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Sample records for active compression test

  1. Compression test apparatus

    NASA Technical Reports Server (NTRS)

    Shanks, G. C. (Inventor)

    1981-01-01

    An apparatus for compressive testing of a test specimen may comprise vertically spaced upper and lower platen members between which a test specimen may be placed. The platen members are supported by a fixed support assembly. A load indicator is interposed between the upper platen member and the support assembly for supporting the total weight of the upper platen member and any additional weight which may be placed on it. Operating means are provided for moving the lower platen member upwardly toward the upper platen member whereby an increasing portion of the total weight is transferred from the load indicator to the test specimen.

  2. SNLL materials testing compression facility

    SciTech Connect

    Kawahara, W.A.; Brandon, S.L.; Korellis, J.S.

    1986-04-01

    This report explains software enhancements and fixture modifications which expand the capabilities of a servo-hydraulic test system to include static computer-controlled ''constant true strain rate'' compression testing on cylindrical specimens. True strains in excess of -1.0 are accessible. Special software features include schemes to correct for system compliance and the ability to perform strain-rate changes; all software for test control and data acquisition/reduction is documented.

  3. Extended testing of compression distillation.

    NASA Technical Reports Server (NTRS)

    Bambenek, R. A.; Nuccio, P. P.

    1972-01-01

    During the past eight years, the NASA Manned Spacecraft Center has supported the development of an integrated water and waste management system which includes the compression distillation process for recovering useable water from urine, urinal flush water, humidity condensate, commode flush water, and concentrated wash water. This paper describes the design of the compression distillation unit, developed for this system, and the testing performed to demonstrate its reliability and performance. In addition, this paper summarizes the work performed on pretreatment and post-treatment processes, to assure the recovery of sterile potable water from urine and treated urinal flush water.

  4. Compression and compression fatigue testing of composite laminates

    NASA Technical Reports Server (NTRS)

    Porter, T. R.

    1982-01-01

    The effects of moisture and temperature on the fatigue and fracture response of composite laminates under compression loads were investigated. The structural laminates studied were an intermediate stiffness graphite-epoxy composite (a typical angle ply laimna liminate had a typical fan blade laminate). Full and half penetration slits and impact delaminations were the defects examined. Results are presented which show the effects of moisture on the fracture and fatigue strength at room temperature, 394 K (250 F), and 422 K (300 F). Static tests results show the effects of defect size and type on the compression-fracture strength under moisture and thermal environments. The cyclic tests results compare the fatigue lives and residual compression strength under compression only and under tension-compression fatigue loading.

  5. Compression Testing of Alumina Fiber Insulation

    NASA Technical Reports Server (NTRS)

    Vaughn, Wallace L.

    2006-01-01

    A series of tests were conducted to measure the response of alumina fiber insulation to compression loading. The alumina fiber insulation is a candidate gasket material for the Space Shuttle Government Furnished Equipment (GFE) Tile Overlay Repair. Tests were conducted at room temperature and 2300 F. The alumina fiber insulation is a fibrous insulation blanket which was supplied to Langley in two forms, a nominal 3 lb/ft3 version and a nominal 9 lb/ft3 version. The 3 lb/ft3 material was tested as sheets 0.15 and 0.25 inches thick and the 9 lb/ft3 material in sheets 1 inch thick. The material showed very non-linear compression behavior with the compressive resistance of the material increasing as the material was compressed. The 3 lb/ft3 0.15-inch thick material required 4.1 psi to reach the nominal installation thickness of 0.045 inches and retain a load of 2.1 lbs during unloading. Testing at 2300 F resulted in a stiffer more board-like material. The 3 lb/ft3 0.15-inch thick material retained 1 psi of compressive resistance after a 10 minute hold at 2300 F and 0.045 inches thickness.

  6. Compression Testing of Textile Composite Materials

    NASA Technical Reports Server (NTRS)

    Masters, John E.

    1996-01-01

    The applicability of existing test methods, which were developed primarily for laminates made of unidirectional prepreg tape, to textile composites is an area of concern. The issue is whether the values measured for the 2-D and 3-D braided, woven, stitched, and knit materials are accurate representations of the true material response. This report provides a review of efforts to establish a compression test method for textile reinforced composite materials. Experimental data have been gathered from several sources and evaluated to assess the effectiveness of a variety of test methods. The effectiveness of the individual test methods to measure the material's modulus and strength is determined. Data are presented for 2-D triaxial braided, 3-D woven, and stitched graphite/epoxy material. However, the determination of a recommended test method and specimen dimensions is based, primarily, on experimental results obtained by the Boeing Defense and Space Group for 2-D triaxially braided materials. They evaluated seven test methods: NASA Short Block, Modified IITRI, Boeing Open Hole Compression, Zabora Compression, Boeing Compression after Impact, NASA ST-4, and a Sandwich Column Test.

  7. Compressed/reconstructed test images for CRAF/Cassini

    NASA Technical Reports Server (NTRS)

    Dolinar, S.; Cheung, K.-M.; Onyszchuk, I.; Pollara, F.; Arnold, S.

    1991-01-01

    A set of compressed, then reconstructed, test images submitted to the Comet Rendezvous Asteroid Flyby (CRAF)/Cassini project is presented as part of its evaluation of near lossless high compression algorithms for representing image data. A total of seven test image files were provided by the project. The seven test images were compressed, then reconstructed with high quality (root mean square error of approximately one or two gray levels on an 8 bit gray scale), using discrete cosine transforms or Hadamard transforms and efficient entropy coders. The resulting compression ratios varied from about 2:1 to about 10:1, depending on the activity or randomness in the source image. This was accomplished without any special effort to optimize the quantizer or to introduce special postprocessing to filter the reconstruction errors. A more complete set of measurements, showing the relative performance of the compression algorithms over a wide range of compression ratios and reconstruction errors, shows that additional compression is possible at a small sacrifice in fidelity.

  8. Uniaxial compression test series on Bullfrog Tuff

    SciTech Connect

    Price, R H; Jones, A K; Nimick, K G

    1982-04-01

    Nineteen uniaxial compressive experiments were performed on samples of the Bullfrog Member of the Crater Flat Tuff, obtained from drillhole USW-G1 at Yucca Mountain on the Nevada Test Site. The water saturated samples were deformed at a nominal strain rate of 10{sup -5} sec{sup -1}, atmospheric pressure and room temperature. Resultant unconfined compressive strengths, axial strains to failure, Young`s moduli and Poisson`s ratios ranged from 4.63 to 153. MPa, .0028 to .0058, 2.03 to 28.9 GPa and .08 to .16, respectively.

  9. Jig For Compression-Relaxation Tests Of Plastics

    NASA Technical Reports Server (NTRS)

    Shelley, Richard M.; Daniel, James A.; Tapphorn, Ralph M.

    1991-01-01

    Improved jig facilitates tests of long-term compression-relaxation properties of plastics. Holds specimen in compression when removed from compression-testing machine, yet allows compression force on specimen to be measured when on machine. Useful in quantifying some of time-dependent properties of polymers, in investigations of effects of aging, and in ascertaining service lifetimes of polymeric components.

  10. Acceptance Test Report for 241-U compressed air system

    SciTech Connect

    Freeman, R.D.

    1994-10-20

    This Acceptance Test Report (ATR) documents the results of acceptance testing of a newly upgraded compressed air system at 241-U Farm. The system was installed and the test successfully performed under work package 2W-92-01027.

  11. Leak-off tests help determine well bore compressibility

    SciTech Connect

    Hazov, V.A.; Hurshudov, V.A. )

    1993-11-29

    Well bore compressibility and hydraulically formed fractures can contribute to elastic well bore deformation in unstable shale formations. During leak-off tests in a basin near the Terek River in eastern North Caucasus in the former Soviet Union, the mud and well bores had anomalous, high compressibilities. Subsequent analyses indicated the system compressibility was related to elastic hydrofracture behavior, with the fracture being open without additional pressure applied at the surface. The paper discusses fluid compressibility, well bore deformation, the leak-off tests, and similar problems which occurred in the Maikop shales in the eastern North Caucasus.

  12. Apparatus for elevated temperature compression or tension testing of specimens

    NASA Astrophysics Data System (ADS)

    Gates, Thomas S.

    1992-05-01

    In order to support materials selection for the next generation supersonic civilian passenger transport aircraft, a testing apparatus was developed to evaluate certain materials under conditions of high load and elevated temperature. In order to elevate the temperature of the material during standard tension and compression testing the test specimen is surrounded by a pair of supports which include internal heating means. These supports also prevent buckling of the specimen during compression testing.

  13. Impact testing of ductile cast iron: Tension and compression

    SciTech Connect

    Yokoyama, T.; Takata, T.; Sogabe, Y.

    1995-11-01

    Impact tension and compression tests on ferritic ductile cast iron (JIS FCD370) are conducted by means of the split Hopkinson bar technique. Reliable stress-strain relations in tension and compression for ductile cast iron are determined at strain rates of over 10{sup 3}/s. The test results indicate that ductile cast iron shows different strength characteristics in tension and compression under impact loading as well as under quasi-static loading. Microscopic examinations of the post-test specimens reveal that this mechanical behavior is attributed to the presence of spheroidal graphites in a ferritic matrix of ductile cast iron.

  14. An Architecture of Embedded Decompressor with Reconfigurability for Test Compression

    NASA Astrophysics Data System (ADS)

    Ichihara, Hideyuki; Saiki, Tomoyuki; Inoue, Tomoo

    Test compression/decompression scheme for reducing the test application time and memory requirement of an LSI tester has been proposed. In the scheme, the employed coding algorithms are tailored to a given test data, so that the tailored coding algorithm can highly compress the test data. However, these methods have some drawbacks, e. g., the coding algorithm is ineffective in extra test data except for the given test data. In this paper, we introduce an embedded decompressor that is reconfigurable according to coding algorithms and given test data. Its reconfigurability can overcome the drawbacks of conventional decompressors with keeping high compression ratio. Moreover, we propose an architecture of reconfigurable decompressors for four variable-length codings. In the proposed architecture, the common functions for four codings are implemented as fixed (or non-reconfigurable) components so as to reduce the configuration data, which is stored on an ATE and sent to a CUT. Experimental results show that (1) the configuration data size becomes reasonably small by reducing the configuration part of the decompressor, (2) the reconfigurable decompressor is effective for SoC testing in respect of the test data size, and (3) it can achieve an optimal compression of test data by Huffman coding.

  15. Research priorities and history of advanced composite compression testing

    NASA Technical Reports Server (NTRS)

    Baumann, K. J.

    1981-01-01

    Priorities for standard compression testing research in advanced laminated fibrous composite materials are presented along with a state of the art survey (completed in 1979) including history and commentary on industrial test methods. Historically apparent research priorities and consequent (lack of) progress are supporting evidence for newly derived priorities.

  16. Active RF Pulse Compression Using An Electrically Controlled Semiconductor Switch

    SciTech Connect

    Guo, Jiquan; Tantawi, Sami; /SLAC

    2007-01-10

    First we review the theory of active pulse compression systems using resonant delay lines. Then we describe the design of an electrically controlled semiconductor active switch. The switch comprises an active window and an overmoded waveguide three-port network. The active window is based on a four-inch silicon wafer which has 960 PIN diodes. These are spatially combined in an overmoded waveguide. We describe the philosophy and design methodology for the three-port network and the active window. We then present the results of using this device to compress 11.4 GHz RF signals with high compression ratios. We show how the system can be used with amplifier like sources, in which one can change the phase of the source by manipulating the input to the source. We also show how the active switch can be used to compress a pulse from an oscillator like sources, which is not possible with passive pulse compression systems.

  17. Compressive Testing of Stitched Frame and Stringer Alternate Configurations

    NASA Technical Reports Server (NTRS)

    Leone, Frank A., Jr.; Jegley, Dawn C.

    2016-01-01

    A series of single-frame and single-stringer compression tests were conducted at NASA Langley Research Center on specimens harvested from a large panel built using the Pultruded Rod Stitched Efficient Unitized Structure (PRSEUS) concept. Different frame and stringer designs were used in fabrication of the PRSEUS panel. In this report, the details of the experimental testing of single-frame and single-stringer compression specimens are presented, as well as discussions on the performance of the various structural configurations included in the panel.

  18. Test patterns and quality metrics for digital video compression

    NASA Astrophysics Data System (ADS)

    Fenimore, Charles P.; Field, Bruce F.; Van Degrift, Craig

    1997-06-01

    Lossy video compression systems such as MPEG2 introduce picture impairments such as image blocking, color distortion and persistent color fragments, 'mosquito noise,' and blurring in their outputs. While there are video test clips which exhibit one or more of these distortions upon coding, there is need of a set of well-characterized test patterns and video quality metrics. Digital test patterns can deliver calibrated stresses to specific features of the encoder, much as the test patterns for analog video stress critical characteristics of that system. Metrics quantify the error effects of compression by a computation. NIST is developing such test patterns and metrics for compression rates that typically introduce perceptually negligible artifacts, i.e. for high quality video. The test patterns are designed for subjective and objective evaluation. The test patterns include a family of computer-generated spinning wheels to stress luminance-based macro-block motion estimation algorithms and images with strongly directional high-frequency content to stress quantization algorithms. In this paper we discuss the spinning wheel test pattern. It has been encoded at a variety of bit rates near the threshold for the perception of impairments. We have observed that impairment perceptibility depends on the local contrast. For the spinning wheel we report the contrast at the threshold for perception of impairments as a function of the bit rate. To quantify perceptual image blocking we have developed a metric which detects 'flats:' image blocks of constant (or near constant) luminance. The effectiveness of this metric is appraised.

  19. Test Compression for Robust Testable Path Delay Fault Testing Using Interleaving and Statistical Coding

    NASA Astrophysics Data System (ADS)

    Namba, Kazuteru; Ito, Hideo

    This paper proposes a method providing efficient test compression. The proposed method is for robust testable path delay fault testing with scan design facilitating two-pattern testing. In the proposed method, test data are interleaved before test compression using statistical coding. This paper also presents test architecture for two-pattern testing using the proposed method. The proposed method is experimentally evaluated from several viewpoints such as compression rates, test application time and area overhead. For robust testable path delay fault testing on 11 out of 20 ISCAS89 benchmark circuits, the proposed method provides better compression rates than the existing methods such as Huffman coding, run-length coding, Golomb coding, frequency-directed run-length (FDR) coding and variable-length input Huffman coding (VIHC).

  20. Impact tests on rubber compression springs for airplane landing gears

    NASA Technical Reports Server (NTRS)

    Hohenemser, K

    1930-01-01

    The present report gives the results of tests which were made for the purpose of solving the problem of whether diagrams obtained from pressure tests could be conclusive for the determination of the safe impact coefficients. It is first established that the rubber rings adhere firmly to the compression surfaces during deformation. Suggestions are thus obtained for a constructive simplification of the rubber rings. The hysteresis phenomenon is ascribed to external and internal friction forces. A device for falling tests is then described with which the process of shock absorption with rubber rings was tested.

  1. Insulation interlaminar shear strength testing with compression and irradiation

    SciTech Connect

    McManamy, T.J.; Brasier, J.E.; Snook, P.; Idaho National Engineering Lab., Idaho Falls, ID; Princeton Univ., NJ )

    1989-01-01

    The Compact Ignition Tokamak (CIT) project identified the need for research and development for the insulation to be used in the toroidal field coils. The requirements included tolerance to a combination of high compression and shear and a high radiation dose. Samples of laminate-type sheet material were obtained from commercial vendors. The materials included various combinations of epoxy, polyimide, E-glass, S-glass, and T-glass. The T-glass was in the form of a three-dimensional weave. The first tests were with 50 {times} 25 {times} 1 mm samples. These materials were loaded in compression and then to failure in shear. At 345-MPa compression, the interlaminar shear strength was generally in the range of 110 to 140 MPa for the different materials. A smaller sample configuration was developed for irradiation testing. The data before irradiation were similar to those for the larger samples but approximately 10% lower. Limited fatigue testing was also performed by cycling the shear load. No reduction in shear strength was found after 50,000 cycles at 90% of the failure stress. Because of space limitations, only three materials were chosen for irradiation: two polyimide systems and one epoxy system. All used boron-free glass. The small shear/compression samples and some flexure specimens were irradiated to 4 {times} 10{sup 9} and 2 {times} 10{sup 10} rad in the Advanced Technology Reactor at Idaho National Engineering Laboratory. A lead shield was used to ensure that the majority of the dose was from neutrons. The shear strength with compression before and after irradiation at the lower dose was determined. Flexure strength and the results from irradiation at the higher dose level will be available in the near future. 7 refs., 7 figs., 2 tabs.

  2. Operability test procedure for 241-U compressed air system and heat pump

    SciTech Connect

    Freeman, R.D.

    1994-08-31

    The 241-U-701 compressed air system supplies instrument quality compressed air to Tank Farm 241-U. The supply piping to the 241-U Tank Farm is not included in the modification. Modifications to the 241-U-701 compressed air system include installation of a 15 HP Reciprocating Air Compressor, Ingersoll-Rand Model 10T3NLM-E15; an air dryer, Hankinson, Model DH-45; and miscellaneous system equipment and piping (valves, filters, etc.) to meet the design. A newly installed heat pump allows the compressor to operate within an enclosed relatively dust free atmosphere and keeps the compressor room within a standard acceptable temperature range, which makes possible efficient compressor operation, reduces maintenance, and maximizes compressor operating life. This document is an Operability Test Procedure (OTP) which will further verify (in addition to the Acceptance Test Procedure) that the 241-U-701 compressed air system and heat pump operate within their intended design parameters. The activities defined in this OTP will be performed to ensure the performance of the new compressed air system will be adequate, reliable and efficient. Completion of this OTP and sign off of the OTP Acceptance of Test Results is necessary for turnover of the compressed air system from Engineering to Operations.

  3. Explosive Flux Compression: 50 Years of Los Alamos Activities

    SciTech Connect

    Fowler, C.M.; Thomson, D.B.; Garn, W.B.

    1998-10-18

    Los Alamos flux compression activities are surveyed, mainly through references in view of space limitations. However, two plasma physics programs done with Sandia National Laboratory are discussed in more detail.

  4. Pulse code modulation data compression for automated test equipment

    SciTech Connect

    Navickas, T.A.; Jones, S.G.

    1991-05-01

    Development of automated test equipment for an advanced telemetry system requires continuous monitoring of PCM data while exercising telemetry inputs. This requirements leads to a large amount of data that needs to be stored and later analyzed. For example, a data stream of 4 Mbits/s and a test time of thirty minutes would yield 900 Mbytes of raw data. With this raw data, information needs to be stored to correlate the raw data to the test stimulus. This leads to a total of 1.8 Gb of data to be stored and analyzed. There is no method to analyze this amount of data in a reasonable time. A data compression method is needed to reduce the amount of data collected to a reasonable amount. The solution to the problem was data reduction. Data reduction was accomplished by real time limit checking, time stamping, and smart software. Limit checking was accomplished by an eight state finite state machine and four compression algorithms. Time stamping was needed to correlate stimulus to the appropriate output for data reconstruction. The software was written in the C programming language with a DOS extender used to allow it to run in extended mode. A 94--98% compression in the amount of data gathered was accomplished using this method. 1 fig.

  5. Hydrogen ICE Vehicle Testing Activities

    SciTech Connect

    J. Francfort; D. Karner

    2006-04-01

    The Advanced Vehicle Testing Activity teamed with Electric Transportation Applications and Arizona Public Service to develop and monitor the operations of the APS Alternative Fuel (Hydrogen) Pilot Plant. The Pilot Plant provides 100% hydrogen, and hydrogen and compressed natural gas (H/CNG)-blended fuels for the evaluation of hydrogen and H/CNG internal combustion engine (ICE) vehicles in controlled and fleet testing environments. Since June 2002, twenty hydrogen and H/CNG vehicles have accumulated 300,000 test miles and 5,700 fueling events. The AVTA is part of the Department of Energy’s FreedomCAR and Vehicle Technologies Program. These testing activities are managed by the Idaho National Laboratory. This paper discusses the Pilot Plant design and monitoring, and hydrogen ICE vehicle testing methods and results.

  6. High strain rate compression testing of glass fibre reinforced polypropylene

    NASA Astrophysics Data System (ADS)

    Govender, R. A.; Langdon, G. S.; Cloete, T. J.; Nurick, G. N.

    2012-08-01

    This paper details an investigation of the high strain rate compression testing of GFPP with the Split Hopkinson Pressure Bar (SHPB) in the through-thickness and in-plane directions. GFPP posed challenges to SHPB testing as it fails at relatively high stresses, while having relatively low moduli and hence mechanical impedance. The modifications to specimen geometry and incident pulse shaping in order to gather valid test results, where specimen equilibrium was achieved for SHPB tests on GFPP are presented. In addition to conventional SHPB tests to failure, SHPB experiments were designed to achieve specimen equilibration at small strains, which permitted the capture of high strain rate elastic modulus data. The strain rate dependency of GFPP's failure strengths in the in-plane and through-thickness direction is modelled using a logarithmic law.

  7. Compression mass gauge testing in a liquid hydrogen dewar

    NASA Technical Reports Server (NTRS)

    Jurns, J. M.; Rogers, A. C.

    1995-01-01

    This paper describes testing that was conducted using a mass gauge in a liquid hydrogen environment. The mass gauge, herein referred to as the 'compressibility gauge,' is being developed as a means to accurately determine the mass of liquid contained in a tank in a low-gravity environment. The concept is based on the thermodynamic principle that the pressure of gas or vapor changes when its volume changes. Previous work has been conducted by Southwest Research Institute in collaboration with NASA Lewis Research Center. This consisted of testing the concept with water and other cryogenic simulant fluids. The purpose of conducting liquid hydrogen tests is to test the concept in actual cryogenic conditions, and address hardware issues that arise in fabricating a test article for use in liquid hydrogen.

  8. Method of testing very soft biological tissues in compression.

    PubMed

    Miller, Karol

    2005-01-01

    Mechanical properties of very soft tissues, such as brain, liver, kidney and prostate have recently joined the mainstream research topics in biomechanics. This has happened in spite of the fact that these tissues do not bear mechanical loads. The interest in the biomechanics of very soft tissues has been motivated by the developments in computer-integrated and robot-aided surgery--in particular, the emergence of automatic surgical tools and robots-as well as advances in virtual reality techniques. Mechanical testing of very soft tissues provides a formidable challenge for an experimenter. Very soft tissues are usually tested in compression using an unconfined compression set-up, which requires ascertaining that friction between sample faces and stress-strain machine platens is close to zero. In this paper a more reliable method of testing is proposed. In the proposed method top and bottom faces of a cylindrical specimen with low aspect ratio are rigidly attached to the platens of the stress-strain machine (e.g. using surgical glue). This arrangement allows using a no-slip boundary condition in the analysis of the results. Even though the state of deformation in the sample cannot be treated as orthogonal the relationships between total change of height (measured) and strain are obtained. Two important results are derived: (i) deformed shape of a cylindrical sample subjected to uniaxial compression is independent on the form of constitutive law, (ii) vertical extension in the plane of symmetry lambda(z) is proportional to the total change of height for strains as large as 30%. The importance and relevance of these results to testing procedures in biomechanics are highlighted. PMID:15519351

  9. Compressive tensile and shear testing of melt-foamed aluminium

    SciTech Connect

    Von Hagen, H.; Bleck, W.

    1998-12-31

    For construction purposes it is utterly important to get detailed information on the possible influence of the foam thickness on the mechanical properties and on the deformation behavior of metallic foams. The effect of compressive, tensile and shear loads on aluminium foam samples has been examined with the testing methods for sandwich material as described in German and ASTM-standards. The aim is to provide more data on these mechanical properties varying the sample density and thickness. Regarding the results the most reliable material parameters as well as steps towards a relationship between the different strength parameters can be obtained.

  10. Compression After Impact Testing of Sandwich Structures Using the Four Point Bend Test

    NASA Technical Reports Server (NTRS)

    Nettles, Alan T.; Gregory, Elizabeth; Jackson, Justin; Kenworthy, Devon

    2008-01-01

    For many composite laminated structures, the design is driven by data obtained from Compression after Impact (CAI) testing. There currently is no standard for CAI testing of sandwich structures although there is one for solid laminates of a certain thickness and lay-up configuration. Most sandwich CAI testing has followed the basic technique of this standard where the loaded ends are precision machined and placed between two platens and compressed until failure. If little or no damage is present during the compression tests, the loaded ends may need to be potted to prevent end brooming. By putting a sandwich beam in a four point bend configuration, the region between the inner supports is put under a compressive load and a sandwich laminate with damage can be tested in this manner without the need for precision machining. Also, specimens with no damage can be taken to failure so direct comparisons between damaged and undamaged strength can be made. Data is presented that demonstrates the four point bend CAI test and is compared with end loaded compression tests of the same sandwich structure.

  11. Development of a biaxial compression test apparatus for granular materials

    NASA Astrophysics Data System (ADS)

    Zhang, Lian-Wei; Zhang, Jian-Min

    2013-06-01

    A set of two-dimensional biaxial compression testing system was developed to investigate the stress-strain behavior and its change with the micro-structure of granular materials. The specimen was assembled using small metal bars with elliptical section. Load was then subjected in both horizontal and vertical directions. Three different stress paths could be realized, including constant lateral pressure, constant mean principal stress and constant principal stress ratio. A non-invasive measurement method using digital image correlation analysis was developed. The displacement of each particle in the specimen could be traced. As a result, the displacement field of each specimen and its microstructure evolution during loading process could be measured. The testing system was applied in monotonic shear tests for two-dimensional assemblies of metal bars with different size, showing its essential effectiveness for the investigation of the micro-structure change and mechanical behavior.

  12. Effective Size Analysis of the Diametral Compression (Brazil) Test Specimen

    SciTech Connect

    Jadaan, Osama M.; Wereszczak, Andrew A

    2009-04-01

    This study considers the finite element analysis (FEA) simulation and Weibull effective size analysis for the diametral compression (DC) or Brazil specimen loaded with three different push-rod geometries. Those geometries are a flat push-rod, a push-rod whose radius of curvature is larger than that for the DC specimen, and a push-rod whose radius of curvature matches that of the DC specimen. Such established effective size analysis recognizes that the tensile strength of structural ceramics is typically one to two orders of magnitude less than its compressive strength. Therefore, because fracture is much more apt to result from a tensile stress than a compressive one, this traditional analysis only considers the first principal tensile stress field in the mechanically loaded ceramic component for the effective size analysis. The effective areas and effective volumes were computed as function of Weibull modulus using the CARES/Life code. Particular attention was devoted to the effect of mesh sensitivity and localized stress concentration. The effect of specimen width on the stress state was also investigated. The effects of push-rod geometry, the use of steel versus WC push-rods, and considering a frictionless versus no-slip interface between push-rod and specimen on the maximum stresses, where those stresses are located, and the effective area and effective volume results are described. Of the three push-rod geometries, it is concluded that the push-rod (made from WC rather than steel) whose radius of curvature matches that of the DC specimen is the most apt to cause fracture initiation within the specimen's bulk rather than at the loading interface. Therefore, its geometry is the most likely to produce a valid diametral compression strength test. However, the DC specimen remains inefficient in terms of its area and volume efficiencies; namely, the tensile strength of only a few percent of the specimen's entire area or volume is sampled. Given the high probability

  13. Characterizing the compression-dependent viscoelastic properties of human hepatic pathologies using dynamic compression testing

    NASA Astrophysics Data System (ADS)

    DeWall, Ryan J.; Bharat, Shyam; Varghese, Tomy; Hanson, Meghan E.; Agni, Rashmi M.; Kliewer, Mark A.

    2012-04-01

    Recent advances in elastography have provided several imaging modalities capable of quantifying the elasticity of tissue, an intrinsic tissue property. This information is useful for determining tumour margins and may also be useful for diagnosing specific tumour types. In this study, we used dynamic compression testing to quantify the viscoelastic properties of 16 human hepatic primary and secondary malignancies and their corresponding background tissue obtained following surgical resection. Two additional backgrounds were also tested. An analysis of the background tissue showed that F4-graded fibrotic liver tissue was significantly stiffer than F0-graded tissue, with a modulus contrast of 4:1. Steatotic liver tissue was slightly stiffer than normal liver tissue, but not significantly so. The tumour-to-background storage modulus contrast of hepatocellular carcinomas, a primary tumour, was approximately 1:1, and the contrast decreased with increasing fibrosis grade of the background tissue. Ramp testing showed that the background stiffness increased faster than the malignant tissue. Conversely, secondary tumours were typically much stiffer than the surrounding background, with a tumour-to-background contrast of 10:1 for colon metastases and 10:1 for cholangiocarcinomas. Ramp testing showed that colon metastases stiffened faster than their corresponding backgrounds. These data have provided insights into the mechanical properties of specific tumour types, which may prove beneficial as the use of quantitative stiffness imaging increases.

  14. Calibration of DEM simulation: Unconfined Compressive Test and Brazilian Tensile Test

    NASA Astrophysics Data System (ADS)

    Wang, Yucang; Alonso-Marroquín, Fernando

    2009-06-01

    We simulate rock fracture using ESyS_Particle, which is a 3-D Discrete Element Model developed for modeling geological materials. Two types of simulations are carried out: Unconfined Compressive Test (UCT) and Brazilian Tensile Test (BTT). The results are compared to laboratory tests. Model parameters are determined on the basis of theoretical studies on the elastic properties of regular lattices and dimensionless analysis. The fracture patterns and realistic macroscopic strength are well reproduced. Also the ratio of the macroscopic strength of compression to the tensile strength is obtained numerically.

  15. Tensile and compressive test results for metal matrix composites

    NASA Technical Reports Server (NTRS)

    Shuart, M. J.; Herakovich, C. T.

    1977-01-01

    Experimental results of the mechanical behavior of two metal matrix composite systems at room temperature are presented. Ultimate stress, ultimate strain, Poisson's ratio, and initial Young's Modulus are documented for BORSIC/Aluminum in uniaxial tension and Boron/Aluminum in uniaxial tension and compression. Poisson's ratio is used for nonlinear stress-strain behavior. A comparison of compression results for B/Al as obtained from sandwich beam compression specimens and IITRI coupon compression specimens is presented.

  16. Numerical Simulations of the Kolsky Compression Bar Test

    SciTech Connect

    Corona, Edmundo

    2015-10-01

    The Kolsky compression bar, or split Hopkinson pressure bar (SHPB), is an ex- perimental apparatus used to obtain the stress-strain response of material specimens at strain rates in the order of 10 2 to 10 4 1/s. Its operation and associated data re- duction are based on principles of one-dimensional wave propagation in rods. Second order effects such as indentation of the bars by the specimen and wave dispersion in the bars, however, can significantly affect aspects of the measured material response. Finite element models of the experimental apparatus were used here to demonstrate these two effects. A procedure proposed by Safa and Gary (2010) to account for bar indentation was also evaluated and shown to improve the estimation of the strain in the bars significantly. The use of pulse shapers was also shown to alleviate the effects of wave dispersion. Combining the two can lead to more reliable results in Kolsky compression bar testing.

  17. Design and Testing of CO2 Compression Using Supersonic Shock Wave Technology

    SciTech Connect

    Koopman, Aaron

    2015-06-01

    This report summarizes work performed by Ramgen and subcontractors in pursuit of the design and construction of a 10 MW supersonic CO2 compressor and supporting facility. The compressor will demonstrate application of Ramgen’s supersonic compression technology at an industrial scale using CO2 in a closed-loop. The report includes details of early feasibility studies, CFD validation and comparison to experimental data, static test experimental results, compressor and facility design and analyses, and development of aerodynamic tools. A summary of Ramgen's ISC Engine program activity is also included. This program will demonstrate the adaptation of Ramgen's supersonic compression and advanced vortex combustion technology to result in a highly efficient and cost effective alternative to traditional gas turbine engines. The build out of a 1.5 MW test facility to support the engine and associated subcomponent test program is summarized.

  18. A dynamic ball compression test for understanding rock crushing.

    PubMed

    Huang, S; Liu, H; Xia, K

    2014-12-01

    During crushing, rock particles are subjected to complicated loading. It is desired to establish the relation between the loading and the fragmentation parameters for better understanding rock crushing mechanism. In this work, a split Hopkinson pressure bar system in combination with high speed cameras is utilized in the dynamic ball compression test, in which the spherical rock sample is adopted to avoid the shape effect. Using elasticity theory, the loading rate and the dynamic indirect tensile strength are first calculated. With the aid of the moment-trap technique and high speed cameras, the surface energy is determined for each sample. The relations between the loading rate and the fragmentation parameters, i.e., the number of fragments and the surface energy are established. The application of this method to a granitic rock shows that it is flexible and can be applied to the crushing study of generic brittle solids. PMID:25554304

  19. High-Strain-Rate Compression Testing of Ice

    NASA Technical Reports Server (NTRS)

    Shazly, Mostafa; Prakash, Vikas; Lerch, Bradley A.

    2006-01-01

    In the present study a modified split Hopkinson pressure bar (SHPB) was employed to study the effect of strain rate on the dynamic material response of ice. Disk-shaped ice specimens with flat, parallel end faces were either provided by Dartmouth College (Hanover, NH) or grown at Case Western Reserve University (Cleveland, OH). The SHPB was adapted to perform tests at high strain rates in the range 60 to 1400/s at test temperatures of -10 and -30 C. Experimental results showed that the strength of ice increases with increasing strain rates and this occurs over a change in strain rate of five orders of magnitude. Under these strain rate conditions the ice microstructure has a slight influence on the strength, but it is much less than the influence it has under quasi-static loading conditions. End constraint and frictional effects do not influence the compression tests like they do at slower strain rates, and therefore the diameter/thickness ratio of the samples is not as critical. The strength of ice at high strain rates was found to increase with decreasing test temperatures. Ice has been identified as a potential source of debris to impact the shuttle; data presented in this report can be used to validate and/or develop material models for ice impact analyses for shuttle Return to Flight efforts.

  20. Descriptor for spatial distribution of motion activity for compressed video

    NASA Astrophysics Data System (ADS)

    Divakaran, Ajay; Sun, Huifang

    1999-12-01

    In this paper we present a new descriptor for spatial distribution of motion activity in video sequences. We use the magnitude of the motion vectors as a measure of the intensity of motion cavity in a macro-block. We construct a matrix Cmv consisting of the magnitudes of the motion vector for each macro-block of a given P frame. We compute the average magnitude of the motion vector per macro-block Cavg, and then use Cavg as a threshold on the matrix C by setting the elements of C that are less than Cavg to zero. We classify the runs of zeros into three categories based on length, and count the number of runs of each category in the matrix C. Our activity descriptor for a frame thus consists of four parameters viz. the average magnitude of the motion vectors and the numbers of runs of short, medium and long length. Since the feature extraction is in the compressed domain and simple, it is extremely fast. We have tested it on the MPEG-7 test content set, which consists of approximately 14 hours of MPEG-1 encoded video content of different kinds. We find that our descriptor enables fast and accurate indexing of video. It is robust to noise and changes in encoding parameters such as frame size, frame rate, encoding bit rate, encoding format etc. It is a low-level non-semantic descriptor that gives semantic matches within the same program, and is thus very suitable for applications such as video program browsing. We also find that indirect and computationally simpler measures of the magnitude of the motion vectors such as bits taken to encode the motion vectors, though less effective, also can be used in our run-length framework.

  1. High-Speed Photography during Compression Testing Human Trabecular Bone

    NASA Astrophysics Data System (ADS)

    Thurner, Philipp; Langan, John; Erickson, Blake

    2005-03-01

    The mechanical properties of healthy and diseased bone are extensively studied. Most of this research is motivated by the immense costs in health care due to osteoporosis. To address the problem of assessing bone microarchitecture and concomitant microcracking behavior, we recently combined mechanical compression testing of trabecular bone with high-speed photography. In an exemplary study, we investigated healthy, osteoarthritic, and osteoporotic human vertebral trabecular bone. Bone samples were loaded along their principal load-bearing axis at high strain rates simulating boundary conditions as experienced in individuals during falls. Even at small global strains huge local deformations could be seen in the recorded high-speed photography frames. Moreover, strained trabeculae were seen to whiten with increasing strain, which could be associated with areas of high deformation using a motion energy filter. Presumably the effect seen is due to microcrack formation in these areas, similar to stress whitening in synthetic polymers. This hypothesis is currently tested applying en bloc microcrack staining and histology.

  2. A method for intermediate strain rate compression testing and study of compressive failure mechanism of Mg-Al-Zn alloy

    NASA Astrophysics Data System (ADS)

    Gupta, Nikhil; Luong, Dung D.; Rohatgi, Pradeep K.

    2011-05-01

    Obtaining meaningful information from the test results is a challenge in the split-Hopkinson pressure bar (SHPB) test method if the specimen does not fail during the test. Although SHPB method is now widely used for high strain rate testing, this limitation has made it difficult to use it for characterization of materials in the intermediate strain rate range (typically 10-1000 s-1). In the present work, a method is developed to characterize materials in the intermediate strain rate range using SHPB setup. In this method, the specimen is repeatedly tested under compression at a given strain rate until failure is achieved. The stress-strain graphs obtained from each test cycle are used to plot the master stress-strain graph for that strain rate. This method is used to study the strain rate dependence of compressive response of a Mg-Al-Zn alloy in the intermediate strain rate range. A remarkable difference is observed in the failure mechanism of the alloy under quasi-static and intermediate strain rate compression. Matrix cracking is the main failure mechanism under quasi-static compression, whereas shattering of intermetallic precipitates, along with plastic deformation of the matrix, is discovered to become prominent as the strain rate is increased.

  3. Monocytic Cells Become Less Compressible but More Deformable upon Activation

    PubMed Central

    Ravetto, Agnese; Wyss, Hans M.; Anderson, Patrick D.; den Toonder, Jaap M. J.; Bouten, Carlijn V. C.

    2014-01-01

    Aims Monocytes play a significant role in the development of atherosclerosis. During the process of inflammation, circulating monocytes become activated in the blood stream. The consequent interactions of the activated monocytes with the blood flow and endothelial cells result in reorganization of cytoskeletal proteins, in particular of the microfilament structure, and concomitant changes in cell shape and mechanical behavior. Here we investigate the full elastic behavior of activated monocytes in relation to their cytoskeletal structure to obtain a better understanding of cell behavior during the progression of inflammatory diseases such as atherosclerosis. Methods and Results The recently developed Capillary Micromechanics technique, based on exposing a cell to a pressure difference in a tapered glass microcapillary, was used to measure the deformation of activated and non-activated monocytic cells. Monitoring the elastic response of individual cells up to large deformations allowed us to obtain both the compressive and the shear modulus of a cell from a single experiment. Activation by inflammatory chemokines affected the cytoskeletal organization and increased the elastic compressive modulus of monocytes with 73–340%, while their resistance to shape deformation decreased, as indicated by a 25–88% drop in the cell’s shear modulus. This decrease in deformability is particularly pronounced at high strains, such as those that occur during diapedesis through the vascular wall. Conclusion Overall, monocytic cells become less compressible but more deformable upon activation. This change in mechanical response under different modes of deformation could be important in understanding the interplay between the mechanics and function of these cells. In addition, our data are of direct relevance for computational modeling and analysis of the distinct monocytic behavior in the circulation and the extravascular space. Lastly, an understanding of the changes of monocyte

  4. Numerical evaluation of the capping tendency of microcrystalline cellulose tablets during a diametrical compression test.

    PubMed

    Furukawa, Ryoichi; Chen, Yuan; Horiguchi, Akio; Takagaki, Keisuke; Nishi, Junichi; Konishi, Akira; Shirakawa, Yoshiyuki; Sugimoto, Masaaki; Narisawa, Shinji

    2015-09-30

    Capping is one of the major problems that occur during the tabletting process in the pharmaceutical industry. This study provided an effective method for evaluating the capping tendency during diametrical compression test using the finite element method (FEM). In experiments, tablets of microcrystalline cellulose (MCC) were compacted with a single tabletting machine, and the capping tendency was determined by visual inspection of the tablet after a diametrical compression test. By comparing the effects of double-radius and single-radius concave punch shapes on the capping tendency, it was observed that the capping tendency of double-radius tablets occurred at a lower compaction force compared with single-radius tablets. Using FEM, we investigated the variation in plastic strain within tablets during the diametrical compression test and visualised it using the output variable actively yielding (AC YIELD) of ABAQUS. For both single-radius and double-radius tablets, a capping tendency is indicated if the variation in plastic strain was initiated from the centre of tablets, while capping does not occur if the variation began from the periphery of tablets. The compaction force estimated by the FEM analysis at which the capping tendency was observed was in reasonable agreement with the experimental results. PMID:26188313

  5. Defect dynamics and ordering in compressible active nematics

    NASA Astrophysics Data System (ADS)

    Mishra, Prashant; Srivastava, Pragya; Marchetti, M. Cristina

    Active nematics, such as suspensions of biopolymers activated by molecular motors or bacteria swimming in passive liquid crystals, exhibit complex self-sustained flow, excitability and defect generation. Activity renders the defect themselves self-propelled particles, capable of organizing in emergent ordered structures. We have developed a minimal model of compressible active nematics on a substrate. We eliminate the flow velocity in favor of the nematic order parameter via the balance of frictional dissipation and active driving to obtain a dynamical description entirely in terms of the nematic alignment order parameter. Activity renormalizes the bend and splay elastic constants rendering them anisotropic and driving them to zero or even negative, resulting in the appearance of modulated states and defective structures. Using linear stability analysis and numerics we organize the various regimes into a phase diagram and discuss the relation to experiments. This work was supported by NSF-DMR-1305184.

  6. Trunk Muscle Activation and Estimating Spinal Compressive Force in Rope and Harness Vertical Dance.

    PubMed

    Wilson, Margaret; Dai, Boyi; Zhu, Qin; Humphrey, Neil

    2015-12-01

    Rope and harness vertical dance takes place off the floor with the dancer suspended from his or her center of mass in a harness attached to a rope from a point overhead. Vertical dance represents a novel environment for training and performing in which expected stresses on the dancer's body are different from those that take place during dance on the floor. Two male and eleven female dancers with training in vertical dance performed six typical vertical dance movements with electromyography (EMG) electrodes placed bilaterally on rectus abdominus, external oblique, erector spinae, and latissimus dorsi. EMG data were expressed as a percentage of maximum voluntary isometric contraction (MVIC). A simplified musculoskeletal model based on muscle activation for these four muscle groups was used to estimate the compressive force on the spine. The greatest muscle activation for erector spinae and latissimus dorsi and the greatest trunk compressive forces were seen in vertical axis positions where the dancer was moving the trunk into a hyper-extended position. The greatest muscle activation for rectus abdominus and external oblique and the second highest compressive force were seen in a supine position with the arms and legs extended away from the center of mass (COM). The least muscle activation occurred in positions where the limbs were hanging below the torso. These movements also showed relatively low muscle activation compression forces. Post-test survey results revealed that dancers felt comfortable in these positions; however, observation of some positions indicated insufficient muscular control. Computing the relative contribution of muscles, expressed as muscle activation and estimated spinal compression, provided a measure of how much the muscle groups were working to support the spine and the rest of the dancer's body in the different movements tested. Additionally, identifying typical muscle recruitment patterns in each movement will help identify key exercises

  7. Three-dimensional active imaging using compressed gating

    NASA Astrophysics Data System (ADS)

    Dai, Huidong; He, Weiji; Miao, Zhuang; Chen, Yunfei; Gu, Guohua

    2013-09-01

    Due to the numerous applications employed 3D data such as target detection and recognition, three-dimensional (3D) active imaging draws great interest recently. Employing a pulsed laser as the illumination source and an intensified sensor as the image sensor, the 3D active imaging method emits and then records laser pulses to infer the distance between the target and the sensor. One of the limitations of the 3D active imaging is that acquiring depth map with high depth resolution requires a full range sweep, as well as a large number of detections, which limits the detection speed. In this work, a compressed gating method combining the 3D active imaging and compressive sensing (CS) is proposed on the basis of the random gating method to achieve the depth map reconstruction from a significantly reduced number of detections. Employing random sequences to control the sensor gate, this method estimates the distance and reconstructs the depth map in the framework of CS. A simulation was carried out to estimate the performance of the proposed method. A scene generated by the 3ds Max was employed as target and a reconstruction algorithm was used to recover the depth map in the simulation. The simulation results have shown that the proposed method can reconstruct the depth map with slight reconstruction error using as low as 7% detections that the conventional method requires and achieve perfect reconstruction from about 10% detections under the same depth resolution. It has also indicated that the number of detections required is affected by depth resolution, noise generated by a variety of reasons and complexity of the target scene. According to the simulation results, the compressed gating method is able to be used in the case of long range with high depth resolution and robust to various types of noise. In addition, the method is able to be used for multiple-return signals measurement without increase in the number of detections.

  8. Green and early age compressive strength of extruded cement mortar monitored with compression tests and ultrasonic techniques

    SciTech Connect

    Voigt, Thomas . E-mail: mail@tvoigt.com; Malonn, Tim; Shah, Surendra P.

    2006-05-15

    Knowledge about the early age compressive strength development of cementitious materials is an important factor for the progress and safety of many construction projects. This paper uses cylindrical mortar specimens produced with a ram extruder to investigate the transition of the mortar from plastic and deformable to hardened state. In addition, wave transmission and reflection measurements with P- and S-waves were conducted to obtain further information about the microstructural changes during the setting and hardening process. The experiments have shown that uniaxial compression tests conducted on extruded mortar cylinders are a useful tool to evaluate the green strength as well as the initiation and further development of the compressive strength of the tested material. The propagation of P-waves was found to be indicative of the internal structure of the tested mortars as influenced, for example, by the addition of fine clay particles. S-waves used in transmission and reflection mode proved to be sensitive to the inter-particle bonding caused by the cement hydration and expressed by an increase in compressive strength.

  9. Compressive strength of dental composites photo-activated with different light tips

    NASA Astrophysics Data System (ADS)

    Galvão, M. R.; Caldas, S. G. F. R.; Calabrez-Filho, S.; Campos, E. A.; Bagnato, V. S.; Rastelli, A. N. S.; Andrade, M. F.

    2013-04-01

    The aim of this study was to evaluate the compressive strength of microhybrid (Filtek™ Z250) and nanofilled (Filtek™ Supreme XT) composite resins photo-activated with two different light guide tips, fiber optic and polymer, coupled with one LED. The power density was 653 mW cm-2 when using the fiber optic light tip and 596 mW cm-2 with the polymer. After storage in distilled water at 37 ± 2 °C for seven days, the samples were subjected to mechanical testing of compressive strength in an EMIC universal mechanical testing machine with a load cell of 5 kN and speed of 0.5 mm min-1. The statistical analysis was performed using ANOVA with a confidence interval of 95% and Tamhane’s test. The results showed that the mean values of compressive strength were not influenced by the different light tips (p > 0.05). However, a statistical difference was observed (p < 0.001) between the microhybrid composite resin photo-activated with the fiber optic light tip and the nanofilled composite resin. Based on these results, it can be concluded that microhybrid composite resin photo-activated with the fiber optic light tip showed better results than nanofilled, regardless of the tip used, and the type of the light tip did not influence the compressive strength of either composite. Thus, the presented results suggest that both the fiber optic and polymer light guide tips provide adequate compressive strength to be used to make restorations. However, the fiber optic light tip associated with microhybrid composite resin may be an interesting option for restorations mainly in posterior teeth.

  10. A Test Data Compression Scheme Based on Irrational Numbers Stored Coding

    PubMed Central

    Wu, Hai-feng; Cheng, Yu-sheng; Zhan, Wen-fa; Cheng, Yi-fei; Wu, Qiong; Zhu, Shi-juan

    2014-01-01

    Test question has already become an important factor to restrict the development of integrated circuit industry. A new test data compression scheme, namely irrational numbers stored (INS), is presented. To achieve the goal of compress test data efficiently, test data is converted into floating-point numbers, stored in the form of irrational numbers. The algorithm of converting floating-point number to irrational number precisely is given. Experimental results for some ISCAS 89 benchmarks show that the compression effect of proposed scheme is better than the coding methods such as FDR, AARLC, INDC, FAVLC, and VRL. PMID:25258744

  11. A technique for combined dynamic compression-shear test

    NASA Astrophysics Data System (ADS)

    Zhao, P. D.; Lu, F. Y.; Chen, R.; Lin, Y. L.; Li, J. L.; Lu, L.; Sun, G. L.

    2011-03-01

    It is critically important to study the dynamic response of materials under a combined compression-shear loading for developing constitutive laws more accurately and fully. We present a novel technique to achieve the combined compression and shear loadings at high strain rates. The main apparatus consists of a strike bar, an incident bar, and two transmission bars. The close-to-specimen end of the incident bar is wedge-shaped with 90°. In each experiment, there are two identical specimens, respectively, agglutinated between one side of the wedge and one of transmission bars. When a loading impulse travels to specimens along the incident bar, because of the special geometrical shape, the specimen-incident bar interface gets an axial and a transverse velocity. Specimens endure a combined compression-shear loading at high strain rates. The compression stress and strain of the specimens are deduced from signals recorded by strain gages mounted on the bars. The shear stress is measured by two piezoelectric transducers of quartz (Y-cut with rotation angle 17.7°) embedded at the close-to-specimen end of transmission bars; the shear strain is measured with a novel optical technique, which is based on the luminous flux method. An analytic model was proposed and validated by the numerical simulations. The simulation results yield good agreement with the analytic results. The proposed technique was then validated through experiments carried out on lead specimens, by comparing experimental results with that of the split Hopkinson pressure bar experiments.

  12. Active stabilization to prevent surge in centrifugal compression systems

    NASA Technical Reports Server (NTRS)

    Epstein, Alan H.; Greitzer, Edward M.; Simon, Jon S.; Valavani, Lena

    1993-01-01

    This report documents an experimental and analytical study of the active stabilization of surge in a centrifugal engine. The aims of the research were to extend the operating range of a compressor as far as possible and to establish the theoretical framework for the active stabilization of surge from both an aerodynamic stability and a control theoretic perspective. In particular, much attention was paid to understanding the physical limitations of active stabilization and how they are influenced by control system design parameters. Previously developed linear models of actively stabilized compressors were extended to include such nonlinear phenomena as bounded actuation, bandwidth limits, and robustness criteria. This model was then used to systematically quantify the influence of sensor-actuator selection on system performance. Five different actuation schemes were considered along with four different sensors. Sensor-actuator choice was shown to have a profound effect on the performance of the stabilized compressor. The optimum choice was not unique, but rather shown to be a strong function of some of the non-dimensional parameters which characterize the compression system dynamics. Specifically, the utility of the concepts were shown to depend on the system compliance to inertia ratio ('B' parameter) and the local slope of the compressor speedline. In general, the most effective arrangements are ones in which the actuator is most closely coupled to the compressor, such as a close-coupled bleed valve inlet jet, rather than elsewhere in the flow train, such as a fuel flow modulator. The analytical model was used to explore the influence of control system bandwidth on control effectiveness. The relevant reference frequency was shown to be the compression system's Helmholtz frequency rather than the surge frequency. The analysis shows that control bandwidths of three to ten times the Helmholtz frequency are required for larger increases in the compressor flow range

  13. Active compressive intraoceanic deformation: early stages of ophiolites emplacement?

    NASA Astrophysics Data System (ADS)

    Chamot-Rooke, Nicolas; Delescluse, Matthias; Montési, Laurent

    2010-05-01

    Oceanic lithosphere is strong and continental lithosphere is weak. As a result, there is relatively little deformation in the oceanic domain away from plate boundaries. However, the interior of oceanic lithosphere does deform when highly stressed. We review here places where intraoceanic compression is at work. In the more than 30 years since the first observations of active compressive intraplate deformation in the Central Indian Ocean through seismic profiling (Eittreim et al., 1972), compressive deformation has been identified in a variety of other oceanic tectonic settings: as a result of small differential motion between large plates (between North America and South America in the Central Atlantic; between Eurasia and Nubia offshore Gibraltar; between Macquarie and Australia plates in the Southern Ocean), within back-arcs (northwest Celebes Sea, Okushiri Ridge in the Japan Sea, on the eastern border of the Caroline plate), and ahead of subduction (Zenisu Ridge off Nankai Trough). Deformation appears to be more diffuse when larger plates are involved, and more localized for younger plates, perhaps in relation with the increasing rigidity of oceanic plates with age. The best example of diffuse deformation studied so far remains the Central Indian Ocean. Numerous marine data have been collected in this area, including shallow and deep seismic, heat flow measurements, multibeam bathymetry. The present-day deformation field has been modeled using GPS and earthquakes as far field and near field constraints respectively. Reactivation of the oceanic fabric (including for portions of the Indo-Australian plate which are now in subduction as evidenced by the September 2009 Padang earthquake), selective fault abandonment (Delescluse et al., 2008) and serpentinization (Delescluse and Chamot-Rooke, 2008) are some of the important processes that shape the present-day pattern of deformation. These rare intraplate deformation areas constitute excellent natural laboratories to

  14. A low cost method of testing compression-after-impact strength of composite laminates

    NASA Technical Reports Server (NTRS)

    Nettles, Alan T.

    1991-01-01

    A method was devised to test the compression strength of composite laminate specimens that are much thinner and wider than other tests require. The specimen can be up to 7.62 cm (3 in) wide and as thin as 1.02 mm (.04 in). The best features of the Illinois Institute of Technology Research Institute (IITRI) fixture are combined with an antibuckling jig developed and used at the University of Dayton Research Institute to obtain a method of compression testing thin, wide test coupons on any 20 kip (or larger) loading frame. Up to 83 pct. less composite material is needed for the test coupons compared to the most commonly used compression-after-impact (CAI) tests, which calls for 48 ply thick (approx. 6.12 mm) test coupons. Another advantage of the new method is that composite coupons of the exact lay-up and thickness of production parts can be tested for CAI strength, thus yielding more meaningful results. This new method was used to compression test 8 and 16 ply laminates of T300/934 carbon/epoxy. These results were compared to those obtained using ASTM standard D 3410-87 (Celanese compression test). CAI testing was performed on IM6/3501-6, IM7/SP500 and IM7/F3900. The new test method and associated fixture work well and is a valuable asset to MSFC's damage tolerance program.

  15. Comparison of ring compression testing to three point bend testing for unirradiated ZIRLO cladding

    SciTech Connect

    None, None

    2015-04-01

    Safe shipment and storage of nuclear reactor discharged fuel requires an understanding of how the fuel may perform under the various conditions that can be encountered. One specific focus of concern is performance during a shipment drop accident. Tests at Savannah River National Laboratory (SRNL) are being performed to characterize the properties of fuel clad relative to a mechanical accident condition such as a container drop. Unirradiated ZIRLO tubing samples have been charged with a range of hydride levels to simulate actual fuel rod levels. Samples of the hydrogen charged tubes were exposed to a radial hydride growth treatment (RHGT) consisting of heating to 400°C, applying initial hoop stresses of 90 to 170 MPa with controlled cooling and producing hydride precipitates. Initial samples have been tested using both a) ring compression test (RCT) which is shown to be sensitive to radial hydride and b) three-point bend tests which are less sensitive to radial hydride effects. Hydrides are generated in Zirconium based fuel cladding as a result of coolant (water) oxidation of the clad, hydrogen release, and a portion of the released (nascent) hydrogen absorbed into the clad and eventually exceeding the hydrogen solubility limit. The orientation of the hydrides relative to the subsequent normal and accident strains has a significant impact on the failure susceptability. In this study the impacts of stress, temperature and hydrogen levels are evaluated in reference to the propensity for hydride reorientation from the circumferential to the radial orientation. In addition the effects of radial hydrides on the Quasi Ductile Brittle Transition Temperature (DBTT) were measured. The results suggest that a) the severity of the radial hydride impact is related to the hydrogen level-peak temperature combination (for example at a peak drying temperature of 400°C; 800 PPM hydrogen has less of an impact/ less radial hydride fraction than 200 PPM hydrogen for the same thermal

  16. Consequences of Laughter Upon Trunk Compression and Cortical Activation: Linear and Polynomial Relations.

    PubMed

    Svebak, Sven

    2016-08-01

    Results from two studies of biological consequences of laughter are reported. A proposed inhibitory brain mechanism was tested in Study 1. It aims to protect against trunk compression that can cause health hazards during vigorous laughter. Compression may be maximal during moderate durations and, for protective reasons, moderate in enduring vigorous laughs. Twenty-five university students volunteered to see a candid camera film. Laughter responses (LR) and the superimposed ha-responses were operationally assessed by mercury-filled strain gauges strapped around the trunk. On average, the thorax compression amplitudes exceeded those of the abdomen, and greater amplitudes were seen in the males than in the females after correction for resting trunk circumference. Regression analyses supported polynomial relations because medium LR durations were associated with particularly high thorax amplitudes. In Study 2, power changes were computed in the beta and alpha EEG frequency bands of the parietal cortex from before to after exposure to the comedy "Dinner for one" in 56 university students. Highly significant linear relations were calculated between the number of laughs and post-exposure cortical activation (increase of beta, decrease of alpha) due to high activation after frequent laughter. The results from Study 1 supported the hypothesis of a protective brain mechanism that is activated during long LRs to reduce the risk of harm to vital organs in the trunk cavity. The results in Study 2 supported a linear cortical activation and, thus, provided evidence for a biological correlate to the subjective experience of mental refreshment after laughter. PMID:27547260

  17. Buckling Test under Axial Compression for Multiwall Carbon Nanotubes

    NASA Astrophysics Data System (ADS)

    Nishio, Mitsumasa; Akita, Seiji; Nakayama, Yoshikazu

    2005-08-01

    We have investigated buckling phenomena under axial compression for multiwall carbon nanotubes with the same outer diameter with different wall thicknesses obtained by the extraction of inner shells. According to the Euler’s buckling model described by the continuum model, Young’s moduli of the nanotube before and after the extraction of the inner shells were evaluated to be 0.77 and 0.80 TPa, respectively. This good agreement between the two values indicates that the classical continuum model is effective for describing the mechanical behaviors of multiwall nanotubes.

  18. Two-spring model for active compression textiles with integrated NiTi coil actuators

    NASA Astrophysics Data System (ADS)

    Holschuh, B.; Newman, D.

    2015-03-01

    This paper describes the development and implementation of a two-spring model to predict the performance of hybrid compression textiles combining passive elastic fabrics and integrated NiTi shape memory alloy (SMA) coil actuators. An analytic model that treats passive fabric-SMA coil systems as conjoined linear springs is presented to predict garment passive and active counter-pressure as a function of 11 design variables. For a fixed SMA coil design (encompassing five design variables), the model predicts that passive fabric material modulus, initial length, width and thickness determine both passive counter-pressure magnitude and activation stroke length, and that passive and active pressures are highly dependent on the relative unstretched lengths of the conjoined SMA-fabric system compared to the total limb circumference. Several passive fabrics were tested to determine their moduli and to generally assess the fabric linearity model assumption: two fabrics (spandex and neoprene) were found to behave linearly up to 200% strain, while two other fabrics (flat polyester elastic and a tri-laminate Lycra) were found to be nonlinear in the same strain envelope. Five hypothetical compression tourniquet designs are presented using experimentally determined fabric characteristics and previously studied SMA actuators developed at MIT. The performance of each tourniquet design is discussed with a specific focus on mechanical counter-pressure (MCP) space suit design requirements, with designs presented that achieve the full MCP design specification (\\gt 29.6 kPa) while minimizing (\\lt 5 mm) garment thickness. The modeling framework developed in this effort enables compression garment designers to tailor counter-pressure and activation stroke properties of active compression garments based on a variety of design parameters to meet a wide range of performance specifications.

  19. Tests of Airfoils Designed to Delay the Compressibility Burble

    NASA Technical Reports Server (NTRS)

    Stack, John

    1939-01-01

    Development of airfoil sections suitable for high-speed applications has generally been difficult because little was known of the flow phenomenon that occurs at high speeds. A definite critical speed has been found at which serious detrimental flow changes occur that lead to serious losses in lift and large increases in drag. This flow phenomenon, called the compressibility burble, was originally a propeller problem, but with the development of higher speed aircraft serious consideration must be given to other parts of the airplane. Fundamental investigations of high-speed airflow phenomenon have provided new information. An important conclusion of this work has been the determination of the critical speed, that is, the speed at which the compressibility burble occurs. The critical speed was shown to be the translational velocity at which the sum of the translational velocity and the maximum local induced velocity at the surface of the airfoil or other body equals the local speed of sound. Obviously then higher critical speeds can be attained through the development of airfoils that have minimum induced velocity for any given value of the lift coefficient. Presumably, the highest critical speed will be attained by an airfoil that has uniform chordwise distribution of induced velocity or, in other words, a flat pressure distribution curve. The ideal airfoil for any given high-speed application is, then, that form which at its operating lift coefficient has uniform chordwise distribution of induced velocity. Accordingly, an analytical search for such airfoil forms has been conducted and these forms are now being investigated experimentally in the 23-inch high-speed wind tunnel. The first airfoils investigated showed marked improvement over those forms already available, not only as to critical speed buy also the drag at low speeds is decreased considerably. Because of the immediate marked improvement, it was considered desirable to extend the thickness and lift

  20. On Reducing Test Power, Volume and Routing Cost by Chain Reordering and Test Compression Techniques

    NASA Astrophysics Data System (ADS)

    Lin, Chia-Yi; Hsu, Li-Chung; Chen, Hung-Ming

    With the advancement of VLSI manufacturing technology, entire electronic systems can be implemented in a single integrated circuit. Due to the complexity in SoC design, circuit testability becomes one of the most challenging works. Without careful planning in Design For Testability (DFT) design, circuits consume more power in test mode operation than that in normal functional mode. This elevated testing power may cause problems including overall yield lost and instant circuit damage. In this paper, we present two approaches to minimize scan based DFT power dissipation. First methodology includes routing cost consideration in scan chain reordering after cell placement, while second methodology provides test pattern compression for lower power. We formulate the first problem as a Traveling Salesman Problem (TSP), with different cost evaluation from [18], [19], and apply an efficient heuristic to solve it. In the second problem, we provide a selective scan chain architecture and perform a simple yet effective encoding scheme for lower scan testing power dissipation. The experimental results of ISCAS'89 benchmarks show that the first methodology obtains up to 10% average power saving under the same low routing cost compared with a recent result in [19]. The second methodology reduces over 17% of test power compared with filling all don't care (X) bit with 0 in one of ISCAS'89 benchmarks. We also provide the integration flow of these two approaches in this paper.

  1. Analysis and testing of axial compression in imperfect slender truss struts

    NASA Technical Reports Server (NTRS)

    Lake, Mark S.; Georgiadis, Nicholas

    1990-01-01

    The axial compression of imperfect slender struts for large space structures is addressed. The load-shortening behavior of struts with initially imperfect shapes and eccentric compressive end loading is analyzed using linear beam-column theory and results are compared with geometrically nonlinear solutions to determine the applicability of linear analysis. A set of developmental aluminum clad graphite/epoxy struts sized for application to the Space Station Freedom truss are measured to determine their initial imperfection magnitude, load eccentricity, and cross sectional area and moment of inertia. Load-shortening curves are determined from axial compression tests of these specimens and are correlated with theoretical curves generated using linear analysis.

  2. Compressed-air energy storage: Pittsfield aquifer field test

    SciTech Connect

    Bui, H.V.; Herzog, R.A.; Jacewicz, D.M.; Lange, G.R.; Scarpace, E.R.; Thomas, H.H. )

    1990-02-01

    This report documents the results of a comprehensive investigation into the practical feasibility for Compressed Air Energy Storage (CAES) in Porous Media. Natural gas porous media storage technology developed from seventy years of experience by the natural gas storage industry is applied to the investigation of CAES in porous media. A major objective of this investigation is the geologic characterization, deliverability prediction, and operations analysis of the Pittsfield CAES aquifer experiment, conducted in Pike County, Illinois during 1981--85 under EPRI/DOE sponsorship. Emphasis has been placed on applying accepted petroleum engineering concepts to the study of deliverability and on the characterization and quantification of oxygen losses which reportedly occurred at Pittsfield. Other objectives are to apply the natural gas underground storage technology and approach to a general study of CAES feasibility in porous media reservoirs, with emphasis on the practical risks and constraints of air storage in aquifer and depleted natural gas reservoirs, the effects of water on CAES operation, corrosion effects, and a review of air dehydration options.

  3. Compression-ignition engine tests of several fuels

    NASA Technical Reports Server (NTRS)

    Spanogle, J A

    1932-01-01

    The tests reported in this paper were made to devise simple engine tests which would rate fuels as to their comparative value and their suitability for the operating conditions of the individual engine on which the tests are made. Three commercial fuels were used in two test engines having combustion chambers with and without effective air flow. Strictly comparative performance tests gave almost identical results for the three fuels. Analysis of indicator cards allowed a differentiation between fuels on a basis of rates of combustion. The same comparative ratings were obtained by determining the consistent operating range of injection advance angle for the three fuels. The difference in fuels is more pronounced in a quiescent combustion chamber than in one with high-velocity air flow. A fuel is considered suitable for the operating conditions of an engine with a quiescent combustion chamber if it permits the injection of the fuel to be advanced beyond the optimum without exceeding allowable knock or allowable maximum cylinder pressures.

  4. Towards the development of active compression bandages using dielectric elastomer actuators

    NASA Astrophysics Data System (ADS)

    Pourazadi, S.; Ahmadi, S.; Menon, C.

    2014-06-01

    Disorders associated with the lower extremity venous system are common and significantly affect the quality of life of a large number of individuals. These disorders include orthostatic hypotension, oedema, deep vein thrombosis and a number of other conditions related to insufficient venous blood return. The common recommended treatment for these disorders is the use of hosiery compression stockings. In this research, an active compression bandage (ACB) based on the technology of dielectric elastomeric actuators (DEA) was designed, prototyped and tested. A customized calf prototype (CP) was developed to measure the pressure applied by the ACB. Experimental results performed with the CP showed that the pressure applied by the ACB could be electrically controlled to be either below or above the pressure exerted by commercially available compression stockings. An analytical model was used to provide the design criteria. A finite element model (FEM) was also developed to simulate the electromechanical behaviour of the DEA. Comparison of the experimental results with the FEM and analytical models showed that the modelling could accurately predict the behaviour of the ACB. The FEM was subsequently used to study how to improve the ACB performance by varying geometrical parameters such as the ACB thickness.

