bluuebunny/crossref_metadata_2025_split huggingface dataset:
A GCC Power Plant With Methanol Storage for Intermediate-Load Duty
Authors: Paffenbarger John A. 
Published: March 2015

This paper describes the design and performance of a coal gasification combined-cycle power plant with an integrated facility for producing and storing methanol (GCC/methanol power plant). The methanol is produced at a steady rate and is burned in the combined-cycle to generate additional power during periods of peak electrical demand. The GCC/methanol plant provides electricity generation and energy storage in one coal-based facility. It is of potential interest to electric utilities seeking to meet intermediate-load electrical demand on their systems.
The plant configuration is determined by means of an economic screening study considering capital and fuel costs over a range of cycling duties (load factors). Estimated levelized electricity production costs indicate that a GCC/methanol plant could be of economic interest as premium fuel prices increase relative to coal. The plant could potentially be of interest for meeting daily peak demands for periods of eight hours or less.
The conceptual plant configuration employs a Texaco gasifier and a Lurgi methanol synthesis plant. Plant performance is estimated at peak and baseload output levels. No unusual design or operational problems were identified.
Improvements in Incinerators by Means of Gas Turbine Based Cogen Systems
Authors: Wiekmeijer Ir. Ted 
Published: March 2015

In this paper a new process is described to improve the efficiency of power generation in waste incineration plants. It is proposed to superheat the steam in a gas turbine/waste heat boiler combination rather than in the incinerator boiler.
Although this is not discussed in this paper the same process may be applied in nuclear power stations where the superheating of steam is also a problem.
A global risk-analysis of the addition of equipment is made in this paper. On basis of a case-study the financial advantages are demonstrated.
Control System Design: Gas Turbine Machinery: The Use of a Corporate Model for Control System Design
Authors: Girolami Silvio 
Published: March 2015

This paper describes a systematic, consistent approach to control design developed over years of theoretical design and field testing. The Gas Turbine Generator Set control (with some Hover-craft Lift control variations) is discussed both as an example of the design method and as a project on its own merit.
This control ideology is not dependent on implementing hardware, high level languages. It is an organic method based on an example of “human” organization, the corporation. The Gas Turbine control is an interactive corporate team; member personalities and duties are the logic.
The rationalized I-T-E (if-then-else) method of defining and programming the control (corporate) personalities is used by the turbine and controls engineers to efficiently produce the final turbine and machinery control algorithms.
A simple integrated software/hardware scheme facilitates recording and executing these algorithms.
Last but not least, reliable control performance must be achieved through an inherently fail-safe “systems” approach.
Design and Performance Features of the Marine LM1600 Gas Turbine
Authors: Thames J. M. , Stueber H. B. , Vincent C. T. 
Published: March 2015

The GE LM1600 gas turbine is a lightweight, efficient prime mover for commercial and military marine applications. This gas turbine is a derivative of the F404 fighter jet engine whose mission objectives strongly emphasize reliability and ease of maintenance in an austere marine environment. These objectives were important to the U.S. Navy because the F/A-18 fighter jets powered by this engine are based on aircraft carriers where parts warehousing and maintenance capabilities are limited. To achieve these objectives, component designs were simplified and the total number of components was substantially reduced.
These features and its modular construction make the LM1600 attractive for marine applications. Numerous marine propulsion system configurations are possible, including various combinations with diesel engines and steam gas turbines as well as options for shaft or electric drive. The first commercial installation of the marine LM1600 gas turbine is in progress and sea trials will commence in late 1990.
This paper describes the design, performance, installation, and maintenance features of the marine LM1600 gas turbine.
Flowfield Calculation in Compressor Operating With Distorted Inlet Flow
Authors: Joubert H. 
Published: March 2015

In order to improve the air inlet engine compatibility, SNECMA has carried out since several years an important effort to predict the effect of distorted inlet flow on compressor stability.
Two different methods are developed:
In the first one, the Euler equations are integrated in 2D blade to blade surface with a distorted inlet flow. This method is used to compare different profiles, in particular influence of the chord length is presented.
In the second one, the aerodynamic behaviour of a multistage compressor operating in distorted inlet flow is calculated with a three dimensional method. This model is based on Euler equations resolution outside the rows.
An actuator disk model is used to represent the response of the blade rows.
The behaviour of a three stage axial compressor has been studied. The loss of surge margin and the pressure distortion transfer are compared with experimental data.
Experimental Investigation of the Stalled Flow in a Centrifugal Pump-Turbine With Varied Diffuser
Authors: Ubaldi Marina , Zunino Pietro 
Published: March 2015

