bluuebunny/crossref_metadata_2025 huggingface dataset:
Challenges and prospects for interpreting long‐term phytoplankton diversity changes in Lake Zurich (Switzerland)
Authors: Pomati Francesco , Tellenbach Christoph , Matthews Blake , Venail Patrick , Ibelings Bas W. , Ptacnik Robert
Published: March 2015

Analysing and interpreting long‐term phytoplankton time series present a number of challenges, arising from potential historical inconsistencies in data collection and taxonomic identification of organisms. In a previous paper, Pomati et al. (2012) found a remarkable increase in phytoplankton diversity that coincided with oligotrophication and warming of Lake Zurich over a 32‐year period. These findings were recently challenged on the basis of potential biases in detection limits and taxonomic classification over the time series (Straile, Jochimsen & Kümmerlin, 2013). We agree that being cautious with long‐term phytoplankton data series is extremely important, but argue that the increase in richness detected in Lake Zurich cannot be due only to methodological bias.

Following additional analysis of the Lake Zurich phytoplankton dataset, we found that the shift in taxon detection limits reported by Straile et al. (2013) is not supported by the data and stems from a rounding error in the calculation of density in the dataset available to those authors. We found a decline in the proportional abundance for common taxa, an increase in the annual prevalence of taxa and reduced community turnover over the time series. Taken together, the data clearly indicate a trend of decreasing dominance, while more taxa coexist simultaneously. We also argue that the taxonomic classification has been robust (at least at the family level) and propose a diagnostic plot that can help detect an unbiased signal of change in plankton richness through time.

Straile et al. (2013) observed perfect synchrony in species occurrence between Lake Zurich and nearby Lake Walen. While we agree that such perfect synchrony in community composition can reflect a bias in the database compilation, it can also be an important ecological signal of changes in regional species pools that deserves further analysis.

We conclude that the results of Pomati et al. (2012) are robust and not substantially undermined by the criticisms of Straile et al. (2013). More generally, it is indeed possible to extract meaningful signals of biodiversity change from long‐term phytoplankton monitoring datasets, provided there is a clear understanding of how the data have been sampled, recorded and analysed over the history of the time series.
Human Resource Development in SMEs: A Systematic Review of the Literature
Authors: Nolan Ciara T. , Garavan Thomas N.
Published: March 2015

Human Resource Development (HRD) in small and medium‐sized enterprises (SMEs) is a significant area of scholarship. However, the cumulativeness of research on HRD in SMEs remains relatively low when compared to HRD generally. This paper reports a systematic literature review (SLR) to synthesise research in this area. A disciplined screening process resulted in a final sample of 117 papers published in 31 journals from 1995 to 2014. The synthesis of these empirical and theoretical studies revealed that: (a) the literature utilises a narrow range of theoretical and conceptual perspectives; (b) HRD is being investigated across a variety of SME contexts, themes and units of analysis; (c) researchers define HRD in multiple ways and use a diverse set of measures of HRD activity; (d) there is significant potential for future research across the SME and HRD disciplines, SME settings and beyond existing theoretical perspectives. We offer suggestions for further advancing the development of this area of research in terms of theory, content and methodology.
Effect of TiO2 Doping on the Structure and Microwave Dielectric Properties of Cordierite Ceramics
Authors: Wu Song , Song Kaixin , Liu Peng , Lin Huixing , Zhang Fangfang , Zheng Peng , Qin Huibin
Published: March 2015

The (1−x)Mg2Al4Si5O18–xTiO2 |(1−x)MAS‐xT| (0 ≤ x ≤ 0.35) cordierite ceramics are fabricated by solid‐state reaction method for obtaining near‐zero temperature coefficient of resonant frequency (τf). The XRD and SEM results show that (1−x)MAS‐xT (0 ≤ x ≤ 0.10) ceramics exhibit single cordierite solid solution, whereas as 0.15 ≤ x ≤ 0.35, present composite phases of Mg2Al4Si5O18 solution and TiO2. Rietveld refinements of XRD data suggest that the [(Si4Al2)O18] hexagonal shape in cordierite structure happens to alternate change from nonsymmetrical hexagonal rings to almost centrosymmetrical equilateral rings as x increases to 0.10 comparing to that of x = 0. As Ti4+ ions squeeze into the [(Si4Al2)O18] rings structure, the orientation and shapes of the rings begin to rotate and expand from initial state of [1–20] (x = 0) to near [210] direction (x = 0.10), and then continue to expand toward close to [110] direction (x = 0.25). Due to centrosymmetry adjustment of [(Si4Al2)O18] hexagonal rings and of other microstructure factors improvement, the (1−x)MAS‐xT (x = 0.10) cordierite solution achieves optimum quality factor Qf: εr = 6.3, Qf = 55 400 GHz (17.6 GHz), τf = −21 ppm/°C. The (1−x)MAS‐xT (x = 0.25) composites obtain a near‐zero temperature coefficient of resonance frequency: εr = 6.8, Qf = 37 800 GHz (18.4 GHz), τf = −0.2 ppm/°C.
Genetic and morphological variability of the European mudminnowUmbra krameri(Teleostei, Umbridae) in Serbia and in Bosnia and Herzegovina, a basis for future conservation activities
Authors: Marić S. , Snoj A. , Sekulić N. , Krpo‐Ćetković J. , Šanda R. , Jojić V.
Published: March 2015

