bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Quantitative Visualisation of the Flow in a 1/10th Scale Model Thrust Reverser at the Aircraft Research Association, Bedford
Authors: Bryanston-Cross P. , Sale R. 
Published: March 2015

A series of laser visualisation measurements has been made to both visualise and map the velocity and direction of the transonic flow from a 1/10th scale model of a thrust reverser. The measurements which have been made by injecting micron sized water droplets into the flow, used two techniques to provide a quantitative measurement of the flow field.
The first technique LLS (laser light sheet) provided a general view of the flow, whereas a second pulse laser technique PIV (particle image velocimetry) made a specific measurement in the vicinity of the thrust reverser’s ‘kicker’ plate to map the velocity and direction of the exit flow.
This successful study is, to the best of the author’s knowledge, the first example of a whole field quantitative visualisation being achieved in such a turbulent transonic flow.
Heat Transfer and Aerodynamics of a High Rim Speed Turbine Nozzle Guide Vane With Profiled End Walls
Authors: Chana K. S. 
Published: March 2015

It has been shown that the secondary flows present within turbine nozzle guide vanes have a marked effect on heat transfer. The horse-shoe and passage vortices, for example, have a major impact on platform and vane suction surface heat transfer. To investigate these effects further, heat transfer and aerodynamic measurements have been made on an annular transonic turbine nozzle guide vane ring, with three different platform geometries. The measurements were taken in the Isentropic Light Piston test facility at RAE Pyestock at representative values of engine Reynolds number, Mach number and freestream gas-to-wall temperature ratio.
This paper compares and discusses the measured platform and vane suction surface Nusselt and Mach number distributions for the three different endwall profiles. Comparisons with theoretical flow and heat transfer predictions are presented.
Development of a Direct Coal-Fired Combined Cycle for Commercial Application
Authors: Bannister R. L. , Wiant B. C. , Diehl R. C. , Eppich H. M. , Jensen A. R. , Mach F. V. , Claeson E. U. , Raatikka L. M. , Newby R. A. 
Published: March 2015

A program has been underway since 1986 by Westinghouse Electric Corporation, Textron, Inc., and the sponsoring agency, the Morgantown Energy Technology Center (METC) of the U.S. Department of Energy (DOE), as participants, to establish the technology base for coal-fired combustion turbines targeted for power generation (50 to 150 MW size units). The developed system must be able to burn unbeneficiated, low-cost, utility-grade coal and meet the EPA New Source Performance Standards (NSPS) for coal-fired steam generators (Thoman et al., 1987).
Development of a high pressure (12 to 16 atms) slagging combustor is the key to making a direct coal-fired combustion turbine a commercial reality. In testing to date, a 6 atm slagging combustor, rated at 12 MMBtu/hr (12.7 MHkJ/hr) has demonstrated its ability to handle high- and low-sulfur bituminous coals, and low-sulfur subbituminous coal. The program objectives relative to combustion efficiency, combustor exit temperature and pattern factor, NOx emissions, carbon burnout, and slag rejection have been met.
Today, Northern States Power, working with Westinghouse with assistance from Textron is developing a plan to commercialize a direct coal-fired advanced combined cycle (DCFACC). Included in this plan is a pilot plant (which does not include a combustion turbine) and a demonstration plant that would utilize a 50 MW combustion turbine. The first commercial DCFACC, which would Include a 100 MW combustion turbine, is scheduled to be operational by the year 2001. The cooperative effort among Northern States Power, Westinghouse, and Textron is financially independent of the work now sponsored by DOE/METC.
This paper presents the status of the pressurized slagging combustor development program including recent work to reduce alkali, particulates and SOx levels leaving the combustor and gives an overview of our commercialization process and plan.
Experience With the Commissioning of a Natural Gas Power Recovery Turbine
Authors: Stoll Herbert 
Published: March 2015

