bluuebunny/crossref_metadata_2025_split huggingface dataset:
Operating Experience With Compressors of Large Heavy-Duty Gas Turbines
Authors: Becker B. , Bohn D. 
Published: April 2015

The shaft power of compressors in industrial-type gas turbines exceeds that which is attained by any other axial compressors. Their operating efficiency and availability are thus of prime importance expecially since gas turbines are being increasingly utilized for medium-range and base-load electric power generation. In addition to good aerodynamic design of the blading, correct dimensioning of the compressor blades to withstand the static and dynamic stresses that occur under various service conditions is a decisively important prerequisite for reliable operating performance. Measurement of the dynamic stresses is important for design verification and reliability confirmation.
Within the period between scheduled maintenance of a Model V 94 gas turbine, approx. 3,000 kg of solid particles flow through the compressor blading if the intake ambient air has a dust content of 0.1 mg/m3. The possible resulting erosion, corrosion and fowling negatively affect the long-term operating performance. The paper describes how these harmful effects can be effectively combatted by intake-air filtering, machine washing and blade coatings. The operating experience based on over one million service hours, of which more than one-third is with protected blades, demonstrates the success of the recommended compressor protection methods in achieving remarkably high operating availability.
A Method of Performance Evaluation and Equipment Selection for Combined Cycles Used in Cogeneration
Authors: Stephens James O. , Little D. A. 
Published: April 2015

The evaluation of the performance of a cogeneration cycle is a complex balance of heat assignments for various portions of the cycle. Selection of the optimum gas turbine, steam turbine, and boiler combination to match the process or district heating requirements requires numerous heat balances.
A method is presented to determine the most fuel-efficient cycle as well as the most efficient combination of equipment to meet the load profile. This system of plotting performance facilitates the selection of a combination that is the most economical for a given electrical and heat load requirement.
Parameters of boiler supplemental firing temperature and equivalent electrical heat rate with steam flow and total fuel consumption for all load conditions are displayed.
A New Generation T56 Turboprop Engine
Authors: McIntire W. L. 
Published: April 2015

The focus of the T56 Series IV turboprop engine development program is to improve power and fuel consumption through incorporation of demonstrated technology improvements while retaining the long term durability and cost effective design of the T56 family.
The T56-A-427, the Navy Series IV derivative of the 5000 shp (3728.5 kW) class T56 turboprop engine, resulted from over ten years of technology development via Advanced Turbine Engine Gas Generator (ATEGG), Joint Technology Demonstrator Engine (JTDE), and advanced component programs at Allison Gas Turbine Operations. An example of government and industry cooperation to transfer advanced gas turbine technology is the Air Force Engine Model Derivative Program (EMDP). The initial full-scale demonstration in this program confirmed a 10–1/2% reduction in specific fuel consumption (sfc) and a power growth of 21% in the basic T56 frame. Continued early demonstrations and development by IR&D, Navy funds, and Allison discretionary funds showed a further sfc reduction to 13% and power increase of 28%.
The full-scale development program is now underway to provide production engines in late 1986. Engines will be available for the Grumman E-2 and C-2 aircraft, with follow-on adaptions for Lockheed C-130/L100 and P-3 aircraft, and generator sets for DD 963, DDG 993, CG 47 and DDG 51 warships.
Size Effects in Small Radial Turbines
Authors: Scrimshaw K. H. , Williams T. J. 
Published: April 2015

The existence of size effects in small radial flow turbines, such as those used in automotive turbocharger units, has been investigated under steady flow conditions. Three geometrically similar turbines (rotor diameters 101.6, 67.73 and 50.8 mm respectively) have been tested and a ‘size’ effect was observed with the dimensionless mass flow and peak efficiency diminishing with a decrease in rotor diameter.
Internal pressure variations were observed in all three turbines which could have a significant influence in relation to blade fatigue failure.
Flow at the Tip of a Forward Curved Centrifugal Fan
Authors: Goulas A. , Mealing B. 
Published: April 2015

