bluuebunny/crossref_metadata_2025 huggingface dataset:
The Anthropology of Christianity
Authors: Bialecki Jon , Haynes Naomi , Robbins Joel
Published: November 2008

This article surveys the literature that constitutes the newly emergent anthropology of Christianity. Arguing that the development of this sub‐discipline was impeded until recently by anthropology's theoretical framing and empirical interests, this article explains that demographic and world‐historical forces have made it such that anthropology has had to recently come to terms with Christianity as an ethnographic object. In doing so, anthropology also has had to address its problematic relationship with Christianity, either in the religion's direct effect on the formation of the discipline, or as reflected by Christianity's influence on modernity itself, which has been vital for anthropology as both a category and as a style of cognition. In addition to these meta‐theoretical questions, the anthropology of Christianity has become a space in which anthropology has been able to re‐examine issues of social and cultural continuity and discontinuity in light of conversion to Christianity. Specifically, the issue of social change (often thought through or against the issue of ‘modernity’) has involved specific ethnographic examinations of fields, such as the relation between linguistic ideology and language use, economic practice, changing formations of gender and race, and the modes through which the person is culturally structured, and how that category of the person stands in relation to the social. Rather than presenting an overarching theoretical narrative, however, this review notes that these issues play out in divergent ways in differently situated communities, especially where Christianity's individuating effect may be muted where is it functions as an anti‐ or counter‐modern force; this dynamic and contingent nature of Christianity underscores that Christianity itself is a heterogeneous object, and thus promises to be an area of rich empirical research and theoretical focus that should be beneficial not only for this sub‐discipline, but also for the field of anthropology as a whole.
Operationalizing Linguistic Gratuity: From Principle to Practice
Authors: Wolfram Walt , Reaser Jeffrey , Vaughn Charlotte
Published: November 2008

Although there is a well‐established tradition of social engagement in sociolinguistics, there is little explicit discussion of the rationale, methods, and procedures for implementing the principle of linguistic gratuity. What approaches to the dissemination of sociolinguistic information must be adopted with communities and with the general public when language diversity is interpreted in terms of a prescriptive, correctionist model? What venues, activities, and products are the most effective in dialect awareness programs? And how does linguist–community collaboration work on a practical level? We consider theoretical, methodological, and practical issues in sociolinguistic engagement and dialect awareness outreach programs based on a range of experience in a variety of local and general public venues. The approach is based on the principle that the public is inherently curious about language differences and that this intrigue can be transformed into informal and formal public education. It is further premised on evidence that language differences can be linked to legitimate historical and cultural legacies, and that positively framed presentations of language differences in sociocultural and sociohistorical contexts can effectively counter dominant, seemingly unassailable ideologies in non‐confrontational ways. A variety of venues are considered in collaborative engagement, including video documentaries, oral history CDs, museum exhibits, formal curricular programs, and popular trade books on language differences. Challenges in operationalizing linguistic gratuity include working with the community; balancing community linguistic expertise and community perspectives; design and audience, and practical logistical issues.
Locutionary, Illocutionary, Perlocutionary
Authors: Kissine Mikhail
Published: November 2008

J. L. Austin's three‐prong distinction between locutionary, illocutionary and perlocutionary acts is discussed in terms of D. Davidson's theory of action. Perlocutionary acts refer to the relation between the utterance and its causal effects on the addressee. In contrast, illocutionary and locutionary acts are alternative descriptions of the utterance. The possibility of conceiving of locutionary acts as expressing propositions under a certain mode of presentation is discussed. Different ways to define illocutionary acts without encroaching on the locutionary or perlocutionary territory are considered.
Autophagy and Cell Death of Purkinje Cells Overexpressing Doppel in Ngsk Prnp‐deficient Mice
Authors: Heitz Stéphane , Grant Nancy J. , Leschiera Raphael , Haeberlé Anne‐Marie , Demais Valérie , Bombarde Guy , Bailly Yannick
Published: November 2008

In Ngsk prion protein (PrP)‐deficient mice (NP0/0), ectopic expression of PrP‐like protein Doppel (Dpl) in central neurons induces significant Purkinje cell (PC) death resulting in late‐onset ataxia. NP0/0 PC death is partly prevented by either knocking‐out the apoptotic factor BAX or overexpressing the anti‐apoptotic factor BCL‐2 suggesting that apoptosis is involved in Dpl‐induced death. In this study, Western blotting and immunohistofluorescence show that both before and during significant PC loss, the scrapie‐responsive gene 1 (Scrg1)—potentially associated with autophagy—and the autophagic markers LC3B and p62 increased in the NP0/0 PCs whereas RT‐PCR shows stable mRNA expression, suggesting that the degradation of autophagic products is impaired in NP0/0 PCs. At the ultrastructural level, autophagic‐like profiles accumulated in somatodendritic and axonal compartments of NP0/0, but not wild‐type PCs. The most robust autophagy was observed in NP0/0 PC axon compartments in the deep cerebellar nuclei suggesting that it is initiated in these axons. Our previous and present data indicate that Dpl triggers autophagy and apoptosis in NP0/0 PCs. As observed in amyloid neurodegenerative diseases, upregulation of autophagic markers as well as extensive accumulation of autophagosomes in NP0/0 PCs are likely to reflect a progressive dysfunction of autophagy that could trigger apoptotic cascades.
Emotions and the Development of Childhood Depression: Bridging the Gap
Authors: Cole Pamela M. , Luby Joan , Sullivan Margaret W.
Published: November 2008

