.20[Formula: see text] showed the optimal power loading in the flapping-wing system. In addition, the flapping frequency of 25 Hz is recommended as the optimal frequency of the current flapping-wing system for high efficiency, which was 48.3%, using a wing with an AR of 2.25 and a wing offset of 0.20[Formula: see text] in the proposed design.

Combustor liner durability analysis

NASA Technical Reports Server (NTRS)

Moreno, V.

1981-01-01

An 18 month combustor liner durability analysis program was conducted to evaluate the use of advanced three dimensional transient heat transfer and nonlinear stress-strain analyses for modeling the cyclic thermomechanical response of a simulated combustor liner specimen. Cyclic life prediction technology for creep/fatigue interaction is evaluated for a variety of state-of-the-art tools for crack initiation and propagation. The sensitivity of the initiation models to a change in the operating conditions is also assessed.

Flap Side Edge Liners for Airframe Noise Reduction

NASA Technical Reports Server (NTRS)

Jones, Michael G. (Inventor); Khorrami, Mehdi R. (Inventor); Choudhari, Meelan M. (Inventor); Howerton, Brian M. (Inventor)

2014-01-01

One or more acoustic liners comprising internal chambers or passageways that absorb energy from a noise source on the aircraft are disclosed. The acoustic liners may be positioned at the ends of flaps of an aircraft wing to provide broadband noise absorption and/or dampen the noise producing unsteady flow features, and to reduce the amount of noise generated due to unsteady flow at the inboard and/or outboard end edges of a flap.

Test Method Designed to Evaluate Cylinder Liner-Piston Ring Coatings for Advanced Heat Engines

NASA Technical Reports Server (NTRS)

Radil, Kevin C.

1997-01-01

Research on advanced heat engine concepts, such as the low-heat-rejection engine, have shown the potential for increased thermal efficiency, reduced emissions, lighter weight, simpler design, and longer life in comparison to current diesel engine designs. A major obstacle in the development of a functional advanced heat engine is overcoming the problems caused by the high combustion temperatures at the piston ring/cylinder liner interface, specifically at top ring reversal (TRR). Therefore, advanced cylinder liner and piston ring materials are needed that can survive under these extreme conditions. To address this need, researchers at the NASA Lewis Research Center have designed a tribological test method to help evaluate candidate piston ring and cylinder liner materials for advanced diesel engines.

Free form hemispherical shaped charge

DOEpatents

Haselman, L.C. Jr.

1996-06-04

A hemispherical shaped charge has been modified such that one side of the hemisphere is spherical and the other is aspherical allowing a wall thickness variation in the liner. A further modification is to use an elongated hemispherical shape. The liner has a thick wall at its pole and a thin wall at the equator with a continually decreasing wall thickness from the pole to the equator. The ratio of the wall thickness from the pole to the equator varies depending on liner material and HE shape. Hemispherical shaped charges have previously been limited to spherical shapes with no variations in wall thicknesses. By redesign of the basic liner thicknesses, the jet properties of coherence, stability, and mass distribution have been significantly improved. 8 figs.

Free form hemispherical shaped charge

DOEpatents

Haselman, Jr., Leonard C.

1996-01-01

A hemispherical shaped charge has been modified such that one side of the hemisphere is spherical and the other is aspherical allowing a wall thickness variation in the liner. A further modification is to use an elongated hemispherical shape. The liner has a thick wall at its pole and a thin wall at the equator with a continually decreasing wall thickness from the pole to the equator. The ratio of the wall thickness from the pole to the equator varies depending on liner material and HE shape. Hemispherical shaped charges have previously been limited to spherical shapes with no variations in wall thicknesses. By redesign of the basic liner thicknesses, the jet properties of coherence, stability, and mass distribution have been significantly improved.

Test Stand at the Rocket Engine Test Facility

NASA Image and Video Library

1973-02-21

The thrust stand in the Rocket Engine Test Facility at the National Aeronautics and Space Administration (NASA) Lewis Research Center in Cleveland, Ohio. The Rocket Engine Test Facility was constructed in the mid-1950s to expand upon the smaller test cells built a decade before at the Rocket Laboratory. The $2.5-million Rocket Engine Test Facility could test larger hydrogen-fluorine and hydrogen-oxygen rocket thrust chambers with thrust levels up to 20,000 pounds. Test Stand A, seen in this photograph, was designed to fire vertically mounted rocket engines downward. The exhaust passed through an exhaust gas scrubber and muffler before being vented into the atmosphere. Lewis researchers in the early 1970s used the Rocket Engine Test Facility to perform basic research that could be utilized by designers of the Space Shuttle Main Engines. A new electronic ignition system and timer were installed at the facility for these tests. Lewis researchers demonstrated the benefits of ceramic thermal coatings for the engine’s thrust chamber and determined the optimal composite material for the coatings. They compared the thermal-coated thrust chamber to traditional unlined high-temperature thrust chambers. There were more than 17,000 different configurations tested on this stand between 1973 and 1976. The Rocket Engine Test Facility was later designated a National Historic Landmark for its role in the development of liquid hydrogen as a propellant.

Drone noise

NASA Astrophysics Data System (ADS)

Tinney, Charles; Sirohi, Jayant; University of Texas at Austin Team

2017-11-01

A basic understanding of the noise produced by single and multirotor drones operating at static thrust conditions is presented. This work acts as an extension to previous efforts conducted at The University of Texas at Austin (Tinney et al. 2017, AHS Forum 73). Propeller diameters ranging from 8 inch to 12 inch are examined for configurations comprising an isolated rotor, a quadcopter configuration and a hexacopter configuration, and with a constant drone pitch of 2.25. An azimuthal array of half-inch microphones, placed between 2 and 3 hub-center diameters from the drone center, are used to assess the acoustic near-field. Thrust levels, acquired using a six degree-of-freedom load cell, are then used to correlate acoustic noise levels to aerodynamic performance for each drone configuration. The findings reveal a nearly logarithmic increase in noise with increasing thrust. However, for the same thrust condition, considerable noise reduction is achieved by increasing the number of propeller blades thereby reducing the blade passage frequency and both the thickness and loading noise sources that accompany it.

Damping parameter study of a perforated plate with bias flow

NASA Astrophysics Data System (ADS)

Mazdeh, Alireza

One of the main impediments to successful operation of combustion systems in industrial and aerospace applications including gas turbines, ramjets, rocket motors, afterburners (augmenters) and even large heaters/boilers is the dynamic instability also known as thermo-acoustic instability. Concerns with this ongoing problem have grown with the introduction of Lean Premixed Combustion (LPC) systems developed to address the environmental concerns associated with the conventional combustion systems. The most common way to mitigate thermo-acoustic instability is adding acoustic damping to the combustor using acoustic liners. Recently damping properties of bias flow initially introduced to liners only for cooling purposes have been recognized and proven to be an asset in enhancing the damping effectiveness of liners. Acoustic liners are currently being designed using empirical design rules followed by build-test-improve steps; basically by trial and error. There is growing concerns on the lack of reliability associated with the experimental evaluation of the acoustic liners with small size apertures. The development of physics-based tools in assisting the design of such liners has become of great interest to practitioners recently. This dissertation focuses primarily on how Large-Eddy Simulations (LES) or similar techniques such as Scaled Adaptive Simulation (SAS) can be used to characterize damping properties of bias flow. The dissertation also reviews assumptions made in the existing analytical, semi-empirical, and numerical models, provides a criteria to rank order the existing models, and identifies the best existing theoretical model. Flow field calculations by LES provide good insight into the mechanisms that led to acoustic damping. Comparison of simulation results with empirical and analytical studies shows that LES simulation is a viable alternative to the empirical and analytical methods and can accurately predict the damping behavior of liners. Currently the role of LES for research studies concerned with damping properties of liners is limited to validation of other empirical or theoretical approaches. This research has shown that LES can go beyond that and can be used for performing parametric studies to characterize the sensitivity of acoustic properties of multi--perforated liners to the changes in the geometry and flow conditions and be used as a tool to design acoustic liners. The conducted research provides an insightful understanding about the contribution of different flow and geometry parameters such as perforated plate thickness, aperture radius, porosity factors and bias flow velocity. While the study agrees with previous observations obtained by analytical or experimental methods, it also quantifies the impact from these parameters on the acoustic impedance of perforated plate, a key parameter to determine the acoustic performance of any system. The conducted study has also explored the limitations and capabilities of commercial tool when are applied for performing simulation studies on damping properties of liners. The overall agreement between LES results and previous studies proves that commercial tools can be effectively used for these applications under certain conditions.

