bluuebunny/crossref_metadata_2025 huggingface dataset:
Valuing Unpaid Child Care in the U.S.: A Prototype Satellite Account Using the American Time Use Survey
Authors: Suh Jooyeoun , Folbre Nancy
Published: April 2015

This paper builds on previous satellite accounts that treat households as production units, but challenges their measurement and valuation of time devoted to child care, making a case for the inclusion of supervisory child care time that does not overlap with other productive activities. We also suggest several other methodological refinements for estimates based on analysis of data from the American Time Use Survey: application of a vector of specialized replacement cost wage estimates for different child care activities rather than a single wage, and adjustments for the ratio of children to adults present and for the educational attainment of caregivers. Our estimates of the value of child care alone in 2004 and 2010 exceed previous estimates of the value of all non‐market household production in the U.S. The end result is an upward adjustment of Gross Domestic Product by about 43 percent compared to previous adjustments of about 26 percent.
Terms of Trade Shocks and Inflation Targeting in Emerging Market Economies
Authors: Hove Seedwell , Touna Mama Albert , Tchana Tchana Fulbert
Published: April 2015

Emerging market economies (EMEs) have persistently experienced different waves of commodity terms of trade disturbances, generating macroeconomic instabilities. The adoption of inflation targeting (IT) by many EMEs has raised questions about its relative suitability in dealing with these shocks compared with other monetary policy regimes. This paper tests the robustness of IT compared with monetary targeting and exchange rate targeting regimes in coping with commodity terms of trade shocks using the panel vector autoregressive technique. The results show that in general, IT countries respond better to commodity terms of trade shocks especially with respect to inflation and output gap. However, exchange rates are more volatile in IT countries than in exchange rate targeting countries. The results suggest that EME countries can reduce the adverse effects of commodity terms of trade fluctuations when they adopt IT, but they also need to pay attention to exchange rate movements.
Developing preceptorship through action research: part 2
Authors: Hilli Yvonne , Melender Hanna‐Leena
Published: April 2015

Clinical preception in practice plays a significant role in the education of both Registered Nurses and practical nurses. This study presents the evaluation of an interprofessional research and development project (2009–2103) on clinical preceptorship between two universities of applied sciences, two vocational institutes and four healthcare organisations in western Finland. The research question was as follows: How did the participants evaluate the process and outcomes of developing preceptorship through an action‐research approach? The primary target group consisted of professionals within the healthcare sector and nursing teachers at the universities of applied sciences and the vocational institutes. The five units represented in the healthcare organisations functioned as clinical practice placements for both nursing and practical nursing students, with Registered Nurses and practical nurses acting as their preceptors. Each unit developed a unique preceptorship model to answer their specific needs. The models were implemented and tested during one academic year followed by a quantitative (a 4‐point scale) and qualitative evaluation of the process. The models are presented in another article, and the evaluation results are presented in this article. The evaluation showed that preceptorship has become an important and accepted part of work, including the practice of starting any preception at a unit with a thorough introduction. The project's emphasis on critical thinking, reflection and focus on ethics were valued by the staff. Pedagogical further education should be arranged on a regular basis to strengthen the knowledge base of the preceptors. Furthermore, enough time for preceptorship should be allocated, as it is a pedagogical duty. The implication of this project is that more cooperation between different stake holders is needed, in order to narrow the gap between theory and praxis.
Association Between Suicidal Ideation and Exposure to Suicide in Social Relationships Among Family, Friend, and Acquaintance Survivors in South Korea
Authors: Song In Han , Kwon Se Won , Kim Ji Eun
Published: April 2015

Exposure to suicide in social relationships may be associated with suicidal ideation among survivors. In South Korea, which is known for having the highest suicide rate among OECD countries, exposure to suicide in social relationships can have serious consequences as social relationships are greatly emphasized in the society. The purpose of this study was to examine the association between survivors' suicidal ideation and their exposure to suicide in close relationships. Data collected through a telephone survey of a total of 1,000 men and women selected from across the nation using a stratified sampling method were analyzed. The results show that individuals who lost a family member, friend, or acquaintance in their lifetime are 4.5 times, 3.7 times, 2.2 times, respectively, more likely to have suicidal ideation in the past year compared to those without such experience. These findings suggest that special intervention for suicide survivors should be considered for those who experience suicide in close relationships.
Socialization in the Context of Risk and Psychopathology: Maternal Emotion Socialization in Children of Incarcerated Mothers
Authors: Zeman Janice , Dallaire Danielle , Borowski Sarah
Published: April 2015

