bluuebunny/crossref_metadata_2025 huggingface dataset:
Latino Disparities in Child Mental Health Services
Authors: Lopez Cyntia , Bergren Martha Dewey , Painter Susan G.
Published: July 2008

TOPIC:  Access and utilization of mental health services for Latino children.

PURPOSE:  As Latino children may experience higher rates of unmet needs, this article examines the current literature for the reasons for the disparity and the barriers to the utilization of mental health services for Latino children.

SOURCES:  An integrative literature review was undertaken from child psychiatry and nursing.

CONCLUSIONS:  The literature confirmed a pattern of underutilization of mental health services by Latino children, but did not completely address the reasons for the disparity. Suggested barriers were language and cultural issues. Gaps in the literature include a lack of agreement for definition of a mental health problem and the tools to identify these, insufficient studies into the barriers for Latino children in the access and utilization of mental health services, and cultural and language issues related to Latino research.
Bridging Cultures for Latino Children: School Nurse and Advanced Practice Nurse Partnerships
Authors: DeSocio Janiece , Elder Loretta , Puckett Sandra
Published: July 2008

TOPIC:  Barriers to use of mental health services by Latino families include stigma, service costs, and disparity of services with cultural values and traditions. School nurses are in key positions to recognize mental health needs of Latino children and form relationships that facilitate family connections with mental health services. Advanced practice psychiatric nurses may be contracted by school districts to provide consultation to school nurses or may be available to school nurses through connections with school‐based health centers. Case examples are provided to illustrate the value of school nurse consultation with an advanced practice psychiatric nurse in promoting awareness of cultural influences on children's symptoms and behaviors and developing culturally sensitive approaches to engage Latino children and families in school and health services.

PURPOSE:  This paper aims to review literature on Latino mental health and present rationale for school nurse and advanced practice nurse partnerships to promote culturally sensitive approaches that facilitate Latino family access and utilization of health services.

SOURCES:  Published literature and case scenarios.

CONCLUSIONS:  With advanced practice nurse consultation, school nurses identify mental health needs of Latino children and develop culturally sensitive approaches that bridge Latino families’ access to and utilization of health services.
Current Sexual Trauma Among High‐Risk Teen Mothers
Authors: Mylant MaryLou , Mann Colleen
Published: July 2008

PROBLEM:  The highest rate of reported intimate partner violence (IPV) is among women 15–45 years old (

Hart & Jamieson, 2001

) with 20% of pregnant teens reporting abuse (

Campbell, 1999

); however, little research on IPV and American Indian teen mothers has been done.

METHOD:  The purpose of this paper is to describe the degree of IPV and current sexual trauma among a group of Northern Plains adolescents being served by an American Indian teen mother program.

FINDINGS:  The relationship of trauma, substance abuse, and trauma symptoms are described. IPV was reported by 61% of the participants, with 37.5% reporting IPV during pregnancy and 22.5% reporting current sexual trauma.

CONCLUSIONS:  Development and testing of interventions for American Indian teen mothers, specifically related to trauma, are needed in addition to primary mental health services by agencies caring for this population.
Culture Bound Anxiety Disorder in Adolescence: A Case Study
Authors: Hamilton Joshua M.
Published: July 2008

TOPIC:  There are a number of culture‐bound syndromes in the literature that may directly impact on clients’ systems of meaning and, thus, the clinician's ability to effectively intervene. This applies to Hispanic/Latino children, particularly those who present with anxiety and somatic symptoms.

PURPOSE:  This case study deals with a 14‐year‐old Hispanic girl who presented at a behavioral health clinic with anxiety behaviors.

SOURCES:  Review of the literature and case example from practice.

CONCLUSION:  Since culture can have a profound influence on a child's thoughts, emotions, and behaviors, nurses’ cultural understanding is critical in psychiatric diagnostic evaluation and treatment.
A broad-line region origin for the iron Kα line in NGC 7213
Authors: Bianchi Stefano , La Franca Fabio , Matt Giorgio , Guainazzi Matteo , Jimenez Bailón Elena , Longinotti Anna Lia , Nicastro Fabrizio , Pentericci Laura
Published: July 2008

The X-ray spectrum of NGC 7213 is known to present no evidence for Compton reflection, a unique result among bright Seyfert 1s. The observed neutral iron Kα line, therefore, cannot be associated with a Compton-thick material, like the disc or the torus, but is due to Compton-thin gas, with the broad-line region (BLR) as the most likely candidate. To check this hypothesis, a long Chandra High-Energy Transmission Grating observation, together with a quasi-simultaneous optical spectroscopic observation at the ESO NTT EMMI were performed. We found that the iron line is resolved with a full width at half-maximum (FWHM) = 2400+1100−600 km s−1, in perfect agreement with the value measured for the broad component of the Hα, 2640+110−90 km s−1. Therefore, NGC 7213 is the only Seyfert 1 galaxy whose iron Kα line is unambiguously produced in the BLR. We also confirmed the presence of two ionized iron lines and studied them in greater detail than before. The resonant line is the dominant component in the Fe xxv triplet, therefore suggesting an origin in collisionally ionized gas. If this is the case, the blueshift of around 1000 km s−1 of the two ionized iron lines could be the first measure of the velocity of a starburst wind from its X-ray emission.
Self-consistent simulations of star cluster formation from gas clouds under the influence of galaxy-scale tidal fields
Authors: Hurley Jarrod R. , Bekki Kenji
Published: July 2008

