bluuebunny/crossref_metadata_2025 huggingface dataset:
Antimicrobials in Animal Agriculture: Parables and Policy
Authors: Scott H. M. , Midgley G. , Loneragan G. H.
Published: April 2015

In addition to the scientific, economic, regulatory and other policy factors that impact on antimicrobial decision‐making in different jurisdictions around the world, there exist ethical, social and cultural bases for the contemporary use of these products in animal agriculture. Thus, the use of the word ‘parable’ to describe the contemporary moral stories that help to guide ethical antimicrobial use practices and broader policy decisions in animal agriculture is appropriate. Several of these stories reflect difficult decisions that arise from conflicting moral imperatives (i.e. both towards animal welfare and towards human health). Understanding the factors that combine to define the past and present paradigms of antimicrobial usage is crucial to mapping a path forward. There exist barriers, as well as opportunities, for advancing scenarios for reducing antimicrobial usage under a variety of voluntary, regulatory and legal policy frameworks. Any new approaches will ideally be structured to extend the use of present‐day antimicrobials into the future, to provide novel alternatives for regulating any newly introduced antimicrobial products so as to maximize their useful life span and to ensure the optimal use of these products in animal agriculture to protect not only the health of animals and the interests of animal health/agriculture stakeholders, but also the human health and the interests of the public at large. A full range of policy approaches, which span the realm from strictly enforced regulations and laws to voluntary guidelines and compliance, should be explored with respect to their risks and benefits in a variety of worldwide settings and in full consideration of a range of stakeholder values.
Regulation of calcium clock‐mediated pacemaking by inositol‐1,4,5‐trisphosphate receptors in mouse sinoatrial nodal cells
Authors: Kapoor Nidhi , Tran Andrew , Kang Jeanney , Zhang Rui , Philipson Kenneth D. , Goldhaber Joshua I.
Published: April 2015

Key points

Inositol‐1,4,5‐trisphosphate receptors (IP3Rs) modulate pacemaking in embryonic heart, but their role in adult sinoatrial node (SAN) pacemaking is uncertain.

We found that stimulation of IP3Rs accelerates spontaneous pacing rate in isolated mouse SAN cells, whereas inhibition of IP3Rs slows pacing.

In atrial‐specific sodium‐calcium exchanger (NCX) knockout (KO) SAN cells, where the Ca2+ clock is uncoupled from the membrane clock, IP3R agonists and antagonists modulate the rate of spontaneous Ca2+ waves, suggesting that IP3R‐mediated Ca2+ release modulates the Ca2+ clock.

IP3R modulation also regulates Ca2+ spark parameters, a reflection of ryanodine receptor open probability, consistent with the effect of IP3 signalling on Ca2+ clock frequency.

Modulation of Ca2+ clock frequency by IP3 signalling in NCX KO SAN cells demonstrates that the effect is independent of NCX.

These findings support development of IP3 signalling modulators for regulation of heart rate, particularly in heart failure where IP3Rs are upregulated.

Cardiac pacemaking initiated by the sinus node is attributable to the interplay of several membrane currents. These include the depolarizing ‘funny current’ (If) and the sodium‐calcium exchanger current (INCX). The latter is activated by ryanodine receptor (RyR)‐mediated calcium (Ca2+) release from the sarcoplasmic reticulum (SR). Another SR Ca2+ release channel, the inositol‐1,4,5‐triphosphate receptor (IP3R), has been implicated in the generation of spontaneous Ca2+ release in atrial and ventricular cardiomyocytes. Whether IP3R‐mediated Ca2+ release also influences SAN automaticity is controversial, in part due to the confounding influence of periodic Ca2+ flux through the sarcolemma accompanying each beat. We took advantage of atrial‐specific sodium–calcium exchanger (NCX) knockout (KO) SAN cells to study the influence of IP3 signalling on cardiac pacemaking in a system where periodic intracellular Ca2+ cycling persists despite the absence of depolarization or Ca2+ flux across the sarcolemma. We recorded confocal line scans of spontaneous Ca2+ release in WT and NCX KO SAN cells in the presence or absence of an IP3R blocker (2‐aminoethoxydiphenyl borate, 2‐APB), or during block of IP3 production by the phospholipase C inhibitor U73122. 2‐APB and U73122 decreased the frequency of spontaneous Ca2+ transients and waves in WT and NCX KO cells, respectively. Alternatively, increased IP3 production induced by phenylephrine increased Ca2+ transient and wave frequency. We conclude that IP3R‐mediated SR Ca2+ flux is crucial for initiating and modulating the RyR‐mediated Ca2+ cycling that regulates SAN pacemaking. Our results in NCX KO SAN cells also demonstrate that RyRs, but not NCX, are required for IP3 to modulate Ca2+ clock frequency.
Magnesium Hydride Slurry: A Better Answer to Hydrogen
Storage
Authors: McClaine Andrew W. , Brown Kenneth , Bowen David D. G.
Published: April 2015