ABSTRACT—
There is a gap between scientific knowledge about typical and atypical emotional development and efforts to identify and serve children’s mental health needs. The gap can be bridged with research that integrates clinical perspectives into the study of emotional development. This is illustrated in the current study by discussing typical emotional development in early childhood and how it differs from the atypical features of emotion seen among preschool‐aged children with depression. New research directions are suggested that integrate the study of typical emotional development with clinical evidence of risk for and presence of affective disorders in young children.
Introduction to the Special Section: The Application of Effect Sizes in Research on Children and Families
Authors: Supplee Lauren H
Published: November 2008

ABSTRACT—
Effect sizes are increasingly used to describe the magnitude of findings about program effectiveness across a range of policy contexts. However, often, both researchers and policy makers could benefit from more information about the factors that affect the calculation and interpretation of these effect sizes. To address these issues, the Administration for Children and Families and federal partners convened a roundtable in 2007, entitled Application of Effect Sizes in Research on Children and Families. This special section includes articles from this roundtable that begin a focused discussion about the purposes, calculation, and interpretation of effect sizes.
What Are Effect Sizes and Why Do We Need Them?
Authors: Hedges Larry V
Published: November 2008

ABSTRACT—
Effect sizes are quantitative indexes of the relations between variables found in research studies. They can provide a broadly understandable summary of research findings that can be used to compare different studies or summarize results across studies. Unlike statistical significance (p values), effect sizes represent strength of relationships without regard to sample size. Three families of effect sizes are widely used: the standardized mean difference family, the standardized regression coefficient family, and the odds ratio family.
Averaging Effect Sizes Within and Across Studies of Interventions Aimed at Improving Child Outcomes
Authors: Dong Nianbo , Maynard Rebecca A. , Perez‐Johnson Irma
Published: November 2008

ABSTRACT—
Scientific and political forces are moving the social services field toward greater reliance on evidence‐based interventions or strategies, including in the area of child development. This article draws on the work of meta‐analysts to illustrate how study findings can sometimes be made more accessible to policy makers and practitioners by converting them to effect sizes and averaging them within or across studies. The article first introduces the concept of an effect size. Using empirical examples, it then illustrates the mechanics of computing average effect sizes and discusses their benefits and limitations as summary measures of the estimated effects of interventions. It also provides guidance regarding when it is appropriate to pool findings across studies and how to display results to promote transparency.
Examining How Context Changes Intervention Impact: The Use of Effect Sizes in Multilevel Mixture Meta‐Analysis
Authors: Hendricks Brown C. , Wang Wei , Sandler Irwin
Published: November 2008

ABSTRACT—
In describing the impact of an intervention, a single effect size, odds ratio, or other summary measure is often employed. This single measure is useful in calibrating the effect of one intervention against others, but it is less meaningful when the intervention displays variation in impact. A single intervention trial can show differential effects when subgroups respond differentially, when impact varies by environmental context, or when there is varying impact with different outcome measures or across follow‐up time. This article presents a multilevel mixture modeling approach for meta‐analyses that summarizes these sources of impact variation across trials and measured outcomes.
Volunteerism: Social Issues Perspectives and Social Policy Implications
Authors: Snyder Mark , Omoto Allen M.
Published: November 2008

This analytic review focuses on theory and research on volunteerism. First, we define volunteerism as freely chosen helping activities that extend over time and that are often performed through organizations and on behalf of receptive causes or individuals. Next, we link these definitional features to the Volunteer Process Model, which depicts volunteerism as a process with three sequential and interactive stages (antecedents, experiences, and consequences) and at multiple levels of analysis. Then, we use this model to organize the empirical literature on volunteerism and selected work on social movements. Finally, we discuss implications for social policy issues relevant to individuals, organizations, communities, and societies.
Attachment, Perceived Support, and the Transition to Parenthood: Social Policy and Health Implications
Authors: Simpson Jeffry A. , Rholes W. Steven
Published: November 2008