As a basis for future conservation activities, the genetic and external body morphology variability of the European mudminnowUmbra krameri, a highly endangered fish species in Serbia and in Bosnia and Herzegovina, was determined for existing populations with the use of molecular markers (mitochondrial and microsatelliteDNA) and geometric morphometric methods. MitochondrialDNAcytochrome b gene analysis revealed two previously undescribed haplotypes: Da1 (the Lugomir population from the Danube River basin) and Sa1 (the Bakreni Batar and the Gromiželj populations from the Sava River system), with a corresponding genetic distance of 0·7%. Paired values ofFSTandDASdistances for microsatellite marker data show that the difference between the Danube and the Sava populations is seven to nine times higher than the difference between the populations within the Sava River system. Geometric morphometric analyses also support a clear separation of the Lugomir population from the Bakreni Batar and the Gromiželj populations. The analysis of the body shape variation, however, indicates a significant difference between the two genetically indistinguishable Sava populations. The observed genetic and phenetic relationships of the analysed mudminnow populations most probably represent a consequence of historical, geographical and ecological factors. These results will offer guidelines for future protection, conservation and sustainable management of this species in the region.
Interdisciplinary Communication and Collaboration Among Physicians, Nurses, and Unlicensed Assistive Personnel
Authors: Lancaster Gwendolyn , Kolakowsky‐Hayner Stephanie , Kovacich Joann , Greer‐Williams Nancy
Published: March 2015

Purpose

Historically, health care has primarily focused on physician, nurse, and allied healthcare provider triads. Using a phenomenological approach, this study explores the potential for hospital‐based interdisciplinary care provided by physicians, nurses, and unlicensed assistive personnel (UAPs).

Design

This phenomenological study used a purposive nonprobability, criterion‐based, convenience sample from a metropolitan hospital.

Theoretical Foundation

Malhotra's (1981) Schutzian lifeworld phenomenological orchestra study provided the theoretical basis for the conductorless orchestra model, which guided this study. In an orchestra, each member sees and hears the musical score from a different vantage point or perspective and has a different stock of knowledge or talent; however, members work together to produce a cohesive performance. Like the orchestra, individual talents and perspectives of physicians, nurses, and UAPs can be collaboratively blended to create a symphony: enhanced patient‐centered care.

Methods

Qualitative semistructured face‐to‐face, individual interviews were carefully transcribed and coded with the aid of NVivo 9, a qualitative data analysis software program, to discover emergent patterns and themes.

Findings

The study suggests that most of the time physicians, nurses, and UAPs operate as separate healthcare providers who barely speak to each other. Physicians see themselves as the primary patient care decision makers. Many physicians acknowledge the importance of nurses’ knowledge and expertise. On the other hand, the study indicates a hierarchical, subservient relationship among nurses and UAPs. Physicians and nurses tend to work together or consult each other at times, but UAPs are rarely included in any type of meaningful patient discussion.

Conclusions

Since physicians, nurses, and UAPs each provide portions of patient care, coordination of the various treatments and interventions provided is critical to prevent errors and fragmentation of care. Tensions, misunderstandings, and conflicts caused by differences of opinions and interests can interfere with effective interdisciplinary communications and collaboration. Improving patient safety in the hospital requires addressing the current hierarchical professional structure inherent in healthcare delivery. A hospital patient care model based on the conductorless orchestra model would mitigate hierarchy; recognize physician, nurse, and UAP contributions to care; promote improved communication and collaboration; and enhance patient safety.

Clinical Relevance

Study results provide additional information supporting interdisciplinary communication and collaboration education and training among physicians, nurses, and UAPs to support positive patient care outcomes.
Improved pharmacodynamics and pharmacokinetics after i.v. application of peginterferon alfa‐2a in hepatitis C null responders
Authors: Fülöp Balazs , Biermer Michael , Cornberg Markus , Wedemeyer Heiner , Port Kerstin , Heyne Renate , Zeuzem Stefan , Peiffer Kai‐Henrik , Welzel Tania , Herber Adam , Buggisch Peter , Moser Christoph , Stoll Sabine , Alshuth Ulrich , Berg Thomas
Published: March 2015

Background & Aim

Mechanisms of non‐responsiveness to peginterferon alfa‐2a are not completely understood. Inadequate plasma levels may contribute to reduced response. The aim of this prospective, multicentre, crossover, Phase 1 study was to evaluate the pharmacokinetics and viral kinetics of intravenous vs. subcutaneous peginterferon alfa‐2a in patients with genotype 1 chronic hepatitis C infection who showed null response to previous peginterferon/ribavirin.

Methods

Patients were randomized in four treatment arms to subcutaneous or intravenous peginterferon alfa‐2a 180 μg, once or twice weekly for 2 weeks. After a washout phase of 6 weeks, patients first receiving intravenous administration switched to subcutaneous or vice versa for additional 2 weeks.

