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1

High resolution color band pyrometer ratioing  

NASA Technical Reports Server (NTRS)

The sensing head of a two-color band ratioing pyrometer of a known type using a fiber optic cable to couple radiation to dual detector photodiodes is improved to have high spatial resolution by focusing the radiation received through an objective lens (i.e., by focusing the image of a target area) onto an opaque sheet spaced in front of the input end of the fiber optic cable. A two-mil hole in that sheet then passes radiation to the input end of the cable. The detector has two channels, one for each color band, with an electronic-chopper stabilized current amplifier as the input stage followed by an electronic-chopper stabilized voltage amplifier.

Bickler, Donald B. (Inventor); Henry, Paul K. (Inventor); LoGiurato, D. Daniel (Inventor)

1989-01-01

2

PYROLASER - PYROLASER OPTICAL PYROMETER OPERATING SYSTEM  

NASA Technical Reports Server (NTRS)

The PYROLASER package is an operating system for the Pyrometer Instrument Company's Pyrolaser. There are 6 individual programs in the PYROLASER package: two main programs, two lower level subprograms, and two programs which, although independent, function predominantly as macros. The package provides a quick and easy way to setup, control, and program a standard Pyrolaser. Temperature and emissivity measurements may be either collected as if the Pyrolaser were in the manual operations mode, or displayed on real time strip charts and stored in standard spreadsheet format for post-test analysis. A shell is supplied to allow macros, which are test-specific, to be easily added to the system. The Pyrolaser Simple Operation program provides full on-screen remote operation capabilities, thus allowing the user to operate the Pyrolaser from the computer just as it would be operated manually. The Pyrolaser Simple Operation program also allows the use of "quick starts". Quick starts provide an easy way to permit routines to be used as setup macros for specific applications or tests. The specific procedures required for a test may be ordered in a sequence structure and then the sequence structure can be started with a simple button in the cluster structure provided. One quick start macro is provided for continuous Pyrolaser operation. A subprogram, Display Continuous Pyr Data, is used to display and store the resulting data output. Using this macro, the system is set up for continuous operation and the subprogram is called to display the data in real time on strip charts. The data is simultaneously stored in a spreadsheet format. The resulting spreadsheet file can be opened in any one of a number of commercially available spreadsheet programs. The Read Continuous Pyrometer program is provided as a continuously run subprogram for incorporation of the Pyrolaser software into a process control or feedback control scheme in a multi-component system. The program requires the Pyrolaser to be set up using the Pyrometer String Transfer macro. It requires no inputs and provides temperature and emissivity as outputs. The Read Continuous Pyrometer program can be run continuously and the data can be sampled as often or as seldom as updates of temperature and emissivity are required. PYROLASER is written using the Labview software for use on Macintosh series computers running System 6.0.3 or later, Sun Sparc series computers running OpenWindows 3.0 or MIT's X Window System (X11R4 or X11R5), and IBM PC or compatibles running Microsoft Windows 3.1 or later. Labview requires a minimum of 5Mb of RAM on a Macintosh, 24Mb of RAM on a Sun, and 8Mb of RAM on an IBM PC or compatible. The Labview software is a product of National Instruments (Austin,TX; 800-433-3488), and is not included with this program. The standard distribution medium for PYROLASER is a 3.5 inch 800K Macintosh format diskette. It is also available on a 3.5 inch 720K MS-DOS format diskette, a 3.5 inch diskette in UNIX tar format, and a .25 inch streaming magnetic tape cartridge in UNIX tar format. An electronic copy of the documentation in Macintosh WordPerfect version 2.0.4 format is included on the distribution medium. Printed documentation is included in the price of the program. PYROLASER was developed in 1992.

Roberts, F. E.

1994-01-01

3

Optical pyrometer system for collisionless shock experiments in high-power laser-produced plasmasa)  

NASA Astrophysics Data System (ADS)

A temporally and spatially resolved optical pyrometer system has been fielded on Gekko XII experiments. The system is based on the self-emission measurements with a gated optical imager (GOI) and a streaked optical pyrometer (SOP). Both detectors measure the intensity of the self-emission from laser-produced plasmas at the wavelength of 450 nm with a bandpass filter with a width of ˜10 nm in FWHM. The measurements were calibrated with different methods, and both results agreed with each other within 30% as previously reported [T. Morita et al., Astrophys. Space Sci. 336, 283 (2011)], 10.1007/s10509-010-0525-5. As a tool for measuring the properties of low-density plasmas, the system is applicable for the measurements of the electron temperature and density in collisionless shock experiments [Y. Kuramitsu et al., Phys. Rev. Lett. 106, 175002 (2011)], 10.1103/PhysRevLett.106.175002.

Morita, T.; Sakawa, Y.; Kuramitsu, Y.; Dono, S.; Ide, T.; Shibata, S.; Aoki, H.; Tanji, H.; Sano, T.; Shiroshita, A.; Waugh, J. N.; Gregory, C. D.; Woolsey, N. C.; Takabe, H.

2012-10-01

4

Study of the Performance of a Streaked Optical Pyrometer System for Temperature Measurement of Shocked Materials  

NASA Astrophysics Data System (ADS)

A streaked optical pyrometer (SOP) is developed and calibrated for the measurement of the temperature of shocked materials. In order to achieve a higher relative sensitivity, a one-channel scheme is adopted for the system. The system is calibrated with a shocked step-shaped aluminum sample in the SG-III prototype laser facility. The relation between the count number in the detection system and the sample temperature is thus obtained, which can be adopted to infer the temperature of any shocked materials in future experiments.

Zhang, Chen; Liu, Hao; Wang, Zhebin; Jiang, Xiaohua; Zhang, Huige; Liu, Yonggang; Li, Zhichao; Li, Sanwei; Yang, Dong; Ding, Yongkun; Zhao, Bin; Hu, Guangyue; Zheng, Jian

2014-06-01

5

Streaked Optical Pyrometer System for Laser-Driven Shock-Wave Experiments on OMEGA  

SciTech Connect

The temperature of laser-driven shock waves is of interest to inertial confinement fusion and high-energy-density physics. We report on a streaked optical pyrometer that measures the self-emission of laser-driven shocks simultaneously with a velocity interferometer system for any reflector (VISAR). Together these diagnostics are used to obtain the temporally and spatially resolved temperatures of ~Mbar shocks driven by the OMEGA laser. We provide a brief description of the diagnostic and how it is used with VISAR. Key spectral calibration results are discussed and important characteristics of the recording system are presented.

Miller, J.E.; Boehly, T.R.; Melchior, Meyerhofer, D.D.; Celliers, P.M.; Eggert, J.H.; Hicks, D.G.; Sorce, C.M.; Oertel, J.A.; Emmel, P.M.

2007-03-23

6

Improvements to the three-color optical CCD-based pyrometer system  

SciTech Connect

We put forward an improved three-color measurement scheme with a color CCD sensor using the combination of effective wavelengths and blackbody calibrations. The process of effective wavelengths realizes the separation of the emissivity function from the measurement integral equation. This improved method not only effectively avoids errors arising from the traditional process adopting the basic wavelengths, but also simplifies the complex integral calculations. For a blackbody or graybody, the measurement performance of the pyrometer was experimentally investigated from the point of the temperature sensitivity. The results show that narrowing the spectrum bandwidth with different bandpass spectral filters may improve the temperature sensitivities. The spectrum adjustment not only makes the linear emissivity more suitable in the narrower waveband, but also reduces the numerical uncertainty of the effective wavelengths. For nongray objects, the effects of the numerical uncertainty of the effective wavelengths to measurements were quantificationally evaluated at different measurement conditions (different temperatures, emissivities, and spectrums). The results indicate that the reference values of 584, 555, and 511nm or 607, 560, and 506nm of the effective wavelengths are reasonable for the present system with the modified spectral response using Filter 1 or Filter 2. The maximum calculation errors arising from the reference effective wavelengths are less than 1.6%. In this paper, the technical realization steps of the improved method are also described. The measurement experiments of a metal sample in hot environments were carried out to further verify the applicability of this improved CCD-based pyrometer. The results agreed well with the spectrometer-based results.

Fu Tairan; Zhao Huan; Zeng Jun; Wang Zhe; Zhong Maohua; Shi Congling

2010-11-01

7

The use of optical pyrometers in axial flow turbines  

SciTech Connect

An optical pyrometer system that can be used to measure metal temperatures over an extended range of temperature has been developed. Real-time flame discrimination permits accurate operation in the gas turbine environment with high flame content. This versatile capability has been used in a number of ways. In experimental engines, a fixed angle pyrometer has been used for turbine health monitoring for the automatic test stand abort system. Turbine blade creep capability has been improved by tailoring the burner profile based on measured blade temperatures. Fixed and traversing pyrometers were used extensively during engine development to map blade surface temperatures in order to assess cooling effectiveness and identify optimum configurations. Portable units have been used in turbine field inspections. A new low temperature pyrometer is being used as a diagnostic tool in the alternate turbopump design for the Space Shuttle main engine. Advanced engine designs will incorporate pyrometers in the engine control system to limit operation to safe temperatures.

Sellers, R.R.; Przirembel, H.R.; Clevenger, D.H.; Lang, J.L.

1989-01-01

8

Active millimeter-wave pyrometer  

SciTech Connect

There is a continuing need for reliable and accurate temperature measurements inside hot and dirty environments. Many processes encompassing manufacturing, waste remediation, and power production make use of high temperature furnaces where currently available temperature measurement instrumentation is not always adequate. Thermocouples require direct surface contact and are limited to temperatures < 1700{degrees}C. Infrared pyrometers require clear, direct lines of sight that are frequently unavailable or become obscured during operations. Furthermore the surface emissivity, which can vary during the process, must be known. Millimeter-wave pyrometry overcomes all these limitations. A 135 GHz heterodyne receiver with a rotatable graphite waveguide/mirror system has been implemented on a waste remediation DC arc furnace for internal surface temperature measurements. The linear temperature measurement range extends from <1{degrees} to approximately 15,000{degrees}C relative to ambient with a simultaneous capability to monitor surface reflectivity with the local oscillator leakage. Reliable and robust operation on a continuous 24 hour basis in a smoky, dirty furnace environment is demonstrated for more than 5 furnace runs reaching a maximum temperature of 2200{degrees}C. Complete temperature profile measurements with approximately 5 cm spatial resolution clearly documented thermal gradients on the slag melt surface and refractory walls and ceiling for all operating regimes of the furnace. The unique active probing capability of this instrument provided additional real time information on melt surface turbulence, changing furnace wall emissivity, and millimeter-wave optic losses inside the furnace.

Woskov, P.P. [Massachusettes Institute of Technology, Cambridge, MA (United States)

1995-04-01

9

Scanning optical pyrometer for measuring temperatures in hollow cathodes  

SciTech Connect

Life-limiting processes in hollow cathodes are determined largely by the temperature of the electron emitter. To support cathode life assessment, a noncontact temperature measurement technique which employs a stepper motor-driven fiber optic probe was developed. The probe is driven inside the hollow cathode and collects light radiated by the hot interior surface of the emitter. Ratio pyrometry is used to determine the axial temperature profile. Thermocouples on the orifice plate provide measurements of the external temperature during cathode operation and are used to calibrate the pyrometer system in situ with a small oven enclosing the externally heated cathode. The diagnostic method and initial measurements of the temperature distribution in a hollow cathode are discussed.

Polk, J. E.; Marrese-Reading, C. M.; Thornber, B.; Dang, L.; Johnson, L. K.; Katz, I. [Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California 91109 (United States); International Space University, 67000 Strasbourg (France); California Institute of Technology, Pasadena, California 91109 (United States); Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California 91109 (United States)

2007-09-15

10

A Self Calibrating Emissivity and/or Transmissivity Independent Multiwavelength Pyrometer  

NASA Technical Reports Server (NTRS)

Pyrometer is a favorite method to do remote temperature measurement in research and development. One-color, two-color and the disappearing filament pyrometers are most common, multicolor and multiwavelength pyrometers are being introduced recently. All these pyrometers invariably require, in one form or another, information concerning emissivity, the medium transmissivity, their ratio at some two spectral regions, the instrument's calibration constant, etc. for their operation. This information can come from hand books, from the manufacturer or in some instances, from results of dedicated separate experiments. Often this information is sample or instrument specific. Sometimes this information, though obtained from a special experiment, is obtained using a separate sample rather than the one pursued for temperature measurement. Then, there would be the question of variability from sample to sample and variability from batch to batch in the sample used. Also, previously determined calibrations can change with time, and the only way to reduce uncertainty is to perform the calibration more frequently or even immediately before the experiment. We have developed a multiwavelength pyrometer, which eliminates the need to supply the necessary emissivity and/or transmissivity information and the instrument calibration constants ahead of time. The pyrometer calibrates itself from its first cycle data.

Ng, Daniel

1996-01-01

11

Self-calibrated active pyrometer for furnace temperature measurements  

DOEpatents

Pyrometer with a probe beam superimposed on its field-of-view for furnace temperature measurements. The pyrometer includes a heterodyne millimeter/sub-millimeter-wave or microwave receiver including a millimeter/sub-millimeter-wave or microwave source for probing. The receiver is adapted to receive radiation from a surface whose temperature is to be measured. The radiation includes a surface emission portion and a surface reflection portion which includes the probe beam energy reflected from the surface. The surface emission portion is related to the surface temperature and the surface reflection portion is related to the emissivity of the surface. The simultaneous measurement of surface emissivity serves as a real time calibration of the temperature measurement. In an alternative embodiment, a translatable base plate and a visible laser beam allow slow mapping out of interference patterns and obtaining peak values therefor. The invention also includes a waveguide having a replaceable end portion, an insulating refractory sleeve and/or a source of inert gas flow. The pyrometer may be used in conjunction with a waveguide to form a system for temperature measurements in a furnace. The system may employ a chopper or alternatively, be constructed without a chopper. The system may also include an auxiliary reflector for surface emissivity measurements.

Woskov, Paul P. (Bedford, MA); Cohn, Daniel R. (Chestnuthill, MA); Titus, Charles H. (Newtown Square, PA); Surma, Jeffrey E. (Kennewick, WA)

1998-01-01

12

High-Resolution, Two-Wavelength Pyrometer  

NASA Technical Reports Server (NTRS)

Modified two-color pyrometer measures temperatures of objects with high spatial resolution. Image focused on hole 0.002 in. (0.05 mm) in diameter in brass sheet near end of bundle, causing image to be distributed so fibers covered by defocused radiation from target. Pinhole ensures radiation from only small part of target scene reaches detector, thus providing required spatial resolution. By spreading radiation over bundle, pinhole ensures entire active area of detectors utilized. Produces signal as quiet as conventional instruments but with only 1/64 input radiation.

Bickler, Donald B.; Henry, Paul K.; Logiurato, D. Daniel

1989-01-01

13

Active millimeter-wave pyrometer  

SciTech Connect

A 135 GHz heterodyne receiver with a rotatable graphite waveguide/mirror system has been implemented on a waste remediation direct-current arc furnace for internal surface temperature measurements. The linear temperature measurement range extends from {lt}1{degree} to approximately 15,000 {degree}C relative to ambient with a simultaneous capability to monitor surface reflectivity with the local oscillator leakage. Reliable and robust operation on a continuous 24 h basis in a smoky, dirty furnace environment is demonstrated for a total of five furnace runs reaching a maximum temperature of 2200 {degree}C. Complete temperature profile measurements with approximately 5 cm spatial resolution clearly documented thermal gradients on the slag melt surface and refractory walls and ceiling for all operating regimes of the furnace. The unique active probing capability of this instrument provided additional real-time information on melt surface turbulence, changing furnace wall emissivity, and millimeter-wave optic losses inside the furnace. {copyright} {ital 1995} {ital American} {ital Institute} {ital of} {ital Physics}.

Woskov, P.P.; Cohn, D.R.; Rhee, D.Y.; Thomas, P. [Plasma Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States)] [Plasma Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States); Titus, C.H. [T& R Associates, Wayne, Pennsylvania 19087 (United States)] [T& R Associates, Wayne, Pennsylvania 19087 (United States); Surma, J.E. [Pacific Northwest Laboratories, Richland, Washington 99352 (United States)] [Pacific Northwest Laboratories, Richland, Washington 99352 (United States)

1995-08-01

14

Development of three-wavelength CCD image pyrometer used for the temperature field measurements of continuous casting billets  

NASA Astrophysics Data System (ADS)

This paper develops an imaging based three-color pyrometer for the monitoring of temperature distribution in a continuous casting billet. A novel optical device, together with an embedded electronic system, is designed to sequentially collect a dark image and three thermal images with specified wavelengths on a same monochromatic charge-coupled-device (CCD). The three thermal images provide the basis for the determination of target temperature, while the dark image is used to online eliminate the dark noise of CCD with a differential method. This image pyrometer is not only independent of target emissivity but also overcomes the dissimilarity of measuring accuracy between the micro-sensors of CCD resulted from the non-uniformity of pixels' intensity response and the vignetting of optical system. Furthermore, a precise two-color temperature field measuring model on the CCD pyrometer is established, based on which a self-adaptive light-integration mechanism is presented. Compared with the traditional fixed light-integration method, the measuring range of the pyrometer is greatly extended and its sensitivity in low temperature segment is improved. The test results in a steel factory demonstrate that the pyrometer is capable of meeting the requirement of surface temperature measurements about casting billets. Reliability and accuracy of measurement results are also discussed herein.

Xie, Zhi; Bai, Haicheng

2014-02-01

15

Development of three-wavelength CCD image pyrometer used for the temperature field measurements of continuous casting billets.  

PubMed

This paper develops an imaging based three-color pyrometer for the monitoring of temperature distribution in a continuous casting billet. A novel optical device, together with an embedded electronic system, is designed to sequentially collect a dark image and three thermal images with specified wavelengths on a same monochromatic charge-coupled-device (CCD). The three thermal images provide the basis for the determination of target temperature, while the dark image is used to online eliminate the dark noise of CCD with a differential method. This image pyrometer is not only independent of target emissivity but also overcomes the dissimilarity of measuring accuracy between the micro-sensors of CCD resulted from the non-uniformity of pixels' intensity response and the vignetting of optical system. Furthermore, a precise two-color temperature field measuring model on the CCD pyrometer is established, based on which a self-adaptive light-integration mechanism is presented. Compared with the traditional fixed light-integration method, the measuring range of the pyrometer is greatly extended and its sensitivity in low temperature segment is improved. The test results in a steel factory demonstrate that the pyrometer is capable of meeting the requirement of surface temperature measurements about casting billets. Reliability and accuracy of measurement results are also discussed herein. PMID:24593387

Xie, Zhi; Bai, Haicheng

2014-02-01

16

Development of three-wavelength CCD image pyrometer used for the temperature field measurements of continuous casting billets  

SciTech Connect

This paper develops an imaging based three-color pyrometer for the monitoring of temperature distribution in a continuous casting billet. A novel optical device, together with an embedded electronic system, is designed to sequentially collect a dark image and three thermal images with specified wavelengths on a same monochromatic charge-coupled-device (CCD). The three thermal images provide the basis for the determination of target temperature, while the dark image is used to online eliminate the dark noise of CCD with a differential method. This image pyrometer is not only independent of target emissivity but also overcomes the dissimilarity of measuring accuracy between the micro-sensors of CCD resulted from the non-uniformity of pixels’ intensity response and the vignetting of optical system. Furthermore, a precise two-color temperature field measuring model on the CCD pyrometer is established, based on which a self-adaptive light-integration mechanism is presented. Compared with the traditional fixed light-integration method, the measuring range of the pyrometer is greatly extended and its sensitivity in low temperature segment is improved. The test results in a steel factory demonstrate that the pyrometer is capable of meeting the requirement of surface temperature measurements about casting billets. Reliability and accuracy of measurement results are also discussed herein.

Xie, Zhi; Bai, Haicheng [State Key Laboratory of Synthetical Automation for Process Industries, School of Information Science and Engineering, Northeastern University, Shenyang 110819 (China)] [State Key Laboratory of Synthetical Automation for Process Industries, School of Information Science and Engineering, Northeastern University, Shenyang 110819 (China)

2014-02-15

17

Multispectral precise pyrometer for measurement of seawater surface temperature  

NASA Astrophysics Data System (ADS)

The paper presents selected problems referring to remote precise temperature measurements. A method of correction of temperature measurement of seawater, disturbed by sun radiation, and a method of elimination of power supply interference were discussed for multispectral IR pyrometer.

Madura, H.; Piatkowski, T.; Powiada, E.

2004-12-01

18

A fast UV/visible pyrometer for shock temperature measurements to 20 000 K  

SciTech Connect

An ultraviolet/visible pyrometer is described which can measure shock temperatures from 3000 to 20 000 K. The system is modular, and in general consists of six photomultiplier tubes and two linear intensified diode array/spectrograph systems which can cover the range from 250 to 800 nm. Extension of the pyrometer's capabilities into the ultraviolet is necessary for accurate measurements above 8000 K. The nature of the shock environment requires the photomultiplier tubes to have rise times on the order of 2 ns, with a typical experiment lasting between 20 and 500 ns. The system measures absolute intensity, and is calibrated against a known tungsten lamp prior to each experiment. The highest temperature measured was 18 300 K for fluid Xe. The targets needed to contain this type of cryogenic sample are described as well.

Radousky, H.B.; Mitchell, A.C. (Lawrence Livermore National Laboratory, Livermore, California 94550 (US))

1989-12-01

19

Temperature Measurement of Ceramic Materials Using a Multiwavelength Pyrometer  

NASA Technical Reports Server (NTRS)

The surface temperatures of several pure ceramic materials (alumina, beryllia, magnesia, yittria and spinel) in the shape of pellets were measured using a multiwavelength pyrometer. In one of the measurements, radiation signal collection is provided simply by an optical fiber. In the other experiments, a 4.75 inch (12 cm) parabolic mirror collects the signal for the spectrometer. Temperature measurement using the traditional one- and two-color pyrometer for these ceramic materials is difficult because of their complex optical properties, such as low emissivity which varies with both temperature and wavelength. In at least one of the materials, yittria, the detected optical emission increased as the temperature was decreased due to such emissivity variation. The reasons for such changes are not known. The multiwavelength pyrometer has demonstrated its ability to measure surface temperatures under such conditions. Platinum electrodes were embedded in the ceramic pellets for resistance measurements as the temperature changed.

Ng, Daniel; Fralick, Gustave

1999-01-01

20

A high-speed four-channel infrared pyrometer  

SciTech Connect

A high-speed, four-wavelength pyrometer has been developed for dynamic temperature measurements on samples that are heated by shock compression. The pyrometer uses a pair of off-axis parabolic mirrors to collect radiance emitted from a target of 1 mm in diameter. A single optical fiber delivers the collected radiant flux to the detector housing. Three dichroic beam splitters are used to spectrally split the light into four beams that are then focused onto an equal number of LN2-cooled InSb photodetectors. Broad bandwidth interference filters that are nominally centered at 1.8, 2.4, 3.4, and 5.0 {micro}m define the wavelength ranges of the four channels. The blackbody-temperature threshold of the pyrometer is at about 400 K. The signals are recorded at intervals as short as 20 ns using a four-channel digital oscilloscope. Procedures for calibration and temperature measurements are described.

Boboridis, K.; Obst, A. W. (Andrew W.)

2002-01-01

21

Temperature measurement in WTE boilers using suction pyrometers.  

PubMed

The temperature of the flue-gas in the post combustion zone of a waste to energy (WTE) plant has to be maintained within a fairly narrow range of values, the minimum of which is prescribed by the European Waste Directive 2000/76/CE, whereas the maximum value must be such as to ensure the preservation of the materials and the energy efficiency of the plant. A high degree of accuracy in measuring and controlling the aforementioned temperature is therefore required. In almost the totality of WTE plants this measurement process is carried out by using practical industrial thermometers, such as bare thermocouples and infrared radiation (IR) pyrometers, even if affected by different physical contributions which can make the gas temperature measurements incorrect. The objective of this paper is to analyze errors and uncertainties that can arise when using a bare thermocouple or an IR pyrometer in a WTE plant and to provide a method for the in situ calibration of these industrial sensors through the use of suction pyrometers. The paper describes principle of operation, design, and uncertainty contributions of suction pyrometers, it also provides the best estimation of the flue-gas temperature in the post combustion zone of a WTE plant and the estimation of its expanded uncertainty. PMID:24248279

Rinaldi, Fabio; Najafi, Behzad

2013-01-01

22

Application of the Self Calibrating Emissivity and/or Transmissivity Independent Multiwavelength Pyrometer in an Intense Ambient Radiation Environment  

NASA Technical Reports Server (NTRS)

The NASA self calibrating multiwavelength pyrometer is a recent addition to the list of pyrometers used in remote temperature measurement in research and development. The older one-color, two-color, and the disappearing filament pyrometers, as well as the multicolor and early multiwavelength pyrometers, all do not operate successfully in situations in which strong ambient radiation coexists with radiation originating from the measured surface. In such situations radiation departing from the target surface arrives at the pyrometer together with radiation coming from another source either directly or through reflection. Unlike the other pyrometers, the self calibrating multiwavelength pyrometer can still calibrate itself and measure the temperatures in this adverse environment.

Ng, Daniel

1996-01-01

23

Radiation temperature measurement method for semitransparent materials using one-channel infrared pyrometer.  

PubMed

Semitransparent zinc sulfide (ZnS) crystal materials are widely used as the infrared-transmitting windows for optical instruments operating in long wavelengths. This paper describes a temperature measurement method for high-temperature ZnS materials using the one-channel optical pyrometer based on a theoretical model of radiation transfer in semitransparent plates. Numerical analyses of the radiation properties of ZnS plate are used to optimize the spectral band for the optical pyrometry. The optimized measurement spectral band is based on a trade-off between the measurement radiation intensity and the signal-to-noise ratio (SNR) for the ZnS material. The effective waveband emittance of one-dimensional (1D) ZnS plates is analyzed for various experimental conditions (temperatures, thicknesses, and direction angles) for the one-channel infrared pyrometer with the optimized measurement spectral response. The analysis can be used to improve radiation temperature measurements of semitransparent ZnS materials in applications. PMID:25322390

Fu, Tairan; Liu, Jiangfan; Zong, Anzhou

2014-10-10

24

A low aspect ratio tokamak transmutation system  

Microsoft Academic Search

A low aspect ratio tokamak transmutation system is proposed as an alternative application of fusion energy on the basis of a review of previous studies. This system includes: (1) a low aspect ratio tokamak as fusion neutron driver, (2) a radioactivity-clean nuclear power system as blanket, and (3) a novel concept of liquid metal centre conductor post as part of

L. J. Qiu; Y. C. Wu; B. J. Xiao; Q. Xu; Q. Y. Huang; B. Wu; Y. X. Chen; W. N. Xu; Y. P. Chen; X. P. Liu

2000-01-01

25

Evaluation of Raytek infrared pyrometer for continuous propellant temperature measurement  

NASA Technical Reports Server (NTRS)

The primary purpose of this evaluation was to determine if the Raytek IR pyrometer that was installed in the 600 gallon propellant mixers could be used to provide a continuous, accurate, reliable measurement of the propellant temperature during mixing. The Raytek infrared sensor is not recommended to be used for controlling propellant temperature nor for inspection buy-off. The first part of the evaluation was to determine the accuracy of the sensor in measuring the propellant temperature. The second part was to determine the reliability of the air purge design in preventing contamination of the IR window.

Dykstra, Mark D.

1990-01-01

26

High-resolution surface temperature measurements on rotating turbine blades with an infrared pyrometer  

NASA Technical Reports Server (NTRS)

A high-resolution pyrometer was developed and tested on a modified turbine engine. The pyrometer was used to obtain temperature profiles of the viewed surface of turbine blades in the engine at tip speeds up to 366 meters per second. The combination of coherent fiber optics, a silicon avalanche detector, and high-speed electronics enabled surface resolution of a spot diameter of 0.05 centimeter. The data, in the form of temperature profiles, was obtained in near real time as a hard copy output from a computer display terminal. Temperatures measured with the pyrometer and with thermocouples agreed within 2 percent at temperatures between 977 to 1144 K.

Uguccini, O. W.; Pollack, F. G.

1976-01-01

27

Ratio control system for continuously variable transmission  

SciTech Connect

This patent describes a ratio control system for a continuously variable transmission which performs a feedback control wherein an integral control gain and a proportional control gain are varied depending upon the level of a line pressure that is used to actuate a pulley unit during shifting operation.

Oshiage, K.

1987-10-27

28

MEASUREMENTS OF INTERFACE SUPERCOOLING WITH THE OPTICAL PYROMETER IN CRYSTAL GROWTH FROM THE MELT1  

Microsoft Academic Search

Construction and parameters of an optical high-resolution pyrometer, designed for interface supercooling ?T measurement, are described. Supercooling is determined by measuring of interface brightness temperature ?b through the growing semitransparent crystal. The results of in situ supercooling measurement at Bi3Ge4O12 crystal growth from melt, obtained with the use of a pyrometer, are discussed. The influence of thermal conditions on the

S. V. Bykova; V. S. Dozhdikov; V. D. Golyshev; M. A. Gonik; V. A. Petrov; V. N. Senchenko; V. B. Tsvetovsky

29

Evaluation and comparison of three IR detectors and three amplifier designs for a new, high-speed IR pyrometer  

SciTech Connect

At Los Alamos National Laboratory (LANL), a high-speed, four-wavelength, infrared (IR) pyrometer has been used for surface temperature measurements in shock-physics experiments for several years. The pyrometer uses solid state detectors and a single fiber-optic cable for transmission of light from the target surface to the detectors. This instrument has recently been redesigned for an upcoming experiment at the Nevada Test Site (NTS). Three different IR detectors (two HgCdTe variants as well as the existing InSb chip) were compared for sensitivity, signal-to-noise ratio, and bandwidth. Of major concern was detector amplifier recovery time from overload saturation. In shock physics experiments, a short but very bright precursor frequently accompanies shock breakout (often from trapped air). This precursor can saturate the amplifier and may ''swamp-out'' the signal of interest before the amplifier recovers. With this in mind, we evaluated two new amplifier designs by the Perry Amplifier Company for linearity, signal-to-noise characteristics, gain, and saturation recovery time. This paper describes experimental setup for detector comparison and results obtained. Furthermore, we discuss new amplifier design and suitability for highspeed infrared pyrometry in shock physics experiments.

J.A. Young, S. Borrora, A.W. Obst, J.R. Payton, A. Seifter

2005-01-01

30

Measuring Isotope Ratios Across the Solar System  

NASA Technical Reports Server (NTRS)

Stable isotope ratios in C, H, N, O and S are powerful indicators of a wide variety of planetary geophysical processes that can identify origin, transport, temperature history, radiation exposure, atmospheric escape, environmental habitability and biology [1]. For the Allan Hills 84001 meteorite, for example, the (sup 1)(sup 3)C/(sup 1)(sup 2)C ratio identifies it as a Mars (SNC) meteorite; the ??K/??Ar ratio tells us the last time the rock cooled to solid, namely 4 Gya; isotope ratios in (sup 3)He, (sup 2)(sup 1)Ne and (sup 3)?Ar show it was in space (cosmic ray exposure) for 10-20 million years; (sup 1)?C dating that it sat in Antarctica for 13,000 years before discovery; and clumped isotope analysis of (sup 1)?O(sup 1)(sup 3)C(sup 1)?O in its carbonate that it was formed at 18+/-4 ?C in a near-surface aqueous environment [2]. Solar System Formation

Webster, Chris R.; Mahaffy, Paul R.

2012-01-01

31

CO (Carbon Monoxide Mixing Ratio System) Handbook  

SciTech Connect

The main function of the CO instrument is to provide continuous accurate measurements of carbon monoxide mixing ratio at the ARM SGP Central Facility (CF) 60-meter tower (36.607 °N, 97.489 °W, 314 meters above sea level). The essential feature of the control and data acquisition system is to record signals from a Thermo Electron 48C and periodically calibrate out zero and span drifts in the instrument using the combination of a CO scrubber and two concentrations of span gas (100 and 300 ppb CO in air). The system was deployed on May 25, 2005.

Biraud, S

2011-02-23

32

Hydraulic system for a ratio change transmission  

DOEpatents

Disclosed is a drive assembly (10) for an electrically powered vehicle (12). The assembly includes a transaxle (16) having a two-speed transmission (40) and a drive axle differential (46) disposed in a unitary housing assembly (38), an oil-cooled prime mover or electric motor (14) for driving the transmission input shaft (42), an adapter assembly (24) for supporting the prime mover on the transaxle housing assembly, and a hydraulic system (172) providing pressurized oil flow for cooling and lubricating the electric motor and transaxle and for operating a clutch (84) and a brake (86) in the transmission to shift between the two-speed ratios of the transmission. The adapter assembly allows the prime mover to be supported in several positions on the transaxle housing. The brake is spring-applied and locks the transmission in its low-speed ratio should the hydraulic system fail. The hydraulic system pump is driven by an electric motor (212) independent of the prime mover and transaxle.

Kalns, Ilmars (Northville, MI)

1981-01-01

33

Flexible Conversion Ratio Fast Reactor Systems Evaluation  

SciTech Connect

Conceptual designs of lead-cooled and liquid salt-cooled fast flexible conversion ratio reactors were developed. Both concepts have cores reated at 2400 MWt placed in a large-pool-type vessel with dual-free level, which also contains four intermediate heat exchanges coupling a primary coolant to a compact and efficient supercritical CO2 Brayton cycle power conversion system. Decay heat is removed passively using an enhanced Reactor Vessel Auxiliary Cooling System and a Passive Secondary Auxiliary Cooling System. The most important findings were that (1) it is feasible to design the lead-cooled and salt-cooled reactor with the flexible conversion ratio (CR) in the range of CR=0 and CR=1 n a manner that achieves inherent reactor shutdown in unprotected accidents, (2) the salt-cooled reactor requires Lithium thermal Expansion Modules to overcme the inherent salt coolant's large positive coolant temperature reactivity coefficient, (3) the preferable salt for fast spectrum high power density cores is NaCl-Kcl-MgCl2 as opposed to fluoride salts due to its better themal-hydraulic and neutronic characteristics, and (4) both reactor, but attain power density 3 times smaller than that of the sodium-cooled reactor.

Neil Todreas; Pavel Hejzlar

2008-06-30

34

Fiber optic pyrometer and its application in hot-blast stove temperature measurement  

NASA Astrophysics Data System (ADS)

Introduced in this paper are a technique of fiber optic dual-wavelength pyrometer and its principle, structure and characteristics. It was successfully applied under the hostile environment in hot-blast stoves to measure high-temperature. The efforts to overcome all difficulties, such as pressure, water vapor, and probe bend caused by thermal expansion, are reported in details. The resulting device is reliable, stable and accurate, and has immunity to harmful gas corrosion. The proposed pyrometer has a long lifetime. Therefore, it can replace the conventional thermo-electric-couple for temperature measurement in a blast furnace.

Li, Weilai; Jiang, Desheng; Zhu, Weijia

2004-03-01

35

Multi-channel optical pyrometer for sub-nanosecond temperature measurements at NDCX-I/II  

SciTech Connect

We present a detailed technical description of a fast multi-channel pyrometer designed for warm-dense-matter (WDM) experiments with intense heavy ion beams at the neutralized-drift-compression-experiment linear accelerator (NDCX-I/II) at Lawrence Berkeley National Laboratory (LBNL). The unique features of the described instrument are its sub-nanosecond temporal resolution (100 ps rise-time) and a broad range, 1,500 K - 12,000 K of measurable brightness temperatures in the visible and near-infrared regions of the spectrum. The working scheme, calibration procedure, experimental data obtained with the pyrometer and future applications are presented.

Ni, P.A.; Bieniosek, F.M.; Waldron, W.L.

2011-04-13

36

The Period-Ratio and Mass-Ratio Correlation in Extra-Solar Multiple Planetary Systems  

E-print Network

Employing the data from orbital periods and masses of extra-solar planets in 166 multiple planetary systems, the period-ratio and mass-ratio of adjacent planet pairs are studied. The correlation between the period-ratio and mass-ratio is confirmed and found to have a correlation coefficient of 0.5303 with a 99% confidence interval (0.3807, 0.6528). A comparison with the distribution of synthetic samples from a Monte Carlo simulation reveals the imprint of planet-planet interactions on the formation of adjacent planet pairs in multiple planetary systems.

Jiang, Ing-Guey; Hung, Wen-Liang

2015-01-01

37

A cooled-gas pyrometer for use in hypersonic engine testing  

NASA Technical Reports Server (NTRS)

A cooled-gas pyrometer designed for application in a hypersonic research engine program was fabricated and tested. Design and operational considerations and calibration data are presented. The probe was tested in a rocket-engine exhaust stream operating at Mach 2 and 2300 K. Test temperature measurements agreed to within 2 percent with a radiation shielded thermocouple probe.

Glawe, G. E.

1973-01-01

38

Fast six-channel pyrometer for warm-dense-matter experiments with intense heavy-ion beams  

SciTech Connect

This paper describes a fast multi-channel radiation pyrometer that was developed for warmdense-matter experiments with intense heavy ion beams at Gesellschaft fur Schwerionenforschung mbH (GSI). The pyrometer is capable of measuring of brightness temperatures from 2000 K to 50000 K, at 6 wavelengths in visible and near-infrared parts of spectrum, with 5 nanosecond temporal resolution and several micrometers spatial resolution. The pyrometer's spectral discrimination technique is based on interference filters, which act as filters and mirrors to allow for simultaneous spectral discrimination of the same ray at multiple wavelengths.

Ni, P.A.; Kulish, M.I.; Mintsev, V.; Nikolaev, D.N.; Ternovoi, V.Ya.; Hoffmann, D.H.H.; Udrea, S.; Tahir, N.A.; Varentsov, D.; Hug, A.

2008-12-01

39

Elevated sacroilac joint uptake ratios in systemic lupus erythematosus  

SciTech Connect

Sacroiliac joint radiographs and radionuclide sacroiliac joint uptake ratios were obtained on 14 patients with active systemic lupus erythematosus. Elevated joint ratios were found unilaterally in two patients and bilaterally in seven patients when their lupus was active. In patients whose disease became quiescent, the uptake ratios returned to normal. Two patients had persistently elevated ratios with continued clinical and laboratory evidence of active lupus. Mild sacroiliac joint sclerosis and erosions were detected on pelvic radiographs in these same two patients. Elevated quantitative sacroiliac joint uptake ratios may occur as a manifestation of active systemic lupus erythematosus.

De Smet, A.A.; Mahmood, T.; Robinson, R.G.; Lindsley, H.B.

1984-08-01

40

Transmission ratio control system for a continuously variable transmission  

SciTech Connect

This patent describes a control system for a continuously variable transmission for transmitting power of an internal combustion engine, the transmission having a drive pulley including a hydraulically shiftable first disc and a hydraulic cylinder for operating the disc, a driven pulley including a hydraulically shiftable second disc and a hydraulic cylinder for operating the second disc, and a belt engaged with both pulleys, the control system comprising a hydraulic circuit including a pump for supplying oil to both the hydraulic cylinders, a transmission ratio control valve including a shiftable spool for controlling the oil supplied to the cylinder of the drive pulley to change transmission ratio of the transmission to a desired transmission ratio, shifting means for shifting the spool, sensing means for sensing operating conditions of the engine and the transmission and for producing condition signals dependent on the conditions, actual transmission ratio signal producing means responsive to the condition signals for producing an actual transmission ratio signal corresponding to the actual transmission ratio of the transmission, desired transmision ratio signal producing means responsive to the condition signals for producing a desired transmission ratio signal corresponding to a desired transmission ratio, transmission ratio changing speed signal producing means responsive to the actual transmission ratio signal and to the desired transmission ratio signal for producing a transmission ratio changing rate signal corresponding to a transmission ratio changing rate, and control signal producing means responsive to the transmission ratio changing rate signal for producing a control signal for operating the shifting means to shift the spool dependent on the transmission ratio changing rate for changing the actual transmission ratio of the transmission to the desired transmission ratio.

Tanaka, H.

1989-05-30

41

Pyrometer mount for a closed-circuit thermal medium cooled gas turbine  

DOEpatents

A steam-cooled second-stage nozzle segment has an outer band and an outer cover defining a plenum therebetween for receiving cooling steam for flow through the nozzles to the inner band and cover therefor and return flow through the nozzles. To measure the temperature of the buckets of the stage forwardly of the nozzle stage, a pyrometer boss is electron beam-welded in an opening through the outer band and TIG-welded to the outer cover plate. By machining a hole through the boss and seating a linearly extending tube in the boss, a line of sight between a pyrometer mounted on the turbine frame and the buckets is provided whereby the temperature of the buckets can be ascertained. The welding of the boss to the outer band and outer cover enables steam flow through the plenum without leakage, while providing a line of sight through the outer cover and outer band to measure bucket temperature.

Jones, Raymond Joseph (Duanesburg, NY); Kirkpatrick, Francis Lawrence (late of Galway, NY); Burns, James Lee (Schenectady, NY); Fulton, John Robert (Clifton Park, NY)

2002-01-01

42

Two-Step Calibration of a Multiwavelength Pyrometer for High Temperature Measurement Using a Quartz Lamp  

NASA Technical Reports Server (NTRS)

There is no theoretical upper temperature limit for pyrometer application in temperature measurements. NASA Glenn's multiwavelength pyrometer can make measurements over wide temperature ranges. However, the radiation spectral response of the pyrometer's detector must be calibrated before any temperature measurement is attempted, and it is recommended that calibration be done at temperatures close to those for which measurements will be made. Calibration is a determination of the constants of proportionality at all wavelengths between the detector's output (voltage) and its input signals (usually from a blackbody radiation source) in order to convert detector output into radiation intensity. To measure high temperatures, the detectors are chosen to be sensitive in the spectral range from 0.4 to 2.5 micrometers. A blackbody furnace equilibrated at around 1000 C is often used for this calibration. Though the detector may respond sensitively to short wavelengths radiation, a blackbody furnace at 1000 C emits only feebly at very short wavelengths. As a consequence, the calibration constants that result may not be the most accurate. For pyrometry calibration, a radiation source emitting strongly at the short wavelengths is preferred. We have chosen a quartz halogen lamp for this purpose.

Ng, Daniel

2001-01-01

43

Methodology on high ratio multiple configuration systems in image sensor  

NASA Astrophysics Data System (ADS)

The method of a multiple configuration on high ratio systems in image sensor is an important subject. In such an experimental configuration, for aim to break through to large ratio multiple configuration systems bottlenecks, achieve the field of continuous transformation, effect system close to the theoretical limit and configuration dexterity, such as the purpose, method in the design of the integrated sensor system process, the core technology of such a system are thoroughly analyzed and the factors important to the compromise. Theory is studied based on the theory of Gaussian optical system error distribution and comprehensive balancing algorithm; Global optimization method, developed at a system design thought and the optimization model. Results solved the MTF matching problem, research and evaluations shows that the zoom ratio of more than one hundred results in system MTF and so on as qualitative criterion to achieve requirements.

Liu, Hua; Ding, Quanxin; Zhou, Liwei

2014-12-01

44

Evaluation and improvement in the accuracy of a charge-coupled-device-based pyrometer for temperature field measurements of continuous casting billets.  

PubMed

This paper presents a radiometric high-temperature field measurement model based on a charge-coupled-device (CCD). According to the model, an intelligent CCD pyrometer with a digital signal processor as the core is developed and its non-uniformity correction algorithm for reducing the differences in accuracy between individual pixel sensors is established. By means of self-adaptive adjustment for the light-integration time, the dynamic range of the CCD is extended and its accuracy in low-temperature range is improved. The non-uniformity correction algorithm effectively reduces the accuracy differences between different pixel sensors. The performance of the system is evaluated through a blackbody furnace and an integrating sphere, the results of which show that the dynamic range of 400 K is obtained and the accuracy in low temperature range is increased by 7 times compared with the traditional method based on the fixed light-integration time. In addition, the differences of accuracy between the on-axis pixel and the most peripheral pixels are decreased from 19.1 K to 2.8 K. Therefore, this CCD pyrometer ensures that the measuring results of all pixels tend to be equal-accuracy distribution across the entire measuring ranges. This pyrometric system has been successfully applied to the temperature field measurements in continuous casting billets. PMID:23822369

Bai, Haicheng; Xie, Zhi; Zhang, Yuzhong; Hu, Zhenwei

2013-06-01

45

Deep, Low Mass Ratio Overcontact Binary Systems. V. The Lowest Mass Ratio Binary V857 Herculis  

NASA Astrophysics Data System (ADS)

Charge-coupled device (CCD) photometric light curves in the B, V, and R bands of the complete eclipsing binary star V857 Her are presented. It is shown that the light curves of the W UMa-type binary are symmetric and of A type according to Binnendijk's classification. Our four epochs of light minimum along with others compiled from the literature were used to revise the period and study the period change. Weak evidence indicates that the orbital period of V857 Her may show a continuous increase at a rate of dP/dt=+2.90×10-7 days yr-1. The photometric parameters of the system were determined with the 2003 version of the Wilson-Devinney code. It is shown that V857 Her is a deep overcontact binary system with f=83.8%+/-5.1%. The derived mass ratio of q=0.06532+/-0.0002 suggests that it has the lowest mass ratio among overcontact binary systems. As the orbital period increases, the decrease of the mass ratio will cause it to evolve into a single rapidly rotating star when it meets the more familiar criterion that the orbital angular momentum be less than 3 times the total spin angular momentum. To understand the evolutionary state of the system, long-term photometric monitoring and spectroscopic observations will be required.

Qian, S.-B.; Zhu, L.-Y.; Soonthornthum, B.; Yuan, J.-Z.; Yang, Y.-G.; He, J.-J.

2005-09-01

46

The distribution of period ratios in Kepler planetary systems  

NASA Astrophysics Data System (ADS)

Kepler's multi-planet systems are a valuable tool to understand the architectures and dynamics of the inner parts of planetary systems. I present an analysis of the distribution of orbital period ratios from candidate systems identified in the Quarter 8 catalog (Burke et al. 2014). This distribution is corrected for the effects of geometric transit probabilities and the completeness of the data reduction pipeline. We find that the distribution of period ratios falls as a power law with exponent -1.26 ± 0.05. We also identify a new, statistically significant feature near a period ratio of 2.2. These observations may provide insights into the formation and evolution of these systems.

Steffen, Jason H.; Hwang, Jason A.

2015-01-01

47

Reduction of measurement system variation using the Discrimination Ratio  

NASA Astrophysics Data System (ADS)

The standard deviation of Test-Retest error provides an absolute measure of the error introduced by the measurement system. It does not, however, characterize the relative usefulness of the measurement system for measuring a specific product. Such a measure is of particular interest in a production environment. To determine the relative usefulness of a measurement system, one must have an estimate of product variation and a method for comparing Test-Retest error with product variation. In this paper we will discuss the use of the Discrimination Ratio to characterize and evaluate the relative usefulness of a given measurement system in a production environment. In particular, we will calculate the Discrimination Ratio for a 4-point probe system and investigate the effect of probe head tip radii on the overall system variation. Results indicate that each implant recipe has an optimum four point probe head as determined by the maximization of the Discrimination Ratio. Other four point probe heads could be used if larger system variations are tolerated. The Discrimination Ratio was found to be a critical parameter when interpreting results to minimize measurement system variations.

Nunes, J.; Cherekdjian, S.

1995-03-01

48

Design and fabrication of an infrared optical pyrometer ASIC as a diagnostic for shock physics experiments  

NASA Astrophysics Data System (ADS)

Optical pyrometry is the sensing of thermal radiation emitted from an object using a photoconductive device to convert photons into electrons, and is an important diagnostic tool in shock physics experiments. Data obtained from an optical pyrometer can be used to generate a blackbody curve of the material prior to and after being shocked by a high speed projectile. The sensing element consists of an InGaAs photodiode array, biasing circuitry, and multiple transimpedance amplifiers to boost the weak photocurrent from the noisy dark current into a signal that can eventually be digitized. Once the circuit elements have been defined, more often than not commercial-off-the-shelf (COTS) components are inadequate to satisfy every requirement for the diagnostic, and therefore a custom application specific design has to be considered. This thesis outlines the initial challenges with integrating the photodiode array block with multiple COTS transimpedance amplifiers onto a single chip, and offers a solution to a comparable optical pyrometer that uses the same type of photodiodes in conjunction with a re-designed transimpedance amplifier integrated onto a single chip. The final design includes a thorough analysis of the transimpedance amplifier along with modeling the circuit behavior which entails schematics, simulations, and layout. An alternative circuit is also investigated that incorporates an approach to multiplex the signals from each photodiode onto one data line and not only increases the viable real estate on the chip, but also improves the behavior of the photodiodes as they are subjected to less thermal load. The optical pyrometer application specific integrated circuit (ASIC) for shock physic experiments includes a transimpedance amplifier (TIA) with a 100 k? gain operating at bandwidth of 30 MHz, and an input-referred noise RMS current of 50 nA that is capable of driving a 50 ? load.

Gordon, Jared

49

Rapid exchange effects on isotope ratios in groundwater systems: 2. Flow investigation using Sr isotope ratios  

NASA Astrophysics Data System (ADS)

Sr isotope ratios were measured in groundwater, whole rock digestions, and cation exchange extracts from a clay-rich groundwater system at Ernest O. Lawrence Berkeley National Laboratory and were used to constrain flow velocities and search for preferential flow paths. In the Orinda formation siltstone, 87Sr/86Sr increases strongly over tens of meters along presumed flow paths, indicating slow groundwater flow. Dissolved Sr is close to isotopic equilibrium with the exchangeable Sr in the clays, and the observed 87Sr/86Sr increase is interpreted as a cation exchange front moving slowly through the unit combined with dissolution of minerals with relatively high 87Sr/86Sr ratios. The data are inverted using a one-dimensional transport-dissolution-exchange model; the results indicate long-term average flow velocities of less than 0.2 m/yr which are consistent with 14C measurements. The data suggest a lack of strong preferential flow paths through this unit.

Johnson, Thomas M.; Depaolo, Donald J.

1997-01-01

50

Heavy ion beam probe systems for tight aspect ratio tokamaks  

SciTech Connect

We discuss the specific features of the application of heavy ion beam probe (HIBP) systems to tight aspect ratio tokamaks. We present and compare the HIBP projects for the TUMAN-3, GLOBUS, and COMPASS, where the inner part of the plasma is not available for regular chord diagnostics, so the HIBP becomes very desirable. All existing tight aspect ratio facilities and projects have a low (less than 1.9 T) toroidal field that requires a comparatively low beam energy range. The natural elongation and triangularity in tight aspect ratio tokamaks require an accurate calculation of the three-dimensional magnetic field for probing optimization. In comparison with traditional tokamaks, the detector grids have a wider energy interval. In general, the trajectories and detector grids for tight aspect ratio tokamaks become similar to the stellarator ones. Traditional and new probing schemes are suggested and discussed. {copyright} {ital 1997 American Institute of Physics.}

Melnikov, A.V.; Zimeleva, L.G. [Russian Research Centre Kurchatov Institute, Moscow (Russia)] [Russian Research Centre Kurchatov Institute, Moscow (Russia); Krupnik, L.I.; Nedzelskij, I.S.; Trofimenko, Y.V. [Ukrainian Research Centre KhIPT, Kharkov (Ukraine)] [Ukrainian Research Centre KhIPT, Kharkov (Ukraine); Minaev, V.B. [Saint-Petersburg Institute Physics and Technology, Saint-Petersburg (Russia)] [Saint-Petersburg Institute Physics and Technology, Saint-Petersburg (Russia)

1997-01-01

51

Transmission ratio control system for a continuously variable transmission  

SciTech Connect

This patent describes a control system for a continuously variable transmission for transmitting power of an internal combustion engine controlled by an accelerator pedal, the transmission comprising a drive pulley having a hydraulically shiftable first disc and a first hydraulic cylinder for operating the disc, a driven pulley having a hydraulically shiftable second disc and a second hydraulic cylinder for operating the second disc, and a belt engaged with both pulleys, the control system including a first hydraulic circuit having a pump for supplying oil to both of the hydraulic cylinders, a transmission ratio control valve having a spool for controlling the oil supplied to the first hydraulic cylinder of the drive pulley, shifting means for shifting the spool, sensing means for sensing operating conditions of the engine and the transmission, actual transmission ratio producing means responsive to the sensed operating conditions for producing means responsive to the sensed signal representing the actual transmission ratio of the transmission.

Miyawaki, M

1989-05-23

52

The period ratio distribution of Kepler's candidate multiplanet systems  

E-print Network

We calculate and analyze the distribution of period ratios observed in systems of Kepler exoplanet candidates including studies of both adjacent planet pairs and all planet pairs. These distributions account for both the geometrical bias against detecting more distant planets and the effects of incompleteness due to planets missed by the data reduction pipeline. In addition to some of the known features near first-order mean-motion resonances (MMR), there is a significant excess of planet pairs with period ratios near 2.2. The statistical significance of this feature is assessed using Monte Carlo simulation. We also investigate the distribution of period ratios near first-order MMR and compare different quantities used to measure this distribution. We find that beyond period ratios of ~2.5, the distribution of all period ratios follows a power-law with an exponent -1.26 +/- 0.05. We discuss implications that these results may have on the formation and dynamical evolution of Kepler-like planetary systems---sys...

Steffen, Jason H

2014-01-01

53

An evaluation of ratio systems in radioecological studies  

SciTech Connect

Replicate samples of soil, Juncus squarrosus and Calluna vulgaris were taken within a grid system on an organic peatland soil site in Ireland. A similar sampling survey was carried out on an organic rich forest soil site in Sweden, where Vaccinium myrtillus and Vaccinium vitis-idaea with corresponding soil samples were taken within a Picea abies stand. The data were used to investigate the relationship between soil and plant {sup 137}Cs content and to examine the validity of using ratios to describe this relationship. Findings from both countries were in agreement. There were no significant changes in plant {sup 137}Cs concentration associated with increasing soil content. When data from both countries were merged and treated as a single data set, a significant overall positive correlation (95% confidence level) between soil and plant {sup 137}Cs levels was observed. Concentration ratios and transfer factors were calculated for {sup 137}Cs and {sup 40}K uptake from soils to plants. Both ratio types exhibited a clearly defined decrease associated with increasing soil concentrations for both radionuclides. Findings demonstrate serious problems with the use of ratios for the evaluation of radionuclide transfer. 28 refs., 4 figs., 10 tabs.

