bluuebunny/crossref_metadata_2025_split huggingface dataset:
Infra-Red Signature Suppression for Marine Gas Turbines: Comparison of Sea Trial and Model Test Results for the DRES Ball IRSS System
Authors: Birk A. M. , Vandam D. 
Published: March 2015

Sea Trials have recently been underway for Canada’s new City Class Patrol Frigate (CPF). These trials provided the first opportunity to measure the performance of the new DRES Ball Infra-red Signature Suppression (IRSS) system installed on a ship. Prior to these trials 1/4 scale hot flow model test and computer simulation performance results were available.
The CPF DRES Ball IRSS systems are installed on the exhaust uptakes of the GE LM2500 main gas turbines. The DRES Ball provides both metal surface cooling for all view angles and plume cooling. The DRES Ball significantly reduces the IR signature of the LM2500 exhaust.
This paper presents a comparison between the 1/4 scale hot flow model test results with the full scale sea trial results. Performance variables included in the comparison are; metal surface temperatures, back pressure, plume temperature distribution, and surface static pressures. Because of the confidential nature of the DRES Ball system performance, all classified data has been nondimensionalized so that only relative comparisons can be made between the full scale and 1/4 scale data.
The results show that the full scale system performs better than the 1/4 scale model because of Reynolds number effects. The plume temperature, surface temperatures and back pressure were all lower (better) than in the 1/4 scale model tests. One of the original concerns with the installation was that relative wind would degrade the performance of the DRES Ball onboard a ship. The wind effect was found to be benign during the trials.
The Redesign of a Marine Gas Turbine Generator Set
Authors: Cheney P. , Abdelrazik A. 
Published: March 2015

After suffering a poor record of reliability and performance deterioration, the gas turbine generator sets of the Canadian Navy Tribal Class destroyers were subjected to an extensive investigation and subsequent redesign. Major components were not found to be at fault but many deficiencies in the supporting equipment were found to be responsible for the high cost in labour and material for maintenance. Full scale model tests aided the redesign and early results of the first installation are very encouraging.
This paper describes many aspects of the redesign and provides some pointers for the successful design of a marine gas turbine installation.
The U.S. Navy’s Design, Development and Implementation Program for Gas Turbine Generator Sets
Authors: McGroarty John J. 
Published: March 2015

The Design Development and Implementation Program (DDIP) evolved as a result of an organized progression of In-Service Engineering (ISE) responsibilities required to implement improvements to Gas Turbine Generator Sets (GTGS) in the U.S. Navy. The DDIP was established to bring a design concept, whether it be to correct a problem or to make a design improvement, from the drawing board through testing and development to the implementation of a Technical Directive as quickly as possible. Presently all engineering improvements on U.S. Navy Gas Turbine Generator Sets are implemented through the DDIP. Providing this central point of engineering has helped the Naval Sea Systems Command implement improvements in a well tested and timely manner.
This paper describes the sequential processes in the DDIP methodology and further discusses specific engineering problems and solutions using the DDIP process.
MS5002 Advanced Technology Uprate and Field Modification Experience
Authors: Ismoyo  , Kinney Carl D. , Grondahl Clayton M. 
Published: March 2015

Advanced Technology turbine components have been developed for the GE MS5002 line of gas turbines that permit operation at a higher firing temperature. Those components include directionally solidified (DS) GTD-111 alloy stage-one buckets — the first GE application of a DS alloy in heavy-duty gas turbines. The Advanced Technology uprate improves turbine performance and extends turbine inspection intervals.
This paper provides an overview of the field modification of 21 mechanical drive units in Indonesia. The user’s technical objectives and uprate requirements are discussed along with installation experience and operating results to date. Advanced Technology component design features are illustrated and discussed in some detail with reference to their application in field units.
The VKI Compression Tube Annular Cascade Facility CT3
Authors: Sieverding C. H. , Arts T. 
Published: March 2015