Results

Intravenous administration of pegylated interferon resulted in a stronger and faster decline in HCV RNA than subcutaneous administration with a maximum decline of 1.17 log10 vs. 0.41 log10 or 1.32 log10 vs. 0.54 log10 after a once or twice weekly application, respectively. Pharmacokinetic studies revealed significantly higher maximum concentration (Cmax)0–12 h and Cmax 0–7 d following intravenous administration, irrespective of dosing frequency A rapid rebound in HCV RNA was observed in all treatment arms. Adverse events occurred more frequently following intravenous administration.

Conclusion

Intravenous administration of peginterferon alfa‐2a results in considerably higher plasma concentration and a stronger decline in HCV RNA and offers an interesting approach in order to overcome interferon non‐responsive state in patients with full null response to previous peginterferon/ribavirin combination therapy.
Habenaria parviflora (Orchidaceae), extension of its austral distributional limit and new synonymy
Authors: Sanguinetti Agustín
Published: March 2015

An extension of the austral distributional limit of Habenaria parviflora Lindl. and a new record for the orchid flora of Buenos Aires province is reported on the basis of specimens collected from the northwestern hills of the Tandilia System. Habenaria uruguayensis Garay is found to be a synonym of H. parviflora based on studies of original material, protologues and previous bibliography. A lectotype is designated for H. parviflora.
Transabdominal Ultrasonography for Pregnancy Diagnosis and Estimation of Gestational Age in Dromedary Camels
Authors: Ali A , Derar R , Al‐Sobayil F
Published: March 2015

Contents

The objective of this study was to evaluate the use of transabdominal ultrasonography as a method for pregnancy diagnosis and establish some foetal biometrics guidelines of pregnancy staging. Transabdominal ultrasonography was performed weekly on six pregnant camels from the 4th to the 19th week and at 2‐week intervals from the 20th to the 52nd week of gestation. Six areas were selected for examination: caudal abdominal (CAA), inside the thigh, above the base of the udder; middle abdominal (MIA), from the base of the udder to the umbilicus; and cranial abdominal (CRA), from the umbilicus to the xiphoid cartilage. Several foetal parameters including orbital diameter (ORD), biparietal diameter (BPD), abdominal diameter (ABD), chest depth (CHD) and ruminal diameter (RUD) were measured using standardized scan plans. The relationships between the gestational age and the foetal parameters were evaluated. From the 6th to the 12th week, the conceptus was always observed through the left CAA approach. Between the 13th and 27th week, the foetus was entirely visualized by the MIA examination. From the 28th to the 52nd week, the conceptus was mainly detected through the left CRA approach. The foetal parameters were measured frequently during mid‐ and late gestation. All regression and correlation coefficients were highly significant (p < 0.0001). In conclusion, transabdominal ultrasonography was shown to be a reliable technique for pregnancy diagnosis and estimation of gestational age in dromedary camels.
Generation of Foxo3‐targeted Mice by Injection of mRNAs Encoding Transcription Activator‐like Effector Nucleases (TALENs) into Zygotes
Authors: Zhu P , Liu Q , Liu S , Su X , Feng W , Lei X , Liu J , Cui K , Huang B , Shi D
Published: March 2015

Contents

In this study, for exploring the mechanism of forkhead box O3(Foxo3) participating in regulation of the activation of primordial oocytes, Foxo3‐targeted mice were generated by injection of mRNAs encoding transcription activator‐like effector nucleases (TALENs) into mouse zygotes. The TALEN sites were designed with high conservative homologous region among pig, bovine, buffalo and mouse by commercial bio‐companies. The TALENs mutagenic non‐homologous end‐joining (NHEJ) repair activity were determined to be 31.3% in human embryonic kidney 293T (HEK‐293T) cells by dual luciferase reporter assay system. Then, we firstly injected TALEN‐mRNAs into the cytoplasm of mouse zygotes by micromanipulation, and four of 48 mouse blastocysts were identified as mutation by sequencing. Subsequently, by the method of TALEN‐mRNAs injected into the zygotes with pronucleus micromanipulation technique, we obtained seven Foxo3 mutants of 20 FVB/NJ backgrounds mice which were Foxo3‐independent alleles with frameshift and deletion mutations. It was very interesting that all seven were heterozygous mutants (Foxo3−/+), and the gene mutagenesis rates of the mice reached 35%. The five Foxo3 mutant females were all infertile in the following 6 months after birth. The histological examination results showed that there were rare primordial follicles and primary follicles in the ovary of Foxo3 mutant compared to that of wide‐type female mice. Moreover, one of two mutant males was subfertile and another was fertile normally. Those results suggested that the mutant of Foxo3 severely affected the fertile ability of female and perhaps male in some degree; furthermore, an even more efficient TALENs‐based gene mutation method has been established to be poised to revolutionize the study of mouse and other species genetics.
Heart rate recovery after the 6‐min walk test is related to 6‐min walk distance and percutaneous oxygen saturation recovery in patients with COPD
Authors: Shiroishi Ryota , Kitagawa Chika , Miyamoto Naomi , Kakuno Nao , Koyanagi Harumi , Rikitomi Naoto , Senjyu Hideaki
Published: March 2015