McGee, E.J.; Synnott, H.J.; Colgan, P.A. [Radiological Protection Institute of Ireland, Dublin (Ireland)] [and others

1996-02-01

54

[Development of multi-target multi-spectral high-speed pyrometer].  

PubMed

The plume temperature of a solid propellant rocket engine (SPRE) is a fundamental parameter in denoting combustion status. It is necessary to measure the temperature along both the axis and the radius of the engine. In order to measure the plume temperature distribution of a solid propellant rocket engine, the multi-spectral thermometry has been approved. Previously the pyrometer was developed in the Harbin Institute of Technology of China in 1999, which completed the measurement of SPRE plume temperature and its distribution with multi-spectral technique in aerospace model development for the first time. Following this experience, a new type of multi-target multi-spectral high-speed pyrometer used in the ground experiments of SPRE plume temperature measurement was developed. The main features of the instrument include the use of a dispersing prism and a photo-diode array to cover the entire spectral band of 0.4 to 1.1 microm. The optic fibers are used in order to collect and transmit the thermal radiation fluxes. The instrument can measure simultaneously the temperature and emissivity of eight spectra for six uniformly distributed points on the target surface, which are well defined by the hole on the field stop lens. A specially designed S/H (Sample/Hold) circuit, with 48 sample and hold units that were triggered with a signal, measures the multi-spectral and multi-target outputs. It can sample 48 signals with a less than 10ns time difference which is most important for the temperature calculation. PMID:19271529

Xiao, Peng; Dai, Jing-Min; Wang, Qing-Wei

2008-11-01

55

Transmission ratio control system for a continuously variable transmission  

SciTech Connect

This patent describes a control system for a continuously variable transmission for transmitting the power of an internal combustion engine to driving wheels of a motor vehicle through a clutch, having a drive pulley including a hydraulically shiftable disc and a first hydraulic cylinder for shifting the disc. A driven pulley includes a hydraulically shiftable disc and a second hydraulic cylinder for operating the disc of the driven pulley. A belt is engaged with both pulleys. A transmission ratio control valve has ports and a spool and a line pressure control valve has ports and a spool. A first hydraulic circuit has a pump for supplying oil to the first and second cylinders through the line pressure control valve which controls line pressure and the transmission ratio control valve. The system comprises: detecting means for detecting load on the engine and for producing a load signal; first means responsive to the load signal for producing a desired line pressure signal; second means responsive to the desired line pressure signal for shifting the spool of the line pressure control valve so as to provide control the line pressure; detecting means for detecting a stop of the vehicle and producing a stop signal; third means responsive to the stop signal for increasing the line pressure so as to operate the second hydraulic cylinder to increase the transmission ratio.

Morimoto, Y.; Tezuka, K.

1987-11-24

56

Revolution speed ratio control system for a continuously variable transmission  

SciTech Connect

This patient describes revolution speed ratio control system for a continuously variable transmission comprising a driving pulley provided on an input shaft; a driven pulley provided on an output shaft disposed in parallel with the input shaft; an endless belt wound on both the pulleys; each of the pulleys comprising a fixed member secured to the input or output shaft and having a conical surface, and a movable member which has a conical surface facing that of the fixed member and is provided so that the movable member is rotated together with the input or output shaft and can be slid on the shaft in the axial direction thereof; and the endless belt has both its oblique side surfaces frictionally engaged with the conical surfaces of the fixed and movable members; an electronic control circuit including a means for calculating the actual revolution speed ratio between the driving and driven pulleys of the transmission, a means for generating a first electric control signal corresponding to the difference between the actual revolution speed ratio and an aimed revolution speed ratio between the pulleys determined by information of the input torque of the input shaft and required torque for the output shaft, and a means for generating a second electric control signal determined by the sum of an electric signal corresponding to the actual revolution speed ratio and an electric signal corresponding to the difference; and a hydraulic control circuit including a pressure oil source, a first cylinder which is provided on the input shaft and supplied with working oil from the pressure oil source to push the movable member of the driving pulley toward the fixed member thereof.

Hattori, K.; Suzuki, H.; Yamaguchi, H.; Ogasawara, T.

1988-12-13

57

Extreme oxygen isotope ratios in the early Solar System.  

PubMed

The origins of the building blocks of the Solar System can be studied using the isotopic composition of early planetary and meteoritic material. Oxygen isotopes in planetary materials show variations at the per cent level that are not related to the mass of the isotopes; rather, they result from the mixture of components having different nucleosynthetic or chemical origins. Isotopic variations reaching orders of magnitude in minute meteoritic grains are usually attributed to stellar nucleosynthesis before the birth of the Solar System, whereby different grains were contributed by different stars. Here we report the discovery of abundant silica-rich grains embedded in meteoritic organic matter, having the most extreme 18O/16O and 17O/16O ratios observed (both approximately 10(-1)) together with a solar silicon isotopic composition. Both O and Si isotopes indicate a single nucleosynthetic process. These compositions can be accounted for by one of two processes: a single exotic evolved star seeding the young Solar System, or irradiation of the circumsolar gas by high energy particles accelerated during an active phase of the young Sun. We favour the latter interpretation, because the observed compositions are usually not expected from nucleosynthetic processes in evolved stars, whereas they are predicted by the selective trapping of irradiation products. PMID:16163350

Aléon, Jérôme; Robert, François; Duprat, Jean; Derenne, Sylvie

2005-09-15

58

21 CFR 862.1455 - Lecithin/sphingomyelin ratio in amniotic fluid test system.  

Code of Federal Regulations, 2010 CFR

...2010-04-01 2010-04-01 false Lecithin/sphingomyelin ratio in amniotic fluid...Chemistry Test Systems § 862.1455 Lecithin/sphingomyelin ratio in amniotic fluid test system. (a) Identification. A lecithin/sphingomyelin ratio in amniotic...

2010-04-01

59

Control system and method for a power delivery system having a continuously variable ratio transmission  

DOEpatents

A control system and method for a power delivery system, such as in an automotive vehicle, having an engine coupled to a continuously variable ratio transmission (CVT). Totally independent control of engine and transmission enable the engine to precisely follow a desired operating characteristic, such as the ideal operating line for minimum fuel consumption. CVT ratio is controlled as a function of commanded power or torque and measured load, while engine fuel requirements (e.g., throttle position) are strictly a function of measured engine speed. Fuel requirements are therefore precisely adjusted in accordance with the ideal characteristic for any load placed on the engine.

Frank, Andrew A. (1034 Hillside Ave., Madison, WI 53705)

1984-01-01

60

Control system and method for a power delivery system having a continuously variable ratio transmission  

DOEpatents

A control system and method for a power delivery system, such as in an automotive vehicle, having an engine coupled to a continuously variable ratio transmission (CVT). Totally independent control of engine and transmission enable the engine to precisely follow a desired operating characteristic, such as the ideal operating line for minimum fuel consumption. CVT ratio is controlled as a function of commanded power or torque and measured load, while engine fuel requirements (e.g., throttle position) are strictly a function of measured engine speed. Fuel requirements are therefore precisely adjusted in accordance with the ideal characteristic for any load placed on the engine. 4 figs.

Frank, A.A.

1984-07-10

61

Simulating extreme-mass-ratio systems in full general relativity  

NASA Astrophysics Data System (ADS)

We introduce a new method for numerically evolving the full Einstein field equations in situations where the spacetime is dominated by a known background solution. The technique leverages the knowledge of the background solution to subtract off its contribution to the truncation error, thereby more efficiently achieving a desired level of accuracy. We demonstrate the method by applying it to the radial infall of a solar-type star into supermassive black holes with mass ratios ?106. The self-gravity of the star is thus consistently modeled within the context of general relativity, and the star’s interaction with the black hole computed with moderate computational cost, despite the over five orders of magnitude difference in gravitational potential (as defined by the ratio of mass to radius). We compute the tidal deformation of the star during infall, and the gravitational wave emission, finding the latter is close to the prediction of the point-particle limit.

East, William E.; Pretorius, Frans

2013-05-01

62

An acoustic pyrometer system for tomographic thermal imaging in power plant boilers  

Microsoft Academic Search

The paper presents an acoustic pyrometry method for the reconstruction of temperature maps inside power plant boilers. It is based on measuring times-of-flight of acoustic waves along a number of straight paths in a cross-section of the boiler; via an integral relationship, these times depend on the temperature of the gaseous medium along the paths. On this basis, 2D temperature

Mauro Bramanti; Emanuele A. Salerno; Anna Tonazzini; Sauro Pasini; Antonio Gray

1996-01-01

63

Air/fuel ratio monitoring system in ic engine using oxygen sensor  

SciTech Connect

A system is described for monitoring the air/fuel ratio of an air-fuel mixture supplied to an internal combustion engine. The system consists of: a concentration cell type oxygen sensor means disposed in an exhaust passage of the engine, the oxygen sensor having a laminate of an inner electrode layer, a microscopically porous layer of an oxygen ion conductive solid electrolyte, and an outer electrode layer exposed to exhaust gas, the sensor means producing an output which becomes a high-level voltage signal when the air/fuel ratio is below the stoichiometric ratio of the air-fuel mixture, and which becomes a low-level voltage signal when the air/fuel ratio is above the stoichiometric ratio; judgement means for producing an air/fuel ratio signal which indicates whether the air/fuel ratio is above or below the stoichiometric ratio by comparing the output of the oxygen sensor with a reference voltage; modulating means for producing a modulated voltage signal by subtracting a first fixed voltage from the output of the oxygen sensor when the air/fuel ratio signal indicates that the air/fuel ratio is below the stiochiometric ratio and by adding a fixed definite voltage to the output of the oxygen sensor when the air/fuel ratio signal indicates that the air/fuel ratio is above the stoichiometric ratio; and smoothing means, having a variable time constant, for smoothing the modulated voltage signal to thereby produce a smoothed voltage and for supplying the smoothed voltage to the judgement means as the reference voltage; control means for varying the time constant of the smoothing means as a function of a change in the output of the oxygen sensor.

Kithara, T.; Sone, K.

1986-07-22

64

Mortality, fertility, and the OY ratio in a model hunter-gatherer system.  

PubMed

An agent-based model (ABM) is used to explore how the ratio of old to young adults (the OY ratio) in a sample of dead individuals is related to aspects of mortality, fertility, and longevity experienced by the living population from which the sample was drawn. The ABM features representations of rules, behaviors, and constraints that affect person- and household-level decisions about marriage, reproduction, and infant mortality in hunter-gatherer systems. The demographic characteristics of the larger model system emerge through human-level interactions playing out in the context of "global" parameters that can be adjusted to produce a range of mortality and fertility conditions. Model data show a relationship between the OY ratios of living populations (the living OY ratio) and assemblages of dead individuals drawn from those populations (the dead OY ratio) that is consistent with that from empirically known ethnographic hunter-gatherer cases. The dead OY ratio is clearly related to the mean ages, mean adult mortality rates, and mean total fertility rates experienced by living populations in the model. Sample size exerts a strong effect on the accuracy with which the calculated dead OY ratio reflects the actual dead OY ratio of the complete assemblage. These results demonstrate that the dead OY ratio is a potentially useful metric for paleodemographic analysis of changes in mortality and mean age, and suggest that, in general, hunter-gatherer populations with higher mortality, higher fertility, and lower mean ages are characterized by lower dead OY ratios. PMID:24523247

White, Andrew A

2014-06-01

65

21 CFR 862.1455 - Lecithin/sphingomyelin ratio in amniotic fluid test system.  

Code of Federal Regulations, 2013 CFR

...DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CLINICAL CHEMISTRY AND CLINICAL TOXICOLOGY DEVICES Clinical Chemistry Test Systems § 862.1455 Lecithin/sphingomyelin ratio in amniotic fluid test...

2013-04-01

66

High contrast ratio and compact-sized prism for DLP projection system.  

PubMed

In this paper, a novel light separator with contrast ratio enhancement but maintaining the optical efficiency of the DLP projection system is proposed. The main capability of the novel light separator is to direct the uncontrolled light away from the image system. The working theorem for the novel light separator is derived as well. Uncontrolled light is kept away from the image system by a total internal reflection surface, thereby effectively improving the image quality. Compared with the conventional contrast ratio enhancement method, the FO:FO contrast ratio can be improved from 839:1 to 48250:1, the ANSI contrast ratio can be improved from 180:1 to 306:1, while the image system efficiency remains at 76.2%. PMID:25090516

Huang, Yung-Chih; Pan, Jui-Wen

2014-07-14

67

A trading-ratio system for trading water pollution discharge permits  

Microsoft Academic Search

The fact that water flows to the lowest level uni-directionally is a very specific and useful property of water. By utilizing this property, we design a trading-ratio system (TRS) of tradable discharge permits for water pollution control. Such a trading-ratio system has three main characteristics: (1) the zonal effluent cap is set by taking into account the water pollutant loads

Ming-Feng Hung; Daigee Shaw

2005-01-01

68

Performance of the Bowen ratio systems on a 22 deg slope  

NASA Technical Reports Server (NTRS)

The Bowen ratio energy balance technique was used to assess the energy fluxes on inclined surfaces during the First ISLSCP Field Experiment (FIFE). Since air flow over sloping surface may differ from that over flat terrain, it is important to examine whether Bowen ratio measurements taken on sloping surfaces are valid. In this study, the suitability of using the Bowen ratio technique on sloping surfaces was tested by examining the assumptions that the technique requires for valid measurements. This was accomplished by studying the variation of Bowen ratio measurements along a selected slope at the FIFE site. In September 1988, four Bowen ratio systems were set up in a line along the 22 degree north-facing slope with northerly air flow (wind went up the slope). In July of 1989, six Bowen ratio systems were similarly installed with southerly air flow (the wind went down slope). Results indicated that, at distances between 10 to 40 meters from the top of the slope, no temperature or vapor pressure gradient parallel to the slope was detected. Uniform Bowen ratio values were obtained on the slope, and thus the sensible or latent heat flux should be similar along the slope. This indicates that the assumptions for valid flux measurements are reasonably met at the slope. The Bowen ratio technique should give the best estimates of the energy fluxes on slopes similar to that in this study.

Nie, D.; Flitcroft, I.; Kanemasu, E. T.

1990-01-01

69

The Determination of Heat Capacity Ratios in a Simple Open System  

ERIC Educational Resources Information Center

A virtually closed system is treated as open and compared to known results. The classic experiment of Clement and Desormes provides the conceptual framework for this open system approach in determining the molar heat capacity ratios, lambda. This alternate view, extends the theoretical treatment beyond the first law of thermodynamics for closed…

Holden, Glen L.

2007-01-01

70

A system for estimating bowen ratio And evaporation from waste lagoons  

Technology Transfer Automated Retrieval System (TEKTRAN)

A low cost system was deployed above a swine waste lagoon to obtain estimates of Bowen ratios and characterize lagoon temperatures. The system consisted of humidity and temperature sensors and anemometers deployed above the lagoon, water temperature sensors, and a meteorological station located by t...

71

Peak-to-Average Power Ratio analysis in MIMO systems Basel Rihawi and Yves Louet  

E-print Network

1 Peak-to-Average Power Ratio analysis in MIMO systems Basel Rihawi and Yves Lou¨et IETR) systems based on Alamouti diversity scheme. This analysis is at both transmitter and re- ceiver sides Gaussian Noise (AWGN) influence on the Cumulative Distribution Function (CDF) of PAPR of a received signal

Boyer, Edmond

72

On the Planetary Orbital Period Ratio Distribution In Multiple Planet Systems  

NASA Astrophysics Data System (ADS)

Many multiple planet systems have been found by both radial velocity (RV) and transit surveys, such as the Kepler mission. Period ratio distribution of these planet candidates show that they do not prefer to be in or near Mean Motion Resonance (MMR). Nevertheless, there are small but significant excesses of candidate pairs both spaced slightly exterior to exact resonance, particular near the first order of MMR, such as 2:1 and 3:2. Here, we first review recent observational constraints on these multiple transiting systems and theoretical models, which attempt to understand their period ratio distributions. Then we identify a statistical effect based on an intrinsic asymmetry associated with MMR, and find it play an important role in shaping the period ratio distribution near MMR. Last but least, we also find such an intrinsic asymmetry is existing in asteroids of our solar system.

Xie, Ji-Wei

2014-04-01

73

Application of Taguchi methods to dual mixture ratio propulsion system optimization for SSTO vehicles  

NASA Technical Reports Server (NTRS)

The application of advanced technologies to future launch vehicle designs would allow the introduction of a rocket-powered, single-stage-to-orbit (SSTO) launch system early in the next century. For a selected SSTO concept, a dual mixture ratio, staged combustion cycle engine that employs a number of innovative technologies was selected as the baseline propulsion system. A series of parametric trade studies are presented to optimize both a dual mixture ratio engine and a single mixture ratio engine of similar design and technology level. The effect of varying lift-off thrust-to-weight ratio, engine mode transition Mach number, mixture ratios, area ratios, and chamber pressure values on overall vehicle weight is examined. The sensitivity of the advanced SSTO vehicle to variations in each of these parameters is presented, taking into account the interaction of each of the parameters with each other. This parametric optimization and sensitivity study employs a Taguchi design method. The Taguchi method is an efficient approach for determining near-optimum design parameters using orthogonal matrices from design of experiments (DOE) theory. Using orthogonal matrices significantly reduces the number of experimental configurations to be studied. The effectiveness and limitations of the Taguchi method for propulsion/vehicle optimization studies as compared to traditional single-variable parametric trade studies is also discussed.

Stanley, Douglas O.; Unal, Resit; Joyner, C. R.

1992-01-01

74

Development of a System to Measure Recrystallization Ratio of Plate Steel Using Laser-Based Ultrasonics  

NASA Astrophysics Data System (ADS)

In this study, a material property measurement system of plate steel using laser-based ultrasonics has been developed. The system consists of pulsed Nd:YAG laser for ultrasonic generation, CW single frequency laser and Fabry-Perot interferometer for ultrasonic detection. The system generates and detects shear waves and precisely calculates anisotropy parameter values of shear wave velocities of test samples. At first, the relationship between anisotropy parameter and recrystallization ratio was investigated in the laboratory experiments. Quenching the test samples just after the ultrasonic measurement, recrystallization ratio values were measured by the conventional microscopic method. According to the experimental results, the anisotropy parameter values showed a good correlation with actual recrystallization ratio values. To evaluate the applicability of the system to real steel production line, the system was installed in hot rolling pilot plant of plate steel. As the results, it was demonstrated that the system could measure the recrystallization ratio using the anisotropy parameter values of shear wave velocities, even in the environment of hot rolling pilot plant.

Nagata, Y.; Yamada, H.; Hamada, N.; Lim, C. S.; Yi, J. K.; Hong, S. T.; Choi, S. G.; Oh, K. J.

2007-03-01

75

Disturbance rejection performance analyses of closed loop control systems by reference to disturbance ratio.  

PubMed

This study investigates disturbance rejection capacity of closed loop control systems by means of reference to disturbance ratio (RDR). The RDR analysis calculates the ratio of reference signal energy to disturbance signal energy at the system output and provides a quantitative evaluation of disturbance rejection performance of control systems on the bases of communication channel limitations. Essentially, RDR provides a straightforward analytical method for the comparison and improvement of implicit disturbance rejection capacity of closed loop control systems. Theoretical analyses demonstrate us that RDR of the negative feedback closed loop control systems are determined by energy spectral density of controller transfer function. In this manner, authors derived design criteria for specifications of disturbance rejection performances of PID and fractional order PID (FOPID) controller structures. RDR spectra are calculated for investigation of frequency dependence of disturbance rejection capacity and spectral RDR analyses are carried out for PID and FOPID controllers. For the validation of theoretical results, simulation examples are presented. PMID:25311160

Alagoz, Baris Baykant; Deniz, Furkan Nur; Keles, Cemal; Tan, Nusret

2014-10-10

76

System for controlling the transmission ratio of an infinitely variable transmission  

SciTech Connect

This patent describes a system for controlling the transmission ratio of an infinitely variable transmission for a vehicle having a primary pulley having a hydraulically shiftable disc and a hydraulic cylinder for shifting the disc. A secondary pulley has a hydraulically shiftable disc and a hydraulic cylinder for operating the disc of the secondary pulley, a belt engaged with both pulleys, a hydraulic circuit having a pump for supplying pressurized oil, a transmission ratio control valve comprising a spool for shifting the disc of the primary pulley in a downshift direction and an upshift direction, respectively, and a pressure regulator valve for regulating the pressure of the oil, the system including shifting means for shifting the spool of the transmission ratio control valve in the upshift direction and in the downshift direction respectively in dependency on throttle position.

Miyawaki, M.

1987-04-21

77

Carbon\\/nitrogen ratio as a control element in aquaculture systems  

Microsoft Academic Search

Controlling the inorganic nitrogen by manipulating the carbon\\/nitrogen ratios is a potential control method for aquaculture systems. This approach seems to be a practical and inexpensive means of reducing the accumulation of inorganic nitrogen in the pond. Nitrogen control is induced by feeding bacteria with carbohydrates, and through the subsequent uptake of nitrogen from the water, by the synthesis of

Yoram Avnimelech

1999-01-01

78

Bionomic Exploitation of a Ratio-Dependent Predator-Prey System  

ERIC Educational Resources Information Center

The present article deals with the problem of combined harvesting of a Michaelis-Menten-type ratio-dependent predator-prey system. The problem of determining the optimal harvest policy is solved by invoking Pontryagin's Maximum Principle. Dynamic optimization of the harvest policy is studied by taking the combined harvest effort as a dynamic…

Maiti, Alakes; Patra, Bibek; Samanta, G. P.

2008-01-01

79

Constraints from Achondrites on the Initial 60Fe/56Fe Ratio of the Solar System  

NASA Astrophysics Data System (ADS)

We analyzed Fe-Ni systematics in eucrites and other types of achondrites, evidence of 60Fe presence was found in bulk eucrites and 60Fe/56Fe initial ratio in the early solar system was estimated, which is identical to the results from bulk angrite data.

Tang, H.; Dauphas, N.

2011-03-01

80

Peak-to-Average Power-Ratio Reduction Algorithms for OFDM Systems via Constellation Extension  

E-print Network

Peak-to-Average Power-Ratio Reduction Algorithms for OFDM Systems via Constellation Extension Y. J in computational complexity. In [5], a constellation extension technique for PAPR reduction was proposed where in a probabilistic framework [5]-[7]. New de-randomization algorithms are proposed based on a constellation extension

Lu, Wu-Sheng

81

New Peak-to-Average Power-Ratio Reduction Algorithms for OFDM Systems Using Constellation Extension  

E-print Network

New Peak-to-Average Power-Ratio Reduction Algorithms for OFDM Systems Using Constellation Extension is investigated in a probabilistic framework [5]-[7]. A new constellation extension technique for PAPR reduction constellation or by an extended point. In order to find the optimal representation of the OFDM signal, two de

Lu, Wu-Sheng

82

Inhibition to excitation ratio regulates visual system responses and behavior in vivo  

PubMed Central

The balance of inhibitory to excitatory (I/E) synaptic inputs is thought to control information processing and behavioral output of the central nervous system. We sought to test the effects of the decreased or increased I/E ratio on visual circuit function and visually guided behavior in Xenopus tadpoles. We selectively decreased inhibitory synaptic transmission in optic tectal neurons by knocking down the ?2 subunit of the GABAA receptors (GABAAR) using antisense morpholino oligonucleotides or by expressing a peptide corresponding to an intracellular loop of the ?2 subunit, called ICL, which interferes with anchoring GABAAR at synapses. Recordings of miniature inhibitory postsynaptic currents (mIPSCs) and miniature excitatory PSCs (mEPSCs) showed that these treatments decreased the frequency of mIPSCs compared with control tectal neurons without affecting mEPSC frequency, resulting in an ?50% decrease in the ratio of I/E synaptic input. ICL expression and ?2-subunit knockdown also decreased the ratio of optic nerve-evoked synaptic I/E responses. We recorded visually evoked responses from optic tectal neurons, in which the synaptic I/E ratio was decreased. Decreasing the synaptic I/E ratio in tectal neurons increased the variance of first spike latency in response to full-field visual stimulation, increased recurrent activity in the tectal circuit, enlarged spatial receptive fields, and lengthened the temporal integration window. We used the benzodiazepine, diazepam (DZ), to increase inhibitory synaptic activity. DZ increased optic nerve-evoked inhibitory transmission but did not affect evoked excitatory currents, resulting in an increase in the I/E ratio of ?30%. Increasing the I/E ratio with DZ decreased the variance of first spike latency, decreased spatial receptive field size, and lengthened temporal receptive fields. Sequential recordings of spikes and excitatory and inhibitory synaptic inputs to the same visual stimuli demonstrated that decreasing or increasing the I/E ratio disrupted input/output relations. We assessed the effect of an altered I/E ratio on a visually guided behavior that requires the optic tectum. Increasing and decreasing I/E in tectal neurons blocked the tectally mediated visual avoidance behavior. Because ICL expression, ?2-subunit knockdown, and DZ did not directly affect excitatory synaptic transmission, we interpret the results of our study as evidence that partially decreasing or increasing the ratio of I/E disrupts several measures of visual system information processing and visually guided behavior in an intact vertebrate. PMID:21795628

Shen, Wanhua; McKeown, Caroline R.; Demas, James A.

2011-01-01

83

Universal upper bound on the entropy-to-energy ratio for bounded systems  

Microsoft Academic Search

We present evidence for the existence of a universal upper bound of magnitude 2..pi..R\\/hc to the entropy-to-energy ratio S\\/E of an arbitrary system of effective radius R. For systems with negligible self-gravity, the bound follows from application of the second law of thermodynamics to a gedanken experiment involving a black hole. Direct statistical arguments are also discussed. A microcanonical approach

Jacob Bekenstein

1981-01-01

84

Multicanonical Determination of the Symbol Error Ratio of WDM Polarization Multiplexed QPSK Systems  

NASA Astrophysics Data System (ADS)

The multicanonical method is applied to the calculation of the symbol error ratio (SER) as a function of the optical signal to noise ratio (OSNR) at the receiver for a polarization multiplexed quadrature phase shift keying (PM-QPSK) wavelength division multiplexed (WDM) system. We improve upon previous calculations by including polarization mode dispersion (PMD) and subsequently verifying the numerical accuracy of our calculations. Our numerical studies demonstrate that acceptable accuracy can be achieved even when advancing the polarization through the fiber with relatively large propagation step lengths.

Soliman, George; Yevick, David

2014-12-01

85

Evaluation of denitrification-nitrification biofilter systems in treating wastewater with low carbon: nitrogen ratios.  

PubMed

A two-stage biological aerated/anoxic filter (BAF) system for denitrification-nitrification was developed to increase nitrogen removal in the treatment of municipal wastewater with low carbon:nitrogen (C/N) ratio [Formula: see text]. This system exhibited a high denitrification efficiency (67%), despite the low C/N ratio, and the ratio of reduced nitrate to consumed organic compounds was greater than the theoretical value due to the minimization of the conversion of organic carbon to biomass growth, the maintenance of low levels of dissolved oxygen in recycled water, and the maximization of use of organic carbon biosorbed inside biomass in the denitrification BAF. The maximum rate of nitrogen removal was achieved at a recycle ratio of 170%, and the headloss in two BAFs was maintained after a 24-h backwash. Biological nitrogen removal in a two-stage BAF system was possible in a short hydraulic retention time (1.2?h) because the maximum reaction rates of nitrifiers and denitrifiers in each column were achieved. PMID:25287910

Kim, Seungjin; Bae, Wookeun; Kim, Moonil; Kim, Jong-Oh; Chung, Jinwook

2015-04-01

86

System for controlling the transmission ratio of an infinitely variable transmission  

SciTech Connect

This patent describes a system for controlling a transmission ratio of an infinitely variable transmission for transmitting the power of an internal combustion engine. The infinitely variable transmission comprises a primary pulley having a hydraulically shiftable disc and a hydraulic cylinder for shifting the disc, a secondary pulley having a hydraulically shiftable disc and a hydraulic cylinder for shifting the disc of the secondary pulley. A belt is engaged with both pulleys, and a first hydraulic circuit has a pump for supplying pressurized oil. An axially movable transmission ratio control valve has a spool responsive to engine speed for controlling the pressurized oil so as to move the disc of the primary pulley to change the transmission ratio and a drain passage.

Nakamura, H.; Ohgami, M.

1987-05-12

87

System for controlling the transmission ratio in an infinitely variable transmission  

SciTech Connect

A control system is described for an infinitely variable transmission for a vehicle powered by an internal combustion engine, the transmission comprising a drive pulley having a hydraulically shiftable disc and a first hydraulic cylinder for shifting the disc. The pressure regulator valve has a second spool responsive to the transmission ratio for increasing line pressure of the hydraulic circuit with an increase of the transmission ratio. The improvement comprises: a plunger coaxial with the spool of the transmission ratio control valve and axially movable provided; a spring provided between the first spool and the plunger; first means for shifting the plunger in dependency on depression of an accelerator pedal of the vehicle, thereby via the spring shifting the first spool in opposition to the force dependent on the first signal; the manual selecting means for applying the line pressure to the actuator for releasing the actuator from the plunger; an actuator for shifting the plunger against the force dependent on the first signal; manual selecting means for operating the actuator for shifting the plunger against the force dependent on the first signal; second means responsive to the movement of the disc of the drive pulley from a predetermined transmission ratio in a transmission ratio increasing direction for disabling the actuator; and the manual selecting means for operating the actuator. When the actuator operates, the first spool is shifted at a predetermined engine speed, so that the transmission ratio begins to increase and the load on the spring is reduced after the predetermined transmission ratio by the operation of the second means.

Miyawaki, M.

1987-07-21

88

Influence of tire dynamics on slip ratio estimation of independent driving wheel system  

NASA Astrophysics Data System (ADS)

The independent driving wheel system, which is composed of in-wheel permanent magnet synchronous motor(I-PMSM) and tire, is more convenient to estimate the slip ratio because the rotary speed of the rotor can be accurately measured. However, the ring speed of the tire ring doesn't equal to the rotor speed considering the tire deformation. For this reason, a deformable tire and a detailed I-PMSM are modeled by using Matlab/Simulink. Moreover, the tire/road contact interface(a slippery road) is accurately described by the non-linear relaxation length-based model and the Magic Formula pragmatic model. Based on the relatively accurate model, the error of slip ratio estimated by the rotor rotary speed is analyzed in both time and frequency domains when a quarter car is started by the I-PMSM with a definite target torque input curve. In addition, the natural frequencies(NFs) of the driving wheel system with variable parameters are illustrated to present the relationship between the slip ratio estimation error and the NF. According to this relationship, a low-pass filter, whose cut-off frequency corresponds to the NF, is proposed to eliminate the error in the estimated slip ratio. The analysis, concerning the effect of the driving wheel parameters and road conditions on slip ratio estimation, shows that the peak estimation error can be reduced up to 75% when the LPF is adopted. The robustness and effectiveness of the LPF are therefore validated. This paper builds up the deformable tire model and the detailed I-PMSM models, and analyzes the effect of the driving wheel parameters and road conditions on slip ratio estimation.

Li, Jianqiu; Song, Ziyou; Wei, Yintao; Ouyang, Minggao

2014-10-01

89

Influence of tire dynamics on slip ratio estimation of independent driving wheel system  

NASA Astrophysics Data System (ADS)

The independent driving wheel system, which is composed of in-wheel permanent magnet synchronous motor(I-PMSM) and tire, is more convenient to estimate the slip ratio because the rotary speed of the rotor can be accurately measured. However, the ring speed of the tire ring doesn't equal to the rotor speed considering the tire deformation. For this reason, a deformable tire and a detailed I-PMSM are modeled by using Matlab/Simulink. Moreover, the tire/road contact interface(a slippery road) is accurately described by the non-linear relaxation length-based model and the Magic Formula pragmatic model. Based on the relatively accurate model, the error of slip ratio estimated by the rotor rotary speed is analyzed in both time and frequency domains when a quarter car is started by the I-PMSM with a definite target torque input curve. In addition, the natural frequencies(NFs) of the driving wheel system with variable parameters are illustrated to present the relationship between the slip ratio estimation error and the NF. According to this relationship, a low-pass filter, whose cut-off frequency corresponds to the NF, is proposed to eliminate the error in the estimated slip ratio. The analysis, concerning the effect of the driving wheel parameters and road conditions on slip ratio estimation, shows that the peak estimation error can be reduced up to 75% when the LPF is adopted. The robustness and effectiveness of the LPF are therefore validated. This paper builds up the deformable tire model and the detailed I-PMSM models, and analyzes the effect of the driving wheel parameters and road conditions on slip ratio estimation.

Li, Jianqiu; Song, Ziyou; Wei, Yintao; Ouyang, Minggao

2014-11-01

90

Air/fuel ratio monitoring system in ic engine using oxygen sensor  

SciTech Connect

An air/fuel ratio monitoring system in an IC engine, using an oxygen sensor of the concentration cell type which has a laminate comprising an inner electrode layer, a microscopically porous layer of oxygen ion conductive solid electrolyte and an outer electrode layer exposable to exhaust gas and which exhibits a sharp change in output voltage level in response to a change in the air/fuel ratio in the engine across a stoichiometric ratio. To ensure accurate monitoring of the air/fuel ratio even when the engine is operated under conditions which cause a large rise or fall in an average level of the output of the oxygen sensor, the monitoring system has a signal treatment means for producing a variable reference voltage, with which the sensor output is compared, by first adding a definite voltage to or subtracting a definite voltage from the output of the oxygen sensor depending on the result of comparison between the sensor output and the reference voltage and then smoothing the voltage resulting from the addition or subtraction of the definite voltage.

Kitahara, T.; Sone, K.; Uchida, M.

1985-01-22

91

The Minimum Mass Ratio for Contact Close Binary Systems of W Ursae Majoris-type  

NASA Astrophysics Data System (ADS)

Extreme mass ratio close binaries of W UMa-type represent an interesting class of objects in which ˜1M main-sequence star is in contact with a significantly less massive companion (M˜0.1M). Earlier theoretical investigations of these systems found that there is a minimum mass ratio q=M/M?0.085-0.095 (obtained for n=3 polytrope-fully radiative primary) above which these systems are stable. If the mass ratio is lower than minimum, a tidal instability develops (Darwin's instability). This instability, which is secular, growing on a viscous dissipation timescale, eventually forces the stars to merge into a single, rapidly rotating object (such as FK Com-type stars or blue stragglers), implying that such systems would not be observed. There appear to be, however, some W UMa-type binaries with empirically obtained q values below the theoretical limit for stability. The aim of this dissertation was to try to resolve the discrepancy between theory and observations by considering rotating polytropes. Other candidate systems for stellar mergers such as AM CVn-type stars have also been discussed in the dissertation.

Arbutina, Bojan

2009-09-01

92

Photometric Studies of Twelve Deep, Low-mass Ratio Overcontact Binary Systems  

NASA Astrophysics Data System (ADS)

The formations of the blue straggler stars and the FK Com-type stars are unsolved problems in stellar astrophysics. One of the possibilities for their formations is from the coalescence of W UMa-type overcontact binary systems. Therefore, deep (f > 50%), low-mass ratio (q < 0.25) overcontact binary stars are a very important source to understand the phenomena of Blue Straggler/FK Com-type stars. Recently, 12 W UMa-type binary stars, FG Hya, GR Vir, IK Per, TV Mus, CU Tau, V857 Her, V410 Aur, XY Boo, SX CrV, QX And, GSC 619-232, and AH Cnc, were investigated photometrically. Apart from TV Mus, XY boo, and GSC 619-232, new observations of the other 9 binaries were obtained. Complete light curves of the 10 systems, FG Hya, GR Vir, IK Per, TV Mus, CU Tau, V857 Her, GSC 619-232, V410 Aur, XY Boo, and AH Cnc, were analyzed with the 2003 version of the W-D code. It is shown that all of those systems are deep (f > 50%), low-mass ratio (q < 0.25) overcontact binary stars. We found that the system GSC 619-232 has the highest degree of overcontact (f = 93.4%). The derived photometric mass ratio of V857 Her, q = 0.0653, indicates that it is the lowest-mass ratio system among W UMa-type binaries. Of the 12 sample stars, long-term period changes of 11 systems were found. About 58% (seven) of the sample binaries show cyclic period oscillation. No cyclic period changes were discovered for the other 5 systems, which may be caused by the short observational time interval or by insufficient observations. Therefore, we think that all W UMa-type binary stars may contain cyclic period variations. By considering the long-term period changes (both increase and decrease) of those binary stars, we proposed two evolutionary scenarios evolving from deep, low-mass ratio overcontact binaries into Blue Straggler/FK Com-type stars.

Qian, Shengbang; Yang, Yuangui; Zhu, Liying; He, Jiajia; Yuan, Jingzhao

2006-08-01

93

First measurement of electron temperature from signal ratios in a double-pass Thomson scattering system  

SciTech Connect

This paper presents an experimental demonstration to determine electron temperature (T{sub e}) with unknown spectral sensitivity (transmissivity) in a Thomson scattering system. In this method, a double-pass scattering configuration is used and the scattered lights from each pass (with different scattering angles) are measured separately. T{sub e} can be determined from the ratio of the signal intensities without knowing a real chromatic dependence in the sensitivity. Note that the wavelength range for each spectral channel must be known. This method was applied to the TST-2 Thomson scattering system. As a result, T{sub e} measured from the ratio (T{sub e,r}) and T{sub e} measured from a standard method (T{sub e,s}) showed a good agreement with <|T{sub e,r}-T{sub e,s}|/T{sub e,s}>= 7.3%.

Tojo, H.; Itami, K.; Hatae, T. [Japan Atomic Energy Agency, 801-1 Mukoyama, Naka 311-0193 (Japan); Ejiri, A.; Yamaguchi, T.; Takase, Y. [Graduate School of Frontier Sciences, University of Tokyo, Kashiwa 277-8561 (Japan); Hiratsuka, J. [Graduate School of Science, University of Tokyo, Tokyo 113-0033 (Japan)

2012-02-15

94

Altering systemic acid-base balance through nutrition failed to change secondary sex ratio.  

PubMed

There is evidence that differences in either maternal blood pH or dietary mineral content can result in alterations in secondary sex ratio in mammals. Altering the proportions of certain dietary minerals is known to influence blood pH, offering a possible explanation for this effect of diet on secondary sex ratio. The present study was performed to investigate whether altering blood pH by manipulating the dietary cation-anion difference (DCAD) would alter secondary sex ratio. The DCAD is calculated (in mEq per 100 g dry matter) as the difference between metabolically strong cations (Na + K) and metabolically strong anions (Cl + S) in the diet. Three hundred female mice were randomly allocated to either a low or high DCAD ration for 3 weeks before coitus. Urine pH was monitored before beginning the experiment, as well as before and after the breeding period, as a proxy for blood pH. Mice on the low DCAD diet had a lower urine pH (mean (+/- s.d.) 6.0 +/- 0.1) than mice on the high DCAD diet (8.2 +/- 0.6), but DCAD did not affect the percentage of mice that became pregnant, the number of offspring per pregnant mouse or the sex ratio of the neonate group. These results suggest that blood pH alone does not alter sex ratio and that an altered systemic pH is not the reason for reported mineral-related variations in sex ratio. PMID:18076820

Roche, John R; Lee, Julia M

2007-01-01

95

Solving ratio-dependent predator-prey system with constant effort harvesting using Adomian decomposition method  

Microsoft Academic Search

In this paper, an algorithm based on Adomian’s decomposition method is developed to approximate the solution of the ratio-dependent predator–prey system with constant effort harvesting. The convergence of the decomposition series is enhanced using Padé approximation technique. The qualitative analysis of the model reveals that constant effort prey harvesting may contribute to mutual extinction as a possible outcome of predator–prey

Oluwole Daniel Makinde

2007-01-01

96

System for detecting the transmission ratio in an infinitely variable transmission  

SciTech Connect

An improved system is described for detecting the transmission ratio in an infinitely variable transmission for transmitting the power of an internal combustion engine. The transmission comprises primary pulley having a hydraulically shiftable disc and a hydraulic cylinder for shifting the disc and a secondary pulley having a hydraulically shiftable disc and a hydraulic cylinder for operating the disc of the secondary pulley. The transmission has a belt engaged with both pulleys, a hydraulic circuit having a pump for supplying oil, a transmission ratio control valve responsive to engine speed for controlling the oil and for shifting the disc of the primary pulley to change the transmission ratio, and a pressure regulator valve having a spool responsive to the transmission ratio for increasing the line pressure of the hydraulic circuit with an increase of the transmission ratio. A spring is held by a retainer for urging the spool in a direction. The improvement described here comprises: a sensor slidably mounted on a guide tube so as to move in parallel with the axial direction of the primary pulley; the sensor having a sensor head engaged with the disc of the primary pulley and an arm engaged with the retainer so as to shift the spool in dependency on the movement of the disc of the primary pulley to control the line pressure; and a lubricating system comprising passages provided in the guide tube and the sensor so as to communicate a part of the hydraulic circuit with an end opening of the passage of the sensor for lubricating contact surfaces of the head of the sensor and the disc of the primary pulley.

Sakai, Y.

1986-10-28

97

Characterization Of High-Stroke High-Aspect Ratio Micro Electro Mechanical Systems Deformable Mirrors For Adaptive Optics  

E-print Network

actuators  using  high  aspect  ratio  Innovative  Micro  Micro-Electro-Mechanical System (MEMS) X-beam actuatorsMicro-­?machines  Corporation  (BMC)  to  actuate  the   deformable  mirrors  actuators  

Bouchti, Mohamed Amine

2013-01-01

98

[Development of transient pyrometer based on multi-spectral radiation technology].  

PubMed

In modern dynamics system, the radiant temperature of the flame, which caused by the transient plasma stimulated by high-energy-level electromagnetism field, takes an important role in the description of the flying object's status as well as cauterization of the trajectory. Due to its extremely high temperature and transient process, the radiant temperature of the flame can hardly be measured through contracted ways, either static ways such as traditional pyrophotometer or CCD arrays. In the present paper, the authors bring forward a novel pyrophotometer based on classical theory of Planck's law (blackbody radiation law) and multi-channel spectrums radiation method. With this new type pyrophotometer, any spectrum can be selected out from the wavelength of 300 to 860 nm within 2 ns. Also, the application of high-definition diffraction grating and fibers can'ensure the accuracy of selected spectrum. The results through a serial of experiments by using this theory as well as high-speed photodetector indicate that this method is valid and accurate for the measurement of the object's surface's radiant temperature. PMID:21284205

Zhai, Yang; Shen, Hua; Zhu, Ri-hong; Ma, Suo-dong; Li, Jian-xin; Chen, Lei; Gu, Jin-liang

2010-11-01

99

Carrier - Interference ratios for frequency sharing between satellite systems transmitting frequency modulated and digital television signals  

NASA Technical Reports Server (NTRS)

As the data rates required for digitally encoded television are reduced, satellite systems employing the transmission of digitally encoded television will become attractive. It is likely that television transmitted in this format will be adjacent to or in the same frequency band as television transmissions in other modulation formats, so a knowledge of carrier to interference power ratios as a function of assessed picture quality will be required for frequency sharing between these different modulation formats. This paper presents the results of subjective and quantitative tests describing the results of interference to a particular digital television system from a frequency modulated (FM) television system, and for interference to an FM television system from a digital television system.

Barnes, S. P.

1979-01-01

100

The Minimum Mass Ratio for Contact Close Binary Systems of W Ursae Majoris-Type  

NASA Astrophysics Data System (ADS)

The main research topic of this dissertation are extreme mass ratio contact close binary systems, q ? 0.1, of W Ursae Majoris (W UMa) type. These close binaries (CBs) represent an interesting class of objects in which "normal", approximately one solar mass main-sequence star is in contact with a significantly less massive companion, M_2 ˜ 0.1 M_?. Earlier theoretical investigations of these systems found that there is a minimum mass ratio q_{min} = M_2/M_1 = 0.085 - 0.095 (obtained for n = 3 polytrope - fully radiative primary) above which these CBs are stable and could be observed. If the mass ratio is lower than q_{min}, or, equivalently, if orbital angular momentum is only about three times larger than the spin angular momentum of a massive primary, a tidal instability develops (Darwin's instability) forcing eventually the stars to merge into a single, rapidly rotating object (such as FK Com-type stars or blue stragglers). However, there appear to be some W UMa-type CBs with empirically obtained values for the mass ratio below the theoretical limit for stability. The aim of this dissertation is to try to resolve the discrepancy between theory and observations by considering rotating polytropes. By including in theory the effects of higher central condensation due to rotation we were able to reduce qmin to the new theoretical value q_{min} = 0.070-0.074, for the overcontact degree f = 0 - 1, which is more consistent with the observed population. Other candidate systems for stellar mergers such as AM CVn-type stars have also been discussed in the dissertation.

Arbutina, B.

2012-12-01

101

System for feedback control of air-fuel mixing ratio in intake system of internal combustion engine  

SciTech Connect

A feedback control system using an oxygen-sensitive air/fuel ratio sensor which is disposed in induction passage for an ic engine downstream of a fuel supply device with the provision of an ignition means to burn a fractional portion of an air-fuel mixture in the induction passage such that the oxygen-sensitive sensor is exposed to a resultant combustion gas. The sensor is of the concentration cell type having a layer of solid electrolyte such as zirconia provided with two electrode layers, and constant dc current is supplied to this sensor to cause migration of oxygen ions through the solid electrolyte layer, whereby this sensor exhibits a slope output characteristic and can detect air/fuel ratios either above or below a stoichiometric ratio or exhibits an on-off characteristic and can detect the stoichiometric ratio depending on the intensity and flow direction of the current. Owing to reduced overall length of the closed-loop, this control system can accomplish correction of a deviated mixing ratio in a shortened period of time.

Masaki, K.; Sone, K.; Takase, S.

1982-11-23

102

Binary star statistics - The mass ratio distribution for very wide systems  

NASA Astrophysics Data System (ADS)

Published observational data on a common-proper-motion sample (CPMS) of 326 pairs of AGK 3 stars (Halbwachs, 1986) with proper motion greater than 50 marcsec/yr and separation/proper-motion ratios less than 1000 yr are analyzed statistically to determine the frequency distribution of mass ratios (q = M2/M1). The results are presented in tables and graphs and compared with those for a sample of 798 visual binaries (VBs) studied by Worley and Heintz (1983). Both samples are found to have distributions with a peak at q = about 1, but this tendency is more pronounced in the VBs than in the CPMS. The q distribution of the VB sample, unlike that of the CPMS, cannot be explained by assuming that it is a random sample of normal initial mass functions; from this it is inferred that a binary formation mechanism which favors systems with q = about 1 may be involved.

Trimble, V.

103

The minimum mass ratio of W UMa-type binary systems  

NASA Astrophysics Data System (ADS)

When the total angular momentum of a binary system Jtot = Jorb + Jspin is at a certain critical (minimum) value, a tidal instability occurs which eventually forces the stars to merge into a single, rapidly rotating object. The instability occurs when Jorb = 3Jspin, which in the case of contact binaries corresponds to a minimum mass ratio qmin ~ 0.071-0.078. The minimum mass ratio is obtained under the assumption that stellar radii are fixed and independent. This is not the case with contact binaries where, according to the Roche model, we have R2 = R2(R1, a, q). By finding a new criterion for contact binaries, which arises from dJtot = 0, and assuming k21 ? k22 for the component's dimensionless gyration radii, a theoretical lower limit qmin = 0.094-0.109 for overcontact degree f = 0-1 is obtained.

Arbutina, B.

2007-06-01

104

Combinatorial screening of photoelectrocatalytic system with high signal/noise ratio.  

PubMed

Solar energy is the most abundant nature resource and plays important roles in the sustainable developments of energy and environment. Scanning photoelectrochemical microscopy provides a high-throughput screening method by introducing the combinatorial technique to prepare the substrate with photoelectrochemical catalyst array. However, the signal/noise (S/N) ratio suffers from the background current of indium-tin oxide or fluorine-doped tin oxide itself, including a transient charge-discharge current of electric double layer and a steady-state photocatalytic current. Here we adopt a facile microfabrication method to isolate the substrate area other than the catalyst array from not only the electrolyte solution but also the light illumination. Consequently, the imaging quality has been promoted dramatically due to suppressed background current. This method provides a high S/N ratio screening method, which will be valuable for the high-throughput optimization of the photoelectrocatalytic system. PMID:25417799

Yuan, Ding; Xiao, Lina; Jia, Jingchun; Zhang, Jie; Han, Lianhuan; Li, Pei; Mao, Bing-Wei; Zhan, Dongping

2014-12-16

105

Estimation of Theaflavins (TF) and Thearubigins (TR) Ratio in Black Tea Liquor Using Electronic Vision System  

NASA Astrophysics Data System (ADS)

Quality of black tea is generally assessed using organoleptic tests by professional tea tasters. They determine the quality of black tea based on its appearance (in dry condition and during liquor formation), aroma and taste. Variation in the above parameters is actually contributed by a number of chemical compounds like, Theaflavins (TF), Thearubigins (TR), Caffeine, Linalool, Geraniol etc. Among the above, TF and TR are the most important chemical compounds, which actually contribute to the formation of taste, colour and brightness in tea liquor. Estimation of TF and TR in black tea is generally done using a spectrophotometer instrument. But, the analysis technique undergoes a rigorous and time consuming effort for sample preparation; also the operation of costly spectrophotometer requires expert manpower. To overcome above problems an Electronic Vision System based on digital image processing technique has been developed. The system is faster, low cost, repeatable and can estimate the amount of TF and TR ratio for black tea liquor with accuracy. The data analysis is done using Principal Component Analysis (PCA), Multiple Linear Regression (MLR) and Multiple Discriminate Analysis (MDA). A correlation has been established between colour of tea liquor images and TF, TR ratio. This paper describes the newly developed E-Vision system, experimental methods, data analysis algorithms and finally, the performance of the E-Vision System as compared to the results of traditional spectrophotometer.

Akuli, Amitava; Pal, Abhra; Ghosh, Arunangshu; Bhattacharyya, Nabarun; Bandhopadhyya, Rajib; Tamuly, Pradip; Gogoi, Nagen

2011-09-01

106

Component video signal-to-noise ratio analysis of FM and AM television systems  

NASA Astrophysics Data System (ADS)

The objective signal-to-noise performance of component color video signals is analyzed in this paper for FM and AM-VSB video transmission systems. In the analysis, the effect of splitting the composite video signal into its components, by subcarrier demodulation and color decoding, is taken into consideration. The effect of non linearity of the display is also included in the analysis. An expression for objective component signal-to-noise ratio is derived for both the transmission system. A relationship between the conventional composite video SNR and the component video SNR is established. Effective noise transfer, between the input and various stages of video signal processing, is discussed in detail. Noise spectral density analysis, for fully saturated primary colors, is evaluated quantitatively for a PAL-I video system. Finally, SNR performance of various hues at constant luminance is evaluated, and the results obtained are compared with the subjective noise visibility tests first carried out in 1957.

Selvan, B.; Green, R. J.

1994-02-01

107

Spatio-temporal patterns of C : N : P ratios in the northern Benguela upwelling system  

NASA Astrophysics Data System (ADS)

On a global scale the ratio of fixed nitrogen (N) and phosphate (P) is characterized by a deficit of N with regard to the classical Redfield ratio of N : P = 16 : 1 reflecting the impact of N loss occurring in the oceanic oxygen minimum zones. The northern Benguela upwelling system (NBUS) is known for losses of N and the accumulation of P in sub- and anoxic bottom waters and sediments of the Namibian shelf resulting in low N : P ratios in the water column. To study the impact of the N : P anomalies on the regional carbon cycle and their consequences for the export of nutrients from the NBUS into the oligotrophic subtropical gyre of the South Atlantic, we measured dissolved inorganic carbon (CT), total alkalinity (AT), oxygen (O2) and nutrient concentrations in February 2011. The results indicate increased P concentrations over the Namibian shelf due to P efflux from sediments resulting in a C : N : P : -O2 ratio of 106 : 16 : 1.6 : 138. N reduction further increase C : N and reduce N : P ratios in those regions where O2 concentrations in bottom waters are < 20 ?mol kg-1. However, off the shelf along the continental margin, the mean C : N : P : -O2 ratio is again close to the Redfield stoichiometry. Additional nutrient data measured during two cruises in 2008 and 2009 imply that the amount of excess P, which is created in the bottom waters on the shelf, and its export into the subtropical gyre after upwelling varies through time. The results further reveal an inter-annual variability of excess N within the South Atlantic Central Water (SACW) that flows from the north into the NBUS, with highest N values observed in 2008. It is postulated that the N excess in SACW occurred due to the impact of remineralized organic matter produced by N2 fixation and that the magnitude of excess P formation and its export is governed by inputs of excess N along with SACW flowing into the NBUS. Factors controlling N2 fixation north of the BUS need to be addressed in future studies to better understand the role of the NBUS as a P source and N sink in the coupled C : N : P cycles.

Flohr, A.; van der Plas, A. K.; Emeis, K.-C.; Mohrholz, V.; Rixen, T.

2014-02-01

108

New Progress on High Fill-Out, Extreme Mass Ratio Overcontact Binary Systems  

NASA Astrophysics Data System (ADS)

High Fill-Out, Extreme Mass Ratio Overcontact Binary (HFEMOB) are a very important source to understand the structure and evolution of the late-type short-period close binary stars, because they are at the late evolutionary stage of these systems. Recently, the detail photometric studies of fifteen such HFEMOBs, including GR Vir, IK Per, FG Hya, TV Mus, CU Tau, V857 Her, GSC619-232, V410 Aur, XY Boo, AH Cnc, QX and, EM Psc, V345 Gem, XY LMi and V1191 Cyg were published. In the present paper, we summarize these results and give some new observations of some HFEMOB candidates.

He, J.; Qian, S.; Soonthornthum, B.

2011-12-01

109

System for controlling the transmission ratio of an infinitely variable transmission  

SciTech Connect

This patent describes a system for controlling the transmission ratio of an infinitely variable transmission for an engine mounted on a vehicle, the engine having a throttle valve and an electromagnetic clutch having a coil for transmitting the power of the engine to the transmission. The transmission comprises a primary pulley having a hydraulically shiftable disc and a hydraulic cylinder for operating the disc, a secondary pulley having a hydraulically shiftable disc and a hydraulic cylinder for operating the disc of the secondary pulley, and a belt engaged with both pulleys.

Ohgami, M.

1987-07-21

110

Asthma drug ratios and exacerbations: claims data from universal health coverage systems.  