We present the first results of a project aimed at following the formation and long-term dynamical evolution of star clusters within the potential of a host galaxy. Here, we focus on a model evolved within a simplified potential representing the Large Magellanic Cloud. This demonstrates for the first time the self-consistent formation of a bound star cluster from a giant molecular cloud. The model cluster reproduces the density profiles and structural characteristics of observed star clusters.
Key Features of Artificial Aquifers for Use in Modeling Contaminant Transport
Authors: Close Murray , Bright John , Wang Fuli , Pang Liping , Manning Maitland
Published: July 2008

Two large‐scale (9.5 m long, 4.7 m wide, 2.6 m deep), three‐dimensional artificial aquifers were constructed to investigate the influence of spatial variations in aquifer properties on contaminant transport. One aquifer was uniformly filled with coarse sand media (0.6 to 2.0 mm) and the other was constructed as a heterogeneous aquifer using blocks of fine, medium, and coarse sands. The key features of these artificial aquifers are described. An innovative deaeration tower was constructed to overcome a problem of the aquifers becoming blocked with excess air from the ground water source. A series of tracer injection experiments were conducted to test the homogeneity of the first aquifer that was purposely built as a homogeneous aquifer and to calculate values of aquifer parameters. Experimental data show that the aquifer is slightly heterogeneous, and hydraulic conductivity values are significantly higher down one side of the aquifer compared to the mean value. There was very good agreement in estimated dispersivity values between the plume area ratio methods and the curve fitting of tracer breakthrough curves. Dispersivity estimates from a full areal source injection (12.2 m2) experiment using a 1D analytical model were higher than estimates from a limited source injection (0.2 m2) experiment using a 3D model, possibly because the 1D model does not take account of the heterogeneity of hydraulic conductivity in the aquifer, thus overestimating dispersivity. Transverse and vertical dispersivity values were about five times less than the longitudinal dispersivity. There was slight sorption of Rhodamine WT onto the aquifer media.
Influence of anaerobic digestion on the carbon footprint of various sewage sludge treatment options
Authors: Barber William P. F.
Published: July 2008

This paper describes the results of a model set up to determine carbon footprints for sludge treatment solutions with and without standard or advanced anaerobic digestion. Complete and ‘gate’ (up to the point the sludge leaves the sewage works gate) footprints were calculated. The lowest carbon footprints corresponded with advanced digestion options, which reduced downstream energy and transport (hence carbon) requirements regardless of the endpoint of the sludge. The lowest complete carbon footprint solution coincided with advanced digestion, followed by drying with energy recovery. However, this option had the highest gate carbon footprint. In terms of gate carbon footprint, land application of an advanced digested sludge cake had the smallest footprint, followed by land application of dried pellets and finally incineration.
Strategic Reliabilism: A Naturalistic Approach to Epistemology
Authors: Bishop Michael A. , Trout J. D.
Published: July 2008

Strategic Reliabilism is a framework that yields relative epistemic evaluations of belief‐producing cognitive processes. It is a theory of cognitive excellence, or more colloquially, a theory of reasoning excellence (where ‘reasoning’ is understood very broadly as any sort of cognitive process for coming to judgments or beliefs). First introduced in our book, Epistemology and the Psychology of Human Judgment (henceforth EPHJ), the basic idea behind SR is that epistemically excellent reasoning is efficient reasoning that leads in a robustly reliable fashion to significant, true beliefs. It differs from most contemporary epistemological theories in two ways. First, it is not a theory of justification or knowledge – a theory of epistemically worthy belief. Strategic Reliabilism is a theory of epistemically worthy ways of forming beliefs. And second, Strategic Reliabilism does not attempt to account for an epistemological property that is assumed to be faithfully reflected in the epistemic judgments and intuitions of philosophers. If SR makes recommendations that accord with our reflective epistemic judgments and intuitions, great. If not, then so much the worse for our reflective epistemic judgments and intuitions.
Progressive Geopolitics
Authors: Kearns Gerry
Published: July 2008

Conservative geopolitics has assumed that the primary agents that matter in world affairs are states and, furthermore, that the primary relations that structure the world are those of force. Progressive geopolitics needs to question both assumptions. In this article, I explore some of the things that matter other than states and some of the relations that count other than force.
Space and Government: Governmentality and Geography
Authors: Huxley Margo
Published: July 2008

This essay outlines the main aspects of Foucault's notion of governmentality as a historically contingent and dispersed form of power seeking to act on the action of others and on the self. It explores conceptual dimensions of governmentality and its connections to Foucault's historical philosophical investigations of truths, rationalities and the subject. As a focus of geographical analysis, Foucauldian approaches first appear in historical geographies of disciplinary institutions, but this focus on the enclosed spaces of discipline also raises questions about the management of populations beyond the institutional walls. Governmentality approaches are now found in nearly every sub‐field of human geography, forming the basis of much innovative work exploring the significance of space in projects of government.
Household Food Security and Regional Geography: Livelihood Prospects in Nembudziya, Northwestern Zimbabwe
Authors: James Nick
Published: July 2008

