bluuebunny/crossref_metadata_2025 huggingface dataset:
Depositional and Diagenetic Controls on Pore Structure of Tight Gas Sandstone Reservoirs: Evidence from Lower Cretaceous Bashijiqike Formation in Kelasu Thrust Belts, Kuqa Depression in Tarim Basin of West China
Authors: Lai Jin , Wang Guiwen , Chai Yu , Ran Ye , Zhang Xiaotao
Published: March 2015

Deeply buried Lower Cretaceous Bashijiqike sandstones are important gas exploration targets in the Kelasu thrust belt, Kuqa Depression of Tarim Basin in China. The sandstones are characterized by low porosity, low permeability and strong microscopic heterogeneity due to diagenesis during their geologic history. Mineralogical, petrographic, and geochemical analyses combined with high‐pressure mercury injection analysis have been used to investigate the diagenesis, diagenetic minerals, and their impact on reservoir quality. This article addresses the controls exerted by depositional parameters and diagenetic modifications on pore‐network characteristics (porosity, pore types, sizes, shapes, and distribution), with the aim to unravel the formation mechanisms of this complex pore structures, and to improve the characterization and classification evaluation for the Bashijiqike sandstone reservoirs. The Bashijiqike sandstones are dominated by lithic arkoses and feldspathic litharenite. The pore system consists of intergranular macropores, intergranular micropores, and intragranular pores. Framework grains are generally heavily compacted. Authigenic quartz, authigenic feldspar, clay minerals and carbonates are the major pore‐filling constituents. The pore structure is characterized by small pore radius and poor interconnectivity. Entry pressure reflects the microscopic pore network and macroscopic reservoir property characteristics. Pore structure characteristics are linked to the depositional parameters, type and degree of diagenesis. Clays do not control reservoir pore networks alone, and pores and pore throats are wider in coarser grained sandstones. Entry pressure decreases with the content of the rigid quartz. Compaction and cementation continue to decrease the pore‐throat size, while dissolution enlarges pores and pore‐throats radius. Considerable amounts of microporosity associated with clay minerals and altered grains contribute to the high entry pressure. Comprehensive Coefficient of Diagenesis (CCD), which considers the integrative effect of diagenesis, shows strong statistical correlations with entry pressure. CCD is an integrative modulus of diagenesis and physical property, and generally the higher the values are, the better the pore structure. It is suitable for quantitatively characterizing pore structure in tight gas sandstones. The results of this work can help assess pore‐network characteristics like the Bashijiqike sandstones which had experienced strong diagenetic modifications during their geological history.
Ar–Ar Ages of Hydrothermal Muscovite and Igneous Biotite at the Guposhan–Huashan District, Northeast Guangxi, South China: Implications for Mesozoic W–Sn Mineralization
Authors: Li Xiaofeng , Xiao Rong , Feng Zuohai , Chunxia Wei , Tang Yanwen , Bai Yanping , Zhang Mingji
Published: March 2015

The Guposhan–Huashan district is an important W–Sn–Sb–Zn–(Cu) metallogenic area in South China. It is located in the middle‐west segment of the Nanling Range. Granitoids in the Guposhan–Huashan district possess certain properties of A‐type or I‐type granites. The W–Sn–Sb–Zn mineralization in the district is closely associated with magma emplacement. Two igneous biotite and seven hydrothermal muscovite samples from skarn, veins and greisenization ores were analyzed by Ar–Ar methods. Two igneous biotite samples from fine‐grained quartz monzodiorite and fine‐grained biotite granite show plateau ages of 168.7 ± 1.9 Ma and 165.0 ± 1.1 Ma, respectively. Seven hydrothermal muscovite samples from ores yield plateau ages as two groups: 165 Ma to 160 Ma and 104 Ma to 100 Ma. These data suggest that the emplacement of fine‐grained granitoids in this district is coeval with the main phase magma emplacement, different from previous studies. The W–Sn–Sb–Zn mineralization took place in two stages, i.e. the Middle–Late Jurassic and early Cretaceous. W–Sn mineralization in the Guposhan–Huashan district is closely related to the magmatism, which was strongly influenced by underplating of asthenospheric mantle along trans‐lithospheric deep faults and related fractures.
Lithogeochemical, Re–Os and U–Pb Geochronological, Hf–Lu and S–Pb Isotope Data of the Ga'erqiong‐Galale Cu–Au Ore‐Concentrated Area: Evidence for the Late Cretaceous Magmatism and Metallogenic Event in the Bangong‐Nujiang Suture Zone, Northwestern Tibet, China
Authors: Zhang Zhi , Yao Xiao‐Feng , Tang Ju‐Xing , Li Zhi‐Jun , Wang Li‐Qiang , Yang Yi , Duan Ji‐Lin , Song Jun‐Long , Lin Xin
Published: March 2015