By storing hydrogen in an oil-based slurry with powdered magnesium hydride, inexpensive and safe hydrogen storage can be realized. This paper describes the characteristics and benefits of cycling hydrogen in and out of magnesium hydride slurry. An application of magnesium hydride slurry in a baseload wind power system is discussed. It concludes that a 150 MW baseload wind power system can produce an internal rate of return (IRR) of 10% with an electric price of $0.088/kWh. The costs and performance characteristics of this power plant are described.
Sensitivity of Intersegmental Angles of the Spinal Column to Errors Due to Marker Misplacement
Authors: Rouhani Hossein , Mahallati Sara , Preuss Richard , Masani Kei , Popovic Milos R.
Published: April 2015

The ranges of angular motion measured using multisegmented spinal column models are typically small, meaning that minor experimental errors can potentially affect the reliability of these measures. This study aimed to investigate the sensitivity of the 3D intersegmental angles, measured using a multisegmented spinal column model, to errors due to marker misplacement. Eleven healthy subjects performed trunk bending in five directions. Six cameras recorded the trajectory of 22 markers, representing seven spinal column segments. Misplacement error for each marker was modeled as a Gaussian function with a standard deviation of 6 mm, and constrained to a maximum value of 12 mm in each coordinate across the skin. The sensitivity of 3D intersegmental angles to these marker misplacement errors, added to the measured data, was evaluated. The errors in sagittal plane motions resulting from marker misplacement were small (RMS error less than 3.2 deg and relative error in the angular range less than 15%) during the five trunk bending direction. The errors in the frontal and transverse plane motions, induced by marker misplacement, however, were large (RMS error up to 10.2 deg and relative error in the range up to 58%), especially during trunk bending in anterior, anterior-left, and anterior-right directions, and were often comparable in size to the intersubject variability for those motions. The induced errors in the frontal and transverse plane motions tended to be the greatest at the intersegmental levels in the lower lumbar region. These observations questioned reliability of angle measures in the frontal and transverse planes particularly in the lower lumbar region during trunk bending in anterior direction, and thus did not recommend interpreting these measures for clinical evaluation and decision-making.
Natural Cooling and Startup of Steam Turbines: Validity of the Over-Conductivity Function
Authors: Marinescu Gabriel , Stein Peter , Sell Michael
Published: April 2015

The temperature drop during natural cooling and the way in which the steam turbine restarts have a major impact on the cyclic lifetime of critical parts and on the cyclic life of the whole machine. In order to ensure the fastest startup without reducing the lifetime of the turbine critical parts, the natural cooling must be captured accurately in calculation and the startup procedure optimized. During the cool down and restart, all turbine components interact both thermally and mechanically. For this reason, the thermal analyst has to include, in his numerical model, all turbine significant parts—rotor, casings together with their internal fluid cavities, valves, and pipes. This condition connected with the real phenomenon lead-time—more than 100 hours for natural cooling—makes the analysis time-consuming and not applicable for routine projects. During the past years, a concept called “over-conductivity” was introduced by Marinescu et al. (2013, “Experimental Investigation Into Thermal Behavior of Steam Turbine Components—Temperature Measurements With Optical Probes and Natural Cooling Analysis,” ASME J. Eng. Gas Turbines Power, 136(2), p. 021602) and Marinescu and Ehrsam (2012, “Experimental Investigation on Thermal Behavior of Steam Turbine Components: Part 2—Natural Cooling of Steam Turbines and the Impact on LCF Life,” ASME Paper No. GT2012-68759). According to this concept, the effect of the fluid convectivity and radiation is replaced by a scalar function K(T) called over-conductivity, which has the same heat transfer effect as the real convection and radiation. K(T) is calibrated against the measured temperature on a Alstom KA26-1 steam turbine (Ruffino and Mohr, 2012, “Experimental Investigation on Thermal Behavior of Steam Turbine Components: Part 1—Temperature Measurements With Optical Probes,” ASME Paper No. GT2012-68703). This concept allows a significant reduction of the calculation time, which makes the method applicable for routine transient analyses. The paper below shows the theoretical background of the over-conductivity concept and proves that when applied on other machines than KA26-1, the accuracy of the calculated temperatures remains within 15–18 °C versus measured data. A detailed analysis of the link between the over-conductivity and the energy equation is presented as well.
Initial Work on the Application of Protective Coatings to Marine Gas Turbine Components by High-Rate Sputtering
Authors: McClanahan E. D. , Busch R. , Patten J. W. , Fairbanks J.
Published: April 2015

Gas turbines operated in the marine environment are limited in life and performance by sulfidation or hot-corrosion. Protective coatings deposited by sputtering appear to have the potential of significantly increasing engine life over that obtained with current coatings produced by other techniques. The sputtering process and its application to coating hot section components is the subject of this paper. Two programs are described. In one, metallic overlay coatings of the CoCrAlY type were deposited by dc triode sputtering. Deposition conditions were determined which resulted in adherent, crack-free coatings with a fine grained structure. Platinum diffusion barrier layers were also investigated. Sputtering apparatus suitable for coating turbine blades and vanes was constructed. The other program utilized supported discharge radio frequency sputtering to deposit zirconia coatings, which were intended to serve a thermal barrier function as well as a corrosion resistant one. Graded composition interlayers were investigated as a means of improving the compatibility of the zirconia coating with superalloys.
Analysis of Simulated Axial-Flow Turbomachine Wakes for Estimation of Frequency-Response Requirements for Fast-Response Pressure Probes
Authors: Junkhan G. H.
Published: April 2015