For major users of natural gas whose consumption of gas remains constant on annual average, it may be economical to recover pressure energy in a power recovery turbine instead of destroying it by throttling the gas line pressure to the level of the supply system.
Dortmunder Stadtwerke AG, a municipal power and transport utility at the eastern end of the Ruhr engaged RWTUV to provide consultancy and inspection services for the commissioning of such an installation and to conduct performance tests on all machine components.
The special features of the control behaviour of the installation during flow-rate-oriented operation of the turbine are to be dealt with in this paper. This will be done from the point of view of a throttle-loss-free flow, as far as achievable, into the nozzle groups through the turbine inlet valves. The features of control behaviour during startup and in the case of load changes with regard to heat supply using unit cogeneration plant modules will also be looked at.
Furthermore a report will be given on the special features of the performance test.
A PC-Based Inverse Design Method Applied to Radial Inflow Turbines
Authors: Skoe Ivar Helge 
Published: March 2015

The method described herewith is an ‘engineering’ approach to the inverse design problem where both aerodynamic and mechanical criteria are imposed. A novel exducer configuration, with slanted trailing edge, evloves during the iterative design procedure based on the introduction of:
- a realistic loss distribution
- a prescribed rotor exit spanwise total pressure distribution
- and with the imposed geometric restrictions.
For a Gas Generator Turbine, ‘back-to-back’ traverse results show reduced loss for the novel design as compared with a conventionally designed Radial Inflow Turbine.
Through extensive use of ‘Bezier Curves’ for the aerodynamically defined 3-D geometry, the same ‘solid model’ is used to prepare the input files for the structural analysis (’meshing’ for the FEM) as well as the geometry definition for production.
A Viscous Axisymmetric Throughflow Prediction Method for Multi-Stage Compressors
Authors: Ucer Ahmet S. , Shreeve Raymond P. 
Published: March 2015

This paper describes a computer code which solves viscous axisymmetric flow through multistage compressors. The code incorporates the modelling of 3-D effects which result from secondary flow and mixing and lead to property changes in the streamwise and spanwise directions. The method requires no extra data for loss, deviation and blockage. The necessary input data are the geometry, upstream stagnation conditions, rotational speed and mass flow rate. Blade wakes and their decay are modelled. The secondary flow component of the mixing coefficient modifies the uniform part and the result is used in the turbulent diffusion terms of the equation of motion.
The P&W 3S1 low aspect ratio 3 stage compressor and UTRC 2 stage research compressor are used for validation. Considering the complexity of the flow in the multi-stage environment, it was concluded that the method gives encouraging results at a very economical rate.
Brush Seal Leakage Performance With Gaseous Working Fluids at Static and Low Rotor Speed Conditions
Authors: Carlile Julie A. , Hendricks Robert C. , Yoder Dennis A. 
Published: March 2015

The leakage performance of a brush seal with gaseous working fluids at static and low rotor speed conditions was investigated. This report includes the leakage results for air, helium, and carbon dioxide at several bristle/rotor interferences. In addition, the effects of packing a lubricant into the bristles and also of reversing the pressure drop across the seal were investigated. Results were compared to that of an annular seal at similar operating conditions. In order to generalize the results, they were correlated using corresponding state theory. The brush seal tested had a bore diameter of 3.792 cm (1.4930 in.), a fence height of 0.0635 cm (0.025 in.), and 1800 bristles/cm-circumference (4500 bristles/in.-circumference). Various bristle/rotor radial interferences were achieved by using a tapered rotor.
The brush seal reduced the leakage in comparison to the annular seal, up to 9.5 times. Reversing the pressure drop across the brush seal produced leakage rates approximately the same as that of the annular seal. Addition of a lubricant reduced the leakage by 2.5 times when compared to a non-lubricated brush seal. The air and carbon dioxide data were successfully correlated using corresponding state theory. However, the helium data followed a different curve than the air and carbon dioxide data.
Effect of Manufacturing Deviations on Performance of Axial Flow Compressor Blading
Authors: Marson Ezio 
Published: March 2015

Successful compressor aerodynamic performance can be achieved by satisfactory completion of requirements in the following three areas:
aerodynamic design
quality of blading
manufacturing and assembly of the components
Using presently available computer programs capable of doing detailed three dimensional analysis of the flow field, it is possible to obtain excellent aerodynamic designs exceeding 90% isentropic efficiency.
When the design requirements are deviated from the manufacturing process, the result will be less than optimum performance, for example: inadequate surge margin, lowered efficiency, reduced mass flow, etc. may be experienced.
Different types of manufacturing deviations and their effect on compressor performance are analysed in the paper by means of empirical formulas and considerations.
Optimization of an Advanced Combined Cycle and its Application to the Yokohama Thermal Power Station No. 7 and No. 8 Groups
Authors: Aizawa Zengo , Carberg William 
Published: March 2015