  5. Consequences of Laughter Upon Trunk Compression and Cortical Activation: Linear and Polynomial Relations

    PubMed Central

    Svebak, Sven

    2016-01-01

    Results from two studies of biological consequences of laughter are reported. A proposed inhibitory brain mechanism was tested in Study 1. It aims to protect against trunk compression that can cause health hazards during vigorous laughter. Compression may be maximal during moderate durations and, for protective reasons, moderate in enduring vigorous laughs. Twenty-five university students volunteered to see a candid camera film. Laughter responses (LR) and the superimposed ha-responses were operationally assessed by mercury-filled strain gauges strapped around the trunk. On average, the thorax compression amplitudes exceeded those of the abdomen, and greater amplitudes were seen in the males than in the females after correction for resting trunk circumference. Regression analyses supported polynomial relations because medium LR durations were associated with particularly high thorax amplitudes. In Study 2, power changes were computed in the beta and alpha EEG frequency bands of the parietal cortex from before to after exposure to the comedy “Dinner for one” in 56 university students. Highly significant linear relations were calculated between the number of laughs and post-exposure cortical activation (increase of beta, decrease of alpha) due to high activation after frequent laughter. The results from Study 1 supported the hypothesis of a protective brain mechanism that is activated during long LRs to reduce the risk of harm to vital organs in the trunk cavity. The results in Study 2 supported a linear cortical activation and, thus, provided evidence for a biological correlate to the subjective experience of mental refreshment after laughter. PMID:27547260

  6. Sweep and Compressibility Effects on Active Separation Control at High Reynolds Numbers

    NASA Technical Reports Server (NTRS)

    Seifert, Avi; Pack, LaTunia G.

    2000-01-01

    This paper explores the effects of compressibility, sweep and excitation location on active separation control at high Reynolds numbers. The model, which was tested in a cryogenic pressurized wind tunnel, simulates the upper surface of a 20% thick Glauert Goldschmied type airfoil at zero angle of attack. The flow is fully turbulent since the tunnel sidewall boundary layer flows over the model. Without control, the flow separates at the highly convex area and a large turbulent separation bubble is formed. Periodic excitation is applied to gradually eliminate the separation bubble. Two alternative blowing slot locations as well as the effect of compressibility, sweep and steady suction or blowing were studied. During the test the Reynolds numbers ranged from 2 to 40 million and Mach numbers ranged from 0.2 to 0.7. Sweep angles were 0 and 30 deg. It was found that excitation must be introduced slightly upstream of the separation region regardless of the sweep angle at low Mach number. Introduction of excitation upstream of the shock wave is more effective than at its foot. Compressibility reduces the ability of steady mass transfer and periodic excitation to control the separation bubble but excitation has an effect on the integral parameters, which is similar to that observed in low Mach numbers. The conventional swept flow scaling is valid for fully and even partially attached flow, but different scaling is required for the separated 3D flow. The effectiveness of the active control is not reduced by sweep. Detailed flow field dynamics are described in the accompanying paper.

  7. Analysis of three-point-bend test for materials with unequal tension and compression properties

    NASA Technical Reports Server (NTRS)

    Chamis, C. C.

    1974-01-01

    An analysis capability is described for the three-point-bend test applicable to materials of linear but unequal tensile and compressive stress-strain relations. The capability consists of numerous equations of simple form and their graphical representation. Procedures are described to examine the local stress concentrations and failure modes initiation. Examples are given to illustrate the usefulness and ease of application of the capability. Comparisons are made with materials which have equal tensile and compressive properties. The results indicate possible underestimates for flexural modulus or strength ranging from 25 to 50 percent greater than values predicted when accounting for unequal properties. The capability can also be used to reduce test data from three-point-bending tests, extract material properties useful in design from these test data, select test specimen dimensions, and size structural members.

  8. Determining Tension-Compression Nonlinear Mechanical Properties of Articular Cartilage from Indentation Testing.

    PubMed

    Chen, Xingyu; Zhou, Yilu; Wang, Liyun; Santare, Michael H; Wan, Leo Q; Lu, X Lucas

    2016-04-01

    The indentation test is widely used to determine the in situ biomechanical properties of articular cartilage. The mechanical parameters estimated from the test depend on the constitutive model adopted to analyze the data. Similar to most connective tissues, the solid matrix of cartilage displays different mechanical properties under tension and compression, termed tension-compression nonlinearity (TCN). In this study, cartilage was modeled as a porous elastic material with either a conewise linear elastic matrix with cubic symmetry or a solid matrix reinforced by a continuous fiber distribution. Both models are commonly used to describe the TCN of cartilage. The roles of each mechanical property in determining the indentation response of cartilage were identified by finite element simulation. Under constant loading, the equilibrium deformation of cartilage is mainly dependent on the compressive modulus, while the initial transient creep behavior is largely regulated by the tensile stiffness. More importantly, altering the permeability does not change the shape of the indentation creep curves, but introduces a parallel shift along the horizontal direction on a logarithmic time scale. Based on these findings, a highly efficient curve-fitting algorithm was designed, which can uniquely determine the three major mechanical properties of cartilage (compressive modulus, tensile modulus, and permeability) from a single indentation test. The new technique was tested on adult bovine knee cartilage and compared with results from the classic biphasic linear elastic curve-fitting program. PMID:26240062

  9. On the compressibility effect in test particle acceleration by magnetohydrodynamic turbulence

    NASA Astrophysics Data System (ADS)

    González, C. A.; Dmitruk, P.; Mininni, P. D.; Matthaeus, W. H.

    2016-08-01

    The effect of compressibility in a charged particle energization by magnetohydrodynamic (MHD) fields is studied in the context of test particle simulations. This problem is relevant to the solar wind and the solar corona due to the compressible nature of the flow in those astrophysical scenarios. We consider turbulent electromagnetic fields obtained from direct numerical simulations of the MHD equations with a strong background magnetic field. In order to explore the flow compressibility effect over the particle dynamics, we performed different numerical experiments: an incompressible case and two weak compressible cases with Mach number M = 0.1 and M = 0.25. We analyze the behavior of protons and electrons in those turbulent fields, which are well known to form aligned current sheets in the direction of the guide magnetic field. What we call protons and electrons are test particles with scales comparable to (for protons) and much smaller than (for electrons) the dissipative scale of MHD turbulence, maintaining the correct mass ratio m e / m i . For these test particles, we show that compressibility enhances the efficiency of proton acceleration, and that the energization is caused by perpendicular electric fields generated between currents sheets. On the other hand, electrons remain magnetized and display an almost adiabatic motion, with no effect of compressibility observed. Another set of numerical experiments takes into account two fluid modifications, namely, electric field due to Hall effect and electron pressure gradient. We show that the electron pressure has an important contribution to electron acceleration allowing highly parallel energization. In contrast, no significant effect of these additional terms is observed for the protons.

  10. Tensile and compression testing of single-crystal gamma Ti-55.5Al

    SciTech Connect

    Zupan, M.; LaVan, D.; Hemker, K.J.

    1997-12-31

    Gamma based titanium aluminides are considered to be promising high temperature application alloys because of their exceptional high temperature mechanical properties and good oxidation resistance. Moreover, with a density less than half of current nickel based super alloys, the increased power to weight ratio that can be realized by using titanium aluminides is very attractive to the automotive and aircraft industries. Here the orientation and temperature dependence of the flow strength of {gamma}-TiAl is being measured to promote a fundamental understanding of the deformation mechanisms that are active in this alloy. High quality single crystals of {gamma}-Ti-55.5 Al have been grown using an optical float zone furnace, which allows for crystal seeding and provides a containerless growth environment. These crystals have been oriented using back reflection Laue and TEM and cut into microsample tensile specimens by electric discharge machining. The microsample testing technique developed at Johns Hopkins is being utilized to measure the orientation, temperature and tension/compression dependence of the flow strength of TiAl. An outline of the microsample testing techniques that have been developed for this study and preliminary results follow in this paper.

  11. Pilot Field Test: Use of a Compression Garment During a Stand Test After Long-Duration Space Flight

    NASA Technical Reports Server (NTRS)

    Laurie, S. S.; Stenger, M. B.; Phillips, T. R.; Lee, S. M. C.; Cerisano, J.; Kofman, I.; Reschke, M.

    2016-01-01

    Orthostatic intolerance (OI) is a concern for astronauts returning from long-duration space flight. One countermeasure that has been used to protect against OI after short-duration bed rest and space flight is the use of lower body and abdominal compression garments. However, since the end of the Space Shuttle era we have not been able to test crewmembers during the first 24 hours after landing on Earth. NASA's Pilot Field Test provided us the opportunity to test cardiovascular responses of crewmembers wearing the Russian Kentavr compression garment during a stand test at multiple time points throughout the first 24 hours after landing. HYPOTHESIS We hypothesized that the Kentavr compression garment would prevent an increase in heart rate (HR) >15 bpm during a 3.5-min stand test. METHODS: The Pilot Field Test was conducted up to 3 times during the first 24 hours after crewmembers returned to Earth: (1) either in a tent adjacent to the Soyuz landing site in Kazakhstan (approx.1 hr) or after transportation to the Karaganda airport (approx. 4 hr); (2) during a refueling stop in Scotland (approx.12 hr); and (3) upon return to NASA Johnson Space Center (JSC) (approx.24 hr). We measured HR and arterial pressure (finger photoplethysmography) for 2 min while the crewmember was prone and throughout 3.5 min of quiet standing. Eleven crewmembers consented to participate; however, 2 felt too ill to start the test and 1 stopped 30 sec into the stand portion of the test. Of the remaining 8 crewmembers, 2 did not wear the Russian Kentavr compression garment. Because of inclement weather at the landing site, 5 crewmembers were flown by helicopter to the Karaganda airport before initial testing and received intravenous saline before completing the stand test. One of these crewmembers wore only the portion of the Russian Kentavr compression garment that covered the lower leg and thus lacked thigh and abdominal compression. All crewmembers continued wearing the Russian Kentavr

  12. Active high-power RF switch and pulse compression system

    DOEpatents

    Tantawi, Sami G.; Ruth, Ronald D.; Zolotorev, Max

    1998-01-01

    A high-power RF switching device employs a semiconductor wafer positioned in the third port of a three-port RF device. A controllable source of directed energy, such as a suitable laser or electron beam, is aimed at the semiconductor material. When the source is turned on, the energy incident on the wafer induces an electron-hole plasma layer on the wafer, changing the wafer's dielectric constant, turning the third port into a termination for incident RF signals, and. causing all incident RF signals to be reflected from the surface of the wafer. The propagation constant of RF signals through port 3, therefore, can be changed by controlling the beam. By making the RF coupling to the third port as small as necessary, one can reduce the peak electric field on the unexcited silicon surface for any level of input power from port 1, thereby reducing risk of damaging the wafer by RF with high peak power. The switch is useful to the construction of an improved pulse compression system to boost the peak power of microwave tubes driving linear accelerators. In this application, the high-power RF switch is placed at the coupling iris between the charging waveguide and the resonant storage line of a pulse compression system. This optically controlled high power RF pulse compression system can handle hundreds of Megawatts of power at X-band.

  13. Influence of Friction and Plastic Anisotropy in Cube- and Ring-Compression Test

    NASA Astrophysics Data System (ADS)

    Terano, Motoki; Kitamura, Kazuhiko; Fukatsu, Takaaki; Mizuno, Takaji

    An extruded or rolled material such as a bar and a tube naturally possesses plastic anisotropy like a sheet. The property influences the metal flow in bulk forming as well as in sheet metal forming. In this paper, some examples of the anisotropic bulk deformations in a cube- and a ring-compression test were demonstrated. The cube with the edges of 1 mm long, which was cut out of a round bar or a tube, was compressed in z-axis under a well-lubricated condition by applying beef-tallow. After the compression test, the strain ratios of ɛy to ɛx were 0.83 and 0.76 for A1050 and A6063 respectively. They showed normal anisotropy, because the ratios of ɛy/ɛx keep unity if they are isotropic materials. Furthermore, friction also affects the metal flow for the anisotropic material. The ratios of ɛy/ɛx changed when the cubes were compressed under different frictional conditions by using some lubricants such as beef-tallow, VG460, VG100, castor oil, and no lubrication. The anisotropic deformation was restrained by the higher-frictional die-surface. Also the ring-compression test, as another example, was investigated, which is a well-established test to determine the friction coefficients by measuring the change in the inner diameter. Plastic anisotropy and friction influenced the reduction in the inner diameter, so the coefficient of friction must be decided with appropriate diagrams that consider the plastic anisotropy of the material.

  14. Vapor Compression Distillation Urine Processor Lessons Learned from Development and Life Testing

    NASA Technical Reports Server (NTRS)

    Hutchens, Cindy F.; Long, David A.

    1999-01-01

    Vapor Compression Distillation (VCD) is the chosen technology for urine processing aboard the International Space Station (155). Development and life testing over the past several years have brought to the forefront problems and solutions for the VCD technology. Testing between 1992 and 1998 has been instrumental in developing estimates of hardware life and reliability. It has also helped improve the hardware design in ways that either correct existing problems or enhance the existing design of the hardware. The testing has increased the confidence in the VCD technology and reduced technical and programmatic risks. This paper summarizes the test results and changes that have been made to the VCD design.

  15. Test of superplastically formed corrugated aluminum compression specimens with beaded webs

    NASA Technical Reports Server (NTRS)

    Davis, Randall C.; Royster, Dick M.; Bales, Thomas T.; James, William F.; Shinn, Joseph M., Jr.

    1991-01-01

    Corrugated wall sections provide a highly efficient structure for carrying compressive loads in aircraft and spacecraft fuselages. The superplastic forming (SPF) process offers a means to produce complex shells and panels with corrugated wall shapes. A study was made to investigate the feasibility of superplastically forming 7475-T6 aluminum sheet into a corrugated wall configuration and to demonstrate the structural integrity of the construction by testing. The corrugated configuration selected has beaded web segments separating curved-cap segments. Eight test specimens were fabricated. Two specimens were simply a single sheet of aluminum superplastically formed to a beaded-web, curved-cap corrugation configuration. Six specimens were single-sheet corrugations modified by adhesive bonding additional sheet material to selectively reinforce the curved-cap portion of the corrugation. The specimens were tested to failure by crippling in end compression at room temperature.

  16. Identifying and Characterizing Discrepancies Between Test and Analysis Results of Compression-Loaded Panels

    NASA Technical Reports Server (NTRS)

    Thornburgh, Robert P.; Hilburger, Mark W.

    2005-01-01

    Results from a study to identify and characterize discrepancies between validation tests and high-fidelity analyses of compression-loaded panels are presented. First, potential sources of the discrepancies in both the experimental method and corresponding high-fidelity analysis models were identified. Then, a series of laboratory tests and numerical simulations were conducted to quantify the discrepancies and develop test and analysis methods to account for the discrepancies. The results indicate that the discrepancies between the validation tests and high-fidelity analyses can be attributed to imperfections in the test fixture and specimen geometry; test-fixture-induced changes in specimen geometry; and test-fixture-induced friction on the loaded edges of the test specimen. The results also show that accurate predictions of the panel response can be obtained when these specimen imperfections and edge conditions are accounted for in the analysis. The errors in the tests and analyses, and the methods used to characterize these errors are presented.

  17. Rapid-Rate Compression Testing of Sheet Materials at High Temperatures

    NASA Technical Reports Server (NTRS)

    Bernett, E. C.; Gerberich, W. W.

    1961-01-01

    This Report describes the test equipment that was developed and the procedures that were used to evaluate structural sheet-material compression properties at preselected constant strain rates and/or loads. Electrical self-resistance was used to achieve a rapid heating rate of 200 F/sec. Four materials were tested at maximum temperatures which ranged from 600 F for the aluminum alloy to 2000 F for the Ni-Cr-Co iron-base alloy. Tests at 0.1, 0.001, and 0.00001 in./in./sec showed that strain rate has a major effect on the measured strength, especially at the high temperatures. The tests, under conditions of constant temperature and constant compression stress, showed that creep deformation can be a critical factor even when the time involved is on the order of a few seconds or less. The theoretical and practical aspects of rapid-rate compression testing are presented, and suggestions are made regarding possible modifications of the equipment which would improve the over-all capabilities.

  18. Hot Deformation Behavior of NiTiHf Shape Memory Alloy Under Hot Compression Test

    NASA Astrophysics Data System (ADS)

    Belbasi, Majid; Salehi, Mohammad T.; Mousavi, Seyed Ali Asghar Akbari

    2012-12-01

    In this study, the hot deformation behavior of Ni49Ti36Hf15 alloy was investigated. Compression tests were carried out at temperatures ranging from 800 to 1100 °C and at the strain rates of 0.001-1/s. The peak stress decreases with increasing deformation temperature and decreasing strain rate, a behavior which can be described by plotting the Zener-Hollomon parameter as a function of stress. It was realized that dynamic recrystallization (DRX) was responsible for flow softening. Most of the samples exhibited typical DRX stress-strain curves with a single peak stress followed by a gradual fall down stress. Microstructure evolution showed that new recrystallized grains formed in the vicinity of grain boundaries. The hyperbolic-sine-type constitutive model of Ni49Ti36Hf15 alloy was obtained to provide basic data for determining reasonable hot-forming process. The activation energy for hot deformation of the Ni49Ti36Hf15 alloy was close to 410 kJ/mol.

  19. Infarcted rat myocardium: Data from biaxial tensile and uniaxial compressive testing and analysis of collagen fibre orientation.

    PubMed

    Sirry, Mazin S; Butler, J Ryan; Patnaik, Sourav S; Brazile, Bryn; Bertucci, Robbin; Claude, Andrew; McLaughlin, Ron; Davies, Neil H; Liao, Jun; Franz, Thomas

    2016-09-01

    Myocardial infarction was experimentally induced in rat hearts and harvested immediately, 7, 14 and 28 days after the infarction induction. Anterior wall infarct samples underwent biaxial tensile and uniaxial compressive testing. Orientation of collagen fibres was analysed following mechanical testing. In this paper, we present the tensile and compressive stress-strain raw data, the calculated tensile and compressive moduli and the measured angles of collagen orientation. The presented data is associated with the research article titled "Characterisation of the mechanical properties of infarcted myocardium in the rat under biaxial tension and uniaxial compression" (Sirry et al., 2016) [1]. PMID:27579338

  20. TESTING TESTS ON ACTIVE GALACTIC NUCLEI MICROVARIABILITY

    SciTech Connect

    De Diego, Jose A.

    2010-03-15

    Literature on optical and infrared microvariability in active galactic nuclei (AGNs) reflects a diversity of statistical tests and strategies to detect tiny variations in the light curves of these sources. Comparison between the results obtained using different methodologies is difficult, and the pros and cons of each statistical method are often badly understood or even ignored. Even worse, improperly tested methodologies are becoming more and more common, and biased results may be misleading with regard to the origin of the AGN microvariability. This paper intends to point future research on AGN microvariability toward the use of powerful and well-tested statistical methodologies, providing a reference for choosing the best strategy to obtain unbiased results. Light curves monitoring has been simulated for quasars and for reference and comparison stars. Changes for the quasar light curves include both Gaussian fluctuations and linear variations. Simulated light curves have been analyzed using {chi}{sup 2} tests, F tests for variances, one-way analyses of variance and C-statistics. Statistical Type I and Type II errors, which indicate the robustness and the power of the tests, have been obtained in each case. One-way analyses of variance and {chi}{sup 2} prove to be powerful and robust estimators for microvariations, while the C-statistic is not a reliable methodology and its use should be avoided.

  1. Frictionless compression testing using load-applying platens made from porous graphite aerostatic bearings

    NASA Astrophysics Data System (ADS)

    El-Aguizy, Tarek; Plante, Jean-Sebastien; Slocum, Alexander H.; Vogan, John D.

    2005-07-01

    In compression testing of soft materials at high strains, friction between a sample and the load-applying platens induces a differential lateral expansion that is visually evident as barreling. Barreling reduces the accuracy of the tests as a means of establishing accurate material properties. Current techniques for reducing friction, which involve liquid squeeze film lubrication, may not achieve true frictionless interfaces, are messy, and may adversely affect some samples. This article examines the use of porous graphite aerostatic bearings as a frictionless testing interface. The physics of a soft material under compressive loading by porous air bearings is investigated with simple finite element analysis and air flow models. An aerostatic bearing assembly is also constructed and compared to other friction reduction techniques. The results of these experiments indicate that there are benefits to using air bearings as they are clean, chemically inert, extremely stiff, reduce friction to levels comparable to existing methods, have negligible squeeze film effect, are repeatable, and allow for cyclic compression testing.

  2. Experimental Results From Stitched Composite Multi-Bay Fuselage Panels Tested Under Uni-Axial Compression

    NASA Technical Reports Server (NTRS)

    Baker, Donald J.

    2004-01-01

    The experimental results from two stitched VARTM composite panels tested under uni-axial compression loading are presented. The curved panels are divided by frames and stringers into five or six bays with a column of three bays along the compressive loading direction. The frames are supported at the ends to resist out-of-plane translation. Back-to-back strain gages are used to record the strain and displacement transducers were used to record the out-of-plane displacements. In addition a full-field measurement technique that utilizes a camera-based-stero-vision system was used to record displacements. The panels were loaded in increments to determine the first bay to buckle. Loading was discontinued at limit load and the panels were removed from the test machine for impact testing. After impacting at 20 ft-lbs to 25 ft-lbs of energy with a spherical indenter, the panels were loaded in compression until failure. Impact testing reduced the axial stiffness 4 percent and less than 1 percent. Postbuckled axial panel stiffness was 52 percent and 70 percent of the pre-buckled stiffness.

  3. Acoustic Emission and Ultrasonic Characterization of Jurassic Navajo Formation Deformation During Axisymmetric Compression Testing

    NASA Astrophysics Data System (ADS)

    Rinehart, A. J.; Dewers, T. A.; Holcomb, D. J.; Broome, S. T.

    2011-12-01

    Linking continuum-scale and microscale brittle damage in rock remains a challenge impacting CO2 sequestration, secondary recovery, structural monitoring, and other geotechnical engineering applications. We examine if the mode of micromechanical failure scales directly up to continuum-scale damage-induced velocity anisotropy. Axisymmetric drained lab-dry compression experiments are performed on facies of moderately cemented finely laminated quartz arenite from the Jurassic Navajo Formation, a target reservoir rock for CO2 sequestration in Utah. The tests are 1 unconfined uniaxial compression test, 1 hydrostatic compression test, and 3 triaxial compression tests. Microscale damage is monitored using acoustic emissions (AE) and continuum scale damage is monitored with ultrasonic velocity scans. During the non-hydrostatic tests, three to five unload loops are performed pre-failure, with one unload loop performed post-failure. While stresses are increasing, AEs are monitored continuously using 1.6-mm diameter, 0.5-mm thick PZT-5A pins attached circumferentially around the cylindrical sample, and with 6-mm diameter, 2-mm thick PZT-5A discs at the ends of the sample. Before and after each unload loop, the test is paused and the AE transducers sequentially emit an ultrasonic pulse to measure wave speeds. The resulting elastic wave is detected by the other AE transducers. Post-test, the changing anisotropic velocity structure of the rock during compression and failure is compared to the locations, frequency, and relative moment tensors of the AEs measured between ultrasonic scans. Pre- and post-test visual and x-ray CT scan observations of the sample are compared to the acoustic metrics. These tiered observations of rock damage will further elucidate the scaling of microscale brittle failure to the continuum-scale This work was supported as part of the Center for Frontiers of Subsurface Energy Security, an Energy Frontier Research Center funded by the U.S. Department of

  4. Tensile, Compression, Open-Hole Compression and Double Cantilever Beam Fracture Toughness Testing of Multiple NASA Langley Research Center Composite Materials

    NASA Technical Reports Server (NTRS)

    Adams, Donald F.

    1999-01-01

    The attached data summarizes the work performed by the Composite Materials Research Group at the University of Wyoming funded by the NASA LaRC Research Grant NAG-1-1294. The work consisted primarily of tension, compression, open-hole compression and double cantilever beam fracture toughness testing performed an a variety of NASA LaRC composite materials. Tests were performed at various environmental conditions and pre-conditioning requirements. The primary purpose of this work was to support the LaRC material development efforts. The data summaries are arranged in chronological order from oldest to newest.

  5. Neurilemmoma of Deep Peroneal Nerve Sensory Branch : Thermographic Findings with Compression Test.

    PubMed

    Ryu, Seung Jun; Zhang, Ho Yeol

    2015-09-01

    We report a case of neurilemmoma of deep peroneal nerve sensory branch that triggered sensory change with compression test on lower extremity. After resection of tumor, there are evoked thermal changes on pre- and post-operative infrared (IR) thermographic images. A 52-year-old female presented with low back pain, sciatica, and sensory change on the dorsal side of the right foot and big toe that has lasted for 9 months. She also presented with right tibial mass sized 1.2 cm by 1.4 cm. Ultrasonographic imaging revealed a peripheral nerve sheath tumor arising from the peroneal nerve. IR thermographic image showed hyperthermia when the neurilemoma induced sensory change with compression test on the fibular area, dorsum of foot, and big toe. After surgery, the symptoms and thermographic changes were relieved and disappeared. The clinical, surgical, radiographic, and thermographic perspectives regarding this case are discussed. PMID:26539275

  6. Neurilemmoma of Deep Peroneal Nerve Sensory Branch : Thermographic Findings with Compression Test

    PubMed Central

    Ryu, Seung Jun

    2015-01-01

    We report a case of neurilemmoma of deep peroneal nerve sensory branch that triggered sensory change with compression test on lower extremity. After resection of tumor, there are evoked thermal changes on pre- and post-operative infrared (IR) thermographic images. A 52-year-old female presented with low back pain, sciatica, and sensory change on the dorsal side of the right foot and big toe that has lasted for 9 months. She also presented with right tibial mass sized 1.2 cm by 1.4 cm. Ultrasonographic imaging revealed a peripheral nerve sheath tumor arising from the peroneal nerve. IR thermographic image showed hyperthermia when the neurilemoma induced sensory change with compression test on the fibular area, dorsum of foot, and big toe. After surgery, the symptoms and thermographic changes were relieved and disappeared. The clinical, surgical, radiographic, and thermographic perspectives regarding this case are discussed. PMID:26539275

  7. PDM performance Test Results and Preliminary Analysis: Incompressible and Compressible Fluids

    SciTech Connect

    Dreesen, D.S.; Gruenhagan, E.; Cohen, J.C.; Moran, D.W.

    1999-02-01

    Three, small diameter, Moineau, positive displacement (drilling) motors (PDMs) were dynamometer tested using water, air-water mist, air-water foam, and aerated water. The motors included (1) a 1.5-inch OD, single-lobe mud motor; (2) a 1.69-inch OD, 5:6 multi-lobe mud motor; and (3) a 1.75-inch OD, 5:6 multi-lobe air motor. This paper describes the test apparatus, procedures, data analysis, and results. Incompressible and compressible fluid performance are compared; linear performance, predicted by a positive displacement motor model, is identified where it occurs. Preliminary results and conclusions are (1) the performance of all three motors is accurately modeled using a two-variable, linear model for incompressible fluid and (2) the model was not successfully adapted to model compressible fluid performance.

  8. Evaluation of press-and-sinter parameters for tantalum pentoxide by the diametral compression test

    SciTech Connect

    Livne, Z.; Fields, R.J.; Agulyansky, A.

    1997-05-15

    Submicron Ta{sub 2}O{sub 5} powder was consolidated by cold pressing using pressures between 24 MPa and 240 MPa followed by sintering at temperatures in the range 1300 degrees C to 1500 degrees C. The resulting disks were fractured in diametral compression tests (DCT) to determine the tensile strength. The strength, mode of fracture, and fracture surface were subsequently used to identify potential processing routes for high density, fine grained Ta{sub 2}O{sub 5} for the use as sputtering targets. Besides the conventional single or triple cleft fracture, two other modes of failure were observed in the diametrical compression test: delamination due to stratification flaws introduced by high pressure pre-pressing before sintering, and fragmentation caused by slow microcrack growth in the presence of phase transformation stresses arising in samples sintered above the transformation temperature of 1360 degrees C.

  9. Design and Testing of CO2 Compression Using Supersonic Shockware Technology

    SciTech Connect

    Joe Williams; Michael Aarnio; Kirk Lupkes; Sabri Deniz

    2010-08-31

    Documentation of work performed by Ramgen and subcontractors in pursuit of design and construction of a 10 MW supersonic CO{sub 2} compressor and supporting facility. The compressor will demonstrate application of Ramgen's supersonic compression technology at an industrial scale using CO{sub 2} in a closed-loop. The report includes details of early feasibility studies, CFD validation and comparison to experimental data, static test experimental results, compressor and facility design and analyses, and development of aero tools.

  10. Index of Unconfined Compressive Strength of SAFOD Core by Means of Point-Load Penetrometer Tests

    NASA Astrophysics Data System (ADS)

    Enderlin, M. B.; Weymer, B.; D'Onfro, P. S.; Ramos, R.; Morgan, K.

    2010-12-01

    The San Andreas Fault Observatory at Depth (SAFOD) project is motivated by the need to answer fundamental questions on the physical and chemical processes controlling faulting and earthquake generation within major plate-boundaries. In 2007, approximately 135 ft (41.1 m) of 4 inch (10.61 cm) diameter rock cores was recovered from two actively deforming traces of the San Andreas Fault. 97 evenly (more or less) distributed index tests for Unconfined Compressive Strength (UCS) where performed on the cores using a modified point-load penetrometer. The point-load penetrometer used was a handheld micro-conical point indenter referred to as the Dimpler, in reference to the small conical depression that it creates. The core surface was first covered with compliant tape that is about a square inch in size. The conical tip of the indenter is coated with a (red) dye and then forced, at a constant axial load, through the tape and into the sample creating a conical red depression (dimple) on the tape. The combination of red dye and tape preserves a record of the dimple geometrical attributes. The geometrical attributes (e.g. diameter and depth) depend on the rock UCS. The diameter of a dimple is measured with a surface measuring magnifier. Correlation between dimple diameter and UCS has been previously established with triaxial testing. The SAFOD core gave Dimpler UCS values in the range of 10 psi (68.9 KPa) to 15,000 psi (103.4 MPa). The UCS index also allows correlations between geomechanical properties and well log-derived petrophysical properties.

  11. Large-strain quasi-static compression materials tests in support of penetration modeling research

    SciTech Connect

    Brandon, S.L.; Totten, J.J.

    1990-09-01

    Target penetration by projectiles typically generates large strains, at least locally. Hence, accurate analytic modeling of penetration demands that constitutive models be calibrated using large strain material test data. Tensile test data is limited by specimen necking (the Considere criterion), restricting attainable strains. Linear extrapolation of tensile data to target strains can seriously overestimate the material flow stress, resulting in erroneously stiff analytical predictions. That is, other tests which can attain larger strains often reveal a continually decreasing tangent modulus at large strains. We report quasistatic room temperature compression tests approaching true strains of {var epsilon} = {minus}1. A few tensile tests are included to illustrate the previous point. Materials tested are 7075-T651, 5083-H131, and 6061-T651 aluminum alloys, 4340 steel and X21-C tungsten alloy. 7 refs., 6 figs.

  12. Abdominal and lower-extremity compression decreases symptoms of postural tachycardia syndrome in youth during tilt table testing.

    PubMed

    Heyer, Geoffrey L

    2014-08-01

    Little is known about the effectiveness of abdominal and lower-extremity compression in treating postural tachycardia syndrome, particularly in younger patients. This repeated-measures study of 20 young patients with postural tachycardia syndrome demonstrates that compression during head-upright tilt table testing decreases tachycardia (P<.001) and effectively attenuates orthostatic symptoms. PMID:24840763

  13. Vapor Compression Distillation Subsystem (VCDS) component enhancement, testing and expert fault diagnostics development, volume 1

    NASA Technical Reports Server (NTRS)

    Kovach, L. S.; Zdankiewicz, E. M.

    1987-01-01

    Vapor compression distillation technology for phase change recovery of potable water from wastewater has evolved as a technically mature approach for use aboard the Space Station. A program to parametrically test an advanced preprototype Vapor Compression Distillation Subsystem (VCDS) was completed during 1985 and 1986. In parallel with parametric testing, a hardware improvement program was initiated to test the feasibility of incorporating several key improvements into the advanced preprototype VCDS following initial parametric tests. Specific areas of improvement included long-life, self-lubricated bearings, a lightweight, highly-efficient compressor, and a long-life magnetic drive. With the exception of the self-lubricated bearings, these improvements are incorporated. The advanced preprototype VCDS was designed to reclaim 95 percent of the available wastewater at a nominal water recovery rate of 1.36 kg/h achieved at a solids concentration of 2.3 percent and 308 K condenser temperature. While this performance was maintained for the initial testing, a 300 percent improvement in water production rate with a corresponding lower specific energy was achieved following incorporation of the improvements. Testing involved the characterization of key VCDS performance factors as a function of recycle loop solids concentration, distillation unit temperature and fluids pump speed. The objective of this effort was to expand the VCDS data base to enable defining optimum performance characteristics for flight hardware development.

  14. Design Concepts of Polycarbonate-Based Intervertebral Lumbar Cages: Finite Element Analysis and Compression Testing

    PubMed Central

    Figueroa-Cavazos, J. Obedt; Flores-Villalba, Eduardo; Diaz-Elizondo, José A.

    2016-01-01

    This work explores the viability of 3D printed intervertebral lumbar cages based on biocompatible polycarbonate (PC-ISO® material). Several design concepts are proposed for the generation of patient-specific intervertebral lumbar cages. The 3D printed material achieved compressive yield strength of 55 MPa under a specific combination of manufacturing parameters. The literature recommends a reference load of 4,000 N for design of intervertebral lumbar cages. Under compression testing conditions, the proposed design concepts withstand between 7,500 and 10,000 N of load before showing yielding. Although some stress concentration regions were found during analysis, the overall viability of the proposed design concepts was validated. PMID:27578960

  15. Design Concepts of Polycarbonate-Based Intervertebral Lumbar Cages: Finite Element Analysis and Compression Testing.

    PubMed

    Figueroa-Cavazos, J Obedt; Flores-Villalba, Eduardo; Diaz-Elizondo, José A; Martínez-Romero, Oscar; Rodríguez, Ciro A; Siller, Héctor R

    2016-01-01

    This work explores the viability of 3D printed intervertebral lumbar cages based on biocompatible polycarbonate (PC-ISO® material). Several design concepts are proposed for the generation of patient-specific intervertebral lumbar cages. The 3D printed material achieved compressive yield strength of 55 MPa under a specific combination of manufacturing parameters. The literature recommends a reference load of 4,000 N for design of intervertebral lumbar cages. Under compression testing conditions, the proposed design concepts withstand between 7,500 and 10,000 N of load before showing yielding. Although some stress concentration regions were found during analysis, the overall viability of the proposed design concepts was validated. PMID:27578960

  16. Phase Transformations and Crack Initiation in a High-Chromium Cast Steel Under Hot Compression Tests

    NASA Astrophysics Data System (ADS)

    Tchuindjang, Jérôme Tchoufang; Torres, Ingrid Neira; Flores, Paulo; Habraken, Anne Marie; Lecomte-Beckers, Jacqueline

    2015-05-01

    The mechanical behavior of the fully austenitic matrix of high-chromium cast steel (HCCS) alloy is determined by external compression stress applied at 300 and 700 °C. The microstructure is roughly characterized toward both optical and scanning electron microscopy analyses. Dilatometry is used during heating from room temperature up to austenitization to study the solid-state phase transformations, precipitation, and dissolution reactions. Two various strengthening phenomena (precipitation hardening and stress-induced bainite transformation) and one softening mechanism (dynamic recovery) are highlighted from compression tests. The influence of the temperature and the carbide type on the mechanical behavior of the HCCS material is also enhanced. Cracks observed on grain boundary primary carbides allow establishing a rough damage model. The crack initiation within the HCCS alloy is strongly dependent on the temperature, the externally applied stress, and the matrix strength and composition.

  17. Active control of compressible flows on a curved surface

    NASA Technical Reports Server (NTRS)

    Maestrello, L.; Parikh, P.; Bayliss, A.; Turkel, E.

    1985-01-01

    The effect of localized, time periodic surface heating and cooling over a curved surface is studied. This is a mechanism for the active control of unstable disturbances by phase cancellation and reinforcement. It is shown that the pressure gradient induced by the curvature significantly enhances the effectiveness of this form of active control. In particular, by appropriate choice of phase, active surface heating can completely stabilize and unstable wave.

  18. Mosquito noise in MPEG-compressed video: test patterns and metrics

    NASA Astrophysics Data System (ADS)

    Fenimore, Charles P.; Libert, John M.; Roitman, Peter

    2000-06-01

    Mosquito noise is a time dependent video compression impairment in which the high frequency spatial detail in video images having crisp edges is aliased intermittently. A new synthetic test pattern of moving spirals or circles is described which generates mosquito noise (MN) under Motion Pictures Expert Group (MPEG) compression. The spiral pattern is one of several NIST-developed patterns designed to stress specific features of compression based on motion estimation and quantization. The 'Spirals' pattern has several spirals or circles superimposed on a uniform background. The frames are filtered to avoid interline flicker which may be confounded with MN. Motion of the spirals and changing luminance of the background can be included to reduce the correlation between successive frames. Unexpectedly, even a static pattern of spirals can induce mosquito noise due to the stochastic character of the encoder. We consider metrics which are specific to the impairment being measured. For mosquito noise, we examine two separable detectors: each consists of a temporal (frame-to-frame) computation applied to the output of a spatial impairment detector which is applied to each frame. The two spatial detectors are: FLATS, which detects level 8 X 8 pixel image blocks; and the root-mean-square (RMS) applied to the image differences between original and compressed frames. The test patterns are encoded at low bit rates. We examine the measured mosquito noise as a function of the Group-of-Pictures (GOP) pattern in the MPEG-2 encoding and find that the GOP structure defines the periodicities of the MN.

  19. Upgrade of the SLAC SLED II Pulse Compression System Based on Recent High Power Tests

    SciTech Connect

    Vlieks, A.E.; Fowkes, W.R.; Loewen, R.J.; Tantawi, S.G.; /SLAC

    2011-09-06

    In the Next Linear Collider (NLC) it is expected that the high power rf components be able to handle peak power levels in excess of 400 MW. We present recent results of high power tests designed to investigate the RF breakdown limits of the X-band pulse compression system used at SLAC. (SLED-II). Results of these tests show that both the TE{sub 01}-TE{sub 10} mode converter and the 4-port hybrid have a maximum useful power limit of 220-250 MW. Based on these tests, modifications of these components have been undertaken to improve their peak field handling capability. Results of these modifications will be presented. As part of an international effort to develop a new 0.5-1.5 TeV electron-positron linear collider for the 21st century, SLAC has been working towards a design, referred to as 'The Next Linear Collider' (NLC), which will operate at 11.424 GHz and utilize 50-75 MW klystrons as rf power sources. One of the major challenges in this design, or any other design, is how to generate and efficiently transport extremely high rf power from a source to an accelerator structure. SLAC has been investigating various methods of 'pulse compressing' a relatively wide rf pulse ({ge} 1 {mu}s) from a klystron into a narrower, but more intense, pulse. Currently a SLED-II pulse compression scheme is being used at SLAC in the NLC Test Accelerator (NLCTA) and in the Accelerator Structures Test Area (ASTA) to provide high rf power for accelerator and component testing. In ASTA, a 1.05 {mu}s pulse from a 50 MW klystron was successfully pulse compressed to 205 MW with a pulse width of 150 ns. Since operation in NLC will require generating and transporting rf power in excess of 400 MW it was decided to test the breakdown limits of the SLED-II rf components in ASTA with rf power up to the maximum available of 400 MW. This required the combining of power from two 50 MW klystrons and feeding the summed power into the SLED-II pulse compressor. Results from this experiment demonstrated

  20. Active SWIR laboratory testing methodology

    NASA Astrophysics Data System (ADS)

    Webb, Curtis M.; White, Steve; Rich, Brian

    2013-06-01

    Active Short Wave InfraRed (SWIR) imaging presents unique challenges to laboratory testing. It is always important to have laboratory testing that will directly relate to field performance. This paper will present the modeling and corresponding laboratory testing that was developed for these types of systems. The paper will present the modeling that was used to derive the lab metric used for verification testing of the system and provide details into the design of the lab equipment that was necessary to ensure accurate lab testing. The Noise Limited Resolution (NLR) test, first developed for low light imaging systems in the 1960s, serves as the basic lab metric for the evaluation of the active SWIR system. This test serves well for a quick test (go-no go) and is used to evaluate this system during production testing. The test derivation will be described and shown how it relates to the modeling results. The test equipment developed by Santa Barbara InfraRed (SBIR) for this application allows for accurate uniform radiance levels from an integrating sphere for both 1.06um and 1.57um imaging applications. The source has the ability to directly mimic any laser system and can provide pulsed laser source radiation from 20 nanoseconds to 500 nanoseconds resulting in levels from 0.4 to 85 nJ/cm2/sr, peak radiance levels. The light source can be triggered to replicate a laser return at any range from 100m to 100,000m. Additionally, the source provides the ability to output Mid Wave IR (MWIR) illumination through the use of a small extended area IR source in the integrating sphere. This is useful for boresighting the active SWIR sensor with other sensors such as Forward Looking IR (FLIR).

  1. An Elevated-Temperature Tension-Compression Test and Its Application to Magnesium AZ31B

    NASA Astrophysics Data System (ADS)

    Piao, Kun

    Many metals, particularly ones with HCP crystal structures, undergo deformation by combinations of twinning and slip, the proportion of which depends on variables such as temperature and strain rate. Typical techniques to reveal such mechanisms rely on metallography, x-ray diffraction, or electron optics. Simpler, faster, less expensive mechanical tests were developed in the current work and applied to Mg AZ31B. An apparatus was designed, simulated, optimized, and constructed to enable the large-strain, continuous tension/compression testing of sheet materials at elevated temperature. Thermal and mechanical FE analyses were used to locate cartridge heaters, thus enabling the attainment of temperatures up to 350°C within 15 minutes of start-up, and ensuring temperature uniformity throughout the gage length within 8°C. The low-cost device also makes isothermal testing possible at strain rates higher than corresponding tests in air. Analysis was carried out to predict the attainable compressive strains using novel finite element (FE) modeling and a single parameter characteristic of the machine and fixtures. The limits of compressive strain vary primarily with the material thickness and the applied-side-force-to-material-strength ratio. Predictions for a range of sheet alloys with measured buckling strains from -0.04 to -0.17 agreed within a standard deviation of 0.025 (0.015 excluding one material that was not initially flat). In order to demonstrate the utility of the new method, several sheet materials were tested over a range of temperatures. Some of the data obtained is the first of its kind. Magnesium AZ31B sheets were tested at temperatures up to 250°C with strain rate of 0.001/s. The inflected stress-strain curve observed in compression at room temperature disappeared between 125°C and 150°C, corresponding to the suppression of twinning, and suggesting a simple method for identifying the deformation mechanism transition temperature. The temperature

  2. Effects of wearing compression garments on thermoregulation during simulated team sport activity in temperate environmental conditions.

    PubMed

    Houghton, Laurence A; Dawson, Brian; Maloney, Shane K

    2009-03-01

    Anecdotal evidence suggests compression garments (CGs) are being worn underneath normal playing attire during team sports. Wearing CGs as a baselayer could possibly increase heat storage, and so this field study investigated the effects of wearing CGs, comprising knee-length shorts and short-sleeved top underneath normal match-day attire (COMP), versus normal match-day attire alone (NORM) on thermoregulation during simulated team sport activity. Ten match-fit field hockey players twice performed 4x15min exercise bouts consisting of repeated cycles of intermittent, varied-intensity 20m shuttle running (Loughborough intermittent shuttle test), once in COMP and once in NORM. Testing was conducted in an indoor gymnasium (ambient conditions: approximately 17 degrees C, approximately 60% relative humidity). Participants acted as their own controls. Heart rate (HR), 15m sprint time, ratings of perceived exertion (RPE), blood lactate concentration, sweat rate and body core temperature (T(core)) were similar between trials (p>0.05). Mean skin temperature (T(skin)) was significantly higher in COMP than NORM (p<0.05). Overall, CGs worn as a baselayer during simulated team sport exercise in temperate ambient conditions had no thermoregulatory benefits nor any detrimental effects on T(core), physiological performance or dehydration. However, the higher T(skin) may affect individual preference for wearing CGs as an undergarment during team sports. PMID:18078787

  3. Digital image correlation used to analyze a brick under compression test

    NASA Astrophysics Data System (ADS)

    Saldaña Heredia, Alonso; Márquez Aguilar, Pedro A.; Molina Ocampo, Arturo; Zamudio Lara, Álvaro

    2015-08-01

    In mechanics of materials it is important to know the stress-strain relation of each material in order to understand their behaviour under different loads. The brick is one of the most used materials in structural mechanics and they are always under loads. This work is implemented using one beam and the speckles created by its reflection. Strain field measurement with noninvasive techniques is needed in order to sense rubber-like materials. We present an experimental approach that describes the mechanical behavior of structural materials under compression tests, which are done in a universal testing machine. In this work we show an evaluation of the displacement field obtained by digital image correlation allowing us to evaluate the heterogeneous strain field evolution observed during these test.

  4. Tests of graphite/polyimide sandwich panels in uniaxial edgewise compression

    NASA Technical Reports Server (NTRS)

    Camarda, C. J.

    1980-01-01

    The local and general buckling behavior of graphite/polyimide sandwich panels simply supported along all four edges and loaded in uniaxial edgewise compression were investigated. Material properties of sandwich panel constituents (adhesive and facings) were determined from flatwise tension and sandwich beam flexure tests. Buckling specimens were 30.5 by 33 cm, had quasi-isotropic, symmetric facings, and a glass/polyimide honeycomb core. Core thicknesses were varied and three panels of each thickness were tested at room temperature to investigate failure modes and corresponding buckling loads. Specimens 0.635 cm thick failed by overall buckling at loads close to the analytically predicted buckling load; all other panels failed by face wrinkling. Results of the wrinkling tests indicated that several buckling formulas were unconservative and therefore not suitable for design purposes; a recommended wrinkling equation is presented.

  5. An evaluation of the sandwich beam in four-point bending as a compressive test method for composites

    NASA Technical Reports Server (NTRS)

    Shuart, M. J.; Herakovich, C. T.

    1978-01-01

    The experimental phase of the study included compressive tests on HTS/PMR-15 graphite/polyimide, 2024-T3 aluminum alloy, and 5052 aluminum honeycomb at room temperature, and tensile tests on graphite/polyimide at room temperature, -157 C, and 316 C. Elastic properties and strength data are presented for three laminates. The room temperature elastic properties were generally found to differ in tension and compression with Young's modulus values differing by as much as twenty-six percent. The effect of temperature on modulus and strength was shown to be laminate dependent. A three-dimensional finite element analysis predicted an essentially uniform, uniaxial compressive stress state in the top flange test section of the sandwich beam. In conclusion, the sandwich beam can be used to obtain accurate, reliable Young's modulus and Poisson's ratio data for advanced composites; however, the ultimate compressive stress for some laminates may be influenced by the specimen geometry.

  6. Active RF Pulse Compression using Electrically Controlled Semiconductor Switches

    SciTech Connect

    Guo, J.; Tantawi, S.G.; /SLAC

    2008-01-30

    In this paper, we will present our recent results on the research of the ultra-fast high power RF switches based on silicon. We have developed a switch module at X-band which can use a silicon window as the switch. The switching is realized by generation of carriers in the bulk silicon. The carriers can be generated electrically or/and optically. The electrically controlled switches use PIN diodes to inject carrier. We have built the PIN diode switches at X-band, with <300ns switching time. The optically controlled switches use powerful lasers to excite carriers. By combining the laser excitation and electrical carrier generation, significant reduction in the required power of both the laser and the electrical driver is expected. High power test is under going.

  7. Investigation of Nonlinear Site Response and Seismic Compression from Case History Analysis and Laboratory Testing

    NASA Astrophysics Data System (ADS)

    Yee, Eric

    In this thesis I address a series of issues related to ground failure and ground motions during earthquakes. A major component is the evaluation of cyclic volumetric strain behavior of unsaturated soils, more commonly known as seismic compression, from advanced laboratory testing. Another major component is the application of nonlinear and equivalent linear ground response analyses to large-strain problems involving highly nonlinear dynamic soil behavior. These two components are merged in the analysis of a truly unique and crucial field case history of nonlinear site response and seismic compression. My first topic concerns dynamic soil testing for relatively small strain dynamic soil properties such as threshold strains, gammatv. Such testing is often conducted using specialized devices such as dual-specimen simple-shear, as devices configured for large strain testing produce noisy signals in the small strain range. Working with a simple shear device originally developed for large-strain testing, I extend its low-strain capabilities by characterizing noisy signals and utilizing several statistical methods to extract meaningful responses in the small strain range. I utilize linear regression of a transformed variable to estimate the cyclic shear strain from a noisy signal and the confidence interval on its amplitude. I utilize Kernel regression with the Nadaraya-Watson estimator and a Gaussian kernel to evaluate vertical strain response. A practical utilization of these techniques is illustrated by evaluating threshold shear strains for volume change with a procedure that takes into account uncertainties in the measured shear and vertical strains. My second topic concerns the seismic compression characteristics of non-plastic and low-plasticity silty sands with varying fines content (10 ≤ FC ≤ 60%). Simple shear testing was performed on various sand-fines mixtures at a range of modified Proctor relative compaction levels ( RC) and degrees-of-saturation (S

  8. Edgewise Compression Testing of STIPS-0 (Structurally Integrated Thermal Protection System)

    NASA Technical Reports Server (NTRS)

    Brewer, Amy R.

    2011-01-01

    The Structurally Integrated Thermal Protection System (SITPS) task was initiated by the NASA Hypersonics Project under the Fundamental Aeronautics Program to develop a structural load-carrying thermal protection system for use in aerospace applications. The initial NASA concept for SITPS consists of high-temperature composite facesheets (outer and inner mold lines) with a light-weight insulated structural core. An edgewise compression test was performed on the SITPS-0 test article at room temperature using conventional instrumentation and methods in order to obtain panel-level mechanical properties and behavior of the panel. Three compression loadings (10, 20 and 37 kips) were applied to the SITPS-0 panel. The panel behavior was monitored using standard techniques and non-destructive evaluation methods such as photogrammetry and acoustic emission. The elastic modulus of the SITPS-0 panel was determined to be 1.146x106 psi with a proportional limit at 1039 psi. Barrel-shaped bending of the panel and partial delamination of the IML occurred under the final loading.

  9. Brain activity monitoring by compressed spectral array during deep hypothermic circulatory arrest in acute aortic dissection surgery

    PubMed Central

    Budniak, Wiktor; Buczkowski, Piotr; Perek, Bartłomiej; Walczak, Maciej; Tomczyk, Jadwiga; Katarzyński, Sławomir; Jemielity, Marek

    2014-01-01

    Introduction Monitoring the central nervous system during aortic dissection repair may improve the understanding of the intraoperative changes related to its bioactivity. Aim The aim of the study was to evaluate the influence of deep hypothermia on intraoperative brain bioactivity measured by the compressed spectral array (CSA) method and to assess the influence of the operations on postoperative cognitive function. Material and methods The study enrolled 40 patients (31 men and 9 women) at the mean age of 60.2 ± 8.6 years, diagnosed with acute aortic dissection. They underwent emergency operations in deep hypothermic circulatory arrest (DHCA). During the operations, brain bioactivity was monitored with the compressed spectral array method. Results There were no intraoperative deaths. Electrocerebral silence during DHCA was observed in 31 patients (74%). The lowest activity was observed during DHCA: it was 0.01 ± 0.05 nW in the left hemisphere and 0.01 ± 0.03 nW in the right hemisphere. The postoperative results of neurological tests deteriorated statistically significantly (26.9 ± 1.7 points vs. 22.0 ± 1.7 points; p < 0.001), especially among patients who exhibited brain activity during DHCA. Conclusions The compressed spectral array method is clinically useful in monitoring brain bioactivity during emergency operations of acute aortic dissections. Electrocerebral silence occurs in 75% of patients during DHCA. The cognitive function of patients deteriorates significantly after operations with DHCA. PMID:26336458

  10. Cyclic tension compression testing of AHSS flat specimens with digital image correlation system

    NASA Astrophysics Data System (ADS)

    Knoerr, Lay; Sever, Nimet; McKune, Paul; Faath, Timo

    2013-12-01

    A cyclic tension-compression testing program was conducted on flat specimens of TPN-W®780 (Three Phase Nano) and DP980 (Dual Phase) Advanced High Strength Steels (AHSS). This experimental method was enabled utilizing an anti-buckling clamping device performed in a test machine, and the surface strains along the thickness edge are measured with a three-dimensional Digital Image Correlation (DIC) system. The in-plane pre-strain and reversed strain values, at specified strain rates, are investigated to observe the potential plastic flow and the nonlinear strain hardening behavior of the materials. The validity of the test results is established with the monotonic tension tests, to substantiate the true stress-strain curves corrected for the frictional and biaxial stresses induced by the clamping device. A process method for analyzing the correction using a macro script is shown to simplify the output of the true stress-strain results for material model calibration. An in progress study to validate the forming and spring-back predictive capabilities of a calibrated TPN-W®780 complex material model to an actual stamping of an automotive component will demonstrate the usefulness of the experimental cyclic test method. Suggestions to improve the testing, strain analysis and calibration of the model parameters are proposed for augmented use of this test method.

  11. Controls on radon emission from granite as evidenced by compression testing to failure

    NASA Astrophysics Data System (ADS)

    Koike, Katsuaki; Yoshinaga, Tohru; Suetsugu, Kenta; Kashiwaya, Koki; Asaue, Hisafumi

    2015-10-01

    A set of uniaxial compression tests of granite specimens taken from five localities across Japan was conducted to identify the factors controlling the quantity of radon (Rn) emission (sum of 222Rn and 220Rn) during compression and failure. An α-scintillation detector and a gas flow unit were installed with a testing machine to enable continuous measurement of Rn emissions. Common to all specimens, Rn emissions remained at or slightly declined from the background level after the start of loading; this is similar to the natural phenomenon of decline in groundwater-dissolved Rn before an earthquake. Closure of original microcracks is the most likely cause of the initial Rn decline. Then, Rn emissions begin to increase at 46-57 per cent stress level to the uniaxial compressive strength, and continue to increase even after the failure of specimen. This commencement stress level is close to the general stress level at outbreak of acoustic emissions caused by the development and connection of microcracks. The Rn increase after failure is similar to a phenomenon observed in aftershocks, which may originate from the enhancement of Rn emanations from grains due to the large increase in total surface area and stress release. In addition to the initial radioelement content in rock, the failure pattern (conjugate shear versus longitudinal tensile type), compressive strength, and grain size are possible control factors of the maximum quantity of Rn emissions induced by failure. This maximum may also be affected by the development velocity of the emanation area, which is related to the Rn emanation fraction, associated with the fragmentation. In addition to the magnitude of an earthquake and its hypocentre distance to Rn detectors, the magnitude of increase in Rn concentration in soil gas and groundwater before, during, and after an earthquake in crystalline rocks depends on the intrinsic radioelement content, the mineral texture, and the mechanical properties of rocks. Rock

  12. Design of a miniature hydraulic compression load frame for microdiffraction tests at the Advanced Photon Source.

    SciTech Connect

    Shu, D.; Varma, R.; Krasnicki, S.; Sinha, S.

    1999-10-11

    In support of the x-ray synchrotrons radiation multidiffraction project of Los Alamos National Laboratory at the Advanced Photon Source (APS), we have designed and fabricated a miniature hydraulic compression load frame with 20000 N load capacity for metal specimen tests at the APS. The compact design allows the load frame to sit on the center of a 6-circle goniometer with six degrees of freedom and maximum solid angle accessibility for the incoming x-ray beam and diffraction beam detectors. A set of compact precision stages with submicron resolution has been designed for the load frame positioning to compensate the sample internal elastic and/or plastic deformation during the loading process. The system design, specifications, and test results are presented.

  13. Compressed air demand-type firefighter's breathing system, volume 1. [design analysis and performance tests

    NASA Technical Reports Server (NTRS)

    Sullivan, J. L.

    1975-01-01

    The commercial availability of lightweight high pressure compressed air vessels has resulted in a lightweight firefighter's breathing apparatus. The improved apparatus, and details of its design and development are described. The apparatus includes a compact harness assembly, a backplate mounted pressure reducer assembly, a lightweight bubble-type facemask with a mask mounted demand breathing regulator. Incorporated in the breathing regulator is exhalation valve, a purge valve and a whistle-type low pressure warning that sounds only during inhalation. The pressure reducer assembly includes two pressure reducers, an automatic transfer valve and a signaling device for the low pressure warning. Twenty systems were fabricated, tested, refined through an alternating development and test sequence, and extensively examined in a field evaluation program. Photographs of the apparatus are included.

  14. The evaluation of upper body muscle activity during the performance of external chest compressions in simulated hypogravity

    NASA Astrophysics Data System (ADS)

    Krygiel, Rebecca G.; Waye, Abigail B.; Baptista, Rafael Reimann; Heidner, Gustavo Sandri; Rehnberg, Lucas; Russomano, Thais

    2014-04-01

    BACKGROUND: This original study evaluated the electromyograph (EMG) activity of four upper body muscles: triceps brachii, erector spinae, upper rectus abdominis, and pectoralis major, while external chest compressions (ECCs) were performed in simulated Martian hypogravity using a Body Suspension Device, counterweight system, and standard full body cardiopulmonary resuscitation (CPR) mannequin. METHOD: 20 young, healthy male subjects were recruited. One hundred compressions divided into four sets, with roughly six seconds between each set to indicate 'ventilation', were performed within approximately a 1.5 minute protocol. Chest compression rate, depth and number were measured along with the subject's heart rate (HR) and rating of perceived exertion (RPE). RESULTS: All mean values were used in two-tailed t-tests using SPSS to compare +1 Gz values (control) versus simulated hypogravity values. The AHA (2005) compression standards were maintained in hypogravity. RPE and HR increased by 32% (p < 0.001) and 44% (p = 0.002), respectively, when ECCs were performed during Mars simulation, in comparison to +1 Gz. In hypogravity, the triceps brachii showed significantly less activity (p < 0.001) when compared with the other three muscles studied. The comparison of all the other muscles showed no difference at +1 Gz or in hypogravity. CONCLUSIONS: This study was among the first of its kind, however several limitations were faced which hopefully will not exist in future studies. Evaluation of a great number of muscles will allow space crews to focus on specific strengthening exercises within their current training regimes in case of a serious cardiac event in hypogravity.

  15. The Next Linear Collider Test Accelerator's RF Pulse Compression And Transmission

    SciTech Connect

    Tantawi, S.G.; Adelphson, C.; Holmes, S.; Lavine, Theodore L.; Loewen, R.J.; Nantista, C.; Pearson, C.; Pope, R.; Rifkin, J.; Ruth, R.D.; Vlieks, A.E.; /SLAC

    2011-09-14

    The overmoded rf transmission and pulsed power compression system for SLAC's Next Linear Collider (NLC) program requires a high degree of transmission efficiency and mode purity to be economically feasible. To this end, a number of new, high power components and systems have been developed at X-band, which transmit rf power in the low loss, circular TE01 mode with negligible mode conversion. In addition, a highly efficient SLED-II* pulse compressor has been developed and successfully tested at high power. The system produced a 200 MW, 250 ns wide pulse with a near-perfect flat-top. In this paper we describe the design and test results of the high power pulse compression system using SLED-II. The NLC rf systems use low loss highly over-moded circular waveguides operating in the TE01 mode. The efficiency of the systems is sensitive to the mode purity of the mode excited inside these guides. We used the so called flower petal mode transducer [2] to excite the TE01 mode. This type of mode transducer is efficient, compact and capable of handling high levels of power. To make more efficient systems, we modified this device by adding several mode selective chokes to act as mode purifiers. To manipulate the rf signals we used these modified mode converters to convert back and forth between over-moded circular waveguides and single-moded WR90 rectangular waveguides. Then, we used the relatively simple rectangular waveguide components to do the actual manipulation of rf signals. For example, two mode transducers and a mitered rectangular waveguide bend comprise a 90 degree bend. Also, a magic tee and four mode transducers would comprise a four-port-hybrid, etc. We will discuss the efficiency of an rf transport system based on the above methodology. We also used this methodology in building the SLEDII pulse compression system. At SLAC we built 4 of these pulse systems. In this paper we describe the SLEDII system and compare the performance of these 4 systems at SLAC. We

  16. Active Matrix OLED Test Report

    NASA Technical Reports Server (NTRS)

    Salazar, George

    2013-01-01

    This report focuses on the limited environmental testing of the AMOLED display performed as an engineering evaluation by The NASA Johnson Space Center (JSC)-specifically. EMI. Thermal Vac, and radiation tests. The AMOLED display is an active-matrix Organic Light Emitting Diode (OLED) technology. The testing provided an initial understanding of the technology and its suitability for space applications. Relative to light emitting diode (LED) displays or liquid crystal displays (LCDs), AMOLED displays provide a superior viewing experience even though they are much lighter and smaller, produce higher contrast ratio and richer colors, and require less power to operate than LCDs. However, AMOLED technology has not been demonstrated in a space environment. Therefore, some risks with the technology must be addressed before they can be seriously considered for human spaceflight. The environmental tests provided preliminary performance data on the ability of the display technology to handle some of the simulated induced space/spacecraft environments that an AMOLED display will see during a spacecraft certification test program. This engineering evaluation is part of a Space Act Agreement (SM) between The NASA/JSC and Honeywell International (HI) as a collaborative effort to evaluate the potential use of AMOLED technology for future human spaceflight missions- both government-led and commercial. Under this SM, HI is responsible for doing optical performance evaluation, as well as temperature and touch screen studies. The NASA/JSC is responsible for performing environmental testing comprised of EMI, Thermal Vac, and radiation tests. Additionally, as part of the testing, limited optical data was acquired to assess performance as the display was subjected to the induced environments. The NASA will benefit from this engineering evaluation by understanding AMOLED suitability for future use in space as well as becoming a smarter buyer (or developer) of the technology. HI benefits

  17. Thermomechanical behavior of thermoset shape memory polymer programmed by cold-compression: Testing and constitutive modeling

    NASA Astrophysics Data System (ADS)

    Li, Guoqiang; Xu, Wei

    2011-06-01

    Programming is a key process for thermally activated stress or strain recovery of shape memory polymers (SMPs). Typically, programming requires an initial heating above the glass transition temperature ( Tg), subsequent cooling below Tg and removal of the applied load, in order to fix a temporary shape. This work adopted a new approach to program thermoset SMPs directly at temperatures well below Tg, which effectively simplified the shape fixing process. 1-D compression programming below Tg and free shape recovery of a thermoset SMP were experimentally investigated. Functional stability of the shape fixity under various environmental attacks was also experimentally evaluated. A mechanism-based thermoviscoelastic-thermoviscoplastic constitutive model incorporating structural and stress relaxation was then developed to predict the nonlinear shape memory behavior of the SMP trained below Tg. Comparison between the prediction and the experiment showed good agreement. The structure dependence of the thermomechanical behavior of the SMP was further discussed through a parametric study per the validated constitutive model. This study validates that programming by cold-compression is a viable alternative for thermally responsive thermoset SMPs.

  18. Analysis and test of superplastically formed titanium hat-stiffened panels under compression

    NASA Technical Reports Server (NTRS)

    Davis, Randall C.; Royster, Dick M.; Bales, Thomas T.

    1987-01-01

    Four hat-stiffened titanium panels with two different stiffener configurations were fabricated by superplastic forming/weld brazing and tested under a moderately heavy compressive load. The panels had the same overall dimensions but differed in the shape of the hat-stiffener webs; three panels had stiffeners with flat webs and the other panel had stiffeners with beaded webs. Analysis indicated that the local buckling strain of the flat stiffener web was considerably lower than the general panel buckling strain or cap buckling strain. The analysis also showed that beading the webs of the hat stiffeners removed them as the critical element for local buckling and improved the buckling strain of the panels. The analytical extensional stiffness and failure loads compared very well with experimental results.

  19. Design, fabrication and test of lightweight shell structure. [axial compression loads and torsion stress

    NASA Technical Reports Server (NTRS)

    Lager, J. R.

    1975-01-01

    A cylindrical shell structure 3.66 m (144 in.) high by 4.57 m (180 in.) diameter was designed using a wide variety of materials and structural concepts to withstand design ultimate combined loading 1225.8 N/cm (700 lb/in.) axial compression and 245.2 N/cm (140 lb/in.) torsion. The overall cylinder geometry and design loading are representative of that expected on a high performance space tug vehicle. The relatively low design load level results in designs that use thin gage metals and fibrous-composite laminates. Fabrication and structural tests of small panels and components representative of many of the candidate designs served to demonstrate proposed fabrication techniques and to verify design and analysis methods. Three of the designs evaluated, honeycomb sandwich with aluminum faceskins, honeycomb sandwich with graphite/epoxy faceskins, and aluminum truss with fiber-glass meteoroid protection layers, were selected for further evaluation.

  20. 49 CFR Appendix A to Part 180 - Internal Self-closing Stop Valve Emergency Closure Test for Liquefied Compressed Gases

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Internal Self-closing Stop Valve Emergency Closure..., App. A Appendix A to Part 180—Internal Self-closing Stop Valve Emergency Closure Test for Liquefied Compressed Gases 1. In performing this test, all internal self-closing stop valves must be opened....

  1. 49 CFR Appendix A to Part 180 - Internal Self-closing Stop Valve Emergency Closure Test for Liquefied Compressed Gases

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... Part 180—Internal Self-closing Stop Valve Emergency Closure Test for Liquefied Compressed Gases 1. In performing this test, all internal self-closing stop valves must be opened. Each emergency discharge control... 49 Transportation 3 2014-10-01 2014-10-01 false Internal Self-closing Stop Valve Emergency...

  2. Material test machine for tension-compression tests at high temperature

    DOEpatents

    Cioletti, Olisse C.

    1988-01-01

    Apparatus providing a device for testing the properties of material specimens at high temperatures and pressures in controlled water chemistries includes, inter alia, an autoclave housing the specimen which is being tested. The specimen is connected to a pull rod which couples out of the autoclave to an external assembly which includes one or more transducers, a force balance chamber and a piston type actuator. The pull rod feeds through the force balance chamber and is compensated thereby for the pressure conditions existing within the autoclave and tending to eject the pull rod therefrom. The upper end of the push rod is connected to the actuator through elements containing a transducer comprising a linear variable differential transformer (LVDT). The housing and coil assembly of the LVDT is coupled to a tube which runs through a central bore of the pull rod into the autoclave where it is connected to one side of the specimen. The movable core of the LVDT is coupled to a stem which runs through the tube where it is then connected to the other side of the specimen through a coupling member. A transducer in the form of a load cell including one or more strain gages is located on a necked-down portion of the upper part of the pull rod intermediate the LVDT and force balance chamber.

