Science.gov

Sample records for hermetic reciprocating compressors

  1. An Investigation on the Pin Bearings’ Optimization of a Hermetic Reciprocating Compressor

    NASA Astrophysics Data System (ADS)

    Ozdemir, A. R.; Hacioglu, B.; Kasapoglu, E.

    2015-08-01

    A hermetic reciprocating compressor is the most energy consuming component of the refrigerators. Therefore performance improvement studies of the compressor play an important role to reduce overall energy consumption of the refrigerators. Design of bearings is one of the major study areas influencing reciprocating compressor performance. In this study crank pin and piston pin bearings in hermetic compressor applications are investigated and optimized. The effect of operating conditions, bearing offset between crank pin and piston pin, bearing clearance and bearing location along the shaft on the friction loss were investigated and optimal bearing designs were developed. Efficiency measurements of the compressor showed that the improved crank pin and piston pin bearing designs provide up to 3.8% increase in the COP as a result of reduction in mechanical loss that is significantly influenced by the length of the bearings, bearing location along the shaft and operating conditions.

  2. A novel Sigma Delta ADC application oriented to test hermetic reciprocating compressors

    NASA Astrophysics Data System (ADS)

    Raush, G.; Rigola, J.; Pérez-Segarra, D.; Oliva, A.

    2004-11-01

    A novel data acquisition approach to test hermetic reciprocating compressors is presented. A non-uniformly sampled application of a SgrDgr analogue-to-digital converter was used to investigate the compressor pV diagram, together with accurate spectral analysis of pressure readings. Several previous approaches are presented and compared with the one proposed here. Different statistical comparisons have been carried out with the main objective of demonstrating the good performance of the proposal.

  3. A thermal model for analysis of hermetic reciprocating compressors under the on-off cycling operating condition

    NASA Astrophysics Data System (ADS)

    Lohn, S. K.; Diniz, M. C.; Deschamps, C. J.

    2015-08-01

    The on-off cycling operating condition of compressors is very common in low capacity refrigeration systems, being characterized by alternate periods in which the compressor is either operating (on) or idle (off). Thermal interactions between the compressor components affect its performance during the operating period and establish the initial condition for the compressor start up from idle condition. This paper presents a numerical model to predict the temperature field of hermetic reciprocating compressors under on-off cycling conditions. The model adopts a lumped formulation for control volumes formed in the fluid solution domain and the finite volume method to solve heat conduction in the solid components. Some required heat transfer coefficients were experimentally adjusted. Predictions for temperature were compared to measurements and good agreement was observed, especially for the thermal transient during the period in which the compressor is off.

  4. A thermal network model for induction motors of hermetic reciprocating compressors

    NASA Astrophysics Data System (ADS)

    Dutra, T.; Deschamps, C. J.

    2015-08-01

    This paper describes a simulation model for small reciprocating compressors with emphasis on the electrical motor modelling. Heat transfer is solved through algebraic equations derived from lumped thermal energy balances applied to the compressor components. Thermal conductances between the motor components are characterized via a thermal network model. The single-phase induction motor is modelled via an equivalent circuit, allowing predictions for the motor performance and distributed losses. The predicted temperature distribution is used to evaluate the stator and rotor windings resistances. The thermal and electric models are solved in a coupled manner with a model for the compression cycle. Predictions of temperature distribution, motor efficiency, as well as isentropic and volumetric efficiencies, are compared with experimental data at different operating conditions. The model is then applied to analyse the motor temperature as a function of input voltage and stator wire diameter.

  5. Oil cooled, hermetic refrigerant compressor

    DOEpatents

    English, W.A.; Young, R.R.

    1985-05-14

    A hermetic refrigerant compressor having an electric motor and compressor assembly in a hermetic shell is cooled by oil which is first cooled in an external cooler and is then delivered through the shell to the top of the motor rotor where most of it is flung radially outwardly within the confined space provided by the cap which channels the flow of most of the oil around the top of the stator and then out to a multiplicity of holes to flow down to the sump and provide further cooling of the motor and compressor. Part of the oil descends internally of the motor to the annular chamber to provide oil cooling of the lower part of the motor, with this oil exiting through vent hole also to the sump. Suction gas with entrained oil and liquid refrigerant therein is delivered to an oil separator from which the suction gas passes by a confined path in pipe to the suction plenum and the separated oil drops from the separator to the sump. By providing the oil cooling of the parts, the suction gas is not used for cooling purposes and accordingly increase in superheat is substantially avoided in the passage of the suction gas through the shell to the suction plenum. 3 figs.

  6. Oil cooled, hermetic refrigerant compressor

    DOEpatents

    English, William A.; Young, Robert R.

    1985-01-01

    A hermetic refrigerant compressor having an electric motor and compressor assembly in a hermetic shell is cooled by oil which is first cooled in an external cooler 18 and is then delivered through the shell to the top of the motor rotor 24 where most of it is flung radially outwardly within the confined space provided by the cap 50 which channels the flow of most of the oil around the top of the stator 26 and then out to a multiplicity of holes 52 to flow down to the sump and provide further cooling of the motor and compressor. Part of the oil descends internally of the motor to the annular chamber 58 to provide oil cooling of the lower part of the motor, with this oil exiting through vent hole 62 also to the sump. Suction gas with entrained oil and liquid refrigerant therein is delivered to an oil separator 68 from which the suction gas passes by a confined path in pipe 66 to the suction plenum 64 and the separated oil drops from the separator to the sump. By providing the oil cooling of the parts, the suction gas is not used for cooling purposes and accordingly increase in superheat is substantially avoided in the passage of the suction gas through the shell to the suction plenum 64.

  7. Dual capacity reciprocating compressor

    DOEpatents

    Wolfe, R.W.

    1984-10-30

    A multi-cylinder compressor particularly useful in connection with northern climate heat pumps and in which different capacities are available in accordance with reversing motor rotation is provided with an eccentric cam on a crank pin under a fraction of the connecting rods, and arranged for rotation upon the crank pin between opposite positions 180[degree] apart so that with cam rotation on the crank pin such that the crank throw is at its normal maximum value all pistons pump at full capacity, and with rotation of the crank shaft in the opposite direction the cam moves to a circumferential position on the crank pin such that the overall crank throw is zero. Pistons whose connecting rods ride on a crank pin without a cam pump their normal rate with either crank rotational direction. Thus a small clearance volume is provided for any piston that moves when in either capacity mode of operation. 6 figs.

  8. Dual capacity reciprocating compressor

    DOEpatents

    Wolfe, Robert W.

    1984-01-01

    A multi-cylinder compressor 10 particularly useful in connection with northern climate heat pumps and in which different capacities are available in accordance with reversing motor 16 rotation is provided with an eccentric cam 38 on a crank pin 34 under a fraction of the connecting rods, and arranged for rotation upon the crank pin between opposite positions 180.degree. apart so that with cam rotation on the crank pin such that the crank throw is at its normal maximum value all pistons pump at full capacity, and with rotation of the crank shaft in the opposite direction the cam moves to a circumferential position on the crank pin such that the overall crank throw is zero. Pistons 24 whose connecting rods 30 ride on a crank pin 36 without a cam pump their normal rate with either crank rotational direction. Thus a small clearance volume is provided for any piston that moves when in either capacity mode of operation.

  9. Hermetic compressor and block expansion valve in refrigeration performance

    NASA Astrophysics Data System (ADS)

    Santoso, Budi; Susilo, Didik Djoko; Tjahjana, D. D. D. P.

    2016-03-01

    Vehicle cabin in tropical countries requires the cooling during the day for comfort of passengers. Air conditioning machine is commonly driven by an internal combustion engine having a great power, which the conventional compressor is connected to crank shaft. The stage of research done is driving the hermetic compressor with an electric motor, and using block expansion valve. The HFC-134a was used as refrigerant working. The primary parameters observed during the experiment are pressure, temperature, and power consumption for different cooling capacities. The results show that the highest coefficient of performance (COP) and the electric power of system are 6.3 and 638 Watt, respectively.

  10. Performance enhancement of hermetic compressor using phase change materials

    NASA Astrophysics Data System (ADS)

    Mahmoud, I. M.; Rady, M. A.; Huzayyin, A. S.

    2015-08-01

    The present study is motivated by the need for the research of simple measures for increasing energy efficiency of hermetic compressor. The measure is the application of phase change materials for performance enhancement. The first experimental study should be guide for choice of PCM. It has been performed to investigate the effects of thermostat setting temperature on the performance of hermetic compressor. The effects of thermostat setting temperature with and without load on power consumption have been analyzed. Performance enhancement using phase change materials (PCMs) has been studied by employing a phase change material Rubitherm-42 (RT-42) on the top surface of compressor. Choice of PCM material is based on basic compressor performance measured in the first part of the present study. Experiments have been carried out for different load values and different quantities of PCM. The quantity and phase change characteristic of PCM are essential parameters that determine the percentage of performance enhancement in term of energy consumption. Reduction of energy consumption of about 10% has been achieved in the present study by using PCM. The present study shows that how to reduce the electrical power consumption to enhance compressor heat dissipation method to improve efficiency.

  11. 30 CFR 57.13010 - Reciprocating-type air compressors.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Reciprocating-type air compressors. 57.13010... Air and Boilers § 57.13010 Reciprocating-type air compressors. (a) Reciprocating-type air compressors... than 25 percent. (b) However, this standard does not apply to reciprocating-type air compressors...

  12. 30 CFR 57.13010 - Reciprocating-type air compressors.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Reciprocating-type air compressors. 57.13010... Air and Boilers § 57.13010 Reciprocating-type air compressors. (a) Reciprocating-type air compressors... than 25 percent. (b) However, this standard does not apply to reciprocating-type air compressors...

  13. 30 CFR 57.13010 - Reciprocating-type air compressors.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Reciprocating-type air compressors. 57.13010... Air and Boilers § 57.13010 Reciprocating-type air compressors. (a) Reciprocating-type air compressors... than 25 percent. (b) However, this standard does not apply to reciprocating-type air compressors...

  14. 30 CFR 56.13010 - Reciprocating-type air compressors.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Reciprocating-type air compressors. 56.13010... and Boilers § 56.13010 Reciprocating-type air compressors. (a) Reciprocating-type air compressors... than 25 percent. (b) However, this standard does not apply to reciprocating-type air compressors...

  15. 30 CFR 57.13010 - Reciprocating-type air compressors.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Reciprocating-type air compressors. 57.13010... Air and Boilers § 57.13010 Reciprocating-type air compressors. (a) Reciprocating-type air compressors... than 25 percent. (b) However, this standard does not apply to reciprocating-type air compressors...

  16. 30 CFR 56.13010 - Reciprocating-type air compressors.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Reciprocating-type air compressors. 56.13010... and Boilers § 56.13010 Reciprocating-type air compressors. (a) Reciprocating-type air compressors... than 25 percent. (b) However, this standard does not apply to reciprocating-type air compressors...

  17. Analysis of reciprocating compressor piston rod failures

    SciTech Connect

    Tripp, H.A.; Drosjack, M.J.

    1984-02-01

    This report presents the analysis of five piston rod failures which occurred on reciprocating compressors. Calculations are shown for rod stress which includes nominal rod loading sources as well as additional loads due to unusual pressure losses in the compressor valves, flexure of the rods due to misalignment, and manufacturing errors. The additional loads were incorporated on the basis of field measurements. The stress values are used with Baquin's equation to produce fatigue life curves for the rods. Based on the calculations, recommendations for modified rods were made. The calculation procedures are described in a manner which will permit their application to other reciprocating compressors.

  18. An Analysis of Reciprocating Compressor Suction System Using Digital Image Processing

    NASA Astrophysics Data System (ADS)

    Lee, In-Seop; Kaga, Akikazu; Yamaguchi, Katsuhito

    In a reciprocating compressor having close distance between a suction pipe and a suction muffler, great part of refrigerant flowing from the suction pipe is directly sucked into the suction muffler. But a part of refrigerant leaks into the void space in the hermetic shell and contacts with the cylinder, the motor or other high temperature parts. The temperature rise of refrigerant due to this leakage decreases the efficiency of a compressor. Therefore the efficiency of the compressor increases with decrease the amount of leakage. In this paper, the direct suction ratio (DSR) is defined as the ratio of the flow rate of refrigerant directly sucked to the total flow rate from the suction pipe, and measured with a new technique using digital image processing. The technique developed measures the temporal decrease of visible tracer particles filled initially within the hermetic shell of a compressor visualization model, and calculates the DSR from the rate of concentration decrease. The technique is applied to improve the performance of reciprocating compressor by modifying the shape of the suction pipe which gives higher DSR. Although refrigerant flow velocity around suction pipe and muffler is required as a fundamental data for further improvement of the performance, there has been no report or paper which measures these data due to the difficulty in insertion of velocity sensor into hermetic shell. In this paper, flow velocity data obtained with a PIV (Particle Imaging Velocimetry) technique applied to compressor visualization model is also presented.

  19. 30 CFR 56.13010 - Reciprocating-type air compressors.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Reciprocating-type air compressors. 56.13010... NONMETAL MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-SURFACE METAL AND NONMETAL MINES Compressed Air and Boilers § 56.13010 Reciprocating-type air compressors. (a) Reciprocating-type air...

  20. 30 CFR 56.13010 - Reciprocating-type air compressors.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Reciprocating-type air compressors. 56.13010... NONMETAL MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-SURFACE METAL AND NONMETAL MINES Compressed Air and Boilers § 56.13010 Reciprocating-type air compressors. (a) Reciprocating-type air...

  1. 30 CFR 56.13010 - Reciprocating-type air compressors.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Reciprocating-type air compressors. 56.13010... NONMETAL MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-SURFACE METAL AND NONMETAL MINES Compressed Air and Boilers § 56.13010 Reciprocating-type air compressors. (a) Reciprocating-type air...

  2. 19. View northwest of Tropic Chamber reciprocal compressors (typical), in ...

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

    19. View northwest of Tropic Chamber reciprocal compressors (typical), in machine area. - Natick Research & Development Laboratories, Climatic Chambers Building, U.S. Army Natick Research, Development & Engineering Center (NRDEC), Natick, Middlesex County, MA

  3. Development of a stochastic dynamical model for hermetic compressor's components with experimental investigation

    NASA Astrophysics Data System (ADS)

    Fontanela, F.; Silva, O. M.; Lenzi, A.; Ritto, T. G.

    2016-08-01

    The analysis of household compressor's components is typically evaluated by using mathematical-mechanical models, and many decisions are taken based on simulations. However, such an investigation is usually performed in a deterministic framework, which cannot consider manufacturing variabilities and epistemic uncertainties. In this paper, a stochastic structural model that considers data and model uncertainties is developed for a discharge pipe connected to a hermetic compressor's shell. An experimental test rig is constructed to test each part separately, and an identification strategy is proposed to fit the stochastic model to experimental results. Finally, the impact of the uncertainties in each structural component on the dynamical responses of the whole system is investigated. It turns out that: (1) the proposed stochastic dynamical model presented very good results when compared to the experimental responses, and (2) uncertainties in the discharge pipe model play an important role in the coupled system dynamics.

  4. Fault detection in reciprocating compressor valves under varying load conditions

    NASA Astrophysics Data System (ADS)

    Pichler, Kurt; Lughofer, Edwin; Pichler, Markus; Buchegger, Thomas; Klement, Erich Peter; Huschenbett, Matthias

    2016-03-01

    This paper presents a novel approach for detecting cracked or broken reciprocating compressor valves under varying load conditions. The main idea is that the time frequency representation of vibration measurement data will show typical patterns depending on the fault state. The problem is to detect these patterns reliably. For the detection task, we make a detour via the two dimensional autocorrelation. The autocorrelation emphasizes the patterns and reduces noise effects. This makes it easier to define appropriate features. After feature extraction, classification is done using logistic regression and support vector machines. The method's performance is validated by analyzing real world measurement data. The results will show a very high detection accuracy while keeping the false alarm rates at a very low level for different compressor loads, thus achieving a load-independent method. The proposed approach is, to our best knowledge, the first automated method for reciprocating compressor valve fault detection that can handle varying load conditions.

  5. Dynamic study of piping systems for reciprocating compressors

    SciTech Connect

    Wakabayashi, A.; Arai, S.; Yamada, S.

    1995-12-01

    Recently the authors have developed the direct method to study vibration of piping systems for reciprocating compressors, based on the requirement by API-618 Design Approach-3. They have examined the reliability of this direct method by some experiments with a test piping system, by pressure pulsation and nodal vibration measurements. Overall pressure pulsation amplitude and its frequency components at each measurement point were proved.to agree with the results by digital analysis. Close evaluation of ``pipe-supports` stiffness``, as well as boundary conditions, was confirmed to be a necessary condition to proceed the dynamic analysis of the piping system in relation to the pressure pulsation Generated by the reciprocating compressor, which affected the accuracy of final estimation of nodal displacement distribution of the piping system. Field data evaluation is also discussed in this paper.

  6. Breaking-in Mechanism of the Sliding Surface in a Hermetic Rotary Compressor Employed an Ion-nitrided Crankshaft

    NASA Astrophysics Data System (ADS)

    Sato, Shinobu; Machida, Tadao; Komine, Kenji

    In view of a wide range of its speed and a long operation period,attempts have been made to develop high reliability of an inverter controlled compressor designed for a residential heat pump unit. A significant improvement in the long term reliability has been demonstrated by employing a ion-nitrided crankshaft which would help minimizing wear of the bearing. This paper presents the dependency of breaking-in phenomena in hermetic rotary compressors on material combination and discusses the relationship between chemical reaction and wear progressiveness of sliding surface.

  7. Fluid Flow in the Oil Pumping System of a Hermetic Compressor

    NASA Astrophysics Data System (ADS)

    Posch, S.; Berger, E.; Heimel, M.; Hopfgartner, J.; Almbauer, R.; Schöllauf, P.

    2015-08-01

    This work deals with the investigation of the oil pumping system in hermetic compressors for refrigeration application. The oil pump which is used for this study consists of two pumping areas: the lower pumping area with a pick-up tube and an eccentric bore, and the upper pumping area with a helical groove. This study focuses on the helical groove in the upper pumping area. To analyse the fluid flow in the helical groove, a numerical approach is introduced. In this approach the Navier-Stokes equations are adapted to the problem and are solved by using the finite volume method. Compared to analytical models, this method is able to obtain the flow field in the cross section of the helical groove at higher resolution. The higher geometrical resolution also enables the analysis of the flow in the small gap between the rotating crankshaft and the stationary wall. The present method is used to quantify different operating parameters on the oil mass flow rate.

  8. Reciprocating and Screw Compressor semi-empirical models for establishing minimum energy performance standards

    NASA Astrophysics Data System (ADS)

    Javed, Hassan; Armstrong, Peter

    2015-08-01

    The efficiency bar for a Minimum Equipment Performance Standard (MEPS) generally aims to minimize energy consumption and life cycle cost of a given chiller type and size category serving a typical load profile. Compressor type has a significant chiller performance impact. Performance of screw and reciprocating compressors is expressed in terms of pressure ratio and speed for a given refrigerant and suction density. Isentropic efficiency for a screw compressor is strongly affected by under- and over-compression (UOC) processes. The theoretical simple physical UOC model involves a compressor-specific (but sometimes unknown) volume index parameter and the real gas properties of the refrigerant used. Isentropic efficiency is estimated by the UOC model and a bi-cubic, used to account for flow, friction and electrical losses. The unknown volume index, a smoothing parameter (to flatten the UOC model peak) and bi-cubic coefficients are identified by curve fitting to minimize an appropriate residual norm. Chiller performance maps are produced for each compressor type by selecting optimized sub-cooling and condenser fan speed options in a generic component-based chiller model. SEER is the sum of hourly load (from a typical building in the climate of interest) and specific power for the same hourly conditions. An empirical UAE cooling load model, scalable to any equipment capacity, is used to establish proposed UAE MEPS. Annual electricity use and cost, determined from SEER and annual cooling load, and chiller component cost data are used to find optimal chiller designs and perform life-cycle cost comparison between screw and reciprocating compressor-based chillers. This process may be applied to any climate/load model in order to establish optimized MEPS for any country and/or region.

  9. A Diagnosis method of the small end fault on reciprocating compressor connecting rod

    NASA Astrophysics Data System (ADS)

    Jiang, Zhinong; Mao, Zhiwei; Yao, Ziyun; Zhang, Jinjie

    2015-08-01

    The connecting rod is the key moving part of a reciprocating compressor, of which the stress state is extremely complicate and the wear fault of the small end is always a bottleneck problem in the field of fault monitoring and diagnosing. This paper is aimed to present a new method to diagnose the above wear fault. Firstly, a contact model of a clearance in the revolute joint of the small end of a connecting rod bearing (SECRB) was established and a multi-body simulation tool was utilized to simulate the slider-crank mechanism with a clearance, from which the dynamic influence of wear gap in SECRB of a slider-crank mechanism was obtained. Based on the study above, we extracted the characteristics of the wear fault of SECRB and then proposed a brand new approach to monitoring and diagnosing this wear fault by analyzing the angle domain of vibration signals. The availability was verified by conducting an experiment on a reciprocating compressor. And the experimental results show that this method can not only accurately diagnose the wear fault of SECRB but also approximately estimate its severity. This study laid a foundation for the online monitoring and early warning of this fault.

  10. Performance of R-410A Alternative Refrigerants in a Reciprocating Compressor Designed for Air Conditioning Applications

    SciTech Connect

    Shrestha, Som S; Vineyard, Edward Allan; Mumpower, Kevin

    2016-01-01

    In response to environmental concerns raised by the use of refrigerants with high Global Warming Potential (GWP), the Air-Conditioning, Heating, and Refrigeration Institute (AHRI) has launched an industry-wide cooperative research program, referred to as the Low-GWP Alternative Refrigerants Evaluation Program (AREP), to identify and evaluate promising alternative refrigerants for major product categories. After successfully completing the first phase of the program in December 2013, AHRI launched a second phase of the Low-GWP AREP in 2014 to continue research in areas that were not previously addressed, including refrigerants in high ambient conditions, refrigerants in applications not tested in the first phase, and new refrigerants identified since testing for the program began. Although the Ozone Depletion Potential of R-410A is zero, this refrigerant is under scrutiny due to its high GWP. Several candidate alternative refrigerants have already demonstrated low global warming potential. Performance of these low-GWP alternative refrigerants is being evaluated for Air conditioning and heat pump applications to ensure acceptable system capacity and efficiency. This paper reports the results of a series of compressor calorimeter tests conducted for the second phase of the AREP to evaluate the performance of R-410A alternative refrigerants in a reciprocating compressor designed for air conditioning systems. It compares performance of alternative refrigerants ARM-71A, L41-1, DR-5A, D2Y-60, and R-32 to that of R-410A over a wide range of operating conditions. The tests showed that, in general, cooling capacities were slightly lower (except for the R-32), but energy efficiency ratios (EER) of the alternative refrigerants were comparable to that of R-410A.

  11. Torsional Vibration Analysis of Reciprocating Compressor Trains driven by Induction Motors

    NASA Astrophysics Data System (ADS)

    Brunelli, M.; Fusi, A.; Grasso, F.; Pasteur, F.; Ussi, A.

    2015-08-01

    The dynamic study of electric motor driven compressors, for Oil&Gas (O&G) applications, are traditionally performed in two steps separating the mechanical and the electrical systems. The packager conducts a Torsional Vibration Analysis (TVA) modeling the mechanical system with a lumped parameter scheme, without taking into account the electrical part. The electric motor supplier later performs a source current pulsation analysis on the electric motor system, based on the TVA results. The mechanical and the electrical systems are actually linked by the electromagnetic effect. The effect of the motor air-gap on TVA has only recently been taken into account by adding a spring and a damper between motor and ground in the model. This model is more accurate than the traditional one, but is applicable only to the steady-state condition and still fails to consider the reciprocal effects between the two parts of the system. In this paper the torsional natural frequencies calculated using both the traditional and the new model have been compared. Furthermore, simulation of the complete system has been achieved through the use of LMS AMESim, multi-physics, one-dimensional simulation software that simultaneously solves the shafts rotation and electric motor voltage equation. Finally, the transient phenomena that occur during start-up have been studied.

  12. P-V diagram simulation: a new approach to modeling reciprocating compressor performance

    SciTech Connect

    Bishop, L.E.

    1983-10-01

    Exxon's King Ranch Gas Plant operates twenty-seven integral engine/compressors totaling 49,000 horsepower for inlet gas compression. The plant no longer depends on theoretical volumetric efficiency, calculated throughput, and brake horsepower per million curves, for engine loading. A computer model has been developed that utilizes the pressure-volume relationship within individual compressor cylinders to predict horsepower independently of throughput. The data base for this new approach was derived from routine tests conducted with a digital engine/compressor analyzer. The study used to develop this program has provided new experience and information about the expected value of the polytropic exponent of compression, ''n''. With only this ''n'' value, clearance data, and approximate values for inlet and discharge pressure losses, individual cylinder performance can be predicted within an accuracy of two percent. This paper addresses key aspects of the new approach, and presents case history test results. The resulting compressor loading data permit operating personnel to load engines at rated capacity without concern for overload, resulting in increased fuel efficiency and greater plant throughput. A Hewlett-Packard 41-CV calculator version of the simulator is listed in the Appendix.

  13. An investigation of the orthogonal outputs from an on-rotor MEMS accelerometer for reciprocating compressor condition monitoring

    NASA Astrophysics Data System (ADS)

    Feng, G.; Hu, N.; Mones, Z.; Gu, F.; Ball, A. D.

    2016-08-01

    With rapid development in electronics and microelectromechanical systems (MEMS) technology, it becomes possible and attractive to monitor rotor dynamics by directly installing MEMS accelerometers on rotors. This paper studies the mathematical modelling of the orthogonal outputs from an on-rotor MEMS accelerometer and proposes a method to eliminate the gravitational acceleration projected on the measurement axes. This is achieved by shifting the output in the normal direction by π / 2 using a Hilbert transform and then combining it with the output of the tangential direction. With further compensation of the combined signal in the frequency domain, the tangential acceleration of the rotor is reconstructed to a high degree of accuracy. Experimental results show that the crankshaft tangential acceleration of a reciprocating compressor, obtained by the proposed method, can discriminate clearly between different discharge pressures and hence can allow common leakage faults to be detected, located and diagnosed for online condition monitoring purposes.

  14. Automation of reciprocating gas engine compressor packages using programmable logic controllers

    SciTech Connect

    Goff, W. )

    1990-09-01

    An approach taken to automate gas/engine compressor skid-mounted packages is described. The approach includes design criteria with special considerations relating to the application of programmable logic controllers (PLC's). Using typical industry standard specifications along with I/O lists, sequence narratives, and logic diagrams, the PLC's may be programmed to perform the desired operation. The added capabilities of the PLC enhance simulation, checkout, and startup.

  15. A parameters optimization method for planar joint clearance model and its application for dynamics simulation of reciprocating compressor

    NASA Astrophysics Data System (ADS)

    Hai-yang, Zhao; Min-qiang, Xu; Jin-dong, Wang; Yong-bo, Li

    2015-05-01

    In order to improve the accuracy of dynamics response simulation for mechanism with joint clearance, a parameter optimization method for planar joint clearance contact force model was presented in this paper, and the optimized parameters were applied to the dynamics response simulation for mechanism with oversized joint clearance fault. By studying the effect of increased clearance on the parameters of joint clearance contact force model, the relation of model parameters between different clearances was concluded. Then the dynamic equation of a two-stage reciprocating compressor with four joint clearances was developed using Lagrange method, and a multi-body dynamic model built in ADAMS software was used to solve this equation. To obtain a simulated dynamic response much closer to that of experimental tests, the parameters of joint clearance model, instead of using the designed values, were optimized by genetic algorithms approach. Finally, the optimized parameters were applied to simulate the dynamics response of model with oversized joint clearance fault according to the concluded parameter relation. The dynamics response of experimental test verified the effectiveness of this application.

  16. Bearing construction for refrigeration compressor

    SciTech Connect

    Middleton, M.G.; Nelson, R.T.

    1988-01-12

    A hermetic refrigeration compressor has a cylinder block and a crankshaft rotatable about a vertical axis to reciprocate a piston in a cylinder on the cylinder block. A separate bearing housing is secured to the central portion of the cylinder block and extends vertically along the crankshaft, where it carries a pair of roller bearings to journal the crankshaft. The crankshaft has a radially extending flange which is journaled by a thrust-type roller bearing above the bearing housing to absorb the vertical forces on the crankshaft so that all three of the roller bearings are between the crankshaft and the bearing housing to maintain and control the close tolerances required by such bearings. 4 figs.

  17. Compressor performance at high suction temperatures with application to solar heat pump

    SciTech Connect

    Kush, E A

    1980-01-01

    As part of the study of Solar Assisted Heat Pump (SAHP) Systems, the performance of the heat pump itself and its components under conditions attendant to series solar input to the evaporator is being investigated at Brookhaven National Laboratory (BNL). Particular emphasis has been placed on the details of the compressor performance, since in order to properly exploit the thermodynamic potential of high solar input temperatures (40 to 100/sup 0/F), the compressor must operate efficiently over a wide range of (saturated) suction temperatures most of which are well above those for which present compressors are designed. A systematic series of experiments is being conducted at evaporating temperatures in the range from 45 to 100/sup 0/F using a Solar Heat Pump Simulator and a specially designed Laboratory Model Heat Pump assembled from off-the-shelf components. Two reciprocating compressors have been tested thus far - an open type driven by a 2-speed motor and a hermetic 2-speed, the multi-speed feature providing capacity control, which is a virtual necessity for effective use of solar source. Thorough and highly accurate instrumentation is used in the simulator and in the heat pump refrigeration loop. The results to date of the compressor aspects of the solar heat pump experiments at BNL are described, and the general application of heat pumps and their compressors to use with solar input are discussed.

  18. Suction muffler for refrigeration compressor

    DOEpatents

    Nelson, Richard T.; Middleton, Marc G.

    1983-01-01

    A hermetic refrigeration compressor includes a suction muffler formed from two pieces of plastic material mounted on the cylinder housing. One piece is cylindrical in shape with an end wall having an aperture for receiving a suction tube connected to the cylinder head. The other piece fits over and covers the other end of the cylindrical piece, and includes a flaring entrance horn which extends toward the return line on the sidewall of the compressor shell.

  19. Suction muffler for refrigeration compressor

    DOEpatents

    Nelson, R.T.; Middleton, M.G.

    1983-01-25

    A hermetic refrigeration compressor includes a suction muffler formed from two pieces of plastic material mounted on the cylinder housing. One piece is cylindrical in shape with an end wall having an aperture for receiving a suction tube connected to the cylinder head. The other piece fits over and covers the other end of the cylindrical piece, and includes a flaring entrance horn which extends toward the return line on the sidewall of the compressor shell. 5 figs.

  20. Titanium hermetic seals

    DOEpatents

    Brow, Richard K.; Watkins, Randall D.

    1995-07-04

    Titanium is prenitrided by being heated in a nitrogen environment under conditions which give rise to the formation of a titanium-nitride surface layer on the titanium. Titanium thus prenitrided may be used in electrical components which are hermetically sealed using silicate glasses and standard glass sealing techniques. According to the method of the invention, alkali volatilization and formation of deleterious interfacial silicide are inhibited.

  1. Titanium hermetic seals

    DOEpatents

    Brow, Richard K.; Watkins, Randall D.

    1995-01-01

    Titanium is prenitrided by being heated in a nitrogen environment under conditions which give rise to the formation of a titanium-nitride surface layer on the titanium. Titanium thus prenitrided may be used in electrical components which are hermetically sealed using silicate glasses and standard glass sealing techniques. According to the method of the invention, alkali volatilization and formation of deleterious interfacial silicide are inhibited.

  2. Hermetic turbine generator

    DOEpatents

    Meacher, John S.; Ruscitto, David E.

    1982-01-01

    A Rankine cycle turbine drives an electric generator and a feed pump, all on a single shaft, and all enclosed within a hermetically sealed case. The shaft is vertically oriented with the turbine exhaust directed downward and the shaft is supported on hydrodynamic fluid film bearings using the process fluid as lubricant and coolant. The selection of process fluid, type of turbine, operating speed, system power rating, and cycle state points are uniquely coordinated to achieve high turbine efficiency at the temperature levels imposed by the recovery of waste heat from the more prevalent industrial processes.

  3. Dual capacity compressor with reversible motor and controls arrangement therefor

    DOEpatents

    Sisk, Francis J.

    1980-12-02

    A hermetic reciprocating compressor such as may be used in heat pump applications is provided for dual capacity operation by providing the crankpin of the crankshaft with an eccentric ring rotatably mounted thereon, and with the end of the connecting rod opposite the piston encompassing the outer circumference of the eccentric ring, with means limiting the rotation of the eccentric ring upon the crankpin between one end point and an opposite angularly displaced end point to provide different values of eccentricity depending upon which end point the eccentric ring is rotated to upon the crankpin, and a reversible motor in the hermetic shell of the compressor for rotating the crankshaft, the motor operating in one direction effecting the angular displacement of the eccentric ring relative to the crankpin to the one end point, and in the opposite direction effecting the angular displacement of the eccentric ring relative to the crankpin to the opposite end point, this arrangement automatically giving different stroke lengths depending upon the direction of motor rotation. The mechanical structure of the arrangement may take various forms including at least one in which any impact of reversal is reduced by utilizing lubricant passages and chambers at the interface area of the crankpin and eccentric ring to provide a dashpot effect. In the main intended application of the arrangement according to the invention, that is, in a refrigerating or air conditioning system, it is desirable to insure a delay during reversal of the direction of compressor operation. A control arrangement is provided in which the control system controls the direction of motor operation in accordance with temperature conditions, the system including control means for effecting operation in a low capacity direction or alternatively in a high capacity direction in response to one set, and another set, respectively, of temperature conditions and with timer means delaying a restart of the compressor

  4. Hermetic Seal Leak Detection Apparatus

    NASA Technical Reports Server (NTRS)

    Kelley, Anthony R. (Inventor)

    2013-01-01

    The present invention is a hermetic seal leak detection apparatus, which can be used to test for hermetic seal leaks in instruments and containers. A vacuum tight chamber is created around the unit being tested to minimize gas space outside of the hermetic seal. A vacuum inducing device is then used to increase the gas chamber volume inside the device, so that a slight vacuum is pulled on the unit being tested. The pressure in the unit being tested will stabilize. If the stabilized pressure reads close to a known good seal calibration, there is not a leak in the seal. If the stabilized pressure reads closer to a known bad seal calibration value, there is a leak in the seal. The speed of the plunger can be varied and by evaluating the resulting pressure change rates and final values, the leak rate/size can be accurately calculated.

  5. Numerical Investigation of Flow Losses through Discharge Line of Household Type Refrigerator Compressors

    NASA Astrophysics Data System (ADS)

    Yesilaydin, I.; Erbay, L. B.

    2015-08-01

    The technological developments, competition and energy policies are forcing the refrigeration market to increase the efficiency of their products as never before. The component that determines the performance and efficiency of the refrigeration system is the compressor, which is the major energy consumer in a compression refrigeration system. One of the essential elements of the total compressor efficiency is the discharge line flow efficiency that is subjected to this study. In this paper, the effects of design parameters on flow loses at discharge line of a hermetic reciprocating compressor were investigated with numerical flow analysis. At this study, three conceptual designs were modelled based on the discharge line design parameters such as line diameter, resonator volumes and line length. The pressure drop regions are determined by CFD analyses and they compared against the base model. Analyses are carried out by using commercial CFD software. Furthermore, the obtained numerical results were compared to experimental data and presented a good agreement in terms of pressure drop and discharge line flow efficiency.

  6. Self-Rupturing Hermetic Valve

    NASA Technical Reports Server (NTRS)

    Tucker, Curtis E., Jr.; Sherrit, Stewart

    2011-01-01

    For commercial, military, and aerospace applications, low-cost, small, reliable, and lightweight gas and liquid hermetically sealed valves with post initiation on/off capability are highly desirable for pressurized systems. Applications include remote fire suppression, single-use system-pressurization systems, spacecraft propellant systems, and in situ instruments. Current pyrotechnic- activated rupture disk hermetic valves were designed for physically larger systems and are heavy and integrate poorly with portable equipment, aircraft, and small spacecraft and instrument systems. Additionally, current pyrotechnically activated systems impart high g-force shock loads to surrounding components and structures, which increase the risk of damage and can require additional mitigation. The disclosed mechanism addresses the need for producing a hermetically sealed micro-isolation valve for low and high pressure for commercial, aerospace, and spacecraft applications. High-precision electrical discharge machining (EDM) parts allow for the machining of mated parts with gaps less than a thousandth of an inch. These high-precision parts are used to support against pressure and extrusion, a thin hermetically welded diaphragm. This diaphragm ruptures from a pressure differential when the support is removed and/or when the plunger is forced against the diaphragm. With the addition of conventional seals to the plunger and a two-way actuator, a derivative of this design would allow nonhermetic use as an on/off or metering valve after the initial rupturing of the hermetic sealing disk. In addition, in a single-use hermetically sealed isolation valve, the valve can be activated without the use of potential leak-inducing valve body penetrations. One implementation of this technology is a high-pressure, high-flow-rate rupture valve that is self-rupturing, which is advantageous for high-pressure applications such as gas isolation valves. Once initiated, this technology is self

  7. Hermetic G-16 percussion primer

    SciTech Connect

    Durand, N.A.; Weinmaster, R.R.; Massis, T.M.

    1988-01-01

    Studies were conducted to optimize a Hermetic percussion primer capable of surviving temperatures of 200/degree/C for up to 48 hours. These studies included work with typical brass percussion primers and the pyrotechnic composition designed G-16. The G-16 mixture is composed of antimony sulfide, calcium silicide, and potassium. The hermetically sealed assembly consists of a brass cup and anvil loaded with G-16 pyrotechnic mixture and assembly includes a steel disc which is laser welded over the sealing mechanisms cause negligible changes. This assembly can be used with other primers and is capable of enhanced output for specialized applications. 4 refs., 8 figs., 4 tabs.

  8. Cooled spool piston compressor

    NASA Technical Reports Server (NTRS)

    Morris, Brian G. (Inventor)

    1993-01-01

    A hydraulically powered gas compressor receives low pressure gas and outputs a high pressure gas. The housing of the compressor defines a cylinder with a center chamber having a cross-sectional area less than the cross-sectional area of a left end chamber and a right end chamber, and a spool-type piston assembly is movable within the cylinder and includes a left end closure, a right end closure, and a center body that are in sealing engagement with the respective cylinder walls as the piston reciprocates. First and second annual compression chambers are provided between the piston enclosures and center housing portion of the compressor, thereby minimizing the spacing between the core gas and a cooled surface of the compressor. Restricted flow passageways are provided in the piston closure members and a path is provided in the central body of the piston assembly, such that hydraulic fluid flows through the piston assembly to cool the piston assembly during its operation. The compressor of the present invention may be easily adapted for a particular application, and is capable of generating high gas pressures while maintaining both the compressed gas and the compressor components within acceptable temperature limits.

  9. Glassy composition for hermetic seals

    DOEpatents

    Wilder, Jr., James A.

    1980-01-01

    The invention relates to a glassy composition adaptable for sealing to aluminum-based alloys to form a hermetically-sealed insulator body. The composition may either be employed as a glass or, after devitrifying heat treatment, as a glass-ceramic.

  10. Semi-active compressor valve

    DOEpatents

    Brun, Klaus; Gernentz, Ryan S.

    2010-07-27

    A method and system for fine-tuning the motion of suction or discharge valves associated with cylinders of a reciprocating gas compressor, such as the large compressors used for natural gas transmission. The valve's primary driving force is conventional, but the valve also uses an electromagnetic coil to sense position of the plate (or other plugging element) and to provide an opposing force prior to impact.

  11. Best compression: Reciprocating or rotary?

    SciTech Connect

    Cahill, C.

    1997-07-01

    A compressor is a device used to increase the pressure of a compressible fluid. The inlet pressure can vary from a deep vacuum to a high positive pressure. The discharge pressure can range from subatmospheric levels to tens of thousands of pounds per square inch. Compressors come in numerous forms, but for oilfield applications there are two primary types, reciprocating and rotary. Both reciprocating and rotary compressors are grouped in the intermittent mode of compression. Intermittent is cyclic in nature, in that a specific quantity of gas is ingested by the compressor, acted upon and discharged before the cycle is repeated. Reciprocating compression is the most common form of compression used for oilfield applications. Rotary screw compressors have a long history but are relative newcomers to oilfield applications. The rotary screw compressor-technically a helical rotor compressor-dates back to 1878. That was when the first rotary screw was manufactured for the purpose of compressing air. Today thousands of rotary screw compression packages are being used throughout the world to compress natural gas.

  12. Method of making hermetic seals for hermetic terminal assemblies

    DOEpatents

    Hsu, John S.; Marlino, Laura D.; Ayers, Curtis W.

    2010-04-13

    This invention teaches methods of making a hermetic terminal assembly comprising the steps of: inserting temporary stops, shims and jigs on the bottom face of a terminal assembly thereby blocking assembly core open passageways; mounting the terminal assembly inside a vacuum chamber using a temporary assembly perimeter seal and flange or threaded assembly interfaces; mixing a seal admixture and hardener in a mixer conveyor to form a polymer seal material; conveying the polymer seal material into a polymer reservoir; feeding the polymer seal material from the reservoir through a polymer outlet valve and at least one polymer outlet tube into the terminal assembly core thereby filling interstitial spaces in the core adjacent to service conduits, temporary stop, and the terminal assembly casing; drying the polymer seal material at room temperature thereby hermetically sealing the core of the terminal assembly; removing the terminal assembly from the vacuum chamber, and; removing the temporary stops, shims.

  13. 40 CFR 60.482-3a - Standards: Compressors.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Administrator. (j) Any existing reciprocating compressor in a process unit which becomes an affected facility... 40 Protection of Environment 6 2010-07-01 2010-07-01 false Standards: Compressors. 60.482-3a..., Reconstruction, or Modification Commenced After November 7, 2006 § 60.482-3a Standards: Compressors. (a)...

  14. Customized Hermetic Feedthrough Developed to Isolate Fluids

    NASA Technical Reports Server (NTRS)

    Meredith, Roger D.

    1999-01-01

    A common problem occurs when refrigerant fluids wick inside the insulation of thermocouple wires through a compressor's casing feedthrough and then leak into the adjacent disconnect box outside the casing. Leaking fluids create an unfavorable situation inside the disconnect box and may contaminate the fluids. To address this problem, NASA Lewis Research Center s Manufacturing Engineering Division developed a customized hermetic feedthrough for a bank of Worthington compressors. In these compressors, bearing temperatures are measured by internal thermocouples embedded in bearings located inside the compressor casings. The thermocouple wires need to be routed outside the casing and read at another location. These wires are short and are terminated to a disconnect strip inside the casing. The bearings operate at about 170 F, but because the casing is filled with R12 refrigerant oil, the casing has a maximum temperature of about 100 F. The operating conditions of these compressors permit the use of an epoxy that is compatible with the R12 fluid. The desired finished product is a stainless steel tube that has been filled solid with epoxy after thermocouple wires bonded and sealed by epoxy have been inserted through its length. Shrink tubing extends from both ends of the tube. The process that was developed to isolate the thermocouple wires from the R12 fluid follows. For this application, use an 8-in.-long piece of 0.500-in. 304 stainless steel tube with six pairs of 24-gauge stranded, PTFE-insulated (polytetrafluoroethylene) type "T" thermocouple wires for each feedthrough. Use shrink tubing to strain relief the insulated wires at their exit from the stainless steel tube. Cut the wire to length and identify the location of the stainless steel tube sleeve with masking tape. Then, remove the outer insulation from a 2-in. section of wire that will be inside the tube, and carefully strip to bare wire a 1-in. section in the middle of the section with the outer insulation

  15. Method for hermetic electrical connections

    DOEpatents

    Monroe, Saundra L.; Glass, S. Jill; Stone, Ronnie G.; Bond, Jamey T.; Susan, Donald F.

    2011-12-27

    A method of providing a hermetic, electrical connection between two electrical components by mating at least one metal pin in a glass-ceramic to metal seal connector to two electrical components, wherein the glass-ceramic to metal seal connector incorporates at least one metal pin encased (sealed) in a glass-ceramic material inside of a metal housing, with the glass-ceramic material made from 65-80% SiO.sub.2, 8-16% Li.sub.2O, 2-8% Al.sub.2O.sub.3, 1-5% P.sub.2O.sub.5, 1-8% K.sub.2O, 0.5-7% B.sub.2O.sub.3, and 0-5% ZnO. The connector retains hermeticity at temperatures as high as 700.degree. C. and pressures as high as 500 psi.

  16. Hermetically sealed superconducting magnet motor

    DOEpatents

    DeVault, R.C.; McConnell, B.W.; Phillips, B.A.

    1996-07-02

    A hermetically sealed superconducting magnet motor includes a rotor separated from a stator by either a radial gap, an axial gap, or a combined axial and radial gap. Dual conically shaped stators are used in one embodiment to levitate a disc-shaped rotor made of superconducting material within a conduit for moving cryogenic fluid. As the rotor is caused to rotate when the field stator is energized, the fluid is pumped through the conduit. 6 figs.

  17. Hermetically sealed superconducting magnet motor

    DOEpatents

    DeVault, Robert C.; McConnell, Benjamin W.; Phillips, Benjamin A.

    1996-01-01

    A hermetically sealed superconducting magnet motor includes a rotor separated from a stator by either a radial gap, an axial gap, or a combined axial and radial gap. Dual conically shaped stators are used in one embodiment to levitate a disc-shaped rotor made of superconducting material within a conduit for moving cryogenic fluid. As the rotor is caused to rotate when the field stator is energized, the fluid is pumped through the conduit.

  18. Reciprocating piston engine

    SciTech Connect

    Eickmann, K.

    1986-01-07

    This patent describes a reciprocating combustion engine consisting of a cylinder, a piston reciprocating in the cylinder, a top for closing one end of the cylinder, inlets and outlets extending to and from the cylinder for the intake of combustible gas and the expelling of burned exhaust gases. The engine also consists of a device for ignition of the combustible gas, a means of cooling the cylinder and top, a turbine of a turbocharger connected to the outlet, and a compressor of the turbocharger connected to the inlet.

  19. Hermetic seal for a shaft

    NASA Technical Reports Server (NTRS)

    Lombardi, F. (Inventor)

    1982-01-01

    An hermetic seal for a linear rod having a portion thereof projected axially through a port defined in a wall for a pressure chamber and supported thereby for omni-directional motion is described. The seal is characterized by a resilient, impervious, cylindrical body having a first section concentrically related to the shaft and integrally affixed thereto comprising a linear ordered array of annular flutes. A second section integrally is affixed to the wall of the chamber and concentrically related to the port comprising a second linear ordered array of annular flutes. A third section is interposed between the first and second sections and integrally affixed in coaxial alignment therewith comprising an annular ordered array of linear flutes concentrically related to the shaft, whereby axial, angular, and pivotal motion of the rod is accommodated.