Combined cycle technology was successfully applied to the 2000 MW Tokyo Electric Power Co. (TEPCO) Futtsu Station. The fourteen 165 MW single shaft combined cycle Stages were commissioned between 1985 and 1988. Since that time, experience has been accumulated on these 2000 deg F (1100 deg C) class gas turbine based Stages.
With the advent of 2300 deg F (1300 deg C) class gas turbines and dry low NOx technologies, an advanced combined cycle with substantially improved performance became possible. TEPCO commissioned General Electric, Toshiba and Hitachi to perform a study to optimize the use of these technologies. The study was completed and the participants are now doing detailed design of a plant consisting of eight 350 MW single shaft combined cycle Stages. The plant will be designated the Yokohama Thermal Power Station No. 7 and No. 8 Groups.
This paper discusses experience gained at the Futtsu Station, the results of the optimization study for an advanced combined cycle and the progress of the design for Yokohama Groups No. 7 and No. 8.
High Pressure Ratio Intercooled Turboprop Study
Authors: Rodgers C. 
Published: March 2015

High altitude long endurance unmanned aircraft impose unique contraints on candidate engine propulsion systems and types. Piston, rotary and gas turbine engines have been proposed for such special applications. Of prime importance is the requirement for maximum thermal efficiency (minimum specific fuel consumption) with minimum waste heat rejection. Engine weight, although secondary to fuel economy, must be evaluated when comparing various engine candidates. Weight can be minimized by either high degrees of turbocharging with the piston and rotary engines, or by the high power density capabilities of the gas turbine.
The design characteristics and features of a conceptual high pressure ratio intercooled turboprop are discussed. The intended application would be for long endurance aircraft flying at an altitude of 60,000 ft. (18,300 m). It is estimated that such a turboprop would be capable of thermal efficiencies exceeding 40% with current state-of-the-art component efficiency levels and an overall compressor pressure ratio of 66.0. Projected Power (at altitude) to weight ratio is comparable to that of competitive piston and rotary engines.
A Scoping Study for Hypersonic Transport Propulsion Systems
Authors: Kuo Simion C. , Doernbach Jay D. , Champagne George , Tatara A. , Futamura H. , Watanabe Y. , Aoki T. 
Published: March 2015

Hypersonic aircraft and their propulsion systems are exposed to severe aerothermal environments which require a system approach to create innovative designs able to respond to the environmental challenges. This paper describes a preliminary study used to scope the technical challenges and identify the necessary development plans for the aircraft propulsion system. Presented here are the interim results of this scoping study for a turboramjet conceptual design conducted by UTC, Pratt & Whitney. This study is the first of four phases in a 6 year program on Hypersonic Transport Ramjet (HYTRAM) system R&D sponsored by NEDO, as an integral part of the Japanese National Project on “Super/Hypersonic Transport Propulsion Systems (HYPR)”.
Various turboramjet configurations were evaluated and two attractive candidates, a co-axial and a split flow configuration, were selected. Performance analyses were conducted for these two by incorporating the subsystem performance data provided by the Japanese companies (IHI on the turbofan and MHI on the inlet and nozzle). Pre–conceptual mechanical design sketches were prepared to provide some elementary definitions of the co–axial and the split flow turboramjet to assist in selecting a baseline configuration. Candidate materials including composites for the major subsystems were selected, using metals for near–term applications and including ceramics for far–term applications. Using the above results from this scoping study, the co–axial configuration was selected as the baseline because of its higher Figure of Merit estimated from its performance, mechanical design characteristics and the technical challenge it presented.
High Temperature Oxidation and Corrosion of Engineering Ceramics
Authors: Nickel Klaus G. , Fu Zhe , Quirmbach Peter 
Published: March 2015