  3. Validation of a Compression Mass Gauge using ground tests for liquid propellant mass measurements

    NASA Astrophysics Data System (ADS)

    Fu, Juan; Chen, Xiaoqian; Huang, Yiyong; Li, Xiaolong

    2014-05-01

    To properly estimate orbital lifetimes and predict the maneuverability of spacecraft, the remaining liquid propellant mass must be accurately known at every moment of a space mission. This paper studies the Compression Mass Gauge (CMG) method to determine the mass of liquid contained in a tank in a low-gravity environment with high accuracy. CMG is a thermodynamic method used to determine the quantity of liquid by measuring the gas pressure change when the tank volume changes, and has been previously theoretically and experimentally studied by researchers. The primary objective of this investigation is to explore the effects of attitude disturbance and the spacecraft thermal environment on the accuracy of the method. A ground test system, consisting of several test apparatuses, was fabricated and described as part of this study. The test results and analyses indicate that the CMG performs well and has an accuracy of ±1%. Additionally, demonstrations were performed to show that measurement errors do not increase drastically or exceed ±1% when the test system is vibrated to simulate the tank being perturbed as a result of an attitude disturbance. Liquid sloshing resonance was found to have a significant effect on the gauging accuracy. Measurements in a real thermal environment in which heat transfers into and out of the propellant tank were also conducted. The results show that the gauging accuracy is acceptable for normal liquid propellant. Furthermore, theoretical research shows that heat leakage has a significant influence on cryogenic propellant mass gauging.

  4. Compressed-air energy storage field test using the aquifer at Pittsfield, Illinois

    SciTech Connect

    Istvan, J.A.; Pereira, J.C.; Roark, P.; Bakhtiari, H. )

    1990-02-01

    This report describes the design, construction, and operation of a field experiment to examine feasibility of full-scale compressed air energy storage (CAES) within aquifer reservoirs. A summary of data obtained and the conclusions from the field experiment are presented. Two injection/withdrawal wells, two instrument wells, and four logging/sampling wells were drilled and cored. Air was injected in the St. Peter Sandstone to create an air bubble which was cycled with ambient and elevated temperature air in the injection withdrawal pattern contemplated for CAES installations. At its peak content of 111.75 {times} 10{sup 6} scf, the air bubble was 30 ft thick at the I/W well area and reached 18 ft in thickness at a distance of 686 ft from the I/W well. Three post-test core wells were drilled and cored. The caprock, reservoir, and formation water were sampled and analyzed prior to and after exposure to compressed air and associated water. Samples of stored air were collected and analyzed. Items of interest were degree of liquid entrance into flowing well, effects in aquifer of increased air temperature, and changes in oxygen content of air. Prior to plugging and abandoning the well field, an additional well was drilled and cored, outside the air bubble. This work is part of the continuing research by EPRI to investigate the geochemical oxidation process. Reservoir engineering and utilization of geologic media for storing air has many complexities, but it has useable experience from successful natural gas storage. The design, construction, and testing at Pittsfield demonstrates that orientation toward useage of an aquifer air storage facility can be performed successfully. The disappearance of oxygen needs attention for seasonal storage of air but should not dampen enthusiasm for weekly or daily storage cycles.

  5. Fitted hyperelastic parameters for Human brain tissue from reported tension, compression, and shear tests.

    PubMed

    Moran, Richard; Smith, Joshua H; García, José J

    2014-11-28

    The mechanical properties of human brain tissue are the subject of interest because of their use in understanding brain trauma and in developing therapeutic treatments and procedures. To represent the behavior of the tissue, we have developed hyperelastic mechanical models whose parameters are fitted in accordance with experimental test results. However, most studies available in the literature have fitted parameters with data of a single type of loading, such as tension, compression, or shear. Recently, Jin et al. (Journal of Biomechanics 46:2795-2801, 2013) reported data from ex vivo tests of human brain tissue under tension, compression, and shear loading using four strain rates and four different brain regions. However, they do not report parameters of energy functions that can be readily used in finite element simulations. To represent the tissue behavior for the quasi-static loading conditions, we aimed to determine the best fit of the hyperelastic parameters of the hyperfoam, Ogden, and polynomial strain energy functions available in ABAQUS for the low strain rate data, while simultaneously considering all three loading modes. We used an optimization process conducted in MATLAB, calling iteratively three finite element models developed in ABAQUS that represent the three loadings. Results showed a relatively good fit to experimental data in all loading modes using two terms in the energy functions. Values for the shear modulus obtained in this analysis (897-1653Pa) are in the range of those presented in other studies. These energy-function parameters can be used in brain tissue simulations using finite element models. PMID:25446271

  6. Mechanical properties of bulk single crystalline nanoporous gold investigated by millimetre-scale tension and compression testing

    NASA Astrophysics Data System (ADS)

    Briot, Nicolas J.; Kennerknecht, Tobias; Eberl, Christoph; Balk, T. John

    2014-03-01

    In this work, the mechanical behaviour of millimetre-scale, bulk single crystalline, nanoporous gold at room temperature is reported for the first time. Tension and compression tests were performed with a custom-designed test system that accommodates small-scale samples. The absence of grain boundaries in the specimens allowed measurement of the inherent strength of millimetre-scale nanoporous gold in tension. The elastic modulus and strength values in tension and compression were found to be significantly lower than values measured with nanoindentation-based techniques and previously reported in the literature, but close to those reported for millimetre-scale polycrystalline samples tested using traditional compression techniques. Fracture toughness was found to be very low, in agreement with the macroscopic brittleness of nanoporous gold, but this is due to the localization of deformation to a narrow zone of ligaments, which individually exhibit significant plasticity and necking.

  7. Subclinical respiratory dysfunction in chronic cervical cord compression: a pulmonary function test correlation.

    PubMed

    Bhagavatula, Indira Devi; Bhat, Dhananjaya I; Sasidharan, Gopalakrishnan M; Mishra, Rakesh Kumar; Maste, Praful Suresh; Vilanilam, George C; Sathyaprabha, Talakkad N

    2016-06-01

    OBJECTIVE Respiratory abnormalities are well documented in acute spinal cord injury; however, the literature available for respiratory dysfunction in chronic compressive myelopathy (CCM) is limited. Respiratory dysfunction in CCM is often subtle and subclinical. The authors studied the pattern of respiratory dysfunction in patients with chronic cord compression by using spirometry, and the clinical and surgical implications of this dysfunction. In this study they also attempted to address the postoperative respiratory function in these patients. METHODS A prospective study was done in 30 patients in whom cervical CCM due to either cervical spondylosis or ossification of the posterior longitudinal ligament (OPLL) was diagnosed. Thirty age-matched healthy volunteers were recruited as controls. None of the patients included in the study had any symptoms or signs of respiratory dysfunction. After clinical and radiological diagnosis, all patients underwent pulmonary function tests (PFTs) performed using a standardized Spirometry Kit Micro before and after surgery. The data were analyzed using Statistical Software SPSS version 13.0. Comparison between the 2 groups was done using the Student t-test. The Pearson correlation coefficient was used for PFT results and Nurick classification scores. A p value < 0.05 was considered significant. RESULTS Cervical spondylotic myelopathy (prolapsed intervertebral disc) was the predominant cause of compression (n = 21, 70%) followed by OPLL (n = 9, 30%). The average patient age was 45.06 years. Degenerative cervical spine disease has a relatively younger onset in the Indian population. The majority of the patients (n = 28, 93.3%) had compression at or above the C-5 level. Ten patients (33.3%) underwent an anterior approach and discectomy, 11 patients (36.7%) underwent decompressive laminectomy, and the remaining 9 underwent either corpectomy with fusion or laminoplasty. The mean preoperative forced vital capacity (FVC) (65%) of the

  8. Boron-10 ABUNCL Active Testing

    SciTech Connect

    Kouzes, Richard T.; Ely, James H.; Lintereur, Azaree T.; Siciliano, Edward R.

    2013-07-09

    The Department of Energy Office of Nuclear Safeguards and Security (NA-241) is supporting the project Coincidence Counting With Boron-Based Alternative Neutron Detection Technology at Pacific Northwest National Laboratory (PNNL) for the development of a 3He proportional counter alternative neutron coincidence counter. The goal of this project is to design, build and demonstrate a system based upon 10B-lined proportional tubes in a configuration typical for 3He-based coincidence counter applications. This report provides results from testing of the active mode of the General Electric Reuter-Stokes Alternative Boron-Based Uranium Neutron Coincidence Collar (ABUNCL) at Los Alamos National Laboratory using sources and fuel pins.

  9. The Pack Method for Compressive Tests of Thin Specimens of Materials Used in Thin-Wall Structures

    NASA Technical Reports Server (NTRS)

    Aitchison, C S; Tuckerman, L B

    1939-01-01

    The strength of modern lightweight thin-wall structures is generally limited by the strength of the compression members. An adequate design of these members requires a knowledge of the compressive stress-strain graph of the thin-wall material. The "pack" method was developed at the National Bureau of Standards with the support of the National Advisory Committee for Aeronautics to make possible a determination of compressive stress-strain graphs for such material. In the pack test an odd number of specimens are assembled into a relatively stable pack, like a "pack of cards." Additional lateral stability is obtained from lateral supports between the external sheet faces of the pack and outside reactions. The tests seems adequate for many problems in structural research.

  10. Creep Testing Plastic-Bonded Explosives in Uni-axial Compression

    SciTech Connect

    Gagliardi, F J; Cunningham, B J

    2008-03-13

    High fidelity measurements of time-dependent strain in the plastic-bonded explosives LX-17-1 and PBX 9502 have been performed under constant, uni-axial, compressive load using a custom designed apparatus. The apparatus uses a combination of extensometers and linear variable differential transformers coupled with a data acquisition system, thermal controls, and gravitational loading. The materials being tested consist of a crystalline explosive material mixed with a polymeric binder. The behavior of each material is related to the type of explosive and to the percentage and type of binder. For any given plastic-bonded explosive, the creep behavior is also dependent on the stress level and test temperature. Experiments were conducted using a 3 x 3 stress-temperature matrix with a temperature range of 24 C to 70 C and with stresses ranging from 250-psi to 780-psi. Analysis of the data has shown that logarithmic curve fits provide an accurate means of quantification and facilitate a long-term predictive capability. This paper will discuss the design of the apparatus, experimental results, and analyses.

  11. Predicting the uniaxial compressive strength of cemented paste backfill from ultrasonic pulse velocity test

    NASA Astrophysics Data System (ADS)

    Yılmaz, Tekin; Ercikdi, Bayram

    2016-07-01

    The aim of this study is to investigate the predictability of the uniaxial compressive strength (UCS) of cemented paste backfill (CPB) prepared from three different tailings (Tailings T1, Tailings T2 and Tailings T3) using ultrasonic pulse velocity (UPV) test. For this purpose, 180 CPB samples with diameter × height of 5 × 10 cm (similar to NX size) prepared at different binder dosages and consistencies were subjected to the UPV and UCS tests at 7-56 days of curing periods. The effects of binder dosage and consistency on the UPV and UCS properties of CPB samples were investigated and UCS values were correlated with the corresponding UPV data. Microstructural analyses were also performed on CPB samples in order to understand the effect of microstructure (i.e. total porosity) on the UPV data. The UPV and UCSs of CPB samples increased with increasing binder dosage and reducing the consistency irrespective of the tailings type and curing periods. Changes in the mixture properties observed to have a lesser extent on the UPV properties of CPB, while, their effect on the UCS of CPB was significant. Empirical equations were produced for each mixture in order to predict the UCSs of CPB through UPV. The validity of the equations was also checked by t- and F-test. The results showed that a linear relation appeared to exist between the UPV and UCS with high correlation coefficients (r ≥ 0.79) and all models were valid by statistical analysis. Mercury intrusion porosimetry (MIP) and scanning electron microscope (SEM) analyses have revealed that the UPV properties of CPB samples were highly associated with their respective microstructural properties (i.e. total porosity). The major output of this study is that UPV test can be effectively used for a preliminary prediction of the strength of CPB.

  12. Design and fabrication of silicon carbide split furnace for high-speed compression tests up to 1573 K

    SciTech Connect

    Venugopal, S.; Mannan, S.L.; Sasidhara, S.; Prasad, Y.V.R.K. Indian Inst. of Science, Bangalore )

    1993-04-01

    A split furnace with silicon carbide heating elements that can be used for high-speed compression tests is described. It is concluded that the life of silicon carbide elements will be longer if the elements are fixed in horizontal direction. The shrinkage cracks on the refractories can be avoided if they are thin and stacked as plies. 5 refs.

  13. 49 CFR Appendix A to Part 180 - Internal Self-closing Stop Valve Emergency Closure Test for Liquefied Compressed Gases

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 3 2013-10-01 2013-10-01 false Internal Self-closing Stop Valve Emergency Closure Test for Liquefied Compressed Gases A Appendix A to Part 180 Transportation Other Regulations Relating... TRANSPORTATION (CONTINUED) CONTINUING QUALIFICATION AND MAINTENANCE OF PACKAGINGS Pt. 180, App. A Appendix A...

  14. 49 CFR Appendix A to Part 180 - Internal Self-closing Stop Valve Emergency Closure Test for Liquefied Compressed Gases

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 3 2012-10-01 2012-10-01 false Internal Self-closing Stop Valve Emergency Closure Test for Liquefied Compressed Gases A Appendix A to Part 180 Transportation Other Regulations Relating to Transportation (Continued) PIPELINE AND HAZARDOUS MATERIALS SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED)...

  15. 49 CFR Appendix A to Part 180 - Internal Self-closing Stop Valve Emergency Closure Test for Liquefied Compressed Gases

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 3 2011-10-01 2011-10-01 false Internal Self-closing Stop Valve Emergency Closure Test for Liquefied Compressed Gases A Appendix A to Part 180 Transportation Other Regulations Relating to Transportation (Continued) PIPELINE AND HAZARDOUS MATERIALS SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED)...

  16. A methodology to study crystal plasticity inside a compression test sample based on image correlation and EBSD

    SciTech Connect

    Rehrl, C.; Kleber, S.; Antretter, T.; Pippan, R.

    2011-08-15

    Modified compression tests in a coarse-grained austenitic stainless steel have been carried out in order to examine the crystal plasticity behavior for large plastic deformations. The measurements of local in-plane strains provide deeper insight into the deformation process on the local scale. These measurements are performed by digital image correlation technique (DIC) in combination with local crystal orientation measurements by using the electron backscatter diffraction technique (EBSD). Split test samples are prepared to track the strong microstructural changes during deformation, which is done incrementally in 10% steps up to 60% total macroscopic strain. The clear correlation of local strains with crystal orientation changes - e.g. in the case of mechanical twinning - permits to identify the acting deformation mechanisms. Such, experimentally determined local strain maps can be used for verification of crystal plasticity finite element method simulations (CPFEM). - Research Highlights: {yields} Method to study large strain crystal plasticity inside an austenitic FeCrNi-alloy. {yields} Correlation of local strain analyses with crystal orientation measurements. {yields} Deformation mechanism changes locally from dislocation glide to mechanical twinning. {yields} Suitable to study grain-grain interactions, slip system activation and grain boundary effects. {yields} Provide essential data for crystal plasticity FEM studies.

  17. Comment on ``Proposal of a critical test of the Navier-Stokes-Fourier paradigm for compressible fluid continua''

    NASA Astrophysics Data System (ADS)

    Felderhof, B. U.

    2013-08-01

    Recently, a critical test of the Navier-Stokes-Fourier equations for compressible fluid continua was proposed [H. Brenner, Phys. Rev. EPLEEE81539-375510.1103/PhysRevE.87.013014 87, 013014 (2013)]. It was shown that the equations of bivelocity hydrodynamics imply that a compressible fluid in an isolated rotating circular cylinder attains a nonequilibrium steady state with a nonuniform temperature increasing radially with distance from the axis. We demonstrate that statistical mechanical arguments, involving Hamiltonian dynamics and ergodicity due to irregularity of the wall, lead instead to a thermal equilibrium state with uniform temperature. This is the situation to be expected in experiment.

  18. Comment on "Proposal of a critical test of the Navier-Stokes-Fourier paradigm for compressible fluid continua".

    PubMed

    Felderhof, B U

    2013-08-01

    Recently, a critical test of the Navier-Stokes-Fourier equations for compressible fluid continua was proposed [H. Brenner, Phys. Rev. E 87, 013014 (2013)]. It was shown that the equations of bivelocity hydrodynamics imply that a compressible fluid in an isolated rotating circular cylinder attains a nonequilibrium steady state with a nonuniform temperature increasing radially with distance from the axis. We demonstrate that statistical mechanical arguments, involving Hamiltonian dynamics and ergodicity due to irregularity of the wall, lead instead to a thermal equilibrium state with uniform temperature. This is the situation to be expected in experiment. PMID:24032976

  19. Tank Tests of a Powered Model of a Compression Plane, NACA Model 171A-2

    NASA Technical Reports Server (NTRS)

    Mottard, Elmo J.; Ruggles, Robert D.

    1948-01-01

    The compression plane is intended for operation on or close to the surface of the water, and has a hull with a concave bottom which forms the upper surface of a tunnel into which air is forced under pressure to support part of the load. The results of the tests made in Langley tank no. 1 include values of the horizontal forces, trimming moment, and static pressure in the tunnel for a wide range of loads and speeds and two power conditions, and are presented in the form of curves against speed with load as a parameter. The results are scaled up to 10 times the model size for three conditions at which the model is self-propelled at a steady speed. Lift is obtained from the static pressure of air in the tunnel. In general, the ratio of the gross load to the total resistance increases with increase in load and decrease in speed. This ratio varies between l-7 and 5.7 at high speeds and has a maximum value of 7. The total resistance is nearly the same for both power conditions except at low speeds and heavy loads. No abrupt change in forces on the hull or flow around the hull occurs in. the region of zero draft. The centers of pressure are generally far aft. At the most efficient trim (1.2'), considerable bow-up moment would be required for practicable operation. There is no abrupt transition from the air-borne to the water- borne condition.

  20. A technique to achieve uniform stress distribution in compressive creep testing of advanced ceramics at high temperatures

    SciTech Connect

    Liu, K.C.; Stevens, C.O.; Brinkman, C.R.; Holshauser, N.E.

    1996-05-01

    A technique to achieve stable and uniform uniaxial compression is offered for creep testing of advanced ceramic materials at elevated temperatures, using an innovative self-aligning load-train assembly. Excellent load-train alignment is attributed to the inherent ability of a unique hydraulic universal coupler to maintain self-aligning. Details of key elements, design concept, and pricniples of operation of the self-aligning coupler are described. A method of alignment verification using a strain-gaged specimen is then discussed. Results of verification tests indicate that bending below 1.5% is routinely achievable usin the load-train system. A successful compression creep test is demonstrated using a dumbbell-shpaed Si nitride specimen tested at 1300 C for over 4000 h.

  1. Charge-exchange and fusion reaction measurements during compression experiments with neutral beam heating in the Tokamak Fusion Test Reactor

    SciTech Connect

    Kaita, R.; Heidbrink, W.W.; Hammett, G.W.; Chan, A.A.; England, A.C.; Hendel, H.W.; Medley, S.S.; Nieschmidt, E.; Roquemore, A.L.; Scott, S.D.

    1986-04-01

    Adiabatic toroidal compression experiments were performed in conjunction with high power neutral beam injection in the Tokamak Fusion Test Reactor (TFTR). Acceleration of beam ions to energies nearly twice the injection energy was measured with a charge-exchange neutral particle analyzer. Measurements were also made of 2.5 MeV neutrons and 15 MeV protons produced in fusion reactions between the deuterium beam ions and the thermal deuterium and /sup 3/He ions, respectively. When the plasma was compressed, the d(d,n)/sup 3/He fusion reaction rate increased a factor of five, and the /sup 3/He(d,p)/sup 4/He rate by a factor of twenty. These data were simulated with a bounce-averaged Fokker-Planck program, which assumed conservation of angular momentum and magnetic moment during compression. The results indicate that the beam ion acceleration was consistent with adiabatic scaling.

  2. Kinesiology Tape or Compression Sleeve Applied to the Thigh Does Not Improve Balance or Muscle Activation Before or Following Fatigue.

    PubMed

    Cavanaugh, M Tyler; Quigley, Patrick J; Hodgson, Daniel D; Reid, Jonathan C; Behm, David G

    2016-07-01

    Cavanaugh, MT, Quigley, PJ, Hodgson, DD, Reid, JC, and Behm, DG. Kinesiology tape or compression sleeve applied to the thigh does not improve balance or muscle activation before or following fatigue. J Strength Cond Res 30(7): 1992-2000, 2016-Compression sleeves (CS) and kinesiology tape (KT) are purported to enhance proprioception, however, there is substantial conflict in the literature. Because the beneficial effects of CS and KT are more evident in the literature with recovery, the objective of this study was to examine the effects of CS and KT on balance under acute nonfatigued and postfatigued conditions. Using a within-subject, repeated-measures design, 12 university participants (5 females and 7 males) performed in a random order CS, KT, and Control conditions. Two trials of each test were conducted before the application of CS or KT (pretest 1), immediately after the application (pretest 2), with posttests at 1 and 10 minutes after 4 sets of unilateral Bulgarian squats to failure (1 minute rest between sets). Tests included a Y balance test (measures: distance reached by nondominant foot in anterior, posterior lateral, and posterior medial directions) and drop jump landing balance test from a 50-cm platform (measures: ground reaction force, electromyography, and center of pressure). The fatigue protocol induced 25.3% decrease in unilateral squat repetitions from set 1 to set 4. There were no significant condition main effects or interactions for any balance measure or EMG before or after fatigue. In conclusion, independent of fatigue, there was no significant effect of CS or KT on balance outcomes immediately and up to 10 minutes following the fatiguing intervention. Thus, nonfatigued or muscles weakened by fatigue did not benefit from CS and KT application. PMID:26705066

  3. An Invitro Comparative Evaluation of Compressive Strength and Antibacterial Activity of Conventional GIC and Hydroxyapatite Reinforced GIC in Different Storage Media

    PubMed Central

    Prabhakar, Attiguppe Ramasetty; Basappa, Nadig

    2015-01-01

    Background GIC is the most commonly used restorative material in pediatric dentistry since it has got various advantages like fluoride release, anticariogenic property and chemical adhesion to tooth but a major disadvantage is its contraindication in posterior teeth because of poor mechanical properties. Aim The purpose of this study is a modest attempt to explore the influence of the addition of 8% hydroxyapatite to conventional GIC on its compressive strength when immersed in different storage media and antibacterial activity. Materials and Methods One hundred and twenty six pellets of the specific dimension of 6 x 4 mm were prepared and divided into 6 groups and were immersed in deionized water, artificial saliva, lactic acid solution respectively for three hours everyday over 30 days test period. The compressive strength was measured by using a universal testing machine (AG-50kNG) at cross head of 1mm2/min and strength was determined after 1 day, 7 days, 30 days respectively and the antibacterial activity evaluated against Streptococcus mutans strain in brain heart infusion broth using serial dilution method. Statistical Analysis Group wise comparisons were made by one-way ANOVA followed by post-hoc Tukey’s test, Intergroup comparison was done with Mann-Whitney test. Results GIC±HAp showed significantly greater antibacterial activity against Streptococcus mutans when compared to GIC group. There was no statistically significant change in the compressive strength among the groups except for group 3 and group 6 when immersed in lactic acid had shown significant difference at the end of 24 hours. Conclusion The addition of 8% hydroxyapatite to GIC showed marked increased in the antibacterial activity of the conventional GIC against caries initiating organism without much increase in the compressive strength of the GIC when immersed in the different storage media. PMID:26393206

  4. Standardization Activities in TMF Test Methodologies

    NASA Technical Reports Server (NTRS)

    Verrilli, M. J.; Castelli, M. G.; Bressers, J.; Oehmke, R. L. T.

    1996-01-01

    No standard test practice currently exists for strain-controlled thermomechanical fatigue (TMF) testing. This paper discusses recent activities which lay the foundation for standardization of TMF test methods. Specifically, the paper documents the results of two interlaboratory TMF test programs, identifies key TMF symposia and workshops, and discusses efforts toward drafting a TMF standard test practice.

  5. Full-field strain measurement and fracture analysis of rat femora in compression test.

    PubMed

    Amin Yavari, Saber; van der Stok, Johan; Weinans, Harrie; Zadpoor, Amir Abbas

    2013-04-26

    There is a growing interest in studying the fracture behavior of bones, primarily due to the increasing societal burden of osteoporotic fractures. In addition, bone is one of the most important biological materials whose fracture behavior is not yet well understood. This is partly due to the fact that bone is a complex hierarchical material, and exhibits heterogeneous, anisotropic, and viscoelastic mechanical behavior. Understanding the fracture behavior of such a complex material requires application of a full-field strain measurement technique. Digital image correlation (DIC) is a relatively new full-field strain measurement technique that can be used for measurement of 3D surface strains during mechanical testing of different types of bones. In this study, we use the DIC technique to measure the surface strains during compression testing of two groups of rat femora. The first group of femora was harvested from young animals (12 weeks), while the second group was harvested from more mature animals (26 weeks). The surface strains are measured both in the linear range and close to the fracture. Using the measured data, we assess two strain-based fracture prediction criteria, namely equivalent strain fracture criterion and fracture limit diagram, to determine whether they can consistently predict the onset of fracture. The maximum load is measured to be 296±22 N (mean±SD) for young animals and 670±123 N for mature animals. It is shown that fracture in the vast majority of cases occurs in the area of maximum tensile strain. The equivalent strain fracture criterion predicts that the fracture occurs when the equivalent strain reaches 1.04±0.02% (average±SD) for young animals and 1.39±0.24% for mature animals. The fracture limit diagram predicts that the fracture occurs once the sum of major and minor principal surface strains reaches 0.63±0.23% for young animals and -0.63±0.30% for mature animals. Based on these numbers and consistency of the criteria with the

  6. A comparison of pressure compaction and diametral compression tests for determining granule strengths

    SciTech Connect

    Glass, S.J.; Newton, C.

    1994-12-31

    Lightning strikes can cause structural damage, ignite flammable materials, and produce circuit malfunctions in missiles, aircraft, and ground systems. Lightning arrestor connectors (LACs) are used to divert harmful lightning energy away from these systems by providing less destructive breakdown paths. Ceramic granules in the size range of 150--200 {micro}m are used in LACs to provide physical and electrical separation of contacts (pins) from the surrounding metal web, and to control the voltage breakdown level. Pressure compaction (P-C) tests were used to characterize the strength of ceramic granules. When compaction data are plotted as relative density of the compact versus the compaction pressure two linear regions are generally observed. The intersection of these regions, which is known as the ``breakpoint,`` has been used as a semi-quantitative measure of granule strength. Comparisons were made between the P-C breakpoint and strengths of 150--200 {micro}m diameter ZnO, TiO{sub 2} (rutile), and lead magnesium niobate-lead titanate (PMN-PT) granules, where the strengths were determined by diametral compression (D-C) tests. At high compaction pressures the compliance of the die itself is significant and was accounted for in the analyses. Tests were conducted at different compaction rates, and with different aspect ratio compacts. High aspect ratios and loading rates decrease the slope of the second linear portion of the compaction curve and produce higher apparent P-C breakpoints. Comparison of the P-C breakpoint to the average D-C strength indicates that the D-C strength is approximately fifty percent higher for PMN-PT granules. To eliminate the uncertainty in results due to irregular granules sizes and shapes, comparisons were made for uniform size (210 {micro}m) glass spheres. In this case the average D-C strength coincided with a second breakpoint in the P-C data, which occurred after compaction by a mechanism of bridge formation and collapse had ceased.

  7. Deformation twinning activated α --> ω transformation in titanium under shock compression

    NASA Astrophysics Data System (ADS)

    Zong, Hongxiang; Lookman, Turab

    Materials dynamics, especially the behavior of solids under extreme compression, is a topic of broad scientific and technological interest. However, less is known of the role of grain boundary structures on the shock response of hexagonal-close-packed metals. We use molecular dynamics simulations to study deformation mechanisms in shock compressed Ti bicrystals containing three types of grain boundary (GB) microstructures, i.e., coherent twin boundaries (CTBs), symmetric incoherent twin boundaries (ITB) and {1-210}asymmetric tilt grain boundaries. Our results show that both dislocation activity and the α -> ω phase transformation in Ti are sensitive to the GB characteristics. In particular, we find that the elastic shock wave can readily trigger the α -> ω transformation at CTBs but not at the other two GBs, and the activation of the α -> ω transformation at CTBs leads to considerable wave attenuation (i.e., the elastic precursor decay). Combined with first principle calculations, we find that CTBs can facilitate the overcoming of the energy barrier for the α -> ω transformation. Our findings have potential implications for interface engineering and materials design under extreme conditions.

  8. Hydromechanical Behaviour of Unconsolidated Granular Materials under Proportional Triaxial Compression Tests

    NASA Astrophysics Data System (ADS)

    Nguyen, V.; Gland, N. F.; Dautriat, J.; Guelard, J.; David, C.

    2010-12-01

    During the production of petroleum reservoirs, compaction due to depletion (pore fluid pressure reduction) can lead to emphasis of natural permeability anisotropy and significant permeability reduction. Under such effective stress increase, weakly consolidated reservoirs will undergo strong deformation inducing important modifications of the transport properties, which control the fluid flows in the reservoir and the productivity of the wells. Classically the mechanical loadings applied in the laboratory are either hydrostatic or deviatoric at constant confining pressure; however the 'in-situ' stress paths experienced by the reservoirs differ; it is thus important to perform loading tests with more appropriate conditions such as ‘proportional triaxial’ and ‘oedometric’. This study focuses on the elastoplatic behaviour of non to weakly consolidated reservoir rocks (analogues) and the influence of the stress path (K=ΔσH/ΔσV) on the evolutions of porosity and permeability. Generally, permeability of pourous rocks evolves in three stages: (1) initial decrease related to compaction (soft rocks) or closing of pre-existing microflaws (compact rocks), (2) small reduction associated to the 'linear' deformation regime, (3) drop due to a strong compaction linked to porosity collapse and grain crushing mechanisms. The intensity of this reduction depends on the stress path coefficient, the grain sharpness and the granular texture. We use a triaxial cell (maximum axial load of 80kN and maximum confinement of 69MPa) to perform proportional triaxial compression tests (0

  9. Microcrack evolution and brittle failure of Inada granite in triaxial compression tests at 140 MPa

    NASA Astrophysics Data System (ADS)

    Oda, M.; Katsube, T.; Takemura, T.

    2002-10-01

    A tensorial measure, called the crack tensor, is proposed to objectively define the crack geometry in crystalline rock as general as possible. Change of crack populations during brittle failure of rock (Inada granite) is analyzed in terms of the crack tensor and its invariants, which can be evaluated by a conventional petrographic analysis combined with stereology. A crack evolution law is formulated as a function of inelastic strain, so that we can easily depict how much damage accumulates in a sample loaded in a triaxial vessel by measuring the inelastic strain. When rock is loaded up to failure, the crack population satisfies a unique relation in the plot of the crack density versus the anisotropy, which are defined using the invariants of the crack tensors. It is suggested that failure of rock in uniaxial compression may be determined by a local condition such as a stress intensity factor at a crack tip. In the triaxial tests, on the other hand, rock fails when the crack density increases over a threshold value, which is a global condition depending on all cracks existing at failure. The threshold density is about 7 for the rock subjected to differential stress under confining pressures larger than 25 MPa. Under such a high crack density, the rock does not behave like a cracked solid, but rather like an assembly of rock blocks (granular material), and it starts to fail mainly due to the structurally induced instability, not due to the critical stress intensity factor at a crack tip. A throughgoing fault may develop as a result of the relative motion among the disintegrated blocks, sliding and rolling.

  10. Electrical conductivity of activated carbon-metal oxide nanocomposites under compression: a comparison study.

    PubMed

    Barroso-Bogeat, A; Alexandre-Franco, M; Fernández-González, C; Macías-García, A; Gómez-Serrano, V

    2014-12-01

    From a granular commercial activated carbon (AC) and six metal oxide (Al2O3, Fe2O3, SnO2, TiO2, WO3 and ZnO) precursors, two series of AC-metal oxide nanocomposites were prepared by wet impregnation, oven-drying at 120 °C, and subsequent heat treatment at 200 or 850 °C in an inert atmosphere. Here, the electrical conductivity of the resulting products was studied under moderate compression. The influence of the applied pressure, sample volume, mechanical work, and density of the hybrid materials was thoroughly investigated. The DC electrical conductivity of the compressed samples was measured at room temperature by the four-probe method. Compaction assays suggest that the mechanical properties of the nanocomposites are largely determined by the carbon matrix. Both the decrease in volume and the increase in density were relatively small and only significant at pressures lower than 100 kPa for AC and most nanocomposites. In contrast, the bulk electrical conductivity of the hybrid materials was strongly influenced by the intrinsic conductivity, mean crystallite size, content and chemical nature of the supported phases, which ultimately depend on the metal oxide precursor and heat treatment temperature. The supported nanoparticles may be considered to act as electrical switches either hindering or favouring the effective electron transport between the AC cores of neighbouring composite particles in contact under compression. Conductivity values as a rule were lower for the nanocomposites than for the raw AC, all of them falling in the range of semiconductor materials. With the increase in heat treatment temperature, the trend is toward the improvement of conductivity due to the increase in the crystallite size and, in some cases, to the formation of metals in the elemental state and even metal carbides. The patterns of variation of the electrical conductivity with pressure and mechanical work were slightly similar, thus suggesting the predominance of the pressure

  11. MRI-based inverse finite element approach for the mechanical assessment of patellar articular cartilage from static compression test.

    PubMed

    Knecht, Sven; Luechinger, Roger; Boesiger, Peter; Stüssi, Edgar

    2008-12-01

    The mechanical property of articular cartilage determines to a great extent the functionality of diarthrodial joints. Consequently, the early detection of mechanical and, thus, functional changes of cartilage is crucial for preventive measures to maintain the mobility and the quality of life of individuals. An alternative to conventional mechanical testing is the inverse finite element approach, enabling non-destructive testing of the tissue. We evaluated a method for the assessment of the equilibrium material properties of the patellar cartilage based on magnetic resonance imaging during patellofemoral compression. We performed ex vivo testing of two equine patellas with healthy cartilage, one with superficial defects, and one with synthetically degenerated cartilage to simulate a pre-osteoarthritic stage. Static compression with 400 N for 2 h resulted in morphological changes comparable to physiological in vivo deformations in humans. We observed a decrease of the equilibrium Young's modulus of the degenerated cartilage by -59%, which was in the range of the results from indentation (-74%) and confined compression tests (-58%). With the reported accuracy of magnetic resonance imaging and its reproducibility, the results indicate the potential to measure differences in Young's modulus with regard to cartilage degeneration and consequently to distinguish between healthy and pre-osteoarthritic cartilage. PMID:19037871

  12. Design and the parametric testing of the space station prototype integrated vapor compression distillation water recovery module

    NASA Technical Reports Server (NTRS)

    Reveley, W. F.; Nuccio, P. P.

    1975-01-01

    Potable water for the Space Station Prototype life support system is generated by the vapor compression technique of vacuum distillation. A description of a complete three-man modular vapor compression water renovation loop that was built and tested is presented; included are all of the pumps, tankage, chemical post-treatment, instrumentation, and controls necessary to make the loop representative of an automatic, self-monitoring, null gravity system. The design rationale is given and the evolved configuration is described. Presented next are the results of an extensive parametric test during which distilled water was generated from urine and urinal flush water with concentration of solids in the evaporating liquid increasing progressively to 60 percent. Water quality, quantity and production rate are shown together with measured energy consumption rate in terms of watt-hours per kilogram of distilled water produced.

  13. Extrasynaptic Glutamate Receptor Activation as Cellular Bases for Dynamic Range Compression in Pyramidal Neurons

    PubMed Central

    Oikonomou, Katerina D.; Short, Shaina M.; Rich, Matthew T.; Antic, Srdjan D.

    2012-01-01

    Repetitive synaptic stimulation overcomes the ability of astrocytic processes to clear glutamate from the extracellular space, allowing some dendritic segments to become submerged in a pool of glutamate, for a brief period of time. This dynamic arrangement activates extrasynaptic NMDA receptors located on dendritic shafts. We used voltage-sensitive and calcium-sensitive dyes to probe dendritic function in this glutamate-rich location. An excess of glutamate in the extrasynaptic space was achieved either by repetitive synaptic stimulation or by glutamate iontophoresis onto the dendrites of pyramidal neurons. Two successive activations of synaptic inputs produced a typical NMDA spike, whereas five successive synaptic inputs produced characteristic plateau potentials, reminiscent of cortical UP states. While NMDA spikes were coupled with brief calcium transients highly restricted to the glutamate input site, the dendritic plateau potentials were accompanied by calcium influx along the entire dendritic branch. Once initiated, the glutamate-mediated dendritic plateau potentials could not be interrupted by negative voltage pulses. Activation of extrasynaptic NMDA receptors in cellular compartments void of spines is sufficient to initiate and support plateau potentials. The only requirement for sustained depolarizing events is a surplus of free glutamate near a group of extrasynaptic receptors. Highly non-linear dendritic spikes (plateau potentials) are summed in a highly sublinear fashion at the soma, revealing the cellular bases of signal compression in cortical circuits. Extrasynaptic NMDA receptors provide pyramidal neurons with a function analogous to a dynamic range compression in audio engineering. They limit or reduce the volume of “loud sounds” (i.e., strong glutamatergic inputs) and amplify “quiet sounds” (i.e., glutamatergic inputs that barely cross the dendritic threshold for local spike initiation). Our data also explain why consecutive cortical UP

  14. 78 FR 33891 - Safety Advisory: Compressed Gas Cylinders That Have Not Been Tested Properly

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-06-05

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF TRANSPORTATION Pipeline and Hazardous Materials Safety Administration Safety Advisory: Compressed Gas Cylinders That Have... during normal transportation and use and may leak or rupture, resulting in property damage, injuries,...

  15. Hip adductor activations during run-to-cut manoeuvres in compression shorts: implications for return to sport after groin injury.

    PubMed

    Chaudhari, Ajit M W; Jamison, Steven T; McNally, Michael P; Pan, Xueliang; Schmitt, Laura C

    2014-01-01

    Athletes at high risk of groin strains in sports such as hockey and soccer often choose to wear shorts with directional compression to aid in prevention of or recovery from hip adductor strains. Large, eccentric contractions are known to result in or exacerbate strain injuries, but it is unknown if these shorts have a beneficial effect on hip adductor muscle activity. In this study, surface electromyography (EMG) of the adductor longus and ground reaction force (GRF) data were obtained simultaneously on 29 healthy individuals without previous history of serious injury while performing unanticipated 45° run-to-cut manoeuvres in a laboratory setting wearing shorts with non-directional compression (control, HeatGear, Under Armour, USA) or shorts with directional compression (directional, CoreShort PRO, Under Armour, USA), in random order. Average adductor activity in the stance leg was significantly lower in the directional condition than in the control condition during all parts of stance phase (all P < 0.042). From this preliminary analysis, wearing directional compression shorts appears to be associated with reduced stance limb hip adductor activity. Athletes seeking to reduce demand on the hip adductors as they approach full return to activities may benefit from the use of directional compression shorts. PMID:24669858

  16. Hip adductor activations during run-to-cut maneuvers in compression shorts: Implications for return to sport after groin injury

    PubMed Central

    CHAUDHARI, AJIT M. W.; JAMISON, STEVEN T.; MCNALLY, MICHAEL P.; PAN, XUELIANG; SCHMITT, LAURA C.

    2014-01-01

    Athletes at high risk of groin strains in sports such as hockey and soccer often choose to wear shorts with directional compression to aid in prevention or recovery from hip adductor strains. Large eccentric contractions are known to result in or exacerbate strain injuries, but it is unknown if these shorts have a beneficial effect on hip adductor muscle activity. In this study, surface electromyography of the adductor longus and ground reaction force (GRF) data were obtained simultaneously on 29 healthy individuals without previous history of serious injury while performing unanticipated 45° run-to-cut maneuvers in a laboratory setting wearing shorts with non-directional compression (control, HeatGear, Under Armour, USA) or shorts with directional compression (directional, CoreShort PRO, Under Armour, USA), in random order. Average adductor activity in the stance leg was significantly lower in the directional condition than in the control condition during all parts of stance phase (all p<0.042). From this preliminary analysis, wearing directional compression shorts appears to be associated with reduced stance limb hip adductor activity. Athletes seeking to reduce demand on the hip adductors as they approach full return to activities may benefit from the use of directional compression shorts. PMID:24669858

  17. Mechanical compression and nucleus pulposus application on dorsal root Ganglia differentially modify evoked neuronal activity in the thalamus.

    PubMed

    Nilsson, Elin; Brisby, Helena; Rask, Katarina; Hammar, Ingela

    2013-06-01

    A combination of mechanical compression caused by a protruding disc and leakage of nucleus pulposus (NP) from the disc core is presumed to contribute to intervertebral disc hernia-related pain. Experimental models of disc hernia including both components have resulted in changes in neuronal activity at the level of the dorsal root ganglion (DRG) and spinal cord, but changes within the brain have been less well studied. However, acute application of NP to a DRG without mechanical compression rapidly increases neuronal activity in the thalamus, a major brain relay nucleus processing information from sensory pathways including ascending nociceptive tracts. The combination of mechanical compression and NP might therefore result in further increases in central neuronal activity. Using an experimental disc herniation rat model including both mechanical compression and NP the present study aimed to investigate changes in neuronal activity in the contralateral thalamic ventral posterior lateral nucleus in vivo. Measurements were obtained while electrically stimulating the ipsilateral sciatic nerve at Aδ fiber intensities. The L4 DRG was subjected to light mechanical compression and NP exposure, and acute changes in evoked thalamic responses were recorded for up to 40 min. In order to compare effects in naïve animals with effects following a longer period of NP exposure, animals that were either disc-punctured or sham-operated 24 h previously were also included. In all animals, light mechanical compression of the DRG depressed the number of evoked neuronal responses. Prior NP exposure resulted in less potent changes following mechanical compression (80% of baseline) than that observed in naïve animals (50%). During the subsequent NP application, the number of evoked responses compared to baseline increased in pre-exposed animals (to 87%) as well as in naïve animals (72%) in which the removal of the mechanical compression resulted in a further increase (106%). The

  18. Experimental and Numerical Study on the Deformation Mechanism in AZ31B Mg Alloy Sheets Under Pulsed Electric-Assisted Tensile and Compressive Tests

    NASA Astrophysics Data System (ADS)

    Lee, Jinwoo; Kim, Se-Jong; Lee, Myoung-Gyu; Song, Jung Han; Choi, Seogou; Han, Heung Nam; Kim, Daeyong

    2016-06-01

    The uniaxial tensile and compressive stress-strain responses of AZ31B magnesium alloy sheet under pulsed electric current are reported. Tension and compression tests with pulsed electric current showed that flow stresses dropped instantaneously when the electric pulses were applied. Thermo-mechanical-electrical finite element analyses were also performed to investigate the effects of Joule heating and electro-plasticity on the flow responses of AZ31B sheets under electric-pulsed tension and compression tests. The proposed finite element simulations could reproduce the measured uniaxial tensile and compressive stress-strain curves under pulsed electric currents, when the temperature-dependent flow stress hardening model and thermal properties of AZ31B sheet were properly described in the simulations. In particular, the simulation results that fit best with experimental results showed that almost 100 pct of the electric current was subject to transform into Joule heating during electrically assisted tensile and compressive tests.

  19. Experimental and Numerical Study on the Deformation Mechanism in AZ31B Mg Alloy Sheets Under Pulsed Electric-Assisted Tensile and Compressive Tests

    NASA Astrophysics Data System (ADS)

    Lee, Jinwoo; Kim, Se-Jong; Lee, Myoung-Gyu; Song, Jung Han; Choi, Seogou; Han, Heung Nam; Kim, Daeyong

    2016-04-01

    The uniaxial tensile and compressive stress-strain responses of AZ31B magnesium alloy sheet under pulsed electric current are reported. Tension and compression tests with pulsed electric current showed that flow stresses dropped instantaneously when the electric pulses were applied. Thermo-mechanical-electrical finite element analyses were also performed to investigate the effects of Joule heating and electro-plasticity on the flow responses of AZ31B sheets under electric-pulsed tension and compression tests. The proposed finite element simulations could reproduce the measured uniaxial tensile and compressive stress-strain curves under pulsed electric currents, when the temperature-dependent flow stress hardening model and thermal properties of AZ31B sheet were properly described in the simulations. In particular, the simulation results that fit best with experimental results showed that almost 100 pct of the electric current was subject to transform into Joule heating during electrically assisted tensile and compressive tests.

  20. Compressibility and uncoupling of cytochrome P450cam: high pressure FTIR and activity studies.

    PubMed

    Jung, Christiane; Kozin, Sergey A; Canny, Bernard; Chervin, Jean-Claude; Hoa, Gaston Hui Bon

    2003-12-01

    The effect of the hydrostatic pressure on the CO ligand stretch vibration in cytochrome P450cam-CO bound with various substrates is studied by FTIR. The vibration frequency is linearily shifted to lower values with increasing pressure. The slope of the shift gives the isothermal compressibility of the heme pocket and is found to be related to the high-spin state content in an opposite direction to that previously observed from the pressure-induced shift of the Soret band. This opposite behaviour is explained by the dual effect of heme pocket water molecules both on the CO ligand and on electrostatic potentials produced by the protein at the distal side. The latter effect disturbs ligand-distal side contacts which are needed for a specific proton transfer in oxygen activation when dioxygen is the ligand. Their loss results in uncoupled H(2)O(2) formation. PMID:14630042

  1. Experimental validation of a flat punch indentation methodology calibrated against unconfined compression tests for determination of soft tissue biomechanics.

    PubMed

    Delaine-Smith, R M; Burney, S; Balkwill, F R; Knight, M M

    2016-07-01

    Mechanical characterisation of soft biological tissues using standard compression or tensile testing presents a significant challenge due to specimen geometrical irregularities, difficulties in cutting intact and appropriately sized test samples, and issues with slippage or damage at the grips. Indentation can overcome these problems but requires fitting a model to the resulting load-displacement data in order to calculate moduli. Despite the widespread use of this technique, few studies experimentally validate their chosen model or compensate for boundary effects. In this study, viscoelastic hydrogels of different concentrations and dimensions were used to calibrate an indentation technique performed at large specimen-strain deformation (20%) and analysed with a range of routinely used mathematical models. A rigid, flat-ended cylindrical indenter was applied to each specimen from which 'indentation moduli' and relaxation properties were calculated and compared against values obtained from unconfined compression. Only one indentation model showed good agreement (<10% difference) with all moduli values obtained from compression. A sample thickness to indenter diameter ratio ≥1:1 and sample diameter to indenter diameter ratio ≥4:1 was necessary to achieve the greatest accuracy. However, it is not always possible to use biological samples within these limits, therefore we developed a series of correction factors. The approach was validated using human diseased omentum and bovine articular cartilage resulting in mechanical properties closely matching compression values. We therefore present a widely useable indentation analysis method to allow more accurate calculation of material mechanics which is important in the study of soft tissue development, ageing, health and disease. PMID:26974584

  2. An image compression survey and algorithm switching based on scene activity

    NASA Technical Reports Server (NTRS)

    Hart, M. M.

    1985-01-01

    Data compression techniques are presented. A description of these techniques is provided along with a performance evaluation. The complexity of the hardware resulting from their implementation is also addressed. The compression effect on channel distortion and the applicability of these algorithms to real-time processing are presented. Also included is a proposed new direction for an adaptive compression technique for real-time processing.

  3. Dynamic Compression Effects on Immature Nucleus Pulposus: a Study Using a Novel Intelligent and Mechanically Active Bioreactor

    PubMed Central

    Li, Pei; Gan, Yibo; Wang, Haoming; Zhang, Chengmin; Wang, Liyuan; Xu, Yuan; Song, Lei; Li, Songtao; Li, Sukai; Ou, Yangbin; Zhou, Qiang

    2016-01-01

    Background: Previous cell culture and animal in vivo studies indicate the obvious effects of mechanical compression on disc cell biology. However, the effects of dynamic compression magnitude, frequency and duration on the immature nucleus pulposus (NP) from an organ-cultured disc are not well understood. Objective: To investigate the effects of a relatively wide range of compressive magnitudes, frequencies and durations on cell apoptosis and matrix composition within the immature NP using an intelligent and mechanically active bioreactor. Methods: Discs from the immature porcine were cultured in a mechanically active bioreactor for 7 days. The discs in various compressive magnitude groups (0.1, 0.2, 0.4, 0.8 and 1.3 MPa at a frequency of 1.0 Hz for 2 hours), frequency groups (0.1, 0.5, 1.0, 3.0 and 5.0 Hz at a magnitude of 0.4 MPa for 2 hours) and duration groups (1, 2, 4 and 8 hours at a magnitude of 0.4 MPa and frequency of 1.0 Hz) experienced dynamic compression once per day. Discs cultured without compression were used as controls. Immature NP samples were analyzed using the TUNEL assay, histological staining, glycosaminoglycan (GAG) content measurement, real-time PCR and collagen II immunohistochemical staining. Results: In the 1.3 MPa, 5.0 Hz and 8 hour groups, the immature NP showed a significantly increase in apoptotic cells, a catabolic gene expression profile with down-regulated matrix molecules and up-regulated matrix degradation enzymes, and decreased GAG content and collagen II deposition. In the other compressive magnitude, frequency and duration groups, the immature NP showed a healthier status regarding NP cell apoptosis, gene expression profile and matrix production. Conclusion: Cell apoptosis and matrix composition within the immature NP were compressive magnitude-, frequency- and duration-dependent. The relatively high compressive magnitude or frequency and long compressive duration are not helpful for maintaining the healthy status of an

  4. The Development of the Electrically Controlled High Power RF Switch and Its Application to Active RF Pulse Compression Systems

    SciTech Connect

    Guo, Jiquan

    2008-12-01

    In the past decades, there has been increasing interest in pulsed high power RF sources for building high-gradient high-energy particle accelerators. Passive RF pulse compression systems have been used in many applications to match the available RF sources to the loads requiring higher RF power but a shorter pulse. Theoretically, an active RF pulse compression system has the advantage of higher efficiency and compactness over the passive system. However, the key component for such a system an element capable of switching hundreds of megawatts of RF power in a short time compared to the compressed pulse width is still an open problem. In this dissertation, we present a switch module composed of an active window based on the bulk effects in semiconductor, a circular waveguide three-port network and a movable short plane, with the capability to adjust the S-parameters before and after switching. The RF properties of the switch module were analyzed. We give the scaling laws of the multiple-element switch systems, which allow the expansion of the system to a higher power level. We present a novel overmoded design for the circular waveguide three-port network and the associated circular-to-rectangular mode-converter. We also detail the design and synthesis process of this novel mode-converter. We demonstrate an electrically controlled ultra-fast high power X-band RF active window built with PIN diodes on high resistivity silicon. The window is capable of handling multi-megawatt RF power and can switch in 2-300ns with a 1000A current driver. A low power active pulse compression experiment was carried out with the switch module and a 375ns resonant delay line, obtaining 8 times compression gain with a compression ratio of 20.

  5. Design and testing of z-shaped stringer-stiffened compression panels -- Evaluation of ARALL, GLARE, AND 2090 materials

    SciTech Connect

    Wu, M.; Reddy, S.V.; Wilson, D.

    1997-12-31

    Within the aerospace industry, there is a constant objective to develop more efficient and more economical aircraft. It is well known that the more prohibitive costs of air travel are associated with fuel consumption and the service losses incurred during downtime maintenance. Obviously, fuel consumption is greatly affected by weight. Thus, there is a search for new materials and construction techniques that offer substantial weight savings. A design study was conducted to determine the potential weight savings and performance increase from advanced metallic materials for wing skin panels. The materials included aluminum lithium 2090-T83, ARALL-3 (aramid-reinforced aluminum laminate) and GLARE-2 (glass-aluminium-reinforced epoxy). This wing has mechanically attached stringers to stiffen the panel against compressive and shear loading. The advanced skin materials were designed into an advanced wing box; advantage was taken of the increase in strength and stiffness. Two 2090-T83 aluminum-lithium skins with 7075-T6511 extruded Z-shaped stringers bonded to them were used for the evaluation of the upper wing cover structure. One panel had five bays, the other four. The study confirmed that a weight savings in the order of 10 to 15% can be achieved with panels made with these advanced materials. The compression tests showed that all test panels failed in column bending and the predicted critical loads compared to those from the tests were conservative. The tests also validated the design methodology.

  6. Investigation of the Rod Compression Test and Simulation Study of 6061 Aluminum Alloy in the Semisolid State

    NASA Astrophysics Data System (ADS)

    Aboutalebian, Gholam Hossein; Mosaddegh, Peiman; Moradi, Mehran

    2014-06-01

    Processing material in the semisolid state has the advantage of a low energy requirement in comparison to processing in the solid state. In this study, a simple rod compression test of AL6061 alloy in the semisolid state is experimentally investigated with solid volume fractions of 0.6, 0.7, 0.8, and 0.9 and various ram speeds of 2, 5, and 7 mm/min. Also, commercial Deform-3D finite-element software is used to model the forging process of a cylindrical rod. In all simulations, the material model in macroscopic behavior with various solid volume fractions is considered as viscoplastic when its liquid volume fraction is ignored. The Sellars and Tegart constitutive model is used to determine the material behavior in this state. The experimental and simulation results show that the compression force increases with an increase in both the solid volume fraction and ram speed. By analyzing the results of compression force, it can be claimed that the maximum difference between ram speeds of 2 and 7 mm/min at 862 K (589 °C) is around 27 pct, while the maximum difference between 862 and 883 K (589 °C and 610 °C) at a minimum ram speed of 2 mm/min is around 15 pct. So the strain rate of deformation has a greater effect than temperature in semisolid deformation.

  7. Dynamic impact testing on post-tensioned steel rectangular hollow sections; An investigation into the "compression-softening" effect

    NASA Astrophysics Data System (ADS)

    Noble, Darragh; Nogal, Maria; O`Connor, Alan; Pakrashi, Vikram

    2015-10-01

    This paper describes the results of dynamic impact testing on externally axially loaded steel rectangular hollow sections (RHSs) and compares the response to that of externally post-tensioned steel RHSs. Both the fundamental natural bending frequency of the beam sections and the corresponding damping ratios have been calculated from the measured dynamic response of the beam to a series of impact hammer strikes. The validity of the "compression-softening" effect for post-tensioned sections is tested. The implications of the research are vast, as currently, there is significant disagreement among researchers about the effect of pre- and post-tensioning loads on the dynamic characteristics of structures. The fundamental bending frequencies have been calculated and corresponding damping ratio have been calculated from dynamic test results for each axial load level. The bending frequencies have been calculated repeatedly while changing the axial load level and the subsequent changes in both frequency and damping ratio, with increasing axial load level have been analysed to determine if the results are statistically significant. It has been determined that "compression softening" theory is not valid for pre- or post-tensioned sections.

  8. Effects of coating thickness and interfacial roughness on cracking and delamination strength of WC-Co coating measured by ring compression test

    NASA Astrophysics Data System (ADS)

    Kato, Masahiko; Nazul, Mahmoud; Itti, Takeshi; Akebono, Hiroyuki; Sugeta, Atsushi; Mitani, Eiji

    2014-08-01

    The effects of coating thickness and interfacial roughness on the interfacial fracture toughness of tungsten carbide-cobalt (WC-Co) coatings were evaluated using a ring compression test. WC-Co powder was sprayed on steel (JIS:SS400) rings by a high-velocity air- fuel method in coatings with various thicknesses and values of interfacial roughness. The ring compression test was carried out, and the cracking and delamination behavior of the coatings was observed using charge-coupled-device cameras. The results showed that cracking perpendicular to the loading direction occurred in the coatings during the ring compression test, and the cracking strength obtained from the ring compression test decreased slightly with increasing coating thickness, but was independent of the interfacial roughness. Upon further increase of the compression load, the coatings delaminated from the substrate. The interfacial fracture toughness calculated from the delamination of the coatings during the ring compression test decreased with increasing coating thickness and increased with increasing interfacial roughness.

  9. Active measurements of defect processes in shock compressed metals and other solids

    SciTech Connect

    Graham, R.A.

    1980-01-01

    Solid samples have been routinely recovered for examination after having been subjected to high pressure shock loading. Such investigations have revealed many unique and interesting defect features and are essential if a detailed understanding of shock deformation processes is to be achieved. Nevertheless, examination of samples hours or days after they are compressed for only a few microseconds in a loading whose rise time may be subnanosecond fails to address the relationship between the residual defect structure and that existing during the loading. Electrical probes, and to a lesser extent optical probes, have provided reasonably direct measurements of defect states and some limited information on the evolution of these states. For example, measurements of the electrical resistance of metals provide an indication of vacancy concentrations. Similarly, measurements of shock-induced electrical polarization in insulating solids have provided evidence that large numbers of point defects are generated and displaced by the stress and velocity gradients within the shock fronts. Optical measurements of shock-induced bleaching of color centers in NaCl have provided some evidence for kinetics of the formation of higher-order point defects. This paper reviews the status of active measurements which have provided information about shock-induced changes in the defect state of solids.

  10. Application of faceted yield surfaces for simulating compression tests of textured materials

    SciTech Connect

    Maudlin, P.J.; Wright, S.I.; Gray, G.T. III; House, J.W.

    1995-09-01

    Constitutive modeling used for most forming calculations assume an isotropic yield function with isotropic hardening. This assumption usually takes the form of an isotropic elastic stiffness tensor, a realistic flow stress model and a von Mises yield function. Real materials deviate from isotropy both in elasticity and plasticity. The calculations described here relax the assumptions of isotropic elasticity and plasticity by utilizing direct measurements of the elastic stiffness tensor and anisotropic representations of yield surfaces, in particular surfaces tessellated from direct measurements of material texture. This effort validates the use of such constitutive modeling by simulating quasi-static, uniaxial stress compression and Taylor Cylinder impact, and comparing their cross-sectional ``footprints`` to experimental data.

  11. Longitudinal compressive failure modes in fiber composites End attachment effects on IITRI type test specimens

    NASA Technical Reports Server (NTRS)

    Chamis, C. C.; Sinclair, J. H.

    1985-01-01

    The end-attachment effects on longitudinal compressive strength of IITRI type specimen unidirectional fiber composites are formally assessed using finite-element analysis (FEA) in conjunction with composite mechanics. Sixteen different cases were analyzed to evaluate end-attachment effects (such as degree of misalignment, type of misalignment, progressive end-tab debonding, and specimen thickness) on stress distribution, peak stresses, buckling loads, and buckling mode shapes. The results obtained from the FEA and comparisons with fractured specimens show that eccentricities induce bending-type stresses which peak near the end-tabs and cause flexural type fracture. Also, guidelines are included for placing back-to-back strain gages to measure the presence/absence of possible end-attachment and eccentricity effects.

  12. Compressed gas manifold

    DOEpatents

    Hildebrand, Richard J.; Wozniak, John J.

    2001-01-01

    A compressed gas storage cell interconnecting manifold including a thermally activated pressure relief device, a manual safety shut-off valve, and a port for connecting the compressed gas storage cells to a motor vehicle power source and to a refueling adapter. The manifold is mechanically and pneumatically connected to a compressed gas storage cell by a bolt including a gas passage therein.

  13. Application of wavelet filtering and Barker-coded pulse compression hybrid method to air-coupled ultrasonic testing

    NASA Astrophysics Data System (ADS)

    Zhou, Zhenggan; Ma, Baoquan; Jiang, Jingtao; Yu, Guang; Liu, Kui; Zhang, Dongmei; Liu, Weiping

    2014-10-01

    Air-coupled ultrasonic testing (ACUT) technique has been viewed as a viable solution in defect detection of advanced composites used in aerospace and aviation industries. However, the giant mismatch of acoustic impedance in air-solid interface makes the transmission efficiency of ultrasound low, and leads to poor signal-to-noise (SNR) ratio of received signal. The utilisation of signal-processing techniques in non-destructive testing is highly appreciated. This paper presents a wavelet filtering and phase-coded pulse compression hybrid method to improve the SNR and output power of received signal. The wavelet transform is utilised to filter insignificant components from noisy ultrasonic signal, and pulse compression process is used to improve the power of correlated signal based on cross-correction algorithm. For the purpose of reasonable parameter selection, different families of wavelets (Daubechies, Symlet and Coiflet) and decomposition level in discrete wavelet transform are analysed, different Barker codes (5-13 bits) are also analysed to acquire higher main-to-side lobe ratio. The performance of the hybrid method was verified in a honeycomb composite sample. Experimental results demonstrated that the proposed method is very efficient in improving the SNR and signal strength. The applicability of the proposed method seems to be a very promising tool to evaluate the integrity of high ultrasound attenuation composite materials using the ACUT.

  14. Dynamic High-temperature Testing of an Iridium Alloy in Compression at High-strain Rates: Dynamic High-temperature Testing

    SciTech Connect

    Song, B.; Nelson, K.; Lipinski, R.; Bignell, J.; Ulrich, G.; George, E. P.

    2014-08-21

    Iridium alloys have superior strength and ductility at elevated temperatures, making them useful as structural materials for certain high-temperature applications. However, experimental data on their high-strain -rate performance are needed for understanding high-speed impacts in severe environments. Kolsky bars (also called split Hopkinson bars) have been extensively employed for high-strain -rate characterization of materials at room temperature, but it has been challenging to adapt them for the measurement of dynamic properties at high temperatures. In our study, we analyzed the difficulties encountered in high-temperature Kolsky bar testing of thin iridium alloy specimens in compression. We made appropriate modifications using the current high-temperature Kolsky bar technique in order to obtain reliable compressive stress–strain response of an iridium alloy at high-strain rates (300–10 000 s-1) and temperatures (750 and 1030°C). The compressive stress–strain response of the iridium alloy showed significant sensitivity to both strain rate and temperature.

  15. Dynamic High-temperature Testing of an Iridium Alloy in Compression at High-strain Rates: Dynamic High-temperature Testing

    DOE PAGESBeta

    Song, B.; Nelson, K.; Lipinski, R.; Bignell, J.; Ulrich, G.; George, E. P.

    2014-08-21

    Iridium alloys have superior strength and ductility at elevated temperatures, making them useful as structural materials for certain high-temperature applications. However, experimental data on their high-strain -rate performance are needed for understanding high-speed impacts in severe environments. Kolsky bars (also called split Hopkinson bars) have been extensively employed for high-strain -rate characterization of materials at room temperature, but it has been challenging to adapt them for the measurement of dynamic properties at high temperatures. In our study, we analyzed the difficulties encountered in high-temperature Kolsky bar testing of thin iridium alloy specimens in compression. We made appropriate modifications using themore » current high-temperature Kolsky bar technique in order to obtain reliable compressive stress–strain response of an iridium alloy at high-strain rates (300–10 000 s-1) and temperatures (750 and 1030°C). The compressive stress–strain response of the iridium alloy showed significant sensitivity to both strain rate and temperature.« less

  16. Compressed Genotyping

    PubMed Central

    Erlich, Yaniv; Gordon, Assaf; Brand, Michael; Hannon, Gregory J.; Mitra, Partha P.

    2011-01-01

    Over the past three decades we have steadily increased our knowledge on the genetic basis of many severe disorders. Nevertheless, there are still great challenges in applying this knowledge routinely in the clinic, mainly due to the relatively tedious and expensive process of genotyping. Since the genetic variations that underlie the disorders are relatively rare in the population, they can be thought of as a sparse signal. Using methods and ideas from compressed sensing and group testing, we have developed a cost-effective genotyping protocol to detect carriers for severe genetic disorders. In particular, we have adapted our scheme to a recently developed class of high throughput DNA sequencing technologies. The mathematical framework presented here has some important distinctions from the ’traditional’ compressed sensing and group testing frameworks in order to address biological and technical constraints of our setting. PMID:21451737

  17. A computer program for plotting stress-strain data from compression, tension, and torsion tests of materials

    NASA Technical Reports Server (NTRS)

    Greenbaum, A.; Baker, D. J.; Davis, J. G., Jr.

    1974-01-01

    A computer program for plotting stress-strain curves obtained from compression and tension tests on rectangular (flat) specimens and circular-cross-section specimens (rods and tubes) and both stress-strain and torque-twist curves obtained from torsion tests on tubes is presented in detail. The program is written in FORTRAN 4 language for the Control Data 6000 series digital computer with the SCOPE 3.0 operating system and requires approximately 110000 octal locations of core storage. The program has the capability of plotting individual strain-gage outputs and/or the average output of several strain gages and the capability of computing the slope of a straight line which provides a least-squares fit to a specified section of the plotted curve. In addition, the program can compute the slope of the stress-strain curve at any point along the curve. The computer program input and output for three sample problems are presented.

  18. Anti-buckling fatigue test assembly. [for subjecting metal specimen to tensile and compressive loads at constant temperature

    NASA Technical Reports Server (NTRS)

    Eichenbrenner, F. F.; Imig, L. A. (Inventor)

    1974-01-01

    An antibuckling fatigue test assembly is described for holding a metal specimen which is subjected to compression and to rapid cyclical heating and cooling while permitting visual observation. In an illustrative embodiment of this invention, the anti-buckling fatigue test apparatus includes first and second guide members between which the metal specimen is disposed and held, a heating assembly comprising a suitable heating source such as a quartz lamp and a reflecting assembly directing the heat onto the specimen, and a cooling assembly for directing a suitable cooling fluid such as air onto the specimen. The guide members each have a passage to permit the heat to be directed onto the specimen. An opening is provided in the reflecting assembly to permit visual inspection of that region of the specimen adjacent to the opening onto which the heat is directed.

  19. High Temperature Expansion Due to Compression Test for the Determination of a Cladding Material Failure Criterion under RIA Loading Conditions

    SciTech Connect

    Le Saux, M.; Poussard, C.; Averty, X.; Sainte Catherine, C.; Carassou, S.