For some people involved in certain relationships, the transition to parenthood is associated with precipitous declines in marital satisfaction and increases in depressive symptoms. After briefly reviewing the transition to parenthood literature, we explain why attachment theory is particularly well suited to account for how and why certain people involved in certain relationships are so vulnerable to these negative outcomes. Testing diathesis‐stress models, we present evidence from our own research indicating that more anxiously attached women who enter parenthood perceiving lower levels of spousal support or greater spousal anger are especially susceptible to experiencing significant pre‐to‐postpartum decreases in marital satisfaction and increases in depressive symptoms across the first 6 months of the transition. We also present evidence isolating some of the psychological processes that may be partially responsible for generating and sustaining these negative outcomes. We conclude by discussing how specific prevention programs, experimental interventions, or individually based therapies could be developed to buffer vulnerable people from negative postpartum outcomes.
Determinants and Consequences of Jury Racial Diversity: Empirical Findings, Implications, and Directions for Future Research
Authors: Sommers Samuel R.
Published: November 2008

One of the ideals underlying any jury system is that those groups of citizens charged with the responsibility of deciding cases should be representative of the communities from which they are selected. Anecdotal and empirical data suggest that reality often falls short of this ideal, however, as many empanelled juries are less diverse than community demographics would dictate. This article reviews the obstacles that stand in the way of jury diversity and typically, by association, jury representativeness. These range from system‐related problems regarding jury source lists and summonses to more psychological considerations such as the pervasive, yet difficult‐to‐identify impact of race on attorneys' jury selection judgments. Drawing on psychological theory and findings, the implications of the failure to empanel diverse juries are also examined, both in terms of laypeople's attitudes toward the legal system as well as the actual decision‐making performance of juries. Policy changes intended to promote diverse, representative juries are considered, as are specific directions for future research.
The Rights and Responsibilities of Gay and Lesbian Parents: Legal Developments, Psychological Research, and Policy Implications
Authors: Chamberlain Jared , Miller Monica K. , Bornstein Brian H.
Published: November 2008

With the growing number of same‐sex unions, the legal system must determine the rights and responsibilities of gay parents who decide to end a relationship. In 2005, the California Supreme Court found that a child's lesbian caregiver was a legal “parent” despite having no biological or adoptive relationship, while the Massachusetts Supreme Court in 2004 concluded the opposite. Psychologists can inform this debate by presenting research demonstrating that (a) children benefit from contact with two parents, and (b) children's well‐being is unaffected by their parents' sexual orientation. Psychologists can further assist the legal system by conducting future research. In order for psychologists to impact laws and policies, legal actors must utilize this expertise.
Creating More Effective Multiethnic Schools
Authors: Zirkel Sabrina
Published: November 2008

The empirical literature from education, psychology, and sociology is reviewed in order to identify strategies with demonstrated effectiveness in improving either the educational outcomes of students of color, interethnic relations in schools and colleges, or both. The conceptual framework for this review identifies eight core themes that can guide policy and change efforts in this area: (a) the need to explicitly and directly address issues of aversive and institutional racism, (b) the importance of conceiving of schools as agents of change, (c) the importance of leadership in setting a school or district tone, (d) the paradox that strategies for improving the educational outcomes for students of color can only be achieved by focusing on race and ethnicity, but the outcome of these efforts benefit all students, (e) the goals of improving interethnic relations and the educational outcomes of students of color are linked (in that improving one improves the other), (f) the need to explicitly affirm one's confidence in the abilities of students of color, (g) the importance of creating opportunities for the development of a strong, positive racial or ethnic identity, and (h) the need to create settings in which students feel connected to school through their relationships with peers and teachers.
New Global Politics of Reproductive Labor: Gendered Labor and Marriage Migration
Authors: Lan Pei‐Chia
Published: November 2008

The feminization of international migration nowadays has demonstrated a new global politics of reproductive labor (work necessary for the reproduction of families). This paper reviews recent studies that manifest similarity, affinity, and continuity across multiple forms of reproductive labor carried out by migrant women in four aspects. First, the recruitment of women as foreign maids or foreign brides provides class‐specific parallel strategies to the global care crisis. Second, paid and unpaid forms of reproductive labor constitute intersecting circuits of labor and marriage migration through which women partake in continuous migration. Third, various categories of migrant women are discursively conflated and attached to similar images as sexualized others. Finally, global care chains not only involve migrant reproductive labor conducted at home but also operate on the level of social reproduction as indicated by the expansion of international nursing migration.
An Assessment of Dental Treatment Need: An Overview of Available Methods and Suggestions for a New, Comparative Summative Index
Authors: Aleksejūnienė Jolanta , Brukienė Vilma
Published: November 2008

Objective: The aims were to give an overview and consider advantages and disadvantages of different approaches used to evaluate dental treatment need and to suggest an alternate Quantitative Summative Dental Treatment Need Index. Methods: The Medline Ovid database was searched for relevant articles published during the last three decades combining the terms “needs assessment,”“dental care,”“health services needs and demand.”Results: There were substantial differences in methods used. Different modifications of the Decayed, Missing, Filled Teeth/Surfaces indices, complex quantitative summative indices, or simplified approaches were used to assess dental treatment need. Differing advantages and disadvantages of these methods can be identified. Previously used approaches have a common limitation for use in oral epidemiology. Conclusions: The suggested alternate Quantitative Summative Dental Treatment Needs Index focuses on an ability to compare both the total burden of treatment need as well as to make a distinction among specific treatment needs across populations. This new approach is an attempt to develop a comprehensive index for use in oral epidemiology with further revisions anticipated.
Use of Patient Self‐Report Oral Health Outcome Measures in Assessment of Dental Treatment Outcomes
Authors: Wright Wanda G. , Jones Judith A. , Spiro III Avron , Rich Sharron E. , Kressin Nancy R.
Published: November 2008