Various types of fast-response pressure probes are currently used in turbomachines. One application of these probes is for the measurement of time varying total pressures downstream of an aixal-flow machine rotor. In this paper, the frequency-response requirements for a probe placed in such a stream are estimated using a simulated wake pressure-time function. The analysis indicates that the minimum required response depends mainly on the maximum pressure difference from wake to free stream, the blade passing frequency and the blade row geometry. One of the assumptions made in the analysis is that a fast-response probe with a short total head tube in front of the transducer behaves approximately as a second-order dynamic system. Experimental results are given to illustrate probe behavior both in frequency-response tests and behind an axial-flow rotor. Improved probe frequency response using electronic filters is also illustrated.
Passenger Car Performance With the Experimental Gas Turbine VW—GT 70
Authors: Walzer P. , Buchheim R. , Rottenkolber P. , Hagemann G.
Published: April 2015

This paper describes the performance obtained by the Volkswagenwerk AG with an experimental gas turbine power plant in a passenger car. Following a brief description of the power unit and its installation in the vehicle, results of operational tests are given. The investigations cover both the road performance and the effect on the environment of this experimental turbine car. The results are compared with those from spark ignition engines of similar power. Possible solutions are indicated where the results are considered to be not yet satisfactory.
Experimental Investigations of a Recently Developed Supersonic Compressor Stage (Rotor and Stage Performance)
Authors: Simon H. , Bohn D.
Published: April 2015

The experimental investigations of a recently developed supersonic compressor stage working with a strong shock wave both in the rotor and stator are described. The shock in the inlet area of the rotor is stabilized by the geometry of the rotor blade channel, whereas the position of shocks in the stator is controlled by the back pressure. Due to this, the static pressure rise is distributed to the rotor and stator avoiding a higher loading of the stator. In the first part the performance of the rotor alone has been investigated. The conducted probe and static wall pressure measurements allowed a detailed analysis of the flow through the rotor. The determined performance characteristics of the rotor show the peculiarities of the rotor at different speeds and throttle positions. In addition to the static wall pressure measurements the nonsteady pressure distributions have been measured at the casing wall by piezoelectric pressure transducers. Since this rotor (type ②) has been designed with the same relative inlet Mach number and turning as the previously investigated supersonic rotor (type ①), a direct comparison of these rotors can be made. In the second part of these investigations the rotor of type ② has been combined with a tandem cascade as a stator, to investigate the supersonic compressor stage. With heavy throttling a static pressure ratio of 3,5 (p3/p1) has been achieved. The evaluation of the probe measurements allowed a better estimation of the overall performance of this supersonic compressor stage.
A Parametric Method of Turbine Blade Profile Design
Authors: Dunham J.
Published: April 2015

The profile shape of an axial turbine blade is required to satisfy both aerodynamic and mechanical criteria; the designer wants the most favorable velocity distribution achievable with the permissible blade thickness. The design involves some trial-and-error, especially if the profile is initially prescribed by solely aerodynamic or solely mechanical requirements. A new design technique is described in which both aerodynamic and mechanical requirements are prescribed. The shape is defined by an algebraic function of eight parameters: blade inlet and outlet angle, maximum thickness, trailing edge thickness and wedge angle, leading edge radius, and the points of maximum thickness and maximum camber. Some of these are chosen to satisfy mechanical requirements, and curves are given recommending the best values of the remaining parameters from aerodynamic considerations, with the exception of the position of maximum camber. By varying that over a narrow range, a good shape can quickly be selected. A computer program for designing blades this way and analyzing blades designed in other ways is described.
Operation and Control of the 50-Mw Closed-Cycle Helium Turbine Oberhausen
Authors: Bammert K. , Krey G. , Krapp R.
Published: April 2015

The Oberhausen helium turbine plant will have a multi-compartment storage system for varying the pressure level and two separate bypasses, one for speed control during isolated operation and the other for emergency shutdown. A newly developed safety system with a multiple-protection effect is provided. The report contains the results of the extensive calculation work relating to the operating behavior of the plant, as well as important layout criteria resulting therefrom.
Low-Cost Small Gas Turbine
Authors: Heitmann A. M. , Rizika J. W.
Published: April 2015

This paper presents information on the NREC core engine development program. The subject engine is a 100-hp, two-shaft gas turbine that is the low-power end of a family of engines up to 500 hp, both nonregenerative and regenerative. The major goal of the program has been the development of a low-cost small gas turbine engine (less than $5/hp to produce in quantities of 15,000/yr). Other objectives include low emissions (meeting the anticipated EPA standards for the markets of interest), relatively high performance (design point SFC = 0.7 for the simple-cycle engine and 0.4 for the regenerative version), and relatively long life (10,000-hr life at design power and a minimum service period of 500 hr). Items specifically covered in this paper include the following: (a) A description of the core engine concept. Frame size, regenerative, recuperative, and air compressor versions are discussed. (b) A technical description of the core engine concept. The salient low-cost features are identified. (c) The development program results. Some of the engine performance and manufacturing cost analysis results are given.
Investigation Concerning the Blade Loading of Centrifugal Impellers
Authors: Mizuki Shinpei , Ariga Ichiro , Watanabe Ichiro
Published: April 2015