The velocity profiles, radial and circumferential components, were measured at the tip of a forward curved centrifugal fan. Three sets of measurements are presented. Two at peak efficiency for different rotational speeds and a third at the lower rotational speed and for a reduced flow rate.
A reverse flow region was formed near the hub, and almost in the middle, between pressure and suction sides of the blade. Near the shroud a high velocity region was observed and a low one near the suction side, picture similar to the jet-wake structure found in the literature.
At the lower rotational speed and low flow rate the flow was affected mainly by the system rotation. A “wake” was formed along the suction side of the blade. Increasing the flow rate blade curvature effects became more dominant.
Increasing the rotational speed and for the same flow coefficient the system of two vortices observed in the previous case disappears and a single vortex takes its place. In this case the wake is positioned on the hub.
Corner vortices also affect the main flow by changing the turbulence intensities. A corner vortex observed on the pressure side reduced the turbulence intensities in the region and a wake was formed locally. However, another corner vortex on the suction side caused an increase to the local turbulence intensities and consequently a high local velocity.
Turborotor Hybrid Gas Turbine Two-Phase Engine
Authors: Rashev Michael S. 
Published: April 2015

This paper analyzes the performance of an improved gas turbine engine, namely a turborotor hybrid gas turbine two-phase gas turbine engine (THGTE).
The central part of a conventional gas turbine engine is modified by introducing a number of turborotors comprising radially curved blades, to define together with the housing of the engine peripheral rotating interblade chamber-reservoirs and interblade radially curved energy-transfer passageways at their respective radially inward ends. The turborotors have the capability of energy exchange with the working fluid during the charging and expansion phases of engine operation, thus to provide a basic engine. During the expansion phase the turborotor performs a radial inflow impulse turbine function, and can be used to drive the engine’s compressor, thus to omit its conventional driving turbine.
The turborotor hybrid engine, formed by compounding the basic or turborotor engine with a conventional compressor and a power turbine has about 2 times lower specific weight and can be used as a jet propulsion turbineless engine, requiring only a nozzle to accelerate the gas products which exit the respective turborotors.
Due to its diesel mode of operation, the overall fuel efficiency is in the range of 0.58 without the use of a heat exchanger. Also, its specific power output is increased about 3 times, due to combustion of the entire amount of air passing through the compressor, under a higher fuel efficiency, if the hybrid engine is compared to the conventional gas turbine engine (CGTE).
A first approximation analysis is provided on the basis of the existing state-of-the-art and theory of the radial flow turbomachines to substantiate the basic advantages of the hybrid gas turbine engine.
Design and Part-Load Behavior of a Receiver for a Solar-Heated Gas Turbine With a Parabolic Dish Collector
Authors: Bammert Karl , Seifert Peter 
Published: April 2015

The present paper deals with the conversion of solar energy in a gas turbine plant with a parabolic dish collector. Particular consideration is devoted to the thermodynamic and mechanical design and partload behavior of the receiver. The incident sunlight is focussed by the parabolic dish and then beamed into the cavity receiver. Here the working medium of the gas turbine flows through tubes and is heated up to the receiver outlet temperature.
The task of the receiver is to transfer the radiated energy as efficiently as possible to the working medium. Furthermore the requiered heating surface should be small as possible i.e. optimum use must be made of the tube material with respect to its state of stress. It is shown which geometric and thermodynamic plant parameters influence these two design criteria. An optimum receiver design is presented on the basis of the results thus obtained. Finally, the variations in receiver efficiency and tube stressing when the gas turbine runs at constant speed or constant turbine inlet temperature, are investigated.
The Selection and Introduction of the MS9001E Gas Turbine
Authors: Brandt D. E. , Kelly A. G. 
Published: April 2015