  20. Method for forming hermetic seals

    NASA Technical Reports Server (NTRS)

    Gallagher, Brian D.

    1987-01-01

    The firmly adherent film of bondable metal, such as silver, is applied to the surface of glass or other substrate by decomposing a layer of solution of a thermally decomposable metallo-organic deposition (MOD) compound such as silver neodecanoate in xylene. The MOD compound thermally decomposes into metal and gaseous by-products. Sealing is accomplished by depositing a layer of bonding metal, such as solder or a brazing alloy, on the metal film and then forming an assembly with another high melting point metal surface such as a layer of Kovar. When the assembly is heated above the temperature of the solder, the solder flows, wets the adjacent surfaces and forms a hermetic seal between the metal film and metal surface when the assembly cools.

  1. Hermetic edge sealing of photovoltaic modules

    NASA Technical Reports Server (NTRS)

    1983-01-01

    The edge sealing technique is accomplished by a combination of a chemical bond between glass and aluminum, formed by electrostatic bonding, and a metallurgical bond between aluminum and aluminum, formed by ultrasonic welding. Such a glass to metal seal promises to provide a low cost, long lifetime, highly effective hermetic seal which can protect module components from severe environments. Development of the sealing techniques and demonstration of their effectiveness by fabricating a small number of dummy modules, up to eight inches square in size, and testing them for hermeticity using helium leak testing methods are reviewed. Non-destructive test methods are investigated.

  2. Hermetic packaging for microwave modules. Final report

    SciTech Connect

    Hollar, D.L.

    1996-10-01

    Microwave assemblies, such as radar modules, require hermetically sealed packaging. Since most of these assemblies are used for airborne applications, the packages must be lightweight. The aluminum alloy A-40 provides the needed characteristics of these applications. This project developed packaging techniques using the A-40 alloy as a housing material and laser welding processes to install connectors, purge tube, and covers on the housings. The completed package successfully passed the hermetic leak requirements and environmental testing. Optimum laser welding parameters were established in addition to all of the related tooling for assembly.

  3. Linear Motor Free Piston Compressor

    NASA Astrophysics Data System (ADS)

    Bloomfield, David P.

    1995-02-01

    A Linear Motor Free Piston Compressor (LMFPC), a free piston pressure recovery system for fuel cell powerplants was developed. The LMFPC consists of a reciprocating compressor and a reciprocating expander which are separated by a piston. In the past energy efficient turbochargers have been used for pressure large (over 50 kW) fuel cell powerplants by recovering pressure energy from the powerplant exhaust. A free piston compressor allows pressurizing 3 - 5 kW sized fuel cell powerplants. The motivation for pressurizing PEM fuel cell powerplants is to improve fuel cell performance. Pressurization of direct methanol fuel cells will be required if PEM membranes are to be used Direct methanol oxidation anode catalysts require high temperatures to operate at reasonable power densities. The elevated temperatures above 80 C will cause high water loss from conventional PEM membranes unless pressurization is employed. Because pressurization is an energy intensive process, recovery of the pressure energy is required to permit high efficiency in fuel cell powerplants. A complete LMFPC which can pressurize a 3 kW fuel cell stack was built. This unit is one of several that were constructed during the course of the program.

  4. Hydride compressor

    DOEpatents

    Powell, James R.; Salzano, Francis J.

    1978-01-01

    Method of producing high energy pressurized gas working fluid power from a low energy, low temperature heat source, wherein the compression energy is gained by using the low energy heat source to desorb hydrogen gas from a metal hydride bed and the desorbed hydrogen for producing power is recycled to the bed, where it is re-adsorbed, with the recycling being powered by the low energy heat source. In one embodiment, the adsorption-desorption cycle provides a chemical compressor that is powered by the low energy heat source, and the compressor is connected to a regenerative gas turbine having a high energy, high temperature heat source with the recycling being powered by the low energy heat source.

  5. Supersonic compressor

    DOEpatents

    Lawlor, Shawn P.; Novaresi, Mark A.; Cornelius, Charles C.

    2008-02-26

    A gas compressor based on the use of a driven rotor having an axially oriented compression ramp traveling at a local supersonic inlet velocity (based on the combination of inlet gas velocity and tangential speed of the ramp) which forms a supersonic shockwave axially, between adjacent strakes. In using this method to compress inlet gas, the supersonic compressor efficiently achieves high compression ratios while utilizing a compact, stabilized gasdynamic flow path. Operated at supersonic speeds, the inlet stabilizes an oblique/normal shock system in the gasdyanamic flow path formed between the gas compression ramp on a strake, the shock capture lip on the adjacent strake, and captures the resultant pressure within the stationary external housing while providing a diffuser downstream of the compression ramp.

  6. Glass-ceramic composition for hermetic seals

    DOEpatents

    Ballard, Jr., Clifford P.

    1979-01-01

    The invention relates to a glass-ceramic composition having a high fracture strength adaptable for hermetically sealing to chromium bearing iron or nickel base alloys at temperatures of between about 950.degree. C to about 1100.degree. C to form a hermetically sealed insulator body, comprising from about 55 to about 65 weight percent SiO.sub.2, from about 0 to about 5 weight percent Al.sub.2 O.sub.3, from about 6 to about 11 weight % Li.sub.2 O, from about 25 to about 32 weight percent BaO, from about 0.5 to about 1.0 weight percent CoO and from about 1.5 to about 3.5 weight percent P.sub.2 O.sub.5.

  7. Shrink-Fit Solderable Inserts Seal Hermetically

    NASA Technical Reports Server (NTRS)

    Croucher, William C.

    1992-01-01

    Shrink-fit stainless-steel insert in aluminum equipment housing allows electrical connectors to be replaced by soldering, without degrading hermeticity of housing or connector. Welding could destroy electrostatic-sensitive components and harm housing and internal cables. Steel insert avoids problems because connector soldered directly to it rather than welded to housing. Seals between flange and housing, and between connector and flange resistant to leaks, even after mechanical overloading and thermal shocking.

  8. Evaluation of Polymer Hermetically Sealed Tantalum Capacitors

    NASA Technical Reports Server (NTRS)

    Teverovsky, Alexander A.

    2014-01-01

    Polymer cathode tantalum capacitors have lower ESR (equivalent series resistance) compared to other types of tantalum capacitors and for this reason have gained popularity in the electronics design community. Their use allows improved performance of power supply systems along with substantial reduction of size and weight of the components used. However, these parts have poor thermal stability and can degrade in humid environments. Polymer hermetically sealed (PHS) capacitors avoid problems related to environmental degradation of molded case parts and can potentially replace current wet and solid hermetically sealed capacitors. In this work, PHS capacitors manufactured per DLA LAM DWG#13030 are evaluated for space applications. Several lots of capacitors manufactured over period from 2010 to 2014 were tested for the consistency of performance, electrical and thermal characteristics, highly accelerated life testing, and robustness under reverse bias and random vibration conditions. Special attention was given to analysis of leakage currents and the effect of long-term high temperature storage on capacitors in as is condition and after hermeticity loss. The results show that PHS capacitors might be especially effective for low-temperature applications or for system requiring a cold start-up. Additional screening and qualification testing have been recommended to assure the necessary quality of capacitors for space projects.

  9. Supersonic compressor

    DOEpatents

    Roberts, II, William Byron; Lawlor, Shawn P.; Breidenthal, Robert E.

    2016-04-12

    A supersonic compressor including a rotor to deliver a gas at supersonic conditions to a diffuser. The diffuser includes a plurality of aerodynamic ducts that have converging and diverging portions, for deceleration of gas to subsonic conditions and then for expansion of subsonic gas, to change kinetic energy of the gas to static pressure. The aerodynamic ducts include vortex generating structures for controlling boundary layer, and structures for changing the effective contraction ratio to enable starting even when the aerodynamic ducts are designed for high pressure ratios, and structures for boundary layer control. In an embodiment, aerodynamic ducts are provided having an aspect ratio of in excess of two to one, when viewed in cross-section orthogonal to flow direction at an entrance to the aerodynamic duct.

  10. Electromagnetic Reciprocity.

    SciTech Connect

    Aldridge, David F.

    2014-11-01

    A reciprocity theorem is an explicit mathematical relationship between two different wavefields that can exist within the same space - time configuration. Reciprocity theorems provi de the theoretical underpinning for mod ern full waveform inversion solutions, and also suggest practical strategies for speed ing up large - scale numerical modeling of geophysical datasets . In the present work, several previously - developed electromagnetic r eciprocity theorems are generalized to accommodate a broader range of medi um, source , and receiver types. Reciprocity relations enabling the interchange of various types of point sources and point receivers within a three - dimensional electromagnetic model are derived. Two numerical modeling algorithms in current use are successfully tested for adherence to reciprocity. Finally, the reciprocity theorem forms the point of departure for a lengthy derivation of electromagnetic Frechet derivatives. These mathe matical objects quantify the sensitivity of geophysical electromagnetic data to variatio ns in medium parameters, and thus constitute indispensable tools for solution of the full waveform inverse problem. ACKNOWLEDGEMENTS Sandia National Labor atories is a multi - program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the US Department of Energy's National Nuclear Security Administration under contract DE - AC04 - 94AL85000. Signif icant portions of the work reported herein were conducted under a Cooperative Research and Development Agreement (CRADA) between Sandia National Laboratories (SNL) and CARBO Ceramics Incorporated. The author acknowledges Mr. Chad Cannan and Mr. Terry Pa lisch of CARBO Ceramics, and Ms. Amy Halloran, manager of SNL's Geophysics and Atmospheric Sciences Department, for their interest in and encouragement of this work. Special thanks are due to Dr . Lewis C. Bartel ( recently retired from Sandia National Labo ratories and now a

  11. Hermetic optical-fiber iodine frequency standard.

    PubMed

    Light, Philip S; Anstie, James D; Benabid, Fetah; Luiten, Andre N

    2015-06-15

    We have built an optical-frequency standard based on interrogating iodine vapor that has been trapped within the hollow core of a hermetically sealed kagome-lattice photonic crystal fiber. A frequency-doubled Nd:YAG laser locked to a hyperfine component of the P(142)37-0 I2127 transition using modulation transfer spectroscopy shows a frequency stability of 3×10(-11) at 100 s. We discuss the impediments in integrating this all-fiber standard into a fully optical-fiber-based system, and suggest approaches that could improve performance of the frequency standard substantially.

  12. Reciprocal translocations

    SciTech Connect

    1993-12-31

    Chapter 26, describes reciprocal translocations of chromosomes: their occurrence, breakpoints, and multiple rearrangements. In addition, phenotypes of balanced and unbalanced translocation carriers and fetal death are discussed. Examples of translocation families are given. Meiosis and genetic risk in translocation carriers is presented. Finally, sperm chromosomes in meiotic segregation analysis is mentioned. 39 refs., 3 figs., 1 tab.

  13. Corrosion in Non-Hermetic Microelectronic Devices

    SciTech Connect

    Braithwaite, J.W.; Sorensen, N.R.

    1999-03-16

    Many types of integrated and discrete microelectronic devices exist in the enduring stockpile. In the past, most of these devices have used conventional ceramic hermetic packaging (CHP) technology. Sometime in the future, plastic encapsulated microelectronic (PEM) devices will almost certainly enter the inventory. In the presence of moisture, several of the aluminum-containing metallization features common to both types of packaging become susceptible to atmospheric corrosion (Figure 1). A breach in hermeticity (e.g., due to a crack in the ceramic body or lid seal) could allow moisture and/or contamination to enter the interior of a CHP device. For PEM components, the epoxy encapsulant material is inherently permeable to moisture. A multi-year project is now underway at Sandia to develop the knowledge base and analytical tools needed to quantitatively predict the effect of corrosion on microelectronic performance and reliability. The issue of corrosion-induced failure surfaced twice during the past year because cracks were found in their ceramic bodies of two different CHP devices: the SA371 1/3712 MOSFET and the SA3935 ASIC (acronym for A Simple Integrated Circuit). Because of our inability to perform a model-based prediction at that time, the decision was made to determine the validity of the corrosion concern for these specific situations by characterizing the expected environment and assessing its relative degree of corrosivity. The results of this study are briefly described in this paper along with some of the advancements made with the predictive model development.

  14. Method for forming hermetic coatings for optical fibers

    SciTech Connect

    Michalske, Terry A.; Rye, Robert R.; Smith, William L.

    1993-01-01

    A method for forming hermetic coatings on optical fibers by hot filament assisted chemical vapor deposition advantageously produces a desirable coating while maintaining the pristine strength of the pristine fiber. The hermetic coatings may be formed from a variety of substances, such as, for example, boron nitride and carbon.

  15. Hermetically sealed galvanic cell having safety vent construction

    SciTech Connect

    Chaney, E.J. Jr.

    1984-12-04

    An hermetically sealed galvanic cell having a safety vent assembly comprising a housing having a portion which is inwardly depressed and flexible, which portion surrounds an aperture. The aperture is filled with a layer of glass or ceramic material thus producing an hermetically sealed cell which exhibits increased mechanical strength coupled with reliable venting.

  16. Hydrogen pipeline compressors annual progress report.

    SciTech Connect

    Fenske, G. R.; Erck, R. A.

    2011-07-15

    The objectives are: (1) develop advanced materials and coatings for hydrogen pipeline compressors; (2) achieve greater reliability, greater efficiency, and lower capital in vestment and maintenance costs in hydrogen pipeline compressors; and (3) research existing and novel hydrogen compression technologies that can improve reliability, eliminate contamination, and reduce cost. Compressors are critical components used in the production and delivery of hydrogen. Current reciprocating compressors used for pipeline delivery of hydrogen are costly, are subject to excessive wear, have poor reliability, and often require the use of lubricants that can contaminate the hydrogen (used in fuel cells). Duplicate compressors may be required to assure availability. The primary objective of this project is to identify, and develop as required, advanced materials and coatings that can achieve the friction, wear, and reliability requirements for dynamically loaded components (seal and bearings) in high-temperature, high-pressure hydrogen environments prototypical of pipeline and forecourt compressor systems. The DOE Strategic Directions for Hydrogen Delivery Workshop identified critical needs in the development of advanced hydrogen compressors - notably, the need to minimize moving parts and to address wear through new designs (centrifugal, linear, guided rotor, and electrochemical) and improved compressor materials. The DOE is supporting several compressor design studies on hydrogen pipeline compression specifically addressing oil-free designs that demonstrate compression in the 0-500 psig to 800-1200 psig range with significant improvements in efficiency, contamination, and reliability/durability. One of the designs by Mohawk Innovative Technologies Inc. (MiTi{reg_sign}) involves using oil-free foil bearings and seals in a centrifual compressor, and MiTi{reg_sign} identified the development of bearings, seals, and oil-free tribological coatings as crucial to the successful

  17. Integral window hermetic fiber optic components

    SciTech Connect

    Dalton, R.D.; Kramer, D.P.; Massey, R.T.; Waker, D.A.

    1994-12-31

    In the fabrication of igniters, actuators, detonators, and other pyrotechnic devices to be activated by a laser beam, an integral optical glass window is formed by placing a preform in the structural member of the device and then melting the glass and sealing it in place by heating at a temperature between the ceramming temperature of the glass and the melting point of the metal, followed by rapid furnace cooling to avoid devitrification. No other sealing material is needed to achieve hermeticity. A preferred embodiment of this type of device is fabricated by allowing the molten glass to flow further and form a plano-convex lens integral with and at the bottom of the window. The lens functions to decrease the beam divergence caused by refraction of the laser light passing through the window when the device is fired by means of a laser beam.

  18. SLM Produced Hermetically Sealed Isolation Valve

    NASA Technical Reports Server (NTRS)

    Richard, James

    2014-01-01

    Marshall Space Flight Center (MSFC) has developed a valve concept to replace traditional pyrotechnic-driven isolation valves. This paper will describe the valve design and development process. The valve design uses a stem/wedge to support a disk inside the valve. That disk hermetically seals the pressurized fluids. A release mechanism holds the stem/wedge and a large spring in place. When required to open, a solenoid is energized and pulls the release mechanism allowing the spring to pull the stem/wedge away from the disk. Now the disk is unsupported and the pressure ruptures the disk allowing flow to the outlet of the valve. This paper will provide details of this design, describe the development testing, and show the results from the valve level tests performed. Also, a trade study is presented to show the advantages of this design to a conventional pyrotechnic-based valve.

  19. SLM Produced Hermetically Sealed Isolation Valve

    NASA Technical Reports Server (NTRS)

    Richard, James A.

    2014-01-01

    Marshall Space Flight Center (MSFC) has developed a valve concept to replace traditional pyrotechnic driven isolation valves. This paper will describe the valve design and development process. The valve design uses a stem/wedge to support a disk inside the valve. That disk hermetically seals the pressurized fluids. A release mechanism holds the stem/wedge and a large spring in place. When required to open, a solenoid is energized and pulls the release mechanism allowing the spring to pull the stem/wedge away from the disk. Now the disk is unsupported and the pressure ruptures the disk allowing flow to the outlet of the valve. This paper will provide details of this design, describe the development testing, and show the results from the valve level tests performed. Also, a trade study is presented to show the advantages of this design to a conventional pyrotechnic based valve.

  20. TFE coating extends life of flexible metal compressor diaphragm

    NASA Technical Reports Server (NTRS)

    Gorland, S.

    1970-01-01

    Tetrafluoroethylene /TFE/ aerosol sprayed onto entire surface of diaphragm acts as film lubricant and permits diaphragm to slide between upper and lower plates in a reciprocating compressor. Flexing occurs over an area rather than about a single line of action and operating life of diaphragm is more than quadrupled.

  1. 66. VIEW, LOOKING EAST, OF AIR COMPRESSOR LOCATED IN CONDENSER ...

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

    66. VIEW, LOOKING EAST, OF AIR COMPRESSOR LOCATED IN CONDENSER GALLERY BELOW TURBINE HALL. THIS UNIT WAS POWERED BY A RECIPROCATING STEAM ENGINE AND WAS PART OF THE ORIGINAL PLANT MACHINERY. - New York, New Haven & Hartford Railroad, Cos Cob Power Plant, Sound Shore Drive, Greenwich, Fairfield County, CT

  2. A miniature Rotary Compressor with a 1:10 compression ratio

    NASA Astrophysics Data System (ADS)

    Dmitriev, Olly; Tabota, Eugene; Arbon EurIng, Ian; FIMechE, CEng

    2015-08-01

    Micro compressors have applications in medical devices, robotics and “nanosatellites”. The problem of active cooling for photo detectors in “nano-satellites” becomes more important because the majority of space missions target Earth observation, and passive cooling does not provide the required temperatures to achieve the desired SNR levels. Reciprocating compressors used in cryocoolers cause vibrations. VERT Rotors has built an ultralow-vibration rotary compressor with 40mm-long screws, and our prototype delivered 1:10 compression ratio. This “nano” compressor is a non-conventional conical type consisting of an Inner conical screw rotor revolving inside an Outer screw rotor.

  3. Remote fluorescence lifetime inspection of hermeticity of packaged food containers

    NASA Astrophysics Data System (ADS)

    Mendoza, Edgar A.; Kempen, Cornelia; Sun, Sunjian; Esterkin, Yan

    2014-09-01

    This paper describes recent progress towards the development of a remote "frequency-domain" fluorescence lifetime (SeePhase™) monitor used for the real time hermetic seal leak inspection of packaged food containers. A multitude of food goods, meets, vegetables, and beverages are typically packaged within an inert environment to reduce the risk of bacteria growth and increase the storage life of the food product. The SeePhase™ system uses a multi-parameter oxygen, carbon dioxide, and moisture sensitive patch that is placed within the hermetic sealed food package. Upon the presence of gases oxygen, carbon dioxide, or moisture inside the hermetic sealed food package, the sensor patch produces a fluorescence lifetime signature characteristic of a hermetic seal leak damage of the package.

  4. Hermetic Seal Leak Detection Apparatus with Variable Size Test Chamber

    NASA Technical Reports Server (NTRS)

    Kelley, Anthony R. (Inventor)

    2015-01-01

    The present invention is a versatile hermetic seal leak detection apparatus for testing hermetically sealed containers and devices for leaks without the need to create a custom or specially manufactured testing chamber conforming to the dimensions of the specific object under test. The size of the testing chamber may be mechanically adjusted by the novel use of bellows to reduce and optimize the amount of gas space in a test chamber which surrounds the hermetically sealed object under test. The present invention allows the size of the test chamber to be selectively adjusted during testing to provide an optimum test chamber gas space. The present invention may be further adapted to isolate and test specific portions of the hermetically sealed object under test for leaks.

  5. Development Of A Centrifugal Hydrogen Pipeline Gas Compressor

    SciTech Connect

    Di Bella, Francis A.

    2015-04-16

    Concepts NREC (CN) has completed a Department of Energy (DOE) sponsored project to analyze, design, and fabricate a pipeline capacity hydrogen compressor. The pipeline compressor is a critical component in the DOE strategy to provide sufficient quantities of hydrogen to support the expected shift in transportation fuels from liquid and natural gas to hydrogen. The hydrogen would be generated by renewable energy (solar, wind, and perhaps even tidal or ocean), and would be electrolyzed from water. The hydrogen would then be transported to the population centers in the U.S., where fuel-cell vehicles are expected to become popular and necessary to relieve dependency on fossil fuels. The specifications for the required pipeline hydrogen compressor indicates a need for a small package that is efficient, less costly, and more reliable than what is available in the form of a multi-cylinder, reciprocating (positive displacement) compressor for compressing hydrogen in the gas industry.

  6. Recirculating rotary gas compressor

    DOEpatents

    Weinbrecht, John F.

    1992-01-01

    A positive displacement, recirculating Roots-type rotary gas compressor which operates on the basis of flow work compression. The compressor includes a pair of large diameter recirculation conduits (24 and 26) which return compressed discharge gas to the compressor housing (14), where it is mixed with low pressure inlet gas, thereby minimizing adiabatic heating of the gas. The compressor includes a pair of involutely lobed impellers (10 and 12) and an associated port configuration which together result in uninterrupted flow of recirculation gas. The large diameter recirculation conduits equalize gas flow velocities within the compressor and minimize gas flow losses. The compressor is particularly suited to applications requiring sustained operation at higher gas compression ratios than have previously been feasible with rotary pumps, and is particularly applicable to refrigeration or other applications requiring condensation of a vapor.

  7. Recirculating rotary gas compressor

    DOEpatents

    Weinbrecht, J.F.

    1992-02-25

    A positive displacement, recirculating Roots-type rotary gas compressor is described which operates on the basis of flow work compression. The compressor includes a pair of large diameter recirculation conduits which return compressed discharge gas to the compressor housing, where it is mixed with low pressure inlet gas, thereby minimizing adiabatic heating of the gas. The compressor includes a pair of involutely lobed impellers and an associated port configuration which together result in uninterrupted flow of recirculation gas. The large diameter recirculation conduits equalize gas flow velocities within the compressor and minimize gas flow losses. The compressor is particularly suited to applications requiring sustained operation at higher gas compression ratios than have previously been feasible with rotary pumps, and is particularly applicable to refrigeration or other applications requiring condensation of a vapor. 12 figs.

  8. Hermetic edge sealing of photovoltaic modules

    NASA Technical Reports Server (NTRS)

    Nowlan, M. J.

    1983-01-01

    The feasibility of using an electrostatic bonding (ESB) and ultrasonic welding process to produce hermetic edge seals on terrestrial solar cell modules was investigated. The fabrication sequence is to attach an aluminum foil "gasket' to the perimeter of a glass sheet. A cell circuit is next encapsulated inside the gasket, and its aluminum foil back cover is seam welded ultrasonically to the gasket. An ESB process for sealing aluminum to glass was developed in an ambient air atmosphere, which eliminates the requirement for a vacuum or pressure vessel. An ultrasonic seam welding process was also developed which did not degrade the quality of the ESB seal. Good quality welds with minimal deformation were produced. The effectiveness of the above described sealing techniques was tested by constructing 400 sq cm (8 x 8 s64 sq in) sample modules, and then subjecting them to nondestructive fine and gross leak tests. The gross leak tests identified several different causes of leaks which were then eliminated by modifying the assembly process.

  9. A Sample Return Container with Hermetic Seal

    NASA Technical Reports Server (NTRS)

    Kong, Kin Yuen; Rafeek, Shaheed; Sadick, Shazad; Porter, Christopher C.

    2000-01-01

    A sample return container is being developed by Honeybee Robotics to receive samples from a derivative of the Champollion/ST4 Sample Acquisition and Transfer Mechanism or other samplers and then hermetically seal samples for a sample return mission. The container is enclosed in a phase change material (PCM) chamber to prevent phase change during return and re-entry to earth. This container is designed to operate passively with no motors and actuators. Using the sampler's featured drill tip for interfacing, transfer-ring and sealing samples, the container consumes no electrical power and therefore minimizes sample temperature change. The circular container houses a few isolated canisters, which will be sealed individually for samples acquired from different sites or depths. The drill based sampler indexes each canister to the sample transfer position, below the index interface for sample transfer. After sample transfer is completed, the sampler indexes a seal carrier, which lines up seals with the openings of the canisters. The sampler moves to the sealing interface and seals the sample canisters one by one. The sealing interface can be designed to work with C-seals, knife edge seals and cup seals. Again, the sampler provides all sealing actuation. This sample return container and co-engineered sample acquisition system are being developed by Honeybee Robotics in collaboration with the JPL Exploration Technology program.

  10. High ratio recirculating gas compressor

    DOEpatents

    Weinbrecht, John F.

    1989-01-01

    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.

  11. Trends in high performance compressors for petrochemical and natural gas industry in China

    NASA Astrophysics Data System (ADS)

    Zhao, Yuanyang; Li, Liansheng

    2015-08-01

    Compressors are the key equipment in the petrochemical and natural gas industry system. The performance and reliability of them are very important for the process system. The application status of petrochemical & natural gas compressors in China is presented in this paper. The present status of design and operating technologies of compressors in China are mentioned in this paper. The turbo, reciprocating and twin screw compressors are discussed. The market demands for different structure compressors in process gas industries are analysed. This paper also introduces the research and developments for high performance compressors in China. The recent research results on efficiency improvement methods, stability improvement, online monitor and fault diagnosis will also be presented in details.

  12. Bidirectional grating compressors

    NASA Astrophysics Data System (ADS)

    Wang, Cheng; Li, Zhaoyang; Li, Shuai; Liu, Yanqi; Leng, Yuxin; Li, Ruxin

    2016-07-01

    A bidirectional grating compressor for chirped pulse amplifiers is presented. It compresses a laser beam simultaneously in two opposite directions. The pulse compressor is shown to promote chirped pulse amplifiers' output energy without grating damages. To verify the practicability, an experiment is carried out. In addition, a crosscorrelation instrument is designed and set up to test the time synchronization between these two femtosecond pulses.

  13. Supersonic gas compressor

    SciTech Connect

    Lawlor, Shawn P.; Novaresi, Mark A.; Cornelius, Charles C.

    2007-11-13

    A gas compressor based on the use of a driven rotor having a compression ramp traveling at a local supersonic inlet velocity (based on the combination of inlet gas velocity and tangential speed of the ramp) which compresses inlet gas against a stationary sidewall. In using this method to compress inlet gas, the supersonic compressor efficiently achieves high compression ratios while utilizing a compact, stabilized gasdynamic flow path. Operated at supersonic speeds, the inlet stabilizes an oblique/normal shock system in the gasdyanamic flow path formed between the rim of the rotor, the strakes, and a stationary external housing. Part load efficiency is enhanced by the use of a pre-swirl compressor, and using a bypass stream to bleed a portion of the intermediate pressure gas after passing through the pre-swirl compressor back to the inlet of the pre-swirl compressor. Inlet guide vanes to the compression ramp enhance overall efficiency.

  14. Chip-scale hermetic feedthroughs for implantable bionics.

    PubMed

    Guenther, Thomas; Dodds, Christopher W D; Lovell, Nigel H; Suaning, Gregg J

    2011-01-01

    Most implantable medical devices such as cochlear implants and visual prostheses require protection of the stimulating electronics. This is achieved by way of a hermetic feedthrough system which typically features three important attributes: biocompatibility with the human body, device hermeticity and density of feedthrough conductors. On the quest for building a visual neuroprosthesis, a high number of stimulating channels is required. This has encouraged new technologies with higher rates of production yield and further miniaturization. An Al(2)O(3) based feedthrough system has been developed comprising up to 20 platinum feedthroughs per square millimeter. Ceramics substrates are shown to have leak rates below 1 × 10(-12) atm × cc/s, thus exceeding the resolution limits of most commercially available leak detectors. A sheet resistance of 0.05 Ω can be achieved. This paper describes the design, fabrication process and hermeticity testing of high density feedthroughs for use in neuroprosthetic implants.

  15. Modeling of an Oil-Free Carbon Dioxide Compressor Using Sanderson-Rocker Arm Motion (S-RAM) Mechanism

    NASA Astrophysics Data System (ADS)

    Yang, Bin; Kurtulus, Orkan; Groll, Eckhard A.

    2015-08-01

    A simulation model to predict the performance of a prototype CO2 compressor is presented. This prototype compressor employs the Sanderson-Rocker Arm Motion (S-RAM) mechanism, which converts the rotary motion of the shaft into a linear reciprocating motion of the cylinders. The piston stroke can be variable by changing the incline angle between the connecting rod and compressor main shaft centerline. The compressor model is mainly composed of two main sub-models simulating the kinematics of the drive mechanism and the compression process. A valve sub-model is included in the compression process model.

  16. Lightweight piston-rod assembly for a reciprocating machine

    DOEpatents

    Corey, John A.; Walsh, Michael M.

    1986-01-01

    In a reciprocating machine, there is provided a hollow piston including a dome portion on one end and a base portion on the opposite end. The base portion includes a central bore into which a rod is hermetically fixed in radial and angular alignment. The extending end of the rod has a reduced diameter portion adapted to fit into the central bore of a second member such as a cross-head assembly, and to be secured thereto in radial and axial alignment with the piston.

  17. β-reciprocal polynomials

    NASA Astrophysics Data System (ADS)

    Withers, Christopher S.; Nadarajah, Saralees

    2016-07-01

    A new class of polynomials pn(x) known as β-reciprocal polynomials is defined. Given a parameter ? that is not a root of -1, we show that the only β-reciprocal polynomials are pn(x) ≡ xn. When β is a root of -1, other polynomials are possible. For example, the Hermite polynomials are i-reciprocal, ?.

  18. Reciprocating pellet press

    DOEpatents

    Jones, Charles W.

    1981-04-07

    A machine for pressing loose powder into pellets using a series of reciprocating motions has an interchangeable punch and die as its only accurately machines parts. The machine reciprocates horizontally between powder receiving and pressing positions. It reciprocates vertically to press, strip and release a pellet.

  19. Compressor map prediction tool

    NASA Astrophysics Data System (ADS)

    Ravi, Arjun; Sznajder, Lukasz; Bennett, Ian

    2015-08-01

    Shell Global Solutions uses an in-house developed system for remote condition monitoring of centrifugal compressors. It requires field process data collected during operation to calculate and assess the machine's performance. Performance is assessed by comparing live results of polytropic head and efficiency versus design compressor curves provided by the Manufacturer. Typically, these design curves are given for specific suction conditions. The further these conditions on site deviate from those prescribed at design, the less accurate the health assessment of the compressor becomes. To address this specified problem, a compressor map prediction tool is proposed. The original performance curves of polytropic head against volumetric flow for varying rotational speeds are used as an input to define a range of Mach numbers within which the non-dimensional invariant performance curve of head and volume flow coefficient is generated. The new performance curves of polytropic head vs. flow for desired set of inlet conditions are then back calculated using the invariant non-dimensional curve. Within the range of Mach numbers calculated from design data, the proposed methodology can predict polytropic head curves at a new set of inlet conditions within an estimated 3% accuracy. The presented methodology does not require knowledge of detailed impeller geometry such as throat areas, blade number, blade angles, thicknesses nor other aspects of the aerodynamic design - diffusion levels, flow angles, etc. The only required mechanical design feature is the first impeller tip diameter. Described method makes centrifugal compressor surveillance activities more accurate, enabling precise problem isolation affecting machine's performance.

  20. Standing wave compressor

    DOEpatents

    Lucas, Timothy S.

    1991-01-01

    A compressor for compression-evaporation cooling systems, which requires no moving parts. A gaseous refrigerant inside a chamber is acoustically compressed and conveyed by means of a standing acoustic wave which is set up in the gaseous refrigerant. This standing acoustic wave can be driven either by a transducer, or by direct exposure of the gas to microwave and infrared sources, including solar energy. Input and output ports arranged along the chamber provide for the intake and discharge of the gaseous refrigerant. These ports can be provided with optional valve arrangements, so as to increase the compressor's pressure differential. The performance of the compressor in either of its transducer or electromagnetically driven configurations, can be optimized by a controlling circuit. This controlling circuit holds the wavelength of the standing acoustical wave constant, by changing the driving frequency in response to varying operating conditions.

  1. Low-temperature hermetic sealing of optical fiber components

    DOEpatents

    Kramer, Daniel P.

    1996-10-22

    A method for manufacturing low-temperature hermetically sealed optical fi components is provided. The method comprises the steps of: inserting an optical fiber into a housing, the optical fiber having a glass core, a glass cladding and a protective buffer layer disposed around the core and cladding; heating the housing to a predetermined temperature, the predetermined temperature being below a melting point for the protective buffer layer and above a melting point of a solder; placing the solder in communication with the heated housing to allow the solder to form an eutectic and thereby fill a gap between the interior of the housing and the optical fiber; and cooling the housing to allow the solder to form a hermetic compression seal between the housing and the optical fiber.

  2. Low-temperature hermetic sealing of optical fiber components

    DOEpatents

    Kramer, D.P.

    1996-10-22

    A method for manufacturing low-temperature hermetically sealed optical fiber components is provided. The method comprises the steps of: inserting an optical fiber into a housing, the optical fiber having a glass core, a glass cladding and a protective buffer layer disposed around the core and cladding; heating the housing to a predetermined temperature, the predetermined temperature being below a melting point for the protective buffer layer and above a melting point of a solder; placing the solder in communication with the heated housing to allow the solder to form an eutectic and thereby fill a gap between the interior of the housing and the optical fiber; and cooling the housing to allow the solder to form a hermetic compression seal between the housing and the optical fiber. 5 figs.

  3. New hermetic sealing material for vacuum brazing of stainless steels

    NASA Astrophysics Data System (ADS)

    Hildebrandt, S.; Wiehl, G.; Silze, F.

    2016-03-01

    For vacuum brazing applications such as in vacuum interrupter industry Hermetic Sealing Materials (HSM) with low partial pressure are widely used. AgCu28 dominates the hermetic sealing market, as it has a very good wetting behavior on copper and metallized ceramics. Within recent decades wetting on stainless steel has become more and more important. However, today the silver content of HSMs is more in focus than in the past decades, because it has the biggest impact on the material prices. Umicore Technical Materials has developed a new copper based HSM, CuAg40Ga10. The wettability on stainless steel is significantly improved compared to AgCu28 and the total silver content is reduced by almost 44%. In this article the physical properties of the alloy and its brazed joints will be presented compared to AgCu28.

  4. Compressor surge counter

    DOEpatents

    Castleberry, Kimberly N.

    1983-01-01

    A surge counter for a rotating compressor is provided which detects surging by monitoring the vibration signal from an accelerometer mounted on the shaft bearing of the compressor. The circuit detects a rapid increase in the amplitude envelope of the vibration signal, e.g., 4 dB or greater in less than one second, which is associated with a surge onset and increments a counter. The circuit is rendered non-responsive for a period of about 5 seconds following the detection which corresponds to the duration of the surge condition. This prevents multiple registration of counts during the surge period due to rapid swings in vibration amplitude during the period.

  5. Removable, hermetically-sealing, filter attachment system for hostile environments

    DOEpatents

    Mayfield, Glenn L [Richland, WA

    1983-01-01

    A removable and reusable filter attachment system. A filter medium is fixed o, and surrounded by, a filter frame having a coaxial, longitudinally extending, annular rim. The rim engages an annular groove which surrounds the opening of a filter housing. The annular groove contains a fusible material and a heating mechanism for melting the fusible material. Upon resolidifying, the fusible material forms a hermetic bond with the rim and groove. Remelting allows detachment and replacement of the filter frame.

  6. Hermetic Glass-To-Metal Seal For Instrumentation Window

    NASA Technical Reports Server (NTRS)

    Hill, Arthur J.

    1992-01-01

    Proposed mounting scheme for optical element of instrumentation window in pressure vessel ensures truly hermetic seal while minimizing transmission of stress to optical element. Brazed metal seal superior to conventional gaskets of elastomer, carbon, asbestos, or other material compressed between optical element and wall of vessel. Concentric brazed joints in proposed seal bond metal ring to wall of vessel and to optical element. U-shaped cross section allows ring to flex under pressure.

  7. Hermetic Seal Designs for Sample Return Sample Tubes

    NASA Technical Reports Server (NTRS)

    Younse, Paulo J.

    2013-01-01

    Prototypes have been developed of potential hermetic sample sealing techniques for encapsulating samples in a ˜1-cm-diameter thin-walled sample tube that are compatible with IMSAH (Integrated Mars Sample Acquisition and Handling) architecture. Techniques include a heat-activated, finned, shape memory alloy plug; a contracting shape memory alloy activated cap; an expanding shape memory alloy plug; and an expanding torque plug. Initial helium leak testing of the shape memory alloy cap and finned shape memory alloy plug seals showed hermetic- seal capability compared against an industry standard of <1×10-8 atm-cc/s He. These tests were run on both clean tubes and dirty tubes dipped in MMS (Mojave Mars Simulant). The leak tests were also performed after thermal cycling between -135 and +55 ºC to ensure seal integrity after Martian diurnal cycles. Developmental testing is currently being done on the expanding torque plug, and expanding shape memory alloy plug seal designs. The finned shape memory alloy (SMA) plug currently shows hermetic sealing capability based on preliminary tests.

  8. Hermetic aluminum radio frequency interconnection and method for making

    DOEpatents

    Kilgo, Riley D.; Kovacic, Larry; Brow, Richard K.

    2000-01-01

    The present invention provides a light-weight, hermetic coaxial radio-frequency (RF) interconnection having an electrically conductive outer housing made of aluminum or an aluminum alloy, a central electrical conductor made of ferrous or non-ferrous material, and a cylinder of dielectric material comprising a low-melting-temperature, high-thermal-expansion aluminophosphate glass composition for hermetically sealing between the aluminum-alloy outer housing and the ferrous or non-ferrous center conductor. The entire RF interconnection assembly is made permanently hermetic by thermally fusing the center conductor, glass, and housing concurrently by bringing the glass to the melt point by way of exposure to an atmospheric temperature sufficient to melt the glass, less than 540.degree. C., but that does not melt the center conductor or the outer aluminum or aluminum alloy housing. The composition of the glass used is controlled to provide a suitable low dielectric constant so that an appropriate electrical characteristic impedance, for example 50 ohms, can be achieved for an electrical interconnection that performs well at high radio frequencies and also provides an interconnection maintaining a relatively small physical size.

  9. Hermetic aluminum radio frequency interconnection and method for making

    SciTech Connect

    Kilgo, R.D.; Kovacic, L.; Brow, R.K.

    2000-03-14

    The present invention provides a light-weight, hermetic coaxial radio-frequency (RF) interconnection having an electrically conductive outer housing made of aluminum or an aluminum alloy, a central electrical conductor made of ferrous or non-ferrous material, and a cylinder of dielectric material comprising a low-melting-temperature, high-thermal-expansion aluminophosphate glass composition for hermetically sealing between the aluminum-alloy outer housing and the ferrous or non-ferrous center conductor. The entire RF interconnection assembly is made permanently hermetic by thermally fusing the center conductor, glass, and housing concurrently by bringing the glass to the melt point by way of exposure to an atmospheric temperature sufficient to melt the glass, less than 540 C, but that does not melt the center conductor or the outer aluminum or aluminum alloy housing. The composition of the glass used is controlled to provide a suitable low dielectric constant so that an appropriate electrical characteristic impedance, for example 50 ohms, can be achieved for an electrical interconnection that performs well at high radio frequencies and also provides an interconnection maintaining a relatively small physical size.

  10. Kenaf Bast Fibers—Part I: Hermetical Alkali Digestion

    DOE PAGES

    Shi, Jinshu; Shi, Sheldon Q.; Barnes, H. Michael; Horstemeyer, Mark; Wang, Jinwu; Hassan, El-Barbary M.

    2011-01-01

    The objective of this study was to develop a hermetical alkali digestion process to obtain single cellulosic fibers from kenaf bast. Kenaf bast were hermetically digested into single fiber using a 5% sodium hydroxide solution for one hour at four different temperatures (80 ° C, 110 ° C, 130 ° C, and 160 ° C). The hermetical digestion process used in this study produced fibers with high cellulose content (84.2–92.3%) due to the removal of lignin and hemicelluloses. The surface hardness and elastic modulus of the fibers digested at 130 ° C and 160 ° C were improved significantlymore » compared with those digested at 80 ° C. The tensile modulus and tensile strength of the individual fibers reduced as the digestion temperature increased from 110 ° C to 160 ° C. Micropores were generated in fiber cell wall when the fibers were digested at 130 ° C and 160 ° C. The studies on the composites that were made from polypropylene reinforced with the digested fibers indicated that the compatibility between the digested fibers and polypropylene matrix was poor.« less

  11. Transonic compressor technology advancements

    NASA Technical Reports Server (NTRS)

    Benser, W. A.

    1974-01-01

    The highlights of the NASA program on transonic compressors are presented. Effects of blade shape and throat area on losses and flow range are discussed. Some effects of casing treatment on stall margin are presented. Results of tests with varying solidity are also presented. High Mach number, highly loaded stators are discussed and some results of stator hub slit suction are presented.

  12. Reciprocity in directed networks

    NASA Astrophysics Data System (ADS)

    Yin, Mei; Zhu, Lingjiong

    2016-04-01

    Reciprocity is an important characteristic of directed networks and has been widely used in the modeling of World Wide Web, email, social, and other complex networks. In this paper, we take a statistical physics point of view and study the limiting entropy and free energy densities from the microcanonical ensemble, the canonical ensemble, and the grand canonical ensemble whose sufficient statistics are given by edge and reciprocal densities. The sparse case is also studied for the grand canonical ensemble. Extensions to more general reciprocal models including reciprocal triangle and star densities will likewise be discussed.

  13. 23. Station Compressor Room 1 with Air Compressors and Accumulator ...

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

    23. Station Compressor Room 1 with Air Compressors and Accumulator Tanks, view to the south. One of the two large station air compressor units used for depressing the draft tube water level is visible atop a concrete pedestal on the left side of photograph (the second identical compressor is located in an adjacent room). Two of the six station air accumulator tanks are visible in the background. The smaller station service air compressor is visible in right foreground of the photograph was installed in the early 1980s, and replaced the original station service air compressor. - Washington Water Power Clark Fork River Noxon Rapids Hydroelectric Development, Powerhouse, South bank of Clark Fork River at Noxon Rapids, Noxon, Sanders County, MT

  14. Reciprocating Linear Electric Motor

    NASA Technical Reports Server (NTRS)

    Goldowsky, M. P.

    1984-01-01

    Features include structural simplicity and good force/displacement characteristics. Reciprocating motor has simple, rugged construction, relatively low reciprocating weight, improved power delivery, and improved force control. Wear reduced by use of magnetic bearings. Intended to provide drivers for long-lived Stirling-cycle cryogenic refrigerators, concept has less exotic applications, such as fuel pumps.

  15. The Structure of Reciprocity

    ERIC Educational Resources Information Center

    Molm, Linda D.

    2010-01-01

    Reciprocity is one of the defining features of social exchange and social life, yet exchange theorists have tended to take it for granted. Drawing on work from a decade-long theoretical research program, I argue that reciprocity is structured and variable across different forms of exchange, that these variations in the structure of reciprocity…

  16. Reciprocity and uncertainty.

    PubMed

    Bereby-Meyer, Yoella

    2012-02-01

    Guala points to a discrepancy between strong negative reciprocity observed in the lab and the way cooperation is sustained "in the wild." This commentary suggests that in lab experiments, strong negative reciprocity is limited when uncertainty exists regarding the players' actions and the intentions. Thus, costly punishment is indeed a limited mechanism for sustaining cooperation in an uncertain environment.

  17. The Value of Reciprocity

    ERIC Educational Resources Information Center

    Molm, Linda D.; Schaefer, David R.; Collett, Jessica L.

    2007-01-01

    The value of reciprocity in social exchange potentially comprises both instrumental value (the value of the actual benefits received from exchange) and communicative or symbolic value (the expressive and uncertainty reduction value conveyed by features of the act of reciprocity itself). While all forms of exchange provide instrumental value, we…

  18. Reciprocal NUT spacetimes

    NASA Astrophysics Data System (ADS)

    Momeni, Davood; Chattopadhyay, Surajit; Myrzakulov, Ratbay

    2015-05-01

    In this paper, we study the Ehlers' transformation (sometimes called gravitational duality rotation) for reciprocal static metrics. First, we introduce the concept of reciprocal metric. We prove a theorem which shows how we can construct a certain new static solution of Einstein field equations using a seed metric. Later, we investigate the family of stationary spacetimes of such reciprocal metrics. The key here is a theorem from Ehlers', which relates any static vacuum solution to a unique stationary metric. The stationary metric has a magnetic charge. The spacetime represents Newman-Unti-Tamburino (NUT) solutions. Since any stationary spacetime can be decomposed into a 1 + 3 time-space decomposition, Einstein field equations for any stationary spacetime can be written in the form of Maxwell's equations for gravitoelectromagnetic fields. Further, we show that this set of equations is invariant under reciprocal transformations. An additional point is that the NUT charge changes the sign. As an instructive example, by starting from the reciprocal Schwarzschild as a spherically symmetric solution and reciprocal Morgan-Morgan disk model as seed metrics we find their corresponding stationary spacetimes. Starting from any static seed metric, performing the reciprocal transformation and by applying an additional Ehlers' transformation we obtain a family of NUT spaces with negative NUT factor (reciprocal NUT factors).

  19. Reciprocity and uncertainty.

    PubMed

    Bereby-Meyer, Yoella

    2012-02-01

    Guala points to a discrepancy between strong negative reciprocity observed in the lab and the way cooperation is sustained "in the wild." This commentary suggests that in lab experiments, strong negative reciprocity is limited when uncertainty exists regarding the players' actions and the intentions. Thus, costly punishment is indeed a limited mechanism for sustaining cooperation in an uncertain environment. PMID:22289307

  20. Method of Matching Performance of Compressor Systems with that of Aircraft Power Sections

    NASA Technical Reports Server (NTRS)

    Bullock, Robert O.; Keetch, Robert C.; Moses, Jason J.

    1945-01-01

    A method is developed of easily determining the performance of a compressor system relative to that of the power section for a given altitude. Because compressors, reciprocating engines, and turbines are essentially flow devices, the performance of each of these power-plant components is presented in terms of similar dimensionless ratios. The pressure and temperature changes resulting from restrictions of the charge-air flow and from heat transfer in the ducts connecting the components of the power plant are also expressed by the same dimensionless ratios and the losses are included in the performance of the compressor. The performance of a mechanically driven, single-stage compressor in relation to the performance of a conventional air-cooled engine operating at sea-level conditions is presented as an example of the application of the method.