    2007-07-01

    This paper is mainly dedicated to the development of an out-of-pile test reproducing the thermo-mechanical loading conditions encountered during the first stage of a Reactivity Initiated Accidents (RIA) transient, dominated by Pellet Clad Mechanical Interaction (PCMI). In particular, the strain-controlled clad loading under high strain rate associated with temperatures up to 600 deg. C expected during the PCMI phase is simulated by an Expansion Due to Compression (EDC) test achievable at high temperature. The use of appropriate materials for the inner pellet made it possible to achieve the tests from 20 deg. C up to 900 deg. C. The interpretation of the test data is supported by Finite Element Analysis (FEA) including parameters tuned using an inverse method coupling FEA and tests results. A deformation model, identified upon the PROMETRA (Transient Mechanical Properties) experimental database and describing the anisotropic viscoplastic behavior of Cold-Worked Stress Relieved Zircaloy-4 cladding alloys under typical RIA loading conditions, is exploited. The combined analysis of experimental results and finite element simulations provides a deeper understanding of the deformation mode (near pure hoop tension) that arises during the tests. The failure mode appears to be representative of that obtained on tubes during the PCMI stage of RIA experiments. An appropriate device is currently developed in order to reach a bi-axiality of the loading path closer to that expected during the PCMI stage (between plane-strain and equal-biaxial tension). (authors)

  20. Effect of internal heating during hot compression testing on the stress-strain behavior and hot working characteristics of Alloy 304L

    SciTech Connect

    Mataya, M.C.; Sackschewsky, V.E.

    1993-05-01

    Temperature change from conversion of deformation to internal heat, and its effect on stress-strain behavior of alloy 304L was investigated by initially isothermal (temperature of specimen, compression dies, environment equilibrated at initiation of test) uniaxial compression. Strain rate was varied 0.01 s{sup {minus}1} to 1 s{sup {minus}1} (thermal state of specimen varied from nearly isothermal to nearly adiabatic). Specimens were deformed at 750 to 1150 to a strain of 1. Change in temperature with strain was calculated via finite element analysis from measured stress-strain data and predictions were confirmed with thermocouples to verify the model. Temperature increased nearly linearly at the highest strain rate, consistent with temperature rise being a linear function of strain (adiabatic). As strain rate was lowered, heat transfer from superheated specimen to cooler dies caused sample temperature to increase and then decrease with strain as the sample thinned and specimen-die contact area increased. As-measured stress was corrected. Resulting isothermal flow curves were compared to predictions of a simplified method suggested by Thomas and Shrinivasan and differences are discussed. Strain rate sensitivity, activation energy for deformation, and flow curve peak associated with onset of dynamic recrystallization were determined from both as-measured and isothermal stress-strain data and found to vary widely. The impact of utilizing as-measured stress-strain data, not corrected for internal heating, on results of a number of published investigations is discussed.

  1. Geothermal reservoir characterization through active thermal testing

    NASA Astrophysics Data System (ADS)

    Jung, Martin; Klepikova, Maria; Jalali, Mohammadreza; Fisch, Hansruedi; Loew, Simon; Amann, Florian

    2016-04-01

    Development and deployment of Enhanced Geothermal Systems (EGS) as renewable energy resources are part of the Swiss Energy Strategy 2050. To pioneer further EGS projects in Switzerland, a decameter-scale in-situ hydraulic stimulation and circulation (ISC) experiment has been launched at the Grimsel Test Site (GTS). The experiments are hosted in a low fracture density volume of the Grimsel granodiorite, similar to those expected at the potential enhanced geothermal system sites in the deep basement rocks of Northern Switzerland. One of the key goals of this multi-disciplinary experiment is to provide a pre- and post-stimulation characterization of the hydraulic and thermal properties of the stimulated fracture network with high resolution and to determine natural structures controlling the fluid flow and heat transport. Active thermal tests including thermal dilution tests and heat tracer tests allow for investigation of groundwater fluid flow and heat transport. Moreover, the spatial and temporal integrity of distributed temperature sensing (DTS) monitoring upgrades the potential and applicability of thermal tests in boreholes (e.g. Read et al., 2013). Here, we present active thermal test results and discuss the advantages and limitations of this method compared to classical approaches (hydraulic packer tests, solute tracer tests, flowing fluid electrical conductivity logging). The experimental tests were conducted in two boreholes intersected by a few low to moderately transmissive fault zones (fracture transmissivity of about 1E-9 m2/s - 1E-7 m2/s). Our preliminary results show that even in low-permeable environments active thermal testing may provide valuable insights into groundwater and heat transport pathways. Read T., O. Bour, V. Bense, T. Le Borgne, P. Goderniaux, M.V. Klepikova, R. Hochreutener, N. Lavenant, and V. Boschero (2013), Characterizing groundwater flow and heat transport in fractured rock using Fiber-Optic Distributed Temperature Sensing

  2. Normalization of Impact Energy by Laminate Thickness for Compression After Impact Testing

    NASA Technical Reports Server (NTRS)

    Nettles, A. T.; Hromisin, S. M.

    2013-01-01

    The amount of impact energy used to damage a composite laminate is a critical parameter when assessing residual strength properties. The compression after impact (CAI) strength of impacted laminates is dependent upon how thick the laminate is and this has traditionally been accounted for by normalizing (dividing) the impact energy by the laminate's thickness. However, when comparing CAI strength values for a given lay-up sequence and fiber/resin system, dividing the impact energy by the specimen thickness has been noted by the author to give higher CAI strength values for thicker laminates. A study was thus undertaken to assess the comparability of CAI strength data by normalizing the impact energy by the specimen thickness raised to a power to account for the higher strength of thicker laminates. One set of data from the literature and two generated in this study were analyzed by dividing the impact energy by the specimen thickness to the 1, 1.5, 2, and 2.5 powers. Results show that as laminate thickness and damage severity decreased, the value which the laminate thickness needs to be raised to in order to yield more comparable CAI data increases.

  3. Performance tests of a single-cylinder compression-ignition engine with a displacer piston

    NASA Technical Reports Server (NTRS)

    Moore, C S; Foster, H H

    1935-01-01

    Engine performance was investigated using a rectangular displacer on the piston crown to cause a forced air flow in a vertical-disk combustion chamber of a single-cylinder, 4-stroke-cycle compression-ignition engine. The optimum air-flow area was determined first with the area concentrated at one end of the displacer and then with the area equally divided between two passages, one at each end of the displacer. Best performance was obtained with the two-passage air flow arranged to give a calculated maximum air-flow speed of 8 times the linear crank-pin speed. With the same fuel-spray formation as used without the air flow, the maximum clear exhaust brake mean effective pressure at 1,500 r.p.m. was increased from 90 to 115 pounds per square inch and the corresponding fuel consumption reduced from 0.46 to 0.43 pound per brake horsepower-hour. At 1,200 r.p.m., a maximum clear exhaust brake mean effective pressure of 120 pounds per square inch was obtained at a fuel consumption of 0.42 pound per brake horsepower-hour. At higher specific fuel consumption the brake mean effective pressure was still increasing rapidly.

  4. EBSD analysis of (10–12) twinning activity in Mg–3Al–1Zn alloy during compression

    SciTech Connect

    Wang, Bingshu; Deng, Liping; Guo, Ning; Xu, Zeren; Li, Qiang

    2014-12-15

    The (10–12) twinning activity of Mg–3Al–1Zn magnesium alloy during uniaxial compression at room temperature has been investigated by electron backscatter diffraction. The results indicated that the twinning activity was closely related with two angles: one was the angle between the c-axis and the compression direction and the other was the angle between the a-axis and the titling direction in the basal plane for a given relation between the c-axis and the compression direction. These two parameters can be used to explain which twinning variant will operate under the given strain path. For the grains containing a single (10–12) twinning variant, the (10–12) twinning variant occurred in a wide range of Schmid factor values (0 < Schmid factor < 0.5) and the Schmid factor rank of 1 or 2 was the most commonly observed. By contrast, for the grains containing two (10–12) twinning variants, the (10–12) twinning activity exhibited a stronger orientation dependence and the combinations of Schmid factor ranks 1–3 and 1–2 were the most commonly observed. - Highlights: • Twinning activity of AZ31 magnesium alloy was investigated by EBSD. • (10–12) twinning shows a strong orientation dependence. • Two angles can be used to explain which twin variant will operate.

  5. Statistics of active and passive scalars in one-dimensional compressible turbulence.

    PubMed

    Ni, Qionglin; Chen, Shiyi

    2012-12-01

    Statistics of the active temperature and passive concentration advected by the one-dimensional stationary compressible turbulence at Re_{λ}=2.56×10^{6} and M_{t}=1.0 is investigated by using direct numerical simulation with all-scale forcing. It is observed that the signal of velocity, as well as the two scalars, is full of small-scale sawtooth structures. The temperature spectrum corresponds to G(k)∝k^{-5/3}, whereas the concentration spectrum acts as a double power law of H(k)∝k^{-5/3} and H(k)∝k^{-7/3}. The probability distribution functions (PDFs) for the two scalar increments show that both δT and δC are strongly intermittent at small separation distance r and gradually approach the Gaussian distribution as r increases. Simultaneously, the exponent values of the PDF tails for the large negative scalar gradients are q_{θ}=-4.0 and q_{ζ}=-3.0, respectively. A single power-law region of finite width is identified in the structure function (SF) of δT; however, in the SF of δC, there are two regions with the exponents taken as a local minimum and a local maximum. As for the scalings of the two SFs, they are close to the Burgers and Obukhov-Corrsin scalings, respectively. Moreover, the negative filtered flux at large scales and the time-increasing total variance give evidences to the existence of an inverse cascade of the passive concentration, which is induced by the implosive collapse in the Lagrangian trajectories. PMID:23368038

  6. Strength Anisotropy of Berea Sandstone: Results of X-Ray Computed Tomography, Compression Tests, and Discrete Modeling

    NASA Astrophysics Data System (ADS)

    Kim, Kwang Yeom; Zhuang, Li; Yang, Hwayoung; Kim, Hanna; Min, Ki-Bok

    2016-04-01

    Berea sandstone in northern Ohio is a transversely isotropic rock. X-ray CT investigations showed that its internal structure is composed of cross-bedded loose layers and relatively thin tightly packed layers called bedding. Uniaxial compression tests were performed on different Berea sandstone specimens. The uniaxial compressive strength (UCS) decreases with increasing porosity, and also decreases with increasing inclination of the bedding plane relative to horizontal line. Two-dimensional discrete modeling was applied to investigate the micromechanical behavior of Berea sandstone. Different microparameters were assigned to loose and tight layers. The UCS simulation results agree well with the experimental results. At the peak stress, cracks almost always develop in loose layers regardless of the bedding plane orientation. In addition, both normal and shear cracks occur earlier for specimens with a higher inclination angle. No correlations were found between the inclination angle of failure planes and the orientation of bedding planes. The bedding planes of Berea sandstone are not weak planes. The strength anisotropy of Berea sandstone is not significant compared with other rocks such as shale, gneiss, and schist.

  7. Monitoring of the manufacturing process for ambroxol hydrochloride tablet using NIR-chemometric methods: compression effect on content uniformity model and relevant process parameters testing.

    PubMed

    Yang, Hongqin; Liao, Xiaoxiang; Peng, Feng; Wang, Wan; Liu, Yanxin; Yan, Jin; Li, Hui

    2015-01-01

    This study aimed at using near-infrared (NIR) spectroscopy to monitor compaction pressure for simultaneously determining the tensile strength and content uniformity, as well as moisture and mean particle size of ambroxol hydrochloride tablets. The content uniformity, compression force and tensile strength of the laboratory samples were obtained by pressing a mixture of active principle and excipient components into tablets. To reduce the spectral baseline shift of the laboratory samples, the compaction pressure applied to the mixture was assessed by a variable pressure test. Production samples were added to the test and subjected to principal component analysis. The expanded partial least-squares (PLS) calibration model used to quantify the active content was more accurate than the model constructed from laboratory samples using the production tablets included in the calibration set. The model showed good predictability, with correlation coefficient (R) 0.9977. The validation and reliability of the content model were evaluated to determine trueness and reliability for the measurement of individual production tablets and the laboratory tablets with drug content ranging from 24 to 36 mg. The PLS calibration models for compression force and tensile strength were constructed using the same spectral set assuming both were highly related. These models yielded high R values (0.9955 and 0.9910). The R values of the moisture and mean particle size were 0.9994 and 0.9919, respectively. This study demonstrated that NIR spectroscopy combined with chemometric techniques can be successfully used to quantitatively monitor the tablet manufacturing process in the pharmaceutical industry. PMID:25738811

  8. Verification Of Residual Strength Properties From Compression After Impact Tests On Thin CFRP Skin, A1 Honeycomb Composites

    NASA Astrophysics Data System (ADS)

    Kalnins, Kaspars; Graham, Adrian J.; Sinnema, Gerben

    2012-07-01

    This article presents a study of CFRP/Al honeycomb panels subjected to a low velocity impact which, as a result, caused strength reduction. The main scope of the current study was to investigate experimental procedures, which are not well standardized and later verify them with numerical simulations. To ensure integrity of typical lightweight structural panels of modern spacecraft, knowledge about the impact energy required to produce clearly visible damage, and the resulting strength degradation is of high importance. For this initial investigation, Readily available ‘heritage’ (1980s) sandwich structure with relatively thin skin was used for this investigation. After initial attempts to produce impact damage, it was decided to create quasistatic indentation instead of low velocity impact, to cause barely visible damage. Forty two edgewise Compressions After Impact (CAI) test specimens have been produced and tested up to failure, while recording the strain distribution by optical means during the tests. Ultrasonic C-scan inspection was used to identify the damage evolution before and after each test. The optical strain measurements acquired during the tests showed sensitivity level capable to track the local buckling of damaged region.

  9. Large Scale Tests on Jointed and Bedded Rocks Under Multi-Stage Triaxial Compression and Direct Shear

    NASA Astrophysics Data System (ADS)

    Vergara, Maximiliano R.; Kudella, Peter; Triantafyllidis, Theodoros

    2015-01-01

    The mechanical behavior of bedded and jointed rock was examined in the context of the design of slopes, tunnels and tunnel portals along a planned new rail line. To obtain representative properties for describing the mechanical behavior of this material, large scale triaxial tests were performed. Specimens with a size of 60 cm diameter and 120 cm height composed of sandstone and claystone beds were tested in triaxial compression using a multi-stage technique. The specimens showed a ductile behavior for the stress regime tested. The strength parameters were calculated according to the Mohr-Coulomb failure criterion. The axial and volumetric deformations were measured and the viscosity of the composite rock material was assessed by deformation rate alterations. For some specimens, direct shear tests were conducted in samples containing joints. The results of the tests show that the failure of the bedded specimens was given by the combined failure of both materials. This was confirmed by a numerical model including rock discontinuities.

  10. A Discrete Element Model for Predicting Shear Strength and Degradation of Rock Joint by Using Compressive and Tensile Test Data

    NASA Astrophysics Data System (ADS)

    Kazerani, T.; Yang, Z. Y.; Zhao, J.

    2012-09-01

    A discrete element model is proposed to examine rock strength and failure. The model is implemented by UDEC, which is developed for this purpose. The material is represented as a collection of irregular-sized deformable particles interacting at their cohesive boundaries. The interface between two adjacent particles is viewed as a flexible contact whose constitutive law controls the material fracture and fragmentation properties. To reproduce rock anisotropy, an orthotropic cohesive law is developed for the contacts, which allows their shear and tensile behaviors to be different from each other. Using a combination of original closed-form expressions and statistical calibrations, a unique set of the contact microparameters are found based on the uniaxial/triaxial compression and Brazilian tension test data of a plaster. Applying the obtained microparameters, joint specimens, made of the same plaster, are simulated, where the comparison of the obtained results to laboratory data shows a reasonable agreement.

  11. Diametral compression test: Analysing the H/ D ratio influence on the mechanical resistance of UO 2-green pellets

    NASA Astrophysics Data System (ADS)

    Santana, H. H. S.; Maier, G.; Ródenas, J.

    2010-07-01

    Fired ceramic components and green compacted bodies from ceramic powder are both fragile structures. Their particles have weak mechanical links or are just agglomerated by a binder. Due to the compaction process failure can occur during unloading and ejection stages and also after a certain level of densification or powder cohesion has been achieved. Ceramic materials normally have worse standard deviation in the splitting tensile strength values when subjected to static or dynamic impact tests than metals. The height-to-diameter ( H/ D) ratio has been studied for several materials showing that by having different geometrical correlations the mechanical resistance of the tested specimens is highly affected. Cylindrical UO 2-green pellet samples, having approximately the same density with three different diameters and four different heights, were pressed and experimentally studied by means of the diametral compression (Brazilian) test. By combining the diameters and the heights different H/ D ratios could be tested. Results, which were analysed using Weibull statistics, showed that the cylinder size has a great influence on the Weibull module ( m), whereas for the Weibull tensile strength no conclusive tendency could be observed except if we keep the height fixed and increase the pellet diameter. Pellets having the same height showed an increased tendency for the m value if their diameter is increased. The largest volume by each diameter has the highest Weibull module values.

  12. Mechanical testing of hydrogels in cartilage tissue engineering: beyond the compressive modulus.

    PubMed

    Xiao, Yinghua; Friis, Elizabeth A; Gehrke, Stevin H; Detamore, Michael S

    2013-10-01

    Injuries to articular cartilage result in significant pain to patients and high medical costs. Unfortunately, cartilage repair strategies have been notoriously unreliable and/or complex. Biomaterial-based tissue-engineering strategies offer great promise, including the use of hydrogels to regenerate articular cartilage. Mechanical integrity is arguably the most important functional outcome of engineered cartilage, although mechanical testing of hydrogel-based constructs to date has focused primarily on deformation rather than failure properties. In addition to deformation testing, as the field of cartilage tissue engineering matures, this community will benefit from the addition of mechanical failure testing to outcome analyses, given the crucial clinical importance of the success of engineered constructs. However, there is a tremendous disparity in the methods used to evaluate mechanical failure of hydrogels and articular cartilage. In an effort to bridge the gap in mechanical testing methods of articular cartilage and hydrogels in cartilage regeneration, this review classifies the different toughness measurements for each. The urgency for identifying the common ground between these two disparate fields is high, as mechanical failure is ready to stand alongside stiffness as a functional design requirement. In comparing toughness measurement methods between hydrogels and cartilage, we recommend that the best option for evaluating mechanical failure of hydrogel-based constructs for cartilage tissue engineering may be tensile testing based on the single edge notch test, in part because specimen preparation is more straightforward and a related American Society for Testing and Materials (ASTM) standard can be adopted in a fracture mechanics context. PMID:23448091

  13. Radiological Image Compression

    NASA Astrophysics Data System (ADS)

    Lo, Shih-Chung Benedict

    The movement toward digital images in radiology presents the problem of how to conveniently and economically store, retrieve, and transmit the volume of digital images. Basic research into image data compression is necessary in order to move from a film-based department to an efficient digital -based department. Digital data compression technology consists of two types of compression technique: error-free and irreversible. Error -free image compression is desired; however, present techniques can only achieve compression ratio of from 1.5:1 to 3:1, depending upon the image characteristics. Irreversible image compression can achieve a much higher compression ratio; however, the image reconstructed from the compressed data shows some difference from the original image. This dissertation studies both error-free and irreversible image compression techniques. In particular, some modified error-free techniques have been tested and the recommended strategies for various radiological images are discussed. A full-frame bit-allocation irreversible compression technique has been derived. A total of 76 images which include CT head and body, and radiographs digitized to 2048 x 2048, 1024 x 1024, and 512 x 512 have been used to test this algorithm. The normalized mean -square-error (NMSE) on the difference image, defined as the difference between the original and the reconstructed image from a given compression ratio, is used as a global measurement on the quality of the reconstructed image. The NMSE's of total of 380 reconstructed and 380 difference images are measured and the results tabulated. Three complex compression methods are also suggested to compress images with special characteristics. Finally, various parameters which would effect the quality of the reconstructed images are discussed. A proposed hardware compression module is given in the last chapter.

  14. Life testing of the vapor compression distillation urine processor assembly (VCD/UPA) at the Marshall Space Flight Center.

    PubMed

    Wieland, P

    1998-01-01

    Wastewater and urine generated on the International Space Station (ISS) will be processed to recover pure water using vapor compression distillation (VCD). To verify the long-term reliability and performance of the VCD Urine Processor Assembly (UPA), life testing was performed at the Marshall Space Flight Center (MSFC) from January 1993 to April 1996. Two UPAs, the VCD-5 and VCD-5A, were tested for 204 days and 665 days, respectively. The compressor gears and the distillation centrifuge drive belt were found to have operating lives of approximately 4800 h, equivalent to 3.9 years of operation on ISS for a crew of three at an average processing rate of 1.76 kg/h (3.87 lb/h). Precise alignment of the flex-splines of the fluids and purge pump motor drives is essential to avoid premature failure after about 400 h of operation. Results indicate that, with some design and procedural modifications and suitable quality control, the required performance and operational life can be met with the VCD/UPA. PMID:11540460

  15. Life Testing of the Vapor Compression Distillation Urine Processing Assembly (VCD/UPA) at the Marshall Space Flight Center

    NASA Technical Reports Server (NTRS)

    Wieland, Paul O.

    1998-01-01

    Wastewater and urine generated on the International Space Station will be processed to recover pure water. The method selected is vapor compression distillation (VCD). To verify the long-term reliability and performance of the VCD Urine Processing Assembly (UPA), accelerated life testing was performed at the Marshall Space Flight Center (MSFC) from January 1993 to April 1996. Two UPAS, the VCD-5 and VCD-5A, were tested for 204 days and 665 days, respectively. The compressor gears and the distillation centrifuge drive belt were found to have an operating life of approximately 4800 hours. Precise alignment of the flex-spline of the fluids pump is essential to avoid failure of the pump after about 400 hours of operation. Also, leakage around the seals of the drive shaft of the fluids pump and purge pump must be eliminated for continued good performance. Results indicate that, with some design and procedural modifications and suitable quality control, the required performance and operational life can be met with the VCD/UPA.

  16. Gaia Payload Module Testing and Analysis Activities

    NASA Astrophysics Data System (ADS)

    Soula, Laurent

    2012-07-01

    The Gaia objective is to produce a very accurate catalogue of 1 billion of sky objects in our galaxy and beyond. ASTRIUM’s extensive experience on silicon carbide (SiC) instruments has helped developing the latest-generation payload module. It integrates the most sensitive and stable telescopes ever made, mounted on a SiC torus structure supported by three bipods. This payload module has been tested in June 2011 by ASTRIUM at INTESPACE facilities in Toulouse. To conduct the sine qualification tests and support the data analyses in real-time, advanced tools have been used. Most of them have been developed in a previous ESA R&D project [1] “DYNamics: AssessMent and Improvement of TEst Data (DYNAMITED)” and implemented in a DynaWorks® environment. Mass Operator calculation, to evaluate the payload module interface loads from measured accelerations, or automatic correlation through a criterion based on FRF from tests or predictions, are part of these tools. Testing such a structure also revealed some piloting difficulties due to a quite low and varying damping of the structure and a strong coupling with the shaker. To take into account such phenomena in the correlation work, enhanced simulations have also been performed considering multi-points phased excitations. These analyses demonstrate the payload module qualification status and allow derivate a more representative model to be used in further coupled system activities.

  17. Parallel image compression

    NASA Technical Reports Server (NTRS)

    Reif, John H.

    1987-01-01

    A parallel compression algorithm for the 16,384 processor MPP machine was developed. The serial version of the algorithm can be viewed as a combination of on-line dynamic lossless test compression techniques (which employ simple learning strategies) and vector quantization. These concepts are described. How these concepts are combined to form a new strategy for performing dynamic on-line lossy compression is discussed. Finally, the implementation of this algorithm in a massively parallel fashion on the MPP is discussed.

  18. An approach to compare the quality of cancellous bone from the femoral necks of healthy and osteoporotic patients through compression testing and microcomputed tomography imaging

    PubMed Central

    Ciarallo, Anthony; Barralet, Jake; Tanzer, Michael; Kremer, Richard

    2006-01-01

    It is estimated that osteoporosis is responsible for about 300 000 hip fractures per year in the United States. Effective prevention of these fractures has been demonstrated using bisphosphonates. However, their mechanism of action has not been elucidated. Furthermore, the precise effect of bisphosphonates on the femoral neck and surrounding areas has never been studied. We are interested in establishing a protocol to analyze the bone quality of proximal femurs from patients treated with bisphosphonates. Following hip replacement surgery, the aim is to determine whether imaging and compression testing of cancellous bone from the discarded femoral necks can accurately assess the bone’s microarchitectural and biomechanical properties, respectively. To validate the technique, it was first tested on an untreated population. A bone biopsy trephine was used to extract cylindrical cores of trabecular bone from the centre of femoral necks. Densitometry, microcomputed tomography, and compression testing were used to assess the quality of bone in these samples. The compressive strength was found to be directly proportional to the modulus (i.e. stiffness) of the samples, thus reproducing previous findings. The relative porosity and, to a lesser extent, the bone mineral density were capable of predicting the quality of cancellous bone. In conclusion, a protocol to analyze the bone quality in human femoral necks using μCT and biomechanical compression testing was successfully established. It will be applied in a clinical setting to analyze bones from bisphosphonate-treated patients following total hip replacement. PMID:18523625

  19. Development of optimization models for the set behavior and compressive strength of sodium activated geopolymer pastes

    NASA Astrophysics Data System (ADS)

    Fillenwarth, Brian Albert

    As large countries such as China begin to industrialize and concerns about global warming continue to grow, there is an increasing need for more environmentally friendly building materials. One promising material known as a geopolymer can be used as a portland cement replacement and in this capacity emits around 67% less carbon dioxide. In addition to potentially reducing carbon emissions, geopolymers can be synthesized with many industrial waste products such as fly ash. Although the benefits of geopolymers are substantial, there are a few difficulties with designing geopolymer mixes which have hindered widespread commercialization of the material. One such difficulty is the high variability of the materials used for their synthesis. In addition to this, interrelationships between mix design variables and how these interrelationships impact the set behavior and compressive strength are not well understood. A third complicating factor with designing geopolymer mixes is that the role of calcium in these systems is not well understood. In order to overcome these barriers, this study developed predictive optimization models through the use of genetic programming with experimentally collected set times and compressive strengths of several geopolymer paste mixes. The developed set behavior models were shown to predict the correct set behavior from the mix design over 85% of the time. The strength optimization model was shown to be capable of predicting compressive strengths of geopolymer pastes from their mix design to within about 1 ksi of their actual strength. In addition to this the optimization models give valuable insight into the key factors influencing strength development as well as the key factors responsible for flash set and long set behaviors in geopolymer pastes. A method for designing geopolymer paste mixes was developed from the generated optimization models. This design method provides an invaluable tool for use in future geopolymer research as well as

  20. Dynamic Docking Test System (DDTS) active table frequency response test results. [Apollo Soyuz Test Project

    NASA Technical Reports Server (NTRS)

    Gates, R. M.

    1974-01-01

    Results are presented of the frequency response test performed on the dynamic docking test system (DDTS) active table. Sinusoidal displacement commands were applied to the table and the dynamic response determined from measured actuator responses and accelerometers mounted to the table and one actuator.

  1. Emissions of toxic pollutants from compressed natural gas and low sulfur diesel-fueled heavy-duty transit buses tested over multiple driving cycles.

    PubMed

    Kado, Norman Y; Okamoto, Robert A; Kuzmicky, Paul A; Kobayashi, Reiko; Ayala, Alberto; Gebel, Michael E; Rieger, Paul L; Maddox, Christine; Zafonte, Leo

    2005-10-01

    The number of heavy-duty vehicles using alternative fuels such as compressed natural gas (CNG) and new low-sulfur diesel fuel formulations and equipped with after-treatment devices are projected to increase. However, few peer-reviewed studies have characterized the emissions of particulate matter (PM) and other toxic compounds from these vehicles. In this study, chemical and biological analyses were used to characterize the identifiable toxic air pollutants emitted from both CNG and low-sulfur-diesel-fueled heavy-duty transit buses tested on a chassis dynamometer over three transient driving cycles and a steady-state cruise condition. The CNG bus had no after-treatment, and the diesel bus was tested first equipped with an oxidation catalyst (OC) and then with a catalyzed diesel particulate filter (DPF). Emissions were analyzed for PM, volatile organic compounds (VOCs; determined on-site), polycyclic aromatic hydrocarbons (PAHs), and mutagenic activity. The 2000 model year CNG-fueled vehicle had the highest emissions of 1,3-butadiene, benzene, and carbonyls (e.g., formaldehyde) of the three vehicle configurations tested in this study. The 1998 model year diesel bus equipped with an OC and fueled with low-sulfur diesel had the highest emission rates of PM and PAHs. The highest specific mutagenic activities (revertants/microg PM, or potency) and the highest mutagen emission rates (revertants/mi) were from the CNG bus in strain TA98 tested over the New York Bus (NYB) driving cycle. The 1998 model year diesel bus with DPF had the lowest VOCs, PAH, and mutagenic activity emission. In general, the NYB driving cycle had the highest emission rates (g/mi), and the Urban Dynamometer Driving Schedule (UDDS) had the lowest emission rates for all toxics tested over the three transient test cycles investigated. Also, transient emissions were, in general, higher than steady-state emissions. The emissions of toxic compounds from an in-use CNG transit bus (without an oxidation

  2. Steady-state analysis of activated sludge processes with a settler model including sludge compression.

    PubMed

    Diehl, S; Zambrano, J; Carlsson, B

    2016-01-01

    A reduced model of a completely stirred-tank bioreactor coupled to a settling tank with recycle is analyzed in its steady states. In the reactor, the concentrations of one dominant particulate biomass and one soluble substrate component are modelled. While the biomass decay rate is assumed to be constant, growth kinetics can depend on both substrate and biomass concentrations, and optionally model substrate inhibition. Compressive and hindered settling phenomena are included using the Bürger-Diehl settler model, which consists of a partial differential equation. Steady-state solutions of this partial differential equation are obtained from an ordinary differential equation, making steady-state analysis of the entire plant difficult. A key result showing that the ordinary differential equation can be replaced with an approximate algebraic equation simplifies model analysis. This algebraic equation takes the location of the sludge-blanket during normal operation into account, allowing for the limiting flux capacity caused by compressive settling to easily be included in the steady-state mass balance equations for the entire plant system. This novel approach grants the possibility of more realistic solutions than other previously published reduced models, comprised of yet simpler settler assumptions. The steady-state concentrations, solids residence time, and the wastage flow ratio are functions of the recycle ratio. Solutions are shown for various growth kinetics; with different values of biomass decay rate, influent volumetric flow, and substrate concentration. PMID:26476681

  3. Fatigue behavior of carbon fiber reinforced epoxy composites -[{+-}45]{sub 4s} laminate under tension-tension and tension - compression fatigue loading test

    SciTech Connect

    Ma, C.C.M.; Tai, N.H.; Wu, G.Y.; Lin, S.H.

    1996-12-31

    Fatigue behaviors of carbon fiber reinforced epoxy laminated composite have been investigated. The [{+-}45]4S laminates of T300/976 Carbon/Epoxy were utilized. The static tensile strength and tension-tension tension-compression fatigue loading tests at various levels of stress amplitude were measured. The median rank method was applied to predict the statistical probability of experimental data of fatigue life. The S-N curves for various survival probabilities were established using the pooled Weibull distribution function. The theoretical prediction methods could be applied to illustrate the fatigue behavior of thermoset matrix polymer composites. Furthermore, the fatigue behaviors under tension - tension and tension-compression fatigue loading test were investigated. Both the stiffness degradation and the surface temperature change during fatigue test are discussed.

  4. Novel active signal compression in low-noise analog readout at future X-ray FEL facilities

    NASA Astrophysics Data System (ADS)

    Manghisoni, M.; Comotti, D.; Gaioni, L.; Lodola, L.; Ratti, L.; Re, V.; Traversi, G.; Vacchi, C.

    2015-04-01

    This work presents the design of a low-noise front-end implementing a novel active signal compression technique. This feature can be exploited in the design of analog readout channels for application to the next generation free electron laser (FEL) experiments. The readout architecture includes the low-noise charge sensitive amplifier (CSA) with dynamic signal compression, a time variant shaper used to process the signal at the preamplifier output and a 10-bit successive approximation register (SAR) analog-to-digital converter (ADC). The channel will be operated in such a way to cope with the high frame rate (exceeding 1 MHz) foreseen for future XFEL machines. The choice of a 65 nm CMOS technology has been made in order to include all the building blocks in the target pixel pitch of 100 μm. This work has been carried out in the frame of the PixFEL Project funded by the Istituto Nazionale di Fisica Nucleare (INFN), Italy.

  5. Design, construction, activation, and operation of a high intensity acoustic test chamber

    NASA Technical Reports Server (NTRS)

    Kamel, L. T.

    1986-01-01

    The design philosophy, construction, integration, and activation of the high intensity acoustic test chamber for production acceptance testing of satellites are discussed. The 32,000 cubic-foot acoustic test cell consists of a steel reinforced concrete chamber with six electropneumatic noise generators. One of the innovative features of the chamber is a unique quarter horn assembly that acoustically couples the noise generators to the chamber. Design concepts, model testing, and evaluation results are presented. Considerations such as nitrogen versus compressed air source, digital closed loop spectrum control versus manual equalizers, and microprocessor based interlock systems are included. Construction difficulties, anomalies encountered, and their resolution are also discussed. Results of the readiness testing are highlighted.

  6. Tensile and pack compressive tests of some sheets of aluminum alloy, 1025 carbon steel, and chromium-nickel steel

    NASA Technical Reports Server (NTRS)

    Atchison, C S; Miller, James A

    1942-01-01

    Tensile and compressive stress-strain curves, stress-deviation curves, and secant modulus-stress curves are given for longitudinal and transverse specimens of 17S-T, 24S-T, and 24S-RT aluminum-alloy sheet in thicknesses from 0.032 to 0.081 inch, 1025 carbon steel sheet in thicknesses of 0.054 and 0.120 inch, and chromium-nickel steel sheet in thicknesses form 0.020 to 0.0275 inch. Significant differences were found between the tensile and the compressive stress-strain curves, and also the corresponding corollary curves; similarly, differences were found between the curves for the longitudinal and transverse directions. These differences are of particular importance in considering the compressive strength of aircraft structures made of thin sheet. They are explored further for the case of compression by giving tangent modulus-stress curves in longitudinal and transverse compression and dimensionless curves of the ratio of tangent modulus to Young's modulus and of the ratio of reduced modulus for a rectangular section to Young's modulus, both plotted against the ratio of stress to secant yield strength.

  7. Compression embedding

    DOEpatents

    Sandford, II, Maxwell T.; Handel, Theodore G.; Bradley, Jonathan N.

    1998-01-01

    A method and apparatus for embedding auxiliary information into the digital representation of host data created by a lossy compression technique and a method and apparatus for constructing auxiliary data from the correspondence between values in a digital key-pair table with integer index values existing in a representation of host data created by a lossy compression technique. The methods apply to data compressed with algorithms based on series expansion, quantization to a finite number of symbols, and entropy coding. Lossy compression methods represent the original data as ordered sequences of blocks containing integer indices having redundancy and uncertainty of value by one unit, allowing indices which are adjacent in value to be manipulated to encode auxiliary data. Also included is a method to improve the efficiency of lossy compression algorithms by embedding white noise into the integer indices. Lossy compression methods use loss-less compression to reduce to the final size the intermediate representation as indices. The efficiency of the loss-less compression, known also as entropy coding compression, is increased by manipulating the indices at the intermediate stage. Manipulation of the intermediate representation improves lossy compression performance by 1 to 10%.

  8. Compression embedding

    DOEpatents

    Sandford, M.T. II; Handel, T.G.; Bradley, J.N.

    1998-07-07

    A method and apparatus for embedding auxiliary information into the digital representation of host data created by a lossy compression technique and a method and apparatus for constructing auxiliary data from the correspondence between values in a digital key-pair table with integer index values existing in a representation of host data created by a lossy compression technique are disclosed. The methods apply to data compressed with algorithms based on series expansion, quantization to a finite number of symbols, and entropy coding. Lossy compression methods represent the original data as ordered sequences of blocks containing integer indices having redundancy and uncertainty of value by one unit, allowing indices which are adjacent in value to be manipulated to encode auxiliary data. Also included is a method to improve the efficiency of lossy compression algorithms by embedding white noise into the integer indices. Lossy compression methods use loss-less compression to reduce to the final size the intermediate representation as indices. The efficiency of the loss-less compression, known also as entropy coding compression, is increased by manipulating the indices at the intermediate stage. Manipulation of the intermediate representation improves lossy compression performance by 1 to 10%. 21 figs.

  9. Triaxial- and uniaxial-compression testing methods developed for extraction of pore water from unsaturated tuff, Yucca Mountain, Nevada

    SciTech Connect

    Mower, T.E.; Higgins, J.D.; Yang, I.C.

    1989-12-31

    To support the study of hydrologic system in the unsaturated zone at Yucca Mountain, Nevada, two extraction methods were examined to obtain representative, uncontaminated pore-water samples from unsaturated tuff. Results indicate that triaxial compression, which uses a standard cell, can remove pore water from nonwelded tuff that has an initial moisture content greater than 11% by weight; uniaxial compression, which uses a specifically fabricated cell, can extract pore water from nonwelded tuff that has an initial moisture content greater than 8% and from welded tuff that has an initial moisture content greater than 6.5%. For the ambient moisture conditions of Yucca Mountain tuffs, uniaxial compression is the most efficient method of pore-water extraction. 12 refs., 7 figs., 2 tabs.

  10. Development of a Fast Breeder Reactor Fuel Bundle-Duct Interaction Analysis Code - BAMBOO: Analysis Model and Validation by the Out-of-Pile Compression Test

    SciTech Connect

    Uwaba, Tomoyuki; Tanaka, Kosuke

    2001-10-15

    To analyze the wire-wrapped fast breeder reactor (FBR) fuel pin bundle deformation under bundle-duct interaction (BDI) conditions, the Japan Nuclear Cycle Development Institute has developed the BAMBOO computer code. A three-dimensional beam element model is used in this code to calculate fuel pin bowing and cladding oval distortion, which are the dominant deformation mechanisms in a fuel pin bundle. In this work, the property of the cladding oval distortion considering the wire-pitch was evaluated experimentally and introduced in the code analysis.The BAMBOO code was validated in this study by using an out-of-pile bundle compression testing apparatus and comparing these results with the code results. It is concluded that BAMBOO reasonably predicts the pin-to-duct clearances in the compression tests by treating the cladding oval distortion as the suppression mechanism to BDI.

  11. Testing activities at the National Battery Test Laboratory

    NASA Astrophysics Data System (ADS)

    Hornstra, F.; Deluca, W. H.; Mulcahey, T. P.

    The National Battery Test Laboratory (NBTL) is an Argonne National Laboratory facility for testing, evaluating, and studying advanced electric storage batteries. The facility tests batteries developed under Department of Energy programs and from private industry. These include batteries intended for future electric vehicle (EV) propulsion, electric utility load leveling (LL), and solar energy storage. Since becoming operational, the NBTL has evaluated well over 1400 cells (generally in the form of three- to six-cell modules, but up to 140-cell batteries) of various technologies. Performance characterization assessments are conducted under a series of charge/discharge cycles with constant current, constant power, peak power, and computer simulated dynamic load profile conditions. Flexible charging algorithms are provided to accommodate the specific needs of each battery under test. Special studies are conducted to explore and optimize charge procedures, to investigate the impact of unique load demands on battery performance, and to analyze the thermal management requirements of battery systems.

  12. Compression embedding

    DOEpatents

    Sandford, II, Maxwell T.; Handel, Theodore G.; Bradley, Jonathan N.

    1998-01-01

    A method of embedding auxiliary information into the digital representation of host data created by a lossy compression technique. The method applies to data compressed with lossy algorithms based on series expansion, quantization to a finite number of symbols, and entropy coding. Lossy compression methods represent the original data as integer indices having redundancy and uncertainty in value by one unit. Indices which are adjacent in value are manipulated to encode auxiliary data. By a substantially reverse process, the embedded auxiliary data can be retrieved easily by an authorized user. Lossy compression methods use loss-less compressions known also as entropy coding, to reduce to the final size the intermediate representation as indices. The efficiency of the compression entropy coding, known also as entropy coding is increased by manipulating the indices at the intermediate stage in the manner taught by the method.

  13. Compression embedding

    DOEpatents

    Sandford, M.T. II; Handel, T.G.; Bradley, J.N.

    1998-03-10

    A method of embedding auxiliary information into the digital representation of host data created by a lossy compression technique is disclosed. The method applies to data compressed with lossy algorithms based on series expansion, quantization to a finite number of symbols, and entropy coding. Lossy compression methods represent the original data as integer indices having redundancy and uncertainty in value by one unit. Indices which are adjacent in value are manipulated to encode auxiliary data. By a substantially reverse process, the embedded auxiliary data can be retrieved easily by an authorized user. Lossy compression methods use loss-less compressions known also as entropy coding, to reduce to the final size the intermediate representation as indices. The efficiency of the compression entropy coding, known also as entropy coding is increased by manipulating the indices at the intermediate stage in the manner taught by the method. 11 figs.

  14. Evaluation of the robustness of the preprocessing technique improving reversible compressibility of CT images: Tested on various CT examinations

    SciTech Connect

    Jeon, Chang Ho; Kim, Bohyoung; Gu, Bon Seung; Lee, Jong Min; Kim, Kil Joong; Lee, Kyoung Ho; Kim, Tae Ki

    2013-10-15

    Purpose: To modify the preprocessing technique, which was previously proposed, improving compressibility of computed tomography (CT) images to cover the diversity of three dimensional configurations of different body parts and to evaluate the robustness of the technique in terms of segmentation correctness and increase in reversible compression ratio (CR) for various CT examinations.Methods: This study had institutional review board approval with waiver of informed patient consent. A preprocessing technique was previously proposed to improve the compressibility of CT images by replacing pixel values outside the body region with a constant value resulting in maximizing data redundancy. Since the technique was developed aiming at only chest CT images, the authors modified the segmentation method to cover the diversity of three dimensional configurations of different body parts. The modified version was evaluated as follows. In randomly selected 368 CT examinations (352 787 images), each image was preprocessed by using the modified preprocessing technique. Radiologists visually confirmed whether the segmented region covers the body region or not. The images with and without the preprocessing were reversibly compressed using Joint Photographic Experts Group (JPEG), JPEG2000 two-dimensional (2D), and JPEG2000 three-dimensional (3D) compressions. The percentage increase in CR per examination (CR{sub I}) was measured.Results: The rate of correct segmentation was 100.0% (95% CI: 99.9%, 100.0%) for all the examinations. The median of CR{sub I} were 26.1% (95% CI: 24.9%, 27.1%), 40.2% (38.5%, 41.1%), and 34.5% (32.7%, 36.2%) in JPEG, JPEG2000 2D, and JPEG2000 3D, respectively.Conclusions: In various CT examinations, the modified preprocessing technique can increase in the CR by 25% or more without concerning about degradation of diagnostic information.

  15. GLENOHUMERAL MUSCLE ACTIVATION DURING PROVOCATIVE TESTS DESIGNED TO DIAGNOSE SUPERIOR LABRUM ANTERIOR-POSTERIOR LESIONS

    PubMed Central

    Wood, Vanessa J.C.; Sabick, Michelle B.; Pfeiffer, Ron P.; Kuhlman, Seth M.; Christensen, Jason H.; Curtin, Michael J.

    2012-01-01

    Background Despite considerable medical advances, arthroscopy remains the only definitive means of Superior Labrum Anterior-Posterior (SLAP) lesion diagnosis. Natural shoulder anatomic variants limit the reliability of radiographic findings and clinical evaluations are not consistent. Accurate clinical diagnostic techniques would be advantageous due to the invasiveness, patient risk, and financial cost associated with arthroscopy. Purpose The purpose was to examine the behavior of the joint stabilizing muscles in provocative tests for SLAP lesions. Electromyography was used to characterize the muscle behavior, with particular interest in the long head biceps brachii (LHBB), as activation of the long head and subsequent tension in the biceps tendon should, based on related research, elicit labral symptoms in SLAP lesion patients. Study Design Controlled Laboratory Study Methods Volunteers (N=21) without a history of shoulder pathology were recruited. The tests analyzed were Active Compression, Speed's, Pronated Load, Biceps I, Biceps II, Resisted Supination External Rotation, and Yergason's. Tests were performed with a dynamometer to improve reproducibility. Muscle activity was recorded for the long and short heads of the biceps brachii, anterior deltoid, pectoralis major, latissimus dorsi, infraspinatus, and supraspinatus. Muscle behavior for each test was characterized by peak activation and proportion of muscle activity. Results Speed's, Active Compression Palm-Up, Bicep I and Bicep II, produced higher long head activations. Resisted Supination External Rotation, Bicep I, Bicep II, and Yergason's, produced a higher LHBB proportion. Conclusion Bicep I, and Bicep II elicited promising long head behavior (high activation and selectivity). Speed's and Active Compression Palm-Up elicited higher activation of the LHBB , and Resisted Supination and Yergason's elicited selective LHBB activity. These top performing tests utilize a unique range of test variables that may

  16. Compressive Holography

    NASA Astrophysics Data System (ADS)

    Lim, Se Hoon

    Compressive holography estimates images from incomplete data by using sparsity priors. Compressive holography combines digital holography and compressive sensing. Digital holography consists of computational image estimation from data captured by an electronic focal plane array. Compressive sensing enables accurate data reconstruction by prior knowledge on desired signal. Computational and optical co-design optimally supports compressive holography in the joint computational and optical domain. This dissertation explores two examples of compressive holography: estimation of 3D tomographic images from 2D data and estimation of images from under sampled apertures. Compressive holography achieves single shot holographic tomography using decompressive inference. In general, 3D image reconstruction suffers from underdetermined measurements with a 2D detector. Specifically, single shot holographic tomography shows the uniqueness problem in the axial direction because the inversion is ill-posed. Compressive sensing alleviates the ill-posed problem by enforcing some sparsity constraints. Holographic tomography is applied for video-rate microscopic imaging and diffuse object imaging. In diffuse object imaging, sparsity priors are not valid in coherent image basis due to speckle. So incoherent image estimation is designed to hold the sparsity in incoherent image basis by support of multiple speckle realizations. High pixel count holography achieves high resolution and wide field-of-view imaging. Coherent aperture synthesis can be one method to increase the aperture size of a detector. Scanning-based synthetic aperture confronts a multivariable global optimization problem due to time-space measurement errors. A hierarchical estimation strategy divides the global problem into multiple local problems with support of computational and optical co-design. Compressive sparse aperture holography can be another method. Compressive sparse sampling collects most of significant field

  17. 26 CFR 1.141-2 - Private activity bond tests.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... test and private security or payment test of section 141(b) or the private loan financing test of section 141(c). The private business use and private security or payment tests are described in §§ 1.141-3... 26 Internal Revenue 2 2014-04-01 2014-04-01 false Private activity bond tests. 1.141-2 Section...

  18. 26 CFR 1.141-2 - Private activity bond tests.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... test and private security or payment test of section 141(b) or the private loan financing test of section 141(c). The private business use and private security or payment tests are described in §§ 1.141-3... 26 Internal Revenue 2 2011-04-01 2011-04-01 false Private activity bond tests. 1.141-2 Section...

  19. Chronic Compression of the Dorsal Root Ganglion Enhances Mechanically Evoked Pain Behavior and the Activity of Cutaneous Nociceptors in Mice

    PubMed Central

    Wang, Tao; Hurwitz, Olivia; Shimada, Steven G.; Qu, Lintao; Fu, Kai; Zhang, Pu; Ma, Chao; LaMotte, Robert H.

    2015-01-01

    Radicular pain in humans is usually caused by intraforaminal stenosis and other diseases affecting the spinal nerve, root, or dorsal root ganglion (DRG). Previous studies discovered that a chronic compression of the DRG (CCD) induced mechanical allodynia in rats and mice, with enhanced excitability of DRG neurons. We investigated whether CCD altered the pain-like behavior and also the responses of cutaneous nociceptors with unmyelinated axons (C-fibers) to a normally aversive punctate mechanical stimulus delivered to the hairy skin of the hind limb of the mouse. The incidence of a foot shaking evoked by indentation of the dorsum of foot with an aversive von Frey filament (tip diameter 200 μm, bending force 20 mN) was significantly higher in the foot ipsilateral to the CCD surgery as compared to the contralateral side on post-operative days 2 to 8. Mechanically-evoked action potentials were electrophysiologically recorded from the L3 DRG, in vivo, from cell bodies visually identified as expressing a transgenically labeled fluorescent marker (neurons expressing either the receptor MrgprA3 or MrgprD). After CCD, 26.7% of MrgprA3+ and 32.1% MrgprD+ neurons exhibited spontaneous activity (SA), while none of the unoperated control neurons had SA. MrgprA3+ and MrgprD+ neurons in the compressed DRG exhibited, in comparison with neurons from unoperated control mice, an increased response to the punctate mechanical stimuli for each force applied (6, 20, 40, and 80 mN). We conclude that CCD produced both a behavioral hyperalgesia and an enhanced response of cutaneous C-nociceptors to aversive punctate mechanical stimuli. PMID:26356638

  20. First test experiment to produce the slowed-down RI beam with the momentum-compression mode at RIBF

    NASA Astrophysics Data System (ADS)

    Sumikama, T.; Ahn, D. S.; Fukuda, N.; Inabe, N.; Kubo, T.; Shimizu, Y.; Suzuki, H.; Takeda, H.; Aoi, N.; Beaumel, D.; Hasegawa, K.; Ideguchi, E.; Imai, N.; Kobayashi, T.; Matsushita, M.; Michimasa, S.; Otsu, H.; Shimoura, S.; Teranishi, T.

    2016-06-01

    The 82Ge beam has been produced by the in-flight fission reaction of the 238U primary beam with 345 MeV/u at the RIKEN RI beam factory, and slowed down to about 15 MeV/u using the energy degraders. The momentum-compression mode was applied to the second stage of the BigRIPS separator to reduce the momentum spread. The energy was successfully reduced down to 13 ± 2.5 MeV/u as expected. The focus was not optimized at the end of the second stage, therefore the beam size was larger than the expectation. The transmission of the second stage was half of the simulated value mainly due to out of focus. The two-stage separation worked very well for the slowed-down beam with the momentum-compression mode.

  1. Longitudinally Jointed Edge-Wise Compression HoneyComb Composite Sandwich Coupon Testing And Fe Analysis: Three Methods of Strain Measurement, And Comparison

    NASA Technical Reports Server (NTRS)

    Farrokh, Babak; Rahim, Nur Aida Abul; Segal, Ken; Fan, Terry; Jones, Justin; Hodges, Ken; Mashni, Noah; Garg, Naman; Sang, Alex

    2013-01-01

    Three distinct strain measurement methods (i.e., foil resistance strain gages, fiber optic strain sensors, and a three-dimensional digital image photogrammetry that gives full field strain and displacement measurements) were implemented to measure strains on the back and front surfaces of a longitudinally jointed curved test article subjected to edge-wise compression testing, at NASA Goddard Space Flight Center, according to ASTM C364. The pre-test finite element analysis (FEA) was conducted to assess ultimate failure load and predict strain distribution pattern throughout the test coupon. The predicted strain pattern contours were then utilized as guidelines for installing the strain measurement instrumentations. The foil resistance strain gages and fiber optic strain sensors were bonded on the specimen at locations with nearly the same analytically predicted strain values, and as close as possible to each other, so that, comparisons between the measured strains by strain gages and fiber optic sensors, as well as the three-dimensional digital image photogrammetric system are relevant. The test article was loaded to failure (at 167 kN), at the compressive strain value of 10,000 micro epsilon. As a part of this study, the validity of the measured strains by fiber optic sensors is examined against the foil resistance strain gages and the three-dimensional digital image photogrammetric data, and comprehensive comparisons are made with FEA predictions.

  2. Mechanical Testing of PMCs under Simulated Rapid Heat-Up Propulsion Environments. II; In-Plane Compressive Behavior

    NASA Technical Reports Server (NTRS)

    Stokes, Eric H.; Shin, E. Eugene; Sutter, James K.

    2003-01-01

    Carbon fiber thermoset polymer matrix composites (PMC) with high temperature polyimide based in-situ polymerized monomer reactant (PMR) resin has been used for some time in applications which can see temperatures up to 550 F. Currently, graphite fiber PMR based composites are used in several aircraft engine components including the outer bypass duct for the GE F-404, exit flaps for the P&W F-100-229, and the core cowl for the GE/Snecma CF6-80A3. Newer formulations, including PMR-II-50 are being investigated as potential weight reduction replacements of various metallic components in next generation high performance propulsion rocket engines that can see temperatures which exceed 550 F. Extensive FEM thermal modeling indicates that these components are exposed to rapid heat-up rates (up to -200 F/sec) and to a maximum temperature of around 600 F. Even though the predicted maximum part temperatures were within the capability of PW-II-50, the rapid heat-up causes significant through-thickness thermal gradients in the composite part and even more unstable states when combined with moisture. Designing composite parts for such extreme service environments will require accurate measurement of intrinsic and transient mechanical properties and the hygrothermal performance of these materials under more realistic use conditions. The mechanical properties of polymers degrade when exposed to elevated temperatures even in the absence of gaseous oxygen. Accurate mechanical characterization of the material is necessary in order to reduce system weight while providing sufficient factors of safety. Historically, the testing of PMCs at elevated temperatures has been plagued by the antagonism between two factors. First, moisture has been shown to profoundly affect the mechanical response of these materials at temperatures above their glass transition temperature while concurrently lowering the material's Tg. Moisture phenomena is due to one or a combination of three effects, i

  3. Goldstone field test activities: Target search

    NASA Technical Reports Server (NTRS)

    Tarter, J.

    1986-01-01

    In March of this year prototype SETI equipment was installed at DSS13, the 26 meter research and development antenna at NASA's Goldstone complex of satellite tracking dishes. The SETI equipment will remain at this site at least through the end of the summer so that the hardware and software developed for signal detection and recognition can be fully tested in a dynamic observatory environment. The field tests are expected to help understand which strategies for observing and which signal recognition algorithms perform best in the presence of strong man-made interfering signals (RFI) and natural astronomical sources.

  4. Compressible halftoning

    NASA Astrophysics Data System (ADS)

    Anderson, Peter G.; Liu, Changmeng

    2003-01-01

    We present a technique for converting continuous gray-scale images to halftone (black and white) images that lend themselves to lossless data compression with compression factor of three or better. Our method involves using novel halftone mask structures which consist of non-repeated threshold values. We have versions of both dispersed-dot and clustered-dot masks, which produce acceptable images for a variety of printers. Using the masks as a sort key allows us to reversibly rearrange the image pixels and partition them into groups with a highly skewed distribution allowing Huffman compression coding techniques to be applied. This gives compression ratios in the range 3:1 to 10:1.

  5. Recovery Efficiency Test Project: Phase 1, Activity report

    SciTech Connect

    Overbey, W.K. Jr.; Wilkins, D.W.; Keltch, B.; Saradji, B.; Salamy, S.P.

    1988-04-01

    This report is the second volume of the Recovery Efficiency Test Phase I Report of Activities. Volume 1 covered selection, well planning, drilling, coring, logging and completion operations. This volume reports on well testing activities, reclamation activities on the drilling site and access roads, and the results of physical and mechanical properties tests on the oriented core material obtained from a horizontal section of the well. 3 refs., 21 figs., 10 tabs.

  6. An Overview of Follow-On Testing Activities of the A-3 Subscale Diffuser Test Project

    NASA Technical Reports Server (NTRS)

    Ryan, James E.

    2009-01-01

    An overview of NASA Stennis Space Center's (SSC) A-3 Subscale Diffuser Test (SDT) Project is presented. The original scope of the SDT Project, conducted from April 2007 to January 2008, collected data to support mitigation of risk associated with design and procurement activities of the A-3 Test Stand Project, an effort to construct a simulated altitude test facility at SSC in support of NASA's Constellation Program. Follow-on tests were conducted from May 2008 through August 2009, utilizing the SDT test setup as a testbed for additional risk mitigation activities. Included are descriptions of the Subscale Diffuser (SD) test article, the test facility configuration, and test approaches.

  7. Transverse Compression of Tendons.

    PubMed

    Samuel Salisbury, S T; Paul Buckley, C; Zavatsky, Amy B

    2016-04-01

    A study was made of the deformation of tendons when compressed transverse to the fiber-aligned axis. Bovine digital extensor tendons were compression tested between flat rigid plates. The methods included: in situ image-based measurement of tendon cross-sectional shapes, after preconditioning but immediately prior to testing; multiple constant-load creep/recovery tests applied to each tendon at increasing loads; and measurements of the resulting tendon displacements in both transverse directions. In these tests, friction resisted axial stretch of the tendon during compression, giving approximately plane-strain conditions. This, together with the assumption of a form of anisotropic hyperelastic constitutive model proposed previously for tendon, justified modeling the isochronal response of tendon as that of an isotropic, slightly compressible, neo-Hookean solid. Inverse analysis, using finite-element (FE) simulations of the experiments and 10 s isochronal creep displacement data, gave values for Young's modulus and Poisson's ratio of this solid of 0.31 MPa and 0.49, respectively, for an idealized tendon shape and averaged data for all the tendons and E = 0.14 and 0.10 MPa for two specific tendons using their actual measured geometry. The compression load versus displacement curves, as measured and as simulated, showed varying degrees of stiffening with increasing load. This can be attributed mostly to geometrical changes in tendon cross section under load, varying according to the initial 3D shape of the tendon. PMID:26833218

  8. Why are Jupiter-family comets active and asteroids in cometary-like orbits inactive?. How hydrostatic compression leads to inactivity

    NASA Astrophysics Data System (ADS)

    Gundlach, B.; Blum, J.

    2016-05-01

    Context. Surveys in the visible and near-infrared spectral range have revealed the presence of low-albedo asteroids in cometary-like orbits (ACOs). In contrast to Jupiter-family comets (JFCs), ACOs are inactive, but possess similar orbital parameters. Aims: In this work, we discuss why ACOs are inactive, whereas JFCs show gas-driven dust activity, although both belong to the same class of primitive solar system bodies. Methods: We hypothesize that ACOs and JFCs have formed under the same physical conditions, namely by the gravitational collapse of ensembles of ice and dust aggregates. We use the memory effect of dust-aggregate layers under gravitational compression to discuss under which conditions the gas-driven dust activity of these bodies is possible. Results: Owing to their smaller sizes, JFCs can sustain gas-driven dust activity much longer than the bigger ACOs, whose sub-surface regions possess an increased tensile strength, due to gravitational compression of the material. The increased tensile strength leads to the passivation against dust activity after a relatively short time of activity. Conclusions: The gravitational-collapse model of the formation of planetesimals, together with the gravitational compression of the sub-surface material simultaneously, explains the inactivity of ACOs and the gas-driven dust activity of JFCs. Their initially larger sizes means that ACOs possess a higher tensile strength of their sub-surface material, which leads to a faster termination of gas-driven dust activity. Most objects with radii larger than 2 km have already lost their activity due to former gravitational compression of their current surface material.

  9. Verification of the FBR fuel bundle-duct interaction analysis code BAMBOO by the out-of-pile bundle compression test with large diameter pins

    NASA Astrophysics Data System (ADS)

    Uwaba, Tomoyuki; Ito, Masahiro; Nemoto, Junichi; Ichikawa, Shoichi; Katsuyama, Kozo

    2014-09-01

    The BAMBOO computer code was verified by results for the out-of-pile bundle compression test with large diameter pin bundle deformation under the bundle-duct interaction (BDI) condition. The pin diameters of the examined test bundles were 8.5 mm and 10.4 mm, which are targeted as preliminary fuel pin diameters for the upgraded core of the prototype fast breeder reactor (FBR) and for demonstration and commercial FBRs studied in the FaCT project. In the bundle compression test, bundle cross-sectional views were obtained from X-ray computer tomography (CT) images and local parameters of bundle deformation such as pin-to-duct and pin-to-pin clearances were measured by CT image analyses. In the verification, calculation results of bundle deformation obtained by the BAMBOO code analyses were compared with the experimental results from the CT image analyses. The comparison showed that the BAMBOO code reasonably predicts deformation of large diameter pin bundles under the BDI condition by assuming that pin bowing and cladding oval distortion are the major deformation mechanisms, the same as in the case of small diameter pin bundles. In addition, the BAMBOO analysis results confirmed that cladding oval distortion effectively suppresses BDI in large diameter pin bundles as well as in small diameter pin bundles.

  10. Designing an Active Target Test Projection Chamber

    NASA Astrophysics Data System (ADS)

    Koci, James; Tan Ahn Collaboration, Dr.; Nicolas Dixneuf Collaboration

    2015-10-01

    The development of instrumentation in nuclear physics is crucial for advancing our ability to measure the properties of exotic nuclei. One limitation of the use of exotic nuclei in experiment is their very low production intensities. Recently, detectors, called active-target dectectors, have been developed to address this issue. Active-target detectors use a gas medium to image charged-particle tracks that are emitted in nuclear reactions. Last semester, I designed a vacuum chamber to be used in developing Micro-Pattern Gas detectors that will upgrade the capabilities of an active-target detector called the Prototype AT-TPC. With the exterior of the chamber complete, I have now been using an electric field modeling program, Garfield, developed by CERN to design a field cage to be placed within the vacuum chamber. The field cage will be a box-like apparatus consisting of two parallel metal plates connected with a resistor chain and attached to wires wrapped between them. The cage will provide a uniform electric field within the chamber to drift electrons from nuclear reactions down to the detector in the bottom of the chamber. These signals are then amplified by a proportional counter, and the data is sent to a computer. For the long term, we would like to incorporate a Micro-Pattern Gas Detectors in the interior of the chamber and eventually use the AT-TPC to examine various nuclei. Dr. Ahn is my advising professor.

  11. Goldstone field test activities: Sky survey

    NASA Technical Reports Server (NTRS)

    Gulkis, S.; Olsen, E. T.

    1986-01-01

    The goals are to conduct a research and development program aimed at determining the most effective way to do SETI within the constraints of current technology and estimated budgets. The general search strategy adopted is that which is recommended by the SETI Science Working Group. The strategy for an all sky survey for SETI was further developed over the last year. Scan patterns, scan rates, and signal detection algorithms were developed. Spectral power measurement instrumentation was tested at the Venus Station of the Goldstone Deep Space Communication Complex. A specially designed radio frequency interference (RFI) measurement system was built and installed at the Venus Station. A data base management system for storage and retrieval of the RFI data was partially implemented on a VAX 750 computer at the Jet Propulsion Laboratory.

  12. 26 CFR 1.141-2 - Private activity bond tests.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 26 Internal Revenue 2 2013-04-01 2013-04-01 false Private activity bond tests. 1.141-2 Section 1.141-2 Internal Revenue INTERNAL REVENUE SERVICE, DEPARTMENT OF THE TREASURY (CONTINUED) INCOME TAX (CONTINUED) INCOME TAXES (CONTINUED) Tax Exemption Requirements for State and Local Bonds § 1.141-2 Private activity bond tests. (a) Overview....

  13. 26 CFR 1.141-2 - Private activity bond tests.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 26 Internal Revenue 2 2012-04-01 2012-04-01 false Private activity bond tests. 1.141-2 Section 1.141-2 Internal Revenue INTERNAL REVENUE SERVICE, DEPARTMENT OF THE TREASURY (CONTINUED) INCOME TAX (CONTINUED) INCOME TAXES (CONTINUED) Tax Exemption Requirements for State and Local Bonds § 1.141-2 Private activity bond tests. (a) Overview....

  14. Active infrared thermographic testing with distance heating

    NASA Astrophysics Data System (ADS)

    Ogasawara, N.; Ando, H.; Kobayashi, C.; Yamada, H.

    2015-05-01

    In order to efficiently inspect very wide area of concrete structure wall, an infrared thermographic testing with a distance heating was developed in this study. The researched subjects were the following three; 1. Improvement of radiant heating efficiency, 2. Development of distance heating method and 3. Development of data analysis method against nonuniformity of a heating and/or a wall absorptivity. In this paper, we focus on the first issue. In order to investigate about combinations between the spectral emissivity of radiant heater and the spectral absorptivity of concrete, three different types of radiant heater, a near infrared type, a far infrared type and blackbody type, were used to heat concrete specimens. As a results, both a blackbody type and a far infrared type, e.g. a ceramics heater and a blackbody coated heater, can heat a concrete wall more efficiently than a near infrared type, e.g. a halogen lamp heater and a xenon lamp heater. This is because the spectral absorptivity of concrete is higher in a far infrared region than in a near infrared region. We find that the efficiency of the heating process may be improved by choosing a heater whose radiation is concentrated near wavelengths at which the structure to be heated exhibits maximal absorptivity. The efficiency of the concrete heating process may be easily improved simply by covering the surface of a near infrared heater with a blackbody surface coating to mimic the radiation characteristics of a blackbody.

  15. Severe Accident Test Station Activity Report

    SciTech Connect

    Pint, Bruce A.; Terrani, Kurt A.

    2015-06-01

    Enhancing safety margins in light water reactor (LWR) severe accidents is currently the focus of a number of international R&D programs. The current UO2/Zr-based alloy fuel system is particularly susceptible since the Zr-based cladding experiences rapid oxidation kinetics in steam at elevated temperatures. Therefore, alternative cladding materials that offer slower oxidation kinetics and a smaller enthalpy of oxidation can significantly reduce the rate of heat and hydrogen generation in the core during a coolant-limited severe accident. In the U.S. program, the high temperature steam oxidation performance of accident tolerant fuel (ATF) cladding solutions has been evaluated in the Severe Accident Test Station (SATS) at Oak Ridge National Laboratory (ORNL) since 2012. This report summarizes the capabilities of the SATS and provides an overview of the oxidation kinetics of several candidate cladding materials. A suggested baseline for evaluating ATF candidates is a two order of magnitude reduction in the steam oxidation resistance above 1000ºC compared to Zr-based alloys. The ATF candidates are categorized based on the protective external oxide or scale that forms during exposure to steam at high temperature: chromia, alumina, and silica. Comparisons are made to literature and SATS data for Zr-based alloys and other less-protective materials.

  16. Video Compression

    NASA Technical Reports Server (NTRS)

    1996-01-01

    Optivision developed two PC-compatible boards and associated software under a Goddard Space Flight Center Small Business Innovation Research grant for NASA applications in areas such as telerobotics, telesciences and spaceborne experimentation. From this technology, the company used its own funds to develop commercial products, the OPTIVideo MPEG Encoder and Decoder, which are used for realtime video compression and decompression. They are used in commercial applications including interactive video databases and video transmission. The encoder converts video source material to a compressed digital form that can be stored or transmitted, and the decoder decompresses bit streams to provide high quality playback.

  17. Compression-Molding-Machine Tender (fabric. plastics prod.) 556.885--Technical Report on Development of USES Aptitude Test Battery.

    ERIC Educational Resources Information Center

    Manpower Administration (DOL), Washington, DC. U.S. Training and Employment Service.