Cytotoxicity of Spent Pot Liner on Allium cepa root tip cells: A comparative analysis in meristematic cell type on toxicity bioassays.

PubMed

Palmieri, Marcel José; Andrade-Vieira, Larissa Fonseca; Campos, José Marcello Salabert; Dos Santos Gedraite, Leonardo; Davide, Lisete Chamma

2016-11-01

Spent Pot Liner (SPL) is a waste generated during the production of aluminum. It is comprised of a mixture of substances most of which, like cyanide, aluminum and fluoride, are toxic. Previous studies indicate the highly toxic nature of SPL. However studies using cells of the differentiation/elongation zone of the root meristem (referred as M2 cells in this study) after a proper recovery period in water were never considered. Using these cells could be useful to further understanding the toxicity mechanisms of SPL. A comparative approach between the effects on M2 cells and meristematic cells of the proximal meristem zone (referred as M1 cells in this study) could lead to understanding how DNA damage caused by SPL behaves on successive generations of cells. Allium cepa cells were exposed to 4 different concentrations of SPL (2.5, 5, 7.5 and 10gL(-1)) mixed with soil and diluted in a CaCl2 0.01M to simulate the ionic forces naturally encountered on the environment. A solution containing only soil diluted on CaCl2 0.01M was used as control. M1 and M2 cells were evaluated separately, taking into account four different parameters: (1) mitotic alterations (MA); (2) presence of condensed nuclei (CN); (3) mitotic index (MI); (4) presence of micronucleus (MCN). Significant differences were observed between M1 and M2 roots tip cells for these four parameters accessed. M1 cells was more prompt to reveal citogenotoxicity through the higher frequency of MA observed. Meanwhile, for M2 cells higher frequencies of MCN and CN was noticed, followed by a reduction of MI. Also, it was possible to detect significant differences between the tested treatments and the control on every case. These results indicate SPL toxic effects carries on to future cells generations. This emphasizes the need to properly manage this waste. Joint evaluation of cells from both M1 and M2 regions was proven valuable for the evaluation of a series of parameters on all toxicity tests. Copyright © 2016. Published by Elsevier Inc.

The Effect of Casting Ring Liner Length and Prewetting on the Marginal Adaptation and Dimensional Accuracy of Full Crown Castings.

PubMed

Haralur, Satheesh B; Hamdi, Osama A; Al-Shahrani, Abdulaziz A; Alhasaniah, Sultan

2017-01-01

To evaluate the effect of varying cellulose casting ring liner length and its prewetting on the marginal adaptation and dimensional accuracy of full veneer metal castings. The master die was milled in stainless steel to fabricate the wax pattern. Sixty wax patterns were fabricated with a uniform thickness of 1.5 mm at an occlusal surface and 1 mm axial surface, cervical width at 13.5 mm, and 10 mm cuspal height. The samples were divided into six groups ( n = 10). Groups I and II samples had the full-length cellulose prewet and dry ring liner, respectively. The groups III and IV had 2 mm short prewet and dry cellulose ring liner, respectively, whereas groups V and VI were invested in 6 mm short ring liner. The wax patterns were immediately invested in phosphate bonded investment, and casting procedure was completed with nickel-chrome alloy. The castings were cleaned and mean score of measurements at four reference points for marginal adaption, casting height, and cervical width was calculated. The marginal adaption was calculated with Imaje J software, whereas the casting height and cervical width was determined using a digital scale. The data was subjected to one-way analysis of varaince and Tukey post hoc statistical analysis with Statistical Package for the Social Sciences version 20 software. The group II had the best marginal adaption with a gap of 63.786 μm followed by group I (65.185 μm), group IV (87.740 μm), and group III (101.455 μm). A large marginal gap was observed in group V at 188.871 μm. Cuspal height was more accurate with group V (10.428 mm), group VI (10.421 mm), and group II (10.488 mm). The cervical width was approximately similar in group I, group III, and group V. Statistically significant difference was observed in Tukey post hoc analysis between group V and group VI with all the other groups with regards to marginal adaptation. The dry cellulose ring liners provided better marginal adaptation in comparison to prewet cellulose ring liners. Accurate cuspal height was obtained with shorter ring liner in comparison to full-length cellulose ring liners.

The Effect of Casting Ring Liner Length and Prewetting on the Marginal Adaptation and Dimensional Accuracy of Full Crown Castings

PubMed Central

Haralur, Satheesh B.; Hamdi, Osama A.; Al-Shahrani, Abdulaziz A.; Alhasaniah, Sultan

2017-01-01

Aim: To evaluate the effect of varying cellulose casting ring liner length and its prewetting on the marginal adaptation and dimensional accuracy of full veneer metal castings. Materials and Methods: The master die was milled in stainless steel to fabricate the wax pattern. Sixty wax patterns were fabricated with a uniform thickness of 1.5 mm at an occlusal surface and 1 mm axial surface, cervical width at 13.5 mm, and 10 mm cuspal height. The samples were divided into six groups (n = 10). Groups I and II samples had the full-length cellulose prewet and dry ring liner, respectively. The groups III and IV had 2 mm short prewet and dry cellulose ring liner, respectively, whereas groups V and VI were invested in 6 mm short ring liner. The wax patterns were immediately invested in phosphate bonded investment, and casting procedure was completed with nickel-chrome alloy. The castings were cleaned and mean score of measurements at four reference points for marginal adaption, casting height, and cervical width was calculated. The marginal adaption was calculated with Imaje J software, whereas the casting height and cervical width was determined using a digital scale. The data was subjected to one-way analysis of varaince and Tukey post hoc statistical analysis with Statistical Package for the Social Sciences version 20 software. Results: The group II had the best marginal adaption with a gap of 63.786 μm followed by group I (65.185 μm), group IV (87.740 μm), and group III (101.455 μm). A large marginal gap was observed in group V at 188.871 μm. Cuspal height was more accurate with group V (10.428 mm), group VI (10.421 mm), and group II (10.488 mm). The cervical width was approximately similar in group I, group III, and group V. Statistically significant difference was observed in Tukey post hoc analysis between group V and group VI with all the other groups with regards to marginal adaptation. Conclusion: The dry cellulose ring liners provided better marginal adaptation in comparison to prewet cellulose ring liners. Accurate cuspal height was obtained with shorter ring liner in comparison to full-length cellulose ring liners. PMID:28316950

Analysis of Fault Spacing in Thrust-Belt Wedges Using Numerical Modeling

NASA Astrophysics Data System (ADS)

Regensburger, P. V.; Ito, G.

2017-12-01

Numerical modeling is invaluable in studying the mechanical processes governing the evolution of geologic features such as thrust-belt wedges. The mechanisms controlling thrust fault spacing in wedges is not well understood. Our numerical model treats the thrust belt as a visco-elastic-plastic continuum and uses a finite-difference, marker-in-cell method to solve for conservation of mass and momentum. From these conservation laws, stress is calculated and Byerlee's law is used to determine the shear stress required for a fault to form. Each model consists of a layer of crust, initially 3-km-thick, carried on top of a basal décollement, which moves at a constant speed towards a rigid backstop. A series of models were run with varied material properties, focusing on the angle of basal friction at the décollement, the angle of friction within the crust, and the cohesion of the crust. We investigate how these properties affected the spacing between thrusts that have the most time-integrated history of slip and therefore have the greatest effect on the large-scale undulations in surface topography. The surface position of these faults, which extend through most of the crustal layer, are identifiable as local maxima in positive curvature of surface topography. Tracking the temporal evolution of faults, we find that thrust blocks are widest when they first form at the front of the wedge and then they tend to contract over time as more crustal material is carried to the wedge. Within each model, thrust blocks form with similar initial widths, but individual thrust blocks develop differently and may approach an asymptotic width over time. The median of thrust block widths across the whole wedge tends to decrease with time. Median fault spacing shows a positive correlation with both wedge cohesion and internal friction. In contrast, median fault spacing exhibits a negative correlation at small angles of basal friction (<17˚) and a positive correlation with larger angles of basal friction. From these correlations, we will derive scaling laws that can be used to predict fault spacing in thrust-belt wedges.

