bluuebunny/crossref_metadata_2025 huggingface dataset:
Seismic Design of Friction-Damped Braced Frames Based on Historical Records
Authors: Levy Robert , Lavan Oren , Rutenberg Avigdor
Published: August 2005

This paper is concerned with the design of friction dampers designed to slip at a predetermined level and dissipate a substantial portion of the seismic energy, leaving the structure practically intact without its members having to yield or buckle. They are appropriate for use in seismic design of new buildings and in retrofitting existing structures. By choosing a practical design requirement rather than minimizing some energy criterion, a novel design procedure attains the stiffness of the individual braces and their displacements at the threshold of activation. The procedure is a two-phase process that uses in Phase 1 an equivalent single-degree-of-freedom (SDOF) system to obtain an optimal natural period of the structure by performing a full nonlinear dynamic analysis for a set of earthquake records. Phase 2 then enforces the same first mode on both the braced and unbraced frames, with the aim of ensuring simultaneous slippage. The procedure was applied to a 10-story steel frame. It yielded a rather technically attractive design of the braces since for close to mean plus standard deviation of the records, the resulting maximum roof displacements fell within the allowable design, as initially constrained to, and simultaneous slip of all braces occurred for most records. This procedure is rather simple in that the main computational effort, i.e., nonlinear analysis needed for Phase 1, is performed on an equivalent SDOF system only, whereas analysis of the multi-degree-of-freedom (MDOF) system is a linear eigenvalue analysis.
A Damage Model for Practical Seismic Design that Accounts for Low Cycle Fatigue
Authors: Teran-Gilmore Amador , Jirsa James O.
Published: August 2005

The structural properties of a structure deteriorate when deformations reach the range of inelastic behavior. A possible consequence of deterioration of the hysteretic behavior of a structure is failure of critical elements at deformation levels that are significantly smaller than its ultimate deformation capacity. Seismic design methodologies that account for low cycle fatigue can be formulated using the concept of target ductility. The practical use of one such methodology requires the consideration of simple low cycle fatigue models that consider the severity of repeated loading through a normalized plastic energy parameter. The inconsistencies inherent to the use of such indices can be corrected through simple empirical rules derived from an understanding of the effect of the history of energy dissipation in the assessment of the level of structural damage.
Evaluation of Modal and FEMA Pushover Procedures Using Strong-Motion Records of Buildings
Authors: Goel Rakesh K.
Published: August 2005

The objective of this investigation is to evaluate the FEMA-356 Nonlinear Static Procedure (NSP) and a recently developed Modal Pushover Analysis (MPA) procedure using recorded motions of four buildings that were damaged during the 1994 Northridge earthquake. For this purpose, displacements and drifts from the FEMA-356 NSP and the MPA procedures are compared with the values “derived” from the recorded motions. It is found that the FEMA-356 NSP typically underestimates the drifts in upper stories and overestimates them in lower stories when compared to the recorded motions. Among the four FEMA-356 distributions considered, the “Uniform” distribution led to the most excessive underestimation or overestimation indicating that the need to carefully reevaluate the usefulness of this distribution in the FEMA-356 NSP. Furthermore, FEMA-356 distributions failed to provide accurate estimates of story drifts for a building that satisfied the FEMA-356 criterion for detecting the presence of higher mode effects indicating the need to carefully re-examine this criterion. The MPA procedure, in general, provides estimates of the response that are much closer to the values from the recorded motion compared to those from the FEMA-356 NSP. In particular, the MPA procedure, unlike the FEMA-356 NSP, is able to capture the effects of higher modes. For a building that exhibits dominant effects of “soft” first story, however, neither the MPA procedure nor the FEMA-356 NSP led to reasonable estimate of the response.
Classification and Prioritization of Essential Systems in Hospitals under Extreme Events
Authors: Myrtle Robert C. , Masri Sami F. , Nigbor Robert L. , Caffrey John P.
Published: August 2005

This paper presents a classification and prioritization of nonstructural systems, including medical equipment, in hospitals based upon the results of extensive surveys of effects of major seismic events. Surveys included damage surveys, interviews of medical and administrative personnel, and solicitation of expert opinion. As part of a larger study on nonstructural mitigation in hospitals, this effort sought to identify the importance and interdependence of various nonstructural systems subjected to earthquakes and other extreme events. Focused information was obtained for the 1994 Northridge earthquake. Additional information was obtained from experiences in the 1995 Kobe earthquake, the 1999 Chi-Chi earthquake, and the 1999 Kocaeli earthquake. Survey results led to a prioritized list of hospital nonstructural systems that can aid mitigation efforts in maximizing the continued functionality of essential medical facilities when exposed to extreme events.
Record Selection for Nonlinear Seismic Analysis of Structures
Authors: Iervolino Iunio , Cornell C. Allin
Published: August 2005