  1. Passive Wireless Hermetic Environment Monitoring System for Spray Painting Workshop.

    PubMed

    Wang, Lifeng; Ma, Jingjing; Huang, Yan; Tang, Dan; Huang, Qing-An

    2016-08-01

    Passive wireless sensors have the advantages of operating without a power supply and remote sensing capability. Hence, they are very suitable for some harsh environments, such as hermetic environments, rotating parts, or very high temperature environments. The spray painting workshop is such a harsh environment, containing a large amount of flammable paint mist and organic gas. Aiming at this special environment of spray painting workshop, a passive wireless hermetic environment monitoring system was designed, fabricated, and demonstrated. The proposed system is composed of a transponder and a reader, and the circuit design of each part is given in detail in this paper. The power and the data transmission between the transponder and the reader are realized by the inductive coupling mechanism. Utilizing the back scatter modulation and channel multiplexing, the frequency signals generated by three different environmental sensors-together with their interfaces in the transponder-are wirelessly read out by the reader. Because of the harsh environment of the spray painting room, the package of the monitoring system is quite important. Three different kinds of filter films for the system package were compared. The experimental results show that the composite filter film aluminum anodic oxide/polytetrafluoroethylene (AAO/PTFE) has the best performance. After fabrication, the measured temperature, humidity, and pressure sensitivities were measured and found to be 180 Hz/°C in the range of 0~60 °C, 100 Hz/%RH in the range of 15~95 %RH, and 42 Hz/hPa in the range of 600~1100 hPa, respectively. Additionally, the remote sensing distance of the monitoring system reaches 4 cm. Finally, the passive wireless hermetic environment monitoring system was installed on the glass wall of the spray painting workshop and was successfully demonstrated.

  2. Passive Wireless Hermetic Environment Monitoring System for Spray Painting Workshop

    PubMed Central

    Wang, Lifeng; Ma, Jingjing; Huang, Yan; Tang, Dan; Huang, Qing-An

    2016-01-01

    Passive wireless sensors have the advantages of operating without a power supply and remote sensing capability. Hence, they are very suitable for some harsh environments, such as hermetic environments, rotating parts, or very high temperature environments. The spray painting workshop is such a harsh environment, containing a large amount of flammable paint mist and organic gas. Aiming at this special environment of spray painting workshop, a passive wireless hermetic environment monitoring system was designed, fabricated, and demonstrated. The proposed system is composed of a transponder and a reader, and the circuit design of each part is given in detail in this paper. The power and the data transmission between the transponder and the reader are realized by the inductive coupling mechanism. Utilizing the back scatter modulation and channel multiplexing, the frequency signals generated by three different environmental sensors—together with their interfaces in the transponder—are wirelessly read out by the reader. Because of the harsh environment of the spray painting room, the package of the monitoring system is quite important. Three different kinds of filter films for the system package were compared. The experimental results show that the composite filter film aluminum anodic oxide/polytetrafluoroethylene (AAO/PTFE) has the best performance. After fabrication, the measured temperature, humidity, and pressure sensitivities were measured and found to be 180 Hz/°C in the range of 0~60 °C, 100 Hz/%RH in the range of 15~95 %RH, and 42 Hz/hPa in the range of 600~1100 hPa, respectively. Additionally, the remote sensing distance of the monitoring system reaches 4 cm. Finally, the passive wireless hermetic environment monitoring system was installed on the glass wall of the spray painting workshop and was successfully demonstrated. PMID:27490546

  3. Passive Wireless Hermetic Environment Monitoring System for Spray Painting Workshop.

    PubMed

    Wang, Lifeng; Ma, Jingjing; Huang, Yan; Tang, Dan; Huang, Qing-An

    2016-01-01

    Passive wireless sensors have the advantages of operating without a power supply and remote sensing capability. Hence, they are very suitable for some harsh environments, such as hermetic environments, rotating parts, or very high temperature environments. The spray painting workshop is such a harsh environment, containing a large amount of flammable paint mist and organic gas. Aiming at this special environment of spray painting workshop, a passive wireless hermetic environment monitoring system was designed, fabricated, and demonstrated. The proposed system is composed of a transponder and a reader, and the circuit design of each part is given in detail in this paper. The power and the data transmission between the transponder and the reader are realized by the inductive coupling mechanism. Utilizing the back scatter modulation and channel multiplexing, the frequency signals generated by three different environmental sensors-together with their interfaces in the transponder-are wirelessly read out by the reader. Because of the harsh environment of the spray painting room, the package of the monitoring system is quite important. Three different kinds of filter films for the system package were compared. The experimental results show that the composite filter film aluminum anodic oxide/polytetrafluoroethylene (AAO/PTFE) has the best performance. After fabrication, the measured temperature, humidity, and pressure sensitivities were measured and found to be 180 Hz/°C in the range of 0~60 °C, 100 Hz/%RH in the range of 15~95 %RH, and 42 Hz/hPa in the range of 600~1100 hPa, respectively. Additionally, the remote sensing distance of the monitoring system reaches 4 cm. Finally, the passive wireless hermetic environment monitoring system was installed on the glass wall of the spray painting workshop and was successfully demonstrated. PMID:27490546

  4. Temperature Swing Adsorption Compressor Development

    NASA Technical Reports Server (NTRS)

    Finn, John E.; Mulloth, Lila M.; Affleck, Dave L.

    2001-01-01

    Closing the oxygen loop in an air revitalization system based on four-bed molecular sieve and Sabatier reactor technology requires a vacuum pump-compressor that can take the low-pressure CO, from the 4BMS and compress and store for use by a Sabatier reactor. NASA Ames Research Center proposed a solid-state temperature-swing adsorption (TSA) compressor that appears to meet performance requirements, be quiet and reliable, and consume less power than a comparable mechanical compressor/accumulator combination. Under this task, TSA compressor technology is being advanced through development of a complete prototype system. A liquid-cooled TSA compressor has been partially tested, and the rest of the system is being fabricated. An air-cooled TSA compressor is also being designed.

  5. Light intensity compressor

    DOEpatents

    Rushford, Michael C.

    1990-01-01

    In a system for recording images having vastly differing light intensities over the face of the image, a light intensity compressor is provided that utilizes the properties of twisted nematic liquid crystals to compress the image intensity. A photoconductor or photodiode material that is responsive to the wavelength of radiation being recorded is placed adjacent a layer of twisted nematic liquid crystal material. An electric potential applied to a pair of electrodes that are disposed outside of the liquid crystal/photoconductor arrangement to provide an electric field in the vicinity of the liquid crystal material. The electrodes are substantially transparent to the form of radiation being recorded. A pair of crossed polarizers are provided on opposite sides of the liquid crystal. The front polarizer linearly polarizes the light, while the back polarizer cooperates with the front polarizer and the liquid crystal material to compress the intensity of a viewed scene. Light incident upon the intensity compressor activates the photoconductor in proportion to the intensity of the light, thereby varying the field applied to the liquid crystal. The increased field causes the liquid crystal to have less of a twisting effect on the incident linearly polarized light, which will cause an increased percentage of the light to be absorbed by the back polarizer. The intensity of an image may be compressed by forming an image on the light intensity compressor.

  6. Light intensity compressor

    DOEpatents

    Rushford, Michael C.

    1990-02-06

    In a system for recording images having vastly differing light intensities over the face of the image, a light intensity compressor is provided that utilizes the properties of twisted nematic liquid crystals to compress the image intensity. A photoconductor or photodiode material that is responsive to the wavelength of radiation being recorded is placed adjacent a layer of twisted nematic liquid crystal material. An electric potential applied to a pair of electrodes that are disposed outside of the liquid crystal/photoconductor arrangement to provide an electric field in the vicinity of the liquid crystal material. The electrodes are substantially transparent to the form of radiation being recorded. A pair of crossed polarizers are provided on opposite sides of the liquid crystal. The front polarizer linearly polarizes the light, while the back polarizer cooperates with the front polarizer and the liquid crystal material to compress the intensity of a viewed scene. Light incident upon the intensity compressor activates the photoconductor in proportion to the intensity of the light, thereby varying the field applied to the liquid crystal. The increased field causes the liquid crystal to have less of a twisting effect on the incident linearly polarized light, which will cause an increased percentage of the light to be absorbed by the back polarizer. The intensity of an image may be compressed by forming an image on the light intensity compressor.

  7. Small Displacement, Long Life On-Orbit Compressor Design and Fabrication

    NASA Technical Reports Server (NTRS)

    Gerlach, C. R.; Schroeder, E. C.; Deffenbaugh, D. D.; Masetta, J. P.

    1989-01-01

    The focus is the generation of technology and fabrication of prototype hardware applicable to seven Space Station compressor system applications. The compressors are of the single acting reciprocating piston type and, in general, may be termed miniature in size compared with normal commercially available equipment. The initial technology development is focused on improved valve designs, and the control of pulsations and heating effects in order to increase compressor efficiency and reduce cycle temperatures, thus permitting significantly increased stage pressure ratios. The initial test compressor was successfully operated at pressure ratios of up to 50:1, and this significant extension of allowable pressure ratio will result in a reduction of the number of required stages and, hence, total hardware thereby reducing system weight and volume. These experiments have also identified the need to employ low shaft speeds, on the order of 250 to 500 rpm, to enhance heat transfer and increase life. The prototype compressor currently being designed, is to be driven by a low-speed brushless dc motor sealed in a case common to the compressor drive mechanism case. The compressor and motor case will communicate with stage suction pressure so that any minor gas leakage past the piston rings will be returned to the suction. Emphasis in this prototype design is being placed on simplicity, durability, commonality of components, and high efficiency.

  8. Hermetically sealed baits for subterranean termites (Isoptera: Rhinotermitidae).

    PubMed

    Su, Nan-Yao

    2007-04-01

    Cellulose baits containing 0.5% hexaflumuron were hermetically sealed in a closed cell polyethylene sheet envelope and placed in soil to test their durability and efficacy against field colonies of the Formosan subterranean termite, Coptotermes formosanus Shiraki, or the eastern subterranean termite, Reticulitermes flavipes (Kollar). The closed cell polyethylene sheet was readily tunneled through by termites, yet it was impervious to water and protected the cellulose baits and hexaflumuron from the environment. Only in a few incidents did the polyethylene envelope become infiltrated by plant roots, resulting in water intrusion and apparent degradation of cellulose baits. After consuming one to three sealed baits, three colonies each of both termite species were eliminated. The sealed baits may be placed in soil for months or years without the need of monitoring, and they are readily penetrated and fed upon by termites when they are present. Application of baits hermetically sealed in a protective sheet may save labor costs by bypassing the monitoring phase, circumvent the station avoidance by some termite species, and enable the use of baiting technologies in large areas such as agricultural fields in which the manual monitoring is impractical.

  9. A Hermetic Wireless Subretinal Neurostimulator for Vision Prostheses

    PubMed Central

    Shire, Douglas B.; Chen, Jinghua; Doyle, Patrick; Gingerich, Marcus D.; Cogan, Stuart F.; Drohan, William A.; Behan, Sonny; Theogarajan, Luke; Wyatt, John L.; Rizzo, Joseph F.

    2016-01-01

    A miniaturized, hermetically encased, wirelessly operated retinal prosthesis has been developed for preclinical studies in the Yucatan minipig, and includes several design improvements over our previously reported device. The prosthesis attaches conformally to the outside of the eye and electrically drives a microfabricated thin-film polyimide array of sputtered iridium oxide film electrodes. This array is implanted into the subretinal space using a customized ab externo surgical technique. The implanted device includes a hermetic titanium case containing a 15-channel stimulator chip and discrete circuit components. Feedthroughs in the case connect the stimulator chip to secondary power and data receiving coils on the eye and to the electrode array under the retina. Long-term in vitro pulse testing of the electrodes projected a lifetime consistent with typical devices in industry. The final assembly was tested in vitro to verify wireless operation of the system in physiological saline using a custom RF transmitter and primary coils. Stimulation pulse strength, duration, and frequency were programmed wirelessly from a Peripheral Component Interconnect eXtensions for Instrumentation (PXI) computer. Operation of the retinal implant has been verified in two pigs for up to five and a half months by detecting stimulus artifacts generated by the implanted device. PMID:21859595

  10. Hermetic SiC-SiC composite tubes

    SciTech Connect

    Kowbel, W.; Liu, Y.; Bruce, C.; Withers, J.C.; Kolaya, L.E.; Lewis, N.

    1998-12-31

    SiC-SiC composites have good potential for structural applications but are limited by expensive forming techniques. A high purity {beta}-SiC fiber produced by MER, and a polymer derived SiC matrix were used to fabricate small diameter hermetic SiC-SiC tubes. The process was optimized to prevent the formation of a brittle structure while rapidly forming a dense matrix. This tube was made hermetic by first coating the surface of the tube with a silicon carbide particle filled polymer slurry, followed by a Chemical Vapor Infiltration/Deposition (CVI/CVD) SiC deposition which was performed to close any residual porosity on the composite tube surface. X-ray diffraction and Transmission Electron Microscopy (TEM) examination was performed to determine the fiber and matrix structures. These tubes were found to be impermeable to helium with leak rates below 10{sup {minus}9} cc/sec as determined by testing similar to MIL-STD-883D, method 1014.10. This high level of impermeability was sustained following thermal cycling between room temperature and 1,520 C.

  11. 21 CFR 500.23 - Thermally processed low-acid foods packaged in hermetically sealed containers.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Thermally processed low-acid foods packaged in hermetically sealed containers. 500.23 Section 500.23 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT... Administrative Rulings and Decisions § 500.23 Thermally processed low-acid foods packaged in hermetically...

  12. General view of low pressure compressor (unit #3) with compressor ...

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

    General view of low pressure compressor (unit #3) with compressor in foreground and engines in background. High pressure stage is on left, low pressure stage is on right. - Burnsville Natural Gas Pumping Station, Saratoga Avenue between Little Kanawha River & C&O Railroad line, Burnsville, Braxton County, WV

  13. VIEW OF COMPRESSOR ROOM AT GROUND LEVEL SHOWING COMPRESSOR EQUIPMENT. ...

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

    VIEW OF COMPRESSOR ROOM AT GROUND LEVEL SHOWING COMPRESSOR EQUIPMENT. VIEW FACING SOUTH - U.S. Naval Base, Pearl Harbor, Ford Island Polaris Missile Lab & U.S. Fleet Ballistic Missile Submarine Training Center, Between Lexington Boulvevard and the sea plane ramps on the southwest side of Ford Island, Pearl City, Honolulu County, HI

  14. Rapid evaluation of hermetic seals using digital shearography

    NASA Astrophysics Data System (ADS)

    Hung, Y. Y.; Shi, Dahuan

    1995-06-01

    Packages such as microelectronic packages require hermetic seals, as the reliability of such devices is extremely important. One possible failure is due to leakage resulting from imperfect hermetical seals in microchips and microelectronic packages. Imperfect sealing may allow moisture and other impurities to migrate into the packages and cause the devices to malfunction. Current methods of testing hermetics are very slow and cumbersome and thus they cannot be used for mass inspection in production. This paper presents a novel technique based on digital shearography, which allows hermetic seals to be rapidly tested. This method employs a technique of digital shearography for measuring time-dependent deformation. In this paper, a figure is shown of the technique whereby the object to be studied is illuminated with a point source of coherent light and it is imaged by an image-shearing video camera which produces a pair of laterally sheared images on the image sensor of the camera. In other words, two object points are brought to meet in the image plane; they interfere producing a speckle pattern. When the object is deformed, a phase change is induced in the speckle pattern which measures the relative displacement between the interfering points. In the study of a time-dependent deformation of a test object, the speckle patterns received by the image- shearing video camera are continuously digitized at a predetermined rate depending on the deformation rate via a frame grabber into a micro-computer such as a PC, and stored in the memory of the computer. After recording, the displacement derivative versus time for any point of interest can be extracted by plotting the phase change of the speckle pattern at the point versus time from the computer memory. The total phase change can be obtained by integrating the phase curve. The evaluation of hermetic seals in microelectronic packages is based on measuring the time-deformation of the package's lid. The package to be tested

  15. Hidden patterns of reciprocity.

    PubMed

    Syi

    2014-03-21

    Reciprocity can help the evolution of cooperation. To model both types of reciprocity, we need the concept of strategy. In the case of direct reciprocity there are four second-order action rules (Simple Tit-for-tat, Contrite Tit-for-tat, Pavlov, and Grim Trigger), which are able to promote cooperation. In the case of indirect reciprocity the key component of cooperation is the assessment rule. There are, again, four elementary second-order assessment rules (Image Scoring, Simple Standing, Stern Judging, and Shunning). The eight concepts can be formalized in an ontologically thin way we need only an action predicate and a value function, two agent concepts, and the constant of goodness. The formalism helps us to discover that the action and assessment rules can be paired, and that they show the same patterns. The logic of these patterns can be interpreted with the concept of punishment that has an inherent paradoxical nature.

  16. Hidden patterns of reciprocity.

    PubMed

    Syi

    2014-03-21

    Reciprocity can help the evolution of cooperation. To model both types of reciprocity, we need the concept of strategy. In the case of direct reciprocity there are four second-order action rules (Simple Tit-for-tat, Contrite Tit-for-tat, Pavlov, and Grim Trigger), which are able to promote cooperation. In the case of indirect reciprocity the key component of cooperation is the assessment rule. There are, again, four elementary second-order assessment rules (Image Scoring, Simple Standing, Stern Judging, and Shunning). The eight concepts can be formalized in an ontologically thin way we need only an action predicate and a value function, two agent concepts, and the constant of goodness. The formalism helps us to discover that the action and assessment rules can be paired, and that they show the same patterns. The logic of these patterns can be interpreted with the concept of punishment that has an inherent paradoxical nature. PMID:24368125

  17. OMC Compressor Case

    NASA Technical Reports Server (NTRS)

    Humphrey, W. Donald

    1997-01-01

    This report summarizes efforts expended in the development of an all-composite compressor case. Two pre-production units have been built, one utilizing V-CAP and one utilizing AFR-700B resin systems. Both units have been rig tested at elevated temperatures well above design limit loads. This report discusses the manufacturing processes, test results, and Finite Element Analysis performed. The V-CAP unit was funded by NASA-Lewis Research Center in 1994 under contract number NAS3- 27442 for Development of an All-Composite OMC Compressor Case. This contract was followed by an Air Force study in 1996 to build and identical unit using the AFR-700B resin system in place of the V-CAP system. The second compressor case was funded under U.S. Air Force contract F33615-93-D-5326, Advanced Materials for Aerospace Structures Special Studies (AMAS3), Delivery Order 0021 entitled "Advanced Polymeric Composite Materials and Structures Technology for Advanced High Temperature Gas Turbine Engines.' Initial studies using the V-CAP resin system were undertaken in 1993 under a NASA Lewis contract (NAS3-26829). A first prototype unit was developed in a joint program between Textron-Lycoming (now Allied Signal) and Brunswick (now Lincoln Composites). This unit included composite end closures using low density, high temperature molded end closures. The units was similar in size and shape to a titanium case currently used on the PT-21 0 engine and was funded as part of the integrated High Performance Turbine Engine Technology (EHPTET) initiative of DOD and NASA.

  18. QRFXFreeze: Queryable Compressor for RFX

    PubMed Central

    Senthilkumar, Radha; Nandagopal, Gomathi; Ronald, Daphne

    2015-01-01

    The verbose nature of XML has been mulled over again and again and many compression techniques for XML data have been excogitated over the years. Some of the techniques incorporate support for querying the XML database in its compressed format while others have to be decompressed before they can be queried. XML compression in which querying is directly supported instantaneously with no compromise over time is forced to compromise over space. In this paper, we propose the compressor, QRFXFreeze, which not only reduces the space of storage but also supports efficient querying. The compressor does this without decompressing the compressed XML file. The compressor supports all kinds of XML documents along with insert, update, and delete operations. The forte of QRFXFreeze is that the textual data are semantically compressed and are indexed to reduce the querying time. Experimental results show that the proposed compressor performs much better than other well-known compressors. PMID:26065027

  19. QRFXFreeze: Queryable Compressor for RFX.

    PubMed

    Senthilkumar, Radha; Nandagopal, Gomathi; Ronald, Daphne

    2015-01-01

    The verbose nature of XML has been mulled over again and again and many compression techniques for XML data have been excogitated over the years. Some of the techniques incorporate support for querying the XML database in its compressed format while others have to be decompressed before they can be queried. XML compression in which querying is directly supported instantaneously with no compromise over time is forced to compromise over space. In this paper, we propose the compressor, QRFXFreeze, which not only reduces the space of storage but also supports efficient querying. The compressor does this without decompressing the compressed XML file. The compressor supports all kinds of XML documents along with insert, update, and delete operations. The forte of QRFXFreeze is that the textual data are semantically compressed and are indexed to reduce the querying time. Experimental results show that the proposed compressor performs much better than other well-known compressors. PMID:26065027

  20. Practical experience with unstable compressors

    NASA Technical Reports Server (NTRS)

    Malanoski, S. B.

    1980-01-01

    Using analytical mathematical modeling techniques for the system components, an attempt is made to gauge the destabilizing effects in a number of compressor designs. In particular the overhung (or cantilevered) compressor designs and the straddle-mounted (or simply supported) compressor designs are examined. Recommendations are made, based on experiences with stable and unstable compressors, which can be used as guides in future designs. High and low pressure compressors which operate well above their fundamental rotor-bearing lateral natural frequencies can suffer from destructive subsynchronous vibration. Usually the elements in the system design which contribute to this vibration, other than the shafting and the bearings, are the seals (both gas labyrinth and oil breakdown bushings) and the aerodynamic components.

  1. Device for tensioning test specimens within an hermetically sealed chamber

    NASA Technical Reports Server (NTRS)

    Evans, P. K.; Shady, D. L. (Inventor)

    1977-01-01

    The device is characterized by a support column adapted to be received within an insulated, hermetically sealable chamber. A plurality of anchor pins are mounted on the column for releasibly connecting thereto a plurality of test specimens. A plurality of axially displaceable pull rods are received by the column in coaxial alignment with the anchor pins. One end of each pull rod is provided with a coupling for connecting the pull rod to a test specimen. The opposite end of the pull rod is entended through a cover plate and adapted to be connected with a remotely related linear actuator through a connecting link including a load cell for measuring stress as the pull rod is placed in tension by the actuator.

  2. Hermetic fiber optic-to-metal connection technique

    DOEpatents

    Kramer, Daniel P.

    1992-09-01

    A glass-to-glass hermetic sealing technique is disclosed which can be used to splice lengths of glass fibers together. A solid glass preform is inserted into the cavity of a metal component which is then heated to melt the glass. An end of an optical fiber is then advanced into the molten glass and the entire structure cooled to solidify the glass in sealing engagement with the optical fiber end and the metal cavity. The surface of the re-solidified glass may be machined for mating engagement with another component to make a spliced fiber optic connection. The resultant structure has a helium leak rate of less than 1.times.10.sup.-8 cm.sup.3 /sec.

  3. Improvement program for polycarbonate capacitors. [hermetically sealed, and ac wound

    NASA Technical Reports Server (NTRS)

    Bailey, R. R.; Waterman, K. D.

    1973-01-01

    Hermetically sealed, wound, AC, polycarbonate capacitors incorporating design improvements recommended in a previous study were designed and built. A 5000 hour, 400 Hz ac life test was conducted using 384 of these capacitors to verify the adequacy of the design improvements. The improvements incorporated in the capacitors designed for this program eliminated the major cause of failure found in the preceding work, termination failure. A failure cause not present in the previous test became significant in this test with capacitors built from one lot of polycarbonate film. The samples from this lot accounted for 25 percent of the total test complement. Analyses of failed samples showed that the film had an excessive solvent content. This solvent problem was found in 37 of the total 46 failures which occurred in this test. The other nine were random failures resulting from causes such as seal leaks, foreign particles, and possibly wrinkles.

  4. Method of fabricating high-density hermetic electrical feedthroughs

    DOEpatents

    Shah, Kedar G.; Pannu, Satinderpall S.; Delima, Terri L.

    2015-06-02

    A method of fabricating electrical feedthroughs selectively removes substrate material from a first side of an electrically conductive substrate (e.g. a bio-compatible metal) to form an array of electrically conductive posts in a substrate cavity. An electrically insulating material (e.g. a bio-compatible sealing glass) is then flowed to fill the substrate cavity and surround each post, and solidified. The solidified insulating material is then exposed from an opposite second side of the substrate so that each post is electrically isolated from each other as well as the bulk substrate. In this manner a hermetic electrically conductive feedthrough construction is formed having an array of electrical feedthroughs extending between the first and second sides of the substrate from which it was formed.

  5. Method of making an integral window hermetic fiber optic component

    DOEpatents

    Dalton, R.D.; Kramer, D.P.; Massey, R.T.; Waker, D.A.

    1996-11-12

    In the fabrication of igniters, actuators, detonators, and other pyrotechnic devices to be activated by a laser beam, an integral optical glass window is formed by placing a preform in the structural member of the device and then melting the glass and sealing it in place by heating at a temperature between the ceramming temperature of the glass and the melting point of the metal, followed by rapid furnace cooling to avoid devitrification. No other sealing material is needed to achieve hermeticity. A preferred embodiment of this type of device is fabricated by allowing the molten glass to flow further and form a plano-convex lens integral with and at the bottom of the window. The lens functions to decrease the beam divergence caused by refraction of the laser light passing through the window when the device is fired by means of a laser beam. 9 figs.

  6. Method of making an integral window hermetic fiber optic component

    DOEpatents

    Dalton, Rick D.; Kramer, Daniel P.; Massey, Richard T.; Waker, Damon A.

    1996-11-12

    In the fabrication of igniters, actuators, detonators, and other pyrotechnic devices to be activated by a laser beam, an integral optical glass window is formed by placing a preform in the structural member of the device and then melting the glass and sealing it in place by heating at a temperature between the ceramming temperature of the glass and the melting point of the metal, followed by rapid furnace cooling to avoid devitrification. No other sealing material is needed to achieve hermeticity. A preferred embodiment of this type of device is fabricated by allowing the molten glass to flow further and form a plano-convex lens integral with and at the bottom of the window. The lens functions to decrease the beam divergence caused by refraction of the laser light passing through the window when the device is fired by means of a laser beam.

  7. Aerodynamic Design of Axial Flow Compressors

    NASA Technical Reports Server (NTRS)

    Bullock, R. O. (Editor); Johnsen, I. A.

    1965-01-01

    An overview of 'Aerodynamic systems design of axial flow compressors' is presented. Numerous chapters cover topics such as compressor design, ptotential and viscous flow in two dimensional cascades, compressor stall and blade vibration, and compressor flow theory. Theoretical aspects of flow are also covered.

  8. Centrifugal Compressor Aeroelastic Analysis Code

    NASA Astrophysics Data System (ADS)

    Keith, Theo G., Jr.; Srivastava, Rakesh

    2002-01-01

    Centrifugal compressors are very widely used in the turbomachine industry where low mass flow rates are required. Gas turbine engines for tanks, rotorcraft and small jets rely extensively on centrifugal compressors for rugged and compact design. These compressors experience problems related with unsteadiness of flowfields, such as stall flutter, separation at the trailing edge over diffuser guide vanes, tip vortex unsteadiness, etc., leading to rotating stall and surge. Considerable interest exists in small gas turbine engine manufacturers to understand and eventually eliminate the problems related to centrifugal compressors. The geometric complexity of centrifugal compressor blades and the twisting of the blade passages makes the linear methods inapplicable. Advanced computational fluid dynamics (CFD) methods are needed for accurate unsteady aerodynamic and aeroelastic analysis of centrifugal compressors. Most of the current day industrial turbomachines and small aircraft engines are designed with a centrifugal compressor. With such a large customer base and NASA Glenn Research Center being, the lead center for turbomachines, it is important that adequate emphasis be placed on this area as well. Currently, this activity is not supported under any project at NASA Glenn.

  9. Hermetic Narratives and False Analysis: A Unique Variant of the Mechanism of Identification With the Aggressor.

    PubMed

    Amir, Dana

    2016-08-01

    This paper focuses on a unique variant of the mechanism of identification with the aggressor. The term "hermetic narrative" refers to a condition in which the trauma victim creates a hermetically sealed narrative of witnessing, which becomes an addictive and subjugating object in itself, while obstructing natural processes of thinking. This paper examines the ways in which the hermetic narrative reconstructs victim-aggressor relations both within the individual and in the analytic relationship. It further discusses the risk of creating a "false analysis" that is based on a malignant cooperation of the analyst and patient with the internalized traumatic object. PMID:27500704

  10. Gated compressor, distortionless signal limiter

    NASA Technical Reports Server (NTRS)

    Woodbury, R. C. (Inventor)

    1974-01-01

    A distortionless gated compressor for limiting the amplitude of a signal so as not to produce undesired signal levels responsive thereto is disclosed. The gated compressor includes a distortionless multiplier which multiplies an AC signal from a factor defined by a DC control signal. The compressor includes a plurality of channels each responsive to a signal produced in response to the multiplier's output. When the signal supplied to any channel exceeds a prescribed level, the level of the DC control signal is reduced to reduce the multiplier's output level and thereby prevent the signal applied to any channel from exceeding its prescribed level.

  11. Magentically actuated compressor

    NASA Technical Reports Server (NTRS)

    Evans, J.; Studer, P. A. (Inventor)

    1985-01-01

    A vibration free fluid compressor particularly adapted for Stirling cycle cryogenic refrigeration apparatus comprises a pair of identical opposing ferromagnetic pistons located in a housing and between a gas spring including a sealed volume of a working fluid such as gas under pressure. The gas compresses and expands in accordance with movement of the pistons to generate a compression wave which can be vented to other apparatus, for example, a displacer unit in a Stirling cycle engine. The pistons are urged outwardly due to the pressure of the gas; however, a fixed electromagnetic coil assembly located in the housing adjacent the pistons, is periodically energized to produce a magnetic field which interlinks the pistons in such a fashion that the pistons are mutually attracted to one another. The mass of the pistons, in conjunction with the compressed gas between them, form a naturally resonant system which, when the pistons are electromagnetically energized, produces an oscillating compression wave in the entrapped fluid medium.

  12. Free piston inertia compressor

    DOEpatents

    Richards, W.D.C.; Bilodeau, D.; Marusak, T.; Dutram, L. Jr.; Brady, J.

    A free piston inertia compressor comprises a piston assembly including a connecting rod having pistons on both ends, the cylinder being split into two substantially identical portions by a seal through which the connecting rod passes. Vents in the cylinder wall are provided near the seal to permit gas to escape the cylinder until the piston covers the vent whereupon the remaining gas in the cylinder functions as a gas spring and cushions the piston against impact on the seal. The connecting rod has a central portion of relatively small diameter providing free play of the connecting rod through the seal and end portions of relatively large diameter providing a limited tolerance between the connecting rod and the seal. Finally, the seal comprises a seal ring assembly consisting of a dampener plate, a free floating seal at the center of the dampener plate and a seal retainer plate in one face of the dampener plate.

  13. Free piston inertia compressor

    DOEpatents

    Richards, William D. C.; Bilodeau, Denis; Marusak, Thomas; Dutram, Jr., Leonard; Brady, Joseph

    1981-01-01

    A free piston inertia compressor comprises a piston assembly including a connecting rod having pistons on both ends, the cylinder being split into two substantially identical portions by a seal through which the connecting rod passes. Vents in the cylinder wall are provided near the seal to permit gas to excape the cylinder until the piston covers the vent whereupon the remaining gas in the cylinder functions as a gas spring and cushions the piston against impact on the seal. The connecting rod has a central portion of relatively small diameter providing free play of the connecting rod through the seal and end portions of relatively large diameter providing a limited tolerance between the connecting rod and the seal. Finally, the seal comprises a seal ring assembly consisting of a dampener plate, a free floating seal at the center of the dampener plate and a seal retainer plate in one face of the dampener plate.

  14. On the characteristics of centrifugal-reciprocating machines. [cryogenic coolers

    NASA Technical Reports Server (NTRS)

    Higa, W. H.

    1980-01-01

    A method of compressing helium gas for cryogenic coolers is presented which uses centrifugal force to reduce the forces on the connecting rod and crankshaft in the usual reciprocating compressor. This is achieved by rotating the piston-cylinder assembly at a speed sufficient for the centrifugal force on the piston to overcome the compressional force due to the working fluid. The rotating assembly is dynamically braked in order to recharge the working space with fluid. The intake stroke consists of decelerating the rotating piston-cylinder assembly and the exhaust stroke consists of accelerating the assembly.

  15. Fairchild 7A compressor model

    SciTech Connect

    Foster, R.E.

    1986-09-23

    The Fairchild 7A centrifugal compressor used in the X-326 isotopic ''top'' cascade at the Portsmouth Gaseous Diffusion Plant has been modeled using a proprietary computer code called COMPAL by Concepts E.T.I., Inc. of Norwich, VT. The 7A compressor is described and the results of the modeling calculations are presented. Performance characteristics curves (PR vs. flow) are included for various mixtures of UF/sub 6/ and N/sub 2/ gases.

  16. Series of Reciprocal Triangular Numbers

    ERIC Educational Resources Information Center

    Bruckman, Paul; Dence, Joseph B.; Dence, Thomas P.; Young, Justin

    2013-01-01

    Reciprocal triangular numbers have appeared in series since the very first infinite series were summed. Here we attack a number of subseries of the reciprocal triangular numbers by methodically expressing them as integrals.

  17. Reciprocal Predicates in Japanese.

    ERIC Educational Resources Information Center

    Ishii, Yasuo

    A study of reciprocals in Japanese compares two kinds: (1) a verbal suffix "aw"; and (2) an NP argument "otagai." Although "otagai" appears to be taken care of by syntactic binding theory, it is proposed that there is no evidence for the existence of a syntactic position of the object NP in the case of "aw." The suffix can be characterized as…

  18. Effects of Humidity on Non-Hermetically Packaged III-V Structures and Devices

    NASA Technical Reports Server (NTRS)

    Leon, R.; Martin, S.; Lee, T.; Okuno, J.; Ruiz, R.; Gauldin, R.; Gaidis, M.; Smith, R.

    1999-01-01

    High humidity and temperature test (known as 85/85 tests) were performed on various III-V devices and structures to determine environmental effects in non-hermetically packaged GaAs membrane mixer diodes.

  19. Compressor bleed cooling fluid feed system

    DOEpatents

    Donahoo, Eric E; Ross, Christopher W

    2014-11-25

    A compressor bleed cooling fluid feed system for a turbine engine for directing cooling fluids from a compressor to a turbine airfoil cooling system to supply cooling fluids to one or more airfoils of a rotor assembly is disclosed. The compressor bleed cooling fluid feed system may enable cooling fluids to be exhausted from a compressor exhaust plenum through a downstream compressor bleed collection chamber and into the turbine airfoil cooling system. As such, the suction created in the compressor exhaust plenum mitigates boundary layer growth along the inner surface while providing flow of cooling fluids to the turbine airfoils.

  20. Glass-ceramic hermetic seals to high thermal expansion metals

    DOEpatents

    Kramer, D.P.; Massey, R.T.

    1987-04-28

    A process for forming glass-ceramic materials from an alkaline silica-lithia glass composition comprising 60-72 mole-% SiO/sub 2/, 18-27 mole-% Li/sub 2/O, 0-5 mole-% Al/sub 2/O/sub 3/, 0-6 mole-% K/sub 2/O, 0-3 mole-% B/sub 2/O/sub 3/, and 0.5-2.5 mole-% P/sub 2/O/sub 5/, which comprises heating said glass composition at a first temperature within the 950-1050/degree/C range for 5-60 minutes, and then at a devitrification temperature within the 700-900/degree/C range for about 5-300 minutes to obtain a glass-ceramic having a thermal expansion coefficient of up to 210 x 10/sup /minus/7///degree/C. These ceramics form strong, hermetic seals with high expansion metals such as stainless steel alloys. An intermediate nucleation heating step conducted at a temperature within the range of 675-750/degree/C for 10-120 minutes may be employed between the first stage and the devitrification stage. 1 fig., 2 tabs.

  1. NEA Multi-Chamber Sample Return Container with Hermetic Sealing

    NASA Technical Reports Server (NTRS)

    Rafeek, Shaheed; Kong, Kin Yuen; Sadick, Shazad; Porter, Christopher C.

    2000-01-01

    A sample return container is being developed by Honeybee Robotics to receive samples from a derivative of the Champollion/ST4 Sample Acquisition and Transfer Mechanism or other samplers such as the 'Touch and Go' Surface Sampler (TGSS), and then hermetically seal the samples for a sample return mission. The container is enclosed in a phase change material (PCM) chamber to prevent phase change during return and re-entry to earth. This container is designed to operate passively with no motors and actuators. Using the rotation axis of the TGSS sampler for interfacing, transferring and sealing samples, the container consumes no electrical power and therefore minimizes sample temperature change. The circular container houses multiple isolated canisters, which will be sealed individually for samples acquired from different sites or depths. The TGSS based sampler indexes each canister to the sample transfer position, below the index interface for sample transfer. After sample transfer is completed, the sampler indexes a seal carrier, which lines up seals with the openings of the canisters. The sampler moves to the sealing interface and seals the sample canisters one by one. The sealing interface can be designed to work with C-seals, knife edge seals and cup seals. This sample return container is being developed by Honeybee Robotics in collaboration with the JPL Exploration Technology program. A breadboard system of the sample return container has been recently completed and tested. Additional information is contained in the original extended abstract.

  2. Robust hermetic packaging techniques for MEMS integrated microsystems.

    SciTech Connect

    Chae, Junseok; Stark, Brian H.; Kuo, Andrew; Oliver, Andrew David; Najafi, Khalil

    2005-03-01

    This work is the result of a Sandia National Laboratories LDRD funded fellowship at the University of Michigan. Although, guidance and suggestions were offered by Sandia, the work contained here is primarily the work of Brian H. Stark, and his advisor, Professor Khalil Najafi. Junseok Chae, Andrew Kuo, and their coworkers at the University of Michigan helped to record some of the data. The following is an abstract of their work. We have developed a vacuum packaging technology using a thick nickel film to seal MEMS structures at the wafer level. The package is fabricated in a three-mask process by electroplating a 40 micro-meter thick nickel film over an 8 micro-meter sacrificial photoresist that is removed prior to package sealing. Implementation of electrical feedthroughs in this process requires no planarization. The large release channel enables an 800x800 micro-meter package to be released in less than three hours. Several mechanisms, based upon localized melting and lead/tin solder bumping, for sealing the release channel have been investigated. We have also developed Pirani gauges, integrated with this package, which can be used to establish the hermeticity of the different sealing technologies. They have measured a sealing pressure of approximately 1.5 Torr. Our work differs from previous Pirani gauges in that we utilize a novel doubly anchored structure that stiffens the structural membrane while not substantially degrading performance in order to measure fine leak rates.

  3. Electrochemical Hydrogen Compressor

    SciTech Connect

    David P. Bloomfield; Brian S. MacKenzie

    2006-05-01

    The Electrochemical Hydrogen Compressor EHC was evaluated against DOE applications for compressing hydrogen at automobile filling stations, in future hydrogen pipelines and as a commercial replacement for conventional diaphragm hydrogen compressors. It was also evaluated as a modular replacement for the compressors used in petrochemical refineries. If the EHC can be made inexpensive, reliable and long lived then it can satisfy all these applications save pipelines where the requirements for platinum catalyst exceeds the annual world production. The research performed did not completely investigate Molybdenum as a hydrogen anode or cathode, it did show that photoetched 316 stainless steel is inadequate for an EHC. It also showed that: molybdenum bipolar plates, photochemical etching processes, and Gortex Teflon seals are too costly for a commercial EHC. The use of carbon paper in combination with a perforated thin metal electrode demonstrated adequate anode support strength, but is suspect in promoting galvanic corrosion. The nature of the corrosion mechanisms are not well understood, but locally high potentials within the unit cell package are probably involved. The program produced a design with an extraordinary high cell pitch, and a very low part count. This is one of the promising aspects of the redesigned EHC. The development and successful demonstration of the hydraulic cathode is also important. The problem of corrosion resistant metal bipolar plates is vital to the development of an inexpensive, commercial PEM fuel cell. Our research suggests that there is more to the corrosion process in fuel cells and electrochemical compressors than simple, steady state, galvanic stability. It is an important area for scientific investigation. The experiments and analysis conducted lead to several recommended future research directions. First, we need a better understanding of the corrosion mechanisms involved. The diagnosis of experimental cells with titration to

  4. Reciprocity relations in aerodynamics

    NASA Technical Reports Server (NTRS)

    Heaslet, Max A; Spreiter, John R

    1953-01-01

    Reverse flow theorems in aerodynamics are shown to be based on the same general concepts involved in many reciprocity theorems in the physical sciences. Reciprocal theorems for both steady and unsteady motion are found as a logical consequence of this approach. No restrictions on wing plan form or flight Mach number are made beyond those required in linearized compressible-flow analysis. A number of examples are listed, including general integral theorems for lifting, rolling, and pitching wings and for wings in nonuniform downwash fields. Correspondence is also established between the buildup of circulation with time of a wing starting impulsively from rest and the buildup of lift of the same wing moving in the reverse direction into a sharp-edged gust.

  5. Contractor safety training reciprocity

    SciTech Connect

    Melancon, R.

    1996-08-01

    In June, 1995, the National Petroleum Refiners Association (NPRA) adhoc committee on Contractor Safety Training, turned over the task of developing reciprocity agreements with all Contractor Safety Training Councils to the Executive Directors of each of the Council`s. The Council representatives were to develop these agreements based on the NPRA adhoc committee training objectives that were developed jointly by representatives of the petroleum industry, chemical industry, contractors and the Council`s.

  6. Water injected fuel cell system compressor

    DOEpatents

    Siepierski, James S.; Moore, Barbara S.; Hoch, Martin Monroe

    2001-01-01

    A fuel cell system including a dry compressor for pressurizing air supplied to the cathode side of the fuel cell. An injector sprays a controlled amount of water on to the compressor's rotor(s) to improve the energy efficiency of the compressor. The amount of water sprayed out the rotor(s) is controlled relative to the mass flow rate of air inputted to the compressor.

  7. New coatings extend compressor service life

    SciTech Connect

    Chow, R.; McMordie, B.; Wiegand, R.

    1995-10-01

    To lengthen production runs, a Canadian ethylene operator experimented with a coating system to protect a critical compressor`s rotor from hydrocarbon-polymerization/fouling. In ethylene manufacturing, compressor fouling is an accepted ``fact of life.`` Past attempts to minimize fouling in the crack-gas compression train were unsuccessful or marginally cost-effective. Applying protective coatings to a critical-service ethylene compressor rotor slowed oiling, thus lengthening the production run time by one year.

  8. Multi-stage hydride-hydrogen compressor

    NASA Astrophysics Data System (ADS)

    Golben, P. M.

    A 4-stage metal hydride/hydrogen compressor that uses low temperature hot water (75 C) as its energy source has been built and tested. The compressor utilizes a new hydride heat exchanger technique that has achieved fast cycling time (with 20 C cooling water) on the order of 1 min. This refinement substantially decreases the size, weight and cost of the unit when compared to previous hydride compressors or even conventional mechanical diaphragm compressors.

  9. A High Temperature Hermetic Primer and a Variable Spring Tester

    SciTech Connect

    Begeal, D.R.

    1994-05-01

    Percussion primers are used at Sandia to ignite energetic components such as pyrotechnic actuators and thermal batteries. This report describes a High Temperature Hermetic Primer (HTHP) that was developed to replace a previous G16 Percussion Primer Subassembly (Gl6PPS). The ignition mix in these primers is the same as in the discontinued Remington 44G16 (KC1O{sub 3}, SbS{sub 3}, and Ca{sub 2}Si). The HTHP has nearly the same sensitivity as the 44G16 and a significantly lower sensitivity than the G16PPS. In parallel with the HTHP development, we also designed a Variable Spring Tester (VST) to determine percussion primer ignition sensitivity with firing pins that have the same mass as those used in field applications. The tester is capable of accelerating firing pins over a velocity range of 100 to 600 inches per second for pins weighing up to 6 grams. The desired impulse can be preselected with an accuracy of better than {plus_minus}1%. The actual impulse is measured on every shot. The VST was characterized using the WW42Cl primer, as well as with the G16PPS and the HTHP. Compared to data from conventional ball drop testers, we found that ignition sensitivities were lower and there was less scatter in the sensitivity data. Our experiments indicate that ignition sensitivity is not strictly energy dependent, but also depends on the rate of deposition, or firing pin velocity in this case. Development results for the HTHP and Variable Spring Tester are discussed and design details are shown.

  10. 46 CFR 154.1415 - Air compressor.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 5 2013-10-01 2013-10-01 false Air compressor. 154.1415 Section 154.1415 Shipping COAST... Equipment § 154.1415 Air compressor. Each vessel must have an air compressor to recharge the bottles for the air-breathing apparatus....

  11. 46 CFR 154.1415 - Air compressor.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 5 2012-10-01 2012-10-01 false Air compressor. 154.1415 Section 154.1415 Shipping COAST... Equipment § 154.1415 Air compressor. Each vessel must have an air compressor to recharge the bottles for the air-breathing apparatus....

  12. 46 CFR 154.1415 - Air compressor.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 5 2014-10-01 2014-10-01 false Air compressor. 154.1415 Section 154.1415 Shipping COAST... Equipment § 154.1415 Air compressor. Each vessel must have an air compressor to recharge the bottles for the air-breathing apparatus....

  13. 46 CFR 154.1415 - Air compressor.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 5 2011-10-01 2011-10-01 false Air compressor. 154.1415 Section 154.1415 Shipping COAST... Equipment § 154.1415 Air compressor. Each vessel must have an air compressor to recharge the bottles for the air-breathing apparatus....

  14. 46 CFR 154.1415 - Air compressor.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 5 2010-10-01 2010-10-01 false Air compressor. 154.1415 Section 154.1415 Shipping COAST... Equipment § 154.1415 Air compressor. Each vessel must have an air compressor to recharge the bottles for the air-breathing apparatus....

  15. An ultrafast reciprocating probe

    NASA Astrophysics Data System (ADS)

    Liu, Wenbin; Tan, Yi; Wang, Wenhao; Gao, Zhe

    2016-11-01

    For tokamak plasma diagnostics, an ultrafast reciprocating probe system driven by magnetic field coils, achieving a maximum velocity of 21 m/s, is introduced. The probes are attached with a driving hoop made of carbon steel and accelerated by three acceleration coils in series, then decelerated by two deceleration coils and buffer springs and return slowly. The coils with a current of about 1 kA generate a magnetic field of about 1 T. This probe system has been tested on the SUNIST (Sino-UNIted Spherical Tokamak) spherical tokamak. Radial profiles of the floating potential and other plasma parameters measured by this probe system are given.

  16. High pressure reciprocating pump

    SciTech Connect

    Besic, D.