PubMed

In claims data, controller-to-total asthma drug ratios may reflect adequacy of disease management. We verified whether asthma patients with high ratios (? 50%) experienced fewer asthma-related outcomes. Two ratios were studied: that of the inhaled corticosteroids to total asthma drug (ICS/R03) and that of the inhaled corticosteroids plus leukotriene antagonist receptors-to-total asthma drug (ICS+LTRA/R03). Patients aged 13-40 years, with ? 3 respiratory drugs dispensed prescriptions in 2005 were selected from the French national claims data. After excluding null ratios, two groups were defined according to ratio values in 2007: low-ratio group (0% < ratio < 50%) and high-ratio group (ratio ? 50%). For both ratios, asthma-related outcomes and medical-resource utilisation were compared between groups. Of 2162 patients (mean age 27 years and 52% female), patients with non-null ratios were 81% and 85% for ICS/R03 and ICS+LTRA/R03 ratios, respectively. Patients with high ratios were less likely to receive oral corticosteroids than those in the low-ratio group (relative risk 0.79, 95% CI 0.72-0.88, and 0.80, 95% CI 0.72-0.88, for ICS/R03 and ICS+LTRA/R03, respectively). High ratio groups also presented fewer asthma-related hospitalisations. Significant negative correlations were also observed for both ratios, when studied quantitatively, according to patients' dispensed level of oral corticosteroids in 2007. In claims data, both ICS/R03 and ICS+LTRA/R03 ? 50% were related to fewer asthma-related outcomes. Ratios should be explored to identify asthma patients at risk of exacerbations. Low ratios can be considered as risk factors of exacerbation whatever the underlying cause. PMID:24789951

Laforest, Laurent; Licaj, Idlir; Devouassoux, Gilles; Chatte, Gérard; Martin, Jennifer; Van Ganse, Eric

2014-05-01

111

A study on the optimal hydraulic loading rate and plant ratios in recirculation aquaponic system.  

PubMed

The growths of the African catfish (Clarias gariepinus) and water spinach (Ipomoea aquatica) were evaluated in recirculation aquaponic system (RAS). Fish production performance, plant growth and nutrient removal were measured and their dependence on hydraulic loading rate (HLR) was assessed. Fish production did not differ significantly between hydraulic loading rates. In contrast to the fish production, the water spinach yield was significantly higher in the lower hydraulic loading rate. Fish production, plant growth and percentage nutrient removal were highest at hydraulic loading rate of 1.28 m/day. The ratio of fish to plant production has been calculated to balance nutrient generation from fish with nutrient removal by plants and the optimum ratio was 15-42 gram of fish feed/m(2) of plant growing area. Each unit in RAS was evaluated in terms of oxygen demand. Using specified feeding regime, mass balance equations were applied to quantify the waste discharges from rearing tanks and treatment units. The waste discharged was found to be strongly dependent on hydraulic loading rate. PMID:19819130

Endut, Azizah; Jusoh, A; Ali, N; Wan Nik, W B; Hassan, A

2010-03-01

112

A multi-wavelength streak-optical-pyrometer for warm-dense matter experiments at NDCX-I and NDCX-II  

NASA Astrophysics Data System (ADS)

We report on a multi-wavelength streak-optical-pyrometer (SOP) developed the for warm-dense-matter (WDM) experiments at the existing NDCX-I facility and the NDCX-II facility currently being commissioned at LBNL. The SOP served as the primary temperature diagnostic in the recent NDCX-I experiments, in which an intense K+ beam was used to heat different metal samples into WDM states. The SOP consists of a spectral grating (visible and near-infrared spectral range) and a fast, high-dynamic-range optical streak camera. The instrument is calibrated absolutely with a NIST-traceable tungsten ribbon lamp and can itself be considered as an absolutely calibrated, time-resolving spectrometer. The sample temperature is determined from fitting the recorded thermal spectrum into the Planck formula multiplied by a model of emissivity.

Ni, P. A.; Bieniosek, F. M.; Henestroza, E.; Lidia, S. M.

2014-01-01

113

Spatiotemporal complexity of a ratio-dependent predator-prey system.  

PubMed

In this paper, we investigate the emergence of a ratio-dependent predator-prey system with Michaelis-Menten-type functional response and reaction diffusion. We obtain the conditions of Hopf, Turing, and wave bifurcation in a spatial domain. Furthermore, we present a theoretical analysis of evolutionary processes that involves organisms distribution and their interaction of spatially distributed population with local diffusion. The results of numerical simulations reveal that the typical dynamics of population density variation is the formation of isolated groups, i.e., stripelike or spotted or coexistence of both. Our study shows that the spatially extended model has not only more complex dynamic patterns in the space, but also chaos and spiral waves. It may help us better understand the dynamics of an aquatic community in a real marine environment. PMID:17677104

Wang, Weiming; Liu, Quan-Xing; Jin, Zhen

2007-05-01

114

Deep, Low Mass Ratio Overcontact Binary Systems. III. CU Tauri and TV Muscae  

NASA Astrophysics Data System (ADS)

New CCD photometric light curves in the B and V bands of the neglected W UMa-type eclipsing variable star CU Tauri are presented. The O'Connell effect in the V light curve obtained in 2001 by Yang and Liu was about ?V=+0.015, but it vanished in our 2004 observations. The variations in the levels of both minima were seen. Our two epochs of light minimum and others compiled from the literature were used for the period study. It is shown that the types of some eclipse times were incorrect and the values of the period obtained by previous investigators were aliases that prevented formation of a plausible O-C curve. A new linear ephemeris was derived, and it is discovered that the orbital period of CU Tau shows a continuous decrease at a rate of dP/dt=-1.81×10-6 days yr-1. The present symmetric light curves were solved with the 2003 version of the Wilson-Devinney (W-D) code. Both our solutions and those derived by Yang and Liu reveal that CU Tau is a deep (f=50.1%+/-3.2%), low mass ratio (q=0.1770+/-0.0017) overcontact binary system. Meanwhile, the photoelectric light curves in the B, V, R, and I bands of TV Muscae published by Hilditch and coworkers were reanalyzed with the 2003 version of the W-D code. It is shown that the low mass ratio binary turns out to be a deep overcontact system with f=74.3%+/-11.3%. A period analysis with all collected times of light minimum revealed a combination of a long-term period decrease (dP/dt=-2.16×10-7 days yr-1) and a possible cyclic change with a period of 29.1 yr. The rapid long-term period decreases of both systems can be explained as a combination of the mass transfer from the more massive component to the less massive one and the angular momentum loss due to mass outflow from the L2 point. In that way, the overcontact degrees of the two systems will become deeper as their periods decrease, and finally they will evolve into a single rapid-rotation star. However, for CU Tau, the rate of the secular period decrease is very large when compared with the other systems of the same type. This suggests that the long-term period decrease may be part of a long-period periodic change, which we need more data to check.

Qian, S.-B.; Yang, Y.-G.; Soonthornthum, B.; Zhu, L.-Y.; He, J.-J.; Yuan, J.-Z.

2005-07-01

115

Reliability analysis of a passive cooling system using a response surface with an application to the Flexible Conversion Ratio Reactor  

E-print Network

A comprehensive risk-informed methodology for passive safety system design and performance assessment is presented and demonstrated on the Flexible Conversion Ratio Reactor (FCRR). First, the methodology provides a framework ...

Fong, Christopher J. (Christopher Joseph)

2008-01-01

116

Signal to noise ratio of energy selective x-ray photon counting systems with pileup  

PubMed Central

Purpose: To derive fundamental limits on the effect of pulse pileup and quantum noise in photon counting detectors on the signal to noise ratio (SNR) and noise variance of energy selective x-ray imaging systems. Methods: An idealized model of the response of counting detectors to pulse pileup is used. The model assumes a nonparalyzable response and delta function pulse shape. The model is used to derive analytical formulas for the noise and energy spectrum of the recorded photons with pulse pileup. These formulas are first verified with a Monte Carlo simulation. They are then used with a method introduced in a previous paper [R. E. Alvarez, “Near optimal energy selective x-ray imaging system performance with simple detectors,” Med. Phys. 37, 822–841 (2010)] to compare the signal to noise ratio with pileup to the ideal SNR with perfect energy resolution. Detectors studied include photon counting detectors with pulse height analysis (PHA), detectors that simultaneously measure the number of photons and the integrated energy (NQ detector), and conventional energy integrating and photon counting detectors. The increase in the A-vector variance with dead time is also computed and compared to the Monte Carlo results. A formula for the covariance of the NQ detector is developed. The validity of the constant covariance approximation to the Cramèr–Rao lower bound (CRLB) for larger counts is tested. Results: The SNR becomes smaller than the conventional energy integrating detector (Q) SNR for 0.52, 0.65, and 0.78 expected number photons per dead time for counting (N), two, and four bin PHA detectors, respectively. The NQ detector SNR is always larger than the N and Q SNR but only marginally so for larger dead times. Its noise variance increases by a factor of approximately 3 and 5 for the A1 and A2 components as the dead time parameter increases from 0 to 0.8 photons per dead time. With four bin PHA data, the increase in variance is approximately 2 and 4 times. The constant covariance approximation to the CRLB is valid for larger counts such as those used in medical imaging. Conclusions: The SNR decreases rapidly as dead time increases. This decrease places stringent limits on allowable dead times with the high count rates required for medical imaging systems. The probability distribution of the idealized data with pileup is shown to be accurately described as a multivariate normal for expected counts greater than those typically utilized in medical imaging systems. The constant covariance approximation to the CRLB is also shown to be valid in this case. A new formula for the covariance of the NQ detector with pileup is derived and validated. PMID:25370642

Alvarez, Robert E.

2014-01-01

117

The differential Howland current source with high signal to noise ratio for bioimpedance measurement system  

NASA Astrophysics Data System (ADS)

The stability and signal to noise ratio (SNR) of the current source circuit are the important factors contributing to enhance the accuracy and sensitivity in bioimpedance measurement system. In this paper we propose a new differential Howland topology current source and evaluate its output characters by simulation and actual measurement. The results include (1) the output current and impedance in high frequencies are stabilized after compensation methods. And the stability of output current in the differential current source circuit (DCSC) is 0.2%. (2) The output impedance of two current circuits below the frequency of 200 KHz is above 1 M?, and below 1 MHz the output impedance can arrive to 200 K?. Then in total the output impedance of the DCSC is higher than that of the Howland current source circuit (HCSC). (3) The SNR of the DCSC are 85.64 dB and 65 dB in the simulation and actual measurement with 10 KHz, which illustrates that the DCSC effectively eliminates the common mode interference. (4) The maximum load in the DCSC is twice as much as that of the HCSC. Lastly a two-dimensional phantom electrical impedance tomography is well reconstructed with the proposed HCSC. Therefore, the measured performance shows that the DCSC can significantly improve the output impedance, the stability, the maximum load, and the SNR of the measurement system.

Liu, Jinzhen; Qiao, Xiaoyan; Wang, Mengjun; Zhang, Weibo; Li, Gang; Lin, Ling

2014-05-01

118

Two new systems with enhanced UV line flux ratios as indication of the evolution of cataclysmic variables  

NASA Astrophysics Data System (ADS)

We present ultraviolet spectra of 62 cataclysmic variables observed with Hubble Space Telescope Space Telescope Imaging Spectrograph & Faint Object Spectrograph (HST STIS FOS) to diagnose cataclysmic variables with enhanced NV/C IV line flux ratios. We concentrated on calculating the line flux ratios of the above mentioned sample. We found that a number of cataclysmic variables reveal enhanced NV/C IV line flux ratios in agreement with the previous studies ( de Martino and Gänsicke, 2009; Gänsicke et al., 2003). Also we found that two new systems (U SCO, V1974 CYG) reveal enhanced NV/C IV line flux ratios. Such anomalous line flux ratios confirmed that these CVs went through a phase of thermal timescale mass transfer (TTSMT) and now accrete CNO processed material from a companion stripped of its external layers ( Gänsicke et al., 2003; Gänsicke, 2004; de Martino and Gänsicke, 2009).

Sanad, M. R.

2011-01-01

119

Mobile lidar system for measurement of water vapor mixing ratio and ozone number density  

NASA Technical Reports Server (NTRS)

The Water Vapor Lidar was modified and extended to make differential absorption measurements of ozone. Water vapor measurements make use of a weak molecular scattering process known as Raman scattering. It is characterized by a shift in wavelength of the scattered beam of light relative to the incident one. Some of the energy of the incident photon is converted to vibrational or rotational energy within the molecule leaving the scattered photon shifted to a slightly longer wavelength. When performing water vapor measurements, profiles are acquired of water vapor mixing ratio from near the ground to beyond 7 km every 2 minutes. By forming a color composite image of the individual profiles, the spatial and temporal evolution of water vapor is visible with vertical resolution of 75 to 150m and temporal resolution of 2 minutes. The ozone lidar is intended for use as a cross calibration facility for other stationary ozone lidar systems. The ozone measurement employs the technique known as differential absorption. The backscattered laser radiation from two different wavelengths is measured. Successful measurements of 308 nm returns were made from 80 km with an averaging period of 6 hours. Using these data and a standard atmosphere density curve, an ozone number density profile was made which agrees very well with the standard ozone curve between 20 and 40 km.

Whiteman, D.

1988-01-01

120

A synthetic sex ratio distortion system for the control of the human malaria mosquito  

PubMed Central

It has been theorized that inducing extreme reproductive sex ratios could be a method to suppress or eliminate pest populations. Limited knowledge about the genetic makeup and mode of action of naturally occurring sex distorters and the prevalence of co-evolving suppressors has hampered their use for control. Here we generate a synthetic sex distortion system by exploiting the specificity of the homing endonuclease I-PpoI, which is able to selectively cleave ribosomal gene sequences of the malaria vector Anopheles gambiae that are located exclusively on the mosquito’s X chromosome. We combine structure-based protein engineering and molecular genetics to restrict the activity of the potentially toxic endonuclease to spermatogenesis. Shredding of the paternal X chromosome prevents it from being transmitted to the next generation, resulting in fully fertile mosquito strains that produce >95% male offspring. We demonstrate that distorter male mosquitoes can efficiently suppress caged wild-type mosquito populations, providing the foundation for a new class of genetic vector control strategies. PMID:24915045

Galizi, Roberto; Doyle, Lindsey A.; Menichelli, Miriam; Bernardini, Federica; Deredec, Anne; Burt, Austin; Stoddard, Barry L.; Windbichler, Nikolai; Crisanti, Andrea

2014-01-01

121

Group Ratio Round-Robin: O(1) Proportional Share Scheduling for Uniprocessor and Multiprocessor Systems  

E-print Network

Group Ratio Round-Robin: O(1) Proportional Share Scheduling for Uniprocessor and Multiprocessor of Computer Science Columbia University Technical Report CUCS-028-04 July 2004Abstract Proportional share. We present Group Ratio Round-Robin (GR3 ), the first proportional share scheduler that combines accu

Yang, Junfeng

122

Improving Compression Ratio, Area Overhead, and Test Application Time for System-on-a-Chip Test Data Compression\\/Decompression  

Microsoft Academic Search

This paper proposes a new test data compression\\/decompression method for systems-on-a-chip. Themethod is based on analyzing the factors that influencetest parameters: compression ratio, area overhead and testapplication time. To improve compression ratio, the newmethod is based on a Variable-length Input Huffman Coding(VIHC), which fully exploits the type and length of the patterns,as well as a novel mapping and reordering algorithmproposed

Paul Theo Gonciari; Bashir M. Al-Hashimi; Nicola Nicolici

2002-01-01

123

Design of passive decay heat removal system for the lead cooled flexible conversion ratio fast reactor  

E-print Network

The lead-cooled flexible conversion ratio fast reactor shows many benefits over other fast-reactor designs; however, the higher power rating and denser primary coolant present difficulties for the design of a passive decay ...

Whitman, Joshua (Joshua J.)

2007-01-01

124

Evaluation of an automated safety surveillance system using risk adjusted sequential probability ratio testing  

PubMed Central

Background Automated adverse outcome surveillance tools and methods have potential utility in quality improvement and medical product surveillance activities. Their use for assessing hospital performance on the basis of patient outcomes has received little attention. We compared risk-adjusted sequential probability ratio testing (RA-SPRT) implemented in an automated tool to Massachusetts public reports of 30-day mortality after isolated coronary artery bypass graft surgery. Methods A total of 23,020 isolated adult coronary artery bypass surgery admissions performed in Massachusetts hospitals between January 1, 2002 and September 30, 2007 were retrospectively re-evaluated. The RA-SPRT method was implemented within an automated surveillance tool to identify hospital outliers in yearly increments. We used an overall type I error rate of 0.05, an overall type II error rate of 0.10, and a threshold that signaled if the odds of dying 30-days after surgery was at least twice than expected. Annual hospital outlier status, based on the state-reported classification, was considered the gold standard. An event was defined as at least one occurrence of a higher-than-expected hospital mortality rate during a given year. Results We examined a total of 83 hospital-year observations. The RA-SPRT method alerted 6 events among three hospitals for 30-day mortality compared with 5 events among two hospitals using the state public reports, yielding a sensitivity of 100% (5/5) and specificity of 98.8% (79/80). Conclusions The automated RA-SPRT method performed well, detecting all of the true institutional outliers with a small false positive alerting rate. Such a system could provide confidential automated notification to local institutions in advance of public reporting providing opportunities for earlier quality improvement interventions. PMID:22168892

2011-01-01

125

Chondrites - Initial strontium-87/strontium-86 ratios and the early history of the solar system.  

NASA Technical Reports Server (NTRS)

A sodium-poor, calcium-rich inclusion in the carbonaceous chondrite Allende had a Sr-87/Sr-86 ratio at the time of its formation of 0.69880, as low a value as that found in any other meteorite. The higher Sr-87/Sr-86 ratios found in ordinary chondrites indicate that their formation or isotopic equilibration occurred tens of millions of years later.

Wetherill, G. W.; Mark, R.; Lee-Hu, C.

1973-01-01

126

Association Mining System for Financial Ratios and Stock Prices in China and Hong Kong Stock Exchange  

Microsoft Academic Search

The focus of this paper is to extract association rules for financial ratios against stock price change. A data mining application\\u000a for association rules on China and Hong Kong Stock Market has been built and to be accessed through the WEB. Preprocessing\\u000a has been done to convert the data on financial report to financial ratios to allow for direct comparison.

Man-chung Chan; H. C. Leung; W. D. Luo

2005-01-01

127

Lamp mapping technique for independent determination of the water vapor mixing ratio calibration factor for a Raman lidar system.  

PubMed

We have investigated a technique that allows for the independent determination of the water vapor mixing ratio calibration factor for a Raman lidar system. This technique utilizes a procedure whereby a light source of known spectral characteristics is scanned across the aperture of the lidar system's telescope and the overall optical efficiency of the system is determined. Direct analysis of the temperature-dependent differential scattering cross sections for vibration and vibration-rotation transitions (convolved with narrowband filters) along with the measured efficiency of the system, leads to a theoretical determination of the water vapor mixing ratio calibration factor. A calibration factor was also obtained experimentally from lidar measurements and radiosonde data. A comparison of the theoretical and experimentally determined values agrees within 5%. We report on the sensitivity of the water vapor mixing ratio calibration factor to uncertainties in parameters that characterize the narrowband transmission filters, the temperature-dependent differential scattering cross section, and the variability of the system efficiency ratios as the lamp is scanned across the aperture of the telescope used in the Howard University Raman Lidar system. PMID:21833140

Venable, Demetrius D; Whiteman, David N; Calhoun, Monique N; Dirisu, Afusat O; Connell, Rasheen M; Landulfo, Eduardo

2011-08-10

128

Implications for the False-positive Rate in Kepler Planet Systems from Transit Duration Ratios  

NASA Astrophysics Data System (ADS)

Confirming transiting exoplanet candidates through traditional follow-up methods is challenging, especially for faint host stars. Most of Kepler's validated planets relied on statistical methods to separate true planets from false-positives. Multiple transiting planet systems (MTPS) have been previously shown to have low false-positive rates and over 851 planets in MTPSs have been statistically validated so far (Lissauer et al. 2014; Rowe et al. 2014). We show that the period-normalized transit duration ratio (?) offers additional information that can be used to establish the planetary nature of these systems. We briefly discuss the observed distribution of ? for the Q1-Q16 Kepler Candidate Search. We also utilize ? to develop a Bayesian statistical framework combined with Monte Carlo methods to determine which pairs of planet candidates in a MTPS are consistent with the planet hypothesis for a sample of 676 MTPSs that include both candidate and confirmed planets. This analysis proves to be efficient and advantageous in that it only requires catalog-level bulk candidate properties and galactic population modeling to compute the probabilities of a myriad of stellar blend scenarios, without needing additional observational follow-up. Our results agree with the previous results of a low false-positive rate in the Kepler MTPSs. Out of our sample of 1,358 pairs of candidates, we find that about 100 pairs have a probability greater than 0.99 of being a MTPS associated with the target star, over 800 pairs have a probability greater than 0.99 of being a MTPS associated with the target star or another star blended in the photometric aperture. Further more, we find that well over a 1,000 pairs have a probability greater than 0.99 to be planetary in nature, either orbiting the same star or separately orbiting two different stars in the aperture. This implies, independently of any other estimates, that most of the MTPSs detected by Kepler are very likely to be planetary in nature, but that a substantial fraction could be orbiting stars other than the putative target star, and therefore may be subject to significant error in the inferred planet parameters resulting from unknown or mismeasured stellar host attributes.

Morehead, Robert C.; Ford, Eric B.

2015-01-01

129

Carrier: Interference ratios for frequency sharing between satellite systems transmitting frequency modulated and digital television signals  

NASA Technical Reports Server (NTRS)

Results are presented of subjective and quantitative tests describing the results of interference to a particular digital television system from a frequency modulated (FM) television system, and for interference to an FM television system from a digital television system.

Barnes, S. P.

1979-01-01

130

A note on the systematics of noble gas abundance ratios in the solar system  

NASA Astrophysics Data System (ADS)

It is demonstrated that there is a general regularity in all noble gas elemental patterns in the atmospheres of the planets. A number of models are proposed to explain this, and these models are examined and judged. In order to explain the observed elemental gas ratios, it is proposed that they may have resulted from selective loss of noble gas from the initial atmospheres of the terrestrial or other planets; that they may be due to solar wind irradiation of the planets and their small precursor bodies; or the noble gases were imported by carrier grains with their peculiar abundance ratio already fixed.

Shukolyukov, Yu. A.

1991-04-01

131

A gas chromatography/pyrolysis/isotope ratio mass spectrometry system for high-precision dD measurements  

E-print Network

of greenhouse gases; however, little is known about their isotopic composition. In particular, stable sources exhibit distinct carbon and hydrogen isotopic composition. However, CH4 isotope analysisA gas chromatography/pyrolysis/isotope ratio mass spectrometry system for high-precision d

Fischer, Hubertus

132

Group Ratio Round-Robin: O(1) Proportional Share Scheduling for Uniprocessor and Multiprocessor Systems  

E-print Network

Group Ratio Round-Robin: O(1) Proportional Share Scheduling for Uniprocessor and Multiprocessor and practice. 1 Introduction Proportional share resource management provides a flexible and useful abstraction for multiplexing processor resources among a set of clients. Proportional share scheduling has a clear colloquial

Yang, Junfeng

133

Improvements in time resolution and signal-to-noise ratio in a compact pico-second pulse radiolysis system  

NASA Astrophysics Data System (ADS)

A compact pico-second pulse radiolysis system has been developing at Waseda University for studying primary processes in radiation chemistry. The system is composed of a photo-injector system and a pico-second all-solid-state laser system. An infrared (IR) and an ultraviolet (UV) laser pulses are obtained from mode-locked Nd:YLF laser system and used for generation of the white light continuum as a probe light and the irradiation to the Cu cathode of a photo-cathode RF-gun, respectively. To improve signal-to-noise (S/N) ratio and time resolution of this pulse radiolysis system, we optimized both probe light and pump electron beam. As a result, our pico-second pulse radiolysis system has been enough to study the primary processes of radiation chemistry. The experimental results and the improvements of our system are described in this paper.

Nagai, Hiroyuki; Kawaguchi, Masaaki; Sakaue, Kazuyuki; Komiya, Keita; Nomoto, Tomoaki; Kamiya, Yoshio; Hama, Yoshimasa; Washio, Masakazu; Ushida, Kiminori; Kashiwagi, Shigeru; Kuroda, Ryunosuke

2007-12-01

134

Technique to measure CO 2 mixing ratio in small flasks with a bellows\\/IRGA system  

Microsoft Academic Search

We developed a laboratory method to obtain high precision CO2 mixing ratios in air samples contained in 100ml glass flasks, which involves extracting air from the flask into a pre-evacuated manifold containing a variable-volume metal bellows. Compressed air from the bellows is then routed to a non-dispersive infrared gas analyzer (IRGA). Tests indicate that this configuration has an overall accuracy

D. R. Bowling; C. S. Cook; J. R. Ehleringer

2001-01-01

135

High compression ratio backward Raman conversion for high brightness excimer laser systems  

SciTech Connect

A new scheme of backward Raman pulse compression, in which the backward first Stokes pulse is amplified under stationary conditions and the backward second Stokes under transient conditions by choosing an appropriate Raman medium, is proposed. The compression factor and efficiency are improved by insertion of selective absorbers for the second Stokes component. The feasibility of such a scheme is demonstrated by an experiment in which a 249 nm UV pulse of 20 ns duration has been compressed into a 30-ps pulse with an power gain of 150 and energy conversion efficiency of 22%. Higher compression ratio and higher efficiency is expected by under improved conditions.

Nishioka, Hajime; Kimura, Kazuhiko; Ueda, Ken-ichi; Takuma, Hiroshi (Univ. of Electro-communications, Chofu, Tokyo (Japan))

1993-07-01

136

Tuning the current ratio of a CPV system to maximize the energy harvesting in a particular location  

NASA Astrophysics Data System (ADS)

A method based on experimental data is proposed to optimize the energy harvesting of a silicone-on-glass Fresnel-lens based CPV system. It takes into account the spectral variations along the year in a particular location as well as the thermal and spectral sensitivities of the optics and solar cell. In addition, different alternatives to tune the top/middle subcells current ratio in a CPV module are analyzed and their capacity to maximize the annually produced energy is quantified.

Victoria, M.; Askins, S.; Nuñez, R.; Domínguez, C.; Herrero, R.; Antón, I.; Sala, G.; Ruíz, J. M.

2013-09-01

137

Effects of Biofilter\\/Culture Tank Volume Ratios on Productivity of a Recirculating Fish\\/Vegetable Co-Culture System  

Microsoft Academic Search

The effects of four biofilter volume (BFV)\\/culture tank volume ratios (0.67\\/1, 1.00\\/1, 1.50\\/1, and 2.25\\/1) on biofilter function were examined in a recirculating fish\\/vegetable production system in a greenhouse. Sand beds served as biofilters, as substrate for vegetable growth, and as location for decomposition of waste solids. No fertilizer was used. Three experiments were conducted over the course of one

M. R. McMurtry; D. C. Sanders; J. D. Cure; R. G. Hodson

1997-01-01

138

Wind tunnel tests of high-lift systems for advanced transports using high-aspect-ratio supercritical wings  

NASA Technical Reports Server (NTRS)

The wind tunnel testing of an advanced technology high lift system for a wide body and a narrow body transport incorporating high aspect ratio supercritical wings is described. This testing has added to the very limited low speed high Reynolds number data base for this class or aircraft. The experimental results include the effects on low speed aerodynamic characteristics of various leading and trailing edge devices, nacelles and pylons, ailerons, and spoilers, and the effects of Mach and Reynolds numbers.

Allen, J. B.; Oliver, W. R.; Spacht, L. A.

1982-01-01

139

Micro-Bowen ratio system for measuring evapotranspiration in a vineyard interrow  

Technology Transfer Automated Retrieval System (TEKTRAN)

Sparse canopy systems such as vineyards are comprised of multiple components (e.g., vines, interrow soil and/or groundcover) that each contribute to system water and energy balance. Understanding component water and energy fluxes is critical for informing management decisions aimed at improving prod...

140

The molecular branching ratio method for calibration of optical systems in the vacuum ultraviolet  

NASA Technical Reports Server (NTRS)

The intensity distribution of bands belonging to six molecular band systems is discussed with special emphasis on their usefulness for intensity calibration of optical systems in the vacuum ultraviolet (1000A Lambda 3000A). The theory of molecular band intensities is outlined and the technique of measuring the spectral response curve is described. Several methods for establishing an absolute intensity calibration are discussed.

Mumma, M. J.

1972-01-01

141

Permanence and periodic solutions for an impulsive reaction-diffusion food-chain system with ratio-dependent functional response  

NASA Astrophysics Data System (ADS)

An impulsive reaction-diffusion periodic food-chain system with ratio-dependent functional response is investigated in the present paper. Sufficient conditions for the ultimate boundedness and permanence of the food-chain system are established based on the comparison theory of differential equation and upper and lower solution method. By constructing appropriate auxiliary function, the conditions for the existence of a unique globally stable positive periodic solution are also obtained. Some numerical examples are presented to verify our results. A discussion is given in the end of the paper.

Liu, Zijian; Zhong, Shouming; Liu, Xiaoyun

2014-01-01

142

The Role of Boron-Chloride and Noble Gas Isotope Ratios in TVZ Geothermal Systems  

SciTech Connect

The model of the geothermal system in which deep circulating groundwater containing noble gases, at air saturated water concentrations, mixes with hot fluids of mantle origin at depth, is extended to include the effect of interaction of the ascending fluid with both solid and gaseous phases of basement (or other) rocks en route to the surface. It is demonstrated that this interaction is responsible for most of the CO{sub 2} in the Taupo Volcanic Zone (TVZ) geothermal systems. It is proposed that the modeling of this interaction might be accomplished by techniques similar to those used for the understanding of the oxygen isotope shift found in geothermal systems. The water rock interaction experiments of Ellis and Mahon (1964, 1967) provides some data on the kinetic rates for B and Cl dissolution from rocks likely to be encountered in the geothermal system, but further information on the behavior of B may be needed. If these problems can be overcome this modeling technique has promise for the estimation of the recharge of geothermal systems and hence the sustainability of these systems.

Hulston, J.R.

1995-01-01

143

Deep, Low Mass Ratio Overcontact Binary Systems. XIII. DZ Piscium with Intrinsic Light Variability  

NASA Astrophysics Data System (ADS)

New multi-color photometry for the eclipsing binary DZ Psc was performed in 2011 and 2012 using the 85 cm telescope at the Xinglong Station of the National Astronomical Observatories of China. Using the updated Wilson-Devinney (W-D) code, we deduced two sets of photometric solutions. The overcontact degree is f = 89.7(± 1.0)%, identifying DZ Psc as a deep, low mass ratio overcontact binary. The asymmetric light curves (i.e., LC2 in 2012) were modeled by a hot spot on the primary star. Based on all of the available light minimum times, we discovered that the orbital period of DZ Psc may be undergoing a secular period increase with a cyclic variation. The modulated period and semi-amplitude of this oscillation are P mod = 11.89(± 0.19) yr and A = 0.0064(± 0.0006) days, which may be possibly attributed to either cyclic magnetic activity or light-time effect due to the third body. The long-term period increases at a rate of dP/dt=+7.43(+/- 0.17)\\times 10^{-7}{\\,days\\, yr^{-1}}, which may be interpreted as conserved mass transfer from the less massive component to the more massive one. With mass transferring, DZ Psc will finally merge into a rapid-rotation single star when J spin/J orb > 1/3.

Yang, Y.-G.; Qian, S.-B.; Zhang, L.-Y.; Dai, H.-F.; Soonthornthum, B.

2013-08-01

144

The effects of R/X ratios on power system minimum loss  

E-print Network

Impedanoe R/X ratio 124 28+3 56 125 8+$16 126 20+)40 ' 128 16+$32 129 32+) o 4 1/2 1/2 1/2 1/2 1/2 130 131 132 133 134 24+j48 124)24 8+$16 12+]24. 20+40 1/2 1/2 1/2 1/2 1/2 CASR V (a) X17 Angle (degrees) ?2R- TOTAL I X 2 I'Z PER... 109 111 5. o6 5 ' 74 b~Ob 11. 32 11. 48 12o12 12. 41 12. 82 13. 53 36 CASE W 5 A CTUAL LOSS yd VOLTAGE 7. 5 a 0 7. 0 4 5. 5 I' ll 5. 0 d. d 5. 0 101 105 l05 l07 I05 III X IT VOLTA55 37 CASE V (o) Con6itions: (1) X17 oonstant...

Denison, John Scott

1949-01-01

145

DEEP, LOW MASS RATIO OVERCONTACT BINARY SYSTEMS. XIII. DZ PISCIUM WITH INTRINSIC LIGHT VARIABILITY  

SciTech Connect

New multi-color photometry for the eclipsing binary DZ Psc was performed in 2011 and 2012 using the 85 cm telescope at the Xinglong Station of the National Astronomical Observatories of China. Using the updated Wilson-Devinney (W-D) code, we deduced two sets of photometric solutions. The overcontact degree is f = 89.7({+-} 1.0)%, identifying DZ Psc as a deep, low mass ratio overcontact binary. The asymmetric light curves (i.e., LC{sub 2} in 2012) were modeled by a hot spot on the primary star. Based on all of the available light minimum times, we discovered that the orbital period of DZ Psc may be undergoing a secular period increase with a cyclic variation. The modulated period and semi-amplitude of this oscillation are P{sub mod} = 11.89({+-} 0.19) yr and A = 0.0064({+-} 0.0006) days, which may be possibly attributed to either cyclic magnetic activity or light-time effect due to the third body. The long-term period increases at a rate of dP/dt=+7.43({+-}0.17) Multiplication-Sign 10{sup -7} days yr{sup -1}, which may be interpreted as conserved mass transfer from the less massive component to the more massive one. With mass transferring, DZ Psc will finally merge into a rapid-rotation single star when J{sub spin}/J{sub orb} > 1/3.

Yang, Y.-G.; Dai, H.-F. [School of Physics and Electronic Information, Huaibei Normal University, 235000 Huaibei, Anhui Province (China); Qian, S.-B. [National Astronomical Observatories/Yunnan Observatory, Chinese Academy of Sciences, 650011 Kunming (China); Zhang, L.-Y. [Department of Physics, College of Science, Guizhou University, 550025 Guiyang (China); Soonthornthum, B., E-mail: yygcn@163.com, E-mail: qsb@ynao.ac.cn [National Astronomical Research Institute of Thailand/Ministry of Science and Technology, Bangkok (Thailand)

2013-08-01

146

Modeling percolation in high-aspect-ratio fiber systems. I. Soft-core versus hard-core models.  

PubMed

Numerical and analytical studies of the onset of percolation in high-aspect-ratio fiber fiber systems such as nanotube reinforced polymers available in the literature have consistently modeled fibers as penetrable, straight, capped cylinders, also referred to as spherocylinders. In reality, however, fibers of very high-aspect ratio embedded in a polymer do not come into direct physical contact with each other, let alone exhibit any degree of penetrability. Further, embedded fibers of very high-aspect ratio are often actually wavy, rather than straight. In this two-part paper we address these critical differences between known physical systems, and the presently used spherocylinder percolation model. In Paper I we evaluate the effect of allowing penetration of the model fibers on simulation results by comparing the soft-core and the hard-core approaches to modeling percolation onset. We use Monte Carlo simulations to investigate the relationship between percolation threshold and excluded volume for both modeling approaches. Our results show that the generally accepted inverse proportionality between percolation threshold and excluded volume holds for both models. We further demonstrate that the error introduced by allowing the fibers to intersect is non-negligible, and is a function of both aspect ratio and tunneling distance. Thus while the results of both the soft-core model and hard-core assumptions can be matched to select experimental results, the hard-core model is more appropriate for modeling percolation in nanotubes-reinforced composites. The hard-core model can also potentially be used as a tool in calculating the tunneling distance in composite materials, given the fiber morphology and experimentally derived electrical percolation threshold. In Paper II we investigate the effect of the waviness of the fibers on the onset of percolation in fiber reinforced composites. PMID:17500878

Berhan, L; Sastry, A M

2007-04-01

147

Selenium stable isotope ratios in California agricultural drainage water management systems  

USGS Publications Warehouse

Selenium stable isotope ratios are known to shift in predictable ways during various microbial, chemical, and biological processes, and can be used to better understand Se cycling in contaminated environments. In this study we used Se stable isotopes to discern the mechanisms controlling the transformation of oxidized, aqueous forms of Se to reduced, insoluble forms in sediments of Se-affected environments. We measured 80Se/76Se in surface waters, shallow ground waters, evaporites, digested plants and sediments, and sequential extracts from several sites where agricultural drainage water is processed in the San Joaquin Valley of California. Selenium isotope analyses of samples obtained from the Tulare Lake Drainage District flow-through wetland reveal small isotopic contrasts (mean difference 0.7%o) between surface water and reduced Se species in the underlying sediments. Selenium in aquatic macrophytes was very similar isotopically to the NaOH and Na2SO3 sediment extracts designed to recover soluble organic Se and Se(O), respectively. For the integrated on-farm drainage management sites, evaporite salts were slightly (approximately 0.6%o) enriched in the heavier isotope relative to the inferred parent waters, whereas surface soils were slightly (approximately 1.4%o) depleted. Bacterial or chemical reduction of Se(VI) or Se(IV) may be occurring at these sites, but the small isotopic contrasts suggest that other, less isotopically fractionating mechanisms are responsible for accumulation of reduced forms in the sediments. These findings provide evidence that Se assimilation by plants and algae followed by deposition and mineralization is the dominant transformation pathway responsible for accumulation of reduced forms of Se in the wetland sediments.

Herbel, M.J.; Johnson, T.M.; Tanji, K.K.; Gao, S.; Bullen, T.D.

2002-01-01

148

Selenium stable isotope ratios in California agricultural drainage water management systems.  

PubMed

Selenium stable isotope ratios are known to shift in predictable ways during various microbial, chemical, and biological processes, and can be used to better understand Se cycling in contaminated environments. In this study we used Se stable isotopes to discern the mechanisms controlling the transformation of oxidized, aqueous forms of Se to reduced, insoluble forms in sediments of Se-affected environments. We measured 80Se/76Se in surface waters, shallow ground waters, evaporites, digested plants and sediments, and sequential extracts from several sites where agricultural drainage water is processed in the San Joaquin Valley of California. Selenium isotope analyses of samples obtained from the Tulare Lake Drainage District flow-through wetland reveal small isotopic contrasts (mean difference 0.7%) between surface water and reduced Se species in the underlying sediments. Selenium in aquatic macrophytes was very similar isotopically to the NaOH and Na2SO3 sediment extracts designed to recover soluble organic Se and Se(0), respectively. For the integrated on-farm drainage management sites, evaporite salts were slightly (approximately 0.6%) enriched in the heavier isotope relative to the inferred parent waters, whereas surface soils were slightly (approximately 1.4%) depleted. Bacterial or chemical reduction of Se(VI) or Se(IV) may be occurring at these sites, but the small isotopic contrasts suggest that other, less isotopically fractionating mechanisms are responsible for accumulation of reduced forms in the sediments. These findings provide evidence that Se assimilation by plants and algae followed by deposition and mineralization is the dominant transformation pathway responsible for accumulation of reduced forms of Se in the wetland sediments. PMID:12175032

Herbel, Mitchell J; Johnson, Thomas M; Tanji, Kenneth K; Gao, Suduan; Bullen, Thomas D

2002-01-01

149

The optimal design of robot drive system-gear ratios and actuator impedances  

Microsoft Academic Search

Robots are employed in flexible manufacturing systems. More robots of better performance are needed for a variety of industrial applications. This paper focuses on designing the manipulator-drive assembly having the desirable properties of quick dynamic response and isotroplc velocity convergence to improve the robot performances and partially satisfy those needs. The design variables are identified to be functions of gear

Ching-Cheng Wang

1986-01-01

150

36Cl/Cl ratios in geothermal systems: preliminary measurements from the Coso Field  

SciTech Connect

The {sub 36}Cl/Cl isotopic composition of chlorine in geothermal systems can be a useful diagnostic tool in characterizing hydrologic structure, in determining the origins and age of waters within the systems, and in differentiating the sources of chlorine (and other solutes) in the thermal waters. The {sub 36}Cl/Cl values for several geothermal water samples and reservoir host rock samples from the Coso, California geothermal field have been measured for these purposes. The results indicate that most of the chlorine is not derived from the dominant granitoid that host the geothermal system. If the chlorine was originally input into the Coso subsurface through meteoric recharge, that input occurred at least 1-1.25 million years ago. The results suggest that the thermal waters could be connate waters derived from sedimentary formations, presumably underlying and adjacent top the granitic rocks, which have recently migrated into the host rocks. Alternatively, most of the chlorine but not the water, may have recently input into the system from magmatic sources. In either case, the results indicate that most of the chlorine in the thermal waters has existed within the granitoid host rocks for no more than about 100,00-200,00 years. this residence time for the chlorine is similar to residence times suggested by other researchers for chlorine in deep groundwaters of the Mono Basin north of the Coso field.

Nimz, G.J.; Moore, J.N.; Kasameyer, P.W.

1997-07-01

151

RELATIONSHIP BETWEEN HVAC SYSTEM OPERATION, AIR EXCHANGE RATE, AND INDOOR-OUTDOOR PARTICULATE MATTER RATIOS  

EPA Science Inventory

Measurements of duty cycle , the fraction of time the heating and cooling (HVAC) system was operating, were made in each participant's home during the spring season of the RTP Particulate Matter Panel Study. A miniature temperature sensor/data logger combination placed on the ...

152

Modeling percolation in high-aspect-ratio fiber systems. I. Soft-core versus hard-core models L. Berhan1,  

E-print Network

cellulose 13,14 and other biological fibers. More recent work, by Sastry and co-workers, has resulted fromModeling percolation in high-aspect-ratio fiber systems. I. Soft-core versus hard-core models L-aspect-ratio fiber fiber systems such as nanotube reinforced polymers available in the literature have consistently

Sastry, Ann Marie

153

Lightning Ratios  

NSDL National Science Digital Library

Using satellites and ground-based detection instruments, researchers have now mapped out lightning ratios for the continental United States. The Lightning Ratios site, from Space Science News (NASA), provides recent data in the form of a vibrant color map (.pdf or .jpg) of cloud-to-cloud lightning to cloud-to-ground lightning over the continental United States.

154

Rod Ratios  

NSDL National Science Digital Library

This activity builds student knowledge of ratios by using Cuisenaire rods to determine proportion and form equivalent ratios. Students may use the Cuisenaire rod environment embedded in this resource or they may use actual Cuisenaire rods depending on preference/ability/accessibility. This resource includes teacher notes, solution, and suggestions for questioning.

Team, Nrich

2013-01-01

155

Photometric study and preliminary elements of the low-mass ratio W UMa system ASAS 021209+2708.3  

NASA Astrophysics Data System (ADS)

We present CCD B and V light curves, obtained in the year 2006, and a photometric solution of the low-mass ratio contact binary ASAS 021209+2708.3. With our data we were able to determine six new times of minimum light and refine the orbital period of the system to 0.3181963 days. The light curves are analyzed using the 2003 version of the Wilson-Devinney program and the analysis was performed with and without adding a spot on the surface of one star because the light curves appear to exhibit a typical O'Connell effect, with Maximum I brighter than Maximum II. The results show that ASAS 021209+2708.3 may be classified as an A-subtype W Ursae Majoris system with a small mass ratio q = 0.1889, a large over-contact degree of f = 0.587, a very small difference between the component temperatures of ?T = 53 K and an orbital inclination of i = 81°. It is known that deep (f > 50%), low-mass ratio (q < 0.25) overcontact binary stars are a very important resource for understanding the phenomena of Blue Straggler/FK Com-type stars. The formations of Blue Straggler stars and FK Com-type stars are unsolved problems in stellar astrophysics. One of the possible explanations for their formation is from the coalescence of W UMa-type overcontact binary systems. The absolute dimensions of ASAS 021209+2708.3 are estimated and its dynamical evolution is inferred.

Acerbi, Francesco; Barani, Carlo; Martignoni, Massimiliano

2011-07-01

156

A five-collector system for the simultaneous measurement of argon isotope ratios in a static mass spectrometer  

USGS Publications Warehouse

A system is described that utilizes five separate Faraday-cup collector assemblies, aligned along the focal plane of a mass spectrometer, to collect simultaneous argon ion beams at masses 36-40. Each collector has its own electrometer amplifier and analog-to-digital measuring channel, the outputs of which are processed by a minicomputer that also controls the mass spectrometer. The mass spectrometer utilizes a 90?? sector magnetic analyzer with a radius of 23 cm, in which some degree of z-direction focussing is provided for all the ion beams by the fringe field of the magnet. Simultaneous measurement of the ion beams helps to eliminate mass-spectrometer memory as a significant source of measurement error during an analysis. Isotope ratios stabilize between 7 and 9 s after sample admission into the spectrometer, and thereafter changes in the measured ratios are linear, typically to within ??0.02%. Thus the multi-collector arrangement permits very short extrapolation times for computation of initial ratios, and also provides the advantages of simultaneous measurement of the ion currents in that errors due to variations in ion beam intensity are minimized. A complete analysis takes less than 10 min, so that sample throughput can be greatly enhanced. In this instrument, the factor limiting analytical precision now lies in short-term apparent variations in the interchannel calibration factors. ?? 1981.

Stacey, J.S.; Sherrill, N.D.; Dalrymple, G.B.; Lanphere, M.A.; Carpenter, N.V.

1981-01-01

157

Compact point-detection fluorescence spectroscopy system for quantifying intrinsic fluorescence redox ratio in brain cancer diagnostics  

PubMed Central

We report the development of a compact point-detection fluorescence spectroscopy system and two data analysis methods to quantify the intrinsic fluorescence redox ratio and diagnose brain cancer in an orthotopic brain tumor rat model. Our system employs one compact cw diode laser (407 nm) to excite two primary endogenous fluorophores, reduced nicotinamide adenine dinucleotide, and flavin adenine dinucleotide. The spectra were first analyzed using a spectral filtering modulation method developed previously to derive the intrinsic fluorescence redox ratio, which has the advantages of insensitivty to optical coupling and rapid data acquisition and analysis. This method represents a convenient and rapid alternative for achieving intrinsic fluorescence-based redox measurements as compared to those complicated model-based methods. It is worth noting that the method can also extract total hemoglobin concentration at the same time but only if the emission path length of fluorescence light, which depends on the illumination and collection geometry of the optical probe, is long enough so that the effect of absorption on fluorescence intensity due to hemoglobin is significant. Then a multivariate method was used to statistically classify normal tissues and tumors. Although the first method offers quantitative tissue metabolism information, the second method provides high overall classification accuracy. The two methods provide complementary capabilities for understanding cancer development and noninvasively diagnosing brain cancer. The results of our study suggest that this portable system can be potentially used to demarcate the elusive boundary between a brain tumor and the surrounding normal tissue during surgical resection. PMID:21456877

Liu, Quan; Grant, Gerald; Li, Jianjun; Zhang, Yan; Hu, Fangyao; Li, Shuqin; Wilson, Christy; Chen, Kui; Bigner, Darell; Vo-Dinh, Tuan

2011-01-01

158

Compact point-detection fluorescence spectroscopy system for quantifying intrinsic fluorescence redox ratio in brain cancer diagnostics  

NASA Astrophysics Data System (ADS)

We report the development of a compact point-detection fluorescence spectroscopy system and two data analysis methods to quantify the intrinsic fluorescence redox ratio and diagnose brain cancer in an orthotopic brain tumor rat model. Our system employs one compact cw diode laser (407 nm) to excite two primary endogenous fluorophores, reduced nicotinamide adenine dinucleotide, and flavin adenine dinucleotide. The spectra were first analyzed using a spectral filtering modulation method developed previously to derive the intrinsic fluorescence redox ratio, which has the advantages of insensitivty to optical coupling and rapid data acquisition and analysis. This method represents a convenient and rapid alternative for achieving intrinsic fluorescence-based redox measurements as compared to those complicated model-based methods. It is worth noting that the method can also extract total hemoglobin concentration at the same time but only if the emission path length of fluorescence light, which depends on the illumination and collection geometry of the optical probe, is long enough so that the effect of absorption on fluorescence intensity due to hemoglobin is significant. Then a multivariate method was used to statistically classify normal tissues and tumors. Although the first method offers quantitative tissue metabolism information, the second method provides high overall classification accuracy. The two methods provide complementary capabilities for understanding cancer development and noninvasively diagnosing brain cancer. The results of our study suggest that this portable system can be potentially used to demarcate the elusive boundary between a brain tumor and the surrounding normal tissue during surgical resection.

Liu, Quan; Grant, Gerald; Li, Jianjun; Zhang, Yan; Hu, Fangyao; Li, Shuqin; Wilson, Christy; Chen, Kui; Bigner, Darell; Vo-Dinh, Tuan

2011-03-01

159

Measurement and Evaluation of 3-D Structure in Low-Aspect-Ratio RFP RELAX with Dual SXR Imaging System  

NASA Astrophysics Data System (ADS)

The high-speed soft X-ray (SXR) imaging system has been extended to take the images from tangential and vertical directions simultaneously to observe three-dimensional (3-D) dynamic structures of the SXR emissivity. A preliminary experimental resultin which we observed SXR images from the quasi-periodic quasi-single helicity (QSH) and multi-helicity (MH) states in low-aspect-ratio (low-A) reversed field pinch (RFP) plasmas is presented. Calculated magnetic configuration suggests existence of a large magnetic island in shallow reversal discharge.

Sanpei, Akio; Nishimura, Kanae; Masamune, Sadao; Tanaka, Hiroyuki; Himura, Haruhiko; Ohdachi, Satoshi; Mizuguchi, Naoki; Akiyama, Tsuyoshi

160

Problems of trace element ratios and geothermometry in a gravel geothermal-aquifer system  

SciTech Connect

A Tertiary-age, block-faulted basin in which a Pleistocene gravel bed acts as a confined aquifer and permits the lateral dispersion of the geothermal fluids is studied. Basic data on geology and trace element holes presented previously are reproduced along with fluoride data. Evaluation of the phenomena in this system was attempted using a dissolved silica-enthalpy graph. A chalcedomy curve is also plotted. An enthalpy versus chloride plot suggests that either conductive cooling occurs before mixing or that higher chloride content background waters are available for mixing. (MHR)

Sonderegger, J.L.; Donovan, J.J.; Ruscetta, C.A.; Foley, D. (eds.)

1981-05-01

161

Calibration of high-aspect ratio quality control optical scanning system  

NASA Astrophysics Data System (ADS)

Gas electron multiplier (GEM) detectors are widely used in contemporary high-energy physics experiments. The GEM is a detector containing a densely pierced polymer foil, coated with a thin metal layer on one or both sides. They are able to achieve high amplification gains and performance at low cost, even under harsh radiation conditions. The holes in the foils have a nominal diameter of 70 +/- 5 ?m and 140 ?m pitch distance between the centers of the holes. High-quality assurance is needed to guarantee a long lifespan for the detectors in the severe radiation environment. Mapping of the defects connecting two or more holes is important phase when determining the usability of a foil for detector application. The commercial optical scanning system (OSS) with a scanning area of 950 × 950 mm was further developed in the Detector Laboratory at Helsinki Institute of Physics for controlling the quality of GEM foils. Microfabricated transfer standard containing sets of 10 × 10 numbered etched cavities with a nominal diameter of 70 +/- 5 ?m was produced for system calibration. The cavity dimensions and the expanded uncertainty were calculated with the 95% confidence level, as is required by the ISO Guide for Expression of Uncertainty in Measurement. The transfer standard was examined with the OSS in nine different positions of the scanning area. The results were analyzed, the uncertainties were calculated and the corrections were made according to the ISO requirement.

Karadzhinova, Aneliya; Hildén, Timo; Heino, Jouni; Berdova, Maria; Lauhakangas, Rauno; Garcia, Francisco; Tuominen, Eija; Kassamakov, Ivan

2013-09-01

162

Mechanical Design of High Lift Systems for High Aspect Ratio Swept Wings  

NASA Technical Reports Server (NTRS)

The NASA Ames Research Center is working to develop a methodology for the optimization and design of the high lift system for future subsonic airliners with the involvement of two partners. Aerodynamic analysis methods for two dimensional and three dimensional wing performance with flaps and slats deployed are being developed through a grant with the aeronautical department of the University of California Davis, and a flap and slat mechanism design procedure is being developed through a contract with PKCR, Inc., of Seattle, WA. This report documents the work that has been completed in the contract with PKCR on mechanism design. Flap mechanism designs have been completed for seven (7) different mechanisms with a total of twelve (12) different layouts all for a common single slotted flap configuration. The seven mechanisms are as follows: Simple Hinge, Upside Down/Upright Four Bar Linkage (two layouts), Upside Down Four Bar Linkages (three versions), Airbus A330/340 Link/Track Mechanism, Airbus A320 Link/Track Mechanism (two layouts), Boeing Link/Track Mechanism (two layouts), and Boeing 767 Hinged Beam Four Bar Linkage. In addition, a single layout has been made to investigate the growth potential from a single slotted flap to a vane/main double slotted flap using the Boeing Link/Track Mechanism. All layouts show Fowler motion and gap progression of the flap from stowed to a fully deployed position, and evaluations based on spanwise continuity, fairing size and number, complexity, reliability and maintainability and weight as well as Fowler motion and gap progression are presented. For slat design, the options have been limited to mechanisms for a shallow leading edge slat. Three (3) different layouts are presented for maximum slat angles of 20 deg, 15 deg and 1O deg all mechanized with a rack and pinion drive similar to that on the Boeing 757 airplane. Based on the work of Ljungstroem in Sweden, this type of slat design appears to shift the lift curve so that higher lift is achieved with the deployed slat with no increase in angle of attack. The layouts demonstrate that these slat systems can be designed with no need for slave links, and an experimental test program is outlined to experimentally validate the lift characteristics of the shallow slat.

Rudolph, Peter K. C.

1998-01-01

163

Colony sex ratios vary with breeding system but not relatedness asymmetry in the facultatively polygynous ant Pheidole pallidula.  