Children of incarcerated mothers are at increased risk for psychological, social, and emotional maladaptation. This research investigates whether perceived maternal socialization of sadness and anger may moderate these outcomes in a sample of 154 children (53.9 percent boys, 61.7 percent Black, M age = 9.38, range: 6–12), their 118 mothers (64.1 percent Black), and 118 caregivers (74.8 percent female, 61.9 percent grandparents, 63.2 percent Black). Using mother, caregiver, and child report, seven maternal socialization strategies were assessed in their interaction with incarceration‐specific risk experiences predicting children's adjustment. For sadness socialization, the results indicated that among children reporting maternal emotion‐focused responses, incarceration‐specific risk predicted increases in psychological problems, depressive symptoms, increased emotional lability, and poorer emotion regulation. For children who perceived a problem‐focused response, incarceration‐specific risk did not predict outcomes. There were no significant interactions with incarceration‐specific risk and perceived maternal anger socialization strategies. These results indicate a critical need to examine how socialization processes may operate differently for children raised in atypical socializing contexts.
Critical Olsen P and CaCl2‐P levels as related to soil properties: results from micropot experiments
Authors: Sánchez‐Alcalá I. , del Campillo M. C. , Torrent J.
Published: April 2015

The usefulness of soil phosphorus (P) tests used in routine soil analyses is limited by the fact that a single measurement cannot encompass all P‐related factors potentially affecting plant performance. In this work, we performed micropot (15 mL) experiments to test the hypothesis that the predictive value of two common soil P tests (Olsen P and CaCl2‐P) can be improved by considering properties commonly measured in laboratory analyses. Forty‐nine sets of soils ranging widely in properties were used for this purpose, each set consisting of samples with similar properties but differing in P status. Ryegrass and turnip were grown in a chamber for 30 days in two separate experiments and their yields at harvest recorded. The critical Olsen P and CaCl2‐P levels, which were taken to be those corresponding to 95% asymptotic yield as calculated from data fitted to a Mitscherlich equation, were greater for turnip than for ryegrass, probably as a result of the difference in yield (49 and 160 mg dry matter/micropot on average for ryegrass and turnip, respectively) and hence in P requirements between the two species. Critical Olsen P spanned narrower ranges than critical CaCl2‐P in both crops and is therefore seemingly the more robust of the two tests. Both critical P values exhibited moderate correlations with soil properties. Thus, critical Olsen P was (a) lower in soils with a medium pH – which is consistent with the fact that the bicarbonate solution method tends to overestimate plant‐available P in strongly acid and calcareous soils; (b) positively correlated with pH and carbonate content in calcareous soils; and (c) uncorrelated with soil properties in noncalcareous soils. On the other hand, critical CaCl2‐P in some soil groups was negatively correlated with some properties increasing the P buffering capacity of soil (e.g. Fe oxide content). Taken together, our results suggest that routinely measured soil properties help to predict critical Olsen P better than critical CaCl2‐P.
From Empathetic Understanding to Engaged Witnessing: Encountering Trauma in the Holocaust Classroom
Authors: Gubkin Liora
Published: April 2015

A commitment to empathetic understanding shaped the field of religious studies; although subject to critique, it remains an important teaching practice where students are charged with the task of recognizing, and perhaps even appreciating, a worldview that appears significantly different from their own. However, when the focus of the course is historical trauma there are significant epistemological and ethical reasons empathetic understanding may not be our best pedagogical strategy. Drawing primarily on my experience teaching a general education class “The Holocaust and Its Impact” atCaliforniaStateUniversity,Bakersfield, I advocate replacing empathetic understanding with engaged witnessing as a pedagogical framework and strategy for teaching traumatic knowledge. To make this case, I delineate four qualities of engaged witnessing and demonstrate their use in teaching about the Holocaust.
“But Aren't Cults Bad?”: Active Learning, Productive Chaos, and Teaching New Religious Movements
Authors: Zeller Benjamin E.
Published: April 2015

This article considers the challenges inherent when teaching about new religious movements (“cults”), how successful instructors have surmounted them, and how teacher‐scholars in other fields of religious studies can benefit from a discussion of the successful teaching of new religions. I note that student‐centered pedagogies are crucial to teaching new religions, particularly if students disrupt and defamiliarize the assumed and reified categories of “cult” and “religion.” I argue that what works in a classroom focusing on new religious movements will work more broadly in religious studies classrooms, since the challenges of the former are reproduced in the latter.
Teaching the College “Nones”: Christian Privilege and the Religion Professor
Authors: Riswold Caryn D.
Published: April 2015

Working with undergraduate students invites teachers into relationship and conversation with young people at a time when they are emerging as adults and forming their identities. Faith is one area of identity formation often attended to by scholars, college professors, and their institutions. But within that, little attention has been paid to those who do not identify as religious. Additionally, “the overwhelming presence of Christianity at American institutions maintains it as the spiritual norm on campus. … Those within the spiritual norm gain a level of privilege that is often unconscious” (Seifert 2007, 11). This has an effect not only on nonreligious students but on any student who identifies as anything other than Christian; and it has a unique effect on teaching and learning in the religion classroom. In this article, I will explain what Christian privilege is, why it is a unique problem in the undergraduate religion classroom, and what teachers of religion might do in response to it. In the end,Iargue that educators need to better understand the effects of Christian privilege in our classrooms and become allies to the nonreligious in particular by using pedagogies that include and support all students, in their many religious affiliations and unaffiliations.
“Who Am I?”: The Biblical Moses as a Metaphor for Teaching
Authors: Gravett Emily O.
Published: April 2015

