Experimental program for the evaluation of turbofan/turboshaft c conversion technology

A TF34 turbofan engine is being modified to produce shaft power from an output coupling on the fan disk when variable inlet guide vanes are closed to reduce fan airflow. The engine, called a convertible engine, could be used on advanced rotorcraft such as X-wing, ABC (Advanced Blade Concept), and Folding Tilt Rotor, and on V/STOL craft in which two engines are cross-coupled. The engine will be tested on an outdoor static test stand at NASA Lewis Research Center. Steady-state tests will be made to measure performance in turbofan, turboshaft, and combined power output modes. Transient tests will be made to determine the response to the engine and a new digital engine control system for several types of rapid changes in thrust and shaft loads. The paper describes the engine modifications, the test facility equipment, proposed testing techniques for several types of tests, and typical test results predicted from engine performance computer programs

Characterization and Dynamics of Substituted Ruthenacyclobutanes Relevant to the Olefin Cross-Metathesis Reaction

The reaction of the phosphonium alkylidene [(H_(2)IMes)RuCl2═CHP(Cy)_3)]^(+) BF_(4)^− with propene, 1-butene, and 1-hexene at −45 °C affords various substituted, metathesis-active ruthenacycles. These metallacycles were found to equilibrate over extended reaction times in response to decreases in ethylene concentrations, which favored increased populations of α-monosubstituted and α,α′-disubstituted (both cis and trans) ruthenacycles. On an NMR time scale, rapid chemical exchange was found to preferentially occur between the β-hydrogens of the cis and trans stereoisomers prior to olefin exchange. Exchange on an NMR time scale was also observed between the α- and β-methylene groups of the monosubstituted ruthenacycle (H_(2)IMes)Cl_(2)Ru(CHRCH_(2)CH_(2)) (R = CH_3, CH_(2)CH_3, (CH_2)_)_(3)CH_3). EXSY NMR experiments at −87 °C were used to determine the activation energies for both of these exchange processes. In addition, new methods have been developed for the direct preparation of metathesis-active ruthenacyclobutanes via the protonolysis of dichloro(1,3-bis(2,4,6-trimethylphenyl)-2-imidazolidinylidene)(benzylidene) bis(pyridine)ruthenium(II) and its 3-bromopyridine analogue. Using either trifluoroacetic acid or silica-bound toluenesulfonic acid as the proton source, the ethylene-derived ruthenacyclobutane (H_(2)IMes)Cl_(2)Ru(CH_(2)CH_(2)CH_(2)) was observed in up to 98% yield via NMR at −40 °C. On the basis of these studies, mechanisms accounting for the positional and stereochemical exchange within ruthenacyclobutanes are proposed, as well as the implications of these dynamics toward olefin metathesis catalyst and reaction design are described

Development of a meter for measurement of sewer flow

An experimental and analytical study was performed to develop the geometry for a Venturi type flow meter for use in sewer flow measurement. The meter consists of a constriction in the pipe which produces critical flow under open channel flow conditions and acts as a conventional Venturi meter under full flow conditions. The constriction is constructed using cylindrical segments whose diameter are larger than that of the pipe and which are attached to the sides of the pipe, leaving the invert and crown clear. Head loss characteristics and experimental rating curves for both open channel and full flow conditions are described. A procedure is presented, based on experimental data, to theoretically construct a rating curve if experimental calibration is impractical. Information is also presented to permit the selection of geometrical parameters for optimum performance for a specific installation.U.S. Department of the InteriorU.S. Geological SurveyOpe

Sorption-induced Static Bending of Microcantilevers Coated with Viscoelastic Material

Absorption of a chemical analyte into a polymercoating results in an expansion governed by the concentration and type of analyte that has diffused into the bulk of the coating. When the coating is attached to a microcantilever, this expansion results in bending of the device. Assuming that absorption (i.e., diffusion across the surface barrier into the bulk of the coating) is Fickian, with a rate of absorption that is proportional to the difference between the absorbed concentration and the equilibrium concentration, and the coating is elastic, the bending response of the coated device should exhibit a first-order behavior. However, for polymercoatings, complex behaviors exhibiting an overshoot that slowly decays to the steady-state value have been observed. A theoretical model of absorption-induced static bending of a microcantilever coated with a viscoelastic material is presented, starting from the general stress/strain relationship for a viscoelastic material. The model accounts for viscoelasticstress relaxation and possible coating plasticization. Calculated responses show that the model is capable of reproducing the same transient behavior exhibited in the experimental data. The theory presented can also be used for extracting viscoelasticproperties of the coating from the measured bending data

Low energy proton bidirectional anisotropies and their relation to transient interplanetary magnetic structures: ISEE-3 observations