This study addresses the question of selection and amplitude scaling of accelerograms for predicting the nonlinear seismic response of structures. Despite the current practices of record selection according to a specific magnitude-distance scenario and scaling to a common level, neither aspect of this process has received significant research attention to ascertain the benefits or effects of these practices on the conclusions. This paper hypothesizes that neither these usual principal seismological characteristics nor scaling of records matters to the nonlinear response of structures. It then investigates under what conditions this hypothesis may not be sustainable. Two classes of records sets are compared in several case studies: one class is carefully chosen to represent a specific magnitude and distance scenario, the other is chosen randomly from a large catalog. Results of time-history analyses are formally compared by a simple statistical hypothesis test to assess the difference, if any, between nonlinear demands of the two classes of records. The effect of the degree of scaling (by first-mode spectral acceleration level) is investigated in the same way. Results here show (1) little evidence to support the need for a careful site-specific process of record selection by magnitude and distance, and (2) that concern over scenario-to-scenario record scaling, at least within the limits tested, may not be justified.
Differential Gene Expression in Ovarian Tumors Reveals Dusp 4 and Serpina 5 As Key Regulators for Benign Behavior of Serous Borderline Tumors
Authors: Sieben Nathalie L.G. , Oosting Jan , Flanagan Adrienne M. , Prat Jaime , Roemen Guido M.J.M. , Kolkman-Uljee Sandra M. , van Eijk Ronald , Cornelisse Cees J. , Fleuren Gert Jan , van Engeland Manon
Published: August 2005

Purpose

Ovarian serous borderline tumors (SBT) are characterized by arborizing papillae lined by stratified epithelial cells, varying atypia, and absence of stromal invasion. Originally, these tumors have been classified as borderline because they behaved in a remarkably indolent manner, even with widespread tumor deposits called implants and the presence of lymph node involvement. The molecular biology of these lesions has just begun to be explored. High prevalence of B-RAF/K-RAS mutations in SBTs in contrast to serous carcinomas (SCAs) indicates that the mitogenic RAS-RAF-MEK-ERK-MAP kinase pathway is crucial for the pathogenesis of SBTs. The purpose of this study was to further unravel the genetic pathways through which SBTs develop, with a special focus on explaining the generally benign SBT behavior.

Materials and Methods

We generated RNA expression profiles of 38 ovarian serous neoplasms. Global Test pathway analysis and significance analysis of microarrays (SAM) of the expression profiles was performed.

Results

SAM and Global Testing showed that although the mitogenic pathway is activated in SBTs, activation of downstream genes involved in extracellular matrix (ECM) degradation is absent, suggesting an uncoupling of both events. In addition, we show that two genes involved in regulating this uncoupling, ERK-inhibitor Dusp 4 and uPA-inhibitor Serpina 5, are downregulated in SCAs in contrast to SBTs. In SCAs, this was associated with downstream MMP-9 activation at both mRNA and protein level.

Conclusion

We propose that the putative tumor suppressor genes Dusp 4 and Serpina 5 provide a major clue to the indolent behavior of SBTs.
Chemoendocrine Therapy for Premenopausal Women With Axillary Lymph Node–Positive, Steroid Hormone Receptor–Positive Breast Cancer: Results From INT 0101 (E5188)
Authors: Davidson Nancy E. , O'Neill Anne M. , Vukov Allen M. , Osborne C. Kent , Martino Silvana , White Douglas R. , Abeloff Martin D.
Published: August 2005

Purpose

Chemotherapy, tamoxifen, and ovarian ablation/suppression (OA/OS) are effective adjuvant approaches for premenopausal, steroid hormone receptor–positive breast cancer. The value of combined therapy has not been clearly established.

Patients and Methods

Premenopausal women with axillary lymph node–positive, steroid hormone receptor–positive breast cancer (1,503 eligible patients) were randomly assigned to six cycles of cyclophosphamide, doxorubicin, and fluorouracil (CAF), CAF followed by 5 years of monthly goserelin (CAF-Z), or CAF followed by 5 years of monthly goserelin and daily tamoxifen (CAF-ZT). The primary end points were time to recurrence (TTR), disease-free survival (DFS), and overall survival (OS) for CAF-Z versus CAF, and CAF-ZT versus CAF-Z.

Results

With a median follow-up of 9.6 years, the addition of tamoxifen to CAF-Z improved TTR and DFS but not OS. There was no overall advantage for addition of goserelin to CAF.

Conclusion

Addition of tamoxifen to CAF-Z improves outcome for premenopausal node-positive, receptor-positive breast cancer. The role of OA/OS alone or with other endocrine agents should be studied more intensely.
Role of Depression As a Predictor of Mortality Among Cancer Patients After Stem-Cell Transplantation
Authors: Prieto Jesús M. , Atala Jorge , Blanch Jordi , Carreras Enric , Rovira Montserrat , Cirera Esteve , Espinal Anna , Gasto Cristóbal
Published: August 2005

Purpose

To determine the association between depression and survival among cancer patients at 1, 3, and 5 years after stem-cell transplantation (SCT).

Patients and Methods

This was a prospective cohort study of 199 hematologic cancer patients who survived longer than 90 days after SCT and who were recruited in a University-based hospital between July 1994 and August 1997. Patients received a psychiatric assessment at four consecutive time points during hospitalization for SCT, yielding a total of 781 interviews. Depression diagnoses were determined on the basis of the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition.

Results

Eighteen (9.0%) and 17 patients (8.5%) met criteria for major and minor depression, respectively. Multivariate Cox regression models found major depression to be predictive of higher 1-year (hazard ratio [HR], 2.59; 95% CI, 1.21 to 5.53; P = .014) and 3-year mortality (HR, 2.04; 95% CI, 1.03 to 4.02; P = .041) but not 5-year mortality (HR, 1.48; 95% CI, 0.76 to 2.87; P = .249). Minor depression had no effect on any mortality outcome. Other multivariate significant predictors of higher mortality were higher regimen toxicity in the 1-, 3-, and 5-year models; older age and acute lymphoblastic leukemia in the 3- and 5-year models; chronic myelogenous leukemia in the 3-year model; and lower functional status and intermediate/higher risk status in the 5-year model. Use of peripheral-blood stem cells predicted lower mortality in the 5-year model.