The purpose of this paper is to present the new transonic, annular facility developed at the von Karman Institute to investigate the aerodynamic heat transfer performances of real size advanced aero-engine and gas turbine components at correctly simulated operating conditions.
The facility operates under the principle of an Isentropic Light Piston Compression Tube. Its definite advantage over classical blowdown wind tunnels is to independently model the freestream Mach and Reynolds numbers as well as the gas/wall/coolant temperature ratios. Its running time ranges between 0.1 and 1 s.
The first part of the paper describes the design, the manufacturing and the installation of the different components of the wind tunnel and the test section. The second part deals with the different measurement techniques applied for aerodynamic and heat transfer measurements; it also describes some examples of the flow quality obtained in this new facility.
Trial Operations of Unit No. 1 Group 690 MW Combined Cycle Power Plant of Shin-Oita Power Station
Authors: Nogami S. , Ando N. , Noguchi Y. , Takahashi K. , Iwamiya T. , Hattori Y. 
Published: March 2015

Kyushu Electric Power Co., Inc., in constructing the recently completed first phase of the No. 1 Group of Shin-Oita Power Plant, Oita Prefecture (Kyushu Island), achieved further improvements over previous combined cycle plants, especially in the area of plant overall operation. It is composed of six combined cycle power units of the single-shaft, non-reheat type, based on Hitachi-GE MS7001E gas turbines, with a total output of 690 MW.
Trial operations of the first unit began in May, 1990. Commercial operations of the first unit began in November 1990, and the last unit in June, 1991.
The NO.1 Group incorporates two major advances over previous combined cycle plants.
The first advance is a two-stage multiple nozzle dry-type low-NOx combustor. This combustor is a new development for keeping the level of NOx emissions below 62.5 ppm (16% O2 at gas turbine exhaust).
The second advance is a new functionally and hierarchically distributed digital control system. By the control system, the plant was designed to bring the following notable features:
1 The individual units can be started and stopped automatically from the load dispatching directive center at the head office.
2 The plant can be operated for high efficiency with short starting and stopping time and large load variations.
3 Plant operating characteristics for emergency operations can be improved remarkably, for instance, load run back operations and fast cut back operation, etc.
The results of trial operations have shown that the output per unit is about 0.5 to 4.2% higher, and the unit efficiency about 1.9 to 3.7% higher, than the planned values (all percentages relative), and tangible improvements and starting characteristics and load fluctuation are also satisfactory with the specified target values in the overall operation of the plant over that of previous combined cycle power plants.
This plant has satisfactorily been operated since the start of commercial operation.
Performance of Gas Turbine Compressor Cleaners
Authors: Kolkman H. J. 
Published: March 2015

Deposits are regularly removed from compressor blades and vanes of installed jet engines and gas turbines by compressor washing. Hereby a compressor cleaner is sprayed into the compressor while operating at reduced or normal r.p.m.
Recently developed compressor cleaners are claimed to be ecologically sound. In addition, many new compressor cleaners contain a corrosion inhibitor.
The cleaning efficiency of eight (old and new) compressor cleaners was determined by means of simulated compressor washing of compressor blades that had become foul in service. For the situation simulated, the cleaning efficiency of new, ecologically sound cleaners turned out to be poor as compared with old compressor cleaners.
The corrosion inhibition offered by those cleaners that contain a corrosion inhibitor was found to be satisfactory.
Combined Cycle Power Plant Start-Up Effects and Constraints of the HRSG
Authors: Pasha Akber 
Published: March 2015

The heat recovery steam generator (HRSG) is an integral part of the combined cycle power plant which includes combustion turbine and steam turbine in addition to heat recovery steam generator. The start-up of the heat recovery steam generator, therefore, has an influence on the start-up of the total plant.
The paper discusses various constraints, both external and internal, which affect the Steam Generator start-up and in turn influence the start-up of the total plant. Considerations in the design of the steam generator to accommodate the plant start-up requirements, along with the effect of the cyclic or base loaded operation are also discussed.
The paper also presents a procedure which may be adopted in the conceptual design of the plant for an optimized system, a system which can accommodate the total plant start-up requirements without undue constraints on the availability of the full plant output.
Flow Studies in Ducted Twin-Rotor Contra-Rotating Axial Flow Fans
Authors: Roy Bhaskar , Ravibabu K. , Rao P. Srinivasa , Basu S. , Raju A. , Murthy P. N. 
Published: March 2015