The Ga'erqiong‐Galale skarn–porphyry copper–gold ore‐concentrated area is located in the western part of the Bangong‐Nujiang suture zone north of the Lhasa Terrane. This paper conducted a systematic study on the magmatism and metallogenic effect in the ore‐concentrated area using techniques of isotopic geochronology, isotopic geochemistry and lithogeochemistry. According to the results, the crystallization age of quartz diorite (ore‐forming mother rock) in the Ga'erqiong deposit is 87.1 ± 0.4 Ma, which is later than the age of granodiorite (ore‐forming mother rock) in the Galale deposit (88.1 ± 1.0 Ma). The crystallization age of granite porphyry (GE granite porphyry) in the Ga'erqiong deposit is 83.2 ± 0.7 Ma, which is later than the age of granite porphyry (GL granite porphyry) in the Galale deposit (84.7 ± 0.8 Ma).The quartz diorite, granodiorite, GE granite porphyry and GL granite porphyry both main shows positive εHf(t) values, suggesting that the magmatic source of the main intrusions in the ore‐concentrated area has the characteristics of mantle source region. The Re–Os isochron age of molybdenite in the Ga'erqiong district is 86.9 ± 0.5 Ma, which is later than the mineralization age of the Galale district (88.6 ± 0.6 Ma). The main intrusive rocks in the ore‐concentrated area have similar lithogeochemical characteristics, for they both show the relative enrichment in large‐ion lithophile elements(LILE: Rb, Ba, K, etc.), more mobile highly incompatible lithophile elements(HILE: U, Th) and relatively depleted in high field strength elements (HFSE: Nb, Ta, Zr, Hf, etc.), and show the characteristics of magmatic arc. The studies on the metal sulfides' S and Pb isotopes and Re content of molybdenite indicate that the metallogenic materials of the deposits in the ore‐concentrated area mainly come from the mantle source with minor crustal source contamination. Based on the regional tectonic evolution process, this paper points out that the Ga'erqiong‐Galale copper–gold ore‐concentrated area is the typical product of the Late Cretaceous magmatism and metallogenic event in the collision stage of the Bangong‐Nujiang suture zone.
Ore Genesis and Formation Age of the Gaogangshan Mo Deposit, Heilongjiang Province, NE China
Authors: Hao Yu‐Jie , Ren Yun‐Sheng , Yang Qun , Duan Ming‐Xin , Sun Qi , Fu Li‐Chun , Li Chao
Published: March 2015

The Gaogangshan Mo deposit, located in the northern part of the Lesser Xing'an Range (the eastern part of the Xing'an–Mongolia Orogenic Belt), is one of the newly discovered Mo deposits in northeast China. Ore bodies occur in the granite and are generally in vein and stockwork forms. Major metallic minerals in the ore include pyrite and molybdenite. The styles of mineralization are disseminated, veinlet–disseminated, and veinlet. The major types of wall–rock alteration are silicification–potassic alteration, phyllic alteration and propylitization. Fluid inclusion analyses indicate that the ore‐forming fluid during the major mineralization stage is an H2O–NaCl–CO2 system, with wide homogenization temperature and salinity ranges. The abundant CO2–rich and coexisting halite–bearing fluid inclusion assemblages in the main stage of mineralization highlight the significance of intensive fluid boiling for porphyry Mo mineralization. Comprehensive study of the ore‐forming conditions, geological features of the deposit, micro‐thermometric analysis of fluid inclusions and comparison of the Gaogangshan deposit with other typical porphyry deposits leads to the conclusion that the deposit is a porphyry type. We obtained a weighted mean age of the molybdenite deposit at Gaogangshan of 250.7 ± 1.8 Ma. The isotopic dating results indicate that the Gaogangshan deposit was formed in the Permo–Triassic, which is the earliest Mo–only deposit in northeast China. The formation of the Gaogangshan Mo deposit may be related to the extension and break–up of the Songnen Block and Jiamusi Block in the Permo–Triassic.
Complex Numeral Expressions: A Plea for Grafts
Authors: Meinunger André
Published: March 2015

Grafting is a syntactic device developed and defended by van Riemsdijk (2000 and subsequent work) by which two independent input trees are connected via external remerger of internal elements, thus sharing a constituent. Grafting clearly violates standard assumptions about phrase structure. Still, several structures found in natural language are best analyzed in terms of grafting. The present paper discusses one such construction: complex numerals. It shows that the characteristic multidominance of grafting explains the word order, case assignment, plural, paucal, and singular distribution associated with complex numeral combinations better than a coordination approach and is more compatible with more number (or counting) systems found in the world's languages.
The Algorithmic Level Is the Bridge Between Computation and Brain
Authors: Love Bradley C.
Published: March 2015

Every scientist chooses a preferred level of analysis and this choice shapes the research program, even determining what counts as evidence. This contribution revisits Marr's (1982) three levels of analysis (implementation, algorithmic, and computational) and evaluates the prospect of making progress at each individual level. After reviewing limitations of theorizing within a level, two strategies for integration across levels are considered. One is top–down in that it attempts to build a bridge from the computational to algorithmic level. Limitations of this approach include insufficient theoretical constraint at the computation level to provide a foundation for integration, and that people are suboptimal for reasons other than capacity limitations. Instead, an inside‐out approach is forwarded in which all three levels of analysis are integrated via the algorithmic level. This approach maximally leverages mutual data constraints at all levels. For example, algorithmic models can be used to interpret brain imaging data, and brain imaging data can be used to select among competing models. Examples of this approach to integration are provided. This merging of levels raises questions about the relevance of Marr's tripartite view.
A Cell‐Based Assay Reveals Nuclear Translocation of Intracellular Domains Released by SPPL Proteases
Authors: Mentrup Torben , Häsler Robert , Fluhrer Regina , Saftig Paul , Schröder Bernd
Published: March 2015