Conclusion

After adjusting for multiple factors, major depression predicted higher 1- and 3-year mortality among cancer patients after SCT, underscoring the importance of adequate diagnosis and treatment of major depression.
A Process for Measuring the Quality of Cancer Care: The Quality Oncology Practice Initiative
Authors: Neuss Michael N. , Desch Christopher E. , McNiff Kristen K. , Eisenberg Peter D. , Gesme Dean H. , Jacobson Joseph O. , Jahanzeb Mohammad , Padberg Jennifer J. , Rainey John M. , Guo Jeff J. , Simone Joseph V.
Published: August 2005

Purpose

The Quality Oncology Practice Initiative (QOPI) is a practice-based system of quality self-assessment sponsored by the participants and the American Society of Clinical Oncology (ASCO). The process of quality evaluation, development of the pilot questionnaire, and preliminary results are reported.

Methods

Physicians from seven oncology groups developed medical record abstraction measures based on practice guidelines and consensus-supported indicators of quality care. Each practice completed two rounds of records review and received practice and aggregate results. Mean frequencies of responses for each indicator were compared among practices.

Results

Participants universally, if informally, find QOPI helpful, and results show statistically significant variation among practices for several indicators, including assessing pain in patients close to death, documentation of informed consent for chemotherapy, and concordance with granulocytic and erythroid growth factor administration guidelines. Measures with universally high concordance include the use of serotonin antagonist antiemetics according to the ASCO guideline; the presence of a pathology report in the record; the use of chemotherapy flow sheets; and adherence to standard chemotherapy recommendations for patients with certain stages of breast, colon, and rectal cancer. Concordance with quality indicators significantly changed between survey rounds for several measures.

Conclusion

Pilot results indicate that the QOPI process provides a rapid and objective measurement of practice quality that allows comparisons among practices and over time. It also provides a mechanism for measuring concordance with published guidelines. Most importantly, it provides a tool for practice self-examination that can promote excellence in cancer care.
Associations Between Drug Metabolism Genotype, Chemotherapy Pharmacokinetics, and Overall Survival in Patients With Breast Cancer
Authors: Petros William P. , Hopkins Penelope J. , Spruill Susan , Broadwater Gloria , Vredenburgh James J. , Colvin O. Michael , Peters William P. , Jones Roy B. , Hall Jeff , Marks Jeffrey R.
Published: August 2005

Purpose

To evaluate associations between patient survival, pharmacokinetics, and drug metabolism–related genetic polymorphisms in patients receiving a combination chemotherapy regimen for breast cancer.

Patients and Methods

A genotype association study was conducted on 85 chemotherapy-naïve patients with metastatic or inflammatory breast cancer that were evaluated for an extended period after receiving standard-dose chemotherapy followed by high-dose cyclophosphamide, cisplatin, and carmustine. Blood pharmacokinetics were evaluated, and DNA was genotyped for 29 polymorphisms in 17 drug metabolism genes.

Results

Patients with cyclophosphamide plasma exposures above the median (implying slower metabolic activation) had a shorter survival than those below the median (1.8 v 3.8 years, respectively; P = .042). Patients having a variant genotype of cytochrome P450 3A4 displayed higher blood concentrations of parent (inactive) cyclophosphamide with the second and third doses (P = .024 and .028, respectively) in addition to slower cyclophosphamide activation over the three doses (P = .031). Median survival for these patients was 1.3 years compared with 2.7 years for those without the variant (P = .043). Similar results were observed for patients carrying a genetic variant of P450 3A5. Median survival for patients with deletions of glutathione-S-transferase M1 gene was 3.5 v 1.5 years for patients with one or both copies (P = .041). Patients with a polymorphism in a gene regulating metallothionein had lower platinum concentrations and shorter survival (P = .033).

Conclusion

These data suggest that pretreatment evaluation of drug metabolism genes may explain some interindividual differences in both anticancer drug pharmacokinetics and response. The correlations found here may have implications for other commonly used anticancer drugs.
Autoimmunity Correlates With Tumor Regression in Patients With Metastatic Melanoma Treated With Anti–Cytotoxic T-Lymphocyte Antigen-4
Authors: Attia Peter , Phan Giao Q. , Maker Ajay V. , Robinson Michael R. , Quezado Martha M. , Yang James C. , Sherry Richard M. , Topalian Suzanne L. , Kammula Udai S. , Royal Richard E. , Restifo Nicholas P. , Haworth Leah R. , Levy Catherine , Mavroukakis Sharon A. , Nichol Geoff , Yellin Michael J. , Rosenberg Steven A.
Published: August 2005

Purpose

Previously, we reported our experience treating 14 patients with metastatic melanoma using a fully human antibody to cytotoxic T-lymphocyte antigen-4 (anti–CTLA-4) in conjunction with peptide vaccination. We have now treated 56 patients to evaluate two different dose schedules of anti–CTLA-4 and to explore the relationship between autoimmunity and tumor regression.

