bluuebunny/crossref_metadata_2025_split huggingface dataset:
Relative contributions of emphysema and airway remodelling to airflow limitation in COPD: Consistent results from two cohorts
Authors: Tho Nguyen Van , Ryujin Yasushi , Ogawa Emiko , Trang Le Thi Huyen , Kanda Rie , Goto Kenichi , Yamaguchi Masafumi , Nagao Taishi , Lan Le Thi Tuyet , Nakano Yasutaka 
Published: March 2015

AbstractBackground and objectiveThe relative contributions of emphysema and airway remodelling to airflow limitation remain unclear in chronic obstructive pulmonary disease (COPD). We aimed to evaluate the relative contributions of emphysema and airway wall thickness measured by quantitative computed tomography (CT) to the prediction of airflow limitation in two separate COPD cohorts.MethodsPulmonary function tests and whole‐lung CT were performed in 250 male smokers with COPD, including 167 from University Medical Center at Ho Chi Minh City, Vietnam, and 83 from Shiga University of Medical Science Hospital, Japan. The same CT analysis software was used to measure the percentage of low attenuation volume (%LAV) at the threshold of −950 Hounsfield units and the square root of wall area of a hypothetical airway with an internal perimeter of 10 mm (Pi10). The standardized coefficients in multiple linear regressions were used to evaluate the relative contributions of %LAV and Pi10 to predictions of FEV1/FVC and FEV1% predicted.ResultsBoth %LAV and Pi10 independently predicted either forced expiratory volume in 1 s/forced vital capacity (FEV1/FVC) or FEV1% predicted (P ≤ 0.001 for all standardized coefficients). However, the absolute values of the standardized coefficients were 2−3 times higher for %LAV than for Pi10 in all prediction models. The results were consistent in the two COPD cohorts.Conclusions%LAV predicts both FEV1/FVC and FEV1 better than Pi10 in patients with COPD. Thus, emphysema may make a greater contribution to airflow limitation than airway remodelling in COPD.
Mechanical cues in orofacial tissue engineering and regenerative medicine
Authors: Brouwer Katrien M. , Lundvig Ditte M. S. , Middelkoop Esther , Wagener Frank A. D. T. G. , Von den Hoff Johannes W. 
Published: March 2015

ABSTRACTCleft lip and palate patients suffer from functional, aesthetical, and psychosocial problems due to suboptimal regeneration of skin, mucosa, and skeletal muscle after restorative cleft surgery. The field of tissue engineering and regenerative medicine (TE/RM) aims to restore the normal physiology of tissues and organs in conditions such as birth defects or after injury. A crucial factor in cell differentiation, tissue formation, and tissue function is mechanical strain. Regardless of this, mechanical cues are not yet widely used in TE/RM. The effects of mechanical stimulation on cells are not straight‐forward in vitro as cellular responses may differ with cell type and loading regime, complicating the translation to a therapeutic protocol. We here give an overview of the different types of mechanical strain that act on cells and tissues and discuss the effects on muscle, and skin and mucosa. We conclude that presently, sufficient knowledge is lacking to reproducibly implement external mechanical loading in TE/RM approaches. Mechanical cues can be applied in TE/RM by fine‐tuning the stiffness and architecture of the constructs to guide the differentiation of the seeded cells or the invading surrounding cells. This may already improve the treatment of orofacial clefts and other disorders affecting soft tissues.
Aerodynamic Research on Highload Axial Compressor With a Chordwise Split
Authors: Zhang Zhi-Gang , Shen Ping-Cheng , Zhu Hong , Lu Jia-Hua , Li Yan-Sheng 
Published: March 2015

This paper deals with a novel configuration of axial compressor cascade with chordwise split. Contrast to tandem cascade and cascade with a slot from pressure surface to suction surface, the cascade with a chordwise split not only controls the separation of boundary layer, increases flow turning angle and stage load, thus the compressor length can be shortened or pressure ratio increased, but also the flow pattern in the split is different.
The research work done shows that the cascade with chordwise split avoids or delays the separation of boundary layer on blade surface effectively thus may lead to a larger camber angle. The theoretical model and program for locating the split position and predicting flow field in cascade passage by using Finite Element Method are given.
Experiments have verified the mathematical model and the preferable effects of the chordwise split. The results of calculation correspond to the test data satisfactorily.
Development Test Status T-100 Multipurpose Small Power Unit
Authors: Napier James C. , Thompson Robert G. , Rodgers Colin 
Published: March 2015