During regulated intramembrane proteolysis (RIP) a membrane‐spanning substrate protein is cleaved by an ectodomain sheddase and an intramembrane cleaving protease. A cytoplasmic intracellular domain (ICD) is liberated, which can migrate to the nucleus thereby influencing transcriptional regulation. Signal peptide peptidase‐like (SPPL) 2a and 2b have been implicated in RIP of type II transmembrane proteins. Even though SPPL2a might represent a potential pharmacological target for treatment of B‐cell‐mediated autoimmunity, no specific and potent inhibitors for this enzyme are currently available. We report here on the first quantitative cell‐based assay for measurement of SPPL2a/b activity. Demonstrating the failure of standard Gal4/VP16 reporter assays for SPPL2a/b analysis, we have devised a novel system employing β‐galactosidase (βGal) complementation. This is based on detecting nuclear translocation of the proteolytically released substrate ICDs, which results in specific restoration of βGal activity. Utilizing this potentially high‐throughput compatible new setup, we demonstrate nuclear translocation of the ICDs from integral membrane protein 2B (ITM2B), tumor necrosis factor (TNF) and CD74 and identify secreted frizzled‐related protein 2 (SFRP2) as potential transcriptional downstream target of the CD74 ICD. We show that the presented assay is easily adaptable to other intramembrane proteases and therefore represents a valuable tool for the functional analysis and development of new inhibitors of this class of enzymes.
Plasma exchange effectively removes 52‐ and 60‐kDa anti‐Ro/SSA and anti‐La/SSB antibodies in pregnant women with congenital heart block
Authors: Tonello Marta , Ruffatti Amelia , Marson Piero , Tison Tiziana , Marozio Luca , Hoxha Ariela , De Silvestro Giustina , Punzi Leonardo
Published: March 2015

BACKGROUND

Pregnant women positive for 52‐ and 60‐kDa anti‐Ro/SSA and anti‐La/SSB antibodies can suffer from congenital heart block (CHB), a passively acquired autoimmune disease.

STUDY DESIGN AND METHODS

We evaluated the efficacy of plasma exchange (PE) in removing 52‐ and 60‐kDa anti‐Ro/SSA and anti‐La/SSB antibodies in pregnant women with CHB treated with a combined therapy including PE, intravenous immunoglobulins, and steroids. Antibody levels were monitored in 10 consecutive pregnant women diagnosed with CHB and prospectively followed between 2009 and 2013. Assaying was performed using a homemade enzyme‐linked immunosorbent assay test on blood samples collected immediately before and after PE sessions.

RESULTS

A significant decrease in mean post‐PE antibody levels was noted in all the cases examined. An analysis of antibody level trends in the samples collected before PE sessions showed that there was a steady, significant decrease in 90% of the patients with 52‐kDa anti‐Ro/SSA, in 80% of those with 60‐kDa anti‐Ro/SSA antibodies, and in 100% of those with anti‐La/SSB antibodies.

CONCLUSION

This study demonstrates that PE is effective in removing antibodies linked to the pathogenesis of CHB. PE treatment was found to have a long‐term efficacy in all the women positive for anti‐La/SSB antibodies and in most of the women positive for 52‐ and 60‐kDa anti‐Ro/SSA antibodies. It is interesting that the significant, immediate, and long‐term fall in antibody levels that was observed in these patients took place in all the women whose CHB was reversed. This finding could give PE an important role in the treatment of CHB.
Making thawed universal donor plasma available rapidly for massively bleeding trauma patients: experience from the Pragmatic, Randomized Optimal Platelets and Plasma Ratios (PROPPR) trial
Authors: Novak Deborah J. , Bai Yu , Cooke Rhonda K. , Marques Marisa B. , Fontaine Magali J. , Gottschall Jerome L. , Carey Patricia M. , Scanlan Richard M. , Fiebig Eberhard W. , Shulman Ira A. , Nelson Janice M. , Flax Sherri , Duncan Veda , Daniel‐Johnson Jennifer A. , Callum Jeannie L. , Holcomb John B. , Fox Erin E. , Baraniuk Sarah , Tilley Barbara C. , Schreiber Martin A. , Inaba Kenji , Rizoli Sandro , Podbielski Jeanette M. , Cotton Bryan A. , Hess John R. ,   on behalf of the PROPPR Study Group
Published: March 2015

BACKGROUND

The Pragmatic, Randomized Optimal Platelets and Plasma Ratios (PROPPR) trial was a randomized clinical trial comparing survival after transfusion of two different blood component ratios for emergency resuscitation of traumatic massive hemorrhage. Transfusion services supporting the study were expected to provide thawed plasma, platelets, and red blood cells within 10 minutes of request.

STUDY DESIGN AND METHODS

At the 12 Level 1 trauma centers participating in PROPPR, blood components transfused and delivery times were tabulated, with a focus on universal donor (UD) plasma management. The adequacy of site plans was assessed by comparing the bedside blood availability times to study goals and the new American College of Surgeons guidelines.