Effectiveness of a resin-modified glass ionomer liner in reducing hypersensitivity in posterior restorations: a study from the practitioners engaged in applied research and learning network.

PubMed

Strober, Brad; Veitz-Keenan, Analia; Barna, Julie Ann; Matthews, Abigail G; Vena, Donald; Craig, Ronald G; Curro, Frederick A; Thompson, Van P

2013-08-01

The objectives of this randomized comparative effectiveness study conducted by members of the Practitioners Engaged in Applied Research and Learning (PEARL) Network were to determine whether using a resin-modified glass ionomer (RMGI) liner reduces postoperative hypersensitivity (POH) in dentin-bonded Class I and Class II resin-based composite (RBC) restorations, as well as to identify other factors (putative risk factors) associated with increased POH. PEARL Network practitioner-investigators (P-Is) (n = 28) were trained to assess sensitivity determination, enamel and dentin caries activity rankings, evaluation for sleep bruxism, and materials and techniques used. The P-Is enrolled 341 participants who had hypersensitive posterior lesions. Participants were randomly assigned to receive an RBC restoration with or without an RMGI liner before P-Is applied a one-step, self-etching bonding agent. P-Is conducted sensitivity evaluations at baseline, at one and four weeks after treatment, and at all visits according to patient-reported outcomes. P-Is collected complete data regarding 347 restorations (339 participants) at baseline, with 341 (98 percent) (333 participants) recalled at four weeks. Treatment groups were balanced across baseline characteristics and measures. RBC restorations with or without an RMGI liner had the same one-week and four-week POH outcomes, as measured clinically (by means of cold or air stimulation) and according to patient-reported outcomes. Use of an RMGI liner did not reduce clinically measured or patient-reported POH in moderate-depth Class I and Class II restorations. Cold and air clinical stimulation findings were similar between groups. Practical Implications. The time, effort and expense involved in placing an RMGI liner in these moderate-depth RBC restorations may be unnecessary, as the representative liner used did not improve hypersensitivity outcomes.

A Three Month Comparative Evaluation of the Effect of Different Surface Treatment Agents on the Surface Integrity and Softness of Acrylic based Soft Liner: An In vivo Study

PubMed Central

Mahajan, Neerja; Naveen, Y. G.; Sethuraman, Rajesh

2017-01-01

Introduction Acrylic based soft liners are cost effective, yet are inferior in durability as compared to silicone based liners. Hence, this study was conducted to evaluate if the softness and surface integrity of acrylic based soft liner can be maintained by using different surface treatment agents. Aim To comparatively evaluate the effects of Varnish, Monopoly and Kregard surface treatment agents on the surface integrity and softness of acrylic based soft liner at baseline, at one month and after three months. Materials and Methods A total of 37 participants who required conventional maxillary dentures were selected according to the determined inclusion and exclusion criteria of the study. In the maxillary denture on the denture bearing surface, eight palatal recesses (5 mm x 3 mm) were made and filled with acrylic based soft liner (Permasoft). The soft liners in these recesses were given surface treatment and divided as control (uncoated), Varnish, Monopoly and Kregard groups. The hardness and surface integrity were evaluated with Shore A Durometer and Scanning Electron Microscope (SEM) respectively at baseline, one month and three months interval. Surface integrity between groups was compared using Kruskal-Wallis test. Intergroup comparison for hardness was done using ANOVA and Tukey’s HSD post-hoc tests. Results Amongst all the groups tested, surface integrity was maintained in the Kregard group, as compared to control, Varnish and Monopoly groups for all three time intervals (p< 0.001). Kregard treated samples also demonstrated significantly higher softness at all the time intervals (p<0.001). Conclusion Surface treatment with Kregard demonstrated better surface integrity and softness at all the time intervals. PMID:29207842

Probing off-Hugoniot states in Ta, Cu, and Al to 1000 GPa compression with magnetically driven liner implosions

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

Lemke, R. W., E-mail: rwlemke@sandia.gov; Dolan, D. H.; Dalton, D. G.

We report on a new technique for obtaining off-Hugoniot pressure vs. density data for solid metals compressed to extreme pressure by a magnetically driven liner implosion on the Z-machine (Z) at Sandia National Laboratories. In our experiments, the liner comprises inner and outer metal tubes. The inner tube is composed of a sample material (e.g., Ta and Cu) whose compressed state is to be inferred. The outer tube is composed of Al and serves as the current carrying cathode. Another aluminum liner at much larger radius serves as the anode. A shaped current pulse quasi-isentropically compresses the sample as itmore » implodes. The iterative method used to infer pressure vs. density requires two velocity measurements. Photonic Doppler velocimetry probes measure the implosion velocity of the free (inner) surface of the sample material and the explosion velocity of the anode free (outer) surface. These two velocities are used in conjunction with magnetohydrodynamic simulation and mathematical optimization to obtain the current driving the liner implosion, and to infer pressure and density in the sample through maximum compression. This new equation of state calibration technique is illustrated using a simulated experiment with a Cu sample. Monte Carlo uncertainty quantification of synthetic data establishes convergence criteria for experiments. Results are presented from experiments with Al/Ta, Al/Cu, and Al liners. Symmetric liner implosion with quasi-isentropic compression to peak pressure ∼1000 GPa is achieved in all cases. These experiments exhibit unexpectedly softer behavior above 200 GPa, which we conjecture is related to differences in the actual and modeled properties of aluminum.« less

Probing off-Hugoniot states in Ta, Cu, and Al to 1000 GPa compression with magnetically driven liner implosions

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

Lemke, R. W.; Dolan, D. H.; Dalton, D. G.

We report on a new technique for obtaining off-Hugoniot pressure vs. density data for solid metals compressed to extreme pressure by a magnetically driven liner implosion on the Z-machine (Z) at Sandia National Laboratories. In our experiments, the liner comprises inner and outer metal tubes. The inner tube is composed of a sample material (e.g., Ta and Cu) whose compressed state is to be inferred. The outer tube is composed of Al and serves as the current carrying cathode. Another aluminum liner at much larger radius serves as the anode. A shaped current pulse quasi-isentropically compresses the sample as itmore » implodes. The iterative method used to infer pressure vs. density requires two velocity measurements. Photonic Doppler velocimetry probes measure the implosion velocity of the free (inner) surface of the sample material and the explosion velocity of the anode free (outer) surface. These two velocities are used in conjunction with magnetohydrodynamic simulation and mathematical optimization to obtain the current driving the liner implosion, and to infer pressure and density in the sample through maximum compression. This new equation of state calibration technique is illustrated using a simulated experiment with a Cu sample. Monte Carlo uncertainty quantification of synthetic data establishes convergence criteria for experiments. Results are presented from experiments with Al/Ta, Al/Cu, and Al liners. Symmetric liner implosion with quasi-isentropic compression to peak pressure ~1000 GPa is achieved in all cases. Lastly, these experiments exhibit unexpectedly softer behavior above 200 GPa, which we conjecture is related to differences in the actual and modeled properties of aluminum.« less

UNVEILING THE PHYSICS OF LOW-LUMINOSITY AGNs THROUGH X-RAY VARIABILITY: LINER VERSUS SEYFERT 2

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

Hernández-García, L.; Masegosa, J.; Márquez, I.