An advanced technology small gas turbine program is being sponsored by the U.S. Army to complete the design, fabrication, and test of the T-100 Multipurpose Small Power Unit (MPSPU).
This paper describes the basic design features and current development status of the T-100. This small gas turbine power unit is designed for airborne, vehicular, and ground auxiliary power applications at low cost.
The T-100 design incorporates the most current aerothermodynamic and structural component technologies with extensive small turbomachinery and combustor experience gained from a similar class gas turbine two decades ago.
The T-100 design, fabrication, and component rig testing of the Inlet Protection System (IPS) compressor, combustor and turbine have been successfully completed. Engine testing is now in progress on the 50 HP (37.4 kw) rated unit.
Local-Global Analysis of Crack Growth in Continuously Reinforced Ceramic Matrix Composites
Authors: Ballarini Roberto , Ahmed Shamim 
Published: March 2015

This paper describes the development of a mathematical model for predicting the strength and micro-mechanical failure characteristics of continuously reinforced ceramic matrix composites. The local-global analysis models the vicinity of a propagating crack tip as a local heterogeneous region (LHR) consisting of spring-like representation of the matrix, fibers and interfaces. This region is embedded in an anisotropic continuum (representing the bulk composite) which is modeled by conventional finite elements.
Parametric studies are conducted to investigate the effects of LHR size, component properties, interface conditions, etc. on the strength and sequence of the failure processes in the unidirectional composite system. The results are compared with those predicted by the models developed by Marshall et al. (1985) and by Budiansky et al. (1986).
CAES Plant Performance and Economics as a Function of Underground Salt Dome Storage Transient Processes
Authors: Nakhamkin M. , Swensen E. , Schainker R. B. , Mehta B. 
Published: March 2015

This paper presents a discussion of the computer model developed to quantify the effects of transient processes occurring during injection, storage and withdrawal of compressed air from underground storage in a salt dome.
The following mechanisms are considered when modelling the thermodynamic behavior of the compressed air within the cavern:
1) Temperature variations due to the compression and expansion of the air.
2) Heat transfer by convection at the cavern wall.
3) Heat transfer by conduction inside the salt formation.
4) Enthalpy changes as air is injected into and withdrawn from the cavern.
The paper presents a description of the physical processes in the storage cavern, the calculation methodology, and results of the model as applied to the conditions of the storage cavern designed for the Alabama Electric Cooperative 100 MW CAES plant.
A Mini-Packaged Gas Turbine Cogeneration Unit
Authors: Babus’Haq Ramiz , O’Callaghan Paul , Probert Douglas 
Published: March 2015

The cogeneration process is the simultaneous production of electrical (or mechanical) power and heat, where the latter is a by-product of the power release process. In this investigation a mini-packaged gas turbine cogeneration unit is proposed for commercial and small industrial sectors. Its advantages are compared with those of a similar unit, but with a reciprocating engine as its prime mover.
While the basic concept of co-generation is quite simple and attractive, the analysis of its financial viability is complex. Thus a simple procedure has been devised to assess the economic viability of the proposed mini package. It has revealed that a pay-back period shorter than four years can be achieved by employing such a unit.
Application of Gas Turbines for Large Reciprocating Compressor Drive
Authors: Giacomelli E. , Bernardini F. , Pini A. , Andree H. 
Published: March 2015