Heart rate recovery (HRR) after maximal load exercise affects mortality in chronic obstructive pulmonary disease (COPD). However, the associations of clinical characteristics with HRR after the 6‐min walk test (6MWT), which is defined as a submaximal load test, remain unclear. We showed that HRR in patients with COPD after 6MWT was related to 6‐min walk distance and percutaneous oxygen saturation recovery. HRR after the 6MWT may be useful to assess exercise capacity in COPD.
Prediction of Arteriovenous Fistula Dysfunction: Can it be Taught?
Authors: Rosenberg Joel E. , Yevzlin Alexander S. , Chan Micah R. , Valliant Amanda M. , Astor Brad C.
Published: March 2015

Physical examination (PE) is an excellent means of predicting arteriovenous fistula (AVF) dysfunction. Although quick and inexpensive,PEis seldom used as a tool to assess stenosis by general nephrologists, dialysis nurses, and dialysis technicians. Previous studies have demonstrated thatPEcan be taught to interventional specialists, but the perception remains that it is too complex to be performed by other health care professionals. We hypothesized that the physical exam can be taught to a nonmedical professional, and that, with time, it would be comparable to the physical exam performed by a full‐time interventional specialist. An undergraduate student and an interventional specialist (MD) examinedAVFfor dysfunction in a tertiary care hospital over a 6‐month period.PEwas performed on patients who were suspected of having dialysis access dysfunction and were referred for angiography and intervention (n = 49). Physical exam findings were categorized blindly by each examiner into four categories of lesion location: inflow, outflow, both, or neither. Data were privately recorded and compared to the gold standard of angiographic results. Potential confounding variables, including age, gender, diabetic status, and location ofAVFwere recorded. Weighted Cohen's kappa value was used as a measurement of the level of agreement beyond chance between the diagnoses made by physical exam and angiography. The full‐time interventional specialist demonstrated correct prediction of lesion location of 89.8% (kappa = 0.850), while the undergraduate student had a correct prediction of 77.6% (kappa = 0.625). The student's performance, however, differed significantly over time. The student correctly predicted the location of the lesion in 6 (42.9%) of the first 14 patients (kappa = 0.082), compared to 32 (91.4%) of the last 35 patients (kappa = 0.855). We suggest that physical exam of AVF can be taught to a nonmedical professional in a short duration of time and the predictive value of the exam can be similar to that of an interventional specialist.
A Comparison of IGCC Plants for Grass Roots and Repowering Applications
Authors: Lehman S. J. , Robson F. L. , Smith M. J. , Fuess D. J. , Crouse F. J. , Westsik J. H.
Published: March 2015

The Integrated Gasification Combined Cycle (IGCC) has the potential to be one of the most efficient and environmentally acceptable methods of generating electric power. To date, the majority of IGCC concepts have been for new grass roots power plants located at a fictitious mid-western site and burning Illinois No. 6 coal. Under DOE-sponsorship, conceptual design studies were made of both a grass roots installation and a repowering of the Albany Plant of the Niagara Mohawk Power Corporation. Both designs are based upon the use of Texaco gasifiers using a Western Pennsylvania coal. The estimated performance, economics and emissions are compared for these power plants.
Droplet Size Effects on NOx Formation in a One-Dimensional Monodisperse Spray Combustion System
Authors: Sarv H. , Nizami A. A. , Cernansky N. P.
Published: March 2015

A one-dimensional monodisperse aerosol spray combustion facility is described and experimental results of post flame NO/NOx emissions are presented. Four different hydrocarbon fuels were studied: isopropanol, methanol, n-heptane, and n-octane. The results indicate an optimum droplet size in the range of 48–58 microns for minimizing NO/NOx production for all of the test fuels. This NOx behavior is associated with droplet interactions and the transition from diffusive type of spray burning to that of a prevaporized and premixed case. Decreasing the droplet size results in a trend of increasing droplet interactions, which suppresses temperatures and reduces NOx. This trend continues until prevaporization effects begin to dominate and the system tends towards the premixed limit. The occurrence of the minimun NOx point at different droplet diameters for the different fuels appears to be governed by the extent of prevaporization of the fuel in the spray, and is consistent with theoretical calculations based on each fuel’s physical properties.
Optimizing the Performance of Compressed Air Energy Storage (CAES) Compressor and Turbine Trains
Authors: Marinacci Daniel J. , Bumgarner James M. , Bonk Joseph S. , Schainker Robert B.
Published: March 2015

This paper is a result of work done by the Westinghouse Electric Corporation on a $1.8 million, 3 1/2 year study funded by DOE and EPRI.

The potential future market for Compressed Air Energy Storage (CAES) system is substantial. The savings realized by utilizing CAES power plants can be very attractive with the proper generation mix.

The thermodynamic parametric performance studies that were conducted to screen the various aquifer charging and discharging cycles are discussed. Equations are presented to directly calculate the optimum (minimum required total compressor work and air cooler heat rejection) intercooler(s) location for a compressor train utilizing one and two inter-coolers. An equation is also presented which directly determines the reheat combustor location required to maximize the turbine train output. A discussion is included why the performance of CAES power cycles must be optimized by considering the total power production energy costs not on a basis of maximum turbine output power or heat rate.