X-ray variability is very common in active galactic nuclei (AGNs), but these variations may not occur similarly in different families of AGNs. We aim to disentangle the structure of low-ionization nuclear emission-line regions (LINERs) compared to Seyfert 2s by the study of their spectral properties and X-ray variations. We assembled the X-ray spectral parameters and variability patterns, which were obtained from simultaneous spectral fittings. Major differences are observed in the X-ray luminosities and the Eddington ratios, which are higher in Seyfert 2s. Short-term X-ray variations were not detected, while long-term changes are common in LINERs and Seyfert 2s. Compton-thick sourcesmore » generally do not show variations, most probably because the AGN is not accesible in the 0.5–10 keV energy band. The changes are mostly related to variations in the nuclear continuum, but other patterns of variability show that variations in the absorbers and at soft energies can be present in a few cases. We conclude that the X-ray variations may occur similarly in LINERs and Seyfert 2s, i.e., they are related to the nuclear continuum, although they might have different accretion mechanisms. Variations at UV frequencies are detected in LINER nuclei but not in Seyfert 2s. This is suggestive of at least some LINERs having an unobstructed view of the inner disk where the UV emission might take place, with UV variations being common in them. This result might be compatible with the disappeareance of the torus and/or the broad-line region in at least some LINERs.« less

Probing off-Hugoniot states in Ta, Cu, and Al to 1000 GPa compression with magnetically driven liner implosions

DOE PAGES

Lemke, R. W.; Dolan, D. H.; Dalton, D. G.; ...

2016-01-07

We report on a new technique for obtaining off-Hugoniot pressure vs. density data for solid metals compressed to extreme pressure by a magnetically driven liner implosion on the Z-machine (Z) at Sandia National Laboratories. In our experiments, the liner comprises inner and outer metal tubes. The inner tube is composed of a sample material (e.g., Ta and Cu) whose compressed state is to be inferred. The outer tube is composed of Al and serves as the current carrying cathode. Another aluminum liner at much larger radius serves as the anode. A shaped current pulse quasi-isentropically compresses the sample as itmore » implodes. The iterative method used to infer pressure vs. density requires two velocity measurements. Photonic Doppler velocimetry probes measure the implosion velocity of the free (inner) surface of the sample material and the explosion velocity of the anode free (outer) surface. These two velocities are used in conjunction with magnetohydrodynamic simulation and mathematical optimization to obtain the current driving the liner implosion, and to infer pressure and density in the sample through maximum compression. This new equation of state calibration technique is illustrated using a simulated experiment with a Cu sample. Monte Carlo uncertainty quantification of synthetic data establishes convergence criteria for experiments. Results are presented from experiments with Al/Ta, Al/Cu, and Al liners. Symmetric liner implosion with quasi-isentropic compression to peak pressure ~1000 GPa is achieved in all cases. Lastly, these experiments exhibit unexpectedly softer behavior above 200 GPa, which we conjecture is related to differences in the actual and modeled properties of aluminum.« less

Constraining the Accretion Mode in LINER 1.9s

NASA Astrophysics Data System (ADS)

Sabra, Bassem; Der Sahaguian, Elias; Badr, Elie

2016-01-01

The accretion mode and the dominant power source in low-ionization nuclear emission-line regions (LINERs), a class of active galactic nuclei (AGN), are still elusive. We focus on a sample of 22 LINER 1.9s (Ho et al. 1997), a subclass of LINERs that show broad Halpha lines, a signature of blackhole-powered accretion, to test the hypothesis that the ionizing continuum emitted by a radiatively inefficient accretion flow (RIAF) could lead to the LINER ultraviolet (UV) emission-line ratios. Optical line-ratio diagrams are a weak diagnostic tool in distinguishing between possible power sources (Sabra et al. 2003). We search the Mikulski Archive for Space Telescopes (MAST) for UV spectra of the objects in the above sample and also perform photoionization simulations using CLOUDY (Ferland et al. 2013). Unfortunately, only one object (NGC 1052; Gabel et al. 2000) of the 22 LINER 1.9s has UV spectra that cover many emission lines; the rest of the objects either do not have any UV spectra, the spectral coverage is in-adequate, or the spectra have very low signal-to-noise ratios. Our photoionization simulations set up two identical grids of clouds with a range of densities and ionization parameters. We illuminate one grid with radiation emitted by a thin accretion disk (AD) and we illuminate the other grid with radiation from a RIAF. We overplot the UV emission-line ratio predictions for AD and RIAF illumination, together with the available line ratios for NGC 1052. Initial results show that UV lines could be used as diagnostics for the accretion mode in AGN. More UV spectral coverage of LINER 1.9s is needed in order to more fully utilize the diagnostic powers of UV emission line ratios.

Implementation of In-Situ Impedance Techniques on a Full Scale Aero-Engine System

NASA Technical Reports Server (NTRS)

Gaeta, R. J.; Mendoza, J. M.; Jones, M. G.

2007-01-01

Determination of acoustic liner impedance for jet engine applications remains a challenge for the designer. Although suitable models have been developed that take account of source amplitude and the local flow environment experienced by the liner, experimental validation of these models has been difficult. This is primarily due to the inability of researchers to faithfully mimic the environment in jet engine nacelles in the laboratory. An in-situ measurement technique, one that can be implemented in an actual engine, is desirable so an accurate impedance can be determined for future modeling and quality control. This paper documents the implementation of such a local acoustic impedance measurement technique that is used under controlled laboratory conditions as well as on full scale turbine engine liner test article. The objective for these series of in-situ measurements is to substantiate treatment design, provide understanding of flow effects on installed liner performance, and provide modeling input for fan noise propagation computations. A series of acoustic liner evaluation tests are performed that includes normal incidence tube, grazing incidence tube, and finally testing on a full scale engine on a static test stand. Lab tests were intended to provide insight and guidance for accurately measuring the impedance of the liner housed in the inlet of a Honeywell Tech7000 turbofan. Results have shown that one can acquire very reasonable liner impedance data for a full scale engine under realistic test conditions. Furthermore, higher fidelity results can be obtained by using a three-microphone coherence technique that can enhance signal-to-noise ratio at high engine power settings. This research has also confirmed the limitations of this particular type of in-situ measurement. This is most evident in the installation of instrumentation and its effect on what is being measured.

Calibrated Mid-wave Infrared (IR) (MidIR) and Long-wave IR (LWIR) Stokes and Degree-of-Liner Polarization (DOLP)

DTIC Science & Technology

2008-09-01

LWIR long-wave IR MCT mercury cadmium telluride MidIR mid-wave IR NUC nonuniformity corrections ROI regions-of-interest 22 No. of Copies...Calibrated Mid-wave Infrared (IR) (MidIR) and Long-wave IR ( LWIR ) Stokes and Degree-of-Liner Polarization (DOLP) by Kristan P. Gurton and... LWIR ) Stokes and Degree-of-Liner Polarization (DOLP) Kristan P. Gurton and Melvin Felton Computational and Information Sciences Directorate

Single Common Powertrain Lubricant (SCPL) Development. Part 3

DTIC Science & Technology

2015-02-01

completed to assess the condition of the piston skirts, ring faces, and cylinder liners . This provides quasi-real time monitoring of the oils performance in...was most likely attributed to further scuffing of cylinder 2R. During the teardown and ratings at the end of testing, liner 2R was found to be 90...monitored and compared. The evaluated parameters of the test included the piston ring wear, cylinder liner wear, lead bearing corrosion, along with lubricant

KSC-02pd1273

NASA Image and Video Library

2002-08-28

KENNEDY SPACE CENTER, FLA. -- U.S. Sen. Bill Nelson congratulates Rick Beckwith, with the Flow Liner Inspection & Repair team. Nelson presented gold seal Senate certificates to the team for their work on finding the cracks in orbiter flow liners and repairing them. Other team members behind Nelson are Mike Young (center) and Jerry Gouding (right). Not pictured are Tony Nesotas and David Strait. Strait first spotted the fuel-line crack; Goudy performed arc welding on one of Atlantis' flow liners.

The absorption of sound by perforated linings

NASA Astrophysics Data System (ADS)

Hughes, I. J.; Dowling, A. P.

1990-09-01

This paper describes a practical application for sound-absorbent perforated screen with a bias flow through the screen. It is postulated that, if a perforated liner with a bias flow of cooling air through the liner is inserted in the afterburner section of a jet engine, all the incident sound may be absorbed at a particular frequency. Experimental results are presented on the absorptive properties of plane liners with circular apertures, showing an agreement with the theoretical model.

Extended use of the GuideLiner in complex coronary interventions.