This essay presents Moses, the protagonist of the biblical books of Exodus and Deuteronomy in the Hebrew Bible, as a playful but generative metaphor for current teaching practices and experiences in higher education, including my own. Among numerous similarities (such as the fact that Moses, other teachers, and I are all bound by context), the most humbling insights come from Moses's role as a mediator or intermediary. It is a role that we also inhabit – standing, as it were, between our students and the knowledge of our discipline – and that we might consider further, particularly in terms of our responsibilities.
The Council of Newton: A Pedagogical Exercise for Understanding Conceptual and Historical Difference with Respect to Intra‐Religious Notions of Divinity
Authors: Karapanagiotis Nicole
Published: April 2015

In this essay, I examine the following pedagogical question: how can we unlock students' mistaken notions that religious “traditions” are monoliths, and instead help them to recognize, puzzle over, and appreciate the complex multiplicity and vibrant set of doctrinal and ritual conversations that characterize religious traditions? More specifically, how can we teach students to recognize these differences with respect to a religion's notions of god? And how can we do so even when students are particularly stuck on, invested in, or trained to see homogeneity? In answer to these questions, I present an exercise that I have used in my World Religions courses. This exercise – which I call the “Council of Newton” (named for the building in which I first taught it) – is particularly effective because it helps students uncover and wrestle with this diversity at two levels: conceptually and historically.
Phytochemical characterization and evaluation of anticataract potential of seabuckthorn leaf extract
Authors: Dubey Suchita , Deep Prakash , Singh Amrit K.
Published: April 2015

Objective

This study was undertaken to carry out phytochemical characterization of aqueous extract of Seabuckthorn (SBT, Hippophae rhamnoides L.) leaves and evaluation of its therapeutic role in oxidative stress‐induced cataract in isolated goat lenses using Vit. E as reference compound.

Animal studied

A total of 42 goat eye lenses were used in the present study.

Procedure

Seabuckthorn leaf extract was characterized by total phenol content estimation and HPLC analysis of quercetin and catechin. Further, cataract was induced in goat lenses using hydrogen peroxide (H2O2) and anticataract activity was evaluated using the extract in the dose range of 100, 200, 500, and 1000 μg/mL concentrations through estimation of biochemical markers such as superoxide dismutase (SOD), reduced glutathione (GSH), and malonaldehyde (MDA).

Results

The results of the phytochemical characterization showed the total phenol content of the extract to be 365 mg/g in terms of gallic acid equivalents. Quercetin and catechin were estimated to be 0.01 and 0.12% w/w, respectively. In biochemical analysis, H2O2 introduction resulted in a decrease in SOD (approximately 85%) and GSH (approximately 63%) contents and an increase in MDA content (approximately 300%). The decreased levels of SOD and GSH were significantly restored in experimental groups receiving 500 and 1000 1g/mL of SBT extract. All the experimental groups showed significantly reduced MDA level in all the doses.

Conclusion

Aqueous extract of SBT leaves showed the potential to delay onset and/or progression of cataract, at least during in vitro conditions. Results indicate the possibilities of evaluating this extract for its use as anticataract agent during in vivo conditions.
Third eyelid gland neoplasms of dogs and cats: a retrospective histopathologic study of 145 cases
Authors: Dees D. Dustin , Schobert Charles S. , Dubielzig Richard R. , Stein Timothy J.
Published: April 2015

Purpose

To describe the various types of primary neoplasms affecting the third eyelid (TEL) gland of dogs and cats.

Methods

A retrospective search of the Comparative Ocular Pathology Laboratory of Wisconsin (COPLOW) database was performed. Veterinary ophthalmologists, primary care veterinarians, and, when appropriate, owners were contacted for patient follow‐up information. Patient data points collected included species, age, sex, breed, laterality, tumor type, surgical margins, recurrence, metastasis, and length of follow‐up.

Results

A total of 127 canine and 18 feline cases met the inclusion criteria. The most common canineTELgland tumor was adenocarcinoma (n = 108; 85.0%) followed by adenoma (n = 18; 14.2%) and squamous cell carcinoma (SCC) (n = 1; 0.8%). For canine cases with follow‐up information available (n = 62), 8.1% had confirmed or suspected metastasis and 11.3% had confirmed or suspected local recurrence of disease. The most common felineTELgland tumor was adenocarcinoma (n = 15; 83.3%) followed bySCC(n = 3; 16.7%). For feline cases with follow‐up information available (n = 9), 40.0% had confirmed or suspected metastasis and 30.0% had confirmed or suspected local recurrence of disease.

Conclusions

This study determined that adenocarcinoma was the most common third eyelid gland tumor in both dogs and cats. The overall survival times were less, and metastatic occurrence and recurrence rates appeared to be higher for feline tumors as compared to those diagnosed in dogs. This is the first report ofSCCoriginating from glandular ductular epithelium.
Systematic review of electronic remote blood issue
Authors: Sellen K. M. , Jovanovic A. , Perrier L. , Chignell M.
Published: April 2015

Background and Objectives

The implementation of electronic remote blood issue (ERBI) may provide safety and efficiency gains for transfusion medicine. This systematic review's objective was to assess whetherERBIaffects incidents of adverse events, time taken for blood issue and delivery, and cross‐match to transfusion ratios, among other measures of safety and efficiency. The review also sought to uncover barriers and facilitators ofERBIimplementation.