RESULTS

Eleven of 12 sites were able to consistently deliver 6 units of thawed UD plasma to their trauma‐receiving unit within 10 minutes and 12 units in 20 minutes. Three sites used blood group A plasma instead of AB for massive transfusion without complications. Approximately 4700 units of plasma were given to the 680 patients enrolled in the trial. No site experienced shortages of AB plasma that limited enrollment. Two of 12 sites reported wastage of thawed AB plasma approaching 25% of AB plasma prepared.

CONCLUSION

Delivering UD plasma to massively hemorrhaging patients was accomplished consistently and rapidly and without excessive wastage in high‐volume trauma centers. The American College of Surgeons Trauma Quality Improvement Program guidelines for massive transfusion protocol UD plasma availability are practicable in large academic trauma centers. Use of group A plasma in trauma resuscitation needs further study.
Propensity of red blood cells to undergo P2X7 receptor–mediated phosphatidylserine exposure does not alter during in vivo or ex vivo aging
Authors: Sophocleous Reece A. , Mullany Phillip R.F. , Winter Kelly M. , Marks Denese C. , Sluyter Ronald
Published: March 2015

BACKGROUND

Phosphatidylserine (PS) exposure facilitates the removal of red blood cells (RBCs) from the circulation, potentially contributing to the loss of stored RBCs after transfusion, as well as senescent RBCs. Activation of the P2X7 receptor by extracellular adenosine 5′‐triphosphate (ATP) can induce PS exposure on freshly isolated human RBCs, but whether this process occurs in stored RBCs or changes during RBC aging is unknown.

STUDY DESIGN AND METHODS

RBCs were processed and stored according to Australian blood banking guidelines. PS exposure was determined by annexin V binding and flow cytometry. Efficacy of P2X antagonists was assessed by flow cytometric measurements of ATP‐induced ethidium+ uptake in RPMI 8226 cells. Osmotic fragility was assessed by lysis in hypotonic saline. RBCs were fractionated by discontinuous density centrifugation.

RESULTS

ATP (1 mmol/L) induced PS exposure on RBCs stored for less than 1 week. This process was near‐completely inhibited by the P2X7 antagonists A438079 and AZ10606120 and the P2X1/P2X7 antagonist MRS2159 but not the P2X1 antagonist NF499. ATP‐induced PS exposure on RBCs was not dependent on K+, Na+, or Cl− fluxes. ATP did not alter the osmotic fragility of stored RBCs. ATP‐induced PS exposure was similar between RBCs of different densities. ATP‐induced PS exposure was also similar between RBCs stored for less than 1 week or for 6 weeks.

CONCLUSION

The propensity of RBCs to undergo P2X7‐mediated PS exposure does not alter during in vivo and ex vivo aging. Thus, P2X7 activation is unlikely to be involved in the removal of senescent RBCs or stored RBCs after transfusion.
Preliminary Tests of Catalytic Combustion in a Small Gas Turbine
Authors: Hoshino A. , Kajita S. , Hagiwara Y. , Fujimoto K. , Kitajima J.
Published: March 2015

A catalytic combustor and its control system have been developed and tested on a 150 kW small gas turbine engine. The fuel for the tests was gaseous fuel which consists of 92% CH4 and 8% C3H8. The emission characteristics in the catalytic operating mode and the control procedure during transient operation were investigated in the tests. Results indicated extremely low NOx emissions. However, it was also apparent that further development tests are required to improve combusion efficiency, durability of catalysts, and control stability during transient operation.
Flexibility of the Closed Brayton Cycle for Space Power
Authors: Davis Keith A.
Published: March 2015

New commercial and military applications for space power are developing over a wide range of nominal and peaking power requirements. Power levels far exceed the capabilities of photovoltaic array and battery systems. Factors such as manned and unmanned missions, long mission durations, zero-maintenance requirements, hardening from attack, and mission orbit or mission payload impact space power system specifications and dictate the type of energy source. This has led to emphasis on the closed Brayton cycle (CBC) with its inherent flexibility as a dynamic power source.

Unique features of the CBC contribute to its application to the multiplicity of space power requirements. These include flexibility of design, operation, energy source selection, and future growth.

The CBC with the single-phase, gas working fluid provides a simple interface for chemical, isotope, solar, and nuclear thermal energy sources. The single-phase gas is not affected by zero gravity, freezing or high temperatures, vehicle launch, or flight maneuver loads. This feature is a primary contributor to the CBC flexibility.
A Qualitative Method for Determining the Temperature Pattern of Run Gas Turbine Blades
Authors: McQuiggan G. , Linkert W.
Published: March 2015

The temperature of gas turbine blades is a critical parameter in determining the expected life of the blades.
Fire Detection and Suppression in Natural Gas Pipeline Compressor Stations
Authors: Meyer Colton W.
Published: March 2015

The occurrence of fires in natural gas compressor stations is fortunately infrequent. The consequences, however, can be severe. This paper will discuss the design concepts and experience of Pacific Gas Transmission Company (PGT) with fire detection and suppression systems in its natural gas pipeline compressor stations.
Blade Excitation Criteria Developed for Aero Derived Engines in Arctic Alaska
Authors: Clough H. J.
Published: March 2015

