bluuebunny/crossref_metadata_2025_split huggingface dataset:
Computational analysis of mutated AHAS in response to sulfonylurea herbicides
Authors: Choe M , Choe W , Lee I , Wu M , Liu S 
Published: March 2015

SummarySulfonylurea (SU) herbicides that target acetohydroxyacid synthase (AHAS, also called acetolactate synthase (ALS)) are regarded as one of the most important classes of herbicides, due to their extremely low toxicity towards mammals, ultra‐low dosage application and high selectivity. However, mutations of AHAS to a herbicide‐insensitive form appear to be a worldwide problem for acquired resistance. In this study, three mutated AHAS sequences were used. In the mutated AHASs, the proline (Pro) was replaced by one of threonine (Thr), alanine (Ala) or serine (Ser) in AHAS amino acid (AA) position 197Pro. To understand the herbicide resistance mechanism, we built dimeric AHAS complex models based on 1YBH of protein data bank (PDB) with SU herbicide, chlorimuron ethyl (CIE), using a homology. The three mutated AHASs in complex with CIE were analysed, and the resistance mechanism to SU herbicides was studied by molecular dynamics (MD) simulation performed using GROMACS 4.5.5. MD simulation analysis of wild‐type and the three mutated dimeric AHAS–CIE complex systems revealed the conformational stability and changes in herbicide binding to dimeric AHAS system due to the mutation. Additionally, it showed that conformational change of amino acid residue 200Met (methionine) was associated with the imidazolinone herbicide resistance mechanism. According to our computation, the detailed mechanism of herbicide resistance was variable, depending on the type of mutated amino acid, providing new insights for designing herbicides specific to each mutant AHAS.
Accumulation of ceramide in slow‐twitch muscle contributes to the development of insulin resistance in the obese JCR:LA‐cp rat
Authors: Fillmore Natasha , Keung Wendy , Kelly Sandra E. , Proctor Spencer D. , Lopaschuk Gary D. , Ussher John R. 
Published: March 2015

New Findings

What is the central question of this study?
The aim was to determine whether the accumulation of ceramide contributes to skeletal muscle insulin resistance in the JCR obese rat.

What is the main finding and its importance?
Our main new finding is that ceramides accumulate only in slow‐twitch skeletal muscle in the JCR obese rat and that reducing ceramide content in this muscle type by inhibition of serine palmitoyl transferase‐1 halts the progression of insulin resistance in this rat model predisposed to early development of type 2 diabetes. Our findings highlight the importance of assessing insulin signalling/sensitivity and lipid intermediate accumulation in different muscle fibre types.

It has been postulated that insulin resistance results from the accumulation of cytosolic lipid metabolites (i.e. diacylglycerol/ceramide) that impede insulin signalling and impair glucose homeostasis. De novo ceramide synthesis is catalysed by serine palmitoyl transferase‐1. Our aim was to determine whether de novo ceramide synthesis plays a role during development of insulin resistance in the JCR:LA‐cp obese rat. Ten‐week‐old JCR:LA‐cp obese rats were supplemented with either vehicle or the serine palmitoyl transferase‐1 inhibitor l‐cycloserine (360 mg l−1) in their drinking water for a 2 week period, and glycaemia was assessed by meal tolerance testing. Treatment of JCR:LA‐cp obese rats with l‐cycloserine improved their plasma glucose and insulin levels during a meal tolerance test. Examination of muscle lipid metabolites and protein phosphorylation patterns revealed differential signatures in slow‐twitch (soleus) versus fast‐twitch muscle (gastrocnemius), in that ceramide levels were increased in soleus but not gastrocnemius muscles of JCR:LA‐cp obese rats. Likewise, improved glycaemia in l‐cycloserine‐treated JCR:LA‐cp obese rats was associated with enhanced Akt and pyruvate dehydrogenase signalling in soleus but not gastrocnemius muscles, probably as a result of l‐cycloserine reducing elevated ceramides in this muscle type. Potential mechanisms of ceramide‐mediated insulin resistance involve activation of atypical protein kinase Cζ/λ and protein phosphatase 2A; however, neither of these was altered in muscles of JCR:LA‐cp obese rats. Our results suggest a key role for ceramide in the development of insulin resistance in the JCR:LA‐cp obese rat, while supporting serine palmitoyl transferase‐1 inhibition as a novel target for treatment of obesity‐associated insulin resistance.
The Modernization of a 1965, MS5001, Gas Turbine: New Life for an Old Unit
Authors: Grondahl Clayton M. , Linnell Renard D. , Martin Tommy J. 
Published: March 2015