Objective: To assess the sensitivity of a newly developed brief measure of oral health‐related quality of life (OQOL). Methods: Self‐assessed oral health and OQOL were measured in three groups of patients who had presented for either prophylaxis (n = 32), endodontic care (n = 15), or for a denture (n = 16) in a dental school setting before and after treatment. Main outcome measures included the single‐item self‐report of oral health (OH‐1) and the 6‐ and 12‐item versions of a new OQOL instrument. General linear modeling was used to compute means of self‐reported oral health by treatment group. Results: Of the 63 patients who completed the baseline questionnaire, 44 (70 percent) returned questionnaires after treatment. The sample averaged 43 ± 15 years, 48 percent male and 55 percent with some college education. Ethnic representation included 35 percent White, 33 percent Black, and 32 percent other – mostly Latino. The mean self‐reported number of teeth was 20.6. In terms of sensitivity, significant differences were observed between the treatment groups on the items assessing being upset (P < 0.05), feeling depressed (P < 0.05), and uncomfortable about the appearance of teeth or dentures (P < 0.05). However, magnitude of change, as measured by an effect size, was characterized as minimal to small in the recall and endodontic groups and borderline moderate in the denture group. Conclusion: The measure was sensitive to differences within groups, with a small to borderline magnitude of change.
Patterns and Correlates of Spit Tobacco Use among High School Males in Rural California
Authors: Gansky Stuart A. , Ellison James A. , Kavanagh Catherine , Isong Umo , Walsh Margaret M.
Published: November 2008

Objective: To assess patterns and correlates of spit [smokeless tobacco (ST)] use among high school males in rural California. Methods: An 18‐item, self‐administered questionnaire was used to assess ST use among young males in 41 randomly selected high schools in 21 rural counties in California. To ensure confidentiality, students were instructed to seal their completed questionnaire in an attached envelope prior to returning it to the questionnaire administrator. Results: Overall prevalence of ST use was 9.8 percent, significantly increasing with year in school from 5 percent among freshmen to 15 percent among seniors. ST use was highest among rodeo athletes at 42 percent compared with <6 percent among nonathletes; ST use was significantly higher among smokers (32 percent) who were 2.5‐30 times more likely to use ST compared with nonsmokers, depending on race/ethnicity as a result of a significant race/ethnicity × smoking interaction of degree/magnitude. In addition, students who believed there was no, or slight risk of, harm from ST use were significantly more likely to use ST than students perceiving moderate or great risk, depending on race/ethnicity (odds ratios 3.6‐13). Among all ST users, 40 percent used ST on at least 5 days in the previous week, 80 percent of those reporting a brand used the brand Copenhagen, and 41 percent (189) used ST within 30 minutes of waking. Conclusion: Dental public health practitioners, scholars, and policy‐makers need to promote dental health through organized community efforts targeting high school male subgroups in rural areas that are at risk for ST‐associated adverse health effects.
Effect of Side Feed Pressurization on the Dynamic Performance of Gas Foil Bearings: A Model Anchored to Test Data
Authors: Kim Tae Ho , San Andrés Luis
Published: November 2008

Comprehensive modeling of gas foil bearings (GFBs) anchored to reliable test data will enable the widespread usage of these bearings into novel high speed turbomachinery applications. GFBs often need a forced cooling gas flow, axially fed through one end of the bearing, for adequate thermal management. This paper presents rotordynamic response measurements on a rigid rotor supported on GFBs during rotor speed run-up and coastdown tests with the GFBs supplied with increasing feed gas pressures to 2.8bars. Rotor speed run-up tests to 35krpm show that the bearing end side feed gas pressurization delays the onset speed of rotor subsynchronous whirl motions. The test data validate closely the predictions of the threshold speed of instability and the whirl frequency ratio derived from a GFB model that implements the axial evolution of gas circumferential flow velocity as a function of the imposed side feed pressure. Rotor speed coastdown tests from 25krpm with a low feed pressure of 0.35bar evidence a nearly linear synchronous rotor response for small and moderately large imbalance mass distributions. A structural finite element rotordynamics model integrates linearized synchronous speed GFB force coefficients and predicts synchronous responses, amplitude, and phase angles, agreeing with the test data. The analysis and measurements demonstrate the profound effect of the end side feed gas pressurization on the rotordynamic performance of GFBs.
The Lean Mixture Operational Limits of a Spark Ignition Engine When Operated on Fuel Mixtures
Authors: Li Hailin , Karim Ghazi A. , Sohrabi A.
Published: November 2008