PubMed

We investigated sex allocation in a Mediterranean population of the facultatively polygynous (multiple queen per colony) ant Pheidole pallidula. This species shows a strong split sex ratio, with most colonies producing almost exclusively a single-sex brood. Our genetic (microsatellite) analyses reveal that P. pallidula has an unusual breeding system, with colonies being headed by a single or a few unrelated queens. As expected in such a breeding system, our results show no variation in relatedness asymmetry between monogynous (single queen per colony) and polygynous colonies. Nevertheless, sex allocation was tightly associated with the breeding structure, with monogynous colonies producing a male-biased brood and polygynous colonies almost only females. In addition, sex allocation was closely correlated with colony total sexual productivity. Overall, our data show that when colonies become more productive (and presumably larger) they shift from monogyny to polygyny and from male production to female production, a pattern that has never been reported in social insects. PMID:12894941

Fournier, Denis; Keller, Laurent; Passera, Luc; Aron, Serge

2003-06-01

164

Analysis of linewidth and extinction ratio in directly modulated lasers for performance optimization in 10 Gbit/s CWDM systems  

NASA Astrophysics Data System (ADS)

Direct Modulation Lasers (DMLs) have attracted increased attention during the past few years because of their intrinsic simplicity and cost-effectiveness, especially when applied to WDM metro and access networks. However, the output power waveform from a directly modulated laser is not an exact replica of the modulation current and its instantaneous optical frequency varies with time depending on the changes in optical power and the extinction ratio (ER) (an effect also known as frequency chirp). In this work, using an Optical Communication System Design Software, we have studied a directly modulated WDM 10 Gb/s system which transmission performance depends strongly on DML characteristics; simulation results have provided supplementary details about the effects of DML type (adiabatic or transient chirp dominated) as well as the effects of the optical output power. These details can provide useful design guidelines for constructing a WDM metro network.

Campos, Carmina del Río; Horche, Paloma R.; Martin-Minguez, Alfredo

2010-08-01

165

A post-coding scheme for peak-to-average power ratio reduction in intensity modulated optical OFDM systems  

NASA Astrophysics Data System (ADS)

An efficient post-coding strategy is proposed in this letter to reduce the peak-to-average power ratio (PAPR) of orthogonal frequency division multiplexing (OFDM) signals for optical intensity modulated direct detection (IM/DD) systems. The post-coding scheme based on discrete cosine transform (DCT) is employed after the inverse fast Fourier transform (IFFT) in the transmitter to reduce the PAPR of OFDM signals. This method is different from the conventional pre-coding scheme which is employed before IFFT operation. Numerical simulations demonstrate that the new DCT post-coding strategy can significantly reduce the PAPR than the conventional pre-coding scheme. Meantime, the bit error rate (BER) performance of the proposed post-coding system can be improved compared with the conventional pre-coding scheme.

Chen, Fang-ni; Wang, Zhong-peng

2014-07-01

166

Signal-to-noise ratio estimation in digital computer simulation of lowpass and bandpass systems with applications to analog and digital communications, volume 3  

NASA Technical Reports Server (NTRS)

Techniques are developed to estimate power gain, delay, signal-to-noise ratio, and mean square error in digital computer simulations of lowpass and bandpass systems. The techniques are applied to analog and digital communications. The signal-to-noise ratio estimates are shown to be maximum likelihood estimates in additive white Gaussian noise. The methods are seen to be especially useful for digital communication systems where the mapping from the signal-to-noise ratio to the error probability can be obtained. Simulation results show the techniques developed to be accurate and quite versatile in evaluating the performance of many systems through digital computer simulation.

Tranter, W. H.; Turner, M. D.

1977-01-01

167

An analysis of trading ratio for water pollution control trading systems using a geographic information system and the finite segment method  

NASA Astrophysics Data System (ADS)

Nitrogen from non-point sources reacts with the environment during flow to the waterway. These reactions cause decay of the pollutant. There is a question regarding whether pollution trades between point sources and non-point sources that involve nitrogen should consider this decay. The failure to consider this decay may cause trades to fail to achieve their environmental goal or to inefficiently achieve their environmental goal. Additionally, planners may consider the decay to target reductions and improve efficiency of trading programs. The dissertation uses a geographic information system (GIS) and the finite segment method to evaluate the need for the use of a trading ratio to consider decay. It uses GIS, principles of process engineering, and principles of hydrology to model the distribution of the nitrogen in the watershed with and without decay. Additionally, it compares the predictions of the concentrations with and without decay. Finally, it uses GIS to estimate appropriate values of trading ratio. The results show that the effect from decay during overland flow is appreciable but not always significant. The appropriate values of trading ratio are likely to be less than 1.3. Use of trading ratio may protect environmental quality and improve the efficiency of pollution control. However, sometimes the values of trading ratios are small relative to other factors so that the use of trading ratio is inconsequential. Finally, planners may use the decay of nitrogen from non-point sources to target the locations of the reductions to achieve the maximum decrease of concentration or to achieve the maximum increase of load without an increase in concentration.

Curley, Donald Edward

168

Digit ratio 2D:4D in relation to autism spectrum disorders, empathizing, and systemizing: a quantitative review.  

PubMed

Prenatal testosterone (PT) effects have been proposed to increase systemizing (the drive to understand lawful input-output relationships), to decrease empathizing (the drive to understand others), and to cause autism via hypermasculinization of the brain. Digit ratio 2D:4D is a putative marker of PT effects in humans. An online study (n = 1896) into the relationship between the Reading the Mind in the Eyes Test (a widely used measure of empathizing) and self-measured 2D:4D in a nonclinical sample is reported. No evidence for a link between empathizing and 2D:4D in either females or males emerged. Further, three meta-analyses are presented that look into the relationships of 2D:4D with autism spectrum disorder (ASD), systemizing, and empathizing. 2D:4D was substantially lower (more masculine) in ASD-affected individuals than in normal controls (d = -0.58, P < 0.001). However, 2D:4D was found to be virtually unrelated to systemizing and empathizing in normal adults. The results support the idea that high PT is a risk factor for autism, but they challenge the view that PT substantially contributes to sex differences in systemizing and empathizing. Possibly, this pattern reflects an interaction effect, whereby PT drives ASD characteristic changes only in brains with a specific damage. PMID:22674640

Hönekopp, Johannes

2012-08-01

169

A short-standoff bistatic lidar system for aerosol cloud backscatter and fluorescence cross section, and depolarization ratio measurement  

NASA Astrophysics Data System (ADS)

We have designed a short-standoff bistatic lidar system, used for the direct measurement of the optical backscatter at 355-nm and 1064-nm and laser induced fluorescence (LIF) cross sections as well as depolarization ratio of aerosols inside a vacuum sealed, aerosol flow chamber. The 355- and 1064-nm beams are sent through the aerosol chamber at an angle of ~2° with respect to the field of view of the receiver optics to ensure that measurements reflect true backscatter. This bistatic lidar configuration naturally defines a limited region in space where the laser beams and the receiver field of view overlap, a region that can be easily quantified using a standard calibration procedure. Our technique also takes advantage of a specially designed vacuum sealed, aerosol flow chamber that provides a well-mixed, uniform aerosol distribution over the region of sensitivity. Both modeling results and experimental measurements confirm that little particle loss is observed inside the aerosol flow chamber. A TSI aerodynamic particle sizer (APS) is used to measure the aerosol concentration in the chamber, and the N2 concentration can be calculated using the measured temperature and pressure of the air inside the chamber. Optical backscatter and LIF cross sections are determined by comparing the measured elastic and LIF signals with the N2 Raman scattering signal from the same sample volume, a technique which eliminates the need for absolute radiometric calibration of the system. Instead, all detectors in the system are calibrated relative to the N2 Raman channel and the unknown aerosol cross sections are determined by taking the ratio of the backscatter (or LIF) signals to the Raman signal and multiplying by the well-known Raman cross section of N2. Particulate population depolarization parameters are determined by measuring the rejected polarized light from a Glan Laser prism polarizer and comparing those intensity measurements with that of the direct backscatter intensity. This work will focus on particle specific optical backscatter cross-sections and depolarization ratios for atmospherically relevant particle populations including Arizona road dust, black carbon, ammonium sulfate, and sodium chloride. Preliminary results of the absolute scattering cross-section and polarization parameters will be presented. Sandia National Laboratories is a multi-program laboratory operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000.

Glen, C.; Schmitt, R. L.; Sickafoose, S.; Johnson, M. S.; Shagam, R.; Reichardt, T.; Sanchez, A.; Servantes, B.

2012-12-01

170

Plant lighting system with five wavelength-band light-emitting diodes providing photon flux density and mixing ratio control  

PubMed Central

Background Plant growth and development depend on the availability of light. Lighting systems therefore play crucial roles in plant studies. Recent advancements of light-emitting diode (LED) technologies provide abundant opportunities to study various plant light responses. The LED merits include solidity, longevity, small element volume, radiant flux controllability, and monochromaticity. To apply these merits in plant light response studies, a lighting system must provide precisely controlled light spectra that are useful for inducing various plant responses. Results We have developed a plant lighting system that irradiated a 0.18 m2 area with a highly uniform distribution of photon flux density (PFD). The average photosynthetic PFD (PPFD) in the irradiated area was 438 micro-mol m–2 s–1 (coefficient of variation 9.6%), which is appropriate for growing leafy vegetables. The irradiated light includes violet, blue, orange-red, red, and far-red wavelength bands created by LEDs of five types. The PFD and mixing ratio of the five wavelength-band lights are controllable using a computer and drive circuits. The phototropic response of oat coleoptiles was investigated to evaluate plant sensitivity to the light control quality of the lighting system. Oat coleoptiles irradiated for 23 h with a uniformly distributed spectral PFD (SPFD) of 1 micro-mol m–2 s–1 nm–1 at every peak wavelength (405, 460, 630, 660, and 735 nm) grew almost straight upwards. When they were irradiated with an SPFD gradient of blue light (460 nm peak wavelength), the coleoptiles showed a phototropic curvature in the direction of the greater SPFD of blue light. The greater SPFD gradient induced the greater curvature of coleoptiles. The relation between the phototropic curvature (deg) and the blue-light SPFD gradient (micro-mol m–2 s–1 nm–1 m–1) was 2 deg per 1 micro-mol m–2 s–1 nm–1 m–1. Conclusions The plant lighting system, with a computer with a graphical user interface program, can control the PFD and mixing ratios of five wavelength-band lights. A highly uniform PFD distribution was achieved, although an intentionally distorted PFD gradient was also created. Phototropic responses of oat coleoptiles to the blue light gradient demonstrated the merit of fine controllability of this plant lighting system. PMID:23173915

2012-01-01

171

Characterization Of High-Stroke High-Aspect Ratio Micro Electro Mechanical Systems Deformable Mirrors For Adaptive Optics  

NASA Astrophysics Data System (ADS)

Adaptive optics MEMS deformable mirror, in conjunction with Shack Hartman wave front sensor and real-time controller, is capable of correcting time-varying aberrations in imaging applications through manipulating its mirror surface. Adaptive optics systems in astronomy for next generation large telescopes (30 meter primary mirrors) require a high stroke of 10microm of mechanical displacement. This required stroke would be achieved by MEMS deformable mirrors fabricated with high aspect ratio techniques. This thesis will review the designs of various types of high aspect actuators consisting of folded springs with rectangular and circular membranes as well as X-beam actuators. Finite element analysis (FEA) simulations of these designs have shown the ability of each design to achieve a stroke of approximately 9.4 microm. Also, FEA simulations proved that the X-beam actuators provide the best spring support while preventing tilting. In addition, this thesis will discuss device characterization and voltage vs. displacement test results for the high aspect ratio gold MEMS 16 x 16 X-beam actuators deformable mirror that has been bonded and packaged. The results have shown that the device is capable of achieving approximately 5.5 microm in individual actuator testing and 7microm in dual actuator testing.

Bouchti, Mohamed Amine

172

HIGH FILL-OUT, EXTREME MASS RATIO OVERCONTACT BINARY SYSTEMS. X. THE NEWLY DISCOVERED BINARY XY LEONIS MINORIS  

SciTech Connect

The newly discovered short-period close binary star, XY LMi, has been monitored photometrically since 2006. Its light curves are typical EW-type light curves and show complete eclipses with durations of about 80 minutes. Photometric solutions were determined through an analysis of the complete B, V, R, and I light curves using the 2003 version of the Wilson-Devinney code. XY LMi is a high fill-out, extreme mass ratio overcontact binary system with a mass ratio of q = 0.148 and a fill-out factor of f = 74.1%, suggesting that it is in the late evolutionary stage of late-type tidal-locked binary stars. As observed in other overcontact binary stars, evidence for the presence of two dark spots on both components is given. Based on our 19 epochs of eclipse times, we found that the orbital period of the overcontact binary is decreasing continuously at a rate of dP/dt = -1.67 x 10{sup -7} days yr{sup -1}, which may be caused by mass transfer from the primary to the secondary and/or angular momentum loss via magnetic stellar wind. The decrease of the orbital period may result in the increase of the fill-out, and finally, it will evolve into a single rapid-rotation star when the fluid surface reaches the outer critical Roche lobe.

Qian, S.-B.; Liu, L.; Zhu, L.-Y.; He, J.-J. [National Astronomical Observatories/Yunnan Astronomical Observatory, Chinese Academy of Sciences (CAS), P.O. Box 110, 650011 Kunming (China); Yang, Y.-G. [School of Physics and Electric Information, Huaibei Coal Industry Teachers College, 235000 Huaibei, Anhui Province (China); Bernasconi, L., E-mail: qsb@ynao.ac.cn, E-mail: yygcn@163.com, E-mail: laurent.bernasconi.51@wanadoo.fr [Les Engarouines Observatory, F-84570 Malemort-du-Comtat (France)

2011-05-15

173

Disentangling community functional components in a litter-macrodetritivore model system reveals the predominance of the mass ratio hypothesis  

PubMed Central

Recent investigations have shown that two components of community trait composition are important for key ecosystem processes: (i) the community-weighted mean trait value (CWM), related to the mass ratio hypothesis and dominant trait values in the community, and (ii) functional diversity (FD), related to the complementarity hypothesis and the divergence of trait values. However, no experiments controlling for the inherent dependence between CWM and FD have been conducted so far. We used a novel experimental framework to disentangle the unique and shared effects of CWM and FD in a leaf litter-macrodetritivore model system. We manipulated isopod assemblages varying in species number, CWM and FD of litter consumption rate to test the relative contribution of these community parameters in the decomposition process. We showed that CWM, but also the combination of CWM and FD, is a main factor controlling litter decomposition. When we tested individual biodiversity components separately, CWM of litter consumption rate showed a significant effect on decomposition, while FD and species richness alone did not. Our study demonstrated that (i) trait composition rather than species diversity drives litter decomposition, (ii) dominant trait values in the community (CWM) play a chief role in driving ecosystem processes, corroborating the mass ratio hypothesis, and (iii) trait dissimilarity can contribute in modulating the overall biodiversity effects. Future challenge is to assess whether the generality of our finding, that is, that dominant trait values (CWM) predominate over trait dissimilarity (FD), holds for other ecosystem processes, environmental conditions and different spatial and temporal scales. PMID:24634725

Bílá, Karolína; Moretti, Marco; Bello, Francesco; Dias, André TC; Pezzatti, Gianni B; Van Oosten, Arend Raoul; Berg, Matty P

2014-01-01

174

Carrier-interference ratios for frequency sharing between frequency-modulated amplitude-modulated-vestigial-sideband television systems  

NASA Technical Reports Server (NTRS)

For just perceptible interference, an FM television signal interfering with another FM television signal must have an average signal power that is 26 to 37 db less than the wanted signal power. For an AM-VSB television signal interfering with an FM television signal, the AM-VSB television's sync peak average power must be 18 to 31 db below the FM television signal's average power. Also, when an FM television signal interferes with an AM-VSB signal, the average signal power of the FM signal should be 56 to 59 db below the sync peak average power of the AM-VSB television signal. The range of power ratios occur as a result of different TV scenes used in the tests and different FM-signal frequency deviations used. All tests were performed using 525 line, system M, color-television signals.

Barnes, S. P.; Miller, E. F.

1978-01-01

175

Development of an Ion Beam Probe System for Potential Measurement in the Low Aspect-Ratio Torus Experiment Device  

NASA Astrophysics Data System (ADS)

To investigate confinement and transport characteristics in the low aspect-ratio torus plasmas which are produced and maintained solely by electron Bernstein waves in the LATE device, we are developing an ion beam probe system for potential measurement. After some component tests, the injection and the detection beam lines are installed on LATE, and the ion beams are injected in vacuum with the toroidal field, where the beam positions and profiles are observed by matrix plates detectors. It is confirmed that the beam positions are controlled by the sweeper and the deflector voltages correctly. However, the beam spreads in the toroidal direction widely and focussing of the beam is necessary. The basic design of the energy analyzer is completed to detect a potential difference of ?1 V.

Tanaka, Hitoshi; Omi, Shota; Katsuma, Jun; Yamamoto, Yurie; Uchida, Masaki; Maekawa, Takashi; Iguchi, Harukazu

176

Scaling of volume to surface ratio and doubling time in growing unicellular organisms: Do cells appear quantum-mechanical systems?  

NASA Astrophysics Data System (ADS)

The scaling of physical and biological characteristics of the living organisms is a basic method for searching of new biophysical laws. In series of previous studies the author showed that in Poikilotherms, Mammals and Aves, the volume to surface ratio V×S-1 (m) of organisms is proportional to their generation time Tgt(s) via growth rate v (m s-1): V×S-1 = vgr×Tr. The power and the correlation coefficients are near to 1.0. Aim of this study is: i) to prove with experimental data the validity of the above equation for Unicellular organisms and ii) to show that perhaps, the cells are quantum-mechanical systems. The data for body mass M (kg), density ? (kg/m3), minimum and maximum doubling time Tdt (s) for 50 unicellular organisms are assembled from scientific sources, and the computer program `Statistics' is used for calculations. In result i) the analytical relationship from type: V×S-1 = 4.46?10-11×Tdt was found, where vgr = 4.46×10-11 m/s and ii) it is shown that the products between cell mass M, cell length expressed by V/S ratio and growth rate vgr satisfied the Heisenberg uncertainty principle i.e. the inequalities V/S×M×vgr>h/2? and Tdt×M×vgr2>h/2? are valid, where h= 6.626×10-34 J?s is the Planck constant. This rise the question: do cells appear quantum-mechanical systems?

Atanasov, Atanas Todorov

2014-10-01

177

Spatial changes in carbon and nitrogen stable isotope ratios of sludge and associated organisms in a biological sewage treatment system.  

PubMed

Carbon and nitrogen stable isotope ratios (?(13)C and ?(15)N) have been utilized as powerful tools for tracing energy or material flows within food webs in a range of environmental studies. However, the techniques have rarely been applied to the study of biological wastewater treatment technologies. We report on the spatial changes in ?(13)C and ?(15)N in sludge and its associated biotic community in a wastewater treatment system. This system consisted of an upflow anaerobic sludge blanket (UASB) and a down-flow hanging sponge (DHS) which is a novel type of trickling filter. The results showed clear spatial changes in the ?(13)C and ?(15)N of suspended solids (SS), retained sludge, and macrofauna (oligochaetes and fly larvae) in the system. The ?(13)C and ?(15)N was used as a natural tracer to determine the SS dynamic throughout the system. The results imply that SS in the DHS effluent was mainly eluted from the retained sludge in the lower section of the DHS reactor. The ?(15)N of the retained sludge in the DHS reactor increased drastically from the inlet towards to the outlet, from -0.7‰ to 10.3‰. This phenomenon may be attributed to nitrogen conversion processes (i.e. nitrification and denitrification). The ?(15)N of oligochaetes also increased from the inlet to the outlet, which corresponded well to that of the retained sludge. Thus, the ?(15)N of the oligochaetes might simply mirror the ?(15)N of the retained sludge. On the other hand, the ?(13)C and ?(15)N of sympatric fly larvae differed from those of the oligochaetes sampled, indicating dietary differences between the taxa. Therefore ?(13)C and ?(15)N reflected both treatment and dietary characteristics. We concluded that ?(13)C and ?(15)N values are potentially useful as alternative indicators for investigating microbial ecosystems and treatment characteristics of biological wastewater treatment systems. PMID:25462745

Onodera, Takashi; Kanaya, Gen; Syutsubo, Kazuaki; Miyaoka, Yuma; Hatamoto, Masashi; Yamaguchi, Takashi

2014-10-16

178

Behavior of aircraft antiskid breaking systems on dry and wet runway surfaces: A slip-ratio-controlled system with ground speed reference from unbraked nose wheel  

NASA Technical Reports Server (NTRS)

An experimental investigation was conducted at the Langley aircraft landing loads and traction facility to study the braking and cornering response of a slip ratio controlled aircraft antiskid braking system with ground speed reference derived from an unbraked nose wheel. The investigation, conducted on dry and wet runway surfaces, utilized one main gear wheel, brake, and tire assembly of a DC-9 series 10 airplane. During maximum braking, the average ratio of the drag force friction coefficient developed by the antiskid system to the maximum drag force friction coefficient available was higher on the dry surface than on damp and flooded surfaces, and was reduced with lighter vertical loads, higher yaw angles, and when new tire treads were replaced by worn treads. Similarly, the average ratio of side force friction coefficient developed by the tire under antiskid control to the maximum side force friction coefficient available to a freely rolling yawed tire decreased with increasing yaw angle, generally increased with ground speed, and decreased when tires with new treads were replaced by those with worn treads.

Tanner, J. A.; Stubbs, S. M.

1977-01-01

179

A Tropical Lake Breeze System : The Effect on Surface NO, NO2, O3, and CO2 Mixing Ratios  

NASA Astrophysics Data System (ADS)

During the Cooperative LBA Airborne Regional Experiment 2001 (CLAIRE2001, July 2001), we investigated diel variations of nitric oxide (NO), nitrogen dioxide (NO_2), ozone (O_3) and carbon dioxide (CO_2) mixing ratios at Balbina Limnological Station (01^o55'994''S, 59^o28'071''W, Amazonia,Brazil). We applied sensitive and species-specific chemiluminescence (NO, NO_2, O_3) and NDIR (CO_2) analysers to record ambient mixing ratios on 1 min intervals. Simultaneously, we extensively monitored (micro-)meteorological qauntities (air temperature, relative humidity, wind speed and -direction, thermal stratification, rainfall intensity, soil temperatures and moisture, as well as radiation fluxes (global, net, short wave, NO_2 photolysis, and photosynthetic active)). Balbina Limnological Station is located just a few hundred meters south of a 2.360 km^2 hydroelectric power dam (Usina Hidrelétrica de Balbina) and about 100m north from the edge of a primary rainforest. Marked differences in surface albedo and heat storage capacity generate a local wind system, the lake breeze, which advects air from the dam (09:00 to 15:00 local) and from the rainforest (18:00 to 06:00 local), respectively. Generally, we observed marked diel variations of NO, NO_2, O_3, and CO_2 (high/low levels during night/day) and O_3 (low/high levels during night/day). Especially in the tropics, this behaviour is usually related to (a) accumulation of soil emissions (NO, CO_2), chemical reactions (NO, from NO_2-O_3 reaction) and surface destruction (O_3) in a shallow and strong nocturnal boundary layer inversion, and (b) to soil emission (NO), photochemical reactions (NO-NO_2-O_3), dry deposition/plant uptake (NO_2, O_3, and CO_2) and strong turbulent vertical mixing in the daytime mixed layer. However, under the specific conditions of the lake breeze soil emission and dry deposition/ plant uptake can be neglected during daytime. Consequently, the investigation of daytime mixing ratios can be confined to the influence of photochemical reactions (photo-stationarity) and boundary layer mixing.

Lima Moura, M. A.; Eça D'Almeida Rocha, C. H.; Trebs, I.; Andreae, M. O.; Meixner, F. X.

2003-04-01

180

Performance of the wet oxidation unit of the HPLC isotope ratio mass spectrometry system for halogenated compounds.  

PubMed

The performance of liquid chromatography-isotope ratio mass spectrometry (LC-IRMS) for polar halogenated compounds was evaluated. Oxidation capacity of the system was tested with halogenated acetic acids and halogenated aromatic compounds. Acetic acid (AA) was selected as a reference compound for complete oxidation and compared on the molar basis to the oxidation of other analytes. The isotope values were proofed with calibrated ?(13)C values obtained with an elemental analyzer (EA). Correct isotope values were obtained for mono- and dichlorinated, fluorinated, and tribrominated acetic acids and also for aniline, phenol, benzene, bromobenzene, chlorobenzene, 1,2-dichlorobenzene, 2,4,6-trichlorophenol, pentafluorophenol, and nitrobenzene. Incomplete oxidation of trichloroacetic acid (TCA) and trifluoroacetic acid (TFA) resulted in lower recovery compared to AA (37% and 24%, respectively) and in isotopic shift compared to values obtained with EA (TCA ??(13)C(EA/LC-IRMS) = 8.8‰, TFA ??(13)C(EA/LC-IRMS) = 6.0‰). Improvement of oxidation by longer reaction time in the reactor and increase in the concentration of sulfate radicals did not lead to complete combustion of TCA and TFA needed for ?(13)C analysis. To the best of our knowledge, this is the first time such highly chlorinated compounds were studied with the LC-IRMS system. This work provides information for method development of LC-IRMS methods for halogenated contaminants that are known as potential threats to public health and the environment. PMID:24975492

Gilevska, Tetyana; Gehre, Matthias; Richnow, Hans Hermann

2014-08-01

181

System for detection of air/fuel ratio in IC engine by using oxygen sensor operated with supply of current  

SciTech Connect

An air/fuel ratio detection system is disclosed for an IC engine, using an oxygen sensor element of the concentration cell type which has a laminate of a measurement electrode layer exposed to the exhaust gas, a porous layer of oxygen ion conductive solid electrolyte and a reference electrode layer and requires the supply of a small DC current thereto to produce a reference oxygen partial pressure at the reference electrode by a balance between migration of oxygen ions to the reference electrode and diffusion of oxygen molecules therefrom. To prevent excessive rise in the reference oxygen partial pressure even when the engine continues to discharge exhaust gas high in the content of oxygen, the detection system has a control circuit which controls the intensity and flow direction of the current for the sensor element with reference to a voltage which is produced by adding a definite voltage to, or subtracting the definite voltage from, the sensor output voltage depending on the level of oxygen content in the exhaust gas indicated by the sensor output voltage and smoothing the voltage resulting from the addition or subtraction.

Kitahara, T.; Sone, K.; Uchida, M.

1984-04-03

182

System for feedback control of air/fuel ratio in IC engine with means to control current supply to oxygen sensor  

SciTech Connect

An air/fuel ratio control system is disclosed including an oxygen sensor disposed in the exhaust gas to provide a feedback signal. The oxygen sensor is of the solid electrolyte concentration cell type having a heater and is operated with supply of a DC current to the concentration cell to maintain a reference oxygen partial pressure therein. A fuel feed control circuit in this system shifts its closed-looped control function to open-loop aiming at a lower air/fuel ratio if the output of the oxygen sensor continues to indicate that actual air/fuel ratio remains on one side of the intended air/fuel ratio due to breaking of the heater. To prevent the engine from stalling or operating unstably due to excessive increase in the air/fuel ratio before the shift to open-loop control, the system includes means for detecting breaking of the heater and immediately interrupting the current supply to the concentration cell in the oxygen sensor thereby forcing the sensor to put out an output which is indicative of a very high air/fuel ratio and, hence, causes the control circuit to lower the air/fuel ratio before the interruption of the closed-loop control.

Sone, K.; Kitahara, T.

1984-02-07

183

Polaradiometric pyrometer in which the parallel and perpendicular components of radiation reflected from an unpolarized light source are equalized with the thermal radiation emitted from a measured object to determine its true temperature  

NASA Technical Reports Server (NTRS)

A radiation pyrometer for measuring the true temperature of a body is provided by detecting and measuring thermal radiation from the body based on the principle that the effects of angular emission I(sub 1) and reflection I(sub 2) on the polarization states p and s of radiation are complementary such that upon detecting the combined partial polarization state components I(sub p) =I(sub 1p) + I(sub 2p) and I(sub s)=I(sub 1s) + I(sub 2s) and adjusting the intensity of the variable radiation source of the reflected radiation I(sub 2) until the combined partial radiation components I(sub p) and I(sub s) are equal, the effects of emissivity as well as diffusivity of the surface of the body are eliminated, thus obviating the need for any post processing of brightness temperature data.

Abtahi, Ali A. (Inventor)

1995-01-01

184

New microangiography system development providing improved small vessel imaging, increased contrast-to-noise ratios, and multiview 3D reconstructions  

NASA Astrophysics Data System (ADS)

A new microangiographic system (MA) integrated into a c-arm gantry has been developed allowing precise placement of a MA at the exact same angle as the standard x-ray image intensifier (II) with unchanged source and object position. The MA can also be arbitrarily moved about the object and easily moved into the field of view (FOV) in front of the lower resolution II when higher resolution angiographic sequences are needed. The benefits of this new system are illustrated in a neurovascular study, where a rabbit is injected with contrast media for varying oblique angles. Digital subtraction angiographic (DSA) images were obtained and compared using both the MA and II detectors for the same projection view. Vessels imaged with the MA appear sharper with smaller vessels visualized. Visualization of ~100 ?m vessels was possible with the MA whereas not with the II. Further, the MA could better resolve vessel overlap. Contrast to noise ratios (CNR) were calculated for vessels of varying sizes for the MA versus the II and were found to be similar for large vessels, approximately double for medium vessels, and infinitely better for the smallest vessels. In addition, a 3D reconstruction of selected vessel segments was performed, using multiple (three) projections at oblique angles, for each detector. This new MA/II integrated system should lead to improved diagnosis and image guidance of neurovascular interventions by enabling initial guidance with the low resolution large FOV II combined with use of the high resolution MA during critical parts of diagnostic and interventional procedures.

Kuhls, Andrew T.; Patel, Vikas; Ionita, Ciprian; Noël, Peter B.; Walczak, Alan M.; Rangwala, Hussain S.; Hoffmann, Kenneth R.; Rudin, Stephen

2006-03-01

185

The Alfalfa “Almost Darks” Campaign: Pilot VLA HI Observations of Five High Mass-To-Light Ratio Systems  

NASA Astrophysics Data System (ADS)

We present new Very Large Array (VLA) H i spectral line imaging of five sources discovered by the ALFALFA extragalactic survey. These targets are drawn from a larger sample of systems that were not uniquely identified with optical counterparts during ALFALFA processing, and as such have unusually high H i mass to light ratios. The candidate “Almost Dark” objects fall into four broad categories: (1) objects with nearby H i neighbors that are likely of tidal origin; (2) objects that appear to be part of a system of multiple H i sources, but which may not be tidal in origin; (3) objects isolated from nearby ALFALFA H i detections, but located near a gas-poor early type galaxy; (4) apparently isolated sources, with no object of coincident redshift within ˜400 kpc. Roughly 75% of the 200 objects without identified counterparts in the ?.40 database (Haynes et al. 2011) fall into category 1 (likely tidal), and were not considered for synthesis follow-up observations. The pilot sample presented here (AGC193953, AGC208602, AGC208399, AGC226178, and AGC233638) contains the first five sources observed as part of a larger effort to characterize H i sources with no readily identifiable optical counterpart at single dish resolution (3.?5). These objects span a range of H i mass [7.41 < log(MHi ) < 9.51] and H i mass to B-band luminosity ratios (3 < MHi /LB < 9). We compare the H i total intensity and velocity fields to optical imaging drawn from the Sloan Digital Sky Survey and to ultraviolet imaging drawn from archival GALEX observations. Four of the sources with uncertain or no optical counterpart in the ALFALFA data are identified with low surface brightness optical counterparts in Sloan Digital Sky Survey imaging when compared with VLA H i intensity maps, and appear to be galaxies with clear signs of ordered rotation in the H i velocity fields. Three of these are detected in far-ultraviolet GALEX images, a likely indication of star formation within the last few hundred Myrs. One source (AGC208602) is likely tidal in nature, associated with the NGC 3370 group. Consistent with previous efforts, we find no “dark galaxies” in this limited sample. However, the present observations do reveal complex sources with suppressed star formation, highlighting both the observational difficulties and the necessity of synthesis follow-up observations to understand these extreme objects.

Cannon, John M.; Martinkus, Charlotte P.; Leisman, Lukas; Haynes, Martha P.; Adams, Elizabeth A. K.; Giovanelli, Riccardo; Hallenbeck, Gregory; Janowiecki, Steven; Jones, Michael; Józsa, Gyula I. G.; Koopmann, Rebecca A.; Nichols, Nathan; Papastergis, Emmanouil; Rhode, Katherine L.; Salzer, John J.; Troischt, Parker

2015-02-01

186

Quenching Effect, Signal to Noise, Contrast to Noise Ratios on Scintillator Screens for Proton Beam Dosimetry System  

NASA Astrophysics Data System (ADS)

There has been dosimetry using scintillator screen for proton quality assurance recently. To develop a proton beam dosimetry system using scintillator, we evaluated the dosimetric properties and imaging quality for three kinds of scintillator screens. Proton beam ranges of 6, 9, and 12 g/cm2 were determined in a water phantom using an ion chamber. Beam current was optimized about each scintillator screen at proton beam ranges of 6, 9, and 12 g/cm2. Dose rate was in beam condition of proton treatment. For comparison of the dosimetric properties, the quenching correction factors and standard deviations for the scintillator screens (C6H6, Gd2O2S:Tb, and Gd2O2S) were obtained using the relation between the light yield (scintillator-relative output) and the dose distribution (diode-relative output). The image qualities for the scintillator screens were compared, using the signal-to-noise ratio (SNR) and the contrast-to-noise ratio (CNR), in consideration of the physical properties of the scintillator materials. After correction of the quenching effect, the correction factor for scintillator screen Gd2O2S:Tb was the lowest, at 0.004 g/(cm2 MeV). The standard deviations of the difference between the yields measured by the scintillator screens and the diode detector averaged 1, 1.3, and 1.3, respectively, at all of the ranges from origin to the peak position. The dosimetric properties of scintillator screens were no large difference. The SNRs of the scintillator screens (C6H6, Gd2O2S:Tb, and Gd2O2S) averaged 28.67, 40.18, and 24.56, respectively, at all ranges. The CNRs of the scintillator screens (C6H6, Gd2O2S:Tb, and Gd2O2S) averaged 0.44, 0.33, and 0.42, respectively, at all ranges. The highest SNR and the lowest CNR of scintillator screen Gd2O2S:Tb were more excellent than those of the other scintillator screens. We evaluated the dosimetric properties in terms of the quenching-effect correction factors, standard deviations image qualities in terms of SNR and CNR about scintillator screens. The correction factor and standard deviation for scintillator screens made no large difference. Scintillator screen Gd2O2S:Tb had the highest value of SNR and the lowest value of CNR, and accordingly was considered to be best in proton beam imaging quality.

Kim, Seonkyu; Byeong Lee, Se; Yoo, Seung Hoon; Cho, Sungkoo; Kim, Dong Wook; Shin, Dongho; Park, Sung Yong; Kim, Chan Hyeong; Lee, Sang Hoon

2012-04-01

187

40 CFR 141.534 - How does my system use this data to calculate an inactivation ratio?  

Code of Federal Regulations, 2010 CFR

... (a) Uses only one point of disinfectant application (1) One inactivation...inactivation ratios, between the point of disinfectant application and a point before or... (b) Uses more than one point of disinfectant application before the first...

2010-07-01

188

Qualitative tissue differentiation by analysing the intensity ratios of atomic emission lines using laser induced breakdown spectroscopy (LIBS): prospects for a feedback mechanism for surgical laser systems.  

PubMed

The research work presented in this paper focuses on qualitative tissue differentiation by monitoring the intensity ratios of atomic emissions using 'Laser Induced Breakdown Spectroscopy' (LIBS) on the plasma plume created during laser tissue ablation. The background of this study is to establish a real time feedback control mechanism for clinical laser surgery systems during the laser ablation process. Ex-vivo domestic pig tissue samples (muscle, fat, nerve and skin) were used in this experiment. Atomic emission intensity ratios were analyzed to find a characteristic spectral line for each tissue. The results showed characteristic elemental emission intensity ratios for the respective tissues. The spectral lines and intensity ratios of these specific elements varied among the different tissue types. The main goal of this study is to qualitatively and precisely identify different tissue types for tissue specific laser surgery. (© 2013 WILEY-VCH Verlag GmbH &Co. KGaA, Weinheim). PMID:24376030

Kanawade, Rajesh; Mahari, Fanuel; Klämpfl, Florian; Rohde, Maximilian; Knipfer, Christian; Tangermann-Gerk, Katja; Adler, Werner; Schmidt, Michael; Stelzle, Florian

2015-01-01

189

Fuel Cycle System Analysis Implications of Sodium-Cooled Metal-Fueled Fast Reactor Transuranic Conversion Ratio  

SciTech Connect

If advanced fuel cycles are to include a large number of fast reactors (FRs), what should be the transuranic (TRU) conversion ratio (CR)? The nuclear energy era started with the assumption that they should be breeder reactors (CR > 1), but the full range of possible CRs eventually received attention. For example, during the recent U.S. Global Nuclear Energy Partnership program, the proposal was burner reactors (CR < 1). Yet, more recently, Massachusetts Institute of Technology's "Future of the Nuclear Fuel Cycle" proposed CR [approximately] 1. Meanwhile, the French company EDF remains focused on breeders. At least one of the reasons for the differences of approach is different fuel cycle objectives. To clarify matters, this paper analyzes the impact of TRU CR on many parameters relevant to fuel cycle systems and therefore spans a broad range of topic areas. The analyses are based on a FR physics parameter scan of TRU CR from 0 to [approximately]1.8 in a sodium-cooled metal-fueled FR (SMFR), in which the fuel from uranium-oxide-fueled light water reactors (LWRs) is recycled directly to FRs and FRs displace LWRs in the fleet. In this instance, the FRs are sodium cooled and metal fueled. Generally, it is assumed that all TRU elements are recycled, which maximizes uranium ore utilization for a given TRU CR and waste radiotoxicity reduction and is consistent with the assumption of used metal fuel separated by electrochemical means. In these analyses, the fuel burnup was constrained by imposing a neutron fluence limit to fuel cladding to the same constant value. This paper first presents static, time-independent measures of performance for the LWR [right arrow] FR fuel cycle, including mass, heat, gamma emission, radiotoxicity, and the two figures of merit for materials for weapon attractiveness developed by C. Bathke et al. No new fuel cycle will achieve a static equilibrium in the foreseeable future. Therefore, additional analyses are shown with dynamic, time-dependent measures of performance including uranium usage, TRU inventory, and radiotoxicity to evaluate the complex impacts of transition from the current uranium-fueled LWR system, and other more realistic impacts that may not be intuited from the time-independent steady-state conditions of the end-state fuel cycle. These analyses were performed using the Verifiable Fuel Cycle Simulation Model VISION. Compared with static calculations, dynamic results paint a different picture of option space and the urgency of starting a FR fleet. For example, in a static analysis, there is a sharp increase in uranium utilization as CR exceeds 1.0 (burner versus breeder). However, in dynamic analyses that examine uranium use over the next 1 to 2 centuries, behavior as CR crosses the 1.0 threshold is smooth, and other parameters such as the time required outside of reactors to recycle fuel become important. Overall, we find that there is no unambiguously superior value of TRU CR; preferences depend on the relative importance of different fuel cycle system objectives.

Steven J. Piet; Edward A. Hoffman; Samuel E. Bays; Gretchen E. Matthern; Jacob J. Jacobson; Ryan Clement; David W. Gerts

2013-03-01

190

Your fate is in your hands? Handedness, digit ratio (2D:4D), and selection to a national talent development system.  

PubMed

Over the past decade a small evidence base has highlighted the potential importance of seemingly innocuous variables related to one's hands, such as hand dominance and the relative length of the second and fourth digits (2D:4D ratio), to success in sport. This study compared 2D:4D digit ratio and handedness among handball players selected to advance in a national talent development system with those not selected. Participants included 480 youth handball players (240 females and 240 males) being considered as part of the talent selection programme for the German Youth National team. Hand dominance and digit ratio were compared to age-matched control data using standard t-tests. There was a greater proportion of left-handers compared to the normal population in males but not in females. There was also a lower digit ratio in both females and males. However, there were no differences between those selected for the next stage of talent development and those not selected on either handedness or digit ratio. These results add support for general effects for both digit ratio and handedness in elite handball; however, these factors seem inadequate to explain talent selection decisions at this level. PMID:23444944

Baker, Joseph; Kungl, Ann-Marie; Pabst, Jan; Strauß, Bernd; Büsch, Dirk; Schorer, Jörg

2013-01-01

191

ENRICHMENT OF THE DUST-TO-GAS MASS RATIO IN BONDI/JEANS ACCRETION/CLOUD SYSTEMS DUE TO UNEQUAL CHANGES IN DUST AND GAS INCOMING VELOCITIES  

E-print Network

ENRICHMENT OF THE DUST-TO-GAS MASS RATIO IN BONDI/JEANS ACCRETION/CLOUD SYSTEMS DUE TO UNEQUAL CHANGES IN DUST AND GAS INCOMING VELOCITIES P. M. Bellan Applied Physics, California Institute. It is shown that high-velocity dust impinging on this cloud will tend to pile up due to having a different

Bellan, Paul M.

192

A High-precision Measurement System for Carbon and Hydrogen Isotopic Ratios of Atmospheric Methane and Its Application to Air Samples Collected in the Western Pacific Region  

Microsoft Academic Search

In order to study temporal and spatial variations of atmospheric CH4 quantitatively, we originally improved a measurement system for carbon and hydrogen isotopic ratios (?13C and ?D) of CH4 to attain high-precision measurements. By analyzing 100 mL aliquots of an ambient air sample, the precision of our system is 0.080‰ for ?13C and 2.20‰ for ?D(1?), which are one of

Taku UMEZAWA; Shuji AOKI; Takakiyo NAKAZAWA; Shinji MORIMOTO

2009-01-01

193

Continuous shipboard sampling system for determination of triple oxygen isotopes and O2/Ar ratio by dual-inlet mass spectrometry.  

PubMed

A continuous shipboard sampling system was developed for the determination of the isotopic composition of the triple oxygen isotopes and oxygen to argon (O(2)/Ar) ratios in dissolved air. In this system, dissolved air is separated by a hollow fiber membrane degassing module. This system collects dissolved air quantitatively and rapidly. The sample flow rate through the membrane is critical for the fractionation of the oxygen isotopes and the O(2)/Ar ratio and should be < 2 mL/min. Fractionation of oxygen between the liquid and gas phase of the air-saturated water was found to be similar to that of earlier reports. The advantages of this method over existing techniques include rapid collection of samples (30 min/sample), high efficiency in extraction of gases from the liquid phase, and the lack of a sample preparation step (e.g. degassing). PMID:17078103

Sarma, V V S S; Abe, O; Yoshida, N; Saino, T

2006-01-01

194

A dual-mode generalized likelihood ratio approach to self-reorganizing digital flight control system design  

NASA Technical Reports Server (NTRS)

The research is reported on the problems of failure detection and reliable system design for digital aircraft control systems. Failure modes, cross detection probability, wrong time detection, application of performance tools, and the GLR computer package are discussed.

Bueno, R.; Chow, E.; Gershwin, S. B.; Willsky, A. S.

1975-01-01

195

40 CFR 141.534 - How does my system use this data to calculate an inactivation ratio?  

Code of Federal Regulations, 2011 CFR

...ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) WATER PROGRAMS (CONTINUED) NATIONAL PRIMARY DRINKING WATER REGULATIONS Enhanced Filtration and Disinfection-Systems Serving Fewer Than 10,000 People Disinfection Profile § 141.534 How does my system...

2011-07-01

196

40 CFR 141.536 - My system has developed an inactivation ratio; what must we do now?  

Code of Federal Regulations, 2010 CFR

...ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) WATER PROGRAMS (CONTINUED) NATIONAL PRIMARY DRINKING WATER REGULATIONS Enhanced Filtration and Disinfection-Systems Serving Fewer Than 10,000 People Disinfection Profile § 141.536 My system has...

2010-07-01

197

40 CFR 141.536 - My system has developed an inactivation ratio; what must we do now?  

Code of Federal Regulations, 2011 CFR

...ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) WATER PROGRAMS (CONTINUED) NATIONAL PRIMARY DRINKING WATER REGULATIONS Enhanced Filtration and Disinfection-Systems Serving Fewer Than 10,000 People Disinfection Profile § 141.536 My system has...

2011-07-01

198

Tests of variable-band multilayers designed for investigating optimal signal-to-noise vs artifact signal ratios in Dual-Energy Digital Subtraction Angiography (DDSA) imaging systems  

SciTech Connect

In recent work, various design techniques were applied to investigate the feasibility of controlling the bandwidth and bandshape profiles of tungsten/boron-carbon (W/B{sub 4}C) and tungsten/silicon (W/Si) multilayers for optimizing their performance in synchrotron radiation based angiographical imaging systems at 33 keV. Varied parameters included alternative spacing geometries, material thickness ratios, and numbers of layer pairs. Planar optics with nominal design reflectivities of 30%--94% and bandwidths ranging from 0.6%--10% were designed at the Stanford Radiation Laboratory, fabricated by the Ovonic Synthetic Materials Company, and characterized on Beam Line 4-3 at the Stanford Synchrotron Radiation Laboratory, in this paper we report selected results of these tests and review the possible use of the multilayers for determining optimal signal to noise vs. artifact signal ratios in practical Dual-Energy Digital Subtraction Angiography systems.

Boyers, D.; Ho, A.; Li, Q.; Piestrup, M. [Adelphi Technology, Inc., Palo Alto, CA (United States); Rice, M.; Tatchyn, R. [Stanford Linear Accelerator Center, Menlo Park, CA (United States)

1993-08-01

199

Band Mechanism with Nonlinear Gear Ratio for Gravity Force Balance: Design and Analysis in Total System Network  

NASA Astrophysics Data System (ADS)

The application of band mechanisms offers a wide range of possibilities in designing concepts of modern guide mechanisms. The applied belt pulleys are designed as continuous convex cam disks and allow the application of different transmission functions. A large number of transmission functions can be generated with convex curve shapes. It takes a great deal of effort to determine the correct pulley curve and is difficult for engineers without special knowledge to calculate. The syntheses process of a nonlinear band mechanism is based on the relationships between the evolute and evolvente [1]. The evolute corresponds to the pulley curve and the evolvente corresponds, for example, to the curve of the fix point of a rocker arm. By applying this method in relation with the reverse kinematics and the maintenance of total band length, allowing to generate band mechanism with required curve of transmission ratio. Beside the comments of band mechanism construction and the mathematical method of resolution—the first part of the article explains a simple four bar mechanism of couch chest the total gravity force balance with band mechanism. Therefore, the essential computing steps and limits of the solving process will be explained. With this it is possible to calculate the nonlinear transmission ratio of band mechanism with consideration of elastic band properties and inertia of bodies.

Ebert, F.; Berger, M.

200

System and method to estimate compressional to shear velocity (VP/VS) ratio in a region remote from a borehole  

DOEpatents

In some aspects of the disclosure, a method for creating three-dimensional images of non-linear properties and the compressional to shear velocity ratio in a region remote from a borehole using a conveyed logging tool is disclosed. In some aspects, the method includes arranging a first source in the borehole and generating a steered beam of elastic energy at a first frequency; arranging a second source in the borehole and generating a steerable beam of elastic energy at a second frequency, such that the steerable beam at the first frequency and the steerable beam at the second frequency intercept at a location away from the borehole; receiving at the borehole by a sensor a third elastic wave, created by a three wave mixing process, with a frequency equal to a difference between the first and second frequencies and a direction of propagation towards the borehole; determining a location of a three wave mixing region based on the arrangement of the first and second sources and on properties of the third wave signal; and creating three-dimensional images of the non-linear properties using data recorded by repeating the generating, receiving and determining at a plurality of azimuths, inclinations and longitudinal locations within the borehole. The method is additionally used to generate three dimensional images of the ratio of compressional to shear acoustic velocity of the same volume surrounding the borehole.

Vu, Cung; Nihei, Kurt T; Schmitt, Denis P; Skelt, Christopher; Johnson, Paul A; Guyer, Robert; TenCate, James A; Le Bas, Pierre-Yves

2012-10-16

201

High Resolution Imaging of the Anomalous Flux-Ratio Gravitational Lens System CLASS B2045+265: Dark Or Luminous Satellites?  

SciTech Connect

The existence of flux-ratio anomalies between fold and cusp images in galaxy-scale strong-lens systems has led to an interpretation based on the presence of a high mass-fraction of cold-dark-matter (CDM) substructures around galaxies, as predicted by numerical N-body simulations. These substructures can cause large perturbations of the image magnifications, leading to changes in the image flux ratios. The flux-ratio anomaly is particularly evident in the radio-loud quadruple gravitational lens system CLASS B2045+265. In this paper, new high-resolution radio, optical, and infrared imaging of B2045+265 is presented which sheds more light on this anomaly and its possible causes. First, deep Very Long Baseline Array observations show very compact images, possibly with a hint of a jet, but with no evidence for differential scattering or scatter broadening. Hence, the flux-ratio anomaly is unlikely to be caused by refractive scattering in either the Milky Way or the lens galaxy. Second, optical and infrared observations with the Hubble Space Telescope and through Adaptive-Optics imaging with the W. M. Keck Telescope, show a previously undiscovered object--interpreted as a (tidally disrupted) dwarf satellite based on its colors and slight extension--between the main lens galaxy and the three anomalous flux-ratio images. Third, color variations in the early-type lens galaxy indicate recent star-formation, possibly the result of secondary infall of gas-rich satellites. A population of young galaxies around the lens system could explain the previously discovered strong [O II] emission. However, spiral structure and/or normal star formation in the lens galaxy cannot be excluded. In light of these new data, we propose a lens model for the system, including the observed dwarf satellite, which reproduces all positional and flux-ratio constraints, without the need for additional CDM substructure. Although the model is peculiar in that the dwarf galaxy must be highly flattened, the model is very similar to recently proposed mass models based on high-order multipole expansions.

McKean, J.P.; Koopmans, L.V.E.; Flack, C.E.; Fassnacht, C.D.; Thompson, D.; Matthews, K.; Blandford, R.D.; Readhead, A.C.S.; Soifer, B.T.; /UC, Davis /Bonn, Max Planck

2006-11-10

202

System for feedback control of air/fuel ratio in ic engine having means for supplying controlled current to oxygen sensor  

SciTech Connect

A system for feedback control of air/fuel ratio in an internal combustion engine, utilizing an oxygen-sensitive air/fuel ratio detector disposed in an exhaust gas to provide a feedback signal is disclosed. The detector has a flat and microscopically porous solid electrolyte layer with a measurement electrode layer on one side and a reference electrode layer on the other side facing a substrate. The control system includes a current supplying circuit to force a dc current to flow in the solid electrolyte layer between the two electrode layers to cause migration of oxygen ions through the solid electrolyte layer from the measurement electrode toward the reference electrode to thereby establish a reference oxygen partial pressure at the interface between the reference electrode layer and the solid electrolyte layer. To preclude an undesirably great rise of this reference oxygen partial pressure in the case of a large increase in the amount of oxygen in the exhaust gas resulting from interruption, or great reduction, of the feed of fuel to the operating engine, the control system comprises sensor means to detect the existence of such a condition and means for temporarily decreasing the intensity of the current being supplied to the air/fuel ratio detector.

Nakagawa, T.; Okamura, K.; Sone, K.

1982-12-14

203

Denitrification and nitrous oxide to nitrous oxide plus dinitrogen ratios in the soil profile under three tillage systems  

Microsoft Academic Search

There is a growing interest in the adoption of conservation tillage systems [no-till (NT) and reduced tillage (RT)] as alternatives to conventional tillage (CT) systems. A 2-year study was conducted to investigate possible environmental consequences of three tillage systems on a 2.4-ha field located at Macdonald Research Farm, McGill University, Montreal. The soil was a sandy loam (0.5 m depth) underlain

Abdirashid A. Elmi; Chandra Madramootoo; Chantal Hamel; Aiguo Liu

2003-01-01

204

Quantum dot-based multidonor concentric FRET system and its application to biosensing using an excitation ratio.  

PubMed

A plethora of semiconductor quantum dot (QD)-based probes that rely on Förster resonance energy transfer (FRET) have been developed for the optical detection of a wide array of biological targets. To date, the vast majority of these probes have utilized one-step energy transfer between individual donor-acceptor pairs. Here, we report a new multidonor concentric FRET configuration that comprised two fluorescent dyes assembled around a central CdSeS/ZnS QD through peptide linkers. One of these dyes, either Alexa Fluor 555 (A555) or Alexa Fluor 647 (A647), served as an acceptor for both the central QD and the other coassembled dye, Alexa Fluor 488 (A488). The unresolved emission between the A488 and the QD precluded a standard analysis of FRET efficiency from quenching of donor emission intensity or decay time, instead necessitating an analysis of the two energy transfer pathways from deconvolved excitation spectra. When A647 was the terminal acceptor, both the QD-to-A647 and A488-to-A647 energy transfer pathways could be interrogated with blue light, but only the former could be interrogated with violet light. The different degrees of A647 sensitization between these two excitation wavelengths was a predictable function of the above energy transfer efficiencies and dye stoichiometry, and was exploited for quantitative bioanalysis through an excitation ratio, which is in contrast to the conventional use of an emission ratio with FRET-based probes. Detection of the activity of nanomolar concentrations of trypsin, a model protease that hydrolyzed the A488-labeled peptide linker, was demonstrated using both a fluorescence plate reader and a low-cost, compact device that used two low-power light-emitting diodes (LEDs) as excitation sources and a silicon photodiode to detect A647 emission. This multidonor concentric FRET configuration represents a new modality for ratiometric biosensing with QDs and is potentially useful for portable in vitro diagnostics. PMID:24810095

Kim, Hyungki; Ng, Cheryl Y W; Algar, W Russ

2014-05-20

205

Biodegradable in situ gelling delivery systems containing pilocarpine as new antiglaucoma formulations: effect of a mercaptoacetic acid/N-isopropylacrylamide molar ratio  

PubMed Central

Ocular drug delivery is one of the most commonly used treatment modalities in the management of glaucoma. We have recently proposed the use of gelatin and poly(N-isopropylacrylamide) (PNIPAAm) graft copolymers as biodegradable in situ forming delivery systems for the intracameral administration of antiglaucoma medications. In this study, we further investigated the influence of carrier characteristics on drug delivery performance. The carboxyl-terminated PNIPAAm samples with different molecular weights were synthesized by varying the molar ratio of mercaptoacetic acid (MAA)/N-isopropylacrylamide (NIPAAm) from 0.05 to 1.25, and were determined by end-group titration. The preparation of gelatin-g-PNIPAAm (GN) copolymers from these thermoresponsive polymers was achieved using carbodiimide chemistry. Our results showed that the carboxylic end-capped PNIPAAm of high molecular weight may lead to the lower thermal phase transition temperature and slower degradation rate of GN vehicles than its low molecular weight counterparts. With a decreasing MAA/NIPAAm molar ratio, the drug encapsulation efficiency of copolymers was increased due to fast temperature-triggered capture of pilocarpine nitrate. The degradation of the gelatin network could greatly affect the drug release profiles. All of the GN copolymeric carriers demonstrated good corneal endothelial cell and tissue compatibility. It is concluded that different types of GN-based delivery systems exhibit noticeably distinct intraocular pressure-lowering effect and miosis action, thereby reflecting the potential value of a MAA/NIPAAm molar ratio in the development of new antiglaucoma formulations. PMID:24187486

Lai, Jui-Yang

2013-01-01

206

Ratios, Proportions, Similarity  

NSDL National Science Digital Library

This is a set of four, one-page problems about the size of planets compared to earth. Learners may use ratios to compare planets within our solar system or those outside of our solar system with the earth. Options are presented so that students may learn about the MESSENGER mission to Mercury through a NASA press release or by viewing a NASA eClips video [6 min.]. This activity is part of the Space Math multi-media modules that integrate NASA press releases, NASA archival video, and mathematics problems targeted at specific math standards commonly encountered in middle school.