PubMed

Chan, Pak Hei; Alegria-Barrero, Eduardo; Foin, Nicholas; Paulo, Manuel; Lindsay, Alistair C; Viceconte, Nicola; Di Mario, Carlo

2015-07-01

Challenging coronary anatomies including chronic total occlusions (CTO), extreme vessel tortuosity, diseased bypass grafts, and anomalous coronary arteries pose difficulties in coronary interventions. The GuideLiner is a monorail catheter originally developed to facilitate delivery of stents to target lesions in tortuous vessels. We conducted a study on the feasibility and safety of utilising this catheter in a wider array of complex coronary interventions. Consecutive patients undergoing coronary or peripheral interventions where a GuideLiner was used were recruited into this study. Patient demographics, lesion and vessel characteristics, procedural details and outcomes were prospectively entered into our database and analysed. From September 2009 to October 2011, 54 consecutive patients underwent coronary intervention in our institution using a GuideLiner; 21 out of 54 coronary applications were motivated by the need to increase support to cross CTOs, predominantly of the RCA. Anomalous or angulated take-off of the treatment vessels (31%), previously deployed proximal stents (15%), heavy proximal calcification (9%) and tortuosity (7%) accounted for the remaining reasons. One patient had successful renal denervation with the aid of a GuideLiner catheter. Procedural success was 98% in our series with no device-related periprocedural complications such as ostial dissection or myocardial necrosis. The use of a GuideLiner facilitates the approach to complex coronary interventions including chronic total occlusion and saphenous vein graft intervention by providing greater back-up support and easier engagement of coronary ostia.

Rapid Fabrication Techniques for Liquid Rocket Channel Wall Nozzles

NASA Technical Reports Server (NTRS)

Gradl, Paul R.

2016-01-01

The functions of a regeneratively-cooled nozzle are to (1) expand combustion gases to increase exhaust gas velocity while, (2) maintaining adequate wall temperatures to prevent structural failure, and (3) transfer heat from the hot gases to the coolant fluid to promote injector performance and stability. Regeneratively-cooled nozzles are grouped into two categories: tube-wall nozzles and channel wall nozzles. A channel wall nozzle is designed with an internal liner containing a series of integral coolant channels that are closed out with an external jacket. Manifolds are attached at each end of the nozzle to distribute coolant to and away from the channels. A variety of manufacturing techniques have been explored for channel wall nozzles, including state of the art laser-welded closeouts and pressure-assisted braze closeouts. This paper discusses techniques that NASA MSFC is evaluating for rapid fabrication of channel wall nozzles that address liner fabrication, slotting techniques and liner closeout techniques. Techniques being evaluated for liner fabrication include large-scale additive manufacturing of freeform-deposition structures to create the liner blanks. Abrasive water jet milling is being evaluated for cutting the complex coolant channel geometries. Techniques being considered for rapid closeout of the slotted liners include freeform deposition, explosive bonding and Cold Spray. Each of these techniques, development work and results are discussed in further detail in this paper.

With respect to coefficient of linear thermal expansion, bacterial vegetative cells and spores resemble plastics and metals, respectively.

PubMed

Nakanishi, Koichi; Kogure, Akinori; Fujii, Takenao; Kokawa, Ryohei; Deuchi, Keiji; Kuwana, Ritsuko; Takamatsu, Hiromu

2013-10-09

If a fixed stress is applied to the three-dimensional z-axis of a solid material, followed by heating, the amount of thermal expansion increases according to a fixed coefficient of thermal expansion. When expansion is plotted against temperature, the transition temperature at which the physical properties of the material change is at the apex of the curve. The composition of a microbial cell depends on the species and condition of the cell; consequently, the rate of thermal expansion and the transition temperature also depend on the species and condition of the cell. We have developed a method for measuring the coefficient of thermal expansion and the transition temperature of cells using a nano thermal analysis system in order to study the physical nature of the cells. The tendency was seen that among vegetative cells, the Gram-negative Escherichia coli and Pseudomonas aeruginosa have higher coefficients of linear expansion and lower transition temperatures than the Gram-positive Staphylococcus aureus and Bacillus subtilis. On the other hand, spores, which have low water content, overall showed lower coefficients of linear expansion and higher transition temperatures than vegetative cells. Comparing these trends to non-microbial materials, vegetative cells showed phenomenon similar to plastics and spores showed behaviour similar to metals with regards to the coefficient of liner thermal expansion. We show that vegetative cells occur phenomenon of similar to plastics and spores to metals with regard to the coefficient of liner thermal expansion. Cells may be characterized by the coefficient of linear expansion as a physical index; the coefficient of linear expansion may also characterize cells structurally since it relates to volumetric changes, surface area changes, the degree of expansion of water contained within the cell, and the intensity of the internal stress on the cellular membrane. The coefficient of linear expansion holds promise as a new index for furthering the understanding of the characteristics of cells. It is likely to be a powerful tool for investigating changes in the rate of expansion and also in understanding the physical properties of cells.

With respect to coefficient of linear thermal expansion, bacterial vegetative cells and spores resemble plastics and metals, respectively

PubMed Central

2013-01-01

Background If a fixed stress is applied to the three-dimensional z-axis of a solid material, followed by heating, the amount of thermal expansion increases according to a fixed coefficient of thermal expansion. When expansion is plotted against temperature, the transition temperature at which the physical properties of the material change is at the apex of the curve. The composition of a microbial cell depends on the species and condition of the cell; consequently, the rate of thermal expansion and the transition temperature also depend on the species and condition of the cell. We have developed a method for measuring the coefficient of thermal expansion and the transition temperature of cells using a nano thermal analysis system in order to study the physical nature of the cells. Results The tendency was seen that among vegetative cells, the Gram-negative Escherichia coli and Pseudomonas aeruginosa have higher coefficients of linear expansion and lower transition temperatures than the Gram-positive Staphylococcus aureus and Bacillus subtilis. On the other hand, spores, which have low water content, overall showed lower coefficients of linear expansion and higher transition temperatures than vegetative cells. Comparing these trends to non-microbial materials, vegetative cells showed phenomenon similar to plastics and spores showed behaviour similar to metals with regards to the coefficient of liner thermal expansion. Conclusions We show that vegetative cells occur phenomenon of similar to plastics and spores to metals with regard to the coefficient of liner thermal expansion. Cells may be characterized by the coefficient of linear expansion as a physical index; the coefficient of linear expansion may also characterize cells structurally since it relates to volumetric changes, surface area changes, the degree of expansion of water contained within the cell, and the intensity of the internal stress on the cellular membrane. The coefficient of linear expansion holds promise as a new index for furthering the understanding of the characteristics of cells. It is likely to be a powerful tool for investigating changes in the rate of expansion and also in understanding the physical properties of cells. PMID:24107328

One-dimensional radiation-hydrodynamic simulations of imploding spherical plasma liners with detailed equation-of-state modeling

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

Davis, J. S.; Hsu, S. C.; Golovkin, I. E.

2012-10-15

This work extends the one-dimensional radiation-hydrodynamic imploding spherical argon plasma liner simulations of Awe et al.[Phys. Plasmas 18, 072705 (2011)] by using a detailed tabular equation-of-state (EOS) model, whereas Awe et al. used a polytropic EOS model. Results using the tabular EOS model give lower stagnation pressures by a factor of 3.9-8.6 and lower peak ion temperatures compared to the polytropic EOS results. Both local thermodynamic equilibrium (LTE) and non-LTE EOS models were used in this work, giving similar results on stagnation pressure. The lower stagnation pressures using a tabular EOS model are attributed to a reduction in the liner'smore » ability to compress arising from the energy sink introduced by ionization and electron excitation, which are not accounted for in a polytropic EOS model. Variation of the plasma liner species for the same initial liner geometry, mass density, and velocity was also explored using the LTE tabular EOS model, showing that the highest stagnation pressure is achieved with the highest atomic mass species for the constraints imposed.« less

Optical fiber Bragg grating-instrumented silicone liner for interface pressure measurement within prosthetic sockets of lower-limb amputees

NASA Astrophysics Data System (ADS)

Al-Fakih, Ebrahim; Arifin, Nooranida; Pirouzi, Gholamhossein; Mahamd Adikan, Faisal Rafiq; Shasmin, Hanie Nadia; Abu Osman, Noor Azuan

2017-08-01

This paper presents a fiber Bragg grating (FBG)-instrumented prosthetic silicone liner that provides cushioning for the residual limb and can successfully measure interface pressures inside prosthetic sockets of lower-limb amputees in a simple and practical means of sensing. The liner is made of two silicone layers between which 12 FBG sensors were embedded at locations of clinical interest. The sensors were then calibrated using a custom calibration platform that mimics a real-life situation. Afterward, a custom gait simulating machine was built to test the liner performance during an amputee's simulated gait. To validate the findings, the results were compared to those obtained by the commonly used F-socket mats. As the statistical findings reveal, both pressure mapping methods measured the interface pressure in a consistent way, with no significant difference (P-values ≥0.05). This pressure mapping technique in the form of a prosthetic liner will allow prosthetics professionals to quickly and accurately create an overall picture of the interface pressure distribution inside sockets in research and clinical settings, thereby improving the socket fit and amputee's satisfaction.