The use of variable-speed drive systems such as gas turbines enhances the functional flexibility of reciprocating compressors.
This paper covers the main design aspects with correlation to direct experience of design, production, testing and operation on such units.
Thorough consideration has been given to a recent application onshore, where MS 1002 R (regenerative cycle) gas turbines, with 34% efficiency and 4620 kW ISO, drive a four-cylinder machine for natural gas storage in artificial caverns.
The selection criteria from the user’s point of view are analysed.
The theoretical and experimental results of torsional analysis, which represents one of the most important aspects for the complexity of the coupling of train components, are discussed.
The experience gained till now makes it possible to forecast an increasing application of gas turbine-compressor arrangements thanks to the energy-saving, advantages and the high reliability obtained with special design procedures design and modern full-load test facilities.
The Use of De-Swirl Nozzles to Reduce the Pressure Drop in a Rotating Cavity With a Radial Inflow
Authors: Farthing P. R. , Chew J. W. , Owen J. M. 
Published: March 2015

A combined theoretical and experimental study is described in which de-swirl nozzles were used to reduce the radial pressure drop in a rotating cavity with a radial inflow of air. The nozzles, which were attached to the outer part of the cavity, were angled such that the angular speed of the air at inlet could be in the opposite direction to that of the cavity. Solutions of the momentum-integral equations were used to predict the resulting radial distributions of pressure throughout the cavity.
Flow visualization was used to confirm the flow structure, and transducers attached to one of the rotating discs in the cavity were used to measure the radial pressure distributions. Results are presented for ‘swirl fractions’ (that is, the ratio of the angular speed of the air leaving the nozzles to that of the cavity) in the range −0.4 to + 0.9, and for 0.01 < | CW | Reϕ−0.8 < 0.5, where CW and Reϕ, are the nondimensional flow rate and rotational Reynolds number, respectively. The measured pressures are in good agreement with the predicted values, and the pressure drop across the cavity can be significantly less than that associated with solid-body rotation. The flow rate produced by the pressure drop across the cavity is not unique: there are up to three possible values of flow rate for any given value of pressure drop.
Reynolds Number Effects on the Performance of a Turbofan Engine
Authors: Kozu Masao , Yashima Satoshi 
Published: March 2015

Reynolds Number effects on the matching performance of a small twin-spool turbofan engine were investigated through the altitude tests of the F3-30 engine which was developed to power the Japan Air Self Defence Force’s T-4 intermediate trainer.
Analyzing the test results made it clear that the change of the aerodynamic characteristics of the low pressure turbine due to Reynolds Number effects is as significant as these of fan and compressor, and it caused the difference between the predicted and measured engine performance at high altitudes.
Correlation factors on the Reynolds Number for each of the component characteristics (pressure ratio, airflow and efficiency of fan and compressor, and gas flow and efficiency of low pressure turbine) were obtained, and simulation of the engine performance using these factors coincided well with the test data which were obtained from the altitude tests of the F3-30 at Arnold Engineering Development Center of U. S. Air Force.
Combustion Engineering at Laval University
Authors: Odgers J. , Kretschmer D. 
Published: March 2015

In 1966 Professor Dr. A. F. Schlader conceived the idea of introducing some form of research project on combustion engineering as an addition to the existing thermodynamics and heat transfer opportunities offered to graduate students. With help from the university and the National Research Council, he was able to establish a laboratory capable of testing a single combustion chamber (atmospheric inlet conditions) and another laboratory containing a small test rig for water flow visualisation. In 1968 the mechanical engineering department was augmented by the addition of a full-time professor to do research and teach combustion. For five years the teaching was limited to graduate courses, and at the same time, the laboratories were gradually being extended and improvements made, particularly with respect to instrumentation.
A major step was taken by the introduction of a course at the undergraduate level, and some five years after this, an additional undergraduate course was added as well as a complementary course on instrumentation. Laval University is one of few Canadian universities which offer a selection of undergraduate courses pertinent to combustion. All the undergraduate courses are ‘choice’, and the enrollment is generally from 10 to 35 students per course. On the retirement of Prof. Schlader a new professor was engaged. The expansion of the laboratories and their facilities continued to evolve such that they have become accepted as being of international stature. Initially almost all the work was concerned with gas turbine combustion, but of recent years several fundamental studies using laboratory flames have been carried out, and work has been done on automobile engine combustion and even some furnace work and the combustion of oil spills.
Flow Guiding and Distributing Devices on the Exhaust Side of Stationary Gas Turbines
Authors: Fleischer Friedrich , Koerner Christian , Mann Juergen 
Published: March 2015