Household food [in]security can be defined as the concept that underpins the various notions of relative food deprivation ranging from hunger, famine and malnutrition to seasonal shortages. The concept is also used to analyse and explain very different and complex livelihood realities at particular and local levels. Since the term emerged in the 1980s, it has gone through many changes and redefinition, but in this article the aim is to make general links to the geographies of food and other livelihood deprivations. The recent debates on livelihoods and participation link closely to the practical concerns around household food security. This article aims to present analysis that brings together regional understanding with insights into heterogeneity and the diversification of livelihoods and household food security in a particular region in Zimbabwe. Its argument is that such a multi‐scale analysis can give a fuller and more useful understanding of the differences and dynamics in household food security and therefore livelihood prospects in general. The regional political economy approach provides insight into the major external impacts in the region. The two most important of these have been the introduction of cotton and in‐migration, both occurring since the 1960s. A second level of analysis focuses on social relations and, hence, institutional developments within the region. These were relatively incomplete until the 1990s and since then the external forces, including the state and market forces, have determined the direction and emphasis of development in the region. Finally, the regional geography approach enables analysis of the local situation from cultural and identity perspectives. The livelihood possibilities are therefore related to social realities within and among the households. In conclusion, such regional empirical focus helps to give a fuller assessment of the unfolding household food security situation in northwestern Zimbabwe.
Quantitation and Mapping of Cerebral Detergent‐Insoluble Proteins in the Elderly
Authors: Woltjer Randall L. , Sonnen Joshua A. , Sokal Izabela , Rung Lisa G. , Yang Wan , Kjerulf John D. , Klingert Danielle , Johnson Charles , Rhew Isaac , Tsuang Debbie , Crane Paul K. , Larson Eric B. , Montine Thomas J.
Published: July 2008

Accumulation of abnormal protein aggregates, detergent‐insoluble (DI) proteins and amyloid in the brain are shared features of many neurodegenerative diseases. Previous studies correlating DI proteins and cognitive performance are limited. We addressed these limitations using two sets of autopsy brains, one selected from our Alzheimer's Disease Research Center and the other an unselected series from Adult Changes in Thought (ACT), a population‐based study of brain aging. We observed concentrations of 11 proteins and 6 protein variants that can be grouped into three highly correlated clusters: amyloid (A)β, tau and alpha‐synuclein (α‐syn). While abnormal proteins from each cluster independently correlated with cognitive performance in ACT participants, only increased soluble Aβ oligomers in temporal cortex and increased DI Aβ 42 and DI α‐syn in prefrontal cortex were negatively correlated with cognitive performance. These data underscore the therapeutic imperative to suppress processes leading to accumulation of soluble Aβ oligomers, DI Aβ 42 and DI α‐syn, highlight an at least partially independent contribution to cognitive impairment and raise the possibility that the priority for therapeutic targets may vary by brain region in a typical elderly US population.
Chordoid Glioma: A Case Report and Molecular Characterization of Five Cases
Authors: Horbinski Craig , Dacic Sanja , McLendon Roger E. , Cieply Kathy , Datto Michael , Brat Daniel J. , Chu Charleen T.
Published: July 2008

Chordoid gliomas are rare, slow‐growing neoplasms of the anterior third ventricle. We reported a case of chordoid glioma in a 41‐year‐old man with obstructive hydrocephalus. Histologically, the tumor consisted of polygonal epithelioid cells admixed with elongated cells in a myxoid stroma. A prominent lymphoplasmacytic infiltrate was present. The tumor cells expressed glial fibrillary acidic protein (GFAP), epithelial membrane antigen (EMA), vimentin, CD31, CD34, epidermal growth factor receptor (EGFR) and S100 but were negative for pankeratin and E‐cadherin. The percentage of Ki67 positive cells was approximately 3%. Weak p53 immunoreactivity was seen in less than 10% of the cells. Array comparative genomic hybridization performed on this case, as well as on four other archived cases, showed losses at several loci. Fluorescence in situ hybridization (FISH) confirmed consistent genetic alterations at 9p21 and 11q13. These are the fifth through ninth reported cases of chordoid gliomas with molecular characterization suggesting a distinct genetic origin from other gliomas.
Aroma Precursors and Methylpyrazines in Underfermented Cocoa Beans Induced by Endogenous Carboxypeptidase
Authors: Jinap S. , Ikrawan Y. , Bakar J. , Saari N. , Lioe H.N.
Published: July 2008