This paper discusses the selection and integration of two 100 MW class uprated 50 Hz heavy duty gas turbines into an electric utility system which had significant prior experience with an earlier lower rated version. The new units have been installed in both simple and combined cycle application. Discussed are the various elements important to this selection including site considerations, economics, system requirements and prior gas turbine experience.
Although the uprated gas turbine model was evolved from a service-proven 60 Hz version the manufacturer implemented an extensive test program on one of the units to verify various design parameters and to confirm predicted performance. Stator parts and rotor components were fully instrumented in the simple cycle unit for these tests and results are discussed in this paper.
Presented are the extent of instrumentation and the test plan, the comparison of test data with analysis, the results of performance testing and the resulting modifications made to the Gas Turbine control system to enhance component life.
Current Status of Advanced Reheat Gas Turbine AGTJ-100A: Part 3 — Experimental Results of Shop Tests
Authors: Takeya Kazuo , Oteki Yasuo , Yasui Hajime 
Published: April 2015

The outline of plans for the research and development of an advanced reheat gas turbine under the Moonlight Project (Agency of Industrial Science and Technology, Ministry of International Trade and Industry) has already been announced in 1981 at Houston (81-GT-28), while technical problems related to the pilot plant (Paper No. 83-TOKYO-IGTC-117) as well as performance and characteristics (Paper No. 83-TOKYO-IGTC-40) have been announced at the 1983 Tokyo International Gas Turbine Congress.
No-load shop tests conducted on the pilot reheat gas turbine during the period of May to July, 1983, were consummated with highly satisfactory results, so this paper is dedicated primarily to giving a description of the shop tests.
Fiber Metal Abradable Seals
Authors: Tolokan R. P. , Beaton M. S. 
Published: April 2015

Fiber metal abradable seals are used to control clearances in the compressor and turbine sections of gas turbine engines. Fiber metal seals are good abradables that rub by the low energy mechanism of brittle fiber fracture over a wide range of rub conditions. Rub mechanisms are significantly influenced by features in the seal microstructure.
High temperature fiber metal seals have been developed with temperature capability to 1650°F (1170 K). These seals have been characterized to determine abradability, mechanical properties, temperature resistance and permeability.
Gasturbine for Pressurising a Fluidised Bed Combustion System
Authors: Dibelius G. H. , Croonenbrock R. , Pitt R. U. 
Published: April 2015

Pressurised fluidised bed combustion (PFBC) promises even lower emissions of air pollutant substances than already achieved by atmospheric FBC and allows to burn low rank coal. The elevated heat-transfer rate results in a more compact design.
A PFBC-fired steam generator for the heat and power plant of the Technical University of Aachen (RWTH) is under construction.
Being part of RWTH’s heat and power supply, a high reliability and a wide range of operation is mandatory. With these two aims in mind a scheme consisting of a turbo-charger’s compressor followed by an electrically driven compressor was chosen for the supply of air. The turbocharger’s turbine is fed by stack-gas previously cleaned by means of a pressure-tube-filter at moderate temperatures. Both machines are serial products.
While the turbocharger’s speed is determined by the operating conditions, the electrically driven compressor is controlled by adjustable inlet guide vanes. In the pressurised mode of operation, the load of the steam-generator can be varied between some 30 % and 100 % of maximum output.
The turbocharger may be bypassed to operate the system at atmospheric conditions. in this mode, 15 % to some 50 % of the operating range is covered.
Cooling Characteristics of Film-Cooled Turbine Blades
Authors: Abe T. , Doi N. , Kawaguchi T. , Yamane T. , Kumagai T. , Yoshida T. 
Published: April 2015

A series of experiments was performed to measure the cooling effectiveness of pin-fin type blades applicable to the first-stage blades of the high pressure turbine for the Advanced Gas Turbine of Japan (AGTJ-100A). Actual pin-fin type blades were used in three-dimensional hot cascade tests.
Resulting cooling effectiveness distributions in chordwise direction showed relatively small deviation from the high average value and closely corresponded with analytical predictions. Another major finding was that for film cooling blades, particularly with a shower head film cooling, it is essential in the cascade tests to set the ratio between the coolant and mainstream temperature at values the same as real conditions. This makes it possible to simulate cooling air flow distributions in the blades of high temperature actual turbines using low temperature tests. This is also applicable to vanes with a shower head film cooling.
In Nonobese Children, Fitness and BMI Are Independent Predictors of Fasting Insulin
Authors: Watson Andrew M. , Eickhoff Jens , Nemeth Blaise A. , Carrel Aaron L. 
Published: April 2015