    1990-05-01

    This patent describes an improvement in a reciprocating pump having a plunger and a pumping chamber. It comprises: the plunger having a bore communicating with an intersection opening and wherein the plunger incudes a central axis; a suction valve and a discharge valve, each having an axis of actuation parallel to a central axis of the plunger; the suction valve comprising a cylindrical core having a central passageway, and the core is slidably received by a seating member and resiliently biased to the seating member.

  17. Reciprocating magnetic refrigerator

    NASA Technical Reports Server (NTRS)

    Johnson, D. L.

    1985-01-01

    A 4 to 15 K magnetic refrigerator to test as an alternative to the Joule-Thomson circuit as the low temperature stage of a 4 to 300 K closed-cycle refrigerator was developed. The reciprocating magnetic refrigerator consists of two matrices of gadolinium gallium garnet spheres located in tandem on a single piston which alternately moves each matrix into a 7 telsa magnetic field. A separate helium gas circuit is used as the heat exchange mechanism for the low and the high temperature extremes of the magnetic refrigerator. Details of the design and results of the initial refrigerator component tests are presented.

  18. Multiple volume compressor for hot gas engine

    DOEpatents

    Stotts, Robert E.

    1986-01-01

    A multiple volume compressor for use in a hot gas (Stirling) engine having a plurality of different volume chambers arranged to pump down the engine when decreased power is called for and return the working gas to a storage tank or reservoir. A valve actuated bypass loop is placed over each chamber which can be opened to return gas discharged from the chamber back to the inlet thereto. By selectively actuating the bypass valves, a number of different compressor capacities can be attained without changing compressor speed whereby the capacity of the compressor can be matched to the power available from the engine which is used to drive the compressor.

  19. Spectral compressor vibration analysis techniques

    SciTech Connect

    Hanson, M.L.

    1982-02-01

    Studies at GAT have verified that the spectral distribution of energy in gaseous diffusion compressor vibrations contains information pertinent to the state of the compressor's ''health.'' Based on that conclusion, vibration analysis capabilities were included in the CUP computer data acquisition system. In order for that information to be used for diagnosis of incipient failure mechanisms, however, spectral features must be empirically associated with actual malfunctions and validated statistically as diagnostic symptoms. When the system was acquired, indicators were generally unknown except for those associated with unbalance, misalignment, 00 secondary surge and severe resonant blade vibrations. Others must be developed as in-service malfunctions occur. The power spectral density function (PSDF) has historically been used to compute vibration spectra. Accurate, high-resolution power density spectra require long data-acquisition periods which is inconsistent with frequent examinations of all up-rated compressors. Detection of gross spectral changes indicative of a need for detailed analyses has been accomplished at a rate of less than 1 minute per compressor. An optimum analytical sequence will be based on trade offs. Work is in progress to identify additional malfunction indicators and investigate tools other than the PSDF to provide faster diagnoses. 6 figs.

  20. A modeling study of a centrifugal compressor

    SciTech Connect

    Popovic, P.; Shapiro, H.N.

    1998-12-31

    A centrifugal compressor, which is part of a chlorofluorocarbon R-114 chiller installation, was investigated, operating with a new refrigerant, hydrofluorocarbon R-236ea, a proposed alternative to R-114. A large set of R-236ea operating data, as well as a limited amount of R-114 data, were available for this study. A relatively simple analytical compressor model was developed to describe compressor performance. The model was built upon a thorough literature search, experimental data, and some compressor design parameters. Two original empirical relations were developed, providing a new approach to the compressor modeling. The model was developed in a format that would permit it to be easily incorporated into a complete chiller simulation. The model was found to improve somewhat on the quantitative and physical aspects of a compressor model of the same format found in the literature. It was found that the compressor model is specific to the particular refrigerant.

  1. Reciprocal relations in electroacoustics

    SciTech Connect

    Chassagne, C.; Bedeaux, D.

    2014-07-28

    In a colloidal suspension, one can generate sound waves by the application of an alternating electric field (Electrokinetic Sonic Amplitude, i.e., ESA). Another phenomenon is electrophoresis (Electrophoretic Mobility, i.e., EM) where a colloidal particle moves relative to the solvent in an electric field. Vice versa one can generate electric fields or electric currents by sound waves (Colloid Vibration Potential/Current, i.e., CVP/CVI). In 1988 and 1990, O’Brien [J. Fluid Mech. 190, 71–86 (1988) and O’Brien, J. Fluid Mech. 212, 81–93 (1990)] derived a reciprocal relation between the proportionality coefficients of the EM and CVI phenomena. In this paper, we will generalize his proof by constructing the relevant entropy production from which the linear force-flux relations follow. General relations are derived for electrolyte solutions, of which colloidal suspensions are a particular case. The relations between CVI, CVP, EM, and ESA are discussed. O’Brien's reciprocal relation then follows as an Onsager relation. The relation is valid for any applied electric field frequency, particle surface charge and particle concentration (even in the presence of particle-particle interactions) provided the system is isotropic.

  2. Vacuum encapsulated hermetically sealed diamond amplified cathode capsule and method for making same

    DOEpatents

    Rao, Triveni; Walsh, John; Gangone, Elizabeth

    2014-12-30

    A vacuum encapsulated, hermetically sealed cathode capsule for generating an electron beam of secondary electrons, which generally includes a cathode element having a primary emission surface adapted to emit primary electrons, an annular insulating spacer, a diamond window element comprising a diamond material and having a secondary emission surface adapted to emit secondary electrons in response to primary electrons impinging on the diamond window element, a first cold-weld ring disposed between the cathode element and the annular insulating spacer and a second cold-weld ring disposed between the annular insulating spacer and the diamond window element. The cathode capsule is formed by a vacuum cold-weld process such that the first cold-weld ring forms a hermetical seal between the cathode element and the annular insulating spacer and the second cold-weld ring forms a hermetical seal between the annular spacer and the diamond window element whereby a vacuum encapsulated chamber is formed within the capsule.

  3. Pulse compressor with aberration correction

    SciTech Connect

    Mankos, Marian

    2015-11-30

    In this SBIR project, Electron Optica, Inc. (EOI) is developing an electron mirror-based pulse compressor attachment to new and retrofitted dynamic transmission electron microscopes (DTEMs) and ultrafast electron diffraction (UED) cameras for improving the temporal resolution of these instruments from the characteristic range of a few picoseconds to a few nanoseconds and beyond, into the sub-100 femtosecond range. The improvement will enable electron microscopes and diffraction cameras to better resolve the dynamics of reactions in the areas of solid state physics, chemistry, and biology. EOI’s pulse compressor technology utilizes the combination of electron mirror optics and a magnetic beam separator to compress the electron pulse. The design exploits the symmetry inherent in reversing the electron trajectory in the mirror in order to compress the temporally broadened beam. This system also simultaneously corrects the chromatic and spherical aberration of the objective lens for improved spatial resolution. This correction will be found valuable as the source size is reduced with laser-triggered point source emitters. With such emitters, it might be possible to significantly reduce the illuminated area and carry out ultrafast diffraction experiments from small regions of the sample, e.g. from individual grains or nanoparticles. During phase I, EOI drafted a set of candidate pulse compressor architectures and evaluated the trade-offs between temporal resolution and electron bunch size to achieve the optimum design for two particular applications with market potential: increasing the temporal and spatial resolution of UEDs, and increasing the temporal and spatial resolution of DTEMs. Specialized software packages that have been developed by MEBS, Ltd. were used to calculate the electron optical properties of the key pulse compressor components: namely, the magnetic prism, the electron mirror, and the electron lenses. In the final step, these results were folded

  4. Room-temperature wafer scale bonding using smoothed Au seal ring surfaces for hermetic sealing

    NASA Astrophysics Data System (ADS)

    Kurashima, Yuichi; Maeda, Atsuhiko; Takagi, Hideki

    2016-01-01

    We evaluated room-temperature bonding characteristics of electroplated Au surfaces smoothed by the lift-off and imprint methods. As a result, we found that smoothed surfaces enable strong bonding; on the other hand, electroplated rough surfaces result in very weak bonding. In transmission electron microscopy observations, no delamination was observed at the bonding interface bonded at room temperature using a smooth surface prepared by the lift-off method. Moreover, the hermeticity of the bonding interface prepared using smoothed surfaces was evaluated using diaphragm structures. As a result, we confirmed that good hermetic sealing was achieved using the electroplated Au surface smoothed by the lift-off method.

  5. Toward a Behavior of Reciprocity

    PubMed Central

    Gernsbacher, Morton Ann

    2014-01-01

    It is frequently believed that autism is characterized by a lack of social or emotional reciprocity. In this article, I question that assumption by demonstrating how many professionals—researchers and clinicians—and likewise many parents, have neglected the true meaning of reciprocity. Reciprocity is “a relation of mutual dependence or action or influence,” or “a mode of exchange in which transactions take place between individuals who are symmetrically placed.” Assumptions by clinicians and researchers suggest that they have forgotten that reciprocity needs to be mutual and symmetrical—that reciprocity is a two-way street. Research is reviewed to illustrate that when professionals, peers, and parents are taught to act reciprocally, autistic children become more responsive. In one randomized clinical trial of “reciprocity training” to parents, their autistic children's language developed rapidly and their social engagement increased markedly. Other demonstrations of how parents and professionals can increase their behavior of reciprocity are provided. PMID:25598865

  6. Trust, Respect, and Reciprocity

    PubMed Central

    Phong, Tran Viet; Nhan, Le Nguyen Thanh; Dung, Nguyen Thanh; Ngan, Ta Thi Dieu; Kinh, Nguyen Van; Parker, Michael; Bull, Susan

    2015-01-01

    International science funders and publishers are driving a growing trend in data sharing. There is mounting pressure on researchers in low- and middle-income settings to conform to new sharing policies, despite minimal empirically grounded accounts of the ethical challenges of implementing the policies in these settings. This study used in-depth interviews and focus group discussions with 48 stakeholders in Vietnam to explore the experiences, attitudes, and expectations that inform ethical and effective approaches to sharing clinical research data. Distinct views on the role of trust, respect, and reciprocity were among those that emerged to inform culturally appropriate best practices. We conclude by discussing the challenges that authors of data-sharing policies should consider in this unique context. PMID:26297747

  7. Reciprocating linear motor

    NASA Technical Reports Server (NTRS)

    Goldowsky, Michael P. (Inventor)

    1987-01-01

    A reciprocating linear motor is formed with a pair of ring-shaped permanent magnets having opposite radial polarizations, held axially apart by a nonmagnetic yoke, which serves as an axially displaceable armature assembly. A pair of annularly wound coils having axial lengths which differ from the axial lengths of the permanent magnets are serially coupled together in mutual opposition and positioned with an outer cylindrical core in axial symmetry about the armature assembly. One embodiment includes a second pair of annularly wound coils serially coupled together in mutual opposition and an inner cylindrical core positioned in axial symmetry inside the armature radially opposite to the first pair of coils. Application of a potential difference across a serial connection of the two pairs of coils creates a current flow perpendicular to the magnetic field created by the armature magnets, thereby causing limited linear displacement of the magnets relative to the coils.

  8. Reciprocating wind engine

    SciTech Connect

    Van Mechelen, B.

    1980-12-09

    A reciprocating wind engine is described which utilizes plural, movably mounted sets of panels to form pistons. Cooperating first and second pistons may be spaced from each other on either side of a central crankshaft. As the wind strikes the surface of a first set of panels, the first piston is moved toward the crankshaft and the second piston is pulled toward the crankshaft from the opposite side. When both pistons are adjacent the crankshaft, the panels on the first or windward piston open to allow the wind to pass therethrough into contact with the panels of the second piston which are closed to present a uniform surface to the wind. The pistons are forced away from the crankshaft to complete one cycle of operation. The output from the crankshaft may be utilized to generate electricity, or for any other suitable purpose. Plural engine segments may be cooperatively joined together to form a bank of such units.

  9. Ultra-Efficient Engine Technology (UEET), Proof of Concept Compressor, Advanced Compressor Casing T

    NASA Technical Reports Server (NTRS)

    2004-01-01

    Ultra-Efficient Engine Technology (UEET), Proof of Concept Compressor, Advanced Compressor Casing Treatment testing; close up - throttle valve -wide open; oil and air lines plus instrumentation between collector and gearbox.

  10. Magnetic power piston fluid compressor

    NASA Technical Reports Server (NTRS)

    Gasser, Max G. (Inventor)

    1994-01-01

    A compressor with no moving parts in the traditional sense having a housing having an inlet end allowing a low pressure fluid to enter and an outlet end allowing a high pressure fluid to exit is described. Within the compressor housing is at least one compression stage to increase the pressure of the fluid within the housing. The compression stage has a quantity of magnetic powder within the housing, is supported by a screen that allows passage of the fluid, and a coil for selectively providing a magnetic field across the magnetic powder such that when the magnetic field is not present the individual particles of the powder are separated allowing the fluid to flow through the powder and when the magnetic field is present the individual particles of the powder pack together causing the powder mass to expand preventing the fluid from flowing through the powder and causing a pressure pulse to compress the fluid.

  11. Hermetic diamond capsules for biomedical implants enabled by gold active braze alloys.

    PubMed

    Lichter, Samantha G; Escudié, Mathilde C; Stacey, Alastair D; Ganesan, Kumaravelu; Fox, Kate; Ahnood, Arman; Apollo, Nicholas V; Kua, Dunstan C; Lee, Aaron Z; McGowan, Ceara; Saunders, Alexia L; Burns, Owen; Nayagam, David A X; Williams, Richard A; Garrett, David J; Meffin, Hamish; Prawer, Steven

    2015-01-01

    As the field of biomedical implants matures the functionality of implants is rapidly increasing. In the field of neural prostheses this is particularly apparent as researchers strive to build devices that interact with highly complex neural systems such as vision, hearing, touch and movement. A retinal implant, for example, is a highly complex device and the surgery, training and rehabilitation requirements involved in deploying such devices are extensive. Ideally, such devices will be implanted only once and will continue to function effectively for the lifetime of the patient. The first and most pivotal factor that determines device longevity is the encapsulation that separates the sensitive electronics of the device from the biological environment. This paper describes the realisation of a free standing device encapsulation made from diamond, the most impervious, long lasting and biochemically inert material known. A process of laser micro-machining and brazing is described detailing the fabrication of hermetic electrical feedthroughs and laser weldable seams using a 96.4% gold active braze alloy, another material renowned for biochemical longevity. Accelerated ageing of the braze alloy, feedthroughs and hermetic capsules yielded no evidence of corrosion and no loss of hermeticity. Samples of the gold braze implanted for 15 weeks, in vivo, caused minimal histopathological reaction and results were comparable to those obtained from medical grade silicone controls. The work described represents a first account of a free standing, fully functional hermetic diamond encapsulation for biomedical implants, enabled by gold active alloy brazing and laser micro-machining.

  12. Final Report. Conversion of Low Temperature Waste Heat Utilizing Hermetic Organic Rankine Cycle

    SciTech Connect

    Fuller, Robert L.

    2005-04-20

    The design of waste heat recovery using the organic Rankine cycle (ORC) engine is updated. Advances in power electronics with lower cost enable the use of a single shaft, high-speed generator eliminating wear items and allowing hermetic sealing of the working fluid. This allows maintenance free operation and a compact configuration that lowers cost, enabling new market opportunities.

  13. From Secrets to Science: Technical Writing, Utility, and the Hermetic Tradition in Agricola's "De Re Metallica."

    ERIC Educational Resources Information Center

    Longo, Bernadette

    1997-01-01

    Relates that, in the mid-1500s, Agricola combined the traditions of Hermetic secrets and handbooks to compile mining lore into "De Re Metallica," in which he wrote clearly and simply, illustrated information with graphics, and rationalized use of occult knowledge based on utility. States his text paved the way for philosophers to legitimate…

  14. Au-In-based Hermetic Sealing for MEMS Packaging for Down-Hole Application

    NASA Astrophysics Data System (ADS)

    Chidambaram, Vivek; Bangtao, Chen; Lip, Gan Chee; Rhee Min Woo, Daniel

    2014-07-01

    Hermetic sealing of micro-electro mechanical systems (MEMS) sensors for down-hole application requires high-quality void-free bonds, with metallic hermetic sealing being widely used for this purpose. As most of the MEMS sensors cannot withstand high temperatures, transient liquid phase (TLP) bonding is promising for metallic sealing applications, since the re-melting temperature of the bond is much higher than the bonding temperature. In this paper, major issues involving TLP bonding, including non-uniform diffusion kinetics across the interface and the formation of intermetallic compounds prior to bonding for fast reactive metallic systems like Au-In, have been addressed by using diffusion barriers. The performance of various diffusion barriers that include Ti, Ni, and Pt has been evaluated. Ni has been determined to be a prospective candidate, since it averts diffusion to a certain extent prior to TLP bonding. The mechanical strength and hermeticity of the Au-In joints have also been characterized after aging at 300 °C up to 500 h. No major changes in the thermo-mechanical properties of the AuIn and AuIn2 phases were observed and, hence, these phases are concluded to be thermally stable at this temperature regime. Improvements in hermeticity were confirmed when subjected to high-temperature thermal aging.

  15. HIGH-DENSITY, BIO-COMPATIBLE, AND HERMETIC ELECTRICAL FEEDTHROUGHS USING EXTRUDED METAL VIAS

    SciTech Connect

    Shah, K G; Delima, T; Felix, S; Sheth, H; Tolosa, V; Tooker, A; Pannu, S S

    2012-03-28

    Implanted medical devices such as pacemakers and neural prosthetics require that the electronic components that power these devices are protected from the harsh chemical and biological environment of the body. Typically, the electronics are hermetically sealed inside a bio-compatible package containing feedthroughs that transmit electrical signals, while being impermeable to particles or moisture. We present a novel approach for fabricating one of the highest densities of biocompatible hermetic feedthroughs in alumina (Al{sub 2}O{sub 3}). Alumina substrates with laser machined vias of 200 {micro}m pitch were conformally metallized and lithographically patterned. Hermetic electrical feedthroughs were formed by extruding metal stud-bumps partially through the vias. Hermeticity testing showed leak rates better than 9 x 10{sup -10} torr-l/s. Based on our preliminary results and process optimization, this extruded metal via approach is a high-density, low temperature, cost-effective, and robust method of miniaturizing electrical feedthroughs for a wide range of implantable bio-medical device applications.

  16. HIGH-DENSITY, BIO-COMPATIBLE, AND HERMETIC ELECTRICAL FEEDTHROUGHS USING EXTRUDED METAL VIAS

    SciTech Connect

    Tooker, A; Shah, K; Tolosa, V; Sheth, H; Felix, S; Delima, T; Pannu, S

    2012-03-29

    Implanted medical devices such as pacemakers and neural prosthetics require that the electronic components that power these devices are protected from the harsh chemical and biological environment of the body. Typically, the electronics are hermetically sealed inside a bio-compatible package containing feedthroughs that transmit electrical signals, while being impermeable to particles or moisture. We present a novel approach for fabricating one of the highest densities of biocompatible hermetic feedthroughs in alumina (Al{sub 2}O{sub 3}). Alumina substrates with laser machined vias of 200 {mu}m pitch were conformally metallized and lithographically patterned. Hermetic electrical feedthroughs were formed by extruding metal studbumps partially through the vias. Hermeticity testing showed leak rates better than 9x10{sup -10} torr-l/s. Based on our preliminary results and process optimization, this extruded metal via approach is a high-density, low temperature, cost-effective, and robust method of miniaturizing electrical feedthroughs for a wide range of implantable bio-medical device applications.

  17. Hermetic diamond capsules for biomedical implants enabled by gold active braze alloys.

    PubMed

    Lichter, Samantha G; Escudié, Mathilde C; Stacey, Alastair D; Ganesan, Kumaravelu; Fox, Kate; Ahnood, Arman; Apollo, Nicholas V; Kua, Dunstan C; Lee, Aaron Z; McGowan, Ceara; Saunders, Alexia L; Burns, Owen; Nayagam, David A X; Williams, Richard A; Garrett, David J; Meffin, Hamish; Prawer, Steven

    2015-01-01

    As the field of biomedical implants matures the functionality of implants is rapidly increasing. In the field of neural prostheses this is particularly apparent as researchers strive to build devices that interact with highly complex neural systems such as vision, hearing, touch and movement. A retinal implant, for example, is a highly complex device and the surgery, training and rehabilitation requirements involved in deploying such devices are extensive. Ideally, such devices will be implanted only once and will continue to function effectively for the lifetime of the patient. The first and most pivotal factor that determines device longevity is the encapsulation that separates the sensitive electronics of the device from the biological environment. This paper describes the realisation of a free standing device encapsulation made from diamond, the most impervious, long lasting and biochemically inert material known. A process of laser micro-machining and brazing is described detailing the fabrication of hermetic electrical feedthroughs and laser weldable seams using a 96.4% gold active braze alloy, another material renowned for biochemical longevity. Accelerated ageing of the braze alloy, feedthroughs and hermetic capsules yielded no evidence of corrosion and no loss of hermeticity. Samples of the gold braze implanted for 15 weeks, in vivo, caused minimal histopathological reaction and results were comparable to those obtained from medical grade silicone controls. The work described represents a first account of a free standing, fully functional hermetic diamond encapsulation for biomedical implants, enabled by gold active alloy brazing and laser micro-machining. PMID:25890743

  18. A new hermetic antenna for wireless transmission systems of implantable medical devices.

    PubMed

    Marcelli, E; Scalambra, F; Cercenelli, L; Plicchi, G

    2007-01-01

    In implantable medical devices (IMDs), the need of telemetry systems able to provide wireless bidirectional communication to interrogate and remotely program the device, as well as to monitor the physiological status of the patient, is growing. The object of the present study was to evaluate a new hermetic antenna for wireless short-range transmission system for IMDs which would assure reliable long-term functioning due to the high level of hermeticity of antenna's housing that limits the influence of body tissue environment on transmitted signals. Experimental tests were conducted on three different prototypes to evaluate the most efficient antenna configuration for transmission both in the air and through a mixture simulating the human thorax. Further tests were performed to assess the influence of electro-catheters connected to IMDs on transmitted signals. Results showed that the hermetic antenna guarantees a good wireless transmission both in the air and through the human thorax simulator. The results also show that the presence of an electro-catheter can influence the effective radiated power (ERP) transmitted depending on its position in relation to the telemetric circuitry. Both a controlled increase of the ERP without exceeding the limits imposed by rules and the optimization of the tuning between the antenna and the transmitter can assure a reliable short-range transmission (several meters) using the new hermetic antenna proposed. PMID:16504564

  19. Algorithm for Controlling a Centrifugal Compressor

    NASA Technical Reports Server (NTRS)

    Benedict, Scott M.

    2004-01-01

    An algorithm has been developed for controlling a centrifugal compressor that serves as the prime mover in a heatpump system. Experimental studies have shown that the operating conditions for maximum compressor efficiency are close to the boundary beyond which surge occurs. Compressor surge is a destructive condition in which there are instantaneous reversals of flow associated with a high outlet-to-inlet pressure differential. For a given cooling load, the algorithm sets the compressor speed at the lowest possible value while adjusting the inlet guide vane angle and diffuser vane angle to maximize efficiency, subject to an overriding requirement to prevent surge. The onset of surge is detected via the onset of oscillations of the electric current supplied to the compressor motor, associated with surge-induced oscillations of the torque exerted by and on the compressor rotor. The algorithm can be implemented in any of several computer languages.

  20. SCREW COMPRESSOR CHARACTERISTICS FOR HELIUM REFRIGERATION SYSTEMS

    SciTech Connect

    Ganni, Venkatarao; Knudsen, Peter; Creel, Jonathan; Arenius, Dana; Casagrande, Fabio; Howell, Matt

    2008-03-01

    The oil injected screw compressors have practically replaced all other types of compressors in modern helium refrigeration systems due to their large displacement capacity, minimal vibration, reliability and capability of handling helium's high heat of compression.At the present state of compressor system designs for helium systems, typically two-thirds of the lost input power is due to the compression system. Therefore it is important to understand the isothermal and volumetric efficiencies of these machines to help properly design these compression systems to match the refrigeration process. This presentation summarizes separate tests that have been conducted on Sullair compressors at the Superconducting Super-Collider Laboratory (SSCL) in 1993, Howden compressors at Jefferson Lab (JLab) in 2006 and Howden compressors at the Spallation Neutron Source (SNS) in 2006. This work is part of an ongoing study at JLab to understand the theoretical basis for these efficiencies and their loss

  1. Upstream reciprocity in heterogeneous networks.

    PubMed

    Iwagami, Akio; Masuda, Naoki

    2010-08-01

    Many mechanisms for the emergence and maintenance of altruistic behavior in social dilemma situations have been proposed. Indirect reciprocity is one such mechanism, where other-regarding actions of a player are eventually rewarded by other players with whom the original player has not interacted. The upstream reciprocity (also called generalized indirect reciprocity) is a type of indirect reciprocity and represents the concept that those helped by somebody will help other unspecified players. In spite of the evidence for the enhancement of helping behavior by upstream reciprocity in rats and humans, theoretical support for this mechanism is not strong. In the present study, we numerically investigate upstream reciprocity in heterogeneous contact networks, in which the players generally have different number of neighbors. We show that heterogeneous networks considerably enhance cooperation in a game of upstream reciprocity. In heterogeneous networks, the most generous strategy, by which a player helps a neighbor on being helped and in addition initiates helping behavior, first occupies hubs in a network and then disseminates to other players. The scenario to achieve enhanced altruism resembles that seen in the case of the Prisoner's Dilemma game in heterogeneous networks.

  2. Healthy reciprocity in sexual interaction.

    PubMed

    Heino, J; Ojanlatva, A

    2000-02-01

    The purpose of the article is to discuss reciprocity in sexual interaction within a couple relationship in which heterosexual orientation is assumed and satisfaction considered. Reciprocity is modelled as an exchange of services which at its best functions as an unwritten contract, a mutual understanding regarding fairness of returned services, and a desire to comply with this principle together with a loved one/lover. An equal treatment of and balanced attitudes towards one another are present together with a just distribution of benefits and concessions or compromises. Reciprocity involves a relative term although healthy reciprocity can be defined for discussion and assessed as a degree of mutual satisfaction. Sexual interaction issues, skills to obtain satisfaction, and sexual and emotional compatibility are important elements in reciprocity. Understandable communication is an essential contributor in the implementation of reciprocity. Conflict-making dialogue should generally be avoided and connotive meanings of words taken into account. Erotophilia-erotophobia dimensions influence both the learning about and attitudes towards sexuality and contribute to personal and professional abilities to assess sexual problems and to attend to them. Erotic touch is a minimum requirement of love making. Sexual orientation, sexual desire, and intimacy influence sexual compatibility. Equity and exchange models are discussed, and a reciprocity model is proposed.

  3. MTR COMPRESSOR BUILDING, TRA651. TWO JOY COMPRESSORS ARE INSTALLED. OUT ...

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

    MTR COMPRESSOR BUILDING, TRA-651. TWO JOY COMPRESSORS ARE INSTALLED. OUT OF VIEW ON RIGHT WERE TWO INGERSOLL-RAND COMPRESSORS. NOTE FRAME STRUCTURE OF METAL-SIDING BUILDING. COMPARE WITH ID-33-G-4. INL NEGATIVE NO. 56-1257. Jack L. Anderson, Photographer, 4/20/1956 - Idaho National Engineering Laboratory, Test Reactor Area, Materials & Engineering Test Reactors, Scoville, Butte County, ID

  4. Thermal modelling and analysis of an oil-free linear compressor

    NASA Astrophysics Data System (ADS)

    Oliveira, M. J.; Diniz, M. C.; Deschamps, C. J.

    2015-08-01

    Gas superheating in the suction system may significantly reduce the volumetric and isentropic efficiencies of small reciprocating compressors adopted for household refrigeration. This paper reports a thermal modelling approach developed to predict superheating in an oil- free linear compressor. A simulation code based on the finite volume method was adopted to solve heat conduction in the solid components and gas flow inside the compressor shell. In order to reduce the computational cost, the compression cycle inside the cylinder was modelled with a transient lumped formulation, but in a coupled manner with the remainder of the solution domain. Comparisons between numerical and experimental results of temperature showed discrepancies in some solid components and in the gas path along the discharge system. However, the model was able to predict suction gas superheating in good agreement with measurements. A sensitivity analysis of the temperature distribution with respect to two design parameters was also carried out. The model is particularly useful for compressor design since no experimental calibration is required.

  5. 40 CFR 264.1053 - Standards: Compressors.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... (CONTINUED) STANDARDS FOR OWNERS AND OPERATORS OF HAZARDOUS WASTE TREATMENT, STORAGE, AND DISPOSAL FACILITIES Air Emission Standards for Equipment Leaks § 264.1053 Standards: Compressors. (a) Each...

  6. 40 CFR 264.1053 - Standards: Compressors.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... (CONTINUED) STANDARDS FOR OWNERS AND OPERATORS OF HAZARDOUS WASTE TREATMENT, STORAGE, AND DISPOSAL FACILITIES Air Emission Standards for Equipment Leaks § 264.1053 Standards: Compressors. (a) Each...

  7. 40 CFR 264.1053 - Standards: Compressors.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... (CONTINUED) STANDARDS FOR OWNERS AND OPERATORS OF HAZARDOUS WASTE TREATMENT, STORAGE, AND DISPOSAL FACILITIES Air Emission Standards for Equipment Leaks § 264.1053 Standards: Compressors. (a) Each...

  8. 40 CFR 264.1053 - Standards: Compressors.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... (CONTINUED) STANDARDS FOR OWNERS AND OPERATORS OF HAZARDOUS WASTE TREATMENT, STORAGE, AND DISPOSAL FACILITIES Air Emission Standards for Equipment Leaks § 264.1053 Standards: Compressors. (a) Each...

  9. Improved heat switch for gas sorption compressor

    NASA Technical Reports Server (NTRS)

    Chan, C. K.

    1985-01-01

    Thermal conductivities of the charcoal bed and the copper matrix for the gas adsorption compressor were measured by the concentric-cylinder method. The presence of the copper matrix in the charcoal bed enhanced the bed conductance by at least an order of magnitude. Thermal capacities of the adsorbent cell and the heat leaks to two compressor designs were measured by the transient method. The new gas adsorption compressor had a heat switch that could transfer eight times more heat than the previous one. The cycle time for the new prototype compressor is also improved by a factor of eight to within the minute range.

  10. Simulation of centrifugal compressor transient performance for process plant applications

    SciTech Connect

    MacDougal, I.; Elder, R.L.

    1983-01-01

    The development of a theoretical model capable of simulating centrifugal compressor transient performance (including compressor surge) is detailed. Simulation results from a Fortran computer program are compared with measured compressor transient data. Good simulation of compressor transients between stable operating points, and compressor presurge flow oscillations has been obtained. General application criteria are presented for the geometric distribution of model elements within a compressor system. Model applications and future work are outlined.

  11. Direct reciprocity in spatial populations enhances R-reciprocity as well as ST-reciprocity.

    PubMed

    Miyaji, Kohei; Tanimoto, Jun; Wang, Zhen; Hagishima, Aya; Ikegaya, Naoki

    2013-01-01

    As is well-known, spatial reciprocity plays an important role in facilitating the emergence of cooperative traits, and the effect of direct reciprocity is also obvious for explaining the cooperation dynamics. However, how the combination of these two scenarios influences cooperation is still unclear. In the present work, we study the evolution of cooperation in 2 × 2 games via considering both spatial structured populations and direct reciprocity driven by the strategy with 1-memory length. Our results show that cooperation can be significantly facilitated on the whole parameter plane. For prisoner's dilemma game, cooperation dominates the system even at strong dilemma, where maximal social payoff is still realized. In this sense, R-reciprocity forms and it is robust to the extremely strong dilemma. Interestingly, when turning to chicken game, we find that ST-reciprocity is also guaranteed, through which social average payoff and cooperation is greatly enhanced. This reciprocity mechanism is supported by mean-field analysis and different interaction topologies. Thus, our study indicates that direct reciprocity in structured populations can be regarded as a more powerful factor for the sustainability of cooperation.

  12. Direct reciprocity in spatial populations enhances R-reciprocity as well as ST-reciprocity.

    PubMed

    Miyaji, Kohei; Tanimoto, Jun; Wang, Zhen; Hagishima, Aya; Ikegaya, Naoki

    2013-01-01

    As is well-known, spatial reciprocity plays an important role in facilitating the emergence of cooperative traits, and the effect of direct reciprocity is also obvious for explaining the cooperation dynamics. However, how the combination of these two scenarios influences cooperation is still unclear. In the present work, we study the evolution of cooperation in 2 × 2 games via considering both spatial structured populations and direct reciprocity driven by the strategy with 1-memory length. Our results show that cooperation can be significantly facilitated on the whole parameter plane. For prisoner's dilemma game, cooperation dominates the system even at strong dilemma, where maximal social payoff is still realized. In this sense, R-reciprocity forms and it is robust to the extremely strong dilemma. Interestingly, when turning to chicken game, we find that ST-reciprocity is also guaranteed, through which social average payoff and cooperation is greatly enhanced. This reciprocity mechanism is supported by mean-field analysis and different interaction topologies. Thus, our study indicates that direct reciprocity in structured populations can be regarded as a more powerful factor for the sustainability of cooperation. PMID:23951272

  13. Social evolution: reciprocity there is.

    PubMed

    Taborsky, Michael

    2013-06-01

    The theory of cooperation predicts that altruism can be established by reciprocity, yet empirical evidence from nature is contentious. Increasingly though, experimental results from social vertebrates challenge the nearly exclusive explanatory power of relatedness for the evolution of cooperation.

  14. Group formation through indirect reciprocity

    NASA Astrophysics Data System (ADS)

    Oishi, Koji; Shimada, Takashi; Ito, Nobuyasu

    2013-03-01

    The emergence of group structure of cooperative relations is studied in an agent-based model. It is proved that specific types of reciprocity norms lead individuals to split into two groups only inside of which they are cooperative. The condition for the evolutionary stability of the norms is also obtained. This result suggests reciprocity norms, which usually promote cooperation, can cause society's separation into multiple groups.

  15. Moral assessment in indirect reciprocity.

    PubMed

    Sigmund, Karl

    2012-04-21

    Indirect reciprocity is one of the mechanisms for cooperation, and seems to be of particular interest for the evolution of human societies. A large part is based on assessing reputations and acting accordingly. This paper gives a brief overview of different assessment rules for indirect reciprocity, and studies them by using evolutionary game dynamics. Even the simplest binary assessment rules lead to complex outcomes and require considerable cognitive abilities.

  16. Compressor Flow Control Concepts. 2; UEET Compressor Flow Control Modeling

    NASA Technical Reports Server (NTRS)

    Chima, Rodrick V.

    2001-01-01

    Several passive flow control devices have been modeled computationally in the Swift CFD code. The models were applied to the first stage rotor and stator of the baseline UEET compressor in an attempt to improve efficiency and/or stall margin. The devices included suction surface bleed, tip injection, self-aspirated rotors, area-ruled casing, and vortex generators. The models and computed results will be described in the presentation. None of the results have shown significant gains in efficiency; however, casing vortex generators have shown potential improvements in stall margin.

  17. Advanced Natural Gas Reciprocating Engine(s)

    SciTech Connect

    Kwok, Doris; Boucher, Cheryl

    2009-09-30

    Energy independence and fuel savings are hallmarks of the nation’s energy strategy. The advancement of natural gas reciprocating engine power generation technology is critical to the nation’s future. A new engine platform that meets the efficiency, emissions, fuel flexibility, cost and reliability/maintainability targets will enable American manufacturers to have highly competitive products that provide substantial environmental and economic benefits in the US and in international markets. Along with Cummins and Waukesha, Caterpillar participated in a multiyear cooperative agreement with the Department of Energy to create a 50% efficiency natural gas powered reciprocating engine system with a 95% reduction in NOx emissions by the year 2013. This platform developed under this agreement will be a significant contributor to the US energy strategy and will enable gas engine technology to remain a highly competitive choice, meeting customer cost of electricity targets, and regulatory environmental standard. Engine development under the Advanced Reciprocating Engine System (ARES) program was divided into phases, with the ultimate goal being approached in a series of incremental steps. This incremental approach would promote the commercialization of ARES technologies as soon as they emerged from development and would provide a technical and commercial foundation of later-developing technologies. Demonstrations of the Phase I and Phase II technology were completed in 2004 and 2008, respectively. Program tasks in Phase III included component and system development and testing from 2009-2012. Two advanced ignition technology evaluations were investigated under the ARES program: laser ignition and distributed ignition (DIGN). In collaboration with Colorado State University (CSU), a laser ignition system was developed to provide ignition at lean burn and high boost conditions. Much work has been performed in Caterpillar’s DIGN program under the ARES program. This work

  18. Regenerative sorption compressors for cryogenic refrigeration

    NASA Technical Reports Server (NTRS)

    Bard, Steven; Jones, Jack A.

    1990-01-01

    Dramatic efficiency improvements for sorption coolers appear possible with use of compressor heat regeneration techniques. The general theory of sorption compressor heat regeneration is discussed in this paper, and several design concepts are presented. These designs result in long-life, low-vibration cryocoolers that potentially have efficiencies comparable to Stirling refrigerators for 65 to 90 K spacecraft instrument cooling applications.

  19. Tolerances of TTF-2 First Bunch Compressor

    SciTech Connect

    Emma, Paul J

    2003-08-08

    In bunch compressors for SASE-FEL facilities, the projected transverse emittance can be diluted by magnetic multipole component errors in dipoles and dipole misalignments as well as by coherent synchrotron radiation (CSR). In this paper, we describe the multipole field tolerances and the misalignment tolerances of the first bunch compressor (BC2) for the TESLA Test Facility Phase-2 (TTF-2).

  20. Scroll Compressor Oil Pump Analysis

    NASA Astrophysics Data System (ADS)

    Branch, S.

    2015-08-01

    Scroll compressors utilize three journal bearings to absorb gas, friction and inertial loads exerted on the crankshaft. To function properly, these bearings must be lubricated with a certain amount of oil. The focus of this paper will be to discuss how computational fluid dynamics can be used to predict oil flow out of a single-stage oil pump. The effects of speed and lubricant viscosity on pump output will also be presented. The comparisons will look at mass flow rates, differences in pressure, and torque at various speeds and dynamic viscosities. The computational fluid dynamic analysis results will be compared with actual lab testing where a crankshaft bench tester was built.

  1. Centrifugal compressor design for electrically assisted boost

    NASA Astrophysics Data System (ADS)

    Y Yang, M.; Martinez-Botas, R. F.; Zhuge, W. L.; Qureshi, U.; Richards, B.

    2013-12-01

    Electrically assisted boost is a prominent method to solve the issues of transient lag in turbocharger and remains an optimized operation condition for a compressor due to decoupling from turbine. Usually a centrifugal compressor for gasoline engine boosting is operated at high rotational speed which is beyond the ability of an electric motor in market. In this paper a centrifugal compressor with rotational speed as 120k RPM and pressure ratio as 2.0 is specially developed for electrically assisted boost. A centrifugal compressor including the impeller, vaneless diffuser and the volute is designed by meanline method followed by 3D detailed design. Then CFD method is employed to predict as well as analyse the performance of the design compressor. The results show that the pressure ratio and efficiency at design point is 2.07 and 78% specifically.

  2. Axial flow positive displacement worm compressor

    NASA Technical Reports Server (NTRS)

    Murrow, Kurt David (Inventor); Giffin, Rollin George (Inventor); Fakunle, Oladapo (Inventor)

    2010-01-01

    An axial flow positive displacement compressor has an inlet axially spaced apart and upstream from an outlet. Inner and outer bodies have offset inner and outer axes extend from the inlet to the outlet through first and second sections of a compressor assembly in serial downstream flow relationship. At least one of the bodies is rotatable about its axis. The inner and outer bodies have intermeshed inner and outer helical blades wound about the inner and outer axes respectively. The inner and outer helical blades extend radially outwardly and inwardly respectively. The helical blades have first and second twist slopes in the first and second sections respectively. The first twist slopes are less than the second twist slopes. An engine including the compressor has in downstream serial flow relationship from the compressor a combustor and a high pressure turbine drivingly connected to the compressor by a high pressure shaft.

  3. Refrigeration system having standing wave compressor

    DOEpatents

    Lucas, Timothy S.

    1992-01-01

    A compression-evaporation refrigeration system, wherein gaseous compression of the refrigerant is provided by a standing wave compressor. The standing wave compressor is modified so as to provide a separate subcooling system for the refrigerant, so that efficiency losses due to flashing are reduced. Subcooling occurs when heat exchange is provided between the refrigerant and a heat pumping surface, which is exposed to the standing acoustic wave within the standing wave compressor. A variable capacity and variable discharge pressure for the standing wave compressor is provided. A control circuit simultaneously varies the capacity and discharge pressure in response to changing operating conditions, thereby maintaining the minimum discharge pressure needed for condensation to occur at any time. Thus, the power consumption of the standing wave compressor is reduced and system efficiency is improved.

  4. Transient phenomena in compressor stations during surge

    SciTech Connect

    Botros, K.K. )

    1994-01-01

    Transient phenomena are generally inherent in the operation of compressor stations: These are either fast or slow transients. A model describing the governing equation for the gas dynamics, control system, compressor and turbine shaft inertias has been developed. The effect of these inertias is manifested by an example of a compressor station operating near the surge control line. Another example deals with a station that has a cooler placed in the recycle path. This alters the rate at which the compressor shaft decelerates upon shutdown and may cause backward spinning depending on the relative magnitude of the shaft inertia with respect to the cooler volume. Backward spinning of compressor shaft has detrimental effects on dry seals and is undesirable. It was found that by keeping the recycle value closed upon shutdown, the rate of shaft deceleration will be reduced.

  5. Technique for rapid inspection of hermetic seals of microelectronic packages using shearography

    NASA Astrophysics Data System (ADS)

    Hung, Y. (Michael) Y.; Shi, Dahuan

    1998-05-01

    One possible failure of microelectronic devices is due to leakage resulting from an imperfect hermetical seal in microelectronic packages such as microchips. This malfunction is often experienced in automobiles in which the electronic devices are exposed to hostile environments. Traditional leak-testing methods are very time consuming. A shearographic technique for rapid evaluation of hermetic seals is presented. The package under test is stressed by an external pressure change. With the pressure change maintained, the lid of a perfectly sealed package will remain deformed while a leaky package will not hold the deformation, which can be monitored by shearography. This leak testing is fast and practical and can be extended to testing pharmaceutical packages, food packages, etc.

  6. Low-temperature thin-film indium bonding for reliable wafer-level hermetic MEMS packaging

    NASA Astrophysics Data System (ADS)

    Straessle, R.; Pétremand, Y.; Briand, D.; Dadras, M.; de Rooij, N. F.

    2013-07-01

    This paper reports on low-temperature and hermetic thin-film indium bonding for wafer-level encapsulation and packaging of delicate and temperature sensitive devices. This indium-bonding technology enables bonding of surface materials commonly used in MEMS technology. The temperature is kept below 140 °C for all process steps and no surface treatment is applied before and during bonding. This bonding technology allows hermetic sealing at 140 °C with a leak rate below 4 × 10-12 mbar l s-1 at room temperature. The tensile strength of the bonds up to 25 MPa goes along with a very high yield.

  7. Direct reciprocity in structured populations.

    PubMed

    van Veelen, Matthijs; García, Julián; Rand, David G; Nowak, Martin A

    2012-06-19

    Reciprocity and repeated games have been at the center of attention when studying the evolution of human cooperation. Direct reciprocity is considered to be a powerful mechanism for the evolution of cooperation, and it is generally assumed that it can lead to high levels of cooperation. Here we explore an open-ended, infinite strategy space, where every strategy that can be encoded by a finite state automaton is a possible mutant. Surprisingly, we find that direct reciprocity alone does not lead to high levels of cooperation. Instead we observe perpetual oscillations between cooperation and defection, with defection being substantially more frequent than cooperation. The reason for this is that "indirect invasions" remove equilibrium strategies: every strategy has neutral mutants, which in turn can be invaded by other strategies. However, reciprocity is not the only way to promote cooperation. Another mechanism for the evolution of cooperation, which has received as much attention, is assortment because of population structure. Here we develop a theory that allows us to study the synergistic interaction between direct reciprocity and assortment. This framework is particularly well suited for understanding human interactions, which are typically repeated and occur in relatively fluid but not unstructured populations. We show that if repeated games are combined with only a small amount of assortment, then natural selection favors the behavior typically observed among humans: high levels of cooperation implemented using conditional strategies.

  8. Indirect Reciprocity; A Field Experiment

    PubMed Central

    van Apeldoorn, Jacobien; Schram, Arthur

    2016-01-01

    Indirect reciprocity involves cooperative acts towards strangers, either in response to their kindness to third parties (downstream) or after receiving kindness from others oneself (upstream). It is considered to be important for the evolution of cooperative behavior amongst humans. Though it has been widely studied theoretically, the empirical evidence of indirect reciprocity has thus far been limited and based solely on behavior in laboratory experiments. We provide evidence from an online environment where members can repeatedly ask and offer services to each other, free of charge. For the purpose of this study we created several new member profiles, which differ only in terms of their serving history. We then sent out a large number of service requests to different members from all over the world. We observe that a service request is more likely to be rewarded for those with a profile history of offering the service (to third parties) in the past. This provides clear evidence of (downstream) indirect reciprocity. We find no support for upstream indirect reciprocity (in this case, rewarding the service request after having previously received the service from third parties), however. Our evidence of downstream indirect reciprocity cannot be attributed to reputational effects concerning one’s trustworthiness as a service user. PMID:27043712

  9. Development of Metallic Hermetic Sealing for MEMS Packaging for Harsh Environment Applications

    NASA Astrophysics Data System (ADS)

    Chidambaram, Vivek; Yeung, Ho Beng; Shan, Gao

    2012-08-01

    Hermetic sealing of microelectromechanical system sensors is indispensable to ensure their reliable operation and also to provide protection during fabrication. This work proposes two prospective candidates for hermetic sealing for rugged environment applications, i.e., Al-Ge and Pt-In. Al-Ge was chosen due to its compatibility with complementary metal-oxide-semiconductor technology. Pt-In possesses the highest remelting temperature among all the solder systems, which is desired for high-temperature applications in both the energy and aerospace industries. The various bonding parameters for Al-Ge eutectic bonding and Pt-In transient liquid-phase (TLP) bonding have been optimized, and their influence on the bond quality is reported. Optimization of bonding parameters has been carried out with the objective of ensuring void-free bonds. A new configuration for stacking Al-Ge thin films has been demonstrated to tackle the issue of loss of Ge prior to bonding, since native Ge oxides are soluble in deionized water. The impact of solid-state aging prior to Al-Ge eutectic bonding has been investigated. The method of tailoring the phases in the Pt-In joint is also discussed. The prospects and constraints of eutectic and TLP bonding from the hermeticity perspective are discussed in detail. Furthermore, changes in the microstructure under aging at 300°C up to 500 h and the resulting influence on the mechanical properties are presented. The overall finding of this work is that Al-Ge can achieve better mechanical and hermetic performance for high-temperature applications.