The operation of spark ignition (SI) engines on lean mixtures is attractive, in principle, since it can provide improved fuel economy, reduced tendency to knock, and extremely low NOx emissions. However, the associated flame propagation rates become degraded significantly and drop sharply as the operating mixture is made increasingly leaner. Consequently, there exist distinct operational lean mixture limits beyond which satisfactory engine performance cannot be maintained due to the resulting prolonged and unstable combustion processes. This paper presents experimental data obtained in a single cylinder, variable compression ratio, SI engine when operated in turn on methane, hydrogen, carbon monoxide, gasoline, iso-octane, and some of their binary mixtures. A quantitative approach for determining the operational limits of SI engines is proposed. The lean limits thus derived are compared and validated against the corresponding experimental results obtained using more traditional approaches. On this basis, the dependence of the values of the lean mixture operational limits on the composition of the fuel mixtures is investigated and discussed. The operational limit for throttled operation with methane as the fuel is also established.
Use of Turning Additional Blades in Compressor Rotor
Authors: Nezym Vitaliy Yu.
Published: November 2008

An application of tip devices in the form of turning (adjustable) tip additional blades is rather effective means of influence on compressor performance due to change of fluid conditions in the region of rotating blade tips. The paper presents main results of tests of turning tip additional blades of two types. Firstly tip elements of rotating blades were substituted for turning tip additional blades at full length of the blade chord projection. While testing of these “large” additional blades with variable stagger angles, a significant shift of rotor performance curve to lower values of flow coefficients was observed, but this positive effect was accompanied by a great rotor peak efficiency drop. Then the similar turning tip additional blades were arranged only in the inlet part of rotating blades (“short” additional blades). Testing was done under condition of variable stagger angles in common with change of axial clearance between blade elements. As a result of these two parameters combination, maximum extension of stable operating range was found. And the important fact is that the rotor efficiency drop was relatively small after sharpening the inlet edges of the succeeding elements of rotating blades.
Turbine Blade Shape Aerodynamic Design Using Artificial Intelligence
Authors: O¨ksu¨z O¨zhan , Akmandor I˙brahim Sinan
Published: November 2008

This paper describes a fast, efficient, robust, and automated design method used to aerodynamically optimize 3D gas turbine blade shapes implementing artificial intelligence. The design objectives are maximizing the aerodynamic efficiency and torque so as to reduce the weight and size and cost of the gas turbine engine. The procedure described here will allow a rapid, practical and low cost design that will answer the need of gas turbine industry. A 3-Dimensional steady Reynolds Averaged Navier Stokes solver is coupled with an automated unstructured grid generation tool. The solver is verified using two well known test cases. Blade geometry is modeled by 36 design variables plus the number of blades variable in a row. A genetic algorithm is used for global optimization purposes. One of the test cases is selected as the baseline and is modified by the design process. It was found that the efficiency can be improved from 83.9% to 85.9%, and the torque can be improved as much as 7.6%. The flow field investigations indicate enhanced secondary flow characteristics of the blade passage.
Thermal-Mechanical Life Prediction System for Anisotropic Turbine Components
Authors: Cunha F. J. , Dahmer M. T. , Chyu M. K.
Published: November 2008

Modern gas turbine engines provide large amounts of thrust and withstand severe thermal-mechanical conditions during the load and mission operations characterized by cyclic transients and long dwell times. All these operational factors can be detrimental to the service life of turbine components and need careful consideration. Engine components subject to the harshest environments are turbine high-pressure vanes and rotating blades. Therefore, it is necessary to develop a turbine component three-dimensional life prediction system, which accounts for mission transients, anisotropic material properties, and multi-axial, thermal-mechanical, strain and stress fields. This paper presents a complete life prediction approach for either commercial missions or more complex military missions, which includes evaluation of component transient metal temperatures, resolved maximum shear stresses and strains, and subsequent component life capability for fatigue and creep damage. The procedure is based on considering all of the time steps in the mission profile by developing a series of extreme points that envelop every point in the mission. Creep damage is factored into the component capability by debiting thermal-mechanical accumulated cycles using the traditional Miner’s rule for accumulated fatigue and creep damage. Application of this methodology is illustrated to the design of the NASA Energy Efficient Engine (E3) high pressure turbine blade with operational load shakedown leading to stress relaxation on the external hot surfaces and potential state of overstress in the inner cold rib regions of the airfoil.
Experimental Characterization of Film-Cooling Effectiveness Near Combustor Dilution Holes
Authors: Scrittore J. J. , Thole K. A. , Burd S. W.
Published: November 2008