Patients and Methods

A total of 56 patients with progressive stage IV melanoma were enrolled onto the study. All had Karnofsky performance status ≥ 60% with no prior history of autoimmunity. Twenty-nine patients received 3 mg/kg anti–CTLA-4 every 3 weeks, whereas 27 received 3 mg/kg as their initial dose with subsequent doses reduced to 1 mg/kg every 3 weeks. In both cohorts patients received concomitant vaccination with two modified HLA-A*0201-restricted peptides from the gp100 melanoma-associated antigen, gp100:209-217(210M) and gp100:280-288(288V).

Results

Two patients achieved a complete response (ongoing at 30 and 31 months, respectively) and five patients achieved a partial response (durations of 4, 6, 25+, 26+, and 34+ months, respectively), for an overall objective response rate of 13%. Tumor regression was seen in lung, liver, brain, lymph nodes, and subcutaneous sites. Of 14 patients with grade 3/4 autoimmune toxicity, five (36%) experienced a clinical response compared with only two responses in the 42 patients (5%) with no autoimmune toxicity (P = .008). There were no significant differences in response rate or toxicity between the two dose schedules.

Conclusion

Administration of anti–CTLA-4 monoclonal antibody plus peptide vaccination can cause durable objective responses, which correlate with the induction of autoimmunity, in patients with metastatic melanoma.
Weekly Paclitaxel Improves Pathologic Complete Remission in Operable Breast Cancer When Compared With Paclitaxel Once Every 3 Weeks
Authors: Green Marjorie C. , Buzdar Aman U. , Smith Terry , Ibrahim Nuhad K. , Valero Vicente , Rosales Marguerite F. , Cristofanilli Massimo , Booser Daniel J. , Pusztai Lajos , Rivera Edgardo , Theriault Richard L. , Carter Cynthia , Frye Debra , Hunt Kelly K. , Symmans W. Fraser , Strom Eric A. , Sahin Aysegul A. , Sikov William , Hortobagyi Gabriel N.
Published: August 2005

Purpose

To determine the impact a change in schedule of paclitaxel administration from once every 3 weeks to frequent administration would have on the pathologic complete response (pCR) rate in the breast and lymph nodes for patients with invasive breast cancer treated with primary systemic chemotherapy (PST).

Patients and Methods

Patients with clinical stage I-IIIA breast cancer were randomly assigned to receive PST of paclitaxel doses administered either weekly (for a total of 12 doses of paclitaxel) or once every 3 weeks (four cycles), followed by four cycles of fluorouracil/doxorubicin/cyclophosphamide (FAC) in standard doses every 3 weeks. Two different doses of paclitaxel were used based on lymph node status defined by ultrasound and fine needle aspiration. Clinical response and extent of residual disease in the breast and lymph nodes was assessed after completion of all chemotherapy.

Results

A total of 258 patients were randomly assigned to receive doses of paclitaxel administered either weekly or once every 3 weeks, followed by FAC. Of these 258 patients, 110 patients had histologic lymph node involvement and 148 patients had clinical N0 disease. Weekly paclitaxel followed by FAC was administered to 127 patients and once-every-3-weeks paclitaxel followed by FAC was administered to 131 patients. Clinical response to treatment was similar between groups (P = .25). Patients receiving weekly paclitaxel had a higher pCR rate (28.2%) than patients treated with once-every-3-weeks paclitaxel (15.7%; P = .02), with improved breast conservation rates (P = .05).

Conclusion

The change in schedule of paclitaxel from once every 3 weeks to a more frequent administration significantly improved the ability to eradicate invasive cancer in the breast and lymph nodes.
Osteoclast Responses to Lipopolysaccharide, Parathyroid Hormone and Bisphosphonates in Neonatal Murine Calvaria Analyzed by Laser Scanning Confocal Microscopy
Authors: Suzuki Keiko , Takeyama Sadaaki , Kikuchi Takashi , Yamada Shoji , Sodek Jaro , Shinoda Hisashi
Published: August 2005

Because the development and activity of osteoclasts in bone remodeling is critically dependent on cell-cell and cell-matrix interactions, we used laser confocal microscopy to study the response of osteoclasts to lipopolysaccharide (LPS; 10 μg/ml), parathyroid hormone (PTH; 10−8 M), and bisphosphonates (BPs; 1–25 μM clodronate or 0.1–2.5 μM risedronate) in cultured neonatal calvaria. Following treatment with LPS or PTH (<48 hr), osteopontin (OPN) and the αvβ3 integrin were found colocalized with the actin ring in the sealing zone of actively resorbing osteoclasts. In contrast, non-resorbing osteoclasts in BP-treated cultures showed morphological abnormalities, including retraction of pseudopods and vacuolization of cytoplasm. In the combined presence of LPS and BP, bone-resorbing osteoclasts were smaller and the sealing zone diffuse, reflecting reduced actin, OPN, and β3 integrin staining. Depth analyses of calvaria showed that the area of resorbed bone was filled with proliferating osteoblastic cells that stained for alkaline phosphatase, collagen type I, and bone sialoprotein, regardless of the presence of BPs. These studies show that confocal microscopy of neonatal calvaria in culture can be used to assess the cytological relationships between osteoclasts and osteoblastic cells in response to agents that regulate bone remodeling in situ, avoiding systemic effects that can compromise in vivo studies and artifacts associated with studies of isolated osteoclasts.
Tight Junction Proteins and Perineurial Cells in Neurofibromas
Authors: Pummi Kati P. , Aho Heikki J. , Laato Matti K. , Peltonen Juha T.K. , Peltonen Sirkku A.
Published: August 2005