Detailed measurements have been made of the stalled flow in a centrifugal pump-turbine model operating in air. Instantaneous velocity, total pressure and flow angle have been measured with hot wire and pressure probes at the impeller inlet and outlet and in the vaned diffuser for several pump operating points, ranging from nominal to very low flow rates.
Three distinct stall phenomena have been found to affect the pump operation at reduced flow rates. The unsteady characteristics of these unstable flows have been analysed both in time and in frequency domain by means of Fourier transforms of the velocity signals. The changes in the flow structure, correlated to the occurrence of the observed stall conditions, have been investigated by means of phase-locked ensemble averages of the instantaneous velocity components at the impeller outlet and surveys of the mean total pressure and absolute flow angle distributions within the diffuser passages.
Modification of a General Electric 7001B Turbine for Increased Reliability by Using 7001E Parts
Authors: Prugger David K. , McDermott William J. 
Published: March 2015

Parts of the latest design, incorporating improvements developed over 19 years of operating experience, can be utilized on the Model 7001B gas turbines.
This paper describes the initial application of the 7001E technology to an entire turbine retrofit. Component design improvements, interfaces, and limitations are described as well as expected reliability improvements.
Emphasis will be given to Field Service Engineering experience in installing this first change, since labor can be a significant part of the conversion.
Laser Two-Focus Anemometry Investigation of the Flow Field Within a Supersonic Axial Compressor Rotor
Authors: Trebinjac Isabelle , Vouillarmet André 
Published: March 2015

Laser anemometer measurements have been performed within and downstream of a supersonic single-stage high-pressure compressor. At design point and with standard upstream conditions the maximum relative Mach number varies from 1.3 at the tip to 1.1 at the hub. The stage total pressure ratio is 1.84 and the specific mass flow 180 kg/s/m2. The laser two-focus anemometer has been completely designed in the Laboratory; its originality being the use of a counting technique instead of the classical multichannel analyzer one. The data acquisition and reduction procedures are presented here.
A comprehensive evaluation of the global flow-field is in the scope of this paper. For that, the intra-blade flow field is described and the shock pattern is discussed. Furthermore, the experimental results are compared with both inviscid and viscous three-dimensional numerical simulations. The viscous computation is based on the Navier-Stokes solution using a mixing length turbulence model. The good agreement observed in this last case shows off the necessity of taking into account the viscous effects in a supersonic compressor flow calculation.
ATTAP/AGT101: Year 2 Progress in Ceramic Technology Development
Authors: Kidwell J. R. , Lindberg L. J. , Morey R. E. 
Published: March 2015

In the second year of a five-year Department of Energy (DOE) funded program, the Advanced Turbine Technology Applications Project (ATTAP) pushed ceramic automotive gas turbine technology state-of-the-art forward in:
• Ceramic materials assessment and characterization
• Ceramic impact damage assessment
• Ceramic combustor evaluation
• Turbine inlet particle separator development
• Impact-tolerant turbine designs
• Net-shape ceramic component fabrication
Materials characterization progressed from specimens to cut-up components. Impact damage threshold velocities were measured, using graphite projectiles against specimens and full-size rotors. Lean-burn ceramic combustor evaluations included ignition and carbon formation tests with DF-2, JP-4, and ethanol fuels. A third-generation ceramic turbine inlet particle separator demonstrated 97.5-percent effectiveness against rotor-damaging graphite particles. Improved ceramic component design capabilities are providing lower-stress components for incorporation into the critical hot flow path. Component fabrication development focussed on net-shape forming techniques, using Taguchi experiments.
ATTAP is funded by DOE and administered by NASA under Contract DEN3-335.
Dynamic Simulation of Compressor Station Operation Including Centrifugal Compressor and Gas Turbine
Authors: Botros K. K. , Campbell P. J. , Mah D. B. 
Published: March 2015

Dynamic simulation of the operation of a compressor station requires mathematical modelling of the dynamic behaviour of the compressor unit and various piping elements. Such models consist of large systems of non-linear partial differential equations describing the pipe flow together with non-linear algebraic equations describing the quasi-steady flow through various valves, constrictions and compressors. In addition, the models also include mathematical descriptions of the control system which consists of mixed algebraic and ordinary differential (mad) equations with some inequalities representing controllers’ limits.
In this paper a numerical technique for the solution of the gas dynamics equations is described, which is based on the transfer matrix formulation relating the state vector time-difference at one side of an element to that on the other side. This approach facilitates incorporation of all elements transfer matrices into an overall transfer matrix according to the system geometrical connectivity. The paper also presents simulation results and comparison with actual field measurements of three case histories: 1) simulation of a compressor surge protection control process; 2) unit startup; and 3) slow transient of a compressor station responding to changes in the discharge pressure set point. Good agreement between simulation results and field measurements is demonstrated.
The Aerodynamic and Mechanical Performance of a High Pressure Turbine Stage in a Transient Wind Tunnel
Authors: Sheard A. G. , Ainsworth R. W. 
Published: March 2015