The problems of high temperature oxidation and corrosion of Si3N4 and SiC are discussed, other ceramics usually do not meet the requirements of structural applications at high temperatures.
If the application has to meet very defined limits of size change it is necessary to specify the exact material composition as well as the atmosphere composition and physical environment to be able to specify the limits. This is in any case true for extremely reducing conditions or very high temperatures.
Under oxidising conditions the region between ≈ 850–1100°C should be avoided when salty, sulfurous and wet fuel conditions are expected.
High temperature limits for long-time applications of Si3N4 in oxidising environments are between 1200–1400°C, corresponding to eutectic temperatures of the glass phase.
The ultimate temperature limit for long-time use of SiC is likely to be between 1700–1800°C, where bubble formation and spallation may become inevitable.
Textron Lycoming AGT1500 Engine: Transitioning for Future Applications
Authors: Horan Richard 
Published: March 2015

The AGT1500 engine was specifically designed as a propulsion unit for U.S. Army main battle tanks. This application required a gas turbine unique in configuration with features, capabilities and attributes different from conventional aircraft gas turbine engines. The engine is a very compact, rugged, modular design with overhead access for maintenance and good part power fuel consumption achieved through a unique compact recuperator. These features, along with a cycle and control system optimized for sea level operation, low smoke and low thermal and noise signature, also provide a low cost gas turbine engine which readily meets requirements for other ground based commercial and military applications. The commercial marine industrial derivative of the AGT1500 is designated the TF15. TF15 applications currently under active consideration and development by Textron Lycoming and potential users include (1) railroad locomotives, (2) stationary continuous duty cogenerative power units, (3) standby emergency and peaking power generators, and (4) natural gas and liquid pumping and (5) marine propulsion and shipboard electrical generation systems.
This paper considers the operational and design characteristics for these applications and shows how the AGT1500/TF15 engine will accommodate these requirements with little or no modifications to the basic automotive engine.
Clinically and Microbiologically Derived Azithromycin Susceptibility Breakpoints for Salmonella enterica Serovars Typhi and Paratyphi A
Authors: Parry Christopher M. , Thieu Nga Tran Vu , Dolecek Christiane , Karkey Abhilasha , Gupta Ruchi , Turner Paul , Dance David , Maude Rapeephan R. , Ha Vinh , Tran Chinh Nguyen , Thi Phuong Le , Be Bay Pham Van , Phi La Tran Thi , Ngoc Rang Nguyen , Ghose Aniruddha , Dongol Sabina , Campbell James I. , Thanh Duy Pham , Thanh Tuyen Ha , Moore Catrin E. , Sona Soeng , Gaind Rajni , Deb Monorama , Anh Ho Van , Van Sach Nguyen , Tinh Hien Tran , Day Nicholas P. J. , Dondorp Arjen , Thwaites Guy , Faiz Mohamed Abul , Phetsouvanh Rattanaphone , Newton Paul , Basnyat Buddha , Farrar Jeremy J. , Baker Stephen 
Published: March 2015

ABSTRACT

Azithromycin is an effective treatment for uncomplicated infections with
Salmonella enterica
serovar Typhi and serovar Paratyphi A (enteric fever), but there are no clinically validated MIC and disk zone size interpretative guidelines. We studied individual patient data from three randomized controlled trials (RCTs) of antimicrobial treatment in enteric fever in Vietnam, with azithromycin used in one treatment arm, to determine the relationship between azithromycin treatment response and the azithromycin MIC of the infecting isolate. We additionally compared the azithromycin MIC and the disk susceptibility zone sizes of 1,640
S
. Typhi and
S
. Paratyphi A clinical isolates collected from seven Asian countries. In the RCTs, 214 patients who were treated with azithromycin at a dose of 10 to 20 mg/ml for 5 to 7 days were analyzed. Treatment was successful in 195 of 214 (91%) patients, with no significant difference in response (cure rate, fever clearance time) with MICs ranging from 4 to 16 μg/ml. The proportion of Asian enteric fever isolates with an MIC of ≤16 μg/ml was 1,452/1,460 (99.5%; 95% confidence interval [CI], 98.9 to 99.7) for
S
. Typhi and 207/240 (86.3%; 95% CI, 81.2 to 90.3) (
P
< 0.001) for
S
. Paratyphi A. A zone size of ≥13 mm to a 5-μg azithromycin disk identified
S
. Typhi isolates with an MIC of ≤16 μg/ml with a sensitivity of 99.7%. An azithromycin MIC of ≤16 μg/ml or disk inhibition zone size of ≥13 mm enabled the detection of susceptible
S
. Typhi isolates that respond to azithromycin treatment. Further work is needed to define the response to treatment in
S
. Typhi isolates with an azithromycin MIC of >16 μg/ml and to determine MIC and disk breakpoints for
S
. Paratyphi A.
The Collagen Binding Protein Cnm Contributes to Oral Colonization and Cariogenicity of Streptococcus mutans OMZ175
Authors: Miller James H. , Avilés-Reyes Alejandro , Scott-Anne Kathy , Gregoire Stacy , Watson Gene E. , Sampson Edith , Progulske-Fox Ann , Koo Hyun , Bowen William H. , Lemos José A. , Abranches Jacqueline 
Published: March 2015