Application of the GE MS5001 gas turbine performance improvement uprate package has been extended to an early model “K” unit at Texaco’s Convent, LA refinery. This extensive modification required replacement of the turbine shell in addition to the installation of new technology components developed for more recent MS5001 models.
This paper presents the customer’s motivation to refurbish a 22 year old gas turbine. Gas turbine component design improvements and interfaces are discussed with performance and reliability gains. Field service engineering experience installing the uprate is also related.
A Transient Flow Facility for the Study of the Thermofluid-Dynamics of a Full Stage Turbine Under Engine Representative Conditions
Authors: Ainsworth R. W. , Schultz D. L. , Davies M. R. D. , Forth C. J. P. , Hilditch M. A. , Oldfield M. L. G. , Sheard A. G. 
Published: March 2015

The design and construction of a new experiment, to investigate the steady and unsteady heat transfer and aerodynamic behaviour of a rotating turbine in a transient facility, is described. The need for this experiment is discussed in the context of previous rotating bar wake and shock simulation work carried out in the Oxford transient cascade facility, and research elsewhere on the effects of rotating and three-dimensional flowfields on turbine aerodynamics and heat transfer.
The outline concept and mode of operation of the turbine module are given before novel features of the design are presented in detail. Reference is made to a parallel paper also presented at this conference[18] which gives full details of the developments that have been necessary to allow the measurement of steady and unsteady heat transfer in this facility.
Finally, the future work programme and possible plans for further facility improvements are given.
Notes on the Occurrence and Determination of Carbon Within Gas Turbine Combustors
Authors: Odgers J. , Magnan E. R. 
Published: March 2015

Details are presented of two series of experiments to investigate carbon determination in gas turbine combustion chambers. The first series employed a gravimetric technique to examine carbon distribution within the various zones of a combustor with the aim of identifying zones of formation and oxidation.
In the second series a fairly comprehensive investigation of the technique of measuring Smoke Number was made with the objective of obtaining details relevant to its accuracy and applicability. Mixtures of iso-octane and benzene were used as fuel, thereby permitting the effects of hydrogen content to be established. The results are correlated with othersome obtained previously.
Gas Turbine Systems for World Navy Ships
Authors: Brady Eugene F. 
Published: March 2015

The application of gas turbines for propulsion of navy ships for all nations continues to increase at an accelerating rate. World navies which use gas turbines include the United States, Great Britain, the Soviet Union and Japan. Therefore, a survey of the principal gas turbine applications in world navies was conducted.
This survey revealed that more than 43 world navies now use gas turbines for ship propulsion. It also indicated that more than 2,700 gas turbines have been (or soon will be) installed in world navy ships. This represents a total worldwide navy application exceeding 38 million installed horsepower.
Two Case Studies of Cogeneration in India
Authors: Shome S. K. , Ganguly P. K. 
Published: March 2015