Contoured-gap coaxial guns for imploding plasma liner experiments

NASA Astrophysics Data System (ADS)

Witherspoon, F. D.; Case, A.; Brockington, S.; Cassibry, J. T.; Hsu, S. C.

2014-10-01

Arrays of supersonic, high momentum flux plasma jets can be used as standoff compression drivers for generating spherically imploding plasma liners for driving magneto-inertial fusion, hence the name plasma-jet-driven MIF (PJMIF). HyperV developed linear plasma jets for the Plasma Liner Experiment (PLX) at LANL where two guns were successfully tested. Further development at HyperV resulted in achieving the PLX goal of 8000 μg at 50 km/s. Prior work on contoured-gap coaxial guns demonstrated an approach to control the blowby instability and achieved substantial performance improvements. For future plasma liner experiments we propose to use contoured-gap coaxial guns with small Minirailgun injectors. We will describe such a gun for a 60-gun plasma liner experiment. Discussion topics will include impurity control, plasma jet symmetry and topology (esp. related to uniformity and compactness), velocity capability, and techniques planned for achieving gun efficiency of >50% using tailored impedance matched pulse forming networks. Mach2 and UAH SPH code simulations will be included. Work supported by US DOE DE-FG02-05ER54810.

Plasma Liner Research for MTF at NASA Marshall Space Flight Center

NASA Technical Reports Server (NTRS)

Thio, Y. C. F.; Eskridge, R.; Lee, M.; Martin, A.; Smith, J.; Cassibry, J. T.; Wu, S. T.; Kirkpatrick, R. C.; Knapp, C. E.; Turchi, P. J.;

Diagnostic Techniques to Elucidate the Aerodynamic Performance of Acoustic Liners

NASA Technical Reports Server (NTRS)

June, Jason; Bertolucci, Brandon; Ukeiley, Lawrence; Cattafesta, Louis N., III; Sheplak, Mark

2017-01-01

In support of Topic A.2.8 of NASA NRA NNH10ZEA001N, the University of Florida (UF) has investigated the use of flow field optical diagnostic and micromachined sensor-based techniques for assessing the wall shear stress on an acoustic liner. Stereoscopic particle image velocimetry (sPIV) was used to study the velocity field over a liner in the Grazing Flow Impedance Duct (GFID). The results indicate that the use of a control volume based method to determine the wall shear stress is prone to significant error. The skin friction over the liner as measured using velocity curve fitting techniques was shown to be locally reduced behind an orifice, relative to the hard wall case in a streamwise plane centered on the orifice. The capacitive wall shear stress sensor exhibited a linear response for a range of shear stresses over a hard wall. PIV over the liner is consistent with lifting of the near wall turbulent structure as it passes over an orifice, followed by a region of low wall shear stress.

Graphite-fiber-reinforced polyimide liners of various compositions in plain spherical bearings

NASA Technical Reports Server (NTRS)

Sliney, H. E.; Jacobson, T. P.

1978-01-01

A plain spherical bearing design with a ball diameter of 28.6 mm, a race length of 12.7 mm, and a 1.7-mm-thick, molded composite liner was evaluated. The liner material is a self-lubricating composite of graphite-fiber-reinforced polyimide resin (GFRPI). The liner is prepared by transfer molding a mixture of one part chopped graphite fiber and one part partially polymerized resin into the space between the bearing ball and the outer race and then completing the polymerization under heat and pressure. Several liner compositions were evaluated: two types of polyimide, condensation and addition; two types of graphite fiber, low and high modulus; and four powder additives - cadmium oxide, cadmium iodide, graphite fluoride, and molybdenum disulfide. The bearings were oscillated + or - 15 deg at 1 Hz for 20 kilocycles under a radial unit load of 29 MN sq m (4200 psi) in dry air at 25, 200, or 315 C. Both types of fiber and polyimide gave low friction and wear. A simple equation was developed to fit the wear-time data and adequately predicted wear to 100 kilocycles.

Fracture Mechanics Analysis of LH2 Feed Line Flow Liners

NASA Technical Reports Server (NTRS)

James, Mark A.; Dawicke, David S.; Brzowski, Matthew B.; Raju, Ivatury S.; Elliott, Kenny B.; Harris, Charles E.

2006-01-01

Inspections of the Space Shuttle Main Engine revealed fatigue cracks growing from slots in the flow liner of the liquid hydrogen (LH2) feed lines. During flight, the flow liners experience complex loading induced by flow of LH2 and the resonance characteristics of the structure. The flow liners are made of Inconel 718 and had previously not been considered a fracture critical component. However, fatigue failure of a flow liner could have catastrophic effect on the Shuttle engines. A fracture mechanics study was performed to determine if a damage tolerance approach to life management was possible and to determine the sensitivity to the load spectra, material properties, and crack size. The load spectra were derived separately from ground tests and material properties were obtained from coupon tests. The stress-intensity factors for the fatigue cracks were determined from a shell-dynamics approach that simulated the dominant resonant frequencies. Life predictions were obtained using the NASGRO life prediction code. The results indicated that adequate life could not be demonstrated for initial crack lengths of the size that could be detected by traditional NDE techniques.

Summary of JAYGO mixing and FSM-1 application of castable inhibitor and liner

NASA Technical Reports Server (NTRS)

Evans, Kurt B.

1990-01-01

Two JAYGO planetary mixers (12 and 42 gallon) are being qualified to mix STW5-3224 liner and STW5-3223 castable inhibitor. These mixers are an integral part of a mix process which allows for safe addition of the asbestos component. An essential part of the engineering evaluation (ETP-0347) of these mixers is the generation of static test fire data. Ultimately, these results will help confirm the adequacy of these mixers for production mixing of liner and inhibitor. (These data are not required for qualification of the Certification Test Plan CTP-0125). The details on the mixing, inhibiting, and sling-lining of JAYGO-mixed castable inhibitor and liner which were applied to the FSM-1 segments are presented. The objectives are the following: (1) to document processing events surrounding the JAYO mixing of castable inhibitor and liner, and the subsequent inhibiting and sling lining onto the FSM-1 segments; and (2) to substantiate the measured properties of these JAYGO-mixed materials (rheological and mechanical) and compare these properties to existing production database.

MTF Driven by Plasma Liner Dynamically Formed by the Merging of Plasma Jets: An Overview

NASA Technical Reports Server (NTRS)

Thio, Y. C. Francis; Eskridge, Richard; Martin, Adam; Smith, James; Lee, Michael; Rodgers, Stephen L. (Technical Monitor)

2001-01-01

One approach for standoff delivery of the momentum flux for compressing the target in MTF consists of using a spherical array of plasma jets to form a spherical plasma shell imploding towards the center of a magnetized plasma, a compact toroid (Figure 1). A 3-year experiment (PLX-1) to explore the physics of forming a 2-D plasma liner (shell) by merging plasma jets is described. An overview showing how this 3-year project (PLX-1) fits into the program plan at the national and international level for realizing MTF for energy and propulsion is discussed. Assuming that there will be a parallel program in demonstrating and establishing the underlying physics principles of MTF using whatever liner is appropriate (e.g. a solid liner) with a goal of demonstrating breakeven by 2010, the current research effort at NASA MSFC attempts to complement such a program by addressing the issues of practical embodiment of MTF for propulsion. Successful conclusion of PLX-1 will be followed by a Physics Feasibility Experiment (PLX-2) for the Plasma Liner Driven MTF.