Cutaneous neurofibromas consist of axonal processes, Schwann cells, fibroblasts, perineurial cells, mast cells, and abundant extracellular matrix. The distribution and role of perineurial cells in neurofibromas has been uncertain, partly because there has not been a specific immunohistochemical marker for perineurial cells. In this study, tight junctions (TJs) of 16 neurofibromas from 12 patients with neurofibromatosis type 1 (NF1) were analyzed using electron microscopy, immunohistochemistry, and Western transfer analysis. Cell-cell contacts with typical ultrastructural morphology of TJs were seen between adjacent perineurial cells surrounding the small nerves and between contacting perineurial cell processes embedded in tumor stroma. Immunohistochemistry showed expression of claudin-1, claudin-3, and ZO-1 in the intercellular junctions of a subpopulation of tumor cells. Occludin was present mainly in perineurium and claudin-5 localized to the blood vessels. Double immunolabelings were used to identify the cell types expressing claudin-1. The results showed that claudin-1 positive cells were also positive for type IV collagen and epithelial membrane antigen but not for S-100 protein. This labeling pattern is consistent with perineurial cell phenotype. Using claudin-1 as a marker, our results showed that clusters of perineurial cells are distributed around the rudimentary nerves within cutaneous neurofibromas and at the periphery of some neurofibromas.
Fractographic Reassessment of the Significance of Fatigue Crack Closure
Authors: Sunder R
Published: August 2005

Experiments were performed on Al-alloy test coupons under specially programmed variable amplitude load sequences to assess crack closure as well as actual microscopic crack extension. Quantitative fractography of the fractures suggests that closure can account for only a fraction of observed load interaction effects. Much of the observed retardation may be attributed to the shielding effect of the overload plastic zone, which can occur even if the crack is fully open. The study also indicates that load sequence effects attributed to notch root stress-strain hysteresis can occur only if closure is absent.
A New Method for Opening Load Determination from Compliance Measurements
Authors: Kujawski D , Stoychev S
Published: August 2005

A brief review of the most popular compliance based methods for determination of the crack opening load is included in the introduction. This review reveals the demand for a noise resistant method that is especially needed in the near-threshold region where a partial crack closure prevails and the existing ASTM method does not calculate the correct opening load. With this in mind, a new technique was developed (‘Q’ method). It uses integration instead of differentiation of the compliance data. It also accounts for the partial crack closure situations. The derivation of the Q method is discussed together with its relation to the ASTM procedure, and both methods were used to analyze experimental data of 2324-T39 and 7475-T7351 Al alloys tested at 0.1 and 0.9 load ratios. On average the crack opening load values from the Q method are smaller by the factor of about 2/π in comparison to those obtained from the ASTM procedure.
Use of ACR Method to Estimate Closure and Residual Stress Free Small Crack Growth Data
Authors: Zonker HR , Bray GH , George K , Garratt MD
Published: August 2005

Life predictions for small cracks emanating from material inhomogeneities or small flaws caused by manufacturing or corrosion damage are becoming increasingly important for several reasons, including: concerns over widespread fatigue damage; a shift in philosophy for fatigue initiation design from stress-life (S-N) to the equivalent initial flaw size (EIFS) approach, and the greater usage of unitized structure. For these reasons, development of accurate fatigue crack growth rate (FCGR) data in the near threshold region is needed, which is not influenced by closure or residual stress. Threshold data ARE often generated from long crack specimens by load shedding as outlined in ASTM E 647. However, this data can be non-conservative and variable due to load history effects caused by crack closure. Generating closure-free short crack FCGR data requires much more sophisticated instrumentation and testing techniques than long crack testing, making it prohibitively expensive to perform on a routine basis. Small crack tests also sample only a small volume of material and typically exhibit large scatter, so multiple tests must be performed in order to determine the typical or average behavior of the material. As a result of these disadvantages, use of long crack tests to estimate short crack behavior is the preferred approach.

The objective of this study was to evaluate the adjusted compliance ratio (ACR) method for obtaining residual stress and closure-free data from long crack tests and to compare the ACR method against the current ASTM opening load method. The ACR method was developed by Donald for estimating the closure-free ΔKeff FCGR curve from standard long crack tests. To evaluate the method's ability to estimate closure-free data, standard ASTM long crack tests and short corner crack tests were conducted on 7075-T651 and 2324-T39 alloys. The ΔKeff FCGR data resulting from the application of the ACR method to the ASTM long crack test results were then compared with the closure-free short corner crack data. Additionally, to assess the method's ability to account for residual stresses, long crack tests using ASTM standard middle crack and compact tension specimens, prepared from alloy 7055-T74511, were conducted, and the resulting ΔKapplied and ΔKeff FCGR data were compared.
Assessment for Decrease in Threshold Stress Intensity Factor (SIF) Range Due to High Maximum SIF
Authors: Meshii T , Ishihara K , Watanabe K
Published: August 2005

In this paper, we consider the decrease in threshold stress intensity factor (SIF) range ΔKth due to high maximum SIF K, which is observed for several materials in the tests with the Kmax constant method when closure-free conditions are realized. We proposed an assessment criterion to predict this phenomenon from the past data for Al and Ti and showed that the criterion is valid also for steels. Finally, we proposed a simplified model to explain the phenomenon, considering the fact that marks of static fracture are observed on the fracture surface.
Notch-Root Elastic-Plastic Strain-Stress in Particulate Metal Matrix Composites Subjected to General Loading Conditions
Authors: Owolabi GM , Singh MNK
Published: August 2005