A new transient facility for the study of time mean and unsteady aerodynamics and heat transfer in a high pressure turbine has been commissioned and results are available. A detailed study has been made of aspects of the performance and behaviour relevant to turbine mechanical design, and an understanding of the variation of the turbine operating point during the test, crucial to the process of valid data acquisition, has been obtained.
In this paper the outline concept and mode of operation of the tubine test facility are given, and the key aerodynamic and mechanical aspects of the facility’s performance are presented in detail. The variation of those parameters used to define the turbine operating point during facility operation are examined, and the accuracy with which the turbine’s design point was achieved calculated. Aspects of the mechanical performance which are presented include the results of a finite element stress analysis of the loads in the turbine under operating conditions, and the performance of the rotor bearing system under these arduous load conditions. Both of these aspects present more information than has been available hitherto.
Finally, the future work programme and possible plans for further facility improvement are given.
Three-Dimensional Flowfields Inside a Transonic Compressor With Swept Blades
Authors: Hah C. , Wennerstrom A. J. 
Published: March 2015

The concept of swept blades for a transonic or supersonic compressor was reconsidered by Wennerstrom in the early 1980s. Several transonic rotors designed with swept blades have shown very good aerodynamic efficiency. The improved performance of the rotor is believed to be due to reduced shock strength near the shroud and better distribution of secondary flows.
A three-dimensional flowfield inside a transonic rotor with swept blades is analyzed in detail experimentally and numerically. A Reynolds-averaged Navier-Stokes equation is solved for the flow inside the rotor. The numerical solution is based on a high-order upwinding relaxation scheme, and a two-equation turbulence model with a low Reynolds number modification is used for the turbulence modeling. To properly predict flows near the shroud, the tip-clearance flow also must be properly calculated. The numerical results at three different operating conditions agree well with the available experimental data and reveal various interesting aspects of shock structure inside the rotor.
Construction of a 700MW Combined Cycle Plant for YANAI Power Station No. 1
Authors: Shirakura S. , Ando N. , Hoshino K. 
Published: March 2015

The Chugoku Electric Power Co., Ltd. is currently constructing a 700MW combined cycle power plant at Yanai, Yamaguchi Prefecture, based on new design concepts.
This power plant consists of six single-shaft combined cycle units with construction in two phases.
Operation of the first phase, which includes three units with an output of 350 MW, will begin in November, 1990; operation of the second phase, which also includes three units with an output of 350 MW, will begin in December, 1992.
The notable features of this power plant are: High efficiency; short starting and stopping time; suitability for daily start/stop and large load variations; thorough NOx countermeasures; easy-to-use man-machine interface control systems; and short construction period based on improvement of construction methods.
The NOx countermeasures for the gas turbines are based on a newly-developed dry low NOx combustor which is designed so that the NOx emission level is 75 ppm or less for the entire load.
A functionally and hierarchically distributed digital control system has been used for the plant control system, so that the reliability, maintenability, and controllability will be improved.
In particular, an improvement was made to the man-machine interface. A CRT operation system and a large 110-inch screen are used together with an operation support system and a power plant office automation system.
Equipment installation is proceeding smoothly and field testing of the first units will begin in April, 1990.
Because this power plant is located in the Inland Sea National Park, thorough consideration has been taken in its appearance, such as color coordination, and landscaping of the power station area.
ACOUSTICAL STANDARDS NEWS
Authors: Blaeser Susan B. , Schomer Paul D. 
Published: March 2015

American National Standards (ANSI Standards) developed by Accredited Standards Committees S1, S2, S3, and S12 in the areas of acoustics, mechanical vibration and shock, bioacoustics, and noise, respectively, are published by the Acoustical Society of America (ASA). In addition to these standards, ASA publishes catalogs of Acoustical Standards, both National and International. To receive copies of the latest Standards catalogs, please contact Susan B. Blaeser.
Comments are welcomed on all material in Acoustical Standards News.
This Acoustical Standards News section in JASA, as well as the National and International Catalogs of Acoustical Standards, and other information on the Standards Program of the Acoustical Society of America, are available via the ASA Standards home page: http://acousticalsociety.org/standards.
Intercellular Diffusion of a Fluorescent Sucrose Analog via the Septal Junctions in a Filamentous Cyanobacterium
Authors: Nürnberg Dennis J. , Mariscal Vicente , Bornikoel Jan , Nieves-Morión Mercedes , Krauß Norbert , Herrero Antonia , Maldener Iris , Flores Enrique , Mullineaux Conrad W. 
Published: March 2015