Materials and Methods

We searched four aggregated electronic databases (Medline,EMBASE,CINAHLandBIOSIS) up to 19July 2012, with an updated search performed on 5March 2014 for studies onERBI. No specific study design criteria were used in the initial inclusion due to the low number of studies onERBI.

Results

A total of 4758 citations were initially identified; after 1844 duplicates were removed, 2612 citations were excluded on the basis of the abstract. Two reviewers evaluated a total of 302 full‐text articles independently; of these, seven citations were eligible for inclusion. An updated search and the authors' own collections confirmed an additional five citations, totalling 13 citations and six studies within these.

Conclusion

There is insufficient evidence to demonstrate whetherERBIsignificantly impacts safety and efficiency of blood transfusion and delivery processes. Rigorously designed studies to assess safety and efficiency outcomes are required using proxy or corollary measures. A number of positive results were reported, however, and most studies included suggestions for facilitatingERBIimplementation.
Radiofrequency Probe and Sharp Transection for Tenoscopic‐Guided Desmotomy of the Accessory Ligament of the Superficial Digital Flexor Tendon
Authors: Nelson Brad B. , Kawcak Chris E. , Ehrhart E.J. , Goodrich Laurie R.
Published: April 2015

Objective

To compare intra and postoperative clinical features of desmotomy of the accessory ligament of the superficial digital flexor tendon (ALSDFT) using the Saber radiofrequency (SaberRF) electrosurgical probe versus sharp transection with a tenotomy knife.

Study Design

Randomized, controlled, blocked (horse) design.

Animals

Adult horses (n = 6).

Methods

Each horse received bilateral, tenoscopic‐guided ALSDFT desmotomy with a SaberRF and tenotomy knife, randomly assigned to left, or right limb. The desmotomy duration and intraoperative hemorrhage grades were recorded. Postoperatively, the grades for surgical incision, carpal sheath effusion, carpal range of motion, flexion pain, and lameness were recorded. Light microscopy using hematoxylin and eosin, and viability staining were performed on the ALSDFT, flexor carpi radialis tendon, radial head of the deep digital flexor tendon, and the deep digital flexor tendon. Variables were compared between desmotomy methods with a paired t‐test, Wilcoxon signed rank test, or a repeated measures mixed model. Statistical significance was set at P < .05.

Results

Desmotomy of the ALSDFT was completed in all horses. Only mild hemorrhage was observed and not different between methods (SaberRF 2/5 limbs; tenotomy knife 5/6 limbs, P = .078). Carpal sheath effusion was greater for SaberRF at Day 1 (P = .019) but not different from tenotomy knife at any later time. There was no significant difference between methods for viability staining or other measured outcomes.

Conclusions

Tenoscopic‐guided ALSDFT desmotomy with the SaberRF probe showed no difference in measured outcomes to sharp transection with a tenotomy knife and minimal collateral tissue damage was observed.
Molecular phylogeny and divergence time estimation of Cosmodela (Coleoptera: Carabidae: Cicindelinae) tiger beetle species from Southeast Asia
Authors: López‐López Alejandro , Abdul Aziz Azidah , Galián José
Published: April 2015

Cosmodela Rivalier, 1961, represents a genus of tiger beetles that currently contains 13 described species widely distributed across Southeast Asia. A phylogenetic analysis based on the mitochondrial DNA fragments 16S and COI and the nuclear marker wingless and a phylogeographic analysis using a COI fragment were carried out on two subspecies of Cosmodela aurulenta (C. a. juxtata and C. a. aurulenta). The results support the hypothesis that these two subspecies are significantly different to be considered as separate species that diverged during the Pleistocene. TAXONDNA analysis was used to investigate the capability of the COI region as a marker for discriminating both entities and to quantify intra‐ and intertaxa genetic variation. The minimum distance between C. aurulenta and C. juxtata was 2.7837%, and no overlap of intra‐ and intertaxa genetic divergence was observed. Both taxa, here considered as valid species, occur in sympatry in the Malay Peninsula, with C. aurulenta most probably originating from the area and C. juxtata a secondary colonizer that expanded southwards from the Asian mainland. Our data infer a continental origin of the Indonesian samples of C. aurulenta, and they most likely dispersed across the land bridges that emerged during glacial maxima to form Sundaland.
Implementation Approaches to Sequencing in Microprocessor-Based Controllers
Authors: Sreetharan M. , Langenbacher F.
Published: April 2015

Traditional relay-based sequencing is increasingly being replaced by microprocessor-based programmable sequence controllers.

Microprocessor-based sequencers are flexible, easy to use and eliminate the expensive reworking of hardwired logic each time a sequencing scheme is revised. However, the logical (bit-oriented) nature of the computations involved in implementing sequencing systems offer considerable challenge to the designers of microprocessor-based (byte/word oriented) sequencers to provide novel software and/or hardware architectures that are cost effective to implement and meet the speed requirements.