Following repeated cases of damage caused to exhaust silencers located directly beyond gas turbine diffusers, this paper reports on investigations carried out to determine possible remedies.
In all instances, an uneven exhaust gas flow distribution was found to be present.
The company’s innovative approach to the problem involved constructing a scale model of a complete gas turbine exhaust system and using it for flow simulation purposes. It was established for the first time that, subject to certain conditions, the results of tests conducted on a model can be applied to the actual turbine exhaust system.
It is shown that when an unfavourable duct arrangement might produce an uneven exhaust flow, scale models are useful in the development of suitable flow-distributing devices.
Gas Turbine Operations of Synfuel Derived From Coal Gasification
Authors: Watts Donald H. , Gerstbrein Edward O. , Todd Douglas M. 
Published: March 2015

A modified version of a commercially available General Electric MS7001E gas turbine has been successfully operated on synfuel derived from coal at the Cool Water Coal Gasification Program.
This paper addresses Cool Water’s experience with the MS7001E gas turbine in base load applications; starting and operating reliability; maintenance experience; modifications to the gas turbine including fuel delivery, combustion and control systems; and, future applications of advanced gas turbines in Integrated Coal Gasification Combined Cycle (IGCC) service.
The Prediction of Boundary Layers With Rotation and Variation of Stream Filament Thickness
Authors: Yaonan Hua , Baoguo Wang 
Published: March 2015

The boundary layer equations with accounting for rotation and variation of stream filament thickness on the Sl stream surface of revolution in turbomachinery are derived in this paper. A method is presented for calculating laminar, turbulent and wake boundary layers by means of solving the integral momentum equation. The turbulent boundary layer with separation also can be calculated by use of present method.
The prediction of the boundary layer on the cascade blade of the DFVLR transonic axial compressor rotor was carried out in this paper. The effects of rotation and variation of stream filament thickness on the predicted behavior of the boundary layer are carefully investigated. It is shown that in certain cases their effects on the predicted results are significant.
Marine Gas Turbine Infra-Red Signature Suppression: Aerothermal Design Considerations
Authors: Birk A. M. , Vandam D. 
Published: March 2015

In recent years it has become evident that the Infrared (IR) Radiation given off by marine gas turbine exhaust systems is highly undesirable for naval vessels and commercial vessels traveling in areas of conflict. As a result, great interest has surfaced in the ways that IR signatures can be reduced. This paper presents an overview of some of the methods that can be used for engine exhaust IR signature suppression (IRSS). The methods considered here involve only ambient air addition for metal and plume cooling.
The present paper describes various IRSS systems and discusses the basic technical criteria for system selection. Basic operating principles are also described. Aerothermal design considerations are discussed and areas requiring special care during the design are highlighted. Because of the confidential nature of the subject, direct quantitative performance comparisons cannot be made.
The Design and Performance of a Reverse Flow Combustion System for the TP 500 Gas Turbine Engine
Authors: Carr E. , Todd H. 
Published: March 2015

The TP 500 is a 525 SHP turboprop engine being produced by Teledyne Continental Motors for general aviation use.
This paper describes the design and performance of the reverse flow fan spray combustion system being supplied for this engine. The main features of the design are described in some detail, together with the performance of the system as established in the combustion test facility at AIT Ltd and covering light-up to Take-Off conditions and sea level to 6km altitude.
Coal Generated Synthetic Gas Operating Experience With Two 100 MW-Class Combustion Turbines
Authors: Morrison E. M. , Pillsbury P. W. 
Published: March 2015