Objective:Although fitness and obesity have been shown to be independent predictors of cardiometabolic disease risk in obese children, this interaction is not well defined in nonobese children. The purpose of this study was to define the relationships between peak aerobic capacity, body composition, and fasting insulin levels in nonobese middle school children.Study Design:148 middle school children (mean age 11.0 ± 2.1 years, 49% male) underwent determination of body mass index (BMI) z-score, fasting glucose, fasting insulin, body composition by DXA scan (lean body mass and body fat percentage), and peak oxygen uptake per kg of lean body mass (VO2peak). Univariate correlations and multivariate regression analysis were used to identify independent predictors of fasting insulin using age, sex, percent body fat, body mass index z-score, and VO2peak.Results:fasting insulin was significantly related to VO2peak (r =−0.37, p < .001), percent body fat (r = .27, p < .001), and BMI z-score (r = .33, p = .002). After inclusion in the multivariate model, VO2peak (p = .018) and body mass index z-score (p = .043) remained significant predictors of fasting insulin, while age (p = .39), sex (p = .49), and percent body fat (p = .72) did not.Conclusions:Among nonobese middle school children, fasting insulin is independently related to aerobic fitness after accounting for age, sex, and body composition. Public health efforts to reduce cardiometabolic disease risk among all adolescents should include exercise programs to increase cardiovascular fitness.
Cultures of Needleless Connectors Are Useful for Ruling Out Central Venous Catheter Colonization
Authors: Guembe María , Pérez-Granda María Jesús , Cruces Raquel , Martín-Rabadán Pablo , Bouza Emilio 
Published: April 2015

ABSTRACT
Semiquantitative cultures of skin surrounding intravascular catheter entry sites and catheter hubs have high negative predictive values for catheter tip colonization. However, culturing samples from the inner side of the hub requires the catheter to be manipulated, thus increasing the risk of migration of microorganisms into the bloodstream. Today, hubs are closed using needleless connectors (NCs). Cultures of NCs could predict catheter colonization. Our objective was to compare the yield of NC sonicate cultures for prediction of catheter colonization with that of hub cultures. For 6 months, we prospectively collected all short-term central lines and systems removed from patients admitted to the cardiac surgery postoperative care unit, irrespective of the reason for withdrawal. Hub cultures were obtained immediately before withdrawal and were cultured using a semiquantitative method. Catheter tips were cultured using the roll-plate technique and sonication, and NCs were cultured using a semiquantitative technique after sonication. We considered NCs to be colonized when ≥1 culture was positive. We collected a total of 75 central systems. The catheter colonization rate was 10.7%. The rates for hub and NC colonization were 6.7% and 12.0%, respectively. The validity values for hubs and NCs for prediction of catheter colonization were as follows: sensitivity, 25.0% and 87.5%; specificity, 95.5% and 97.0%; positive predictive value, 40.0% and 77.8%; negative predictive value, 91.4% and 98.5%; validity index, 88.0% and 96.0%, respectively. Cultures of closed NCs can be used to rule out catheter tip colonization and are superior to hub cultures in ruling out short-term central venous catheter colonization.
Functional Dynamics of the Gut Microbiome in Elderly People during Probiotic Consumption
Authors: Eloe-Fadrosh Emiley A. , Brady Arthur , Crabtree Jonathan , Drabek Elliott F. , Ma Bing , Mahurkar Anup , Ravel Jacques , Haverkamp Miriam , Fiorino Anne-Maria , Botelho Christine , Andreyeva Irina , Hibberd Patricia L. , Fraser Claire M. 
Published: April 2015