This paper examines several possible implementation techniques of automatic digital sequencers. In particular, it describes the requirements and the design concepts that formed the basis of the sequencer implemented as part of a multi-processor based full authority controller at the authors’ company, that is capable of controlling a range of turbines in various applications. A comparative study of the performances of several existing sequencing systems is also presented.
Statistical Analysis of Fracture of Silicon Nitride (RBSN) Using the Short Span Bending Technique
Authors: Lamon J.
Published: April 2015

The short-span bending technique, pionneered with rod specimens of porcelain for the separation of the respective influences of surface and volume flaw populations upon strength, was applied to reaction bonded silicon nitride, prime candidate for use in advanced gas turbine systems. General approach for the statistical analysis of brittle fracture under tensile multiaxial stress states was extended to square specimens, and used to interpret experimental results.

Surface and volume flaw populations appeared to exhibit different characteristics, and thus exert different influences upon the reliability of RBSN. Implications for the interpretation of bending tests and some important trends in the failure strength with specimen size are discussed.
The Active Magnetic Bearing Enables Optimum Control of Machine Vibrations
Authors: Habermann Helmut , Brunet Maurice
Published: April 2015

The active magnetic bearing is based on the use of forces created by a magnetic field to levitate the rotor without mechanical contact between the stationary and moving parts. A ferromagnetic ring fixed on the rotor “floats” in the magnetic field generated by the electromagnets, which are mounted as two sets of opposing pairs. The current is transmitted to the electromagnetic coils through amplifiers.

The four electromagnets control the rotor’s position in response to the signals transmitted from the sensors. The rotor is maintained in equilibrium under the control of the electromagnetic forces. Its position is determined by means of sensors which continuously monitor any displacements between rotor and stator through an electronic control system.

As in every control system, damping of the loop is provided by means of a phase advance command from one or more differenciating circuits of the position error signal.

The vibrations of the rotor and stator of a machine are generated by different forces:

- centrifugal forces due to the misalignment between the geometrical axis and the inertial axis of the rotor (unbalance),

- reaction forces due to aerodynamical forces on the rotor and stator blades.

The active magnetic bearing allows the decrease and in many cases the fully cancelling of effects of these forces i.e. the vibrations of the machine. The inertial forces can be cancelled by shifting the axis of rotation of the rotor from the geometrical axis to the inertial axis (this system is usually called automatic balancing).

The reaction forces due to aerodynamical effects can be cancelled by the creation by the magnetic bearings of forces in opposition.

The vibrations are measured on the stator by accelerometers, and the signals drive magnetic bearings which generate forces having the same amplitude but in phase opposition.

The improvement in vibrations amplitude usually ranges from 20 Db to 40 Db over a large band of frequencies.
Developing Concepts in the Rotordynamic Analysis of Aero Gas Turbines
Authors: Bellamy R. A. , Jonson C. P. , Gaffney R.
Published: April 2015

Aero engine manufacturers now use large, three dimensional, non-axisymmetric detailed finite element models of complete engines as a regular production design tool to evaluate the static and dynamic structural characteristics of new design.

These have replaced the simpler beam type models for which techniques and criteria for evaluating engine dynamics had evolved over many years.

The new tools produce an order of magnitude more information that is of better quality, but much more complicated and does not allow easy use of the old criteria for evaluation. Hence new ideas are developing and new criteria are required to answer the original question, “is this engine satisfactory from the dynamics point of view?”.

This paper identifies some of the problems raised by the capability to do a 3D analysis as a standard procedure, and discusses possible solutions.
Centrifugal Mixing in Gas and Liquid Fuelled Lean Swirl Stabilized Primary Zones
Authors: Ahmad N. T. , Andrews G. E. , Kowkabi M. , Sharif S. F.
Published: April 2015

A flat bladed axial swirler of 0.7 swirl number has been investigated in a 76 mm diameter combustor with all the combustion air passing through the swirler. Both liquid and gaseous fuels were used with eight injection points on the combustor wall just downstream of the swirler. This wall injection was aimed at the exploitation of centrifugal mixing forces acting on the burnt gas pockets at the wall to send them towards the centre and to displace higher density unburnt gas pockets to the wall and so promote mixing. For both kerosene and propane fuels there was a significant improvement in the combustion efficiency and NOX emissions compared with central fuel injection. For kerosene the NOX emissions were lower than for propane and very close to those for premixed fuel and air. However, for gas oil there was little improvement in performance with wall injection compared with central. This was attributed to the slower vaporisation rate with gas oil coupled with the centrifugal action on the liquid droplets with central injection.
A Hybrid Diffuser With Distorted Inflow
Authors: Adkins R. C. , Montazerin N.
Published: April 2015

Tests have been conducted on a Conical Hybrid Diffuser of short length in order to determine the effects of a range of inlet flow distortions of an axisymmetric nature.

As with most other types of diffuser, the performance was impaired as the level of distortion was increased, although some restoration could be obtained by either increasing diffuser length or rate of bleed-off.