The design and testing of a 400 mm diameter contra-rotating fan unit was undertaken to study the flow behavior through the contra-rotating fans, and to find ways and means of improving their design and performance. The performance characteristics of the two-fan unit have shown that large overall stall margins can be achieved. Also, the effect of axial gaps showed that at the design speed combination best performance was observed at an axial gap of 50% of the 1st Fan chord.
Studies on the 2nd fan exit flow field, performance characteristics of individual fans and casing boundary layer development have been made. Significant performance enhancement is observed with serration on 2nd fan rotor blade surface. When casing boundary layer suction is employed in between the two blades, the 2nd fan exit flow shows better uniformity and increased total pressure at all radii. However, to obtain a large operating range, careful optimization of the 2nd rotor blade design would be required, taking into account peculiarities shown by the present study in variation of deviation and exit flow angles of the individual fans, and casing boundary layer development with increased axial pressure gradient.
Applications of Sound Intensity Measurements to Gas Turbine Engineering
Authors: Rawlinson R. D. 
Published: March 2015

Recent advances in signal processing techniques have made the measurement of sound intensity a practical reality. The newly developed sound intensity meters can indicate both the magnitude and direction of sound. This is a major advantage over the traditional sound level meter which does not have such directional sensitivity. Sound intensity meters can, therefore, make accurate measurements under adverse conditions, such as onshore or offshore, where sound level meters may be unsuitable.
This makes the detailed assessment of the sound power output of a gas turbine package, operating in the field, practicable. Individual components of a gas turbine train can be evaluated so that the dominant noise sources can be identified, thereby providing more cost effective solutions to onshore and offshore installations.
This paper describes briefly the concepts of sound intensity, the current state of standards and some aspects of measurement technique. Case histories of the use of sound intensity instrumentation in a variety of situations, relevant to gas turbine engineering, will be described. This will include laboratory and field based investigations.
An Optimisation-Matching Procedure for Variable Cycle Jet Engines
Authors: Nascimento Marco A. R. , Pilidis Pericles 
Published: March 2015

There are many advantages in employing Variable Cycle Engines for aircraft propulsion. These engines operate with two or more thermodynamic cycles, each suited to certain flight conditions.
One of the greatest challenges, during the design phase, is how to optimise the various cycles and then to match them to the capabilities of the components which make up the engine.
In this paper a general method is presented to carry out this exercise. The method is based on thermodynamic relationships and component characteristics. An example is included to illustrate the procedure.
Some Aspects of Variable Geometry Gas Turbine Operation
Authors: Roy-Aikins J. E. A. 
Published: March 2015

Many gas turbine thermodynamic cycles have been proposed which were designed to meet the propulsion requirements of future advanced aircraft. A thoughtful consideration of such designs is warranted as engines operating on such cycles will give a significant improvement in off-design performance. Such performance improvements can be brought about chiefly by the extensive use of variable geometry components. With the advent of the variable area turbine, a greater flexibility will be obtained in engine control and, hence, in aircraft operation.
This paper examines the performance of a variable geometry engine that is suitable for V/STOL aircraft operation, and it discusses how certain aerodynamic and mechanical phenomena associated with variable area turbines may influence the design and limit the operation of future advanced gas turbines.
Using Contra-Rotating Rotors for Decreasing Sizes and Component Number in Small GTE
Authors: Ponomariov B. A. , Sotsenko Y. V. 
Published: March 2015

Using the contra-rotating high and low rotors influences effectively on the turbocompressor parameters and configuration and improves its mass-dimension characteristics and reduces in component number if the required level of the fuel efficiency is provided. Two groups of the engines: 400–1000 shp class and 1000–2000 shp class are chosen with allowance for the small GTE specificity. Conformably to first group the influence of the gas generator turbine (GGT) diameter on the possibility of obtaining the optimal combination of the GGT wheel blade gas dynamic loading, clearance losses and flow swirl before the power turbine (PT) is studied. Used for the second group is the approach of which the main point lies in the utilization of a high-loading, single-stage GG turbine, permitting the cooling air flow to be reduced (or the gas temperature to be increased) and the flow swirl before the PT to be profitably realized against the engine having two-stage GGT.
The key point while solving the specified problem is the gas dynamic characteristics of the engine hot section and its influence on the engine parameters. The investigations are carried out in the engine system using the experimental data on the losses in the rectilinear turbine cascades of the slightly curved profiles.
Erosion Resistant Titanium Nitride Coating for Turbine Compressor Applications
Authors: Liburdi J. , Nagy D. R. , Parameswaran V. R. 
Published: March 2015