Aero derived gas turbines are now used for land based power generation throughout the world. Virtually all of these engine types stem from proven designs that have achieved many thousands of hours of reliable operation in the demanding aircraft environment.
Observations on the Life and Overhaul Requirements of Aero Derivative Engines on Base Load Industrial Applications
Authors: Lowden P. , Liburdi J.
Published: March 2015

Experience in examining the overhauls on industrial aero-derivative engines has shown that the usual flight standards and procedures are not always applicable to ensure prolonged service under base load applications. Not only are changes often required in recommended overhaul intervals, but the methods used to analyze remaining life, and the repair procedures employed to refurbish turbine blades must be re-examined to allow for long term creep and aging phenomena. To illustrate the potential problems encountered, examples from various engines are presented and the changes in overhaul philosophy required to cope with the base load applications are outlined.
Current Gas Turbine Combustion and Fuels Research and Development
Authors: Peters J. E.
Published: March 2015

This paper is a review of current research and development work in gas turbine combustion and fuels based on publications in the open literature and papers and reports supplied to the author by various gas turbine manufacturers on their current combustor research and development programs. Both aircraft and industrial applications are considered for the two major topics that are covered in the paper, alternative fuels and computer modeling, and for the illustration of two combustor component research and development activities. For aircraft applications, alternative fuel studies have centered on “heavier” fuels and have shown physical properties of the fuels which influence atomization and vaporization to be of primary concern regarding ignition and flame stability while chemical properties are more important to particulate emissions, heat transfer and liner durability considerations. For industrial applications, the use of medium to low heating value fuels and coal slurries have received much attention with particular emphasis on fuel delivery and mixing modifications within the combustor to accommodate these fuels. Computer modeling continues to play an increasingly important role in combustor development; currently the so-called “TEACH” based codes and their offspring are used for the majority of the computational fluid dynamics applications for gas turbine combustors. However, much work is being directed towards advanced differencing schemes, complex boundary fitting programs and proper treatment of inlet and boundary conditions in addition to studies devoted to advancing the physical submodels that are incorporated in the codes. Finally, two examples of research and development for specific design considerations are illustrated with a discussion of recent efforts on staged combustion for NOx control and on fuel injection.
Thermodynamics and Performance Projections for Intercooled/Reheat/Recuperated Gas Turbine Systems
Authors: El-Masri Maher A.
Published: March 2015

Intercooled/Recuperated gas turbine systems provide high-efficiency and power density for naval propulsion. Current aero-derivative systems are capable of about 43% thermal efficiency in this configuration. With continued progress in gas-turbine materials and cooling technology, the possibility of further improving system performance by incorporation of gas-turbine reheat arises. A preliminary scan of this class of cycles is presented and compared with non-reheat intercooled/recuperated cycles at two levels of component technology. For conservative component technology, the reheat is found to provide very modest performance advantages. With advanced components and ceramic thermal barrier coatings, the reheat is found to offer potential for specific power improvements of up to 33% and for modest efficiency gains, on the order of one percentage point, while enabling turbine inlet temperatures well below those for the most efficient non-reheat cycles. The high-performance reheat systems, however, require reheat-combustor inlet temperatures beyond current practice.

The use of water-injection in the intercooler, together with an aftercooler and a water-injected evaporative-recuperator is found to produce very large gains in efficiency as well as specific power. This modification may be feasible for land-based systems, where it can compete favourably with combined cycles. Despite the difficulty of obtaining pure water for a shipboard propulsion system, those large gains may justify further studies of this system and of means to provide its water supply in marine applications.
A Low NOx Combustion System and a Ceramic Cross Flow Heat Exchanger for Small Gas Turbines
Authors: Förster Siegfried , Quell Peter
Published: March 2015

A new low NOx oil-combustion system with superheated steam fuel evaporation prior to combustion has been found especially feasible for open cycle gas turbines with high turbine inlet temperatures and ceramic cross flow heat exchanger.

The actual state of development of both the low NOx light fuel-oil combustion system and ceramic heat exchanger elements, especially the cross flow type, is outlined in this paper. The use of this combustion system results in considerably lower combustion temperatures in the primary combustion zone, reducing the NOx-production even at high air temperatures when the air is preheated in the heat exchanger. The water vapour used for the evaporation of the fuel oil before combustion has an improving effect on the cycle efficiency comparable to the Cheng-dual-fluid-cycle. Illustrative evaluations for a gas turbine cycle for a shaft power of 70 kW are given.
Analytical and Experimental Investigation of the Stability of the Rotor-Bearing System of a New Small Turbocharger
Authors: Born H. R.
Published: March 2015

This paper presents an overview of the development of a reliable bearing system for a new line of small turbochargers where the bearing system has to be compatible with a new compressor and turbine design.

The first part demonstrates how the increased weight of the turbine, due to a 40 % increase in flow capacity, influences the dynamic stability of the rotor-bearing system.

The second part shows how stability can be improved by optimizing important floating ring parameters and by applying different bearing designs, such as profiled bore bearings supported on squeeze film dampers.