    The United States Training and Employment Service General Aptitude Test Battery (GATB), first published in 1947, has been included in a continuing program of research to validate the tests against success in many different occupations. The GATB consists of 12 tests which measure nine aptitudes: General Learning Ability; Verbal Aptitude; Numerical…

  18. Utilization of fiber optic Bragg grating sensors in concrete columns confined with glass-fiber-reinforced plastic (GFRP) laminate under uniaxial compression test

    NASA Astrophysics Data System (ADS)

    Chan, Peter K. C.; Lau, Alan K.; Jin, Wei; Zhou, Limin

    1999-01-01

    In this paper we report of experimental studies on strain monitoring by using fiber Bragg grating sensors in concrete structures. The strain variation of the specimen under different loading conditions were monitored by the Fiber- optic Bragg grating (FBG) sensors. The FBG sensors have been pre-installed in the structure by embedding either inside the concrete specimen or at the interface between the concrete and the composites. The strain reading from the fiber grating sensor compares favorably with that obtained from the conventional strain gauge in uni-axial compression testing. The test result generally indicated that the concrete structures can be strengthened significantly by wrapping with glassfiber composites. The sensor embedded at the notch tip provides a very good indication of the health condition of the strengthened structure, especially in high stress concentration area. The strain sensitivity by using FBG sensor is 67 (mu) (epsilon) .

  19. [Compression material].

    PubMed

    Perceau, Géraldine; Faure, Christine

    2012-01-01

    The compression of a venous ulcer is carried out with the use of bandages, and for less exudative ulcers, with socks, stockings or tights. The system of bandages is complex. Different forms of extension and therefore different types of models exist. PMID:22489428

  20. Formulation of anisotropic Hill criteria for the description of an aluminium alloy behaviour during the channel die compression test

    SciTech Connect

    Gavrus, A.; Francillette, H.

    2007-04-07

    During the last years the study of the plastic deformation modes and the anisotropic mechanical behaviour of aluminium alloys have been the subject of many investigations. This paper deals with a phenomenological identification of an anisotropic Hill constitutive equation of aluminium AU4G samples using a channel die compression device at room temperature. By considering the different possible orientations of the samples in the channel die device, three initial textures, named ND (normal direction Z), LD (longitudinal direction X) and TD (transverse direction Y), were defined with the corresponding stresses {sigma}ND, {sigma}LD and {sigma}TD. To describe the anisotropy of the material, a quadratic Hill criteria is used. An Avrami type equation based on the mixture of the hardening and softening phenomena is used to describe variation of each stress component with the equivalent plastic strain. The identification of the parameters of the law is made using an identification software (OPTPAR) and a good correlation between the experimental stresses and computed ones is obtained. The variation of the Hill parameters with a proposed equivalent strain, describing the deformation history of the material, is analysed. Finally, using the expressions of F, G, H and N, the constitutive equation of the normal anisotropy in the plane XY is obtained.

  1. Strength Restoration of Cracked Sandstone and Coal under a Uniaxial Compression Test and Correlated Damage Source Location Based on Acoustic Emissions.

    PubMed

    Feng, Xiaowei; Zhang, Nong; Zheng, Xigui; Pan, Dongjiang

    2015-01-01

    Underground rock masses have shown a general trend of natural balance over billions of years of ground movement. Nonetheless, man-made underground constructions disturb this balance and cause rock stability failure. Fractured rock masses are frequently encountered in underground constructions, and this study aims to restore the strength of rock masses that have experienced considerable fracturing under uniaxial compression. Coal and sandstone from a deep-buried coal mine were chosen as experimental subjects; they were crushed by uniaxial compression and then carefully restored by a chemical adhesive called MEYCO 364 with an innovative self-made device. Finally, the restored specimens were crushed once again by uniaxial compression. Axial stress, axial strain, circumferential strain, and volumetric strain data for the entire process were fully captured and are discussed here. An acoustic emission (AE) testing system was adopted to cooperate with the uniaxial compression system to provide better definitions for crack closure thresholds, crack initiation thresholds, crack damage thresholds, and three-dimensional damage source locations in intact and restored specimens. Several remarkable findings were obtained. The restoration effects of coal are considerably better than those of sandstone because the strength recovery coefficient of the former is 1.20, whereas that of the latter is 0.33, which indicates that MEYCO 364 is particularly valid for fractured rocks whose initial intact peak stress is less than that of MEYCO 364. Secondary cracked traces of restored sandstone almost follow the cracked traces of the initial intact sandstone, and the final failure is mainly caused by decoupling between the adhesive and the rock mass. However, cracked traces of restored coal only partially follow the traces of intact coal, with the final failure of the restored coal being caused by both bonding interface decoupling and self-breakage in coal. Three-dimensional damage source

  2. Strength Restoration of Cracked Sandstone and Coal under a Uniaxial Compression Test and Correlated Damage Source Location Based on Acoustic Emissions

    PubMed Central

    Feng, Xiaowei; Zhang, Nong; Zheng, Xigui; Pan, Dongjiang

    2015-01-01

    Underground rock masses have shown a general trend of natural balance over billions of years of ground movement. Nonetheless, man-made underground constructions disturb this balance and cause rock stability failure. Fractured rock masses are frequently encountered in underground constructions, and this study aims to restore the strength of rock masses that have experienced considerable fracturing under uniaxial compression. Coal and sandstone from a deep-buried coal mine were chosen as experimental subjects; they were crushed by uniaxial compression and then carefully restored by a chemical adhesive called MEYCO 364 with an innovative self-made device. Finally, the restored specimens were crushed once again by uniaxial compression. Axial stress, axial strain, circumferential strain, and volumetric strain data for the entire process were fully captured and are discussed here. An acoustic emission (AE) testing system was adopted to cooperate with the uniaxial compression system to provide better definitions for crack closure thresholds, crack initiation thresholds, crack damage thresholds, and three-dimensional damage source locations in intact and restored specimens. Several remarkable findings were obtained. The restoration effects of coal are considerably better than those of sandstone because the strength recovery coefficient of the former is 1.20, whereas that of the latter is 0.33, which indicates that MEYCO 364 is particularly valid for fractured rocks whose initial intact peak stress is less than that of MEYCO 364. Secondary cracked traces of restored sandstone almost follow the cracked traces of the initial intact sandstone, and the final failure is mainly caused by decoupling between the adhesive and the rock mass. However, cracked traces of restored coal only partially follow the traces of intact coal, with the final failure of the restored coal being caused by both bonding interface decoupling and self-breakage in coal. Three-dimensional damage source

  3. Compression failure of composite laminates

    NASA Technical Reports Server (NTRS)

    Pipes, R. B.

    1983-01-01

    This presentation attempts to characterize the compressive behavior of Hercules AS-1/3501-6 graphite-epoxy composite. The effect of varying specimen geometry on test results is examined. The transition region is determined between buckling and compressive failure. Failure modes are defined and analytical models to describe these modes are presented.

  4. Longitudinally Jointed Edge-wise Compression Honeycomb Composite Sandwich Coupon Testing and FE Analysis: Three Methods of Strain Measurement, and Comparison

    NASA Technical Reports Server (NTRS)

    Farrokh, Babak; AbdulRahim, Nur Aida; Segal, Ken; Fan, Terry; Jones, Justin; Hodges, Ken; Mashni, Noah; Garg, Naman; Sang, Alex; Gifford, Dawn; Froggatt, Mark

    2013-01-01

    Three means (i.e., typical foil strain gages, fiber optic sensors, and a digital image correlation (DIC) system) were implemented to measure strains on the back and front surfaces of a longitudinally jointed curved test article subjected to edge-wise compression testing, at NASA Goddard Space Flight Center, according to ASTM C364. The Pre-test finite element analysis (FEA) was conducted to assess ultimate failure load and predict strain distribution pattern throughout the test coupon. The predicted strain pattern contours were then utilized as guidelines for installing the strain measurement instrumentations. The strain gages and fiber optic sensors were bonded on the specimen at locations with nearly the same strain values, as close as possible to each other, so that, comparisons between the measured strains by strain gages and fiber optic sensors, as well as the DIC system are justified. The test article was loaded to failure (at approximately 38 kips), at the strain value of approximately 10,000mu epsilon As a part of this study, the validity of the measured strains by fiber optic sensors is examined against the strain gage and DIC data, and also will be compared with FEA predictions.

  5. Orbiting dynamic compression laboratory

    NASA Technical Reports Server (NTRS)

    Ahrens, T. J.; Vreeland, T., Jr.; Kasiraj, P.; Frisch, B.

    1984-01-01

    In order to examine the feasibility of carrying out dynamic compression experiments on a space station, the possibility of using explosive gun launchers is studied. The question of whether powders of a refractory metal (molybdenum) and a metallic glass could be well considered by dynamic compression is examined. In both cases extremely good bonds are obtained between grains of metal and metallic glass at 180 and 80 kb, respectively. When the oxide surface is reduced and the dynamic consolidation is carried out in vacuum, in the case of molybdenum, tensile tests of the recovered samples demonstrated beneficial ultimate tensile strengths.

  6. Energy-efficiency testing activities of the Mobile Energy Laboratory

    SciTech Connect

    Parker, G.B.

    1991-01-01

    This report summarizes energy-efficiency testing activities during the first and second quarters of fiscal year 1990 applying the Mobile Energy Laboratory (MEL) testing capabilities. Four MELs, developed by the US Department of Energy (DOE) Federal Energy Management Program (FEMP), are administered by Pacific Northwest Laboratory (PNL) for energy testing and program support functions at federal facilities. The using agencies principally fund MEL applications, while DOE/FEMP funds program administration and capability enhancement activities. This report fulfills the requirements established in the MEL Use Plan (PNL-6861) for semiannual reporting on energy-efficiency testing activities using the MEL capabilities. The MEL Use Committee, formally established in 1989, developed the MEL Use Plan and meets semiannually to establish priorities for energy-efficient testing applications using the MEL capabilities.

  7. Launch Deployment Assembly Extravehicular Activity Neutral Buoyancy Development Test Report

    NASA Technical Reports Server (NTRS)

    Loughead, T.

    1996-01-01

    This test evaluated the Launch Deployment Assembly (LDA) design for Extravehicular Activity (EVA) work sites (setup, igress, egress), reach and visual access, and translation required for cargo item removal. As part of the LDA design, this document describes the method and results of the LDA EVA Neutral Buoyancy Development Test to ensure that the LDA hardware support the deployment of the cargo items from the pallet. This document includes the test objectives, flight and mockup hardware description, descriptions of procedures and data collection used in the testing, and the results of the development test at the National Aeronautics and Space Administrations (NASA) Marshall Space Flight Center (MSFC) Neutral Buoyancy Simulator (NBS).

  8. 30 CFR 75.1106-5 - Maintenance and tests of liquefied and nonliquefied compressed gas cylinders; accessories and...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... cylinders, cylinder accessories, torches, and other welding, cutting, and burning equipment shall be labeled... to maintain torches in a safe operating condition. (d) Tests for leaks on the hose valves or gages...

  9. 30 CFR 75.1106-5 - Maintenance and tests of liquefied and nonliquefied compressed gas cylinders; accessories and...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... cylinders, cylinder accessories, torches, and other welding, cutting, and burning equipment shall be labeled... to maintain torches in a safe operating condition. (d) Tests for leaks on the hose valves or gages...

  10. 30 CFR 75.1106-5 - Maintenance and tests of liquefied and nonliquefied compressed gas cylinders; accessories and...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... cylinders, cylinder accessories, torches, and other welding, cutting, and burning equipment shall be labeled... to maintain torches in a safe operating condition. (d) Tests for leaks on the hose valves or gages...

  11. 30 CFR 75.1106-5 - Maintenance and tests of liquefied and nonliquefied compressed gas cylinders; accessories and...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... cylinders, cylinder accessories, torches, and other welding, cutting, and burning equipment shall be labeled... to maintain torches in a safe operating condition. (d) Tests for leaks on the hose valves or gages...

  12. 30 CFR 75.1106-5 - Maintenance and tests of liquefied and nonliquefied compressed gas cylinders; accessories and...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... cylinders, cylinder accessories, torches, and other welding, cutting, and burning equipment shall be labeled... to maintain torches in a safe operating condition. (d) Tests for leaks on the hose valves or gages...

  13. Authenticity examination of compressed audio recordings using detection of multiple compression and encoders' identification.

    PubMed

    Korycki, Rafal

    2014-05-01

    Since the appearance of digital audio recordings, audio authentication has been becoming increasingly difficult. The currently available technologies and free editing software allow a forger to cut or paste any single word without audible artifacts. Nowadays, the only method referring to digital audio files commonly approved by forensic experts is the ENF criterion. It consists in fluctuation analysis of the mains frequency induced in electronic circuits of recording devices. Therefore, its effectiveness is strictly dependent on the presence of mains signal in the recording, which is a rare occurrence. Recently, much attention has been paid to authenticity analysis of compressed multimedia files and several solutions were proposed for detection of double compression in both digital video and digital audio. This paper addresses the problem of tampering detection in compressed audio files and discusses new methods that can be used for authenticity analysis of digital recordings. Presented approaches consist in evaluation of statistical features extracted from the MDCT coefficients as well as other parameters that may be obtained from compressed audio files. Calculated feature vectors are used for training selected machine learning algorithms. The detection of multiple compression covers up tampering activities as well as identification of traces of montage in digital audio recordings. To enhance the methods' robustness an encoder identification algorithm was developed and applied based on analysis of inherent parameters of compression. The effectiveness of tampering detection algorithms is tested on a predefined large music database consisting of nearly one million of compressed audio files. The influence of compression algorithms' parameters on the classification performance is discussed, based on the results of the current study. PMID:24637036

  14. Predicting Work Activities with Divergent Thinking Tests: A Longitudinal Study

    ERIC Educational Resources Information Center

    Clapham, Maria M.; Cowdery, Edwina M.; King, Kelly E.; Montang, Melissa A.

    2005-01-01

    This study examined whether divergent thinking test scores obtained from engineering students during college predicted creative work activities fifteen years later. Results showed that a subscore of the "Owens Creativity Test", which assesses divergent thinking about mechanical objects, correlated significantly with self-ratings of creative work…

  15. Terminal-shock and restart control of a Mach 2.5, axisymmetric, mixed compression inlet with 40 percent internal contraction. [wind tunnel tests

    NASA Technical Reports Server (NTRS)

    Baumbick, R. J.

    1974-01-01

    Results of experimental tests conducted on a supersonic, mixed-compression, axisymmetric inlet are presented. The inlet is designed for operation at Mach 2.5 with a turbofan engine (TF-30). The inlet was coupled to either a choked orifice plate or a long duct which had a variable-area choked exit plug. Closed-loop frequency responses of selected diffuser static pressures used in the terminal-shock control system are presented. Results are shown for Mach 2.5 conditions with the inlet coupled to either the choked orifice plate or the long duct. Inlet unstart-restart traces are also presented. High-response inlet bypass doors were used to generate an internal disturbance and also to achieve terminal-shock control.

  16. Compression and immersion tests and leaching of radionuclides, stable metals, and chelating agents from cement-solidified decontamination waste collected from nuclear power stations

    SciTech Connect

    Akers, D.W.; Kraft, N.C.; Mandler, J.W.

    1994-06-01

    A study was performed for the Nuclear Regulatory Commission (NRC) to evaluate structural stability and leachability of radionuclides, stable metals, and chelating agents from cement-solidified decontamination ion-exchange resin wastes collected from seven commercial boiling water reactors and one pressurized water reactor. The decontamination methods used at the reactors were the Can-Decon, AP/Citrox, Dow NS-1, and LOMI processes. Samples of untreated resin waste and solidified waste forms were subjected to immersion and compressive strength testing. Some waste-form samples were leach-tested using simulated groundwaters and simulated seawater for comparison with the deionized water tests that are normally performed to assess waste-form leachability. This report presents the results of these tests and assesses the effects of the various decontamination methods, waste form formulations, leachant chemical compositions, and pH of the leachant on the structural stability and leachability of the waste forms. Results indicate that releases from intact and degraded waste forms are similar and that the behavior of some radionuclides such as {sup 55}Fe, {sup 60}Co, and {sup 99}Tc were similar. In addition, the leachability indexes are greater than 6.0, which meets the requirement in the NRC`s ``Technical Position on Waste Form,`` Revision 1.

  17. Physical Activity and Cervical Cancer Testing among American Indian Women

    ERIC Educational Resources Information Center

    Muus, Kyle J.; Baker-Demaray, Twyla B.; Bogart, T. Andy; Duncan, Glen E.; Jacobsen, Clemma; Buchwald, Dedra S.; Henderson, Jeffrey A.

    2012-01-01

    Purpose: Studies have shown that women who engage in high levels of physical activity have higher rates of cancer screening, including Papanicalaou (Pap) tests. Because American Indian (AI) women are at high risk for cervical cancer morbidity and mortality, we examined Pap screening prevalence and assessed whether physical activity was associated…

  18. Effects of Vigorous Intensity Physical Activity on Mathematics Test Performance

    ERIC Educational Resources Information Center

    Phillips, David S.; Hannon, James C.; Castelli, Darla M.

    2015-01-01

    The effect of an acute bout of physical activity on academic performance in school-based settings is under researched. The purpose of this study was to examine associations between a single, vigorous (70-85%) bout of physical activity completed during physical education on standardized mathematics test performance among 72, eighth grade students…

  19. Active Protection of an MgB2 Test Coil

    PubMed Central

    Park, Dong Keun; Hahn, Seungyong; Bascuñán, Juan; Iwasa, Yukikazu

    2011-01-01

    This paper presents results of a study, experimental and computational, of a detect-and-activate-the-heater protection technique applied to a magnesium diboride (MgB2) test coil operated in semi-persistent mode. The test coil with a winding ID of 25 cm and wound with ~500-m long reacted MgB2 wire was operated at 4.2 K immersed in a bath of liquid helium. In this active technique, upon the initiation of a “hot spot” of a length ~10 cm, induced by a “quench heater,” a “protection heater” (PH) of ~600-cm long planted within the test coil is activated. The normal zone created by the PH is large enough to absorb the test coil’s entire initial stored energy and still keeps the peak temperature within the winding below ~260 K. PMID:22081754

  20. Standard test method for compressive strength of grouts for preplaced-aggregate concrete in the laboratory. ASTM standard

    SciTech Connect

    1998-10-01

    DoD adopted. This test method is under the jurisdiction of ASTM Committee C-9 on Concrete and Concrete Aggregates and is the direct responsibility of Subcommittee C09.41 on Concrete for Radiation Shielding. Current edition approved Feb. 10, 1986 and published October 1998. Originally published as C 942-81. Last previous edition was C 942-86(1991).

  1. Comparison of Artificial Compressibility Methods

    NASA Technical Reports Server (NTRS)

    Kiris, Cetin; Housman, Jeffrey; Kwak, Dochan

    2004-01-01

    Various artificial compressibility methods for calculating the three-dimensional incompressible Navier-Stokes equations are compared. Each method is described and numerical solutions to test problems are conducted. A comparison based on convergence behavior, accuracy, and robustness is given.

  2. A Review of Sub-Scale Test Methods to Evaluate the Friction and Wear of Ring and Liner Materials for Spark- and Compression Ignition Engines

    SciTech Connect

    Blau, P.J.

    2002-01-22

    A review was conducted of past laboratory-scale test methods and to assess their validity for ranking materials and lubricants for use as piston and liner materials in compression-ignition (CI) and spark-ignition (SI) engines. Most of the previous work was aimed at simulating SI engine environments. This report begins with a discussion of the numerous factors that can affect the validity of an approach to simulating engine conditions in a laboratory. These include not only mechanical, chemical and thermal factors, but also human factors as regards how the vehicle is operated and maintained. The next section provides an annotated review of open literature publications that address the issues of laboratory simulation of engine components. A comparison of these studies indicates a lack of sufficient standardization in procedures to enable a systematic comparison of one publication to another. There were just a few studies that compared several laboratory test methods to engine test results, and these indicated that some test methods correlate, at least qualitatively, better than others. The last section provides a series of recommendations for improving the accuracy and validity of laboratory-scale simulations of engine behavior. It became clear that much of the engine wear damage occurs during start-up when the engine is cold, and this calls into the question the usefulness of test methods that attempt to simulate steady-state running conditions. It is recommended that a new standard test method, perhaps developed with the help of the ASTM wear and erosion committee, be developed. It would use cold start-up conditions in the presence of degraded oil, or simulated degraded oil.

  3. Active control rotor model testing at Princeton's Rotorcraft Dynamics Laboratory

    NASA Technical Reports Server (NTRS)

    Mckillip, Robert M., Jr.

    1988-01-01

    A description of the model helicopter rotor tests currently in progress at Princeton's Rotorcraft Dynamics Laboratory is presented. The tests are designed to provide data for rotor dynamic modeling for use with active control system design. The model rotor to be used incoporates the capability for Individual Blade Control (IBC) or Higher Harmonic Control through the use of a standard swashplate on a three bladed hub. Sample results from the first series of tests are presented, along with the methodology used for state and parameter identification. Finally, pending experiments and possible research directions using this model and test facility are outlined.

  4. Exclusion and diagnosis of deep vein thrombosis by a rapid ELISA D-dimer test, compression ultrasonography, and a simple clinical model.

    PubMed

    Michiels, J J; Oortwijn, W J; Naaborg, R

    1999-07-01

    The classical clinical signs of deep vein thrombosis (DVT) are unspecific and may be found in several other conditions besides DVT. Therefore, patients suspicious of DVT are subjected to elaborate invasive or noninvasive evidence-based procedures that actually confirm DVT in only 20% to 30% of patients in this setting. However, simple laboratory tests and noninvasive strategies to exclude and diagnose DVT are becoming available in the clinical emergency setting of outpatients. In the presented literature, a sound basis is provided for quantifying clinical judgment for the diagnosis of acute proximal DVT. The number of positive clinical findings at time of first suspicion of DVT appears to correlate directly with the probability of acute proximal DVT. The modified clinical model of Landefeld and Wells for DVT allows reasonable accurate classification of patients into low, moderate, and high probability for suffering DVT. The rapid automated enzyme-linked immunoabsorbant assay (ELISA) VIDAS D-dimer presently available can be rapidly performed in daily practice and emergency situations and is accurate to a high degree, especially in ruling out ongoing venous thromboembolic processes. The sequential use of the rapid ELISA VIDAS D-dimer test and compression ultrasonography in a well-designed clinical setting using a simple clinical model predicts a significant improvement due to a high sensitivity near 100% for the exclusion and diagnosis of DVT in the majority of outpatients with suspect DVT. A prospective decision analysis management study is proposed to exclude and diagnose DVT based on the rapid ELISA VIDAS D-dimer test and compression ultrasonography within the context of a ready-to-use simple clinical model. The proposed simple model of a rational diagnosis of deep vein thrombosis (RADIA DVT) has to be tested in a large multicenter study of more than 1,000 outpatients with suspected DVT. This model would be less expensive, easy to perform, and likely yield a

  5. U.S. Department of Energy -- Advanced Vehicle Testing Activity: Plug-in Hybrid Electric Vehicle Testing and Demonstration Activities

    SciTech Connect

    James E. Francfort; Donald Karner; John G. Smart

    2009-05-01

    The U.S. Department of Energy’s (DOE) Advanced Vehicle Testing Activity (AVTA) tests plug-in hybrid electric vehicles (PHEV) in closed track, dynamometer and onroad testing environments. The onroad testing includes the use of dedicated drivers on repeated urban and highway driving cycles that range from 10 to 200 miles, with recharging between each loop. Fleet demonstrations with onboard data collectors are also ongoing with PHEVs operating in several dozen states and Canadian Provinces, during which trips- and miles-per-charge, charging demand and energy profiles, and miles-per-gallon and miles-per-kilowatt-hour fuel use results are all documented, allowing an understanding of fuel use when vehicles are operated in charge depleting, charge sustaining, and mixed charge modes. The intent of the PHEV testing includes documenting the petroleum reduction potential of the PHEV concept, the infrastructure requirements, and operator recharging influences and profiles. As of May 2008, the AVTA has conducted track and dynamometer testing on six PHEV conversion models and fleet testing on 70 PHEVs representing nine PHEV conversion models. A total of 150 PHEVs will be in fleet testing by the end of 2008, all with onboard data loggers. The onroad testing to date has demonstrated 100+ miles per gallon results in mostly urban applications for approximately the first 40 miles of PHEV operations. The primary goal of the AVTA is to provide advanced technology vehicle performance benchmark data for technology modelers, research and development programs, and technology goal setters. The AVTA testing results also assist fleet managers in making informed vehicle purchase, deployment and operating decisions. The AVTA is part of DOE’s Vehicle Technologies Program. These AVTA testing activities are conducted by the Idaho National Laboratory and Electric Transportation Engineering Corporation, with Argonne National Laboratory providing dynamometer testing support. The proposed paper

  6. Compressed natural gas measurement issues

    SciTech Connect

    Blazek, C.F.; Kinast, J.A.; Freeman, P.M.

    1993-12-31

    The Natural Gas Vehicle Coalition`s Measurement and Metering Task Group (MMTG) was established on July 1st, 1992 to develop suggested revisions to National Institute of Standards & Technology (NIST) Handbook 44-1992 (Specifications, Tolerances, and Other Technical Requirements for Weighing and Measuring Devices) and NIST Handbook 130-1991 (Uniform Laws & Regulations). Specifically, the suggested revisions will address the sale and measurement of compressed natural gas when sold as a motor vehicle fuel. This paper briefly discusses the activities of the MMTG and its interaction with NIST. The paper also discusses the Institute of Gas Technology`s (IGT) support of the MMTG in the area of natural gas composition, their impact on metering technology applicable to high pressure fueling stations as well as conversion factors for the establishment of ``gallon gasoline equivalent`` of natural gas. The final portion of this paper discusses IGT`s meter research activities and its meter test facility.

  7. Electromagnetic ion cyclotron waves stimulated by modest magnetospheric compressions

    NASA Technical Reports Server (NTRS)

    Anderson, B. J.; Hamilton, D. C.

    1993-01-01

    AMPTE/CCE magnetic field and particle data are used to test the suggestion that increased hot proton temperature anisotropy resulting from convection during magnetospheric compression is responsible for the enhancement in Pc 1 emission via generation of electromagnetic ion cyclotron (EMIC) waves in the dayside outer equatorial magnetosphere. The relative increase in magnetic field is used to gauge the strength of the compression, and an image dipole model is used to estimate the motion of the plasma during compression. Proton data are used to analyze the evolution of the proton distribution and the corresponding changes in EMIC wave activity expected during the compression. It is suggested that enhancements in dynamic pressure pump the energetic proton distributions in the outer magnetosphere, driving EMIC waves. Waves are expected to be generated most readily close to the magnetopause, and transient pressure pulses may be associated with bursts of EMIC waves, which would be observed on the ground in association with ionospheric transient signatures.

  8. Multiphase, Multicomponent Compressibility in Geothermal Reservoir Engineering

    SciTech Connect

    Macias-Chapa, L.; Ramey, H.J. Jr.

    1987-01-20

    Coefficients of compressibilities below the bubble point were computer with a thermodynamic model for single and multicomponent systems. Results showed coefficients of compressibility below the bubble point larger than the gas coefficient of compressibility at the same conditions. Two-phase compressibilities computed in the conventional way are underestimated and may lead to errors in reserve estimation and well test analysis. 10 refs., 9 figs.

  9. [Application of basophil activation test in diagnosing aspirin hypersensitivity].

    PubMed

    Gawinowska, Marika; Specjalski, Krzysztof; Chełmińska, Marta; Łata, Jakub; Zieliński, Maciej

    2015-01-01

    In the face of increasing prevalence of hypersensitivity reactions, introduction of effective, reliable and safe methods plays a crucial role in their diagnosing. Among the currently available laboratory (in vitro) methods is basophil activation test (BAT). It is a flow- cytometry based assay that allows to identificate in the blood sample basophils and additionally to asses the degree of cell activation after exposure to an antigen. The most common superficial identification markers are CD63 and CD203c, which increase in number after activation. Basophil actvation test can be applied to confirm diagnosis of allergy to Hymenoptera venoms, food, pollens and hypersensitivity to drugs. The aim of present paper is to present theoretical methods of this test as well as its pros and cons. We focus also on presentation of clinical case where BAT seemed to be a necessary addition to a routine diagnostic pathway. We present a case of identification of the culprit drug which caused an anaphylactic reaction. PMID:25577537

  10. Space shuttle orbiter approach and landing test evaluation report. Captive-active flight test summary

    NASA Technical Reports Server (NTRS)

    1977-01-01

    Captive-active tests consisted of three mated carrier aircraft/Orbiter flights with an active manned Orbiter. The objectives of this series of flights were to (1) verify the separation profile, (2) verify the integrated structure, aerodynamics, and flight control system, (3) verify Orbiter integrated system operations, and (4) refine and finalize carrier aircraft, Orbiter crew, and ground procedures in preparation for free flight tests. A summary description of the flights is presented with assessments of flight test requirements, and of the performance operations, and of significant flight anomalies is included.

  11. A data base and a standard material for use in acceptance testing of low-activity waste products

    SciTech Connect

    Wolf, S.F.; Ebert, W.L.; Luo, J.S.; Strachan, D.M.

    1998-04-01

    The authors have conducted replicate dissolution tests following the product consistency test (PCT) procedure to measure the mean and standard deviation of the solution concentrations of B, Na, and Si at various combinations of temperature, duration, and glass/water mass ratio. Tests were conducted with a glass formulated to be compositionally similar to low-activity waste products anticipated for Hanford to evaluate the adequacy of test methods that have been designated in privatization contracts for use in product acceptance. An important finding from this set of tests is that the solution concentrations generated in tests at 20 C will likely be too low to measure the dissolution rates of waste products reliably. Based on these results, the authors recommend that the acceptance test be conducted at 40 C. Tests at 40 C generated higher solution concentrations, were more easily conducted, and the measured rates were easily related to those at 20 C. Replicate measurements of other glass properties were made to evaluate the possible use of LRM-1 as a standard material. These include its composition, homogeneity, density, compressive strength, the Na leachability index with the ANSI/ANS 16.1 leach test, and if the glass is characteristically hazardous with the toxicity characteristic leach procedure. The values of these properties were within the acceptable limits identified for Hanford low-activity waste products. The reproducibility of replicate tests and analyses indicates that the glass would be a suitable standard material.

  12. Pore-water extraction from unsaturated tuff by triaxial and one-dimensional compression methods, Nevada Test Site, Nevada

    SciTech Connect

    Mower, T.E.; Higgins, J.D.; Yang, In C.; Peters, C.A.

    1994-07-01

    The hydrologic system in the unsaturated tuff at Yucca Mountain, Nevada, is being evaluated for the US Department of Energy by the Yucca Mountain Project Branch of the US Geological Survey as a potential site for a high-level radioactive-waste repository. Part of this investigation includes a hydrochemical study that is being made to assess characteristics of the hydrologic system such as: traveltime, direction of flow, recharge and source relations, and types and magnitudes of chemical reactions in the unsaturated tuff. In addition, this hydrochemical information will be used in the study of the dispersive and corrosive effects of unsaturated-zone water on the radioactive-waste storage canisters. This report describes the design and validation of laboratory experimental procedures for extracting representative samples of uncontaminated pore water from welded and nonwelded, unsaturated tuffs from the Nevada Test Site.

  13. Development and testing of an active platen for IC manufacturing

    SciTech Connect

    Redmond, J.; Barney, P.; Smith, T.; Darnold, J.

    1998-11-01

    The conflicting demands for finer features and increased production rates in integrated circuit manufacturing have emphasized the need for improved wafer positioning technology. In this paper we present operational test results from a magnetically levitated platen with structurally integrated piezoelectric acctuators. The strain based actuators provide active damping of the platen`s flexible body modes, enabling increased bandwidth on the mag-lev positioning system. Test results reveal a dramatic reduction in steady state positioning error and settling time through implementation of active vibration control.

  14. Effect of strain rates from 10/sup -2/ to 10 sec/sup -1/ in triaxial compression tests on three rocks

    SciTech Connect

    Blanton, T.L.

    1981-02-01

    Room-temperature, compression tests at strain rates from 10/sup -2/ to 10 sec/sup -1/ have been run on Charcoal Granodiorite to 0.45 GPa confining pressure and on Berea Sandstone and Indiana Limestone to 0.25 GPa confining pressure. For each rock at each confining pressure, the differential stress at failure is relatively constant up to a strain rate of 1 sec/sup -1/ and apparently increases abruptly above this strain rate. Dynamic analysis of the testing apparatus indicates that the apparent sudden increase in strength is due to machine inertia and does not reflect a real increase in the strength of the rocks. Taking inertia into account, the actual failure stresses of the three rocks are relatively independent of strain rate betweeen 10/sup -2/ and 10 sec/sup -1/. In the same interval, the strains at which the unconfined rocks begin to fragment tend to be lower at higher strain rates. The combination of decreasing strains and relatively constant stresses with increasing strain rate suggests that the energy necessary to fragment the unconfined rocks is lower at higher strain rates.

  15. Life Testing of the Vapor Compression Distillation/Urine Processing Assembly (VCD/UPA) at the Marshall Space Flight Center (1993 to 1997)

    NASA Technical Reports Server (NTRS)

    Wieland, P.; Hutchens, C.; Long, D.; Salyer, B.

    1998-01-01

    Wastewater and urine generated on the International Space Station will be processed to recover pure water using vapor compression distillation (VCD). To verify the long-term reliability and performance of the VCD Urine Processor Assembly (UPA), life testing was performed at the Marshall Space Flight Center (MSFC) from January 1993 to April 1996. Two UPA'S, the VCD-5 and VCD-5A, were tested for 204 days and 665 days, respectively. The compressor gears and the distillation centrifuge drive belt were found to have operating lives of approximately 4,800 hours, equivalent to 3.9 years of operation on ISS for a crew of three at an average processing rate of 1.76 kg/h (3.97 lb/h). Precise alignment of the flex-splines of the fluids and purge pump motor drives is essential to avoid premature failure after about 400 hours of operation. Results indicate that, with some design and procedural modifications and suitable quality control, the required performance and operational life can be met with the VCD/UPA.

  16. Charpy impact test results for low-activation ferritic alloys

    SciTech Connect

    Cannon, N.S.; Hu, W.L.; Gelles, D.S.

    1987-05-01

    The objective of this work is to evaluate the shift of the ductile to brittle transition temperature (DBTT) and the reduction of the upper shelf energy (USE) due to neutron irradiation of low activation ferritic alloys. Six low activation ferritic alloys have been tested following irradiation at 365/sup 0/C to 10 dpa and compared with control specimens in order to assess the effect of irradiation on Charpy impact properties.

  17. Compression and venous ulcers.

    PubMed

    Stücker, M; Link, K; Reich-Schupke, S; Altmeyer, P; Doerler, M

    2013-03-01

    Compression therapy is considered to be the most important conservative treatment of venous leg ulcers. Until a few years ago, compression bandages were regarded as first-line therapy of venous leg ulcers. However, to date medical compression stockings are the first choice of treatment. With respect to compression therapy of venous leg ulcers the following statements are widely accepted: 1. Compression improves the healing of ulcers when compared with no compression; 2. Multicomponent compression systems are more effective than single-component compression systems; 3. High compression is more effective than lower compression; 4. Medical compression stockings are more effective than compression with short stretch bandages. Healed venous leg ulcers show a high relapse rate without ongoing treatment. The use of medical stockings significantly reduces the amount of recurrent ulcers. Furthermore, the relapse rate of venous leg ulcers can be significantly reduced by a combination of compression therapy and surgery of varicose veins compared with compression therapy alone. PMID:23482538

  18. Testing a Theoretical Model of Immigration Transition and Physical Activity.

    PubMed

    Chang, Sun Ju; Im, Eun-Ok

    2015-01-01

    The purposes of the study were to develop a theoretical model to explain the relationships between immigration transition and midlife women's physical activity and test the relationships among the major variables of the model. A theoretical model, which was developed based on transitions theory and the midlife women's attitudes toward physical activity theory, consists of 4 major variables, including length of stay in the United States, country of birth, level of acculturation, and midlife women's physical activity. To test the theoretical model, a secondary analysis with data from 127 Hispanic women and 123 non-Hispanic (NH) Asian women in a national Internet study was used. Among the major variables of the model, length of stay in the United States was negatively associated with physical activity in Hispanic women. Level of acculturation in NH Asian women was positively correlated with women's physical activity. Country of birth and level of acculturation were significant factors that influenced physical activity in both Hispanic and NH Asian women. The findings support the theoretical model that was developed to examine relationships between immigration transition and physical activity; it shows that immigration transition can play an essential role in influencing health behaviors of immigrant populations in the United States. The NH theoretical model can be widely used in nursing practice and research that focus on immigrant women and their health behaviors. Health care providers need to consider the influences of immigration transition to promote immigrant women's physical activity. PMID:26502554

  19. Spacecraft Environmental Testing SMAP (Soil, Moisture, Active, Passive)

    NASA Technical Reports Server (NTRS)

    Fields, Keith

    2014-01-01

    Testing a complete full up spacecraft to verify it will survive the environment, in which it will be exposed to during its mission, is a formidable task in itself. However, the ''test like you fly'' philosophy sometimes gets compromised because of cost, design and or time. This paper describes the thermal-vacuum and mass properties testing of the Soil Moisture Active Passive (SMAP) earth orbiting satellite. SMAP will provide global observations of soil moisture and freeze/thaw state (the hydrosphere state). SMAP hydrosphere state measurements will be used to enhance understanding of processes that link the water, energy, and carbon cycles, and to extend the capabilities of weather and climate prediction models. It will explain the problems encountered, and the solutions developed, which minimized the risk typically associated with such an arduous process. Also discussed, the future of testing on expensive long lead-time spacecraft. Will we ever reach the ''build and shoot" scenario with minimal or no verification testing?

  20. Compressibility of solids

    NASA Technical Reports Server (NTRS)

    Vinet, P.; Ferrante, J.; Rose, J. H.; Smith, J. R.

    1987-01-01

    A universal form is proposed for the equation of state (EOS) of solids. Good agreement is found for a variety of test data. The form of the EOS is used to suggest a method of data analysis, which is applied to materials of geophysical interest. The isothermal bulk modulus is discussed as a function of the volume and of the pressure. The isothermal compression curves for materials of geophysical interest are examined.

  1. Compressive beamforming.

    PubMed

    Xenaki, Angeliki; Gerstoft, Peter; Mosegaard, Klaus

    2014-07-01

    Sound source localization with sensor arrays involves the estimation of the direction-of-arrival (DOA) from a limited number of observations. Compressive sensing (CS) solves such underdetermined problems achieving sparsity, thus improved resolution, and can be solved efficiently with convex optimization. The DOA estimation problem is formulated in the CS framework and it is shown that CS has superior performance compared to traditional DOA estimation methods especially under challenging scenarios such as coherent arrivals and single-snapshot data. An offset and resolution analysis is performed to indicate the limitations of CS. It is shown that the limitations are related to the beampattern, thus can be predicted. The high-resolution capabilities and the robustness of CS are demonstrated on experimental array data from ocean acoustic measurements for source tracking with single-snapshot data. PMID:24993212

  2. Microcalorimetric and manometric tests to assess anammox activity.

    PubMed

    Scaglione, D; Buttiglieri, G; Ficara, E; Caffaz, S; Lubello, C; Malpei, F

    2009-01-01

    The present study compares two experimental methods to evaluate Anammox activity based on the assessment of (1) the N(2) production rate by a manometric device, as previously proposed, and (2) the heat production rate by a microcalorimeter. Two samples of Anammox suspended biomass were taken from a pilot-plant, and their specific Anammox activity measured by both techniques. Both methods were successfully applied. As for calorimetric tests, they were performed for the first time on Anammox enriched sludge samples. Comparisons between the specific Anammox activities estimated by manometry and calorimetry and between expected (from the reaction enthalpy) and measured heat productions were performed. Promising results were obtained. PMID:19923777

  3. Activated carbon testing for the 200 area effluent treatment facility

    SciTech Connect

    Wagner, R.N.

    1997-01-17

    This report documents pilot and laboratory scale testing of activated carbon for use in the 200 Area Effluent Treatment Facility peroxide decomposer columns. Recommendations are made concerning column operating conditions and hardware design, the optimum type of carbon for use in the plant, and possible further studies.

  4. Hydrostatic, uniaxial, and triaxial compression tests on unpoled "Chem-prep" PZT 95/5-2Nb ceramic within temperature range of -55 to 75 degrees C.

    SciTech Connect

    Zeuch, David Henry; Montgomery, Stephen Tedford; Lee, Moo Yul; Hofer, John H.

    2003-10-01

    Sandia is currently developing a lead-zirconate-titanate ceramic 95/5-2Nb (or PNZT) from chemically prepared ('chem-prep') precursor powders. Previous PNZT ceramic was fabricated from the powders prepared using a 'mixed-oxide' process. The specimens of unpoled PNZT ceramic from batch HF803 were tested under hydrostatic, uniaxial, and constant stress difference loading conditions within the temperature range of -55 to 75 C and pressures to 500 MPa. The objective of this experimental study was to obtain mechanical properties and phase relationships so that the grain-scale modeling effort can develop and test its models and codes using realistic parameters. The stress-strain behavior of 'chem-prep' PNZT under different loading paths was found to be similar to that of 'mixed-oxide' PNZT. The phase transformation from ferroelectric to antiferroelectric occurs in unpoled ceramic with abrupt increase in volumetric strain of about 0.7 % when the maximum compressive stress, regardless of loading paths, equals the hydrostatic pressure at which the transformation otherwise takes place. The stress-volumetric strain relationship of the ceramic undergoing a phase transformation was analyzed quantitatively using a linear regression analysis. The pressure (P{sub T1}{sup H}) required for the onset of phase transformation with respect to temperature is represented by the best-fit line, P{sub T1}{sup H} (MPa) = 227 + 0.76 T (C). We also confirmed that increasing shear stress lowers the mean stress and the volumetric strain required to trigger phase transformation. At the lower bound (-55 C) of the tested temperature range, the phase transformation is permanent and irreversible. However, at the upper bound (75 C), the phase transformation is completely reversible as the stress causing phase transformation is removed.

  5. Lossy Compression of ACS images

    NASA Astrophysics Data System (ADS)

    Cox, Colin

    2004-01-01

    A method of compressing images stored as floating point arrays was proposed several years ago by White and Greenfield. With the increased image sizes encountered in the last few years and the consequent need to distribute large data volumes, the value of applying such a procedure has become more evident. Methods such as this which offer significant compression ratios are lossy and there is always some concern that statistically important information might be discarded. Several astronomical images have been analyzed and, in the examples tested, compression ratios of about six were obtained with no significant information loss.

  6. Advanced Vehicle Testing Activity: Hydrogen-Fueled Mercedes Sprinter Van Operating Summary - January 2003

    SciTech Connect

    Karner, D.; Francfort, J.E.

    2003-01-22

    Over the past two years, Arizona Public Service, a subsidiary of Pinnacle West Capital Corporation, in cooperation with the U.S. Department of Energy's Advanced Vehicle Testing Activity, tested four gaseous fuel vehicles as part of its alternative fueled vehicle fleet. One vehicle operated initially using compressed natural gas (CNG) and later a blend of CNG and hydrogen. Of the other three vehicles, one was fueled with pure hydrogen and two were fueled with a blend of CNG and hydrogen. The three blended-fuel vehicles were originally equipped with either factory CNG engines or factory gasoline engines that were converted to run CNG fuel. The vehicles were variously modified to operate on blended fuel and were tested using 15 to 50% blends of hydrogen (by volume). The pure-hydrogen-fueled vehicle was converted from gasoline fuel to operate on 100% hydrogen. All vehicles were fueled from the Arizona Public Service's Alternative Fuel Pilot Plant, which was developed to dispense gaseous fuels, including CNG, blends of CNG and hydrogen, and pure hydrogen with up to 99.9999% purity. The primary objective of the test was to evaluate the safety and reliability of operating vehicles on hydrogen and blended hydrogen fuel, and the interface between the vehicles and the hydrogen fueling infrastructure. A secondary objective was to quantify vehicle emissions, cost, and performance. Over a total of 40,000 fleet test miles, no safety issues were found. Also, significant reductions in emissions were achieved by adding hydrogen to the fuel. This report presents results of testing conducted over 6,864 kilometers (4,265 miles) of operation using the pure-hydrogen-fueled Mercedes Sprinter van.

  7. Advanced Vehicle Testing Activity: Dodge Ram Wagon Van - Hydrogen/CNG Operations Summary - January 2003

    SciTech Connect

    Karner, D.; Francfort, J.E.

    2003-01-16

    Over the past two years, Arizona Public Service, a subsidiary of Pinnacle West Capital Corporation, in cooperation with the U.S. Department of Energy's Advanced Vehicle Testing Activity, tested four gaseous fuel vehicles as part of its alternative fueled vehicle fleet. One vehicle, a Dodge Ram Wagon Van, operated initially using compressed natural gas (CNG) and later a blend of CNG and hydrogen. Of the other three vehicles, one was fueled with pure hydrogen and two were fueled with a blend of CNG and hydrogen. The three blended-fuel vehicles were originally equipped with either factory CNG engines or factory gasoline engines that were converted to run CNG fuel. The vehicles were variously modified to operate on blended fuel and were tested using 15 to 50% blends of hydrogen (by volume). The pure-hydrogen-fueled vehicle was converted from gasoline fuel to operate on 100% hydrogen. All vehicles were fueled from the Arizona Public Service's Fuel Pilot Plant, which was developed to dispense gaseous fuels, including CNG, blends of CNG and hydrogen, and pure hydrogen with up to 99.9999% purity. The primary objective of the test was to evaluate the safety and reliability of operating vehicles on hydrogen and blended hydrogen fuel, and the interface between the vehicles and the hydrogen fueling infrastructure. A secondary objective was to quantify vehicle emissions, cost, and performance. Over a total of 40,000 fleet test miles, no safety issues were found. Also, significant reductions in emissions were achieved by adding hydrogen to the fuel. This report presents results of 22,816 miles of testing for the Dodge Ram Wagon Van, operating on CNG fuel, and a blended fuel of 15% hydrogen-85% CNG.

  8. Advanced Vehicle Testing Activity: High-Percentage Hydrogen/CNG Blend, Ford F-150 -- Operating Summary

    SciTech Connect

    Don Karner; Francfort, James Edward

    2003-01-01

    Over the past two years, Arizona Public Service, a subsidiary of Pinnacle West Capital Corporation, in cooperation with the U.S. Department of Energy’s Advanced Vehicle Testing Activity, tested four gaseous fuel vehicles as part of its alternative fueled vehicle fleet. One vehicle operated initially using compressed natural gas (CNG) and later a blend of CNG and hydrogen. Of the other three vehicles, one was fueled with pure hydrogen and two were fueled with a blend of CNG and hydrogen. The three blended-fuel vehicles were originally equipped with either factory CNG engines or factory gasoline engines that were converted to run CNG fuel. The vehicles were variously modified to operate on blended fuel and were tested using 15 to 50% blends of hydrogen (by volume). The pure-hydrogen-fueled vehicle was converted from gasoline fuel to operate on 100% hydrogen. All vehicles were fueled from the Arizona Public Service’s Alternative Fuel Pilot Plant, which was developed to dispense gaseous fuels, including CNG, blends of CNG and hydrogen, and pure hydrogen with up to 99.9999% purity. The primary objective of the test was to evaluate the safety and reliability of operating vehicles on hydrogen and blended hydrogen fuel, and the interface between the vehicles and the hydrogen fueling infrastructure. A secondary objective was to quantify vehicle emissions, cost, and performance. Over a total of 40,000 fleet test miles, no safety issues were found. Also, significant reductions in emissions were achieved by adding hydrogen to the fuel. This report presents the results of 4,695 miles of testing for one of the blended fuel vehicles, a Ford F-150 pickup truck, operating on up to 50% hydrogen–50% CNG fuel.

  9. Advanced Vehicle Testing Activity: Dodge Ram Wagon Van -- Hydrogen/CNG Operations Summary

    SciTech Connect

    Don Karner; Francfort, James Edward

    2003-01-01

    Over the past two years, Arizona Public Service, a subsidiary of Pinnacle West Capital Corporation, in cooperation with the U.S. Department of Energy’s Advanced Vehicle Testing Activity, tested four gaseous fuel vehicles as part of its alternative fueled vehicle fleet. One vehicle, a Dodge Ram Wagon Van, operated initially using compressed natural gas (CNG) and later a blend of CNG and hydrogen. Of the other three vehicles, one was fueled with pure hydrogen and two were fueled with a blend of CNG and hydrogen. The three blended-fuel vehicles were originally equipped with either factory CNG engines or factory gasoline engines that were converted to run CNG fuel. The vehicles were variously modified to operate on blended fuel and were tested using 15 to 50% blends of hydrogen (by volume). The pure-hydrogen-fueled vehicle was converted from gasoline fuel to operate on 100% hydrogen. All vehicles were fueled from the Arizona Public Service’s Alternative Fuel Pilot Plant, which was developed to dispense gaseous fuels, including CNG, blends of CNG and hydrogen, and pure hydrogen with up to 99.9999% purity. The primary objective of the test was to evaluate the safety and reliability of operating vehicles on hydrogen and blended hydrogen fuel, and the interface between the vehicles and the hydrogen fueling infrastructure. A secondary objective was to quantify vehicle emissions, cost, and performance. Over a total of 40,000 fleet test miles, no safety issues were found. Also, significant reductions in emissions were achieved by adding hydrogen to the fuel. This report presents results of 22,816 miles of testing for the Dodge Ram Wagon Van, operating on CNG fuel, and a blended fuel of 15% hydrogen–85% CNG.

  10. Advanced Vehicle Testing Activity: Hydrogen-Fueled Mercedes Sprinter Van -- Operating Summary

    SciTech Connect

    Karner, D.; Francfort, James Edward

    2003-01-01

    Over the past two years, Arizona Public Service, a subsidiary of Pinnacle West Capital Corporation, in cooperation with the U.S. Department of Energy's Advanced Vehicle Testing Activity, tested four gaseous fuel vehicles as part of its alternative fueled vehicle fleet. One vehicle operated initially using compressed natural gas (CNG) and later a blend of CNG and hydrogen. Of the other three vehicles, one was fueled with pure hydrogen and two were fueled with a blend of CNG and hydrogen. The three blended-fuel vehicles were originally equipped with either factory CNG engines or factory gasoline engines that were converted to run CNG fuel. The vehicles were variously modified to operate on blended fuel and were tested using 15 to 50% blends of hydrogen (by volume). The pure- hydrogen-fueled vehicle was converted from gasoline fuel to operate on 100% hydrogen. All vehicles were fueled from the Arizona Public Service's Alternative Fuel Pilot Plant, which was developed to dispense gaseous fuels, including CNG, blends of CNG and hydrogen, and pure hydrogen with up to 99.9999% purity. The primary objective of the test was to evaluate the safety and reliability of operating vehicles on hydrogen and blended hydrogen fuel, and the interface between the vehicles and the hydrogen fueling infrastructure. A secondary objective was to quantify vehicle emissions, cost, and performance. Over a total of 40,000 fleet test miles, no safety issues were found. Also, significant reductions in emissions were achieved by adding hydrogen to the fuel. This report presents results of testing conducted over 6,864 kilometers (4,265 miles) of operation using the pure-hydrogen-fueled Mercedes Sprinter van.

  11. Advanced Vehicle Testing Activity: Low-Percentage Hydrogen/CNG Blend, Ford F-150 -- Operating Summary

    SciTech Connect

    Karner, D.; Francfort, James Edward

    2003-01-01

    Over the past two years, Arizona Public Service, a subsidiary of Pinnacle West Capital Corporation, in cooperation with the U.S. Department of Energy’s Advanced Vehicle Testing Activity, tested four gaseous fuel vehicles as part of its alternative fueled vehicle fleet. One vehicle operated initially using compressed natural gas (CNG) and later a blend of CNG and hydrogen. Of the other three vehicles, one was fueled with pure hydrogen and two were fueled with a blend of CNG and hydrogen. The three blended-fuel vehicles were originally equipped with either factory CNG engines or factory gasoline engines that were converted to run CNG fuel. The vehicles were variously modified to operate on blended fuel and were tested using 15 to 50% blends of hydrogen (by volume). The pure-hydrogen-fueled vehicle was converted from gasoline fuel to operate on 100% hydrogen. All vehicles were fueled from the Arizona Public Service’s Alternative Fuel Pilot Plant, which was developed to dispense gaseous fuels, including CNG, blends of CNG and hydrogen, and pure hydrogen with up to 99.9999% purity The primary objective of the test was to evaluate the safety and reliability of operating vehicles on hydrogen and blended hydrogen fuel, and the interface between the vehicles and the hydrogen fueling infrastructure. A secondary objective was to quantify vehicle emissions, cost, and performance. Over a total of 40,000 fleet test miles, no safety issues were found. Also, significant reductions in emissions were achieved by adding hydrogen to the fuel. This report presents results of 16,942 miles of testing for one of the blended fuel vehicles, a Ford F-150 pickup truck, operating on up to 30% hydrogen/70% CNG fuel.

  12. Nonpainful wide-area compression inhibits experimental pain

    PubMed Central

    Honigman, Liat; Bar-Bachar, Ofrit; Yarnitsky, David; Sprecher, Elliot; Granovsky, Yelena

    2016-01-01

    Abstract Compression therapy, a well-recognized treatment for lymphoedema and venous disorders, pressurizes limbs and generates massive non-noxious afferent sensory barrages. The aim of this study was to study whether such afferent activity has an analgesic effect when applied on the lower limbs, hypothesizing that larger compression areas will induce stronger analgesic effects, and whether this effect correlates with conditioned pain modulation (CPM). Thirty young healthy subjects received painful heat and pressure stimuli (47°C for 30 seconds, forearm; 300 kPa for 15 seconds, wrist) before and during 3 compression protocols of either SMALL (up to ankles), MEDIUM (up to knees), or LARGE (up to hips) compression areas. Conditioned pain modulation (heat pain conditioned by noxious cold water) was tested before and after each compression protocol. The LARGE protocol induced more analgesia for heat than the SMALL protocol (P < 0.001). The analgesic effect interacted with gender (P = 0.015). The LARGE protocol was more efficient for females, whereas the MEDIUM protocol was more efficient for males. Pressure pain was reduced by all protocols (P < 0.001) with no differences between protocols and no gender effect. Conditioned pain modulation was more efficient than the compression-induced analgesia. For the LARGE protocol, precompression CPM efficiency positively correlated with compression-induced analgesia. Large body area compression exerts an area-dependent analgesic effect on experimental pain stimuli. The observed correlation with pain inhibition in response to robust non-noxious sensory stimulation may suggest that compression therapy shares similar mechanisms with inhibitory pain modulation assessed through CPM. PMID:27152691

  13. Nonpainful wide-area compression inhibits experimental pain.

    PubMed

    Honigman, Liat; Bar-Bachar, Ofrit; Yarnitsky, David; Sprecher, Elliot; Granovsky, Yelena

    2016-09-01

    Compression therapy, a well-recognized treatment for lymphoedema and venous disorders, pressurizes limbs and generates massive non-noxious afferent sensory barrages. The aim of this study was to study whether such afferent activity has an analgesic effect when applied on the lower limbs, hypothesizing that larger compression areas will induce stronger analgesic effects, and whether this effect correlates with conditioned pain modulation (CPM). Thirty young healthy subjects received painful heat and pressure stimuli (47°C for 30 seconds, forearm; 300 kPa for 15 seconds, wrist) before and during 3 compression protocols of either SMALL (up to ankles), MEDIUM (up to knees), or LARGE (up to hips) compression areas. Conditioned pain modulation (heat pain conditioned by noxious cold water) was tested before and after each compression protocol. The LARGE protocol induced more analgesia for heat than the SMALL protocol (P < 0.001). The analgesic effect interacted with gender (P = 0.015). The LARGE protocol was more efficient for females, whereas the MEDIUM protocol was more efficient for males. Pressure pain was reduced by all protocols (P < 0.001) with no differences between protocols and no gender effect. Conditioned pain modulation was more efficient than the compression-induced analgesia. For the LARGE protocol, precompression CPM efficiency positively correlated with compression-induced analgesia. Large body area compression exerts an area-dependent analgesic effect on experimental pain stimuli. The observed correlation with pain inhibition in response to robust non-noxious sensory stimulation may suggest that compression therapy shares similar mechanisms with inhibitory pain modulation assessed through CPM. PMID:27152691

  14. Estimating JPEG2000 compression for image forensics using Benford's Law

    NASA Astrophysics Data System (ADS)

    Qadir, Ghulam; Zhao, Xi; Ho, Anthony T. S.

    2010-05-01

    With the tremendous growth and usage of digital images nowadays, the integrity and authenticity of digital content is becoming increasingly important, and a growing concern to many government and commercial sectors. Image Forensics, based on a passive statistical analysis of the image data only, is an alternative approach to the active embedding of data associated with Digital Watermarking. Benford's Law was first introduced to analyse the probability distribution of the 1st digit (1-9) numbers of natural data, and has since been applied to Accounting Forensics for detecting fraudulent income tax returns [9]. More recently, Benford's Law has been further applied to image processing and image forensics. For example, Fu et al. [5] proposed a Generalised Benford's Law technique for estimating the Quality Factor (QF) of JPEG compressed images. In our previous work, we proposed a framework incorporating the Generalised Benford's Law to accurately detect unknown JPEG compression rates of watermarked images in semi-fragile watermarking schemes. JPEG2000 (a relatively new image compression standard) offers higher compression rates and better image quality as compared to JPEG compression. In this paper, we propose the novel use of Benford's Law for estimating JPEG2000 compression for image forensics applications. By analysing the DWT coefficients and JPEG2000 compression on 1338 test images, the initial results indicate that the 1st digit probability of DWT coefficients follow the Benford's Law. The unknown JPEG2000 compression rates of the image can also be derived, and proved with the help of a divergence factor, which shows the deviation between the probabilities and Benford's Law. Based on 1338 test images, the mean divergence for DWT coefficients is approximately 0.0016, which is lower than DCT coefficients at 0.0034. However, the mean divergence for JPEG2000 images compression rate at 0.1 is 0.0108, which is much higher than uncompressed DWT coefficients. This result

  15. A review of DOE HEPA filter component test activities

    SciTech Connect

    Slawski, J.W.; Bresson, J.F.; Scripsick, R.C.

    1997-08-01

    All HEPA filters purchased for installation in DOE nuclear facilities are required to be tested at a Filter Test Facility (FTF) prior to installation. The number of HEPA filters purchased by DOE has been reduced so much that the Hanford FTF was closed. From Fiscal Year (FY) 1992 to 1994, funding was not provided to the FTF Technical Support Group (TSG) at the Los Alamos National Laboratory. As a consequence, Round Robin Tests (RRTs), performed twice each year by the FTFs to assess constituency of test results among the FTFs, were not performed in FY 1992 and FY 1993. The Annual Reports of FTF test activities were not prepared for FY 1992 - 1995. Technical support provided to the FTFs was minimal. There is talk of closing a second FTF, and ongoing discussions as to whether DOE will continue to fund operation of the FTFs. In FY 1994, DOE Defense Programs commenced funding the TSG. RRT data for FY 1994 and 1995 have been entered into the database; the FY 1994 RRT report has been issued; and the FY 1995 RRT report is in progress. Data from semiannual reports have been retrieved and entered into the database. Standards related to HEPA filter test and procurement activities are now scheduled for issuance by FY 1996. Continuation of these activities depends on whether DOE will continue to support the HEPA filter test program. The history and activities of the FTFs and the TSG at Los Alamos have been reported at previous Air Cleaning Conferences. Data from the FY 1991 Annual Report of FTF activities was presented at the 1992 Air Cleaning Conference. Preparation of the Annual Reports was temporarily suspended in 1992. However, all of the FTF Semiannual report data have been retrieved and entered into the data base. This paper focuses primarily on the results of HEPA filter tests conducted by FTFs during FY 1992 - FY 1995, and the possible effects of the DOE program uncertainties on the quality of HEPA filters for installation at the DOE sites. 15 refs., 13 tabs.

  16. Development of a Fast Breeder Reactor Fuel Bundle Deformation Analysis Code - BAMBOO: Development of a Pin Dispersion Model and Verification by the Out-of-Pile Compression Test

    SciTech Connect

    Uwaba, Tomoyuki; Ito, Masahiro; Ukai, Shigeharu

    2004-02-15

    To analyze the wire-wrapped fast breeder reactor fuel pin bundle deformation under bundle/duct interaction conditions, the Japan Nuclear Cycle Development Institute has developed the BAMBOO computer code. This code uses the three-dimensional beam element to calculate fuel pin bowing and cladding oval distortion as the primary deformation mechanisms in a fuel pin bundle. The pin dispersion, which is disarrangement of pins in a bundle and would occur during irradiation, was modeled in this code to evaluate its effect on bundle deformation. By applying the contact analysis method commonly used in the finite element method, this model considers the contact conditions at various axial positions as well as the nodal points and can analyze the irregular arrangement of fuel pins with the deviation of the wire configuration.The dispersion model was introduced in the BAMBOO code and verified by using the results of the out-of-pile compression test of the bundle, where the dispersion was caused by the deviation of the wire position. And the effect of the dispersion on the bundle deformation was evaluated based on the analysis results of the code.

  17. Microbiological test results of the environmental control and life support systems vapors compression distillation subsystem recycle tank components following various pretreatment protocols

    NASA Technical Reports Server (NTRS)

    Huff, Tim

    1993-01-01

    Microbiological samples were collected from the recycle tank of the vapor compression distillation (VCD) subsystem of the water recovery test at NASA MSFC following a 68-day run. The recycle tank collects rejected urine brine that was pretreated with a commercially available oxidant (Oxone) and sulfuric acid and pumps it back to the processing component of the VCD. Samples collected included a water sample and two swab samples, one from the particulate filter surface and a second from material floating on the surface of the water. No bacteria were recovered from the water sample. Both swab samples contained a spore-forming bacterium, Bacillus insolitus. A filamentous fungus was isolated from the floating material. Approximately 1 month after the pretreatment chemicals were changed to sodium hypochlorite and sulfuric acid, a swab of the particulate filter was again analyzed for microbial content. One fungus was isolated, and spore-forming bacteria were observed. These results indicate the inability of these pretreatments to inhibit surface attachment. The implications of the presence of these organisms are discussed.

  18. Oratest: a new concept to test caries activity.

    PubMed

    Saxena, S; Pundir, Siddharth; Aena, Jain

    2013-01-01

    Caries activity tests are based on the concept of a specific odontogenic infection, the principle causative organism being streptococci mutans. Their predominance is attributed to its acidogenic and aciduric nature after a selective growth advantages over the other non- acid tolerant organisms. Many studies on caries activity are aimed at finding relevant microorganisms. Till date, the ideal method to evaluate in terms of sensitivity, specialization and reliability has not been found. Many of these caries activity tests require extensive work up time and additional equipment. Rosenberg et al. in 1989 developed Oratest, a simple, economical, non- invasive and less time-consuming test for estimating the oral microbial level. The test is simple and consists of rinsing the mouth with 10 ml of sterile milk, 3 ml of which is mixed with 0.12 ml of 0.1% methylene blue dye and observed for colour change. The present study sample consists of twenty five children with dental caries and twenty five controls, free of caries, gingivitis and other oral ailments. This study is being conducted in the department of Oral Pathology & Microbiology and is in the preliminary phase so further results are awaited. PMID:23727739

  19. The active flexible wing aeroservoelastic wind-tunnel test program

    NASA Technical Reports Server (NTRS)

    Noll, Thomas; Perry, Boyd

    1989-01-01

    For a specific application of aeroservoelastic technology, Rockwell International Corporation developed a concept known as the Active Flexible Wing (AFW). The concept incorporates multiple active leading-and trailing-edge control surfaces with a very flexible wing such that wing shape is varied in an optimum manner resulting in improved performance and reduced weight. As a result of a cooperative program between the AFWAL's Flight Dynamics Laboratory, Rockwell, and NASA LaRC, a scaled aeroelastic wind-tunnel model of an advanced fighter was designed, fabricated, and tested in the NASA LaRC Transonic Dynamics Tunnel (TDT) to validate the AFW concept. Besides conducting the wind-tunnel tests NASA provided a design of an Active Roll Control (ARC) System that was implemented and evaluated during the tests. The ARC system used a concept referred to as Control Law Parameterization which involves maintaining constant performance, robustness, and stability while using different combinations of multiple control surface displacements. Since the ARC system used measured control surface stability derivatives during the design, the predicted performance and stability results correlated very well with test measurements.

  20. Shuttle active thermal control system development testing. Volume 5: Integrated radiator/expendable cooling system tests

    NASA Technical Reports Server (NTRS)

    Scheps, P. B.

    1974-01-01

    Tests were conducted to gather data on a space shuttle active control system (ATCS) incorporating both radiators and an expendable cooling device to provide vehicle heat removal. Two systems were tested and design information was provided for both nominal and limit conditions. The tests verified the concept that an integrated radiator/expendable cooling system can adequately maintain desired water quantities while responding to variations in heat loads and environments. In addition, the need for duct heating was demonstrated, while exhaust nozzle heating was also shown to be unnecessary.

  1. Compressive sensing exploiting wavelet-domain dependencies for ECG compression

    NASA Astrophysics Data System (ADS)

    Polania, Luisa F.; Carrillo, Rafael E.; Blanco-Velasco, Manuel; Barner, Kenneth E.

    2012-06-01

    Compressive sensing (CS) is an emerging signal processing paradigm that enables sub-Nyquist sampling of sparse signals. Extensive previous work has exploited the sparse representation of ECG signals in compression applications. In this paper, we propose the use of wavelet domain dependencies to further reduce the number of samples in compressive sensing-based ECG compression while decreasing the computational complexity. R wave events manifest themselves as chains of large coefficients propagating across scales to form a connected subtree of the wavelet coefficient tree. We show that the incorporation of this connectedness as additional prior information into a modified version of the CoSaMP algorithm can significantly reduce the required number of samples to achieve good quality in the reconstruction. This approach also allows more control over the ECG signal reconstruction, in particular, the QRS complex, which is typically distorted when prior information is not included in the recovery. The compression algorithm was tested upon records selected from the MIT-BIH arrhythmia database. Simulation results show that the proposed algorithm leads to high compression ratios associated with low distortion levels relative to state-of-the-art compression algorithms.

  2. Tests of a mixed compression axisymmetric inlet with large transonic mass flow at Mach numbers 0.6 to 2.65

    NASA Technical Reports Server (NTRS)

    Smeltzer, D. B.; Sorensen, N. E.