In general, diffuser performance, in terms of flow stability and pressure recovery, was satisfactory.
The Progress of Aero-Derivative Gas Turbines for Ground Usage in China
Authors: Yao-Xi Zhang
Published: April 2015

The development and progress of aero-derivative gas turbines for ground usage in China is reviewed. Several models derived and models in development are mentioned. as a result of some feasibility studies the prospect for future gas turbine applications is also pointed out.
A United Theory of Hybrid Problems for Fully 3-D Incompressible Rotor-Flow Based on Variational Principles With Variable Domain
Authors: Gaolian Liu
Published: April 2015

Making use of functional variations with variable domain and natural boundary conditions, this paper presents a unified theory of various hybrid problems (being a unification as well as a generalization of direct- & inverse problems) for 3-D incompressible potential flow in a rotor-blading. Three families of variational principles (VPs) have been established and provide a series of new rational ways for blade design and a sound theoretical basis for the finite element method (FEM). This theory can be extended to compressible and rotational flows and also constitutes an important part of the optimum design theory of bladings (8).
A New Theory to Solve Turbulent Vortices in Flowing Fluids
Authors: Gao Ge , Ning Huang
Published: April 2015

Turbulent vortices occur everywhere in flowing fluids and possess the properties of dissipation and dispersion. A set of new control equations is presented featuring the interaction between dissipation and dispersion of turbulence. By analysis of instability the rate of turbulent energy production is established. Two 3rd order derivative momentum equations are derived, one for weak and the other for strong vorticity. By this new theory various turbulent flow problems can be solved such as: energy inversion in the vortex tail behind a bluff body, the coherent horseshoe vortices in a turbulent boundary layer, the delay in cascading down of turbulent energy through the spectrum, anisotropy of turbulence intensities, etc. Two computational examples are presented.
Design and Development Test of a Gas Turbine Combustor for Air-Blown Lurgi Coal Gas Fuel
Authors: Beebe K. W. , Jian-Ye Li , Dao-Gang Yang , Tian-Yu Zhou
Published: April 2015

A heavy-duty industrial gas turbine combustion system has been designed and laboratory tested for use with low heating value coal gas produced by an air-blown Lurgi coal gasifier. The design fuel has a nominal lower heating value of 4.21 MJ/ncm (107 Btu/scf). The combustor design utilizes high-swirl fuel and air injection to provide rapid fuel/air mixing and a stable flame front, and is physically interchangeable with the conventional fuel combustion system for the General Electric model MS5001 gas turbine. Full-pressure, full-scale tests of the new combustion system have been conducted at the General Electric Gas Turbine Development Laboratory in Schenectady, New York, USA, for the Shanghai Power Plant Equipment Research Institute (SPPERI) of the Peoples Republic of China. Simulated clean low heating value coal gas fuel with a composition specified by SPPERI was used for these tests. Laboratory test results are presented for important combustor operating parameters, including exhaust emissions, combustion efficiency, exhaust temperature profile, dynamic pressure, and metal temperature distribution.
A Low-Expansion Superalloy for Gas-Turbine Applications
Authors: Smith D. F. , Tillack D. J. , McGrath J. P.
Published: April 2015

A high-strength, low-expansion alloy can greatly increase the efficiency of gas turbines by permitting decreased clearances between rotating and stationary parts. This paper describes development work on a series of nickel-iron-cobalt alloys having the desired combination of high strength and low thermal expansion. The first attempts to develop alloys of this type resulted in materials that required extensive thermomechanical processing and were susceptible to the phenomenon of stress-accelerated grain-boundary oxygen embrittlement (SAGBO). Further development resulted in INCOLOY alloy 909, the first low-expansion superalloy combining good resistance to SAGBO with high mechanical properties achieved without restrictive thermomechanical processing. Those substantial improvements were brought about by the addition of 0.3% to 0.6% silicon to a low-aluminum, 38% nickel, 13% cobalt, 1.5% titanium, 4.7% niobium (columbium), balance iron composition.
The Effect of Inlet Air Vitiation on Combustion Efficiency
Authors: Zuomin Fan , Yijun Jiang
Published: April 2015

Experimental results of the effect of inlet air vitiation produced by a vitiating preheater on combustion efficiency of a turbojet combustor and a model ramjet combustor are presented in this paper. An empirical correlation and a calculation method based on stirred reactor theory are derived to correct the vitiation effect. Results obtained by means of these two methods are in good agreement with test data.
Combustion of Kerosene-Water Emulsions in a Gas Turbine Combustor
Authors: Zhang Zhiren , Gollahalli S. R.
Published: April 2015

This paper describes an experimental study of the flame structure inside a combustor can of a gas turbine engine which was fueled with pure kerosene and kerosene-water emulsions. The effects of water content (5 and 10% by volume) in its emulsion with kerosene stabilized by the addition of a small amount of chemical surfactant (1% by volume) on the flame stability, temperature profiles, flame radiation, and the concentration profiles of CO, NO, NOx, O2, and soot have been studied. The results demonstrate that emulsification of kerosene with water decreases the emissions of NO, NOx, and soot and increases the emission of CO.
The Effect of Radius Change on Two-Dimensional Cascade Solutions
Authors: Caspar Joseph R. , Hobbs David E.
Published: April 2015