Comparison of Heavy-Duty Scuffing Behavior between Chromium-Based Ceramic Composite and Nickel-Chromium-Molybdenum-Coated Ring Sliding against Cast Iron Liner under Starvation

PubMed Central

Shen, Yan; Yu, Baihong; Lv, Yutao; Li, Bin

2017-01-01

A running-in and starved lubrication experiment is designed to investigate the heavy-duty scuffing behavior of piston ring coatings against cast iron (Fe) cylinder liner using the piston ring reciprocating liner test rig. The scuffing resistance of the piston ring with the chromium-based ceramic composite coating (CKS), and that with the thermally sprayed nickel-chromium-molybdenum coating (NCM) is compared at different nominal pressures (40~100 MPa) and temperatures (180~250 °C). With the failure time as a criterion, the rank order is as follows: NCM/Fe > CKS/Fe. Before the scoring occurs at the interface of the piston ring and cylinder liner (PRCL), the cast iron liner enters into a “polish wear” stage, and iron-based adhesive materials begin to form on the piston ring surface. With the macroscopic adhesion formation, the plastic shearing cycle causes surface damages mainly due to abrasive effects for the CKS/Fe pairs and adhesive effects for the NCM/Fe pairs. PMID:29036911

The Effect of External Magnetic Fields on the MRT Instability in MagLIF

NASA Astrophysics Data System (ADS)

Hess, Mark; Peterson, Kyle; Weis, Matthew; Lau, Yue Ying

2014-10-01

Recent experiments on MagLIF which incorporate an external B-field suggest that the MRT instability within the liner has a different behavior than without the B-field. Previous work by Chandrasekhar and Harris have illustrated how the MRT growth rate, assuming fixed liner density and fixed acceleration, can change due to the presence of an external B-field. In this work, we show how the growth rate of the MRT instability is dynamically affected by the rapidly varying acceleration, liner density, and surface magnetic field, which is composed of the external B-field and the drive B-field of the liner in the MagLIF experiments. In addition, we also examine the effects of finite liner resistivity on MRT growth, which gives rise to an additional time scale corresponding to magnetic diffusion. We discuss the implications of this result for future MagLIF designs. Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the United States Department of Energy under Contract DE-AC04-94AL85000.

Acoustic Liner Drag: Measurements on Novel Facesheet Perforate Geometries

NASA Technical Reports Server (NTRS)

Howerton, Brian M.; Jones, Michael G.

2016-01-01

Interest in characterization of the aerodynamic drag of acoustic liners has increased in the past several years. This paper details experiments in the NASA Langley Grazing Flow Impedance Tube to quantify the relative drag of several perforate-over-honeycomb liner configurations at flow speeds of centerline flow Mach number equals 0.3 and 0.5. Various perforate geometries and orientations are investigated to determine their resistance factors using a static pressure drop approach. Comparison of these resistance factors gives a relative measurement of liner drag. For these same flow conditions, acoustic measurements are performed with tonal excitation from 400 to 3000 hertz at source sound pressure levels of 140 and 150 decibels. Educed impedance and attenuation spectra are used to determine the impact of variations in perforate geometry on acoustic performance.

Transition duct system with straight ceramic liner for delivering hot-temperature gases in a combustion turbine engine

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

Wiebe, David J.

A transition duct system (10) for delivering hot-temperature gases from a plurality of combustors in a combustion turbine engine is provided. The system includes an exit piece (16) for each combustor. The exit piece may include a straight path segment (26) for receiving a gas flow from a respective combustor. A straight ceramic liner (40) may be inwardly disposed onto a metal outer shell (38) along the straight path segment of the exit piece. Structural arrangements are provided to securely attach the ceramic liner in the presence of substantial flow path pressurization. Cost-effective serviceability of the transition duct systems ismore » realizable since the liner can be readily removed and replaced as needed.« less

Operation and Performance Measurement on Engines in Sea Level Test Facilities

DTIC Science & Technology

1984-03-01

progressively larger collector to ’:7.. *: capture the efflux, but secondary airflow increases rapidly as collector area .-- increases. Therefore...1 + Dbm + Dc + Dts + Dbt - WeVe + (Pe - P 2 )Ae where the terms above and to follow are defined as Fa - measured thrust from load cell Pn - net thrust...Dbt - buoyancy (boat-tail) drag on exhaust nozzle. Considering that . (Pe-P" 2 )Ae + WeVe - (Pe-P..)Ae + (P-1-P- 2 )Ae + WeVe and .. .* Pg (Pe-PŖ)Ae

40 CFR 264.19 - Construction quality assurance program.

Code of Federal Regulations, 2011 CFR

2011-07-01

...) Geomembranes (flexible membrane liners); (v) Leachate collection and removal systems and leak detection systems... section; (ii) Proper construction of all components of the liners, leachate collection and removal system...

40 CFR 264.19 - Construction quality assurance program.

Code of Federal Regulations, 2012 CFR

2012-07-01

...) Geomembranes (flexible membrane liners); (v) Leachate collection and removal systems and leak detection systems... section; (ii) Proper construction of all components of the liners, leachate collection and removal system...

40 CFR 264.19 - Construction quality assurance program.

Code of Federal Regulations, 2014 CFR

2014-07-01

...) Geomembranes (flexible membrane liners); (v) Leachate collection and removal systems and leak detection systems... section; (ii) Proper construction of all components of the liners, leachate collection and removal system...

Hot Cell Liners Category of Transuranic Waste Stored Below Ground within Area G

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

Jones, Robert Wesley; Hargis, Kenneth Marshall

2014-09-01

A large wildfire called the Las Conchas Fire burned large areas near Los Alamos National Laboratory (LANL) in 2011 and heightened public concern and news media attention over transuranic (TRU) waste stored at LANL’s Technical Area 54 (TA-54) Area G waste management facility. The removal of TRU waste from Area G had been placed at a lower priority in budget decisions for environmental cleanup at LANL because TRU waste removal is not included in the March 2005 Compliance Order on Consent (Reference 1) that is the primary regulatory driver for environmental cleanup at LANL. The Consent Order is an agreementmore » between LANL and the New Mexico Environment Department (NMED) that contains specific requirements and schedules for cleaning up historical contamination at the LANL site. After the Las Conchas Fire, discussions were held by the U.S. Department of Energy (DOE) with the NMED on accelerating TRU waste removal from LANL and disposing it at the Waste Isolation Pilot Plant (WIPP). This report summarizes available information on the origin, configuration, and composition of the waste containers within the Hot Cell Liners category; their physical and radiological characteristics; the results of the radioassays; and the justification to reclassify the five containers as LLW rather than TRU waste.« less

Tensile properties from room temperature to 1315 C of tungsten-lined tantalum-alloy (T-111) tubing fabricated by hot isostatic pressing

NASA Technical Reports Server (NTRS)

Buzzard, R. J.; Metroka, R. R.

1974-01-01

The effects were studied of a thin tungsten liner on the tensile properties of T-111 tubing considered for fuel cladding in a space power nuclear reactor concept. The results indicate that the metallurgically bonded liner had no appreciable effects on the properties of the T-111 tubing. A hot isostatic pressing method used to apply the liners is described along with a means for overcoming the possible embrittling effects of hydrogen contamination.

Tokamak with liquid metal toroidal field coil

DOEpatents

Ohkawa, Tihiro; Schaffer, Michael J.

1981-01-01

Tokamak apparatus includes a pressure vessel for defining a reservoir and confining liquid therein. A toroidal liner disposed within the pressure vessel defines a toroidal space within the liner. Liquid metal fills the reservoir outside said liner. Electric current is passed through the liquid metal over a conductive path linking the toroidal space to produce a toroidal magnetic field within the toroidal space about the major axis thereof. Toroidal plasma is developed within the toroidal space about the major axis thereof.