  10. Hermetic electronic packaging of an implantable brain-machine-interface with transcutaneous optical data communication.

    PubMed

    Schuettler, Martin; Kohler, Fabian; Ordonez, Juan S; Stieglitz, Thomas

    2012-01-01

    Future brain-computer-interfaces (BCIs) for severely impaired patients are implanted to electrically contact the brain tissue. Avoiding percutaneous cables requires amplifier and telemetry electronics to be implanted too. We developed a hermetic package that protects the electronic circuitry of a BCI from body moisture while permitting infrared communication through the package wall made from alumina ceramic. The ceramic package is casted in medical grade silicone adhesive, for which we identified MED2-4013 as a promising candidate.

  11. Assortment and the evolution of generalized reciprocity.

    PubMed

    Rankin, Daniel J; Taborsky, Michael

    2009-07-01

    Reciprocity is often invoked to explain cooperation. Reciprocity is cognitively demanding, and both direct and indirect reciprocity require that individuals store information about the propensity of their partners to cooperate. By contrast, generalized reciprocity, wherein individuals help on the condition that they received help previously, only relies on whether an individual received help in a previous encounter. Such anonymous information makes generalized reciprocity hard to evolve in a well-mixed population, as the strategy will lose out to pure defectors. Here we analyze a model for the evolution of generalized reciprocity, incorporating assortment of encounters, to investigate the conditions under which it will evolve. We show that, in a well-mixed population, generalized reciprocity cannot evolve. However, incorporating assortment of encounters can favor the evolution of generalized reciprocity in which indiscriminate cooperation and defection are both unstable. We show that generalized reciprocity can evolve under both the prisoner's dilemma and the snowdrift game.

  12. 49 CFR 192.163 - Compressor stations: Design and construction.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ..., each main compressor building of a compressor station must be located on property under the control of... property. There must be enough open space around the main compressor building to allow the free movement of fire-fighting equipment. (b) Building construction. Each building on a compressor station site must...

  13. 49 CFR 192.163 - Compressor stations: Design and construction.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ..., each main compressor building of a compressor station must be located on property under the control of... property. There must be enough open space around the main compressor building to allow the free movement of fire-fighting equipment. (b) Building construction. Each building on a compressor station site must...

  14. 49 CFR 192.736 - Compressor stations: Gas detection.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 3 2011-10-01 2011-10-01 false Compressor stations: Gas detection. 192.736... Compressor stations: Gas detection. (a) Not later than September 16, 1996, each compressor building in a compressor station must have a fixed gas detection and alarm system, unless the building is— (1)...

  15. 40 CFR 60.482-3 - Standards: Compressors.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 6 2010-07-01 2010-07-01 false Standards: Compressors. 60.482-3... Standards: Compressors. (a) Each compressor shall be equipped with a seal system that includes a barrier... paragraphs (h), (i), and (j) of this section. (b) Each compressor seal system as required in paragraph...

  16. Development and testing of hermetic, laser-ignited pyrotechnic and explosive components

    NASA Technical Reports Server (NTRS)

    Kramer, Daniel P.; Beckman, Thomas M.; Spangler, Ed M.; Munger, Alan C.; Woods, C. M.

    1993-01-01

    During the last decade there has been increasing interest in the use of lasers in place of electrical systems to ignite various pyrotechnic and explosive materials. The principal driving force for this work was the requirement for safer energetic components which would be insensitive to electrostatic and electromagnetic radiation. In the last few years this research has accelerated since the basic concepts have proven viable. At the present time it is appropriate to shift the research emphasis in laser initiation from the scientific arena--whether it can be done--to the engineering realm--how it can be put into actual practice in the field. Laser initiation research and development at EG&G Mound was in three principal areas: (1) laser/energetic material interactions; (2) development of novel processing techniques for fabricating hermetic (helium leak rate of less than 1 x 10(exp -8) cu cm/s) laser components; and (3) evaluation and testing of laser-ignited components. Research in these three areas has resulted in the development of high quality, hermetic, laser initiated components. Examples are presented which demonstrate the practicality of fabricating hermetic, laser initiated explosive or pyrotechnic components that can be used in the next generation of ignitors, actuators, and detonators.

  17. An all-diamond, hermetic electrical feedthrough array for a retinal prosthesis.

    PubMed

    Ganesan, Kumaravelu; Garrett, David J; Ahnood, Arman; Shivdasani, Mohit N; Tong, Wei; Turnley, Ann M; Fox, Kate; Meffin, Hamish; Prawer, Steven

    2014-01-01

    The interface between medical implants and the human nervous system is rapidly becoming more and more complex. This rise in complexity is driving the need for increasing numbers of densely packed electrical feedthrough to carry signals to and from implanted devices. This is particularly crucial in the field of neural prosthesis where high resolution stimulating or recording arrays near peripheral nerves or in the brain could dramatically improve the performance of these devices. Here we describe a flexible strategy for implementing high density, high count arrays of hermetic electrical feedthroughs by forming conducting nitrogen doped nanocrystalline diamond channels within an insulating polycrystalline diamond substrate. A unique feature of these arrays is that the feedthroughs can themselves be used as stimulating electrodes for neural tissue. Our particular application is such a feedthrough, designed as a component of a retinal implant to restore vision to the blind. The hermeticity of the feedthroughs means that the array can also form part of an implantable capsule which can interface directly with internal electronic chips. The hermeticity of the array is demonstrated by helium leak tests and electrical and electrochemical characterisation of the feedthroughs is described. The nitrogen doped nanocrystalline diamond forming the electrical feedthroughs is shown to be non-cyctotoxic. New fabrication strategies, such as the one described here, combined with the exceptional biostability of diamond can be exploited to generate a range of biomedical implants that last for the lifetime of the user without fear of degradation.

  18. Communication and Control System for a 15-Channel Hermetic Retinal Prosthesis

    PubMed Central

    Kelly, Shawn K.; Shire, Douglas B.; Chen, Jinghua; Doyle, Patrick; Gingerich, Marcus D.; Cogan, Stuart F.; Drohan, William A.; Theogarajan, Luke S.; Wyatt, John L.; Rizzo, Joseph F.

    2011-01-01

    A small, hermetic, wirelessy-controlled retinal prosthesis has been developed for pre-clinical studies in Yucatan minipigs. The device was attached conformally to the outside of the eye in the socket and received both power and data wirelessly from external sources. Based on the received image data, the prosthesis drove a subretinal thin-film polyimide array of sputtered iridium oxide stimulating electrodes. The implanted device included a hermetic titanium case containing a 15-channel stimulator and receiver chip and discrete circuit components. Feedthroughs in the hermetic case connected the chip to secondary power- and data-receiving coils, which coupled to corresponding external power and data coils driven by power amplifiers. Power was delivered by a 125 KHz carrier, and data were delivered by amplitude shift keying of a 15.5 MHz carrier at 100 Kbps. Stimulation pulse strength, duration and frequency were programmed wirelessly from an external computer system. The final assembly was tested in vitro in physiological saline and in vivo in two minipigs for up to five and a half months by measuring stimulus artifacts generated by the implant’s current drivers. PMID:21927618

  19. The NLC L-Band Bunch Compressor

    SciTech Connect

    Emma, Paul J

    2002-08-21

    The first stage bunch compressor in the NLC injector complex compresses the e+/e- beams from a bunch length of 5 mm rms to 0.5 mm rms at the beam energy of 2 GeV. To obtain this compression ratio, the compressor rf section operates with an rf frequency of 1.4 GHz and a voltage of about 140 MV while a magnetic wiggler is used to generate an R{sub 56} = 0.5 m. The bunch compressor is designed to operate with a beam from the damping ring that has a bunch spacing slew of 20ps across the bunch train due to the transient loading in the damping rings. The compressor RF section is required to produce a specific energy profile along the bunch train so that the bunch spacing can be corrected in the compressor bending section. Further, the 1-amp beam heavily loads the compressor linac and beam loading compensation is essential to prevent a phase variation along the bunch train in the downstream linacs. In this paper, we will present simulation results of the beam loading compensation using a {Delta}T scheme assuming various initial bunch spacing arrangements. We will study the impact of the different compressor energy profiles on the beam energy, energy spread, and bunch length at the IP.

  20. On-Orbit Compressor Technology Program

    NASA Technical Reports Server (NTRS)

    Deffenbaugh, Danny M.; Svedeman, Steven J.; Schroeder, Edgar C.; Gerlach, C. Richard

    1990-01-01

    A synopsis of the On-Orbit Compressor Technology Program is presented. The objective is the exploration of compressor technology applicable for use by the Space Station Fluid Management System, Space Station Propulsion System, and related on-orbit fluid transfer systems. The approach is to extend the current state-of-the-art in natural gas compressor technology to the unique requirements of high-pressure, low-flow, small, light, and low-power devices for on-orbit applications. This technology is adapted to seven on-orbit conceptual designs and one prototype is developed and tested.

  1. Investigation of axial positioning for flexural compressors

    NASA Technical Reports Server (NTRS)

    Riggle, Peter

    1991-01-01

    The testing of the research compressor is presented. The research compressor was assembled and disassembled in order to show the consistency in which the piston and rod could be aligned with a .0004 inch radial gap around the piston. A full set of tests was completed for the first assembly, which is referred to as assembly no. 1. The compressor was disassembled and assembled a second time (assembly no. 2). Assembly no. 2 was only tested statically due to the time constraint. Results are discussed.

  2. Water ingestion into jet engine axial compressors

    NASA Technical Reports Server (NTRS)

    Tsuchiya, T.; Murthy, S. N. B.

    1982-01-01

    An axial flow compressor has been tested with water droplet ingestion under a variety of conditions. The results illustrate the manner in which the compressor pressure ratio, efficiency and surging characteristics are affected. A model for estimating the performance of a compressor during water ingestion has been developed and the predictions obtained compare favorably with the test results. It is then shown that with respect to five droplet-associated nonlinearly-interacting processes (namely, droplet-blade interactions, blade performance changes, centrifugal action, heat and mass transfer processes and droplet break-up), the initial water content and centrifugal action play the most dominant roles.

  3. Integrated Heat Switch/Oxide Sorption Compressor

    NASA Technical Reports Server (NTRS)

    Bard, Steven

    1989-01-01

    Thermally-driven, nonmechanical compressor uses container filled with compressed praseodymium cerium oxide powder (PrCeOx) to provide high-pressure flow of oxygen gas for driving closed-cycle Joule-Thomson-expansion refrigeration unit. Integrated heat switch/oxide sorption compressor has no moving parts except check valves, which control flow of oxygen gas between compressor and closed-cycle Joule-Thomson refrigeration system. Oxygen expelled from sorbent at high pressure by evacuating heat-switch gap and turning on heater.

  4. Compressor Has No Moving Macroscopic Parts

    NASA Technical Reports Server (NTRS)

    Gasser, Max

    1995-01-01

    Compressor containing no moving macroscopic parts functions by alternating piston and valve actions of successive beds of magnetic particles. Fabricated easily because no need for precisely fitting parts rotating or sliding on each other. Also no need for lubricant fluid contaminating fluid to be compressed. Compressor operates continuously, eliminating troublesome on/off cycling of other compressors, and decreasing consumption of energy. Phased cells push fluid from bottom to top, adding increments of pressure. Each cell contains magnetic powder particles loose when electromagnet coil deenergized, but tightly packed when coil energized.

  5. Improved Regenerative Sorbent-Compressor Refrigerator

    NASA Technical Reports Server (NTRS)

    Jones, Jack A.

    1992-01-01

    Conceptual regenerative sorbent-compressor refrigerator attains regeneration efficiency and, therefore, overall power efficiency and performance greater than conventional refrigerators. Includes two fluid loops. In one, CH2FCF3 (R134a) ciculates by physical adsorption and desorption in four activated-charcoal sorption compressors. In other, liquid or gas coolant circulated by pump. Wave of regenerative heating and cooling propagates cyclically like peristatic wave among sorption compressors and associated heat exchangers. Powered by electricity, oil, gas, solar heat, or waste heat. Used as air conditioners, refrigerators, and heat pumps in industrial, home, and automotive applications.

  6. CSR instability in a Bunch Compressor

    NASA Astrophysics Data System (ADS)

    Stupakov, G. V.

    2002-03-01

    The coherent synchrotron radiation of a bunch in a bunch compressor may lead to the microwave instability producing longitudinal modulation of the bunch with wavelengths small compared to the bunch length. It can also be a source of an undesirable emittance growth in the compressor. We derive and analyze the equation that describes linear evolution of the microwave modulation taking into account incoherent energy spread and nite emittance of the beam. Numerical solution of this equatierenton for the LCLS (Linac Coherent Light Source) bunch compressor gives the amplication factor for different wavelengths of the beam microbunching.

  7. CSR instability in a Bunch Compressor

    SciTech Connect

    Stupakov, Gennady V.

    2002-03-19

    The coherent synchrotron radiation of a bunch in a bunch compressor may lead to the microwave instability producing longitudinal modulation of the bunch with wavelengths small compared to the bunch length. It can also be a source of an undesirable emittance growth in the compressor. We derive and analyze the equation that describes linear evolution of the microwave modulation taking into account incoherent energy spread and finite emittance of the beam. Numerical solution of this equation for the LCLS bunch compressor gives the amplification factor for different wavelengths of the beam microbunching.

  8. Commissioning of the SPPS Linac Bunch Compressor

    SciTech Connect

    Krejcik, Patrick

    2003-05-21

    First results and beam measurements are presented for the recently installed linac bunch compressor chicane. The new bunch compressor produces ultra-short electron bunches for the Sub-Picosecond Photon Source (SPPS) and for test beams such as the E164 Plasma Wakefield experiment. This paper will give an overview of the first experiences with tuning and optimizing the compressor together with a description of the beam diagnostics and beam measurements. These measurements form the basis for further detailed study of emittance growth effects such as CSR and wakefields in a previously unmeasured regime of ultra-short bunch lengths.

  9. Cost-efficient hermetic fibre pigtailed laser module utilizing passive device alignment on an LTCC substrate

    NASA Astrophysics Data System (ADS)

    Keränen, K.; Ollila, J.; Mäkinen, J.-T.; Kautio, K.; Korhonen, P.; Heikkinen, V.; Väätäinen, O.; Heilala, J.; Karioja, P.

    2006-04-01

    A hermetic fibre pigtailed laser module utilizing passive device alignment on a low temperature co-fired ceramics (LTCC) substrate is demonstrated. The 3-dimensional shape of the laminated and fired ceramic substrate provides the necessary alignment structures including holes, grooves and cavities for the laser to fibre coupling. The achieved passive alignment accuracy allows high coupling efficiency realizations of multi-mode fibre pigtailed laser modules. The ceramic substrate is intrinsically hermetic and it opens up a possibility to produce cost efficient hermetic packaging. In our concept hermetic sealing is produced by utilizing Kovar frame, which is soldered to an LTCC substrate. Kovar frame has a hole for fibre feed-trough and a hermetic glass-metal sealing between fibre and frame is processed using glass preform. The heart of the module is a power laser diode chip, which can produce several watts of continuous power. The module, however, can be finally used as a transmitter in a laser pulse time-of-flight distance sensor and in this application it can be overdriven by a factor of 10. This means that the peak optical power in the pulses can be several tens of watts. The laser chip allows this kind of overdriving due to the fact that the duty factor in the operation is only 0.0001 at 2 kHz pulsing frequency. Optical coupling efficiency of the multi-mode laser system was simulated using optical systems simulation software. The nominal coupling efficiency between 210 μm x 1μm stripe laser and 200/220 μm step index fibre (NA=0.22) was 0.65. The simulated coupling efficiency was verified by prototype realization and characterization. The measured average coupling efficiency of the hermetically sealed prototypes was 0.39. The coupling efficiencies of prototypes varied from 0.14 to 0.64. Leak rate of 1 x 10 -7 [atm x cm 3/s] was measured in the helium leak tests for the final prototype module, when the module was tested according to MIL-STD-883D method 1014

  10. Indirect reciprocity with optional interactions.

    PubMed

    Ghang, Whan; Nowak, Martin A

    2015-01-21

    Indirect reciprocity is a mechanism for the evolution of cooperation that is relevant for prosocial behavior among humans. Indirect reciprocity means that my behavior towards you also depends on what you have done to others. Indirect reciprocity is associated with the evolution of social intelligence and human language. Most approaches to indirect reciprocity assume obligatory interactions, but here we explore optional interactions. In any one round a game between two players is offered. A cooperator accepts a game unless the reputation of the other player indicates a defector. For a game to take place, both players must accept. In a game between a cooperator and a defector, the reputation of the defector is revealed to all players with probability Q. After a sufficiently large number of rounds the identity of all defectors is known and cooperators are no longer exploited. The crucial condition for evolution of cooperation can be written as hQB>1, where h is the average number of rounds per person and B=(b/c)-1 specifies the benefit-to-cost ratio. We analyze both stochastic and deterministic evolutionary game dynamics. We study two extensions that deal with uncertainty: hesitation and malicious gossip.

  11. Do infants detect indirect reciprocity?

    PubMed

    Meristo, Marek; Surian, Luca

    2013-10-01

    In social interactions involving indirect reciprocity, agent A acts prosocially towards B and this prompts C to act prosocially towards A. This happens because A's actions enhanced its reputation in the eyes of third parties. Indirect reciprocity may have been of central importance in the evolution of morality as one of the major mechanisms leading to the selection of helping and fair attitudes. Here we show that 10-month-old infants expect third parties to act positively towards fair donors who have distributed attractive resources equally between two recipients, rather than toward unfair donors who made unequal distributions. Infants' responses were dependent on the reciprocator's perceptual exposure to previous relevant events: they expected the reciprocator to reward the fair donor only when it had seen the distributive actions performed by the donors. We propose that infants were able to generate evaluations of agents that were based on the fairness of their distributive actions and to generate expectations about the social preferences of informed third parties.

  12. Indirect reciprocity under incomplete observation.

    PubMed

    Nakamura, Mitsuhiro; Masuda, Naoki

    2011-07-01

    Indirect reciprocity, in which individuals help others with a good reputation but not those with a bad reputation, is a mechanism for cooperation in social dilemma situations when individuals do not repeatedly interact with the same partners. In a relatively large society where indirect reciprocity is relevant, individuals may not know each other's reputation even indirectly. Previous studies investigated the situations where individuals playing the game have to determine the action possibly without knowing others' reputations. Nevertheless, the possibility that observers of the game, who generate the reputation of the interacting players, assign reputations without complete information about them has been neglected. Because an individual acts as an interacting player and as an observer on different occasions if indirect reciprocity is endogenously sustained in a society, the incompleteness of information may affect either role. We examine the game of indirect reciprocity when the reputations of players are not necessarily known to observers and to interacting players. We find that the trustful discriminator, which cooperates with good and unknown players and defects against bad players, realizes cooperative societies under seven social norms. Among the seven social norms, three of the four suspicious norms under which cooperation (defection) to unknown players leads to a good (bad) reputation enable cooperation down to a relatively small observation probability. In contrast, the three trustful norms under which both cooperation and defection to unknown players lead to a good reputation are relatively efficient.

  13. Reciprocity theory of homogeneous reactions

    NASA Astrophysics Data System (ADS)

    Agbormbai, Adolf A.

    1990-03-01

    The reciprocity formalism is applied to the homogeneous gaseous reactions in which the structure of the participating molecules changes upon collision with one another, resulting in a change in the composition of the gas. The approach is applied to various classes of dissociation, recombination, rearrangement, ionizing, and photochemical reactions. It is shown that for the principle of reciprocity to be satisfied it is necessary that all chemical reactions exist in complementary pairs which consist of the forward and backward reactions. The backward reaction may be described by either the reverse or inverse process. The forward and backward processes must satisfy the same reciprocity equation. Because the number of dynamical variables is usually unbalanced on both sides of a chemical equation, it is necessary that this balance be established by including as many of the dynamical variables as needed before the reciprocity equation can be formulated. Statistical transformation models of the reactions are formulated. The models are classified under the titles free exchange, restricted exchange and simplified restricted exchange. The special equations for the forward and backward processes are obtained. The models are consistent with the H theorem and Le Chatelier's principle. The models are also formulated in the context of the direct simulation Monte Carlo method.

  14. Reciprocity and Humility in Wonderland

    ERIC Educational Resources Information Center

    Harry, Beth

    2011-01-01

    This article supports the perspective of Jan Valle regarding the importance of recognizing the subjectivity inherent in decisions about Learning Disabilities. The author argues that the perspectives of both parents and professionals are informed by subjective judgments that must be taken into account in decision making. A reciprocal approach to…

  15. Dynamically balanced, hydraulically driven compressor/pump apparatus for resonant free piston Stirling engines

    DOEpatents

    Corey, John A.

    1984-05-29

    A compressor, pump, or alternator apparatus is designed for use with a resonant free piston Stirling engine so as to isolate apparatus fluid from the periodically pressurized working fluid of the Stirling engine. The apparatus housing has a first side closed by a power coupling flexible diaphragm (the engine working member) and a second side closed by a flexible diaphragm gas spring. A reciprocally movable piston is disposed in a transverse cylinder in the housing and moves substantially at right angles relative to the flexible diaphragms. An incompressible fluid fills the housing which is divided into two separate chambers by suitable ports. One chamber provides fluid coupling between the power diaphragm of the RFPSE and the piston and the second chamber provides fluid coupling between the gas spring diaphragm and the opposite side of the piston. The working members of a gas compressor, pump, or alternator are driven by the piston. Sealing and wearing parts of the apparatus are mounted at the external ends of the transverse cylinder in a double acting arrangement for accessibility. An annular counterweight is mounted externally of the reciprocally movable piston and is driven by incompressible fluid coupling in a direction opposite to the piston so as to damp out transverse vibrations.

  16. Method and apparatus for starting supersonic compressors

    SciTech Connect

    Lawlor, Shawn P

    2013-08-06

    A supersonic gas compressor with bleed gas collectors, and a method of starting the compressor. The compressor includes aerodynamic duct(s) situated for rotary movement in a casing. The aerodynamic duct(s) generate a plurality of oblique shock waves for efficiently compressing a gas at supersonic conditions. A convergent inlet is provided adjacent to a bleed gas collector, and during startup of the compressor, bypass gas is removed from the convergent inlet via the bleed gas collector, to enable supersonic shock stabilization. Once the oblique shocks are stabilized at a selected inlet relative Mach number and pressure ratio, the bleed of bypass gas from the convergent inlet via the bypass gas collectors is effectively eliminated.

  17. A Compliant Casing for Transonic Axial Compressors

    NASA Technical Reports Server (NTRS)

    Bloch, Gregory S.; Hah, Chunill

    2003-01-01

    A viewgraph presentation on the concept of compliant casing for transonic axial compressors is shown. The topics include: 1) Concept for compliant casing; 2) Rig and facility details; 3) Experimental results; and 4) Numerical results.

  18. 40 CFR 265.1053 - Standards: Compressors.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... (CONTINUED) INTERIM STATUS STANDARDS FOR OWNERS AND OPERATORS OF HAZARDOUS WASTE TREATMENT, STORAGE, AND DISPOSAL FACILITIES Air Emission Standards for Equipment Leaks § 265.1053 Standards: Compressors. (a)...

  19. 40 CFR 265.1053 - Standards: Compressors.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... (CONTINUED) INTERIM STATUS STANDARDS FOR OWNERS AND OPERATORS OF HAZARDOUS WASTE TREATMENT, STORAGE, AND DISPOSAL FACILITIES Air Emission Standards for Equipment Leaks § 265.1053 Standards: Compressors. (a)...

  20. 40 CFR 265.1053 - Standards: Compressors.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... (CONTINUED) INTERIM STATUS STANDARDS FOR OWNERS AND OPERATORS OF HAZARDOUS WASTE TREATMENT, STORAGE, AND DISPOSAL FACILITIES Air Emission Standards for Equipment Leaks § 265.1053 Standards: Compressors. (a)...

  1. 40 CFR 265.1053 - Standards: Compressors.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... (CONTINUED) INTERIM STATUS STANDARDS FOR OWNERS AND OPERATORS OF HAZARDOUS WASTE TREATMENT, STORAGE, AND DISPOSAL FACILITIES Air Emission Standards for Equipment Leaks § 265.1053 Standards: Compressors. (a)...

  2. Abradable compressor and turbine seals, volume 2

    NASA Technical Reports Server (NTRS)

    Sundberg, D. V.; Dennis, R. E.; Hurst, L. G.

    1979-01-01

    The applications and advantages of abradable coatings as gas path seals in a general aviation turbofan engine were investigated. Abradable materials were evaluated for the high pressure radial compressor and the axial high and low pressure turbine shrouds.

  3. Refrigeration system having dual suction port compressor

    DOEpatents

    Wu, Guolian

    2016-01-05

    A cooling system for appliances, air conditioners, and other spaces includes a compressor, and a condenser that receives refrigerant from the compressor. The system also includes an evaporator that receives refrigerant from the condenser. Refrigerant received from the condenser flows through an upstream portion of the evaporator. A first portion of the refrigerant flows to the compressor without passing through a downstream portion of the evaporator, and a second portion of the refrigerant from the upstream portion of the condenser flows through the downstream portion of the evaporator after passing through the upstream portion of the evaporator. The second portion of the refrigerant flows to the compressor after passing through the downstream portion of the evaporator. The refrigeration system may be configured to cool an appliance such as a refrigerator and/or freezer, or it may be utilized in air conditioners for buildings, motor vehicles, or other such spaces.

  4. Electrochemical oxygen concentrator as an oxygen compressor

    NASA Technical Reports Server (NTRS)

    1975-01-01

    A solid polymer electrolyte (SPE) oxygen compressor is described which generates pressures of 3000 psi. The SPE is a cation exchange membrane with chemical compatibility, and has the capability of withstanding 5000 psi. Other features of the compressor described include: gasketless sealing, porus plate cell supports, and conductive cooling. Results are presented of a computer program which defines the power of the system as a function of density, temperature, pressure, membrane thickness, and water content.

  5. An Inquiry into Relationship Suicides and Reciprocity

    ERIC Educational Resources Information Center

    Davis, Mark S.; Callanan, Valerie J.; Lester, David; Haines, Janet

    2009-01-01

    Few theories on suicide have been grounded in the norm of reciprocity. There is literature on suicide, however, describing motivations such as retaliation and retreat which can be interpreted as modes of adaptation to the norm of reciprocity. We propose a reciprocity-based theory to explain suicides associated with relationship problems. Employing…

  6. 47 CFR 51.221 - Reciprocal compensation.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 3 2010-10-01 2010-10-01 false Reciprocal compensation. 51.221 Section 51.221... Obligations of All Local Exchange Carriers § 51.221 Reciprocal compensation. The rules governing reciprocal compensation are set forth in subpart H of this part....

  7. Capuchin Monkeys Judge Third-Party Reciprocity

    ERIC Educational Resources Information Center

    Anderson, James R.; Takimoto, Ayaka; Kuroshima, Hika; Fujita, Kazuo

    2013-01-01

    Increasing interest is being shown in how children develop an understanding of reciprocity in social exchanges and fairness in resource distribution, including social exchanges between third parties. Although there are descriptions of reciprocity on a one-to-one basis in other species, whether nonhumans detect reciprocity and violations of…

  8. Methane Emissions from Leak and Loss Audits of Natural Gas Compressor Stations and Storage Facilities.

    PubMed

    Johnson, Derek R; Covington, April N; Clark, Nigel N

    2015-07-01

    As part of the Environmental Defense Fund's Barnett Coordinated Campaign, researchers completed leak and loss audits for methane emissions at three natural gas compressor stations and two natural gas storage facilities. Researchers employed microdilution high-volume sampling systems in conjunction with in situ methane analyzers, bag samples, and Fourier transform infrared analyzers for emissions rate quantification. All sites had a combined total methane emissions rate of 94.2 kg/h, yet only 12% of the emissions total resulted from leaks. Methane slip from exhausts represented 44% of the total emissions. Remaining methane emissions were attributed to losses from pneumatic actuators and controls, engine crankcases, compressor packing vents, wet seal vents, and slop tanks. Measured values were compared with those reported in literature. Exhaust methane emissions were lower than emissions factor estimates for engine exhausts, but when combined with crankcase emissions, measured values were 11.4% lower than predicted by AP-42 as applicable to emissions factors for four-stroke, lean-burn engines. Average measured wet seal emissions were 3.5 times higher than GRI values but 14 times lower than those reported by Allen et al. Reciprocating compressor packing vent emissions were 39 times higher than values reported by GRI, but about half of values reported by Allen et al. Though the data set was small, researchers have suggested a method to estimate site-wide emissions factors for those powered by four-stroke, lean-burn engines based on fuel consumption and site throughput.

  9. Alternatives to compressor cooling in California climates

    SciTech Connect

    Feustel, H. ); de Almeida, A. . Dept. of Electrical Engineering); Blumstein, C. . Universitywide Energy Research Group)

    1991-01-01

    This review and discussion has been prepared for the California Institute for Energy Efficiency (CIEE) to examine research on alternatives to compressor cooling. The report focuses on strategies for eliminating compressors in California's transition climates -- moderately warm areas located between the cool coastal regions and the hot central regions. Many of these strategies could also help reduce compressor use in hotter climates. Compressor-driven cooling of residences in California's transition climate regions is an undesirable load for California's electric utilities because load factor is poor and usage is typically high during periods of system peak demand. We review a number of alternatives to compressors, including low-energy strategies: evaporative cooling, natural and induced ventilation, reflective coatings, shading with vegetation and improved glazing, thermal storage, and radiative cooling. Also included are two energy-intensive strategies: absorption cooling and desiccant cooling. Our literature survey leads us to conclude that many of these strategies, used either singly or in combination, are technically and economically feasible alternatives to compressor-driven cooling. 78 refs., 8 figs.

  10. RELAP5-3D Compressor Model

    SciTech Connect

    James E. Fisher; Cliff B. Davis; Walter L. Weaver

    2005-06-01

    A compressor model has been implemented in the RELAP5-3D© code. The model is similar to that of the existing pump model, and performs the same function on a gas as the pump performs on a single-phase or two-phase fluid. The compressor component consists of an inlet junction and a control volume, and optionally, an outlet junction. This feature permits cascading compressor components in series. The equations describing the physics of the compressor are derived from first principles. These equations are used to obtain the head, the torque, and the energy dissipation. Compressor performance is specified using a map, specific to the design of the machine, in terms of the ratio of outlet-to-inlet total (or stagnation) pressure and adiabatic efficiency as functions of rotational velocity and flow rate. The input quantities are specified in terms of dimensionless variables, which are corrected to stagnation density and stagnation sound speed. A small correction was formulated for the input of efficiency to account for the error introduced by assumption of constant density when integrating the momentum equation. Comparison of the results of steady-state operation of the compressor model to those of the MIT design calculation showed excellent agreement for both pressure ratio and power.

  11. Core compressor exit stage study, 2

    NASA Technical Reports Server (NTRS)

    Behlke, R. F.; Burdsall, E. A.; Canal, E., Jr.; Korn, N. D.

    1979-01-01

    A total of two three-stage compressors were designed and tested to determine the effects of aspect ratio on compressor performance. The first compressor was designed with an aspect ratio of 0.81; the other, with an aspect ratio of 1.22. Both compressors had a hub-tip ratio of 0.915, representative of the rear stages of a core compressor, and both were designed to achieve a 15.0% surge margin at design pressure ratios of 1.357 and 1.324, respectively, at a mean wheel speed of 167 m/sec. At design speed the 0.81 aspect ratio compressor achieved a pressure ratio of 1.346 at a corrected flow of 4.28 kg/sec and an adiabatic efficiency of 86.1%. The 1.22 aspect ratio design achieved a pressure ratio of 1.314 at 4.35 kg/sec flow and 87.0% adiabatic efficiency. Surge margin to peak efficiency was 24.0% with the lower aspect ratio blading, compared with 12.4% with the higher aspect ratio blading.

  12. The Supersonic Axial-Flow Compressor

    NASA Technical Reports Server (NTRS)

    Kantrowitz, Arthur

    1950-01-01

    An investigation has been made to explore the possibilities of axial-flow compressors operating with supersonic velocities into the blade rows. Preliminary calculations showed that very high pressure ratios across a stage, together with somewhat increased mass flows, were apparently possible with compressors which decelerated air through the speed of sound in their blading. The first phase of the investigation was the development of efficient supersonic diffusers to decelerate air through the speed of sound. The present report is largely a general discussion of some of the essential aerodynamics of single-stage supersonic axial-flow compressors. As an approach to the study of supersonic compressors, three possible velocity diagrams are discussed briefly. Because of the encouraging results of this study, an experimental single-stage supersonic compressor has been constructed and tested in Freon-12. In this compressor, air decelerates through the speed of sound in the rotor blading and enters the stators at subsonic speeds. A pressure ratio of about 1.8 at an efficiency of about 80 percent has been obtained.

  13. PIV measurements of the flow at the inlet of a turbocharger centrifugal compressor with recirculation casing treatment near the inducer

    NASA Astrophysics Data System (ADS)

    Gancedo, Matthieu; Gutmark, Ephraim; Guillou, Erwann

    2016-02-01

    Turbocharging reciprocating engines is a viable solution in order to meet the new regulations for emissions and fuel efficiency in part because turbochargers allow to use smaller, more efficient engines (downsizing) while maintaining power. A major challenge is to match the flow range of a dynamic turbomachine (the centrifugal compressor in the turbocharger) with a positive displacement pump (the engine) as the flow range of the latter is typically higher. The operating range of the compressor is thus of prime interest. At low mass flow rate (MFR), the compressor range is limited by the occurrence of surge. To control and improve it, numerous and varied methods have been used. Yet, an automotive application requires that the solution remains relatively simple and preferably passive. A common feature that has been demonstrated to improve the surge line is the use of flow recirculation in the inducer region through a circumferential bleed slot around the shroud, also called "ported shroud", similar to what has been developed for axial compressors in the past. The compressor studied here features such a device. In order to better understand the effect of the recirculation slot on the compressor functioning, flow measurements were performed at the inlet using particle image velocimetry and the results were correlated with pressure measurements nearby. Measurements were taken on a compressor with and without recirculation and across the full range of normal operation and during surge using a phase-locking method to obtain average flow fields throughout the entire surge cycle. When the recirculation is blocked, it was found that strong backflow develops at low MFR perturbing the incoming flow and inducing significant preswirl. The slot eliminated most of the backflow in front of the inducer making the compressor operation more stable. The measurements performed during surge showed strong backflow occurring periodically during the outlet pressure drop and when the

  14. MTR COMPRESSOR BUILDING, TRA651. RELATED AIR COMPRESSOR EQUIPMENT OUTSIDE BUILDING. ...

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

    MTR COMPRESSOR BUILDING, TRA-651. RELATED AIR COMPRESSOR EQUIPMENT OUTSIDE BUILDING. PIPE LEADS BELOW GRADE INTO MTR BUILDING. CAMERA FACING WEST, IE, EAST SIDE OF MTR BUILDING. INL NEGATIVE NO. 56-1265. Jack L. Larsen, Photographer, 4/20/1956 - Idaho National Engineering Laboratory, Test Reactor Area, Materials & Engineering Test Reactors, Scoville, Butte County, ID

  15. Reliable, Low-Cost, Low-Weight, Non-Hermetic Coating for MCM Applications

    NASA Technical Reports Server (NTRS)

    Jones, Eric W.; Licari, James J.

    2000-01-01

    Through an Air Force Research Laboratory sponsored STM program, reliable, low-cost, low-weight, non-hermetic coatings for multi-chip-module(MCK applications were developed. Using the combination of Sandia Laboratory ATC-01 test chips, AvanTeco's moisture sensor chips(MSC's), and silicon slices, we have shown that organic and organic/inorganic overcoatings are reliable and practical non-hermetic moisture and oxidation barriers. The use of the MSC and unpassivated ATC-01 test chips provided rapid test results and comparison of moisture barrier quality of the overcoatings. The organic coatings studied were Parylene and Cyclotene. The inorganic coatings were Al2O3 and SiO2. The choice of coating(s) is dependent on the environment that the device(s) will be exposed to. We have defined four(4) classes of environments: Class I(moderate temperature/moderate humidity). Class H(high temperature/moderate humidity). Class III(moderate temperature/high humidity). Class IV(high temperature/high humidity). By subjecting the components to adhesion, FTIR, temperature-humidity(TH), pressure cooker(PCT), and electrical tests, we have determined that it is possible to reduce failures 50-70% for organic/inorganic coated components compared to organic coated components. All materials and equipment used are readily available commercially or are standard in most semiconductor fabrication lines. It is estimated that production cost for the developed technology would range from $1-10/module, compared to $20-200 for hermetically sealed packages.

  16. NASA Low-speed Axial Compressor for Fundamental Research

    NASA Technical Reports Server (NTRS)

    Wasserbauer, Charles A.; Weaver, Harold F.; Senyitko, Richard G.

    1995-01-01

    A low-speed multistage axial compressor built by the NASA Lewis Research Center is described. The purpose of this compressor is to increase the understanding of the complex flow phenomena within multistage axial compressors and to obtain detailed data from a multistage compressor environment for use in developing and verifying models for computational fluid dynamic code assessment. The compressor has extensive pressure instrumentation in both stationary and rotating frames of reference, and has provisions for flow visualization and laser velocimetry. The compressor will accommodate rotational speeds to 1050 rpm and is rated at a pressure ratio of 1.042.

  17. Multi-pane glass unit having seal with adhesive and hermetic coating layer

    SciTech Connect

    Miller, Seth A; Stark, David H; Francis, IV, William H; Puligandla, Viswanadham; Boulos, Edward N; Pernicka, John

    2015-02-10

    A vacuum insulated glass unit (VIGU) comprises a first pane of a transparent material and a second pane of a transparent material. The second pane is spaced apart from the first pane to define a cavity therebetween. At least one of a spacer and an array of stand-off members is disposed between the first and second panes to maintain separation therebetween. A first adhesive layer forms at least a portion of a gas-tight connection between the first pane and the second pane. A highly hermetic coating is disposed over the adhesive layer, where the coating is an inorganic layer.

  18. Cooling system for removing metabolic heat from an hermetically sealed spacesuit

    NASA Technical Reports Server (NTRS)

    Webbon, B. W.; Vykukal, H. C.; Williams, B. A. (Inventor)

    1978-01-01

    An improved cooling and ventilating system is described for removing metabolic heat, waste gases and water vapor generated by a wearer of an hermetically sealed spacesuit. The cooling system was characterized by a body suit, having a first circuit for simultaneously establishing a cooling flow of water through the thorax and head sections of the body suit. Circulation patches were included mounted in the thorax section and head section of the body suit. A second circuit for discharing a flow of gas throughout the spacesuit and a disconnect unit for coupling the circuits with a life support system externally related to the spacesuit were provided.

  19. Reciprocal food sharing in the vampire bat

    NASA Astrophysics Data System (ADS)

    Wilkinson, Gerald S.

    1984-03-01

    Behavioural reciprocity can be evolutionarily stable1-3. Initial increase in frequency depends, however, on reciprocal altruists interacting predominantly with other reciprocal altruists either by associating within kin groups or by having sufficient memory to recognize and not aid nonreciprocators. Theory thus suggests that reciprocity should evolve more easily among animals which live in kin groups. Data are available separating reciprocity from nepotism only for unrelated nonhuman animals4. Here, I show that food sharing by regurgitation of blood among wild vampire bats (Desmodus rotundus) depends equally and independently on degree of relatedness and an index of opportunity for recipro cation. That reciprocity operates within groups containing both kin and nonkin is supported further with data on the availability of blood-sharing occasions, estimates of the economics of shar ing blood, and experiments which show that unrelated bats will reciprocally exchange blood in captivity.

  20. Reciprocal uniparental disomy in yeast

    PubMed Central

    Andersen, Sabrina L.; Petes, Thomas D.

    2012-01-01

    In the diploid cells of most organisms, including humans, each chromosome is usually distinguishable from its partner homolog by multiple single-nucleotide polymorphisms. One common type of genetic alteration observed in tumor cells is uniparental disomy (UPD), in which a pair of homologous chromosomes are derived from a single parent, resulting in loss of heterozygosity for all single-nucleotide polymorphisms while maintaining diploidy. Somatic UPD events are usually explained as reflecting two consecutive nondisjunction events. Here we report a previously undescribed mode of chromosome segregation in Saccharomyces cerevisiae in which one cell division produces daughter cells with reciprocal UPD for the same pair of chromosomes without an aneuploid intermediate. One pair of sister chromatids is segregated into one daughter cell and the other pair is segregated into the other daughter cell, mimicking a meiotic chromosome segregation pattern. We term this process “reciprocal uniparental disomy.” PMID:22665764

  1. An Autonomously Reciprocating Transmembrane Nanoactuator.

    PubMed

    Watson, Matthew A; Cockroft, Scott L

    2016-01-22

    Biological molecular machines operate far from equilibrium by coupling chemical potential to repeated cycles of dissipative nanomechanical motion. This principle has been exploited in supramolecular systems that exhibit true machine behavior in solution and on surfaces. However, designed membrane-spanning assemblies developed to date have been limited to simple switches or stochastic shuttles, and true machine behavior has remained elusive. Herein, we present a transmembrane nanoactuator that turns over chemical fuel to drive autonomous reciprocating (back-and-forth) nanomechanical motion. Ratcheted reciprocating motion of a DNA/PEG copolymer threaded through a single α-hemolysin pore was induced by a combination of DNA strand displacement processes and enzyme-catalyzed reactions. Ion-current recordings revealed saw-tooth patterns, indicating that the assemblies operated in autonomous, asymmetric cycles of conformational change at rates of up to one cycle per minute. PMID:26661295

  2. Piston reciprocating compressed air engine

    SciTech Connect

    Cestero, L.G.

    1987-03-24

    A compressed air engine is described comprising: (a). a reservoir of compressed air, (b). two power cylinders each containing a reciprocating piston connected to a crankshaft and flywheel, (c). a transfer cylinder which communicates with each power cylinder and the reservoir, and contains a reciprocating piston connected to the crankshaft, (d). valve means controlled by rotation of the crankshaft for supplying compressed air from the reservoir to each power cylinder and for exhausting compressed air from each power cylinder to the transfer cylinder, (e). valve means controlled by rotation of the crankshaft for supplying from the transfer cylinder to the reservoir compressed air supplied to the transfer cylinder on the exhaust strokes of the pistons of the power cylinders, and (f). an externally powered fan for assisting the exhaust of compressed air from each power cylinder to the transfer cylinder and from there to the compressed air reservoir.

  3. Compressor seal rub energetics study

    NASA Technical Reports Server (NTRS)

    Laverty, W. F.

    1978-01-01

    The rub mechanics of compressor abradable blade tip seals at simulated engine conditions were investigated. Twelve statistically planned, instrumented rub tests were conducted with titanium blades and Feltmetal fibermetal rubstrips. The tests were conducted with single stationary blades rubbing against seal material bonded to rotating test disks. The instantaneous rub torque, speed, incursion rate and blade temperatures were continuously measured and recorded. Basic rub parameters (incursion rate, rub depth, abradable density, blade thickness and rub velocity) were varied to determine the effects on rub energy and heat split between the blade, rubstrip surface and rub debris. The test data was reduced, energies were determined and statistical analyses were completed to determine the primary and interactive effects. Wear surface morphology, profile measurements and metallographic analysis were used to determine wear, glazing, melting and material transfer. The rub energies for these tests were most significantly affected by the incursion rate while rub velocity and blade thickness were of secondary importance. The ratios of blade wear to seal wear were representative of those experienced in engine operation of these seal system materials.

  4. Evolution of cooperation without reciprocity

    NASA Astrophysics Data System (ADS)

    Riolo, Rick L.; Cohen, Michael D.; Axelrod, Robert

    2001-11-01

    A long-standing problem in biological and social sciences is to understand the conditions required for the emergence and maintenance of cooperation in evolving populations. For many situations, kin selection is an adequate explanation, although kin-recognition may still be a problem. Explanations of cooperation between non-kin include continuing interactions that provide a shadow of the future (that is, the expectation of an ongoing relationship) that can sustain reciprocity, possibly supported by mechanisms to bias interactions such as embedding the agents in a two-dimensional space or other context-preserving networks. Another explanation, indirect reciprocity, applies when benevolence to one agent increases the chance of receiving help from others. Here we use computer simulations to show that cooperation can arise when agents donate to others who are sufficiently similar to themselves in some arbitrary characteristic. Such a characteristic, or `tag', can be a marking, display, or other observable trait. Tag-based donation can lead to the emergence of cooperation among agents who have only rudimentary ability to detect environmental signals and, unlike models of direct or indirect reciprocity, no memory of past encounters is required.

  5. Compressor Stall Recovery Through Tip Injection Assessed

    NASA Technical Reports Server (NTRS)

    Suder, Ken L.

    2001-01-01

    Aerodynamic stability is a fundamental limit in the compressor design process. The development of robust techniques for increasing stability has several benefits: enabling higher loading and fewer blades, increasing safety throughout a mission, increasing tolerance to stage mismatch during part-speed operation and speed transients, and providing an opportunity to match stages at the compressor maximum efficiency point, thus reducing fuel burn. Mass injection upstream of the tip of a high-speed axial compressor rotor is a stability enhancement approach known to be effective in suppressing stall in tip-critical rotors if the injection is activated before stall occurs. This approach to stall suppression requires that a reliable stall warning system be available. Tests have recently been performed to assess whether steady injection can also be used to recover from fully developed stall. If mass injection is effective in recovering from stall quickly enough to avoid structural damage or loss of engine power, then a stall warning system may not be required. The stall recovery tests were performed on a transonic compressor rotor at its design tip speed of 1475 ft/sec using four injectors evenly spaced around the compressor case upstream of the rotor. The injectors were connected to an external air source. In an actual engine application, the injected air would be supplied with compressor bleed air. The injectors were isolated from the air source by a fast-acting butterfly valve. With the injectors turned off, the compressor was throttled into stall. Air injection was then activated with no change in throttle setting by opening the butterfly valve. The compressor recovered from stall at a fixed throttle setting with the aid of tip injection. The unsteady operating characteristic of the rotor was measured during these tests using high-response pressure sensors located upstream and downstream of the rotor. The figure shows the results, where the unsteady pressure and mass

  6. Experimental Investigation of Centrifugal Compressor Stabilization Techniques

    NASA Technical Reports Server (NTRS)

    Skoch, Gary J.

    2003-01-01

    Results from a series of experiments to investigate techniques for extending the stable flow range of a centrifugal compressor are reported. The research was conducted in a high-speed centrifugal compressor at the NASA Glenn Research Center. The stabilizing effect of steadily flowing air-streams injected into the vaneless region of a vane-island diffuser through the shroud surface is described. Parametric variations of injection angle, injection flow rate, number of injectors, injector spacing, and injection versus bleed were investigated for a range of impeller speeds and tip clearances. Both the compressor discharge and an external source were used for the injection air supply. The stabilizing effect of flow obstructions created by tubes that were inserted into the diffuser vaneless space through the shroud was also investigated. Tube immersion into the vaneless space was varied in the flow obstruction experiments. Results from testing done at impeller design speed and tip clearance are presented. Surge margin improved by 1.7 points using injection air that was supplied from within the compressor. Externally supplied injection air was used to return the compressor to stable operation after being throttled into surge. The tubes, which were capped to prevent mass flux, provided 9.3 points of additional surge margin over the baseline surge margin of 11.7 points.