Determining the stress and strain history at the point of highest stress concentration in particulate metal matrix composites (PMMCs) is complicated, particularly when they have a finite concentration of inclusions, the matrix material in the vicinity of the notch is elastic-plastic, and when multiaxial cyclic loads are applied to the component. In this paper, an analytical tool is developed to approximate notch root elastic-plastic strains and stresses in PMMC components subjected to multiaxial cyclic loads. The model consists of a set of linear relations that can be solved to estimate a notch root elastic-plastic strain and stress history in PMMCs from an elastic analysis. The model is developed using assumptions about notch root behavior, the incremental mean field theory, and the endochronic theory of plasticity. The model presented provides an easy to implement approximation to the otherwise rather complex non-linear problem. The analytical results are compared to the local strains, obtained using 3D image correlation technology, at the depth of a circumferential notch in a PMMC bar subjected to proportional and non-proportionally applied monotonic and cyclic axial-torsional loads. The results of the comparison show that the proposed model works well for the geometry and load paths considered.
Assessment of Plane Stress Tearing in Terms of Various Crack Driving Parameters
Authors: Naumenko VP , Volkov GS
Published: August 2005

The important role of mechanical parameters characterizing the global fracture behavior of a thin rectangular plate is demonstrated through comparison of various approaches to the investigation of ductile tearing at large amounts of stable crack extension. Tensile tests have been performed on middle-cracked specimens at different in-plane constraint states and on cruciform specimens. The latter geometry is treated as a physical counterpart of the basic structural element usually considered in model descriptions of tension- and/or compression-dominant crack geometries. Attention is focused on the simplest practical problem, namely, assessing the critical states of a center through crack under remote uniaxial tension. The case in point is a comprehensive assessment of the structural behavior of a thin-wall component where failure loads, displacements, and subcritical crack extensions must all be predicted from the crack growth data for a laboratory-size specimen of standard geometry.
Methods for Improving the Efficiency of Alpine Ski Equipment Rental Operations
Authors: Ettlinger CF , Shealy J , Johnson RJ
Published: August 2005

The objective of this study was to develop principles and practices which could improve the efficiency and reliability of alpine ski equipment rental facilities operating in compliance with ASTM or ISO rental standards.

Tests were conducted using a commercially available device to measure the release moments of boot/binding combinations, with contact areas between boot and binding alternately in clean and lubricated conditions. Bindings were also tested in combination with a test sole adjustable for length. The study provided a measure of the variability of the components of the release system and an estimate of the system variability experienced by rental facilities using various inspection, maintenance, and dispatch procedures. It also produced guidelines for reducing the need for applying correction factors to the release indicator scales of bindings in the rental inventory.

Among 60 boot/binding combinations the study found that the difference between clean and lubricated tests ranged from 0% to 34% with an overall average difference of 7%, half that observed twenty years ago. The difference in tests comparing actual boots in a lubricated condition with a test sole of the same length in a lubricated condition ranged from +3 Nm to −3 Nm with a mean and standard deviation of less than 1 Nm, a fraction of differences noted in years past. However, release value selection tables currently in common use do not accurately reflect the relationship between boot sole length, release indicator value, and the target release torque. The study found the indicator value displayed in 64 % of the most commonly used cells in these charts varied from the optimal by release indicator increments ranging from −0.5 to +2.5.

The release characteristics of modern alpine rental boot/binding combinations are more predictable and reliable than ten or twenty years ago. However, inspection, maintenance, and dispatch procedures currently in use do not take full advantage of these capabilities. A simple procedure exists for the routine documentation of boot/binding compatibility so that rental procedures can be updated to reflect the true characteristics of contemporary rental products and thereby minimize the potential for time-consuming correction procedures and improve the release retention performance of equipment dispatched to the rental customer.
Development of Electronic Textiles to Transport Data and Power in Future U.S. Military Protective Clothing Systems
Authors: Winterhalter CA , Teverovsky J , Wilson P , Slade J , Farell B , Horowitz W , Tierney E
Published: August 2005

The focus of this paper is on the development of textile-based wearable electronics that can be integrated into military protective clothing. A materials and manufacturing survey was conducted to determine the best performing and most durable materials to withstand the rigors of textile manufacturing and potential military use. Narrow woven technology was selected as the most appropriate manufacturing method. A working wearable narrow fabric version of the Universal Serial Bus (USB), as well as a radiating conductor, were successfully developed and fabricated. Military products developed include components of a personal area network providing data and power transport and a body borne antenna integrated into a load-bearing vest.
The Effect of Dispersant Solubility, Dispersant Dosage, Granule Diameter, and Dome Versus Radial Extrusion on Granule Spontaneity of Disintegration and Resistance to Attrition
Authors: Winowiski T , Lebo S , Gustafsson J
Published: August 2005