While operating in dusty environments, the blades and vanes in turbine compressors are prone to degradation by solid particle erosion which causes surface roughening as well as loss of airfoil contour and changes in airfoil geometry. This results in decreased compressor performance, higher specific fuel consumption, and significantly increased operational costs. Erosion damage is more prominent in flight engines that cannot be protected by inlet filters.
This paper describes the development and application of a thin ceramic titanium nitride coating to improve the erosion resistance of compressor airfoils. The coatings were produced by a Reactive Ion Coating (RIC) process and optimized to produce a very adherent erosion resistant coating structure.
The coating process was successfully scaled up and applied to a complete Allison T56 compressor for engine test. The control laboratory tests showed that the thin coating had no significant influence on either the resonance frequency or the fatigue resistance of the blades and the instrumented engine tests confirmed that the performance was typical of overhauled engines. Therefore, titanium nitride coatings are suitable for service and can be retrofitted on existing engines to improve the life of the compressors.
30S Subunit-Dependent Activation of the Sorangium cellulosum So ce56 Aminoglycoside Resistance-Conferring 16S rRNA Methyltransferase Kmr
Authors: Savic Miloje , Sunita S. , Zelinskaya Natalia , Desai Pooja M. , Macmaster Rachel , Vinal Kellie , Conn Graeme L. 
Published: March 2015

ABSTRACT

Methylation of bacterial 16S rRNA within the ribosomal decoding center confers exceptionally high resistance to aminoglycoside antibiotics. This resistance mechanism is exploited by aminoglycoside producers for self-protection while functionally equivalent methyltransferases have been acquired by human and animal pathogenic bacteria. Here, we report structural and functional analyses of the
Sorangium cellulosum
So ce56 aminoglycoside resistance-conferring methyltransferase Kmr. Our results demonstrate that Kmr is a 16S rRNA methyltransferase acting at residue A1408 to confer a canonical aminoglycoside resistance spectrum in
Escherichia coli
. Kmr possesses a class I methyltransferase core fold but with dramatic differences in the regions which augment this structure to confer substrate specificity in functionally related enzymes. Most strikingly, the region linking core β-strands 6 and 7, which forms part of the
S
-adenosyl-
l
-methionine (SAM) binding pocket and contributes to base flipping by the m
1
A1408 methyltransferase NpmA, is disordered in Kmr, correlating with an exceptionally weak affinity for SAM. Kmr is unexpectedly insensitive to substitutions of residues critical for activity of other 16S rRNA (A1408) methyltransferases and also to the effects of by-product inhibition by
S
-adenosylhomocysteine (SAH). Collectively, our results indicate that adoption of a catalytically competent Kmr conformation and binding of the obligatory cosubstrate SAM must be induced by interaction with the 30S subunit substrate.
Mass Spectrometry Imaging Reveals Heterogeneous Efavirenz Distribution within Putative HIV Reservoirs
Authors: Thompson Corbin G. , Bokhart Mark T. , Sykes Craig , Adamson Lourdes , Fedoriw Yuri , Luciw Paul A. , Muddiman David C. , Kashuba Angela D. M. , Rosen Elias P. 
Published: March 2015

ABSTRACT
Persistent HIV replication within active viral reservoirs may be caused by inadequate antiretroviral penetration. Here, we used mass spectrometry imaging with infrared matrix-assisted laser desorption–electrospray ionization to quantify the distribution of efavirenz within tissues from a macaque dosed orally to a steady state. Intratissue efavirenz distribution was heterogeneous, with the drug concentrating in the lamina propria of the colon, the primary follicles of lymph nodes, and the brain gray matter. These are the first imaging data of an antiretroviral drug in active viral reservoirs.
Effects of Azithromycin, Metronidazole, Amoxicillin, and Metronidazole plus Amoxicillin on anIn VitroPolymicrobial Subgingival Biofilm Model
Authors: Soares Geisla M. S. , Teles Flavia , Starr Jacqueline R. , Feres Magda , Patel Michele , Martin Lynn , Teles Ricardo 
Published: March 2015