ABSTRACT

A mechanistic understanding of the purported health benefits conferred by consumption of probiotic bacteria has been limited by our knowledge of the resident gut microbiota and its interaction with the host. Here, we detail the impact of a single-organism probiotic,
Lactobacillus rhamnosus
GG ATCC 53103 (LGG), on the structure and functional dynamics (gene expression) of the gut microbiota in a study of 12 healthy individuals, 65 to 80 years old. The analysis revealed that while the overall community composition was stable as assessed by 16S rRNA profiling, the transcriptional response of the gut microbiota was modulated by probiotic treatment. Comparison of transcriptional profiles based on taxonomic composition yielded three distinct transcriptome groups that displayed considerable differences in functional dynamics. The transcriptional profile of LGG
in vivo
was remarkably concordant across study subjects despite the considerable interindividual nature of the gut microbiota. However, we identified genes involved in flagellar motility, chemotaxis, and adhesion from
Bifidobacterium
and the dominant butyrate producers Roseburia and Eubacterium whose expression was increased during probiotic consumption, suggesting that LGG may promote interactions between key constituents of the microbiota and the host epithelium. These results provide evidence for the discrete functional effects imparted by a specific single-organism probiotic and challenge the prevailing notion that probiotics substantially modify the resident microbiota within nondiseased individuals in an appreciable fashion.

IMPORTANCE
Probiotic bacteria have been used for over a century to promote digestive health. Many individuals report that probiotics alleviate a number of digestive issues, yet little evidence links how probiotic microbes influence human health. Here, we show how the resident microbes that inhabit the healthy human gut respond to a probiotic. The well-studied probiotic
Lactobacillus rhamnosus
GG ATCC 53103 (LGG) was administered in a clinical trial, and a suite of measurements of the resident microbes were taken to evaluate potential changes over the course of probiotic consumption. We found that LGG transiently enriches for functions to potentially promote anti-inflammatory pathways in the resident microbes.
Efficiency of Conditionally Attenuated Salmonella enterica Serovar Typhimurium in Bacterium-Mediated Tumor Therapy
Authors: Frahm Michael , Felgner Sebastian , Kocijancic Dino , Rohde Manfred , Hensel Michael , Curtiss Roy , Erhardt Marc , Weiss Siegfried 
Published: April 2015

ABSTRACT

Increasing numbers of cancer cases generate a great urge for new treatment options. Applying bacteria like
Salmonella enterica
serovar Typhimurium for cancer therapy represents an intensively explored option. These bacteria have been shown not only to colonize solid tumors but also to exhibit an intrinsic antitumor effect. In addition, they could serve as tumor-targeting vectors for therapeutic molecules. However, the pathogenic
S
. Typhimurium strains used for tumor therapy need to be attenuated for safe application. Here, lipopolysaccharide (LPS) deletion mutants (Δ
rfaL
, Δ
rfaG
, Δ
rfaH
, Δ
rfaD
, Δ
rfaP
, and Δ
msbB
mutants) of
Salmonella
were investigated for efficiency in tumor therapy. Of such variants, the Δ
rfaD
and Δ
rfaG
deep rough mutants exhibited the best tumor specificity and lowest pathogenicity. However, the intrinsic antitumor effect was found to be weak. To overcome this limitation, conditional attenuation was tested by complementing the mutants with an inducible arabinose promoter. The chromosomal integration of the respective LPS biosynthesis genes into the
araBAD
locus exhibited the best balance of attenuation and therapeutic benefit. Thus, the present study establishes a basis for the development of an applicably cancer therapeutic bacterium.

IMPORTANCE
Cancer has become the second most frequent cause of death in industrialized countries. This and the drawbacks of routine therapies generate an urgent need for novel treatment options. Applying appropriately modified
S
. Typhimurium for therapy represents the major challenge of bacterium-mediated tumor therapy. In the present study, we demonstrated that
Salmonella
bacteria conditionally modified in their LPS phenotype exhibit a safe tumor-targeting phenotype. Moreover, they could represent a suitable vehicle to shuttle therapeutic compounds directly into cancerous tissue without harming the host.