The steam and electric power requirement for an industrial complex can be integrated in a cogeneration system achieving improved efficiency at comparatively lower plant costs.
Various technical and economic parameters of a cogeneration plant in a petrochemical plant and a refinery in India are discussed. Both applications use industrial gas turbine and heat recovery boilers with supplementary firing using gaseous and/or liquid fuel.
For the petrochemical complex, two 25 MW (ISO) industrial gas turbines and two 75 tonnes/hr. heat recovery boilers with provision for supplementary firing were selected to meet the 37 MW power demand and 150 tonnes/hr. (low pressure, saturated) steam demand. The plant is designed for natural gas fuel. The unit tested better than guaranteed.
For the refinery application, two 25 MW (ISO) industrial gas turbines and two heat recovery boilers with supplementary firing were selected to meet a normal steam demand of 90 tonnes/hr. with a peak of 120 tonnes/hr. and a critical power demand of 15.6 MW with a normal demand of 22 MW. The fuel to be used is gas and/or distillate oil. The guaranteed plant efficiency was quoted as 79.25% (on L.H.V. basis). The plant is under construction and expected to go on line in early 1988.
The Oil-Free Shaft Line
Authors: Wagner Bruno 
Published: March 2015

This paper recalls the principles and main features of the active magnetic bearings and especially the advantages for turbomachines. Oil-free working and vibration control are part of them.
Field experiences are described for different shaft line configurations. Step by step we are going to get totally rid of oil with the introduction of active magnetic bearings together with dry gas seals and gearless drive. Future machines will take the benefit of all this field experience. The trend of the design optimization is the active magnetic bearings in the process gas itself, for a length reduction of shafts. But at the present stage, the active magnetic bearing is a proven technology today.
1000 Hour Qualification Test of the Textron Lycoming TF40B Marine Gas Turbine Engine for the U.S. Navy LCAC Craft
Authors: Zoccoli Michael J. 
Published: March 2015

This paper describes the qualification testing of the TF40B marine gas turbine in accordance with the duty cycle as specified in MIL-E-17341C, but with modifications that reflect the specific engine application to the U.S. Navy LCAC vehicle.
Among the particular requirements of the 1000 hour test are continuous operation in a salt-laden environment of given concentration and humidity, and frequent shutdowns from relatively high power with an ensuing soakback interval.
The narrative discusses the method of test, the duty cycle, and the results which were obtained.
In an epilogue which focuses on posttest activities, a description is given of the corrective actions taken to resolve certain problems that arose during the course of the test. One such problem, namely the occurrence of carbon erosion upon certain hot section components, was eliminated by modification to the combustor, in a very successful posttest test development program.
Brushes as High Performance Gas Turbine Seals
Authors: Ferguson J. G. 
Published: March 2015

Brush seals are the first simple and practical alternative, to the finned labyrinth, for gas turbine air system seals. Their use has been made possible by a combination of innovative design features, combined with advanced materials and manufacturing techniques.
Due to the very high rubbing speeds and temperatures, existing in gas turbine air system seal positions, finned labyrinths have been used almost exclusively since the invention of the gas turbine. Development over the years has reduced their leakage flow to the ultimate, but leakage is very much dependent on clearance. A brush seal, replacing the best possible finned labyrinth seal, needing a clearance of 0.7mm, can reduce the flow to approximately 10% of that of the finned seal.
The main advantages of brush seals, therefore, are their dramatic improvement in sealing performance. This is combined, however, with their ability to maintain this performance even during and after transient differential movements. These advantages have been developed and demonstrated after many hours rig and engine running.
Back to back engine tests, with brush seals, replacing finned labyrinths in key air system seals, have demonstrated a significant improvement in thrust for a given stator outlet temperature (SOT).
Flight trials are in progress, on an engine fitted with brush seals, as a further step to their in service use.
New Erosion Resistant Compressor Coatings
Authors: Kolkman H. J. 
Published: March 2015

Airfoils of gas turbines and jet engines frequently deteriorate by erosion or corrosion: Protection can be offered by special coatings that are resistant to either erosion or corrosion. However, the conventional corrosion resistant compressor coatings have very poor erosion resistance. Therefore there is a tendency to apply compressor coatings that offer protection against both erosion and corrosion.
The erosion resistance of (improved) conventional aluminium-based compressor coatings and of new TiN, Ti2B and WC coatings was determined at 150° C as a function of the angle of attack. The Ti2B coating had especially promising erosion resistance.
Theoretical Investigation of the Interaction Between a Compressor and the Components During Surge
Authors: Brumm Jürgen , Kalac Hassan , Teipel Ingolf 
Published: March 2015