  7. A 100-Channel Hermetically Sealed Implantable Device for Chronic Wireless Neurosensing Applications

    PubMed Central

    Yin, Ming; Borton, David A.; Aceros, Juan; Patterson, William R.; Nurmikko, Arto V.

    2014-01-01

    A 100-channel fully implantable wireless broadband neural recording system was developed. It features 100 parallel broadband (0.1 Hz–7.8 kHz) neural recording channels, a medical grade 200 mAh Li-ion battery recharged inductively at 150 kHz, and data telemetry using 3.2 GHz to 3.8 GHz FSK modulated wireless link for 48 Mbps Manchester encoded data. All active electronics are hermetically sealed in a titanium enclosure with a sapphire window for electromagnetic transparency. A custom, high-density configuration of 100 individual hermetic feedthrough pins enable connection to an intracortical neural recording microelectrode array. A 100 MHz bandwidth custom receiver was built to remotely receive the FSK signal and achieved −77.7 dBm sensitivity with 10−8 BER at 48 Mbps data rate. ESD testing on all the electronic inputs and outputs has proven that the implantable device satisfies the HBM Class-1B ESD Standard. In addition, the evaluation of the worst-case charge density delivered to the tissue from each I/O pin verifies the patient safety of the device in the event of failure. Finally, the functionality and reliability of the complete device has been tested on-bench and further validated chronically in ongoing freely moving swine and monkey animal trials for more than one year to date. PMID:23853294

  8. Reliability evaluation of hermetic dual in-line flat microcircuit packages

    NASA Technical Reports Server (NTRS)

    Johnson, G. M.; Conaway, L. K.

    1977-01-01

    The relative strengths and weaknesses of 35 commonly used hermetic flat and dual in-line packages were determined and used to rank each of the packages according to a numerical weighting scheme for package attributes. The list of attributes included desirable features in five major areas: lead and lead seal, body construction, body materials, lid and lid seal, and marking. The metal flat pack and multilayer integral ceramic flat pack and DIP received the highest rankings, and the soft glass Cerdip and Cerpak types received the lowest rankings. Loss of package hermeticity due to lead and lid seal problems was found to be the predominant failure mode from the literature/data search. However, environmental test results showed that lead and lid seal failures due to thermal stressing was only a problem with the hard glass (Ceramic) body DIP utilizing a metal lid and/or bottom. Insufficient failure data were generated for the other package types tested to correlate test results with the package ranking.

  9. Hermetic integration of liquids using high-speed stud bump bonding for cavity sealing at the wafer level

    NASA Astrophysics Data System (ADS)

    Antelius, Mikael; Fischer, Andreas C.; Niklaus, Frank; Stemme, Göran; Roxhed, Niclas

    2012-04-01

    This paper reports a novel room-temperature hermetic liquid sealing process where the access ports of liquid-filled cavities are sealed with wire-bonded stud bumps. This process enables liquids to be integrated at the fabrication stage. Evaluation cavities were manufactured and used to investigate the mechanical and hermetic properties of the seals. Measurements on the successfully sealed structures show a helium leak rate of better than 10-10 mbarL s-1, in addition to a zero liquid loss over two months during storage near boiling temperature. The bond strength of the plugs was similar to standard wire bonds on flat surfaces.

  10. Efficiency study of oil cooling of a screw compressor

    SciTech Connect

    Tree, D.R.; McKellar, M.G.

    1989-04-01

    One of the major goals of all compressor manufacturers is to build as efficient a compressor as possible. Over the last several years improvements to the design of screw compressors has made them efficiently competitive with other types of compressors, especially at large loads. The primary purpose of this research is to investigate four different methods of cooling a 250 horsepower compressor and determine their effects on the efficiency of the compressor. Two conventional methods, liquid injection and thermosyphon cooling, and two new methods, V-PLUS and Fresco oil injection, are investigated. The screw compressor used in the tests was a VRS-500 screw compressor made by the Vilter Manufacturing Corporation. 6 figs.

  11. 40 CFR 204.57-3 - Test compressor preparation.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... fixtures necessary to conduct the test may be installed on the compressor: Provided, That such equipment of fixtures shall have no effect on the noise emissions of the compressor, as determined by the...

  12. 40 CFR 204.57-3 - Test compressor preparation.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... fixtures necessary to conduct the test may be installed on the compressor: Provided, That such equipment of fixtures shall have no effect on the noise emissions of the compressor, as determined by the...

  13. 49 CFR 192.165 - Compressor stations: Liquid removal.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... HAZARDOUS MATERIALS SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) PIPELINE SAFETY... the anticipated pressure and temperature conditions, the compressor must be protected against the... facilities, an automatic compressor shutdown device, or a high liquid level alarm; and (3) Be manufactured...

  14. Imperfect information facilitates the evolution of reciprocity.

    PubMed

    Kurokawa, Shun

    2016-06-01

    The existence of cooperation demands explanation since cooperation is costly to the actor. Reciprocity has long been regarded as a potential explanatory mechanism for the existence of cooperation. Reciprocity is a mechanism wherein a cooperator responds to an opponent's behavior by switching his/her own behavior. Hence, a possible problematic case relevant to the theory of reciprocity evolution arises when the mechanism is such that the information regarding an opponent's behavior is imperfect. Although it has been confirmed also by previous theoretical studies that imperfect information interferes with the evolution of reciprocity, this argument is based on the assumption that there are no mistakes in behavior. And, a previous study presumed that it might be expected that when such mistakes occur, reciprocity can more readily evolve in the case of imperfect information than in the case of perfect information. The reason why the previous study considers so is that in the former case, reciprocators can miss defections incurred by other reciprocators' mistakes due to imperfect information, allowing cooperation to persist when such reciprocators meet. However, contrary to this expectation, the previous study has shown that even when mistakes occur, imperfect information interferes with the evolution of reciprocity. Nevertheless, the previous study assumed that payoffs are linear (i.e., that the effect of behavior is additive and there are no synergetic effects). In this study, we revisited the same problem but removed the assumption that payoffs are linear. We used evolutionarily stable strategy analysis to compare the condition for reciprocity to evolve when mistakes occur and information is imperfect with the condition for reciprocity to evolve when mistakes occur and information is perfect. Our study revealed that when payoffs are not linear, imperfect information can facilitate the evolution of reciprocity when mistakes occur; while when payoffs are linear

  15. Novel Compressor Blade Design Study

    NASA Astrophysics Data System (ADS)

    Srinivas, Abhay

    Jet engine efficiency goals are driving compressors to higher pressure ratios and engines to higher bypass ratios, each one driving to smaller cores. This is leading to larger tip gaps relative to the blade height. These larger relative tip clearances would negate some of the cycle improvements, and ways to mitigate this effect must be found. A novel split tip blade geometry has been created which helps improve the efficiency at large clearances while also improving operating range. Two identical blades are leaned in opposite directions starting at 85% span. They are cut at mid chord and the 2 halves then merged together so a split tip is created. The result is similar to the alula feathers on a soaring bird. The concept is that the split tip will energize the tip flow and increase range. For higher relative tip clearance, this will also improve efficiency. The 6th rotor of a highly loaded 10 stage machine was chosen as the baseline for this study. Three dimensional CFD simulations were performed using CD Adapco's Star-CCM+ at 5 clearances for the baseline and split tip geometry. The choking flow and stall margin of the split tip blade was higher than that of the baseline blade for all tip clearances. The pressure ratio of the novel blade was higher than that of the baseline blade near choke, but closer to stall it decreased. The sensitivity of peak efficiency to clearance was improved. At tight clearances of 0.62% of blade height, the maximum efficiency of the new design was less than the baseline blade, but as the tip clearance was increased above 2.5%, the maximum efficiency increased. Structural analysis was also performed to ascertain the feasibility of the design.

  16. High pressure compressor component performance report

    NASA Technical Reports Server (NTRS)

    Cline, S. J.; Fesler, W.; Liu, H. S.; Lovell, R. C.; Shaffer, S. J.

    1983-01-01

    A compressor optimization study defined a 10 stage configuration with a 22.6:1 pressure ratio, an adiabatic efficiency goal of 86.1%, and a polytropic efficiency of 90.6%; the corrected airflow is 53.5 kg/s. Subsequent component testing included three full scale tests: a six stage rig test, a 10 stage rig test, and another 10 stage rig test completed in the second quarter of 1982. Information from these tests is used to select the configuration for a core engine test and an integrated core/low spool test. The test results will also provide data base for the flight propulsion system. The results of the test series with both aerodynamic and mechanical performance of each compressor build are presented. The second 10 stage compressor adiabatic efficiency was 0.848 at a cruise operating point versus a test goal of 0.846.

  17. Sorption compressor/mechanical expander hybrid refrigeration

    NASA Technical Reports Server (NTRS)

    Jones, J. A.; Britcliffe, M.

    1987-01-01

    Experience with Deep Space Network (DSN) ground-based cryogenic refrigerators has proved the reliability of the basic two-stage Gifford-McMahon helium refrigerator. A very long life cryogenic refrigeration system appears possible by combining this expansion system or a turbo expansion system with a hydride sorption compressor in place of the usual motor driven piston compressor. To test the feasibility of this system, a commercial Gifford-McMahon refrigerator was tested using hydrogen gas as the working fluid. Although no attempt was made to optimize the system for hydrogen operation, the refrigerator developed 1.3 W at 30 K and 6.6 W at 60 K. The results of the test and of theoretical performances of the hybrid compressor coupled to these expansion systems are presented.

  18. Compressor airfoil tip clearance optimization system

    DOEpatents

    Little, David A.; Pu, Zhengxiang

    2015-08-18

    A compressor airfoil tip clearance optimization system for reducing a gap between a tip of a compressor airfoil and a radially adjacent component of a turbine engine is disclosed. The turbine engine may include ID and OD flowpath boundaries configured to minimize compressor airfoil tip clearances during turbine engine operation in cooperation with one or more clearance reduction systems that are configured to move the rotor assembly axially to reduce tip clearance. The configurations of the ID and OD flowpath boundaries enhance the effectiveness of the axial movement of the rotor assembly, which includes movement of the ID flowpath boundary. During operation of the turbine engine, the rotor assembly may be moved axially to increase the efficiency of the turbine engine.

  19. Interconnecting compressors control coalbed gas production

    SciTech Connect

    Payton, R.; Niederhofer, J. )

    1992-10-05

    This paper reports that centralized compressors afford Taurus Exploration Inc.'s coalbed gas operations optimum control of gas production. Unlike satellite stations, the centralized system allows methane gas to e shifted from station to station via the interconnecting low-pressure pipeline network. The operations area encompasses approximately 40,000 acres, about 40 miles southwest of Birmingham, Ala. The project includes about 250-miles of low-pressure gas flow lines to almost 400 wells. The centralized system is less costly than a satellite station to build and operate. Unlike a satellite station that requires each compressor to have a complete set of ancillary equipment, the centralized system requires only one suction manifold, one dehydration setup, and one metering facility for every five compressor sets.

  20. 49 CFR 192.169 - Compressor stations: Pressure limiting devices.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 3 2013-10-01 2013-10-01 false Compressor stations: Pressure limiting devices... Pipeline Components § 192.169 Compressor stations: Pressure limiting devices. (a) Each compressor station must have pressure relief or other suitable protective devices of sufficient capacity and...

  1. 40 CFR 204.57-2 - Test compressor sample selection.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Test compressor sample selection. (a) Compressors comprising the batch sample which are required to be tested pursuant to a test request in accordance with this subpart will be randomly selected from a batch... will be achieved by sequentially numbering all of the compressors in the batch and then using a...

  2. 40 CFR 204.57-2 - Test compressor sample selection.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Test compressor sample selection. (a) Compressors comprising the batch sample which are required to be tested pursuant to a test request in accordance with this subpart will be randomly selected from a batch... will be achieved by sequentially numbering all of the compressors in the batch and then using a...

  3. 40 CFR 204.57-2 - Test compressor sample selection.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... Test compressor sample selection. (a) Compressors comprising the batch sample which are required to be tested pursuant to a test request in accordance with this subpart will be randomly selected from a batch... will be achieved by sequentially numbering all of the compressors in the batch and then using a...

  4. 40 CFR 204.57-2 - Test compressor sample selection.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... Test compressor sample selection. (a) Compressors comprising the batch sample which are required to be tested pursuant to a test request in accordance with this subpart will be randomly selected from a batch... will be achieved by sequentially numbering all of the compressors in the batch and then using a...

  5. 40 CFR 204.57-2 - Test compressor sample selection.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... Test compressor sample selection. (a) Compressors comprising the batch sample which are required to be tested pursuant to a test request in accordance with this subpart will be randomly selected from a batch... will be achieved by sequentially numbering all of the compressors in the batch and then using a...

  6. 30 CFR 56.13012 - Compressor air intakes.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Compressor air intakes. 56.13012 Section 56... MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-SURFACE METAL AND NONMETAL MINES Compressed Air and Boilers § 56.13012 Compressor air intakes. Compressor air intakes shall be installed to ensure that...

  7. 21 CFR 868.6250 - Portable air compressor.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Portable air compressor. 868.6250 Section 868.6250...) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Miscellaneous § 868.6250 Portable air compressor. (a) Identification. A portable air compressor is a device intended to provide compressed air for medical purposes,...

  8. 30 CFR 57.13012 - Compressor air intakes.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Compressor air intakes. 57.13012 Section 57... MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-UNDERGROUND METAL AND NONMETAL MINES Compressed Air and Boilers § 57.13012 Compressor air intakes. Compressor air intakes shall be installed to...

  9. 46 CFR 197.310 - Air compressor system.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 7 2012-10-01 2012-10-01 false Air compressor system. 197.310 Section 197.310 Shipping... GENERAL PROVISIONS Commercial Diving Operations Equipment § 197.310 Air compressor system. A compressor used to supply breathing air to a diver must have— (a) A volume tank that is— (1) Built and stamped...

  10. 30 CFR 56.13012 - Compressor air intakes.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Compressor air intakes. 56.13012 Section 56... MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-SURFACE METAL AND NONMETAL MINES Compressed Air and Boilers § 56.13012 Compressor air intakes. Compressor air intakes shall be installed to ensure that...

  11. 21 CFR 868.6250 - Portable air compressor.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Portable air compressor. 868.6250 Section 868.6250...) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Miscellaneous § 868.6250 Portable air compressor. (a) Identification. A portable air compressor is a device intended to provide compressed air for medical purposes,...

  12. 30 CFR 56.13012 - Compressor air intakes.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Compressor air intakes. 56.13012 Section 56... MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-SURFACE METAL AND NONMETAL MINES Compressed Air and Boilers § 56.13012 Compressor air intakes. Compressor air intakes shall be installed to ensure that...

  13. 30 CFR 56.13017 - Compressor discharge pipes.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Compressor discharge pipes. 56.13017 Section 56.13017 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL... Boilers § 56.13017 Compressor discharge pipes. Compressor discharge pipes where carbon build-up may...

  14. 30 CFR 56.13017 - Compressor discharge pipes.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Compressor discharge pipes. 56.13017 Section 56.13017 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL... Boilers § 56.13017 Compressor discharge pipes. Compressor discharge pipes where carbon build-up may...

  15. 30 CFR 57.13017 - Compressor discharge pipes.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Compressor discharge pipes. 57.13017 Section 57.13017 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL... and Boilers § 57.13017 Compressor discharge pipes. Compressor discharge pipes where carbon...

  16. 30 CFR 57.13017 - Compressor discharge pipes.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Compressor discharge pipes. 57.13017 Section 57.13017 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL... and Boilers § 57.13017 Compressor discharge pipes. Compressor discharge pipes where carbon...

  17. 30 CFR 57.13017 - Compressor discharge pipes.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Compressor discharge pipes. 57.13017 Section 57.13017 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL... and Boilers § 57.13017 Compressor discharge pipes. Compressor discharge pipes where carbon...

  18. 30 CFR 56.13017 - Compressor discharge pipes.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Compressor discharge pipes. 56.13017 Section 56.13017 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL... Boilers § 56.13017 Compressor discharge pipes. Compressor discharge pipes where carbon build-up may...

  19. Advanced Compressor Designs for High Energy Petawatt Pulse Generation

    SciTech Connect

    Fittinghoff, D N; Wattellier, B; Barty, C P J

    2003-09-09

    We discuss compressor designs for a proposed multikilojoule, sub-picosecond beamline at the National Ignition Facility. A novel grating configuration reduces the size of the compressor chamber. Optimization of the design leads to a 4.7 x 1.4 x 0.4 m{sup 3} minimum compressor volume.

  20. 49 CFR 192.167 - Compressor stations: Emergency shutdown.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... events: (1) In the case of an unattended compressor station: (i) When the gas pressure equals the maximum... (2) In the case of a compressor station in a building: (i) When an uncontrolled fire occurs in the... 49 Transportation 3 2012-10-01 2012-10-01 false Compressor stations: Emergency shutdown....

  1. 49 CFR 192.167 - Compressor stations: Emergency shutdown.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... events: (1) In the case of an unattended compressor station: (i) When the gas pressure equals the maximum... (2) In the case of a compressor station in a building: (i) When an uncontrolled fire occurs in the... 49 Transportation 3 2011-10-01 2011-10-01 false Compressor stations: Emergency shutdown....

  2. 49 CFR 192.167 - Compressor stations: Emergency shutdown.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... events: (1) In the case of an unattended compressor station: (i) When the gas pressure equals the maximum... (2) In the case of a compressor station in a building: (i) When an uncontrolled fire occurs in the... 49 Transportation 3 2014-10-01 2014-10-01 false Compressor stations: Emergency shutdown....

  3. 49 CFR 192.167 - Compressor stations: Emergency shutdown.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... events: (1) In the case of an unattended compressor station: (i) When the gas pressure equals the maximum... (2) In the case of a compressor station in a building: (i) When an uncontrolled fire occurs in the... 49 Transportation 3 2013-10-01 2013-10-01 false Compressor stations: Emergency shutdown....

  4. 49 CFR 192.167 - Compressor stations: Emergency shutdown.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... events: (1) In the case of an unattended compressor station: (i) When the gas pressure equals the maximum... (2) In the case of a compressor station in a building: (i) When an uncontrolled fire occurs in the... 49 Transportation 3 2010-10-01 2010-10-01 false Compressor stations: Emergency shutdown....

  5. 49 CFR 192.736 - Compressor stations: Gas detection.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 3 2014-10-01 2014-10-01 false Compressor stations: Gas detection. 192.736... TRANSPORTATION OF NATURAL AND OTHER GAS BY PIPELINE: MINIMUM FEDERAL SAFETY STANDARDS Maintenance § 192.736 Compressor stations: Gas detection. (a) Not later than September 16, 1996, each compressor building in...

  6. 49 CFR 192.736 - Compressor stations: Gas detection.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 3 2010-10-01 2010-10-01 false Compressor stations: Gas detection. 192.736... TRANSPORTATION OF NATURAL AND OTHER GAS BY PIPELINE: MINIMUM FEDERAL SAFETY STANDARDS Maintenance § 192.736 Compressor stations: Gas detection. (a) Not later than September 16, 1996, each compressor building in...

  7. 49 CFR 192.736 - Compressor stations: Gas detection.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 3 2012-10-01 2012-10-01 false Compressor stations: Gas detection. 192.736... TRANSPORTATION OF NATURAL AND OTHER GAS BY PIPELINE: MINIMUM FEDERAL SAFETY STANDARDS Maintenance § 192.736 Compressor stations: Gas detection. (a) Not later than September 16, 1996, each compressor building in...

  8. 49 CFR 192.165 - Compressor stations: Liquid removal.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 3 2013-10-01 2013-10-01 false Compressor stations: Liquid removal. 192.165... Components § 192.165 Compressor stations: Liquid removal. (a) Where entrained vapors in gas may liquefy under the anticipated pressure and temperature conditions, the compressor must be protected against...

  9. 21 CFR 868.6250 - Portable air compressor.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Portable air compressor. 868.6250 Section 868.6250...) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Miscellaneous § 868.6250 Portable air compressor. (a) Identification. A portable air compressor is a device intended to provide compressed air for medical purposes,...

  10. 46 CFR 197.310 - Air compressor system.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Air compressor system. 197.310 Section 197.310 Shipping... GENERAL PROVISIONS Commercial Diving Operations Equipment § 197.310 Air compressor system. A compressor used to supply breathing air to a diver must have— (a) A volume tank that is— (1) Built and stamped...

  11. 49 CFR 178.337-15 - Pumps and compressors.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Pumps and compressors. 178.337-15 Section 178.337... PACKAGINGS Specifications for Containers for Motor Vehicle Transportation § 178.337-15 Pumps and compressors. (a) Liquid pumps or gas compressors, if used, must be of suitable design, adequately...

  12. 49 CFR 178.337-15 - Pumps and compressors.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 3 2014-10-01 2014-10-01 false Pumps and compressors. 178.337-15 Section 178.337... Specifications for Containers for Motor Vehicle Transportation § 178.337-15 Pumps and compressors. (a) Liquid pumps or gas compressors, if used, must be of suitable design, adequately protected against breakage...

  13. 49 CFR 178.337-15 - Pumps and compressors.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 3 2012-10-01 2012-10-01 false Pumps and compressors. 178.337-15 Section 178.337... Specifications for Containers for Motor Vehicle Transportation § 178.337-15 Pumps and compressors. (a) Liquid pumps or gas compressors, if used, must be of suitable design, adequately protected against breakage...

  14. 49 CFR 192.173 - Compressor stations: Ventilation.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 3 2010-10-01 2010-10-01 false Compressor stations: Ventilation. 192.173 Section... NATURAL AND OTHER GAS BY PIPELINE: MINIMUM FEDERAL SAFETY STANDARDS Design of Pipeline Components § 192.173 Compressor stations: Ventilation. Each compressor station building must be ventilated to...

  15. 49 CFR 192.171 - Compressor stations: Additional safety equipment.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... event of inadequate cooling or lubrication of the unit. (d) Each compressor station gas engine that... compressor station must have vent slots or holes in the baffles of each compartment to prevent gas from being... 49 Transportation 3 2010-10-01 2010-10-01 false Compressor stations: Additional safety...

  16. 49 CFR 192.173 - Compressor stations: Ventilation.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 3 2011-10-01 2011-10-01 false Compressor stations: Ventilation. 192.173 Section... NATURAL AND OTHER GAS BY PIPELINE: MINIMUM FEDERAL SAFETY STANDARDS Design of Pipeline Components § 192.173 Compressor stations: Ventilation. Each compressor station building must be ventilated to...

  17. 49 CFR 192.171 - Compressor stations: Additional safety equipment.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... event of inadequate cooling or lubrication of the unit. (d) Each compressor station gas engine that... compressor station must have vent slots or holes in the baffles of each compartment to prevent gas from being... 49 Transportation 3 2011-10-01 2011-10-01 false Compressor stations: Additional safety...

  18. Cold Climate Heat Pumps Using Tandem Compressors

    SciTech Connect

    Shen, Bo; Abdelaziz, Omar; Rice, C Keith; Baxter, Van D

    2016-01-01

    In cold climate zones, e.g. ASHRAE climate regions IV and V, conventional electric air-source heat pumps (ASHP) do not work well, due to high compressor discharge temperatures, large pressure ratios and inadequate heating capacities at low ambient temperatures. Consequently, significant use of auxiliary strip heating is required to meet the building heating load. We introduce innovative ASHP technologies as part of continuing efforts to eliminate auxiliary strip heat use and maximize heating COP with acceptable cost-effectiveness and reliability. These innovative ASHP were developed using tandem compressors, which are capable of augmenting heating capacity at low temperatures and maintain superior part-load operation efficiency at moderate temperatures. Two options of tandem compressors were studied; the first employs two identical, single-speed compressors, and the second employs two identical, vapor-injection compressors. The investigations were based on system modeling and laboratory evaluation. Both designs have successfully met the performance criteria. Laboratory evaluation showed that the tandem, single-speed compressor ASHP system is able to achieve heating COP = 4.2 at 47 F (8.3 C), COP = 2.9 at 17 F (-8.3 C), and 76% rated capacity and COP = 1.9 at -13 F (-25 C). This yields a HSPF = 11.0 (per AHRI 210/240). The tandem, vapor-injection ASHP is able to reach heating COP = 4.4 at 47 F, COP = 3.1 at 17 F, and 88% rated capacity and COP = 2.0 at -13 F. This yields a HSPF = 12.0. The system modeling and further laboratory evaluation are presented in the paper.

  19. Method and apparatus for starting supersonic compressors

    SciTech Connect

    Lawlor, Shawn P.

    2012-04-10

    A supersonic gas compressor. The compressor includes aerodynamic duct(s) situated on a rotor journaled in a casing. The aerodynamic duct(s) generate a plurality of oblique shock waves for efficiently compressing a gas at supersonic conditions. The convergent inlet is adjacent to a bleed air collector, and during acceleration of the rotor, bypass gas is removed from the convergent inlet via a collector to enable supersonic shock stabilization. Once the oblique shocks are stabilized at a selected inlet relative Mach number and pressure ratio, the bleed of bypass gas from the convergent inlet via the bypass gas collectors is eliminated.

  20. Active magnetic bearings applied to industrial compressors

    NASA Technical Reports Server (NTRS)

    Kirk, R. G.; Hustak, J. F.; Schoeneck, K. A.

    1993-01-01

    The design and shop test results are given for a high-speed eight-stage centrifugal compressor supported by active magnetic bearings. A brief summary of the basic operation of active magnetic bearings and the required rotor dynamics analysis are presented with specific attention given to design considerations for optimum rotor stability. The concerns for retrofits of magnetic bearings in existing machinery are discussed with supporting analysis of a four-stage centrifugal compressor. The current status of industrial machinery in North America using this new support system is presented and recommendations are given on design and analysis requirements for successful machinery operation of either retrofit or new design turbomachinery.

  1. Alignment of chirped-pulse compressor

    SciTech Connect

    Yakovlev, I V

    2012-11-30

    An original method of alignment of grating compressors for ultrahigh-power CPA laser systems is proposed. The use of this method for adjustment of the grating compressor of a PEARL subpetawatt laser complex made it possible to align the diffraction gratings with a second accuracy in all three angular degrees of freedom, including alignment of the grooves, and to adjust the angles of beam incidence on the grating with a high accuracy. A simple method for measuring the difference in the groove densities of gratings with accuracy better than 0.005 lines mm{sup -1} is proposed and tested. (control of laser radiation parameters)

  2. Directional excitation without breaking reciprocity

    NASA Astrophysics Data System (ADS)

    Ramezani, Hamidreza; Dubois, Marc; Wang, Yuan; Shen, Y. Ron; Zhang, Xiang

    2016-09-01

    We propose a mechanism for directional excitation without breaking reciprocity. This is achieved by embedding an impedance matched parity-time symmetric potential in a three-port system. The amplitude distribution within the gain and loss regions is strongly influenced by the direction of the incoming field. Consequently, the excitation of the third port is contingent on the direction of incidence while transmission in the main channel is immune. Our design improves the four-port directional coupler scheme, as there is no need to implement an anechoic termination to one of the ports.

  3. Towards a unified theory of reciprocity.

    PubMed

    Rosas, Alejandro

    2012-02-01

    In a unified theory of human reciprocity, the strong and weak forms are similar because neither is biologically altruistic and both require normative motivation to support cooperation. However, strong reciprocity is necessary to support cooperation in public goods games. It involves inflicting costs on defectors; and though the costs for punishers are recouped, recouping costs requires complex institutions that would not have emerged if weak reciprocity had been enough.

  4. Reciprocating motion of active deformable particles

    NASA Astrophysics Data System (ADS)

    Tarama, M.; Ohta, T.

    2016-05-01

    Reciprocating motion of an active deformable particle in a homogeneous medium is studied theoretically. For generality, we employ a simple model derived from symmetry considerations for the center-of-mass velocity and elliptical and triangular deformations in two dimensions. We carry out, for the first time, a systematic investigation of the reciprocating motion of a self-propelled particle. It is clarified that spontaneous breaking of the front-rear asymmetry is essential for the reciprocating motion. Moreover, two routes are found for the formation of the reciprocating motion. One is a bifurcation from a motionless stationary state. The other is destabilisation of an oscillatory rectilinear motion.

  5. Evolution of spite through indirect reciprocity.

    PubMed Central

    Johnstone, Rufus A.; Bshary, Redouan

    2004-01-01

    How can cooperation persist in the face of a temptation to 'cheat'? Several recent papers have suggested that the answer may lie in indirect reciprocity. Altruistic individuals may benefit by eliciting altruism from observers, rather than (as in direct reciprocity) from the recipient of the aid they provide. Here, we point out that indirect reciprocity need not always favour cooperation; by contrast, it may support spiteful behaviour, which is costly for the both actor and recipient. Existing theory suggests spite is unlikely to persist, but we demonstrate that it may do so when spiteful individuals are less likely to incur aggression from observers (a negative form of indirect reciprocity). PMID:15347514

  6. Application of Au-Sn eutectic bonding in hermetic radio-frequency microelectromechanical system wafer level packaging

    NASA Astrophysics Data System (ADS)

    Wang, Qian; Choa, Sung-Hoon; Kim, Woonbae; Hwang, Junsik; Ham, Sukjin; Moon, Changyoul

    2006-03-01

    Development of packaging is one of the critical issues toward realizing commercialization of radio-frequency-microelectromechanical system (RF-MEMS) devices. The RF-MEMS package should be designed to have small size, hermetic protection, good RF performance, and high reliability. In addition, packaging should be conducted at sufficiently low temperature. In this paper, a low-temperature hermetic wafer level packaging scheme for the RF-MEMS devices is presented. For hermetic sealing, Au-Sn eutectic bonding technology at temperatures below 300°C is used. Au-Sn multilayer metallization with a square loop of 70 µm in width is performed. The electrical feed-through is achieved by the vertical through-hole via filling with electroplated Cu. The size of the MEMS package is 1 mm × 1 mm × 700 µm. The shear strength and hermeticity of the package satisfies the requirements of MIL-STD-883F. Any organic gases or contamination are not observed inside the package. The total insertion loss for the packaging is 0.075 dB at 2 GHz. Furthermore, the robustness of the package is demonstrated by observing no performance degradation and physical damage of the package after several reliability tests.

  7. 9 CFR 355.25 - Canning with heat processing and hermetically sealed containers; closures; code marking; heat...

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 9 Animals and Animal Products 2 2014-01-01 2014-01-01 false Canning with heat processing and hermetically sealed containers; closures; code marking; heat processing; incubation. 355.25 Section 355.25... IDENTIFICATION AS TO CLASS, QUALITY, QUANTITY, AND CONDITION Inspection Procedure § 355.25 Canning with...

  8. 9 CFR 355.25 - Canning with heat processing and hermetically sealed containers; closures; code marking; heat...

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 9 Animals and Animal Products 2 2013-01-01 2013-01-01 false Canning with heat processing and hermetically sealed containers; closures; code marking; heat processing; incubation. 355.25 Section 355.25... IDENTIFICATION AS TO CLASS, QUALITY, QUANTITY, AND CONDITION Inspection Procedure § 355.25 Canning with...

  9. 9 CFR 355.25 - Canning with heat processing and hermetically sealed containers; closures; code marking; heat...

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 9 Animals and Animal Products 2 2011-01-01 2011-01-01 false Canning with heat processing and hermetically sealed containers; closures; code marking; heat processing; incubation. 355.25 Section 355.25... IDENTIFICATION AS TO CLASS, QUALITY, QUANTITY, AND CONDITION Inspection Procedure § 355.25 Canning with...

  10. 9 CFR 355.25 - Canning with heat processing and hermetically sealed containers; closures; code marking; heat...

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 9 Animals and Animal Products 2 2010-01-01 2010-01-01 false Canning with heat processing and hermetically sealed containers; closures; code marking; heat processing; incubation. 355.25 Section 355.25... IDENTIFICATION AS TO CLASS, QUALITY, QUANTITY, AND CONDITION Inspection Procedure § 355.25 Canning with...

  11. 9 CFR 355.25 - Canning with heat processing and hermetically sealed containers; closures; code marking; heat...

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 9 Animals and Animal Products 2 2012-01-01 2012-01-01 false Canning with heat processing and hermetically sealed containers; closures; code marking; heat processing; incubation. 355.25 Section 355.25... IDENTIFICATION AS TO CLASS, QUALITY, QUANTITY, AND CONDITION Inspection Procedure § 355.25 Canning with...

  12. 21 CFR 108.35 - Thermal processing of low-acid foods packaged in hermetically sealed containers.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... manufacture, processing, or packing of thermally processed low-acid foods in hermetically sealed containers may result in the distribution in interstate commerce of processed foods that may be injurious to... engaged in the manufacture, processing, or packing of thermally processed low-acid foods in...

  13. 21 CFR 108.35 - Thermal processing of low-acid foods packaged in hermetically sealed containers.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... sealed containers shall promptly report to the Food and Drug Administration any instance of spoilage or... 21 Food and Drugs 2 2012-04-01 2012-04-01 false Thermal processing of low-acid foods packaged in hermetically sealed containers. 108.35 Section 108.35 Food and Drugs FOOD AND DRUG ADMINISTRATION,...

  14. 21 CFR 108.35 - Thermal processing of low-acid foods packaged in hermetically sealed containers.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... sealed containers shall promptly report to the Food and Drug Administration any instance of spoilage or... 21 Food and Drugs 2 2011-04-01 2011-04-01 false Thermal processing of low-acid foods packaged in hermetically sealed containers. 108.35 Section 108.35 Food and Drugs FOOD AND DRUG ADMINISTRATION,...

  15. 21 CFR 108.35 - Thermal processing of low-acid foods packaged in hermetically sealed containers.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... sealed containers shall promptly report to the Food and Drug Administration any instance of spoilage or... 21 Food and Drugs 2 2014-04-01 2014-04-01 false Thermal processing of low-acid foods packaged in hermetically sealed containers. 108.35 Section 108.35 Food and Drugs FOOD AND DRUG ADMINISTRATION,...

  16. A method for wafer level hermetic packaging of SOI-MEMS devices with embedded vertical feedthroughs using advanced MEMS process

    NASA Astrophysics Data System (ADS)

    Mert Torunbalci, Mustafa; Emre Alper, Said; Akin, Tayfun

    2015-12-01

    This paper presents a novel, inherently simple, and low-cost fabrication and hermetic packaging method developed for SOI-MEMS devices, where a single SOI wafer is used for the fabrication of MEMS structures as well as vertical feedthroughs, while a single glass cap wafer is used for hermetic encapsulation and routing metallization. Hermetic encapsulation can be achieved either with the silicon-glass anodic or Au-Si eutectic bonding techniques. The dies sealed with anodic and Au-Si eutectic bonding provide a low vertical feedthrough resistance around 50 Ω. Glass-to-silicon anodically and Au-Si eutectic bonded seals yield a very stable cavity pressure below 10 mTorr with thin-film getters, which are measured to be stable even after 311 d. The package pressure can be adjusted from 5 mTorr to 20 Torr by using different outgassing, cavity depth, and gettering options. The packaging yield is observed to be around 64% and 84% for the anodic and Au-Si eutectic packages, respectively. The average shear strength of the anodic and eutectic packages is measured to be higher than 17 MPa and 42 MPa, respectively. Temperature cycling, high temperature storage, and ultra-high temperature shock tests result in no degradation in the hermeticity of the packaged chips, proving perfect thermal reliability.

  17. Indirect reciprocity with trinary reputations.

    PubMed

    Tanabe, Shoma; Suzuki, Hideyuki; Masuda, Naoki

    2013-01-21

    Indirect reciprocity is a reputation-based mechanism for cooperation in social dilemma situations when individuals do not repeatedly meet. The conditions under which cooperation based on indirect reciprocity occurs have been examined in great details. Most previous theoretical analysis assumed for mathematical tractability that an individual possesses a binary reputation value, i.e., good or bad, which depends on their past actions and other factors. However, in real situations, reputations of individuals may be multiple valued. Another puzzling discrepancy between the theory and experiments is the status of the so-called image scoring, in which cooperation and defection are judged to be good and bad, respectively, independent of other factors. Such an assessment rule is found in behavioral experiments, whereas it is known to be unstable in theory. In the present study, we fill both gaps by analyzing a trinary reputation model. By an exhaustive search, we identify all the cooperative and stable equilibria composed of a homogeneous population or a heterogeneous population containing two types of players. Some results derived for the trinary reputation model are direct extensions of those for the binary model. However, we find that the trinary model allows cooperation under image scoring under some mild conditions.

  18. Indirect reciprocity with trinary reputations.

    PubMed

    Tanabe, Shoma; Suzuki, Hideyuki; Masuda, Naoki

    2013-01-21

    Indirect reciprocity is a reputation-based mechanism for cooperation in social dilemma situations when individuals do not repeatedly meet. The conditions under which cooperation based on indirect reciprocity occurs have been examined in great details. Most previous theoretical analysis assumed for mathematical tractability that an individual possesses a binary reputation value, i.e., good or bad, which depends on their past actions and other factors. However, in real situations, reputations of individuals may be multiple valued. Another puzzling discrepancy between the theory and experiments is the status of the so-called image scoring, in which cooperation and defection are judged to be good and bad, respectively, independent of other factors. Such an assessment rule is found in behavioral experiments, whereas it is known to be unstable in theory. In the present study, we fill both gaps by analyzing a trinary reputation model. By an exhaustive search, we identify all the cooperative and stable equilibria composed of a homogeneous population or a heterogeneous population containing two types of players. Some results derived for the trinary reputation model are direct extensions of those for the binary model. However, we find that the trinary model allows cooperation under image scoring under some mild conditions. PMID:23123557

  19. Development of a J-T Micro Compressor

    NASA Astrophysics Data System (ADS)

    Champagne, P.; Olson, J. R.; Nast, T.; Roth, E.; Collaco, A.; Kaldas, G.; Saito, E.; Loung, V.

    2015-12-01

    Lockheed Martin has developed and tested a space-quality compressor capable of delivering closed-loop gas flow with a high pressure ratio, suitable for driving a Joule- Thomson cold head. The compressor is based on a traditional “Oxford style” dual-opposed piston compressor with linear drive motors and flexure-bearing clearance-seal technology for high reliability and long life. This J-T compressor retains the approximate size, weight, and cost of the ultra-compact, 200 gram Lockheed Martin Pulse Tube Micro Compressor, despite the addition of a flow-rectifying system to convert the AC pressure wave into a steady flow.

  20. 30 CFR 75.344 - Compressors.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... air course or to the surface and equipped with sensors to monitor for heat and for carbon monoxide or smoke. The sensors shall deenergize power to the compressor, activate a visual and audible alarm located... every 31 days, sensors installed to monitor for carbon monoxide shall be calibrated with a...

  1. Experimental study on performance of BOG compressor

    NASA Astrophysics Data System (ADS)

    Zhao, Bin; Wang, Tao; Peng, Xueyuan; Feng, Jianmei

    2015-08-01

    The boil-off gas (BOG) compressor is widely used for recycling the excessive boil-off gas of liquefied natural gas (LNG), and the extra-low suction temperature brings about great challenges to design of the BOG compressor. In this paper, a test system was built to examine the effects of low suction temperature on the compressor performance, in which the lowest temperature reached -178°C by means of a plate-fin heat exchanger with liquefied nitrogen. The test results showed that, as the suction temperature decreased from 20°C to -150°C, the volumetric efficiency of the compressor dropped by 37.0%, and the power consumption decreased by 10.0%. The preheat of the gas by the pipe through the suction flange to suction valve was larger than 20°C as the suction temperature was -150°C, and this value increased with the decreased suction temperature. The pressure loss through the suction valve at lower suction temperature was larger than that at ambient temperature while the volume flow rate was kept the same.

  2. 40 CFR 264.1053 - Standards: Compressors.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... equipped with a sensor that will detect failure of the seal system, barrier fluid system, or both. (e)(1) Each sensor as required in paragraph (d) of this section shall be checked daily or shall be equipped... compressor is located within the boundary of an unmanned plant site, in which case the sensor must be...

  3. 40 CFR 265.1053 - Standards: Compressors.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... equipped with a sensor that will detect failure of the seal system, barrier fluid system, or both. (e)(1) Each sensor as required in paragraph (d) of this section shall be checked daily or shall be equipped... compressor is located within the boundary of an unmanned plant site, in which case the sensor must be...

  4. 30 CFR 75.344 - Compressors.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... air course or to the surface and equipped with sensors to monitor for heat and for carbon monoxide or smoke. The sensors shall deenergize power to the compressor, activate a visual and audible alarm located... every 31 days, sensors installed to monitor for carbon monoxide shall be calibrated with a...

  5. 30 CFR 75.344 - Compressors.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... air course or to the surface and equipped with sensors to monitor for heat and for carbon monoxide or smoke. The sensors shall deenergize power to the compressor, activate a visual and audible alarm located... every 31 days, sensors installed to monitor for carbon monoxide shall be calibrated with a...

  6. 30 CFR 75.344 - Compressors.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... air course or to the surface and equipped with sensors to monitor for heat and for carbon monoxide or smoke. The sensors shall deenergize power to the compressor, activate a visual and audible alarm located... every 31 days, sensors installed to monitor for carbon monoxide shall be calibrated with a...

  7. 30 CFR 75.344 - Compressors.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... air course or to the surface and equipped with sensors to monitor for heat and for carbon monoxide or smoke. The sensors shall deenergize power to the compressor, activate a visual and audible alarm located... every 31 days, sensors installed to monitor for carbon monoxide shall be calibrated with a...

  8. A 50 GHz GaAs FET MIC transmitter/receiver using hermetic miniature probe transitions

    NASA Astrophysics Data System (ADS)

    Ogawa, Koichi; Ishizaki, Toshio; Hashimoto, Koji; Sakakura, Makoto; Uwano, Tomoki

    1989-09-01

    A very compact 50-GHz-band transmitter/receiver for a video link is described. The RF assemblies used in the system consist of 25/50-GHz frequency doublers, a 25-GHz dielectric-resonator oscillator, and a 25-GHz FM modulator. The circuits make extensive use of microwave IC technology with all GaAs FETs as active elements. The frequency doublers exhibit a minimum conversion loss of 2.6 dB and a maximum output power of 11 dBm. The modulator is highly frequency stabilized by the dielectric resonator. Recently developed miniature probe microstrip-to-waveguide transitions permit the IC assemblies to be installed compactly in hermetically sealed packages. Design considerations and experimental data for the transition are presented. Using these technologies a transmitting power of 10 dBm and a receiver noise figure of 13 dB have been obtained.

  9. Hermetically sealable package for hybrid solid-state electronic devices and the like

    NASA Technical Reports Server (NTRS)

    Miller, Wilson N. (Inventor); Gray, Ormal E. (Inventor)

    1988-01-01

    A light-weight, inexpensively fabricated, hermetically sealable, repairable package for small electronic or electromechanical units, having multiple connections, is described. A molded ring frame of polyamide-imide plastic (Torlon) is attached along one edge to a base plate formed of a highly heat conducting material, such as aluminum or copper. Bores are placed through a base plate within the area of the edge surface of ring frame which result in an attachment of the ring frame to the base plate during molding. Electrical leads are molded into the ring frame. The leads are L-shaped gold-plated copper wires imbedded within widened portions of the side wall of the ring frame. Within the plastic ring frame wall the leads are bent (typically, though not necessarily at 90 deg) so that they project into the interior volume of the ring frame for connection to the solid state devices.

  10. The New York Schools Insurance Reciprocal.

    ERIC Educational Resources Information Center

    Lapetina, Alison J.

    1990-01-01

    Describes the New York Schools Insurance Reciprocal (NYSIR), which provides both property and liability coverage for school districts. A reciprocal is wholly owned by those insured. NYSIR insures 55 school district subscribers, providing a service that specifically accommodates school district needs and saves them money. (MLF)

  11. Reciprocal Tutoring: Design with Cognitive Load Sharing

    ERIC Educational Resources Information Center

    Chou, Chih-Yueh; Chan, Tak-Wai

    2016-01-01

    "Reciprocal tutoring," as reported in "Exploring the design of computer supports for reciprocal tutoring" (Chan and Chou 1997), has extended the meaning and scope of "intelligent tutoring" originally implemented in stand alone computers. This research is a follow-up to our studies on a "learning companion…

  12. The Effects of Reciprocal Teaching on Comprehension.

    ERIC Educational Resources Information Center

    Frances, Shannon M.; Eckart, Joyce A.

    An action research project investigated the effect of reciprocal teaching instruction and use on the comprehension of seventh-grade general English students. Reciprocal teaching is a form of dialogue structured around four skills--question generation, summarization, clarification, and prediction. These techniques are used in small group…

  13. Education, Gift and Reciprocity: A Preliminary Discussion

    ERIC Educational Resources Information Center

    Sabourin, Eric

    2013-01-01

    This paper analyzes the importance and role of the reciprocity relationship in education. It presents a review on the mobilization of the principle of reciprocity--in the anthropological but also sociological and economic senses--in educational processes, especially in adult education. The study is divided into three parts. The first part analyzes…

  14. An Introduction to the Onsager Reciprocal Relations

    ERIC Educational Resources Information Center

    Monroe, Charles W.; Newman, John

    2007-01-01

    The Onsager reciprocal relations are essential to multicomponent transport theory. A discussion of the principles that should be used to derive flux laws for coupled diffusion is presented here. Fluctuation theory is employed to determine the reciprocal relation for transport coefficients that characterize coupled mass and heat transfer in binary…

  15. Reflexive and Reciprocal Elements in Ixil.

    ERIC Educational Resources Information Center

    Ayres, Glenn

    1990-01-01

    Reflexives and reciprocals in Ixil, a Mayan language of Guatemala, appear to have features that distinguish them from reflexives surveyed in typological studies such as Faltz (1985) and Geniusiene (1987). Third person reflexives and reciprocals seem to have the form of a possessed noun optionally followed by a possessor NP. Moreover, reflexives…

  16. The mechanical design of a vapor compressor for a heat pump to be used in space

    NASA Technical Reports Server (NTRS)

    Berner, F.; Oesch, H.; Goetz, K.; Savage, C. J.

    1982-01-01

    A heat pump developed for use in Spacelab as a stand-alone refrigeration unit as well as within a fluid loop system is discussed. It will provide an active thermal control for payloads. Specifications for the heat pump were established: (1) heat removal rates at the source; (2) heat source temperatures from room temperature; (3) heat-sink fluid temperatures at condenser inlet; and (4) minimum power consumption. A reversed Carnot cycle heat pump using Freon 12 as working fluid incorporating a one-cylinder reciprocating compressor was selected. The maximum crankshaft speed was fixed relatively high at 100 rpm. The specified cooling rates then made it necessary to select a cylinder volume of 10 cu cm, which was obtained with a bore of 40 mm and a stroke of 8 mm.