Hardware and economic considerations which lead to CAES LP turbomachinery component standardization are discussed. Such standardization allows a manufacturer to economically adapt its CAES turbomachinery to a range of different air storage pressures.
Advancing the Technology of the Large Utility-Size Gas Turbine Burning Coal-Derived Fuel
Authors: Manning G. B. , Boyum W. B.
Published: March 2015

This paper describes the status of the developmental activities underway for advanced, utility-sized gas turbines. These long range, high risk activities initiated in the 1970s in response to the energy crisis situation, have not yet reached a sufficient maturity level to guarantee timely commercial implementation of the developing technology. Technological hurdles still remain to be addressed if the original programmatic goals are to be achieved and the efficiency, hence the economic, benefits are to be gained.
Mathematical Model of Transient Temperature Distribution and Thermal Stresses in Large Steam Turbine Rotors
Authors: Sasiadek J. , Kwok C. K.
Published: March 2015

The most important problems encountered in power plants are related to cold start-up, hot start-up, daily and seasonal variation in load. These problems are specially critical for high power units above 525°C and 10.5 MN/m2. As a result of higher thermal capacity of the thicker components in larger power units, the temperature gradient and thermal stresses assumed much higher values. It is, therefore, particularly important during transient operation conditions to know the temperature distribution and thermal stresses of rotors. One of the most common concerns is how fast can a turbine be started without significant damage. If the turbine is loaded very rapidly, high temperature gradient and excessive thermal stresses can easily damage the machine.

A concept was developed whereby an on-line computer was used to control the start-up and load variation operations of the turbine. The feasibility of such concept depends upon the knowledge of the instantaneous temperature distribution and thermal stresses of the turbine rotors. This paper presents a 2-D mathematical model of the transient temperature distribution as well as thermal stresses of the rotor. The mathematical model was simulated in the computer and ADI method was used for the solution of the governing equations. Discussions will be made of the procedure of coupling this mathematical model with on-line computer for optimum control of start-up and load variation schedule.
Development Towards a Fuel Flexible Combustion System
Authors: Willis J. D.
Published: March 2015

Due to limited reserves of crude oil and natural gas, it is generally accepted that fuel prices will continue to rise. Associated with cost increase is a strong possibility that quality of petroleum distillate fuels will deteriorate, particularly for power generation. Several techniques are available or are being developed to produce fuels from non-petroleum sources, including liquids and gases from coal and vegetation. Liquid fuels will fall into two categories: a synthetic distillate with lower hydrogen content and a significant amount of fuel-bound nitrogen unless further hydrogenation is carried out; and light alcohol fuels with lower calorific values than present distillates. Gases produced will vary considerably dependent on the process and original material, but a common factor will be medium to low calorific values in terms of Btu/scf and a tendency to have high inert gas content. The efficiency of energy conversion of various materials is higher when gas is produced (70–85%) than liquid (40–65%). The efficiency of conversion being the ratio of the available energy from the products to the input energy of the feed.
Full Scale Catalytic Burner Testing With No. 2 Oil for Combustion Turbine Application
Authors: Scheihing Paul E. , Pillsbury Paul W. , Piaia Thomas A. , Kitaplioglu Omer
Published: March 2015

Full scale laboratory tests were performed by the Combustion Turbine Systems Division of the Westinghouse Electric Corporation to explore the feasibility of using catalytic burners in industrial combustion turbines to reduce emissions. Catalytic elements were provided by the Engelhard Industries Division of Engelhard Corporation, and No. 2 distillate fuel was burned in single combustor rig tests at the pressure, airflow, and inlet temperature equivalent to those in a large combustion turbine. Variations of a concept that employed a conventional preburner upstream of a catalytic secondary, and sidewall fuel injection were tested and evaluated for fuel/air presentation to the catalyst. Results indicated ultra-low NOx emissions and that, with development in secondary fuel/air preparation, the concept is technically feasible.
Effect of Gas and Metal Temperatures on Gas Turbine Deposition
Authors: Cohn Arthur
Published: March 2015

A number of test projects have measured the deposition rates of the combustion products of residual-oil-type fuel. This paper analyzes those results to obtain information on he effects of the gas and metal temperatures on the deposition rates. While the data is far from complete, certain major trends result from the data. For a given gas temperature, the deposition rate increases with decreasing metal temperature below the level of the gas temperature until a maximum rate is reached at ∼1200°F (650°C); then the deposition rate decreases as the metal temperature is further lowered and becomes small at metal temperatures near 700°F (370°C). For a given metal temperature, the deposition rate increases with higher gas temperatures. This may occur at an increasing rate for gas temperatures above 2000°F (1100°C).
Water Cooled Gas Turbine Development Summary
Authors: Cohn Arthur
Published: March 2015

The EPRI projects for the development of water-cooled gas turbine power plants have been completed, while the DOE project on this subject (HTTT) is completing Phase II with little likelihood for further funding. This paper presents the prospects of water-cooled power plants as currently evaluated at EPRI. It is concluded that: water cooling designs for the stationary components are commercially ready, but technology development work is still required for the rotating components; water cooled turbines can have much lower ash deposition and corrosion rates than air cooled ones when firing on ash-containing fuels; water cooling provides considerable increase in specific power, but there is little advantage, if any, in efficiency compared to air cooling. The water-cooled gas turbine has its main attractiveness for operation with ash-containing fuels at base load. However, since this type of operation is not currently foreseen for American utility practice, the near-term continued development of the water-cooled gas turbine power plant is not expected to proceed.
The Characteristics and Capabilities of Heavy Duty Gas Turbine Multiple Combustor System: Part I — General Description, Combustor Design and Field Operations
Authors: Pavri R. E. , Wilhelm C. F.
Published: March 2015