ABSTRACTStreptococcus mutansis the etiological agent of dental caries and one of the many bacterial species implicated in infective endocarditis. The expression of the collagen-binding protein Cnm byS. mutanshas been associated with extraoral infections, but its relevance for dental caries has only been theorized to date. Due to the collagenous composition of dentinal and root tissues, we hypothesized that Cnm may facilitate the colonization of these surfaces, thereby enhancing the pathogenic potential ofS. mutansin advancing carious lesions. As shown for extraoral endothelial cell lines, Cnm mediates the invasion of oral keratinocytes and fibroblasts byS. mutans. In this study, we show that in the Cnm+native strain, OMZ175, Cnm mediates stringent adhesion to dentinal and root tissues as well as collagen-coated surfaces and promotes both cariogenicity and carriagein vivo. In vitro,ex vivo, andin vivoexperiments revealed that while Cnm is not universally required forS. mutanscariogenicity, it contributes to (i) the invasion of the oral epithelium, (ii) enhanced binding on collagenous surfaces, (iii) implantation of oral biofilms, and (IV) the severity of caries due to a native Cnm+isolate. Taken together, our findings reveal that Cnm is a colonization factor that contributes to the pathogenicity of certainS. mutansstrains in their native habitat, the oral cavity.
Identification and Characterization of Mutations Conferring Resistance to d-Amino Acids in Bacillus subtilis
Authors: Leiman Sara A. , Richardson Charles , Foulston Lucy , Elsholz Alexander K. W. , First Eric A. , Losick Richard 
Published: March 2015

ABSTRACTBacteria produced-amino acids for incorporation into the peptidoglycan and certain nonribosomally produced peptides. However,d-amino acids are toxic if mischarged on tRNAs or misincorporated into protein. Common strains of the Gram-positive bacteriumBacillus subtilisare particularly sensitive to the growth-inhibitory effects ofd-tyrosine due to the absence ofd-aminoacyl-tRNA deacylase, an enzyme that prevents misincorporation ofd-tyrosine and otherd-amino acids into nascent proteins. We isolated spontaneous mutants ofB. subtilisthat survive in the presence of a mixture ofd-leucine,d-methionine,d-tryptophan, andd-tyrosine. Whole-genome sequencing revealed that these strains harbored mutations affecting tRNATyrcharging. Three of the most potent mutations enhanced the expression of the gene (tyrS) for tyrosyl-tRNA synthetase. In particular, resistance was conferred by mutations that destabilized the terminator hairpin of thetyrSriboswitch, as well as by a mutation that transformed a tRNAPheinto atyrSriboswitch ligand. The most potent mutation, a substitution near the tyrosine recognition site of tyrosyl-tRNA synthetase, improved enzyme stereoselectivity. We conclude that these mutations promote the proper charging of tRNATyr, thus facilitating the exclusion ofd-tyrosine from protein biosynthesis in cells that lackd-aminoacyl-tRNA deacylase.IMPORTANCEProteins are composed ofl-amino acids. Mischarging of tRNAs withd-amino acids or the misincorporation ofd-amino acids into proteins causes toxicity. This work reports on mutations that confer resistance tod-amino acids and their mechanisms of action.