An investigation concerning the optimum blade loading of centrifugal impellers was performed. The three impellers with straight radial blades employed in the present study were of the same configurations except the shroud profiles which rendered to bring different diffusion ratios from each other. The static pressure distributions on blade surfaces, flow patterns within the impeller channel as well as at impeller inlet and at outlet were measured for these impellers. The effect of a secondary flow within impeller channel was clarified to some extent from the measurements. Theoretical investigation was also performed in order to compare with the experimental data.
High Temperature Turbine Researches at National Aerospace Laboratory in Japan
Authors: Takahara K. , Sasaki M. , Minoda M. , Yamamoto A. , Nouse H. , Sakata K. , Yoshida T.
Published: April 2015

This paper reviews the basic researches of high temperature turbines. These researches include: the performance estimation of a turbo-fan engine with an air-cooled turbine; the relation between the spanwise distribution of cooling effectiveness and the life of the air-cooled turbine blade; experiments of film cooling on the leading edge and on the reduction of unsteady thermal stress in the air-cooled turbine blade; and a new construction of the air-cooled turbine blade. Also discussed are the two-dimensional cascade tests of air-cooled turbine blades by the low-speed and high-speed wind tunnels. Full-scale tests for the high temperature turbine including aerodynamic and thermodynamic investigations of air-cooled axial flow turbines are shown.
Nitric Oxide Formation in the Combustion of Fuels Containing Nitrogen in a Gas Turbine Combustor
Authors: Dilmore J. A. , Rohrer W.
Published: April 2015

Fuels containing chemically bound nitrogen were burned in a 6-in-dia gas turbine combustor and the NOx production was correlated to the nitrogen content of the fuel over a range of air equivalence ratios. The bound nitrogen content varied from 0.0079 percent (79 ppm) to 0.79 percent by weight. Inlet air temperatures of 200 and 600 F were used and outlet temperatures were varied from 1100 to 1800 F. Exhaust gases were continuously monitored and the CO, CO2, NO, and hydrocarbons were measured. The NO, normalized NO, CO, hydrocarbon concentrations and per cent conversion versus combustor outlet temperature are presented. Also, results from a diesel oil containing 0.13 percent artificially added nitrogen were compared to those from a crude oil having 0.13 percent naturally occurring nitrogen.
Design, Development and Applications of Jet Engine Based 800-kW Gas Turbine
Authors: Sinai J. , Rozewicz J.
Published: April 2015

This paper describes the design and test work of a development program of a 800-kW industrial gas turbine utilizing a jet engine gas generator. Design and subsequent manufacture of the power turbine assembly was predicated upon the use of aircraft engine components and technology. The gas turbine was initially intended as standby electric power source. It is planned to utilize the unit in continuous duty service. Solution of aerodynamic and mechanical design problems, and adaptation of control system are outlined. The results of prototype tests are also reported. Performance data correlated well with expected values. Several units have been installed up to date for standby utility service in industrial complexes, airport terminals and on ships. Operational experience with these engines is reviewed.
Application of a Two-Dimensional Supersonic Passage Analysis to the Design of Compressor Rotors
Authors: Hantman R. G. , Mikolajczak A. A. , Camarata F. J.
Published: April 2015

A description of a two-dimensional supersonic cascade passage analysis and its application to the design of a high hub-to-tip ratio supersonic compressor rotor is presented. The analysis, applicable to the case in which the inviscid flow is everywhere supersonic, includes an entrance region calculation which accounts for blade leading edge bluntness effects, and a passage and wake region calculation. The inviscid part of the analysis is solved using a rotational method of characteristics. The effect of the blade boundary layer displacement thickness is taken into consideration. Comparison of the results of the analysis with supersonic cascade data is made, showing good agreement in overall performance prediction, in blade surface static pressure distributions, and in achievement of the desired shock wave patterns. A comparison of the results of the analysis is made also with the performance of a blade section of a high hub-to-tip ratio supersonic compressor and acceptable agreement obtained.
A Unified Approach to the One-Dimensional Analysis and Design of Radial and Mixed Flow Turbines
Authors: Wallace F. J. , Baines N. C. , Whitfield A.
Published: April 2015

A unified one-dimensional analysis and design procedure for radial and mixed flow turbines is presented. This procedure considers the flow in all of the turbine components, including the inlet volute, nozzled or nozzleless inlet duct, rotor and exit duct. Losses are included for each component; in the stationary ducts, friction is the main loss mechanism, and in the rotor skin friction, clearance and disk friction are considered separately. Incidence losses at entry to both nozzle and rotor are calculated using one of two loss models. For each component, the procedure is to combine the equations of continuity, momentum, energy, and entropy into a single dimensionless expression for the Mach number at exit. This approach has proved possible under a wide variety of circumstances, and with its flexibility and ease of programming for solution by computer would seem to have many applications in one-dimensional ducted flow. The predicted performance of a radial inflow nozzleless turbine is compared with experimental results. The comparison is considered to be sufficiently good to confirm the validity of this approach. The results obtained with each of the two incidence loss models are compared. Each model is found to have its own advantages and fields of application.
Design of Optimum Acoustic Treatment for Rectangular Ducts With Flow
Authors: Motsinger R. E. , Kraft R. E. , Zwick J. W.
Published: April 2015