Test results and stability analyses are included as well as the criteria which led to the decision to choose a squeeze film backed symmetrical 3-lobe bearing for this new turbocharger design.
An Experimental Investigation Into the Influence of Diameter-Blade Height Ratios on Secondary Flow Losses in Annular Cascades With Leaned Blades
Authors: Zhong-Qi Wang , Wan-Jin Han , Wen-Yuan Xu
Published: March 2015

Three groups of the annular turbine cascades with diameter-blade height ratios d/1 = 1.9, 3, and 5 respectively are tested. Each group includes five types of cascades equipped with different kinds of leaned blades. For each type of the cascades, the distributions of total pressure, static pressure and exit flow angle along the pitch and the blade height are surveyed in detail. The experimental results show that the smaller the diameter-blade height ratio of the cascade, the more effective application of positively leaned blade to reduce the secondary flow loss, when the inner and outer walls of the cascade are cylindrical. Under this condition the effect of the blade leaning on the energy loss distribution along the blade height is notable. There is an optimal lean angle corresponding to the minimum of the overall energy loss in each cascade with leaned blades. The function-relation between the optimal lean angle and the diameter-blade height ratio is monotonic.
A Solution of the Interaction Between an Inviscid Flow Along S1 Stream Surface and a Boundary Layer With Separation Bubbles
Authors: Shun Kang , Zhongqi Wang
Published: March 2015

By use of a streamline coordinate system, the general expressions of a momemtum integral equation, an entraiment equation and an equivalent source strength of S1 stream surface have been established in this paper. The method for solving S1 stream surface boundary layer with separation bubbles has been proposed with the iteration of an inverse method for solving boundary layer integral equation and the Veldman model of inviscid-viscous interaction. Prediction results of some examples given in this paper have shown that they are in good agreement with experimental ones.
Applications for Hydrocarbon Testing in Centrifugal Compressors
Authors: Hughes G. A.
Published: March 2015

The goal of any test must be to prove reliability. In centrifugal compressers there are basically two types of tests. The first proves the mechanical integrity, while the second verifies the aerodynamic performance. No one test can satisfy all goals so it is left to the purchaser to specify the type of test(s) which will satisfy his requirements. This paper discusses the limitations of various types of tests. Emphasis is given to Hydrocarbon Testing and, in particular, Class I Hydrocarbon Testing.
Effects of Injection on Condensation on a Film-Cooled Surface
Authors: Webster William Phil , Yavuzkurt Savash
Published: March 2015

Gas turbine blades have previously been shown to corrode due to condensation of sulfide vapor on a cooled blade surface. In the present investigation, water vapor was condensed on a film cooled surface, simulating the condensation of sulfide vapor on a turbine blade. The injection section consisted of one row of holes (inner diameter of 1.0 cm) inclined 30 degrees with the surface and inline with the main turbulent boundary layer flow. Experiments were carried out in a subsonic, zero pressure gradient, turbulent boundary layer with free stream velocities of 10.5, 15.75, and 21.0 m/sec. A cooling fluid (water at near 0°C) was circulated through the plate, cooling the test surface and causing free stream water vapor to condense. Measurements were made at three Reynolds numbers (based on hole diameter and free stream velocity): 7,000, 10,500, and 14,000; and at three blowing ratios: 0.4, 0.8, 1.2. The results show the existence of a “dryout” region downstream of each cooling hole. This region was dry while regions between the jets had water on the surface. This dryout region was triangularly shaped, with the apex as much as 30 jet diameters from the downstream edge of the jet. For each Reynolds number the lowest blowing ratio (M = 0.4) had the largest dryout region. These results indicate that injection can be used to prevent condensation of corrosive vapors on a film-cooled gas turbine blade.
Helium Circulator Design Considerations for Modular High Temperature Gas-Cooled Reactor Plant
Authors: McDonald Colin F. , Nichols Michael K.
Published: March 2015

Efforts are in progress to develop a standard modular high temperature gas-cooled reactor (MHTGR) plant that is amenable to design certification and serial production. The MHTGR reference design, based on a steam cycle power conversion system, utilizes a 350 MW(t) annular reactor core with prismatic fuel elements. Flexibility in power rating is afforded by utilizing a multiplicity of the standard module. The circulator, which is an electric motor-driven helium compressor, is a key component in the primary system of the nuclear plant, since it facilitates thermal energy transfer from the reactor core to the steam generator; and, hence, to the external turbo-generator set. This paper highlights the helium circulator design considerations for the reference MHTGR plant and includes a discussion on the major features of the turbomachine concept, operational characteristics, and the technology base that exists in the U.S.
Aspects of the Design of Swirlers as Used in Fuel Injectors for Gas Turbine Combustors
Authors: Martin C. A.
Published: March 2015

An attempt is made to review the state of the art, in swirler design and performance, as it applies to airblast atomizers. The purpose of this review is to summarize existing information on swirler design aspects and performance, as well as to clarify and initiate the standardization of terminology relating to swirlers and swirling flow.
Unsteady Flow Characteristics in a Centrifugal Compressor With Vaned Diffuser
Authors: Abdel-Hamid A. N. , Haupt U. , Rautenberg M.
Published: March 2015