The fundamental characteristics and capabilities of the heavy duty gas turbine multiple combustor system are described. General configurations, combustor design and uprate capabilities and field operations are presented in Part I. Part II explores the emission characteristics and alternate fuels capability. It is shown that the multiple combustor system has the flexibility to be adopted to changing emission requirements, high temperature and airflows for better performance and different fuels at the same time providing easy field operations.
Parametric Study of Flame Radiation Characteristics of a Tubular-Can Combustor
Authors: Humenik Francis M. , Claus Russell W. , Neely Geralyn M.
Published: March 2015

A series of combustor tests were conducted with a tubular-can combustor to study flame radiation characteristics and effects with parametric variations in combustor operating conditions. Two alternate combustor assemblies using a different fuel nozzle were compared. Spectral and total radiation detectors were positioned at three stations along the length of the combustor can. Data were obtained for a range of pressures from 0.34 to 2.07 MPa (50 to 300 psia), inlet temperatures from 533 to 700K (500 to 800°F), for Jet A (13.9% hydrogen) and ERBS (12.9% hydrogen) fuels, and with fuel-air ratios nominally from 0.008 to 0.021. Spectral radiation data, total radiant heat flux data, and liner temperature data are presented to illustrate the flame radiation characteristics and effects in the primary, secondary, and tertiary combustion zones.
Temperature and Dilution Effects in Soot Mass Concentration Measurements
Authors: Clark J. A. , Moser D. W. , Best W. D. , Thompson N. A.
Published: March 2015

Measurements are made of soot mass concentration in a luminous, liquid fuel spray, diffusion flame at atmospheric pressure. Intrusive sampling probes are used to study the effects of sampling rate, cooling, nitrogen-dilution ratio, and tip geometry on the mass of soot particles deposited on filters. Probe diameters have been kept small to minimize disturbance to the flow-field.

Relative soot concentrations are observed to be lowest for uncooled probes, higher for water-cooled probes and still higher for probes with both water cooling and nitrogen injection. Furthermore, soot concentration steadily rises as the nitrogen/sample dilution ratio is increased from zero to as high as 1.5. Sampling rate has little effect on soot concentrations under most, but not all, sampling conditions.
Performance Testing in Oxygen of a High-Pressure, High-Volume Oxygen Compressor
Authors: Tessier M. J. , Granger R. A.
Published: March 2015

In connection with the Coal Gasification Program of the U.S. Department of Energy, a need was identified for a high-pressure, high-volume oxygen compressor. At the time, the highest steady operating pressure available from commercial-sized turbocompressors was about 65 bar (950 psia), which was being used in the partial oxidation process for ammonia or methanol synthesis. For advanced coal conversion plants, compressors operating at 115 bar (1667 psia) would be needed.

The U.S. Department of Energy (DOE) entered into an agreement with the West German firm of Mannesmann Demag, AG, to develop a high-pressure oxygen compressor. Mannesmann Demag designed and fabricated a third casing centrifugal compressor (to be used in a train with available compressors) having a nominal inlet pressure of 65 bar (950 psia) and a nominal discharge pressure of 115 bar (1667 psia). In exchange, the U.S. DOE agreed to fund the modification and operation of a NASA-owned test facility for testing the compressor. The facility, CTL-V, was modified and operated by the Rocketdyne Division of Rockwell International. Test management and reporting was carried out by DOE’s Energy Technology Engineering Center (ETEC), operated by Rockwell International’s Energy Systems Group.

This paper presents a brief description of the compressor test article and test facility. The test program, test results, and analysis are presented in greater detail. The scope of the test program included low- and high-pressure nitrogen shakedown tests, oxygen performance and steady-state tests, and oxygen maximum suction pressure tests.

The facility is unique because it is the only one of its kind nationally that can provide the power to drive the compressor and that has liquid oxygen/liquid nitrogen capability (the facility is utilized for development and testing of rocket engine turbopumps). Also, testing and data acquisition, reduction, and analysis were performed in a facility that normally runs tests of few minutes duration (for rocket engine components) but that had to be converted to run endurance tests lasting several hundred hours.
The NASA Broad-Specification Fuels Combustion Technology Program: An Assessment of Phase I Test Results
Authors: Fear James S.
Published: March 2015

An assessment is made of the results of phase I screening testing of current and advanced combustion system concepts using several broadened-properties fuels. The severity of each of several fuels-properties effects on combustor performance or liner life is discussed, as well as design techniques with the potential to offset these adverse effects. The selection of concepts to be pursued in Phase II refinement testing is described. This selection takes into account the relative costs and complexities of the concepts, the current outlook on pollutant emissions control, and practical operational problems.
A Systematic Computational Design System for Turbine Cascades, Airfoil Geometry and Blade-to-Blade Analysis
Authors: Ye Z.-Q.
Published: March 2015