Dissolution rate of 16 sulfonated dispersants was measured in both water and 32-0-0 liquid fertilizer. Two dispersants, BNA and UCA, having different dissolution rates, were used to granulate a 70 % Amicarbazone formulation. Extrusions were made on a MG-55 Multigranulator using both the dome and radial modes with 0.8 mm and 1.0 mm screens. BNA and UCA were included at levels of 5, 10, and 15 % of the formulation. The remaining 14 dispersants were compared at fixed levels of 10 % using only the 0.8 mm screen and dome mode. Premix water requirements varied according to dispersant chemistry. Granule disintegration was measured in hard water by number of inversions, ASTM E1945, and CIPAC MT-174. High level of dispersant, slow dissolution rate of dispersant, and larger diameter granules lead to reduced disintegration rate in water. In addition to these factors, disintegration in 32-0-0 was further affected by porosity of the granule.
Determining Nitriding Parameters with Neural Networks
Authors: Filetin T , Žmak I , Novak D
Published: August 2005

The choice of correct plasma nitriding parameters is usually experience-based. There are no successful mathematical models for the nitriding process simulation. An attempt has been made to accurately determine required nitriding time for the specified effective nitriding layer thickness, sum of weight contents of nitride forming elements in steel, and nitriding temperature. Two methods were used to solve this problem: the statistical multiple regression and the artificial neural network. It is not possible to find a regression model that would relate the three variables to nitriding time, whereas good results were achieved with neural networks. The second problem that was investigated was the determination of post-nitriding surface hardness on the basis of three known parameters: nitriding time and temperature, and the sum of weight contents of nitride forming elements in steel. Again, a general regression model was not found, and the neural networks produced very good results.
An Overview of Fundamental and Simulative Performance Tests for Hot Mix Asphalt
Authors: Zhang J , Ray Brown E , Kandhal PS , West R
Published: August 2005

Numerous fundamental and simulative test methods are being used to evaluate the performance of Hot Mix Asphalt (HMA). Permanent deformation, fatigue cracking, thermal cracking, loss of surface friction, and stripping are the five main distress types for HMA pavements. All of these distresses can result in loss of performance, but rutting is the one distress that is most likely to be a sudden failure as a result of unsatisfactory HMA. Other distresses are typically long term and show up after a few years of traffic.

This paper provides a general overview of the fundamental, empirical, and simulative tests for HMA corresponding to each of these five distresses. All test methods have been evaluated in terms of advantages and disadvantages. However, major emphasis has been placed on tests for evaluating permanent deformation.
The Effect of Beta-Quenching in Final Dimension on the Irradiation Growth of Tubes and Channels
Authors: Dahlbäck M , Limbäck M , Hallstadius L , Barberis P , Bunel G , Simonot C , Andersson T , Askeljung P , Flygare J , Lehtinen B , Massih AR
Published: August 2005

The effect of β-quenching performed in the final size of Zircaloy-4 guide tubes and Zircaloy-2 sheets during fabrication process on the products' mechanical properties, crystallographic texture, microstructure, and corrosion behavior has been investigated and presented in this paper. Moreover, the impact of this processing on the irradiation growth of pressurized water reactor Zircaloy-4 guide tubes in a test reactor and Zircaloy-2 fuel channels in boiling water reactors has been evaluated. The results indicate that the irradiation growth rates of the final dimension β-quenched (FDBQ) products are substantially lower than those fabricated by conventional (Standard) techniques. BWR channels irradiated up to a fast neutron fluence of about 9 × 1025 m−2 maintain this low growth behavior. Corrosion properties of FDBQ products have been made similar to that of the Standard material by performing an α-annealing step after the β-quenching. The annealing temperature and annealing time have been optimized in order to obtain good corrosion resistance. In-reactor data on Zircaloy-2 channels irradiated to a fuel assembly exposure of about 50 MWd/kgU indicate similar corrosion performance for the FDBQ and Standard materials. Finally, the in-reactor data on Zircaloy-2 channels show that bowing of the FDBQ and Standard channels is comparable up to a fast neutron fluence of about 7 × 1025 m−2.
Shadow Corrosion Mechanism of Zircaloy
Authors: Lysell G , Nystrand A-C , Ullberg M
Published: August 2005

The mechanism of Zircaloy shadow corrosion was studied theoretically and experimentally. The theoretical study showed shadow corrosion, with a few exceptions, to be remarkably consistent with a galvanic corrosion mechanism. The exceptions may be explained as radiation effects. An experiment was therefore devised to test the galvanic hypothesis, based on the fact that galvanic corrosion requires a closed current loop. Three pieces of Zircaloy cladding with stainless steel counter electrodes were exposed in-pile. Two of the claddings were galvanically coupled to the counters. The third cladding was well insulated by fitting it to a 100 mm sapphire tube. The claddings were irradiated together in oxidizing water chemistry for one reactor period. The galvanically coupled claddings developed shadow corrosion, but not the well insulated cladding.
Microstructure and Growth Mechanism of Oxide Layers Formed on Zr Alloys Studied with Micro-Beam Synchrotron Radiation
Authors: Motta AT , Yilmazbayhan A , Comstock RJ , Partezana J , Sabol GP , Lai B , Cai Z
Published: August 2005

The structures of oxides formed in water and lithiated water on three Zr-based alloys with varied corrosion behavior were studied with micro-beam synchrotron radiation and optical microscopy. Micro-beam synchrotron radiation (0.2 μm spot) has a unique combination of high elemental sensitivity (ppm level) and fine spatial resolution that allowed the determination of various oxide characteristics such as phase content, texture, grain size, and composition as a function of distance from the oxide-metal interface.