ABSTRACT:  Cocoa‐specific aroma precursors and methylpyrazines in underfermented cocoa beans obtained from fermentation induced by indigenous carboxypeptidase have been investigated. Fermentation conditions and cocoa bean components were analyzed during 0 to 3 d of fermentation. Underfermented cocoa beans were characterized as having hydrophilic peptides and free hydrophobic amino acids much higher than unfermented ones. These 2 key components of cocoa aroma precursors may be produced from the breakdown of proteins and polypeptides by endogenous carboxypeptidase during the fermentation process. The enzyme was activated during fermentation. Polypeptides of 47, 31, and 19 kDa were observed in the samples throughout the 3‐d fermentation period; however, only the first 2 polypeptides were remarkably reduced during fermentation. Since the 1st day of fermentation, underfermented cocoa beans contained methylpyrazines, a dominant group of cocoa‐specific aroma. This might be due to microbial activities during fermentation, observed through a decrease of pH value and an increase of temperature of cocoa beans. The concentration of tetramethylpyrazines was significantly increased during the 3 d of fermentation. This may increase the cocoa‐specific flavor to the beans.
Cross‐sectional study of canine leptospirosis in animal shelter populations in mainland Australia
Authors: Zwijnenberg RJG , Smythe LD , Symonds ML , Dohnt MF , Toribio J‐ALML
Published: July 2008

Objective  To measure the prevalence of canine leptospirosis in Queensland and to detect infection, if present, in New South Wales, Victoria, South Australia, Western Australia and the Northern Territory by measuring the serological titres of dogs held in animal shelters.

Procedure  Samples were collected through stratified sampling from multiple dog shelters in Queensland and New South Wales, and from one dog shelter located in close proximity to a major urban area in Victoria, South Australia, the Northern Territory and Western Australia. All samples were analysed using the microscopic agglutination test at the WHO/FAO/OIE Collaborating Centre for Reference & Research on Leptospirosis, Queensland Health Scientific Services in Brisbane, Queensland.

Results  Of a total of 956 samples submitted, 18 (1.9%) had positive leptospirosis titres. True prevalence measured in Queensland was estimated to be 2.5%, and the true prevalence in New South Wales, Victoria, South Australia, Western Australia and the Northern Territory was estimated to be 2.3%, 2.8%, 0%, 1% and 1.1% respectively. An association was found between seropositive status and female dogs (odds ratio (OR) 1.92) and seropositive status and the age group 1 to < 3 years (OR 1.41). Although 11 different serovars were detected, Leptospira interrogans serovar Copenhageni was the most prevalent and was found in 4 of the 18 positive dogs as a single infection.

Conclusion  Serological evidence of canine leptospirosis in five states in mainland Australia indicates that the disease is more broadly distributed than previously thought.
Dysgonic strain of Microsporum canis pseudomycetoma in a Domestic Long‐hair cat
Authors: Thian A , Woodgyer AJ , Holloway SA
Published: July 2008

A 4‐year‐old Domestic Long‐hair cat was presented with two large non‐painful, ulcerated and suppurative lesions over the flanks. Histopathology and cytology were consistent with fungal pyogranulomatous inflammation. Culture of tissue yielded a dysgonic strain of Microsporum canis. The cat was treated successfully by staged en bloc resections of the lesions, followed by oral ketoconazole, then oral terbinafine. This is the first reported case of dermatophytic pseudomycetoma in a Domestic Long‐hair cat in Australia.
Antimicrobial Photodynamic Efficacy of Side‐chain Functionalized Benzo[a]phenothiazinium Dyes
Authors: Verma Sarika , Sallum Ulysses W. , Athar Humra , Rosenblum Lauren , Foley James W. , Hasan Tayyaba
Published: July 2008

5‐(Ethylamino)‐9‐diethylaminobenzo[a]phenothiazinium chloride (EtNBS) is a photosensitizer (PS) with broad antimicrobial photodynamic activity. The objective of this study was to determine the antimicrobial photodynamic effect of side chain/end group modifications of EtNBS on two representative bacterial Gram‐type‐specific strains. Two EtNBS derivatives were synthesized, each functionalized with a different side‐chain end‐group, alcohol or carboxylic acid. In solution, both exhibited photochemical properties consistent with those of the EtNBS parent molecule. In vitro photodynamic therapy experiments revealed an initial Gram‐type‐specificity with two representative strains; both derivatives were phototoxic to Staphylococcus aureus 29213 but the carboxylic acid derivative was nontoxic to Escherichia coli 25922. This difference in photodynamic efficacy was not due to a difference in the binding of the two molecules to the bacteria as the amount of both derivatives bound by bacteria was identical. Interestingly, the carboxylic acid derivative produced no fluorescence emission when observed in cultures of E. coli via fluorescence microscopy. These early findings suggest that the addition of small functional groups could achieve Gram‐type‐specific phototoxicity through altering the photodynamic activity of PSs and deserve further exploration in a larger number of representative strains of each Gram type.
Cultural Differences in the Self: From Philosophy to Psychology and Neuroscience
Authors: Zhu Ying , Han Shihui
Published: July 2008