  17. Multiplicative noise enhances spatial reciprocity

    NASA Astrophysics Data System (ADS)

    Yao, Yao; Chen, Shen-Shen

    2014-11-01

    Recent research has identified the heterogeneity as crucial for the evolution of cooperation in spatial population. However, the influence of heterogeneous noise is still lacking. Inspired by this interesting question, in this work, we try to incorporate heterogeneous noise into the evaluation of utility, where only a proportion of population possesses noise, whose range can also be tuned. We find that increasing heterogeneous noise monotonously promotes cooperation and even translates the full defection phase (of the homogeneous version) into the complete cooperation phase. Moreover, the promotion effect of this mechanism can be attributed to the leading role of cooperators who have the heterogeneous noise. These type of cooperators can attract more agents penetrating into the robust cooperator clusters, which is beyond the text of traditional spatial reciprocity. We hope that our work may shed light on the understanding of the cooperative behavior in the society.

  18. Methane emissions from natural gas compressor stations in the transmission and storage sector: measurements and comparisons with the EPA greenhouse gas reporting program protocol.

    PubMed

    Subramanian, R; Williams, Laurie L; Vaughn, Timothy L; Zimmerle, Daniel; Roscioli, Joseph R; Herndon, Scott C; Yacovitch, Tara I; Floerchinger, Cody; Tkacik, Daniel S; Mitchell, Austin L; Sullivan, Melissa R; Dallmann, Timothy R; Robinson, Allen L

    2015-03-01

    Equipment- and site-level methane emissions from 45 compressor stations in the transmission and storage (T&S) sector of the US natural gas system were measured, including 25 sites required to report under the EPA greenhouse gas reporting program (GHGRP). Direct measurements of fugitive and vented sources were combined with AP-42-based exhaust emission factors (for operating reciprocating engines and turbines) to produce a study onsite estimate. Site-level methane emissions were also concurrently measured with downwind-tracer-flux techniques. At most sites, these two independent estimates agreed within experimental uncertainty. Site-level methane emissions varied from 2-880 SCFM. Compressor vents, leaky isolation valves, reciprocating engine exhaust, and equipment leaks were major sources, and substantial emissions were observed at both operating and standby compressor stations. The site-level methane emission rates were highly skewed; the highest emitting 10% of sites (including two superemitters) contributed 50% of the aggregate methane emissions, while the lowest emitting 50% of sites contributed less than 10% of the aggregate emissions. Excluding the two superemitters, study-average methane emissions from compressor housings and noncompressor sources are comparable to or lower than the corresponding effective emission factors used in the EPA greenhouse gas inventory. If the two superemitters are included in the analysis, then the average emission factors based on this study could exceed the EPA greenhouse gas inventory emission factors, which highlights the potentially important contribution of superemitters to national emissions. However, quantification of their influence requires knowledge of the magnitude and frequency of superemitters across the entire T&S sector. Only 38% of the methane emissions measured by the comprehensive onsite measurements were reportable under the new EPA GHGRP because of a combination of inaccurate emission factors for leakers and

  19. Methane emissions from natural gas compressor stations in the transmission and storage sector: measurements and comparisons with the EPA greenhouse gas reporting program protocol.

    PubMed

    Subramanian, R; Williams, Laurie L; Vaughn, Timothy L; Zimmerle, Daniel; Roscioli, Joseph R; Herndon, Scott C; Yacovitch, Tara I; Floerchinger, Cody; Tkacik, Daniel S; Mitchell, Austin L; Sullivan, Melissa R; Dallmann, Timothy R; Robinson, Allen L

    2015-03-01

    Equipment- and site-level methane emissions from 45 compressor stations in the transmission and storage (T&S) sector of the US natural gas system were measured, including 25 sites required to report under the EPA greenhouse gas reporting program (GHGRP). Direct measurements of fugitive and vented sources were combined with AP-42-based exhaust emission factors (for operating reciprocating engines and turbines) to produce a study onsite estimate. Site-level methane emissions were also concurrently measured with downwind-tracer-flux techniques. At most sites, these two independent estimates agreed within experimental uncertainty. Site-level methane emissions varied from 2-880 SCFM. Compressor vents, leaky isolation valves, reciprocating engine exhaust, and equipment leaks were major sources, and substantial emissions were observed at both operating and standby compressor stations. The site-level methane emission rates were highly skewed; the highest emitting 10% of sites (including two superemitters) contributed 50% of the aggregate methane emissions, while the lowest emitting 50% of sites contributed less than 10% of the aggregate emissions. Excluding the two superemitters, study-average methane emissions from compressor housings and noncompressor sources are comparable to or lower than the corresponding effective emission factors used in the EPA greenhouse gas inventory. If the two superemitters are included in the analysis, then the average emission factors based on this study could exceed the EPA greenhouse gas inventory emission factors, which highlights the potentially important contribution of superemitters to national emissions. However, quantification of their influence requires knowledge of the magnitude and frequency of superemitters across the entire T&S sector. Only 38% of the methane emissions measured by the comprehensive onsite measurements were reportable under the new EPA GHGRP because of a combination of inaccurate emission factors for leakers and

  20. A theoretical and experimental study of a novel refrigerant compressor

    NASA Astrophysics Data System (ADS)

    Eames, I. W.

    A refrigerant compressor concept was envisaged consisting of a small scale centrifugal compressor driven by a high frequency induction motor on a common shaft with an impeller supported in aerodynamic bearings. The combination of state-of-the-art compressor, bearing and motor technologies potentially provides refrigerator designers with improved system performance and better compressor reliability with significant reductions in weight and physical size at reduced capital and running costs. A detailed description of the prototype compressor unit is included. The concept is compared with conventional compressor systems, and key areas of research requiring detailed investigation are identified. The following are described and/or evaluated: (1) the results of a literature survey into performance of centrifugal compressors; (2) the electric motor; (3) an investigation into the design of the drive shaft and bearing assemblies; (4) external and internal sources of machine vibration; (5) the manufacture of the prototype compressor unit; (6) testing of the compressor unit; (7) development problems encountered during testing; and (8) a computer simulation study of the behavior of a refrigeration system incorporating the prototype compressor. Aspects of the manufacture considered include surface finishes, tolerancing, heat treatments, and balancing processes.

  1. Reciprocity and Ethical Tuberculosis Treatment and Control.

    PubMed

    Silva, Diego S; Dawson, Angus; Upshur, Ross E G

    2016-03-01

    This paper explores the notion of reciprocity in the context of active pulmonary and laryngeal tuberculosis (TB) treatment and related control policies and practices. We seek to do three things: First, we sketch the background to contemporary global TB care and suggest that poverty is a key feature when considering the treatment of TB patients. We use two examples from TB care to explore the role of reciprocity: isolation and the use of novel TB drugs. Second, we explore alternative means of justifying the use of reciprocity through appeal to different moral and political theoretical traditions (i.e., virtue ethics, deontology, and consequentialism). We suggest that each theory can be used to provide reasons to take reciprocity seriously as an independent moral concept, despite any other differences. Third, we explore general meanings and uses of the concept of reciprocity, with the primary intention of demonstrating that it cannot be simply reduced to other more frequently invoked moral concepts such as beneficence or justice. We argue that reciprocity can function as a mid-level principle in public health, and generally, captures a core social obligation arising once an individual or group is burdened as a result of acting for the benefit of others (even if they derive a benefit themselves). We conclude that while more needs to be explored in relation to the theoretical justification and application of reciprocity, sufficient arguments can be made for it to be taken more seriously as a key principle within public health ethics and bioethics more generally. PMID:26797512

  2. Reciprocity and Ethical Tuberculosis Treatment and Control.

    PubMed

    Silva, Diego S; Dawson, Angus; Upshur, Ross E G

    2016-03-01

    This paper explores the notion of reciprocity in the context of active pulmonary and laryngeal tuberculosis (TB) treatment and related control policies and practices. We seek to do three things: First, we sketch the background to contemporary global TB care and suggest that poverty is a key feature when considering the treatment of TB patients. We use two examples from TB care to explore the role of reciprocity: isolation and the use of novel TB drugs. Second, we explore alternative means of justifying the use of reciprocity through appeal to different moral and political theoretical traditions (i.e., virtue ethics, deontology, and consequentialism). We suggest that each theory can be used to provide reasons to take reciprocity seriously as an independent moral concept, despite any other differences. Third, we explore general meanings and uses of the concept of reciprocity, with the primary intention of demonstrating that it cannot be simply reduced to other more frequently invoked moral concepts such as beneficence or justice. We argue that reciprocity can function as a mid-level principle in public health, and generally, captures a core social obligation arising once an individual or group is burdened as a result of acting for the benefit of others (even if they derive a benefit themselves). We conclude that while more needs to be explored in relation to the theoretical justification and application of reciprocity, sufficient arguments can be made for it to be taken more seriously as a key principle within public health ethics and bioethics more generally.

  3. Two distinct neural mechanisms underlying indirect reciprocity.

    PubMed

    Watanabe, Takamitsu; Takezawa, Masanori; Nakawake, Yo; Kunimatsu, Akira; Yamasue, Hidenori; Nakamura, Mitsuhiro; Miyashita, Yasushi; Masuda, Naoki

    2014-03-18

    Cooperation is a hallmark of human society. Humans often cooperate with strangers even if they will not meet each other again. This so-called indirect reciprocity enables large-scale cooperation among nonkin and can occur based on a reputation mechanism or as a succession of pay-it-forward behavior. Here, we provide the functional and anatomical neural evidence for two distinct mechanisms governing the two types of indirect reciprocity. Cooperation occurring as reputation-based reciprocity specifically recruited the precuneus, a region associated with self-centered cognition. During such cooperative behavior, the precuneus was functionally connected with the caudate, a region linking rewards to behavior. Furthermore, the precuneus of a cooperative subject had a strong resting-state functional connectivity (rsFC) with the caudate and a large gray matter volume. In contrast, pay-it-forward reciprocity recruited the anterior insula (AI), a brain region associated with affective empathy. The AI was functionally connected with the caudate during cooperation occurring as pay-it-forward reciprocity, and its gray matter volume and rsFC with the caudate predicted the tendency of such cooperation. The revealed difference is consistent with the existing results of evolutionary game theory: although reputation-based indirect reciprocity robustly evolves as a self-interested behavior in theory, pay-it-forward indirect reciprocity does not on its own. The present study provides neural mechanisms underlying indirect reciprocity and suggests that pay-it-forward reciprocity may not occur as myopic profit maximization but elicit emotional rewards.

  4. Two distinct neural mechanisms underlying indirect reciprocity

    PubMed Central

    Watanabe, Takamitsu; Takezawa, Masanori; Nakawake, Yo; Kunimatsu, Akira; Yamasue, Hidenori; Nakamura, Mitsuhiro; Miyashita, Yasushi; Masuda, Naoki

    2014-01-01

    Cooperation is a hallmark of human society. Humans often cooperate with strangers even if they will not meet each other again. This so-called indirect reciprocity enables large-scale cooperation among nonkin and can occur based on a reputation mechanism or as a succession of pay-it-forward behavior. Here, we provide the functional and anatomical neural evidence for two distinct mechanisms governing the two types of indirect reciprocity. Cooperation occurring as reputation-based reciprocity specifically recruited the precuneus, a region associated with self-centered cognition. During such cooperative behavior, the precuneus was functionally connected with the caudate, a region linking rewards to behavior. Furthermore, the precuneus of a cooperative subject had a strong resting-state functional connectivity (rsFC) with the caudate and a large gray matter volume. In contrast, pay-it-forward reciprocity recruited the anterior insula (AI), a brain region associated with affective empathy. The AI was functionally connected with the caudate during cooperation occurring as pay-it-forward reciprocity, and its gray matter volume and rsFC with the caudate predicted the tendency of such cooperation. The revealed difference is consistent with the existing results of evolutionary game theory: although reputation-based indirect reciprocity robustly evolves as a self-interested behavior in theory, pay-it-forward indirect reciprocity does not on its own. The present study provides neural mechanisms underlying indirect reciprocity and suggests that pay-it-forward reciprocity may not occur as myopic profit maximization but elicit emotional rewards. PMID:24591599

  5. ADVANCED RECIPROCATING COMPRESSION TECHNOLOGY (ARCT)

    SciTech Connect

    Danny M. Deffenbaugh; Klaus Brun; Ralph E. Harris; J. Pete Harrell; Robert J. Mckee; J. Jeffrey Moore; Steven J. Svedeman; Anthony J. Smalley; Eugene L. Broerman; Robert A Hart; Marybeth G. Nored; Ryan S. Gernentz; Shane P. Siebenaler

    2005-12-01

    The U.S. natural gas pipeline industry is facing the twin challenges of increased flexibility and capacity expansion. To meet these challenges, the industry requires improved choices in gas compression to address new construction and enhancement of the currently installed infrastructure. The current fleet of installed reciprocating compression is primarily slow-speed integral machines. Most new reciprocating compression is and will be large, high-speed separable units. The major challenges with the fleet of slow-speed integral machines are: limited flexibility and a large range in performance. In an attempt to increase flexibility, many operators are choosing to single-act cylinders, which are causing reduced reliability and integrity. While the best performing units in the fleet exhibit thermal efficiencies between 90% and 92%, the low performers are running down to 50% with the mean at about 80%. The major cause for this large disparity is due to installation losses in the pulsation control system. In the better performers, the losses are about evenly split between installation losses and valve losses. The major challenges for high-speed machines are: cylinder nozzle pulsations, mechanical vibrations due to cylinder stretch, short valve life, and low thermal performance. To shift nozzle pulsation to higher orders, nozzles are shortened, and to dampen the amplitudes, orifices are added. The shortened nozzles result in mechanical coupling with the cylinder, thereby, causing increased vibration due to the cylinder stretch mode. Valve life is even shorter than for slow speeds and can be on the order of a few months. The thermal efficiency is 10% to 15% lower than slow-speed equipment with the best performance in the 75% to 80% range. The goal of this advanced reciprocating compression program is to develop the technology for both high speed and low speed compression that will expand unit flexibility, increase thermal efficiency, and increase reliability and integrity

  6. High stability design for new centrifugal compressor

    NASA Technical Reports Server (NTRS)

    Kanki, H.; Katayama, K.; Morii, S.; Mouri, Y.; Umemura, S.; Ozawa, U.; Oda, T.

    1989-01-01

    It is essential that high-performance centrifugal compressors be free of subsynchronous vibrations. A new high-performance centrifugal compressor has been developed by applying the latest rotordynamics knowledge and design techniques: (1) To improve the system damping, a specially designed oil film seal was developed. This seal attained a damping ratio three times that of the conventional design. The oil film seal contains a special damper ring in the seal cartridge. (2) To reduce the destabilizing effect of the labyrinth seal, a special swirl canceler (anti-swirl nozzle) was applied to the balance piston seal. (3) To confirm the system damping margin, the dynamic simulation rotor model test and the full load test applied the vibration exciting test in actual load conditions.

  7. Instability of multistage compressor K1501

    NASA Technical Reports Server (NTRS)

    Zhou, Ren-Mu

    1987-01-01

    The K1501 compressor, driven by a steam turbine, is used to transport synthetic gas in fertilizer plants of 1000 tons daily production. The turbo-compressor set, which had been in operation since 1982, vibrated rather intensely, and its maximum load was only about 95 percent of the normal value. Damaging vibration to pads and gas-sealing labyrinths occurred three times from 1982 to 1983 and resulted in considerable economic loss. From the characteristics of the vibration, we suspected its cause to be rotor instability due to labyrinth-seal excitation. But, for lack of experience, the problem was not addressed for two years. Finally, we determined that the instability was indeed produced by labyrinth-seal excitation and corrected this problem by injecting gas into the middle-diaphragm labyrinths. This paper primarily discusses the failure and the remedy described above.

  8. Self-reciprocating radioisotope-powered cantilever

    NASA Astrophysics Data System (ADS)

    Li, Hui; Lal, Amit; Blanchard, James; Henderson, Douglass

    2002-07-01

    A reciprocating cantilever utilizing emitted charges from a millicurie radioisotope thin film is presented. The actuator realizes a direct collected-charge-to-motion conversion. The reciprocation is obtained by self-timed contact between the cantilever and the radioisotope source. A static model balancing the electrostatic and mechanical forces from an equivalent circuit leads to an analytical solution useful for device characterization. Measured reciprocating periods agree with predicted values from the analytical model. A scaling analysis shows that microscale arrays of such cantilevers provide an integrated sensor and actuator platform.

  9. Combined cold compressor/ejector helium refrigerator

    DOEpatents

    Brown, Donald P.

    1985-01-01

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

  10. Combined cold compressor/ejector helium refrigerator

    DOEpatents

    Brown, D.P.

    1984-06-05

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

  11. Amplifier/compressor fiber Raman lasers.

    PubMed

    Islam, M N; Mollenauer, L F; Stolen, R H; Simpson, J R; Shang, H T

    1987-10-01

    We show that the chirp from cross-phase modulation (XPM) dominates the operation of fiber Raman lasers (FRL's). Thus a FRL in the anomalous group-velocity regime is best described as a XPM-chirped Raman amplifier followed by a linear fiber compressor. While the output of such a laser is generally a narrow pulse with a broad pedestal, we show both experimentally and by computer simulation that negligible background is achievable.

  12. Efficiency study of oil cooling of a screw compressor

    SciTech Connect

    Tree, D.R.; McKellar, M.G. . Ray W. Herrick Labs.); Fresco, A. )

    1990-01-01

    One of the major goals of all compressor manufacturers is to design and build as efficient a compressor as possible. In a screw compressor it appears that the way the compressor is cooled can have an effect on the compressor's efficiency. This paper presents experimental data on three different screw compressor cooling methods: Liquid Refrigerant Injection Cooling System; Thermosyphon Cooling System; and Oil Injection System. All tests were conducted on a hot gas bypass system using refrigerant R-22. The data taken shows that the Oil Injection System is slightly better than the other two. These tests should be repeated with a higher oil flow rate and ammonia as the working fluid. 10 figs.

  13. Preliminary design study of advanced multistage axial flow core compressors

    NASA Technical Reports Server (NTRS)

    Wisler, D. C.; Koch, C. C.; Smith, L. H., Jr.

    1977-01-01

    A preliminary design study was conducted to identify an advanced core compressor for use in new high-bypass-ratio turbofan engines to be introduced into commercial service in the 1980's. An evaluation of anticipated compressor and related component 1985 state-of-the-art technology was conducted. A parametric screening study covering a large number of compressor designs was conducted to determine the influence of the major compressor design features on efficiency, weight, cost, blade life, aircraft direct operating cost, and fuel usage. The trends observed in the parametric screening study were used to develop three high-efficiency, high-economic-payoff compressor designs. These three compressors were studied in greater detail to better evaluate their aerodynamic and mechanical feasibility.

  14. IEMDC - In-Line Electric Motor Driven Compressor

    SciTech Connect

    Michael J. Crowley

    2004-03-31

    This report covers the fifth quarter (01/01/04 to 03/31/04) of the In-Line Electric Motor Driven Compressor (IEMDC) project. Design efforts on the IEMDC continued with compressor efforts focused on performing aerodynamic analyses. These analyses were conducted using computational fluid dynamics. Compressor efforts also entailed developing mechanical designs of components through the use of solid models and working on project deliverables. Electric motor efforts focused on the design of the magnetic bearing system, motor pressure housing, and the motor-compressor interface. The mechanical evaluation of the main interface from both the perspective of the compressor manufacturer and electric motor manufacturer indicates that an acceptable design has been achieved. All mechanical and aerodynamic design efforts have resulted in considerable progress being made towards the completion of the compressor and electric motor design and towards the successful completion of the IEMDC unit.

  15. Aerodynamic Design of Axial-flow Compressors. Volume III

    NASA Technical Reports Server (NTRS)

    Johnson, Irving A; Bullock, Robert O; Graham, Robert W; Costilow, Eleanor L; Huppert, Merle C; Benser, William A; Herzig, Howard Z; Hansen, Arthur G; Jackson, Robert J; Yohner, Peggy L; Dugan, Ames F , Jr

    1956-01-01

    Chapters XI to XIII concern the unsteady compressor operation arising when compressor blade elements stall. The fields of compressor stall and surge are reviewed in Chapters XI and XII, respectively. The part-speed operating problem in high-pressure-ratio multistage axial-flow compressors is analyzed in Chapter XIII. Chapter XIV summarizes design methods and theories that extend beyond the simplified two-dimensional approach used previously in the report. Chapter XV extends this three-dimensional treatment by summarizing the literature on secondary flows and boundary layer effects. Charts for determining the effects of errors in design parameters and experimental measurements on compressor performance are given in Chapters XVI. Chapter XVII reviews existing literature on compressor and turbine matching techniques.

  16. Object-oriented Technology for Compressor Simulation

    NASA Technical Reports Server (NTRS)

    Drummond, C. K.; Follen, G. J.; Cannon, M. R.

    1994-01-01

    An object-oriented basis for interdisciplinary compressor simulation can, in principle, overcome several barriers associated with the traditional structured (procedural) development approach. This paper presents the results of a research effort with the objective to explore the repercussions on design, analysis, and implementation of a compressor model in an object oriented (OO) language, and to examine the ability of the OO system design to accommodate computational fluid dynamics (CFD) code for compressor performance prediction. Three fundamental results are that: (1) the selection of the object oriented language is not the central issue; enhanced (interdisciplinary) analysis capability derives from a broader focus on object-oriented technology; (2) object-oriented designs will produce more effective and reusable computer programs when the technology is applied to issues involving complex system inter-relationships (more so than when addressing the complex physics of an isolated discipline); and (3) the concept of disposable prototypes is effective for exploratory research programs, but this requires organizations to have a commensurate long-term perspective. This work also suggests that interdisciplinary simulation can be effectively accomplished (over several levels of fidelity) with a mixed language treatment (i.e., FORTRAN-C++), reinforcing the notion the OO technology implementation into simulations is a 'journey' in which the syntax can, by design, continuously evolve.

  17. METAL HYDRIDE HYDROGEN COMPRESSORS: A REVIEW

    SciTech Connect

    Bowman Jr, Robert C; Yartys, Dr. Volodymyr A.; Lototskyy, Dr. Michael V; Pollet, Dr. B.G.

    2014-01-01

    Metal hydride (MH) thermal sorption compression is an efficient and reliable method allowing a conversion of energy from heat into a compressed hydrogen gas. The most important component of such a thermal engine the metal hydride material itself should possess several material features in order to achieve an efficient performance in the hydrogen compression. Apart from the hydrogen storage characteristics important for every solid H storage material (e.g. gravimetric and volumetric efficiency of H storage, hydrogen sorption kinetics and effective thermal conductivity), the thermodynamics of the metal-hydrogen systems is of primary importance resulting in a temperature dependence of the absorption/desorption pressures). Several specific features should be optimized to govern the performance of the MH-compressors including synchronisation of the pressure plateaus for multi-stage compressors, reduction of slope of the isotherms and hysteresis, increase of cycling stability and life time, together with challenges in system design associated with volume expansion of the metal matrix during the hydrogenation. The present review summarises numerous papers and patent literature dealing with MH hydrogen compression technology. The review considers (a) fundamental aspects of materials development with a focus on structure and phase equilibria in the metal-hydrogen systems suitable for the hydrogen compression; and (b) applied aspects, including their consideration from the applied thermodynamic viewpoint, system design features and performances of the metal hydride compressors and major applications.

  18. Application of I-structure though-glass interconnect filled with submicron gold particles to a hermetic sealing device

    NASA Astrophysics Data System (ADS)

    Nomura, Kazuya; Okada, Akiko; Shoji, Shuichi; Ogashiwa, Toshinori; Mizuno, Jun

    2016-10-01

    We propose hermetic sealing of a glass-to-glass structure with an I-structure through-glass interconnect via (TGV) filled with submicron Au particles. The top and bottom bumps and the TGV were formed by a simple filling process with a bump-patterned dry film resist. The sealing devices consisting of two glass substrates were bonded via Au interlayers. Vacuum ultraviolet irradiation in the presence of oxygen gas (VUV/O3) pretreatment was used for low-temperature Au-Au bonding at 200 °C. The bonded samples showed He leakage rates of less than 1.3  ×  10-9 Pa m3 s-1. The cross-sectional scanning electron microscope images of the fabricated I-structure TGV showed perfect adhesion between the I-structure TGV and glass substrate. These results indicate that the proposed I-structure TGV is suitable for hermetic sealing devices.

  19. Reciprocating piston internal combustion engine

    SciTech Connect

    Hayashi, Y.

    1986-04-15

    A reciprocating piston internal combustion engine is described which consists of: a piston movably disposed within an engine cylinder, the piston having a top surface and a piston ring, the engine cylinder and the top surface of the piston defining a combustion chamber, the piston having first and second sections which are divided by a vertical plane containing an axis of a piston pin, the first section being formed with a major thrust surface and the second section being formed with a minor thrust surface; and means for thrusting the piston against a major thrust side wall of the cylinder before the piston reaches top dead center in the cylinder, the thrusting means comprising: means defining a space in the piston, the space communicating with the combustion chamber and being located in the piston second section; a movable member disposed within the space, the movable member being capable of being thrust in the direction of a minor thrust side wall of the cylinder by gas pressure within the combustion chamber and being arranged to thrust the piston ring against the minor thrust side wall when thrust by the gas pressure; and means for producing gas pressure within the combustion chamber such that the gas pressure enters the space at the compression stroke of the engine so that the movable member receives the gas pressure and is thrust toward the minor thrust side wall of the cylinder such that the piston is thrust against a major thrust side wall of the cylinder.

  20. Reciprocal engine with floating liner

    SciTech Connect

    Paul, M.A.; Paul, A.

    1989-06-27

    An internal combustion engine with a heat recovery system is described comprising: a cylinder with a cylinder wall; a piston with a piston head, the piston being reciprocally displaceable in the cylinder; a fuel injection means with fuel connected to the cylinder; and, an air intake passage and an exhaust passage connected to the cylinder, such that air is delivered to the cylinder, compressed by the piston, and fuel from the fuel injection means is delivered to the cylinder and combusted in a working chamber; wherein the heat recovery system includes an air-porous, heat-resistant tubular liner suspended in the cylinder and displaced from the wall of the cylinder, the piston having a deep groove with inner and outer walls in the head of the piston into which the liner is received when the piston is displaced compressing the air, the liner being spaced from the inner and outer walls of the groove such that three insulating zones are provided between combustion gases in the cylinder and the cylinder wall during displacement of the piston.

  1. Critical speed measurements in the Tevatron cold compressors

    SciTech Connect

    DeGraff, B.; Bossert, R.; Martinez, A.; Soyars, W.M.; /Fermilab

    2006-01-01

    The Fermilab Tevatron cryogenic system utilizes high-speed centrifugal cold compressors, manufactured by Ishikawajima-Harima Heavy Industries Co. Ltd. (IHI), for high energy operations. Nominal operating range for these compressors is 43,000 to 85,000 rpm. Past foil bearing failures prompted investigation to determine if critical speeds for operating compressors fall within operating range. Data acquisition hardware and software settings will be discussed for measuring liftoff, first critical and second critical speeds. Several tests provided comparisons between an optical displacement probe and accelerometer measurements. Vibration data and analysis of the 20 Tevatron ring cold compressors will be presented.

  2. Development of an adsorption compressor for use in cryogenic refrigeration

    NASA Technical Reports Server (NTRS)

    Schember, Helen R.

    1989-01-01

    A new compressor with no moving parts has been developed which is able to supply a source of high-pressure gas to a Joule-Thompson based cryogenic refrigerator. The compressor relies on a newly implemented combination of high-surface-area Saran carbon (sorbent) and krypton gas (working fluid). In addition, an integral gas-gap heat switch is used to provide improved overall efficiency. A prototype compressor has been designed, built, and tested as a part of the Jet Propulsion Laboratory effort in sorption refrigeration. Performance data from the prototype unit described here demonstrate successful compressor performance and good agreement with theoretical predictions.

  3. An inquiry into relationship suicides and reciprocity.

    PubMed

    Davis, Mark S; Callanan, Valerie J; Lester, David; Haines, Janet

    2009-10-01

    Few theories on suicide have been grounded in the norm of reciprocity. There is literature on suicide, however, describing motivations such as retaliation and retreat which can be interpreted as modes of adaptation to the norm of reciprocity. We propose a reciprocity-based theory to explain suicides associated with relationship problems. Employing a content analysis of suicide notes, we tested the theory, finding evidence of exploitation, exploiter guilt, retaliation, and retreat as motives for committing relationship-based suicide. Reciprocity-based note writers were more likely to have used alcohol or drugs in the hours prior to committing suicide, and they were also more likely to have made their intentions known beforehand. Implications for future research as well as for suicide prevention are discussed.

  4. 78 FR 53792 - Draft Guidance for Reciprocity

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-08-30

    ... (Reciprocity).'' The document has been updated from the previous revision to include safety culture, security.... Brian J. McDermott, Director, Division of Materials Safety and State Agreements, Office of Federal...

  5. Helium compressors for closed-cycle, 4.5-Kelvin refrigerators

    NASA Technical Reports Server (NTRS)

    Hanson, T. R.

    1992-01-01

    An improved helium compressor for traveling-wave maser and closed-cycle refrigerator systems was developed and is currently being supplied to the DSN. This new 5-hp compressor package is designed to replace the current 3-hp DSN compressors. The new compressor package was designed to retrofit into the existing 3-hp compressor frame and reuse many of the same components, therefore saving the cost of documenting and fabricating these components when implementing a new 5-hp compressor.

  6. Study of the potential for improving the economics of hydrogen liquefaction through the use of centrifugal compressors and the addition of a heavy water plant

    NASA Technical Reports Server (NTRS)

    Baker, C. R.

    1977-01-01

    An approach to the liquefaction of hydrogen was developed which permits the application of standard centrifugal compressors in place of reciprocating machines. A second fluid, such as propane, is added to the hydrogen prior to compression to form a mixture having a molecular weight much greater than that of hydrogen alone, so that a standard centrifugal compressor can be used. After compression, the mixture is cooled to cryogenic temperature levels where the propane condenses out of the mixture and is separated as a liquid. Since a small amount of deuterium is produced during hydrogen liquefaction, the potential of recovering deuterium and selling it as a co-product was investigated. Deuterium, in the form of heavy water, can be used in certain nuclear reactors as a neutron moderator to reduce the neutron velocity and enhance the probability of neutron collision with uranium nucleii.

  7. On-Farm Evaluation of Hermetic Technology Against Maize Storage Pests in Kenya.

    PubMed

    Likhayo, Paddy; Bruce, Anani Y; Mutambuki, Kimondo; Tefera, Tadele; Mueke, Jones

    2016-08-01

    On-farm trial with a total of 32 farmers in eight villages of Naivasha and Nakuru areas of Kenya was conducted between December 2013 and September 2014 to evaluate hermetic grain storage technologies under farmers' management conditions. The storage technologies evaluated were metal silo and SuperGrain IV-R bag alongside the standard woven polypropylene bag with or without Actellic super dust. Moisture content, insect population, grain discoloration, and weight loss were analyzed 90, 180, and 270 d after storage. Grain moisture content remained stable over the storage period. Both metal silo and SuperGrain IV-R bag suppressed insect population, prevented grain loss and cross-infestation of insects from the surrounding environment. On the contrary, polypropylene bags allowed rapid build up of insect population and re-infestation from the surrounding environment. Grain weight losses were 1.5% in the metal silo and 1.8% in the SuperGrain IV-R bags compared to 32% in the polypropylene bags without Actellic Super dust, 270 d after storage. The present study, therefore, demonstrates that storing grains either in metal silo or SuperGrain IV-R bags would benefit farmers in reducing grain losses and improving quality. The study was of great interest to the farmers, grain storage scientists, and food security experts.

  8. Electrodeposition of platinum-iridium alloy nanowires for hermetic packaging of microelectronics.

    PubMed

    Petrossians, Artin; Whalen, John J; Weiland, James D; Mansfeld, Florian

    2012-01-01

    An electrodeposition technique was applied for fabrication of dense platinum-iridium alloy nanowires as interconnect structures in hermetic microelectronic packaging to be used in implantable devices. Vertically aligned arrays of platinum-iridium alloy nanowires with controllable length and a diameter of about 200 nm were fabricated using a cyclic potential technique from a novel electrodeposition bath in nanoporous aluminum oxide templates. Ti/Au thin films were sputter deposited on one side of the alumina membranes to form a base material for electrodeposition. Scanning Electron Microscopy (SEM) and Energy Dispersive Spectroscopy (EDS) were used to characterize the morphology and the chemical composition of the nanowires, respectively. SEM micrographs revealed that the electrodeposited nanowires have dense and compact structures. EDS analysis showed a 60:40% platinum-iridium nanowire composition. Deposition rates were estimated by determining nanowire length as a function of deposition time. High Resolution Transmission Electron Microscopy (HRTEM) images revealed that the nanowires have a nanocrystalline structure with grain sizes ranging from 3 nm to 5 nm. Helium leak tests performed using a helium leak detector showed leak rates as low as 1 × 10(-11) mbar L s(-1) indicating that dense nanowires were electrodeposited inside the nanoporous membranes. Comparison of electrical measurements on platinum and platinum-iridium nanowires revealed that platinum-iridium nanowires have improved electrical conductivity.

  9. Measuring mass flows in hermetically sealed MEMS and MOEMS to ensure device reliability

    NASA Astrophysics Data System (ADS)

    Kullberg, R. C.; Rossiter, D. J.

    2008-02-01

    Many MEMs and MOEMs devices require controlled ambient environments for successful operation. Controlled ambients are usually obtained via hermetic packaging. These controlled environments must first be obtained and then maintained to prevent their degradation over the device lifetime. Controlled ambients decay in quality over time due to various mechanisms including leaks, permeation, poor processing and outgassing of species like hydrogen, water and organics external and internal to the package. The key to controlling the process of degradation is to understand in a quantitative manner which species are present and their mass flow rates into the controlled ambient. The current work describes a new technique for determining these species and mass flow rates. This new technology provides tremendous sensitivity to package volumes < 0.01cc compared to standard quadrupole techniques, which are applicable to samples larger than 0.01 cc. The technology is based on a high speed, high mass resolution, and highly sensitive Time-Of-Flight (TOF) spectrometer to test the tiniest of devices with significant advancement in signal-to-noise ratios. Key operational parameters demonstrated include: - Spectra Acquisition speed: 1 full spectra every 20 μs. - Mass Range: mass 2 to 150 standard (2-500 capable) - Mass resolution: 0.1 AMU - Calibration Fixtures: 0.0001, 0.0005, 0.001, 0.005 and 0.01 cc - Sample temperature: 100°C standard (room temperature to 150°C capable).

  10. Advanced materials for aerospace and biomedical applications: New glasses for hermetic titanium seals

    SciTech Connect

    Brow, R.K.; Tallant, D.R.; Crowder, S.V.

    1996-11-01

    Titanium and titanium alloys have an outstanding strength-to-weight ratio and corrosion resistance and so are materials of choice for a variety of aerospace and biomedical applications. Such applications are limited by the lack of a viable hermetic glass sealing technology. Conventional silicate sealing glasses are readily reduced by titanium to form interfacial silicides that are incompatible with a robust glass/metal seal. Borate-based glasses undergo a similar thermochemistry and are reduced to a titanium boride. The kinetics of this reactions, however, are apparently slower and so a deleterious interface does not form. Chemically durable lanthanoborate glasses were examined as candidate sealing compositions. The compositions, properties, and structures of several alkaline earth, alumina, and titania lanthanoborate glass forming systems were evaluated and this information was used as the basis for a designed experiment to optimize compositions for Ti-sealing. A number of viable compositions were identified and sealing procedures established. Finally, glass formation, properties, and structure of biocompatible Fe{sub 2}O{sub 3}- and TiO{sub 2}-doped calcium phosphate systems were also evaluated.

  11. A polymer-metal two step sealing concept for hermetic neural implant packages.

    PubMed

    Kohler, Fabian; Kiele, Patrick; Ordonez, Juan S; Stieglitz, Thomas; Schuettler, Martin

    2014-01-01

    In this paper, we introduce a technique for double-sealed ceramic packages for the long-term protection of implanted electronics against body fluids. A sequential sealing procedure consisting of a first step, during which the package is sealed with epoxy, protecting the implant electronics from aggressive flux fumes. These result from the application of the actual moisture barrier which is a metal seal applied in a second step by soft soldering. Epoxy sealing is carried out in helium atmosphere for later fine leak testing. The solder seal is applied on the laboratory bench. After the first sealing step, a satisfactory barrier for moisture is already achieved with values for helium leakage of usually LHe = 6·10(-8) mbar 1 s(-1). After solder sealing, a very low leakage rate of LHe ≤ 1·10(-12) mbar 1 s(-1) was found, which was the lower detection limit of the measurement setup, suggesting excellent hermeticity and hence moisture barrier. Presuming an implant package volume of V ≥ 0.5 cm(3), the time to reach a critical humidity of p = 5000 ppm H2O inside the package will be longer than any anticipated average life of human patients. PMID:25570864

  12. Low temperature wafer-level bonding for hermetic packaging of 3D microsystems

    NASA Astrophysics Data System (ADS)

    Tan, C. S.; Fan, J.; Lim, D. F.; Chong, G. Y.; Li, K. H.

    2011-07-01

    Metallic copper-copper (Cu-Cu) thermo-compression bonding, oxide-oxide (SiO2-SiO2) fusion bonding and silicon-silicon (Si-Si) direct bonding are investigated for potential application as hermetic seal in 3D microsystem packaging. Cavities are etched to a volume of 1.4 × 10-3 cm3 in accordance with the MIL-STD-883E standard prescribed for microelectronics packaging. In the case of metal bonding, a clean Cu layer with a thickness of 300 nm and a Ti barrier layer with an underlying thickness of 50 nm are used. The wafer pair is bonded at 300 °C under the application of a bonding force of 5500 N for 1 h. On the other hand, Si-Si bonding and SiO2-SiO2 bonding are initiated at room ambient after surface activation, followed by annealing in inert ambient at 300 °C for 1 h. The bonded cavities are stored in a helium bomb chamber and the leak rate is measured with a mass spectrometer. An excellent helium leak rate below 5 × 10-9 atm cm3 s-1 is detected for all cases and this is at least ten times better than the reject limit.

  13. A test microchip for evaluation of hermetic packaging technology for biomedical prosthetic implants.

    PubMed

    Kazemi, Mohammad; Basham, Eric; Sivaprakasam, Mohanasankar; Wang, Guoxing; Rodger, Damien; Weiland, James; Tai, Y C; Liu, Wentai; Humayun, Mark

    2004-01-01

    The development of a test chip that will be used to evaluate a hermetic and biocompatible package for the driving CMOS circuitry of a retinal prosthesis is described. The package design is estimated to be about 2 x 2 x 0.3 mm(3) and will be formed by conformal layers of parylene and a metal (e.g. titanium) as inner and outer protections, respectively. The test chip has been specifically designed for evaluation of the packaging technology. It consists of many blocks of analog and digital components as well as relative humidity and temperature sensors. The test chip has more probe points than a typical chip, allowing a more thorough evaluation of circuit behavior during the testing. This chip will first be coated in a layer of parylene C and soaked in heated isotonic saline for an extended period of time. Every block in the chip will then be tested for functionality using the surface probe points. The next step is to coat the surface of another test chip with parylene and a metal and repeat these soak tests. The results will then be analyzed and mean time-to-failure for the different samples will then be computed. Using the accelerated testing paradigm, these results will then be extrapolated to mean time-to-failure in the operating intraocular environment. Parylene test structures have already undergone an accelerated lifetime test and results have been analyzed.

  14. LAr calorimeter for SCC with a common vacuum bulkhead---a concept to improve hermeticity

    SciTech Connect

    Pope, W.L. ); Watt, R.D. )

    1989-11-01

    A new concept for a Barrel/Endcap LAr Calorimeter (LAC) is described in which the Barrel and Endcaps are in separate vacuum enclosures but share a common vacuum bulkhead (CVB). We explore 2 possible bulkhead construction types; welded plate sandwich panels, and brazed sandwich panels in which the core is an isotropic cellular solid--foamed aluminum. Gas lines and electric cables from he innermost Drift Chamber pass through radial holes in the core of the sandwich bulkhead. The CVB concept offers the potential to obtain a more hermetic calorimeter with significantly reduced dead material and/or space in the interface region common to conventional design LAr detectors for the SSC with Endcap features. To utilize a common additional steps to remove the Drift Chamber, a large increase in Endcap standby heat leak, and perhaps, new cryogenic safety issues. We find that significant amount of dead mass can be removed from critical regions of the vacuum shells when compared to a promising SSC LAC reference design. It is also shown that the increased standby heat leak of this concept can be easily removed by existing cooling capacity in another large LAr calorimeter. It is further shown that shut-downs need not be appreciably longer. Finally, it is argued that cryogen spill hazards can be avoided if the Endcap's LAr is removed during Drift chamber maintenance shutdowns, and that cryogenic safety is not compromised.

  15. A new model for vacuum quality and lifetime prediction in hermetic vacuum bonded MEMS

    NASA Astrophysics Data System (ADS)

    Bonucci, A.; Guadagnuolo, S.; Caterino, A.; Conte, A.; Moraja, M.

    2008-02-01

    In many MEMS applications the level of vacuum is a key issue as it directly affects the quality of the device, in terms of response reliability. Due to the unavoidable desorption phenomena of gaseous species from the internal surfaces, the vacuum inside a MEMS, after bonding encapsulation, tends to be degraded, unless a proper getter solution is applied. The in situ getter film (PaGeWafer®) is recognised to be the most reliable way to get rid of degassed species, assuring uniform, high quality performances of the device throughout the lifetime. Moreover, post process vacuum quality control and reliability for hermetic bonding is extremely important for overall device reliability and process yield. In this paper we will discuss the main factors that are critical in the attainment of vacuum and will present a novel calculation model that enables the prediction of vacuum level after bonding, making also possible the estimate of the lifetime. Furthermore, a new analytical method based on the residual gas analyses (RGA) will be presented that gives the main characteristics of the materials. Modeling and simulation work support the process optimization and system design.

  16. Detail view of unit 43 with high pressure stage compressor ...

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

    Detail view of unit 43 with high pressure stage compressor in left foreground and low pressure stage compressor in right background. - Burnsville Natural Gas Pumping Station, Saratoga Avenue between Little Kanawha River & C&O Railroad line, Burnsville, Braxton County, WV

  17. 46 CFR 197.310 - Air compressor system.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 7 2011-10-01 2011-10-01 false Air compressor system. 197.310 Section 197.310 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE OCCUPATIONAL SAFETY AND HEALTH STANDARDS GENERAL PROVISIONS Commercial Diving Operations Equipment § 197.310 Air compressor system. A...

  18. 30 CFR 57.13017 - Compressor discharge pipes.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Compressor discharge pipes. 57.13017 Section 57.13017 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-UNDERGROUND METAL AND NONMETAL MINES Compressed Air and Boilers § 57.13017 Compressor...

  19. 30 CFR 56.13017 - Compressor discharge pipes.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Compressor discharge pipes. 56.13017 Section 56.13017 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-SURFACE METAL AND NONMETAL MINES Compressed Air and Boilers § 56.13017 Compressor...

  20. 30 CFR 57.13017 - Compressor discharge pipes.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Compressor discharge pipes. 57.13017 Section 57.13017 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-UNDERGROUND METAL AND NONMETAL MINES Compressed Air and Boilers § 57.13017 Compressor...

  1. 30 CFR 56.13017 - Compressor discharge pipes.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Compressor discharge pipes. 56.13017 Section 56.13017 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-SURFACE METAL AND NONMETAL MINES Compressed Air and Boilers § 56.13017 Compressor...

  2. Axial and Centrifugal Compressor Mean Line Flow Analysis Method

    NASA Technical Reports Server (NTRS)

    Veres, Joseph P.

    2009-01-01

    This paper describes a method to estimate key aerodynamic parameters of single and multistage axial and centrifugal compressors. This mean-line compressor code COMDES provides the capability of sizing single and multistage compressors quickly during the conceptual design process. Based on the compressible fluid flow equations and the Euler equation, the code can estimate rotor inlet and exit blade angles when run in the design mode. The design point rotor efficiency and stator losses are inputs to the code, and are modeled at off design. When run in the off-design analysis mode, it can be used to generate performance maps based on simple models for losses due to rotor incidence and inlet guide vane reset angle. The code can provide an improved understanding of basic aerodynamic parameters such as diffusion factor, loading levels and incidence, when matching multistage compressor blade rows at design and at part-speed operation. Rotor loading levels and relative velocity ratio are correlated to the onset of compressor surge. NASA Stage 37 and the three-stage NASA 74-A axial compressors were analyzed and the results compared to test data. The code has been used to generate the performance map for the NASA 76-B three-stage axial compressor featuring variable geometry. The compressor stages were aerodynamically matched at off-design speeds by adjusting the variable inlet guide vane and variable stator geometry angles to control the rotor diffusion factor and incidence angles.

  3. 40 CFR 61.242-3 - Standards: Compressors.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... under 40 CFR part 60, shall not be in VOC service. (d) Each barrier fluid system as described in... Leaks (Fugitive Emission Sources) § 61.242-3 Standards: Compressors. (a) Each compressor shall be... both based on the criterion determined under paragraph (e)(2) of this section, a leak is detected....

  4. View of the compressor inside of Feature 14, looking southeast ...

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

    View of the compressor inside of Feature 14, looking southeast from the doorway on the northwest wall of the compressor shed - Orphan Lode Mine, North of West Rim Road between Powell Point and Maricopa Point, South Rim, Grand Canyon Village, Coconino County, AZ

  5. 49 CFR 192.163 - Compressor stations: Design and construction.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... minimize the possibility of fire being communicated to the compressor building from structures on adjacent... fire-fighting equipment. (b) Building construction. Each building on a compressor station site must be... escape and an unobstructed passage to a place of safety. Each door latch on an exit must be of a...

  6. 49 CFR 192.163 - Compressor stations: Design and construction.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... minimize the possibility of fire being communicated to the compressor building from structures on adjacent... fire-fighting equipment. (b) Building construction. Each building on a compressor station site must be... escape and an unobstructed passage to a place of safety. Each door latch on an exit must be of a...

  7. 14. VIEW OF AIR COMPRESSOR. 1500 kw Westinghouse AC generator ...

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

    14. VIEW OF AIR COMPRESSOR. 1500 kw Westinghouse AC generator steam-turbine unit; beyond is air compressor of Chicago Pneumatic Tool Company, 1920, engineered by Earl E. Know Company, Erie, Pennsylvania. - Juniata Shops, Power Plant & Boiler House, East of Fourth Avenue at Second Street, Altoona, Blair County, PA

  8. [Lubricant-free piston compressors for mechanized medical instruments].

    PubMed

    Sabitov, V Kh; Repin, V A; Kil'kinov, A A

    1988-01-01

    Piston compressor without lubrication with air blow to packing rings by plunger, disposed in subpiston space, is recommended as the basic scheme of construction of a power supply unit for medical pneumatic tooling. The construction reduces a leak of the compressive medium, increasing the efficiency of a compressor and seal reliability.