ABSTRACT

Many filamentous cyanobacteria produce specialized nitrogen-fixing cells called heterocysts, which are located at semiregular intervals along the filament with about 10 to 20 photosynthetic vegetative cells in between. Nitrogen fixation in these complex multicellular bacteria depends on metabolite exchange between the two cell types, with the heterocysts supplying combined-nitrogen compounds but dependent on the vegetative cells for photosynthetically produced carbon compounds. Here, we used a fluorescent tracer to probe intercellular metabolite exchange in the filamentous heterocyst-forming cyanobacterium Anabaena sp. strain PCC 7120. We show that esculin, a fluorescent sucrose analog, is incorporated by a sucrose import system into the cytoplasm of Anabaena cells. The cytoplasmic esculin is rapidly and reversibly exchanged across vegetative-vegetative and vegetative-heterocyst cell junctions. Our measurements reveal the kinetics of esculin exchange and also show that intercellular metabolic communication is lost in a significant fraction of older heterocysts. SepJ, FraC, and FraD are proteins located at the intercellular septa and are suggested to form structures analogous to gap junctions. We show that a Δ
sepJ
Δ
fraC
Δ
fraD
triple mutant shows an altered septum structure with thinner septa but a denser peptidoglycan layer. Intercellular diffusion of esculin and fluorescein derivatives is impaired in this mutant, which also shows a greatly reduced frequency of nanopores in the intercellular septal cross walls. These findings suggest that FraC, FraD, and SepJ are important for the formation of junctional structures that constitute the major pathway for feeding heterocysts with sucrose.

IMPORTANCE
Anabaena and its relatives are filamentous cyanobacteria that exhibit a sophisticated form of prokaryotic multicellularity, with the formation of differentiated cell types, including normal photosynthetic cells and specialized nitrogen-fixing cells called heterocysts. The question of how heterocysts communicate and exchange metabolites with other cells in the filament is key to understanding this form of bacterial multicellularity. Here we provide the first information on the intercellular exchange of a physiologically important molecule, sucrose. We show that a fluorescent sucrose analog can be imported into the Anabaena cytoplasm by a sucrose import system. Once in the cytoplasm, it is rapidly and reversibly exchanged among all of the cells in the filament by diffusion across the septal junctions. Photosynthetically produced sucrose likely follows the same route from cytoplasm to cytoplasm. We identify some of the septal proteins involved in sucrose exchange, and our results indicate that these proteins form structures functionally analogous to metazoan gap junctions.
Cyclic GMP Balance Is Critical for Malaria Parasite Transmission from the Mosquito to the Mammalian Host
Authors: Lakshmanan Viswanathan , Fishbaugher Matthew E. , Morrison Bob , Baldwin Michael , Macarulay Michael , Vaughan Ashley M. , Mikolajczak Sebastian A. , Kappe Stefan H. I. 
Published: March 2015

ABSTRACT

Transmission of malaria occurs during Anopheles mosquito vector blood meals, when Plasmodium sporozoites that have invaded the mosquito salivary glands are delivered to the mammalian host. Sporozoites display a unique form of motility that is essential for their movement across cellular host barriers and invasion of hepatocytes. While the molecular machinery powering motility and invasion is increasingly well defined, the signaling events that control these essential parasite activities have not been clearly delineated. Here, we identify a phosphodiesterase (
PDE
γ) in Plasmodium, a regulator of signaling through cyclic nucleotide second messengers. Reverse transcriptase PCR (RT-PCR) analysis and epitope tagging of endogenous PDEγ detected its expression in blood stages and sporozoites of
Plasmodium yoelii
. Deletion of
PDE
γ (
pde
γ
−
) rendered sporozoites nonmotile, and they failed to invade the mosquito salivary glands. Consequently, PDEγ deletion completely blocked parasite transmission by mosquito bite. Strikingly,
pde
γ
−
sporozoites showed dramatically elevated levels of cyclic GMP (cGMP), indicating that a perturbation in cyclic nucleotide balance is involved in the observed phenotypic defects. Transcriptome sequencing (RNA-Seq) analysis of
pde
γ
−
sporozoites revealed reduced transcript abundance of genes that encode key components of the motility and invasion apparatus. Our data reveal a crucial role for
PDE
γ in maintaining the cyclic nucleotide balance in the malaria parasite sporozoite stage, which in turn is essential for parasite transmission from mosquito to mammal.

IMPORTANCE
Malaria is a formidable threat to human health worldwide, and there is an urgent need to identify novel drug targets for this parasitic disease. The parasite is transmitted by mosquito bite, inoculating the host with infectious sporozoite stages. We show that cellular signaling by cyclic nucleotides is critical for transmission of the parasite from the mosquito vector to the mammalian host. Parasite phosphodiesterase γ is essential for maintaining cyclic nucleotide balance, and its deletion blocks transmission of sporozoites. A deeper understanding of the signaling mechanisms involved in transmission might inform the discovery of novel drugs that interrupt this essential step in the parasite life cycle.