Cooling combustor chambers for gas turbine engines is challenging, given the complex flow and thermal fields inherent to these modules. This complexity, in part, arises from the interaction of high-momentum dilution jets required to mix the fuel with film cooling jets that are intended to cool the combustor walls. This paper discusses the experimental results from a combustor simulator tested in a low-speed wind tunnel that includes both the dilution jets and film-cooling jets. The specific purpose of this study is to evaluate the influence that the dilution jets has on the film-cooling effectiveness. Infrared thermography was used to measure surface temperatures along a low thermal conductivity plate to quantify the adiabatic effectiveness from an array of film cooling holes with the presence of dilution holes. To further understand the flow phenomena, thermocouple probes and laser Doppler velocimetry were used to measure the thermal and flow fields, respectively. Parametric experiments indicate that the film cooling flow is disrupted along the combustor walls in the vicinity of the high-momentum dilution jets. In fact, a significant penalty in cooling effectiveness of the combustor is observed with increased dilution jet penetration.
Modeling of Film Cooling: Part II — Model for Use in 3D CFD
Authors: Burdet Andre´ , Abhari Reza S. , Rose Martin G.
Published: November 2008

Computational Fluid Dynamics (CFD) has been used recently for the simulation of the aerothermodynamics of film cooling. The direct calculation of a single cooling hole requires substantial computational resources. A parametric study, for the optimization of the cooling system in real engines, is much too time consuming due to the large number of grid nodes required to cover all injection holes and plenum chambers. For these reasons a hybrid approach is proposed, based on the modeling of the near film-cooling hole flow, tuned using experimental data, while computing directly the flow field in the blade-to-blade passage. A new injection film-cooling model is established, which can be embedded in a CFD code, to lower the Central Processing Unit (CPU) costs and reduce the simulation turnover time. The goal is to be able to simulate film-cooled turbine blades without having to explicitly mesh the holes with the plenum chamber. The stability, low CPU overhead level (1%) and accuracy of the proposed CFD-embedded film-cooling model, are demonstrated in the ETHZ steady film-cooled flat plate experiment [5] presented in Part I of this two-part paper. The prediction of film-cooling effectiveness using the CFD-embedded model is evaluated.
Development of a Semi-Implicit Solver for Detailed Chemistry in I.C. Engine Simulations
Authors: Liang Long , Jung Chulhwa , Kong Song-Charng , Reitz Rolf D.
Published: November 2008

An efficient semi-implicit numerical method is developed for solving the detailed chemical kinetic source terms in I.C. engine simulations. The detailed chemistry system is a group of coupled extremely stiff O.D.E.s, which presents a very stringent timestep limitation when solved by standard explicit methods, and is computationally expensive when solved by iterative implicit methods. The present numerical solver uses a stiffly-stable noniterative semi-implicit method, in which the numerical solution to the stiff O.D.E.s never blows up for arbitrary large timestep. The formulation of numerical integration exploits the physical requirement that the species density and specific internal energy in the computational cells must be nonnegative, so that the Lipschitz timestep constraint is not present [1,2], and the computation timestep can be orders of magnitude larger than that possible in standard explicit methods and can be formulated to be of high formal order of accuracy. The solver exploits the characteristics of the stiffness of the O.D.E.s by using a sequential sort algorithm that ranks an approximation to the dominant eigenvalues of the system to achieve maximum accuracy. Subcycling within the chemistry solver routine is applied for each computational cell in engine simulations, where the subcycle timestep is dynamically determined by monitoring the rate of change of concentration of key species which have short characteristic time scales and are also important to the chemical heat release. The chemistry solver is applied in the KIVA-3V code to diesel engine simulations. Results are compared with those using the CHEMKIN package which uses the VODE implicit solver. Very good agreement was achieved for a wide range of engine operating conditions, and 40∼70% CPU time savings were achieved by the present solver compared to CHEMKIN.
An Experimental and Numerical Investigation on the Effect of Post Injection Strategies on Combustion and Emissions in the Low-Temperature Diesel Combustion Regime
Authors: Yun Hanho , Sun Yong , Reitz Rolf D.
Published: November 2008

In order to meet future emissions regulations, new combustion concepts are being developed. Among them, the development of low-temperature diesel combustion systems has received considerable attention. Low NOx emissions are achieved through minimization of peak temperatures occurring during the combustion process. Concurrently, soot formation is inhibited due to a combination of low combustion temperatures and extensive fuel-air pre-mixing. In this study, the effect of late-cycle mixing enhancement by post injection strategies on combustion and engine-out emissions in the low-temperature combustion regime was investigated experimentally and numerically. The baseline operating condition considered for low-temperature combustion was 1500 rev/min, 3bar IMEP with 50% EGR rate, and extension to high loads was considered by means of post injection. Post injection strategies gave very favorable emission results in the low temperature combustion regime at all loads. With small second fuel injected amounts, better soot emissions were found. However, the determination of the dwell between the injections was found to be very important for the emissions. Since post injection leads to late-cycle mixing improvement, further reductions in soot emissions were achieved without deteriorating the NOx emissions. To explain these results, numerical analysis was also done using the KIVA-CHEMKIN code. The simulations show that optimal combustion requires that the post injection fuel avoid fuel rich regions formed from the main injection.
Cooling Challenges of Modern Truck Diesel Engines
Authors: Bowman John P. , Krishnan Sivakumar S. , Nalim Razi
Published: November 2008