This paper describes a systematic computational design system for two-dimensional turbine cascades. The system includes a sequence of calculations in which airfoil profiles are designed from velocity diagram requirements and specified geometric parameters, followed by an inviscid global streamline curvature analysis, a magnified reanalysis around the leading edge, and a transitional profile boundary layer and wake mixing analysis. A finite area technique and a body-fitted mesh are used for the reanalysis. The boundary layer analysis is performed using the dissipation-integral method of Walz which has been modified in the present application. Several turbine airfoil profile geometry designs are presented. Also two sample cascade design cases and their calculated performance for a range of Mach numbers and incidence angles are given and discussed.
A Variable-Geometry Combustor Used to Study Primary and Secondary Zone Stoichiometry
Authors: Briehl Daniel , Schultz Donald F. , Ehlers Robert C.
Published: March 2015

A combustion program is underway to evaluate fuel quality effects on gas turbine combustors. A rich-lean variable geometry combustor design was chosen to evaluate fuel quality effects over a wide range of primary and secondary zone equivalence ratios at simulated engine operating conditions. The first task of this effort, was to evaluate the performance of the variable geometry combustor. The combustor incorporates three stations of variable geometry to control primary and secondary zone equivalence ratio and overall pressure loss. Geometry changes could be made while a test was in progress through the use of remote control actuators. The primary zone liner was water cooled to eliminate the concern of liner durability.

Emissions and performance data were obtained at simulated engine conditions of 80 percent and full power. Inlet air temperature varied from 611 to 665 K, inlet total pressure varied from 1.02 to 1.24 MPa, reference velocity was 18.0 m/sec and exhaust gas temperature was a constant 1400 K.
Fuel Effects on the TF30 Engine (Alternate Test Procedure)
Authors: Karpovich P. A. , Masters A. I.
Published: March 2015

The objective of the Alternate Test Procedure (ATP) is to develop the capability to qualify new fuels for Navy aircraft use with a minimum of testing. The effect of fuel composition and properties on engine performance and component life has been shown to vary significantly from one engine configuration to another. The P&WA approach to the ATP has been to define fuel effects on the TF30 engine and then apply the methodology to other engines of interest to the Navy. Investigations of the TF30 conducted under the ATP Program and other Navy and Air Force Contracts have produced one of the most complete fuel effect characterizations available for any gas turbine engine. Major fuel effects which have been quantified are the relationships of lubricity to main fuel control reliability, viscosity and volatility to main burner and augmentor ignition limits, and hydrogen content to smoke and combustor life. The effects of fuel properties and composition on combustion efficiency and elastomeric seal life were found to be of secondary importance. Remaining uncertainties are the effects of fuel properties on turbine life and fuel nozzle fouling rate.
Pressurized Fluidized-Bed Combustion: A Status Report
Authors: Scott R. L. , Hoy H. R. , Roberts A. E.
Published: March 2015

The first ever pressurized fluidized-bed combustor (PFBC) came into operation at the laboratories of the British Coal Utilization Research Laboratory at Leatherhead in 1969. This operated at pressures up to 6 atmospheres and ultimately had a thermal input of 4.5 MW. In the ensuing years, six other laboratory-scale combustors with thermal inputs ranging from 0.4 MW to about 2.4 MW and with working pressures up to 20 atmospheres came into operation. Scale up of the technology began in 1980.

Comprehensive data on combustion, hot gas cleanup and environmental aspects of the technology have been accumulated and design studies have shown that combined-cycle power plant based on PFBC have the potential to provide electric power at lower busbar costs than competing advanced power generating technologies.

This paper provides an overview on the development of the technology, the technical advances made, and those in the pipeline aimed at making the system even more attractive.
Cogeneration - Interactions of Gas Turbine, Boiler and Steam Turbine
Authors: Foster-Pegg R. W.
Published: March 2015

A gas turbine cogeneration plant produces power and process steam. Under the PURPA law, surplus electric power can be sold to the local utility. Since process steam generally cannot be exported, it is better to have an excess of power than an excess of steam.

Because of low rates offered for surplus power, or for other possible reasons, an owner may not wish to sell power, so it may be necessary to operate at a power-to-steam ratio that does not match the outputs of a gas turbine with a simple heat recovery boiler. If more steam is needed, supplementary firing may be included in the heat recovery boiler.

If the need is for more power, a back pressure steam turbine can be included. This reduces the steam output by requiring higher steam pressure. Further power increase and steam reduction can be obtained with a condensing steam turbine. If neither the full steam output nor additional power is required, capital cost can be reduced by inclusion of a smaller, less-efficient heat recovery boiler.

This paper compares these means of adjusting the power and steam outputs of a gas turbine cogeneration system to obtain the most cost effective system.
Flow Instability in Low-Pressure Turbine Blade Passages
Authors: Whirlow D. K. , McCloskey T. H. , Davids J. , Chen S. , Kadambi J. R. , Farn C. L. S.
Published: March 2015

The unsteady interaction among shocks, spontaneous condensation and boundary layers were measured in a cascade of tip section turbine blades with steam conditions similar to those that would be experienced by the blade under actual field conditions.

Test conditions covered the Mach number range of 1.0 to 1.4, based upon isentropic exit conditions. Inlet temperature conditions were such as to provide fully dry runs, runs with shock and condensation being approximately coincident, and runs with the condensation occurring upstream of the shock.