  9. Inspection and evaluation of 33-size compressor blades

    SciTech Connect

    Rafferty, M.J.

    1986-11-14

    The blades from ten 33-size compressors were inspected during FY 1986. The cracking incidence observed in this sample of approximately 9800 blades was very low. Only twelve cracked blades were found and nine of the twelve came from only two compressors. Eighteen additional blades had porosity formations which, during initial inspection, looked like cracks.

  10. Compressor Study to Meet Large Civil Tilt Rotor Engine Requirements

    NASA Technical Reports Server (NTRS)

    Veres, Joseph P.

    2009-01-01

    A vehicle concept study has been made to meet the requirements of the Large Civil Tilt Rotorcraft vehicle mission. A vehicle concept was determined, and a notional turboshaft engine system study was conducted. The engine study defined requirements for the major engine components, including the compressor. The compressor design-point goal was to deliver a pressure ratio of 31:1 at an inlet weight flow of 28.4 lbm/sec. To perform a conceptual design of two potential compressor configurations to meet the design requirement, a mean-line compressor flow analysis and design code were used. The first configuration is an eight-stage axial compressor. Some challenges of the all-axial compressor are the small blade spans of the rear-block stages being 0.28 in., resulting in the last-stage blade tip clearance-to-span ratio of 2.4 percent. The second configuration is a seven-stage axial compressor, with a centrifugal stage having a 0.28-in. impeller-exit blade span. The compressors conceptual designs helped estimate the flow path dimensions, rotor leading and trailing edge blade angles, flow conditions, and velocity triangles for each stage.

  11. Compressor Study to Meet Large Civil Tilt Rotor Engine Requirements

    NASA Technical Reports Server (NTRS)

    Veres, Joseph P.

    2009-01-01

    A vehicle concept study has been made to meet the requirements of the Large Civil Tilt Rotorcraft vehicle mission. A vehicle concept was determined, and a notional turboshaft engine system study was conducted. The engine study defined requirements for the major engine components, including the compressor. The compressor design-point goal was to deliver a pressure ratio of 31:1 at an inlet weight flow of 28.4 lbm/sec. To perform a conceptual design of two potential compressor configurations to meet the design requirement, a mean-line compressor flow analysis and design code were used. The first configuration is an eight-stage axial compressor. Some challenges of the all-axial compressor are the small blade spans of the rear-block stages being 0.28 in., resulting in the last-stage blade tip clearance-to-span ratio of 2.4%. The second configuration is a seven-stage axial compressor, with a centrifugal stage having a 0.28-in. impeller-exit blade span. The compressors conceptual designs helped estimate the flow path dimensions, rotor leading and trailing edge blade angles, flow conditions, and velocity triangles for each stage.

  12. 21 CFR 868.6250 - Portable air compressor.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Miscellaneous § 868.6250 Portable air compressor. (a) Identification. A portable air compressor is a device intended to provide compressed air for medical purposes, e.g., to drive ventilators and other respiratory devices. (b) Classification. Class II...

  13. 46 CFR 154.534 - Cargo pumps and cargo compressors.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 5 2010-10-01 2010-10-01 false Cargo pumps and cargo compressors. 154.534 Section 154.534 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CERTAIN BULK DANGEROUS CARGOES... Equipment Cargo and Process Piping Systems § 154.534 Cargo pumps and cargo compressors. Cargo pumps...

  14. 46 CFR 154.534 - Cargo pumps and cargo compressors.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 5 2013-10-01 2013-10-01 false Cargo pumps and cargo compressors. 154.534 Section 154.534 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CERTAIN BULK DANGEROUS CARGOES... Equipment Cargo and Process Piping Systems § 154.534 Cargo pumps and cargo compressors. Cargo pumps...

  15. 46 CFR 154.534 - Cargo pumps and cargo compressors.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 5 2012-10-01 2012-10-01 false Cargo pumps and cargo compressors. 154.534 Section 154.534 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CERTAIN BULK DANGEROUS CARGOES... Equipment Cargo and Process Piping Systems § 154.534 Cargo pumps and cargo compressors. Cargo pumps...

  16. 46 CFR 154.534 - Cargo pumps and cargo compressors.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 5 2014-10-01 2014-10-01 false Cargo pumps and cargo compressors. 154.534 Section 154.534 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CERTAIN BULK DANGEROUS CARGOES... Equipment Cargo and Process Piping Systems § 154.534 Cargo pumps and cargo compressors. Cargo pumps...

  17. 46 CFR 154.534 - Cargo pumps and cargo compressors.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 5 2011-10-01 2011-10-01 false Cargo pumps and cargo compressors. 154.534 Section 154.534 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CERTAIN BULK DANGEROUS CARGOES... Equipment Cargo and Process Piping Systems § 154.534 Cargo pumps and cargo compressors. Cargo pumps...

  18. 49 CFR 230.71 - Orifice testing of compressors.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... Compressor size Single strokes per minute Diameter of orifice(in inches) Air pressure maintained(in pounds... in altitude. (2) For compressors not listed in the table in paragraph (b)(1) of this section, the air pressure to be maintained shall be no less than 80 percent of the manufacturer's rated capacity for...

  19. 49 CFR 230.71 - Orifice testing of compressors.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... Compressor size Single strokes per minute Diameter of orifice(in inches) Air pressure maintained(in pounds... in altitude. (2) For compressors not listed in the table in paragraph (b)(1) of this section, the air pressure to be maintained shall be no less than 80 percent of the manufacturer's rated capacity for...

  20. 49 CFR 230.71 - Orifice testing of compressors.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... Compressor size Single strokes per minute Diameter of orifice(in inches) Air pressure maintained(in pounds... in altitude. (2) For compressors not listed in the table in paragraph (b)(1) of this section, the air pressure to be maintained shall be no less than 80 percent of the manufacturer's rated capacity for...

  1. 49 CFR 230.71 - Orifice testing of compressors.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... Compressor size Single strokes per minute Diameter of orifice(in inches) Air pressure maintained(in pounds... in altitude. (2) For compressors not listed in the table in paragraph (b)(1) of this section, the air pressure to be maintained shall be no less than 80 percent of the manufacturer's rated capacity for...

  2. 49 CFR 230.71 - Orifice testing of compressors.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... Compressor size Single strokes per minute Diameter of orifice(in inches) Air pressure maintained(in pounds... in altitude. (2) For compressors not listed in the table in paragraph (b)(1) of this section, the air pressure to be maintained shall be no less than 80 percent of the manufacturer's rated capacity for...

  3. 49 CFR 192.169 - Compressor stations: Pressure limiting devices.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... compressor station must extend to a location where the gas may be discharged without hazard. ... 49 Transportation 3 2010-10-01 2010-10-01 false Compressor stations: Pressure limiting devices... SAFETY TRANSPORTATION OF NATURAL AND OTHER GAS BY PIPELINE: MINIMUM FEDERAL SAFETY STANDARDS Design...

  4. 49 CFR 192.169 - Compressor stations: Pressure limiting devices.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... compressor station must extend to a location where the gas may be discharged without hazard. ... 49 Transportation 3 2011-10-01 2011-10-01 false Compressor stations: Pressure limiting devices... SAFETY TRANSPORTATION OF NATURAL AND OTHER GAS BY PIPELINE: MINIMUM FEDERAL SAFETY STANDARDS Design...

  5. 49 CFR 192.165 - Compressor stations: Liquid removal.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 3 2011-10-01 2011-10-01 false Compressor stations: Liquid removal. 192.165... Components § 192.165 Compressor stations: Liquid removal. (a) Where entrained vapors in gas may liquefy under... introduction of those liquids in quantities that could cause damage. (b) Each liquid separator used to...

  6. 49 CFR 192.165 - Compressor stations: Liquid removal.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 3 2014-10-01 2014-10-01 false Compressor stations: Liquid removal. 192.165... Components § 192.165 Compressor stations: Liquid removal. (a) Where entrained vapors in gas may liquefy under... introduction of those liquids in quantities that could cause damage. (b) Each liquid separator used to...

  7. 49 CFR 192.165 - Compressor stations: Liquid removal.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 3 2012-10-01 2012-10-01 false Compressor stations: Liquid removal. 192.165... Components § 192.165 Compressor stations: Liquid removal. (a) Where entrained vapors in gas may liquefy under... introduction of those liquids in quantities that could cause damage. (b) Each liquid separator used to...

  8. CO2 compressor vibration and cause analysis

    NASA Technical Reports Server (NTRS)

    Ying, Y. L.

    1985-01-01

    The operational experience of a large turbine drive carbon dioxide compressor train in a urea plant with capacity of 1620 tons/day is considered. After the initial start-up in 1976, the vibration in the HP cylinder was comparatively serious. The radial vibration reached 4.2 to 4.5 mils and fluctuated around this value. It was attributed to the rotating stall based on the spectrum analysis. Additional return line from the 4th to 4th and higher temperature of the 4th inlet has cured the vibration. Problems are described which were encountered in the operation along with their solutions, and/or improvements.

  9. Piston-Skirt Lubrication System For Compressor

    NASA Technical Reports Server (NTRS)

    Schroeder, Edgar C.; Burzynski, Marion, Jr.

    1994-01-01

    Piston-skirt lubrication system provides steady supply of oil to piston rings of gas compressor. No need for oil-filled crankcase or external oil pump. Instead, part of each piston acts as its own oil pump circulating oil from reservoir. Annular space at bottom of piston and cylinder constitutes working volume of small oil pump. Depending on application, reservoir open to atmosphere, or sealed and pressurized in bellows to prevent contact between oil and atmosphere. Filter removes particles worn away from piston rings and cylinder wall during normal operation.

  10. Evolution of indirect reciprocity in groups of various sizes and comparison with direct reciprocity.

    PubMed

    Suzuki, Shinsuke; Akiyama, Eizo

    2007-04-01

    Recently many studies have investigated the evolution of indirect reciprocity through which cooperative action is returned by a third individual, e.g. individual A helped B and then receives help from C. Most studies on indirect reciprocity have presumed that only two individuals take part in a single interaction (group), e.g. A helps B and C helps A. In this paper, we investigate the evolution of indirect reciprocity when more than two individuals take part in a single group, and compare the result with direct reciprocity through which cooperative action is directly returned by the recipient. Our analyses show the following. In the population with discriminating cooperators and unconditional defectors, whether implementation error is included or not, (i) both strategies are evolutionarily stable and the evolution of indirect reciprocity becomes more difficult as group size increases, and (ii) the condition for the evolution of indirect reciprocity under standing reputation criterion where the third individuals distinguish between justified and unjustified defections is more relaxed than that under image scoring reputation criterion in which the third individuals do not distinguish with. Furthermore, in the population that also includes unconditional cooperators, (iii) in the presence of errors in implementation, the discriminating strategy is evolutionarily stable not only under standing but also under image scoring if group size is larger than two. Finally, (iv) in the absence of errors in implementation, the condition for the evolution of direct reciprocity is equivalent to that for the evolution of indirect reciprocity under standing, and, in the presence of errors, the condition for the evolution of direct reciprocity is very close to that for the evolution of indirect reciprocity under image scoring.

  11. Laser assisted and hermetic room temperature bonding based on direct bonding technology

    NASA Astrophysics Data System (ADS)

    Haneveld, Jeroen; Tijssen, Peter; Oonk, Johannes; Olde Riekerink, Mark; Tigelaar, Hildebrand; van't Oever, Ronny; Blom, Marko

    2014-03-01

    A novel method for laser assisted room temperature bonding of two substrates is presented. The method enables the packaging of delicate (bio)structures and/or finished (MEMS) devices, as there is no need for a high temperature annealing process. This also allows the bonding of two substrates with non-matching thermal expansion coefficients. The basis of the presented technology is the ability to create a direct pre-bond between two substrates. These can be two glass substrates, of which one has a thin film metal coating (e.g. Cr. Ti, Ta, Au…), or a silicon-glass combination. After (aligned) pre-bonding of the two wafers, a laser (e.g. a Nd:YAG laser) is used to form a permanent bond line on the bond interface, using the metal layer as a light absorber (or the silicon, in the case of a glass-silicon combination). The permanent bond line width is in the order of 10-50μm. The use of a laser to form the permanent bond ensures a hermetic sealing of the total package; a distinctive advantage over other, more conventional methods of room temperature bonding (e.g. adhesive bonding). He-leak testing showed leak rates in the order of 10-9 mbar l/s. This meets the failure criteria of the MIL-STD-883H standard of 5x10-8 mbar l/s. An added functionality of the proposed method is the possibility to create electrical circuitry on the bond interface, using the laser to modify the metal interlayer, rendering it electrically non-conductive. Biocompatible packages are also possible, by choosing the appropriate interlayer material. This would allow for the fabrication of implantable packages.

  12. Mechanical robustness of cryogenic temperature sensors packaged in a flat, hermetically-sealed package

    NASA Astrophysics Data System (ADS)

    Courts, S. S.

    2015-12-01

    Much of the work to develop internationally recognized temperature scales over the past 50 years was performed with thermometers whose sensing elements were constructed from platinum wire, rhodium-iron wire, or doped germanium elements. For high stability, the best results were obtained when the sensing element was strain-free mounted which reduced the effects of temperature-induced mechanical stress and deformation. Unfortunately, the devices were still highly susceptible to mechanical damage, and, barring a catastrophic mechanical shock, damage to the temperature sensors could go unnoticed as it could continue to operate with degraded accuracy. While not at the same level of stability as standards grade thermometers, many of the most commonly used cryogenic thermometers today are far more resistant to mechanical handling. This work examines the calibration offsets on three models of cryogenic temperature sensors resulting from mechanical shock and vibration. The models tested in this work were all obtained from Lake Shore Cryotronics, Inc., and included Cemox™ resistance thermometer models CX-1050-SD and CX-1050-AA, and a diode temperature sensor model DT-670-SD. Mechanical treatments were performed via a simple drop test (heights 20 cm, 50 cm, 1 m, and 4 m), random vibration per MIL-STD-202, Method 214, Table 2, Condition H, and mechanical shock per MIL-STD-883, Method 2002, Condition B. Each sensor was calibrated pre- and post-mechanical treatment and the effect of the treatment on each test sensor was quantified in terms of the equivalent temperature calibration shift. This work details the calibration shift of each sensor type following each treatment type over the 1.4 K to 325 K temperature range. No effects from the testing were discemable for Cemox and diode sensors packaged in the -SD package, a flat, hermetically sealed package, while small calibration offsets of less than 0.15% of temperature at higher temperatures were observed for Cemox sensors

  13. Three-person game facilitates indirect reciprocity under image scoring.

    PubMed

    Suzuki, Shinsuke; Akiyama, Eizo

    2007-11-01

    Reputation building plays an important role in the evolution of reciprocal altruism when the same individuals do not interact repeatedly because, by referring to reputation, a reciprocator can know which partners are cooperative and can reciprocate with a cooperator. This reciprocity based on reputation is called indirect reciprocity. Previous studies of indirect reciprocity have focused only on two-person games in which only two individuals participate in a single interaction, and have claimed that indirectly reciprocal cooperation cannot be established under image scoring reputation criterion where the reputation of an individual who has cooperated (defected) becomes good (bad). In this study, we specifically examine three-person games, and reveal that indirectly reciprocal cooperation can be formed and maintained stably, even under image scoring, by a nucleus shield mechanism. In the nucleus shield, reciprocators are a shield that keeps out unconditional defectors, whereas unconditional cooperators are the backbone of cooperation that retains a good reputation among the population.

  14. Compressor Stability Enhancement Using Discrete Tip Injection

    NASA Technical Reports Server (NTRS)

    Suder, Kenneth L.; Hathaway, Michael D.; Thorp, Scott A.; Strazisar, Anthony J.; Bright, Michelle B.

    2001-01-01

    Mass injection upstream of the tip of a high-speed axial compressor rotor is a stability enhancement approach known to be effective in suppressing small in tip-critical rotors. This process is examined in a transonic axial compressor rotor through experiments and time-averaged Navier-Stokes CFD simulations. Measurements and simulations for discrete injection are presented for a range of injection rates and distributions of injectors around the annulus. The simulations indicate that tip injection increases stability by unloading the rotor tip and that increasing injection velocity improves the effectiveness of tip injection. For the tested rotor, experimental results demonstrate that at 70 percent speed the stalling flow coefficient can be reduced by 30 percent using an injected mass- flow equivalent to 1 percent of the annulus flow. At design speed, the stalling flow coefficient was reduced by 6 percent using an injected mass-fiow equivalent to 2 percent of the annulus flow. The experiments show that stability enhancement is related to the mass-averaged axial velocity at the tip. For a given injected mass-flow, the mass-averaged axial velocity at the tip is increased by injecting flow over discrete portions of the circumference as opposed to full-annular injection. The implications of these results on the design of recirculating casing treatments and other methods to enhance stability will be discussed.

  15. Testing and optimizing active rotary flux compressors

    SciTech Connect

    Carder, B.M.; Eimerl, D.; Goodwin, E.J.; Trenholme, J.; Foley, R.J.; Bird, W.L.

    1981-06-01

    The test program for an Active Rotary Flux Compressor (ARFC) has demonstrated conclusively that large compression factors can be obtained with a laminated-iron, wave-wound, rotary flux compressor. Peak-current to startup-current ratios of 17 have been produced with a rotor tip speed of 60 meters per second. Sub-millisecond pulse widths were also measured: the minimum, 590 ..mu..sec (FWHM), was obtained at 5607 rpm with an 8-inch diameter, 4-pole rotor. The machine was operated without a high current output switch, proving the feasibility of a novel commutation scheme described. A computational code has been developed that will calculate the output waveshape of the model ARFC with reasonable accuracy. The code is being refined to better account for saturation in the iron laminations. A second optimization code selects the best design for a given application. This code shows favorable cost effectiveness of large ARFC's over the conventional capacitors to drive flashlamps for large lasers.

  16. Impulsive Injection for Compressor Stator Separation Control

    NASA Technical Reports Server (NTRS)

    Culley, Dennis E.; Braunscheidel, Edward P.; Bright, Michelle M.

    2005-01-01

    Flow control using impulsive injection from the suction surface of a stator vane has been applied in a low speed axial compressor. Impulsive injection is shown to significantly reduce separation relative to steady injection for vanes that were induced to separate by an increase in vane stagger angle of 4 degrees. Injected flow was applied to the airfoil suction surface using spanwise slots pitched in the streamwise direction. Injection was limited to the near-hub region, from 10 to 36 percent of span, to affect the dominant loss due to hub leakage flow. Actuation was provided externally using high-speed solenoid valves closely coupled to the vane tip. Variations in injected mass, frequency, and duty cycle are explored. The local corrected total pressure loss across the vane at the lower span region was reduced by over 20 percent. Additionally, low momentum fluid migrating from the hub region toward the tip was effectively suppressed resulting in an overall benefit which reduced corrected area averaged loss through the passage by 4 percent. The injection mass fraction used for impulsive actuation was typically less than 0.1 percent of the compressor through flow.

  17. High Efficiency Centrifugal Compressor for Rotorcraft Applications

    NASA Technical Reports Server (NTRS)

    Medic, Gorazd; Sharma, Om P.; Jongwook, Joo; Hardin, Larry W.; McCormick, Duane C.; Cousins, William T.; Lurie, Elizabeth A.; Shabbir, Aamir; Holley, Brian M.; Van Slooten, Paul R.

    2014-01-01

    The report "High Efficiency Centrifugal Compressor for Rotorcraft Applications" documents the work conducted at UTRC under the NRA Contract NNC08CB03C, with cost share 2/3 NASA, and 1/3 UTRC, that has been extended to 4.5 years. The purpose of this effort was to identify key technical barriers to advancing the state-of-the-art of small centrifugal compressor stages; to delineate the measurements required to provide insight into the flow physics of the technical barriers; to design, fabricate, install, and test a state-of-the-art research compressor that is representative of the rear stage of an axial-centrifugal aero-engine; and to acquire detailed aerodynamic performance and research quality data to clarify flow physics and to establish detailed data sets for future application. The design activity centered on meeting the goal set outlined in the NASA solicitation-the design target was to increase efficiency at higher work factor, while also reducing the maximum diameter of the stage. To fit within the existing Small Engine Components Test Facility at NASA Glenn Research Center (GRC) and to facilitate component re-use, certain key design parameters were fixed by UTRC, including impeller tip diameter, impeller rotational speed, and impeller inlet hub and shroud radii. This report describes the design effort of the High Efficiency Centrifugal Compressor stage (HECC) and delineation of measurements, fabrication of the compressor, and the initial tests that were performed. A new High-Efficiency Centrifugal Compressor stage with a very challenging reduction in radius ratio was successfully designed, fabricated and installed at GRC. The testing was successful, with no mechanical problems and the running clearances were achieved without impeller rubs. Overall, measured pressure ratio of 4.68, work factor of 0.81, and at design exit corrected flow rate of 3 lbm/s met the target requirements. Polytropic efficiency of 85.5 percent and stall margin of 7.5 percent were

  18. Axial compressor middle stage secondary flow study

    NASA Technical Reports Server (NTRS)

    Wagner, J. H.; Dring, R. P.; Joslyn, H. D.

    1983-01-01

    This report describes an experimental investigation of the secondary flow within and aft of an axial compressor model with thick endwall boundary layers. The objective of the study was to obtain detailed aerodynamic and trace gas concentration traverse data aft of a well documented isolated rotor for the ultimate purpose of improving the design phases of compressor development based on an improved physical understanding of secondary flow. It was determined from the flow visualization, aerodynamic, and trace gas concentration results that the relative unloading of the midspan region of the airfoil inhibitied a fullspan separation at high loading preventing the massive radial displacement of the hub corner stall to the tip. Radial distribution of high and low total pressure fluid influenced the magnitude of the spanwise distribution of loss, such that, there was a general decreases in loss near the hub to the extent that for the least loaded case a negative loss (increase in total pressure) was observed. The ability to determine the spanwise distribution of blockage was demonstrated. Large blockage was present in the endwall regions due to the corner stall and tip leakage with little blockage in the core flow region. Hub blockage was found to increase rapidly with loading.

  19. Measuring and making decisions for social reciprocity.

    PubMed

    Solanas, Antonio; Leiva, David; Sierra, Vicenta; Salafranca, Lluís

    2009-08-01

    Social reciprocity may explain certain emerging psychological processes likely to be founded on dyadic relations. Although indexes and statistics have been proposed to measure and make statistical decisions regarding social reciprocity in groups, these tools were generally developed to identify association patterns rather than to quantify the discrepancies between what each individual addresses to his or her partners and what is received from those partners in return. Additionally, social researchers' interest extends beyond measuring groups at the global level because dyadic and individual measurements are also necessary for proper descriptions of social interactions. This study is concerned with a new statistic for measuring social reciprocity at the global level and with decomposing that statistic in order to identify which dyads and individuals account for a significant part of asymmetry in social interactions. In addition to a set of indexes, some exact analytical results are derived, and a way of making statistical decisions is proposed.

  20. Theory of reciprocating contact for viscoelastic solids

    NASA Astrophysics Data System (ADS)

    Putignano, Carmine; Carbone, Giuseppe; Dini, Daniele

    2016-04-01

    A theory of reciprocating contacts for linear viscoelastic materials is presented. Results are discussed for the case of a rigid sphere sinusoidally driven in sliding contact with a viscoelastic half-space. Depending on the size of the contact, the frequency and amplitude of the reciprocating motion, and on the relaxation time of the viscoelastic body, we establish that the contact behavior may range from the steady-state viscoelastic solution, in which traction forces always oppose the direction of the sliding rigid punch, to a more elaborate trend, which is due to the strong interaction between different regions of the path covered during the reciprocating motion. Practical implications span a number of applications, ranging from seismic engineering to biotechnology.

  1. Gauge invariance and reciprocity in quantum mechanics

    SciTech Connect

    Leung, P. T.; Young, K.

    2010-03-15

    Reciprocity in wave propagation usually refers to the symmetry of the Green's function under the interchange of the source and the observer coordinates, but this condition is not gauge invariant in quantum mechanics, a problem that is particularly significant in the presence of a vector potential. Several possible alternative criteria are given and analyzed with reference to different examples with nonzero magnetic fields and/or vector potentials, including the case of a multiply connected spatial domain. It is shown that the appropriate reciprocity criterion allows for specific phase factors separable into functions of the source and observer coordinates and that this condition is robust with respect to the addition of any scalar potential. In the Aharonov-Bohm effect, reciprocity beyond monoenergetic experiments holds only because of subsidiary conditions satisfied in actual experiments: the test charge is in units of e and the flux is produced by a condensate of particles with charge 2e.

  2. Reciprocating Feed System Development Status

    NASA Technical Reports Server (NTRS)

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

    2005-01-01

    The reciprocating feed system (RFS) is an alternative means of providing high pressure propellant flow at low cost and system mass, with high fail-operational reliability. The RFS functions by storing the liquid propellants in large, low-pressure tanks and then expelling each propellant through two or three small, high-pressure tanks. Each RFS tank is sequentially filled, pressurized, expelled, vented, and refilled so as to provide a constant, or variable, mass flow rate to the engine. This type of system is much lighter than a conventional pressure fed system in part due to the greatly reduced amount of inert tank weight. The delivered payload for an RFS is superior to that of conventional pressure fed systems for conditions of high total impulse and it is competitive with turbopump systems, up to approximately 2000 psi. An advanced version of the RFS uses autogenous pressurization and thrust augmentation to achieve higher performance. In this version, the pressurization gases are combusted in a small engine, thus making the pressurization system, in effect, part of the propulsion system. The RFS appears to be much less expensive than a turbopump system, due to reduced research and development cost and hardware cost, since it is basically composed of small high- pressure tanks, a pressurization system, and control valves. A major benefit is the high reliability fail-operational mode; in the event of a failure in one of the three tank-systems, it can operate on the two remaining tanks. Other benefits include variable pressure and flow rates, ease of engine restart in micro-gravity, and enhanced propellant acquisition and control under adverse acceleration conditions. We present a system mass analysis tool that accepts user inputs for various design and mission parameters and calculates such output values payload and vehicle weights for the conventional pressure fed system, the RFS, the Autogenous Pressurization Thrust Augmentation (APTA) RFS, and turbopump systems

  3. Evolution of cooperation by generalized reciprocity

    PubMed Central

    Pfeiffer, Thomas; Rutte, Claudia; Killingback, Timothy; Taborsky, Michael; Bonhoeffer, Sebastian

    2005-01-01

    The evolution of cooperation by direct reciprocity requires that individuals recognize their present partner and remember the outcome of their last encounter with that specific partner. Direct reciprocity thus requires advanced cognitive abilities. Here, we demonstrate that if individuals repeatedly interact within small groups with different partners in a two person Prisoner's Dilemma, cooperation can emerge and also be maintained in the absence of such cognitive capabilities. It is sufficient for an individual to base their decision of whether or not to cooperate on the outcome of their last encounter—even if it was with a different partner. PMID:16024372

  4. Feasibility analysis of reciprocating magnetic heat pumps

    NASA Technical Reports Server (NTRS)

    Larson, A. V.; Hartley, J. G.; Shelton, Sam V.; Smith, M. M.

    1989-01-01

    A reciprocating gadolinium core in a regeneration fluid column in the warm bore of a superconducting solenoidal magnet is considered for magnetic refrigeration in 3.517 MW (1000 ton) applications. A procedure is presented to minimize the amount of superconducting cable needed in the magnet design. Estimated system capital costs for an ideal magnetic refrigerator of this type become comparable to conventional chillers as the frequency of reciprocation approaches 10 Hertz. A 1-D finite difference analysis of a regenerator cycling at 0.027 Hertz is presented which exhibits some of the features seen in the experiments of G. V. Brown.

  5. Testing and failure analysis to improve screening techniques for hermetically sealed metallized film capacitors for low energy applications

    NASA Technical Reports Server (NTRS)

    1982-01-01

    Effective screening techniques are evaluated for detecting insulation resistance degradation and failure in hermetically sealed metallized film capacitors used in applications where low capacitor voltage and energy levels are common to the circuitry. A special test and monitoring system capable of rapidly scanning all test capacitors and recording faults and/or failures is examined. Tests include temperature cycling and storage as well as low, medium, and high voltage life tests. Polysulfone film capacitors are more heat stable and reliable than polycarbonate film units.

  6. From Born Reciprocity to Reciprocal Relativity: A Paradigm for Space-Time Physics

    NASA Astrophysics Data System (ADS)

    Jarvis, Peter

    Born's principle of reciprocity -- the exchangeability of relativistic energy-momentum and time-position -- can be seen as a discrete element of a continuous group of symmetry transformations which transcend relativity. Invariance under the semi-direct product of the Weyl-Heisenberg group H(4) of canonical commutation relations with the non-compact unitary group U(3, 1) -- the so-called quaplectic group U(3, 1) ⋉ H(4) -- has been considered by Low as an extension of Born reciprocity to a fundamental symmetry principle of `reciprocal relativity' for the physics of non-inertial frames and high energy processes...

  7. Core compressor exit stage study. 1: Aerodynamic and mechanical design

    NASA Technical Reports Server (NTRS)

    Burdsall, E. A.; Canal, E., Jr.; Lyons, K. A.

    1979-01-01

    The effect of aspect ratio on the performance of core compressor exit stages was demonstrated using two three stage, highly loaded, core compressors. Aspect ratio was identified as having a strong influence on compressors endwall loss. Both compressors simulated the last three stages of an advanced eight stage core compressor and were designed with the same 0.915 hub/tip ratio, 4.30 kg/sec (9.47 1bm/sec) inlet corrected flow, and 167 m/sec (547 ft/sec) corrected mean wheel speed. The first compressor had an aspect ratio of 0.81 and an overall pressure ratio of 1.357 at a design adiabatic efficiency of 88.3% with an average diffusion factor or 0.529. The aspect ratio of the second compressor was 1.22 with an overall pressure ratio of 1.324 at a design adiabatic efficiency of 88.7% with an average diffusion factor of 0.491.

  8. Pressure field study of the Tevatron cold compressors

    SciTech Connect

    Klebaner, A.L.; Martinez, A.; Soyars, W.M.; Theilacker, J.C.; /Fermilab

    2003-01-01

    The Fermilab Tevatron cryogenic system utilizes high-speed centrifugal cold compressors, manufactured by Ishikawajima-Harima Heavy Industries Co. Ltd. (IHI), for high-energy operations [1]. The compressor is designed to pump 60 g/sec of 3.6 K saturated helium vapor at a pressure ratio of 2.8, with an off-design range of 40 to 70 g/sec. Operating speeds are between 40 and 95 krpm, with a speed of 80 krpm at the design point. Different heat loads and magnet quench performance of each of the twenty-four satellite refrigerators dictates different process pressure and flow rates of the cold compressors. Reducing the process flow rate can cause the centrifugal cold compressor to stop pumping and subsequently surge. Tests have been conducted at the Cryogenic Test Facility at Fermilab to map the pressure field and appropriate efficiency of the IHI hydrodynamic cold compressor. The information allows tuning of each of the twenty-four Tevatron satellite refrigerators to avoid cold compressor operation near the surge and choke lines. A new impeller has also been tested. The Tevatron cold compressor pressure field and efficiency data with the new impeller are presented in this paper.

  9. Internal hysteresis experienced on a high pressure syn gas compressor

    NASA Technical Reports Server (NTRS)

    Zeidan, F. Y.

    1984-01-01

    A vibration instability phenomenon experienced in operating high pressure syn gas centrifugal compressors in two ammonia plants is described. The compressors were monitored by orbit and spectrum analysis for changes from baseline readings. It is found that internal hysteresis was the major destabilizing force; however, the problem was further complicated by seal lockup at the suction end of the compressor. A coupling lockup problem and a coupling fit problem, which frettage of the shaft, are also considered as contributors to the self excited vibrations.

  10. Study of compressor systems for a gas-generator engine

    NASA Technical Reports Server (NTRS)

    Sather, Bernard I; Tauschek, Max J

    1950-01-01

    Various methods of providing compressor-capacity and pressure-ratio control in the gas-generator type of compound engine over a range of altitudes from sea level to 50,000 feet are presented. The analytical results indicate that the best method of control is that in which the first stage of compression is carried out in a variable-speed supercharger driven by a hydraulic slip coupling. The constant-speed second stage could be either a mixed-flow rotary compressor or a piston-type compressor. A variable-area turbine nozzle is shown to be unnecessary for cruising operation of the engine.

  11. Some field experience with subsynchronous vibration of centrifugal compressors

    NASA Technical Reports Server (NTRS)

    Wang, Xi-Xuan; Gu, Jin-Chu; Shen, Qin-Gen; Hua, Yong-Li; Zhu, Lan-Sheng; Du, Yun-Tian

    1989-01-01

    A lot of large chemical fertilizer plants producing 1000 ton NH3/day and 1700 ton urea/day were constructed in the 1970's in China. During operation, subsynchronous vibration takes place occasionally in some of the large turbine-compressor sets and has resulted in heavy economic losses. Two cases of subsynchronous vibration are described: Self-excited vibration of the low-pressure (LP) cylinder of one kind of N2-H2 multistage compressor; and Forced subsynchronous vibration of the high-pressure (HP) cylinder of the CO2 compressor.

  12. Turbine Engine with Differential Gear Driven Fan and Compressor

    NASA Technical Reports Server (NTRS)

    Suciu, Gabriel L. (Inventor); Pagluica, Gino J. (Inventor); Duong, Loc Quang (Inventor); Portlock, Lawrence E. (Inventor)

    2013-01-01

    A gas turbine engine provides a differential gear system coupling the turbine to the bypass fan and the compressor. In this manner, the power/speed split between the bypass fan and the compressor can be optimized under all conditions. In the example shown, the turbine drives a sun gear, which drives a planet carrier and a ring gear in a differential manner. One of the planet carrier and the ring gear is coupled to the bypass fan, while the other is coupled to the compressor.

  13. Design and performance analysis of gas sorption compressors

    NASA Technical Reports Server (NTRS)

    Chan, C. K.

    1984-01-01

    Compressor kinetics based on gas adsorption and desorption processes by charcoal and for gas absorption and desorption processes by LaNi5 were analyzed using a two-phase model and a three-component model, respectively. The assumption of the modeling involved thermal and mechanical equilibria between phases or among the components. The analyses predicted performance well for compressors which have heaters located outside the adsorbent or the absorbent bed. For the rapidly-cycled compressor, where the heater was centrally located, only the transient pressure compared well with the experimental data.

  14. Microbunching Due to Coherent Synchrotron Radiation in a Bunch Compressor

    SciTech Connect

    Stupakov, Gennady

    2001-09-10

    The coherent synchrotron radiation of a bunch in a bunch compressor may lead to the microwave instability producing longitudinal modulation of the bunch. This modulation generates coherent radiation with the wave length small compared to the bunch length. It can also be a source of an undesirable emittance growth in the compressor. We derive and analyze the equation that describes linear evolution of the microwave modulation. Numerical solution of this equation for the LCLS bunch compressor reveals such an instability, in qualitative agreement with numerical simulations.

  15. 47 CFR 51.703 - Reciprocal compensation obligation of LECs.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 3 2010-10-01 2010-10-01 false Reciprocal compensation obligation of LECs. 51.703 Section 51.703 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES (CONTINUED) INTERCONNECTION Reciprocal Compensation for Transport and Termination...

  16. Development of Trust and Reciprocity in Adolescence

    ERIC Educational Resources Information Center

    van den Bos, Wouter; Westenberg, Michiel; van Dijk, Eric; Crone, Eveline A.

    2010-01-01

    We investigate the development of two types of prosocial behavior, trust and reciprocity, as defined using a game-theoretical task that allows investigation of real-time social interaction, among 4 age groups from 9 to 25 years. By manipulating the possible outcome alternatives, we could distinguish among important determinants of trust and…

  17. Cooperation under indirect reciprocity and imitative trust.

    PubMed

    Saavedra, Serguei; Smith, David; Reed-Tsochas, Felix

    2010-10-27

    Indirect reciprocity, a key concept in behavioral experiments and evolutionary game theory, provides a mechanism that allows reciprocal altruism to emerge in a population of self-regarding individuals even when repeated interactions between pairs of actors are unlikely. Recent empirical evidence show that humans typically follow complex assessment strategies involving both reciprocity and social imitation when making cooperative decisions. However, currently, we have no systematic understanding of how imitation, a mechanism that may also generate negative effects via a process of cumulative advantage, affects cooperation when repeated interactions are unlikely or information about a recipient's reputation is unavailable. Here we extend existing evolutionary models, which use an image score for reputation to track how individuals cooperate by contributing resources, by introducing a new imitative-trust score, which tracks whether actors have been the recipients of cooperation in the past. We show that imitative trust can co-exist with indirect reciprocity mechanisms up to a threshold and then cooperation reverses -revealing the elusive nature of cooperation. Moreover, we find that when information about a recipient's reputation is limited, trusting the action of third parties towards her (i.e. imitating) does favor a higher collective cooperation compared to random-trusting and share-alike mechanisms. We believe these results shed new light on the factors favoring social imitation as an adaptive mechanism in populations of cooperating social actors.

  18. Upstream reciprocity and the evolution of gratitude.

    PubMed

    Nowak, Martin A; Roch, Sébastien

    2007-03-01

    If someone is nice to you, you feel good and may be inclined to be nice to somebody else. This every day experience is borne out by experimental games: the recipients of an act of kindness are more likely to help in turn, even if the person who benefits from their generosity is somebody else. This behaviour, which has been called 'upstream reciprocity', appears to be a misdirected act of gratitude: you help somebody because somebody else has helped you. Does this make any sense from an evolutionary or a game theoretic perspective? In this paper, we show that upstream reciprocity alone does not lead to the evolution of cooperation, but it can evolve and increase the level of cooperation if it is linked to either direct or spatial reciprocity. We calculate the random walks of altruistic acts that are induced by upstream reciprocity. Our analysis shows that gratitude and other positive emotions, which increase the willingness to help others, can evolve in the competitive world of natural selection.

  19. Weak reciprocity alone cannot explain peer punishment.

    PubMed

    Casari, Marco

    2012-02-01

    The claims about (1) the lack of empirical support for a model of strong reciprocation and (2) the irrelevant empirical role of costly punishment to support cooperation in the field need qualifications. The interpretation of field evidence is not straightforward, and other-regarding preferences are also likely to play a role in the field.

  20. The Effects of Feedback as Interpersonal Reciprocities

    ERIC Educational Resources Information Center

    Levenstein, Joseph; And Others

    1977-01-01

    Tests the hypothesis that a response to a given feedback statement will be its reciprocal. In Phase 1, a pool of feedback statements was written and scaled along dimensions of power (dominance-submission) and affect (affection-hostility). In Phase 2, these statements were used as the basis for giving feedback and replying to it. (Author)

  1. 36 CFR 251.63 - Reciprocity.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 251.63 Parks, Forests, and Public Property FOREST SERVICE, DEPARTMENT OF AGRICULTURE LAND USES Special Uses § 251.63 Reciprocity. If it is determined that a right-of-way shall be needed by the United States... across Federal lands, the authorized officer may condition a special use authorization to require...

  2. 36 CFR 251.63 - Reciprocity.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 251.63 Parks, Forests, and Public Property FOREST SERVICE, DEPARTMENT OF AGRICULTURE LAND USES Special Uses § 251.63 Reciprocity. If it is determined that a right-of-way shall be needed by the United States... across Federal lands, the authorized officer may condition a special use authorization to require...

  3. 36 CFR 251.63 - Reciprocity.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 251.63 Parks, Forests, and Public Property FOREST SERVICE, DEPARTMENT OF AGRICULTURE LAND USES Special Uses § 251.63 Reciprocity. If it is determined that a right-of-way shall be needed by the United States... across Federal lands, the authorized officer may condition a special use authorization to require...

  4. 36 CFR 251.63 - Reciprocity.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 251.63 Parks, Forests, and Public Property FOREST SERVICE, DEPARTMENT OF AGRICULTURE LAND USES Special Uses § 251.63 Reciprocity. If it is determined that a right-of-way shall be needed by the United States... across Federal lands, the authorized officer may condition a special use authorization to require...

  5. 36 CFR 251.63 - Reciprocity.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 251.63 Parks, Forests, and Public Property FOREST SERVICE, DEPARTMENT OF AGRICULTURE LAND USES Special Uses § 251.63 Reciprocity. If it is determined that a right-of-way shall be needed by the United States... across Federal lands, the authorized officer may condition a special use authorization to require...

  6. 46 CFR 8.120 - Reciprocity.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... § 8.120 Reciprocity. (a) The Commandant may delegate authority to a classification society that has... in paragraph (a) of this section are satisfied, a classification society must provide to the Coast Guard an affidavit, from the government of the country that the classification society is...

  7. 46 CFR 8.120 - Reciprocity.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... § 8.120 Reciprocity. (a) The Commandant may delegate authority to a classification society that has... in paragraph (a) of this section are satisfied, a classification society must provide to the Coast Guard an affidavit, from the government of the country that the classification society is...

  8. Reciprocity in Preschool Peers' Social Interaction.

    ERIC Educational Resources Information Center

    Chiu, Jih-Perng Peter

    This study sought to describe the norms of reciprocity in social interaction from the viewpoint of immediate behavioral exchanges by examining the social interaction of preschool peers in a free-play situation. Seventeen 4-year-old children, eight girls and nine boys, were observed during free play activity periods after a picture sociometric test…

  9. 37 CFR 11.24 - Reciprocal discipline.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... case by clear and convincing evidence that the practitioner violated 37 CFR 10.23, as further identified under 37 CFR 10.23(c)(5), (or any successor regulation identifying such public censure, public... 37 Patents, Trademarks, and Copyrights 1 2010-07-01 2010-07-01 false Reciprocal discipline....

  10. 37 CFR 11.24 - Reciprocal discipline.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... case by clear and convincing evidence that the practitioner violated 37 CFR 10.23, as further identified under 37 CFR 10.23(c)(5), (or any successor regulation identifying such public censure, public... 37 Patents, Trademarks, and Copyrights 1 2012-07-01 2012-07-01 false Reciprocal discipline....

  11. 37 CFR 11.24 - Reciprocal discipline.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 37 Patents, Trademarks, and Copyrights 1 2014-07-01 2014-07-01 false Reciprocal discipline. 11.24... discipline. (a) Notification of OED Director. Within thirty days of being publicly censured, publicly... USPTO Director. The OED Director shall, in addition, without Committee on Discipline authorization,...

  12. 37 CFR 11.24 - Reciprocal discipline.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... case by clear and convincing evidence that the practitioner violated 37 CFR 10.23, as further identified under 37 CFR 10.23(c)(5), (or any successor regulation identifying such public censure, public... 37 Patents, Trademarks, and Copyrights 1 2011-07-01 2011-07-01 false Reciprocal discipline....

  13. 37 CFR 11.24 - Reciprocal discipline.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 37 Patents, Trademarks, and Copyrights 1 2013-07-01 2013-07-01 false Reciprocal discipline. 11.24... discipline. (a) Notification of OED Director. Within thirty days of being publicly censured, publicly... USPTO Director. The OED Director shall, in addition, without Committee on Discipline authorization,...

  14. Tuition Reciprocity in the United States

    ERIC Educational Resources Information Center

    Stewart, Gregory; Wright, Dianne Brown; Kennedy, Angelica

    2008-01-01

    Reciprocity agreements are contracts between two or more parties whereby students pay reduced tuition rates. The rate of reduction is determined by the parameters set forth in each individual state's agreement but may range from a modest reduction in fees to a waiver of full non-resident tuition. In addition to providing tuition relief,…

  15. Gas turbine engine with supersonic compressor

    SciTech Connect

    Roberts, II, William Byron; Lawlor, Shawn P.

    2015-10-20

    A gas turbine engine having a compressor section using blades on a rotor to deliver a gas at supersonic conditions to a stator. The stator includes one or more of aerodynamic ducts that have converging and diverging portions for deceleration of the gas to subsonic conditions and to deliver a high pressure gas to combustors. The aerodynamic ducts include structures for changing the effective contraction ratio to enable starting even when designed for high pressure ratios, and structures for boundary layer control. In an embodiment, aerodynamic ducts are provided having an aspect ratio of two to one (2:1) or more, when viewed in cross-section orthogonal to flow direction at an entrance to the aerodynamic duct.

  16. Compressor station for Arctic gas pipeline

    SciTech Connect

    Mast, B.T.

    1983-02-08

    By not using conventional refrigeration equipment, this process for cooling natural gas as it leaves the compressor requires less costly machinery, consumes less energy, reduces the frequency of mechanical failure, and takes full advantage of the ambient air in cooling the gas. The apparatus includes a gas-to-gas heat exchanger where the cold incoming gas is first preheated by the warm outgoing gas; this raises the initial temperature of the discharge gas to above the ambient temperature. The discharge gas is then cooled by the incoming gas and by the ambient air in a second heat exchanger. Finally, if further cooling is required, the system includes an expander for additional cooling. The design is particularly suited for use on Arctic pipelines to protect the permafrost from being melted by the warm gas.

  17. Stabilized Liner Compressor: The Return of Linus

    NASA Astrophysics Data System (ADS)

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

    2015-11-01

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

  18. Rub energetics of compressor blade tip seals

    SciTech Connect

    Laverty, W.F.

    1981-03-30

    The rub mechanics of aircraft gas turbine engine compressor abradable blade tip seals was studied at simulated engine conditions. In 12 statistically planned, instrumented rub tests using single titanium blades and fiber-metal rubstrips, the rub velocity, incursion rate, incursion depth, blade thickness, and abradable strength were varied to determine the effects on rub energy, heat split between the blade, rubstrip surface and rub debris, and blade and seal wear. The rub energies were found to be most significantly affected by the incursion rate while rub velocity and blade thickness were of secondary importance. In five additional rub tests using single nickel alloy blades and multiple titanium alloy blades, rub energy and wear effects were found to be similar for titanium and nickel alloy blades while rub energies increased for multiple blades relative to single blade test results.

  19. A viscous-inviscid interactive compressor calculations

    NASA Technical Reports Server (NTRS)

    Johnston, W.; Sockol, P. M.

    1978-01-01

    A viscous-inviscid interactive procedure for subsonic flow is developed and applied to an axial compressor stage. Calculations are carried out on a two-dimensional blade-to-blade region of constant radius assumed to occupy a mid-span location. Hub and tip effects are neglected. The Euler equations are solved by MacCormack's method, a viscous marching procedure is used in the boundary layers and wake, and an iterative interaction scheme is constructed that matches them in a way that incorporates information related to momentum and enthalpy thicknesses as well as the displacement thickness. The calculations are quasi-three-dimensional in the sense that the boundary layer and wake solutions allow for the presence of spanwise (radial) velocities.

  20. Reciprocal Relationships between Attitude toward Mathematics and Achievement in Mathematics.

    ERIC Educational Resources Information Center

    Ma, Xin

    1997-01-01

    This study examined reciprocal relationships between attitude toward mathematics and mathematics achievement. High school seniors from the Dominican Republic completed mathematics achievement tests and a questionnaire on mathematics attitudes. Results indicated that reciprocal relationships existed, suggesting that the reciprocal nature between…