The effects of varying radius along a streamsurface are included in a two dimensional blade-to-blade potential flow analysis of turbomachinery rotors and stators in order to model better three dimensional effects. On a cylindrical streamsurface, flows in rotors can be treated as steady flows in the rotating frame; the rotation can be ignored. On a streamsurface with varying radius, however, the flow, even in the rotating frame, is not potential. Thus the physical flow is related to a non-physical, potential flow for calculation purposes. Computed results for compressor stators and rotors show that the potential solution agrees well with an Euler solution, that effects of radius variation are very important for both stators and rotors, and that effects of radius contouring and of rotation can also be important.
Evaluation of Ceramics for Passenger Car Turbochargers
Authors: Lasker M. F. , Craig R. P. , Mason J. L.
Published: April 2015

Structural ceramics have been proposed for gas turbines and turbochargers, and there is worldwide interest and activity aimed at developing and evaluating ceramics for these applications. This paper describes a currently active program for evaluation of ceramics for passenger car turbochargers. Results to date are encouraging and indicate that continued evaluation is desirable.
Diagnostic Procedures for Jet Engines
Authors: Lunderstädt R. , Fiedler K.
Published: April 2015

In the paper to be presented diagnostic procedures on the basis of a gas path analysis are applied on a two-shaft jet engine. Starting from the mathematical model of the engine a filter-algorithm is used which delivers from actual measurement data the state of the engine for different working conditions. The procedure is proven for some examples and discussed in regard of its practical significance.
Application of Aero-Derivative Gas Turbines in the Onshore Oil Fields of Abu Dhabi
Authors: Saadawi H.
Published: April 2015

For more than a decade, aircraft-derivative industrial gas turbines have been used in middle eastern oil fields for providing power to water injection and crude oil pumping installations.

The remote desert locations and the hostile environment provide a unique challenge. This paper describes some of the experiences gained in operating aero-derivative gas turbines in the onshore oil fields of Abu Dhabi.
Protective Coating Systems for High Temperature Gas Turbine Components
Authors: Harry N. J. F. V.
Published: April 2015

The current generation of hot end turbine blade materials and coatings for Tyne RMIC and Olympus TM3B perform most satisfactorily under normal conditions of service. In general the overall picture is optimistic and the Royal Navy does not consider there is any fundamental requirement to upgrade these systems. With the introduction of the Spey SMIA into Fleet service and the current uprating programme for the 18MW SMIC, the need for materials research has not diminished. Both of these engines are designed for long life so the search continues for blade materials and coatings which will give enhanced creep life and corrosion resistance.

This paper looks at the performance of turbine blade materials and coatings in service and reports on early experience with SM1A.
The Importance of Circumferential Non-Uniformities in a Passage-Averaged Quasi-Three-Dimensional Turbomachinery Design System
Authors: Jennions I. K. , Stow P.
Published: April 2015

The purpose of this paper is to show, for both rotating and non-rotating blade rows, the importance of including circumferential non-uniform flow effects in a quasi-three-dimensional blade design system. The paper follows on from previous publications on the system in which the mathematical analysis and computerised system are detailed. Results are presented for a different stack of the nozzle guide vane presented previously and for a turbine rotor. In the former case it is again found that the blade force represents a major contribution to the radial pressure gradient, while for the rotor the radial pressure gradient it is dominated by centrifugal effects. In both examples the effects of circumferential non-uniformities are detailed and discussed.
Improvement of a Cycle J Integral for CT-Specimens
Authors: Shao-Lun Liu , Ji-Zhou Xie
Published: April 2015

The cycle J integral formula for CT-specimens has been improved as follows

Δ J = 2 B b a 1 • U + a 2 • Δ δ + 2 B b U e { -1.2025 a w + 0.6233 0.3 ⩽ a w ⩽ 0.53 -0.02 Sin ⁡ π 0.23 a w - 0.53 0.53 < a w < 0.95

This formula is applicable to the fatigue crack propagation range of 0.3 ≤a/w<0.95. In comparision with other formulae of cycle J integral, the application range of the above expression is enlarged and its precision is also increased to a certain extent.
Lip Separate Flow Blowing and Analysis of Coherence of Inlet
Authors: Zhongwei He , Shiying Zhang
Published: April 2015

It is found in the experiments that blowing at the lip separation of the inlet obviously reduces the turbulences at the inlet exit, and apparently reduces the intensity of pressure fluctuations caused by the shock-boundary layer interaction down-stream of throat. The coherence between pressure in the interaction region and total pressure at the exit is also reduced.