2014-03-19

207

K? x-ray emission characterization of 100 Hz, 15 mJ femtosecond laser system with high contrast ratio  

PubMed Central

We report K? x-ray production with a high energy (110 mJ per pulse at 800 nm before compression/15 mJ at 400 nm after compression), high repetition rate (100 Hz), and high pulse contrast (better than 10?9 at 400 nm) laser system. To develop laser-based x-ray sources for biomedical imaging requires to use high-energy and high-power ultra-fast laser system where compression is achieved under vacuum. Using this type of laser system, we demonstrate long-term stability of the x-ray yield, conversion efficiency higher than 1.5 × 10?5 with a Mo target, and the x-ray spot size close to the optical focal spot. This high-repetition K? x-ray source can be very useful for x-ray phase-contrast imaging. PMID:20052295

Serbanescu, C.; Kincaid, R.E.; Krol, A.; Kieffer, J.C.

2009-01-01

208

Evaluation of a tracer release and measurement system for the detection and quantification of air emissions using the tracer ratio method  

NASA Astrophysics Data System (ADS)

The number of oil and gas production operations is increasing as is their proximity to residential areas. These facilities have been known to emit methane and other volatile organic compounds (VOCs) to the atmosphere during the different phases of development and operation. To gain a better understanding of the types and magnitude of these emissions, accurate methods for identifying and measuring the plumes released from these sources are needed. One of the most common methods for characterization of emissions is the tracer ratio. In this method, a known amount of a tracer gas is released near the potential emission source, both the tracer and the compound(s) of interest are then measured at a location downwind of the potential emissions; and the emission rate is estimated based on the ratio of the compound of interest to the tracer at the location of the measurement. This work describes field tests conducted in an air field in Fort Collins, CO to evaluate a tracer release and detection system. Acetylene (tracer gas) and methane (emission from potential source) have been released from a custom made manifold system. A PICARRO G2203 analyzer (using cavity ring down spectroscopy) and a mobile kit A0941 have been deployed on a vehicle for the downwind measurements. The emissions are measured downwind of the source and the tracer ratio method is used to calculate the emissions of methane. The measured and calculated values have been compared. Additionally, silonite-coated canisters have been used for collection and analysis of acetylene to further validate the setup. This system has been evaluated for sensitivity, accuracy and response time through a series of controlled tracer and methane releases under various meteorological conditions. The results from these tests and error analysis for the system are presented and discussed.

Hecobian, A.; Clements, A. L.; Shonkwiler, K. B.; Williams, C. M.; Wells, B. L.; MacDonald, L. P.; Pierce, J. R.; Ham, J. M.; Collett, J. L.

2013-12-01

209

Preliminary engineering report for design of a subscale ejector/diffuser system for high expansion ratio space engine testing  

NASA Technical Reports Server (NTRS)

The design of a subscale jet engine driven ejector/diffuser system is examined. Analytical results and preliminary design drawings and plans are included. Previously developed performance prediction techniques are verified. A safety analysis is performed to determine the mechanism for detonation suppression.

Wojciechowski, C. J.; Kurzius, S. C.; Doktor, M. F.

1984-01-01

210

Ratios and Proportions  

NSDL National Science Digital Library

In this learning object from Wisc-Online, students will examine ratios and proportions. The unit's activities include defining ratios and proportions, simplifying ratios, solving problems using proportions and answering practice questions.

Blohowiak, Chad; Jensen, Douglas; Reed, Allen

2005-01-01

211

Male gametophyte development and two different DNA classes of pollen grains in Rumex acetosa L., a plant with an XX\\/XY 1 Y 2 sex chromosome system and a female-biased sex ratio  

Microsoft Academic Search

Female-biased sex ratio is an interesting phenomenon observed in Rumex acetosa, a dioecious plant with an XX\\/XY1Y2 sex chromosome system. Previous authors have suggested that the biased sex ratio in this species is conditioned not only\\u000a postzygotically (sex-differential sporophytic mortality) but also prezygotically, because the sex ratio of seeds is also female-biased,\\u000a although to a lesser extent than the sex

Magdalena B?ocka-Wandas; Elwira Sliwinska; Aleksandra Grabowska-Joachimiak; Krystyna Musial; Andrzej J. Joachimiak

2007-01-01

212

Detailed characterization of 2D and 3D scatter-to-primary ratios of various breast geometries using a dedicated CT mammotomography system  

NASA Astrophysics Data System (ADS)

With a dedicated breast CT system using a quasi-monochromatic x-ray source and flat-panel digital detector, the 2D and 3D scatter to primary ratios (SPR) of various geometric phantoms having different densities were characterized in detail. Projections were acquired using geometric and anthropomorphic breast phantoms. Each phantom was filled with 700ml of 5 different water-methanol concentrations to simulate effective boundary densities of breast compositions from 100% glandular (1.0g/cm3) to 100% fat (0.79g/cm3). Projections were acquired with and without a beam stop array. For each projection, 2D scatter was determined by cubic spline interpolating the values behind the shadow of each beam stop through the object. Scatter-corrected projections were obtained by subtracting the scatter, and the 2D SPRs were obtained as a ratio of the scatter to scatter-corrected projections. Additionally the (un)corrected data were individually iteratively reconstructed. The (un)corrected 3D volumes were subsequently subtracted, and the 3D SPRs obtained from the ratio of the scatter volume-to-scatter-corrected (or primary) volume. Results show that the 2D SPR values peak in the center of the volumes, and were overall highest for the simulated 100% glandular composition. Consequently, scatter corrected reconstructions have visibly reduced cupping regardless of the phantom geometry, as well as more accurate linear attenuation coefficients. The corresponding 3D SPRs have increased central density, which reduces radially. Not surprisingly, for both 2D and 3D SPRs there was a dependency on both phantom geometry and object density on the measured SPR values, with geometry dominating for 3D SPRs. Overall, these results indicate the need for scatter correction given different geometries and breast densities that will be encountered with 3D cone beam breast CT.

Shah, Jainil; Pachon, Jan H.; Madhav, Priti; Tornai, Martin P.

2011-03-01

213

Four-point measurements of n-and p-type two-dimensional systems fabricated with cleaved-edge overgrowth  

E-print Network

of a quantum wire.9 To date, however, transport measurements of a CEO-grown 2D hole system have not been n-type samples.10 A semi-insulating 001 substrate is overgrown with a buffer layer and 10 m conditions with a substrate pyrometer temperature Tpyr=490 °C and an As4 beam flux of PAs4 =3.3 10-5 mbar

Grayson, Matthew

214

System for feedback control of air/fuel ratio in ic engine with means to control current supply to oxygen sensor  

SciTech Connect

A system for feedback control of air/fuel ratio in an ic engine, utilizing an oxygen-sensitive device which is provided with a heater and disposed in exhaust gas to provide a feedback signal. This device has a porous solid electrolyte layer with a measurement electrode layer on the outside and a reference electrode layer on the inside facing a substrate. The control system includes a sub-system to apply a voltage to the heater and force a dc current to flow through the solid electrolyte layer to cause migration of oxygen ions therethrough to thereby establish a reference oxygen partial pressure on the inner side of the solid electrolyte layer. To prevent great changes in the reference oxygen partial pressure by the influence of the exhaust gas temperature, the sub-system comprises sensors to detect the engine operating condition and control means for gradually varying both said voltage and said current according as the detected operating condition varies. For example, the voltage and current may be varied each by using a combination of a variable resistor and a stepping motor or a combination of fixed resistances and electrically controllable switches connected respectively in parallel with the resistances.

Sone, K.

1982-12-28

215

Elucidating microbial processes in nitrate- and sulfate-reducing systems using sulfur and oxygen isotope ratios: The example of oil reservoir souring control  

NASA Astrophysics Data System (ADS)

Sulfate-reducing bacteria (SRB) are ubiquitous in anoxic environments where they couple the oxidation of organic compounds to the production of hydrogen sulfide. This can be problematic for various industries including oil production where reservoir "souring" (the generation of H 2S) requires corrective actions. Nitrate or nitrite injection into sour oil fields can promote SRB control by stimulating organotrophic nitrate- or nitrite-reducing bacteria (O-NRB) that out-compete SRB for electron donors (biocompetitive exclusion), and/or by lithotrophic nitrate- or nitrite-reducing sulfide oxidizing bacteria (NR-SOB) that remove H 2S directly. Sulfur and oxygen isotope ratios of sulfide and sulfate were monitored in batch cultures and sulfidic bioreactors to evaluate mitigation of SRB activities by nitrate or nitrite injection. Sulfate reduction in batch cultures of Desulfovibrio sp. strain Lac15 indicated typical Rayleigh-type fractionation of sulfur isotopes during bacterial sulfate reduction (BSR) with lactate, whereas oxygen isotope ratios in unreacted sulfate remained constant. Sulfur isotope fractionation in batch cultures of the NR-SOB Thiomicrospira sp. strain CVO was minimal during the oxidation of sulfide to sulfate, which had ?18O SO4 values similar to that of the water-oxygen. Treating an up-flow bioreactor with increasing doses of nitrate to eliminate sulfide resulted in changes in sulfur isotope ratios of sulfate and sulfide but very little variation in oxygen isotope ratios of sulfate. These observations were similar to results obtained from SRB-only, but different from those of NR-SOB-only pure culture control experiments. This suggests that biocompetitive exclusion of SRB took place in the nitrate-injected bioreactor. In two replicate bioreactors treated with nitrite, less pronounced sulfur isotope fractionation and a slight decrease in ?18O SO4 were observed. This indicated that NR-SOB played a minor role during dosing with low nitrite and that biocompetitive exclusion was the major process. The results demonstrate that stable isotope data can contribute unique information for understanding complex microbial processes in nitrate- and sulfate-reducing systems, and offer important information for the management of H 2S problems in oil reservoirs and elsewhere.

Hubert, Casey; Voordouw, Gerrit; Mayer, Bernhard

2009-07-01

216

High serum sCD163/sTWEAK ratio is associated with lower risk of digital ulcers but more severe skin disease in patients with systemic sclerosis  

PubMed Central

Introduction Systemic sclerosis (SSc) is an autoimmune disease characterized by chronic inflammation, vascular injury and excessive fibrosis. CD163 is a scavenger receptor which affects inflammatory response and may contribute to connective tissue remodelling. It has recently been demonstrated that CD163 can bind and neutralize the TNF-like weak inducer of apoptosis (TWEAK), a multifunctional cytokine which regulates inflammation, angiogenesis and tissue remodelling. We aimed to investigate the relationships between serum levels of soluble CD163 (sCD163) and soluble TWEAK (sTWEAK) in relation to disease manifestations in SSc patients. Methods This study included 89 patients with SSc who had not received immunosuppressive drugs or steroids for at least 6 months and 48 age- and sex-matched healthy controls (HC) from four European centres. Serum concentrations of sTWEAK and sCD163 were measured using commercially available ELISA kits. Results The mean serum concentrations of sTWEAK were comparable between SSc patients (mean +/- SD: 270 +/- 171 pg/mL) and HC (294 +/- 147pg/mL, P >0.05). Concentration of sCD163 and sCD163/sTWEAK ratio were significantly greater in SSc patients (984 +/- 420 ng/mL and 4837 +/- 3103, respectively) as compared to HC (823 +/- 331 ng/mL and 3115 +/- 1346 respectively, P <0.05 for both). High sCD163 levels and a high sCD163/sTWEAK ratio (defined as > mean +2SD of HC) were both associated with a lower risk of digital ulcers in SSc patients (OR, 95%CI: 0.09; 0.01, 0.71, and 0.17; 0.06, 0.51, respectively). Accordingly, patients without digital ulcers had a significantly higher sCD163 concentration and sCD163/sTWEAK ratio as compared to SSc patients with digital ulcers (P <0.01 for both) and HC (P <0.05 for both). A high sCD163/sTWEAK ratio, but not high sCD163 levels, was associated with greater skin involvement. Conclusions The results of our study indicate that CD163-TWEAK interactions might play a role in the pathogenesis of SSc and that CD163 may protect against the development of digital ulcers in SSc. Further studies are required to reveal whether targeting of the CD163-TWEAK pathway might be a potential strategy for treating vascular disease and/or skin fibrosis in SSc. PMID:23800379

2013-01-01

217

High ratio recirculating gas compressor  

DOEpatents

A high ratio positive displacement recirculating rotary compressor is disclosed. The compressor includes an integral heat exchanger and recirculation conduits for returning cooled, high pressure discharge gas to the compressor housing to reducing heating of the compressor and enable higher pressure ratios to be sustained. The compressor features a recirculation system which results in continuous and uninterrupted flow of recirculation gas to the compressor with no direct leakage to either the discharge port or the intake port of the compressor, resulting in a capability of higher sustained pressure ratios without overheating of the compressor.

Weinbrecht, John F. (601 Oakwood Pl., NE., Albuquerque, NM 87123)

1989-01-01

218

High ratio recirculating gas compressor  

DOEpatents

A high ratio positive displacement recirculating rotary compressor is disclosed. The compressor includes an integral heat exchanger and recirculation conduits for returning cooled, high pressure discharge gas to the compressor housing to reducing heating of the compressor and enable higher pressure ratios to be sustained. The compressor features a recirculation system which results in continuous and uninterrupted flow of recirculation gas to the compressor with no direct leakage to either the discharge port or the intake port of the compressor, resulting in a capability of higher sustained pressure ratios without overheating of the compressor. 10 figs.

Weinbrecht, J.F.

1989-08-22

219

Long-distance fiber Bragg grating sensor system with a high optical signal-to-noise ratio based on a tunable fiber ring laser configuration.  

PubMed

A novel tunable fiber ring laser configuration with a combination of bidirectional Raman amplification and dual erbium-doped fiber (EDF) amplification is proposed for realizing high optical signal-to-noise ratio (SNR), long-distance, quasi-distributed fiber Bragg grating (FBG) sensing systems with large capacities and low cost. The hybrid Raman-EDF amplification configuration arranged in the ring laser can enhance the optical SNR of FBG sensor signals significantly owing to the good combination of the high gain of the erbium-doped fiber amplifier (EDFA) and the low noise of the Raman amplification. Such a sensing system can support a large number of FBG sensors because of the use of a tunable fiber Fabry-Perot filter located within the ring laser and spatial division multiplexing for expansion of sensor channels. Experimental results show that an excellent optical SNR of approximately 60 dB has been achieved for a 50 km transmission distance with a low Raman pump power of approximately 170 mW at a wavelength of 1455 nm and a low EDFA pump power of approximately 40 mW at a wavelength of 980 nm, which is the highest optical SNR achieved so far for a 50 km long FBG sensor system, to our knowledge. PMID:16936857

Rao, Yun-Jiang; Ran, Zeng-Ling; Chen, Rong-Rui

2006-09-15

220

Material flows generated by pyromet copper smelting  

USGS Publications Warehouse

Copper production through smelting generates large volumes of material flows. As copper contained in ore becomes copper contained in concentrate to be fed into the smelting process, it leaves behind an altered landscape, sometimes mine waste, and always mill tailings. Copper concentrate, fluxing materials, fuels, oxygen, recyclables, scrap and water are inputs to the process. Dust (recycled), gases - containing carbon dioxide (CO2) (dissipated) and sulfur dioxide (SO2) (mostly collected, transformed and sold) and slag (discarded or sold) - are among the significant process outputs. This article reports estimates of the flows of these input/output materials for a particular set of smelters studied in some countries.

Goonan, T.G.

2005-01-01

221

The Golden Ratio  

ERIC Educational Resources Information Center

The Golden Ratio is sometimes called the "Golden Section" or the "Divine Proportion", in which three points: A, B, and C, divide a line in this proportion if AC/AB = AB/BC. "Donald in Mathmagicland" includes a section about the Golden Ratio and the ratios within a five-pointed star or pentagram. This article presents two computing exercises that…

Hyde, Hartley

2004-01-01

222

Bicycle Gears- Ratios  

NSDL National Science Digital Library

Students experiment with and learn about the gear ratios on a bicycleâthus enhancing their understanding of circumference of a circle, proportions, etc. Actual gear ratio would be the ratio between the front and rear sprocket, NOT between pedal and rear wheel.

2011-01-01

223

System for feedback control of air/fuel ratio in IC engine with subsystem to control current supply to oxygen sensor  

SciTech Connect

A system for feedback control of air/fuel ratio in an IC engine is disclosed, utilizing a recently developed oxygen-sensitive device which is provided with a heater and disposed in exhaust gas to provide a feedback signal. This device has a porous solid electrolyte layer with a measurement electrode layer on one side and a reference electrode on the other side facing a substrate. There is a circuit to supply a heating current to the heater and force a dc current to flow in the solid electrolyte layer to cause migration of oxygen ions through the solid electrolyte toward the reference electrode to thereby establish a reference oxygen partial pressure on the reference side of the solid electrolyte layer. To prevent lowering of this oxygen partial pressure while the engine is operated under a high-load condition and the feedback control is discontinued to feed the engine with a fuel-enriched mixture, the control system includes operating condition sensor means and switching means to interrupt the supply of the current to the heater in response to a command signal from the sensor means and, optionally, current regulating means to increase the intensity of current flowing in the solid electrolyte also in response to the command signal.

Kenji, O.; Sone, K.

1982-10-19

224

Design, fabrication and characterization of high-stroke high-aspect ratio micro electro mechanical systems deformable mirrors for adaptive optics  

NASA Astrophysics Data System (ADS)

Adaptive optic (AO) systems for next generation of extremely large telescopes (30--50 meter diameter primary mirrors) require high-stroke (10 microns), high-order (100x100) deformable mirrors at lower-cost than current technology. The required specifications are achievable with Micro Electro Mechanical Systems (MEMS) devices fabricated with high-aspect ratio processing techniques. This dissertation will review simulation results compared with displacement measurements of actuators utilizing a white-light interferometer. It will also review different actuator designs, materials and post-processing procedures fabricated in three different high-aspect ratio processes, Microfabrica's Electrochemical Fabrication (EFAB(TM)), HT-Micro's Precision Fabrication Technology (HTPF(TM)), and Innovative Micro Technologies (IMT) fabrication process. These manufacturing processes allow high-precision multilayer fabrication and their sacrificial layer thicknesses can be specified by the designer, rather than by constraints of the fabrication process. Various types of high-stroke gold actuators for AO consisting of folded springs with rectangular and circular membranes as well as X-beam actuators supported diagonally by beams were designed, simulated, fabricated, and tested individually and as part of a continuous facesheet DM system. The design, modeling and simulation of these actuators are compared to experimental measurements of their pull-in voltages, which characterizes their stiffness and maximum stroke. Vertical parallel plate ganged actuators fabricated with the EFAB(TM) process have a calculated pull-in voltage of 95V for a 600mum size device. In contrast, the pull-in voltages for the comb-drive actuators ranged from 55V for the large actuator, to 203V for the smallest actuator. Simulations and interferometer scans of actuator designs fabricated with HT-Micro's Precision Fabrication (HTPF(TM)) two wafer bonded process with different spring supports have shown the ability of the actuators to achieve displacements of 1/3 of the initial gap between the spring layer and the counter electrode. Actuators and DM displacement vs. voltage have been measured with an interferometer and the corresponding results were compared to Finite Element Analysis (FEA) simulations. Simulations and interferometer scans have shown the ability of the actuators to achieve displacements of greater than 1/3 of the initial gap. A stroke of ˜9.4mum has been achieved by a DM, thus showing that this fabrication process holds promise in the manufacturing of future MEMS DMs for the next generation of extremely large telescopes. A monolithic fabrication approach for integrating a faceplate on top of an actuator array from Innovative Micro Technologies has been investigated. This monolithic approach has the ability to deposit thicker layers (tens of micrometers) of structural and sacrificial materials than that of a surface micro machining processes. This fabrication process will allow the DMs to provide both high-stoke and high-order corrections, thus eliminating the need for a woofer-tweeter DM configuration. Both the actuator and the facesheet were fabricated monolithically in gold plated onto a thermally matched ceramic-glass substrate (WMS-15) using IMT's high-aspect ratio fabrication process.

Fernandez Rocha, Bautista

225

New microangiography system development providing improved small vessel imaging, increased contrast to noise ratios, and multi-view 3D reconstructions.  

PubMed

A new microangiographic system (MA) integrated into a c-arm gantry has been developed allowing precise placement of a MA at the exact same angle as the standard x-ray image intensifier (II) with unchanged source and object position. The MA can also be arbitrarily moved about the object and easily moved into the field of view (FOV) in front of the lower resolution II when higher resolution angiographic sequences are needed. The benefits of this new system are illustrated in a neurovascular study, where a rabbit is injected with contrast media for varying oblique angles. Digital subtraction angiographic (DSA) images were obtained and compared using both the MA and II detectors for the same projection view. Vessels imaged with the MA appear sharper with smaller vessels visualized. Visualization of ~100 ?m vessels was possible with the MA whereas not with the II. Further, the MA could better resolve vessel overlap. Contrast to noise ratios (CNR) were calculated for vessels of varying sizes for the MA versus the II and were found to be similar for large vessels, approximately double for medium vessels, and infinitely better for the smallest vessels. In addition, a 3D reconstruction of selected vessel segments was performed, using multiple (three) projections at oblique angles, for each detector. This new MA/II integrated system should lead to improved diagnosis and image guidance of neurovascular interventions by enabling initial guidance with the low resolution large FOV II combined with use of the high resolution MA during critical parts of diagnostic and interventional procedures. PMID:21311731

Kuhls, Andrew T; Patel, Vikas; Ionita, Ciprian; Noël, Peter B; Walczak, Alan M; Rangwala, Hussain S; Hoffmann, Kenneth R; Rudin, Stephen

2006-01-01

226

Separation of chemical constituents from three plant medicines by counter-current chromatography using a three-phase solvent system at a novel ratio.  

PubMed

A solvent system of n-hexane, methyl acetate, acetonitrile, and water at a novel volume ratio of 4:3:4:4 forms three layers, i.e. upper phase (UP), middle phase (MP), and lower phase (LP), with a volume ratio of 1:1.20:1.42 at room temperature (25°C). All three two-phases from this three-phase solvent system were successfully used to separate some chemical constituents from three plant medicines with counter-current chromatography (CCC). Eight coumarins (B1-B8) were obtained from petroleum ether extract of fresh roots of Angelica dahurica (Baizhi) with a stationary phase of UP and a mobile phase of LP. Six diarylheptanoids (L1-L6) were obtained from petroleum ether extract of dried rhizomes of Alpinia officinarum (Liangjiang) with a stationary phase of UP and a mobile phase of MP. Three chemical constituents (Z1-Z3) were obtained from ethyl acetate extract of fresh rhizomes of Anemarrhena asphodeloides (Zhimu) with a stationary phase of MP and a mobile phase of LP. Preparative HPLC was used for further purification if necessary. Seventeen chemical constituents were identified as oxypeucedanin hydrate (B1), byakangelicin (B2), byakangelicol (B3), bergapten (B4), oxypeucedanin (B5), imperatorin (B6), phellopterin (B7), isoimperatorin (B8), 5-hydroxy-7-(4-hydroxy-3-methoxyphenyl)-1-phenyl-3-heptanone (L1), 7-(4-hydroxy-3-methoxyphenyl)-1-phenyl-4E-en-3-heptanone (L2), 5-hydroxy-1,7-diphenyl-3-heptanone (L3), 1,7-diphenyl-4E-en-3-heptanone (L4), 5-hydroxy-1,7-diphenyl-4E,6E-dien-3-heptanone (L5), isomers of 1,7-diphenyl-3,5-heptandione and 5-hydroxy-1,7-diphenyl-4E-en-3-heptanone (L6), mangiferin (Z1), timosaponin A-III (Z2), and 2,6,4'-trihydroxy-4-methoxy-benzophenone (Z3) by means of MS, (1)H and (13)C NMR studies. Five compounds of B3, L3, L5, L6, and Z3 were isolated by CCC for the first time. PMID:25660525

Wu, Xiaoyi; Chao, Zhimao; Wang, Chun; Yu, Li

2015-03-01

227

System for feedback control of air/fuel ratio in ic engine with means to control supply of current to oxygen sensor  

SciTech Connect

A system for feedback control of air/fuel ratio in an ic engine, utilizing an oxygen-sensitive device which is provided with a heater and disposed in exhaust gas to provide a feedback signal. This device has a porous solid electrolyte layer with an outer electrode layer on one side and an inner electrode on the other side facing a substrate. There is a circuit to supply a heating current to the heater and also force a dc current to flow in the solid electrolyte layer to cause migration of oxygen ions therethrough toward the inner electrode to thereby establish a reference oxygen partial pressure on the inner side of the solid electrolyte layer. This circuit is provided with current intensity regulation means to temporarily decrease the intensity of the current flowing in the solid electrolyte layer by a predetermined value while the oxygen-sensitive device is not sufficiently heated to thereby preclude undesirable rise of the basic level of the output voltage of the oxygen-sensitive device by the effect of an increased internal resistance of the not sufficiently heated element.

Okamura, K.; Sone, K.

1982-11-16

228

Random Cross Ratios Kalle strm  

E-print Network

systems. A short background into invariant based recognition is given. The use of the result ratio, e.g. in autonomous vehicle navigation, object recognition and reconstruction from images. 1 have become increasingly popular in Computer Vision, e.g. in reconstruction and recognition algorithms

Lunds Universitet

229

Pyrolaser Operating System  

NASA Technical Reports Server (NTRS)

Software provides for control and acquisition of data from optical pyrometer. There are six individual programs in PYROLASER package. Provides quick and easy way to set up, control, and program standard Pyrolaser. Temperature and emisivity measurements either collected as if Pyrolaser in manual operating mode or displayed on real-time strip charts and stored in standard spreadsheet format for posttest analysis. Shell supplied to allow macros, which are test-specific, added to system easily. Written using Labview software for use on Macintosh-series computers running System 6.0.3 or later, Sun Sparc-series computers running Open-Windows 3.0 or MIT's X Window System (X11R4 or X11R5), and IBM PC or compatible computers running Microsoft Windows 3.1 or later.

Roberts, Floyd E., III

1994-01-01

230

Compression Ratio Adjuster  

NASA Technical Reports Server (NTRS)

New mechanism alters compression ratio of internal-combustion engine according to load so that engine operates at top fuel efficiency. Ordinary gasoline, diesel and gas engines with their fixed compression ratios are inefficient at partial load and at low-speed full load. Mechanism ensures engines operate as efficiently under these conditions as they do at highload and high speed.

Akkerman, J. W.

1982-01-01

231

Likelihood Ratio Tests  

NSDL National Science Digital Library

This page, created by Kyle Siegrist of the University of Alabama - Huntsville, introduces likelihood ratio tests by giving the Neyman-Pearson lemma and several examples. The examples include a gamma model, a binomial model, and a nonparametric model. The page concludes with a definition of the generalized likelihood ratio test.

Siegrist, Kyle

232

Inbreeding and parasite sex ratios.  

PubMed Central

The breeding system of parasitic protozoa affects the evolution of drug resistance and virulence, and is relevant to disease diagnosis and the development of chemo- and immunotherapy. A major group of protozoan parasites, the phylum Apicomplexa, that includes the aetiological agents of malaria, toxoplasmosis and coccidiosis, all have dimorphic sexual stages. The sex ratio (proportion of males produced by parasites) is predicted to depend upon the inbreeding rate, and it has been suggested that sex-ratio data offer a relatively cheap and easy method for indirectly estimating inbreeding rates. Here, we exploit a new theoretical machinery to show that there are generally valid relationships between f, Wright's coefficient of inbreeding, and sex ratio, z(*), the generality being with respect to population structure. To focus the discussion, we concentrate on malaria and show that the previously derived result, f = 1 - 2z(*), does not depend on the artificial assumptions about population structure that were previously made. Not only does this justify the use of sex ratio as an indirect measure of f, but also we argue that it may actually be preferable to measure f by measuring sex ratios, rather than by measuring departures from Hardy-Weinberg genotypic proportions both in malaria and parasites more generally. PMID:11934369

Nee, Sean; West, Stuart A; Read, Andrew F

2002-01-01

233

Use of VNIR Camera System to Estimate Lava Temperature  

NASA Astrophysics Data System (ADS)

We present initial results from using a visible and near infrared (VNIR) camera as an optical pyrometer at Kilauea Volcano, Hawai`i. The basic concept of pyrometry simply converts the color of incandescent material into a temperature and has been used on Kilauea since the earliest days of regular volcano monitoring. However, these temperatures have always been lower than expected, raising the concern that the emissivity of lava at these wavelengths was not close to a blackbody. We carefully calibrated a system that uses 3 digital cameras with wavelengths similar to the green, red, and near-infrared channels of the Landsat Enhanced Thematic Mapper plus (ETM+) and Advanced Spaceborne Thermal Emissions and Reflection Radiometer (ASTER) VNIR instruments by imaging a high-temperature blackbody. Following techniques used to estimate lava temperatures on Jupiter's moon, Io, we obtained relationships between band ratios and blackbody temperatures. The green/red ratio provides good temperature estimates for any reasonable temperature above 1000 °C, while the red/NIR is useful from about 700-1200 °C. We also observed the glow from the lava lake in Halema`uma`u as reflected and scattered from the steam plume above it. We found that the temperatures inferred from the glow are much too high (~1400 °C) from the red/NIR ratios and much too low (<700 °C) from the green/red ratios. One possible explanation is that there are variations in the emissivity of molten lava at these wavelengths. However, we also know that there are wavelength dependent scattering properties of the plume cloud that are consistent with errors in these temperature estimates. Future work examining incandescent lava without the interference of a plume will be needed to better evaluate the emissivity of lava in this wavelength range. However, we have sufficient data to demonstrate the great utility of VNIR data acquired at night for determining if a volcano is actively erupting mafic lava. We propose that further refinement of this methodology using ETM+, ASTER, and other instruments could provide a useful complement to other near-real-time thermal alert systems.

Vaughan, R.; Keszthelyi, L. P.

2012-12-01

234

Ratio and Fractions.  

ERIC Educational Resources Information Center

Findings on ratio and on fractions from a research project on strategies and errors in secondary mathematics are discussed, with typical errors described. Pupils seemed to learn rules without understanding. (MNS)

Hart, K.

1983-01-01

235

Isotope Ratio Mass Spectrometry.  

PubMed

Isotope Ratio Mass Spectrometry (IRMS) is a specialized technique used to provide information about the geographic, chemical, and biological origins of substances. The ability to determine the source of an organic substance stems from the relative isotopic abundances of the elements which comprise the material. Because the isotope ratios of elements such as carbon, hydrogen, oxygen, sulfur, and nitrogen can become locally enriched or depleted through a variety of kinetic and thermodynamic factors, measurement of the isotope ratios can be used to differentiate between samples which otherwise share identical chemical compositions. Several sample introduction methods are now available for commercial isotope ratio mass spectrometers. Combustion is most commonly used for bulk isotopic analysis, whereas gas and liquid chromatography are predominately used for the real-time isotopic analysis of specific compounds within a mixture. Here, highlights of advances in instrumentation and applications within the last three years are provided to illustrate the impact of this rapidly growing area of research. Some prominent new applications include authenticating organic food produce, ascertaining whether or not African elephants are guilty of night-time raids on farmers' crops, and linking forensic drug and soil samples from a crime scene to a suspected point of origin. For the sake of brevity, we focus this Minireview on the isotope ratio measurements of lighter-elements common to organic sources; we do not cover the equally important field of inorganic isotope ratio mass spectrometry. PMID:19173039

Muccio, Zeland; Jackson, Glen P

2009-02-01

236

HEAVY ION FUSION SCIENCE VIRTUAL NATIONAL LABORATORY2nd QUARTER 2010 MILESTONE REPORTDevelop the theory connecting pyrometer and streak camera spectrometer data to the material properties of beam heatedtargets and compare to the data  

SciTech Connect

This milestone has been accomplished. We have extended the theory that connects pyrometer and streak spectrometer data to material temperature on several fronts and have compared theory to NDCX-I experiments. For the case of NDCX-I, the data suggests that as the metallic foils are heated they break into droplets (cf. HIFS VNL Milestone Report FY 2009 Q4). Evaporation of the metallic surface will occur, but optical emission should be directly observable from the solid or liquid surface of the foil or from droplets. However, the emissivity of hot material may be changed from the cold material and interference effects will alter the spectrum emitted from small droplets. These effects have been incorporated into a theory of emission from droplets. We have measured emission using streaked spectrometry and together with theory of emission from heated droplets have inferred the temperature of a gold foil heated by the NDCX-I experiment. The intensity measured by the spectrometer is proportional to the emissivity times the blackbody intensity at the temperature of the foil or droplets. Traditionally, a functional form for the emissivity as a function of wavelength (such as a quadratic) is assumed and the three unknown emissivity parameters (for the case of a quadratic) and the temperature are obtained by minimizing the deviations from the fit. In the case of the NDCX-I experiment, two minima were obtained: at 7200 K and 2400 K. The best fit was at 7200 K. However, when the actual measured emissivity of gold was used and when the theoretical corrections for droplet interference effects were made for emission from droplets having radii in the range 0.2 to 2.0 microns, the corrected emissivity was consistent with the 2400 K value, whereas the fit emissivity at 7200 K shows no similarity to the corrected emissivity curves. Further, an estimate of the temperature obtained from beam heating is consistent with the lower value. This exercise proved to be a warning to be skeptical of assuming functional forms when they are unknown, and also represents a first success of the droplet emission theory. The thermal optical emission from a hot metal surface is polarized (for observation angles that are not normal to the surface). By observing the intensity of both polarizations at two or more observation angles the emissivity can be inferred directly, and the temperature at the surface unambiguously determined. Emission from the spolarization (where the E-field is parallel to the surface and normal to the wave vector) is generally less intense than emission from the p-polarization (E-field that is normal to the s-polarization E-field and the wave vector.) The emissivity and temperature may be inferred directly without assuming any specific functional form for the emissivity or resorting to published data tables (which usually do not apply when temperatures reach the WDM regime). We have derived the theory of polarized emission from hot metals, and consider an improved method of temperature determination that takes advantage of polarization measurements, which we call polarization pyrometry. Thus far we have successfully applied the theory to electrically heated metallic filaments, and will apply the theory to beam heated targets when chamber space constraints are removed that will make it feasible to observe the targets at multiple angles. For the case of experiments on NDCX-II, hydrodynamic expansion on a nanosecond timescale that is comparable to the heating time will result in an expanding fluid, with a strong (but finite) density and temperature gradient. Emission will be observed from positions in the foil near the critical density (where the observation photon frequency is equal to the local plasma frequency). By assuming a brightness temperature equal to the local fluid temperature at the critical frequency, a time history of the emission spectrum from an expanding foil can be synthesized from a hydrodynamic simulation of the target. We find that observations from the ultraviolet to the infrared will allow a probing of the target at dif

More, R.M.; Barnard, J. J.; Bieniosek, F.M.; Henestroza, E.; Lidia, S. M.; Ni, P. A.

2010-04-01

237

Informal uncertainty analysis (GLUE) of continuous flow simulation in a hybrid sewer system with infiltration inflow - consistency of containment ratios in calibration and validation?  

NASA Astrophysics Data System (ADS)

Monitoring of flows in sewer systems is increasingly applied to calibrate urban drainage models used for long-term simulation. However, most often models are calibrated without considering the uncertainties. The generalized likelihood uncertainty estimation (GLUE) methodology is here applied to assess parameter and flow simulation uncertainty using a simplified lumped sewer model that accounts for three separate flow contributions: wastewater, fast runoff from paved areas, and slow infiltrating water from permeable areas. Recently GLUE methodology has been critisised for generating prediction limits without statistical coherence and consistency and for the subjectivity in the choice of a threshold value to distinguish "behavioural" from "non-behavioural" parameter sets. In this paper we examine how well the GLUE methodology performs when the behavioural parameter sets deduced from a calibration period are applied to generate prediction bounds in validation periods. By retaining an increasing number of parameter sets we aim at obtaining consistency between the GLUE generated 90% prediction limits and the actual containment ratio (CR) in calibration. Due to the large uncertainties related to spatio-temporal rain variability during heavy convective rain events, flow measurement errors, possible model deficiencies as well as epistemic uncertainties, it was not possible to obtain an overall CR of more than 80%. However, the GLUE generated prediction limits still proved rather consistent, since the overall CRs obtained in calibration corresponded well with the overall CRs obtained in validation periods for all proportions of retained parameter sets evaluated. When focusing on wet and dry weather periods separately, some inconsistencies were however found between calibration and validation and we address here some of the reasons why we should not expect the coverage of the prediction limits to be identical in calibration and validation periods in real-world applications. The large uncertainties result in wide posterior parameter limits, that cannot be used for interpretation of, for example, the relative size of paved area vs. the size of infiltrating area. We should therefore try to learn from the significant discrepancies between model and observations from this study, possibly by using some form of non-stationary error correction procedure, but it seems crucial to obtain more representative rain inputs and more accurate flow observations to reduce parameter and model simulation uncertainty.

Breinholt, A.; Grum, M.; Madsen, H.; Örn Thordarson, F.; Mikkelsen, P. S.

2013-10-01

238

Geometry of operator cross ratio  

NASA Astrophysics Data System (ADS)

The operator cross ratio, which is meaningful, in particular, for the infinite-dimensional Sato Grassmannian is defined and investigated. Its homological interpretation is presented. A matrix and operator analogue of the Schwartzian differential operator is introduced and its relation to linear Hamiltonian systems and Riccati's equation is established. The aim of these constructions is application to the KP-hierarchy (the Kadomtsev-Petviashvili hierarchy).

Zelikin, M. I.

2006-02-01

239

A new action potential detector using the MTEO and its effects on spike sorting systems at low signal-to-noise ratios  

Microsoft Academic Search

This paper considers neural signal processing applied to extracellular recordings, in particular, unsupervised action potential detection at a low signal-to-noise ratio. It adopts the basic framework of the multiresolution Teager energy operator (MTEO) detector, but presents important new results including a significantly improved MTEO detector with some mathematical analyses, a new alignment technique with its effects on the whole spike

Joon Hwan Choi; Hae Kyung Jung; Taejeong Kim

2006-01-01

240

Inherent correlation between the total output cooling capacity and equipment sensible heat ratio of a direct expansion air conditioning system under variable-speed operation (XXG SMD SHR DX AC unit)  

Microsoft Academic Search

Appropriately controlling indoor air humidity at a suitable level in buildings is important. To simultaneously control both indoor air dry-bulb temperature and relative humidity requires the match between the total output cooling capacity of an A\\/C system and the total cooling load in a space served by the A\\/C system, as well as the Equipment sensible heat ratio (SHR) of

Xiangguo Xu; Liang Xia; Mingyin Chan; Shiming Deng

2010-01-01

241

Area Ratios of Quadrilaterals.  

ERIC Educational Resources Information Center

Shows that the ratio of the area of the quadrilateral formed by joining the kth points to the area of the original quadrilateral is constant whether it is convex or concave quadrilateral. Presents many geoboard or dot paper diagrams and geometrical expresssions. (YP)

Anderson, David R.; Arcidiacono, Michael J.

1989-01-01

242

The Likelihood Ratio Test  

NSDL National Science Digital Library

This module, created by Don Johnson of Rice University, provides an explanation and an example of the likelihood ratio test. Topics include: decision regions, Bayes' decision criterion, Bayes' cost, and likelihood function. The site is enhanced by Johnson's use of graphic and numerical demonstrations to better explain his points. Additionally, a PDF attachment providing an in-depth explanation is also featured.

Johnson, Don

243

Digit ratio in birds.  

PubMed

The Homeobox (Hox) genes direct the development of tetrapod digits. The expression of Hox genes may be influenced by endogenous sex steroids during development. Manning (Digit ratio. New Brunswick, NJ: Rutgers University Press, 2002) predicted that the ratio between the lengths of digits 2 (2D) and 4 (4D) should be sexually dimorphic because prenatal exposure to estrogens and androgens positively influence the lengths of 2D and 4D, respectively. We measured digits and other morphological traits of birds from three orders (Passeriformes, house sparrow, Passer domesticus; tree swallow, Tachycineta bicolor; Pscittaciformes, budgerigar, Melopsittacus undulates; Galliformes, chicken, Gallus domesticus) to test this prediction. None were sexually dimorphic for 2D:4D and there were no associations between 2D:4D and other sexually dimorphic traits. When we pooled data from all four species after we averaged right and left side digits from each individual and z-transformed the resulting digit ratios, we found that males had significantly larger 2D:4D than did females. Tetrapods appear to be sexually dimorphic for 2D:4D with 2D:4D larger in males as in some birds and reptiles and 2D:4D smaller in males as in some mammals. The differences between the reptile and mammal lineages in the directionality of 2D:4D may be related to the differences between them in chromosomal sex determination. We suggest that (a) natural selection for a perching foot in the first birds may have overridden the effects of hormones on the development of digit ratio in this group of vertebrates and (b) caution be used in making inferences about prenatal exposure to hormones and digit ratio in birds. PMID:18833568

Lombardo, Michael P; Thorpe, Patrick A; Brown, Barbara M; Sian, Katie

2008-12-01

244

Enrichment of the dust-to-gas mass ratio in Bondi/Jeans accretion/cloud systems due to unequal changes in dust and gas incoming velocities  

E-print Network

The ratio of the Bondi and Jeans lengths is used to develop a cloud-accretion model that describes both an inner Bondi-type regime where gas pressure is balanced by the gravity of a central star and an outer Jeans-type regime where gas pressure is balanced by gas self-gravity. The gas density profile provided by this model makes a smooth transition from a wind-type inner solution to a Bonnor-Ebert type outer solution. It is shown that high-velocity dust impinging on this cloud will tend to pile-up due to having a different velocity profile than gas so that the dust-to-gas ratio is substantially enriched above the 1% ISM level.

P. M. Bellan

2008-01-27

245

Seasonal changes in body size, sexual size dimorphism and sex ratio in relation to mating system in an adult odonate community  

Microsoft Academic Search

Seasonal environments impose developmental time constraints on insects which can be reflected in body size and sex ratio.\\u000a By tracking these two aspects in recently emerged adults of 10 species of an odonate community in a number of lakes, we investigated\\u000a whether (a) body size in both sexes decreased as the flight season progressed and whether this led to seasonal

Jesús Wong-Muñoz; Alex Córdoba-Aguilar; Raúl Cueva del Castillo; Martín A. Serrano-Meneses; John Payne

2011-01-01

246

What's My Ratio?  

NSDL National Science Digital Library

In this activity, students use linear measurement and calculators to investigate proportionality and determine the constant ratio between similar figures. In it, students draw a figure on centimeter graph paper, increase or decrease the size, and predict the dimensions. Then students compare the ratio of two pictures by measuring, recording their data, and discussing their findings to draw conclusions. Suggested guidelines for instruction and classroom discussion are included, as well as data collection worksheets for students, and centimeter graph paper to print. The lesson may be introduced by reading appropriate sections from "GoosebumpsâMonster Blood III" (Chapters 15 and 16) by R.L. Stine, or "The Shrinking of Treehorn" by F. Heide.

2003-01-01

247

Displacement and Velocity Ratios  

NSDL National Science Digital Library

This interactive presentation, created by James Bourassa and John Rosz for the Electromechanical Digital Library, discusses displacement and velocity ratios. Bourassa and Rosz begin by providing detailed definitions of both topics and then provide mathematical examples of each. Once this basic explanation is complete, the authors allow students to practice these theories in a set of self-correcting quiz questions. Bourassa and Rosz explain each using helpful interactive flash animations. These are not only useful in explanation, but they allow the student to more fully engage with the topic. Overall, this is a nice introduction to the physical and mathematical concepts of displacement and velocity ratios. This could be a valuable learning resource in everything from a physics to a technical education classroom.

Bourassa, James; Rosz, John

2011-04-05

248

Ratios and Proportions  

NSDL National Science Digital Library

This interactive slideshow explains the notion of ratios and proportions, how to write the, and how to find them. There are practice problems which walk visitors through each step of the process, including reducing answers to simplest terms, in which students are asked to calculate the rate of grass seed coverage per square foot and find the miles per gallon fuel use of a car. The lesson continues on to introduce proportion and work through practice problems in the same fashion.

Jensen, Douglas; Reed, Allen

2005-01-01

249

Isotope ratio of Cl NQR spin-lattice relaxation times in 1D hydrogen-bonding system of tetramethylpyrazine-chloranilic acid at high temperatures  

NASA Astrophysics Data System (ADS)

The temperature dependences of spin-lattice relaxation time T 1 of 35Cl and 37Cl NQR were studied for the co-crystal of tetramethylpyrazine (TMP) with chloranilic acid (H2ca), TMP-H2ca, in which one-dimensional hydrogen bonding is formed by alternate arrangement of TMP and H2ca. The isotope ratio 37Cl T 1 / 35Cl T 1 was determined to be 1.0 ± 0.1 above ca. 290 K where a steep decrease of spin-lattice relaxation time T 1 with increasing temperature was observed. In this temperature range it is suggested that the relaxation is originated from the slow fluctuation of electric field gradient (EFG). Beside EFG fluctuation due to the external-charge-density fluctuation, the small angle reorientation of the quantization axis triggered by a proton transfer motion between N...H-O and N-H...O hydrogen bonding states is proposed.

Asaji, Tetsuo

2013-05-01

250

Central Nervous System Effects of the Second-Generation Antihistamines Marketed in Japan -Review of Inter-Drug Differences Using the Proportional Impairment Ratio (PIR)-  

PubMed Central

Background Second-generation antihistamines (AHs) have, in general, fewer sedative effects than the first-generation. However, important inter-drug differences remain in the degree of cognitive and/or psychomotor impairment. The extent to which a particular compound causes disruption can be conveniently compared, to all other AHs, using the Proportional Impairment Ratio (PIR). Although the PIR can differentiate the relative impairment caused by individual drugs, there is no indication of the reliability of the ratios obtained. Objective To calculate the PIRs –together with 95% confidence intervals (CIs), as an index of reliability– and compare AHs currently, or soon to be, available in Japan, with respect to their intrinsic capacity to cause impairment. Methods Results from studies of cetirizine, desloratadine, ebastine, fexofenadine, levocetirizine, loratadine, mequitazine, and olopatadine were included in the PIR calculations. All data utilised came from crossover studies in healthy volunteers which were randomised and placebo and positive-internal controlled. Existing databases from studies reporting the sedative effects of AHs on objective (speed, accuracy, memory) and subjective (feeling) psychometrics were augmented, via results from suitable studies published after the previous reviews. The null value for a PIR was one. Results A total of 45 studies were finally included for this review. Of the AHs assessed, fexofenadine, ebastine, and levocetirizine showed a PIR for objective tests of 0. However, only fexofenadine (PIR?=?0.49) had an upper limit of the 95% CI of less than 1. Fexofenadine, levocetirizine, desloratadine, olopatadine, loratadine, and mequitazine all had a PIR for subjective ratings of 0, but the upper limits of the 95% CIs were all in excess of 1, although fexofenadine (PIR?=?2.57) was the lowest. Conclusions The results show that there are differences between second-generation AHs in the extent of sedation produced. However, subjective ratings indicate that patients may not necessarily be aware of this. PMID:25501360

Isomura, Tatsuya; Kono, Takeshi; Hindmarch, Ian; Kikuchi, Norimasa; Murakami, Aya; Inuzuka, Kyoko; Kawana, Seiji

2014-01-01

251

Calcium-to-Argon and Nickel-to-Argon Abundance Ratios as Tracers of the Source Region of Postflare Loop System Material  

NASA Astrophysics Data System (ADS)

Intensities of abundance diagnostic lines of Ca XV, Ca XVI, Ni XVII, Ar XIII, and Ar XV have been derived for a classic flare loop system observed during the Skylab mission. These have been used to test for photospheric or coronal origin of the flare loop material. The resulting FIP-bias factors are between 1.7 and 4.6 with a majority of the values around 4.5 indicating a source with material modified by the FIP effect. The loop system bias factors are similar to those observed in a sample of Skylab prominences, suggesting that the disrupted mass of the preflare embedded filament provided the loop system material.

Widing, K. G.; Feldman, U.

2008-03-01

252

Peak power ratio generator  

DOEpatents

A peak power ratio generator is described for measuring, in combination with a conventional power meter, the peak power level of extremely narrow pulses in the gigahertz radio frequency bands. The present invention in a preferred embodiment utilizes a tunnel diode and a back diode combination in a detector circuit as the only high speed elements. The high speed tunnel diode provides a bistable signal and serves as a memory device of the input pulses for the remaining, slower components. A hybrid digital and analog loop maintains the peak power level of a reference channel at a known amount. Thus, by measuring the average power levels of the reference signal and the source signal, the peak power level of the source signal can be determined.

Moyer, Robert D. (Albuquerque, NM)

1985-01-01

253

Trace ratio problem revisited.  

PubMed

Dimensionality reduction is an important issue in many machine learning and pattern recognition applications, and the trace ratio (TR) problem is an optimization problem involved in many dimensionality reduction algorithms. Conventionally, the solution is approximated via generalized eigenvalue decomposition due to the difficulty of the original problem. However, prior works have indicated that it is more reasonable to solve it directly than via the conventional way. In this brief, we propose a theoretical overview of the global optimum solution to the TR problem via the equivalent trace difference problem. Eigenvalue perturbation theory is introduced to derive an efficient algorithm based on the Newton-Raphson method. Theoretical issues on the convergence and efficiency of our algorithm compared with prior literature are proposed, and are further supported by extensive empirical results. PMID:19304481

Jia, Yangqing; Nie, Feiping; Zhang, Changshui

2009-04-01

254

Ratio and Proportion  

NSDL National Science Digital Library

This interactive Flash applet helps students explore concepts of ratio and proportion. It displays two containers, each with its own tap that can be set to deliver different-colored liquids in units of 1 to 10. A main tap can be set to deliver multiples of the amounts on the left- and right-hand taps. Proportion can be modelled using the drain container, which receives whatever is in the left- and right-hand containers. Users can choose the capacity of the containers, whether to hide or show the scales, and the size and visibility of the drain container. Clicking on the info button allows users to mouse over items to learn about them. This applet lends itself well for use with an interactive white board. A pdf guide to this collection of teaching applets is cataloged separately.

2006-01-01

255

Fascicular ratio: a new parameter to evaluate peripheral nerve pathology on magnetic resonance imaging: a feasibility study on a 3T MRI system.  

PubMed

The objective of the study was to define and quantitatively evaluate the fascicular ratio (FR) on magnetic resonance imaging (MRI) in patients with peripheral neuropathies compared with healthy controls. Forty control subjects (20 women, 20 men; age, 44.6?±?13.4 years) and 40 patients with peripheral neuropathy (22 women, 18 men; age, 50.3?±?10.2 years) were examined with a standard 3T MRI protocol. With customized software (with semiautomatic and automatic interface), the hypointense and hyperintense areas of the peripheral nerves corresponding to fascicular and nonfascicular tissue were examined on T1-weighted sequences. The ratio of fascicular pixels to total pixels was called FR. Correlation with FR calculated on high-resolution ultrasound was performed. The statistical analysis included the Mann-Whitney U test of controls versus patients, the receiver operating characteristic (ROC) analysis, and the subgroup analysis of patients according to etiologies of neuropathy. Intraobserver and interobserver agreement was calculated based on the evaluation made by 3 readers. Finally, a complete automatic evaluation was performed. On MRI, FRs were significantly increased in patients compared with controls (FR, 76.7?±?15.1 vs 56?±?12.3; P?

Tagliafico, Alberto S; Tagliafico, Giulio

2014-09-01

256

A signal input coil made of superconducting thin film for improved signal-to-noise ratio in a high-Tc SQUID-based ultra-low field nuclear magnetic resonance system  

NASA Astrophysics Data System (ADS)

Resonant coupling schemes are commonly used in SQUID-based ultra-low field (ULF) nuclear magnetic resonance (NMR) systems to couple the spin relaxation signals from samples to the SQUID. Generally, in NMR systems, a resonant coupling scheme is composed of two solenoid coils which are made of enamel insulated wires and a capacitor connected in series. In this work, we tried to replace the metal solenoid input coil with a planar high-Tc superconducting spiral coil to improve the signal-to-noise ratio (SNR) of the ULF NMR signal. A measurement of the free induction decay signal of water protons was performed to demonstrate the improved performance of the system. This improvement is due to the fact that the planar superconducting spiral coil possesses a higher mutual inductance with the SQUID. Therefore, it is a promising way to enhance the SNR of high-Tc SQUID-based ULF NMR/MRI systems.