A design optimization technique for acoustic treatment in rectangular ducts with uniform mean flow is presented. The technique is based on the acoustic wave solution in terms of series of characteristic duct modes. The analysis allows multiple axial treatment sections along the length of the duct and requires a known modal characterization of the sound source. Conditions of acoustic pressure and acoustic velocity continuity are used to match modal solutions at planes of impedance discontinuity in the duct. Experimental techniques for obtaining this modal characterization are presented. Using duct modes measured at the source plane, the optimization technique is exercised to design an optimized single element liner in a case without mean flow, and optimized single and dual element liners in cases with mean flow. The validity of the program for predicting noise suppression is demonstrated by comparing analytical predictions with measured data for several (non-optimum) cases. Application to treatment design in turbomachinery exhaust ducts is considered.
A Correlation of Nitrogen Oxides Emissions With Gas Turbine Operating Parameters
Authors: Touchton G. L. , Dibelius N. R.
Published: April 2015

A semi-empirical correlation between nitrogen oxides emissions and combustor humidity, fuel to air ratio, pressure, and temperature is presented. The functional form of the pressure and humidity dependence is taken from the literature. The functional form of the fuel to air ratio and temperature dependence is deduced from consideration of a well-stirred constant residence time reactor model. The correlation is verified for tests of regenerative and simple-cycle constant speed gas turbines and for sea level tests of three different aircraft gas turbine engines. The residual error is approximately ± 10 percent of the measured emission values over the respective operating ranges. The correlation may be used to correct measured NOx emission levels to standard conditions and to predict emission levels from future designs.
Visible Plume Investigation on a Combined Cycle Power Plant
Authors: Carl D. E. , Obidinski E. S. , Stumbar J. P.
Published: April 2015

The visible plume at PSCO PACE 260 is attributable to NO2 in concentrations above 20 ppmv. The NO2 results from the oxidation of NO by the duct burner with no change in total NOX. The exhaust was well within all applicable emission regulations. The plume can be controlled by reducing NO formation in the gas turbine by either wet or dry methods. Future plants are expected to have a less noticeable plume if any at all.
Composite Inlays Increase Flutter Resistance of Turbine Engine Fan Blades
Authors: Troha W. , Swain K.
Published: April 2015

A method for improving turbine engine blade flutter stability was recently demonstrated on a TF41 fan rig and engine. The concept uses the high strength and stiffness properties of B/SiC-titanium composite, bonded into the leading edge tip section of a titanium fan blade, to control the blade vibrational characteristics. Comparisons are made between the blade response characteristics with and without the composite inlay for blade natural frequency, untwist due to rotational speed, and shift in flutter boundary. Engine performance improvements due to shroud removal are also shown.
An Investigation Into the Dynamic Performance of a Variable Pitch Turbofan Using a Hybrid Computer
Authors: MacIsaac B. D. , Saravanamuttoo H. I. H.
Published: April 2015

This paper discusses the results of a study of the dynamic performance of a hypothetical variable pitch turbofan; the study was conducted via a hybrid computer simulation of the engine dynamics. It was found that, by change of fan pitch, the steady-state thrust could be held constant over a wide range of fan speeds. The variable pitch fan could contribute only marginally to improving transient response, by utilizing the stored “flywheel” energy which can be extracted by increasing pitch during the transient. This is made possible by maintaining high fan speeds at low thrust by an appropriate selection of initial pitch. Such operation may cause significant excursions in fan speed, and control by pitch variation may require some increase in the complexity of the engine control system.
Vaporization of LNG With Closed-Cycle Gas Turbines
Authors: Griepentrog H. , Sackarendt P.
Published: April 2015

This paper is a preliminary optimization study showing that fossil-fired closed-cycle gas turbines — an existing technology — can be applied to the vaporization of LNG yielding efficiency values of 58 percent and overall plant efficiencies of more than 80 percent. Here not only the high temperature potential of gas turbines is used, but also the low temperature potential.
Definition and Application of Means for Predicting Shear Turbulent Flows in Turbomachines
Authors: Quémard C. , Michel R.
Published: April 2015

Two calculation methods for predicting shear flows in turbomachines are presented. First, some extension of the classical mixing-length model of turbulence are used to solve particular boundary-layer problems (transpiration cooling, effect of wall curvature, three-dimensional boundary layers). Secondly, in view of a more general study of shear mixing flows, a two-equation model of turbulence, one expressing the development of the turbulent kinetic energy, the other its dissipation, is described and applied in various kinds of flows: wakes, wall jets, boundary layers with a high free-stream turbulence. Comparisons with experiments confirm the validity of both methods and especially the wide range of application of the two-equation model in turbomachine problems.
Effect of Maintenance on Gas Turbine Reliability
Authors: Nichols W. H. , Witt R. H.
Published: April 2015