    1972-01-01

    A 38.8-cm (15.28-in.) capture diameter model of a mixed-compression axisymmetric inlet system with a translating cowl was designed and tested. The internal contours, designed for Mach number 2.65, provided a throat area of 59 percent of the capture area when the cowl was retracted for transonic operation. Other model features included a boundary-layer removal system, vortex generators, an engine airflow bypass system, cowl support struts, and rotating rakes at the engine face. All tunnel testing was conducted at a tunnel total pressure of about 1 atm (a unit Reynolds number of about 8.53 million/m at Mach number 2.65) at angles of attack from 0 deg to 4 deg. Results for the following were obtained: total-pressure recovery and distortion at the engine face as a function of bleed mass-flow ratio, the effect of bleed and vortex generator configurations on pressure recovery and distortion, inlet tolerance to unstart due to changes in angle of attack or Mach number, surface pressure distributions, boundary-layer profiles, and transonic additive drag. At Mach number 2.65 and with the best bleed configurations, maximum total pressure recovery at the engine face ranged from 91 to 94.5 percent with bleed mass-flow ratios from 4 to 9 percent, respectively, and total-pressure distortion was less than 10 percent. At off-design supersonic Mach numbers above 1.70, maximum total-pressure recoveries and corresponding bleed mass flows were about the same as at Mach number 2.65, with about 10 to 15 percent distortion. In the transonic Mach number range, total pressure recovery was high (above 96 percent) and distortion was low (less than 15 percent) only when the inlet mass-flow ration was reduced 0.02 to 0.06 from the maximum theoretical value (0.590 at Mach number 1.0).

  3. The Activity of Antimicrobial Surfaces Varies by Testing Protocol Utilized

    PubMed Central

    Campos, Matias D.; Zucchi, Paola C.; Phung, Ann; Leonard, Steven N.; Hirsch, Elizabeth B.

    2016-01-01

    Background Contaminated hospital surfaces are an important source of nosocomial infections. A major obstacle in marketing antimicrobial surfaces is a lack of efficacy data based on standardized testing protocols. Aim We compared the efficacy of multiple testing protocols against several “antimicrobial” film surfaces. Methods Four clinical isolates were used: one Escherichia coli, one Klebsiella pneumoniae, and two Staphylococcus aureus strains. Two industry methods (modified ISO 22196 and ASTM E2149), a “dried droplet”, and a “transfer” method were tested against two commercially available antimicrobial films, one film in development, an untreated control, and a positive (silver) control film. At 2 (only ISO) and 24 hours following inoculation, bacteria were collected from film surfaces and enumerated. Results Compared to untreated films in all protocols, there were no significant differences in recovery on either commercial brand at 2 or 24 hours after inoculation. The silver surface demonstrated significant microbicidal activity (mean loss 4.9 Log10 CFU/ml) in all methods and time points with the exception of 2 hours in the ISO protocol and the transfer method. Using our novel droplet method, no differences between placebo and active surfaces were detected. The surface in development demonstrated variable activity depending on method, organism, and time point. The ISO demonstrated minimal activity at 2 hours but significant activity at 24 hours (mean 4.5 Log10 CFU/ml difference versus placebo). The ASTEM protocol exhibited significant differences in recovery of staphylococci (mean 5 Log10 CFU/ml) but not Gram-negative isolates (10 fold decrease). Minimal activity was observed with this film in the transfer method. Conclusions Varying results between protocols suggested that efficacy of antimicrobial surfaces cannot be easily and reproducibly compared. Clinical use should be considered and further development of representative methods is needed. PMID

  4. Taming Test Anxiety: The Activation of Failure-Related Concepts Enhances Cognitive Test Performance of Test-Anxious Students

    ERIC Educational Resources Information Center

    Tempel, Tobias; Neumann, Roland

    2016-01-01

    We investigated processes underlying performance decrements of highly test-anxious persons. Three experiments contrasted conditions that differed in the degree of activation of concepts related to failure. Participants memorized a list of words either containing words related to failure or containing no words related to failure in Experiment 1. In…

  5. Relaxation training affects success and activation on a teaching test.

    PubMed

    Helin, P; Hänninen, O

    1987-12-01

    We studied the effects of an audiocassette-relaxation training period (ART) and its timing on success at a teaching test (lecture type), on observed tension and on a number of physiological responses. The electrical activity of the upper trapezius muscle (EMG), heart rate (HR) and blood pressure (BP), of female and male instructor candidates, were examined before, during and after the teaching test as well as during its critique. The relaxation period (18 min) was presented either on the preceding night (ARTnt) or immediately before the teaching test (ARTimm). The influence of personality (types A-B and extrovert-introvert) was also studied. ART improved success at the teaching test in both sexes. In males (but not in females), ARTimm decreased EMG level during the test, but ARTnt increased EMG at the test period as compared to the control group. In females, both ARTnt and ARTimm lowered HR more than in the control group. ARTimm lowered systolic BP in both sexes. Personality types affected the ART responses; ART was more beneficial for type A than B subjects. PMID:3325481

  6. Wind Tunnel Test of the SMART Active Flap Rotor

    NASA Technical Reports Server (NTRS)

    Straub, Friedrich K.; Anand, Vaidyanthan R.; Birchette, Terrence S.; Lau, Benton H.

    2009-01-01

    Boeing and a team from Air Force, NASA, Army, DARPA, MIT, UCLA, and U. of Maryland have successfully completed a wind-tunnel test of the smart material actuated rotor technology (SMART) rotor in the 40- by 80-foot wind-tunnel of the National Full-Scale Aerodynamic Complex at NASA Ames Research Center. The Boeing SMART rotor is a full-scale, five-bladed bearingless MD 900 helicopter rotor modified with a piezoelectric-actuated trailing edge flap on each blade. The eleven-week test program evaluated the forward flight characteristics of the active-flap rotor at speeds up to 155 knots, gathered data to validate state-of-the-art codes for rotor aero-acoustic analysis, and quantified the effects of open and closed loop active flap control on rotor loads, noise, and performance. The test demonstrated on-blade smart material control of flaps on a full-scale rotor for the first time in a wind tunnel. The effectiveness of the active flap control on noise and vibration was conclusively demonstrated. Results showed significant reductions up to 6dB in blade-vortex-interaction and in-plane noise, as well as reductions in vibratory hub loads up to 80%. Trailing-edge flap deflections were controlled within 0.1 degrees of the commanded value. The impact of the active flap on control power, rotor smoothing, and performance was also demonstrated. Finally, the reliability of the flap actuation system was successfully proven in more than 60 hours of wind-tunnel testing.

  7. Use of modified Fraser's stain in Promoting Activity Test (PAT).

    PubMed

    Borràs, M

    1988-09-01

    The Promoting Activity Test (PAT) requires a staining procedure that allows rapid, accurate and reliable counting of mitotic figures. We propose use of Fraser's kernechtrot-crystal violet technique, but eliminating the picric-alcoholic differentiation to avoid fading. This modified protocol gives higher mitotic counts in adult mouse adrenal cortex than the hematoxylin-eosin originally used, especially with respect to less conspicuous prophases. PMID:2464217

  8. Ambient temperature fatigue tests of elements of an actively cooled honeycomb sandwich structural panel

    NASA Technical Reports Server (NTRS)

    Sharpe, E. L.; Elber, W.

    1977-01-01

    Elements of an actively cooled structural panel for a hypersonic aircraft have been investigated for fatigue characteristics. The study involved a bonded honeycomb sandwich panel with d-shaped coolant tubes. The curved portion of these tubes was embedded in the honeycomb, and the flat portion was bonded or soldered to the inner surface of the outer skin. The elements examined were two plain skin specimens (aluminum alloy); two specimens with skins attached to manifolds and tubes (one specimen was bonded, the other soldered); and a specimen representative of a corner section of the complete cooled sandwich. Sinusoidal loads were applied to all specimens. The honeycomb sandwich specimen was loaded in both tension and compression; the other specimens were loaded in tension only. The cooling tubes were pressurized with oil throughout the fatigue tests. The most significant results of these tests follow: All specimens exceeded their design life of 20,000 cycles without damage. Crack growth rates obtained in the plain skin specimens were used to determine the crack growth characteristics of aluminum alloy. Cracks in skins either bonded or soldered to cooling tubes propagated past the tubes without penetration. The coolant tubes served as crack arresters and temporarily stopped crack growth when a crack reached a tube-skin interface. The honeycomb core demonstrated that it could contain leakage from a tube.

  9. Preference as a Function of Active Interresponse Times: A Test of the Active Time Model

    ERIC Educational Resources Information Center

    Misak, Paul; Cleaveland, J. Mark

    2011-01-01

    In this article, we describe a test of the active time model for concurrent variable interval (VI) choice. The active time model (ATM) suggests that the time since the most recent response is one of the variables controlling choice in concurrent VI VI schedules of reinforcement. In our experiment, pigeons were trained in a multiple concurrent…

  10. The Angiotensin Infusion Test and Peripheral Venous Renin Activity

    PubMed Central

    Silah, J. G.; Strong, C. G.; Nowaczynski, W.; Genest, J.

    1967-01-01

    Forty hypertensive patients were studied to examine the assumption that the angiotensin pressor dose reflects endogenous renin activity. Peripheral renin activity was assayed by the method of Boucher et al.4 Sensitivity to the infusion of synthetic angiotensin II was determined as suggested by Kaplan and Silah.1 Sixteen patients with essential hypertension with normal renal angiography required 3.8 ng. angiotensin/kg./min. to raise the diastolic pressure 20 mm. Hg. All but one were sensitive to angiotensin infusion of less than 5 ng./kg./min. Renin activity was normal in all except in one sensitive subject. Angiotensin infusion response and mean renin activity in 13 patients with essential hypertension with abnormal renal angiography were similar to that of the first group. The pressor dose in 11 renovascular hypertensives was 9.8 ng./kg./min. All but three had elevated plasma renin activity. Our results suggest that: (1) the angiotensin infusion test is suitable for differentiating patients with true renovascular hypertension from those with essential hypertension with or without associated renal artery disease; (2) the angiotensin pressor dose correlates with the level of peripheral venous renin activity (p < 0.01). PMID:4290836

  11. The angiotensin infusion test and peripheral venous renin activity.

    PubMed

    Silah, J G; Strong, C G; Nowaczynski, W; Genest, J

    1967-05-27

    Forty hypertensive patients were studied to examine the assumption that the angiotensin pressor dose reflects endogenous renin activity. Peripheral renin activity was assayed by the method of Boucher et al.(4) Sensitivity to the infusion of synthetic angiotensin II was determined as suggested by Kaplan and Silah.(1)Sixteen patients with essential hypertension with normal renal angiography required 3.8 ng. angiotensin/kg./min. to raise the diastolic pressure 20 mm. Hg. All but one were sensitive to angiotensin infusion of less than 5 ng./kg./min. Renin activity was normal in all except in one sensitive subject. Angiotensin infusion response and mean renin activity in 13 patients with essential hypertension with abnormal renal angiography were similar to that of the first group. The pressor dose in 11 renovascular hypertensives was 9.8 ng./kg./min. All but three had elevated plasma renin activity.OUR RESULTS SUGGEST THAT: (1) the angiotensin infusion test is suitable for differentiating patients with true renovascular hypertension from those with essential hypertension with or without associated renal artery disease; (2) the angiotensin pressor dose correlates with the level of peripheral venous renin activity (p < 0.01). PMID:4290836

  12. Honey shows potent inhibitory activity against the bovine testes hyaluronidase.

    PubMed

    Kolayli, Sevgi; Sahin, Huseyin; Can, Zehra; Yildiz, Oktay; Sahin, Kübra

    2016-08-01

    The purpose of this study was to investigate the anti-hyaluronidase activities of honeys from different botanical origins honeys in order to determine their anti-inflammatory properties. The total phenolic contents, total flavonoids and total tannin levels of six types of honey, chestnut, oak, heather, pine, buckwheat and mixed blossom, were determined. Concentration-related inhibition values were tested turbidimetrically on bovine testis hyaluronidase (BTHase) as IC50 (mg/mL). All honeys exhibited various concentration-dependent degrees of inhibition against BTHase. Inhibition values varied significantly depending on honeys' levels of phenolic contents, flavonoid and tannin. The honeys with the highest anti-hyaluronidase activity were oak, chestnut and heather. In conclusion, polyphenol-rich honeys have high anti-hyaluronidase activity, and these honeys have high protective and complementary potential against hyaluronidase-induced anti-inflammatory failures. PMID:26076195

  13. Micromechanics of composite laminate compression failure

    NASA Technical Reports Server (NTRS)

    Guynn, E. Gail; Bradley, Walter L.

    1986-01-01

    The Dugdale analysis for metals loaded in tension was adapted to model the failure of notched composite laminates loaded in compression. Compression testing details, MTS alignment verification, and equipment needs were resolved. Thus far, only 2 ductile material systems, HST7 and F155, were selected for study. A Wild M8 Zoom Stereomicroscope and necessary attachments for video taping and 35 mm pictures were purchased. Currently, this compression test system is fully operational. A specimen is loaded in compression, and load vs shear-crippling zone size is monitored and recorded. Data from initial compression tests indicate that the Dugdale model does not accurately predict the load vs damage zone size relationship of notched composite specimens loaded in compression.

  14. Kinetic theory of plasma adiabatic major radius compression in tokamaks

    NASA Astrophysics Data System (ADS)

    Gorelenkova, M. V.; Gorelenkov, N. N.; Azizov, E. A.; Romannikov, A. N.; Herrmann, H. W.

    1998-05-01

    In order to understand the individual charged particle behavior as well as plasma macroparameters (temperature, density, etc.) during the adiabatic major radius compression (R-compression) in a tokamak, a kinetic approach is used. The perpendicular electric field from the Ohm's law at zero resistivity is made use of in order to describe particle motion during the R-compression. Expressions for both passing and trapped particle energy and pitch angle change are derived for a plasma with high aspect ratio and circular magnetic surfaces. The particle behavior near the passing trapped boundary during the compression is studied to simulate the compression-induced collisional losses of alpha particles. Qualitative agreement is obtained with the alphas loss measurements in deuterium-tritium (D-T) experiments in the Tokamak Fusion Test Reactor (TFTR) [World Survey of Activities in Controlled Fusion Research [Nucl. Fusion special supplement (1991)] (International Atomic Energy Agency, Vienna, 1991)]. The plasma macroparameters evolution at the R-compression is calculated by solving the gyroaveraged drift kinetic equation.

  15. First Test of Fan Active Noise Control (ANC) Completed

    NASA Technical Reports Server (NTRS)

    2005-01-01

    With the advent of ultrahigh-bypass engines, the space available for passive acoustic treatment is becoming more limited, whereas noise regulations are becoming more stringent. Active noise control (ANC) holds promise as a solution to this problem. It uses secondary (added) noise sources to reduce or eliminate the offending noise radiation. The first active noise control test on the low-speed fan test bed was a General Electric Company system designed to control either the exhaust or inlet fan tone. This system consists of a "ring source," an induct array of error microphones, and a control computer. Fan tone noise propagates in a duct in the form of spinning waves. These waves are detected by the microphone array, and the computer identifies their spinning structure. The computer then controls the "ring source" to generate waves that have the same spinning structure and amplitude, but 180 out of phase with the fan noise. This computer generated tone cancels the fan tone before it radiates from the duct and is heard in the far field. The "ring source" used in these tests is a cylindrical array of 16 flat-plate acoustic radiators that are driven by thin piezoceramic sheets bonded to their back surfaces. The resulting source can produce spinning waves up to mode 7 at levels high enough to cancel the fan tone. The control software is flexible enough to work on spinning mode orders from -6 to 6. In this test, the fan was configured to produce a tone of order 6. The complete modal (spinning and radial) structure of the tones was measured with two builtin sets of rotating microphone rakes. These rakes provide a measurement of the system performance independent from the control system error microphones. In addition, the far-field noise was measured with a semicircular array of 28 microphones. This test represents the first in a series of tests that demonstrate different active noise control concepts, each on a progressively more complicated modal structure. The tests are

  16. SOFIA Telescope Functional Integration and Performance Test Activities

    NASA Astrophysics Data System (ADS)

    Waddell, P.; Haas, M. R.; Dunham, E. W.; Bremers, E.; Harms, F.; Keas, P. J.; Lattner, K.; Lillienthal, D.; Meyer, A. W.; Wolf, J.

    2004-12-01

    The Stratospheric Observatory for Infrared Astronomy (SOFIA) is a 2.7-m telescope installed in a Boeing 747SP. Collaborators developing the SOFIA telescope and observatory completed an intense period of activation between mid-June and mid-August, 2004. The integration activities included a preliminary modal survey; alignment of the Wide Field, Fine Field, and Focal Plane Imagers; installation of the secondary and tertiary mirrors; and their alignment relative to the primary mirror. Once these preliminaries were completed, SOFIA was rolled out of its hangar for a series of ground-based, on-sky tests using HIPO, the first science instrument to be installed on the telescope. First light was achieved observing Polaris on August 18, 2004. The on-sky test period encompassed 12 nights in late August and early September and included telescope step function response and first-order pointing control, image quality and optical tracking stability measurements, evaluation of the tracking imagers, gravity deformation studies, gyro alignment and bias rate measurement and correction, and performance tests of the secondary mirror Focus Centering Mechanism and Tilt Chopping Mechanism. It also included tests of the complete telescope command set, including Image Quality Compensation (IQC), quasi-static Flexible Body Compensation (FBC), reference frame transformations and trajectory estimation algorithms. This poster summarizes the results and describes the expected performance of SOFIA at the start of science observations. SOFIA is jointly funded by NASA and DLR and is managed by USRA and DSI. The successful, on-schedule completion of these tests involved close coordination by these three parties, CSA Engineering, CSEM, Kayser-Threde, L-3 Communications, Lowell Observatory, MAN-Technologies, Orbital Sciences, and others.

  17. Active Matrix Organic Light Emitting Diode (AMOLED) Environmental Test Report

    NASA Technical Reports Server (NTRS)

    Salazar, George A.

    2013-01-01

    This report focuses on the limited environmental testing of the AMOLED display performed as an engineering evaluation by The NASA Johnson Space Center (JSC)-specifically. EMI. Thermal Vac, and radiation tests. The AMOLED display is an active-matrix Organic Light Emitting Diode (OLED) technology. The testing provided an initial understanding of the technology and its suitability for space applications. Relative to light emitting diode (LED) displays or liquid crystal displays (LCDs), AMOLED displays provide a superior viewing experience even though they are much lighter and smaller, produce higher contrast ratio and richer colors, and require less power to operate than LCDs. However, AMOLED technology has not been demonstrated in a space environment. Therefore, some risks with the technology must be addressed before they can be seriously considered for human spaceflight. The environmental tests provided preliminary performance data on the ability of the display technology to handle some of the simulated induced space/spacecraft environments that an AMOLED display will see during a spacecraft certification test program. This engineering evaluation is part of a Space Act Agreement (SM) between The NASA/JSC and Honeywell International (HI) as a collaborative effort to evaluate the potential use of AMOLED technology for future human spaceflight missions- both government-led and commercial. Under this SM, HI is responsible for doing optical performance evaluation, as well as temperature and touch screen studies. The NASA/JSC is responsible for performing environmental testing comprised of EMI, Thermal Vac, and radiation tests. Additionally, as part of the testing, limited optical data was acquired to assess performance as the display was subjected to the induced environments. The NASA will benefit from this engineering evaluation by understanding AMOLED suitability for future use in space as well as becoming a smarter buyer (or developer) of the technology. HI benefits

  18. Compressed gas fuel storage system

    SciTech Connect

    Wozniak, John J.; Tiller, Dale B.; Wienhold, Paul D.; Hildebrand, Richard J.

    2001-01-01

    A compressed gas vehicle fuel storage system comprised of a plurality of compressed gas pressure cells supported by shock-absorbing foam positioned within a shape-conforming container. The container is dimensioned relative to the compressed gas pressure cells whereby a radial air gap surrounds each compressed gas pressure cell. The radial air gap allows pressure-induced expansion of the pressure cells without resulting in the application of pressure to adjacent pressure cells or physical pressure to the container. The pressure cells are interconnected by a gas control assembly including a thermally activated pressure relief device, a manual safety shut-off valve, and means for connecting the fuel storage system to a vehicle power source and a refueling adapter. The gas control assembly is enclosed by a protective cover attached to the container. The system is attached to the vehicle with straps to enable the chassis to deform as intended in a high-speed collision.

  19. Activated carbon passes tests for acid-gas cleanup

    SciTech Connect

    Harruff, L.G.; Bushkuhl, S.J.

    1996-06-24

    Use of activated carbon to remove hydrocarbon contaminants from the acid-gas feed to Claus sulfur-recovery units has been successfully pilot tested in Saudi Arabia. Pilot plant results are discussed here along with issues involved in scale-up to commercial size. Heavy hydrocarbons, particularly benzene, toluene, and xylene (BTX) have been linked to coke formation and catalyst deactivation in Claus converters. This deactivation results in reduced sulfur recovery and increased sulfur emissions from these plants. This clean-up process was proven to be capable of removing 95% of the BTX and other C{sub 6}+s from acid gas over a wide range of actual plant conditions. Following the adsorption step, the activated carbon was easily regenerated by use of low-pressure steam. A post-regeneration drying step using plant fuel gas also proved beneficial. The paper discusses feed contaminants, vapor-phase cleanup, testing design, test parameters and results, bed drying after regeneration, regeneration conditions, basic flow, system control, and full-scale installation.

  20. Active Blade Vibration Control Being Developed and Tested

    NASA Technical Reports Server (NTRS)

    Johnson, Dexter

    2003-01-01

    Gas turbine engines are currently being designed to have increased performance, lower weight and manufacturing costs, and higher reliability. Consequently, turbomachinery components, such as turbine and compressor blades, have designs that are susceptible to new vibration problems and eventual in-service failure due to high-cycle fatigue. To address this problem, researchers at the NASA Glenn Research Center are developing and testing innovative active blade vibration control concepts. Preliminary results of using an active blade vibration control system, involving a rotor supported by an active magnetic bearing in Glenn's Dynamic Spin Rig, indicate promising results (see the photograph). Active blade vibration control was achieved using feedback of blade strain gauge signals within the magnetic bearing control loop. The vibration amplitude was reduced substantially (see the graphs). Also, vibration amplitude amplification was demonstrated; this could be used to enhance structural mode identification, if desired. These results were for a nonrotating two-bladed disk. Tests for rotating blades are planned. Current and future active blade vibration control research is planned to use a fully magnetically suspended rotor and smart materials. For the fully magnetically suspended rotor work, three magnetic bearings (two radial and one axial) will be used as actuators instead of one magnetic bearing. This will allow additional degrees of freedom to be used for control. For the smart materials work, control effectors located on and off the blade will be considered. Piezoelectric materials will be considered for on-the-blade actuation, and actuator placement on a stator vane, or other nearby structure, will be investigated for off-the-blade actuation. Initial work will focus on determining the feasibility of these methods by performing basic analysis and simple experiments involving feedback control.

  1. Antiparasitic activity of parbendazole in critical tests in horses.

    PubMed

    Lyons, E T; Drudge, J H; Tolliver, S C

    1980-01-01

    Critical tests were conducted in 11 naturally infected horses to evaluate the anthelmintic activity of parbendazole. Single doses at the rates of 30, 20, 10, 5, or 2.5 mg/kg of body weight were administered by stomach tube to 1, 4, 2, 2, and 2 horses, respectively. Parbendazole was active against Parascaris equorum, Oxyuris equi, Strongylus vulgaris, Strongylus edentatus, and small strongyles throughout the range of doses. Generally, small numbers of P equorum were present, but apparently a dose rate higher than 2.5 mg/kg is necessary for complete clearance. Removal of O equi was virtually 100%, even at the 2.5 mg/kg dose rate, although mature forms were present in small numbers. Removal of S vulgaris and S edentatus was 98% to 100% at the largest and smallest dose rates and was somewhat inconsistent, especially of S edentatus, at most intermediate dose rates. Overall removal of small strongyles was good even at smallest dose rate. Activity was limited or lacking against stomach parasites. Transient diarrhea was observed for 24 to 48 hours after treatment at each dose rate tested. PMID:6892671

  2. Turbulence in Compressible Flows

    NASA Technical Reports Server (NTRS)

    1997-01-01

    Lecture notes for the AGARD Fluid Dynamics Panel (FDP) Special Course on 'Turbulence in Compressible Flows' have been assembled in this report. The following topics were covered: Compressible Turbulent Boundary Layers, Compressible Turbulent Free Shear Layers, Turbulent Combustion, DNS/LES and RANS Simulations of Compressible Turbulent Flows, and Case Studies of Applications of Turbulence Models in Aerospace.

  3. Information Technology Measurement and Testing Activities at NIST

    PubMed Central

    Hogan, Michael D.; Carnahan, Lisa J.; Carpenter, Robert J.; Flater, David W.; Fowler, James E.; Frechette, Simon P.; Gray, Martha M.; Johnson, L. Arnold; McCabe, R. Michael; Montgomery, Douglas; Radack, Shirley M.; Rosenthal, Robert; Shakarji, Craig M.

    2001-01-01

    Our high technology society continues to rely more and more upon sophisticated measurements, technical standards, and associated testing activities. This was true for the industrial society of the 20th century and remains true for the information society of the 21st century. Over the last half of the 20th century, information technology (IT) has been a powerful agent of change in almost every sector of the economy. The complexity and rapidly changing nature of IT have presented unique technical challenges to the National Institute of Standards and Technology (NIST) and to the scientific measurement community in developing a sound measurement and testing infrastructure for IT. This measurement and testing infrastructure for the important non-physical and non-chemical properties associated with complex IT systems is still in an early stage of development. This paper explains key terms and concepts of IT metrology, briefly reviews the history of the National Bureau of Standards/National Institute of Standards and Technology (NBS/NIST) in the field of IT, and reviews NIST’s current capabilities and work in measurement and testing for IT. It concludes with a look at what is likely to occur in the field of IT over the next ten years and what metrology roles NIST is likely to play. PMID:27500026

  4. Boron-10 ABUNCL Prototype Models And Initial Active Testing

    SciTech Connect

    Kouzes, Richard T.; Ely, James H.; Lintereur, Azaree T.; Siciliano, Edward R.

    2013-04-23

    The Department of Energy Office of Nuclear Safeguards and Security (NA-241) is supporting the project Coincidence Counting With Boron-Based Alternative Neutron Detection Technology at Pacific Northwest National Laboratory (PNNL) for the development of a 3He proportional counter alternative neutron coincidence counter. The goal of this project is to design, build and demonstrate a system based upon 10B-lined proportional tubes in a configuration typical for 3He-based coincidence counter applications. This report provides results from MCNPX model simulations and initial testing of the active mode variation of the Alternative Boron-Based Uranium Neutron Coincidence Collar (ABUNCL) design built by General Electric Reuter-Stokes. Initial experimental testing of the as-delivered passive ABUNCL was previously reported.

  5. Uranium Adsorption on Granular Activated Carbon – Batch Testing

    SciTech Connect

    Parker, Kent E.; Golovich, Elizabeth C.; Wellman, Dawn M.

    2013-09-01

    The uranium adsorption performance of two activated carbon samples (Tusaar Lot B-64, Tusaar ER2-189A) was tested using unadjusted source water from well 299-W19-36. These batch tests support ongoing performance optimization efforts to use the best material for uranium treatment in the Hanford Site 200 West Area groundwater pump-and-treat system. A linear response of uranium loading as a function of the solution-to-solid ratio was observed for both materials. Kd values ranged from ~380,000 to >1,900,000 ml/g for the B-64 material and ~200,000 to >1,900,000 ml/g for the ER2-189A material. Uranium loading values ranged from 10.4 to 41.6 μg/g for the two Tusaar materials.

  6. Utilisation of Wearable Computing for Space Programmes Test Activities Optimasation

    NASA Astrophysics Data System (ADS)

    Basso, V.; Lazzari, D.; Alemanni, M.

    2004-08-01

    New technologies are assuming a relevant importance in the Space business domain also in the Assembly Integration and Test (AIT) activities allowing process optimization and capability that were unthinkable only few years ago. This paper has the aim to describe Alenia Spazio (ALS) gained experience on the remote interaction techniques as a results of collaborations established both on European Communities (EC) initiatives, with Alenia Aeronautica (ALA) and Politecnico of Torino (POLITO). The H/W and S/W components performances increase and costs reduction due to the home computing massive utilization (especially demanded by the games business) together with the network technology possibility (offered by the web as well as the hi-speed links and the wireless communications) allow today to re-think the traditional AIT process activities in the light of the multimedia data exchange: graphical, voice video and by sure more in the future. Aerospace business confirm its innovation vocation which in the year '80 represents the cradle of the CAD systems and today is oriented to the 3D data visualization/ interaction technologies and remote visualisation/ interaction in collaborative way on a much more user friendly bases (i.e. not for specialists). Fig. 1 collects AIT extended scenario studied and adopted by ALS in these years. ALS experimented two possibilities of remote visualization/interaction: Portable [e.g. Fig.2 Personal Digital Assistant (PDA), Wearable] and walls (e.g.VR-Lab) screens as both 2D/3D visualisation and interaction devices which could support many types of traditional (mainly based on EGSE and PDM/CAD utilisation/reports) company internal AIT applications: 1. design review support 2. facility management 3. storage management 4. personnel training 5. integration sequences definition 6. assembly and test operations follow up 7. documentation review and external access to AIT activities for remote operations (e.g. tele-testing) EGSE Portable Clean room

  7. Avalanches in Wood Compression.

    PubMed

    Mäkinen, T; Miksic, A; Ovaska, M; Alava, Mikko J

    2015-07-31

    Wood is a multiscale material exhibiting a complex viscoplastic response. We study avalanches in small wood samples in compression. "Woodquakes" measured by acoustic emission are surprisingly similar to earthquakes and crackling noise in rocks and laboratory tests on brittle materials. Both the distributions of event energies and of waiting (silent) times follow power laws. The stress-strain response exhibits clear signatures of localization of deformation to "weak spots" or softwood layers, as identified using digital image correlation. Even though material structure-dependent localization takes place, the avalanche behavior remains scale-free. PMID:26274428

  8. Standards Development Activities at White Sands Test Facility

    NASA Technical Reports Server (NTRS)

    Baker, D. L.; Beeson, H. D.; Saulsberry, R. L.; Julien, H. L.; Woods, S. S.

    2003-01-01

    The development of standards and standard activities at the JSC White Sands Test Facility (WSTF) has been expanded to include the transfer of technology and standards to voluntary consensus organizations in five technical areas of importance to NASA. This effort is in direct response to the National Technology Transfer Act designed to accelerate transfer of technology to industry and promote government-industry partnerships. Technology transfer is especially important for WSTF, whose longterm mission has been to develop and provide vital propellant safety and hazards information to aerospace designers, operations personnel, and safety personnel. Meeting this mission is being accomplished through the preparation of consensus guidelines and standards, propellant hazards analysis protocols, and safety courses for the propellant use of hydrogen, oxygen, and hypergols, as well as the design and inspection of spacecraft pressure vessels and the use of pyrovalves in spacecraft propulsion systems. The overall WSTF technology transfer program is described and the current status of technology transfer activities are summarized.

  9. Testing Punctuated Equilibrium Theory Using Evolutionary Activity Statistics

    NASA Astrophysics Data System (ADS)

    Woodberry, O. G.; Korb, K. B.; Nicholson, A. E.

    The Punctuated Equilibrium hypothesis (Eldredge and Gould,1972) asserts that most evolutionary change occurs during geologically rapid speciation events, with species exhibiting stasis most of the time. Punctuated Equilibrium is a natural extension of Mayr's theories on peripatric speciation via the founder effect, (Mayr, 1963; Eldredge and Gould, 1972) which associates changes in diversity to a population bottleneck. That is, while the formation of a foundation bottleneck brings an initial loss of genetic variation, it may subsequently result in the emergence of a child species distinctly different from its parent species. In this paper we adapt Bedau's evolutionary activity statistics (Bedau and Packard, 1991) to test these effects in an ALife simulation of speciation. We find a relative increase in evolutionary activity during speciations events, indicating that punctuation is occurring.

  10. The behavior of compression and degradation for municipal solid waste and combined settlement calculation method.

    PubMed

    Shi, Jianyong; Qian, Xuede; Liu, Xiaodong; Sun, Long; Liao, Zhiqiang

    2016-09-01

    The total compression of municipal solid waste (MSW) consists of primary, secondary, and decomposition compressions. It is usually difficult to distinguish between the three parts of compressions. In this study, the odeometer test was used to distinguish between the primary and secondary compressions to determine the primary and secondary compression coefficient. In addition, the ending time of the primary compressions were proposed based on municipal solid waste compression tests in a degradation-inhibited condition by adding vinegar. The amount of the secondary compression occurring in the primary compression stage has a relatively high percentage to either the total compression or the total secondary compression. The relationship between the degradation ratio and time was obtained from the tests independently. Furthermore, a combined compression calculation method of municipal solid waste for all three parts of compressions including considering organics degradation is proposed based on a one-dimensional compression method. The relationship between the methane generation potential L0 of LandGEM model and degradation compression index was also discussed in the paper. A special column compression apparatus system, which can be used to simulate the whole compression process of municipal solid waste in China, was designed. According to the results obtained from 197-day column compression test, the new combined calculation method for municipal solid waste compression was analyzed. The degradation compression is the main part of the compression of MSW in the medium test period. PMID:26548978

  11. Prevention of deep vein thrombosis in potential neurosurgical patients. A randomized trial comparing graduated compression stockings alone or graduated compression stockings plus intermittent pneumatic compression with control

    SciTech Connect

    Turpie, A.G.; Hirsh, J.; Gent, M.; Julian, D.; Johnson, J.

    1989-03-01

    In a randomized trial of neurosurgical patients, groups wearing graduated compression stockings alone (group 1) or graduated compression stockings plus intermittent pneumatic compression (IPC) (group 2) were compared with an untreated control group in the prevention of deep vein thrombosis (DVT). In both active treatment groups, the graduated compression stockings were continued for 14 days or until hospital discharge, if earlier. In group 2, IPC was continued for seven days. All patients underwent DVT surveillance with iodine 125-labeled fibrinogen leg scanning and impedance plethysmography. Venography was carried out if either test became abnormal. Deep vein thrombosis occurred in seven (8.8%) of 80 patients in group 1, in seven (9.0%) of 78 patients in group 2, and in 16 (19.8%) of 81 patients in the control group. The observed differences among these rates are statistically significant. The results of this study indicate that graduated compression stockings alone or in combination with IPC are effective methods of preventing DVT in neurosurgical patients.

  12. Strain Gage Loads Calibration Testing of the Active Aeroelastic Wing F/A-18 Aircraft

    NASA Technical Reports Server (NTRS)

    Lokos, William A.; Olney, Candida D.; Chen, Tony; Crawford, Natalie D.; Stauf, Rick; Reichenbach, Eric Y.; Bessette, Denis (Technical Monitor)

    2002-01-01

    This report describes strain-gage calibration loading through the application of known loads of the Active Aeroelastic Wing F/A-18 airplane. The primary goal of this test is to produce a database suitable for deriving load equations for left and right wing root and fold shear; bending moment; torque; and all eight wing control-surface hinge moments. A secondary goal is to produce a database of wing deflections measured by string potentiometers and the onboard flight deflection measurement system. Another goal is to produce strain-gage data through both the laboratory data acquisition system and the onboard aircraft data system as a check of the aircraft system. Thirty-two hydraulic jacks have applied loads through whiffletrees to 104 tension-compression load pads bonded to the lower wing surfaces. The load pads covered approximately 60 percent of the lower wing surface. A series of 72 load cases has been performed, including single-point, double-point, and distributed load cases. Applied loads have reached 70 percent of the flight limit load. Maximum wingtip deflection has reached nearly 16 in.

  13. Design and test of three active flutter suppression controllers

    NASA Technical Reports Server (NTRS)

    Christhilf, David M.; Waszak, Martin R.; Adams, William M.; Srinathkumar, S.; Mukhopadhyay, Vivek

    1991-01-01

    Three flutter suppression control law design techniques are presented. Each uses multiple control surfaces and/or sensors. The first uses linear combinations of several accelerometer signals together with dynamic compensation to synthesize the modal rate of the critical mode for feedback to distributed control surfaces. The second uses traditional tools (pole/zero loci and Nyquist diagrams) to develop a good understanding of the flutter mechanism and produce a controller with minimal complexity and good robustness to plant uncertainty. The third starts with a minimum energy Linear Quadratic Gaussian controller, applies controller order reduction, and then modifies weight and noise covariance matrices to improve multi-variable robustness. The resulting designs were implemented digitally and tested subsonically on the Active Flexible Wing (AFW) wind tunnel model. Test results presented here include plant characteristics, maximum attained closed-loop dynamic pressure, and Root Mean Square control surface activity. A key result is that simultaneous symmetric and antisymmetric flutter suppression was achieved by the second control law, with a 24 percent increase in attainable dynamic pressure.

  14. Tc-99 Adsorption on Selected Activated Carbons - Batch Testing Results

    SciTech Connect

    Mattigod, Shas V.; Wellman, Dawn M.; Golovich, Elizabeth C.; Cordova, Elsa A.; Smith, Ronald M.

    2010-12-01

    CH2M HILL Plateau Remediation Company (CHPRC) is currently developing a 200-West Area groundwater pump-and-treat system as the remedial action selected under the Comprehensive Environmental Response, Compensation, and Liability Act Record of Decision for Operable Unit (OU) 200-ZP-1. This report documents the results of treatability tests Pacific Northwest National Laboratory researchers conducted to quantify the ability of selected activated carbon products (or carbons) to adsorb technetium-99 (Tc-99) from 200-West Area groundwater. The Tc-99 adsorption performance of seven activated carbons (J177601 Calgon Fitrasorb 400, J177606 Siemens AC1230AWC, J177609 Carbon Resources CR-1240-AW, J177611 General Carbon GC20X50, J177612 Norit GAC830, J177613 Norit GAC830, and J177617 Nucon LW1230) were evaluated using water from well 299-W19-36. Four of the best performing carbons (J177606 Siemens AC1230AWC, J177609 Carbon Resources CR-1240-AW, J177611 General Carbon GC20X50, and J177613 Norit GAC830) were selected for batch isotherm testing. The batch isotherm tests on four of the selected carbons indicated that under lower nitrate concentration conditions (382 mg/L), Kd values ranged from 6,000 to 20,000 mL/g. In comparison. Under higher nitrate (750 mg/L) conditions, there was a measureable decrease in Tc-99 adsorption with Kd values ranging from 3,000 to 7,000 mL/g. The adsorption data fit both the Langmuir and the Freundlich equations. Supplemental tests were conducted using the two carbons that demonstrated the highest adsorption capacity to resolve the issue of the best fit isotherm. These tests indicated that Langmuir isotherms provided the best fit for Tc-99 adsorption under low nitrate concentration conditions. At the design basis concentration of Tc 0.865 µg/L(14,700 pCi/L), the predicted Kd values from using Langmuir isotherm constants were 5,980 mL/g and 6,870 mL/g for for the two carbons. These Kd values did not meet the target Kd value of 9,000 mL/g. Tests

  15. German National Galileo Public Regulated Service (PRS) Testing Activities

    NASA Astrophysics Data System (ADS)

    Habrich, Heinz; Söhne, Wolfgang

    2013-04-01

    The European Global Navigation System (GNSS) Galileo is going to be established in the near future. Currently, four satellites are in place forming the In-Orbit-Testing (IOT) phase. Within the next years, the constellation will be filled. Full Operational Capability (FOC) will be reached 2019. Beside the Open Service (OS) which is comparable to other OS of existing GNSS, e.g., GPS C/A, there is a so-called Public Regulated Service (PRS) included in the IOT satellites already. The PRS will have improved robustness, i.e. robust signals which will be resistant against involuntary interferences, jamming and spoofing. The PRS signal is encrypted and there will be a restricted access to authorized users, e.g. safety and emergency services, authorities with security task, critical infrastructure organizations etc. The access to the PRS which will be controlled through a special key management will be managed and supervised within the European Union (EU) Member States (MS) by national authorities, the Competent PRS Authority (CPA). But a set of Common Minimum Standards (CMS) will define the minimum requirements applicable to each PRS participant. Nevertheless, each MS is responsible for its national key management. This presentation will inform about the testing activities for Galileo PRS in Germany. The coarse concept for the testing is explained, the schedule is outlined. Finally, the paper will formulate some expectations to the Galileo PRS, e.g. for international cooperation.

  16. Testing and evaluation for astronaut extravehicular activity (EVA) operability.

    PubMed

    Shields, N; King, L C

    1998-09-01

    Because it is the human component that defines space mission success, careful planning is required to ensure that hardware can be operated and maintained by crews on-orbit. Several methods exist to allow researchers and designers to better predict how hardware designs will behave under the harsh environment of low Earth orbit, and whether designs incorporate the necessary features for Extra Vehicular Activity (EVA) operability. Testing under conditions of simulated microgravity can occur during the design concept phase when verifying design operability, during mission training, or concurrently with on-orbit mission operations. The bulk of testing is focused on normal operations, but also includes evaluation of credible mission contingencies or "what would happen if" planning. The astronauts and cosmonauts who fly these space missions are well prepared and trained to survive and be productive in Earth's orbit. The engineers, designers, and training crews involved in space missions subject themselves to Earth based simulation techniques that also expose them to extreme environments. Aircraft falling ten thousand feet, alternating g-loads, underwater testing at 45 foot depth, enclosure in a vacuum chamber and subject to thermal extremes, each carries with it inherent risks to the humans preparing for space missions. PMID:12190075

  17. Investigation of Cyclic Deformation and Fatigue of Polycrystalline Cu under Pure Compression Cyclic Loading Conditions

    NASA Astrophysics Data System (ADS)

    Hsu, Tzu-Yin Jean

    It is commonly accepted that fatigue crack is initiated under tensile fatigue stresses. However, practical examples demonstrate that cracks may also initiate under pure compressive fluctuating loads such as the failures observed in aircraft landing gear frames. However, the mechanism of such failures is rarely investigated. Furthermore, knowledge on cyclic deformation response under pure compressive fatigue condition is also very limited or non-existent. Our recent work already verified that fatigue cracks may nucleate from stress concentration sites under pure compression fatigue, but whether or not a form of stress concentration is always needed to initiate a crack under pure compression fatigue remains uncertain. In this study, compression fatigue tests under different peak stresses were carried out on smooth bars of fully annealed OFHC Copper. The purpose of these tests is to investigate not only the cyclic deformation response but also the possibility of crack nucleation without the stress concentrator. Results showed that overall the cyclic stress-strain response and microstructural evolution of OFHC Copper under pure compression fatigue exhibits rather dissimilar behaviour compared to those under symmetrical fatigue. The specimens hardened rapidly within 10 cycles under pure compression fatigue unlike the gradual cyclic hardening behaviour in symmetrical fatigue with the same peak stress amplitude. Compressive cyclic creep behaviour was also observed under the same testing conditions. Moreover, unlike conventional tension-compression fatigue, only moderate slip activity was detectable on the surface instead of typical PSB features detected from TEM observations. The surface observations has revealed that surface slip bands did not increase in number nor did they become more pronounced in height with increasing number of cycles. In addition, surface roughening by grain boundary extrusion was detected to become more severe as the cycling progressed. Therefore

  18. Analysis of Heat and Compressibility Effects in Internal Flow Systems and High-Speed Tests of a Ram-Jet System

    NASA Technical Reports Server (NTRS)

    Becker, John V; Baals, Donald D

    1943-01-01

    An analysis has been made by the NACA of the effects of heat and compressibility in the flow through the internal systems of aircraft. Equations and charts are developed whereby the flow characteristics at key stations in a typical internal system may be readily obtained.

  19. Effects of the Simultaneous Application of Nonlinear Frequency Compression and Dichotic Hearing on the Speech Recognition of Severely Hearing-Impaired Subjects: Simulation Test

    PubMed Central

    Hwang, Jong Ho; Nam, Kyoung Won; Yoon, Sung Hoon; Kim, Jinryoul; Yook, Sunhyun; Hong, Sung Hwa; Jang, Dong Pyo

    2015-01-01

    Objectives The clinical effects of the simultaneous application of nonlinear frequency compression and dichotic hearing on people with hearing impairments have not been evaluated previously. In this study, the clinical effects of the simultaneous application of these two techniques on the recognition of consonant-vowel-consonant (CVC) words with fricatives were evaluated using normal-hearing subjects and a hearing loss simulator operated in the severe hearing loss setting. Methods A total of 21 normal-hearing volunteers whose native language was English were recruited for this study, and two different hearing loss simulators, which were configured for severe hearing loss in the high-frequency range, were utilized. The subjects heard 82 English CVC words, and the word recognition score and response time were measured. Results The experimental results demonstrated that the simultaneous application of these two techniques showed almost even performance compared to the sole application of nonlinear frequency compression in a severe hearing loss setting. Conclusion Though it is generally accepted that dichotic hearing can decrease the spectral masking thresholds of an hearing-impaired person, simultaneous application of the nonlinear frequency compression and dichotic hearing techniques did not significantly improve the recognition of words with fricatives compared to the sole application of nonlinear frequency compression in a severe hearing loss setting. PMID:26045907

  20. Ceftaroline activity tested against viridans group streptococci from US hospitals.

    PubMed

    Sader, Helio S; Rhomberg, Paul R; Castanheira, Mariana; Farrell, David J; Flamm, Robert K; Mendes, Rodrigo E; Jones, Ronald N

    2016-03-01

    A total of 840 clinically relevant viridans group streptococci (VGS) isolates (1/patient episode) were collected from 71 US medical centers in 2013-2014. These organisms were tested for susceptibility by reference broth microdilution methods against ceftaroline and selected comparator agents. All isolates were speciated by matrix-assisted laser desorption ionization-time-of-flight (MALDI-TOF) mass spectrometry and were primarily from skin/soft tissue (32.6%) and bloodstream (32.3%) infections. Ceftaroline was highly active against all VGS species/groups with MIC50 and MIC90 values ranging from ≤0.015 to 0.03μg/mL and ≤0.015 to 0.06μg/mL, respectively. The highest ceftaroline MIC value was only 0.5μg/mL (0.5% of strains) and ceftaroline (MIC50/90, 0.03/0.06μg/mL) was 8-fold more active than ceftriaxone (MIC50/90, 0.25/0.5μg/mL). The VGS groups most susceptible to ceftaroline were Streptococcus mutans and Streptococcus bovis (MIC90, ≤0.015μg/mL), whereas the highest ceftaroline MIC values were observed among Streptococcus mitis and Streptococcus sanguinis groups. In summary, ceftaroline exhibited potent in vitro activity against VGS, including many uncommonly isolated species/groups for which very limited susceptibility information is currently available to guide therapy. PMID:26658313

  1. Haloxon: critical tests of antiparasitic activity in equids.

    PubMed

    Lyons, E T; Drudge, J H; Tolliver, S C

    1981-06-01

    Critical tests were conducted in 14 naturally infected equids (13 horses and 1 pony) to evaluate the antiparasitic activity of haloxon. Single doses were administered by stomach tube to 3 horses and 1 pony (60 mg/kg of body weight), by addition to the feed of 3 horses (60 mg/kg), and intraorally by powder gun to 7 horses (65 mg/kg). Haloxon was efficacious (99% to 100%) against infections of Parascaris equorum, Oxyuris equi (mature and immature), and Strongylus vulgaris at both dosage levels. Probstmayria vivipara parasites were removed in 1 horse treated at 60 mg/kg by stomach tube and S equinus was removed (1 specimen) in 1 horse treated at 65 mg/kg with the powder gun. Removal activity against small strongyles varied from 67% to 92%, and averaged 88% in ther aggregate. Removal of S edentatus fluctuated from 2% to 100%, and was 49% in the aggregate. Haloxon was generally ineffective against Gasterophilus intestinalis and G nasalis, except that it seemed active against 2nd instar G intestinalis when administered at the 60 mg/kg dosage rate in feed and at the 65 mg/kg dosage rate by powder gun. The compound was inactive against Trichostrongylus axei, Habronema muscae, Draschia megastoma, Anoplocephala perfoliata, and A magna. Clinical signs of toxicosis were not observed after treatment. Problems were not encountered in administration of haloxon directly into the back of the mouth with the powder gun. PMID:7283234

  2. Basophil activation test: food challenge in a test tube or specialist research tool?

    PubMed

    Santos, Alexandra F; Lack, Gideon

    2016-01-01

    Oral food challenge (OFC) is the gold-standard to diagnose food allergy; however, it is a labour and resource-intensive procedure with the risk of causing an acute allergic reaction, which is potentially severe. Therefore, OFC are reserved for cases where the clinical history and the results of skin prick test and/or specific IgE do not confirm or exclude the diagnosis of food allergy. This is a significant proportion of patients seen in Allergy clinics and results in a high demand for OFC. The basophil activation test (BAT) has emerged as a new diagnostic test for food allergy. With high diagnostic accuracy, it can be particularly helpful in the cases where skin prick test and specific IgE are equivocal and may allow reducing the need for OFC. BAT has high specificity, which confers a high degree of certainty in confirming the diagnosis of food allergy and allows deferring the performance of OFC in patients with a positive BAT. The diagnostic utility of BAT is allergen-specific and needs to be validated for different allergens and in specific patient populations. Standardisation of the laboratory methodology and of the data analyses would help to enable a wider clinical application of BAT. PMID:26981234

  3. [Activity of ISO/TC212, clinical laboratory testing and in vitro diagnostic test systems].

    PubMed

    Kawai, T

    1998-10-01

    ISO is the International Organization for Standardization, which is a worldwide federation of national standards bodies from 130 countries, one from each country. ISO is a non-governmental organization established in 1947. ISO/TC212, Clinical laboratory testing and in vitro diagnostic test systems was newly established in 1995, consisting of 86 P-members and 12 O-members. ISO/TC212 secretariat is the American National Standards Institute, and NCCLS carries out its secretarial activity. On behalf of the Japanese Industrial Standards Committee (JISC), the Japanese Committee for Clinical Laboratory Standards (JCCLS) serves as the secretariat for the ISO/TC212 National Technical Advisory Group. Three working groups are in the process of preparing the Draft International Standards (DIS) among 9 work items. The next plenary session of ISO/TC212 will be held on May 19-21, 1999 in Tokyo, Japan. PMID:9816905

  4. Development of a preprototype vapor compression distillation water recovery subsystem

    NASA Technical Reports Server (NTRS)

    Johnson, K. L.

    1978-01-01

    The activities involved in the design, development, and test of a preprototype vapor compression distillation water recovery subsystem are described. This subsystem, part of a larger regenerative life support evaluation system, is designed to recover usable water from urine, urinal rinse water, and concentrated shower and laundry brine collected from three space vehicle crewmen for a period of 180 days without resupply. Details of preliminary design and testing as well as component developments are included. Trade studies, considerations leading to concept selections, problems encountered, and test data are also presented. The rework of existing hardware, subsystem development including computer programs, assembly verification, and comprehensive baseline test results are discussed.

  5. Learning in compressed space.

    PubMed

    Fabisch, Alexander; Kassahun, Yohannes; Wöhrle, Hendrik; Kirchner, Frank

    2013-06-01

    We examine two methods which are used to deal with complex machine learning problems: compressed sensing and model compression. We discuss both methods in the context of feed-forward artificial neural networks and develop the backpropagation method in compressed parameter space. We further show that compressing the weights of a layer of a multilayer perceptron is equivalent to compressing the input of the layer. Based on this theoretical framework, we will use orthogonal functions and especially random projections for compression and perform experiments in supervised and reinforcement learning to demonstrate that the presented methods reduce training time significantly. PMID:23501172

  6. Neutron activation analysis; A sensitive test for trace elements

    SciTech Connect

    Hossain, T.Z. . Ward Lab.)

    1992-01-01

    This paper discusses neutron activation analysis (NAA), an extremely sensitive technique for determining the elemental constituents of an unknown specimen. Currently, there are some twenty-five moderate-power TRIGA reactors scattered across the United States (fourteen of them at universities), and one of their principal uses is for NAA. NAA is procedurally simple. A small amount of the material to be tested (typically between one and one hundred milligrams) is irradiated for a period that varies from a few minutes to several hours in a neutron flux of around 10{sup 12} neutrons per square centimeter per second. A tiny fraction of the nuclei present (about 10{sup {minus}8}) is transmuted by nuclear reactions into radioactive forms. Subsequently, the nuclei decay, and the energy and intensity of the gamma rays that they emit can be measured in a gamma-ray spectrometer.

  7. Mycobactericidal activity of selected disinfectants using a quantitative suspension test.

    PubMed

    Griffiths, P A; Babb, J R; Fraise, A P

    1999-02-01

    In this study, a quantitative suspension test carried out under both clean and dirty conditions was used to assess the activity of various instrument and environmental disinfectants against the type strain NCTC 946 and an endoscope washer disinfector isolate of Mycobacterium chelonae, Mycobacterium fortuitum NCTC 10,394, Mycobacterium tuberculosis H37 Rv NCTC 7416 and a clinical isolate of Mycobacterium avium-intracellulare (MAI). The disinfectants tested were; a chlorine releasing agent, sodium dichloroisocyanurate (NaDCC) at 1000 ppm and 10,000 ppm av Cl; chlorine dioxide at 1100 ppm av ClO2 (Tristel, MediChem International Limited); 70% industrial methylated spirits (IMS); 2% alkaline glutaraldehyde (Asep, Galan); 10% succinedialdehyde and formaldehyde mixture (Gigasept, Schulke & Mayr); 0.35% peracetic acid (NuCidex, Johnson & Johnson); and a peroxygen compound at 1% and 3% (Virkon, Antec International). Results showed that the clinical isolate of MAI was much more resistant than M. tuberculosis to all the disinfectants, while the type strains of M. chelonae and M. fortuitum were far more sensitive. The washer disinfector isolate of M. chelonae was extremely resistant to 2% alkaline activated glutaraldehyde and appeared to be slightly more resistant than the type strain to Nu-Cidex, Gigasept, Virkon and the lower concentration of NaDCC. This study has shown peracetic acid (Nu-Cidex), chlorine dioxide (Tristel), alcohol (IMS) and high concentrations of a chlorine releasing agent (NaDCC) are rapidly mycobactericidal. Glutaraldehyde, although effective, is a slow mycobactericide. Gigasept and Virkon are poor mycobactericidal agents and are not therefore recommended for instruments or spillage if mycobacteria are likely to be present. PMID:10063473

  8. Design, test, and evaluation of three active flutter suppression controllers

    NASA Technical Reports Server (NTRS)

    Adams, William M., Jr.; Christhilf, David M.; Waszak, Martin R.; Mukhopadhyay, Vivek; Srinathkumar, S.

    1992-01-01

    Three control law design techniques for flutter suppression are presented. Each technique uses multiple control surfaces and/or sensors. The first method uses traditional tools (such as pole/zero loci and Nyquist diagrams) for producing a controller that has minimal complexity and which is sufficiently robust to handle plant uncertainty. The second procedure uses linear combinations of several accelerometer signals and dynamic compensation to synthesize the model rate of the critical mode for feedback to the distributed control surfaces. The third technique starts with a minimum-energy linear quadratic Gaussian controller, iteratively modifies intensity matrices corresponding to input and output noise, and applies controller order reduction to achieve a low-order, robust controller. The resulting designs were implemented digitally and tested subsonically on the active flexible wing wind-tunnel model in the Langley Transonic Dynamics Tunnel. Only the traditional pole/zero loci design was sufficiently robust to errors in the nominal plant to successfully suppress flutter during the test. The traditional pole/zero loci design provided simultaneous suppression of symmetric and antisymmetric flutter with a 24-percent increase in attainable dynamic pressure. Posttest analyses are shown which illustrate the problems encountered with the other laws.

  9. Basophil Activation Test with Food Additives in Chronic Urticaria Patients

    PubMed Central

    Kang, Min-Gyu; Song, Woo-Jung; Park, Han-Ki; Lim, Kyung-Hwan; Kim, Su-Jung; Lee, Suh-Young; Kim, Sae-Hoon; Cho, Sang-Heon; Min, Kyung-Up

    2014-01-01

    The role of food additives in chronic urticaria (CU) is still under investigation. In this study, we aimed to explore the association between food additives and CU by using the basophil activation test (BAT). The BAT using 15 common food additives was performed for 15 patients with CU who had a history of recurrent urticarial aggravation following intake of various foods without a definite food-specific IgE. Of the 15 patients studied, two (13.3%) showed positive BAT results for one of the tested food additives. One patient responded to monosodium glutamate, showing 18.7% of CD203c-positive basophils. Another patient showed a positive BAT result to sodium benzoate. Both patients had clinical correlations with the agents, which were partly determined by elimination diets. The present study suggested that at least a small proportion of patients with CU had symptoms associated with food additives. The results may suggest the potential utility of the BAT to identity the role of food additives in CU. PMID:24527415

  10. U.S. Department of Energy FreedomCAR & Vehicle Technologies Program Advanced Vehicle Testing Activity, Hydrogen/CNG Blended Fuels Performance Testing in a Ford F-150

    SciTech Connect

    James E. Francfort

    2003-11-01

    Federal regulation requires energy companies and government entities to utilize alternative fuels in their vehicle fleets. To meet this need, several automobile manufacturers are producing compressed natural gas (CNG)-fueled vehicles. In addition, several converters are modifying gasoline-fueled vehicles to operate on both gasoline and CNG (Bifuel). Because of the availability of CNG vehicles, many energy company and government fleets have adopted CNG as their principle alternative fuel for transportation. Meanwhile, recent research has shown that blending hydrogen with CNG (HCNG) can reduce emissions from CNG vehicles. However, blending hydrogen with CNG (and performing no other vehicle modifications) reduces engine power output, due to the lower volumetric energy density of hydrogen in relation to CNG. Arizona Public Service (APS) and the U.S. Department of Energy’s Advanced Vehicle Testing Activity (DOE AVTA) identified the need to determine the magnitude of these effects and their impact on the viability of using HCNG in existing CNG vehicles. To quantify the effects of using various blended fuels, a work plan was designed to test the acceleration, range, and exhaust emissions of a Ford F-150 pickup truck operating on 100% CNG and blends of 15 and 30% HCNG. This report presents the results of this testing conducted during May and June 2003 by Electric Transportation Applications (Task 4.10, DOE AVTA Cooperative Agreement DEFC36- 00ID-13859).

  11. Ultrasound strain mapping of Achilles tendon compressive strain patterns during dorsiflexion.

    PubMed

    Chimenti, Ruth L; Flemister, A Samuel; Ketz, John; Bucklin, Mary; Buckley, Mark R; Richards, Michael S

    2016-01-01

    Heel lifts are commonly prescribed to patients with Achilles tendinopathy, yet little is known about the effect on tendon compressive strain. The purposes of the current study were to (1) develop a valid and reliable ultrasound elastography technique and algorithm to measure compressive strain of human Achilles tendon in vivo, (2) examine the effects of ankle dorsiflexion (lowering via controlled removal of a heel lift and partial squat) on compressive strain of the Achilles tendon insertion and (3) examine the relative compressive strain between the deep and superficial regions of the Achilles tendon insertion. All tasks started in a position equivalent to standing with a 30mm heel lift. An ultrasound transducer positioned over the Achilles tendon insertion was used to capture radiofrequency images. A non-rigid image registration-based algorithm was used to estimate compressive strain of the tendon, which was divided into 2 regions (superficial, deep). The bland-Altman test and intraclass correlation coefficient were used to test validity and reliability. One-way repeated measures ANOVA was used to compare compressive strain between regions and across tasks. Compressive strain was accurately and reliably (ICC>0.75) quantified. There was greater compressive strain during the combined task of lowering and partial squat compared to the lowering (P=.001) and partial squat (P<.001) tasks separately. There was greater compressive strain in the deep region of the tendon compared to the superficial for all tasks (P=.001). While these findings need to be examined in a pathological population, heel lifts may reduce tendon compressive strain during daily activities. PMID:26655590

  12. Spectral image compression for data communications

    NASA Astrophysics Data System (ADS)

    Hauta-Kasari, Markku; Lehtonen, Juha; Parkkinen, Jussi P. S.; Jaeaeskelaeinen, Timo

    2000-12-01

    We report a technique for spectral image compression to be used in the field of data communications. The spectral domain of the images is represented by a low-dimensional component image set, which is used to obtain an efficient compression of the high-dimensional spectral data. The component images are compressed using a similar technique as the JPEG- and MPEG-type compressions use to subsample the chrominance channels. The spectral compression is based on Principal Component Analysis (PCA) combined with color image transmission coding technique of 'chromatic channel subsampling' of the component images. The component images are subsampled using 4:2:2, 4:2:0, and 4:1:1-based compressions. In addition, we extended the test for larger block sizes and larger number of component images than in the original JPEG- and MPEG-standards. Totally 50 natural spectral images were used as test material in our experiments. Several error measures of the compression are reported. The same compressions are done using Independent Component Analysis and the results are compared with PCA. These methods give a good compression ratio while keeping visual quality of color still good. Quantitative comparisons between the original and reconstructed spectral images are presented.

  13. Prechamber Compression-Ignition Engine Performance

    NASA Technical Reports Server (NTRS)

    Moore, Charles S; Collins, John H , Jr

    1938-01-01

    Single-cylinder compression-ignition engine tests were made to investigate the performance characteristics of prechamber type of cylinder head. Certain fundamental variables influencing engine performance -- clearance distribution, size, shape, and direction of the passage connecting the cylinder and prechamber, shape of prechamber, cylinder clearance, compression ratio, and boosting -- were independently tested. Results of motoring and of power tests, including several typical indicator cards, are presented.

  14. Syringe test (modified larval immersion test): a new bioassay for testing acaricidal activity of plant extracts against Rhipicephalus microplus.

    PubMed

    Sindhu, Zia-ud-Din; Jonsson, Nicholas N; Iqbal, Zafar

    2012-09-10

    We report a new bioassay "syringe test" (modified larval immersion test) for in vitro evaluation of acaricidal activity of crude plant extracts. Prepared syringes, containing eggs of tick, were incubated until 14 d after hatching of eggs, when the bioassay was performed on the larvae. Lethal concentrations for 50% of larvae (LC(50)), LC(90) and LC(99) values were calculated for each tested product. 95% confidence intervals for LC(50) were very narrow, indicating a high degree of repeatability for the new bioassay on larvae of R. microplus. Bioassays were applied to six crude aqueous-methanol extracts from five plants (Acacia nilotica, Buxus papillosa, Fumaria parviflora, Juniperus excelsa, and Operculina turpethum), of which three showed discernible effects. Twenty-four hours post exposure, LC(99) values were 11.9% (w/v) for F. parviflora, 20.8% (w/v) and 29.2% (w/v) for B. papillosa and A. nilotica, respectively. After six days of exposure these values were; 9.1% (w/v), 9.2% (w/v) and 15.5 (w/v) for F. parviflora, A. nilotica and B. papillosa, respectively. PMID:22516644

  15. Microbunching and RF Compression

    SciTech Connect

    Venturini, M.; Migliorati, M.; Ronsivalle, C.; Ferrario, M.; Vaccarezza, C.

    2010-05-23

    Velocity bunching (or RF compression) represents a promising technique complementary to magnetic compression to achieve the high peak current required in the linac drivers for FELs. Here we report on recent progress aimed at characterizing the RF compression from the point of view of the microbunching instability. We emphasize the development of a linear theory for the gain function of the instability and its validation against macroparticle simulations that represents a useful tool in the evaluation of the compression schemes for FEL sources.

  16. HAL/S-360 compiler test activity report

    NASA Technical Reports Server (NTRS)

    Helmers, C. T.

    1974-01-01

    The levels of testing employed in verifying the HAL/S-360 compiler were as follows: (1) typical applications program case testing; (2) functional testing of the compiler system and its generated code; and (3) machine oriented testing of compiler implementation on operational computers. Details of the initial test plan and subsequent adaptation are reported, along with complete test results for each phase which examined the production of object codes for every possible source statement.

  17. Recoil Experiments Using a Compressed Air Cannon

    ERIC Educational Resources Information Center

    Taylor, Brett

    2006-01-01

    Ping-Pong vacuum cannons, potato guns, and compressed air cannons are popular and dramatic demonstrations for lecture and lab. Students enjoy them for the spectacle, but they can also be used effectively to teach physics. Recently we have used a student-built compressed air cannon as a laboratory activity to investigate impulse, conservation of…

  18. Compressive Sensing DNA Microarrays

    PubMed Central

    2009-01-01

    Compressive sensing microarrays (CSMs) are DNA-based sensors that operate using group testing and compressive sensing (CS) principles. In contrast to conventional DNA microarrays, in which each genetic sensor is designed to respond to a single target, in a CSM, each sensor responds to a set of targets. We study the problem of designing CSMs that simultaneously account for both the constraints from CS theory and the biochemistry of probe-target DNA hybridization. An appropriate cross-hybridization model is proposed for CSMs, and several methods are developed for probe design and CS signal recovery based on the new model. Lab experiments suggest that in order to achieve accurate hybridization profiling, consensus probe sequences are required to have sequence homology of at least 80% with all targets to be detected. Furthermore, out-of-equilibrium datasets are usually as accurate as those obtained from equilibrium conditions. Consequently, one can use CSMs in applications in which only short hybridization times are allowed. PMID:19158952

  19. Compressible turbulent mixing: Effects of compressibility

    NASA Astrophysics Data System (ADS)

    Ni, Qionglin

    2016-04-01

    We studied by numerical simulations the effects of compressibility on passive scalar transport in stationary compressible turbulence. The turbulent Mach number varied from zero to unity. The difference in driven forcing was the magnitude ratio of compressive to solenoidal modes. In the inertial range, the scalar spectrum followed the k-5 /3 scaling and suffered negligible influence from the compressibility. The growth of the Mach number showed (1) a first reduction and second enhancement in the transfer of scalar flux; (2) an increase in the skewness and flatness of the scalar derivative and a decrease in the mixed skewness and flatness of the velocity-scalar derivatives; (3) a first stronger and second weaker intermittency of scalar relative to that of velocity; and (4) an increase in the intermittency parameter which measures the intermittency of scalar in the dissipative range. Furthermore, the growth of the compressive mode of forcing indicated (1) a decrease in the intermittency parameter and (2) less efficiency in enhancing scalar mixing. The visualization of scalar dissipation showed that, in the solenoidal-forced flow, the field was filled with the small-scale, highly convoluted structures, while in the compressive-forced flow, the field was exhibited as the regions dominated by the large-scale motions of rarefaction and compression.