Unsteady pressure data were provided by six miniature pressure transducers embedded in the suction surface of one of the blades in the region of the impingement of the trailing edge shock from the adjacent blade.

Spatial integration of the individual transducer signals provided fluctuating forces over the region measured.

Unsteady forces were generally low but the nature and level of the fluctuating forces were different near a Mach number of 1.0, where several distinct spikes were present, and responses for some frequencies reached nearly one percent of the steady forces.
300 MW Combined-Cycle Plant With Integrated Coal Gasification
Authors: Kehlhofer Rolf H.
Published: March 2015

In the past 15 years the combined-cycle (gas/steam turbine) power plant has come into its own in the power generation market. Today, approximately 30 000 MW of power are already installed or being built as combined-cycle units. Combined-cycle plants are therefore a proven technology, showing not only impressive thermal efficiency ratings of up to 50 percent in theory, but also proving them in practice and everyday operation (1) (2).

Combined-cycle installations can be used for many purposes. They range from power plants for power generation only, to cogeneration plants for district heating or combined cycles with maximum additional firing (3).

The main obstacle to further expansion of the combined cycle principle is its lack of fuel flexibility. To this day, gas turbines are still limited to gaseous or liquid fuels. This paper shows a viable way to add a cheap solid fuel, coal, to the list. The plant system in question is a 2 × 150 MW combined-cycle plant of BBC Brown Boveri with integrated coal gasification plant of British Gas/Lurgi. The main point of interest is that all the individual components of the power plant described in this paper have proven their worth commercially. It is therefore not a pilot plant but a viable commercial proposition.
Electric Utility Cogeneration Opportunities in Industrial Park Developments
Authors: Sgamboti Carl T.
Published: March 2015

The technical and institutional factors affecting the economic development of utility owned and co-owned industrial parks have been defined and evaluated. Various concepts are presented for exploiting the unique capabilities of utilities for implementing and operating economically viable industrial park projects which receive thermal energy from the adjacent utility or its subsidiary. This approach is especially attractive to utilities who are capacity limited, or have retired or soon-to-be retired units. The potential benefits to utilities for implementing cogeneration projects near existing power plants is currently being investigated under EPRI project RP1276-18. This paper covers initial observations in the study, identifies key site parameters and describes methodologies which can be used to account for the multitude of complex factors affecting the development of utility-owned or co-owned industrial park sites. Examples from the EPRI study are presented to illustrate the potential benefits and importance of site individualities.
Design and Expected Performance of 45 MWe to 100 MWe CAES Turbine Machinery
Authors: Haselbacher H. , Stys Z. S. , Karalis A. J. , Sosnowicz E. J.
Published: March 2015

The design of 220 Mwe CAES commerical turbine machinery is well known to many U.S. Utilities. Not as well known is the design and expected performance of smaller size CAES units in the 45 to 100 MWe size range. The attributes of the machinery for the smaller sizes are described in this paper. Both the 220 MWe size as well as the smaller sizes are patterned after the successfully operating BBC Brown Boveri designed and fabricated CAES turbine installed at Huntorf, West Germany.
A Gas Turbine Interactive Design System — TDSYS — for Advanced Gas Turbines
Authors: Sato T. , Aoki S. , Mori H.
Published: March 2015

The characteristics and experiences of the gas turbine interactive design system, TDSYS, are described.

The design of high performance advanced gas turbines requires complex trade-off analyses for optimization and hence it is necessary to use a highly efficient and accurate computerised integrated design system to complete the laborious design jobs in a short time.

TDSYS is an interactive design system which makes extensive use of computer graphics and enables the designers to complete a gas turbine blade design systematically in a very short time.

TDSYS has been developed and continuously improved over a period of ten years. The system has been used for the complete and retrofit design of many gas turbines including Mitsubishi MW701 and AGTJ-100A which is a high efficiency reheat gas turbine now being developed under a Japanese national project.

In this paper, typical design samples of high temperature turbines are also presented.
Corrosion/Erosion Potential of Selected Turbine Materials in a PFBC Environment
Authors: McClung James D.
Published: March 2015

A pressurized fluidized-bed combustion combined-cycle (PFBC/CC) concept represents an attractive system for generating electric power at high efficiencies while meeting environmental requirements. An integral part of the technology required for commercialization is the long-term, trouble-free operation of the gas turbine in the high-temperature effluent from the PFBC. This environment has significant potential for corrosion, erosion and deposition in the gas turbine. The occurrence of any one or combination of these three processes may result in the loss of turbine efficiency and/or reduced power output. This paper summarizes and compares recent results of experimental tests assessing the corrosion and erosion potential of selected gas turbine materials. Based on these and earlier results in simulated and actual PFBC environments, the corrosion and erosion potential of gas turbine materials is assessed.
Experiences With NOx Formation/Reduction Caused by Supplementary Firing of Natural Gas in Gas Turbine Exhaust Streams
Authors: Backlund J. C. , Spoormaker A. W.
Published: March 2015

NOx formation and reduction by supplementary firing of natural gas in gas turbine exhaust streams is discussed. Representative field data is presented and discussed. NOx formation and reduction mechanisms are related to specific burner geometries, and overall system configurations and operating parameters.