It is known that the interplanetary medium in the period approaching solar maximum is characterized by an enhancement in the occurrence of transient solar wind streams and shocks and that such systems are often associated with looplike magnetic structures or clouds. There is observational evidence that bidirectional, field aligned flows of low energy particles could be a signature of such looplike structures, although detailed models for the magnetic field configuration and injection mechanisms do not exist at the current time. Preliminary results of a survey of low energy proton bidirectional anisotropies measured on ISEE-3 in the interplanetary medium between August 1978 and May 1982, together with magnetic field data from the same spacecraft are presented

Tester periodically registers dc amplifier characteristics

Motor-driven switcher-recorder periodically registers the zero drift and gain drift signals of a dc amplifier subjected to changes in environment. A time coding method is used since several measurements are shared on a single recorder trace

Isolation and characterisation of 17 microsatellite loci for the red-billed chough (Pyrrhocorax pyrrhocorax)

Peer reviewedPostprin

Safety and efficacy of procedural sedation and analgesia (PSA) conducted by medical officers in a level 1 hospital in Cape Town

Objectives. To study the efficacy and safety of procedural sedation and analgesia (PSA) administered by medical officers (MOs) without formal anaesthetic training.Methods. A retrospective descriptive study in the Emergency Department (ED) of False Bay Hospital (FBH), situated in the southern suburbs of the Cape Town Metro Health District. The study included all patients who  received PSA at FBH between 1 March 2007 and 31 August 2009. Variables recorded included age, gender, physical status as determined by the American Society of Anesthesiologists (ASA status), procedure, fasting and intoxication status, PSA medications, adverse effects, rescue manoeuvresperformed, if any, and time to discharge. Analysis was largely descriptive and clinical and demographic data are presented as means (standard deviations), medians, ranges and proportions as appropriate. Success of sedation and incidence of adverse effects are presented as proportions.Results. Of 166 patients, 140 (84.3%) showed a good level of sedation, 14 (8.4%) were inadequately sedated, 5 (3%) were too deeply sedated but showed no signs of respiratory compromise, and 7 (4.2%) developed respiratory side-effects. Respiratory complications were treated with simple airway manoeuvres; no patient required intubation or experienced respiratory problems after waking up. There was no significant difference in the risk of adverse effects between the fasted and non-fasted groups.  Mildly intoxicated patients who received PSA were at a higher risk of adverse effects.Conclusion. PSA can be administered safely by medical officers. Future research should expand on PSA research in this setting and focus on safety and patient satisfaction.S Afr Med J 2011;101:895-898

Microscopic open channel boundary layer velocity measurement using a virtual image method

A method for velocity measurement is described which employs a microscope and high speed motion picture camera to record the motion of small tracer particles suspended in the flow. The procedure, termed the image method, involves particle illumination such that the particle itself and its virtual image created by reflection from a boundary both appear on the film. The boundary is then located equidistant from the two images. The plane of focus is oriented normal to the boundary giving a picture of the entire velocity profile normal to the boundary within the limits of the field of view. A frame by frame analysis of the particle motion can yield velocity profile and turbulence information. The image method was adapted to a small open channel. Considerable difficulty was encountered in illuminating the particles with sufficient intensity to impress their image on the film. Thus, quantitative data was not obtained. It was concluded that the lens system used to focus the light source was inadequate. However, the method has potential applications in velocity measurement near a boundary and flow visualization ' studies.U.S. Department of the InteriorU.S. Geological SurveyOpe

Microscopic determination of boundary shear and sublayer turbulence characteristics in an open channel

The application of a method of velocity determination in an open channel using a microscope and camera to record the motion of small particles suspended in water is described. Velocity measurements were made in a series of thin planes orientated parallel to the channel bottom for the case of two-dimensional laminar and turbulent open channel flow. Velocity profiles near the boundary were plotted and boundary shear computed from the rate of shear thus determined. Turbulence intensity was computed and the distribution of particle velocities examined. It was concluded that the method yields boundary shear values + to within - 15 percent and that this uncertainty can be reduced significantly. The maximum error is caused by uncertainty in the location of: the focal plane and in the location of a particle within the focal plane. This difficulty causes an even greater error in computation of turbulence intensity. This error increases as the distance from the boundary decreases, creating a serious disadvantage of the method. Particle velocity distributions exhibit a positive third moment which is in qualitative agreement with previous measurements. The results indicate that further investigation of the application of the method to open channel turbulent flow is justified. It is planned to modify the method so that particle motion can be viewed in a plane orientated normal to the boundary. This will considerably reduce the primary errors described in this report and permit more accurate turbulence measurements very near the boundary.U.S. Department of the InteriorU.S. Geological SurveyOpe