Dow Chemical, U. S. A., is currently operating two Westinghouse W501D5 combustion turbines with synthetic gas from the commercial demonstration coal gasification unit at Plaquemine, Louisiana.
The first of these units was fueled with synthetic gas in April 1987. This conversion followed several years of experimentation and prototype work by Dow and Westinghouse. The second unit began operating with synthetic gas during September 1987.
Addition of synthetic gas capability to these combustion turbines, originally installed in December 1982 and May 1983, was relatively straightforward, and once installed, did not adversely affect their operation or efficiency on natural gas, or mixtures in various proportions with synthetic gas. For durability assessment, special instrumentation was maintained at the site in the months immediately following conversion. This facilitated making minor changes to improve combustor longevity.
The heat recovery units were modified for synthetic gas operation to improve corrosion resistance and to handle higher temperatures. Minor adjustments were made in the controls to accommodate changing gas flow. Emission monitoring was enhanced.
A Prototype Replacement of a 100,000 Hours Operation, 25,000 KW Gas Turbine at Idemitsu Kosan Co., Ltd.
Authors: Furukawazono R. , Ishino H. , Kamata T. , Kunihiro M. , Kubota M. 
Published: March 2015

In September 1988, a Hitachi-GE model PG5341 gas turbine installed at the Tokuyama refinery of Idemitsu Kosan Co., Ltd. (Japan) successfully recorded 100,325 hours of base load operation over a period of 13 years with 99.4% reliability. The generated power totalled 1,341,770 MWh at the time of final shutdown.
The gas turbine, burning Bunker A oil, LPG, and heavy distillate oil, had been the main equipment in a cogeneration plant with a simple heat recovery steam generator using waste heat from the exhaust gas, plus a refired boiler.
It was expected that several costly hot gas path components of this turbine would have to be replaced in the near future, and it was not as fuel efficient as more modern designs, so it was decided to replace the PG5341 with a Hitachi H-25 gas turbine.
This new model H-25 is designed to have a rated output of 26,200kW and an efficiency of 32.3% (LHV) at the generator terminals under ISO conditions. By the use of a pressure ratio of 14.7 (up from 10.1) and a combustor outlet gas temperature of 1,260°C (up from 980°C), it is expected that efficiency of gas turbine will be improved relatively by 18.7% on a design basis, compared with the PG5341.
A factory full-load test of the prototype H-25 gas turbine was completed in August 1988 with excellent results. This machine has been in place and in operation at the Tokuyama plant since the end of November 1988. This is the first commercial application of the Hitachi H-25 advanced gas turbine.
Burner Rig Evaluation of Ceramic Coatings With Vanadium-Contaminated Fuels
Authors: Nagaraj B. A. , Wortman D. J. 
Published: March 2015

The performance of yttria stabilized zirconia (YSZ), ceria stabilized zirconia (CSZ), and magnesia stabilized zirconia (MSZ) coatings was evaluated using an atmospheric burner rig; the test environment contained compounds of vanadium, sodium and sulfur. The coatings were deposited by plasma spraying and electron beam physical vapor deposition (EB-PVD); sputtered sealant layers of hafnia, alumina and platinum were deposited on the yttria stabilized zirconia coating (YSZ). The tests were performed for up to 500 hours at 1650°F and 1300°F. The tests were designed to simulate the deposit chemistry and sulfur trioxide partial pressures expected in a marine gas turbine engine operating on contaminated fuel.
YSZ, CSZ, and MSZ coatings all underwent reaction in the burner rig environment; the reaction products and their effects on spallation were varied. MSZ was by far the most reactive, readily forming MgSO4 in both 1650°F and 1300°F tests. The observed reaction products provided a measure of “protection” for the bond coat by preventing molten salt infiltration in the duration of the test. The mechanism of ceramic spallation is discussed. Sputtered overlayers of platinum, hafnia and alumina did not prevent salt infiltration and reaction with the underlying ceramic, although no reaction product between the overlayer and the salt was observed.
Automated Welding of Turbine Blades
Authors: Liburdi J. , Lowden P. , Pilcher C. 
Published: March 2015

The welding of superalloys has been regarded, generally, as an art requiring the highest degree of welder skill and discipline. These highly alloyed materials are prone to micro-cracking and, in some cases, even the best welders cannot achieve satisfactory results.
Now, however, advances in automation technology have made it possible to program precisely the complex airfoil shapes and the welding parameters. Consequently, turbine blades can be welded in a repeatable manner, with a minimum of heat input resulting in better metallurgical quality both in the base metal and the weld deposit. The application of this technology to the automated welding of high-pressure compressor turbine blade tips, and the refurbishment of low-pressure turbine blade shrouds are presented in this paper.