Efficient cooling system designs are required for the modern diesel truck engine to meet new standards of increased efficiency and reduced emissions. Often, emissions reduction requires substantial cooled exhaust gas recirculation (EGR) to decrease peak combustion temperatures. This extra heat rejection imposes additional costs on the cooling system, and may not comply with application space constraints. Space and cost constraints require minimization of EGR cooler size and the risks from coolant boiling and exhaust condensation, while restraining growth in radiator frontal area, pumping power, and fan power. These objectives are usually contradictory, and a careful optimization is needed. This paper examines the effect of a coolant flow rate and peak temperature on these objectives, in parallel-flow and counter-flow arrangements of EGR cooler systems. It is concluded that these systems are likely to be inadequate, and alternative configurations may be necessary.
Plasma Resource Recovery Technology: Converting Waste to Energy and Valuable Products
Authors: Carabin Pierre , Holcroft Gillian
Published: November 2008

Plasma Resource Recovery (PRR) is a revolutionary technology that can treat virtually any type of waste by combining gasification with vitrification. Vitrification produces inert slag that can be used as a construction material. Gasification produces a fuel gas containing carbon monoxide (CO) and hydrogen (H2), used for cogeneration of electricity and steam. The plasma fired eductor which is the core technology of the PRR system is presently being used commercially on a cruise ship at a scale of 5 TPD. The capabilities of the PRR technology have been demonstrated in a pilot plant, at a rate of up to 2 TPD of various types of waste. Because of the high intensity of the plasma flame and the reduced amounts of gases produced in a gasification system, compared to traditional combustion systems, the PRR system is typically very compact. As such, the PRR technology opens the door for a decentralized, small scale approach to waste management.
Modelling of Offshore Tubular Members in Non-Linear Analyses
Authors: Skinner Ken , Styles David W. , Yasseri Sirous F.
Published: November 2008

This paper presents results of a study into calibrating beam elements properties for use in non-linear finite element analyses, such that the elements simulate the behaviour of real members. Following the API approach, it is recommended that the material strength is de-rated to achieve a well-behaved element. A large number of typical “imperfect” offshore tubular members were modelled using shell elements and analysed to determine the full range of their load-displacement behaviour. The complete practical range of combination of the slenderness and D/t (diameter to thickness) ratios were considered. Then the beam elements’ material was de-rated to achieve the same results as obtained from the shell model. The result of the study is a two-way table which gives the required de-rating as a function of the slenderness ratio and the D/t ratio.
Significance of HAZ Softening on Strain Concentration and Crack Driving Force in Pipeline Girth Welds
Authors: Liu Ming , Wang Yong-Yi , Horsley David
Published: November 2008

Modern micro-alloyed, control-rolled TMCP steels generally have good strength, high toughness, and good weldability. However, these valuable properties come along with certain undesirable features, such as low strain hardening (high yield to tensile ratio), low ductility as measured by uniform elongation (elongation at ultimate tensile strength), and possible heat-affect-zone (HAZ) softening due to reduced hardenability. These undesirable features are particularly detrimental in strain-based design of pipelines. Although the phenomenon of HAZ softening has been known for a long time, the impact of the HAZ softening on the integrity of pipeline girth welds was not well understood. The objective of this work was to understand the impact of HAZ softening on girth weld integrity. Finite element analysis was conducted to investigate the effects of HAZ softening on crack driving force and strain concentration in girth welds under longitudinal tensile loading. The material properties of WM and BM were obtained from an X100 girth weld. The HAZ was modeled as a functionally graded material based on its measured hardness. The models contained surface-breaking defects located at the fusion boundary simulating lack-of-sidewall fusion defects. The analysis results showed that increased CTOD driving force can be expected due to HAZ softening. The extent of increase is positively related to the width and degree of softening of the HAZ. On the other hand, weld strength overmatch reduces the total CTOD driving force. The strain concentration in the softened HAZ circumferentially remote from a surface-breaking defect was small. However, high strain concentration existed over the circumference covering the length of the defect. This concentration was primarily attributable to the existence of the defect and secondarily to the HAZ softening. One significant result from this work was that the relative increase in CTOD driving force and strain concentration due to HAZ softening was independent of defect size. In other words, on a relative basis, HAZ softening was no worse on large defects than on smaller defects. This result should be helpful in rationalizing the effects of HAZ softening for defects of various sizes that exist in field applications. Non-symmetrical crack-tip deformation occurred with softened HAZ. A large proportion of the crack-tip deformation was located in the HAZ. The magnitude of non-symmetric deformation increased with the increase of HAZ width and degree of softening. Even higher degree of non-symmetric deformation occurred with the increase of weld overmatching level. The structural significance of reduced total CTOD driving force and increased un-symmetric deformation at the crack tip due to weld strength overmatch warrants further study. The reduction in total CTOD driving force alone does not necessarily results in a higher level of weld integrity if the “intrinsic” toughness of the HAZ is substantially lower than the weld metal.
Out-of-Plane Bending Testing of Chain Links
Authors: Melis Cecil , Jean Phillipe , Vargas Pedro
Published: November 2008