Problems of compressor instability have been of concern not only to aircraft engine designers but also for example to operators of industrial power plants. Two types of flow instabilities are known and in this paper only one of them, the surge phenomenon, will be discussed in detail. For the occurence of these heavy pressure fluctuations the volume of the neighbouring plenum chamber is the important quantity.
Here the basic compression system consisting of a compressor, a duct and a plenum will be analysed in order to show the complete unsteady pressure field. The theoretical model is based on the application of mass, momentum and energy conservation equations of one-dimensional flow. The set of differential equations of hyperbolic type is solved numerically by a ‘predictor-corrector’ scheme. The method itself is an explicit procedure first given by MacCormack /9/. At the interfaces between two components the coupling conditions for pressure and flow velocity are taken from the method of characteristics. The behaviour of the compressor is determined by its performance map, which describes the relationship between pressure and mass flux for all conditions from stable performance to inverse mass flow. For the dynamic change of the pressure development a special compressor characteristic taking into account the unsteady effects is used. This model function is chosen according to a time lagging element often employed in control theory.
To demonstrate the capability of the described method variations of different parameters such as mass flow rate, volume behind the compressor, ect. will be presented. The pressure-time history will be compared with experimental data published in the literature. Also the calculated surge frequencies, will be discussed. Furthermore it will be examined how a working point of the compressor moves from a stable part of the characteristic to another one, stable or unstable. Finally the general time dependent surge performance is considered in comparison to the quasi-steady characteristic.
Comparison of Ceramic vs. Advanced Superalloy Options for a Small Gas Turbine Technology Demonstrator
Authors: Bornemisza T. , Napier J. 
Published: March 2015

The next generation of small gas turbines used as compact Auxiliary Power Units (APUs) in aircraft and mobile ground power applications will achieve higher power density than current installations by operating at substantially higher turbine inlet temperatures. Ceramics vs. advanced/cooled superalloy designs are compared as alternate paths to improved performance through increased turbine inlet temperature for the T-100 MPSPU (Multi-purpose Small Power Unit) technology demonstrator engine currently under development.
Past experience at Sundstrand Turbomach in demonstrating ceramic and air cooled components is used to project level of success expected in meeting the demonstrator engine performance goals with either ceramics or advanced/cooled superalloy radial turbine nozzle and turbine wheel. The alternate designs are compared in terms of potential against such criteria as performance, power density and cost.
Review of Design Parameters in Gas Turbines for the Prospective User
Authors: Dundas Robert E. 
Published: March 2015

This paper is based on five selected areas of gas turbine design that should be reviewed by prospective purchasers of gas turbines in the specification and procurement phase, in view of adverse industry experience associated with them. The details that should be requested and reviewed, and the criteria that should be met, are discussed. Case histories of adverse industry experience are provided for substantiation of the recommendations.
The design areas discussed are:
1. Compressor-blade resonance diagrams
2. Compressor performance maps
3. Turbine-blade resonance diagrams
4. Temperature profiles in turbine flowpath
5. Response to combustor flameout
Coal Oxidation
Authors: Raj S. 
Published: March 2015

Coals contain considerable amounts of oxygen in their structures ranging from 30% in brown coal to about 1.5% in anthracites. The distribution of coal oxygen in various functionalities changes drastically with increasing rank. The hetero-atom functionalities in coal and coal products are of importance in the processing of coal. The process of coal conversion relevant to the steam and gas turbine applications are pyrolysis, oxidation and combustion processes. Initial stages of pyrolysis and oxidation (combustion) are the thermal decomposition of the solid coal matrix to free radicals. Oxygen, sulfur, nitrogen and mineral containing free radicals play an important role during combustion thermodynamically. The differences between the coal functionalities in the solid coal matrix contribute to oxidation reactions of first and second order. The first and second order reactions affect the corrosion and deposition rates of the machine components differently.
In this paper functionality differences of various coals with respect to their oxidation characteristics will be discussed.
Operating Experience With Type H Industrial Gas Turbines on North Sea Platforms
Authors: Cullen J. P. 
Published: March 2015