Micro-beam X-ray fluorescence shows that the oxides formed in lithiated water have increased levels of Fe absorbed from the autoclave environment indicating greater oxide porosity in these oxides. The phase content, texture, and grain size of oxides were studied in detail using synchrotron radiation micro-beam diffraction for samples corroded in water and lithiated water. A remarkable periodicity was observed in the oxide structures using various techniques including X-ray peak intensities for both monoclinic and tetragonal zirconia, texture, and optical microscopy. The periods were similar to the transition period and were less visible in the oxides that behaved worse in lithiated water. These results are discussed in terms of models of oxide growth and of the differences between alloys.
Damage Dependence of Irradiation Deformation of Zr-2.5Nb Pressure Tubes
Authors: Griffiths M , Christodoulou N , Donohue SA
Published: August 2005

The diametral expansion and elongation rates of Zr-2.5Nb pressure tubes in CANDU™ (CANada Deuterium Uranium) nuclear reactors are important properties that limit their useful life and the maximum power level for reactor operation.

For a given set of operating conditions there is considerable variability in the deformation rates because of the variations in as-fabricated microstructure and chemistry from tube-to-tube — specifically grain size, crystallographic texture, and oxygen content. The as-fabricated microstructure also varies within a given tube, the largest variation occurring along the length, and this is a result of cooling of the tube during the extrusion process. During service in a nuclear reactor, the microstructure evolves further, and this additional change in microstructure is primarily dependent on the rate of radiation damage (determined by the fast neutron flux), the temperature, and the time. Both the fast neutron flux and temperature vary at all points within the pressure tube.

For a given material microstructure, the deformation is a function of the operating conditions: coolant pressure (stress), temperature, and neutron flux. In principle, the deformation rate is a linear function of fast neutron flux, and this is mostly true for fast neutron fluxes of the order of 1017 n.m−2.s−1. Recent analyses of data from pressure tubes measured over long periods of operation in reactor have shown that the steady-state diametral creep rates are not linear with fast neutron flux for fluxes up to about 0.5 × 1017 n.m−2.s−1. A qualitative model has been developed to account for the observed behavior based on the modifying effects of neutron flux and temperature on the microstructure. The model describes the suppression of thermal creep and the transition from thermal to irradiation creep with increasing neutron flux.
Failure of Hydrided Zircaloy-4 Under Equal-Biaxial and Plane-Strain Tensile Deformation
Authors: Glendening A , Koss DA , Motta AT , Pierron ON , Daum RS
Published: August 2005

The fracture behavior of unirradiated Zircaloy-4 containing either solid hydride blisters or hydrided rims has been examined for the contrasting conditions of equal-biaxial and plane-strain tensile deformation at three temperatures (25°, 300°, and 375°C). Cold-worked and stress-relieved Zircaloy-4 sheet containing hydride blisters shows nearly identical failure strains in equal-biaxial and plane-strain tensile deformation for a wide range of blister or rim depths. In all cases, failure strains decrease rapidly with increasing hydride blister or rim thickness, especially in the ≤100 µm range. Test temperature has a significant effect on ductility with failure strains at 300° and 375°C being much greater than at room temperature. The results indicate that the ductility of material containing hydride rims/blisters greater than ≈ 30–40 µm deep is limited by crack growth, which occurs in a mode I manner at 25°C but in a mixed mode I/II manner at ≥300°C (and at higher failure strain levels).
The Effect of Liner Component Iron Content on Cladding Corrosion, Hydriding, and PCI Resistance
Authors: Dahlbäck M , Hallstadius L , Limbäck M , Vesterlund G , Andersson T , Witt P , Izquierdo J , Remartinez B , Diaz M , Sacedon JL , Alvarez A-M , Engman U , Jakobsson R , Massih AR
Published: August 2005

This paper focuses on the effect of liner component Fe content on cladding corrosion, hydriding and Pellet-Cladding Interaction (PCI) resistance. A multitude of experimental techniques is used to evaluate the various properties. The PCI resistance is evaluated through mandrel testing of un-irradiated claddings as well as by ramp tests of pre-irradiated fuel segments in the Studsvik R2 reactor. The results from the mandrel testing indicate that an increase of the iron concentration from 0.05 to 0.21 wt% has a rather small impact on the PCI properties. The ramp data, on the other hand, show a clear decrease in the PCI resistance as the Fe content approaches and exceeds 0.19 wt%. The phenomena involved in secondary degradation are complex, and separate tests are used to evaluate the corrosion resistance in steam as well as the hydriding resistance in pure hydrogen. The corrosion test includes cladding tubes with ZrSn-liner components with iron concentrations from 0.025 to 0.21 wt%. The results show that the corrosion resistance is dramatically increased as the Fe content is increased from 0.025 to 0.05–0.06 wt%, but that a further increase of the Fe concentration only has a minor impact on the corrosion resistance. However, increasing the Fe content from 0.05 to 0.21 wt% increases the hydrogen pick-up rate. The 0.21 wt% Fe liner has a significantly higher density of Secondary Phase Particles (SPPs) as well as slightly larger SPPs than the 0.05 wt% Fe liner. Consequently, it is believed that the SPPs offer sites where hydrogen can easily be absorbed into the Zr-based material, and the frequency of these sites is important for the hydrogen pick-up rate. It is finally concluded that even though the optimization of the Fe concentration in the liner is complex, an iron level regime exists that provides a good balance of resistance against PCI, corrosion, and hydriding.