The importance of reliability is discussed with its relationship to a gas turbine power generation site and the impact of maintenance on reliability, spare parts, site personnel, and equipment. A case history is presented to show how maintenance has improved the reliability of the site. It relates the experiences learned from start-up to today. Areas of major concern are the site personnel concept of maintenance and how it has changed, how maintenance programs have expanded, and the effect of these changes on reliability.
Inflight Engine Performance Evaluations
Authors: Beck W. E.
Published: April 2015

The measurement/determination of installed inflight engine performance on an aircraft is a complex task. To be successful requires that wind tunnel model and full-scale inflight test programs be fully planned early in the development phase of the aircraft design. In particular, methodology and instrumentation requirements must be coordinated in these programs. This paper discusses the requirements and methodology for inflight engine performance evaluations as applied to a subsonic ASW type aircraft. Data are presented which show that two independent methods of calculating steady-state engine net thrust levels agree to within ± 1.5 percent of each other over the full operating regime of the aircraft. Finally, comparisons of calculated performance with that predicted from the engine manufacturer’s cycle deck are presented.
A Multi-Variable Control for a Turbofan Engine Operating at Sea Level Static
Authors: Weinberg M. S.
Published: April 2015

Based on modern control theory, a multi-variable control is formulated for a two-spool turbofan engine operating at sea level static conditions. The proposed control yields idle to intermediate transients in 40 percent of the time required by the conventional controls in non-linear simulations while maintaining similar stall and temperature overshoot characteristics. The formulated control is simpler than earlier proposed multi-variable controls and yields acceptable performance during small thrust changes and decelerations.
Advanced Composite Fan Blade Flight Evaluation Program
Authors: Chopin M. H.
Published: April 2015

The preparation for and conduct of the first flight by the U. S. Air Force of a turbine engine fan stage fabricated of advanced composite materials is discussed. Composite material properties and basic design philosophy is presented along with preliminary flight evaluation results. This is the first application of filamentary-reinforced metal matrix composites to a turbine engine structural component.
Air Inlet Filtration for Gas Turbine Units
Authors: Goldbrunner P. R. , Savoie L.
Published: April 2015

Gas Turbine operators are constantly seeking ways and methods to reduce maintenance cost and extend availability of their units. One method, the use of air inlet filtration, is discussed in this paper. A test of inlet filtration was conducted to solve a unique ingestion problem, but other benefits were also discovered.
High Performance Epicyclic Gears for Gas Turbines
Authors: Imwalle D. E.
Published: April 2015

The history and explanation of the Cinti-BHS load equalization system for epicyclic gears is discussed in detail. Equations for relating gearbox size and weight are presented for parallel shaft and epicyclic gears. A derivation for the maximum ratio for the number of planets is also included.
In situ soft x-ray fluorescence and absorption microspectroscopy: A study of Mn-Co/polypyrrole electrodeposition
Authors: Bozzini Benedetto , Bocchetta Patrizia , Gianoncelli Alessandra , Kourousias George , Kiskinova Maya , Zilio Simone Dal
Published: April 2015

This paper reports the development and application of a novel thin-layer electrochemical microcell for in situ soft x-ray fluorescence and absorption microspectroscopy. The microcell, fabricated using ultraviolet lithography, is an improved version of concepts previously developed in our group, featuring a wide optical window that allows the extension of the range of accessible in situ microspectroscopy and imaging methods, including those requiring small emission take-off angles. The three-electrode design implemented in the cell enables optimal electrochemical control. The first in situ experiment employing this new cell explores the electrochemical growth of a novel Mn-Co/polypyrrole composite that is a prospective electrocatalyst for Pt replacement in air cathodes. Morphological, compositional, and chemical-state distributions of Mn and Co codeposited with polypyrrole are subsequently performed in situ as a function of time and position, yielding otherwise unachievable information regarding the electrodeposition process.
Transient measurements of carrier relaxation time and density in the P3HT:PCBM organic photovoltaic cell
Authors: Kouhestani Camron , Nguyen Duc D. , Kambour Kenneth E. , Devine Roderick A. B. , Chen Johnny , Li Gang , Yang Yang
Published: April 2015

The authors have used transient photovoltage measurements to evaluate carrier relaxation times (τ) in P3HT:PCBM based photocells over a wide range of open circuit voltages. Satisfactory agreement is found with data obtained by low frequency impedance measurements. The authors find the differential capacitance measurements yield data consistent with the theoretical value expected based on Langevin recombination. The Langevin coefficient is three orders of magnitude smaller than the theoretical one. For the low light levels, the relaxation time variation is determined by the RC time constant behavior of the photodiode.
An Interdisciplinary Approach to Drag Forces: Estimating Floodwater Speed from Displaced Riverbed Boulders
Authors: Pestka Kenneth A. , Heindel Jennifer
Published: April 2015

This activity is designed to illustrate an application of resistive forces in the introductory physics curriculum with an interdisciplinary twist. Students are asked to examine images of riverbed boulders after a flood and estimate the water flow that was needed to push the boulders downstream. The activity provides an opportunity for students to gain an understanding of the physics of natural phenomena with applications to environmental science and environmental engineering, to gain a stronger appreciation for physical modeling and estimation, and to become environmental detectives!
Job title of recent bachelor's degree recipients
Authors: White Susan C.
Published: April 2015