  20. The role of molecular motors in the mechanics of active gels and the effects of inertia, hydrodynamic interaction and compressibility in passive microrheology

    NASA Astrophysics Data System (ADS)

    Uribe, Andres Cordoba

    The mechanical properties of soft biological materials are essential to their physiological function and cannot easily be duplicated by synthetic materials. The study of the mechanical properties of biological materials has lead to the development of new rheological characterization techniques. In the technique called passive microbead rheology, the positional autocorrelation function of a micron-sized bead embedded in a viscoelastic fluid is used to infer the dynamic modulus of the fluid. Single particle microrheology is limited to fluids were the microstructure is much smaller than the size of the probe bead. To overcome this limitation in two-bead microrheology the cross-correlated thermal motion of pairs of tracer particles is used to determine the dynamic modulus. Here we present a time-domain data analysis methodology and generalized Brownian dynamics simulations to examine the effects of inertia, hydrodynamic interaction, compressibility and non-conservative forces in passive microrheology. A type of biological material that has proven specially challenging to characterize are active gels. They are formed by semiflexible polymer filaments driven by motor proteins that convert chemical energy from the hydrolysis of adenosine triphosphate (ATP) to mechanical work and motion. Active gels perform essential functions in living tissue. Here we introduce a single-chain mean-field model to describe the mechanical properties of active gels. We model the semiflexible filaments as bead-spring chains and the molecular motors are accounted for by using a mean-field approach. The level of description of the model includes the end-to-end length and attachment state of the filaments, and the motor-generated forces, as stochastic state variables which evolve according to a proposed differential Chapman-Kolmogorov equation. The model allows accounting for physics that are not available in models that have been postulated on coarser levels of description. Moreover it allows

  1. 26 CFR 1.141-2 - Private activity bond tests.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... and 1.141-4. The private loan financing test is described in § 1.141-5. (d) Reasonable expectations... tests or the private loan financing test to be met. (2) Reasonable expectations test—(i) In general. In general, the reasonable expectations test must take into account reasonable expectations about events...

  2. Parametric and working fluid analysis of a combined organic Rankine-vapor compression refrigeration system activated by low-grade thermal energy.

    PubMed

    Saleh, B

    2016-09-01

    The potential use of many common hydrofluorocarbons and hydrocarbons as well as new hydrofluoroolefins, i.e. R1234yf and R1234ze(E) working fluids for a combined organic Rankine cycle and vapor compression refrigeration (ORC-VCR) system activated by low-grade thermal energy is evaluated. The basic ORC operates between 80 and 40 °C typical for low-grade thermal energy power plants while the basic VCR cycle operates between 5 and 40 °C. The system performance is characterized by the overall system coefficient of performance (COPS) and the total mass flow rate of the working fluid for each kW cooling capacity ([Formula: see text]). The effects of different working parameters such as the evaporator, condenser, and boiler temperatures on the system performance are examined. The results illustrate that the maximum COPS values are attained using the highest boiling candidates with overhanging T-s diagram, i.e. R245fa and R600, while R600 has the lowest [Formula: see text] under the considered operating conditions. Among the proposed candidates, R600 is the best candidate for the ORC-VCR system from the perspectives of environmental issues and system performance. Nevertheless, its flammability should attract enough attention. The maximum COPS using R600 is found to reach up to 0.718 at a condenser temperature of 30 °C and the basic values for the remaining parameters. PMID:27489732

  3. Compressed bitmap indices for efficient query processing

    SciTech Connect

    Wu, Kesheng; Otoo, Ekow; Shoshani, Arie

    2001-09-30

    Many database applications make extensive use of bitmap indexing schemes. In this paper, we study how to improve the efficiencies of these indexing schemes by proposing new compression schemes for the bitmaps. Most compression schemes are designed primarily to achieve good compression. During query processing they can be orders of magnitude slower than their uncompressed counterparts. The new schemes are designed to bridge this performance gap by reducing compression effectiveness and improving operation speed. In a number of tests on both synthetic data and real application data, we found that the new schemes significantly outperform the well-known compression schemes while using only modestly more space. For example, compared to the Byte-aligned Bitmap Code, the new schemes are 12 times faster and it uses only 50 percent more space. The new schemes use much less space(<30 percent) than the uncompressed scheme and are faster in a majority of the test cases.

  4. Testing Damage Scenarios. From Historical Earthquakes To Silent Active Faults

    NASA Astrophysics Data System (ADS)

    Galli, P.; Orsini, G.; Bosi, V.; di Pasquale, G.; Galadini, F.

    Italy is rich with historical scenarios of disruption and death that arrived up to us through the insight descriptions of hundreds of manuscripts, reports, treatises, letters and epigraphs. All these historical data constitute today one of the most powerful data-base of earthquake-induced effects. Moreover, it is now possible to relate many of these earthquakes to geological structures, the seismogenetic behavior of which has been investigated by means of paleoseismological studies. On the basis of these information and of those gathered through the national census (performed on popu- lation and dwellings by ISTAT, Italian Institute of Statistics in 1991) we developed a methodology (FaCES, Fault-Controlled Earthquake Scenario) which reproduce the damage scenario caused by the rupture of a defined fault, providing an estimate of the losses in terms of damages to building and consequences to population. The reliabil- ity of scenarios has been tested by comparing the historical damage distribution of an earthquake with that obtained applying FaCES to the responsible fault. Finally, we hypothesize the scenario related to three historically-silent faults of central Apennines (Mt. Vettore, Mt. Gorzano and Gran Sasso faults), the Holocene activity of which has been recently ascertained though paleoseimological analyses.

  5. Rapid toxicity testing based on mitochondrial respiratory activity

    SciTech Connect

    Haubenstricker, M.E. ); Holodnick, S.E.; Mancy, K.H. ); Brabec, M.J. )

    1990-05-01

    The need exists for rapid and inexpensive methods to determine the health effects of environmental contaminants on biological systems. One of the current research approaches for assessing cytotoxicity is to monitor the respiratory activity of the mitochondrion, a sensitive, nonspecific subcellular target site. Detected changes in mitochondrial function after the addition of a test chemical could be correlated to toxic effects. Mitochondrial respiration can be characterized by three indices: state 3 and state 4 respiratory rates, and the respiratory control ratio (RCR). State 4, the idle or resting state, results when coupled mitochondrial respire in a medium containing inorganic phosphate and a Kreb's cycle substrate in the absence of a phosphate acceptor such as adenosine diphosphate (ADP). In the presence of ADP the respiration rate increases to a maximum (state 3), accompanied by phosphorylation of ADP to adenosine triphosphate (ATP). The ratio of state 3 to state 4, or RCR, indicates how tightly the oxidative phosphorylation process is coupled. The synthesis of ATP by mitochondria is influenced by a number of compounds, most of which are either uncouplers or inhibitors.

  6. Vapor compression distillation module

    NASA Technical Reports Server (NTRS)

    Nuccio, P. P.

    1975-01-01

    A Vapor Compression Distillation (VCD) module was developed and evaluated as part of a Space Station Prototype (SSP) environmental control and life support system. The VCD module includes the waste tankage, pumps, post-treatment cells, automatic controls and fault detection instrumentation. Development problems were encountered with two components: the liquid pumps, and the waste tank and quantity gauge. Peristaltic pumps were selected instead of gear pumps, and a sub-program of materials and design optimization was undertaken leading to a projected life greater than 10,000 hours of continuous operation. A bladder tank was designed and built to contain the waste liquids and deliver it to the processor. A detrimental pressure pattern imposed upon the bladder by a force-operated quantity gauge was corrected by rearranging the force application, and design goals were achieved. System testing has demonstrated that all performance goals have been fulfilled.

  7. Lossy Text Compression Techniques

    NASA Astrophysics Data System (ADS)

    Palaniappan, Venka; Latifi, Shahram

    Most text documents contain a large amount of redundancy. Data compression can be used to minimize this redundancy and increase transmission efficiency or save storage space. Several text compression algorithms have been introduced for lossless text compression used in critical application areas. For non-critical applications, we could use lossy text compression to improve compression efficiency. In this paper, we propose three different source models for character-based lossy text compression: Dropped Vowels (DOV), Letter Mapping (LMP), and Replacement of Characters (ROC). The working principles and transformation methods associated with these methods are presented. Compression ratios obtained are included and compared. Comparisons of performance with those of the Huffman Coding and Arithmetic Coding algorithm are also made. Finally, some ideas for further improving the performance already obtained are proposed.

  8. Formulation study of directly compressible chewable polymers containing ascorbic acid.

    PubMed

    Kása, P; Jójárt, I; Kelemen, A; Pintye-Hódi, K

    2013-01-01

    The topic of this article is the compression physics of different gum bases which can be used to prepare chewing gum tablets by direct compression. Three different gum bases, Pharmagum(®) C, M and S, were tested alone and in different combinations. The preparations were compressed with a Korsch EK0 eccentric tableting machine at compression forces of 5, 7.5, 10, 12.5 and 15 kN. The compression and breaking processes and the physical parameters of the tablets were investigated. The results revealed that increase of the compression force did not significantly change the studied parameters of the tablets. PMID:22229257

  9. LOW ACTIVITY WASTE FEED SOLIDS CARACTERIZATION AND FILTERABILITY TESTS

    SciTech Connect

    McCabe, D.; Crawford, C.; Duignan, M.; Williams, M.; Burket, P.

    2014-04-03

    The primary treatment of the tank waste at the DOE Hanford site will be done in the Waste Treatment and Immobilization Plant (WTP) that is currently under construction. The baseline plan for the WTP Pretreatment facility is to treat the waste, splitting it into High Level Waste (HLW) feed and Low Activity Waste (LAW) feed. Both waste streams are then separately vitrified as glass and sealed in canisters. The LAW glass will be disposed onsite in the Integrated Disposal Facility (IDF). There are currently no plans to treat the waste to remove technetium in the WTP Pretreatment facility, so its disposition path is the LAW glass. Options are being explored to immobilize the LAW portion of the tank waste, i.e., the LAW feed from the WTP Pretreatment facility. Removal of {sup 99}Tc from the LAW Feed, followed by off-site disposal of the {sup 99}Tc, would eliminate a key risk contributor for the IDF Performance Assessment (PA) for supplemental waste forms, and has potential to reduce treatment and disposal costs. Washington River Protection Solutions (WRPS) is developing some conceptual flow sheets for LAW treatment and disposal that could benefit from technetium removal. One of these flowsheets will specifically examine removing {sup 99}Tc from the LAW feed stream to supplemental immobilization. The conceptual flow sheet of the {sup 99}Tc removal process includes a filter to remove insoluble solids prior to processing the stream in an ion exchange column, but the characteristics and behavior of the liquid and solid phases has not previously been investigated. This report contains results of testing of a simulant that represents the projected composition of the feed to the Supplemental LAW process. This feed composition is not identical to the aqueous tank waste fed to the Waste Treatment Plant because it has been processed through WTP Pretreatment facility and therefore contains internal changes and recycle streams that will be generated within the WTP process. Although

  10. Gas compression apparatus

    NASA Technical Reports Server (NTRS)

    Terp, L. S. (Inventor)

    1977-01-01

    Apparatus for transferring gas from a first container to a second container of higher pressure was devised. A free-piston compressor having a driving piston and cylinder, and a smaller diameter driven piston and cylinder, comprise the apparatus. A rod member connecting the driving and driven pistons functions for mutual reciprocation in the respective cylinders. A conduit may be provided for supplying gas to the driven cylinder from the first container. Also provided is apparatus for introducing gas to the driving piston, to compress gas by the driven piston for transfer to the second higher pressure container. The system is useful in transferring spacecraft cabin oxygen into higher pressure containers for use in extravehicular activities.

  11. Lossless compression of stromatolite images: a biogenicity index?

    PubMed

    Corsetti, Frank A; Storrie-Lombardi, Michael C

    2003-01-01

    It has been underappreciated that inorganic processes can produce stromatolites (laminated macroscopic constructions commonly attreibuted to microbiological activity), thus calling into question the long-standing use of stromatolites as de facto evidence for ancient life. Using lossless compression on unmagnified reflectance red-green-blue (RGB) images of matched stromatolite-sediment matrix pairs as a complexity metric, the compressibility index (delta(c), the log ratio of the ratio of the compressibility of the matrix versus the target) of a putative abiotic test stromatolite is significantly less than the delta(c) of a putative biotic test stromatolite. There is a clear separation in delta(c) between the different stromatolites discernible at the outcrop scale. In terms of absolute compressibility, the sediment matrix between the stromatolite columns was low in both cases, the putative abiotic stromatolite was similar to the intracolumnar sediment, and the putative biotic stromatolite was much greater (again discernible at the outcrop scale). We propose tht this metric would be useful for evaluating the biogenicity of images obtained by the camera systems available on every Mars surface probe launched to date including Viking, Pathfinder, Beagle, and the two Mars Exploration Rovers. PMID:14994715

  12. Technique for chest compressions in adult CPR

    PubMed Central

    2011-01-01

    Chest compressions have saved the lives of countless patients in cardiac arrest as they generate a small but critical amount of blood flow to the heart and brain. This is achieved by direct cardiac massage as well as a thoracic pump mechanism. In order to optimize blood flow excellent chest compression technique is critical. Thus, the quality of the delivered chest compressions is a pivotal determinant of successful resuscitation. If a patient is found unresponsive without a definite pulse or normal breathing then the responder should assume that this patient is in cardiac arrest, activate the emergency response system and immediately start chest compressions. Contra-indications to starting chest compressions include a valid Do Not Attempt Resuscitation Order. Optimal technique for adult chest compressions includes positioning the patient supine, and pushing hard and fast over the center of the chest with the outstretched arms perpendicular to the patient's chest. The rate should be at least 100 compressions per minute and any interruptions should be minimized to achieve a minimum of 60 actually delivered compressions per minute. Aggressive rotation of compressors prevents decline of chest compression quality due to fatigue. Chest compressions are terminated following return of spontaneous circulation. Unconscious patients with normal breathing are placed in the recovery position. If there is no return of spontaneous circulation, then the decision to terminate chest compressions is based on the clinical judgment that the patient's cardiac arrest is unresponsive to treatment. Finally, it is important that family and patients' loved ones who witness chest compressions be treated with consideration and sensitivity. PMID:22152601

  13. Active Thermal Control Experiments for LISA Ground Verification Testing

    NASA Astrophysics Data System (ADS)

    Higuchi, Sei; DeBra, Daniel B.

    2006-11-01

    The primary mission goal of LISA is detecting gravitational waves. LISA uses laser metrology to measure the distance between proof masses in three identical spacecrafts. The total acceleration disturbance to each proof mass is required to be below 3 × 10-15 m/s2√Hz . Optical path length variations on each optical bench must be kept below 40 pm/√Hz over 1 Hz to 0.1 mHz. Thermal variations due to, for example, solar radiation or temperature gradients across the proof mass housing will distort the spacecraft causing changes in the mass attraction and sensor location. We have developed a thermal control system developed for the LISA gravitational reference sensor (GRS) ground verification testing which provides thermal stability better than 1 mK/√Hz to f < 1 mHz and which by extension is suitable for in-flight thermal control for the LISA spacecraft to compensate solar irradiation. Thermally stable environment is very demanded for LISA performance verification. In a lab environment specifications can be met with considerable amount of insulation and thermal mass. For spacecraft, the very limited thermal mass calls for an active control system which can meet disturbance rejection and stability requirements simultaneously in the presence of long time delay. A simple proportional plus integral control law presently provides approximately 1 mK/√Hz of thermal stability for over 80 hours. Continuing development of a model predictive feed-forward algorithm will extend performance to below 1 mK/√Hz at f < 1 mHz and lower.

  14. HIPPARCOS satellite: Aeritalia involvement and system test activities and results

    NASA Astrophysics Data System (ADS)

    Strim, B.; Cugno, W.; Morsillo, G.

    In 1989 the European Space Agency is scheduled to launch HIPPARCOS on a 2.5-year mission that will revolutionize the state of astronomy. This is the first satellite to be dedicated to astrometry, a branch of astronomy that deals with the position of celestial objects and their motion in space. With an accuracy impossible to achieve from Earth, HIPPARCOS will make position, trigonometric parallax and proper motion measurements of some 100.000 pre-selected stars. The data will be used to calculate each star's distance and motion, providing astronomers with an unprecedented map of the heavens. In the end, the HIPPARCOS mission is expected to reveal surprisingly new insight into theories of stellar evolution, as well as into the nature of our galaxy and the universe. The program has been awarded to the MESH industrial consortium for definition, development and production. The French firm MATRA (prime contractor) and the AERITALIA SPACE SYSTEMS GROUP (major co-contractor) share program responsibility. AERITALIA is in charge of the spacecraft or "service module". This is the structural platform for the telescope payload and provides all subsystem services including thermal control, data handling, telecommunications, electrical power distribution, power generation, attitude and orbit control, and apogee kick motor. AERITALIA is responsible for the procurement of all spacecraft subsystems for which it directs the activities of a multinational team of subcontractors. In addition, it is in charge of the satellite's final assembly, integration and testing, as well as for the procurement of all ground support equipment for satellite testing. HIPPARCOS stands for HIgh Precision PARallax COllecting Satellite. Its name is also intended to honor the Greek astronomer Hipparchus (190-120 BC) who compiled the first star catalog and who first used trigonometric parallax to calculate the distance to the moon. (Parallax is the apparent shift in a celestial body's position in the sky

  15. SIRT1-dependent myoprotective effects of resveratrol on muscle injury induced by compression

    PubMed Central

    Sin, Thomas K.; Yung, Benjamin Y.; Yip, Shea P.; Chan, Lawrence W.; Wong, Cesar S.; Tam, Eric W.; Siu, Parco M.

    2015-01-01

    Our current understanding on the molecular mechanisms by which sustained compression induces skeletal muscle injury is very limited. This study aimed to test the hypothesis that activation of SIRT1 by the natural antioxidant resveratrol could deactivate apoptotic and catabolic signaling in skeletal muscle exposed to moderate compression. Two cycles of 6-h constant pressure at 100 mmHg was applied to the tibialis region of right, but not left hindlimbs of Sprague Dawley rats pre-treated with DMSO (vehicle control) or resveratrol with/without sirtinol. Skeletal muscle tissues lying underneath and spatially corresponding to the compressed sites were collected for analyses. Resveratrol prevented the compression-induced manifestations of pathohistological damages including elevations of the number of interstitial nuclei and area of interstitial space and ameliorated oxidative damages measured as 4-hydroxy-2-nonenal (4HNE) and nitrotyrosine in skeletal muscle. In parallel, resveratrol augmented the expression level and activity of SIRT1 and phosphorylation levels of Foxo3a and Akt while suppressed the increases in protein abundances of p53, Bax, MAFbx, and ubiquitin, enzymatic activities of caspase 3 and 20S proteasome, and apoptotic DNA fragmentation in the compressed muscle. These favorable myoprotective effects of resveratrol were diminished upon pharmacological blockade of SIRT1 by using sirtinol. These novel data support the hypothesis that the anti-apoptotic and anti-catabolic effects of resveratrol on compression injury in skeletal muscle required the action of SIRT1. PMID:26557094

  16. Compression evaluation of surgery video recordings retaining diagnostic credibility (compression evaluation of surgery video)

    NASA Astrophysics Data System (ADS)

    Duplaga, M.; Leszczuk, M. I.; Papir, Z.; Przelaskowski, A.

    2008-12-01

    Wider dissemination of medical digital video libraries is affected by two correlated factors, resource effective content compression that directly influences its diagnostic credibility. It has been proved that it is possible to meet these contradictory requirements halfway for long-lasting and low motion surgery recordings at compression ratios close to 100 (bronchoscopic procedures were a case study investigated). As the main supporting assumption, it has been accepted that the content can be compressed as far as clinicians are not able to sense a loss of video diagnostic fidelity (a visually lossless compression). Different market codecs were inspected by means of the combined subjective and objective tests toward their usability in medical video libraries. Subjective tests involved a panel of clinicians who had to classify compressed bronchoscopic video content according to its quality under the bubble sort algorithm. For objective tests, two metrics (hybrid vector measure and hosaka Plots) were calculated frame by frame and averaged over a whole sequence.

  17. Electrorheological fluid under elongation, compression, and shearing

    NASA Astrophysics Data System (ADS)

    Tian, Y.; Meng, Y.; Mao, H.; Wen, S.

    2002-03-01

    Electrorheological (ER) fluid based on zeolite and silicone oil under elongation, compression, and shearing was investigated at room temperature. Dc electric fields were applied on the ER fluid when elongation and compression were carried out on a self-constructed test system. The shear yield stress, presenting the macroscopic interactions of particles in the ER fluid along the direction of shearing and perpendicular to the direction of the electric field, was also obtained by a HAAKE RV20 rheometer. The tensile yield stress, presenting the macroscopic interactions of particles in the ER fluid along the direction of the electric field, was achieved as the peak value in the elongating curve with an elongating yield strain of 0.15-0.20. A shear yield angle of about 15°-18.5° reasonably connected tensile yield stress with shear yield stress, agreeing with the shear yield angle tested well by other researchers. The compressing tests showed that the ER fluid has a high compressive modulus under a small compressive strain lower than 0.1. The compressive stress has an exponential relationship with the compressive strain when it is higher than 0.1, and it is much higher than shear yield stress.

  18. Compression behavior of unidirectional fibrous composite

    NASA Technical Reports Server (NTRS)

    Sinclair, J. H.; Chamis, C. C.

    1982-01-01

    The longitudinal compression behavior of unidirectional fiber composites is investigated using a modified Celanese test method with thick and thin test specimens. The test data obtained are interpreted using the stress/strain curves from back-to-back strain gages, examination of fracture surfaces by scanning electron microscope, and predictive equations for distinct failure modes including fiber compression failure, Euler buckling, delamination, and flexure. The results show that the longitudinal compression fracture is induced by a combination of delamination, flexure, and fiber tier breaks. No distinct fracture surface characteristics can be associated with unique failure modes. An equation is described which can be used to extract the longitudinal compression strength knowing the longitudinal tensile and flexural strengths of the same composite system.

  19. Compressive behavior of unidirectional fibrous composites

    NASA Technical Reports Server (NTRS)

    Sinclair, J. H.; Chamis, C. C.

    1983-01-01

    The longitudinal compressive behavior of unidirectional fiber composites was investigated by using the Illinois Institute of Technology Research Institute (IITRI) test method with thick and thin test specimens. The test data obtained are interpreted by means of stress/strain curves from back-to-back strain gages, examination of fracture surfaces by scanning electron microscope, and predictive equations for distinct failure modes including fiber compression failure. Euler buckling, delamination, and flexure. The results show that longitudinal compressive fracture is induced by a combination of delamination, flexure, and fiber tier breaks. No distinct fracture surface characteristics can be associated with unique failure modes. An equation is described that can be used to extract the longitudinal compressive strength from the longitudinal tensile and flexural strengths of the same composite system.

  20. Fabrication of graded density impactor via underwater shock wave and quasi-isentropic compression testing at two-stage gas gun facility

    NASA Astrophysics Data System (ADS)

    Sun, Wei; Li, Xiaojie; Hokamoto, Kazuyuki

    2014-12-01

    We show direct evidence that underwater shock wave enables us to bond multithin plates with flat, parallel, and high-strength interfaces, which are key requirements for functionally graded material (also called graded density impactor). This phenomenon is ascribed to the super short duration of the high-speed underwater shock wave, reducing the surface tension, diffusion, evaporation, deposition, and viscous flow of matter. Thin magnesium, aluminum, titanium, copper, and molybdenum foils were welded together and designed with the increase in density. Experimental evidence and numerical simulation show that well bonding between the multilayer structures. Microstructure examinations reveal that the dominant interfacial form shifts from waviness to linearity. Graded density impactor with multilayer structure is proved that can produce quasi-isentropic compression in two-stage gas gun experiment with a designed pressure loading profile, which suggests a feasible method to simulate the conditions we want to study that were previously inaccessible in a precisely controlled laboratory environment.

  1. Reduced oxide soldering activation (ROSA) PWB solderability testing

    SciTech Connect

    Hernandez, C.L.; Hosking, F.M.; Reed, J.; Tench, D.M.; White, J.

    1996-02-01

    The effect of ROSA pretreatment on the solderability of environmentally stressed PWB test coupons was investigated. The PWB surface finish was an electroplated, reflowed solder. Test results demonstrated the ability to recover plated-through-hole fill of steam aged samples with solder after ROSA processing. ROSA offers an alternative method for restoring the solderability of aged PWB surfaces.

  2. Comparison of Artificial Compressibility Methods

    NASA Technical Reports Server (NTRS)

    Kiris, Cetin; Housman, Jeffrey; Kwak, Dochan

    2003-01-01

    Various artificial compressibility methods for calculating three-dimensional, steady and unsteady, laminar and turbulent, incompressible Navier-Stokes equations are compared in this work. Each method is described in detail along with appropriate physical and numerical boundary conditions. Analysis of well-posedness and numerical solutions to test problems for each method are provided. A comparison based on convergence behavior, accuracy, stability and robustness is used to establish the relative positive and negative characteristics of each method.

  3. A New Compression Method for FITS Tables

    NASA Technical Reports Server (NTRS)

    Pence, William; Seaman, Rob; White, Richard L.

    2010-01-01

    As the size and number of FITS binary tables generated by astronomical observatories increases, so does the need for a more efficient compression method to reduce the amount disk space and network bandwidth required to archive and down1oad the data tables. We have developed a new compression method for FITS binary tables that is modeled after the FITS tiled-image compression compression convention that has been in use for the past decade. Tests of this new method on a sample of FITS binary tables from a variety of current missions show that on average this new compression technique saves about 50% more disk space than when simply compressing the whole FITS file with gzip. Other advantages of this method are (1) the compressed FITS table is itself a valid FITS table, (2) the FITS headers remain uncompressed, thus allowing rapid read and write access to the keyword values, and (3) in the common case where the FITS file contains multiple tables, each table is compressed separately and may be accessed without having to uncompress the whole file.

  4. Insertion Profiles of 4 Headless Compression Screws

    PubMed Central

    Hart, Adam; Harvey, Edward J.; Lefebvre, Louis-Philippe; Barthelat, Francois; Rabiei, Reza; Martineau, Paul A.

    2013-01-01

    Purpose In practice, the surgeon must rely on screw position (insertion depth) and tactile feedback from the screwdriver (insertion torque) to gauge compression. In this study, we identified the relationship between interfragmentary compression and these 2 factors. Methods The Acutrak Standard, Acutrak Mini, Synthes 3.0, and Herbert-Whipple implants were tested using a polyurethane foam scaphoid model. A specialized testing jig simultaneously measured compression force, insertion torque, and insertion depth at half-screw-turn intervals until failure occurred. Results The peak compression occurs at an insertion depth of −3.1 mm, −2.8 mm, 0.9 mm, and 1.5 mm for the Acutrak Mini, Acutrak Standard, Herbert-Whipple, and Synthes screws respectively (insertion depth is positive when the screw is proud above the bone and negative when buried). The compression and insertion torque at a depth of −2 mm were found to be 113 ± 18 N and 0.348 ± 0.052 Nm for the Acutrak Standard, 104 ± 15 N and 0.175 ± 0.008 Nm for the Acutrak Mini, 78 ± 9 N and 0.245 ± 0.006 Nm for the Herbert-Whipple, and 67 ± 2N, 0.233 ± 0.010 Nm for the Synthes headless compression screws. Conclusions All 4 screws generated a sizable amount of compression (> 60 N) over a wide range of insertion depths. The compression at the commonly recommended insertion depth of −2 mm was not significantly different between screws; thus, implant selection should not be based on compression profile alone. Conically shaped screws (Acutrak) generated their peak compression when they were fully buried in the foam whereas the shanked screws (Synthes and Herbert-Whipple) reached peak compression before they were fully inserted. Because insertion torque correlated poorly with compression, surgeons should avoid using tactile judgment of torque as a proxy for compression. Clinical relevance Knowledge of the insertion profile may improve our understanding of the implants, provide a better basis for comparing screws

  5. Should soil testing services measure soil biological activity?

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Health of agricultural soils depends largely on conservation management to promote soil organic C accumulation. Total soil organic C changes slowly, but active fractions are more dynamic. A key indicator of healthy soil is potential biological activity, which could be measured rapidly with soil te...

  6. Plutonium recycle test reactor characterization activities and results

    SciTech Connect

    Cornwell, B.C.

    1997-05-01

    Report contains results of PRTR core and associated structures characterization performed in January and February of 1997. Radiation survey data are presented, along with recommendations for stabilization activities before transitioning to a decontamination and decommissioning function. Recommendations are also made about handling the waste generated by the stabilization activities, and actions suggested by the Decontamination and Decommissioning organization.

  7. Advanced Vehicle Testing Activity: Low-Percentage Hydrogen/CNG Blend Ford F-150 Operating Summary - January 2003

    SciTech Connect

    Karner, D.; Francfort, J.E.

    2003-01-22

    Over the past two years, Arizona Public Service, a subsidiary of Pinnacle West Capital Corporation, in cooperation with the U.S. Department of Energy's Advanced Vehicle Testing Activity, tested four gaseous fuel vehicles as part of its alternative fueled vehicle fleet. One vehicle operated initially using compressed natural gas (CNG) and later a blend of CNG and hydrogen. Of the other three vehicles, one was fueled with pure hydrogen and two were fueled with a blend of CNG and hydrogen. The three blended-fuel vehicles were originally equipped with either factory CNG engines or factory gasoline engines that were converted to run CNG fuel. The vehicles were variously modified to operate on blended fuel and were tested using 15 to 50% blends of hydrogen (by volume). The pure-hydrogen-fueled vehicle was converted from gasoline fuel to operate on 100% hydrogen. All vehicles were fueled from the Arizona Public Service's Alternative Fuel Pilot Plant, which was developed to dispense gaseous fuels, including CNG, blends of CNG and hydrogen, and pure hydrogen with up to 99.9999% purity. The primary objective of the test was to evaluate the safety and reliability of operating vehicles on hydrogen and blended hydrogen fuel, and the interface between the vehicles and the hydrogen fueling infrastructure. A secondary objective was to quantify vehicle emissions, cost, and performance. Over a total of 40,000 fleet test miles, no safety issues were found. Also, significant reductions in emissions were achieved by adding hydrogen to the fuel. This report presents results of 16,942 miles of testing for one of the blended fuel vehicles, a Ford F-150 pickup truck, operating on up to 30% hydrogen/70% CNG fuel.

  8. Advanced Vehicle Testing Activity: High-Percentage Hydrogen/CNG Blend Ford F-150 Operating Summary - January 2003

    SciTech Connect

    Karner, D.; Francfort, J.E.

    2003-01-22

    Over the past two years, Arizona Public Service, a subsidiary of Pinnacle West Capital Corporation, in cooperation with the U.S. Department of Energy's Advanced Vehicle Testing Activity, tested four gaseous fuel vehicles as part of its alternative fueled vehicle fleet. One vehicle operated initially using compressed natural gas (CNG) and later a blend of CNG and hydrogen. Of the other three vehicles, one was fueled with pure hydrogen and two were fueled with a blend of CNG and hydrogen. The three blended-fuel vehicles were originally equipped with either factory CNG engines or factory gasoline engines that were converted to run CNG fuel. The vehicles were variously modified to operate on blended fuel and were tested using 15 to 50% blends of hydrogen (by volume). The pure-hydrogen-fueled vehicle was converted from gasoline fuel to operate on 100% hydrogen. All vehicles were fueled from the Arizona Public Service's Alternative Fuel Pilot Plant, which was developed to dispense gaseous fuels, including CNG, blends of CNG and hydrogen, and pure hydrogen with up to 99.9999% purity. The primary objective of the test was to evaluate the safety and reliability of operating vehicles on hydrogen and blended fuel, and the interface between the vehicles and the hydrogen fueling infrastructure. A secondary objective was to quantify vehicle emissions, cost, and performance. Over a total of 40,000 fleet test miles, no safety issues were found. Also, significant reductions in emissions were achieved by adding hydrogen to the fuel. This report presents the results of 4,695 miles of testing for one of the blended fuel vehicles, a Ford F-150 pickup truck, operating on up to 50% hydrogen-50% CNG fuel.

  9. Manufacturing and thermomechanical testing of actively cooled all beryllium high heat flux test pieces

    SciTech Connect

    Vasiliev, N.N.; Sokolov, Yu.A.; Shatalov, G.E.

    1995-09-01

    One of the problems affiliated to ITER high heat flux elements development is a problem of interface of beryllium protection with heat sink routinely made of copper alloys. To get rid of this problem all beryllium elements could be used as heat receivers in places of enhanced thermal loads. In accordance with this objectives four beryllium test pieces of two types have been manufactured in {open_quotes}Institute of Beryllium{close_quotes} for succeeding thermomechanical testing. Two of them were manufactured in accordance with JET team design; they are round {open_quotes}hypervapotron type{close_quotes} test pieces. Another two ones are rectangular test sections with a twisted tape installed inside of the circular channel. Preliminary stress-strain analysis have been performed for both type of the test pieces. Hypervapotrons have been shipped to JET where they were tested on JET test bed. Thermomechanical testing of pieces of the type of {open_quotes}swirl tape inside of tube{close_quotes} have been performed on Kurchatov Institute test bed. Chosen beryllium grade properties, some details of manufacturing, results of preliminary stress-strain analysis and thermomechanical testing of the test pieces {open_quotes}swirl tape inside of tube{close_quotes} type are given in this report.

  10. 47 CFR 76.1711 - Emergency alert system (EAS) tests and activation.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 4 2010-10-01 2010-10-01 false Emergency alert system (EAS) tests and... § 76.1711 Emergency alert system (EAS) tests and activation. Every cable system of 1,000 or more subscribers shall keep a record of each test and activation of the Emergency Alert System (EAS)...

  11. 47 CFR 76.1711 - Emergency alert system (EAS) tests and activation.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 47 Telecommunication 4 2011-10-01 2011-10-01 false Emergency alert system (EAS) tests and... § 76.1711 Emergency alert system (EAS) tests and activation. Every cable system of 1,000 or more subscribers shall keep a record of each test and activation of the Emergency Alert System (EAS)...

  12. 47 CFR 76.1711 - Emergency alert system (EAS) tests and activation.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 47 Telecommunication 4 2012-10-01 2012-10-01 false Emergency alert system (EAS) tests and... § 76.1711 Emergency alert system (EAS) tests and activation. Every cable system of 1,000 or more subscribers shall keep a record of each test and activation of the Emergency Alert System (EAS)...

  13. 47 CFR 76.1711 - Emergency alert system (EAS) tests and activation.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 47 Telecommunication 4 2014-10-01 2014-10-01 false Emergency alert system (EAS) tests and... § 76.1711 Emergency alert system (EAS) tests and activation. Every cable system of 1,000 or more subscribers shall keep a record of each test and activation of the Emergency Alert System (EAS)...

  14. 47 CFR 76.1711 - Emergency alert system (EAS) tests and activation.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 47 Telecommunication 4 2013-10-01 2013-10-01 false Emergency alert system (EAS) tests and... § 76.1711 Emergency alert system (EAS) tests and activation. Every cable system of 1,000 or more subscribers shall keep a record of each test and activation of the Emergency Alert System (EAS)...

  15. 3M Coban 2 Layer Compression Therapy: Intelligent Compression Dynamics to Suit Different Patient Needs

    PubMed Central

    Bernatchez, Stéphanie F.; Tucker, Joseph; Schnobrich, Ellen; Parks, Patrick J.

    2012-01-01

    Problem Chronic venous insufficiency can lead to recalcitrant leg ulcers. Compression has been shown to be effective in healing these ulcers, but most products are difficult to apply and uncomfortable for patients, leading to inconsistent/ineffective clinical application and poor compliance. In addition, compression presents risks for patients with an ankle-brachial pressure index (ABPI) <0.8 because of the possibility of further compromising the arterial circulation. The ABPI is the ratio of systolic leg blood pressure (taken at ankle) to systolic arm blood pressure (taken above elbow, at brachial artery). This is measured to assess a patient's lower extremity arterial perfusion before initiating compression therapy.1 Solution Using materials science, two-layer compression systems with controlled compression and a low profile were developed. These materials allow for a more consistent bandage application with better control of the applied compression, and their low profile is compatible with most footwear, increasing patient acceptance and compliance with therapy. The original 3M™ Coban™ 2 Layer Compression System is suited for patients with an ABPI ≥0.8; 3M™ Coban™ 2 Layer Lite Compression System can be used on patients with ABPI ≥0.5. New Technology Both compression systems are composed of two layers that combine to create an inelastic sleeve conforming to the limb contour to provide a consistent proper pressure profile to reduce edema. In addition, they slip significantly less than other compression products and improve patient daily living activities and physical symptoms. Indications for Use Both compression systems are indicated for patients with venous leg ulcers, lymphedema, and other conditions where compression therapy is appropriate. Caution As with any compression system, caution must be used when mixed venous and arterial disease is present to not induce any damage. These products are not indicated when the ABPI is <0.5. PMID:24527315

  16. [Medical image compression: a review].

    PubMed

    Noreña, Tatiana; Romero, Eduardo

    2013-01-01

    Modern medicine is an increasingly complex activity , based on the evidence ; it consists of information from multiple sources : medical record text , sound recordings , images and videos generated by a large number of devices . Medical imaging is one of the most important sources of information since they offer comprehensive support of medical procedures for diagnosis and follow-up . However , the amount of information generated by image capturing gadgets quickly exceeds storage availability in radiology services , generating additional costs in devices with greater storage capacity . Besides , the current trend of developing applications in cloud computing has limitations, even though virtual storage is available from anywhere, connections are made through internet . In these scenarios the optimal use of information necessarily requires powerful compression algorithms adapted to medical activity needs . In this paper we present a review of compression techniques used for image storage , and a critical analysis of them from the point of view of their use in clinical settings. PMID:23715317

  17. Effect of Lower Body Compression Garments on Hemodynamics in Response to Running Session

    PubMed Central

    Venckūnas, Tomas; Trinkūnas, Eugenijus; Kamandulis, Sigitas; Poderys, Jonas; Grūnovas, Albinas; Brazaitis, Marius

    2014-01-01

    Purpose. Compression garments are often worn during exercise and allegedly have ergogenic and/or physiological effects. In this study, we compared hemodynamics and running performance while wearing compression and loose-fit breeches. We hypothesized that in neutral-warm environment compression breeches impair performance by diminishing body cooling via evaporative sweat loss and redistributing blood from active musculature to skin leading to a larger rise in body temperature and prolonging recovery of hemodynamics after exercise. Methods. Changes in hemodynamics (leg blood flow, heart rate, and blood pressure during orthoclinostatic test), calf muscle tissue oxygenation, and skin and core temperatures were measured in response to 30 min running (simulation of aerobic training session) followed by maximal 400 m sprint (evaluation of running performance) in recreationally active females (25.1 ± 4.2 yrs; 63.0 ± 8.6 kg) wearing compression or loose-fit breeches in randomized fashion. Results. Wearing compression breeches resulted in larger skin temperature rise under the garment during exercise and recovery (by about 1°C, P < 0.05; statistical power > 85%), while core temperature dynamics and other measured parameters including circulation, running performance, and sensations were similar compared to wearing loose-fit breeches (P > 0.05). Conclusion. Compared with loose-fit breeches, compression breeches have neither positive nor negative physiological and performance effects for females running in thermoneutral environment. PMID:25202721

  18. 21 CFR 864.7140 - Activated whole blood clotting time tests.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Activated whole blood clotting time tests. 864....7140 Activated whole blood clotting time tests. (a) Identification. An activated whole blood clotting... pulmonary embolism by measuring the coagulation time of whole blood. (b) Classification. Class...

  19. 21 CFR 864.7140 - Activated whole blood clotting time tests.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Activated whole blood clotting time tests. 864....7140 Activated whole blood clotting time tests. (a) Identification. An activated whole blood clotting... pulmonary embolism by measuring the coagulation time of whole blood. (b) Classification. Class...

  20. 21 CFR 864.7140 - Activated whole blood clotting time tests.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Activated whole blood clotting time tests. 864....7140 Activated whole blood clotting time tests. (a) Identification. An activated whole blood clotting... pulmonary embolism by measuring the coagulation time of whole blood. (b) Classification. Class...

  1. Compressing TV-image data

    NASA Technical Reports Server (NTRS)

    Hilbert, E. E.; Lee, J.; Rice, R. F.; Schlutsmeyer, A. P.

    1981-01-01

    Compressing technique calculates activity estimator for each segment of image line. Estimator is used in conjunction with allowable bits per line, N, to determine number of bits necessary to code each segment and which segments can tolerate truncation. Preprocessed line data are then passed to adaptive variable-length coder, which selects optimum transmission code. Method increases capacity of broadcast and cable television transmissions and helps reduce size of storage medium for video and digital audio recordings.

  2. Friction of Compression-ignition Engines

    NASA Technical Reports Server (NTRS)

    Moore, Charles S; Collins, John H , Jr

    1936-01-01

    The cost in mean effective pressure of generating air flow in the combustion chambers of single-cylinder compression-ignition engines was determined for the prechamber and the displaced-piston types of combustion chamber. For each type a wide range of air-flow quantities, speeds, and boost pressures was investigated. Supplementary tests were made to determine the effect of lubricating-oil temperature, cooling-water temperature, and compression ratio on the friction mean effective pressure of the single-cylinder test engine. Friction curves are included for two 9-cylinder, radial, compression-ignition aircraft engines. The results indicate that generating the optimum forced air flow increased the motoring losses approximately 5 pounds per square inch mean effective pressure regardless of chamber type or engine speed. With a given type of chamber, the rate of increase in friction mean effective pressure with engine speed is independent of the air-flow speed. The effect of boost pressure on the friction cannot be predicted because the friction was decreased, unchanged, or increased depending on the combustion-chamber type and design details. High compression ratio accounts for approximately 5 pounds per square inch mean effective pressure of the friction of these single-cylinder compression-ignition engines. The single-cylinder test engines used in this investigation had a much higher friction mean effective pressure than conventional aircraft engines or than the 9-cylinder, radial, compression-ignition engines tested so that performance should be compared on an indicated basis.

  3. Risk-informed inservice test activities at the NRC

    SciTech Connect

    Fischer, D.; Cheok, M.; Hsia, A.

    1996-12-01

    The operational readiness of certain safety-related components is vital to the safe operation of nuclear power plants. Inservice testing (IST) is one of the mechanisms used by licensees to ensure this readiness. In the past, the type and frequency of IST have been based on the collective best judgment of the NRC and industry in an ASME Code consensus process and NRC rulemaking process. Furthermore, IST requirements have not explicitly considered unique component and system designs and contribution to overall plant risk. Because of the general nature of ASME Code test requirements and non-reliance on risk estimates, current IST requirements may not adequately emphasize testing those components that are most important to safety and may overly emphasize testing of less safety significant components. Nuclear power plant licensees are currently interested in optimizing testing by applying resources in more safety significant areas and, where appropriate, reducing measures in less safety-significant areas. They are interested in maintaining system availability and reducing overall maintenance costs in ways that do not adversely affect safety. The NRC has been interested in using probabilistic, as an adjunct to deterministic, techniques to help define the scope, type and frequency of IST. The development of risk-informed IST programs has the potential to optimize the use of NRC and industry resources without adverse affect on safety.

  4. Solar Energy Education. Home economics: student activities. Field test edition

    SciTech Connect

    Not Available

    1981-03-01

    A view of solar energy from the standpoint of home economics is taken in this book of activities. Students are provided information on solar energy resources while performing these classroom activities. Instructions for the construction of a solar food dryer and a solar cooker are provided. Topics for study include window treatments, clothing, the history of solar energy, vitamins from the sun, and how to choose the correct solar home. (BCS)

  5. TESTING GUIDELINES FOR TECHNETIUM-99 ABSORPTION ON ACTIVATED CARBON

    SciTech Connect

    BYRNES ME

    2010-09-08

    CH2M HILL Plateau Remediation Company (CHPRC) is currently evaluating the potential use of activated carbon adsorption for removing technetium-99 from groundwater as a treatment method for the Hanford Site's 200 West Area groundwater pump-and-treat system. The current pump-and-treat system design will include an ion-exchange (IX) system for selective removal of technetium-99 from selected wells prior to subsequent treatment of the water in the central treatment system. The IX resin selected for technetium-99 removal is Purolite A530E. The resin service life is estimated to be approximately 66.85 days at the design technetium-99 loading rate, and the spent resin must be replaced because it cannot be regenerated. The resulting operating costs associated with resin replacement every 66.85 days are estimated at $0.98 million/year. Activated carbon pre-treatment is being evaluated as a potential cost-saving measure to offset the high operating costs associated with frequent IX resin replacement. This document is preceded by the Literature Survey of Technetium-99 Groundwater Pre-Treatment Option Using Granular Activated Carbon (SGW-43928), which identified and evaluated prior research related to technetium-99 adsorption on activated carbon. The survey also evaluated potential operating considerations for this treatment approach for the 200 West Area. The preliminary conclusions of the literature survey are as follows: (1) Activated carbon can be used to selectively remove technetium-99 from contaminated groundwater. (2) Technetium-99 adsorption onto activated carbon is expected to vary significantly based on carbon types and operating conditions. For the treatment approach to be viable at the Hanford Site, activated carbon must be capable of achieving a designated minimum technetium-99 uptake. (3) Certain radionuclides known to be present in 200 West Area groundwater are also likely to adsorb onto activated carbon. (4) Organic solvent contaminants of concern (COCs) will

  6. Fractal image compression

    NASA Technical Reports Server (NTRS)

    Barnsley, Michael F.; Sloan, Alan D.

    1989-01-01

    Fractals are geometric or data structures which do not simplify under magnification. Fractal Image Compression is a technique which associates a fractal to an image. On the one hand, the fractal can be described in terms of a few succinct rules, while on the other, the fractal contains much or all of the image information. Since the rules are described with less bits of data than the image, compression results. Data compression with fractals is an approach to reach high compression ratios for large data streams related to images. The high compression ratios are attained at a cost of large amounts of computation. Both lossless and lossy modes are supported by the technique. The technique is stable in that small errors in codes lead to small errors in image data. Applications to the NASA mission are discussed.

  7. Do Collaborative Practical Tests Encourage Student-Centered Active Learning of Gross Anatomy?

    ERIC Educational Resources Information Center

    Green, Rodney A.; Cates, Tanya; White, Lloyd; Farchione, Davide

    2016-01-01

    Benefits of collaborative testing have been identified in many disciplines. This study sought to determine whether collaborative practical tests encouraged active learning of anatomy. A gross anatomy course included a collaborative component in four practical tests. Two hundred and seven students initially completed the test as individuals and…

  8. [The importance of using biological test objects in studying the toxicity of surface-active substances].

    PubMed

    Mudryĭ, I V; Debrivnaia, I E

    1996-01-01

    The Azotobacter agilis [correction of azobacter agile] culture appeared to be the most sensitive one among the studied test objects. Buckwheat as a test plant can be recommended in studying the toxicity of surface-active substances. PMID:9035856

  9. Fast lossless compression via cascading Bloom filters

    PubMed Central

    2014-01-01

    Background Data from large Next Generation Sequencing (NGS) experiments present challenges both in terms of costs associated with storage and in time required for file transfer. It is sometimes possible to store only a summary relevant to particular applications, but generally it is desirable to keep all information needed to revisit experimental results in the future. Thus, the need for efficient lossless compression methods for NGS reads arises. It has been shown that NGS-specific compression schemes can improve results over generic compression methods, such as the Lempel-Ziv algorithm, Burrows-Wheeler transform, or Arithmetic Coding. When a reference genome is available, effective compression can be achieved by first aligning the reads to the reference genome, and then encoding each read using the alignment position combined with the differences in the read relative to the reference. These reference-based methods have been shown to compress better than reference-free schemes, but the alignment step they require demands several hours of CPU time on a typical dataset, whereas reference-free methods can usually compress in minutes. Results We present a new approach that achieves highly efficient compression by using a reference genome, but completely circumvents the need for alignment, affording a great reduction in the time needed to compress. In contrast to reference-based methods that first align reads to the genome, we hash all reads into Bloom filters to encode, and decode by querying the same Bloom filters using read-length subsequences of the reference genome. Further compression is achieved by using a cascade of such filters. Conclusions Our method, called BARCODE, runs an order of magnitude faster than reference-based methods, while compressing an order of magnitude better than reference-free methods, over a broad range of sequencing coverage. In high coverage (50-100 fold), compared to the best tested compressors, BARCODE saves 80-90% of the running time

  10. Shuttle active thermal control system development testing. Volume 7: Improved radiator coating adhesive tests

    NASA Technical Reports Server (NTRS)

    Reed, M. W.

    1973-01-01

    Silver/Teflon thermal control coatings have been tested on a modular radiator system projected for use on the space shuttle. Seven candidate adhesives have been evaluated in a thermal vacuum test on radiator panels similar to the anticipated flight hardware configuration. Several classes of adhesives based on polyester, silicone, and urethane resin systems were tested. These included contact adhesives, heat cured adhesives, heat and pressure cured adhesives, pressure sensitive adhesives, and two part paint on or spray on adhesives. The coatings attached with four of the adhesives, two silicones and two urethanes, had no changes develop during the thermal vacuum test. The two silicone adhesives, both of which were applied to the silver/Teflon as transfer laminates to form a tape, offered the most promise based on application process and thermal performance. Each of the successful silicone adhesives required a heat and pressure cure to adhere during the cryogenic temperature excursion of the thermal-vacuum test.

  11. 49 CFR 173.302b - Additional requirements for shipment of non-liquefied (permanent) compressed gases in UN pressure...

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... may the internal pressure at 65 °C (149 °F) exceed the test pressure. (c) Fluorine, compressed, UN 1045 and Oxygen difluoride, compressed, UN 2190. Fluorine, compressed and Oxygen difluoride,...

  12. 49 CFR 173.302b - Additional requirements for shipment of non-liquefied (permanent) compressed gases in UN pressure...

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... may the internal pressure at 65 °C (149 °F) exceed the test pressure. (c) Fluorine, compressed, UN 1045 and Oxygen diflouride, compressed, UN 2190. Fluorine, compressed and Oxygen difluoride,...

  13. 49 CFR 173.302b - Additional requirements for shipment of non-liquefied (permanent) compressed gases in UN pressure...

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... may the internal pressure at 65 °C (149 °F) exceed the test pressure. (c) Fluorine, compressed, UN 1045 and Oxygen difluoride, compressed, UN 2190. Fluorine, compressed and Oxygen difluoride,...

  14. 49 CFR 173.302b - Additional requirements for shipment of non-liquefied (permanent) compressed gases in UN pressure...

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... may the internal pressure at 65 °C (149 °F) exceed the test pressure. (c) Fluorine, compressed, UN 1045 and Oxygen difluoride, compressed, UN 2190. Fluorine, compressed and Oxygen difluoride,...

  15. 49 CFR 173.302b - Additional requirements for shipment of non-liquefied (permanent) compressed gases in UN pressure...

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... may the internal pressure at 65 °C (149 °F) exceed the test pressure. (c) Fluorine, compressed, UN 1045 and Oxygen diflouride, compressed, UN 2190. Fluorine, compressed and Oxygen difluoride,...

  16. 78 FR 30899 - Agency Information Collection Activities; Comment Request; NCES Cognitive, Pilot, and Field Test...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-05-23

    ... and methodologies. The procedures utilized to this effect include but are not limited to experiments... activities, pilot testing, exploratory interviews, experiments with questionnaire design, and...

  17. Solar Energy Education. Industrial arts: student activities. Field test edition

    SciTech Connect

    Not Available

    1981-02-01

    In this teaching manual several activities are presented to introduce students to information on solar energy through classroom instruction. Wind power is also included. Instructions for constructing demonstration models for passive solar systems, photovoltaic cells, solar collectors and water heaters, and a bicycle wheel wind turbine are provided. (BCS)

  18. Testing of actively cooled high heat flux mock-ups

    NASA Astrophysics Data System (ADS)

    Rödig, M.; Duwe, R.; Kühnlein, W.; Linke, J.; Scheerer, M.; Smid, I.; Wiechers, B.

    1998-10-01

    Several un-irradiated CFC monoblock mock-ups have been loaded in thermal fatigue tests up to 1000 cycles at power densities <25 MW/m 2. No indication of failure was observed for these loading conditions. Two of the mock-ups were inspected by ultra-sonic methods before thermal cycling. It could be proved that the voids found in the post-mortem metallography existed before and had no effect on the integrity of the mock-up. For the first time, neutron-irradiated CFC monoblock mock-ups have been tested in the electron beam facility JUDITH. These mock-ups had been irradiated before in the High Flux Reactor at Petten up to 0.3 dpa at 320°C and 770°C. All samples showed a significant increase of surface temperature, due to the irradiation induced decrease in thermal conductivity of the CFC materials.

  19. The Clinically Tested Gardos Channel Inhibitor Senicapoc Exhibits Antimalarial Activity

    PubMed Central

    Tubman, Venée N.; Mejia, Pedro; Shmukler, Boris E.; Bei, Amy K.; Alper, Seth L.; Mitchell, James R.

    2015-01-01

    Senicapoc, a Gardos channel inhibitor, prevented erythrocyte dehydration in clinical trials of patients with sickle cell disease. We tested the hypothesis that senicapoc-induced blockade of the Gardos channel inhibits Plasmodium growth. Senicapoc inhibited in vitro growth of human and primate plasmodia during the clinical blood stage. Senicapoc treatment suppressed P. yoelii parasitemia in vivo in C57BL/6 mice. The reassuring safety and biochemical profile of senicapoc encourage its use in antimalarial development. PMID:26459896

  20. Compressing bitmap indexes for faster search operations

    SciTech Connect

    Wu, Kesheng; Otoo, Ekow J.; Shoshani, Arie

    2002-04-25

    In this paper, we study the effects of compression on bitmap indexes. The main operations on the bitmaps during query processing are bitwise logical operations such as AND, OR, NOT, etc. Using the general purpose compression schemes, such as gzip, the logical operations on the compressed bitmaps are much slower than on the uncompressed bitmaps. Specialized compression schemes, like the byte-aligned bitmap code(BBC), are usually faster in performing logical operations than the general purpose schemes, but in many cases they are still orders of magnitude slower than the uncompressed scheme. To make the compressed bitmap indexes operate more efficiently, we designed a CPU-friendly scheme which we refer to as the word-aligned hybrid code (WAH). Tests on both synthetic and real application data show that the new scheme significantly outperforms well-known compression schemes at a modest increase in storage space. Compared to BBC, a scheme well-known for its operational efficiency, WAH performs logical operations about 12 times faster and uses only 60 percent more space. Compared to the uncompressed scheme, in most test cases WAH is faster while still using less space. We further verified with additional tests that the improvement in logical operation speed translates to similar improvement in query processing speed.

  1. On the Compressibility of Arterial Tissue.

    PubMed

    Nolan, D R; McGarry, J P

    2016-04-01

    Arterial tissue is commonly assumed to be incompressible. While this assumption is convenient for both experimentalists and theorists, the compressibility of arterial tissue has not been rigorously investigated. In the current study we present an experimental-computational methodology to determine the compressibility of aortic tissue and we demonstrate that specimens excised from an ovine descending aorta are significantly compressible. Specimens are stretched in the radial direction in order to fully characterise the mechanical behaviour of the tissue ground matrix. Additionally biaxial testing is performed to fully characterise the anisotropic contribution of reinforcing fibres. Due to the complexity of the experimental tests, which entail non-uniform finite deformation of a non-linear anisotropic material, it is necessary to implement an inverse finite element analysis scheme to characterise the mechanical behaviour of the arterial tissue. Results reveal that ovine aortic tissue is highly compressible; an effective Poisson's ratio of 0.44 is determined for the ground matrix component of the tissue. It is also demonstrated that correct characterisation of material compressibility has important implications for the calibration of anisotropic fibre properties using biaxial tests. Finally it is demonstrated that correct treatment of material compressibility has significant implications for the accurate prediction of the stress state in an artery under in vivo type loading. PMID:26297340

  2. Comparison of Open-Hole Compression Strength and Compression After Impact Strength on Carbon Fiber/Epoxy Laminates for the Ares I Composite Interstage

    NASA Technical Reports Server (NTRS)

    Hodge, Andrew J.; Nettles, Alan T.; Jackson, Justin R.

    2011-01-01

    Notched (open hole) composite laminates were tested in compression. The effect on strength of various sizes of through holes was examined. Results were compared to the average stress criterion model. Additionally, laminated sandwich structures were damaged from low-velocity impact with various impact energy levels and different impactor geometries. The compression strength relative to damage size was compared to the notched compression result strength. Open-hole compression strength was found to provide a reasonable bound on compression after impact.

  3. Recovery Efficiency Test Project: Phase 1, Activity report

    SciTech Connect

    Overbey, W.K. Jr.; Carden, R.S.; Kirr, J.N.

    1987-04-01

    The recovery Efficiency Test well project addressed a number of technical issues. The primary objective was to determine the increased efficiency gas recovery of a long horizontal wellbore over that of a vertical wellbore and, more specifically, what improvements can be expected from inducing multiple hydraulic fractures from such a wellbore. BDM corporation located, planned, and drilled a long radius turn horizontal well in the Devonian shale Lower Huron section in Wayne County, West Virginia, demonstrating that state-of-the-art technology is capable of drilling such wells. BDM successfully tested drilling, coring, and logging in a horizontal well using air as the circulating medium; conducted reservoir modeling studies to protect flow rates and reserves in advance of drilling operations; observed two phase flow conditions in the wellbore not observed previously; cored a fracture zone which produced gas; observed that fractures in the core and the wellbore were not systematically spaced (varied from 5 to 68 feet in different parts of the wellbore); observed that highest gas show rates reported by the mud logger corresponded to zone with lowest fracture spacing (five feet) or high fracture frequency. Four and one-half inch casting was successfully installed in the borehole and was equipped to isolate the horizontal section into eight (8) zones for future testing and stimulation operations. 6 refs., 48 figs., 10 tabs.

  4. Extra-Vehicular Activity (EVA) glove evaluation test protocol

    NASA Technical Reports Server (NTRS)

    Hinman-Sweeney, E. M.

    1994-01-01

    One of the most critical components of a space suit is the gloves, yet gloves have traditionally presented significant design challenges. With continued efforts at glove development, a method for evaluating glove performance is needed. This paper presents a pressure-glove evaluation protocol. A description of this evaluation protocol, and its development is provided. The protocol allows comparison of one glove design to another, or any one design to bare-handed performance. Gloves for higher pressure suits may be evaluated at current and future design pressures to drive out differences in performance due to pressure effects. Using this protocol, gloves may be evaluated during design to drive out design problems and determine areas for improvement, or fully mature designs may be evaluated with respect to mission requirements. Several different test configurations are presented to handle these cases. This protocol was run on a prototype glove. The prototype was evaluated at two operating pressures and in the unpressurized state, with results compared to bare-handed performance. Results and analysis from this test series are provided, as is a description of the configuration used for this test.

  5. EEG data compression techniques.

    PubMed

    Antoniol, G; Tonella, P

    1997-02-01

    In this paper, electroencephalograph (EEG) and Holter EEG data compression techniques which allow perfect reconstruction of the recorded waveform from the compressed one are presented and discussed. Data compression permits one to achieve significant reduction in the space required to store signals and in transmission time. The Huffman coding technique in conjunction with derivative computation reaches high compression ratios (on average 49% on Holter and 58% on EEG signals) with low computational complexity. By exploiting this result a simple and fast encoder/decoder scheme capable of real-time performance on a PC was implemented. This simple technique is compared with other predictive transformations, vector quantization, discrete cosine transform (DCT), and repetition count compression methods. Finally, it is shown that the adoption of a collapsed Huffman tree for the encoding/decoding operations allows one to choose the maximum codeword length without significantly affecting the compression ratio. Therefore, low cost commercial microcontrollers and storage devices can be effectively used to store long Holter EEG's in a compressed format. PMID:9214790

  6. Geomechanical Risk Assessment on Shear Activation of Faults in the CO2 Storage Test Site, Offshore Pohang, South Korea

    NASA Astrophysics Data System (ADS)

    Jo, Y.; Chang, C.; Shinn, Y. J.; Song, I.; Kwon, Y. K.

    2015-12-01

    A pilot CO2 sequestration test project is underway in offshore Pohang, South Korea. The target brine aquifer for CO2 storage is 100 m-thick sandstone/conglomerate formations at a depth range between 750 and 850 mbsf (meter below seafloor), which were verified by a 3D seismic survey and a cored borehole (980 m deep). We also found that a family of steep-dip, NE-striking faults cross the target aquifer. In order to analyze potential risk of shear activation along the faults, we characterize in situ stress state at the site. Borehole image logs, generated by an acoustic televiewer tool showed borehole breakouts along the whole logged section to ~705 mbsf, which consistently indicate an average maximum horizontal principal stress (SHmax) direction of N135°±15°E. A leak-off test conducted at the bottom of a casing shoe (700 mbsf) yielded the magnitude of the minimum horizontal principal stress (Shmin) of 12.1 MPa, which is lower than the vertical stress (Sv =14.8 MPa). For the given Shmin and Sv conditions, we used the logged breakout widths and laboratory determined rock compressive strength to constrain possible SHmax magnitudes that could create the observed breakouts. Our stress estimation indicates that the stress regime in the CO2 injection test site is in favor of strike-slip faulting (Shmin < Sv < SHmax). We utilized our estimated stress conditions to analyze slip tendency of the faults. All regional-scale faults turn out to have relatively low slip tendency under the given stress condition, suggesting a low risk of triggering shear activation of faults during CO2 injection.

  7. Investigation of Cyclic Deformation and Fatigue of Polycrystalline Cu under Pure Compression Cyclic Loading Conditions

    NASA Astrophysics Data System (ADS)

    Hsu, Tzu-Yin Jean

    It is commonly accepted that fatigue crack is initiated under tensile fatigue stresses. However, practical examples demonstrate that cracks may initiate under pure compressive fluctuating loads, e.g. the failures observed in aircraft landing gear frames. As the mechanism of such failures is rarely investigated, there is very limited or non-existent knowledge pool on cyclic deformation response under pure compressive fatigue condition. Our recent work verified that fatigue cracks may nucleate from stress concentration sites under pure compression fatigue, but whether or not a form of stress concentration is always needed to initiate a crack remains uncertain. In this study, compression fatigue tests under different peak stresses were carried out on smooth bars of fully annealed OFHC Copper. The purpose of these tests is to investigate not only the cyclic deformation response but also the possibility of crack nucleation without the stress concentrator. Results showed that overall the cyclic stress-strain response and microstructural evolution of OFHC Copper under pure compression fatigue exhibits rather dissimilar behaviour compared to those under symmetrical fatigue. The specimens hardened rapidly within 10 cycles under pure compression fatigue unlike the gradual cyclic hardening behaviour in symmetrical fatigue with the same peak stress amplitude. Compressive cyclic creep behaviour was also observed. Moreover, TEM observation showed that only moderate slip activity was detectable on the surface instead of typical PSB features. The surface observations revealed that surface slip bands did not increase in number nor height as cycling progressed. In addition, surface roughening by grain boundary extrusion was detected to become more severe with further cycling. Therefore, the plastic strain accommodated within the samples was not mainly related to dislocation activities. Instead, the mechanism of cyclic creep response for pure compression fatigue was correlated and

  8. Boson core compressibility

    NASA Astrophysics Data System (ADS)

    Khorramzadeh, Y.; Lin, Fei; Scarola, V. W.

    2012-04-01

    Strongly interacting atoms trapped in optical lattices can be used to explore phase diagrams of Hubbard models. Spatial inhomogeneity due to trapping typically obscures distinguishing observables. We propose that measures using boson double occupancy avoid trapping effects to reveal two key correlation functions. We define a boson core compressibility and core superfluid stiffness in terms of double occupancy. We use quantum Monte Carlo on the Bose-Hubbard model to empirically show that these quantities intrinsically eliminate edge effects to reveal correlations near the trap center. The boson core compressibility offers a generally applicable tool that can be used to experimentally map out phase transitions between compressible and incompressible states.

  9. Modeling Compressed Turbulence

    SciTech Connect

    Israel, Daniel M.

    2012-07-13

    From ICE to ICF, the effect of mean compression or expansion is important for predicting the state of the turbulence. When developing combustion models, we would like to know the mix state of the reacting species. This involves density and concentration fluctuations. To date, research has focused on the effect of compression on the turbulent kinetic energy. The current work provides constraints to help development and calibration for models of species mixing effects in compressed turbulence. The Cambon, et al., re-scaling has been extended to buoyancy driven turbulence, including the fluctuating density, concentration, and temperature equations. The new scalings give us helpful constraints for developing and validating RANS turbulence models.

  10. Local compressibilities in crystals

    NASA Astrophysics Data System (ADS)

    Martín Pendás, A.; Costales, Aurora; Blanco, M. A.; Recio, J. M.; Luaña, Víctor

    2000-12-01

    An application of the atoms in molecules theory to the partitioning of static thermodynamic properties in condensed systems is presented. Attention is focused on the definition and the behavior of atomic compressibilities. Inverses of bulk moduli are found to be simple weighted averages of atomic compressibilities. Two kinds of systems are investigated as examples: four related oxide spinels and the alkali halide family. Our analyses show that the puzzling constancy of the bulk moduli of these spinels is a consequence of the value of the compressibility of an oxide ion. A functional dependence between ionic bulk moduli and ionic volume is also proposed.

  11. ADVANCED RECIPROCATING COMPRESSION TECHNOLOGY (ARCT)

    SciTech Connect

    Danny M. Deffenbaugh; Klaus Brun; Ralph E. Harris; J. Pete Harrell; Robert J. Mckee; J. Jeffrey Moore; Steven J. Svedeman; Anthony J. Smalley; Eugene L. Broerman; Robert A Hart; Marybeth G. Nored; Ryan S. Gernentz; Shane P. Siebenaler

    2005-12-01

    . Retrofit technologies that address the challenges of slow-speed integral compression are: (1) optimum turndown using a combination of speed and clearance with single-acting operation as a last resort; (2) if single-acting is required, implement infinite length nozzles to address nozzle pulsation and tunable side branch absorbers for 1x lateral pulsations; and (3) advanced valves, either the semi-active plate valve or the passive rotary valve, to extend valve life to three years with half the pressure drop. This next generation of slow-speed compression should attain 95% efficiency, a three-year valve life, and expanded turndown. New equipment technologies that address the challenges of large-horsepower, high-speed compression are: (1) optimum turndown with unit speed; (2) tapered nozzles to effectively reduce nozzle pulsation with half the pressure drop and minimization of mechanical cylinder stretch induced vibrations; (3) tunable side branch absorber or higher-order filter bottle to address lateral piping pulsations over the entire extended speed range with minimal pressure drop; and (4) semi-active plate valves or passive rotary valves to extend valve life with half the pressure drop. This next generation of large-horsepower, high-speed compression should attain 90% efficiency, a two-year valve life, 50% turndown, and less than 0.75 IPS vibration. This program has generated proof-of-concept technologies with the potential to meet these ambitious goals. Full development of these identified technologies is underway. The GMRC has committed to pursue the most promising enabling technologies for their industry.