Defeating the U-boat. Inventing Antisubmarine Warfare (Newport Papers Number 36)

DTIC Science & Technology

2010-08-01

did not explain how this number had been arrived at but claimed it could be achieved by no more than four cruisers and twelve armed liners in the...cover of darkness, ambush and destroy the largest unarmed liners afloat.33 Aube made clear that unlike in the past, ships, their crews, and cargoes...would not be captured but sunk without warning: “Having fol- lowed the liner from afar, come nightfall, the torpedo-boat will, perfectly silently and

Hydride reorientation and its impact on ambient temperature mechanical properties of high burn-up irradiated and unirradiated recrystallized Zircaloy-2 nuclear fuel cladding with an inner liner

NASA Astrophysics Data System (ADS)

Auzoux, Q.; Bouffioux, P.; Machiels, A.; Yagnik, S.; Bourdiliau, B.; Mallet, C.; Mozzani, N.; Colas, K.

2017-10-01

Precipitation of radial hydrides in zirconium-based alloy cladding concomitant with the cooling of spent nuclear fuel during dry storage can potentially compromise cladding integrity during its subsequent handling and transportation. This paper investigates hydride reorientation and its impact on ductility in unirradiated and irradiated recrystallized Zircaloy-2 cladding with an inner liner (cladding for boiling water reactors) subjected to hydride reorientation treatments. Cooling from 400 °C, hydride reorientation occurs in recrystallized Zircaloy-2 with liner at a lower effective stress in irradiated samples (below 40 MPa) than in unirradiated specimens (between 40 and 80 MPa). Despite significant hydride reorientation, unirradiated recrystallized Zircaloy-2 with liner cladding containing ∼200 wppm hydrogen shows a high diametral strain at fracture (>15%) during burst tests at ambient temperature. This ductile behavior is due to (1) the lower yield stress of the recrystallized cladding materials in comparison to hydride fracture strength (corrected by the compression stress arising from the precipitation) and (2) the hydride or hydrogen-depleted zone as a result of segregation of hydrogen into the liner layer. In irradiated Zircaloy-2 with liner cladding containing ∼340 wppm hydrogen, the conservation of some ductility during ring tensile tests at ambient temperature after reorientation treatment at 400 °C with cooling rates of ∼60 °C/h is also attributed to the existence of a hydride-depleted zone. Treatments at lower cooling rates (∼6 °C/h and 0.6 °C/h) promote greater levels of hydrogen segregation into the liner and allow for increased irradiation defect annealing, both of which result in a significant increase in ductility. Based on this investigation, given the very low cooling rates typical of dry storage systems, it can be concluded that the thermal transients associated with dry storage should not degrade, and more likely should actually improve, ductility of recrystallized Zircaloy-2 cladding with inner liner with such hydrogen content.

Extended MHD Effects in High Energy Density Experiments

NASA Astrophysics Data System (ADS)

Seyler, Charles

2016-10-01

The MHD model is the workhorse for computational modeling of HEDP experiments. Plasma models are inheritably limited in scope, but MHD is expected to be a very good model for studying plasmas at the high densities attained in HEDP experiments. There are, however, important ways in which MHD fails to adequately describe the results, most notably due to the omission of the Hall term in the Ohm's law (a form of extended MHD or XMHD). This talk will discuss these failings by directly comparing simulations of MHD and XMHD for particularly relevant cases. The methodology is to simulate HEDP experiments using a Hall-MHD (HMHD) code based on a highly accurate and robust Discontinuous Galerkin method, and by comparison of HMHD to MHD draw conclusions about the impact of the Hall term. We focus on simulating two experimental pulsed power machines under various scenarios. We examine the MagLIF experiment on the Z-machine at Sandia National Laboratories and liner experiments on the COBRA machine at Cornell. For the MagLIF experiment we find that power flow in the feed leads to low density plasma ablation into the region surrounding the liner. The inflow of this plasma compresses axial magnetic flux onto the liner. In MHD this axial flux tends to resistively decay, whereas in HMHD a force-free current layer sustains the axial flux on the liner leading to a larger ratio of axial to azimuthal flux. During the liner compression the magneto-Rayleigh-Taylor instability leads to helical perturbations due to minimization of field line bending. Simulations of a cylindrical liner using the COBRA machine parameters can under certain conditions exhibit amplification of an axial field due to a force-free low-density current layer separated by some distance from the liner. This results in a configuration in which there is predominately axial field on the liner inside the current layer and azimuthal field outside the layer. We are currently attempting to experimentally verify the simulation results. Collaborator: Nathaniel D. Hamlin, School of Electrical and Computer Engineering, Cornell University, Ithaca, New York.

Liquid balance monitoring inside conventional, Retrofit, and bio-reactor landfill cells

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

Abichou, Tarek, E-mail: abichou@eng.fsu.edu; Barlaz, Morton A.; Green, Roger

Highlights: • The Retrofit, Control, and As-Built cells received 48, 14, and 213 L Mg{sup −1} (liters of liquids per metric ton of waste). • The leachate collection system yielded 60, 57 and 198 L Mg{sup −1} from the Retrofit, Control, and As-Built cells. • The head on liner in all cells was below regulatory limits. • Measured moisture content of the waste samples was consistent with that calculated from accumulated liquid by balance. • The in-place saturated hydraulic conductivity of the MSW was calculated to be in the range of 10{sup −8} to 10{sup −7} m s{sup −1}. -more » Abstract: The Outer Loop landfill bioreactor (OLLB) in Louisville, KY, USA has been the site of a study to evaluate long-term bioreactor performance at a full-scale operational landfill. Three types of landfill units were studied including a conventional landfill (Control cell), a new landfill area that had an air addition and recirculation piping network installed as waste was being placed (As-Built cell), and a conventional landfill that was modified to allow for liquids recirculation (Retrofit cell). During the monitoring period, the Retrofit, Control, and As-Built cells received 48, 14, and 213 L Mg{sup −1} (liters of liquids per metric ton of waste), respectively. The leachate collection system yielded 60, 57 and 198 L Mg{sup −1} from the Retrofit, Control, and As-Built cells, respectively. The head on liner in all cells was below regulatory limits. In the Control and As-Built cells, leachate head on liner decreased once waste placement stopped. The measured moisture content of the waste samples was consistent with that calculated from the estimate of accumulated liquid by the liquid balance. Additionally, measurements on excavated solid waste samples revealed large spatial variability in waste moisture content. The degree of saturation in the Control cells decreased from 85% to 75%. The degree of saturation increased from 82% to 83% due to liquids addition in the Retrofit cells and decreased back to 80% once liquid addition stopped. In the As-Built cells, the degree of saturation increased from 87% to 97% during filling activities and then started to decrease soon after filling activities stopped to reach 92% at the end of the monitoring period. The measured leachate generation rates were used to estimate an in-place saturated hydraulic conductivity of the MSW in the range of 10{sup −8} to 10{sup −7} m s{sup −1} which is lower than previous reports. In the Control and Retrofit cells, the net loss in liquids, 43 and 12 L Mg{sup −1}, respectively, was similar to the measured settlement of 15% and 5–8% strain, respectively (Abichou et al., 2013). The increase in net liquid volume in the As-Built cells indicates that the 37% (average) measured settlement strain in these cells cannot be due to consolidation as the waste mass did not lose any moisture but rather suggests that settlement was attributable to lubrication of waste particle contacts, softening of flexible porous materials, and additional biological degradation.« less

Low thrust rocket test facility

NASA Technical Reports Server (NTRS)

Arrington, Lynn A.; Schneider, Steven J.

1990-01-01

A low thrust chemical rocket test facility has recently become operational at the NASA-Lewis. The new facility is used to conduct both long duration and performance tests at altitude over a thruster's operating envelope using hydrogen and oxygen gas for propellants. The facility provides experimental support for a broad range of objectives, including fundamental modeling of fluids and combustion phenomena, the evaluation of thruster components, and life testing of full rocket designs. The major mechanical and electrical systems are described along with aspects of the various optical diagnostics available in the test cell. The electrical and mechanical systems are designed for low down time between tests and low staffing requirements for test operations. Initial results are also presented which illustrate the various capabilities of the cell.

Survey of Technologies for Monitoring Containment Liners and Covers

EPA Pesticide Factsheets

The report provides information on innovative long-term monitoring technologies to detect contaminant releases beneath a liner containment system and identify potential problems with the integrity of final containment covers.