Physics bachelor's degree recipients work in all kinds of professions—science writing, medicine, law, history of science, acting, music, healthcare and more. Since very few of these employees have the word “physics” in their job titles, it can be hard for new graduates to know where to look for jobs and how to find other recent physics graduates in the workforce. The American Institute of Physics and the Society of Physics Students joined forces on an NSF-funded grant to create career tools for undergraduate physics students.1 One of the tools available to students in the Careers Toolbox is a listing of common job titles of physics bachelors degree recipients working in various fields; some of the job titles are listed below.
An Arduino Investigation of the RC Circuit
Authors: Galeriu Calin , Letson Cheryl , Esper Geoffrey
Published: April 2015

The experimental investigation of the charging or discharging of a capacitor through a resistor is of fundamental importance to the study of electricity. Students taking the Physics SAT or the AP Physics C: Electricity and Magnetism test have to prove their knowledge of time-varying behavior in RC circuits. While the classical experiment is done using a voltmeter and a stopwatch, this procedure is tedious and prone to human errors. We have developed an alternative procedure in which the voltage, the current, and the time are all measured electronically with the help of an Arduino Uno microcontroller board.
A Modern Bréguet-Type Galvanometer
Authors: Daffron John A. , Greenslade Thomas B.
Published: April 2015

Recently the handsome little galvanometer (only 10 cm high) in Fig. 1 came into the Greenslade Collection. This is a design without a moving coil and, consequently, is very rugged. At the same time, John Daffron independently sent Tom Greenslade the picture of a similar galvanometer that he had made some years back and has been using for experimental work since then. These galvanometers are easy to build and can still be used in the lecture hall.
Cracking knuckles — A smartphone inquiry on bioacoustics
Authors: Müller Andreas , Vogt Patrik , Kuhn Jochen , Müller Marcus
Published: April 2015

Cracking (or popping) knuckles (or joints) is an (bio-) acoustic phenomenon of which most of you are aware (with dislike, in some cases), and some of you may have wondered where it comes from. We will first give a short explanation, followed by a smartphone experiment validating a central phenomenon of the sound generation mechanism.
Don’t Miss, Don’t Miss, D’oh! Performance When Anxious Suffers Specifically Where Least Desired
Authors: Woodman Tim , Barlow Matthew , Gorgulu Recep
Published: April 2015

We present two novel tests of Wegner’s (1994) theory of ironic processes of mental control using a hockey penalty-shooting task (Study 1) and a dart throwing task (Study 2). In Study 1 we aimed to address a significant limitation of ironic effects research in a performance setting by differentiating nonironic performance error from specifically ironic performance error. When instructed not to miss in a specific direction, anxious performers did so a significantly greater number of times; importantly, there was no difference in nonironic error, which provides the first specific support for Wegner’s theory in a performance setting. In Study 2, we present the first examination of the precision of ironic errors. When anxious, participants performed not only more ironically but also performed more precisely in the to-be-avoided zone than when they were not anxious. We discuss the results in the context of the importance of specific instructions in coaching environments.
Ultimately It Comes Down to the Relationship: Experienced Consultants’ Views of Effective Sport Psychology Consulting
Authors: Sharp Lee-Ann , Hodge Ken , Danish Steve
Published: April 2015

The purpose of this investigation was to; (a) examine what experienced SPCs perceived to be the necessary components of the sport psychology consulting relationship, and (b) examine individual contributions of the SPC and client to the consulting relationship. Purposeful sampling was used to recruit 10 experienced SPCs (8 male and 2 female, M age = 50.44 years, M years consulting experience = 21.67 years) who held current sport psychology accreditation/certification and who had considerable consulting experience. Following individual interviews, extensive content analysis revealed that the sport psychology consulting relationship was reflective of (a) rapport, (b) respect, (c) trust, (d) a partnership, and (e) a positive impact on the client. Members of the consulting relationship made individual contributions to the relationship; SPCs contributed; (a) honesty, (b) commitment, (c) knowledge and expertise, (d) counseling skills, and (e) professional ethical behavior. With clients contributing; (a) openness to change, (b) honesty, and (c) willingness to work.
Calcium-sensing receptor antagonists abrogate airway hyperresponsiveness and inflammation in allergic asthma
Authors: Yarova Polina L. , Stewart Alecia L. , Sathish Venkatachalem , Britt Rodney D. , Thompson Michael A. , P. Lowe Alexander P. , Freeman Michelle , Aravamudan Bharathi , Kita Hirohito , Brennan Sarah C. , Schepelmann Martin , Davies Thomas , Yung Sun , Cholisoh Zakky , Kidd Emma J. , Ford William R. , Broadley Kenneth J. , Rietdorf Katja , Chang Wenhan , Bin Khayat Mohd E. , Ward Donald T. , Corrigan Christopher J. , T. Ward Jeremy P. , Kemp Paul J. , Pabelick Christina M. , Prakash Y. S. , Riccardi Daniela
Published: April 2015

Calcilytics reduce airway hyperresponsiveness and inflammation and may represent effective asthma therapeutics.
Seek and destroy—and discover
Authors: Nalepa Grzegorz
Published: April 2015