  12. Compression relief engine brake

    SciTech Connect

    Meneely, V.A.

    1987-10-06

    A compression relief brake is described for four cycle internal-combustion engines, comprising: a pressurized oil supply; means for selectively pressurizing a hydraulic circuit with oil from the oil supply; a master piston and cylinder communicating with a slave piston and cylinder via the hydraulic circuit; an engine exhaust valve mechanically coupled to the engine and timed to open during the exhaust cycle of the engine the exhaust valve coupled to the slave piston. The exhaust valve is spring-based in a closed state to contact a valve seat; a sleeve frictionally and slidably disposed within a cavity defined by the slave piston which cavity communicates with the hydraulic circuit. When the hydraulic circuit is selectively pressurized and the engine is operating the sleeve entraps an incompressible volume of oil within the cavity to generate a displacement of the slave piston within the slave cylinder, whereby a first gap is maintained between the exhaust valve and its associated seat; and means for reciprocally activating the master piston for increasing the pressure within the previously pressurized hydraulic circuit during at least a portion of the expansion cycle of the engine whereby a second gap is reciprocally maintained between the exhaust valve and its associated seat.

  13. Preprototype Vapor Compression Distillation Subsystem development

    NASA Technical Reports Server (NTRS)

    Thompson, C. D.; Ellis, G. S.; Schubert, F. H.

    1981-01-01

    Vapor Compression Distillation (VCD) has evolved as the most promising approach to reclaim potable water from wastewater for future long-term manned space missions. Life Systems, Inc. (LSI), working with NASA, has developed a preprototype Vapor Compression Distillation Subsystem (VCDS) which processes wastewater at 1.4 kg/h. The preprototype unit weighs 143 kg, occupies a volume of 0.47 cu m, and will reclaim 96 percent of the available wastewater. This unit has been tested by LSI and is scheduled for further testing at NASA-JSC. This paper presents the preprototype VCDS design, configuration, performance data, test results and flight system projections.

  14. Flow rate/pressure drop data gathered from testing a sample of the Space Shuttle Strain Isolation Pad (SIP): Effects of ambient pressure combined with tension and compression conditions

    NASA Technical Reports Server (NTRS)

    Springfield, R. D.; Lawing, P. L.

    1983-01-01

    Tests were conducted on a sample of strain isolation pad (SIP) typical of that used in the shuttle orbiter thermal protection system to determine the characteristics of SIP internal flow. Data obtained were pressure drop as a function of flow rate for a range of ambient pressures representing various points along the Shuttle trajectory and for stretched and compressed conditions of the SIP. Flow was in the direction of the weave parallel to most of the fibers. The data are plotted in several standard engineering formats in order to be of maximum utility to the user. In addition to providing support to the Space Shuttle Program, these data are a source of experimental information on flow through fiberous (rather than the more usual sand bed type) porous media.

  15. Further evaluation of the CSNI separate effect test activity

    SciTech Connect

    D`Auria, F.; Aksan, S.N.; Glaeser, H.

    1995-09-01

    An internationally agreed Separate Effect Test (SET) Validation Matrix for the thermalhydraulic system codes has been established by a subgroup of the Task Group on Thermalhydraulic System Behaviour as requested by OECD/NEA Committee on the Safety of Nuclear Installations (CSNI) Principal Working Group No. 2 on Coolant System Behavior. The construction of such matrix constituted an attempt to collect together in a systematic way the best sets of openly available test data to select for code validation. As a final result, 67 phenomena have been identified and characterized, roughly 200 facilities have been considered and more than 1000 experiments have been selected as useful for the validation of the codes. The objective of the present paper is to provide additional evaluation of the obtained data base and to supply an a-posteriori judgement in relation to (a) the data base adequacy, (b) the phenomenon, and (c) the need for additional experiments. This has been provided independently by each of the authors. The main conclusions are that large amount of data are available for certain popular phenomena e.g. heat transfer, but data are severely lacking in more esoteric areas e.g. for characterizing phenomena such as parallel channel instability and boron mixing and transport.

  16. Effects of Instantaneous Multiband Dynamic Compression on Speech Intelligibility

    NASA Astrophysics Data System (ADS)

    Herzke, Tobias; Hohmann, Volker

    2005-12-01

    The recruitment phenomenon, that is, the reduced dynamic range between threshold and uncomfortable level, is attributed to the loss of instantaneous dynamic compression on the basilar membrane. Despite this, hearing aids commonly use slow-acting dynamic compression for its compensation, because this was found to be the most successful strategy in terms of speech quality and intelligibility rehabilitation. Former attempts to use fast-acting compression gave ambiguous results, raising the question as to whether auditory-based recruitment compensation by instantaneous compression is in principle applicable in hearing aids. This study thus investigates instantaneous multiband dynamic compression based on an auditory filterbank. Instantaneous envelope compression is performed in each frequency band of a gammatone filterbank, which provides a combination of time and frequency resolution comparable to the normal healthy cochlea. The gain characteristics used for dynamic compression are deduced from categorical loudness scaling. In speech intelligibility tests, the instantaneous dynamic compression scheme was compared against a linear amplification scheme, which used the same filterbank for frequency analysis, but employed constant gain factors that restored the sound level for medium perceived loudness in each frequency band. In subjective comparisons, five of nine subjects preferred the linear amplification scheme and would not accept the instantaneous dynamic compression in hearing aids. Four of nine subjects did not perceive any quality differences. A sentence intelligibility test in noise (Oldenburg sentence test) showed little to no negative effects of the instantaneous dynamic compression, compared to linear amplification. A word intelligibility test in quiet (one-syllable rhyme test) showed that the subjects benefit from the larger amplification at low levels provided by instantaneous dynamic compression. Further analysis showed that the increase in intelligibility

  17. Lossless Astronomical Image Compression and the Effects of Random Noise

    NASA Technical Reports Server (NTRS)

    Pence, William

    2009-01-01

    In this paper we compare a variety of modern image compression methods on a large sample of astronomical images. We begin by demonstrating from first principles how the amount of noise in the image pixel values sets a theoretical upper limit on the lossless compression ratio of the image. We derive simple procedures for measuring the amount of noise in an image and for quantitatively predicting how much compression will be possible. We then compare the traditional technique of using the GZIP utility to externally compress the image, with a newer technique of dividing the image into tiles, and then compressing and storing each tile in a FITS binary table structure. This tiled-image compression technique offers a choice of other compression algorithms besides GZIP, some of which are much better suited to compressing astronomical images. Our tests on a large sample of images show that the Rice algorithm provides the best combination of speed and compression efficiency. In particular, Rice typically produces 1.5 times greater compression and provides much faster compression speed than GZIP. Floating point images generally contain too much noise to be effectively compressed with any lossless algorithm. We have developed a compression technique which discards some of the useless noise bits by quantizing the pixel values as scaled integers. The integer images can then be compressed by a factor of 4 or more. Our image compression and uncompression utilities (called fpack and funpack) that were used in this study are publicly available from the HEASARC web site.Users may run these stand-alone programs to compress and uncompress their own images.

  18. Rapid toxicity testing based on yeast respiratory activity

    SciTech Connect

    Haubenstricker, M.E. ); Meier, P.G.; Mancy, K.H. ); Brabec, M.J. )

    1990-05-01

    Rapid and economical techniques are needed to determine the effects of environmental contaminants. At present, the main methods to assess the impact of pollutants are based on chemical analysis of the samples. Invertebrate and vertebrate exposures have been used over the last two decades in assessing acute and chronic toxicities. However, these tests are labor intensive and require several days to complete. An alternative to whole organism exposure is to determine toxic effects in monocellular systems. Another approach for assessing toxicity is to monitor sensitive, nonspecific, subcellular target sites such as mitochondria. Changes in mitochondrial function which could indicate a toxic effect can be demonstrated readily after addition of a foreign substance. In initial assessments of various chemicals, rat liver mitochondria (RLM) were evaluated as a biological sensor of toxicity. False toxicity assessments will result if these ions are present even though they are generally considered nontoxic. Because of these disadvantages, an alternative mitochondrial system, such as found in bakers yeast, was evaluated.

  19. Pilot Testing of the Pathway Active Learning Environment

    NASA Astrophysics Data System (ADS)

    Nakamura, Christopher M.; Murphy, Sytil K.; Zollman, Dean A.; Christel, Michael; Stevens, Scott

    2010-10-01

    We present an initial analysis of data taken to test the technical functionality and student usability of an interactive synthetic tutoring system administered online. The system allows students to ask questions and receive prerecorded video responses from knowledgeable tutors in real-time. It logs student interactions with a timestamp and username to generate a time-resolved picture of students' use of the system. The tutoring interaction is structured by lessons covering Newton's laws. Time on-task estimates indicate that students spent about 2.5 hours working through our materials, about as much as intended. Data show students' reluctance to query the tutor or that their focus is on other aspects of the system. This suggests modifications to the system that may encourage students to take advantage of its interactive capabilities. The system combines lessons, images, and video technology designed to emulate conversation to produce a supplemental teaching tool that may be useful for studying multimedia effects on learning.

  20. Compressive Optical Image Encryption

    PubMed Central

    Li, Jun; Sheng Li, Jiao; Yang Pan, Yang; Li, Rong

    2015-01-01

    An optical image encryption technique based on compressive sensing using fully optical means has been proposed. An object image is first encrypted to a white-sense stationary noise pattern using a double random phase encoding (DRPE) method in a Mach-Zehnder interferometer. Then, the encrypted image is highly compressed to a signal using single-pixel compressive holographic imaging in the optical domain. At the receiving terminal, the encrypted image is reconstructed well via compressive sensing theory, and the original image can be decrypted with three reconstructed holograms and the correct keys. The numerical simulations show that the method is effective and suitable for optical image security transmission in future all-optical networks because of the ability of completely optical implementation and substantially smaller hologram data volume. PMID:25992946

  1. Military Data Compression Standard

    NASA Astrophysics Data System (ADS)

    Winterbauer, C. E.

    1982-07-01

    A facsimile interoperability data compression standard is being adopted by the U.S. Department of Defense and other North Atlantic Treaty Organization (NATO) countries. This algorithm has been shown to perform quite well in a noisy communication channel.

  2. Compressive optical image encryption.

    PubMed

    Li, Jun; Sheng Li, Jiao; Yang Pan, Yang; Li, Rong

    2015-01-01

    An optical image encryption technique based on compressive sensing using fully optical means has been proposed. An object image is first encrypted to a white-sense stationary noise pattern using a double random phase encoding (DRPE) method in a Mach-Zehnder interferometer. Then, the encrypted image is highly compressed to a signal using single-pixel compressive holographic imaging in the optical domain. At the receiving terminal, the encrypted image is reconstructed well via compressive sensing theory, and the original image can be decrypted with three reconstructed holograms and the correct keys. The numerical simulations show that the method is effective and suitable for optical image security transmission in future all-optical networks because of the ability of completely optical implementation and substantially smaller hologram data volume. PMID:25992946

  3. Focus on Compression Stockings

    MedlinePlus

    ... sion apparel is used to prevent or control edema The post-thrombotic syndrome (PTS) is a complication ( ... complication. abdomen. This swelling is referred to as edema. If you have edema, compression therapy may be ...

  4. Compressible Astrophysics Simulation Code

    2007-07-18

    This is an astrophysics simulation code involving a radiation diffusion module developed at LLNL coupled to compressible hydrodynamics and adaptive mesh infrastructure developed at LBNL. One intended application is to neutrino diffusion in core collapse supernovae.

  5. Similarity by compression.

    PubMed

    Melville, James L; Riley, Jenna F; Hirst, Jonathan D

    2007-01-01

    We present a simple and effective method for similarity searching in virtual high-throughput screening, requiring only a string-based representation of the molecules (e.g., SMILES) and standard compression software, available on all modern desktop computers. This method utilizes the normalized compression distance, an approximation of the normalized information distance, based on the concept of Kolmogorov complexity. On representative data sets, we demonstrate that compression-based similarity searching can outperform standard similarity searching protocols, exemplified by the Tanimoto coefficient combined with a binary fingerprint representation and data fusion. Software to carry out compression-based similarity is available from our Web site at http://comp.chem.nottingham.ac.uk/download/zippity. PMID:17238245

  6. Advanced Vehicle Testing Activity Cold Weather On-road Testing of the Chevrolet Volt

    SciTech Connect

    Smart, John

    2015-03-01

    This report details cold weather on-road testing of a Chevrolet Volt. It quantifies changes in efficiency and electric range as ambient temperature changes. It will be published to INL's AVTA website as an INL technical report and will be accessible to the general public.

  7. 21 CFR 864.7140 - Activated whole blood clotting time tests.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Activated whole blood clotting time tests. 864.7140 Section 864.7140 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES HEMATOLOGY AND PATHOLOGY DEVICES Hematology Kits and Packages § 864.7140 Activated whole blood clotting time tests....

  8. 21 CFR 864.7140 - Activated whole blood clotting time tests.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Activated whole blood clotting time tests. 864.7140 Section 864.7140 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES HEMATOLOGY AND PATHOLOGY DEVICES Hematology Kits and Packages § 864.7140 Activated whole blood clotting time tests....

  9. Classroom Activity Connections: Demonstrating Various Flame Tests Using Common Household Materials

    ERIC Educational Resources Information Center

    Baldwin, Bruce W.; Hasbrouck, Scott; Smith, Jordan; Kuntzleman, Thomas S.

    2010-01-01

    In "JCE" Activity #67, "Flame Tests: Which Ion Causes the Color?", Michael Sanger describes how to conduct flame tests with household items. We have used this activity in outreach settings, and have extended it in a variety of ways. For example, we have demonstrated large-scale strontium (red), copper (green), and carbon (blue) flames using only…

  10. Synchronous droplets as a test bed for pulsatory active fluids

    NASA Astrophysics Data System (ADS)

    Katsikis, Georgios; Prakash, Manu

    2014-11-01

    Collective behavior in many-body systems has been studied extensively focusing on a wide range of interacting entities including: flocking animals, sedimenting particles and microfluidic droplets among others. Here, we propose an experimental platform to explore an oscillatory active fluid with synchronous ferrofluid droplets immersed in an immiscible carrier fluid in a Hele-Shaw configuration. The droplets are organized and actuated on a 2-D uniform grid through application of a precessive magnetic field. The state of our system is dependent on three parameters: the grid occupancy with fluid droplets, the grid geometry and the magnetic field. We study the long range orientational order of our system over a range of those parameters by tracking the motion of the droplets and analyzing the PIV data of the carrier fluid flow. Numerical simulations are juxtaposed with experimental data for prediction of the system's behavior.

  11. Testing the quasi-absolute method in photon activation analysis

    SciTech Connect

    Sun, Z. J.; Wells, D.; Starovoitova, V.; Segebade, C.

    2013-04-19

    In photon activation analysis (PAA), relative methods are widely used because of their accuracy and precision. Absolute methods, which are conducted without any assistance from calibration materials, are seldom applied for the difficulty in obtaining photon flux in measurements. This research is an attempt to perform a new absolute approach in PAA - quasi-absolute method - by retrieving photon flux in the sample through Monte Carlo simulation. With simulated photon flux and database of experimental cross sections, it is possible to calculate the concentration of target elements in the sample directly. The QA/QC procedures to solidify the research are discussed in detail. Our results show that the accuracy of the method for certain elements is close to a useful level in practice. Furthermore, the future results from the quasi-absolute method can also serve as a validation technique for experimental data on cross sections. The quasi-absolute method looks promising.

  12. Compressive forces induce osteogenic gene expression in calvarial osteoblasts.

    PubMed

    Rath, Bjoern; Nam, Jin; Knobloch, Thomas J; Lannutti, John J; Agarwal, Sudha

    2008-01-01

    Bone cells and their precursors are sensitive to changes in their biomechanical environment. The importance of mechanical stimuli has been observed in bone homeostasis and osteogenesis, but the mechanisms responsible for osteogenic induction in response to mechanical signals are poorly understood. We hypothesized that compressive forces could exert an osteogenic effect on osteoblasts and act in a dose-dependent manner. To test our hypothesis, electrospun poly(epsilon-caprolactone) (PCL) scaffolds were used as a 3-D microenvironment for osteoblast culture. The scaffolds provided a substrate allowing cell exposure to levels of externally applied compressive force. Pre-osteoblasts adhered, proliferated and differentiated in the scaffolds and showed extensive matrix synthesis by scanning electron microscopy (SEM) and increased Young's modulus (136.45+/-9.15 kPa) compared with acellular scaffolds (24.55+/-8.5 kPa). Exposure of cells to 10% compressive strain (11.81+/-0.42 kPa) resulted in a rapid induction of bone morphogenic protein-2 (BMP-2), runt-related transcription factor 2 (Runx2), and MAD homolog 5 (Smad5). These effects further enhanced the expression of genes and proteins required for extracellular matrix (ECM) production, such as alkaline phosphatase (Akp2), collagen type I (Col1a1), osteocalcin/bone gamma carboxyglutamate protein (OC/Bglap), osteonectin/secreted acidic cysteine-rich glycoprotein (ON/Sparc) and osteopontin/secreted phosphoprotein 1 (OPN/Spp1). Exposure of cell-scaffold constructs to 20% compressive strain (30.96+/-2.82 kPa) demonstrated that these signals are not osteogenic. These findings provide the molecular basis for the experimental and clinical observations that appropriate physical activities or microscale compressive loading can enhance fracture healing due in part to the anabolic osteogenic effects. PMID:18191137

  13. Image compression technique

    DOEpatents

    Fu, Chi-Yung; Petrich, Loren I.

    1997-01-01

    An image is compressed by identifying edge pixels of the image; creating a filled edge array of pixels each of the pixels in the filled edge array which corresponds to an edge pixel having a value equal to the value of a pixel of the image array selected in response to the edge pixel, and each of the pixels in the filled edge array which does not correspond to an edge pixel having a value which is a weighted average of the values of surrounding pixels in the filled edge array which do correspond to edge pixels; and subtracting the filled edge array from the image array to create a difference array. The edge file and the difference array are then separately compressed and transmitted or stored. The original image is later reconstructed by creating a preliminary array in response to the received edge file, and adding the preliminary array to the received difference array. Filling is accomplished by solving Laplace's equation using a multi-grid technique. Contour and difference file coding techniques also are described. The techniques can be used in a method for processing a plurality of images by selecting a respective compression approach for each image, compressing each of the images according to the compression approach selected, and transmitting each of the images as compressed, in correspondence with an indication of the approach selected for the image.

  14. Image compression technique

    DOEpatents

    Fu, C.Y.; Petrich, L.I.

    1997-03-25

    An image is compressed by identifying edge pixels of the image; creating a filled edge array of pixels each of the pixels in the filled edge array which corresponds to an edge pixel having a value equal to the value of a pixel of the image array selected in response to the edge pixel, and each of the pixels in the filled edge array which does not correspond to an edge pixel having a value which is a weighted average of the values of surrounding pixels in the filled edge array which do correspond to edge pixels; and subtracting the filled edge array from the image array to create a difference array. The edge file and the difference array are then separately compressed and transmitted or stored. The original image is later reconstructed by creating a preliminary array in response to the received edge file, and adding the preliminary array to the received difference array. Filling is accomplished by solving Laplace`s equation using a multi-grid technique. Contour and difference file coding techniques also are described. The techniques can be used in a method for processing a plurality of images by selecting a respective compression approach for each image, compressing each of the images according to the compression approach selected, and transmitting each of the images as compressed, in correspondence with an indication of the approach selected for the image. 16 figs.

  15. Intelligent bandwith compression

    NASA Astrophysics Data System (ADS)

    Tseng, D. Y.; Bullock, B. L.; Olin, K. E.; Kandt, R. K.; Olsen, J. D.

    1980-02-01

    The feasibility of a 1000:1 bandwidth compression ratio for image transmission has been demonstrated using image-analysis algorithms and a rule-based controller. Such a high compression ratio was achieved by first analyzing scene content using auto-cueing and feature-extraction algorithms, and then transmitting only the pertinent information consistent with mission requirements. A rule-based controller directs the flow of analysis and performs priority allocations on the extracted scene content. The reconstructed bandwidth-compressed image consists of an edge map of the scene background, with primary and secondary target windows embedded in the edge map. The bandwidth-compressed images are updated at a basic rate of 1 frame per second, with the high-priority target window updated at 7.5 frames per second. The scene-analysis algorithms used in this system together with the adaptive priority controller are described. Results of simulated 1000:1 band width-compressed images are presented. A video tape simulation of the Intelligent Bandwidth Compression system has been produced using a sequence of video input from the data base.

  16. Alternative Compression Garments

    NASA Technical Reports Server (NTRS)

    Stenger, M. B.; Lee, S. M. C.; Ribeiro, L. C.; Brown, A. K.; Westby, C. M.; Platts, S. H.

    2011-01-01

    Orthostatic intolerance after spaceflight is still an issue for astronauts as no in-flight countermeasure has been 100% effective. Future anti-gravity suits (AGS) may be similar to the Shuttle era inflatable AGS or may be a mechanical compression device like the Russian Kentavr. We have evaluated the above garments as well as elastic, gradient compression garments of varying magnitude and determined that breast-high elastic compression garments may be a suitable replacement to the current AGS. This new garment should be more comfortable than the AGS, easy to don and doff, and as effective a countermeasure to orthostatic intolerance. Furthermore, these new compression garments could be worn for several days after space flight as necessary if symptoms persisted. We conducted two studies to evaluate elastic, gradient compression garments. The purpose of these studies was to evaluate the comfort and efficacy of an alternative compression garment (ACG) immediately after actual space flight and 6 degree head-down tilt bed rest as a model of space flight, and to determine if they would impact recovery if worn for up to three days after bed rest.

  17. The unified model, a fully-compressible, non-hydrostatic, deep atmosphere global circulation model, applied to hot Jupiters. ENDGame for a HD 209458b test case

    NASA Astrophysics Data System (ADS)

    Mayne, Nathan J.; Baraffe, Isabelle; Acreman, David M.; Smith, Chris; Browning, Matthew K.; Skålid Amundsen, David; Wood, Nigel; Thuburn, John; Jackson, David R.

    2014-01-01

    We are adapting the global circulation model (GCM) of the UK Met Office, the so-called unified model (UM), for the study of hot Jupiters. In this work we demonstrate the successful adaptation of the most sophisticated dynamical core, the component of the GCM which solves the equations of motion for the atmosphere, available within the UM, ENDGame (Even Newer Dynamics for General atmospheric modelling of the environment). Within the same numerical scheme ENDGame supports solution to the dynamical equations under varying degrees of simplification. We present results from a simple, shallow (in atmospheric domain) hot Jupiter model (SHJ), and a more realistic (with a deeper atmosphere) HD 209458b test case. For both test cases we find that the large-scale, time-averaged (over the 1200 days prescribed test period), dynamical state of the atmosphere is relatively insensitive to the level of simplification of the dynamical equations. However, problems exist when attempting to reproduce the results for these test cases derived from other models. For the SHJ case the lower (and upper) boundary intersects the dominant dynamical features of the atmosphere meaning the results are heavily dependent on the boundary conditions. For the HD 209458b test case, when using the more complete dynamical models, the atmosphere is still clearly evolving after 1200 days, and in a transient state. Solving the complete (deep atmosphere and non-hydrostatic) dynamical equations allows exchange between the vertical and horizontal momentum of the atmosphere, via Coriolis and metric terms. Subsequently, interaction between the upper atmosphere and the deeper more slowly evolving (radiatively inactive) atmosphere significantly alters the results, and acts over timescales longer than 1200 days. Figures 1, 4-8, 10 and 11 are available in electronic form at http://www.aanda.org

  18. Boosting forward-time population genetic simulators through genotype compression

    PubMed Central

    2013-01-01

    Background Forward-time population genetic simulations play a central role in deriving and testing evolutionary hypotheses. Such simulations may be data-intensive, depending on the settings to the various parameters controlling them. In particular, for certain settings, the data footprint may quickly exceed the memory of a single compute node. Results We develop a novel and general method for addressing the memory issue inherent in forward-time simulations by compressing and decompressing, in real-time, active and ancestral genotypes, while carefully accounting for the time overhead. We propose a general graph data structure for compressing the genotype space explored during a simulation run, along with efficient algorithms for constructing and updating compressed genotypes which support both mutation and recombination. We tested the performance of our method in very large-scale simulations. Results show that our method not only scales well, but that it also overcomes memory issues that would cripple existing tools. Conclusions As evolutionary analyses are being increasingly performed on genomes, pathways, and networks, particularly in the era of systems biology, scaling population genetic simulators to handle large-scale simulations is crucial. We believe our method offers a significant step in that direction. Further, the techniques we provide are generic and can be integrated with existing population genetic simulators to boost their performance in terms of memory usage. PMID:23763838

  19. 78 FR 57653 - Agency Information Collection Activities: Comment Request for the Comprehensive Test Ban Treaty...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-09-19

    ... Geological Survey Agency Information Collection Activities: Comment Request for the Comprehensive Test Ban.... Abstract The collection of this information is required by the Comprehensive Test Ban Treaty (CTBT), and...: 1028-0059. Form Number: 9-4040-A. Title: Comprehensive Test Ban Treaty. Type of Request: Extension of...

  20. Fitness Testing in Physical Education--A Misdirected Effort in Promoting Healthy Lifestyles and Physical Activity?

    ERIC Educational Resources Information Center

    Cale, Lorraine; Harris, Jo

    2009-01-01

    Background: Physical fitness testing is commonplace within schools and the physical education (PE) curriculum, with advocates claiming one of the key purposes of testing to be the promotion of healthy lifestyles and physical activity. Despite this, much controversy has surrounded the fitness testing of young people. Purpose: This paper draws on…

  1. 78 FR 7939 - Energy Conservation Program: Test Procedures for Microwave Ovens (Active Mode)

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-02-04

    .... 75 FR 42579, 42581. In addition, in comments received in response to a separate test procedure notice... referred to as the June 2012 NODA). 77 FR 33106. In the June 2012 NODA, DOE presented test results from... single compartment. 78 FR 4015, 4018 (Jan. 18, 2013). For the purpose of this active mode test...

  2. All about compression: A literature review.

    PubMed

    de Carvalho, Magali Rezende; de Andrade, Isabelle Silveira; de Abreu, Alcione Matos; Leite Ribeiro, Andrea Pinto; Peixoto, Bruno Utzeri; de Oliveira, Beatriz Guitton Renaud Baptista

    2016-06-01

    Lower extremity ulcers represent a significant public health problem as they frequently progress to chronicity, significantly impact daily activities and comfort, and represent a huge financial burden to the patient and the health system. The aim of this review was to discuss the best approach for venous leg ulcers (VLUs). Online searches were conducted in Ovid MEDLINE, Ovid EMBASE, EBSCO CINAHL, and reference lists and official guidelines. Keywords considered for this review were VLU, leg ulcer, varicose ulcer, compressive therapy, compression, and stocking. A complete assessment of the patient's overall health should be performed by a trained practitioner, focusing on history of diabetes mellitus, hypertension, dietetic habits, medications, and practice of physical exercises, followed by a thorough assessment of both legs. Compressive therapy is the gold standard treatment for VLUs, and the ankle-brachial index should be measured in all patients before compression application. PMID:27210451

  3. Evaluation of mutagenic activities of endosulfan phosalone, malathion, and permethrin, before and after metabolic activation, in the Ames Salmonella test

    SciTech Connect

    Pednekar, M.D.; Gandhi, S.R.; Netrawali, M.S.

    1987-06-01

    The work reported here evaluates the mutagenic activities of commonly used insecticides - endosulfan (organochlorine), phosalone and malathion (organophosphorus) and permethrin (pyrethroid), before and after activation with cecal microbial extract or with liver post-mitochondrial fraction (S9-fraction) of rat, in Ames test with Salmonella typhimurium tester strains TA 97a, TA 98 and TA 100. As far as we are aware, no study has yet addressed whether the insecticides mentioned above can be mutagenic following their activation by mammalian cecal microorganisms.

  4. The effect of compression on individual pressure vessel nickel/hydrogen components

    NASA Technical Reports Server (NTRS)

    Manzo, Michelle A.; Perez-Davis, Marla E.

    1988-01-01

    Compression tests were performed on representative Individual Pressure Vessel (IPV) Nickel/Hydrogen cell components in an effort to better understand the effects of force on component compression and the interactions of components under compression. It appears that the separator is the most easily compressed of all of the stack components. It will typically partially compress before any of the other components begin to compress. The compression characteristics of the cell components in assembly differed considerably from what would be predicted based on individual compression characteristics. Component interactions played a significant role in the stack response to compression. The results of the compression tests were factored into the design and selection of Belleville washers added to the cell stack to accommodate nickel electrode expansion while keeping the pressure on the stack within a reasonable range of the original preset.

  5. 13C-egg white breath test: a non-invasive test of pancreatic trypsin activity in the small intestine

    PubMed Central

    Evenepoel, P; Hiele, M; Geypens, B; Geboes, K; Rutgeerts, P; Ghoos, Y

    2000-01-01

    BACKGROUND—The recent availability of egg white protein highly enriched with 13C has allowed breath test technology to be adapted for the study of protein digestion and absorption. Pancreatic trypsin is considered to be the key enzyme in the proteolytic cascade.
AIM—To evaluate trypsin activity in the small intestine of healthy volunteers and patients with pancreatic disease by a recently developed 13C-egg white breath test.
METHODS—A total of 48 healthy volunteers and 30 patients with pancreatic disease were studied after ingestion of a test meal consisting of 22 g 13C-labelled egg protein. Breath samples were taken before and after ingestion of the meal and analysed for 13CO2 concentration. Moreover, pancreatic trypsin output after maximal stimulation was measured in 13 patients and nine healthy volunteers.
RESULTS—The six hour cumulative 13CO2 excretion in breath was significantly lower in patients than controls (mean (SEM): 6.23 (0.82)% v 19.16 (0.58)%, p<0.0001). An excellent correlation was found between the six hour cumulative 13CO2 excretion and trypsin activity after maximal pancreatic stimulation.
CONCLUSION—The non-invasive 13C-egg white breath test is promising as an indirect pancreatic proteolytic function test.


Keywords: breath test; pancreatic disease; trypsin; protein; assimilation PMID:10601055

  6. Effect of load introduction on graphite epoxy compression specimens

    NASA Technical Reports Server (NTRS)

    Reiss, R.; Yao, T. M.

    1981-01-01

    Compression testing of modern composite materials is affected by the manner in which the compressive load is introduced. Two such effects are investigated: (1) the constrained edge effect which prevents transverse expansion and is common to all compression testing in which the specimen is gripped in the fixture; and (2) nonuniform gripping which induces bending into the specimen. An analytical model capable of quantifying these foregoing effects was developed which is based upon the principle of minimum complementary energy. For pure compression, the stresses are approximated by Fourier series. For pure bending, the stresses are approximated by Legendre polynomials.

  7. Determination of Plate Compressive Strengths at Elevated Temperatures

    NASA Technical Reports Server (NTRS)

    Heimerl, George J; Roberts, William M

    1950-01-01

    The results of local-instability tests of h-section plate assemblies and compressive stress-strain tests of extruded 75s-t6 aluminum alloy, obtained to determine flat-plate compressive strength under stabilized elevated temperature conditions, are given for temperatures up to 600 degrees F. The results show that methods available for calculating the critical compressive stress at room temperature can also be used at elevated temperatures if the applicable compressive stress-strain curve for the material is given.

  8. An efficient compression scheme for bitmap indices

    SciTech Connect

    Wu, Kesheng; Otoo, Ekow J.; Shoshani, Arie

    2004-04-13

    When using an out-of-core indexing method to answer a query, it is generally assumed that the I/O cost dominates the overall query response time. Because of this, most research on indexing methods concentrate on reducing the sizes of indices. For bitmap indices, compression has been used for this purpose. However, in most cases, operations on these compressed bitmaps, mostly bitwise logical operations such as AND, OR, and NOT, spend more time in CPU than in I/O. To speedup these operations, a number of specialized bitmap compression schemes have been developed; the best known of which is the byte-aligned bitmap code (BBC). They are usually faster in performing logical operations than the general purpose compression schemes, but, the time spent in CPU still dominates the total query response time. To reduce the query response time, we designed a CPU-friendly scheme named the word-aligned hybrid (WAH) code. In this paper, we prove that the sizes of WAH compressed bitmap indices are about two words per row for large range of attributes. This size is smaller than typical sizes of commonly used indices, such as a B-tree. Therefore, WAH compressed indices are not only appropriate for low cardinality attributes but also for high cardinality attributes.In the worst case, the time to operate on compressed bitmaps is proportional to the total size of the bitmaps involved. The total size of the bitmaps required to answer a query on one attribute is proportional to the number of hits. These indicate that WAH compressed bitmap indices are optimal. To verify their effectiveness, we generated bitmap indices for four different datasets and measured the response time of many range queries. Tests confirm that sizes of compressed bitmap indices are indeed smaller than B-tree indices, and query processing with WAH compressed indices is much faster than with BBC compressed indices, projection indices and B-tree indices. In addition, we also verified that the average query response time

  9. Development and Testing of the Observational System for Recording Physical Activity in Children: Elementary School

    ERIC Educational Resources Information Center

    McIver, Kerry L.; Brown, William H.; Pfeiffer, Karin A.; Dowda, Marsha; Pate, Russell R.

    2016-01-01

    Purpose: This study describes the development and pilot testing of the Observational System for Recording Physical Activity-Elementary School (OSRAC-E) Version. Method: This system was developed to observe and document the levels and types of physical activity and physical and social contexts of physical activity in elementary school students…

  10. Activity-Guided Isolation of Bioactive Constituents with Antinociceptive Activity from Muntingia calabura L. Leaves Using the Formalin Test

    PubMed Central

    Mohamad Yusof, Mohd. Izwan; Salleh, Mohd. Zaki; Lay Kek, Teh; Ahmat, Norizan; Nik Azmin, Nik Fatini

    2013-01-01

    The present study was conducted to determine the antinociceptive potential of methanol extract of Muntingia calabura L. (MEMC) and to isolate and identify the bioactive compound(s) responsible for the observed antinociceptive activity. The MEMC and its partitions (petroleum ether (PEP), ethyl acetate (EAP), and aqueous (AQP) partitions), in the dose range of 100, 500, and 1000 mg/kg, were tested using the formalin-induced nociceptive test. The PEP, which exerted the most effective activity in the respective early and late phase, was further subjected to the fractionation procedures and yielded seven fractions (labelled A to G). These fractions were tested, at the dose of 300 mg/kg, together with distilled water or 10% DMSO (negative controls); morphine and aspirin (positive controls) for potential antinociceptive activity. Of all fractions, Fraction D showed the most significant antinociceptive activity, which is considered as equieffective to morphine or aspirin in the early or late phase, respectively. Further isolation and identification processes on fraction D led to the identification of three known and one new compounds, namely, 5-hydroxy-3,7,8-trimethoxyflavone (1), 3,7-dimethoxy-5-hydroyflavone (2), 2′,4′-dihydroxy-3′-methoxychalcone (3), and calaburone (4). At the dose of 50 mg/kg, compound 3 exhibited the highest percentage of antinociceptive activity in both phases of the formalin test. In conclusion, the antinociceptive activity of MEMC involved, partly, the synergistic activation of the flavonoid types of compounds. PMID:24348716

  11. Limiting SUSY compressed spectra scenarios

    NASA Astrophysics Data System (ADS)

    Nelson, Andy; Tanedo, Philip; Whiteson, Daniel

    2016-06-01

    Typical searches for supersymmetry cannot test models in which the two lightest particles have a small ("compressed") mass splitting, due to the small momentum of the particles produced in the decay of the second-to-lightest particle. However, data sets with large missing transverse momentum (ETmiss) can generically search for invisible particle production and therefore provide constraints on such models. We apply data from the ATLAS monojet (jet+ETmiss ) and vector-boson-fusion (forward jets and ETmiss ) searches to such models. In all cases, experimental limits are at least five times weaker than theoretical predictions.

  12. Summary Report on FY12 Small-Scale Test Activities High Temperature Electrolysis Program

    SciTech Connect

    James O'Brien

    2012-09-01

    This report provides a description of the apparatus and the single cell testing results performed at Idaho National Laboratory during January–August 2012. It is an addendum to the Small-Scale Test Report issued in January 2012. The primary program objectives during this time period were associated with design, assembly, and operation of two large experiments: a pressurized test, and a 4 kW test. Consequently, the activities described in this report represent a much smaller effort.

  13. Wavelet compression of medical imagery.

    PubMed

    Reiter, E

    1996-01-01

    Wavelet compression is a transform-based compression technique recently shown to provide diagnostic-quality images at compression ratios as great as 30:1. Based on a recently developed field of applied mathematics, wavelet compression has found success in compression applications from digital fingerprints to seismic data. The underlying strength of the method is attributable in large part to the efficient representation of image data by the wavelet transform. This efficient or sparse representation forms the basis for high-quality image compression by providing subsequent steps of the compression scheme with data likely to result in long runs of zero. These long runs of zero in turn compress very efficiently, allowing wavelet compression to deliver substantially better performance than existing Fourier-based methods. Although the lack of standardization has historically been an impediment to widespread adoption of wavelet compression, this situation may begin to change as the operational benefits of the technology become better known. PMID:10165355

  14. Determination of Importance Evaluation for Exploratory Studies Facility (ESF) Subsurface Testing Activities

    SciTech Connect

    C.J. Byrne

    2001-02-20

    This Determination of Importance Evaluation (DIE) applies to the Subsurface Exploratory Studies Facility (ESF), encompassing the Topopah Spring (TS) Loop from Station 0+00 meters (m) at the North Portal to breakthrough at the South Portal (approximately 78+77 m), and ancillary test and operation support areas including the Enhanced Characterization of the Repository Block (ECRB) Cross Drift. This evaluation applies specifically to site characterization testing activities ongoing and planned in the Subsurface ESF. ESF site characterization activities are being performed to obtain the information necessary to determine whether the Yucca Mountain Site is suitable as a geologic repository for spent nuclear fuel and high-level radioactive waste. A more detailed description of these testing activities is provided in Section 6 of this DIE. Generally, the construction and operation of excavations associated with these testing activities are evaluated in the DIE for the Subsurface ESF (CRWMS M&O 1999a) and the DIE for the ESF ECRB Cross Drift (CRWMS M&O 2000a). The scope of this DIE also entails the proposed Unsaturated Zone (UZ) Transport Test at Busted Butte. Although, not a part of the TS Loop or ECRB Cross Drift, the associated testing activities are Subsurface testing activities. Busted Butte is located to the south south-east of the TS Loop and is outside the Conceptual Controlled Area Boundary (CCAB). These activities provide access to the Calico Hills (CH) geologic structure. In the case of Busted Butte, construction and operation of excavations are evaluated herein (since this activity was not previously evaluated in CRWMS M&O 1999a). The objectives of this DIE are to determine whether Subsurface ESF testing, and associated activities, could potentially impact site characterization testing and/or the waste isolation capabilities of the site. Controls needed to limit any potential impacts are identified in Section 13. The validity and veracity of the individual

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

    NASA Technical Reports Server (NTRS)

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

    2001-01-01

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

  16. Compressive strength of fiber-reinforced composite materials

    NASA Technical Reports Server (NTRS)

    Davis, J. G., Jr.

    1975-01-01

    Results of an experimental and analytical investigation of the compressive strength of unidirectional boron-epoxy composite material are presented. Observation of fiber coordinates in a boron-epoxy composite indicates that the fibers contain initial curvature. Combined axial compression and torsion tests were conducted on boron-epoxy tubes and it was shown that the shear modulus is a function of axial compressive stress. An analytical model which includes initial curvature in the fibers and permits an estimate of the effect of curvature on compressive strength is proposed. Two modes of failure which may result from the application of axial compressive stress are analyzed - delamination and shear instability. Based on tests and analysis, failure of boron-epoxy under axial compressive load is due to shear instability.

  17. Intelligent bandwidth compression

    NASA Astrophysics Data System (ADS)

    Tseng, D. Y.; Bullock, B. L.; Olin, K. E.; Kandt, R. K.; Olsen, J. D.

    1980-02-01

    The feasibility of a 1000:1 bandwidth compression ratio for image transmission has been demonstrated using image-analysis algorithms and a rule-based controller. Such a high compression ratio was achieved by first analyzing scene content using auto-cueing and feature-extraction algorithms, and then transmitting only the pertinent information consistent with mission requirements. A rule-based controller directs the flow of analysis and performs priority allocations on the extracted scene content. The reconstructed bandwidth-compressed image consists of an edge map of the scene background, with primary and secondary target windows embedded in the edge map. The bandwidth-compressed images are updated at a basic rate of 1 frame per second, with the high-priority target window updated at 7.5 frames per second. The scene-analysis algorithms used in this system together with the adaptive priority controller are described. Results of simulated 1000:1 bandwidth-compressed images are presented.

  18. Rate sensitivity and tension–compression asymmetry in AZ31B magnesium alloy sheet

    PubMed Central

    Kurukuri, Srihari; Worswick, Michael J.; Ghaffari Tari, Dariush; Mishra, Raja K.; Carter, Jon T.

    2014-01-01

    The constitutive response of a commercial magnesium alloy rolled sheet (AZ31B-O) is studied based on room temperature tensile and compressive tests at strain rates ranging from 10−3 to 103 s−1. Because of its strong basal texture, this alloy exhibits a significant tension–compression asymmetry (strength differential) that is manifest further in terms of rather different strain rate sensitivity under tensile versus compressive loading. Under tensile loading, this alloy exhibits conventional positive strain rate sensitivity. Under compressive loading, the flow stress is initially rate insensitive until twinning is exhausted after which slip processes are activated, and conventional rate sensitivity is recovered. The material exhibits rather mild in-plane anisotropy in terms of strength, but strong transverse anisotropy (r-value), and a high degree of variation in the measured r-values along the different sheet orientations which is indicative of a higher degree of anisotropy than that observed based solely upon the variation in stresses. This rather complex behaviour is attributed to the strong basal texture, and the different deformation mechanisms being activated as the orientation and sign of applied loading are varied. A new constitutive equation is proposed to model the measured compressive behaviour that captures the rate sensitivity of the sigmoidal stress–strain response. The measured tensile stress–strain response is fit to the Zerilli–Armstrong hcp material model. PMID:24711496

  19. Compression-sensitive magnetic resonance elastography

    NASA Astrophysics Data System (ADS)

    Hirsch, Sebastian; Beyer, Frauke; Guo, Jing; Papazoglou, Sebastian; Tzschaetzsch, Heiko; Braun, Juergen; Sack, Ingolf

    2013-08-01

    Magnetic resonance elastography (MRE) quantifies the shear modulus of biological tissue to detect disease. Complementary to the shear elastic properties of tissue, the compression modulus may be a clinically useful biomarker because it is sensitive to tissue pressure and poromechanical interactions. In this work, we analyze the capability of MRE to measure volumetric strain and the dynamic bulk modulus (P-wave modulus) at a harmonic drive frequency commonly used in shear-wave-based MRE. Gel phantoms with various densities were created by introducing CO2-filled cavities to establish a compressible effective medium. The dependence of the effective medium's bulk modulus on phantom density was investigated via static compression tests, which confirmed theoretical predictions. The P-wave modulus of three compressible phantoms was calculated from volumetric strain measured by 3D wave-field MRE at 50 Hz drive frequency. The results demonstrate the MRE-derived volumetric strain and P-wave modulus to be sensitive to the compression properties of effective media. Since the reconstruction of the P-wave modulus requires third-order derivatives, noise remains critical, and P-wave moduli are systematically underestimated. Focusing on relative changes in the effective bulk modulus of tissue, compression-sensitive MRE may be useful for the noninvasive detection of diseases involving pathological pressure alterations such as hepatic hypertension or hydrocephalus.

  20. Compression-sensitive magnetic resonance elastography.

    PubMed

    Hirsch, Sebastian; Beyer, Frauke; Guo, Jing; Papazoglou, Sebastian; Tzschaetzsch, Heiko; Braun, Juergen; Sack, Ingolf

    2013-08-01

    Magnetic resonance elastography (MRE) quantifies the shear modulus of biological tissue to detect disease. Complementary to the shear elastic properties of tissue, the compression modulus may be a clinically useful biomarker because it is sensitive to tissue pressure and poromechanical interactions. In this work, we analyze the capability of MRE to measure volumetric strain and the dynamic bulk modulus (P-wave modulus) at a harmonic drive frequency commonly used in shear-wave-based MRE. Gel phantoms with various densities were created by introducing CO2-filled cavities to establish a compressible effective medium. The dependence of the effective medium's bulk modulus on phantom density was investigated via static compression tests, which confirmed theoretical predictions. The P-wave modulus of three compressible phantoms was calculated from volumetric strain measured by 3D wave-field MRE at 50 Hz drive frequency. The results demonstrate the MRE-derived volumetric strain and P-wave modulus to be sensitive to the compression properties of effective media. Since the reconstruction of the P-wave modulus requires third-order derivatives, noise remains critical, and P-wave moduli are systematically underestimated. Focusing on relative changes in the effective bulk modulus of tissue, compression-sensitive MRE may be useful for the noninvasive detection of diseases involving pathological pressure alterations such as hepatic hypertension or hydrocephalus. PMID:23852144

  1. Robust retrieval from compressed medical image archives

    NASA Astrophysics Data System (ADS)

    Sidorov, Denis N.; Lerallut, Jean F.; Cocquerez, Jean-Pierre; Azpiroz, Joaquin

    2005-04-01

    Paper addresses the computational aspects of extracting important features directly from compressed images for the purpose of aiding biomedical image retrieval based on content. The proposed method for treatment of compressed medical archives follows the JPEG compression standard and exploits algorithm based on spacial analysis of the image cosine spectrum coefficients amplitude and location. The experiments on modality-specific archive of osteoarticular images show robustness of the method based on measured spectral spatial statistics. The features, which were based on the cosine spectrum coefficients' values, could satisfy different types of queries' modalities (MRI, US, etc), which emphasized texture and edge properties. In particular, it has been shown that there is wealth of information in the AC coefficients of the DCT transform, which can be utilized to support fast content-based image retrieval. The computational cost of proposed signature generation algorithm is low. Influence of conventional and the state-of-the-art compression techniques based on cosine and wavelet integral transforms on the performance of content-based medical image retrieval has been also studied. We found no significant differences in retrieval efficiencies for non-compressed and JPEG2000-compressed images even at the lowest bit rate tested.

  2. Explosive decomposition of hydrazine due to rapid gas compression

    NASA Technical Reports Server (NTRS)

    Briles, O.; Hagemann, D.; Benz, F.; Farkas, T.

    1985-01-01

    Results from tests which attempt to determine conditions which cause explosive decomposition of hydrazine from rapid gas compression are described. Hydrazine was initiated by pressure in combination with shock waves from the pressurant gas. A new test method was developed at the White Sands Test Facility which subjects a gas bubble in contact with liquid hydrazine to pure adiabatic compression. Results from this new test method are compared to those from the U-tube method.

  3. Handbook of microwave testing

    NASA Astrophysics Data System (ADS)

    Laverghetta, T. S.

    A description of microwave test equipment is presented, taking into account signal generators, signal detection/indicating devices, auxiliary testing devices, and microwave systems. Low power, medium power, high power, and peak power measurements are considered along with noise measurements, spectrum analyzer measurements, active testing, antenna measurements, and automatic testing. Attention is given to phase noise, Q measurements, the Time Domain Reflectometry (TDR) measurement, swept impedance, noise sources, noise meters, manual noise measurements, automatic noise figure measurements, gain, gain compression, intermodulation, the third order intercept, and questions of spectral purity.

  4. Determination of Importance Evaluation for Exploratory Studies Facility (ESF) Subsurface Testing Activities

    SciTech Connect

    S. Goodin

    2002-07-22

    This Determination of Importance Evaluation (DIE) applies to the Subsurface Exploratory Studies Facility (ESF), encompassing the Topopah Spring (TS) Loop from Station 0+00 meters (m) at the North Portal to breakthrough at the South Portal (approximately 78+77 m), and ancillary test and operation support areas including the Enhanced Characterization of the Repository Block (ECRB) Cross Drift. This evaluation applies specifically to site characterization testing activities ongoing and planned in the Subsurface ESF. ESF site characterization activities are being performed to obtain the information necessary to determine whether the Yucca Mountain Site is suitable as a geologic repository for spent nuclear fuel and high-level radioactive waste. A more detailed description of these testing activities is provided in Section 6 of this DIE. Generally, the construction and operation of excavations associated with these testing activities are evaluated in the DIE for the Subsurface ESF (CRWMS M&O 1999a) and the DIE for the ESF ECRB Cross Drift (CRWMS M&O 2000a). The scope of this DIE also entails the proposed Unsaturated Zone (UZ) Transport Test at Busted Butte. Although, not a part of the TS Loop or ECRB Cross Drift, the associated testing activities are Subsurface testing activities. Busted Butte is located to the south south-east of the TS Loop and is outside the Conceptual Controlled Area Boundary (CCAB). These activities provide access to the Calico Hills (CH) geologic structure. In the case of Busted Butte, construction and operation of excavations are evaluated herein (since this activity was not previously evaluated in CRWMS M&O 1999a). The objectives of this DIE are to determine whether Subsurface ESF testing, and associated activities, could potentially impact site characterization testing and/or the waste isolation capabilities of the site. Controls needed to limit any potential impacts are identified in Section 13. The validity and veracity of the individual

  5. Compressible Flow Toolbox

    NASA Technical Reports Server (NTRS)

    Melcher, Kevin J.

    2006-01-01

    The Compressible Flow Toolbox is primarily a MATLAB-language implementation of a set of algorithms that solve approximately 280 linear and nonlinear classical equations for compressible flow. The toolbox is useful for analysis of one-dimensional steady flow with either constant entropy, friction, heat transfer, or Mach number greater than 1. The toolbox also contains algorithms for comparing and validating the equation-solving algorithms against solutions previously published in open literature. The classical equations solved by the Compressible Flow Toolbox are as follows: The isentropic-flow equations, The Fanno flow equations (pertaining to flow of an ideal gas in a pipe with friction), The Rayleigh flow equations (pertaining to frictionless flow of an ideal gas, with heat transfer, in a pipe of constant cross section), The normal-shock equations, The oblique-shock equations, and The expansion equations.

  6. Isentropic Compression of Argon

    SciTech Connect

    H. Oona; J.C. Solem; L.R. Veeser, C.A. Ekdahl; P.J. Rodriquez; S.M. Younger; W. Lewis; W.D. Turley

    1997-08-01

    We are studying the transition of argon from an insulator to a conductor by compressing the frozen gas isentropically to pressures at which neighboring atomic orbitals overlap sufficiently to allow some electron motion between atoms. Argon and the other rare gases have closed electron shells and therefore remain montomic, even when they solidify. Their simple structure makes it likely that any measured change in conductivity is due to changes in the atomic structure, not in molecular configuration. As the crystal is compressed the band gap closes, allowing increased conductivity. We have begun research to determine the conductivity at high pressures, and it is our intention to determine the compression at which the crystal becomes a metal.

  7. The compressible mixing layer

    NASA Technical Reports Server (NTRS)

    Vandromme, Dany; Haminh, Hieu

    1991-01-01

    The capability of turbulence modeling correctly to handle natural unsteadiness appearing in compressible turbulent flows is investigated. Physical aspects linked to the unsteadiness problem and the role of various flow parameters are analyzed. It is found that unsteady turbulent flows can be simulated by dividing these motions into an 'organized' part for which equations of motion are solved and a remaining 'incoherent' part represented by a turbulence model. Two-equation turbulence models and second-order turbulence models can yield reasonable results. For specific compressible unsteady turbulent flow, graphic presentations of different quantities may reveal complementary physical features. Strong compression zones are observed in rapid flow parts but shocklets do not yet occur.

  8. Test Activities in the Langley Transonic Dynamics Tunnel and a Summary of Recent Facility Improvements

    NASA Technical Reports Server (NTRS)

    Cole, Stanley R.; Johnson, R. Keith; Piatak, David J.; Florance, Jennifer P.; Rivera, Jose A., Jr.

    2003-01-01

    The Langley Transonic Dynamics Tunnel (TDT) has provided a unique capability for aeroelastic testing for over forty years. The facility has a rich history of significant contributions to the design of many United States commercial transports, military aircraft, launch vehicles, and spacecraft. The facility has many features that contribute to its uniqueness for aeroelasticity testing, perhaps the most important feature being the use of a heavy gas test medium to achieve higher test densities compared to testing in air. Higher test medium densities substantially improve model-building requirements and therefore simplify the fabrication process for building aeroelastically scaled wind tunnel models. This paper describes TDT capabilities that make it particularly suited for aeroelasticity testing. The paper also discusses the nature of recent test activities in the TDT, including summaries of several specific tests. Finally, the paper documents recent facility improvement projects and the continuous statistical quality assessment effort for the TDT.

  9. Antidepressant-like activity of liposomal formulation containing nimodipine treatment in the tail suspension test, forced swim test and MAOB activity in mice.

    PubMed

    Moreno, Lina Clara Gayoso E Almendra Ibiapina; Rolim, Hercília Maria Lins; Freitas, Rivelilson Mendes; Santos-Magalhães, Nereide Stela

    2016-09-01

    Previous studies have shown that intracellular calcium ion dysfunction may be an etiological factor in affective illness. Nimodipine (NMD) is a Ca(2+) channel blocker that has been extensively investigated for therapy of central nervous system (CNS) disorders. In this work, we have evaluated the antidepressant-like activity of nimodipine encapsulated into liposomes (NMD-Lipo) in mice through tail suspension and forced swim assays, as well as MAOB activity. During the tail suspension test, the administration of NMD-Lipo at 0.1, 1 and 10mg/kg was able to promote a reduction in the immobility time of animals greater than the positive control (imipramine). In the forced swim test, the immobility time of mice treated with NMD-Lipo was reduced. This reduction was significantly greater than that found in the animals treated with imipramine and paroxetine. This may suggest that NMD-Lipo provides more antidepressant-like activity than in positive controls. The groups that received a combination of liposomal NMD and antidepressant drugs showed lower immobility time than the groups, which were treated only with imipramine or paroxetine. The mice treated with the combination of NMD-Lipo and reserpine presented an increase in the time of immobility compared with animals treated only with NMD-Lipo. There was a significant decrease in MAOB activity in animals treated with NMD-Lipo compared with untreated animals. The results of the tail suspension test, forced swim test and MAOB activity suggested that the antidepressant activity of NMD-Lipo may be related to an increase in the cerebral monoamine concentrations. PMID:27270234

  10. Monocyte Activation in Immunopathology: Cellular Test for Development of Diagnostics and Therapy

    PubMed Central

    Ivanova, Ekaterina A.; Orekhov, Alexander N.

    2016-01-01

    Several highly prevalent human diseases are associated with immunopathology. Alterations in the immune system are found in such life-threatening disorders as cancer and atherosclerosis. Monocyte activation followed by macrophage polarization is an important step in normal immune response to pathogens and other relevant stimuli. Depending on the nature of the activation signal, macrophages can acquire pro- or anti-inflammatory phenotypes that are characterized by the expression of distinct patterns of secreted cytokines and surface antigens. This process is disturbed in immunopathologies resulting in abnormal monocyte activation and/or bias of macrophage polarization towards one or the other phenotype. Such alterations could be used as important diagnostic markers and also as possible targets for the development of immunomodulating therapy. Recently developed cellular tests are designed to analyze the phenotype and activity of living cells circulating in patient's bloodstream. Monocyte/macrophage activation test is a successful example of cellular test relevant for atherosclerosis and oncopathology. This test demonstrated changes in macrophage activation in subclinical atherosclerosis and breast cancer and could also be used for screening a panel of natural agents with immunomodulatory activity. Further development of cellular tests will allow broadening the scope of their clinical implication. Such tests may become useful tools for drug research and therapy optimization. PMID:26885534

  11. Lossless compression of instrumentation data. Final report

    SciTech Connect

    Stearns, S.D.

    1995-11-01

    This is our final report on Sandia National Laboratories Laboratory- Directed Research and Development (LDRD) project 3517.070. Its purpose has been to investigate lossless compression of digital waveform and image data, particularly the types of instrumentation data generated and processed at Sandia Labs. The three-year project period ran from October 1992 through September 1995. This report begins with a descriptive overview of data compression, with and without loss, followed by a summary of the activities on the Sandia project, including research at several universities and the development of waveform compression software. Persons who participated in the project are also listed. The next part of the report contains a general discussion of the principles of lossless compression. Two basic compression stages, decorrelation and entropy coding, are described and discussed. An example of seismic data compression is included. Finally, there is a bibliography of published research. Taken together, the published papers contain the details of most of the work and accomplishments on the project. This final report is primarily an overview, without the technical details and results found in the publications listed in the bibliography.

  12. [Mutagenic Activity of Four Aminoazo Compounds with Different Carcinogenicity for Rat Liver in the Ames Test].

    PubMed

    Frolova, T S; Sinitsyna, O I; Kaledin, V I

    2015-01-01

    In this paper in the bacterial Ames test we compared the mutagenicity of four aminoazo compounds, previously studied by other researchers and used for activation of rat liver enzymes, with the carcinogenicity in the rat liver. It was found that in the Ames test they have mutagenic activity, however, this activity does not correlate quantitatively with rat sensitivity to their hepatocarcinogenic action. Thus, the most active carcinogen 3'-methyl-4-dimethylaminoazobenzene causes mutations almost 2.5 times less than weakly carcinogenic ortho-aminoazotoluene, and exactly the same number of mutations as non-carcinogenic N,N-diethyl-4-aminoazobenzene. PMID:26591610

  13. Hybrid Electric and Plug-in Hybrid Electric Vehicle Testing Activities

    SciTech Connect

    Donald Karner

    2007-12-01

    The Advanced Vehicle Testing Activity (AVTA) conducts hybrid electric vehicle (HEV) and plug-in hybrid electric vehicle (PHEV) testing in order to provide benchmark data for technology modeling and research and development programs, and to be an independent source of test data for fleet managers and other early adaptors of advanced-technology vehicles. To date, the AVTA has completed baseline performance testing on 12 HEV models and accumulated 2.7 million fleet testing miles on 35 HEVs. The HEV baseline performance testing includes dynamometer and closed-track testing to document HEV performance in a controlled environment. During fleet testing, two of each HEV model accumulate 160,000 test miles within 36 months, during which maintenance and repair events and fuel use were recorded. Three models of PHEVs, from vehicle converters Energy CS and Hymotion and the original equipment manufacturer Renault, are currently in testing. The PHEV baseline performance testing includes 5 days of dynamometer testing with a minimum of 26 test drive cycles, including the Urban Dynamometer Driving Schedule, the Highway Fuel Economy Driving Schedule, and the US06 test cycle, in charge-depleting and charge-sustaining modes. The PHEV accelerated testing is conducted with dedicated drivers for 4,240 miles, over a series of 132 driving loops that range from 10 to 200 miles over various combinations of defined 10-mile urban and 10-mile highway loops, with 984 hours of vehicle charging. The AVTA is part of the U.S. Department of Energy’s FreedomCAR and Vehicle Technologies Program. These AVTA testing activities were conducted by the Idaho National Laboratory and Electric Transportation Applications, with dynamometer testing conducted at Argonne National Laboratory. This paper discusses the testing methods and results.

  14. Systems aspects of COBE science data compression

    NASA Technical Reports Server (NTRS)

    Freedman, I.; Boggess, E.; Seiler, E.

    1993-01-01

    A general approach to compression of diverse data from large scientific projects has been developed and this paper addresses the appropriate system and scientific constraints together with the algorithm development and test strategy. This framework has been implemented for the COsmic Background Explorer spacecraft (COBE) by retrofitting the existing VAS-based data management system with high-performance compression software permitting random access to the data. Algorithms which incorporate scientific knowledge and consume relatively few system resources are preferred over ad hoc methods. COBE exceeded its planned storage by a large and growing factor and the retrieval of data significantly affects the processing, delaying the availability of data for scientific usage and software test. Embedded compression software is planned to make the project tractable by reducing the data storage volume to an acceptable level during normal processing.

  15. FBI compression standard for digitized fingerprint images

    NASA Astrophysics Data System (ADS)

    Brislawn, Christopher M.; Bradley, Jonathan N.; Onyshczak, Remigius J.; Hopper, Thomas

    1996-11-01

    The FBI has formulated national standards for digitization and compression of gray-scale fingerprint images. The compression algorithm for the digitized images is based on adaptive uniform scalar quantization of a discrete wavelet transform subband decomposition, a technique referred to as the wavelet/scalar quantization method. The algorithm produces archival-quality images at compression ratios of around 15 to 1 and will allow the current database of paper fingerprint cards to be replaced by digital imagery. A compliance testing program is also being implemented to ensure high standards of image quality and interchangeability of data between different implementations. We will review the current status of the FBI standard, including the compliance testing process and the details of the first-generation encoder.

  16. Isentropic compression of argon

    SciTech Connect

    Veeser, L.R.; Ekdahl, C.A.; Oona, H.

    1997-06-01

    The compression was done in an MC-1 flux compression (explosive) generator, in order to study the transition from an insulator to a conductor. Since conductivity signals were observed in all the experiments (except when the probe is removed), both the Teflon and the argon are becoming conductive. The conductivity could not be determined (Teflon insulation properties unknown), but it could be bounded as being {sigma}=1/{rho}{le}8({Omega}cm){sub -1}, because when the Teflon breaks down, the dielectric constant is reduced. The Teflon insulator problem remains, and other ways to better insulate the probe or to measure the conductivity without a probe is being sought.

  17. Genotoxic activity detected in soils from a hazardous waste site by the Ames test and an SOS colorimetric test

    SciTech Connect

    McDaniels, A.E.; Reyes, A.L.; Wymer, L.J.; Rankin, C.C.; Stelma, G.N. Jr. )

    1993-01-01

    Ten soil samples from a hazardous waste site were compared for their genotoxic activity by the Ames test (Salmonella reverse mutation assay) and a modified SOS colorimetric test. Polynuclear aromatic hydrocarbons known to produce frameshift mutations were found in high levels in the soils. Salmonella typhimurium TA98, sensitive to frameshift mutations, was selected as the Ames tester strain. Escherichia coli K12 PQ37 (sulA::lacZ) was the SOS tester strain. Organic extracts were prepared from the soil samples by Soxhlet extraction. One set of the soil samples was extracted with methylene chloride and a second set with cyclohexane. Two criteria from reproducible dose-related increases in response to the soil were used to compare the positive responses: 1. the concentrations required for doubling responses and 2. a minimum concentration required to produce statistically significant increases from background controls. Analysis of variance indicated that with S9 mix, Ames and SOS results were similar for the same soils and solvent extractions. However, without S9 mix, the SOS test was significantly more sensitive than the Ames test to the genotoxins extracted from the soils. Both the Ames and SOS tests detected lower concentrations of genotoxins in methylene chloride than in cyclohexane extracts. The simplicity of the method, reduction in expenses, and results within 1 working day all contribute to the advantages of the SOS test.

  18. Auditory Discrimination Using Frequency-Modulated Amplification with Long-Term Amplitude Compression.

    NASA Astrophysics Data System (ADS)

    Shea, Bernard David

    This dissertation considers the effects of long -term amplitude compression used in narrow-band frequency modulated (FM) assistive listening devices on the auditory discrimination of severely and profoundly hearing-impaired individuals. Compression has been used in narrow-band FM transmitters for hearing-impaired children in educational programs for over twenty years. It restricts the peak deviation of the FM signal to within allowable limits. Narrow -band FM equipment can vary in peak limitation approaches via compression, i.e., using a form of compression limiting or using long-term compression (automatic volume control). Numerous investigations have studied the benefits of FM system use, but none have tested the benefits or deleterious effects of these compression forms on the auditory discrimination of hearing-impaired individuals. Despite the marked limitations associated with severe or profound sensorineural hearing impairment in children, spoken language development is possible. Research and experience have suggested that the auditory system represents the best sensory input channel for these children. With appropriate amplification and educational intervention they can achieve dramatic improvements in speech perception, speech production, language development, and educational achievement (Boothroyd, 1985; Hudgins, 1953, 1954; Ling & Milne, 1981; Wedenberg, 1954). Most hearing-impaired children in educational programs across the United States receive the amplified teacher's speech signal via narrow-band frequency modulated (FM) transmission, yet a controlled investigation of the input compression used in these systems has never been conducted. This dissertation reviews and discusses narrow -band frequency modulated (FM) radio wave systems and the use of audio compression. The experiment tested 32 students with severe to profound sensorineural hearing loss under two narrow -band FM transmitter conditions. The FM transmitter conditions were varied on the basis

  19. Inhibition of Hyperpolarization-Activated Cation Current in Medium-Sized DRG Neurons Contributed to the Antiallodynic Effect of Methylcobalamin in the Rat of a Chronic Compression of the DRG

    PubMed Central

    Zhang, Ming; Han, Wenjuan; Zheng, Jianyong; Meng, Fancheng; Jiao, Xiying; Hu, Sanjue; Xu, Hui

    2015-01-01

    Recently several lines of evidence demonstrated that methylcobalamin (MeCbl) might have potential analgesic effect in experimental and clinical studies. However, it was reported that MeCbl had no effect on treating lumbar spinal stenosis induced pain. Thus, the effects of short-term and long-term administration of MeCbl were examined in the chronic compression of dorsal root ganglion (CCD) model. We found that mechanical allodynia was significantly inhibited by a continuous application of high dose and a single treatment of a super high dose of MeCbl. Little is known about mechanisms underlying the analgesia of MeCbl. We examined the effect of MeCbl on the spontaneous activity (SA), the excitability, and hyperpolarization-activated nonselective cation ion current in compressed medium-sized dorsal root ganglion (DRG) neurons using extracellular single fiber recording in vivo and whole-cell patch clamp in vitro. We found that MeCbl significantly inhibited the SA of A-type sensory neurons in a dose-dependent manner and inhibited the excitability of medium-sized DRG neurons. In addition, MeCbl also decreased Ih current density in injured medium-sized DRG neurons. Our results proved that MeCbl might exert an analgesic effect through the inhibition Ih current and then might inhibit the hyperexcitability of primary sensory neurons under neuropathic pain state. PMID:26101670

  20. Development and testing of heat transport fluids for use in active solar heating and cooling systems

    NASA Technical Reports Server (NTRS)

    Parker, J. C.

    1981-01-01

    Work on heat transport fluids for use with active solar heating and cooling systems is described. Program objectives and how they were accomplished including problems encountered during testing are discussed.