ABSTRACTChronic periodontitis is one of the most prevalent human diseases and is caused by dysbiosis of the subgingival microbiota. Treatment involves primarily mechanical disruption of subgingival biofilms and, in certain cases, adjunctive use of systemic antibiotic therapy.In vitrobiofilm models have been developed to study antimicrobial agents targeting subgingival species. However, these models accommodate a limited number of taxa, lack reproducibility, and have low throughput. We aimed to develop anin vitromultispecies biofilm model that mimics subgingival plaque, to test antimicrobial agents. Biofilms were cultivated using the Calgary Biofilm Device and were exposed to amoxicillin (AMX), metronidazole (MTZ), azithromycin (AZM), and AMX-MTZ at four different concentrations for 12, 24, or 36 h. Chlorhexidine (CHX) (0.12%) was used as the positive control. The compositions of the biofilms were analyzed by checkerboard DNA-DNA hybridization, and the percent reduction in biofilm metabolic activity was determined using 2,3,5-triphenyltetrazolium chloride and spectrophotometry. Thirty-five of the 40 species used in the inoculum were consistently recovered from the resultingin vitrobiofilms. After 36 h of exposure at the 1:27 dilution, AMX-MTZ reduced metabolic activity 11% less than CHX (q= 0.0207) but 54% more than AMX (q= 0.0031), 72% more than MTZ (q= 0.0031), and 67% more than AZM (q= 0.0008). Preliminary evidence of a synergistic interaction between AMX and MTZ was also observed. In summary, we developed reproducible biofilms with 35 subgingival bacterial species, and our results suggested that the combination of AMX and MTZ had greater antimicrobial effects on thesein vitromultispecies biofilms than expected on the basis of the independent effects of the drugs.
Heteroresistance to Colistin in Klebsiella pneumoniae Associated with Alterations in the PhoPQ Regulatory System
Authors: Jayol Aurélie , Nordmann Patrice , Brink Adrian , Poirel Laurent 
Published: March 2015

ABSTRACT

A multidrug-resistant
Klebsiella pneumoniae
isolate exhibiting heteroresistance to colistin was investigated. The colistin-resistant subpopulation harbored a single amino acid change (Asp191Tyr) in protein PhoP, which is part of the PhoPQ two-component system that activates
pmrHFIJKLM
expression responsible for
l
-aminoarabinose synthesis and polymyxin resistance. Complementation assays with a wild-type
phoP
gene restored full susceptibility to colistin. Then, analysis of the colistin-susceptible subpopulation showed a partial deletion (25 bp) in the
phoP
gene compared to that in the colistin-resistant subpopulation. That deletion disrupted the reading frame of
phoP
, leading to a longer and inactive protein (255 versus 223 amino acids long). This is the first report showing the involvement of mutation(s) in PhoP in colistin resistance. Furthermore, this is the first study to decipher the mechanisms leading to colistin heteroresistance in
K. pneumoniae
.
Impact of β-Lactamase Inhibition on the Activity of Ceftaroline against Mycobacterium tuberculosis and Mycobacterium abscessus
Authors: Dubée Vincent , Soroka Daria , Cortes Mélanie , Lefebvre Anne-Laure , Gutmann Laurent , Hugonnet Jean-Emmanuel , Arthur Michel , Mainardi Jean-Luc 
Published: March 2015

ABSTRACT

The production of β-lactamases Bla
Mab
and BlaC contributes to β-lactam resistance in
Mycobacterium abscessus
and
Mycobacterium tuberculosis
, respectively. Ceftaroline was efficiently hydrolyzed by these enzymes. Inhibition of
M. tuberculosis
BlaC by clavulanate decreased the ceftaroline MIC from ≥256 to 16 to 64 μg/ml, but these values are clinically irrelevant. In contrast, the ceftaroline-avibactam combination should be evaluated against
M. abscessus
since it inhibited growth at lower and potentially achievable drug concentrations.