Different thinking styles in Westerners and Chinese (analytic vs. holistic) lead to disparities between the two cultures not only in perception and attention but also in high‐level social cognition such as self‐representation. Most Western philosophers discussed the self by focusing on personal self‐identity, whereas Chinese philosophers emphasized the relation between the self and others. Dissimilar philosophical thinking of the self is associated with distinct cognitive styles of self‐representation (i.e., the independent self in Westerners and the interdependent self in Chinese). Recent brain imaging studies found that Westerners employed the medial prefrontal cortex to represent only the individual self, whereas Chinese utilized the same brain area to represent both the self and close others, providing neural basis of cultural differences in self‐representation. We suggest that the cultural differences in thinking styles between Westerners and Chinese influence both psychological and neural structure of self‐representation.
Patients' Perceptions of Physician‐Patient Discussions and Adverse Events with Cancer Therapy
Authors: Hershman Dawn , Calhoun Elizabeth , Zapert Kinga , Wade Shawn , Malin Jennifer , Barron Rich
Published: July 2008

Objectives.  Patients with cancer who are treated with chemotherapy report adverse events during their treatment, which can affect their quality of life and increase the likelihood that their treatment will not be completed. In this study, patients’ perceptions of the physician‐patient relationship and communication about cancer‐related issues, particularly adverse events were examined.

Methods.  We surveyed 508 patients with cancer concerning the occurrence of adverse events and their relationship and communication with their physicians regarding cancer, treatment, and adverse events.

Results.  Most individuals surveyed (>90%) discussed diagnosis, treatment plan, goals, and schedule, and potential adverse events with their physicians before initiating chemotherapy; approximately 75% of these individuals understood these topics completely or very well. Physician‐patient discussions of adverse events were common, with tiredness, nausea and vomiting, and loss of appetite discussed prior to chemotherapy in over 80% of communications. These events were also the most often experienced (ranging in 95% to 64% of the respondents) along with low white blood cell counts (WBCs), which were experienced in 67% of respondents. Approximately 75% of the individuals reported that their overall quality of life was affected by adverse events.

Conclusions.  These findings suggest that discussions alone do not provide patients with sufficient understanding of the events, nor do they appear to adequately equip patients to cope with them. Therefore, efforts to improve cancer care should focus on developing tools to improve patients’ understanding of the toxicities of chemotherapy, as well as providing resources to reduce the effects of adverse events.
On the History and Practice of Unilateralism in East Asia: Or, the More Things Change, the More They Remain the Same
Authors: Cumings Bruce
Published: July 2008

This paper argues that multilateralism continues to be weak in East Asia, an outcome that traces back to the post‐World War II settlement and the Korean War. Hot war and cold war divisions hindered (and often completely blocked) horizontal relations and communications among the East Asian countries. Most diplomatic communication was vertical, that is, from the foreign ministries in Tokyo, Seoul, Manila or Taipei to Washington and back again. This vertical diplomacy was punctured horizontally by economic forces, which since the 1960s have eroded and bypassed Cold War boundaries, bringing former adversaries together – but primarily through business contacts and pop culture, not through multilateral institutions. The key anomaly in the past 60 years is China, which was the subject of the single most important breach in the structure and logic of American Cold War power in the region – the Nixon/Carter opening to China in the 1970s. If the first phase of the Cold War emphasized security considerations and divided the region, and the second phase exemplified the ascendancy of economic development and accelerated regional integration, it is important to remember that both these tendencies occurred primarily because of basic shifts in American foreign policy and the resulting pressures on East Asian states. Again, China's turn outward to the world economy and its rapid growth is the best expression of this tendency today, but China is also replicating what Japan, South Korea, and Taiwan did in the past. Contemporary obstacles to deeper integration in the region also trace back to Washington (although not only to Washington). Rightly or wrongly, the USA still holds the key to East Asian regional security and cooperation. The USA remains the key enabler of either multilateralism or unilateralism in East Asia, and East Asian leaders are still on the outside looking in.
Challenging the Democratic Peace? Historical Memory and the Security Relationship between Japan and South Korea1
Authors: Midford Paul
Published: July 2008

The logic of the democratic peace suggests that as two democracies, Japan and South Korea should not have militarized conflicts between them, while mutual recognition of their democratic systems should have a corresponding mutual reassurance effect. On the other hand, historical memories of Japan's colonialization of Korea provide a basis for Koreans to mistrust Japan's disposition, if not its intentions. This article considers whether the 2006 Japanese–Korean dispute over maritime exploration near the disputed Dokdo/Takeshima was a militarized dispute, and whether Japan's status as a democracy has been sufficient to reassure South Korea that Japan does not pose a military threat. The results of this case study will shed light on the question of whether, and if so under what conditions, historically rooted mistrust might trump the causal variables underpinning the democratic peace.
State–Society Relations in South Korea after Democratization: Is the Strong State Defunct?
Authors: Kim Sunhyuk , Han Chonghee , Jang Jiho
Published: July 2008