Self-excited flow oscillations in a high performance centrifugal compressor with vaned diffuser have been experimentally investigated over a wide range of operating conditions. The space and time characteristics of the flow oscillations in the compressor from inlet to outlet were measured using fast response dynamic pressure transducers on the shroud wall and blade mounted straingages. Multi-channel signal analysis techniques in the frequency domain clearly identified the onset of the oscillations and its type. Rotating stall was found to exist in certain regimes of the compressor map but did not necessarily preceed the occurrence of the surge phenomena. At compressor speeds below 13600 rpm the rotating non-uniform flow when it occurred was composed of three lobes and rotated at approximately 5–6 % of the impeller speed. Above 13600 rpm the rotating pattern changed to two lobes and rotated at approximately 16–20 % of the impeller speed. The direction of rotation of both patterns was opposite to that of the impeller. Analysis of the performance characteristics of the compressor components prior to and during flow oscillations indicates that the relative magnitude of the flow fluctuations in the semi-vaneless space downstream of the impeller are the largest which points towards the close relationship between the conditions leading to the onset of the oscillations and the flow details in this region of the compressor. Additional confirmation of this relationship is obtained from comparison between the results obtained in this study and those obtained when the same compressor was operated with a vaneless diffuser.
Numerical Computation of Unsteady Flows at Low Frequencies in the Last Stage of a Steam Turbine
Authors: Lattermann R. , Wachter J.
Published: March 2015

The asymmetric flow field downstream the final stage of steamturbines causes an unsteady aerodynamic loading of the rotor in the range of the lower blade eigenfrequencies. A numerical solution for the time-dependent Euler equations is presented for a complete turbine stage, varying the outlet pressure sinusoidally in the rotating frame of reference. A two-dimensional blade-to-blade flow model is used including variable streamsheet thickness and changing radii. The equations are solved by an explicit time-marching finite difference algorithm of second order accuracy in space and time. Additionally the quasi-steady solution is compared with measurements in a model steam turbine.
Analytical Prediction of the Unsteady Lift on a Rotor Caused by Downstream Struts
Authors: Taylor A. C. , Ng W. F.
Published: March 2015

A two-dimensional, inviscid, incompressible procedure is presented for predicting the unsteady lift on turbomachinery blades caused by the upstream potential disturbance of downstream flow obstructions. Using the Douglas-Neumann singularity superposition potential flow computer program to model the downstream flow obstructions, classical equations of thin airfoil theory are then employed, to compute the unsteady lift on the upstream rotor blades. The method is applied to a particular geometry which consists of a rotor, a downstream stator, and downstream struts which support the engine casing. Very good agreement between the Douglas-Neumann program and experimental measurements was obtained for the downstream stator-strut flow field. The calculations for the unsteady lift due to the struts were in good agreement with the experiments in showing that the unsteady lift due to the struts decays exponentially with increased axial separation of the rotor and the struts. An application of the method showed that for a given axial spacing between the rotor and the strut, strut-induced unsteady lift is a very weak function of the axial or circumferential position of the stator.
Erosion Research on the U.S. Department of Energy Fossil Energy Materials Program
Authors: Judkins R. R. , Bradley R. A.
Published: March 2015

Research projects on the U.S. Department of Energy Fossil Energy Materials Program are investigating the mechanisms of erosion and erosion-corrosion of alloys and cermets used in fossil energy systems. The aim is to obtain an understanding of erosion mechanisms that will provide the basis for the development or modification of alloys and cermets with improved erosion resistance. Projects on this program are outlined. Results of recent research activities are presented, and plans for future research are described.
An Engineering Method for Solving Axial Flow Cascade Inverse Problem
Authors: Cai R.
Published: March 2015

The full inverse problem of axial flow cascade, to design an axial flow cascade with prescribed velocity distribution along the cascade blade, is solved with the Mean-Stream-Line Method (MSLM) originally proposed by Wu and Brown (1952). The selection of initial condition, the approach of iteration, the smoothing technique of calculation data, the determination of pitch/chord ratio and the applicable range of this method are discussed. Since this method is extremely simple and rapid, it is able to design a cascade very quickly and to program a design computer code with a very small computer. Some calculation examples are given and the calculation results are compared with other methods.
Aerodynamic Characteristics Optimization of an Axial Turbine Exhaust Hood by Tests Based on an Orthogonal Design Approach
Authors: Mao S. K. , Wei Y. Z. , May Y. L.
Published: March 2015

The shape of an axial exhaust hood is characterized by a rather complicated geometry. The aerodynamic characteristics optimization of such a hood involves considerable difficulty. An optimization method of conducting tests based on an orthogonal design approach is presented. Through model tests of a limited number of versions an optimized version can be selected out of several thousand or so versions composed of different values of a few geometrical parameters. By using the method on a group of exhaust hoods consisting of diffusers and volutes, an optimized configuration and several sub-optimized versions are obtained. Evaluation tests of the optimized version and sub-optimized versions have confirmed their superior performance. The present method can likewise be applicable to exhaust hoods of other axial-flow turbomachines.
A Discussion of the Mean S2 Stream Surfaces Applied to Quasi-Three-Dimensional Calculation Programs for Turbomachinery Design
Authors: Xujin Zhu , Zhongqi Wang
Published: March 2015

This paper attempts to clarify the various definitions of the “S2m” surfaces applied to quasi-3-d inviscid flow computation in turbomachinery by adopting an extended concept of true S2 stream surface (PAG S2) in the discussion. It is indicated that PAG S2 gives a more universal and applicable model to solve the pitch -averaged flow properties through turbine blade passages, especially when a non-orthogonal curvilinear coordinate system is introduced into its governing equations in the present paper.
Theoretical Principles of the Cylindrical, 2-Hole Pneumatic Probe
Authors: Birri I. , Voegtli D.
Published: March 2015