The paper outlines the operating and maintenance experience of the TYPE H industrial gas turbines on 2 of the platforms in the Greater Ekofisk field on the Norwegian continental shelf.
Traditional preventive maintenance procedures based on elapsed fired hours are discussed. Availability and reliability statistics are presented.
Typical component replacement on inspections is tabulated and comments are given.
Finally the author describes an on line, computer supervised, condition monitoring system which is being used and will help replace traditional preventive maintenance with predictive maintenance.
A Secondary Flow Calculation Method Based on the Meridional Vorticity Transport Equation
Authors: Kaldellis J. , Douvikas D. , Papailiou K. D. 
Published: March 2015

A secondary flow calculation method is presented in this work, which makes use of the meridional vorticity transport equation. Circumferentially mean flow quantities are calculated using an inverse procedure.
The method makes use of the mean kinetic energy integral equation and calculates simultaneously hub and tip secondary flow development. Emphasis is placed upon the use of a coherent two-zone model and particular care is taken in order to describe adequately the flow inside an unbounded (external), semi-bounded (annulus) and fully-bounded (bladed) space. The velocity field, the losses and the defect forces receive particular attention.
Comparison between theoretical and experimental results is presented.
Structural Design and its Improvements Through the Development of the XF3-30 Engine
Authors: Kikuchi Hidekatsu , Ishii Kiyoshi 
Published: March 2015

The XF3-30 engine has been successfully completed its Qualification Test at March 1986 and the production has started as the powerplant for Japan Self Defence Force’s intermedeate trainer T-4. The first flight of the T-4 powered by two XF3-30 engine was made on the 29th July 1985. More than 500 test flights have been made in these two years and engine flight time has accumulated to over 1,500 hours.
This XF3-30 engine has been imposed strict requirements of the structural integrity to meet the MIL-E-5007D specification. This paper describes the structural features of this engine and some structural problems encountered through the development. The improvements for these development problems are covered.
A New Approach to the Calculation of S2 Stream Surfaces With Full Inverse and Hybrid Methods for Turbomachine
Authors: Manchu Ge , Zhengti Yu , Yiping Lou 
Published: March 2015

In this paper, a full Inverse problem method — a prescribed wall-velocity method (PWVM) — and a hybrid problem method are suggested in solving S2 stream surface. In these methods two walls or one wall coordinates of the meridional through flow section of turbomachine can be obtained when the velocities along the hub and casing walls or one of them are prescribed. The new form of the governing equations in terms of grid coordinates are obtained. These equations are different with those used for the S1 stream surfaces. The suitable wall-velocities can be selected and prescribed by designer and the coordinates of hub and casing walls will be obtained by solving these new equations on S2 stream surfaces. The boundary conditions and the solution of these equations will be presented too.
The programs have been written and several examples are calculated. The results seems to be satisfactory. A comparison between the solutions of this method and the ordinary method, which is a method given the coordinates of hub and casing walls, is also presented in this paper.
Design Aspects of Recent Developments in Rolls-Royce RB211-524 Powerplants
Authors: Parkes R. J. 
Published: March 2015

This paper describes recent design changes in the RB211-524 powerplant. In response to the market requirement for a wide bodied aircraft to make journeys of increased range, the specific fuel consumption of the latest -524 engine has been improved by 14% compared with initial versions.
The paper shows how the potential of the three shaft concept has been coupled with the latest aerodynamic technology to produce over 25% more thrust at essentially the same engine size. This increased thrust has been achieved while meeting the latest noise and gaseous emissions regulations and while achieving continuing improvements in engine reliability.
The paper describes the introduction of electronic engine control to provide improved aircraft operation and maintenance. It also shows how the needs of the latest wide body, long range, twin engined aircraft under development can be met by combining the core of the -524 engine with a larger fan to produce a powerplant with a further 25% increased thrust capability.