This paper argues that the two recent structural transformations of political democratization and market‐oriented economic restructuring have not considerably reduced the role of the strong state in South Korea. Focusing on three sectors (civic groups, big business associations, and labor unions), this paper demonstrates that the strong state in South Korea, by selecting and aligning with different social groups, has been effectively pursuing self‐set reform goals despite the opposition of labor and capital. While the “old” strong state during the authoritarian era used coercion and repression to induce compliance of labor and capital, the “new” strong state after democratization relies on different methods such as coalitions with social groups to legitimize, publicize, and execute its preferred reform policies. The persistence of a strong state in South Korea provides fertile ground for reflecting on the complex relationship between state strength and the quality of democracy.
Mixed-Mode Dynamic Crack Growth in a Functionally Graded Particulate Composite: Experimental Measurements and Finite Element Simulations
Authors: Kirugulige Madhu , Tippur Hareesh V.
Published: July 2008

Mixed-mode dynamic crack growth behavior in a compositionally graded particle filled polymer is studied experimentally and computationally. Beams with single edge cracks initially aligned in the direction of the compositional gradient and subjected to one-point eccentric impact loading are examined. Optical interferometry along with high-speed photography is used to measure surface deformations around the crack tip. Two configurations, one with a crack on the stiffer side of a graded sheet and the second with a crack on the compliant side, are tested. The observed crack paths are distinctly different for these two configurations. Furthermore, the crack speed and stress intensity factor variations between the two configurations show significant differences. The optical measurements are examined with the aid of crack-tip fields, which incorporate local elastic modulus variations. To understand the role of material gradation on the observed crack paths, finite element models with cohesive elements are developed. A user-defined element subroutine for cohesive elements based on a bilinear traction-separation law is developed and implemented in a structural analysis environment. The necessary spatial variation of material properties is introduced into the continuum elements by first performing a thermal analysis and then by prescribing material properties as temperature dependent quantities. The simulated crack paths and crack speeds are found to be in qualitative agreement with the observed ones. The simulations also reveal differences in the energy dissipation in the two functionally graded material (FGM) cases. T-stresses and hence the crack-tip constraint are significantly different. Prior to crack initiation, larger negative T-stresses near the crack tip are seen when the crack is situated on the compliant side of the FGM.
Mixed-Mode Fracture Analysis of Orthotropic Functionally Graded Material Coatings Using Analytical and Computational Methods
Authors: Dag Serkan , Ilhan K. Ayse
Published: July 2008

This article presents analytical and computational methods for mixed-mode fracture analysis of an orthotropic functionally graded material (FGM) coating-bond coat-substrate structure. The analytical solution is developed by considering an embedded crack in the orthotropic FGM coating. The embedded crack is assumed to be loaded through arbitrary self-equilibrating mixed-mode tractions that are applied to its surfaces. Governing partial differential equations for each of the layers in the trilayer structure are derived in terms of the effective parameters of plane orthotropic elasticity. The problem is then reduced to a system of two singular integral equations, which is solved numerically to evaluate the mixed-mode crack tip parameters. The computational approach is based on the finite element method and is developed by applying the displacement correlation technique. The use of two separate methods in the analyses allowed direct comparisons of the results obtained for an embedded crack in the orthotropic FGM coating, leading to a highly accurate numerical predictive capability. The finite element based approach is used to generate further numerical results by considering periodic cracking in the orthotropic FGM coating. Parametric analyses presented in this article illustrate the influences of the material nonhomogeneity and orthotropy constants, the bond coat thickness, and the crack periodicity on the mixed-mode stress intensity factors and the energy release rate.
A Parallel Domain Decomposition BEM Algorithm for Three-Dimensional Exponentially Graded Elasticity
Authors: Ortiz J. E. , Shelton W. A. , Mantič V. , Criado R. , Gray L. J. , París F.
Published: July 2008

A parallel domain decomposition boundary integral algorithm for three-dimensional exponentially graded elasticity has been developed. As this subdomain algorithm allows the grading direction to vary in the structure, geometries arising from practical functionally graded material applications can be handled. Moreover, the boundary integral algorithm scales well with the number of processors, also helping to alleviate the high computational cost of evaluating the Green’s functions. For axisymmetric plane strain states in a radially graded material, the numerical results for cylindrical geometries are in excellent agreement with the analytical solution deduced herein.
A Generalized Interaction Integral Method for the Evaluation of the T-Stress in Orthotropic Functionally Graded Materials Under Thermal Loading
Authors: Kim Jeong-Ho , KC Amit
Published: July 2008

The interaction integral method that is equipped with the nonequilibrium formulation is generalized to evaluate the nonsingular T-stress as well as mixed-mode stress intensity factors in orthotropic functionally graded materials under thermomechanical loads. This paper addresses both Mode-I and mixed-mode fracture problems and considers various types of orthotropic material gradation. The orthotropic thermomechanical material properties are graded spatially and integrated into the element stiffness matrix using the direct Gaussian formulation. The types of orthotropic material gradation considered include exponential, power-law, and hyperbolic-tangent functions, and the numerical formulation is generalized for any type of smooth material gradation. The T-stress and mixed-mode stress intensity factors are evaluated by means of the interaction integral method developed in conjunction with the finite element method. The accuracy of numerical results is assessed by means of thermomechanically equivalent problems.
Mechanical Modeling of Thin Films and Cover Plates Bonded to Graded Substrates
Authors: Guler Mehmet A.
Published: July 2008