The coherence between the pressure in the lip separation region and total pressure at the exit is 0.32. If, in addition, there is a stronger shock down-stream of the throat the above mentioned coherence is reduced to 0.06.
The Three-Dimensional Finite Element Cyclic Symmetric Stress Analysis for Radial Flow Impellers
Authors: Zeyong Yin , Jing Yin , Peizheng Ren , Xiaoping Zhao
Published: April 2015

This paper proposed a three-dimensional finite element stress analysis technique for radial flow impellers which has the following characteristics: utilizing the cyclic symmetry of geometry, load, and boundary condition of an impeller; and modelling an impeller in a realistic manner. The detailed stress analyses for four impellers have been carried out using the program TDSAI based on the technique. Here the analysis for one of them with curved blades is described. The finite element results for the impeller and another straight-radial-bladed impeller are compared with the photo-elastic results for the same impellers.
An Investigation of a Highly-Loaded Transonic Turbine Stage With Compound Leaned Vanes
Authors: Jing Shi , Jianyuan Han , Shiying Zhou , Mingfu Zhu , Yaoko Zhang , Mengyu She
Published: April 2015

An investigation was made to compare the performance of a highly-loaded transonic turbine stage with and without compound leaned vanes. In both cases, velocity distribution along the vane surfaces was calculated from a full 3 D time-marching finite volume method. Nozzles were tested in a wind tunnel. Through rig test, velocity profile at the stage exit was measured and the stage overall performance obtained. Performance in both tip and hub regions was improved by using the compound leaned vanes so that the stage efficiency increased by 1% approximately. The improvement is payticylarly remarkable at off-design points.
Rapid Calculation of Engine Performance
Authors: Jin Zhang , Xinjian Zhu
Published: April 2015

A rapid calculation procedure for design and off-design performance of turbojet and turbofan engine is developed. It peculiarity is that the general characteristics of components are established based on statistical data and the engine working conditions are searched according to matching of these general characteristics. This method can be used to select cycle parameters in engine design, and has been employed in engine performance calculation program used in the preliminary phase of engine design or airframe/engine integration design.
Hot-Pressed Silicon Nitride Ceramics With Rare-Earth Oxides Additives
Authors: Youren Xu , Liping Huang , Xiren Fu , Tungsheng Yen
Published: April 2015

A hot-pressed silicon nitride ceramic material with rare-earth oxides additive has been processed, its bend strength maintains 800–900 MPa up to 1300°C and measures 680 MPa at 1400°C, its fracture toughness at room temperature is 4.38–4.96 MPam. X-ray, SEM, EDS and electron probe analyses reveal that the microstructure of this material is composed of fine β-Si3N4 grains, α-Si3N4 whiskers, small tetragonal lanthanide crystals and La-containing glassy phase. Observation on fracture surface shows that the fracture path is mainly transcrystalline up to 1400°C. The effects of additives on strength and fracture toughness of HPSN obtained are also discussed.
Experimental Research of the Secondary Flow in Rectilinear Turbine Cascades
Authors: Da-Jun Ye , Li-Wei Zhou
Published: April 2015

For studying the secondary flow in a turbine cascade, the flow field is measured in detail. The measurements of pressure and velocity are taken at various axial planes upstream of, within, and downstream of the cascade by a 4-hole probe. The static pressures are taken on the endwall, suction and pressure surfaces. By treating the experiment data the mechanism of the secondary flow field and the loss model are proposed in this paper.
Modelling of Component Faults and Application to On-Condition Health Monitoring
Authors: Dupuis R. J. , Saravanamuttoo H. I. H. , Rudnitski D. M.
Published: April 2015

Fault matrices can be predicted for any gas turbine, making use of well established component matching techniques and corrections for component deterioration. Quantification of deterioration levels is difficult and more than one component may be subject to in-service deterioration. Computer models of a twin-spool gas generator have been used to predict the effects of varying levels of component performance loss, and these are used to evaluate fault matrices for use with engines in the field.
A Design Time Marching Method for the Generation of Blades in a Cascade
Authors: Singh U. K.
Published: April 2015

A time marching method is described which generates the blade profiles in a cascade corresponding to a prescribed pressure distribution (with or without shock waves) around the blade surfaces. The method can be used either to generate entire blade shapes or to modify regions of suction and pressure surfaces. The method enables a reduction in overall aerodynamic design time.
Toward Improved Durability in Advanced Combustors and Turbines — Progress in the Prediction of Thermomechanical Loads
Authors: Sokolowski Daniel E. , Ensign C. Robert
Published: April 2015

NASA is sponsoring the Turbine Engine Hot Section Technology (HOST) Project to address the need for improved durability in advanced combustors and turbines. Analytical and experimental activities aimed at more accurate prediction of the aerothermal environment, the thermomechanical loads, the material behavior and structural responses to such loading, and life predictions for high temperature cyclic operation have been underway for several years and are showing promising results. Progress is reported in the development of advanced instrumentation and in the improvement of combustor aerothermal and turbine heat transfer models that will lead to more accurate prediction of thermomechanical loads.
Reducing Turbo Machinery Operating Costs With Regular Performance Testing
Authors: Scott J. N.
Published: April 2015

With the high price of fuel and diminishing supplies it is necessary to maintain the efficiency and optimize the use of turbo machinery equipment. Operating practices and maintenance procedures that were acceptable several years ago can no longer be tolerated because they are wasteful of fuel. Regular performance testing will highlight inefficient equipment and could give warning of impending failures.