Chen, Kuen-Lin; Hsu, Chin-Wei; Ku, Yue-Bai; Chen, Hsin-Hsien; Liao, Shu-Hsien; Wang, Li-Min; Horng, Herng-Er; Yang, Hong-Chang

2013-11-01

257

Low speed test of a high-bypass-ratio propulsion system with an asymmetric inlet designed for a tilt-nacelle V/STOL airplane  

NASA Technical Reports Server (NTRS)

A large scale model of a lift/cruise fan inlet designed for a tilt nacelle V/STOL airplane was tested with a high bypass ratio turbofan. Testing was conducted at low freestream velocities with inlet angles of attack ranging from 0 deg to 120 deg. The operating limits for the nacelle were found to be related to inlet boundary layer separation. Small separations originating in the inlet diffuser cause little or no performance degradation. However, at sufficiently severe freestream conditions the separation changes abruptly to a lip separation. This change is associated with a significant reduction in nacelle net thrust as well as a sharp increase in fan blade vibratory stresses. Consequently, the onset of lip separation is regarded as the nacelle operating limit. The test verified that the asymmetric inlet design will provide high performance and stable operation at the design forward speed and angle of attack conditions. At some of these, however, operation near the lower end of the design inlet airflow range is not feasible due to the occurrence of lip separation.

Syberg, J.

1978-01-01

258

Correlation of infrared reflectance ratios at 2.3 microns/1.6 micron and 1.1 micron/1.6 micron with delta O-18 values delineating fossil hydrothermal systems in the Idaho batholith  

NASA Technical Reports Server (NTRS)

Reflectance ratios from laboratory spectra and airborne multispectral images are found to be strongly correlated with delta O-18 values of granite rocks in the Idaho batholith. The correlation is largely a result of interactions between hot water and rock, which lowered the delta O-18 values of the rocks and produced secondary hydrous material. Maps of the ratio of reflectivities at 2.3 and 1.6 microns should delineate fossil hydrothermal systems and provide estimates of alteration intensity. However, hydrous minerals produced during deuteric alteration or weathering cannot be unambiguously distinguished in remotely sensed images from the products of propylitic alteration without the use of narrow-band scanners. The reflectivity at 1.6 micron is strongly correlated with rock density and may be useful in distinguishing rock types in granitic terranes.

Gillespie, A. R.; Criss, R. E.

1983-01-01

259

A Mission-Adaptive Variable Camber Flap Control System to Optimize High Lift and Cruise Lift-to-Drag Ratios of Future N+3 Transport Aircraft  

NASA Technical Reports Server (NTRS)

Boeing and NASA are conducting a joint study program to design a wing flap system that will provide mission-adaptive lift and drag performance for future transport aircraft having light-weight, flexible wings. This Variable Camber Continuous Trailing Edge Flap (VCCTEF) system offers a lighter-weight lift control system having two performance objectives: (1) an efficient high lift capability for take-off and landing, and (2) reduction in cruise drag through control of the twist shape of the flexible wing. This control system during cruise will command varying flap settings along the span of the wing in order to establish an optimum wing twist for the current gross weight and cruise flight condition, and continue to change the wing twist as the aircraft changes gross weight and cruise conditions for each mission segment. Design weight of the flap control system is being minimized through use of light-weight shape memory alloy (SMA) actuation augmented with electric actuators. The VCCTEF program is developing better lift and drag performance of flexible wing transports with the further benefits of lighter-weight actuation and less drag using the variable camber shape of the flap.

Urnes, James, Sr.; Nguyen, Nhan; Ippolito, Corey; Totah, Joseph; Trinh, Khanh; Ting, Eric

2013-01-01

260

30 CFR 36.44 - Maximum allowable fuel : air ratio.  

Code of Federal Regulations, 2010 CFR

...false Maximum allowable fuel : air ratio. 36.44...FOR PERMISSIBLE MOBILE DIESEL-POWERED TRANSPORTATION...44 Maximum allowable fuel : air ratio. (a...delivered to MSHA with the fuel-injection system adjusted by the...

2010-07-01

261

K(alpha) x-ray emission characterization of 100 Hz, 15 mJ femtosecond laser system with high contrast ratio.  

PubMed

We report K(alpha) x-ray production with a high energy (110 mJ per pulse at 800 nm before compression/15 mJ at 400 nm after compression), high repetition rate (100 Hz), and high pulse contrast (better than 10(-9) at 400 nm) laser system. To develop laser-based x-ray sources for biomedical imaging requires to use high-energy and high-power ultra-fast laser system where compression is achieved under vacuum. Using this type of laser system, we demonstrate long-term stability of the x-ray yield, conversion efficiency higher than 1.5 x 10(-5) with a Mo target, and the x-ray spot size close to the optical focal spot. This high-repetition K(alpha) x-ray source can be very useful for x-ray phase-contrast imaging. PMID:20052295

Fourmaux, S; Serbanescu, C; Kincaid, R E; Krol, A; Kieffer, J C

2008-12-12

262

Using Cl/Br ratios and other indicators to assess potential impacts on groundwater quality from septic systems: A review and examples from principal aquifers in the United States  

USGS Publications Warehouse

A detailed review was made of chemical indicators used to identify impacts from septic tanks on groundwater quality. Potential impacts from septic tank leachate on groundwater quality were assessed using the mass ratio of chloride-bromide (Cl/Br), concentrations of selected chemical constituents, and ancillary information (land use, census data, well depth, soil characteristics) for wells in principal aquifers of the United States. Chemical data were evaluated from 1848 domestic wells in 19 aquifers, 121 public-supply wells in 6 aquifers, and associated monitoring wells in four aquifers and their overlying hydrogeologic units. Based on previously reported Cl/Br ratios, statistical comparisons between targeted wells (where Cl/Br ratios range from 400 to 1100 and Cl concentrations range from 20 to 100 mg/L) and non-targeted wells indicated that shallow targeted monitoring and domestic wells (0.5. mg/L) shallow groundwater from target domestic wells, relative to non-target wells (1.5. mg/L), corresponded to significantly higher potassium, boron, chloride, dissolved organic carbon, and sulfate concentrations, which may also indicate the influence of septic-tank effluent. Impacts on groundwater quality from septic systems were most evident for the Eastern Glacial Deposits aquifer and the Northern High Plains aquifer that were associated with the number of housing units using septic tanks, high permeability of overlying sediments, mostly oxic conditions, and shallow wells. Overall, little or no influence from septic systems were found for water samples from the deeper public-supply wells.The Cl/Br ratio is a useful first-level screening tool for assessing possible septic tank influence in water from shallow wells (<20 m) with the range of 400-1100. The use of this ratio would be enhanced with information on other chloride sources, temporal variability of chloride and bromide concentrations in shallow groundwater, knowledge of septic-system age and maintenance, and the use of multiple tracers (combination of additional chemical and microbiological indicators). ?? 2010.

Katz, B.G.; Eberts, S.M.; Kauffman, L.J.

2011-01-01

263

Using Cl/Br ratios and other indicators to assess potential impacts on groundwater quality from septic systems: A review and examples from principal aquifers in the United States  

NASA Astrophysics Data System (ADS)

SummaryA detailed review was made of chemical indicators used to identify impacts from septic tanks on groundwater quality. Potential impacts from septic tank leachate on groundwater quality were assessed using the mass ratio of chloride-bromide (Cl/Br), concentrations of selected chemical constituents, and ancillary information (land use, census data, well depth, soil characteristics) for wells in principal aquifers of the United States. Chemical data were evaluated from 1848 domestic wells in 19 aquifers, 121 public-supply wells in 6 aquifers, and associated monitoring wells in four aquifers and their overlying hydrogeologic units. Based on previously reported Cl/Br ratios, statistical comparisons between targeted wells (where Cl/Br ratios range from 400 to 1100 and Cl concentrations range from 20 to 100 mg/L) and non-targeted wells indicated that shallow targeted monitoring and domestic wells (<20 m depth below land surface) had a significantly ( p < 0.05) higher median percentage of houses with septic tanks (1990 census data) than non-targeted wells. Higher ( p = 0.08) median nitrate-N concentration (3.1 mg/L) in oxic (dissolved oxygen concentrations >0.5 mg/L) shallow groundwater from target domestic wells, relative to non-target wells (1.5 mg/L), corresponded to significantly higher potassium, boron, chloride, dissolved organic carbon, and sulfate concentrations, which may also indicate the influence of septic-tank effluent. Impacts on groundwater quality from septic systems were most evident for the Eastern Glacial Deposits aquifer and the Northern High Plains aquifer that were associated with the number of housing units using septic tanks, high permeability of overlying sediments, mostly oxic conditions, and shallow wells. Overall, little or no influence from septic systems were found for water samples from the deeper public-supply wells. The Cl/Br ratio is a useful first-level screening tool for assessing possible septic tank influence in water from shallow wells (<20 m) with the range of 400-1100. The use of this ratio would be enhanced with information on other chloride sources, temporal variability of chloride and bromide concentrations in shallow groundwater, knowledge of septic-system age and maintenance, and the use of multiple tracers (combination of additional chemical and microbiological indicators).

Katz, Brian G.; Eberts, Sandra M.; Kauffman, Leon J.

2011-02-01

264

Energy Profit Ratio Compared  

SciTech Connect

We need more oil energy to take out oil under the ground. Limit resources make us consider other candidates of energy source instead of oil. Electricity shall be the main role more and more like electric vehicles and air conditioners so we should consider electricity generation ways. When we consider what kind of electric power generation is the best or suitable, we should not only power generation plant but whole process from mining to power generation. It is good way to use EPR, Energy Profit Ratio, to analysis which type is more efficient and which part is to do research and development when you see the input breakdown analysis. Electricity by the light water nuclear power plant, the hydrogen power plant and the geothermal power plant are better candidates from EPR analysis. Forecasting the world primly energy supply in 2050, it is said that the demand will be double of the demand in 2000 and the supply will not be able to satisfy the demand in 2050. We should save 30% of the demand and increase nuclear power plants 3.5 times more and recyclable energy like hydropower plants 3 times more. When the nuclear power plants are 3.5 times more then uranium peak will come and we will need breed uranium. I will analysis the EPR of FBR. Conclusion: A) the EPR of NPS in Japan is 17.4 and it is the best of all. B) Many countries will introduce new nuclear power plants rapidly may be 3.5 times in 2050. C) Uranium peak will happen around 2050. (author)

Amano, Osamu [2-11-1, Iwado Kita, Komae-shi, Tokyo 201-8511 (Japan)

2007-07-01

265

Climatic significance of isotope ratios  

Microsoft Academic Search

The hydrogen and oxygen isotope ratios of water, which can be measured by Isotope Ratio Mass Spectrometry (IRMS), exhibit climatic dependencies and are commonly exploited in hydrogeology. More generally, the overall carbon or hydrogen isotope ratios of plant organic matter, and in particular of tree-ring cellulose, have been frequently used for climatic reconstruction. However, since many physicochemical and biochemical fractionation

Gérard J. Martin; Maryvonne L. Martin

2003-01-01

266

Poisson's ratio and crustal seismology  

Microsoft Academic Search

New measurements of compressional and shear wave velocities to hydrostatic pressures of 1 GPa are summarized for 678 rocks. Emphasis was placed on obtaining high-accuracy velocity measurements, which are shown to be critical in calculating Poisson's ratios from velocities. The rocks have been divided into 29 major groups for which velocities, velocity ratios, and Poisson's ratios are presented at several

Nikolas I. Christensen

1996-01-01

267

The 238U/235U isotope ratio of the Earth and the solar system: Constrains from a gravimetrically calibrated U double spike and implications for absolute Pb-Pb ages  

NASA Astrophysics Data System (ADS)

The ratio of 238U and 235U, the two primordial U isotopes, has been assumed to be constant on Earth and in the solar system. The commonly accepted value for the 238U/235U ratio, which has been used in Pb-Pb dating for the last ~ 30 years, was 137.88. Within the last few years, it has been shown that 1) there are considerable U isotope variations (~1.3‰) within terrestrial material produced by isotope fractionation during chemical reactions [1-3] and 2) there are even larger isotope variations (at least 3.5‰) in calcium-aluminum-rich inclusions (CAIs) in meoteorites that define the currently accepted age of the solar system [4]. These findings are dramatic for geochronology, as a known 238U/235U is a requirement for Pb-Pb dating, the most precise dating technique for absolute ages. As 238U/235U variations can greatly affect the reported absolute Pb-Pb age, understanding and accurately measuring variation of the 238U/235U ratio in various materials is critical, With these new findings, the questions also arises of "How well do we know the average U isotope composition of the Earth and the solar system?" and "How accurate can absolute Pb-Pb ages be?" Our results using a gravimetrically calibrated 233U/236U double spike IRMM 3636 [5] indicate that the U standard NBL 950a, which was commonly used to define the excepted "natural" 238U/235U isotope ratio, has a slightly lower 238U/235U of 137.836 ± 0.024. This value is indistinguishable from the U isotope compositions for NBL 960 and NBL112A, which have been determined by several laboratories, also using the newly calibrated U double spike IRMM 3636 [6]. These findings provide new implications about the average U isotope composition of the Earth and the solar system. Basalts display a very tight range of U isotope variations (~0.25-0.32‰ relative to SRM 950a). Their U isotope composition is also very similar to that of chondrites [4], which however appear to show a slightly larger spread. Accepting terrestrial basalts to be the best representation of the U isotope composition of the Earth and the solar system, and the new 238U/235U for SRM 950a of 137.836, this would result in an average 238U/235U for the Earth and the solar system of ~ 137.80. The effect of a revised 238U/235U ratio on Pb-Pb ages is age dependent. It results in an age overestimation of ~0.8 Ma for the age of the solar system and up to 1.5 Ma for very young material (with bulk Earth U isotope composition). [1] Stirling, C.H., Andersen, M.B., Potter, E.-K., et al. (2007) EPSL 264, 208-225; [2] Weyer, S., Anbar, A. D., Gerdes, A., et al. (2008) GCA 72, 345-359. [3] Bopp, C.H., Lundstrom, C.C., Johnsons, T.M., Glessner, J.G. (2009) Geology 37, 611-614. [4] Brennecka, G.A., Weyer, S., Wadhwa, et al. (2010) Science, 327, p. 449. [5] Richter, S., Alonzo-Munoz, A., Eykens, R., et al. (2008) IJMS 269, 145-148. [6] Richter, S., et al. EGU meeting 2010.

Weyer, Stefan; Noordmann, Janine; Brennecka, Greg; Richter, Stephan

2010-05-01

268

Spatial and temporal infaunal dynamics of the Blanes submarine canyon-slope system (NW Mediterranean); changes in nematode standing stocks, feeding types and gender-life stage ratios  

NASA Astrophysics Data System (ADS)

Despite recent advances in the knowledge of submarine canyons ecosystems, our understanding of the faunal patterns and processes in these environments is still marginal. In this study, meiobenthic nematode communities (from 300 m to 1600 m depth) obtained in November 2003 and May 2004 at eight stations inside and outside Blanes submarine canyon were analysed for nematode standing stocks (SSs), feeding types and gender-life stage distributions. Environmental data were obtained by sediment traps and current meters, attached to moorings (April 2003-May 2004), and sediments samples analysed for biogeochemistry and grain size (May 2004). In November 2003, nematode SSs decreased with increasing depth (367.2 individuals and 7.31 ?g C per 10 cm2 at 388 m water depth to 7.7 individuals and 0.18 ?g C per 10 cm2 at 1677 m water depth), showing a significant negative relation (abundance: R2 = 0.620, p = 0.020; biomass: R2 = 0.512, p = 0.046). This was not the case in May 2004 (283.5 individuals and 3.53 ?g C per 10 cm2 at 388 m water depth to 490.8 individuals and 4.93 ?g C per 10 cm2 at 1677 m water depth; abundance: R2 = 0.003, p = 0.902; biomass: R2 = 0.052, p = 0.587), suggesting a temporal effect that overrides the traditional decrease of SSs with increasing water depth. Both water depth and sampling time played a significant role in explaining nematode SSs, but with differences between stations. No overall differences were observed between canyon and open slope stations. Nematode standing stock (SS) patterns can be explained by taking into account the interplay of phytodetrital input and disturbance events, with station differences such as topography playing an important role. Individual nematode size decreased from November 2003 to May 2004 and was explained by a food-induced genera shift and/or a food-induced transition from a ‘latent’ to a ‘reproductive’ nematode community. Our results suggest that size patterns in nematode communities are not solely governed by trophic conditions over longer periods of time in relatively food-rich environments such as canyons. We hypothesize that food pulses in a dynamic and topographical heterogeneous environment such as canyons regulate nematode size distributions, rather than long-term food availability. Feeding type distributions in the Blanes Canyon did not clearly resemble those from other canyon systems, apart from the spring assemblage at one station in the head of the canyon.

Ingels, Jeroen; Vanreusel, Ann; Romano, Chiara; Coenjaerts, Johan; Mar Flexas, M.; Zúñiga, Diana; Martin, Daniel

2013-11-01

269

Odor Concentration Invariance by Chemical Ratio Coding  

PubMed Central

Many animal species rely on chemical signals to extract ecologically important information from the environment. Yet in natural conditions chemical signals will frequently undergo concentration changes that produce differences in both level and pattern of activation of olfactory receptor neurons. Thus, a central problem in olfactory processing is how the system is able to recognize the same stimulus across different concentrations. To signal species identity for mate recognition, some insects use the ratio of two components in a binary chemical mixture to produce a code that is invariant to dilution. Here, using psychophysical methods, we show that rats also classify binary odor mixtures according to the molar ratios of their components, spontaneously generalizing over at least a tenfold concentration range. These results indicate that extracting chemical ratio information is not restricted to pheromone signaling and suggest a general solution for concentration-invariant odor recognition by the mammalian olfactory system. PMID:18958244

Uchida, Naoshige; Mainen, Zachary F.

2007-01-01

270

Meteorological Effects on Air/Fuel Ratio  

E-print Network

in humidity directly affect the volume percentage of oxygen. Since most ratio systems are unaware of changes in oxygen content of the air, the preset excess air rate will vary. This paper quantifies these variations and the method of calculation for any...

Ferri, J. L.

1984-01-01

271

Effects of Al2O3 and CaO/SiO2 Ratio on Phase Equilbria in the ZnO-"FeO"-Al2O3-CaO-SiO2 System in Equilibrium with Metallic Iron  

NASA Astrophysics Data System (ADS)

The phase equilibria and liquidus temperatures in the ZnO-"FeO"-Al2O3-CaO-SiO2 system in equilibrium with metallic iron have been determined experimentally in the temperature range 1383 K to 1573 K (1150 °C to 1300 °C). The experimental conditions were selected to characterize lead blast furnace and imperial smelting furnace slags. The results are presented in a form of pseudoternary sections ZnO-"FeO"-(Al2O3 + CaO + SiO2) with fixed CaO/SiO2 and (CaO + SiO2)/Al2O3 ratios. It was found that wustite and spinel are the major primary phases in the composition range investigated. Effects of Al2O3 concentration as well as the CaO/SiO2 ratio on the primary phase field, the liquidus temperature, and the partitioning of ZnO between liquid and solid phases have been discussed for zinc-containing slags.

Zhao, Baojun; Hayes, Peter C.; Jak, Evgueni

2011-02-01

272

Follistatin-like Protein 1 and the Ferritin/Erythrocyte Sedimentation Rate Ratio Are Potential Biomarkers for Dysregulated Gene Expression and Macrophage Activation Syndrome in Systemic Juvenile Idiopathic Arthritis  

PubMed Central

Objective Follistatin-like protein 1 (FSTL-1) is a secreted glycoprotein overexpressed in certain inflammatory diseases. Our objective was to correlate FSTL-1 levels with gene expression, known biomarkers, and measures of disease activity in systemic juvenile idiopathic arthritis (sJIA), including macrophage activation syndrome (MAS). Methods FSTL-1 serum levels were measured by ELISA in 28 patients with sJIA, including 7 patients who developed MAS, and 30 healthy controls. Levels were correlated with erythrocyte sedimentation rate (ESR), ferritin, and soluble interleukin-2 receptor-? (sIL-2R?). Gene expression based on FSTL-1 levels was analyzed in peripheral blood mononuclear cells (PBMC). Results Serum levels of FSTL-1 were elevated at time of presentation of sJIA (mean 200.7 ng/ml) and decreased to normal (mean 133.7 ng/ml) over 24 months (p < 0.01). FSTL-1 levels were markedly elevated during acute MAS (mean 279.8 ng/ml) and decreased to normal following treatment (p < 0.001). FSTL-1 levels correlated with serum markers of inflammation, including sIL-2R? and ferritin. Ferritin/ESR ratio was superior to ferritin, sIL-2R?, and FSTL-1 in discriminating MAS from new-onset sJIA. PBMC from patients with FSTL-1 levels > 200 ng/ml showed altered expression of genes related to innate immunity, erythropoiesis, and natural killer cell dysfunction. Two patients with the highest FSTL-1 levels at disease onset (> 300 ng/ml) ultimately developed MAS. Conclusion Elevated pretreatment serum FSTL-1 levels in sJIA are associated with dysregulated gene expression suggestive of occult MAS, and may have utility in predicting progression to overt MAS. Ferritin/ESR ratio may be superior to ferritin alone in discriminating overt MAS from new-onset sJIA. (First Release May 15 2013; J Rheumatol 2013;40:1191–9; doi:10.3899/jrheum.121131) PMID:23678162

Gorelik, Mark; Fall, Ndate; Altaye, Mekibib; Barnes, Michael G.; Thompson, Susan D.; Grom, Alexei A.; Hirsch, Raphael

2013-01-01

273

Point Estimation: Odds Ratios, Hazard Ratios, Risk Differences, Precision  

NSDL National Science Digital Library

This site provides a PowerPoint presentation, created by Dr. Elizabeth Garrett-Mayer of Johns Hopkins University, of a lesson and examples of point estimation, odds ratios, hazard ratios, risk differences and precision. The presentations is quite thorough. The author attempts to define, provide examples of, and then show the application of almost every concept. The presentation follows a easily followed and logical order. Mathematical formulas are intertwined within the slides. If further research is necessary, the author has provided a list of references and cites them during the presentation.

Garrett-Mayer, Elizabeth

2009-02-11

274

The initial mass ratio of solar type contact binaries  

NASA Astrophysics Data System (ADS)

The initial mass ratio distribution function, which gives the normalized number of binary objects formed at a given mass ratio, is computed for solar-type contact binaries (W UMa stars). The initial function is derived from the present mass ratio distribution function by integrating backwards in time based on a mass ratio evolution function describing the variation of the mass ratio with time since the coming into contact of the components, which is determined by the rate of angular momentum loss which is in turn determined by the total mass and mass ratio of the system. All contact binaries produced are found to exhibit initial mass ratios greater than 0.8, indicating that the components had nearly equal masses. Implications of the results for RS CVn stars are noted.

van t Veer, F.

1981-05-01

275

Discovering Phi: The Golden Ratio  

NSDL National Science Digital Library

Students discover the mathematical constant phi, the golden ratio, through hands-on activities. They measure dimensions of "natural objects"—a star, a nautilus shell and human hand bones—and calculate ratios of the measured values, which are close to phi. Then students learn a basic definition of a mathematical sequence, specifically the Fibonacci sequence. By taking ratios of successive terms of the sequence, they find numbers close to phi. They solve a squares puzzle that creates an approximate Fibonacci spiral. Finally, the instructor demonstrates the rule of the Fibonacci sequence via a LEGO® MINDSTORMS® NXT robot equipped with a pen. The robot (already created as part of the companion activity, The Fibonacci Sequence & Robots) draws a Fibonacci spiral that is similar to the nautilus shape.

AMPS GK-12 Program,

276

Thin solar concentrator with high concentration ratio  

NASA Astrophysics Data System (ADS)

Solar concentrators are often used in conjunction with III-V multi-junction solar cells for cost reduction and efficiency improvement purposes. High flux concentration ratio, high optical efficiency and high manufacture tolerance are the key features required for a successful solar concentrator design. This paper describes a novel solar concentrator that combines the concepts, and thus the advantages, of both the refractive type ad reflective type. The proposed concentrator design adopts the Etendue-cascading concept that allows the light beams from all the concentric annular entrance pupils to be collected and transferred to the solar cell with minimal loss. This concept enables the system to perform near its Etendue-Limit and have a high concentration ratio simultaneously. Thereby reducing the costs of solar cells and therefor achieves a better the per watts cost. The concentrator demonstrated has a thing aspect ratio of 0.19 with a zero back focal distance. The numerical aperture at the solar cell immersed inside the dielectric concentrator is as high as 1.33 achieving a unprecedented high optical concentration ratio design.

Lin, Jhe-Syuan; Liang, Chao-Wen

2013-09-01

277

Measurement of tau branching ratios  

Microsoft Academic Search

We have measured the branching ratios for several tau decay modes. We use e+e--->tau+tau- events accumulated with the TPC\\/Two-Gamma facility at the SLAC e+e- storage ring PEP. The data correspond to an integrated luminosity of 77 pb-1 at a center-of-mass energy of 29 GeV. The one- and three-charged-particle inclusive branching ratios of the tau decay are measured to be B1=(84.7+\\/-1.0)%

H. Aihara; M. Alston-Garnjost; R. E. Avery; J. A. Bakken; A. Barbaro-Galtieri; A. R. Barker; A. V. Barnes; B. A. Barnett; D. A. Bauer; H.-U. Bengtsson; D. L. Bintinger; G. J. Bobbink; T. S. Bolognese; A. D. Bross; C. D. Buchanan; A. Buijs; D. O. Caldwell; C.-Y. Chien; A. R. Clark; G. D. Cowan; D. A. Crane; O. I. Dahl; K. A. Derby; J. J. Eastman; T. K. Edberg; P. H. Eberhard; A. M. Eisner; R. Enomoto; F. C. Erné; T. Fujii; J. W. Gary; W. Gorn; J. M. Hauptman; W. Hofmann; J. E. Huth; J. Hylen; T. Kamae; H. S. Kaye; K. H. Kees; R. W. Kenney; L. T. Kerth; Winston Ko; R. I. Koda; R. R. Kofler; K. K. Kwong; R. L. Lander; W. G. Langeveld; J. G. Layter; F. L. Linde; C. S. Lindsey; S. C. Loken; A. Lu; X.-Q. Lu; G. R. Lynch; L. Madansky; R. J. Madaras; K. Maeshima; B. D. Magnuson; J. N. Marx; G. E. Masek; L. G. Mathis; J. A. Matthews; S. J. Maxfield; S. O. Melnikoff; E. S. Miller; W. Moses; R. R. McNeil; P. Nemethy; D. R. Nygren; P. J. Oddone; H. P. Paar; D. A. Park; S. K. Park; D. E. Pellett; A. Pevsner; M. Pripstein; M. T. Ronan; R. R. Ross; F. R. Rouse; K. A. Schwitkis; J. C. Sens; G. Shapiro; M. D. Shapiro; B. C. Shen; W. E. Slater; J. R. Smith; J. S. Steinman; M. L. Stevenson; D. H. Stork; M. G. Strauss; M. K. Sullivan; T. Takahashi; J. R. Thompson; N. Toge; S. Toutounchi; R. van Tyen; B. van Uitert; G. J. Vandalen; R. F. van Daalen Wetters; W. Vernon; W. Wagner; E. M. Wang; Y. X. Wang; M. R. Wayne; W. A. Wenzel; J. T. White; M. C. Williams; Z. R. Wolf; H. Yamamoto; S. J. Yellin; C. Zeitlin; W.-M. Zhang

1987-01-01

278

Surface to Volume Ratio Activity  

NSDL National Science Digital Library

By the National Nanotechnology Infrastructure Network, this two-part laboratory activity was designed to complement any chemistry unit on catalysts to "help students understand how nanoparticles may be more effective catalysts by investigating how the surface area-to-volume ratio of a substance is affected as its shape changes." On this site, educators can find both the teacher and student instructions for preparing and presenting the laboratory with objectives, time periods, materials, procedures, example answers, and much more. It is a ready-to-use lesson to help students understand catalysts and surface to volume ratio at molecular and atomic levels.

279

Energy Balance Bowen Ratio Station (EBBR) Handbook  

SciTech Connect

The energy balance Bowen ratio (EBBR) system produces 30-minute estimates of the vertical fluxes of sensible and latent heat at the local surface. Flux estimates are calculated from observations of net radiation, soil surface heat flux, and the vertical gradients of temperature and relative humidity (RH). Meteorological data collected by the EBBR are used to calculate bulk aerodynamic fluxes, which are used in the Bulk Aerodynamic Technique (BA) EBBR value-added product (VAP) to replace sunrise and sunset spikes in the flux data. A unique aspect of the system is the automatic exchange mechanism (AEM), which helps to reduce errors from instrument offset drift.

Cook, DR

2011-02-23

280

Diffuse-direct ultraviolet ratios with a compact double monochromator  

NASA Technical Reports Server (NTRS)

An improved system has been implemented for measuring the ratio of the diffuse skylight to the direct sunlight in the biologically active region of the UV near the atmospheric limit. It combines a double monochromator employing holographic gratings for reduction of stray light with a cooled photomultiplier tube to provide a greatly improved SNR below 300 nm. Data may be obtained in either a scan mode or a narrowband photometry mode; in the latter mode accurate ratios have been obtained near 290 nm. Representative data are discussed along with a theoretical model of the ratio. The system is compact enough for use in a mobile monitoring system.

Garrison, L. M.; Murray, L. E.; Doda, D. D.; Green, A. E. S.

1978-01-01

281

A Ratio Explanation for Evolution.  

ERIC Educational Resources Information Center

Describes hands-on physical anthropology activities for teaching students about evolution. Using evidence found in hominid skulls, students conduct investigations that involve calculating ratios. Eight full-page photographs of skulls from the program Stones and Bones are included. (PR)

Riss, Pam Helfers

1993-01-01

282

Empirical Likelihood Ratio Confidence Regions  

Microsoft Academic Search

An empirical likelihood ratio function is defined and used to obtain confidence regions for vector valued statistical functionals. The result is a nonparametric version of Wilks' theorem and a multivariate generalization of work by Owen. Cornish-Fisher expansions show that the empirical likelihood intervals for a one dimensional mean are less adversely affected by skewness than are those based on Student's

Art Owen

1990-01-01

283

Envera Variable Compression Ratio Engine  

Microsoft Academic Search

Aggressive engine downsizing, variable compression ratio and use of the Atkinson cycle are being combined to improve fuel economy by up to 40 percent relative to port fuel injected gasoline engines, while maintaining full engine power. Approach Engine downsizing is viewed by US and foreign automobile manufacturers as one of the best options for improving fuel economy. While this strategy

Charles Mendler

2011-01-01

284

Optimal gear ratios of drives  

Microsoft Academic Search

One of the most complex problems in the design of practically any mechanism or machine is to select the gear ratio of an electric drive, on the basis of scientific, engineering, and economic principles. There is an extensive literature on this subject, dating mainly to the period from the 1940s to the 1960s. In current economic conditions, however, this problem

B. N. Polyakov

2007-01-01

285

Effects of spatial and temporal variability on simulated transpiration ratios  

Microsoft Academic Search

Sustainability studies are increasingly needed to determine management systems that protect the environment and maintain production potentials. Whether these analyses are performed by field experiments or by computer modelling, defining the appropriate spatial and temporal scales is essential. For three management types within one soil series in The Netherlands, the land quality indicator “transpiration ratio”, Eratio (ratio between actual and

P. Droogers

1997-01-01

286

Light scattering: landau-placzek ratio and total intensity  

Microsoft Academic Search

The total light scattering intensity and the Landau-Placzek ratio are calculated, via thermodynamic arguments, from a model system representative of a single component relaxing fluid or a reactive binary mixture. Comparison is made with both previous thermodynamic calculations of the Landau-Placzek ratio and the results obtained from integration of the intensity distribution. In addition, the fluctuations of the dielectric constant

Michael Weinberg

1974-01-01

287

Thread motion ratio used to monitor sewing machines  

Microsoft Academic Search

A prototype system for detecting sewing defects through analysis of thread motion has been developed. A piezo-electric transducer provides information on the time of motion of the top thread in a lockstitch sewing process. The ratio of this time of motion to the total single sewing cycle time is a measure termed the thread motion ratio. This measure offers consistency

J. Lewis Dorrity; L. Howard Olson

1996-01-01

288

Focal ratio degradation in lightly fused hexabundles  

NASA Astrophysics Data System (ADS)

We are now moving into an era where multi-object wide-field surveys, which traditionally use single fibres to observe many targets simultaneously, can exploit compact integral field units (IFUs) in place of single fibres. Current multi-object integral field instruments such as Sydney-AAO Multi-object Integral field spectrograph have driven the development of new imaging fibre bundles (hexabundles) for multi-object spectrographs. We have characterized the performance of hexabundles with different cladding thicknesses and compared them to that of the same type of bare fibre, across the range of fill fractions and input f-ratios likely in an IFU instrument. Hexabundles with 7-cores and 61-cores were tested for focal ratio degradation (FRD), throughput and cross-talk when fed with inputs from F/3.4 to >F/8. The five 7-core bundles have cladding thickness ranging from 1 to 8 ?m, and the 61-core bundles have 5 ?m cladding. As expected, the FRD improves as the input focal ratio decreases. We find that the FRD and throughput of the cores in the hexabundles match the performance of single fibres of the same material at low input f-ratios. The performance results presented can be used to set a limit on the f-ratio of a system based on the maximum loss allowable for a planned instrument. Our results confirm that hexabundles are a successful alternative for fibre imaging devices for multi-object spectroscopy on wide-field telescopes and have prompted further development of hexabundle designs with hexagonal packing and square cores.

Bryant, J. J.; Bland-Hawthorn, J.; Fogarty, L. M. R.; Lawrence, J. S.; Croom, S. M.

2014-02-01

289

In-line process control for laser welding of titanium by high dynamic range ratio pyrometry and plasma spectroscopy  

NASA Astrophysics Data System (ADS)

The production of complex titanium components for various industries using laser welding processes has received growing attention in recent years. It is important to know whether the result of the cohesive joint meets the quality requirements of standardization and ultimately the customer requirements. Erroneous weld seams can have fatal consequences especially in the field of car manufacturing and medicine technology. To meet these requirements, a real-time process control system has been developed which determines the welding quality through a locally resolved temperature profile. By analyzing the resulting weld plasma received data is used to verify the stability of the laser welding process. The determination of the temperature profile is done by the detection of the emitted electromagnetic radiation from the material in a range of 500 nm to 1100 nm. As detectors, special high dynamic range CMOS cameras are used. As the emissivity of titanium depends on the wavelength, the surface and the angle of radiation, measuring the temperature is a problem. To solve these a special pyrometer setting with two cameras is used. That enables the compensation of these effects by calculating the difference between the respective pixels on simultaneously recorded images. Two spectral regions with the same emissivity are detected. Therefore the degree of emission and surface effects are compensated and canceled out of the calculation. Using the spatially resolved temperature distribution the weld geometry can be determined and the laser process can be controlled. The active readjustment of parameters such as laser power, feed rate and inert gas injection increases the quality of the welding process and decreases the number of defective goods.

Lempe, B.; Taudt, C.; Baselt, T.; Rudek, F.; Maschke, R.; Basan, F.; Hartmann, P.

2014-02-01

290

The basic reproductive ratio of life  

PubMed Central

Template-directed polymerization of nucleotides is believed to be a pathway for the replication of genetic material in the earliest cells. We assume that activated monomers are produced by prebiotic chemistry. These monomers can undergo spontaneous polymerization, a system that we call “prelife.” Adding template-directed polymerization changes the equilibrium structure of prelife if the rate constants meet certain criteria. In particular, if the basic reproductive ratio of sequences of a certain length exceeds one, then those sequences can attain high abundance. Furthermore, if many sequences replicate, then the longest sequences can reach high abundance even if the basic reproductive ratios of all sequences are less than one. We call this phenomenon “subcritical life.” Subcritical life suggests that sequences long enough to be ribozymes can become abundant even if replication is relatively inefficient. Our work on the evolution of replication has interesting parallels to infection dynamics. Life (replication) can be seen as an infection of prelife. PMID:20034501

Manapat, Michael L.; Chen, Irene A.; Nowak, Martin A.

2010-01-01

291

Prevalence odds ratio or prevalence ratio in the analysis of cross sectional data: what is to be done?  

Microsoft Academic Search

OBJECTIVES: To review the appropriateness of the prevalence odds ratio (POR) and the prevalence ratio (PR) as effect measures in the analysis of cross sectional data and to evaluate different models for the multivariate estimation of the PR. METHODS: A system of linear differential equations corresponding to a dynamic model of a cohort with a chronic disease was developed. At

M. L. Thompson; J. E. Myers; D. Kriebel

1998-01-01

292

Blowing Ratio Effects on Film Cooling Effectiveness  

E-print Network

coolant tends to attach closer to the blade surface compared to the light density ratio coolant at the same blowing ratio. 10 Sinha et al. [18] studied similarly on various density ratio coolants under different blowing ratio. For a constant density ratio...

Liu, Kuo-Chun

2010-01-14

293

Optomechanical Raman-Ratio Thermometry  

E-print Network

The temperature dependence of the asymmetry between Stokes and anti-Stokes Raman scattering can be exploited for self-calibrating, optically-based thermometry. In the context of cavity optomechanics, we observe the cavity-enhanced scattering of light interacting with the standing-wave drumhead modes of a silicon nitride membrane mechanical resonator. The ratio of the amplitude of Stokes to anti-Stokes scattered light is used to measure temperatures of optically-cooled mechanical modes down to the level of a few vibrational quanta. We demonstrate that the Raman-ratio technique is able to measure the physical temperature of our device over a range extending from cryogenic temperatures to within an order of magnitude of room temperature.

T. P. Purdy; P. -L. Yu; N. S. Kampel; R. W. Peterson; K. Cicak; R. W. Simmonds; C. A. Regal

2014-06-27

294

GUT Scale Fermion Mass Ratios  

NASA Astrophysics Data System (ADS)

We present a series of recent works related to group theoretical factors from GUT symmetry breaking which lead to predictions for the ratios of quark and lepton Yukawa couplings at the unification scale. New predictions for the GUT scale ratios y?/ys, y?/yb and yt/yb in particular are shown and compared to experimental data. For this comparison it is important to include possibly large supersymmetric threshold corrections. Due to this reason the structure of the fermion masses at the GUT scale depends on TeV scale physics and makes GUT scale physics testable at the LHC. We also discuss how this new predictions might lead to predictions for mixing angles by discussing the example of the recently measured last missing leptonic mixing angle ?13 making this new class of GUT models also testable in neutrino experiments.

Spinrath, Martin

2014-10-01

295

Models of Ratio Schedule Performance  

PubMed Central

Predictions of P. R. Killeen's (1994) mathematical principles of reinforcement were tested for responding on ratio reinforcement schedules. The type of response key, the number of sessions per condition, and first vs. second half of a session had negligible effects on responding. Longer reinforcer durations and larger grain types engeridered more responding, affecting primarily the parameter a (specific activation). Key pecking was faster than treadle pressing, affecting primarily the parameter ? (response time). Longer intertrial intervals led to higher overall response rates and shorter postreinforcement pauses and higher running rates, and ruled out some competing explanations. The treadle data required a distinction between the energetic requirements and rate-limiting properties of extended responses. The theory was extended to predict pause durations and run rates on ratio schedules. PMID:9206029

Bizo, Lewis A.; Killeen, Peter R.

2008-01-01

296

Raindrop shape limitations on clutter cancellation ratio using circular polarization  

NASA Astrophysics Data System (ADS)

Cancellation ratio limitations from raindrop properties in a perfectly circularly polarized radar system were found using a new raindrop size distribution which has an improved fit to the existing empirical data. Winds and multiple reflections between raindrops were not considered.

Lind, G.; Sekine, M.

1983-07-01

297

Rational Industrial Water Reuse Ratios  

NASA Astrophysics Data System (ADS)

This work begins by defining rational water use, and then discusses important factors that most strongly influence it. A general model is then developed to enable factories to quantify the ratio of rational industrial water reuse based on the least cost method. The model is established to minimize the cost of water with reference to gross water use and three subsystems - the intake, reuse, and discharge of industrial water. Discharge cost is determined using data from a 1997 survey of 38 factories, and reuse costs are ranked and expressed by a step function. The model is verified using data from a typical semiconductor factory in northern Taiwan's Hsinchu Science Based Industrial Park, whose effective rational water reuse ratio is about 38 percent. A sensitivity analysis shows that improving water reuse technology is the most important factor in determining the rational water reuse ratio, and the price of water is the second most important. When water costs over NT30 (New Taiwan Dollar, US1 = NT$34) per cubic meter, increasing reuse becomes significant. The model provides a step towards the scientific management of industrial water.

Liaw, Chao-Hsien; Chen, Liang-Ching

2004-08-01

298

Envera Variable Compression Ratio Engine  

SciTech Connect

Aggressive engine downsizing, variable compression ratio and use of the Atkinson cycle are being combined to improve fuel economy by up to 40 percent relative to port fuel injected gasoline engines, while maintaining full engine power. Approach Engine downsizing is viewed by US and foreign automobile manufacturers as one of the best options for improving fuel economy. While this strategy has already demonstrated a degree of success, downsizing and fuel economy gains are currently limited. With new variable compression ratio technology however, the degree of engine downsizing and fuel economy improvement can be greatly increased. A small variable compression ratio (VCR) engine has the potential to return significantly higher vehicle fuel economy while also providing high power. Affordability and potential for near term commercialization are key attributes of the Envera VCR engine. VCR Technology To meet torque and power requirements, a smaller engine needs to do more work per stroke. This is typically accomplished by boosting the incoming charge with either a turbo or supercharger so that more energy is present in the cylinder per stroke to do the work. With current production engines the degree of engine boosting (which correlates to downsizing) is limited by detonation (combustion knock) at high boost levels. Additionally, the turbo or supercharger needs to be responsive and efficient while providing the needed boost. VCR technology eliminates the limitation of engine knock at high load levels by reducing compression ratio to {approx}9:1 (or whatever level is appropriate) when high boost pressures are needed. By reducing the compression ratio during high load demand periods there is increased volume in the cylinder at top dead center (TDC) which allows more charge (or energy) to be present in the cylinder without increasing the peak pressure. Cylinder pressure is thus kept below the level at which the engine would begin to knock. When loads on the engine are low the compression ratio can be raised (to as much as 18:1) providing high engine efficiency. It is important to recognize that for a well designed VCR engine cylinder pressure does not need to be higher than found in current production turbocharged engines. As such, there is no need for a stronger crankcase, bearings and other load bearing parts within the VCR engine. The Envera VCR mechanism uses an eccentric carrier approach to adjust engine compression ratio. The crankshaft main bearings are mounted in this eccentric carrier or 'crankshaft cradle' and pivoting the eccentric carrier 30 degrees adjusts compression ratio from 9:1 to 18:1. The eccentric carrier is made up of a casting that provides rigid support for the main bearings, and removable upper bearing caps. Oil feed to the main bearings transits through the bearing cap fastener sockets. The eccentric carrier design was chosen for its low cost and rigid support of the main bearings. A control shaft and connecting links are used to pivot the eccentric carrier. The control shaft mechanism features compression ratio lock-up at minimum and maximum compression ratio settings. The control shaft method of pivoting the eccentric carrier was selected due to its lock-up capability. The control shaft can be rotated by a hydraulic actuator or an electric motor. The engine shown in Figures 3 and 4 has a hydraulic actuator that was developed under the current program. In-line 4-cylinder engines are significantly less expensive than V engines because an entire cylinder head can be eliminated. The cost savings from eliminating cylinders and an entire cylinder head will notably offset the added cost of the VCR and supercharging. Replacing V6 and V8 engines with in-line VCR 4-cylinder engines will provide high fuel economy at low cost. Numerous enabling technologies exist which have the potential to increase engine efficiency. The greatest efficiency gains are realized when the right combination of advanced and new technologies are packaged together to provide the greatest gains at the least cost. Aggressive engine downsiz

Charles Mendler

2011-03-15

299

Adaptive focusing - The likelihood ratio  

NASA Astrophysics Data System (ADS)

The problem of detecting a certain non-Gaussian random acoustic signal field in a spatially white Gaussian noise field is solved within the formalism of classical detection theory. Two solutions of the problem are compared: the maximum-likelihood or adaptive-focusing receiver and the Neyman-Pearson or adaptive focusing optimal (AFO) receiver. Based on two criteria for comparison, it is found that the two receivers differ only slightly in performance, with the AFO, of course, being the better. One of the criteria is based on the signal deflection ratio, and the other is the receiver operating characteristic curve. The comparisons are done for a Monte Carlo simulation.

Labianca, F. M.; Lloyd, S. P.

1981-08-01

300

High-aspect-ratio wings  

NASA Technical Reports Server (NTRS)

High-aspect-ratio aircraft include most transport aircraft such as commercial and military transports, business aircraft, and cargo aircraft. Generally, these types of aircraft are designed to cruise over a narrow range of lift coefficients and Mach numbers in the performance of their mission. Emphasis is therefore placed on the cruise performance of transport aircraft and every effort is made to obtain accurate wind-tunnel data to use as a basis for prediction of full-scale cruise performance. However, off-cruise performance is also important and methods were developed for extrapolating wind-tunnel data on buffet and flutter at transonic speed. Transport-type aircraft were tested extensively in various wind tunnels around the world and many different test techniques were developed to simulate higher Reynolds numbers. Methods developed for one tunnel may not be applicable to another tunnel because of differences in size, Reynolds number capability, running time, and test objectives. Many of the methods of boundary-layer control developed in two-dimensional airfoil testing can be applied in tests of transport configurations, but sometimes the three-dimensional flow fields that develop on tranpsort aircraft can make application of the two-dimensional methods difficult or impossible. The discussion is intended to be a representative, but not exhaustive, survey of the various methods of high Reynolds number simulation in the testing of high-aspect-ratio aircraft.

Peterson, John B., Jr.

1988-01-01

301

The C-12/C-13 Ratio as a Chemistry Indicator  

NASA Technical Reports Server (NTRS)

Isotopic ratios of elements are considered powerful tools, e.g. in tracing the origin of solar system body materials, or the degree of nucleosynthesis processing throughout the Galaxy. In interstellar molecules, some isotopic ratios like H/D and C-12/C-13 can also be used as indicators of their chemical origin. Isotope fractionation in gas-phase chemical reactions and gas-dust interaction makes observations of the ratio between C-12 and C-13 isotopologues suitable to distinguish between different formation scenarios. We will present observations of the C-12/C-13 ratio in methanol and formaldehyde towards a sample of embedded, massive young stellar objects. In relation to this we also present results from theoretical modeling showing the usefulness of the C-12/C-13 ratio as a chemistry indicator.

Wirstroem, Eva; Geppert, Wolf; Persson, Carina; Charnley, Steven

2011-01-01

302

Effect of fuel-air-ratio nonuniformity on emissions of nitrogen oxides  

NASA Technical Reports Server (NTRS)

The inlet fuel-air ratio nonuniformity is studied to deterine how nitrogen oxide (NOx) emissions are affected. An increase in NOx emissions with increased fuel-air ratio nonuniformity for average equivalence ratios less than 0.7 and a decrease in NOx emissions for average equivalence ratios near stoichiometric is predicted. The degree of uniformityy of fuel-air ratio profiles that is necessary to achieve NOx emissions goals for actual engines that use lean, premixed, prevaporized combustion systems is determined.

Lyons, V. J.

1981-01-01

303

Noise of Embedded High Aspect Ratio Nozzles  

NASA Technical Reports Server (NTRS)

A family of high aspect ratio nozzles were designed to provide a parametric database of canonical embedded propulsion concepts. Nozzle throat geometries with aspect ratios of 2:1, 4:1, and 8:1 were chosen, all with convergent nozzle areas. The transition from the typical round duct to the rectangular nozzle was designed very carefully to produce a flow at the nozzle exit that was uniform and free from swirl. Once the basic rectangular nozzles were designed, external features common to embedded propulsion systems were added: extended lower lip (a.k.a. bevel, aft deck), differing sidewalls, and chevrons. For the latter detailed Reynolds-averaged Navier-Stokes (RANS) computational fluid dynamics (CFD) simulations were made to predict the thrust performance and to optimize parameters such as bevel length, and chevron penetration and azimuthal curvature. Seventeen of these nozzles were fabricated at a scale providing a 2.13 inch diameter equivalent area throat." ! The seventeen nozzles were tested for far-field noise and a few data were presented here on the effect of aspect ratio, bevel length, and chevron count and penetration. The sound field of the 2:1 aspect ratio rectangular jet was very nearly axisymmetric, but the 4:1 and 8:1 were not, the noise on their minor axes being louder than the major axes. Adding bevel length increased the noise of these nozzles, especially on their minor axes, both toward the long and short sides of the beveled nozzle. Chevrons were only added to the 2:1 rectangular jet. Adding 4 chevrons per wide side produced some decrease at aft angles, but increased the high frequency noise at right angles to the jet flow. This trend increased with increasing chevron penetration. Doubling the number of chevrons while maintaining their penetration decreased these effects. Empirical models of the parametric effect of these nozzles were constructed and quantify the trends stated above." Because it is the objective of the Supersonics Project that future design work be done more by physics-based computations and less by experiments, several codes under development were evaluated against these test cases. Preliminary results show that the RANS-based code JeNo predicts the spectral directivity of the low aspect ratio jets well, but has no capability to predict the non-axisymmetry. An effort to address this limitations, used in the RANS-based code of Leib and Goldstein, overpredicted the impact of aspect ratio. The broadband shock noise code RISN, also limited to axisymmetric assumptions, did a good job of predicting the spectral directivity of underexpanded 2:1 cold jet case but was not as successful on high aspect ratio jets, particularly when they are hot. All results are preliminary because the underlying CFD has not been validated yet. An effort using a Large Eddy Simulation code by Stanford University predicted noise that agreed with experiments to within a few dB.

Bridges, James E.

2011-01-01

304

A theoretically based determination of bowen-ratio fetch requirements  

USGS Publications Warehouse

Determination of fetch requirements for accurate Bowen-ratio measurements of latent- and sensible-heat fluxes is more involved than for eddy-correlation measurements because Bowen-ratio sensors are located at two heights, rather than just one. A simple solution to the diffusion equation is used to derive an expression for Bowen-ratio fetch requirements, downwind of a step change in surface fluxes. These requirements are then compared to eddy-correlation fetch requirements based on the same diffusion equation solution. When the eddy-correlation and upper Bowen-ratio sensor heights are equal, and the available energy upwind and downwind of the step change is constant, the Bowen-ratio method requires less fetch than does eddy correlation. Differences in fetch requirements between the two methods are greatest over relatively smooth surfaces. Bowen-ratio fetch can be reduced significantly by lowering the lower sensor, as well as the upper sensor. The Bowen-ratio fetch model was tested using data from a field experiment where multiple Bowen-ratio systems were deployed simultaneously at various fetches and heights above a field of bermudagrass. Initial comparisons were poor, but improved greatly when the model was modified (and operated numerically) to account for the large roughness of the upwind cotton field.

Stannard, D.I.

1997-01-01

305

Measuring Method of Oil Circulation Ratio Using Light Absorption  

NASA Astrophysics Data System (ADS)

A new measuring method of the oil circulation ratio in the liquid line of refrigeration systems was invented by using the property of oil absorbing light. The absorption and reference wavelengths were determined in consideration of the asorption spectra of liquid refrigerant and lubricating oil. Next, the oil circulation ratio and transmittance ratio were investigated on the effect of solution temperature in the cases of CFC-12 and HFC-134a and then were confirmed on the influence of soiled-oil and moisture. This method is accurate and available to nonlight-absorbing CFC-12 and light-absorbing HFC134a, which requires temperature correction.

Suzuki, Shinichi; Fujisawa, Yoshihiro; Nakazawa, Sotaro; Matsuoka, Manabu

306

Temperature Calibration for Optical Pyrometry in Containerless Systems Using Differential Scanning Calorimetry: Application to (-50)  

NASA Astrophysics Data System (ADS)

Accurate and precise measurements of the temperature are important for controlling conditions in any experimental design. In containerless processing, such as in electrostatic levitation and electromagnetic levitation, the temperature is typically measured using optical pyrometers. These are generally calibrated to the sample of interest by measuring the temperatures of phase transitions. The presence of multiple heat signatures, differences in emissivity for different phases, and inconsistencies in published phase diagrams can make this difficult. In this manuscript, a method for using differential scanning calorimetry measurements for calibration is outlined and applied to four Cu-Zr alloys from the eutectic to the line compound. This technique is particularly valuable for systems in which accurate phase diagram information is unavailable or inaccurate.

Bendert, J. C.; Pueblo, C. E.; Veligati, S.; Mauro, N. A.; Kelton, K. F.

2014-10-01

307

Double Stage Heat Transformer Controlled by Flow Ratio  

Microsoft Academic Search

this paper shows the values of Flow ratio (FR) for control of an absorption double stage heat transformer. The main parameters for the heat pump system are defined as COP, FR and GTL. The control of the entire system is based in a new definition of FR. The heat balance of the Double Stage Heat Transformer (DSHT) is used for

S. Silva-Sotelo; R. J. Romero Domínguez; A. Rodríguez--Martínez

2009-01-01

308

A method to deconvolve mass ratio distribution of binary stars  

NASA Astrophysics Data System (ADS)

Aims: It is important to know the binary mass-ratio distribution to better understand the evolution of stars in binary systems and to constrain their formation. However, in most cases, that is, for single-lined spectroscopic binaries, the mass ratio cannot be measured directly, but can only be derived as the convolution of a function that depends on the mass ratio and on the unknown inclination angle of the orbit on the plane of the sky. Methods: We extend our previous method for deconvolving this inverse problem by obtaining the cumulative distribution function (CDF) for the mass-ratio distribution as an integral. Results: After a suitable transformation of variables, this problem becomes the same as the problem of rotational velocities vsini, allowing a close analytic formulation for the CDF. We here apply our method to two real datasets: a sample of Am star binary systems, and a sample of massive spectroscopic binaries in the Cyg OB2 association. Conclusions: We are able to reproduce previous results for the sample of Am stars. In addition, the mass-ratio distribution of massive stars shows an excess of systems with a low mass ratio, in contrast to what was claimed elsewhere. Our method proves to be very reliable and deconvolves the distribution from a sample in one single step.

Curé, Michel; Rial, Diego F.; Cassetti, Julia; Christen, Alejandra; Boffin, Henri M. J.