In this study, the contact problems of thin films and cover plates are considered. In these problems, the loading consists of any one or combination of stresses caused by uniform temperature changes and temperature excursions, far field mechanical loading, and residual stresses resulting from film processing or welding. The primary interest in this study is in examining stress concentrations or singularities near the film ends for the purpose of addressing the question of crack initiation and propagation in the substrate or along the interface. The underlying contact mechanics problem is formulated by assuming that the film is a “membrane” and the substrate a graded elastic continuum, and is solved analytically by reducing it to an integral equation. The calculated results are the interfacial shear stress between the film and the graded substrate, the Mode II stress intensity factor at the end of the film, and the axial normal stress in the film. The results indicate that grading the material properties of the substrate helps to decrease the film stresses and the stress intensity factors at the free edges and to lower the axial normal stresses at the midsection where the film is most likely to crack.
Analysis of Interacting Cracks Using the Generalized Finite Element Method With Global-Local Enrichment Functions
Authors: Kim Dae-Jin , Duarte Carlos Armando , Pereira Jeronymo Peixoto
Published: July 2008

This paper presents an analysis of interacting cracks using a generalized finite element method (GFEM) enriched with so-called global-local functions. In this approach, solutions of local boundary value problems computed in a global-local analysis are used to enrich the global approximation space through the partition of unity framework used in the GFEM. This approach is related to the global-local procedure in the FEM, which is broadly used in industry to analyze fracture mechanics problems in complex three-dimensional geometries. In this paper, we compare the effectiveness of the global-local FEM with the GFEM with global-local enrichment functions. Numerical experiments demonstrate that the latter is much more robust than the former. In particular, the GFEM is less sensitive to the quality of boundary conditions applied to local problems than the global-local FEM. Stress intensity factors computed with the conventional global-local approach showed errors of up to one order of magnitude larger than in the case of the GFEM. The numerical experiments also demonstrate that the GFEM can account for interactions among cracks with different scale sizes, even when not all cracks are modeled in the global domain.
Effective Thermal Conductivity of Functionally Graded Particulate Nanocomposites With Interfacial Thermal Resistance
Authors: Yin H. M. , Paulino G. H. , Buttlar W. G. , Sun L. Z.
Published: July 2008

By means of a fundamental solution for a single inhomogeneity embedded in a functionally graded material matrix, a self-consistent model is proposed to investigate the effective thermal conductivity distribution in a functionally graded particulate nanocomposite. The “Kapitza thermal resistance” along the interface between a particle and the matrix is simulated with a perfect interface but a lower thermal conductivity of the particle. The results indicate that the effective thermal conductivity distribution greatly depends on Kapitza thermal resistance, particle size, and degree of material gradient.
Buckling of a Circular Plate Resting Over an Elastic Foundation in Simple Shear Flow
Authors: Luo Haoxiang , Pozrikidis C.
Published: July 2008

The elastic instability of a circular plate adhering to an elastic foundation modeling the exposed surface of a biological cell resting on the cell interior is considered. Plate buckling occurs under the action of a uniform body force due to an overpassing simple shear flow distributed over the plate cross section. The problem is formulated in terms of the linear von Kármán plate bending equation incorporating the body force and the elastic foundation spring constant, subject to clamped boundary conditions around the rim. The coupling of the plate to the substrate delays the onset of the buckling instability and may have a strong effect on the shape of the bending eigenmodes. Contrary to the case of uniform compression, as the shear stress of the overpassing shear flow increases, the plate always first buckles in the left-to-right symmetric mode.
Computer Based Process Piping Stress Analysis: ASME B31.3 Appendix S — Example S1
Authors: Edwards Don R.
Published: July 2008

The American Standards Association (ASA) B31.3-1959 Petroleum Refinery Piping Code [1] grew out of an ASA document that addressed all manner of fluid conveying piping systems. ASA B31.3 was created long before widespread engineering use of computer “mainframes” or even before the inception of piping stress analysis software. Also as B31.3 continued to pass thru standards organizations from ASA, ANSI, to ASME, the B31.3 Process Piping Code [2] (hereafter referred to as the “Code”) has remained ambiguous over the past few decades in several areas. Ambiguities such as what temperatures and pressures are to be used during the pipe stress analysis process is addressed but apparently not clearly enough to make the point; the prevailing practice in the industry is to use the design pressure and temperature; but this is an incorrect inference from the Code. The misunderstandings as to the few, albeit very important, purposed uses for the design pressure and design temperature also appear to be prevalent in the industry. This paper describes some of these subtle yet possibly radical concepts that were included in the ASME B31.3-2004 Appendix S Example Sl. This paper discusses: • the design and analysis procedures in defining when the design conditions are actually to be used; • when and in what manner the most severe set of operating temperature and pressure is to be used; • and the debates that lasted over a decade to finally include into the Code such “seemingly simple” examples that address computer based stress analysis.
Post Fire Transient Temperature Distribution in Drum Type Packages
Authors: Smith Allen C.
Published: July 2008