Appropriate monitoring of the compressor mass flow is of very great importance for compressor condition monitoring systems. This paper describes a system for monitoring the compressor mass flow using a Pitot cylinder. It further describes the information and experience gained in testing this measurement system both in the wind tunnel and in BBC Type 8 gas turbines.
Experimental Aerodynamic Analysis Relative to Three High Pressure Ratio Centrifugal Compressors
Authors: Ribaud Y.
Published: March 2015

The test results of three high pressure ratio centrifugal compressors are analyzed. Two of them show one or two discontinuities in the surge line. A careful study of the different experimental parameters indicates the existence of three different operating zones for the rotor. For the low inlet flow coefficients, two recirculations take place in the rotor: one at the inlet and the other at the outlet. For moderate flow coefficients, the outlet recirculation disappears. In these regions, the occurrence of these recirculations is explained and a simple model is given. The inlet recirculation can stabilize the flow if a 2D blade stall occurs but it is not possible in the third zone where the inlet flow coefficient is higher than the critical value.
TG 50: The Evolution of a 100 MW Single Shaft Gas Turbine Through 12 Years of Operating Experience
Authors: Merola A.
Published: March 2015

The paper deals with the development of TG 50 gas turbine and its evolution in the years from the original to the present configuration with mention of substantial improvements in both compressor and turbine sections that initiated the growth of power output from the original 75 MW to the 110 MW present rating.

Successful solution of some basic operating problems encountered mainly in the compressor section, required quite an extensive research and development work.

In addition, comprehensive test programs have been carried out for the development of the present configuration and for the confirmation of the validity of the selected solutions.
Spray Performance of a Hybrid Injector Under Varying Air Density Conditions
Authors: Jasuja A. K.
Published: March 2015

The atomization characteristics of a fuel-air mixture preparation cum placement device featuring a conventional dual-orifice pressure atomizer spraying into a narrow diameter, airstream carrying tube are outlined in this paper. The experimental tests were carried out on gas oil over a range of ambient air pressures. A well established laser light-scattering technique was employed for dropsize measurements. The spray quality data collected in the present investigation allows some interesting comparisons against conventional airblast and pressure atomized spray data.
Applied Reliability/Maintainability Methodology as a Function Within Life Cycle Cost
Authors: Callis C. L. , Curry C. E.
Published: March 2015

This paper demonstrates application of reliability and maintainability (R&M) factors to determine supportability of aircraft turbine engines. R&M factors are expressed as operating and support parameters consistent with those required for LCC analysis as well as operating support level determinations.
Economic Justification of Magnetic Bearings and Mechanical Dry Seals for Centrifugal Compressors
Authors: Uptigrove S. O. , Harris T. A. , Holzner D. O.
Published: March 2015

The method for calculating the economic justification related to the use of active magnetic bearings and mechanical dry seals in centrifugal compressors is presented. This evaluation is based on the initial purchase price, and the associated operational and maintenance savings over standard oil bearings and oil seal systems. The economic evaluation is presented for both the retrofit of existing equipment and for the installation into new equipment. Although the economics are shown for centrifugal compressors, the same basic philosophy can be used to evaluate the economic justification of magnetic bearings for any type of rotating machinery.

Different areas of potential cost savings are discussed, including a method of calculating the associated savings. In addition, an example calculation for a specific compressor is presented. It must be emphasized that the economic benefits and the associated costs are highly dependent on the type and size of compressor as well as the particular application.
Reliable Operation of Gas Turbines on Crude Oil
Authors: Maderni L. , Gabella S.
Published: March 2015

The paper deals with design criteria and operating experience of Authors’ Company Gas Turbine Power Plants operating on crude oils from different sources. In particular a group of power stations located in Middle East is described, where crude oils from different fields are used. While two of the above power stations use basically the same crude oil, the other ones are fed by different fuel sources. Accordingly, different fuel handling and treatment plants have been selected, different problems have been encountered and different operating experiences have been accumulated.

The positive operating results obtained confirm that reliable operation on crude oil requires each individual application be “tailor made” on the basis of the knowledge of the relevant fuels properties.
Investigation of High-Altitude Ignition Performance of Several Chinese Jet Fuels With Different Properties
Authors: Chen Neng-Kuen
Published: March 2015

Investigation of high-altitude ignition performance of several Chinese jet fuels with different properties has been conducted at a simulated altitude facility. Jet fuels were tested in a small pilot combustion chamber taken from an existing aeroengine. The fuels consist of Da-Qing oil, Da-Gang oil, Nan-Jing oil, Gu-Dao oil (so called as high density fuel) as well as a compound oil. Test results show that the lower the fuel density (its viscosity is also lower, but vapour pressure is higher), the better the high-altitude ignition performance. The high-altitude ignition performance of high density fuel is rather bad, but can be significantly improved by mixing it with a small quantity of low density oil (about 10 percent). Using a small flow number atomizer may obviously improve the weak ignition limit of the high density fuel, but the ignition velocity-pressure limit and the rich ignition limit are shrunk. Test results also show that prevailing theory model for spark ignition is feasible.