2015-01-01

309

Implications of Fast Reactor Transuranic Conversion Ratio  

SciTech Connect

Theoretically, the transuranic conversion ratio (CR), i.e. the transuranic production divided by transuranic destruction, in a fast reactor can range from near zero to about 1.9, which is the average neutron yield from Pu239 minus 1. In practice, the possible range will be somewhat less. We have studied the implications of transuranic conversion ratio of 0.0 to 1.7 using the fresh and discharge fuel compositions calculated elsewhere. The corresponding fissile breeding ratio ranges from 0.2 to 1.6. The cases below CR=1 (“burners”) do not have blankets; the cases above CR=1 (“breeders”) have breeding blankets. The burnup was allowed to float while holding the maximum fluence to the cladding constant. We graph the fuel burnup and composition change. As a function of transuranic conversion ratio, we calculate and graph the heat, gamma, and neutron emission of fresh fuel; whether the material is “attractive” for direct weapon use using published criteria; the uranium utilization and rate of consumption of natural uranium; and the long-term radiotoxicity after fuel discharge. For context, other cases and analyses are included, primarily once-through light water reactor (LWR) uranium oxide fuel at 51 MWth-day/kg-iHM burnup (UOX-51). For CR<1, the heat, gamma, and neutron emission increase as material is recycled. The uranium utilization is at or below 1%, just as it is in thermal reactors as both types of reactors require continuing fissile support. For CR>1, heat, gamma, and neutron emission decrease with recycling. The uranium utilization exceeds 1%, especially as all the transuranic elements are recycled. exceeds 1%, especially as all the transuranic elements are recycled. At the system equilibrium, heat and gamma vary by somewhat over an order of magnitude as a function of CR. Isotopes that dominate heat and gamma emission are scattered throughout the actinide chain, so the modest impact of CR is unsurprising. Neutron emitters are preferentially found among the higher actinides, so the neutron emission varies much stronger with CR, about three orders of magnitude.

Steven J. Piet; Edward A. Hoffman; Samuel E. Bays

2010-11-01

310

Temperature-controlled electrothermal atomization-atomic absorption spectrometry using a pyrometric feedback system in conjunction with a background monitoring device  

NASA Astrophysics Data System (ADS)

The construction of a temperature-controlled feedback system for electrothermal atomization-atomic absorption spectrometry (ETA-AAS) using an optical pyrometer applied to the atomization stage is described. The system was used in conjunction with a fast-response background monitoring device. The heating rate of the furnace amounted to 1400° s -1 with a reproducibility better than 1%. The precision of the temperature control at a steady state temperature of 2000°C was 0.1%. The analytical improvements offered by the present system have been demonstrated by the determination of cadmium and lead in blood and finally by the determination of lead in serum. Both the sensitivity and the precision of the method have been improved. The accuracy of the method was checked by determining the lead content for a number of scrum samples both by ETA-AAS and differential pulse anodic stripping voltametry (DPASV) and proved to be satisfactory.

Van Deijck, W.; Roelofsen, A. M.; Pieters, H. J.; Herber, R. F. M.

311

LEP/FEP Graduation Ratios.  

ERIC Educational Resources Information Center

A study examined the characteristics of 14 students entering the American school system as non-English-speaking adolescents, yet achieving the level of academic content learning and English language proficiency to earn a high school diploma. The subjects of the study were classified in grade 12 as speaking a language other than English at home and…

Olsen, Roger E.; McCall, Zaida

312

Gyromagnetic Ratios of Bound Particles  

Microsoft Academic Search

A new approach to calculation of the binding corrections to the magnetic moments of the constituents in a loosely bound system based, on the Bargmann–Michel–Telegdi equation, is suggested. Binding corrections are calculated in this framework, and the results confirm earlier calculations performed by other methods. Our method clearly demonstrates independence of the binding corrections on the magnitude of the spin

Michael I. Eides; Howard Grotch

1997-01-01

313

TRIGONOMETRY: COMPARING RATIO AND UNIT CIRCLE METHODS  

Microsoft Academic Search

Before the 1960s, introductory trigonometry was taught in Victorian schools using the ratio method, where trigonometric functions are defined as ratios of sides of right angled triangles. With the advent of \\

Margaret Kendal; Kaye Stacey

314

Variable mixture ratio performance through nitrogen augmentation  

NASA Technical Reports Server (NTRS)

High/variable mixture ratio O2/H2 candidate engine cycles are examined for earth-to-orbit vehicle application. Engine performance and power balance information are presented for the candidate cycles relative to chamber pressure, bulk density, and mixture ratio. Included in the cycle screening are concepts where a third fluid (liquid nitrogen) is used to achieve a variable mixture ratio over the trajectory from liftoff to earth orbit. The third fluid cycles offer a very low risk, fully reusable, low operation cost alternative to high/variable mixture ratio bipropellant cycles. Variable mixture ratio engines with extendible nozzle are slightly lower performing than a single mixture ratio engine (MR = 7:1) with extendible nozzle. Dual expander engines (MR = 7:1) have slightly better performance than the single mixture ratio engine. Dual fuel dual expander engines offer a 16 percent improvement over the single mixture ratio engine.

Beichel, R.; Obrien, C. J.; Bair, E. K.

1988-01-01

315

Density Ratio Examples Semiparametric Statistical Formulation  

E-print Network

UMinformal Density Ratio Examples Semiparametric Statistical Formulation Combined semiparametric density estimators Semiparametric regression Application to Testicular Germ Cell Cancer Semiparametric Density Ratio Examples Semiparametric Statistical Formulation Combined semiparametric density estimators

Johnson, Raymond L.

316

Computation of Cold-Start Miss Ratios  

Microsoft Academic Search

Cold-start miss ratios are miss ratios that are measured with an initially empty first-level store. The values obtained depend on C, the first-level storage capacity, and on T, the number of references. These miss ratios, measured for various values of T, are useful in evaluating the effect of task switching on cache miss ratios when the cache capacity is C.

Malcolm C. Easton

1978-01-01

317

Learning About Ratios: A Sandwich Study  

NSDL National Science Digital Library

This lesson introduces students to the concept of ratio through a hands-on, delicious experiment. After an introductory activity where students identify the ratio of girls to boys in a group of 10 selected students, they create six different peanut butter and jelly sandwiches with different ingredient ratios to find which is the tastiest. Students then plan their own similar experiment using other concoctions which can be expressed in ratios.

Weinberg, Sheryl

1999-01-16

318

Transformer ratio improvement for beam based plasma accelerators  

NASA Astrophysics Data System (ADS)

Increasing the transformer ratio of wakefield accelerating systems improves the viability of present novel accelerating schemes. The use of asymmetric bunches to improve the transformer ratio of beam based plasma systems has been proposed for some time[1, 2] but suffered from lack appropriate beam creation systems. Recently these impediments have been overcome [3, 4] and the ability now exists to create bunches with current profiles shaped to overcome the symmetric beam limit of R ? 2. We present here work towards experiments designed to measure the transformer ratio of such beams, including theoretical models and simulations using VORPAL (a 3D capable PIC code) [5]. Specifically we discuss projects to be carried out in the quasi-nonlinear regime [6] at the UCLA Neptune Laboratory and the Accelerator Test Facility at Brookhaven National Lab.

O'Shea, Brendan; Rosenzweig, James; Barber, Samuel; Fukasawa, Atsushi; Williams, Oliver; Muggli, Patric; Yakimenko, Vitaly; Kusche, Karl

2012-12-01

319

Transformer ratio improvement for beam based plasma accelerators  

SciTech Connect

Increasing the transformer ratio of wakefield accelerating systems improves the viability of present novel accelerating schemes. The use of asymmetric bunches to improve the transformer ratio of beam based plasma systems has been proposed for some time[1, 2] but suffered from lack appropriate beam creation systems. Recently these impediments have been overcome [3, 4] and the ability now exists to create bunches with current profiles shaped to overcome the symmetric beam limit of R {<=} 2. We present here work towards experiments designed to measure the transformer ratio of such beams, including theoretical models and simulations using VORPAL (a 3D capable PIC code) [5]. Specifically we discuss projects to be carried out in the quasi-nonlinear regime [6] at the UCLA Neptune Laboratory and the Accelerator Test Facility at Brookhaven National Lab.

O'Shea, Brendan; Rosenzweig, James; Barber, Samuel; Fukasawa, Atsushi; Williams, Oliver; Muggli, Patric; Yakimenko, Vitaly; Kusche, Karl [University of California, Los Angeles, Department of Physics and Astronomy, Los Angeles, CA 90095 (United States); University of Southern California, Department of Electrical Engineering, Los Angeles, CA 90089 U.S.A. and Max-Planck-Institut fuer Physik, Foehringer Ring 6, 80805 Muenchen (Germany); Accelerator Test Facility, Brookhaven National Lab, Upton, NY, 11973 (United States)

2012-12-21

320

Spray Gun With Constant Mixing Ratio  

NASA Technical Reports Server (NTRS)

Conceptual mechanism mounted in handle of spray gun maintains constant ratio between volumetric flow rates in two channels leading to spray head. With mechanism, possible to keep flow ratio near 1:1 (or another desired ratio) over range of temperatures, orifice or channel sizes, or clogging conditions.

Simpson, William G.

1987-01-01

321

Bidding ratios to predict highway project costs  

Microsoft Academic Search

Purpose – Ratios were constructed using bidding data for highway construction projects in Texas to study whether there are useful patterns in project bids that are indicators of the project completion cost. The use of the ratios to improve predictions of completed project cost was studied. Design\\/methodology\\/approach – Ratios were calculated relating the second lowest bid, mean bid, and maximum

Trefor P. Williams

2005-01-01

322

A dynamic analysis of stock price ratios  

Microsoft Academic Search

Stock price ratios have long been used by finance practitioners as a relative value metric. A popular argument for this widespread use is that stock price ratios tend to revert to their long-run mean so that substantial deviations from historical averages could successfully be arbitraged away. In this work, we lay out the theoretical conditions for the ratio of stock

Antoine Giannetti; Ariel Viale

2011-01-01

323

High aspect ratio wrinkles via substrate prestretch.  

PubMed

A non-fractured, high aspect ratio wrinkled surface is successfully fabricated. Building upon recently developed models of the localization transition and the current knowledge of surface failures, the wrinkling mode is stabilized at high strain, doubling the accessible wrinkling aspect ratio to the currently reported value. This high aspect ratio surface provides significant promise for future wrinkle-based applications. PMID:24863587

Chen, Yu-Cheng; Crosby, Alfred J

2014-08-27

324

Gyromagnetic Ratios of Bound Particles  

E-print Network

A new approach to calculation of the binding corrections to the magnetic moments of the constituents in a loosely bound system, based on the Bargmann-Michel-Telegdi equation, is suggested. Binding corrections are calculated in this framework, and the results confirm earlier calculations performed by other methods. Our method clearly demonstrates independence of the binding corrections on the magnitude of the spin of the constituents.

Michael I. Eides; Howard Grotch

1997-03-24

325

Quantifying Void Ratio in Granular Materials Using Voronoi Tessellation  

NASA Technical Reports Server (NTRS)

Voronoi technique was used to calculate the local void ratio distribution of granular materials. It was implemented in an application-oriented image processing and analysis algorithm capable of extracting object edges, separating adjacent particles, obtaining the centroid of each particle, generating Voronoi polygons, and calculating the local void ratio. Details of the algorithm capabilities and features are presented. Verification calculations included performing manual digitization of synthetic images using Oda's method and Voronoi polygon system. The developed algorithm yielded very accurate measurements of the local void ratio distribution. Voronoi tessellation has the advantage, compared to Oda's method, of offering a well-defined polygon generation criterion that can be implemented in an algorithm to automatically calculate local void ratio of particulate materials.

Alshibli, Khalid A.; El-Saidany, Hany A.; Rose, M. Franklin (Technical Monitor)

2000-01-01

326

Directional spectral emissivity measurement system  

NASA Technical Reports Server (NTRS)

Apparatus and process for determining the emissivity of a test specimen including an integrated sphere having two concentric walls with a coolant circulating therebetween, and disposed within a chamber which may be under ambient, vacuum or inert gas conditions. A reference sample is disposed within the sphere with a monochromatic light source in optical alignment therewith. A pyrometer is in optical alignment with the test sample for obtaining continuous test sample temperature measurements during a test. An arcuate slit port is provided through the spaced concentric walls of the integrating sphere with a movable monochromatic light source extending through and movable along the arcuate slit port. A detector system extends through the integrating sphere for continuously detecting an integrated signal indicative of all radiation within its field of view, as a function of the emissivity of the test specimen at various temperatures and various angle position of the monochromatic light source. A furnace for heating the test sample to approximately 3000 K. and control mechanism for transferring the heated sample from the furnace to the test sample port in the integrating sphere is also contained within the chamber.

Halyo, Nesim (Inventor); Pandey, Dhirendra K. (Inventor)

1992-01-01

327

Neural correlates of the Pythagorean ratio rules.  

PubMed

Millennia ago Pythagoras noted a simple but remarkably powerful rule for the aesthetics of tone combinations: pairs of tones--intervals--with simple ratios such as an octave (ratio 2 : 1) or a fifth (ratio 3 : 2) were pleasant sounding (consonant), whereas intervals with complex ratios such as the major seventh (ratio 243 : 128) were harsh (dissonant). These Pythagorean ratio rules are the building blocks of Western classical music; however, their neurophysiologic basis is not known. Using functional MRI we have found the neurophysiologic correlates of the ratio rules. In musicians, the inferior frontal gyrus, superior temporal gyrus, medial frontal gyrus, inferior parietal lobule and anterior cingulate respond with progressively more activation to perfect consonances, imperfect consonances and dissonances. In nonmusicians only the right inferior frontal gyrus follows this pattern. PMID:17885594

Foss, Alexander H; Altschuler, Eric L; James, Karin H

2007-10-01

328

A leading edge heating array and a flat surface heating array: Final design. [for testing the thermal protection system of the space shuttle  

NASA Technical Reports Server (NTRS)

A heating array is described for testing full-scale sections of the leading edge and lower fuselage surfaces of the shuttle. The heating array was designed to provide a tool for development and acceptance testing of leading edge segments and large flat sections of the main body thermal protection system. The array was designed using a variable length module concept to meet test requirements using interchangeable components from one test configuration in another configuration. Heat generating modules and heat absorbing modules were employed to achieve the thermal gradient around the leading edge. A support was developed to hold the modules to form an envelope around a variety of leading edges; to supply coolant to each module; the support structure and to hold the modules in the flat surface heater configuration. An optical pyrometer system mounted within the array was designed to monitor specimen surface temperatures without altering the test article's surface.

1975-01-01

329

The Interstellar Rubidium Isotope Ratio toward ? Ophiuchi A  

NASA Astrophysics Data System (ADS)

The isotope ratio 85Rb/87Rb places constraints on models of the nucleosynthesis of heavy elements, but there is no precise determination of the ratio for material beyond the solar system. We report the first measurement of the interstellar Rb isotope ratio. Our measurement of the Rb I line at 7800 Å for the diffuse gas toward ? Oph A yields a value of 1.21+/-0.30 (1 ?) that differs significantly from the meteoritic value of 2.59. The Rb/K elemental abundance ratio for the cloud also is lower than that seen in meteorites. Comparison of the 85Rb/K and 87Rb/K ratios with meteoritic values indicates that the interstellar 85Rb abundance in this direction is lower than the solar system abundance. We attribute the lower abundance to a reduced contribution from the r-process. Interstellar abundances for Kr, Cd, and Sn are consistent with much less r-process synthesis for the solar neighborhood compared to the amount inferred for the solar system.

Federman, S. R.; Knauth, David C.; Lambert, David L.

2004-03-01

330

Indirect detection of nuclear spins of low gyromagnetic ratio coupled to spins of high gyromagnetic ratio  

SciTech Connect

In a heteronuclear system, the indirect detection of nuclei S, of weak gyromagnetic ratio, coupled to nuclei I, of strong gyromagnetic ratio, is accomplished by generation of zero and double quantum coherence between the I and S spin systems, during a preparatory period, TP. The zero and double quantum transitions are then interchanged at the midpoint of the evolution period, T1, producing an echo modulated only by S and I-I interactions at the end of the period T1, at which time the zero and double quantum coherence is then converted to I spin single quantum coherence yielding a free induction decay wave form S(T2) for given T1. The period, T1, is then varied to obtain a two-dimensional function S(T1, T2) which is then fully transformed to the frequency domain obtaining S(..omega..1,..omega..2) whereby the chemical shift of the coupled S spin is obtained along the ..omega..1 axis and the chemical shift of the I spin is obtained along the ..omega..2 axis.

Muller, L.

1980-12-09

331

Ecological genetics of sex ratios in plant populations.  

PubMed

In many angiosperm species, populations are reproductively subdivided into distinct sexual morphs including females, males and hermaphrodites. Sexual polymorphism is maintained by frequency-dependent selection, leading to predictable sex ratios at equilibrium. Charles Darwin devoted much of his book 'The Different Forms of Flowers on Plants of the Same Species' (1877) to investigating plant sexual polymorphisms and laid the foundation for many problems addressed today by integrating theory with empirical studies of the demography and genetics of populations. Here, we summarize our recent work on the ecological and genetic mechanisms influencing variation in sex ratios and their implications for evolutionary transitions among sexual systems. We present the results of a survey of sex ratios from 126 species from 47 angiosperm families and then address two general problems using examples from diverse angiosperm taxa: (i) the mechanisms governing biased sex ratios in dioecious species; (ii) the origins and maintenance of populations composed of females, males and hermaphrodites. Several themes are emphasized, including the importance of non-equilibrium conditions, the role of life history and demography in affecting sex ratios, the value of theory for modelling the dynamics of sex ratio variation, and the utility of genetic markers for investigating evolutionary processes in sexually polymorphic plant populations. PMID:20643745

Barrett, Spencer C H; Yakimowski, Sarah B; Field, David L; Pickup, Melinda

2010-08-27

332

Method of overriding ratio matching feature in power shift transmissions  

SciTech Connect

This patent describes a method of controlling the operation of a vehicle transmission operably connected to an engine and having clutches for selectively interconnecting an engine driven input drive shaft, an output drive shaft operatively coupled to ground engaging wheels of the vehicle to effect movement thereof over the ground, and gears rotatably housed in output drive shafts such that a selective engagement of the clutches will effect a varying of the speed of operation of the output shaft for a given speed of operation of the input shaft, the transmission further having en electrical control system including a microprocessor responsive to switches actuated by manual movement of a gearshift means between positions, including forward, reverse, and neutral positions, for controlling the clutches in the transmission, the microprocessor being operable to engage a ratio matching routine when the gearshift means is placed in the neutral position to select a gear having a gear ratio substantially equivalent to the ratio derived from the respective speeds of rotation of the input and output shafts. It comprises signaling the microprocessor for an upshift or a downshift of the transmission while engaged in the ratio matching routine; and exiting the ratio matching routine and entering a gear selection routine in the microprocessor while the gearshift remains in the neutral position to effect a selection of an alternative gear other than the gear selected by the ratio matching routine.

Bulgrien, G.H.

1991-04-16

333

Eccentric crank variable compression ratio mechanism  

DOEpatents

A variable compression ratio mechanism for an internal combustion engine that has an engine block and a crankshaft is disclosed. The variable compression ratio mechanism has a plurality of eccentric disks configured to support the crankshaft. Each of the plurality of eccentric disks has at least one cylindrical portion annularly surrounded by the engine block. The variable compression ratio mechanism also has at least one actuator configured to rotate the plurality of eccentric disks.

Lawrence, Keith Edward (Kobe, JP); Moser, William Elliott (Peoria, IL); Roozenboom, Stephan Donald (Washington, IL); Knox, Kevin Jay (Peoria, IL)

2008-05-13

334

Queens versus workers: sex-ratio conflict in eusocial Hymenoptera  

Microsoft Academic Search

Studies of sex-ratio conflict in the eusocial Hymenoptera (ants, bees and wasps) have provided the most rigorous tests of kin selection theory. The hymenopteran haplodiploid system of sex determination generally renders workers more closely related to their sisters than to their brothers, whereas queens are equally related to their sons and daughters. Kin selection theory therefore predicts that resource allocation

Natasha J. Mehdiabadi; Hudson Kern Reeve; Ulrich G. Mueller

2003-01-01

335

Gravitational waves from extreme mass-ratio inspirals  

NASA Astrophysics Data System (ADS)

Extreme mass-ratio inspiral (EMRI) is the main target of Laser Interferometer Space Antenna (LISA). We give a short review on this system as test-bench of general relativity. We briefly mention the recent progress in our study to obtain sufficiently accurate gravitational waveforms from this type of inspiralling binaries.

Tanaka, T.

2008-07-01

336

Binary Communication with Large Bandwidth to IF Frequency Ratios  

Microsoft Academic Search

The effect of I F filter bandwidth to I F frequency ratio on the probability of error in a binary bandpass communication system with nonreturn-to-zero (NRZ) and split-phase (SP) signals is investigated. ed. Explicit results are given for the case when the bandpas I F filter is transformed from a single-pole low-pass filter.

I. Korn; M. Namet

1975-01-01

337

Fabrication of extreme aspect ratio wires within photonic crystal fibers  

Microsoft Academic Search

We have recently fabricated continuous semiconducting micro and nanowires within the empty spaces of highly ordered microstructured (e.g., photonic crystal or holey) optical fibers (MOF's). These systems contain the highest aspect ratio semiconductor micro- and nanowires yet produced by any method: centimeters long and ~100 nm in diameter. These structures combine the flexible light guiding capabilities of an optical fiber

J. V. Badding; P. J. A. Sazio; A. Amezcua Correa; T. J. Scheidemantel; C. E. Finlayson; N. F. Baril; D.-J. Won; H. Fang; B. Jackson; A. Borhan; V. Gopalan

2005-01-01

338

The landau-placzek ratio for multicomponent fluids  

Microsoft Academic Search

Under the assumption that the coupling between the sound modes and modes associated with heat and mass diffusion can be neglected, an expression for the Landau-Placzek ratio for multicomponent fluids is derived using thermodynamic fluctuation theory. Applications of the general formula to ternary systems are discussed briefly

H. N. W. Lekkerkerker; W. G. Laidlaw

1972-01-01

339

Cross contamination in dual inlet isotope ratio mass spectrometers  

Microsoft Academic Search

Since the early days of geochemical isotope ratio mass spectrometry there has always been the problem of cross contamination, i.e. the contamination of the sample gas with traces of reference gas (and vice versa) in a dual inlet system and the analyzer itself. This was attributable to valve leakages and could be corrected for. In modern leak-free machines this problem

H. A. J. Meijer; R. E. M. Neubert; G. H. Visser

2000-01-01

340

Sex ratio at birth in Croatia: update.  

PubMed

There is strong evidence that the sex ratio at birth is partially determined by environmental and social factors. The modern change in those factors serves as an explanation for the secular decline in sex ratio at birth in most of the industrialized countries. This article is the reexamination of the results from my previous communication in which no trend in sex ratio at birth was established for the Croatian data from 1946 to 2007. The data for the years 2008 to 2011 were added, which didn't result with the detection of a significant change in sex ratio at birth by the regression analysis or by the Box-Jenkins time series analysis. Although the numerous factors associated with the decline in sex ratio at birth did occur during the studied period (e.g. increased exposure to the environmental pollution through food, air and water, the rise of the obesity and diabetes incidence, the economic crisis etc.), it appears that none of them made the measurable impact on sex ratio at birth. Also, the possible marginally significant decline in sex ratio at birth could be the result of a high sex ratio at birth immediately after the World War II. The results of this study caution against rapid generalization of the factors found to influence the sex ratio at birth in the epidemiological and clinical studies on the population level data. PMID:25144988

Pavi?, Dario

2014-06-01

341

Why ratio dependence is (still) a bad model of predation.  

PubMed

The history of the idea that predation rates are functions of the ratio of prey density to predator density, known as ratio dependence, is reviewed and updated. When the term was introduced in 1989, it was already known that higher predator abundance often reduced an individual predator's average intake rate of prey. However, the idea that this effect was a universally applicable inverse proportionality was new. That idea was widely criticized in many articles in the early 1990s, and many of these criticisms have never been addressed. Nevertheless, ratio dependence seems to be gaining in popularity and is the subject of a recent monograph by the originators. This article revisits the most important objections to this theory, and assesses to what extent they have been answered by the theory's proponents. In this process, several new objections are raised. The counterarguments begin with the lack of a plausible, generally applicable mechanism that could produce ratio dependence. They include the fact that ratio dependence is a special case of predator-density effects, which, in turn, are only one of many non-prey species effects that influence the consumption rate of a particular prey. The proclaimed simplicity advantage of ratio dependence is at best small and is outweighed by its disadvantages; it predicts biologically implausible phenomena, and cannot easily be extended to describe multi-species systems, trait-mediated interactions, coevolution, and a number of other important ecological phenomena. Any potential small simplicity advantage disappears with corrections to remove unrealistic low-density dynamics caused by ratio dependence. The frequent occurrence of strong predator dependence does not make ratio dependence a better 'default' model of predation than prey dependence, and empirical studies of the full range of non-prey species effects on the consumption rates of predators are needed. PMID:25099654

Abrams, Peter A

2014-08-01

342

Double Stage Heat Transformer Controlled by Flow Ratio  

Microsoft Academic Search

\\u000a this paper shows the values of Flow ratio (FR) for control of an absorption double stage heat transformer. The main parameters\\u000a for the heat pump system are defined as COP, FR and GTL. The control of the entire system is based in a new definition of\\u000a FR. The heat balance of the Double Stage Heat Transformer (DSHT) is used for

S. Silva-Sotelo; R. J. Romero

343

On the Calibration of Likelihood Ratios  

E-print Network

in Forensic Sciences #12;Likelihood Ratios (LR) in Forensic Science Given two materials to compare Evidence;Outline Likelihood Ratio (LR) Framework in Forensic Science Assessing LR Performance C lib ti f LR l a suspect... Relevant hypotheses (at source level) Hypothesis p : materials come from the same source

Autonoma de Madrid, Universidad

344

The Divine Ratio and Golden Rectangles.  

ERIC Educational Resources Information Center

The material examines aspects of Fibonacci and Lucas sequences, the generation of the Divine Ratio, and the nature of this ratio in golden rectangles, triangles, and figures made up of golden triangles. It is noted Lucas sequence is formed like Fibonacci but has one and three as the first elements. (Author/MP)

Cooper, Martin

1982-01-01

345

The Golden Ratio--A Contrary Viewpoint  

ERIC Educational Resources Information Center

Many assertions about the occurrence of the golden ratio phi in art, architecture, and nature have been shown to be false, unsupported, or misleading. For instance, we show that the spirals found in sea shells, in particular the "Nautilus pompilius," are not in the shape of the golden ratio, as is often claimed. Some of the most interesting…

Falbo, Clement

2005-01-01

346

Economy Track: Employment to Population Ratio  

NSDL National Science Digital Library

Time plot compares the employment-population ratio - the broadest measure of people who are working in America. Allows to compare between recessions, also allows to compare between demographic groups -- by sex, race/ethnicity and educational attainment. Also shows the secular trend for employment-population ratio since 1973.

Institute, Economic P.

347

Georgia Tech Profiling Overconsolidation Ratio in  

E-print Network

Georgia Tech Profiling Overconsolidation Ratio in Clays by Piezocone and Flat Dilatometer Tests Properties: M = 6 sin'/(3-sin') ' = effective stress friction angle Cc = compression index Cs = swelling Clay Chamber Tests 0 200 400 600 800 1000 1200 0 10 20 30 40 Overconsolidation Ratio, OCR Depth

Mayne, Paul W.

348

Momentum subtraction and the R-ratio  

E-print Network

We determine the R-ratio for massless quarks in several renormalization schemes to various loop orders. These are the momentum subtraction schemes of Celmaster and Gonsalves as well as the minimal momentum subtraction scheme. The dependence of the R-ratio on the schemes is analysed.

J. A. Gracey

2014-10-24

349

HIT RATIO OF DYNAMICALLY PROGRAMMABLE CACHE  

Microsoft Academic Search

Dynamically Programmable Cache is a Reconfigurable Cache designed for General Purpose Microprocessor with multimedia applications. This paper evaluates the performance of DPC as a coprocessor accelerator with FPGA fabric integrated on it. DPC stores its FPGA configurations in the cache, which may affect the hit\\/miss ratio of this cache. This paper shows small effect induced on the miss ratio due

Mouna Nakkar

2004-01-01

350

Effects of Thermal Conductivity Ratio in  

E-print Network

Effects of Thermal Conductivity Ratio in Helium-Cooled Divertors B. H. Mills J. D. Rader D. L conductivity ratio Verify previous predictions of thermal performance at prototypical conditions and general But He has higher thermal conductivity k Matching Re not sufficient for similarity Multi

351

The Gyromagnetic Ratios of the Ferromagnetic Elements  

Microsoft Academic Search

The gyromagnetic ratios for the three ferromagnetic elements have been determined by means of a technique involving a sensitive torsional pendulum. The final values obtained, in terms of the mass-to-charge ratio of the electron, are: iron 1.028+\\/-0.001 cobalt 1.068+\\/-0.004 and nickel 1.078+\\/-0.002.

G. G. Scott

1952-01-01

352

Measurement of the ? ? ?? decay branching ratio  

Microsoft Academic Search

We have measured the branching ratio for the radiative decay ? ? ?? with ? mesons produced in antiproton-proton annihilation at rest into ?0? and ??. Taking into account ? - ? mixing we find a branching ratio B(? ? ??) = (6.6 ± 1.7) × 10?4, in accord with the constructive interference solution in other experiments. The upper-limit for

A. Abele; J. Adomeit; C. Amsler; C. A. Baker; B. M. Barnett; C. J. Batty; M. Benayoun; A. Berdoz; K. Beuchert; S. Bischoff; P. Blüm; K. Braune; D. V. Bugg; T. Case; A. Cooper; O. Cramer; K. M. Crowe; V. Credé; T. Degener; N. Djaoshvili; S. v. Dombrowski; M. Doser; W. Dünnweber; A. Ehmanns; D. Engelhardt; M. A. Faessler; P. Giarritta; R. Hackmann; R. P. Haddock; F. H. Heinsius; M. Heinzelmann; M. Herz; N. P. Hessey; P. Hidas; C. Hodd; C. Holtzhaußen; D. Jamnik; H. Kalinowsky; B. Kalteyer; B. Kämmle; P. Kammel; J. Kisiel; E. Klempt; H. Koch; C. Kolo; U. Kurilla; M. Kunze; M. Lakata; R. Landua; J. Lüdemann; H. Matthäy; R. McCrady; J. Meier; C. A. Meyer; L. Montanet; R. Ouared; F. Ould-Saada; K. Peters; B. Pick; C. Pietra; C. N. Pinder; M. Ratajczak; C. Regenfus; S. Resag; W. Roethel; P. Schmidt; I. Scott; R. Seibert; S. Spanier; H. Stöck; C. Straßburger; U. Strohbusch; M. Suffert; U. Thoma; M. Tischhäuser; C. Völcker; S. Wallis; D. Walther; U. Wiedner; B. S. Zou

1997-01-01

353

Osmosis and Surface Area to Volume Ratio.  

ERIC Educational Resources Information Center

Describes an experiment designed to help students understand the concepts of osmosis and surface area to volume ratio (SA:VOL). The task for students is to compare water uptake in different sizes of potato cubes and relate differences to their SA:VOL ratios. (JN)

Barrett, D. R. B.

1984-01-01

354

Student Learning Centre Ratio and Proportion  

E-print Network

Student Learning Centre 1 of 2 Ratio and Proportion A ratio compares the sizes of two quantities. A proportion describes the relationship of a part to the whole. Example 1 In a laboratory class of students of students in the class is 40 so the proportion or fractional share of males in the class is 16 40 2 5

355

CCSSM Challenge: Graphing Ratio and Proportion  

ERIC Educational Resources Information Center

A renewed emphasis was placed on ratio and proportional reasoning in the middle grades in the Common Core State Standards for Mathematics (CCSSM). The expectation for students includes the ability to not only compute and then compare and interpret the results of computations in context but also interpret ratios and proportions as they are…

Kastberg, Signe E.; D'Ambrosio, Beatriz S.; Lynch-Davis, Kathleen; Mintos, Alexia; Krawczyk, Kathryn

2013-01-01

356

Ratio model serves suprathreshold color luminance discrimination  

E-print Network

Ratio model serves suprathreshold color­ luminance discrimination Marcel J. Sankeralli and Kathy T the responses of the three postreceptoral mechanisms are combined to subserve discrimination of suprathreshold model of suprathreshold color­luminance dis- crimination, in which discrimination depends on a ratio

Mullen, Kathy T.

357

Empirical Analysis of Drill Ratio Research  

ERIC Educational Resources Information Center

Providing students an appropriate level of challenge, called the instructional level, is an important component of effective instruction. Research regarding the optimal ratio of known to unknown items for drill tasks has been inconsistent. The author of the current article conducted an empirical metaanalysis of research on drill ratios by using…

Burns, M.K.

2004-01-01

358

Hybrid LTA vehicle controllability as affected by buoyancy ratio  

NASA Technical Reports Server (NTRS)

The zero and low speed controllability of heavy lift airships under various wind conditions as affected by the buoyancy ratio are investigated. A series of three hybrid LTA vehicls were examined, each having a dynamic thrust system comprised of four H-34 helicopters, but with buoyant envelopes of different volumes (and hence buoyancies), and with varying percentage of helium inflation and varying useful loads (hence gross weights). Buoyancy ratio, B, was thus examined varying from approximately 0.44 to 1.39. For values of B greater than 1.0, the dynamic thrusters must supply negative thrust (i.e. downward).

Meyers, D. N.; Kubicki, P.; Tarczynski, T.; Fairbanks, A.; Piasecki, F. N.

1979-01-01

359

High Transformer ratios in collinear wakefield accelerators.  

SciTech Connect

Based on our previous experiment that successfully demonstrated wakefield transformer ratio enhancement in a 13.625 GHz dielectric-loaded collinear wakefield accelerator using the ramped bunch train technique, we present here a redesigned experimental scheme for even higher enhancement of the efficiency of this accelerator. Design of a collinear wakefield device with a transformer ratio R2, is presented. Using a ramped bunch train (RBT) rather than a single drive bunch, the enhanced transformer ratio (ETR) technique is able to increase the transformer ratio R above the ordinary limit of 2. To match the wavelength of the fundamental mode of the wakefield with the bunch length (sigmaz=2 mm) of the new Argonne wakefield accelerator (AWA) drive gun (where the experiment will be performed), a 26.625 GHz dielectric based accelerating structure is required. This transformer ratio enhancement technique based on our dielectric-loaded waveguide design will result in a compact, high efficiency accelerating structures for future wakefield accelerators.

Power, J. G.; Conde, M.; Yusof, Z.; Gai, W.; Jing, C.; Kanreykin, A.; Schoessow, P.; High Energy Physics; Euclid Techlabs, LLC

2008-01-01

360

Scavenging ratios based on inflow air concentrations  

SciTech Connect

Scavenging ratios were calculated from field measurements made during April 1985. Event precipitation samples were collected at the surface, but air chemistry measurements in the air mass feeding the precipitation were made from an aircraft. In contrast, ratios calculated in previous studies have used air concentration and precipitation chemistry data from only surface measurements. Average scavenging ratios were calculated for SO{sub 4}{sup 2{minus}}, NO{sub 3}{sup {minus}}, NH{sub 4}{sup +}, total sulfate, total nitrate, and total ammonium for 5 events; the geometric mean of these scavenging ratios were 8.5 {times} 10{sup 5}, 5.6 {times} 10{sup 6}, 4.3 {times} 10{sup 5}, 3.4 {times} 10{sup 5}, 2.4 {times} 10{sup 6}, and 9.7 {times} 10{sup 4}, respectively. These means are similar to but less variable than previous ratios formed using only surface data.

Davis, W.E.; Dana, M.T.; Lee, R.N.; Slinn, W.G.N.; Thorp, J.M.

1991-07-01

361

Detailed measurements of equivalence ratio modulations in premixed flames using laser Rayleigh scattering and absorption spectroscopy  

Microsoft Academic Search

Equivalence ratio non-uniformities may give rise to some of the instabilities observed in modern lean premixed combustion\\u000a systems. The present work intends to investigate the influence of equivalence ratio perturbations on the dynamics of premixed\\u000a flames. A burner equipped with a secondary injection system is used to generate equivalence ratio perturbations which are\\u000a convected by the flow and impinge on

Heiner Schwarz; Laurent Zimmer; Daniel Durox; Sébastien Candel

2010-01-01

362

The Charon-Pluto mass ratio from MKO astrometry  

NASA Technical Reports Server (NTRS)

Using the University of Hawaii (UH) 2.2-m telescope, we obtained charge coupled device (CCD) images of Pluto as it passed through a single field of 10 stars during 6 nights of Charon's 6.4-day orbital period. From these data, Charon's orbital semimajor axis is found to be 19,460 +/- 58 km, which is consistent with the recent measurement by Null et al. (1993), of 19,405 +/- 86 km. Our semimajor axis implies a system mass of (14.32 +/- 0.13) x 10(exp 24) g. From the motions of Pluto and Charon around their barycenter, we find that the ratio of Charon's mass to Pluto's is 0.1566 +/- 0.0035, indicating that the bodies both have densities near 2 g/cc. Our ratio is nearly twice that of Null et al., who find a ratio of 0.0837 +/- 0.0147. Possible reasons for the large discrepancy are discussed.

Young, L. A.; Olkin, C. B.; Elliot, J. L.; Tholen, D. J.; Buie, M. W.

1994-01-01

363

CALIPSO lidar ratio retrieval over the ocean.  

PubMed

We are demonstrating on a few cases the capability of CALIPSO to retrieve the 532 nm lidar ratio over the ocean when CloudSat surface scattering cross section is used as a constraint. We are presenting the algorithm used and comparisons with the column lidar ratio retrieved by the NASA airborne high spectral resolution lidar. For the three cases presented here, the agreement is fairly good. The average CALIPSO 532 nm column lidar ratio bias is 13.7% relative to HSRL, and the relative standard deviation is 13.6%. Considering the natural variability of aerosol microphysical properties, this level of accuracy is significant since the lidar ratio is a good indicator of aerosol types. We are discussing dependencies of the accuracy of retrieved aerosol lidar ratio on atmospheric aerosol homogeneity, lidar signal to noise ratio, and errors in the optical depth retrievals. We are obtaining the best result (bias 7% and standard deviation around 6%) for a nighttime case with a relatively constant lidar ratio (in the vertical) indicative of homogeneous aerosol type. PMID:21935239

Josset, Damien; Rogers, Raymond; Pelon, Jacques; Hu, Yongxiang; Liu, Zhaoyan; Omar, Ali; Zhai, Peng-Wang

2011-09-12

364

CALIPSO Lidar Ratio Retrieval Over the Ocean  

NASA Technical Reports Server (NTRS)

We are demonstrating on a few cases the capability of CALIPSO to retrieve the 532 nm lidar ratio over the ocean when CloudSat surface scattering cross section is used as a constraint. We are presenting the algorithm used and comparisons with the column lidar ratio retrieved by the NASA airborne high spectral resolution lidar. For the three cases presented here, the agreement is fairly good. The average CALIPSO 532 nm column lidar ratio bias is 13.7% relative to HSRL, and the relative standard deviation is 13.6%. Considering the natural variability of aerosol microphysical properties, this level of accuracy is significant since the lidar ratio is a good indicator of aerosol types. We are discussing dependencies of the accuracy of retrieved aerosol lidar ratio on atmospheric aerosol homogeneity, lidar signal to noise ratio, and errors in the optical depth retrievals. We are obtaining the best result (bias 7% and standard deviation around 6%) for a nighttime case with a relatively constant lidar ratio (in the vertical) indicative of homogeneous aerosol type

Josset, Damien B.; Rogers, Raymond R.; Pelon, Jacques; Hu, Yongxiang; Liu, Zhaoyan; Omar, Ali H.; Zhai, Peng-Wang

2011-01-01

365

The effect of SiO2/Al2O3 ratio on the structure and microstructure of the glazes from SiO2-Al2O3-CaO-MgO-Na2O-K2O system  

NASA Astrophysics Data System (ADS)

Ceramic glazes are commonly used to covering of the facing surface of ceramics ware. A well-chosen oxide composition and firing conditions of glazes causes significant improvement of technical parameters of ceramic products. Modern glazes are classified as glass-ceramic composites with different crystalline phases arising during firing. The presence of crystals in the glass matrix is influenced by many factors, especially by oxides molar composition. A crucial role is played by the molar ratio of SiO2/Al2O3. In this work the six composition of glazes from SiO2-Al2O3-CaO-MgO-Na2O-K2O system were examined. The only variable is the ratio of the silicon oxideto alumina at a constant content of other components: MgO, CaO, K2O, Na2O, ZnO. In order to determine the real phase composition of the obtained glazes research on fluorescence spectrometer (XRF) were done. For structural studies X-ray diffraction (XRD) and spectroscopic in the middle infrared (MIR) were performed. In order to determine the state of the surface (microstructure) research on the scanning electron microscope (SEM) with EDX. The research allowed to determine the influence of SiO2/Al2O3 ratio on the structure and phase composition of glazes and the nature, and type of formed crystalline phases.

Partyka, Janusz; Sitarz, Maciej; Le?niak, Magdalena; Gasek, Katarzyna; Jele?, Piotr

2015-01-01

366

Musical Ratios in Sounds from the Human Cochlea  

PubMed Central

The physiological roots of music perception are a matter of long-lasting debate. Recently light on this problem has been shed by the study of otoacoustic emissions (OAEs), which are weak sounds generated by the inner ear following acoustic stimulation and, sometimes, even spontaneously. In the present study, a high-resolution time–frequency method called matching pursuit was applied to the OAEs recorded from the ears of 45 normal volunteers so that the component frequencies, amplitudes, latencies, and time-spans could be accurately determined. The method allowed us to find that, for each ear, the OAEs consisted of characteristic frequency patterns that we call resonant modes. Here we demonstrate that, on average, the frequency ratios of the resonant modes from all the cochleas studied possessed small integer ratios. The ratios are the same as those found by Pythagoras as being most musically pleasant and which form the basis of the Just tuning system. The statistical significance of the results was verified against a random distribution of ratios. As an explanatory model, there are attractive features in a recent theory that represents the cochlea as a surface acoustic wave resonator; in this situation the spacing between the rows of hearing receptors can create resonant cavities of defined lengths. By adjusting the geometry and the lengths of the resonant cavities, it is possible to generate the preferred frequency ratios we have found here. We conclude that musical perception might be related to specific geometrical and physiological properties of the cochlea. PMID:22655092

Blinowska, Katarzyna J.; Kwaskiewicz, Konrad; Jedrzejczak, W. Wiktor; Skarzynski, Henryk

2012-01-01

367

Musical ratios in sounds from the human cochlea.  

PubMed

The physiological roots of music perception are a matter of long-lasting debate. Recently light on this problem has been shed by the study of otoacoustic emissions (OAEs), which are weak sounds generated by the inner ear following acoustic stimulation and, sometimes, even spontaneously. In the present study, a high-resolution time-frequency method called matching pursuit was applied to the OAEs recorded from the ears of 45 normal volunteers so that the component frequencies, amplitudes, latencies, and time-spans could be accurately determined. The method allowed us to find that, for each ear, the OAEs consisted of characteristic frequency patterns that we call resonant modes. Here we demonstrate that, on average, the frequency ratios of the resonant modes from all the cochleas studied possessed small integer ratios. The ratios are the same as those found by Pythagoras as being most musically pleasant and which form the basis of the Just tuning system. The statistical significance of the results was verified against a random distribution of ratios. As an explanatory model, there are attractive features in a recent theory that represents the cochlea as a surface acoustic wave resonator; in this situation the spacing between the rows of hearing receptors can create resonant cavities of defined lengths. By adjusting the geometry and the lengths of the resonant cavities, it is possible to generate the preferred frequency ratios we have found here. We conclude that musical perception might be related to specific geometrical and physiological properties of the cochlea. PMID:22655092

Blinowska, Katarzyna J; Kwaskiewicz, Konrad; Jedrzejczak, W Wiktor; Skarzynski, Henryk

2012-01-01

368

Retrieved waste properties and high-level waste critical component ratios for privatization waste feed delivery  

SciTech Connect

The purpose for this document is to provide the basis for the retrieved waste properties and high-level waste critical component ratios specified in the System Specification for the Double-Shell Tank System.

Peters, B.B.

1998-03-04

369

Optimal sampling ratios in comparative diagnostic trials  

PubMed Central

Summary A subjective sampling ratio between the case and the control groups is not always an efficient choice to maximize the power or to minimize the total required sample size in comparative diagnostic trials.We derive explicit expressions for an optimal sampling ratio based on a common variance structure shared by several existing summary statistics of the receiver operating characteristic curve. We propose a two-stage procedure to estimate adaptively the optimal ratio without pilot data. We investigate the properties of the proposed method through theoretical proofs, extensive simulation studies and a real example in cancer diagnostic studies. PMID:24948841

Dong, Ting; Tang, Liansheng Larry; Rosenberger, William F.

2014-01-01

370

Optimizing an irreversible Diesel cycle — fine tuning of compression ratio and cut-off ratio  

Microsoft Academic Search

A simplified irreversible model has been proposed for the air standard Diesel cycle. Global thermal and friction losses have been lumped into an equivalent friction term. Optimization of the cycle has been performed for power output as well as for thermal efficiency with respect to compression ratio and cut-off ratio. The optimum values of these ratios compare well with standard

Souvik Bhattacharyya

2000-01-01

371

Ratio and Proportion A ratio compares the sizes of two quantities. A proportion describes the relationship  

E-print Network

Ratio and Proportion A ratio compares the sizes of two quantities. A proportion describes in the class is 16+24 = 40 so the proportion or fractional share of males in the class is 16 40 2 5 and the proportion of females in the class is 24 40 3 5 Note that the ratio of males to females is equivalent

372

The Effect of Satellite Galaxies on Gravitational Lensing Flux Ratios  

E-print Network

Gravitational lenses with anomalous flux ratios are often cited as possible evidence for dark matter satellites predicted by simulations of hierarchical merging in cold dark matter cosmogonies. We show that the fraction of quads with anomalous flux ratios depends primarily on the total mass and spatial extent of the satellites, and the characteristic lengthscale R of their distribution. If R is 100 kpc, then for a moderately elliptical galaxy with a line-of-sight velocity dispersion of 250 km/s, a mass of 3 x 10^9 solar masses in highly-concentrated (Plummer model) satellites is needed for 20% of quadruplets to show anomalous flux ratios, rising to 1.25 x 10^10 solar masses for 50%. Several times these masses are required if the satellites have more extended Hernquist profiles. Compared to a typical elliptical, the flux ratios of quads formed by typical edge-on disc galaxies with maximum discs are significantly less susceptible to changes through substructure -- three times the mass in satellite galaxies is needed to affect 50% of the systems. In many of the lens systems with anomalous flux ratios, there is evidence for visible satellites (e.g., B2045+265 or MG0414+0534). We show that optically identified substructure should not be preponderant among lens systems with anomalies. There are two possible resolutions of this difficulty. First, in some cases, visible substructure may be projected within or close to the Einstein radius and wrongly ascribed as the culprit, whereas dark matter substructure is causing the flux anomaly. Second, bright satellites, in which baryon cooling and condensation has taken place, may have higher central densities than dark satellites, rendering them more efficient at causing flux anomalies.

E. M. Shin; N. W. Evans

2008-01-15

373

Science Application of Area and Ratio Concepts  

ERIC Educational Resources Information Center

This article describes using area and ratio concepts to examine why some animals, or people wearing different types of shoes, sink into the surface on which they are standing. Students compute "sinking values" to explain these differences. (Contains 2 figures.)

Horak, Virginia M.

2006-01-01

374

Gyromagnetic ratio of a black hole  

SciTech Connect

We examine the properties of a rotating loop of charged matter in the presence of a static charged black hole. The behavior of the gyromagnetic ratio is examined in the limit as the radius of the loop becomes very large and in the limit as the loop radius approaches the radius of the black hole's event horizon. The implications of these results for the gyromagnetic ratio of a black hole are discussed. For large radii of the loop the gyromagnetic ratio reduces to the value computed for a loop in classical electromagnetism, which has {ital g}=1. As the radius of the loop approaches the horizon, the ratio approaches that for a black hole which has {ital g}=2, like an electron. The latter result is also true for a {ital neutral} loop; hence, magnetic-monopole black holes that accrete matter with angular momentum have gravitationally induced electric fields.

Garfinkle, D. (University of California, Santa Barbara, CA (USA). Department of Physics); Traschen, J. (University of Massachusetts, Amherst, MA (USA). Department of Physics and Astronomy)

1990-07-15

375

Oxidative ratio (OR) of UK peats  

NASA Astrophysics Data System (ADS)

The oxidative ratio (OR) is the amount of CO2 sequestered in the terrestrial biosphere for each mol of O2 produced. The OR governs the effectiveness of a terrestrial biome to mitigate the impact of anthropogenic CO2 emissions and it has been used to calculate the balance of terrestrial and oceanic carbon sinks across the globe. However, few studies have investigated the controls of the variability in OR. What factors affect OR - climate? Soil type? Vegetation type? N deposition? Land use? Land use change? Small shifts in OR could have important implications in the global partitioning of CO2 between the atmosphere, biosphere, and oceans. This study looks at peat soils (Histosols) from a series of sites representing a climatic transect across the UK. Duplicate peat cores were taken, along with samples of above-ground vegetation and litter, from sites in northern Scotland (Forsinard), southern Scotland (Auchencorth), northern England (Moor House; Thorne Moor) through the Welsh borders (Whixhall Moss) and Somerset levels (Westhay Moor) to Dartmoor and Bodmin Moor in the south west of England. Sub-samples of the cores were analysed for their CHNO concentrations using a Costech ECS 4010 Elemental combustion system. Using the method of Masiello et al. (2008), OR values could be calculated from these elemental concentrations. Initial results show that OR values of UK peats varied between 0.94 and 1.1 with a median value of 1.05 which similar to the median value of World soils but the range is at the more reduced end. There was significant variation between peat cores, even between peat cores on the same site and the peat showed significant reduction in OR with depth in the core.

Clay, G. D.; Worrall, F.; Masiello, C. A.

2012-04-01

376

Analysis of Ratios in Multivariate Morphometry  

PubMed Central

The analysis of ratios of body measurements is deeply ingrained in the taxonomic literature. Whether for plants or animals, certain ratios are commonly indicated in identification keys, diagnoses, and descriptions. They often provide the only means for separation of cryptic species that mostly lack distinguishing qualitative characters. Additionally, they provide an obvious way to study differences in body proportions, as ratios reflect geometric shape differences. However, when it comes to multivariate analysis of body measurements, for instance, with linear discriminant analysis (LDA) or principal component analysis (PCA), interpretation using body ratios is difficult. Both techniques are commonly applied for separating similar taxa or for exploring the structure of variation, respectively, and require standardized raw or log-transformed variables as input. Here, we develop statistical procedures for the analysis of body ratios in a consistent multivariate statistical framework. In particular, we present algorithms adapted to LDA and PCA that allow the interpretation of numerical results in terms of body proportions. We first introduce a method called the “LDA ratio extractor,” which reveals the best ratios for separation of two or more groups with the help of discriminant analysis. We also provide measures for deciding how much of the total differences between individuals or groups of individuals is due to size and how much is due to shape. The second method, a graphical tool called the “PCA ratio spectrum,” aims at the interpretation of principal components in terms of body ratios. Based on a similar idea, the “allometry ratio spectrum” is developed which can be used for studying the allometric behavior of ratios. Because size can be defined in different ways, we discuss several concepts of size. Central to this discussion is Jolicoeur's multivariate generalization of the allometry equation, a concept that was derived only with a heuristic argument. Here we present a statistical derivation of the allometric size vector using the method of least squares. The application of the above methods is extensively demonstrated using published data sets from parasitic wasps and rock crabs. PMID:21828084

Baur, Hannes; Leuenberger, Christoph

2011-01-01

377

Posterior odds ratios for selected regression hypotheses  

Microsoft Academic Search

Summary  Bayesian posterior odds ratios for frequently encountered hypotheses about parameters of the normal linear multiple regression\\u000a model are derived and discussed. For the particular prior distributions utilized, it is found that the posterior odds ratios\\u000a can be well approximated by functions that are monotonic in usual sampling theoryF statistics. Some implications of this finding and the relation of our work

A. Zellner; A. Siow

1980-01-01

378

Measurement of the ?-->?? decay branching ratio  

NASA Astrophysics Data System (ADS)

We have measured the branching ratio for the radiative decay ?-->?? with ? mesons produced in antiproton-proton annihilation at rest into ?0? and ??. Taking into account ?-? mixing we find a branching ratio B(?-->??)=(6.6+/-1.7)x10-4, in accord with the constructive interference solution in other experiments. The upper-limit for the direct radiative decay ?-->3? is 1.9x10-4 at 95% confidence level.

Crystal Barrel Collaboration; Abele, A.; Adomeit, J.; Amsler, C.; Baker, C. A.; Barnett, B. M.; Batty, C. J.; Benayoun, M.; Berdoz, A.; Beuchert, K.; Bischoff, S.; Blüm, P.; Braune, K.; Bugg, D. V.; Case, T.; Cooper, A.; Cramer, O.; Crowe, K. M.; Credé, V.; Degener, T.; Djaoshvili, N.; Dombrowski, S. V.; Doser, M.; Dünnweber, W.; Ehmanns, A.; Engelhardt, D.; Faessler, M. A.; Giarritta, P.; Hackmann, R.; Haddock, R. P.; Heinsius, F. H.; Heinzelmann, M.; Herz, M.; Hessey, N. P.; Hidas, P.; Hodd, C.; Holtzhaußen, C.; Jamnik, D.; Kalinowsky, H.; Kalteyer, B.; Kämmle, B.; Kammel, P.; Kisiel, J.; Klempt, E.; Koch, H.; Kolo, C.; Kurilla, U.; Kunze, M.; Lakata, M.; Landua, R.; Lüdemann, J.; Matthäy, H.; McCrady, R.; Meier, J.; Meyer, C. A.; Montanet, L.; Ouared, R.; Ould-Saada, F.; Peters, K.; Pick, B.; Pietra, C.; Pinder, C. N.; Ratajczak, M.; Regenfus, C.; Resag, S.; Roethel, W.; Schmidt, P.; Scott, I.; Seibert, R.; Spanier, S.; Stöck, H.; Straßburger, C.; Strohbusch, U.; Suffert, M.; Thoma, U.; Tischhäuser, M.; Völcker, C.; Wallis, S.; Walther, D.; Wiedner, U.; Zou, B. S.