This study investigates the temperature distribution in an idealized cylindrical package subjected to the HAC Fire transient. Cases for several common overpack materials, with thermal conductivity spanning two orders of magnitude, are considered. The results show that the interior temperature distribution and maximum interior temperature are determined by the heat generation of the contents and the thermal resistance of the package materials. Heat generation has a dominant effect on the peak temperature in the center (containment vessel region) of the package, when the internal thermal resistance is high. For cases where the internal resistance is low, heat conducted into the interior during the fire determines the peak temperature in the center, containment vessel region. The thermal wave effect, where the interior temperature continues to rise after the end of the fire exposure, is present in all cases. The study complements the parametric studies of effects of thermal properties on thermal response of packages which were previously reported.
A New Ni-Cr-Mo-Based Gadolinium Structural Alloy for Neutron Adsorption Application in Radioactive Material Packages
Authors: McConnell Paul , Robino Charles , Mizia Ron , DuPont John , Wachs Gregg , Hurt William
Published: July 2008

In order to avoid restrictive fissile loading limits in some types of US Department of Energy (DOE) spent nuclear fuel, nuclear criticality control measures are needed in standardized waste packages for long-term disposal of high-level radioactive materials in the proposed Yucca Mountain repository. This need has been addressed by development of a corrosion-resistant, neutron-absorbing structural alloy for nuclear criticality control. Applications for the alloy include internals (e.g., baskets) for storage, transportation, and disposal of radioactive material (RAM). This paper outlines results of a metallurgical development program that alloyed gadolinium into a nickel-chromium-molybdenum matrix. Gadolinium was chosen as a neutron-absorption alloying element due to its high thermal neutron absorption cross section and low solubility in the anticipated repository environment. The nickel-chromium-molybdenum alloy family was chosen for its known corrosion performance, mechanical properties, and weldability. An ASTM International Material Specification has been issued for the alloy and a Code Case has been approved by the American Society of Mechanical Engineers for RAM package applications. Mechanical and physical property data for the alloy are provided in this paper.
Design Fatigue Life Comparison of ASME Section VIII and EN 13445 Vessels With Welded Joints
Authors: Kalnins Arturs , Rana Mahendra , Karcher Guido G.
Published: July 2008

In a recent study conducted by the European Commission, design fatigue life of welded vessels allowed by the ASME Boiler and Pressure Vessel Code was compared with that of the European Standard EN 13445. The allowable number cycles of the ASME Code was reported to be much larger than that of EN 13445, and, therefore, the ASME Code was regarded as unconservative for welded regions. This paper investigates the reason for the reported discrepancy between the two design codes. It is found that, when calculating the allowable cycles reported in the study using the ASME Code as a basis, no fatigue strength reduction factor on stress was used, which is contrary to the ASME Code design rules for welded joints. This paper recalculates the allowable cycles according to ASME Code rules and concludes that they are comparable with those of EN 13445.
Assessing the Impact of Equipment Aging on System Performance Using Simulation Modeling Methods
Authors: Gupta N. K.
Published: July 2008

The radiological Inductively Coupled Plasma Mass Spectrometer (ICP-MS) is used to analyze the radioactive samples collected from different radioactive material processing operations at Savannah River Site (SRS). The expeditious processing of these samples is important for safe and reliable operations at SRS. As the radiological (RAD) ICP-MS machine ages, the experience shows that replacement parts and repairs are difficult to obtain on time for reliable operations after 5 years of service. A discrete event model using commercial software EXTEND was prepared to assess the impact on sample turn around times as the ICP-MS gets older. The model was prepared using the sample statistics from the previous 4 years. Machine utilization rates were calculated for the new machine, 5 year old machine, 10 year old machine, and a 12 year old machine. Computer simulations were run for these periods and the sample delay times calculated. The model was validated against the sample statistics collected from the previous 4 quarters. 90% confidence intervals were calculated for the 10th, 25th, 50th, and 90th quantiles of the samples. The simulation results show that if 50% of the samples are needed on time for efficient site operations, a 10 year old machine could take nearly 50 days longer to process these samples than a 5-year old machine.
Life Assessment by Monitoring Biaxial Strain-Rates in High Temperature Steam Pipelines
Authors: Morris Andrew , Dear John , Kourmpetis Miltiadis
Published: July 2008

Most of the main coal fired stations in the UK are operating beyond their original design life and it is essential to be able to manage the integrity of the high temperature pipework systems, for both commercial and safety reasons. The fossil fired plant in the UK has operated flexibly for a number of years, which complicates the remanent life assessment of a pipework system. This paper specifically addresses monitoring the creep strain accumulation over time of high temperature pressurized steam pipes in order to better quantify the remanent life and thereby provide improved advice on run/repair/replace issues. Any monitoring instrumentation needs to be rugged and able to endure what is a hostile environment and provide reliable strain measurements in both the longitudinal and circumferential directions of the pipe. This paper presents one monitoring method that has been developed for service use. The monitoring system uses a specially designed strain gauge that carries optical targets, image capture and analysis is used to determine the in-service creep strain rates. Experiences from site installations will be described.