Functional analysis of a patient-derived mutation unveils a new mode of regulation for the Fanconi-anemia signaling network.
Transcriptomic Analysis of Vulvovaginal Candidiasis Identifies a Role for the NLRP3 Inflammasome
Authors: Bruno Vincent M. , Shetty Amol C. , Yano Junko , Fidel Paul L. , Noverr Mairi C. , Peters Brian M.
Published: April 2015

Treatment of vulvovaginal candidiasis (VVC), caused most frequently by
Candida albicans
, represents a significant unmet clinical need.
C. albicans
, as both a commensal and a pathogenic organism, has a complex and poorly understood interaction with the vaginal environment. Understanding the complex nature of this relationship is necessary for the development of desperately needed therapies to treat symptomatic infection. Using transcriptome sequencing (RNA-seq), we characterized the early murine vaginal and fungal transcriptomes of the organism during VVC. Network analysis of host genes that were differentially expressed between infected and naive mice predicted the activation or repression of several signaling pathways that have not been previously associated with VVC, including NLRP3 inflammasome activation. Intravaginal challenge of Nlrp3
−/−
mice with
C. albicans
demonstrated severely reduced levels of polymorphonuclear leukocytes (PMNs), alarmins, and inflammatory cytokines, including interleukin-1β (IL-1β) (the hallmarks of VVC immunopathogenesis) in vaginal lavage fluid. Intravaginal administration of wild-type (WT) mice with glyburide, a potent inhibitor of the NLRP3 inflammasome, reduced PMN infiltration and IL-1β to levels comparable to those observed in Nlrp3
−/−
mice. Furthermore, RNA-seq analysis of
C. albicans
genes indicated robust expression of hypha-associated secreted aspartyl proteinases 4, 5, and 6 (SAP4–6), which are known inflammasome activators. Despite colonization similar to that of the WT strain, Δ
SAP4–6
triple and Δ
SAP5
single mutants induced significantly less PMN influx and IL-1β during intravaginal challenge. Our findings demonstrate a novel role for the inflammasome in the immunopathogenesis of VVC and implicate the hypha-associated SAPs as major
C. albicans
virulence determinants during vulvovaginal candidiasis.

IMPORTANCE
Vaginitis, most commonly caused by the fungus
Candida albicans
, results in significant quality-of-life issues for all women of reproductive age. Recent efforts have suggested that vaginitis results from an immunopathological response governed by host innate immunity, although an explanatory mechanism has remained undefined. Using comprehensive genomic, immunological, and pharmacological approaches, we have elucidated the NLRP3 inflammasome as a crucial molecular mechanism contributing to host immunopathology. We have also demonstrated that
C. albicans
hypha-associated secreted aspartyl proteinases (SAP4–6 and SAP5, more specifically) contribute to disease immunopathology. Ultimately, this study enhances our understanding of the complex interplay between host and fungus at the vaginal mucosa and provides proof-of-principle evidence for therapeutic targeting of inflammasomes for symptomatic vulvovaginal candidiasis.
Methicillin-Resistant Staphylococcus aureus Adaptation to Human Keratinocytes
Authors: Soong Grace , Paulino Franklin , Wachtel Sarah , Parker Dane , Wickersham Matthew , Zhang Dongni , Brown Armand , Lauren Christine , Dowd Margaret , West Emily , Horst Basil , Planet Paul , Prince Alice
Published: April 2015

Skin is the most common site of
Staphylococcus aureus
infection. While most of these infections are self-limited, recurrent infections are common. Keratinocytes and recruited immune cells participate in skin defense against infection. We postulated that
S. aureus
is able to adapt to the milieu within human keratinocytes to avoid keratinocyte-mediated clearance. From a collection of
S. aureus
isolated from chronically infected patients with atopic dermatitis, we noted 22% had an
agr
mutant-like phenotype. Using several models of human skin infection, we demonstrate that toxin-deficient,
agr
mutants of methicillin-resistant
S. aureus
(MRSA) USA300 are able to persist within keratinocytes by stimulating autophagy and evading caspase-1 and inflammasome activation. MRSA infection induced keratinocyte autophagy, as evidenced by galectin-8 and LC3 accumulation. Autophagy promoted the degradation of inflammasome components and facilitated staphylococcal survival. The recovery of more than 58%
agr
or RNAIII mutants (
P
< 0.0001) of an inoculum of wild-type (WT) MRSA from within wortmannin-treated keratinocytes compared to control keratinocytes reflected the survival advantage for mutants no longer expressing
agr
-dependent toxins. Our results illustrate the dynamic interplay between
S. aureus
and keratinocytes that can result in the selection of mutants that have adapted specifically to evade keratinocyte-mediated clearance mechanisms.

IMPORTANCE
Human skin is a major site of staphylococcal infection, and keratinocytes actively participate in eradication of these pathogens. We demonstrate that methicillin-resistant
Staphylococcus aureus
(MRSA) is ingested by keratinocytes and activates caspase-1-mediated clearance through pyroptosis. Toxin-deficient MRSA mutants are selected within keratinocytes that fail to induce caspase-1 activity and keratinocyte-mediated clearance. These intracellular staphylococci induce autophagy that enhances their intracellular survival by diminishing inflammasome components. These findings suggest that
S. aureus
mutants, by exploiting autophagy, can persist within human keratinocytes.