Several mooring chains of an off-loading buoy failed after only 8 months of service. These chains were designed according to conventional fatigue assessment using API RP 2SK T-N curves to a fatigue life or 20 years with a factor of safety equal to 3 on life. Of particular interest is that the mooring chain failure underwent significant mooring chain motions that caused interlink rotations. Although traditionally neglected, these interlink rotations, when combined with significant chain tensions can cause bending stresses in the chain links. In this paper we identify a mechanism, here identified as Out-of-Plane Bending (OPB) that explains the extensive fatigue damage causing the mooring chains of the off-loading buoy to fail. A full scale test frame was constructed that has the capacity of applying inter-link rotation to a pre-tensioned chain. Although the test frame limits the number of links that can be tested together as a chain, a significant amount of testing was performed for the following chain sizes: 1. 81 mm Studded Grade R3S. 2. 107 mm Studdless Grade RQ3. 3. 124 mm Studless Grade R4. 4. 146 mm Studless Grade RQ4. Various pretension levels were used, with instrumentation to extract link angles and chain link stresses. In this paper the OPB mechanism is explained, and the test frame and results are presented. An empirical relationship is found to predict the OPB stresses in the chain links as a function of pretension and inter-link rotation. The OPB stress relationship obtained was applied to the failed mooring chain of the off-loading buoy with reasonable agreement. To comply with Single Buoy Moorings (SBM) requirements addressing publication of internal research, many of the graphs included in this paper have had the stress values removed from the y-axis. However, with SBM’s management approval, some numerical references to stress amplitudes remain in the text. Overall, this limitation does not detract from the study, trends are evident and relevant comparisons can be made.
HotPipe JIP: Design Guidelines for HP/HT Pipelines
Authors: Collberg Leif , Mo̸rk Kim J. , Levold Erik , Vitali Luigino
Published: November 2008

Recent development plans envisage the transport of hydrocarbons at temperature and pressure conditions far more severe than in past projects. Technical feasibility of certain inter field lines was put in doubt as a consequence of application of design guidelines currently in force. This fact gave rise to a critical review of design criteria. The HotPipe Project is a Joint Industry Research and Development Project, whose overall objective is to prepare a DNV Recommended Practice to be used in structural design of high temperature/high pressure pipelines. The DNV-RP will cover most practical cases where pipelines are subjected to high internal pressure and high temperature (HP/HT). The design criteria are based on the application of reliability methods to calibrate the partial safety factors in compliance with the safety philosophy established by DNV OS F101. The overall objective was pursued by performing the following subprojects: • Pipe Capacity: Experimental tests were carried out and FE models were developed aiming at establishing the failure mechanisms of thick pipes subjected to internal pressure, bending moment and axial compression under monotonic and cyclic loading conditions. • Pipe Response: Analytical tools and FE models were developed for studying the localization of buckling pattern for the envisaged pipeline scenarios i.e. pipelines laid on even sea bed, pipelines laid on uneven seabed and buried pipelines. • Mitigation Measures. Study of relevant mitigation measures and associated criteria for preventing/reducing/controlling additional pipeline bending. • Design Guideline. Preparation of the design guideline. The Joint Industry Project Hotpipe did recently finish the work and issued an internal confidential project guideline. This is in the process of being converted into a public DNV Recommended Practice, ref. DNV-RP-F110, which will be published later this year. It provides procedures and criteria to fulfill this functional requirement, to ensure the integrity of the pipeline in the post buckling condition. This paper will describe the procedures and criteria in the project guideline. It is expected to be identical in the coming RP issued for industry hearing. This paper describes the main structure and the covered design scenarios of the DNV-RP, particularly: • Pipelines exposed on even seabed, where thermal expansion may be accommodated by lateral snaking; • Pipelines on uneven seabed corresponding to even seabed; and • Pipelines on bottom of trenches/covered by natural or artificial backfill.
Background for Revision of DNV-RP-C203 Fatigue Analysis of Offshore Steel Structure
Authors: Lotsberg Inge
Published: November 2008

The last revision of the DNV recommended practice “Fatigue Analysis of Offshore Steel Structures” is from October 2001. During use of this standard some feed back from designers around the world have been received. Also some new research in the area has been performed in the time interval from it was first developed. It is also realised that the document is being used for fatigue design of some other types of details and structures than was thought of when the document was originally developed. Therefore it was now found convenient to revise the document to incorporate the experience gained and new research and developments made in the area of fatigue of offshore structures the last 7 years since the main content for this recommended practice was developed.