1997-10-01

379

Approaches to high aspect ratio triangulations  

NASA Technical Reports Server (NTRS)

In aerospace computational fluid dynamics calculations, high aspect ratio, or stretched, triangulations are necessary to adequately resolve the features of a viscous flow around bodies. In this paper, we explore alternatives to the Delaunay triangulation which can be used to generate high aspect ratio triangulations of point sets. The method is based on a variation of the lifting map concept which derives Delaunay triangulations from convex hull calculations.

Posenau, M.-A.

1993-01-01

380

Plutonium isotope ratio variations in North America  

SciTech Connect

Historically, approximately 12,000 TBq of plutonium was distributed throughout the global biosphere by thermo nuclear weapons testing. The resultant global plutonium fallout is a complex mixture whose {sup 240}Pu/{sup 239}Pu atom ratio is a function of the design and yield of the devices tested. The average {sup 240}Pu/{sup 239}Pu atom ratio in global fallout is 0.176 + 014. However, the {sup 240}Pu/{sup 239}Pu atom ratio at any location may differ significantly from 0.176. Plutonium has also been released by discharges and accidents associated with the commercial and weapons related nuclear industries. At many locations contributions from this plutonium significantly alters the {sup 240}Pu/{sup 239}Pu atom ratios from those observed in global fallout. We have measured the {sup 240}Pu/{sup 239}Pu atom ratios in environmental samples collected from many locations in North America. This presentation will summarize the analytical results from these measurements. Special emphasis will be placed on interpretation of the significance of the {sup 240}Pu/{sup 239}Pu atom ratios measured in environmental samples collected in the Arctic and in the western portions of the United States.

Steiner, Robert E [Los Alamos National Laboratory; La Mont, Stephen P [Los Alamos National Laboratory; Eisele, William F [Los Alamos National Laboratory; Fresquez, Philip R [Los Alamos National Laboratory; Mc Naughton, Michael [Los Alamos National Laboratory; Whicker, Jeffrey J [Los Alamos National Laboratory

2010-12-14

381

Energy Distribution Ratio into Micro EDM Electrodes  

NASA Astrophysics Data System (ADS)

Energy distribution ratio into micro EDM electrodes was determined based on the summation between the ratio of energy loss due to heat conduction within electrodes and ratio of energy carried away by debris. Ratio of energy loss due to heat conduction was obtained by comparing the measured and calculated temperature rise on electrode after igniting plural pulses discharges. On the other hand, the ratio of energy carried away by debris was calculated based on the measured removal volume. Energy distribution ratio into micro EDM anode and cathode was between 10% and 15% in total which was comparatively lower than that of macro EDM. This is because much larger fraction of the total discharge energy is consumed for the generation and enthalphy increase of the plasma in the early stage of discharge. Besides, unlike macro EDM the energy carried away by debris in micro EDM cannot be ignored compared with the energy lost due to heat conduction. This means, the energy consumption by material removal in micro EDM with regard to the energy distributed into the electrodes is more efficient compared to that of macro EDM.

Zahiruddin, Mohd; Kunieda, Masanori

382

Experimental evaluation of blockage ratio and plenum evacuation system flow effects on pressure distribution for bodies of revolution in 0.1 scale model test section of NASA Lewis Research Center's proposed altitude wind tunnel  

NASA Technical Reports Server (NTRS)

An experimental investigation was conducted in the slotted test section of the 0.1-scale model of the proposed Altitude Wind Tunnel to evaluate wall interference effects at tunnel Mach numbers from 0.70 to 0.95 on bodies of revolution with blockage rates of 0.43, 3, 6, and 12 percent. The amount of flow that had to be removed from the plenum chamber (which surrounded the slotted test section) by the plenum evacuation system (PES) to eliminate wall interference effects was determined. The effectiveness of tunnel reentry flaps in removing flow from the plenum chamber was examined. The 0.43-percent blockage model was the only one free of wall interference effects with no PES flow. Surface pressures on the forward part of the other models were greater than interference-free results and were not influenced by PES flow. Interference-free results were achieved on the aft part of the 3- and 6-percent blockage models with the proper amount of PES flow. The required PES flow was substantially reduced by opening the reentry flaps.

Burley, Richard R.; Harrington, Douglas E.

1987-01-01

383

Development of a Micropyrolyzer for Enhanced Isotope Ratio Measurement  

SciTech Connect

This paper presents design, fabrication and testing of a micro scale reactor for the pyrolysis of organic compounds. The reactor system described here is suitable for use in enhanced isotope ratio measurement in a continuous flow mode. A characteristic of such a system is it can be utilized to pyrolyze organic compounds with sample size 20-50 times smaller than conventional. Results have shown that organic compounds, such as 1-butanol, ethanol, and ethanol amine, can be fully decomposed to desired products CO and H2, at temperature of 1200oC, which is 200oC lower than conventionally reported. Undesired products methane and CO2 are eliminated in the pyrolysis process. The proof-of-concept experimental results clearly demonstrate that the micro pyrolyzer can be readily integrated with isotope ratio mass spectrometer (IRMS) to differentiate between different sources of the same materials.

Hu, Jianli; Dagle, Robert A.; Johnson, Bradley R.; Kreuzer, Helen W.; Gaspar, Daniel J.; Roberts, Benjamin Q.; Alexander, M. L.

2008-11-19

384

Anyons with anomalous gyromagnetic ratio and the Hall effect  

Microsoft Academic Search

Letting the mass depend on the spin-field coupling as M2=m2?(eg\\/2c2)F??S??, we propose a new set of relativistic planar equations of motion for spinning anyons. Our model can accommodate any gyromagnetic ratio g and provides us with a novel version of the Bargmann–Michel–Telegdi equations in 2+1 dimensions. The system becomes singular when the field takes a critical value, and, for g?2,

C. Duval; P. A. Horváthy

2004-01-01

385

Anyons with anomalous gyromagnetic ratio & the Hall effect  

E-print Network

Letting the mass depend on the spin-field coupling as $M^2=m^2-(eg/2c^2)F_{\\alpha\\beta}S^{\\alpha\\beta}$, we propose a new set of relativistic planar equations of motion for spinning anyons. Our model can accommodate any gyromagnetic ratio $g$ and provides us with a novel version of the Bargmann-Michel-Telegdi equations in 2+1 dimensions. The system becomes singular when the field takes a critical value, and, for $g\

C. Duval; P. A. Horvathy

2004-02-24

386

A method to calculate ratios among QCD condensates  

Microsoft Academic Search

A new method to calculate condensates from independent experimental data is presented. We use quotients of different moments of Laplace sum rules in the form of a system of linear equations where the unknowns are the ratios of condensates. We obtain for the gluon condensate the value (pi\\/3) = (0.050 +\\/- 0.015), which is 25% bigger than the standard one

V. Giménez; J. Bordes; J. Peñarrocha

1991-01-01

387

Using shadowing ratios to evaluate data assimilation techniques  

NASA Astrophysics Data System (ADS)

Identifying successful "noise reduction" as such remains a challenge in applications where the "true" values are not know a priori (and linear noise reduction is a game not a true task). We suggest shadowing ratios as a measure of noise reduction when the task at hand involves prediction. Initial condition uncertainty will more or less always limit the lead time of a chaotic model, even when that model reproduces the system dynamics perfectly. Since in reality, observations from such systems tend to be clouded by measurement error, the maximum lead time we can expect to accurately predict using the model will be short. Data assimilation techniques attempt to improve our state estimates, we introduce a new measure which allows us to estimate the quality of these techniques. A model trajectory shadows for as long as it is consistent with the noise model of the observed states. We define the shadowing ratio as the ratio of the length of time the model shadows using the assimilated initial conditions to the length of time the model shadows using some reference data assimilation technique. We use the measure to evaluate the effectiveness of one assimilation technique in particular, Gradient Descent of Indeterminism (GDI). Using the Moore-Spiegel system as an example we first use shadowing ratios to show the effect of using different numbers of observations from the past when applying GDI. We then compare GDI to other assimilation techniques using the measure to compare the effectiveness from a forecasting perspective. Finally, since GDI requires derivative information from the system, we compare the effectiveness of the algorithm when using the exact derivative matrix and when approximating using a forward difference technique. Other aspects of GDI are discussed, in the context of filtering and noise reduction.

Wheatcroft, E.; Smith, L. A.

2012-04-01

388

On derivation of the analytical expression for damping ratios in a low-viscosity approximation  

NASA Astrophysics Data System (ADS)

The damping ratios of waves and oscillations in nonlinear dispersion equations are found for planar, cylindrical, and spherical geometries as applied to finite-volume liquids. For a cylindrical jet and a plane interface between viscous liquids, the damping ratios are determined for the first time. When the radius of curvature of the liquid jet surface decreases, so does the damping ratio of capillary waves. In a system of immiscible liquids, the damping ratio may be both larger and smaller than that for the pure liquid depending on the viscosity of the liquids and the ratio of their densities. This is because the damping ratio depends on the kinematic viscosities of pure liquids. The damping ratio is also estimated for waves arising at the liquidgas interface due to a tangential discontinuity of the velocity field.

Grigor'ev, A. I.; Shiryaeva, S. O.

2013-10-01

389

Accretion disc dynamics in extreme mass ratio compact binaries  

E-print Network

An analysis is presented of a numerical investigation of the dynamics and geometry of accretion discs in binary systems with mass ratios q < 0.1, applicable to ultra-compact X-ray binaries, AM CVn stars and very short period cataclysmic variables. The steady-state geometry of the disc in the binary reference frame is found to be quite different from that expected at higher mass ratios. For q ~ 0.1, the disc takes on the usual elliptical shape, with the major axis aligned perpendicular to the line of centres of the two stars. However, at smaller mass ratios the elliptical gaseous orbits in the outer regions of the disc are rotated in the binary plane. The angle of rotation increases with gas temperature, but is found to vary inversely with q. At q = 0.01, the major axis of these orbits is aligned almost parallel to the line of centres of the two stars. These effects may be responsible for the similar disc structure inferred from Doppler tomography of the AM CVn star GP Com (Morales-Rueda et al. 2003), which has q = 0.02. The steady-state geometry at low mass ratios is not predicted by an inviscid, restricted three-body model of gaseous orbits; it is related to the effects of tidal-viscous truncation of the disc near the Roche lobe boundary. Since the disc geometry can be inferred observationally for some systems, it is proposed that this may offer a useful diagnostic for the determination of mass ratios in ultra-compact binaries.

Michael Truss

2007-01-02

390

Study of signal-to-noise ratio in digital mammography  

NASA Astrophysics Data System (ADS)

Mammography techniques have recently advanced from those using analog systems (the screen-film system) to those using digital systems; for example, computed radiography (CR) and flat-panel detectors (FPDs) are nowadays used in mammography. Further, phase contrast mammography (PCM)-a digital technique by which images with a magnification of 1.75× can be obtained-is now available in the market. We studied the effect of the air gap in PCM and evaluated the effectiveness of an antiscatter x-ray grid in conventional mammography (CM) by measuring the scatter fraction ratio (SFR) and relative signal-to-noise ratio (rSNR) and comparing them between PCM and the digital CM. The results indicated that the SFRs for the CM images obtained with a grid were the lowest and that these ratios were almost the same as those for the PCM images. In contrast, the rSNRs for the PCM images were the highest, which means that the scattering of x-rays was sufficiently reduced by the air gap without the loss of primary x-rays.

Kato, Yuri; Fujita, Naotoshi; Kodera, Yoshie

2009-02-01

391

On the carbon and nitrogen isotope abundance ratios in Comet Halley  

NASA Astrophysics Data System (ADS)

Emission lines attributable to (C-13)(N-14) have been resolved in ground-based spectra of Comet Halley. An analysis of the spectrum using six (C-13)(N-14) lines results in a carbon isotope abundance ratio, (C-12)(C-13) = 63 + 9/-7, and a lower limit N-14/N-15 greater than 200. The carbon isotope ratio is nearly 3-delta less than the bulk solar system ratio, 89. The limit on the nitrogen isotope ratio is consistent with the bulk solar system ratio, 250. The carbon isotope ratio in the comet may be explained by selective fractionation enhancement of C-13 in the parent of the CN molecule, or by a depletion of C-12 relative to C-13.

Wyckoff, S.; Lindholm, E.

392

Trigonometry: Comparing Ratio and Unit Circle Methods  

E-print Network

Before the 1960s, introductory trigonometry was taught in Victorian schools using the ratio method, where trigonometric functions are defined as ratios of sides of right angled triangles. With the advent of "new maths", the unit circle method was introduced. This study explored differences between the two methods for teaching introductory trigonometry. Eight. classes of students were randomly allocated to either teaching method. The ratio method was found to be much more effective, resulting in better performance and retention in trigonometry and algebra, and more favourable attitudes. Two methods of introducing trigonometry Since the advent of the "new mathematics", two methods of teaching introductory trigonometry have been used in Victorian schools. For decades, introductory trigonometry had been taught to Year 9 and 10 students (average age 14 and 15) by the ratio method. In this method, the trigonometric functions are defined as the ratios of pairs of sides in a right angled triangle. From the early 1960s, an alternative "modern " method was advocated by some educationalists (Trende, 1962; Willis, 1967) as a more desirable

Margaret Kendal; Kaye Stacey

393

A new ratio for protocol categorization.  

PubMed

The present review describes and validates a new ratio "S" created for matching predictability and balance between TP and TN. Validity of S was studied in a three-step process as follows: (i) S was applied to the data of a past study predicting cardiac output response to fluid bolus from response to passive leg raise (PLR); (ii) S was comparatively analyzed with traditional ratios by modeling different 2 ? 2 contingency tables in 1000 hypothetical patients; (iii) precision of S was compared with other ratios by computing random fluctuations in the same patients. In comparison to other ratios, S performs better in predicting the cardiac response to fluid bolus and supports more directly the clinical conclusions. When the proportion of false responses is high, S is close to the coefficient correlation (CC). When the proportion of true responses is high, S is the unique ratio that identifies the categorization that balances the proportion of TP and TN. The precision of S is close to that of CC. In conclusion, S should be considered for creating categories from quantitative variables; especially when matching predictability with balance between TP and TN is a concern. PMID:24738007

Squara, Pierre

2014-01-01

394

Utilizing Isotopic Uranium Ratios in Groundwater Evaluations at NFSS  

SciTech Connect

The U.S. Army Corps of Engineers (USACE) Buffalo District is currently evaluating environmental contamination at the Niagara Falls Storage Site (NFSS) under the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) as part of its Formerly Utilized Sites Remedial Action Program (FUSRAP). The NFSS is located in the Town of Lewiston in western New York and has been used to store uranium-contaminated materials since 1944. Most of the radioactive materials are currently contained in an on-site structure, but past contamination remains in soil and groundwater. As a naturally occurring radionuclide, uranium is present in all groundwater. Because contamination levels at the site are quite low, it can be difficult to distinguish zones that have been impacted by the past releases from those at the high end of the natural background range. The differences in the isotopic ratio of uranium-234 (U-234) to uranium-238 (U-238) between natural groundwater systems and affected areas are being used in an innovative way to better define the nature and extent of groundwater contamination at NFSS. In natural groundwater, the ratio of U-234 to U-238 exceeds 1 due to the alpha particle recoil effect, in which U-234 is preferentially mobilized to groundwater from adjacent rock or soil. This process is very slow, and it can be hundreds to thousands of years before a measurable impact is seen in the isotopic ratio. Thus, as a result of the recoil effect, the ratio of U-234 to U-238 will be higher in natural groundwater than in contaminated groundwater. This means that if site releases were the source of the uranium being measured in groundwater at NFSS, the ratio of U-234 to U-238 would be expected to be very close to 1 (the same ratio that exists in wastes and soil at the site), because not enough time has elapsed for the alpha particle recoil effect to have significantly altered that ratio. From an evaluation of site and regional groundwater data, an isotopic ratio of 1.2 has been identified as a site-specific signature to help distinguish natural groundwater (e.g., at the high end of the background range) from zones impacted by past releases. This information is crucial for focusing the ongoing CERCLA evaluation and decision making process. This signature value is not applied as a bright line, e.g., to define samples with ratios of U-234 to U-238 above 1.2 as representing background and those with ratios below 1.2 as being affected by site releases. Rather, this ratio serves as a weight of evidence for use in conjunction with other site information, including historical activities, to form science-based decisions regarding contaminated groundwater. This novel approach for developing a groundwater signature from the isotopic uranium ratio has proven to be a very useful tool for NFSS, and it is now being considered for broader application. (authors)

Rhodes, M.C.; Keil, K.G.; Frederick, W.T.; Papura, T.R.; Leithner, J.S. [U.S. Army Corps of Engineers, Buffalo District, 1776 Niagara Street, Buffalo, NY 14207 (United States); Peterson, J.M.; MacDonell, M.M. [Argonne National Laboratory, Environmental Science Division, 9700 South Cass Avenue, Building 900, Argonne, IL 60439 (United States)

2006-07-01

395

Kinship Institutions and Sex Ratios in India  

PubMed Central

This article explores the relationship between kinship institutions and sex ratios in India at the turn of the twentieth century. Because kinship rules vary by caste, language, religion, and region, we construct sex ratios by these categories at the district level by using data from the 1901 Census of India for Punjab (North), Bengal (East), and Madras (South). We find that the male-to-female sex ratio varied positively with caste rank, fell as one moved from the North to the East and then to the South, was higher for Hindus than for Muslims, and was higher for northern Indo-Aryan speakers than for the southern Dravidian-speaking people. We argue that these systematic patterns in the data are consistent with variations in the institution of family, kinship, and inheritance. PMID:21308567

CHAKRABORTY, TANIKA; KIM, SUKKOO

2010-01-01

396

Magnetostrictive contribution to Poisson ratio of galfenol  

NASA Astrophysics Data System (ADS)

In this work we present a detailed study on the magnetostrictive contribution to Poisson ratio for samples under applied mechanical stress. Magnetic contributions to strain and Poisson ratio for cubic materials were derived by accounting elastic and magneto-elastic anisotropy contributions. We apply our theoretical results for a material of interest in magnetomechanics, namely, galfenol (Fe1-xGax). Our results show that there is a non-negligible magnetic contribution in the linear portion of the curve of stress versus strain. The rotation of the magnetization towards [110] crystallographic direction upon application of mechanical stress leads to an auxetic behavior, i.e., exhibiting Poisson ratio with negative values. This magnetic contribution to auxetic behavior provides a novel insight for the discussion of theoretical and experimental developments of materials that display unusual mechanical properties.

Paes, V. Z. C.; Mosca, D. H.

2013-09-01

397

Algorithms for high aspect ratio oriented triangulations  

NASA Technical Reports Server (NTRS)

Grid generation plays an integral part in the solution of computational fluid dynamics problems for aerodynamics applications. A major difficulty with standard structured grid generation, which produces quadrilateral (or hexahedral) elements with implicit connectivity, has been the requirement for a great deal of human intervention in developing grids around complex configurations. This has led to investigations into unstructured grids with explicit connectivities, which are primarily composed of triangular (or tetrahedral) elements, although other subdivisions of convex cells may be used. The existence of large gradients in the solution of aerodynamic problems may be exploited to reduce the computational effort by using high aspect ratio elements in high gradient regions. However, the heuristic approaches currently in use do not adequately address this need for high aspect ratio unstructured grids. High aspect ratio triangulations very often produce the large angles that are to be avoided. Point generation techniques based on contour or front generation are judged to be the most promising in terms of being able to handle complicated multiple body objects, with this technique lending itself well to adaptivity. The eventual goal encompasses several phases: first, a partitioning phase, in which the Voronoi diagram of a set of points and line segments (the input set) will be generated to partition the input domain; second, a contour generation phase in which body-conforming contours are used to subdivide the partition further as well as introduce the foundation for aspect ratio control, and; third, a Steiner triangulation phase in which points are added to the partition to enable triangulation while controlling angle bounds and aspect ratio. This provides a combination of the advancing front/contour techniques and refinement. By using a front, aspect ratio can be better controlled. By using refinement, bounds on angles can be maintained, while attempting to minimize the number of Steiner points.

Posenau, Mary-Anne K.

1995-01-01

398

Enantiomer Ratios of Meteoritic Sugar Derivatives  

NASA Technical Reports Server (NTRS)

Carbonaceous meteorites contain a diverse suite of soluble organic compounds. Studies of these compounds reveal the Solar System's earliest organic chemistry. Among the classes of organic compounds found in meteorites are keto acids (pyruvic acid, etc.), hydroxy tricarboxylic acids (1), amino acids, amides, purines and pyrimidines. The Murchison and Murray meteorites are the most studied for soluble and insoluble organic compounds and organic carbon phases. The majority of (indigenous) meteoritic compounds are racemic, (i.e., their D/L enantiomer ratios are 50:50). However, some of the more unusual (non-protein) amino acids contain slightly more of one enantiomer (usually the L) than the other. This presentation focuses on the enantiomer analyses of three to six-carbon (3C to 6C) meteoritic sugar acids. The molecular and enantiomer analysis of corresponding sugar alcohols will also be discussed. Detailed analytical procedures for sugar-acid enantiomers have been described. Results of several meteorite analyses show that glyceric acid is consistently racemic (or nearly so) as expected of non-biological mechanisms of synthesis. Also racemic are 4-C deoxy sugar acids: 2-methyl glyceric acid; 2,4-dihydroxybutyric acid; 2,3-dihydroxybutyric acid (two diastereomers); and 3,4-dihydroxybutyric acid. However, a 4C acid, threonic acid, has never been observed as racemic, i.e., it possesses a large D excess. In several samples of Murchison and one of GRA 95229 (possibly the most pristine carbonaceous meteorite yet analyzed) threonic acid has nearly the same D enrichment. In Murchison, preliminary isotopic measurements of individual threonic acid enantiomers point towards extraterrestrial sources of the D enrichment. Enantiomer analyses of the 5C mono-sugar acids, ribonic, arabinonic, xylonic, and lyxonic also show large D excesses. It is worth noting that all four of these acids (all of the possible straight-chained 5C sugar acids) are present in meteorites, including the rare lyxonic acid, and their relative abundances are in equilibrium proportions. In addition (in contrast to the above D-only excesses), some of the above acids are found in biology as the L enantiomer. Whether rare are common, all of the 6C sugar acids that are present in sufficient amounts to allow enantiomer analysis (Mannonic, gluconic, altronic, talonic, idonic, gulonic, and galactonic) also, apparently, possess significant D excesses.

Cooper, George

2012-01-01

399

On the variability of alligator sex ratios  

USGS Publications Warehouse

Samples of alligators from wild and 'farm' populations exhibited disproportionate sex ratios. Males predominated among young alligators from wild populations, whereas females were much more abundant than males in the farm population, where resources were superabundant. These results and other considerations lead us to hypothesize that environmental factors influence sex determination in alligators. During favorable environmental conditions natural selection is expected to favor a preponderance of the sex whose individuals exhibit the greater environmentally associated variation in relative fitness. We hypothesize that environmentally associated variation in age at sexual maturity of females produces sufficient variation in relative fitness of females to result in selection for low sex ratios during periods of resource abundance.

Nichols, J.D.; Chabreck, R.H.

1980-01-01

400

Secular trends in newborn sex ratios.  

PubMed

A wide variety of factors have been shown to influence the male to female ratio at birth, which invariably displays a male excess. This paper will review and amplify recent work by the author, with specific references to individual countries, regions and entire continents in order to provide a global overview of this subject. It will be shown that stress, including stress related to political events, influences this ratio. Man-made radiation is also shown to have played a significant role in relation to the Windscale fire (1957) and Chernobyl (1986). PMID:25219502

Grech, Victor

2014-11-01

401

Radioactive anomaly discrimination from spectral ratios  

DOEpatents

A method for discriminating a radioactive anomaly from naturally occurring radioactive materials includes detecting a first number of gamma photons having energies in a first range of energy values within a predetermined period of time and detecting a second number of gamma photons having energies in a second range of energy values within the predetermined period of time. The method further includes determining, in a controller, a ratio of the first number of gamma photons having energies in the first range and the second number of gamma photons having energies in the second range, and determining that a radioactive anomaly is present when the ratio exceeds a threshold value.

Maniscalco, James; Sjoden, Glenn; Chapman, Mac Clements

2013-08-20

402

Laser Ultrasonic System for On-Line Steel Tube Gauging  

NASA Astrophysics Data System (ADS)

A laser-ultrasonic system has been installed on a seamless tubing production line of The Timken Company and is being used to measure on-line the wall thickness of tubes during processing. The seamless process consists essentially in forcing a mandrel through a hot cylindrical billet in rotation and typically results in fairly large wall thickness variations that should be minimized and controlled to respect specifications. The system includes a Q-switched Nd-YAG laser for generation of ultrasound by ablation, a long pulse very stable Nd-YAG laser for detection coupled to a confocal Fabry-Perot interferometer, a pyrometer to measure tube temperature and two laser Doppler velocimeters to measure the coordinates of the probing location at the tube surface. The laser, data acquisition and processing units are housed in a cabin off line and connected to a front coupling head located over the passing tube by optical fibers. The system has been integrated into the plant computer network and provides in real time thickness data to the plant operators. It allow much faster mill setups, has been used since its deployment for inspecting more than 100,000 tubes and has demonstrated very significant savings.

Monchalin, Jean-Pierre; Choquet, Marc; Padioleau, Christian; Néron, Christian; Lévesque, Daniel; Blouin, Alain; Corbeil, Christian; Talbot, Richard; Bendada, Abdelhakim; Lamontagne, Mario; Kolarik, Robert V.; Jeskey, Gerald V.; Dominik, Erich D.; Duly, Larry J.; Samblanet, Kenneth J.; Agger, Steven E.; Roush, Kenneth J.; Mester, Michael L.

2003-03-01

403

Mantel-Haenszel odds ratio and Peto's log odds ratio under the general framework of combining CDs  

E-print Network

Mantel-Haenszel odds ratio and Peto's log odds ratio under the general framework of combining CDs ratio is a special case of combining aCDs and Peto's log odds ratio can also be derived using(1 - p1) . · Objects of interest: odds ratio , log odds ratio = ln . 2. Mantel-Haenszel and Peto methods

Xie, Minge

404

Wide acceptance angle, high concentration ratio, optical collector  

NASA Technical Reports Server (NTRS)

The invention is directed to an optical collector requiring a wide acceptance angle, and a high concentration ratio. The invention is particularly adapted for use in solar collectors of cassegrain design. The optical collector system includes a parabolic circular concave primary mirror and a hyperbolic circular convex secondary mirror. The primary mirror includes a circular hole located at its center wherein a solar collector is located. The mirrored surface of the secondary mirror has three distinct zones: a center circle, an on-axis annulus, and an off-axis section. The parabolic shape of the primary mirror is chosen so that the primary mirror reflects light entering the system on-axis onto the on-axis annulus. A substantial amount of light entering the system off-axis is reflected by the primary mirror onto either the off-axis section or onto the center circle. Subsequently, the off-axis sections reflect the off-axis light toward the solar collector. Thus, off-axis light is captured which would otherwise be lost to the system. The novelty of the system appears to lie in the configuration of the primary mirror which focuses off-axis light onto an annular portion of the secondary mirror to enable capture thereof. This feature results in wide acceptance angle and a high concentration ratio, and also compensates for the effects of non-specular reflection, and enables a cassegrain configuration to be used where such characteristics are required.

Kruer, Mark Arthur (inventor)

1990-01-01

405

Efficiency Ratios and Community Bank Performance  

Microsoft Academic Search

This study develops a multivariate discriminant model to differentiate between low efficiency and high efficiency community banks (less than $1 billion in total assets) based upon the efficiency ratio, a commonly used financial performance measure that relates non-interest expenses to total operating income. The model includes proxies for the banking regulatory CAMELS rating variables including: the equity capital to total

Fred H. Hays; Arthur H. Gilbert

406

Flowmeter determines mix ratio for viscous adhesives  

NASA Technical Reports Server (NTRS)

Flowmeter determines mix ratio for continuous flow mixing machine used to produce an adhesive from a high viscosity resin and aliphatic amine hardener pumped through separate lines to a rotary blender. The flowmeter uses strain gages in the two flow paths and monitors their outputs with appropriate instrumentation.

Lemons, C. R.

1967-01-01

407

Ratios exaggerate gender differences in mathematical ability  

Microsoft Academic Search

Comments on J. C. Stanley and C. P. Benbow's assertion concerning gender differences in the distribution of SAT-M scores. The present author contends that if an emphasis on group differences minimizes the magnitude of gender differences, then an emphasis on ratio can only exaggerate such differences.

Joseph S. Rossi

1983-01-01

408

Do Credit Spreads Reflect Stationary Leverage Ratios?  

Microsoft Academic Search

Most structural models of default preclude the firm from altering its capital structure. In practice, firms adjust outstanding debt levels in response to changes in firm value, thus generating mean-reverting leverage ratios. We propose a structural model of default with stochastic interest rates that captures this mean reversion. Our model generates credit spreads that are larger for low-leverage firms, and

Pierre Collin-Dufresne; Robert S. Goldstein

2001-01-01

409

Preprocessing Text to Improve Compression Ratios  

Microsoft Academic Search

Summary form only given. We discuss the use of a text preprocessing algorithm that can improve the compression ratio of standard data compression algorithms, in particular `bzip2', when used on text files, by up to 20%. The text preprocessing algorithm uses a static dictionary of the English language that is kept separately from the compressed file. The method in which

Holger Kruse; Amar Mukherjee

1998-01-01

410

Compression ratio effect on methane HCCI combustion  

SciTech Connect

The authors have used the HCT (hydrodynamics, chemistry, and transport) chemical kinetics code to simulate HCCI (homogeneous charge compression ignition) combustion of methane-air mixtures. HCT is applied to explore the ignition timing, burn duration, NO{sub X}production, gross indicated efficiency and gross IMEP of a supercharged engine (3 atm. intake pressure) with 14:1, 16:1 and 18:1 compression ratios at 1200 rpm. HCT has been modified to incorporate the effect of heat transfer and to calculate the temperature that results from mixing the recycled exhaust with the fresh mixture. This study uses a single reaction zone that varies as a function of crank angle. The ignition process is controlled by adjusting the intake equivalence ratio and the residual gas trapping (RGT). RGT is internal exhaust gas recirculation, which recycles both thermal energy and combustion product species. Adjustment of equivalence ratio and RGT is accomplished by varying the timing of the exhaust valve closure in either two-stroke or four-stroke engines. Inlet manifold temperature is held constant at 300 K. Results show that, for each compression ratio, there is a range of operational conditions that show promise of achieving the control necessary to vary power output while keeping indicated efficiency above 50 percent and NO{sub X}levels below 100 ppm. HCT results are also compared with a set of recent experimental data for natural gas.

Aceves, S.M.; Smith, J.R.; Westbrook, C.K.; Pitz, W.J. [Lawrence Livermore National Lab., CA (United States)

1999-07-01

411

Compression ratio effect on methane HCCI combustion  

SciTech Connect

We have used the HCT (Hydrodynamics, Chemistry and Transport) chemical kinetics code to simulate HCCI (homogeneous charge compression ignition) combustion of methane-air mixtures. HCT is applied to explore the ignition timing, bum duration, NOx production, gross indicated efficiency and gross IMEP of a supercharged engine (3 atm. Intake pressure) with 14:1, 16:l and 18:1 compression ratios at 1200 rpm. HCT has been modified to incorporate the effect of heat transfer and to calculate the temperature that results from mixing the recycled exhaust with the fresh mixture. This study uses a single control volume reaction zone that varies as a function of crank angle. The ignition process is controlled by adjusting the intake equivalence ratio and the residual gas trapping (RGT). RGT is internal exhaust gas recirculation which recycles both thermal energy and combustion product species. Adjustment of equivalence ratio and RGT is accomplished by varying the timing of the exhaust valve closure in either 2-stroke or 4-stroke engines. Inlet manifold temperature is held constant at 300 K. Results show that, for each compression ratio, there is a range of operational conditions that show promise of achieving the control necessary to vary power output while keeping indicated efficiency above 50% and NOx levels below 100 ppm. HCT results are also compared with a set of recent experimental data for natural gas.

Aceves, S. M.; Pitz, W.; Smith, J. R.; Westbrook, C.

1998-09-29

412

Disproportionate sex ratios of wolf pups  

USGS Publications Warehouse

Males comprised 66 percent of wild wolf (Canis lupus) pups from a saturated, high-density wolf range in northeastern Minnesota, possibly reflecting disproportionate conception of males. Packs from areas of lower wolf density in other areas of Minnesota had equal sex ratios of pups or a disproportionate number of female pups. Captive wolves showed a slight preponderance of male pups.

Mech, L.D.

1975-01-01

413

Gyromagnetic ratio of a black hole  

Microsoft Academic Search

We examine the properties of a rotating loop of charged matter in the presence of a static charged black hole. The behavior of the gyromagnetic ratio is examined in the limit as the radius of the loop becomes very large and in the limit as the loop radius approaches the radius of the black hole's event horizon. The implications of

David Garfinkle; Jennie Traschen

1990-01-01

414

Viscosity to entropy ratio at extremality  

E-print Network

Assuming gauge theory realization at the boundary, we show that the viscosity to entropy ratio is 1/(4 pi) where the bulk is represented by a large class of extremal black holes in anti-de Sitter space. In particular, this class includes multiple R-charged black holes in various dimensions.

Sayan K. Chakrabarti; Sachin Jain; Sudipta Mukherji

2010-01-19

415

Female-predominant sex ratios in angiosperms  

Microsoft Academic Search

A model is presented which expresses the seed production of dioecious and gynodioecious animal-pollinated Angiosperms in terms of the relative seed-fecundity of the sexes, the number of pollinator visits to each flower and the sex ratio. The model predicts that the maximum seed set occurs when females predominate, providing the pollinators visit each flower more than once and the seed

David G Lloyd

1974-01-01

416

Giving More Realistic Definitions of Trigonometric Ratios  

ERIC Educational Resources Information Center

Trigonometry is a well known branch of Mathematics. The study of trigonometry is of great importance in surveying, astronomy, navigation, engineering, and in different branches of science. This paper reports on the discovery of flaws in the traditional definitions of trigonometric ratios of an angle, which (in most cases) make use of the most…

Bhattacharjee, Pramode Ranjan

2012-01-01

417

High-aspect ratio magnetic nanocomposite polymer cilium  

NASA Astrophysics Data System (ADS)

This paper presents a new fabrication technique to achieve ultra high-aspect ratio artificial cilia micro-patterned from flexible highly magnetic rare earth nanoparticle-doped polymers. We have developed a simple, inexpensive and scalable fabrication method to create cilia structures that can be actuated by miniature electromagnets, that are suitable to be used for lab-on-a chip (LOC) and micro-total-analysis-system (?-TAS) applications such as mixers and flow-control elements. The magnetic cilia are fabricated and magnetically polarized directly in microfluidic channels or reaction chambers, allowing for easy integration with complex microfluidic systems. These cilia structures can be combined on a single chip with other microfluidic components employing the same permanently magnetic nano-composite polymer (MNCP), such as valves or pumps. Rare earth permanent magnetic powder, (Nd0.7Ce0.3)10.5Fe83.9B5.6, is used to dope polydimethylsiloxane (PDMS), resulting in a highly flexible M-NCP of much higher magnetization and remanence [1] than ferromagnetic polymers typically employed in magnetic microfluidics. Sacrificial poly(ethylene-glycol) (PEG) is used to mold the highly magnetic polymer into ultra high-aspect ratio artificial cilia. Cilia structures with aspect ratio exceeding 8:0.13 can be easily fabricated using this technique and are actuated using miniature electromagnets to achieve a high range of motion/vibration.

Rahbar, M.; Tseng, H. Y.; Gray, B. L.

2014-03-01

418

Neuroprotective Sirtuin ratio reversed by ApoE4.  

PubMed

The canonical pathogenesis of Alzheimer's disease links the expression of apolipoprotein E ?4 allele (ApoE) to amyloid precursor protein (APP) processing and A? peptide accumulation by a set of mechanisms that is incompletely defined. The development of a simple system that focuses not on a single variable but on multiple factors and pathways would be valuable both for dissecting the underlying mechanisms and for identifying candidate therapeutics. Here we show that, although both ApoE3 and ApoE4 associate with APP with nanomolar affinities, only ApoE4 significantly (i) reduces the ratio of soluble amyloid precursor protein alpha (sAPP?) to A?; (ii) reduces Sirtuin T1 (SirT1) expression, resulting in markedly differing ratios of neuroprotective SirT1 to neurotoxic SirT2; (iii) triggers Tau phosphorylation and APP phosphorylation; and (iv) induces programmed cell death. We describe a subset of drug candidates that interferes with the APP-ApoE interaction and returns the parameters noted above to normal. Our data support the hypothesis that neuronal connectivity, as reflected in the ratios of critical mediators such as sAPP?:A?, SirT1:SirT2, APP:phosphorylated (p)-APP, and Tau:p-Tau, is programmatically altered by ApoE4 and offer a simple system for the identification of program mediators and therapeutic candidates. PMID:24145446

Theendakara, Veena; Patent, Alexander; Peters Libeu, Clare A; Philpot, Brittany; Flores, Sonia; Descamps, Olivier; Poksay, Karen S; Zhang, Qiang; Cailing, Gabriellee; Hart, Matthew; John, Varghese; Rao, Rammohan V; Bredesen, Dale E

2013-11-01

419

Facultative sex ratio adjustment in response to male tarsus length in the Varied Tit Parus varius  

Microsoft Academic Search

During the last decade, evidence from a number of studies has suggested systematic devi- ations from a 1 : 1 primary sex ratio in birds, in spite of the fact that birds have chromosomal sex determination systems; the mechanism of sex allocation is not fully understood. How- ever, it still remains uncertain whether adaptive manipulations of primary sex ratio occur,

Noriyuki Yamaguchi; Katsura K. Kawano; Kazuhiro Eguchi; Tetsukazu Yahara

2004-01-01

420

An analysis of beauty as it is related to the ratio  

E-print Network

/algorithms are the Golden ratio and the Fibonacci numbers; both of which are related to each other. The Fibonacci numbers are shockingly similar to the Fibonacci numbers. Therefore, many scientists have accepted these two systems of the Fibonacci numbers almost exactly. (Hence the seashell follows the Golden Ratio, since the two

Gray, Jeffrey J.

421

Gametocyte sex ratio in single-clone infections of the malaria parasite Plasmodium mexicanum  

E-print Network

Gametocyte sex ratio in single-clone infections of the malaria parasite Plasmodium mexicanum A 12 July 2010) SUMMARY Sex ratio theory predicts that malaria parasites should bias gametocyte system later in the infection. Recent experimental studies reveal genetic variation for gametocyte sex

Schall, Joseph J.

422

Very Low Fruit:Flower Ratios in Grevillea (Proteaceae) are Independent  

E-print Network

Very Low Fruit:Flower Ratios in Grevillea (Proteaceae) are Independent of Breeding System Luise of the family Proteaceae have extremely low mature fruit : flower (FR : FL) ratios (range 0.001­0.163) compared that compatibility was an important factor explaining levels of fruit set. The role of compatibility in regulating FR

Innes, David J.

423

Uses of chloride\\/bromide ratios in studies of potable water  

Microsoft Academic Search

In natural ground water systems, both chlorine and bromine occur primarily as monovalent anions, chloride and bromide. Although dissolution or precipitation of halite, biological activity in the root zone, anion sorption, and exchange can affect chloride\\/bromide ratios in some settings, movement of the ions in potable ground water is most often conservative. Atmospheric precipitation will generally have mass ratios between

Stanley N. Davis; Donald O. Whittemore; June Fabryka-Martin

1998-01-01

424

Scanning Electron Microscope Image Signal-to-Noise Ratio Monitoring for Micro-Nanomanipulation  

E-print Network

Scanning Electron Microscope Image Signal-to-Noise Ratio Monitoring for Micro ROBOTEX (ANR-10-EQPX-44-01) projects. Key words: Scanning electron microscope, signal-to-noise ratio system, scanning electron microscope (SEM) performs an important role in autonomous micro

Paris-Sud XI, Université de

425

Rotor induced-inflow-ratio measurements and CAMRAD calculations  

NASA Technical Reports Server (NTRS)

Comparison of the inflow calculations between an analytical rotor wake method and rotor inflow measurements using a laser velocimeter was presented. The inflow measurements were made near a 4-bladed rotor system using rectangular planform blades operating in forward flight at a thrust coefficient of 0.0064, and at 3 rotor advance ratios: 0.15, 0.23, and 0.30. The inflow measurements were made at azimuthal increments of 30 degrees at 3.0 inches (approximately 1 chord) above the plane formed by the tips of the blades, and radial locations from 20 to 110 percent of blade span. The experimental measurements showed that as the advance ratio (m) increased, the induced upflow region moved progressively from the forward 20 percent of the rotor disc at m = 0.15 to covering most of the forward half of the rotor disc at m = 0.30. The induced inflow characteristics at all advance ratios were found to be unsymmetrical about the longitudinal centerline. The maximum downwash was found to be in the rear portion of the disc and skewed toward the advancing blade side. The comparisons with the analytical method Comprehensive Analytical Model of Rotorcraft Aerodynamics and Dynamics (CAMRAD) show that the region of induced upflow over the rotor disc was effectively modeled only at the advance ratio of 0.15. The method consistently indicated the largest values of induced inflow ratio to be on the retreating-blade side of the rotor disc (opposite from that measured). The importance of the choice of rotor trim option is examined and results of two trim selections are detailed.

Hoad, Danny R.

1990-01-01

426

Designing chitosan-dextran sulfate nanoparticles using charge ratios.  

PubMed

The purpose of this study was to examine the effect of charge ratio on the formation and properties of the chitosan (CS)-dextran sulfate (DS) nanoparticles developed for the delivery of water-soluble small and large molecules, including proteins. Rhodamine 6G (R6G) and bovine serum albumin (BSA) were chosen as model molecules. CS-DS nanoparticles were formulated by a complex coacervation process under mild conditions. The influence of formulation and process variables, including the charge ratio of the 2 ionic polymers, on particle size, zeta potential, and nanoparticle entrapment of R6G and BSA was studied. The in vitro release of R6G and BSA was also evaluated, and the integrity of BSA in the release fraction was assessed using sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Depending on the concentration and charge ratio of DS and CS, nanoparticles with varied size (>or=244 nm) and zeta potential (-47.1-60 mV) were obtained. High entrapment efficiency (98%) was achieved for both R6G and BSA when the charge ratio of the 2 ionic polymers was greater than 1.12. The release of both R6G and BSA from nanoparticles was based on the ion-exchange mechanism. BSA showed much slower continuous release for up to 7 days while still maintaining its integrity for an extended period. The CS-DS nanoparticles developed based on the modulation of charge ratio show promise as a system for controlled delivery of both small and large molecules, including proteins. PMID:18181558

Chen, Yan; Mohanraj, Vellore J; Wang, Fang; Benson, Heather A E

2007-01-01

427

Shear viscosity to entropy density ratio in nuclear multifragmentation  

E-print Network

Nuclear multifragmentation in intermediate energy heavy ion collisions has long been associated with liquid-gas phase transition. We calculate the shear viscosity to entropy density ratio eta/s for an equilibrated system of nucleons and fragments produced in multifragmentation within an extended statistical multifragmentation model. The temperature dependence of eta/s exhibits surprisingly similar behavior as that for water. In the coexistence phase of fragments and light particles, the ratio eta/s reaches a minimum of comparable depth as that for water in the vicinity of the critical temperature for liquid-gas phase transition. The effects of freeze-out volume and surface symmetry energy on eta/s in multifragmentation are studied.

Subrata Pal

2010-05-03

428

Liquid Crystals of Disks of Controlled Aspect Ratios  

NASA Astrophysics Data System (ADS)

Nanoparticles with quasi two-dimensional shapes serve as building blocks for discotic colloidal liquid crystals. However, due to difficulty of synthesis and especially shape-tuning of disk-shaped nanoparticles, good model systems for the study of discotic colloidal liquid crystals are hard to found. ?-zirconium phosphate (ZrP) crystals synthesized through hydrothermal treatment has regular disk shapes and controllable size, thickness, as well as size polydispersity. We experimentally illustrate that aqueous suspensions of these ZrP disks form stable liquid crystal phase easily. By choosing the thickness of the disks, an iridescent liquid crystal phase has been achieved. The critical concentration of the phase transition was found to be dependent on aspect ratios. We will also discuss our recent results on the phase diagram of discotic liquid crystals as a function of aspect ratio and particle concentration using ZrP monolayers and wax disks.

Cheng, Zhengdong; Shuai, Min; Mejia, Andres F.

2013-03-01

429

Sex-ratio meiotic drive and interspecific competition.  

PubMed

It has long been known that processes occurring within a species may impact the interactions between species. For example, as competitive ability is sensitive to parameters including reproductive rate, carrying capacity and competition efficiency, the outcome of interspecific competition may be influenced by any process that alters these attributes. Although several such scenarios have been discussed, the influence of selfish genetic elements within one species on competition between species has not received theoretical treatment. We show that, with strong competition, sex-ratio meiotic drive systems can result in a significant shift in community composition because the effective birth rate in the population may be increased by a female-biased sex ratio. Using empirical data, we attempt to estimate the magnitude of this effect in several Drosophila species. We infer that meiotic drive elements, selfish genetic elements within species, can provide a substantial competitive advantage to that species within a community. PMID:24835887

Unckless, R L; Clark, A G

2014-08-01

430

SIZE RATIOS The analysis of size ratios of coexisting species has been a major focus in  

E-print Network

for character displace- ment comes from studies of birds (Diamond et al. 1989),lizards (Losos 1990), fish) suggested that body size differ- ences among predators should evolve to reduce the effects of competition ratios of several pairs of sympatric bird and mammal species ranged from 1.1 to 1.4. The mean ratio

Gotelli, Nicholas J.

431

Resonant recoil in extreme mass ratio binary black hole mergers  

SciTech Connect

The inspiral and merger of a binary black hole system generally leads to an asymmetric distribution of emitted radiation, and hence a recoil of the remnant black hole directed opposite to the net linear momentum radiated. The recoil velocity is generally largest for comparable mass black holes and particular spin configurations, and approaches zero in the extreme mass ratio limit. It is generally believed that for extreme mass ratios {eta}<<1, the scaling of the recoil velocity is |V|{proportional_to}{eta}{sup 2}, where the proportionality coefficient depends on the spin of the larger hole and the geometry of the system (e.g. orbital inclination). The small recoil velocity is due to cancellations; while the fraction of the total binary mass radiated away in gravitational waves is O({eta}), most of this energy is emitted during the inspiral phase where the momentum radiated integrates to zero over an orbit. Here, we show that for low but nonzero inclination prograde orbits and very rapidly spinning large holes (spin parameter a{sub *}>0.9678) the inspiralling binary can pass through resonances where the orbit-averaged radiation-reaction force is nonzero. These resonance crossings lead to a new contribution to the kick, |V|{proportional_to}{eta}{sup 3/2}. For these configurations and sufficiently extreme mass ratios, this resonant recoil is dominant. While it seems doubtful that the resonant recoil will be astrophysically significant, its existence suggests caution when extrapolating the results of numerical kick results to extreme mass ratios and near-maximal spins.

Hirata, Christopher M. [Caltech M/C 350-17, Pasadena, California 91125 (United States)

2011-05-15

432

CFD assessment of orifice aspect ratio and mass flow ratio on jet mixing in rectangular ducts  

NASA Technical Reports Server (NTRS)

Isothermal CFD analysis was performed on axially opposed rows of jets mixing with cross flow in a rectangular duct. Laterally, the jets' centerlines were aligned with each other on the top and bottom walls. The focus of this study was to characterize the effects of orifice aspect ratio and jet-to-mainstream mass flow ratio on jet penetration and mixing. Orifice aspect ratios (L/W) of 4-to-1, 2-to-1, and 1-to-1, along with circular holes, were parametrically analyzed. Likewise, jet-to-mainstream mass flow ratios (MR) of 2.0, 0.5, and 0.25 were systematically investigated. The jet-to-mainstream momentum-flux ratio (J) was maintained at 36 for all cases, and the orifice spacing-to-duct height (S/H) was varied until optimum mixing was attained for each configuration. The numerical results showed that orifice aspect ratio (and likewise orifice blockage) had little effect on jet penetration and mixing. Based on mixing characteristics alone, the 4-to-1 slot was comparable to the circular orifice. The 4-to-1 slot has a smaller jet wake which may be advantageous for reducing emissions. However, the axial length of a 4-to-1 slot may be prohibitively long for practical application, especially for MR of 2.0. The jet-to-mainstream mass flow ratio had a more significant effect on jet penetration and mixing. For a 4-to-1 aspect ratio orifice, the design correlating parameter for optimum mixing (C = (S/H)(sq. root J)) varied from 2.25 for a mass flow ratio of 2.0 to 1.5 for a mass flow ratio of 0.25.

Bain, D. B.; Smith, C. E.; Holdeman, J. D.

1994-01-01

433

CHARACTERIZING TRITIUM WASTE USING HELIUM RATIOS  

SciTech Connect

When routine sampling revealed greatly elevated tritium levels (3.14 x 105 Bq/L [8.5-million pCi/liter]) in the groundwater near a solid waste landfill at the Hanford Site, an innovative technique was used to assess the extent of the plume. Helium-3/helium-4 ratios, relative to ambient air-in-soil gas samples, were used to identify the tritium source and initially delineate the extent of the groundwater tritium plume. This approach is a modification of a technique developed in the late 1960s to age-date deep ocean water as part of the GEOSECS ocean monitoring program. Poreda, et al. (1) and Schlosser, et al. (2) applied this modified technique to shallow aquifers. A study was also conducted to demonstrate the concept of using helium-3 as a tool to locate vadose zone sources of tritium and tracking groundwater tritium plumes at Hanford (3). Seventy sampling points were installed around the perimeter and along four transects downgradient of the burial ground. Soil gas samples were collected, analyzed for helium isotopes, and helium-3/helium-4 ratios were calculated for these 70 points. The helium ratios indicated a vadose zone source of tritium along the northern edge of the burial ground that is likely the source of tritium in the groundwater. The helium ratios also indicate the groundwater plume is traveling east-northeast from the burial ground and that no up-gradient tritium sources are affecting the burial ground. Based on the helium ratio results, six downgradient groundwater sampling locations were identified to verify the tritium plume extent and groundwater tritium concentrations. The tritium results from the initial groundwater samples confirmed that elevated helium ratios were indicative of tritium contamination in the local groundwater. The measurement of helium isotopes in soil gas provided a rapid and cost- effective technique to define the shape and extent of tritium contamination from the burial ground. Using this soil gas sampling approach, the project team was able to identify areas where elevated tritium existed in groundwater without going to the time and expense of conducting conventional groundwater characterization sampling. The savings from this characterization approach were $1.4 million.

Ovink, R.W.; McMahon, W.J.; Borghese, J.V.; Olsen, K.B.

2003-02-27

434

Isotope ratio monitoring gas chromatography/Mass spectrometry of D/H by high temperature conversion isotope ratio mass spectrometry.  

PubMed

Of all the elements, hydrogen has the largest naturally occurring variations in the ratio of its stable isotopes (D/H). It is for this reason that there has been a strong desire to add hydrogen to the list of elements amenable to isotope ratio monitoring gas chromatography/mass spectrometry (irm-GC/MS). In irm-GC/MS the sample is entrained in helium as the carrier gas, which is also ionized and separated in the isotope ratio mass spectrometer (IRMS). Because of the low abundance of deuterium in nature, precise and accurate on-line monitoring of D/H ratios with an IRMS requires that low energy helium ions be kept out of the m/z 3 collector, which requires the use of an energy filter. A clean mass 3 (HD(+.)) signal which is independent of a large helium load in the electron impact ion source is essential in order to reach the sensitivity required for D/H analysis of capillary GC peaks. A new IRMS system, the DELTA(plus)XL(trade mark), has been designed for high precision, high accuracy measurements of transient signals of hydrogen gas. It incorporates a retardation lens integrated into the m/z 3 Faraday cup collector. Following GC separation, the hydrogen bound in organic compounds must be quantitatively converted into H(2) gas prior to analysis in the IRMS. Quantitative conversion is achieved by high temperature conversion (TC) at temperatures >1400 degrees C. Measurements of D/H ratios of individual organic compounds in complicated natural mixtures can now be made to a precision of 2 per thousand (delta notation) or, better, with typical sample amounts of approximately 200 ng per compound. Initial applications have focused on compounds of interest to petroleum research (biomarkers and natural gas components), food and flavor control (vanillin and ethanol), and metabolic studies (fatty acids and steroids). Copyright 1999 John Wiley & Sons, Ltd. PMID:10407302

Hilkert; Douthitt; Schlüter; Brand

1999-07-01

435

Guidelines and recommended terms for expression of stable-isotope-ratio and gas-ratio measurement results  

USGS Publications Warehouse

To minimize confusion in the expression of measurement results of stable isotope and gas-ratio measurements, recommendations based on publications of the Commission on Isotopic Abundances and Atomic Weights of the International Union of Pure and Applied Chemistry (IUPAC) are presented. Whenever feasible, entries are consistent with the Système International d'Unités, the SI (known in English as the International System of Units), and the third edition of the International Vocabulary of Basic and General Terms in Metrology (VIM, 3rd edition). The recommendations presented herein are approved by the Commission on Isotopic Abundances and Atomic Weights and are designed to clarify expression of quantities related to measurement of isotope and gas ratios to ensure that quantity equations instead of numerical value equations are used for quantity definitions. Examples of column headings consistent with quantity calculus (also called the algebra of quantities) and examples of various deprecated usages connected with the terms recommended are presented.

Coplen, Tyler B.

2011-01-01

436

Gyromagnetic ratio of a massive body.  

NASA Technical Reports Server (NTRS)

It is well known that the gyromagnetic ratio (g factor) of a classical, slowly rotating body whose charge density is proportional to its mass density must be equal to unity. However, if the body is very massive, the spacetime curvature effects of general relativity become important and the result g = 1 is no longer valid. We calculate here the gyromagnetic ratio of a slowly rotating, massive shell with uniform charge density. When the shell is large compared with the Schwarzschild radius we have g = 1, but as the shell becomes more massive the g factor increases. In the limit as the shell approaches its Schwarzschild radius we obtain g approaching 2 (the same value as for an electron).

Cohen, J. M.; Tiomno, J.; Wald, R. M.

1973-01-01

437

Sodium\\/Potassium Ratio in Rainwater  

Microsoft Academic Search

DR. B. C. V. ODDIE has commented1 on a portion of my recent article ``Surface of the Ocean as a Source of Air-Borne Nitrogenous Material and Other Plant Nutrients''